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Sample records for cell-surface mhc class

  1. Human MHC class I antigens are associated with a 90-kDa cell surface protein.

    Science.gov (United States)

    Ferm, M T; Grönberg, A

    1991-08-01

    Human MHC class I proteins are expressed on almost all nucleated cells as a heavy chain (about 45 kDa) non-covalently associated with beta 2-microglobulin (12 kDa). In this report we show that MHC class I (MHC-I) proteins can also be associated with a 90-kDa protein in the cell membrane. Surface-radiolabelled cells were treated with dithiobis succinimidyl propionate (DSP) in order to preserve multimer protein complexes during cell lysis. The lysates were immunoprecipitated and analysed by SDS-PAGE and autoradiography. Immunoprecipitation of human MHC-I proteins co-precipitated another protein of about 90 kDa in molecular weight-p90. p90 was coprecipitated from all the MHC-I expressing cells tested: U937, Raji, Molt-4 and IFN-gamma treated K562, but not from untreated, MHC-I negative K562. A 90-kDa protein was also co-precipitated with MHC-I from fresh peripheral blood mononuclear cells (PBMC). Furthermore, p90 was coprecipitated by different MoAbs to the MHC-I heavy chain or beta 2-microglobulin, but not by control antibodies. Two additional co-precipitating proteins at 34 kDa and 28 kDa were seen in MHC-I precipitates from Raji cells. Our results suggest that MHC-I proteins and the 90-kDa protein are associated in the cell membrane, probably by a close but weak, non-covalent interaction. Two additional cell surface proteins at 34 kDa and 28 kDa seem to be MHC-I associated on Raji Burkitt's lymphoma cells.

  2. High-risk human papillomavirus E7 expression reduces cell-surface MHC class I molecules and increases susceptibility to natural killer cells

    DEFF Research Database (Denmark)

    Bottley, G; Watherston, O G; Hiew, Y-L;

    2007-01-01

    killer (NK) cells. Tetracycline-regulated induction of HPV16 E7 resulted in reduced expression of cell surface MHC class I molecules and increased NK cell killing. Our results suggest that, for HPV-associated malignancies, reduced MHC class I expression is the result of an active immune evasion strategy...

  3. CD40-induced aggregation of MHC class II and CD80 on the cell surface leads to an early enhancement in antigen presentation.

    Science.gov (United States)

    Clatza, Abigail; Bonifaz, Laura C; Vignali, Dario A A; Moreno, José

    2003-12-15

    Ligation of CD40 on B cells increases their ability to present Ag and to activate MHC class II (MHC-II)-restricted T cells. How this occurs is not entirely clear. In this study we demonstrate that CD40 ligation on Ag-presenting B cells (APC) for a short period between 30 min and 3 h has a rapid, augmenting effect on the ability of a B cell line and normal B cells to activate T cells. This is not due to alterations in Ag processing or to an increase in surface expression of CD80, CD86, ICAM-1, or MHC-II. This effect is particularly evident with naive, resting T lymphocytes and appears to be more pronounced under limiting Ag concentrations. Shortly after CD40 ligation on a B cell line, MHC-II and CD80 progressively accumulated in cholesterol-enriched microdomains on the cell surface, which correlated with an initial enhancement in their Ag presentation ability. Moreover, CD40 ligation induced a second, late, more sustained enhancement of Ag presentation, which correlates with a significant increase in CD80 expression by APC. Thus, CD40 signaling enhances the efficiency with which APC activate T cells by at least two related, but distinct, mechanisms: an early stage characterized by aggregation of MHC-II and CD80 clusters, and a late stage in which a significant increase in CD80 expression is observed. These results raise the possibility that one important role of CD40 is to contribute to the formation of the immunological synapse on the APC side.

  4. Organizing MHC Class II Presentation

    Directory of Open Access Journals (Sweden)

    David R Fooksman

    2014-04-01

    Full Text Available Major histocompatibility complex (MHC class II molecules are ligands for CD4+ T cells and are critical for initiating the adaptive immune response. This review is focused on what is currently known about MHC class II organization at the plasma membrane of antigen presenting cells and how this affects antigen presentation to T cells. The organization and diffusion of class II molecules have been measured by a variety of biochemical and microscopic techniques. Membrane lipids and other proteins have been implicated in MHC class II organization and function. However, when compared with the organization of MHC class I or TCR complexes, much less is known about MHC class II. Since clustering of T cell receptors occurs during activation, the organization of MHC molecules prior to recognition and during synapse formation may be critical for antigen presentation.

  5. Characterization of structural features controlling the receptiveness of empty class II MHC molecules

    DEFF Research Database (Denmark)

    Rupp, Bernd; Günther, Sebastian; Makhmoor, Talat;

    2011-01-01

    MHC class II molecules (MHC II) play a pivotal role in the cell-surface presentation of antigens for surveillance by T cells. Antigen loading takes place inside the cell in endosomal compartments and loss of the peptide ligand rapidly leads to the formation of a non-receptive state of the MHC mol...

  6. The MHC class I genes of zebrafish.

    Science.gov (United States)

    Dirscherl, Hayley; McConnell, Sean C; Yoder, Jeffrey A; de Jong, Jill L O

    2014-09-01

    Major histocompatibility complex (MHC) molecules play a central role in the immune response and in the recognition of non-self. Found in all jawed vertebrate species, including zebrafish and other teleosts, MHC genes are considered the most polymorphic of all genes. In this review we focus on the multi-faceted diversity of zebrafish MHC class I genes, which are classified into three sequence lineages: U, Z, and L. We examine the polygenic, polymorphic, and haplotypic diversity of the zebrafish MHC class I genes, discussing known and postulated functional differences between the different class I lineages. In addition, we provide the first comprehensive nomenclature for the L lineage genes in zebrafish, encompassing at least 15 genes, and characterize their sequence properties. Finally, we discuss how recent findings have shed new light on the remarkably diverse MHC loci of this species.

  7. MHC Class Ⅰ Antigen Presentation- Recently Trimmed and Well Presented

    Institute of Scientific and Technical Information of China (English)

    Barry Flutter; Bin Gao

    2004-01-01

    Presentation of antigenic peptide to T cells by major histocompatibility complex (MHC) class Ⅰ molecules is the key to the cellular immune response. Non-self intracellular proteins are processed into short peptides and transported into endoplasmic reticulum (ER) where they are assembled with class Ⅰ molecules assisted by several chaperone proteins to form trimeric complex. MHC class Ⅰ complex loaded with optimised peptides travels to the cell surface of antigen presentation cells to be recognised by T cells. The cells presenting non-self peptides are cleared by CD8 positive T cells. In order to ensure that T cells detect an infection or mutation within the target cells the process of peptide loading and class Ⅰ expression must be carefully regulated. Many of the cellular components involved in antigen processing and class Ⅰ presentation are known and their various functions are now becoming clearer. Cellular & Molecular Immunology. 2004;1(1):22-30.

  8. MHC Class I Antigen Presentation- Recently Trimmed and Well Presented

    Institute of Scientific and Technical Information of China (English)

    BarryFlutter; BinGao

    2004-01-01

    Presentation of antigenic peptide to T cells by major histocompatibility complex (MHC) class I molecules is the key to the cellular immune response. Non-self intracellular proteins are processed into short peptides and transported into endoplasmic reticulum (ER) where they are assembled with class I molecules assisted by several chaperone proteins to form trimeric complex. MHC class I complex loaded with optimised peptides travels to the cell surface of antigen presentation cells to be recognised by T cells. The cells presenting non-self peptides are cleared by CD8 positive T cells. In order to ensure that T cells detect an infection or mutation within the target cells the process of peptide loading and class I expression must be carefully regulated. Many of the cellular components involved in antigen processing and class I presentation are known and their various functions are now becoming clearer. Cellular & Molecular Immunology. 2004;1(1):22-30.

  9. Molecular basis for the control of motor-based transport of MHC class II compartments

    NARCIS (Netherlands)

    Rocha, Nuno

    2008-01-01

    Antigen presentation by MHC class II is critical for immune responses against pathogens and tumors. Antigen loading occurs primarily in lysosomal-related organelles (LROs) known as MIICs. Ultimately, the MHC II-peptide complexes are transported for cell surface display. Here, we study intracellular

  10. The prognostic role of classical and nonclassical MHC class I expression in endometrial cancer

    NARCIS (Netherlands)

    Bijen, C.B.; Bantema-Joppe, E.J.; de Jong, Renske; Leffers, N.; Mourits, M.J.; Eggink, Henk F.; van der Zee, A.G.; Hollema, H.; de Bock, G.H.; Nijman, H.W.

    2010-01-01

    The aim of this study was to investigate classical MHC class I and nonclassical MHC (human leukocyte antigen-G [HLA-GJ) expression in a large cohort of patients with endometrial cancer, to determine the prognostic value of these cell surface markers and their relation with clinicopathological variab

  11. Rational design of class I MHC ligands

    Science.gov (United States)

    Rognan, D.; Scapozza, L.; Folkers, G.; Daser, Angelika

    1995-04-01

    From the knowledge of the three-dimensional structure of a class I MHC protein, several non natural peptides were designed in order to either optimize the interactions of one secondary anchor amino acid with its HLA binding pocket or to substitute the non interacting part with spacer residues. All peptides were synthesized and tested for binding to the class I MHC protein in an in vitro reconstitution assay. As predicted, the non natural peptides present an enhanced binding to the HLA-B27 molecule with respect to their natural parent peptides. This study constitutes the first step towards the rational design of non peptidic MHC ligands that should be very promising tools for the selective immunotherapy of autoimmune diseases.

  12. MHC Class II epitope predictive algorithms

    DEFF Research Database (Denmark)

    Nielsen, Morten; Lund, Ole; Buus, S;

    2010-01-01

    Major histocompatibility complex class II (MHC-II) molecules sample peptides from the extracellular space, allowing the immune system to detect the presence of foreign microbes from this compartment. To be able to predict the immune response to given pathogens, a number of methods have been...

  13. Cell surface appearance of unexpected host MHC determinants on thymocytes from radiation bone marrow chimeras

    International Nuclear Information System (INIS)

    The phenotypic appearance of cell surface antigens on murine thymocytes from long-term radiation bone marrow chimeras was analyzed using indirect immunofluorescence and flow microfluorometry. Cells maturing in the thymi of these mice were typed for MHC (Kk, I-Ak, H-2b, Kb, and Ib) and non-MHC (Lty 1, Ly 9, and TL) determinants. All cells were of donor origin as determined by non-MHC (Ly) phenotype in P1 leads to P2, P1 x P2 leads to P1, and P1 leads to P2 radiation chimeras. In contrast, the MHC phenotypes of these thymocytes were markedly affected by the host environment. Specifically, H-2 and I-A determinants of both parental phenotypes were detected on thymocytes from P1 leads to P1 x P2 chimeras; I-A determinants of host phenotype were present, whereas I-A determinants of donor phenotype were reduced on thymocytes from P1 x P2 leads to P1 chimeras; and thymocytes from P1 leads to P2 chimeras possessed H-2 and I-A determinants of host phenotype but showed reduction of donor I-A phenotype determinants. The appearance of host cell surface H-2 and I-A determinants on thymocytes from chimeras closely parallels the functional recognition of MHC determinants by T cells from chimeric mice and thus may be significantly related to the development of the self-recognition repertoire by maturing T cells

  14. AN MHC class I immune evasion gene of Marek's disease virus

    Science.gov (United States)

    Marek's disease virus (MDV) is a widespread a-herpesvirus of chickens that causes T cell tumors. Acute, but not latent, MDV infection has previously been shown to lead to downregulation of cell-surface MHC class I (Virology 282:198–205 (2001)), but the gene(s) involved have not been identified. Here...

  15. Locus-specific de novo methylation down-regulates MHC class I in S49 lymphomas

    Energy Technology Data Exchange (ETDEWEB)

    Rubocki, R.J.; Berrigan, B.E.; Specks, S.L. [Univ. of Nebraska Medical Center, Omaha, NE (United States)] [and others

    1996-06-01

    Several tumors from distinct cell lineages can modulate their surface expression of key molecules, thereby avoiding recognition and elimination by the immune system. One group of molecules that has demonstrated this altered expression is encoded by the major histocompatibility complex (MHC) class I genes. The MHC encodes for a large multigene family of highly polymorphic class I molecules that are expressed on the cell surface of most nucleated cells. Class I molecules function as receptors for peptides derived from self or foreign (e.g., viral, tumor) proteins, thereby facilitating immune surveillance against infected or malignant cells. 39 refs., 6 figs., 1 tab.

  16. Prediction of MHC class I binding peptides, using SVMHC

    Directory of Open Access Journals (Sweden)

    Elofsson Arne

    2002-09-01

    Full Text Available Abstract Background T-cells are key players in regulating a specific immune response. Activation of cytotoxic T-cells requires recognition of specific peptides bound to Major Histocompatibility Complex (MHC class I molecules. MHC-peptide complexes are potential tools for diagnosis and treatment of pathogens and cancer, as well as for the development of peptide vaccines. Only one in 100 to 200 potential binders actually binds to a certain MHC molecule, therefore a good prediction method for MHC class I binding peptides can reduce the number of candidate binders that need to be synthesized and tested. Results Here, we present a novel approach, SVMHC, based on support vector machines to predict the binding of peptides to MHC class I molecules. This method seems to perform slightly better than two profile based methods, SYFPEITHI and HLA_BIND. The implementation of SVMHC is quite simple and does not involve any manual steps, therefore as more data become available it is trivial to provide prediction for more MHC types. SVMHC currently contains prediction for 26 MHC class I types from the MHCPEP database or alternatively 6 MHC class I types from the higher quality SYFPEITHI database. The prediction models for these MHC types are implemented in a public web service available at http://www.sbc.su.se/svmhc/. Conclusions Prediction of MHC class I binding peptides using Support Vector Machines, shows high performance and is easy to apply to a large number of MHC class I types. As more peptide data are put into MHC databases, SVMHC can easily be updated to give prediction for additional MHC class I types. We suggest that the number of binding peptides needed for SVM training is at least 20 sequences.

  17. Chlamydia trachomatis Immune Evasion via Downregulation of MHC Class I Surface Expression Involves Direct and Indirect Mechanisms

    OpenAIRE

    Ibana, Joyce A.; Schust, Danny J.; Jun Sugimoto; Takeshi Nagamatsu; Greene, Sheila J.; Alison J. Quayle

    2011-01-01

    Genital C. trachomatis infections typically last for many months in women. This has been attributed to several strategies by which C. trachomatis evades immune detection, including well-described methods by which C. trachomatis decreases the cell surface expression of the antigen presenting molecules major histocompatibility complex (MHC) class I, MHC class II, and CD1d in infected genital epithelial cells. We have harnessed new methods that allow for separate evaluation of infected and uni...

  18. MHC class I is functionally associated with antigen receptors in human T and B lymphomas

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Jacoby, B F; Skov, S;

    1996-01-01

    We have studied the antibody-induced effect of cross-linking the major histocompatibility complex class I (MHC-I) in human T leukemic cells (Jurkat) and human B lymphoma cells (Solubo, Burkitts lymphoma) on intracellular [Ca2+]i levels. The increase in [Ca2+]i after MHC-I cross-linking in Jurkat...... lines the increase in [Ca2+]i after MHC-I cross-linking caused upregulation of CD69, an early marker of activation. When studying the effect of MHC-I cross-linking on the TCR- and B cell antigen receptor (BCR)- mediated increase in [Ca2+]i, respectively, we observed that MHC-I had a costimulatory effect......, respectively, were positively correlated with the level of MHC-I expressed on the cell surface. These observations suggest two different roles in signal transduction for the MHC-I molecules in the T and B cells studied. First, by themselves MHC-I complexes are able to induce activation of intracellular second...

  19. The β2-microglobulin-free heterodimerization of rhesus monkey MHC class I A with its normally spliced variant reduces the ubiquitin-dependent degradation of MHC class I A.

    Science.gov (United States)

    Dai, Zheng-Xi; Zhang, Gao-Hong; Zhang, Xi-He; Xia, Hou-Jun; Li, Shao-You; Zheng, Yong-Tang

    2012-03-01

    The MHC class I (MHC I) molecules play a pivotal role in the regulation of immune responses by presenting antigenic peptides to CTLs and by regulating cytolytic activities of NK cells. In this article, we show that MHC I A in rhesus macaques can be alternatively spliced, generating a novel MHC I A isoform (termed "MHC I A-sv1") devoid of α(3) domain. Despite the absence of β2-microglobulin (β2m), the MHC I A-sv1 proteins reached the cell surface of K562-transfected cells as endoglycosidase H-sensitive glycoproteins that could form disulfide-bonded homodimers. Cycloheximide-based protein chase experiments showed that the MHC I A-sv1 proteins were more stable than the full-length MHC I A in transiently or stably transfected cell lines. Of particular interest, our studies demonstrated that MHC I A-sv1 could form β2m-free heterodimers with its full-length protein in mammalian cells. The formation of heterodimers was accompanied by a reduction in full-length MHC I A ubiquitination and consequent stabilization of the protein. Taken together, these results demonstrated that MHC I A-sv1 and MHC I A can form a novel heterodimeric complex as a result of the displacement of β2m and illustrated the relevance of regulated MHC I A protein degradation in the β2m-free heterodimerization-dependent control, which may have some implications for the MHC I A splice variant in the fine tuning of classical MHC I A/TCR and MHC I A/killer cell Ig-like receptor interactions.

  20. Accurate pan-specific prediction of peptide-MHC class II binding affinity with improved binding core identification

    DEFF Research Database (Denmark)

    Andreatta, Massimo; Karosiene, Edita; Rasmussen, Michael;

    2015-01-01

    A key event in the generation of a cellular response against malicious organisms through the endocytic pathway is binding of peptidic antigens by major histocompatibility complex class II (MHC class II) molecules. The bound peptide is then presented on the cell surface where it can be recognized ...

  1. Orf virus interferes with MHC class I surface expression by targeting vesicular transport and Golgi

    Directory of Open Access Journals (Sweden)

    Rohde Jörg

    2012-07-01

    Full Text Available Abstract Background The Orf virus (ORFV, a zoonotic Parapoxvirus, causes pustular skin lesions in small ruminants (goat and sheep. Intriguingly, ORFV can repeatedly infect its host, despite the induction of a specific immunity. These immune modulating and immune evading properties are still unexplained. Results Here, we describe that ORFV infection of permissive cells impairs the intracellular transport of MHC class I molecules (MHC I as a result of structural disruption and fragmentation of the Golgi apparatus. Depending on the duration of infection, we observed a pronounced co-localization of MHC I and COP-I vesicular structures as well as a reduction of MHC I surface expression of up to 50%. These subversion processes are associated with early ORFV gene expression and are accompanied by disturbed carbohydrate trimming of post-ER MHC I. The MHC I population remaining on the cell surface shows an extended half-life, an effect that might be partially controlled also by late ORFV genes. Conclusions The presented data demonstrate that ORFV down-regulates MHC I surface expression in infected cells by targeting the late vesicular export machinery and the structure and function of the Golgi apparatus, which might aid to escape cellular immune recognition.

  2. Immunotherapy augments the effect of 5-azacytidine on HPV16-associated tumours with different MHC class I-expression status

    Science.gov (United States)

    Šímová, J; Polláková, V; Indrová, M; Mikyšková, R; Bieblová, J; Štěpánek, I; Bubeník, J; Reiniš, M

    2011-01-01

    Background: Epigenetic mechanisms have important roles in the tumour escape from immune responses, such as in MHC class I downregulation or altered expression of other components involved in antigen presentation. Chemotherapy with DNA methyltransferase inhibitors (DNMTi) can thus influence the tumour cell interactions with the immune system and their sensitivity to immunotherapy. Methods: We evaluated the therapeutic effects of the DNMTi 5-azacytidine (5AC) against experimental MHC class I-deficient and -positive tumours. The 5AC therapy was combined with immunotherapy, using a murine model for HPV16-associated tumours. Results: We have demonstrated 5AC additive effects against MHC class I-positive and -deficient tumours when combined with unmethylated CpG oligodeoxynucleotides or with IL-12-producing cellular vaccine. The efficacy of the combined chemoimmunotherapy against originally MHC class I-deficient tumours was partially dependent on the CD8+-mediated immune responses. Increased cell surface expression of MHC class I cell molecules, associated with upregulation of the antigen-presenting machinery-related genes, as well as of genes encoding selected components of the IFNγ-signalling pathway in tumours explanted from 5AC-treated animals, were observed. Conclusion: Our data suggest that chemotherapy of MHC class I-deficient tumours with 5AC combined with immunotherapy is an attractive setting in the treatment of MHC class I-deficient tumours. PMID:22015556

  3. Modulation of MHC class-I molecules on melanoma cells after photodynamic treatment

    International Nuclear Information System (INIS)

    Full text: Endogenous antigenic peptides are presented in the context of MHC class-I molecules on the cell surface for recognition by CD8+ T lymphocytes. Down-regulation of MHC molecules is a frequently observed strategy of tumor cells to escape immune attack. E.g., B16 melanoma is characterized by extremely low MHC-I surface expression and high tumorigenicity in syngeneic mice. Generally, the efficiency of photodynamic therapy is low for melanotic tumors. On the other hand, PDT has been shown capable of inducing anti-tumoral immunity. Therefore, we investigated the effect of PDT treatment in vitro on the MHC class-I surface expression of surviving B16 cells. When sensitized with 50 ng/mL hypericin and then irradiated the viability of the cells gradually decreased with increasing light dose. However, with 4 J/cm2 50 % of cells were still viable after 24 hours. Analysis by flow cytometry revealed that a subpopulation of these cells had significantly elevated the surface density of MHC class-I molecules (fluorescence intensity approx. 5-fold over that of untreated cells). These findings suggest that repetitive PDT might facilitate CTL-mediated cytolysis of tumor cells and might, therefore, synergize with immunotherapeutic approaches for at least some tumors. (author)

  4. DNA sequence of the Peromyscus leucopus MHC class II gene Aa (MhcPeleAa)

    Energy Technology Data Exchange (ETDEWEB)

    Crew, M.D.; Bates, L.M. [Univ. of Arkansas for Medical Sciences, Little Rock, AR (United States)

    1996-09-01

    The genus Peromyscus has been extensively studied by populations biologists and ecologists for over eighty years, with P. leucopus (the white-footed mouse) being one of the most intensively investigated species. Polymorphic major histocompatibility complex (MHC) genes have proven useful in population genetic studies and might be helpful in understanding the population dynamics of Peromyscus species which are ubiquitously distributed over North and Central America. Polymorphism of P. leucopus MHC (MhcPele) class II genes was evident by restriction fragment length polymorphism (RFLP) analyses using human and mouse probes and Pele class II loci exhibited degrees of polymorphism similar to H2 class II genes (A-like>E-like). 8 refs., 2 figs.

  5. MHC class I molecules are enriched in caveolae but do not enter with simian virus 40.

    Science.gov (United States)

    Anderson, H A; Chen, Y; Norkin, L C

    1998-06-01

    Simian virus 40 (SV40) binds to MHC class I molecules anywhere on the cell surface and then enters through caveolae. The fate of class I molecules after SV40 binding is not known. Sensitivity of 125I-surface-labelled class I molecules to papain cleavage was used to distinguish internalized class I molecules from class I molecules remaining at the cell surface. Whereas the caveolae-enriched membrane microdomain was found to also be enriched for class I molecules, no internalized papain-resistant 125I-surface-labelled class I molecules could be detected at any time in either control cells or in cells preadsorbed with saturating amounts of SV40. Instead, 125I-surface-labelled class I molecules, as well as preadsorbed 125I-labelled anti-class I antibodies, accumulated in the medium, coincident with the turnover of class I molecules at the cell surface. The class I heavy chains that accumulated in the medium were truncated and their release was specifically prevented by the metalloprotease inhibitor 1,10-phenanthroline. Thus, whereas class I molecules mediate SV40 binding, they do not appear to mediate SV40 entry.

  6. Ubiquitination by March-I prevents MHC class II recycling and promotes MHC class II turnover in antigen-presenting cells.

    Science.gov (United States)

    Cho, Kyung-Jin; Walseng, Even; Ishido, Satoshi; Roche, Paul A

    2015-08-18

    MHC class II (MHC-II)-dependent antigen presentation by antigen-presenting cells (APCs) is carefully controlled to achieve specificity of immune responses; the regulated assembly and degradation of antigenic peptide-MHC-II complexes (pMHC-II) is one aspect of such control. In this study, we have examined the role of ubiquitination in regulating pMHC-II biosynthesis, endocytosis, recycling, and turnover in APCs. By using APCs obtained from MHC-II ubiquitination mutant mice, we find that whereas ubiquitination does not affect pMHC-II formation in dendritic cells (DCs), it does promote the subsequent degradation of newly synthesized pMHC-II. Acute activation of DCs or B cells terminates expression of the MHC-II E3 ubiquitin ligase March-I and prevents pMHC-II ubiquitination. Most importantly, this change results in very efficient pMHC-II recycling from the surface of DCs and B cells, thereby preventing targeting of internalized pMHC-II to lysosomes for degradation. Biochemical and functional assays confirmed that pMHC-II turnover is suppressed in MHC-II ubiquitin mutant DCs or by acute activation of wild-type DCs. These studies demonstrate that acute APC activation blocks the ubiquitin-dependent turnover of pMHC-II by promoting efficient pMHC-II recycling and preventing lysosomal targeting of internalized pMHC-II, thereby enhancing pMHC-II stability for efficient antigen presentation to CD4 T cells.

  7. Evolution of MHC class I in the Order Crocodylia

    DEFF Research Database (Denmark)

    Jaratlerdsiri, Weerachai; Isberg, Sally R; Higgins, Damien P;

    2014-01-01

    The major histocompatibility complex (MHC) is a dynamic genomic region with an essential role in the adaptive immunity of jawed vertebrates. The evolution of the MHC has been dominated by gene duplication and gene loss, commonly known as the birth-and-death process. Evolutionary studies of the MHC...... have mostly focused on model species. However, the investigation of this region in non-avian reptiles is still in its infancy. To provide insights into the evolutionary mechanisms that have shaped the diversity of this region in the Order Crocodylia, we investigated MHC class I exon 3, intron 3......, and exon 4 across 20 species of the families Alligatoridae and Crocodilidae. We generated 124 DNA sequences and identified 31 putative functional variants as well as 14 null variants. Phylogenetic analyses revealed three gene groups, all of which were present in Crocodilidae but only one in Alligatoridae...

  8. Selection of Proteins for Human MHC Class Ⅱ Presentation

    Institute of Scientific and Technical Information of China (English)

    LiJiang; OleLund; JinquanTan

    2005-01-01

    We investigated the predicted function of proteins eluded from human MHC class Ⅱ molecules. Peptides that are presented by MHC class Ⅱ were obtained from the SYFPEITH! database and the corresponding proteins were found in the SWISSPROT database. The functions of these proteins were predicted using the protfun server. Our analysis showed that human proteins presented by MHC class Ⅱ molecules are likely to be in the cell envelope, be a receptor or involved in immune responses. Presented proteins from bacteria and virus, on the other hand, are more likely to be involved in regulatory functions, translation, transcription as well as replication. These results can lead to better understanding the autoimmunity and the response to infections. Cellular & Molecular Immunology. 2005; 2(1):49-56.

  9. Selection of Proteins for Human MHC Class Ⅱ Presentation

    Institute of Scientific and Technical Information of China (English)

    Li Jiang; Ole Lund; Jinquan Tan

    2005-01-01

    We investigated the predicted function of proteins eluded from human MHC class Ⅱ molecules. Peptides that are presented by MHC class Ⅱ were obtained from the SYFPEITHI database and the corresponding proteins were found in the SWISSPROT database. The functions of these proteins were predicted using the protfun server. Our analysis showed that human proteins presented by MHC class Ⅱ molecules are likely to be in the cell envelope, be a receptor or involved in immune responses. Presented proteins from bacteria and virus, on the other hand, are more likely to be involved in regulatory functions, translation, transcription as well as replication. These results can lead to better understanding the autoimmunity and the response to infections.

  10. The MHC class II ligand lymphocyte activation gene-3 is co-distributed with CD8 and CD3-TCR molecules after their engagement by mAb or peptide-MHC class I complexes.

    Science.gov (United States)

    Hannier, S; Triebel, F

    1999-11-01

    Previous studies indicated that signaling through lymphocyte activation gene-3 (LAG-3), a MHC class II ligand, induced by multivalent anti-receptor antibodies led to unresponsiveness to TCR stimulation. Here, lateral distribution of the LAG-3 molecules and its topological relationship (mutual proximity) to the TCR, CD8, CD4, and MHC class I and II molecules were studied in the plasma membrane of activated human T cells in co-capping experiments and conventional fluorescence microscopy. Following TCR engagement by either TCR-specific mAb or MHC-peptide complex recognition in T-B cell conjugates, LAG-3 was found to be specifically associated with the CD3-TCR complex. Similarly, following CD8 engagement LAG-3 and CD8 were co-distributed on the cell surface while only a low percentage of CD4-capped cells displayed LAG-3 co-caps. In addition, LAG-3 was found to be associated with MHC class II (i.e. DR, DP and DQ) and partially with MHC class I molecules. The supramolecular assemblies described here between LAG-3, CD3, CD8 and MHC class II molecules may result from an organization in raft microdomains, a phenomenon known to regulate early events of T cell activation.

  11. Expression of classMHC molecule, HSP70 and TAP in human hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ling Deng; Wei Chen; Mei-Ying Cai; Da-Peng Wei

    2003-01-01

    AIM: To demonstrate whether classMHC molecule,transporter associated with antigen processing (TAP), and heat-shock proteion70 (HSP70) expressed in liver cancer cells before the design and construction of CTL vaccine against hepatocellular carcinoma (HCC).METHODS: We studied 30 HCC specimens by labeled streptavidin biotin (LSAB) method of immunohistochemistry.RESULTS: The results showed that the majority of HCC cells investigated naturally expressed classMHC and TAP,which were different from other tumor cells. Furthermore,we found that HSP70 expressed not only in cellular cytoplasm, but also on the cell surface in HCC.CONCLUSION: Our findings indicate that our understanding about immune escape mechanisms employed by HCC cells may be further improved. It is important to design and construct CTL vaccine against HCC.

  12. In vivo role of ER-associated peptidase activity in tailoring peptides for presentation by MHC class Ia and class Ib molecules

    OpenAIRE

    Yan, Jingbo; Parekh, Vrajesh V.; Mendez-Fernandez, Yanice; Olivares-Villagómez, Danyvid; Dragovic, Srdjan; Hill, Timothy; Roopenian, Derry C.; Joyce, Sebastian; Van Kaer, Luc

    2006-01-01

    Endoplasmic reticulum (ER)-associated aminopeptidase (ERAP)1 has been implicated in the final proteolytic processing of peptides presented by major histocompatibility complex (MHC) class I molecules. To evaluate the in vivo role of ERAP1, we have generated ERAP1-deficient mice. Cell surface expression of the class Ia molecules H-2Kb and H-2Db and of the class Ib molecule Qa-2 was significantly reduced in these animals. Although cells from mutant animals exhibited reduced capacity to present s...

  13. MHC class II polymorphisms, autoreactive T-cells and autoimmunity

    Directory of Open Access Journals (Sweden)

    Sue eTsai

    2013-10-01

    Full Text Available Major histocompatibility complex (MHC genes, also known as human leukocyte antigen genes (HLA in humans, are the prevailing contributors of genetic susceptibility to autoimmune diseases such as Type 1 Diabetes (T1D, Multiple Sclerosis (MS, and Rheumatoid arthritis (RA, among others (Todd and Wicker, 2001;MacKay et al., 2002;Hafler et al., 2007. Although the pathways through which MHC molecules afford autoimmune risk or resistance remain to be fully mapped out, it is generally accepted that they do so by shaping the central and peripheral T cell repertoires of the host towards autoimmune proclivity or resistance, respectively. Disease-predisposing MHC alleles would both spare autoreactive thymocytes from central tolerance and bias their development towards a pathogenic phenotype. Protective MHC alleles, on the other hand, would promote central deletion of autoreactive thymocytes and skew their development towards non-pathogenic phenotypes. This interpretation of the data is at odds with two other observations: that in MHC-heterozygous individuals, resistance is dominant over susceptibility; and that it is difficult to understand how deletion of one or a few clonal autoreactive T cell types would suffice to curb autoimmune responses driven by hundreds if not thousands of autoreactive T cell specificities. This review provides an update on current advances in our understanding of the mechanisms underlying MHC class II-associated autoimmune disease susceptibility and/or resistance and attempts to reconcile these seemingly opposing concepts.

  14. Simian virus 40 infection via MHC class I molecules and caveolae.

    Science.gov (United States)

    Norkin, L C

    1999-04-01

    MHC class I molecules are a necessary component of the cell surface receptor for simian virus 40 (SV40). After binding to class I molecules, SV40 enters cells via a unique endocytic pathway that involves caveolae, rather than clathrin-coated pits. This pathway is dependent on a transmembrane signal that SV40 transmits from the cell surface. Furthermore, it delivers SV40 to the endoplasmic reticulum, rather than to the endosomal/lysosomal compartment, which is the usual target for endocytic traffic. The glycosphingolipid and cholesterol-enriched plasma membrane domains that contain caveolae are also enriched for class I molecules, relative to whole plasma membrane. Nevertheless, although class I molecules bind SV40, they do not enter with SV40, nor do they enter spontaneously into uninfected SV40 host cells. Instead, they are shed from the cell surface by the activity of a metalloprotease. These results imply the existence of a putative secondary receptor for SV40 that might mediate SV40 entry. It is not yet clear whether class I molecules are active in transmitting the SV40 signal. Monoclonal antibodies against class I molecules also induce a signal in the SV40 host cells. However, the antibody-induced signal is mediated by mitogen-activated protein kinase (MAP kinase), whereas the SV40 signal is independent of MAP kinase.

  15. Characterization of structural features controlling the receptiveness of empty class II MHC molecules.

    Directory of Open Access Journals (Sweden)

    Bernd Rupp

    Full Text Available MHC class II molecules (MHC II play a pivotal role in the cell-surface presentation of antigens for surveillance by T cells. Antigen loading takes place inside the cell in endosomal compartments and loss of the peptide ligand rapidly leads to the formation of a non-receptive state of the MHC molecule. Non-receptiveness hinders the efficient loading of new antigens onto the empty MHC II. However, the mechanisms driving the formation of the peptide inaccessible state are not well understood. Here, a combined approach of experimental site-directed mutagenesis and computational modeling is used to reveal structural features underlying "non-receptiveness." Molecular dynamics simulations of the human MHC II HLA-DR1 suggest a straightening of the α-helix of the β1 domain during the transition from the open to the non-receptive state. The movement is mostly confined to a hinge region conserved in all known MHC molecules. This shift causes a narrowing of the two helices flanking the binding site and results in a closure, which is further stabilized by the formation of a critical hydrogen bond between residues αQ9 and βN82. Mutagenesis experiments confirmed that replacement of either one of the two residues by alanine renders the protein highly susceptible. Notably, loading enhancement was also observed when the mutated MHC II molecules were expressed on the surface of fibroblast cells. Altogether, structural features underlying the non-receptive state of empty HLA-DR1 identified by theoretical means and experiments revealed highly conserved residues critically involved in the receptiveness of MHC II. The atomic details of rearrangements of the peptide-binding groove upon peptide loss provide insight into structure and dynamics of empty MHC II molecules and may foster rational approaches to interfere with non-receptiveness. Manipulation of peptide loading efficiency for improved peptide vaccination strategies could be one of the applications profiting

  16. Peptide Immunization Elicits Polyomavirus-Specific MHC Class Ib-Restricted CD8 T Cells in MHC Class Ia Allogeneic Mice

    Science.gov (United States)

    Hofstetter, Amelia R.; Evavold, Brian D.

    2013-01-01

    Abstract Unlike the polymorphic MHC class Ia molecules, MHC class Ib molecules are oligomorphic or nonpolymorphic. We recently discovered a protective CD8 T cell response to mouse polyomavirus (MPyV) in H-2b haplotype mice that is restricted by H2-Q9, a member of the Qa-2 MHC class Ib family. Here, we demonstrate that immunization with a peptide corresponding to a virus capsid-derived peptide presented by Q9 also elicits MHC class Ib-restricted MPyV-specific CD8 T cells in mice of H-2s and H-2g7 strains. These findings support the concept that immunization with a single MHC class Ib-restricted peptide can expand CD8 T cells in MHC class Ia allogeneic hosts. PMID:23374150

  17. Composition of MHC class II-enriched lipid microdomains is modified during maturation of primary dendritic cells.

    Science.gov (United States)

    Setterblad, Niclas; Roucard, Corinne; Bocaccio, Claire; Abastado, Jean-Pierre; Charron, Dominique; Mooney, Nuala

    2003-07-01

    Dendritic cells (DCs) are the most potent antigen presenting cells. Major histocompatibility complex (MHC) class II molecule expression changes with maturation; immature DCs concentrate MHC class II molecules intracellularly, whereas maturation increases surface expression of MHC class II and costimulatory molecules to optimize antigen presentation. Signal transduction via MHC class II molecules localized in lipid microdomains has been described in B lymphocytes and in the THP-1 monocyte cell line. We have characterized MHC class II molecules throughout human DC maturation with particular attention to their localization in lipid-rich microdomains. Only immature DCs expressed empty MHC class II molecules, and maturation increased the level of peptide-bound heterodimers. Ligand binding to surface human leukocyte antigen (HLA)-DR induced rapid internalization in immature DCs. The proportion of cell-surface detergent-insoluble glycosphingolipid-enriched microdomain-clustered HLA-DR was higher in immature DCs despite the higher surface expression of HLA-DR in mature DCs. Constituents of HLA-DR containing microdomains included the src kinase Lyn and the cytoskeletal protein tubulin in immature DCs. Maturation modified the composition of the HLA-DR-containing microdomains to include protein kinase C (PKC)-delta, Lyn, and the cytoskeletal protein actin, accompanied by the loss of tubulin. Signaling via HLA-DR redistributed HLA-DR and -DM and PKC-delta as well as enriching the actin content of mature DC microdomains. The increased expression of HLA-DR as a result of DC maturation was therefore accompanied by modification of the spatial organization of HLA-DR. Such regulation could contribute to the distinct responses induced by ligand binding to MHC class II molecules in immature versus mature DCs.

  18. MHC Class II and Non-MHC Class II Genes Differentially Influence Humoral Immunity to Bacillus anthracis Lethal Factor and Protective Antigen

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    Judith A. James

    2012-12-01

    Full Text Available Anthrax Lethal Toxin consists of Protective Antigen (PA and Lethal Factor (LF, and current vaccination strategies focus on eliciting antibodies to PA. In human vaccination, the response to PA can vary greatly, and the response is often directed toward non-neutralizing epitopes. Variable vaccine responses have been shown to be due in part to genetic differences in individuals, with both MHC class II and other genes playing roles. Here, we investigated the relative contribution of MHC class II versus non-MHC class II genes in the humoral response to PA and LF immunization using three immunized strains of inbred mice: A/J (H-2k at the MHC class II locus, B6 (H-2b, and B6.H2k (H-2k. IgG antibody titers to LF were controlled primarily by the MHC class II locus, whereas IgG titers to PA were strongly influenced by the non-MHC class II genetic background. Conversely, the humoral fine specificity of reactivity to LF appeared to be controlled primarily through non-MHC class II genes, while the specificity of reactivity to PA was more dependent on MHC class II. Common epitopes, reactive in all strains, occurred in both LF and PA responses. These results demonstrate that MHC class II differentially influences humoral immune responses to LF and PA.

  19. Regulation of MHC Class II-Peptide Complex Expression by Ubiquitination

    Directory of Open Access Journals (Sweden)

    Kyung Jin eCho

    2013-11-01

    Full Text Available MHC class II (MHC-II molecules are present on antigen presenting cells (APCs and these molecules function by binding antigenic peptides and presenting these peptides to antigen-specific CD4+ T cells. APCs continuously generate and degrade MHC-II molecules, and ubiquitination of MHC-II has recently been shown to be a key regulator of MHC-II expression in dendritic cells (DCs. In this mini-review we will examine the mechanism by which the E3 ubiquitin ligase March-I regulates MHC-II expression on APCs and will discuss the functional consequences of altering MHC-II ubiquitination.

  20. Improved prediction of MHC class I and class II epitopes using a novel Gibbs sampling approach

    DEFF Research Database (Denmark)

    Nielsen, Morten; Lundegaard, Claus; Worning, Peder;

    2004-01-01

    binding peptides and to guiding the process of rational vaccine design. Results: We apply the motif sampler method to the complex problem of MHC class II binding. The input to the method is amino acid peptide sequences extracted from the public databases of SYFPEITHI and MHCPEP and known to bind......Prediction of which peptides will bind a specific major histocompatibility complex (MHC) constitutes an important step in identifying potential T-cell epitopes suitable as vaccine candidates. MHC class II binding peptides have a broad length distribution complicating such predictions. Thus...

  1. Ligation of MHC class I and class II molecules can lead to heterologous desensitization of signal transduction pathways that regulate homotypic adhesion in human lymphocytes.

    Science.gov (United States)

    Wagner, N; Engel, P; Vega, M; Tedder, T F

    1994-06-01

    Engagement of lymphocyte MHC class I and class II Ags activates an array of intracellular signal transduction pathways that up-regulates the activity of cell-surface adhesion receptors, resulting in homotypic cell-cell aggregation. In this study, engagement of MHC class I and class II molecules with specific mAbs was shown to also inhibit lymphocyte homotypic adhesion. Two mAbs reactive with class II Ag, homotypic adhesion blocking mAb (HAB)-2, and HAB-3, and one mAb reactive with class I Ag, HAB-4, were generated that inhibited homotypic adhesion of activated lymphocytes and B and T cell lines at concentrations as low as 0.1 microgram/ml. Binding of these mAbs resulted in heterologous desensitization of other surface signal transduction molecules as homotypic adhesion induced through class I, class II, CD19, CD20, CD39, CD40, Leu-13, and PMA was also inhibited. The spontaneous adhesion exhibited by some cell lines was also abrogated by binding of these mAbs. Abs that either induced, blocked, or had no effect on adhesion bound to distinct epitopes on class I, whereas the anti-class II mAbs recognized either distinct or overlapping epitopes. Thus, engagement of distinct epitopes on MHC molecules can result in homologous or heterologous desensitization of cell-surface signaling molecules. The induction or inhibition of homotypic adhesion through class I molecules did not require the presence of the cytoplasmic domain, as deletion of this portion of the class I molecule had no effect. In contrast, the transmembrane region was essential for signal transduction as the mAbs binding to a chimeric molecule in which the transmembrane and cytoplasmic domains of class I were exchanged with those of the HB15 molecule did not induce or inhibit homotypic adhesion. Although this report is the first demonstration that homotypic adhesion can be influenced in a negative manner through MHC molecules, these findings demonstrate a considerable level of cross-talk between MHC molecules

  2. Tapasin-related protein TAPBPR is an additional component of the MHC class I presentation pathway

    DEFF Research Database (Denmark)

    Boyle, Louise H; Hermann, Clemens; Boname, Jessica M;

    2013-01-01

    Tapasin is an integral component of the peptide-loading complex (PLC) important for efficient peptide loading onto MHC class I molecules. We investigated the function of the tapasin-related protein, TAPBPR. Like tapasin, TAPBPR is widely expressed, IFN-γ-inducible, and binds to MHC class I coupled...... with β2-microglobulin in the endoplasmic reticulum. In contrast to tapasin, TAPBPR does not bind ERp57 or calreticulin and is not an integral component of the PLC. β2-microglobulin is essential for the association between TAPBPR and MHC class I. However, the association between TAPBPR and MHC class I...... occurs in the absence of a functional PLC, suggesting peptide is not required. Expression of TAPBPR decreases the rate of MHC class I maturation through the secretory pathway and prolongs the association of MHC class I on the PLC. The TAPBPR:MHC class I complex trafficks through the Golgi apparatus...

  3. IFN-γ-induced increase in the mobility of MHC class II compartments in astrocytes depends on intermediate filaments

    Directory of Open Access Journals (Sweden)

    Vardjan Nina

    2012-06-01

    Full Text Available Abstract Background In immune-mediated diseases of the central nervous system, astrocytes exposed to interferon-γ (IFN-γ can express major histocompatibility complex (MHC class II molecules and antigens on their surface. MHC class II molecules are thought to be delivered to the cell surface by membrane-bound vesicles. However, the characteristics and dynamics of this vesicular traffic are unclear, particularly in reactive astrocytes, which overexpress intermediate filament (IF proteins that may affect trafficking. The aim of this study was to determine the mobility of MHC class II vesicles in wild-type (WT astrocytes and in astrocytes devoid of IFs. Methods The identity of MHC class II compartments in WT and IF-deficient astrocytes 48 h after IFN-γ activation was determined immunocytochemically by using confocal microscopy. Time-lapse confocal imaging and Alexa Fluor546-dextran labeling of late endosomes/lysosomes in IFN-γ treated cells was used to characterize the motion of MHC class II vesicles. The mobility of vesicles was analyzed using ParticleTR software. Results Confocal imaging of primary cultures of WT and IF-deficient astrocytes revealed IFN-γ induced MHC class II expression in late endosomes/lysosomes, which were specifically labeled with Alexa Fluor546-conjugated dextran. Live imaging revealed faster movement of dextran-positive vesicles in IFN-γ-treated than in untreated astrocytes. Vesicle mobility was lower in IFN-γ-treated IF-deficient astrocytes than in WT astrocytes. Thus, the IFN-γ-induced increase in the mobility of MHC class II compartments is IF-dependent. Conclusions Since reactivity of astrocytes is a hallmark of many CNS pathologies, it is likely that the up-regulation of IFs under such conditions allows a faster and therefore a more efficient delivery of MHC class II molecules to the cell surface. In vivo, such regulatory mechanisms may enable antigen-presenting reactive astrocytes to respond rapidly and in a

  4. Force measurements of TCR/pMHC recognition at T cell surface.

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    Pierre-Henri Puech

    Full Text Available The rupture forces and adhesion frequencies of single recognition complexes between an affinity selected peptide/MHC complex and a TCR at a murine hybridoma surface were measured using Atomic Force Microscopy. When the CD8 coreceptor is absent, the adhesion frequency depends on the nature of the peptide but the rupture force does not. When CD8 is present, no effect of the nature of the peptide is observed. CD8 is proposed to act as a time and distance lock, enabling the shorter TCR molecule to bridge the pMHC and have time to finely read the peptide. Ultimately, such experiments could help the dissection of the sequential steps by which the TCR reads the peptide/MHC complex in order to control T cell activation.

  5. Force-Regulated In Situ TCR-Peptide-Bound MHC Class II Kinetics Determine Functions of CD4+ T Cells.

    Science.gov (United States)

    Hong, Jinsung; Persaud, Stephen P; Horvath, Stephen; Allen, Paul M; Evavold, Brian D; Zhu, Cheng

    2015-10-15

    We have recently shown that two-dimensional (2D) and force-regulated kinetics of TCR-peptide-bound MHC class I (pMHC-I) interactions predict responses of CD8(+) T cells. To test whether these findings are applicable to CD4(+) T cells, we analyzed the in situ 3.L2 TCR-pMHC-II interactions for a well-characterized panel of altered peptide ligands on the T cell surface using the adhesion frequency assay with a micropipette and the thermal fluctuation and force-clamp assays with a biomembrane force probe. We found that the 2D effective TCR-pMHC-II affinity and off-rate correlate with, but better predict the T cell response than, the corresponding measurements with the surface plasmon resonance in three dimensions. The 2D affinity of the CD4 for MHC-II was very low, approaching the detection limit, making it one to two orders of magnitude lower than the affinity of CD8 for MHC-I. In addition, the signal-dependent cooperation between TCR and coreceptor for pMHC binding previously observed for CD8 was not observed for CD4. Interestingly, force elicited TCR-pMHC-II catch-slip bonds for agonists but slip-only bonds for antagonists, thereby amplifying the power of discrimination between altered peptide ligands. These results show that the force-regulated 2D binding kinetics of the 3.L2 TCR for pMHC-II determine functions of CD4(+) T cells. PMID:26336148

  6. MHC class II B diversity in blue tits : A preliminary study

    NARCIS (Netherlands)

    Rivero-de Aguilar, Juan; Schut, Elske; Merino, Santiago; Martinez, Javier; Komdeur, Jan; Westerdahl, Helena

    2013-01-01

    In this study, we partly characterize major histocompatibility complex (MHC) class II B in the blue tit (Cyanistes caeruleus). A total of 22 individuals from three different European locations: Spain, The Netherlands, and Sweden were screened for MHC allelic diversity. The MHC genes were investigate

  7. CITA/NLRC5: A critical transcriptional regulator of MHC class I gene expression.

    Science.gov (United States)

    Downs, Isaac; Vijayan, Saptha; Sidiq, Tabasum; Kobayashi, Koichi S

    2016-07-01

    Major histocompatibility complex (MHC) class I and class II molecules play essential roles in the development and activation of the human adaptive immune system. An NLR protein, CIITA (MHC class II transactivator) has been recognized as a master regulator of MHC class II gene expression, albeit knowledge about the regulatory mechanism of MHC class I gene expression had been limited. Recently identified MHC class I transactivator (CITA), or NLRC5, also belongs to the NLR protein family and constitutes a critical regulator for the transcriptional activation of MHC class I genes. In addition to MHC class I genes, CITA/NLRC5 induces the expression of β2 -microglobulin, TAP1 and LMP2, essential components of the MHC class I antigen presentation pathway. Therefore, CITA/NLRC5 and CIITA are transcriptional regulators that orchestrate the concerted expression of critical components in the MHC class I and class II pathways, respectively. © 2016 BioFactors, 42(4):349-357, 2016. PMID:27087581

  8. Us3 kinase encoded by herpes simplex virus 1 mediates downregulation of cell surface major histocompatibility complex class I and evasion of CD8+ T cells.

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    Takahiko Imai

    Full Text Available Detection and elimination of virus-infected cells by CD8(+ cytotoxic T lymphocytes (CTLs depends on recognition of virus-derived peptides presented by major histocompatibility complex class I (MHC-I molecules on the surface of infected cells. In the present study, we showed that inactivation of the activity of viral kinase Us3 encoded by herpes simplex virus 1 (HSV-1, the etiologic agent of several human diseases and a member of the alphaherpesvirinae, significantly increased cell surface expression of MHC-I, thereby augmenting CTL recognition of infected cells in vitro. Overexpression of Us3 by itself had no effect on cell surface expression of MHC-I and Us3 was not able to phosphorylate MHC-I in vitro, suggesting that Us3 indirectly downregulated cell surface expression of MHC-I in infected cells. We also showed that inactivation of Us3 kinase activity induced significantly more HSV-1-specific CD8(+ T cells in mice. Interestingly, depletion of CD8(+ T cells in mice significantly increased replication of a recombinant virus encoding a kinase-dead mutant of Us3, but had no effect on replication of a recombinant virus in which the kinase-dead mutation was repaired. These results indicated that Us3 kinase activity is required for efficient downregulation of cell surface expression of MHC-I and mediates evasion of HSV-1-specific CD8(+ T cells. Our results also raised the possibility that evasion of HSV-1-specific CD8(+ T cells by HSV-1 Us3-mediated inhibition of MHC-I antigen presentation might in part contribute to viral replication in vivo.

  9. Automated benchmarking of peptide-MHC class I binding predictions

    DEFF Research Database (Denmark)

    Trolle, Thomas; Metushi, Imir G.; Greenbaum, Jason;

    2015-01-01

    Motivation: Numerous in silico methods predicting peptide binding to major histocompatibility complex (MHC) class I molecules have been developed over the last decades. However, the multitude of available prediction tools makes it non-trivial for the end-user to select which tool to use for a given...... the public access to frequent, up-to-date performance evaluations of all participating tools. To overcome potential selection bias in the data included in the IEDB, a strategy was implemented that suggests a set of peptides for which different prediction methods give divergent predictions as to their binding...

  10. Epstein-Barr virus infection of CR2-transfected epithelial cells reveals the presence of MHC class II on the virion.

    Science.gov (United States)

    Knox, P G; Young, L S

    1995-10-20

    Epithelial cell lines transfected with the Epstein-Barr virus (EBV) receptor CR2 are susceptible to infection by EBV. Following infection with certain EBV strains we found that these cells became positive for MHC class II. The class II was confirmed as being of viral and not target cell origin by immunostaining with HLA-specific monoclonal antibodies. Electron microscopic immunogold staining confirmed the presence of MHC class II on the surface of the virion. While some MHC class I was also found on the EB virion, other cell surface molecules were absent. Dual color immunofluorescence and confocal microscopy analysis demonstrated colocalization of class II with EBV-encoded structural proteins (MA and VCA) in infected epithelial cells. However, preincubation of EBV with antibodies against either MHC class I or MHC class II failed to affect either EBV binding or EBV infection. The presence of MHC on the surface of the EB virion may be a consequence of the intracellular pathways through which productive virus exits from the cell and may influence the target cell tropism of EBV. PMID:7483258

  11. MHC class I loci of the Bar-Headed goose (Anser indicus

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    Qinglong Liang

    2010-01-01

    Full Text Available MHC class I proteins mediate functions in anti-pathogen defense. MHC diversity has already been investigated by many studies in model avian species, but here we chose the bar-headed goose, a worldwide migrant bird, as a non-model avian species. Sequences from exons encoding the peptide-binding region (PBR of MHC class I molecules were isolated from liver genomic DNA, to investigate variation in these genes. These are the first MHC class I partial sequences of the bar-headed goose to be reported. A preliminary analysis suggests the presence of at least four MHC class I genes, which share great similarity with those of the goose and duck. A phylogenetic analysis of bar-headed goose, goose and duck MHC class I sequences using the NJ method supports the idea that they all cluster within the anseriforms clade.

  12. Identification of MHC class II restricted T‐cell‐mediated reactivity against MHC class I binding Mycobacterium tuberculosis peptides

    DEFF Research Database (Denmark)

    Wang, Mingjun; Tang, Sheila Tuyet; Stryhn, Anette;

    2011-01-01

    Major histocompatibility complex (MHC) class I restricted cytotoxic T lymphocytes (CTL) are known to play an important role in the control of Mycobacterium tuberculosis infection so identification of CTL epitopes from M. tuberculosis is of importance for the development of effective peptide....... The antigenicity of a total of 157 peptides with measured affinity for HLA‐I molecules of KD ≤ 500 nm were evaluated using peripheral blood T cells from strongly purified protein derivative reactive healthy donors. Of the 157 peptides, eight peptides (5%) were found to induce T‐cell responses. As judged from...

  13. Contrasting evolutionary histories of MHC class I and class II loci in grouse—Effects of selection and gene conversion

    Science.gov (United States)

    Minias, Piotr; Bateson, Zachary W; Whittingham, Linda A; Johnson, Jeff A.; Oyler-McCance, Sara J.; Dunn, Peter O

    2016-01-01

    Genes of the major histocompatibility complex (MHC) encode receptor molecules that are responsible for recognition of intracellular and extracellular pathogens (class I and class II genes, respectively) in vertebrates. Given the different roles of class I and II MHC genes, one might expect the strength of selection to differ between these two classes. Different selective pressures may also promote different rates of gene conversion at each class. Despite these predictions, surprisingly few studies have looked at differences between class I and II genes in terms of both selection and gene conversion. Here, we investigated the molecular evolution of MHC class I and II genes in five closely related species of prairie grouse (Centrocercus and Tympanuchus) that possess one class I and two class II loci. We found striking differences in the strength of balancing selection acting on MHC class I versus class II genes. More than half of the putative antigen-binding sites (ABS) of class II were under positive or episodic diversifying selection, compared with only 10% at class I. We also found that gene conversion had a stronger role in shaping the evolution of MHC class II than class I. Overall, the combination of strong positive (balancing) selection and frequent gene conversion has maintained higher diversity of MHC class II than class I in prairie grouse. This is one of the first studies clearly demonstrating that macroevolutionary mechanisms can act differently on genes involved in the immune response against intracellular and extracellular pathogens.

  14. Modes of salmonid MHC class I and II evolution differ from the primate paradigm

    NARCIS (Netherlands)

    Shum, B.P.; Guethlein, L.; Flodin, L.R.; Adkison, M.A.; Hedrick, R.P.; Nehring, R.B.; Stet, R.J.M.; Secombes, C.; Parham, P.

    2001-01-01

    Rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta) represent two salmonid genera separated for 15-20 million years. cDNA sequences were determined for the classical MHC class I heavy chain gene UBA and the MHC class II β-chain gene DAB from 15 rainbow and 10 brown trout. Both genes a

  15. pH dependence of MHC class I-restricted peptide presentation

    DEFF Research Database (Denmark)

    Stryhn, A; Pedersen, L O; Romme, T;

    1996-01-01

    The function of MHC class I molecules is to bind and present antigenic peptides to cytotoxic T cells. Here, we report that class I-restricted peptide presentation is strongly pH dependent. The presentation of some peptides was enhanced at acidic pH, whereas the presentation of others was inhibited....... Biochemical peptide-MHC class I binding assays demonstrated that peptide-MHC class I complexes are more stable at neutral pH than at acidic pH. We suggest that acid-dependent peptide dissociation can generate empty class I molecules and that the resulting binding potential can be exploited by a subset...

  16. Chemotherapeutics and radiation stimulate MHC class I expression through elevated interferon-beta signaling in breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Shan Wan

    Full Text Available Low doses of anticancer drugs have been shown to enhance antitumor immune response and increase the efficacy of immunotherapy. The molecular basis for such effects remains elusive, although selective depletion of T regulatory cells has been demonstrated. In the current studies, we demonstrate that topotecan (TPT, a topoisomerase I-targeting drug with a well-defined mechanism of action, stimulates major histocompatibility complex class I (MHC I expression in breast cancer cells through elevated expression/secretion of interferon-β (IFN-β and activation of type I IFN signaling. First, we show that TPT treatment elevates the expression of both total and cell-surface MHC I in breast cancer cells. Second, conditioned media from TPT-treated breast cancer ZR-75-1 cells induce elevated expression of cell-surface MHC I in drug-naïve recipient cells, suggesting the involvement of cytokines and/or other secreted molecules. Consistently, TPT-treated cells exhibit elevated expression of multiple cytokines such as IFN-β, TNF-α, IL-6 and IL-8. Third, either knocking down the type I interferon receptor subunit 1 (IFNAR1 or addition of neutralizing antibody against IFN-β results in reduced MHC I expression in TPT-treated cells. Together, these results suggest that TPT induces increased IFN-β autocrine/paracrine signaling through type I IFN receptor, resulting in the elevated MHC I expression in tumor cells. Studies have also demonstrated that other chemotherapeutic agents (e.g. etoposide, cisplatin, paclitaxel and vinblastine similarly induce increased IFN-β secretion and elevated MHC I expression. In addition, conditioned media from γ-irradiated donor cells are shown to induce IFN-β-dependent MHC I expression in unirradiated recipient cells. In the aggregate, our results suggest that many cancer therapeutics induce elevated tumor antigen presentation through MHC I, which could represent a common mechanism for enhanced antitumor immune response through

  17. Improved pan-specific MHC class I peptide-binding predictions using a novel representation of the MHC-binding cleft environment

    DEFF Research Database (Denmark)

    Carrasco Pro, S.; Zimic, M.; Nielsen, Morten

    2014-01-01

    Major histocompatibility complex (MHC) molecules play a key role in cell-mediated immune responses presenting bounded peptides for recognition by the immune system cells. Several in silico methods have been developed to predict the binding affinity of a given peptide to a specific MHC molecule. One...... of the current state-of-the-art methods for MHC class I is NetMHCpan, which has a core ingredient for the representation of the MHC class I molecule using a pseudo-sequence representation of the binding cleft amino acid environment. New and large MHC-peptide-binding data sets are constantly being made available......, and also new structures of MHC class I molecules with a bound peptide have been published. In order to test if the NetMHCpan method can be improved by integrating this novel information, we created new pseudo-sequence definitions for the MHC-binding cleft environment from sequence and structural analyses...

  18. T cells induce extended class II MHC compartments in dendritic cells in a Toll-like receptor-dependent manner.

    Science.gov (United States)

    Boes, Marianne; Bertho, Nicolas; Cerny, Jan; Op den Brouw, Marjolein; Kirchhausen, Tomas; Ploegh, Hidde

    2003-10-15

    Interaction of Ag-loaded dendritic cells with Ag-specific CD4 T cells induces the formation of long tubular class II MHC-positive compartments that polarize toward the T cell. We show involvement of a Toll-like receptor-mediated signal in this unusual form of intracellular class II MHC trafficking. First, wild-type dendritic cells loaded with LPS-free Ag failed to show formation of class II-positive tubules upon Ag-specific T cell engagement, but did so upon supplementation of the Ag with low concentrations of LPS. Second, Ag-loaded myeloid differentiation factor 88 -deficient dendritic cells failed to form these tubules upon interaction with T cells, regardless of the presence of LPS. Finally, inclusion of a cell-permeable peptide that blocks TNFR-associated factor 6 function, downstream of myeloid differentiation factor 88, blocked T cell-dependent tubulation. A Toll-like receptor-dependent signal is thus required to allow Ag-loaded dendritic cells to respond to T cell contact by formation of extended endosomal compartments. This activation does not result in massive translocation of class II MHC molecules to the cell surface.

  19. Transport of Streptococcus pneumoniae capsular polysaccharide in MHC Class II tubules.

    Directory of Open Access Journals (Sweden)

    Tom Li Stephen

    2007-03-01

    Full Text Available Bacterial capsular polysaccharides are virulence factors and are considered T cell-independent antigens. However, the capsular polysaccharide Sp1 from Streptococcus pneumoniae serotype 1 has been shown to activate CD4(+ T cells in a major histocompatibility complex (MHC class II-dependent manner. The mechanism of carbohydrate presentation to CD4(+ T cells is unknown. We show in live murine dendritic cells (DCs that Sp1 translocates from lysosomal compartments to the plasma membrane in MHCII-positive tubules. Sp1 cell surface presentation results in reduction of self-peptide presentation without alteration of the MHCII self peptide repertoire. In DM-deficient mice, retrograde transport of Sp1/MHCII complexes resulting in T cell-dependent immune responses to the polysaccharide in vitro and in vivo is significantly reduced. The results demonstrate the capacity of a bacterial capsular polysaccharide antigen to use DC tubules as a vehicle for its transport as an MHCII/saccharide complex to the cell surface for the induction of T cell activation. Furthermore, retrograde transport requires the functional role of DM in self peptide-carbohydrate exchange. These observations open new opportunities for the design of vaccines against microbial encapsulated pathogens.

  20. Transcriptional profiling of MHC class I genes in rainbow trout infected with infectious hematopoietic necrosis virus

    Science.gov (United States)

    Landis, E.D.; Purcell, M.K.; Thorgaard, G.H.; Wheeler, P.A.; Hansen, J.D.

    2008-01-01

    Major histocompatibility complex (MHC) molecules are important mediators of cell-mediated immunity in vertebrates. MHC class IA molecules are important for host anti-viral immunity as they present intracellular antigens and regulate natural killer cell (NK) activity. MHC class Ib molecules on the other hand are less understood and have demonstrated diverse immune and non-immune functions in mammals. Rainbow trout possess a single classical MHC IA locus (Onmy-UBA) that is believed to function similar to that of mammalian MHC class Ia. Numerous MHC class Ib genes with undetermined functions have also been described in trout. Here we utilize quantitative reverse transcriptase PCR (qRT-PCR) techniques to survey the levels of basal and inducible transcription for selected trout MHC class Ib genes, sIgM and sentinels of IFN induction in response to viral infection. Basal transcription of all the class Ib genes examined in this study was lower than Onmy-UBA in nai??ve fish. UBA, along with all of the non-classical genes were induced in fish infected with virus but not in control fish. Our results support a non-classical designation for the majority of the class IB genes surveyed in this study based upon expression levels while also indicating that they may play an important role in anti-viral immunity in trout.

  1. Towards universal structure-based prediction of class II MHC epitopes for diverse allotypes.

    Directory of Open Access Journals (Sweden)

    Andrew J Bordner

    Full Text Available The binding of peptide fragments of antigens to class II MHC proteins is a crucial step in initiating a helper T cell immune response. The discovery of these peptide epitopes is important for understanding the normal immune response and its misregulation in autoimmunity and allergies and also for vaccine design. In spite of their biomedical importance, the high diversity of class II MHC proteins combined with the large number of possible peptide sequences make comprehensive experimental determination of epitopes for all MHC allotypes infeasible. Computational methods can address this need by predicting epitopes for a particular MHC allotype. We present a structure-based method for predicting class II epitopes that combines molecular mechanics docking of a fully flexible peptide into the MHC binding cleft followed by binding affinity prediction using a machine learning classifier trained on interaction energy components calculated from the docking solution. Although the primary advantage of structure-based prediction methods over the commonly employed sequence-based methods is their applicability to essentially any MHC allotype, this has not yet been convincingly demonstrated. In order to test the transferability of the prediction method to different MHC proteins, we trained the scoring method on binding data for DRB1*0101 and used it to make predictions for multiple MHC allotypes with distinct peptide binding specificities including representatives from the other human class II MHC loci, HLA-DP and HLA-DQ, as well as for two murine allotypes. The results showed that the prediction method was able to achieve significant discrimination between epitope and non-epitope peptides for all MHC allotypes examined, based on AUC values in the range 0.632-0.821. We also discuss how accounting for peptide binding in multiple registers to class II MHC largely explains the systematically worse performance of prediction methods for class II MHC compared with

  2. Towards universal structure-based prediction of class II MHC epitopes for diverse allotypes.

    Science.gov (United States)

    Bordner, Andrew J

    2010-01-01

    The binding of peptide fragments of antigens to class II MHC proteins is a crucial step in initiating a helper T cell immune response. The discovery of these peptide epitopes is important for understanding the normal immune response and its misregulation in autoimmunity and allergies and also for vaccine design. In spite of their biomedical importance, the high diversity of class II MHC proteins combined with the large number of possible peptide sequences make comprehensive experimental determination of epitopes for all MHC allotypes infeasible. Computational methods can address this need by predicting epitopes for a particular MHC allotype. We present a structure-based method for predicting class II epitopes that combines molecular mechanics docking of a fully flexible peptide into the MHC binding cleft followed by binding affinity prediction using a machine learning classifier trained on interaction energy components calculated from the docking solution. Although the primary advantage of structure-based prediction methods over the commonly employed sequence-based methods is their applicability to essentially any MHC allotype, this has not yet been convincingly demonstrated. In order to test the transferability of the prediction method to different MHC proteins, we trained the scoring method on binding data for DRB1*0101 and used it to make predictions for multiple MHC allotypes with distinct peptide binding specificities including representatives from the other human class II MHC loci, HLA-DP and HLA-DQ, as well as for two murine allotypes. The results showed that the prediction method was able to achieve significant discrimination between epitope and non-epitope peptides for all MHC allotypes examined, based on AUC values in the range 0.632-0.821. We also discuss how accounting for peptide binding in multiple registers to class II MHC largely explains the systematically worse performance of prediction methods for class II MHC compared with those for class I MHC

  3. The cytoplasmic and the transmembrane domains are not sufficient for class I MHC signal transduction.

    Science.gov (United States)

    Gur, H; Geppert, T D; Wacholtz, M C; Lipsky, P E

    1999-02-01

    Class I MHC molecules deliver activation signals to T cells. To analyze the role of the cytoplasmic and the transmembrane (TM) domains of class I MHC molecules in T cell activation, Jurkat cells were transfected with genes for truncated class I MHC molecules which had only four intracytoplasmic amino acids and no potential phosphorylation sites or native molecules or both. Cross-linking either the native or the truncated molecules induced IL-2 production even under limiting stimulation conditions of low engagement of the stimulating mAb. Moreover, direct comparison of transfected truncated and native class I MHC molecules expressed on the same cell revealed significant stimulation induced by cross-linking the truncated molecules, despite low expression. In addition, truncated class I MHC molecules were as able to synergize with CD3, CD2, or CD28 initiated IL-2 production as native molecules. In further experiments, hybrid constructs made of the extracellular portion of the murine CD8 alpha chain and of the TM and the intracytoplasmic domains of H-2Kk class I MHC molecule were transfected into Jurkat T cells. The expression of the transfected hybrid molecules was comparable to that of the native HLA-B7 molecules. Cross-linking the intact monomorphic HLA-A,B,C epitope or the polymorphic HLA-B7 epitope induced IL-2 production upon costimulation with PMA. In contrast, cross-linking the hybrid molecules generated neither an increase in intracellular calcium concentration ([Ca2+]i) nor stimulated IL-2 production. By contrast, cross-linking intact murine class I MHC molecules induced [Ca2+]i, signal and IL-2 production in transfected Jurkat cells. The data therefore indicate that unlike many other signaling molecules, signaling via class I MHC molecules does not involve the cytoplasmic and the TM portions of the molecule, but rather class I MHC signal transduction is likely to be mediated by the extracellular domain of the molecule.

  4. Neuronal MHC Class I Expression Is Regulated by Activity Driven Calcium Signaling.

    Directory of Open Access Journals (Sweden)

    Dan Lv

    Full Text Available MHC class I (MHC-I molecules are important components of the immune system. Recently MHC-I have been reported to also play important roles in brain development and synaptic plasticity. In this study, we examine the molecular mechanism(s underlying activity-dependent MHC-I expression using hippocampal neurons. Here we report that neuronal expression level of MHC-I is dynamically regulated during hippocampal development after birth in vivo. Kainic acid (KA treatment significantly increases the expression of MHC-I in cultured hippocampal neurons in vitro, suggesting that MHC-I expression is regulated by neuronal activity. In addition, KA stimulation decreased the expression of pre- and post-synaptic proteins. This down-regulation is prevented by addition of an MHC-I antibody to KA treated neurons. Further studies demonstrate that calcium-dependent protein kinase C (PKC is important in relaying KA simulation activation signals to up-regulated MHC-I expression. This signaling cascade relies on activation of the MAPK pathway, which leads to increased phosphorylation of CREB and NF-κB p65 while also enhancing the expression of IRF-1. Together, these results suggest that expression of MHC-I in hippocampal neurons is driven by Ca2+ regulated activation of the MAPK signaling transduction cascade.

  5. Pan-specific MHC class I predictors: A benchmark of HLA class I pan-specific prediction methods

    DEFF Research Database (Denmark)

    Zhang, Hao; Lundegaard, Claus; Nielsen, Morten

    2009-01-01

    emerging pathogens. Methods have recently been published that are able to predict peptide binding to any human MHC class I molecule. In contrast to conventional allele-specific methods, these methods do allow for extrapolation to un-characterized MHC molecules. These pan-specific HLA predictors have...... not previously been compared using independent evaluation sets. Results: A diverse set of quantitative peptide binding affinity measurements was collected from IEDB, together with a large set of HLA class I ligands from the SYFPEITHI database. Based on these data sets, three different pan-specific HLA web......-accessible predictors NetMHCpan, Adaptive-Double-Threading (ADT), and KISS were evaluated. The performance of the pan-specific predictors was also compared to a well performing allele-specific MHC class I predictor, NetMHC, as well as a consensus approach integrating the predictions from the NetMHC and Net...

  6. Molecular characterization of MHC class II in the Australian invasive cane toad reveals multiple splice variants.

    Science.gov (United States)

    Lillie, Mette; Cui, Jian; Shine, Richard; Belov, Katherine

    2016-07-01

    The cane toad has gained notoriety for its invasion across the Australian landscape, with significant impacts on the native Australian fauna. The invasion has accelerated over time, with invading cane toads adapted for highly dispersive traits. This, however, has come at the cost of the immune system, with lower investment in some immune functions. To investigate the cane toad's immunogenetics, we characterized four major histocompatibility complex (MHC) class IIA and three MHC class IIB loci. Preliminary observations suggest very low allelic diversity at all loci. We also observed various splice isoforms. One isoform seen at one class IIA and two class IIB loci was missing exon 2, which is essential to peptide binding and presentation. The other isoform, observed at a class IIA locus, is likely to be a soluble MHC product. These results may suggest a significant role of alternative splicing of MHC loci in the Australian cane toad. PMID:27233954

  7. A hybrid approach for predicting promiscuous MHC class I restricted T cell epitopes

    Indian Academy of Sciences (India)

    Manoj Bhasin; G P S Raghava

    2007-01-01

    In the present study, a systematic attempt has been made to develop an accurate method for predicting MHC class I restricted T cell epitopes for a large number of MHC class I alleles. Initially, a quantitative matrix (QM)-based method was developed for 47 MHC class I alleles having at least 15 binders. A secondary artificial neural network (ANN)-based method was developed for 30 out of 47 MHC alleles having a minimum of 40 binders. Combination of these ANN- and QM-based prediction methods for 30 alleles improved the accuracy of prediction by 6% compared to each individual method. Average accuracy of hybrid method for 30 MHC alleles is 92.8%. This method also allows prediction of binders for 20 additional alleles using QM that has been reported in the literature, thus allowing prediction for 67 MHC class I alleles. The performance of the method was evaluated using jack-knife validation test. The performance of the methods was also evaluated on blind or independent data. Comparison of our method with existing MHC binder prediction methods for alleles studied by both methods shows that our method is superior to other existing methods. This method also identifies proteasomal cleavage sites in antigen sequences by implementing the matrices described earlier. Thus, the method that we discover allows the identification of MHC class I binders (peptides binding with many MHC alleles) having proteasomal cleavage site at C-terminus. The user-friendly result display format (HTML-II) can assist in locating the promiscuous MHC binding regions from antigen sequence. The method is available on the web at www.imtech.res.in/raghava/nhlapred and its mirror site is available at http://bioinformatics.uams.edu/mirror/nhlapred/.

  8. Limitations of Ab Initio Predictions of Peptide Binding to MHC Class II Molecules

    DEFF Research Database (Denmark)

    Zhang, Hao; Lund, Ole; Nielsen, Morten;

    2010-01-01

    Successful predictions of peptide MHC binding typically require a large set of binding data for the specific MHC molecule that is examined. Structure based prediction methods promise to circumvent this requirement by evaluating the physical contacts a peptide can make with an MHC molecule based...... on the highly conserved 3D structure of peptide:MHC complexes. While several such methods have been described before, most are not publicly available and have not been independently tested for their performance. We here implemented and evaluated three prediction methods for MHC class II molecules: statistical...... methods prediction performance showed that these are significantly better than random, but still substantially lower than the best performing sequence based class II prediction methods available. While the approaches presented here were developed independently, we have chosen to present our results...

  9. Expression and characterization of recombinant single-chain salmon class I MHC fused with ß2-microglobulin with biological activity

    NARCIS (Netherlands)

    Zhao, H.; Stet, R.J.M.; Skjodt, K.; Savelkoul, H.F.J.

    2008-01-01

    Heterodimeric class I major histocompatibility complex (MHC) molecules consist of a putative 45-kDa heavy chain and a 12-kDa ß2-microglobulin (ß2m) light chain. The knowledge about MHC genes in Atlantic salmon accumulated during the last decade has allowed us to generate soluble and stable MHC class

  10. Assembly and characterization of the MHC class I region of the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis).

    Science.gov (United States)

    Ruan, Rui; Wan, Xiao-Ling; Zheng, Yang; Zheng, Jin-Song; Wang, Ding

    2016-01-01

    The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis; YFP) is the sole freshwater subspecies of N. asiaeorientalis and is now critically endangered. Major histocompatibility complex (MHC) is a family of highly polymorphic genes that play an important immunological role in antigen presentation in the vertebrates. Currently, however, little is known about MHC region in the genome of the YFP, which hampers conservation genetics and evolutionary ecology study using MHC genes. In this work, a nucleotide sequence of 774,811 bp covering the YFP MHC class I region was obtained by screening a YFP bacterial artificial chromosome (BAC) library, followed by sequencing and assembly of positive BAC clones. A total of 45 genes were successfully annotated, of which four were MHC class I genes. There are high similarities among the four YFP MHC class I genes (>94%). Divergence in the coding region of the four YFP MHC class I genes is mainly localized to exons 2 and 3, which encode the antigen-binding sites of MHC class I genes. Additionally, comparison of the MHC structure in YFP to those of cattle, sheep, and pig showed that MHC class I genes are located in genome regions with regard to the conserved genes, and the YFP contains the fewest MHC class I genes among these species. This is the first report characterizing a cetacean MHC class I region and describing its organization, which would be valuable for further investigation of adaptation in natural populations of the YFP and other cetaceans. PMID:26585324

  11. Diagnostic value of MHC class I staining in idiopathic inflammatory myopathies.

    NARCIS (Netherlands)

    Pas, J. van der; Hengstman, G.J.D.; Laak, H.J. ter; Borm, G.F.; Engelen, B.G.M. van

    2004-01-01

    BACKGROUND: Identification of mononuclear cellular infiltrates in skeletal muscle tissue is the histological cornerstone of the diagnosis of idiopathic inflammatory myopathy (IIM). However, these infiltrates are not always present. OBJECTIVE: To determine whether MHC class I antigen expression on th

  12. The murine cytomegalovirus immunoevasin gp40 binds MHC class I molecules to retain them in the early secretory pathway.

    Science.gov (United States)

    Janßen, Linda; Ramnarayan, Venkat Raman; Aboelmagd, Mohamed; Iliopoulou, Maro; Hein, Zeynep; Majoul, Irina; Fritzsche, Susanne; Halenius, Anne; Springer, Sebastian

    2016-01-01

    In the presence of the murine cytomegalovirus (mCMV) gp40 (m152) protein, murine major histocompatibility complex (MHC) class I molecules do not reach the cell surface but are retained in an early compartment of the secretory pathway. We find that gp40 does not impair the folding or high-affinity peptide binding of the class I molecules but binds to them, leading to their retention in the endoplasmic reticulum (ER), the ER-Golgi intermediate compartment (ERGIC) and the cis-Golgi, most likely by retrieval from the cis-Golgi to the ER. We identify a sequence in gp40 that is required for both its own retention in the early secretory pathway and for that of class I molecules.

  13. Tolerance to MHC class II disparate allografts through genetic modification of bone marrow

    OpenAIRE

    Jindra, Peter T.; TRIPATHI, SUDIPTA; Tian, Chaorui; Iacomini, John; Bagley, Jessamyn

    2012-01-01

    Induction of molecular chimerism through genetic modification of bone marrow is a powerful tool for the induction of tolerance. Here we demonstrate for the first time that expression of an allogeneic MHC class II gene in autologous bone marrow cells, resulting in a state of molecular chimerism, induces tolerance to MHC class II mismatched skin grafts, a stringent test of transplant tolerance. Reconstitution of recipients with syngeneic bone marrow transduced with retrovirus encoding H-2I-Ab (...

  14. Immunological Functions of the Membrane Proximal Region of MHC Class II Molecules.

    Science.gov (United States)

    Harton, Jonathan; Jin, Lei; Hahn, Amy; Drake, Jim

    2016-01-01

    Major histocompatibility complex (MHC) class II molecules present exogenously derived antigen peptides to CD4 T cells, driving activation of naïve T cells and supporting CD4-driven immune functions. However, MHC class II molecules are not inert protein pedestals that simply bind and present peptides. These molecules also serve as multi-functional signaling molecules delivering activation, differentiation, or death signals (or a combination of these) to B cells, macrophages, as well as MHC class II-expressing T cells and tumor cells. Although multiple proteins are known to associate with MHC class II, interaction with STING (stimulator of interferon genes) and CD79 is essential for signaling. In addition, alternative transmembrane domain pairing between class II α and β chains influences association with membrane lipid sub-domains, impacting both signaling and antigen presentation. In contrast to the membrane-distal region of the class II molecule responsible for peptide binding and T-cell receptor engagement, the membrane-proximal region (composed of the connecting peptide, transmembrane domain, and cytoplasmic tail) mediates these "non-traditional" class II functions. Here, we review the literature on the function of the membrane-proximal region of the MHC class II molecule and discuss the impact of this aspect of class II immunobiology on immune regulation and human disease. PMID:27006762

  15. High-throughput engineering and analysis of peptide binding to class II MHC.

    Science.gov (United States)

    Jiang, Wei; Boder, Eric T

    2010-07-27

    Class II major histocompatibility complex (MHC-II) proteins govern stimulation of adaptive immunity by presenting antigenic peptides to CD4+ T lymphocytes. Many allelic variants of MHC-II exist with implications in peptide presentation and immunity; thus, high-throughput experimental tools for rapid and quantitative analysis of peptide binding to MHC-II are needed. Here, we present an expression system wherein peptide and MHC-II are codisplayed on the surface of yeast in an intracellular association-dependent manner and assayed by flow cytometry. Accordingly, the relative binding of different peptides and/or MHC-II variants can be assayed by genetically manipulating either partner, enabling the application of directed evolution approaches for high-throughput characterization or engineering. We demonstrate the application of this tool to map the side-chain preference for peptides binding to HLA-DR1 and to evolve novel HLA-DR1 mutants with altered peptide-binding specificity.

  16. No evidence for MHC class I-based disassortative mating in a wild population of great tits.

    Science.gov (United States)

    Sepil, I; Radersma, R; Santure, A W; De Cauwer, I; Slate, J; Sheldon, B C

    2015-03-01

    Genes of the major histocompatibility complex (MHC) are regarded as a potentially important target of mate choice due to the fitness benefits that may be conferred to the offspring. According to the complementary genes hypothesis, females mate with MHC dissimilar males to enhance the immunocompetence of their offspring or to avoid inbreeding depression. Here, we investigate whether selection favours a preference for maximally dissimilar or optimally dissimilar MHC class I types, based on MHC genotypes, average amino acid distances and the functional properties of the antigen-binding sites (MHC supertypes); and whether MHC type dissimilarity predicts relatedness between mates in a wild great tit population. In particular, we explore the role that MHC class I plays in female mate choice decisions while controlling for relatedness and spatial population structure, and examine the reproductive fitness consequences of MHC compatibility between mates. We find no evidence for the hypotheses that females select mates on the basis of either maximal or optimal MHC class I dissimilarity. A weak correlation between MHC supertype sharing and relatedness suggests that MHC dissimilarity at functional variants may not provide an effective index of relatedness. Moreover, the reproductive success of pairs did not vary with MHC dissimilarity. Our results provide no support for the suggestion that selection favours, or that mate choice realizes, a preference for complimentary MHC types. PMID:25661713

  17. Premalignant quiescent melanocytic nevi do not express the MHC class I chain-related protein A

    Directory of Open Access Journals (Sweden)

    Mercedes B. Fuertes

    2011-08-01

    Full Text Available The MHC class I chain-related protein A (MICA is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK cells, CD8+ aßTCR and ?dTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-? secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease- induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples as well as in normal skin, benign lesions (seborrheic keratosis, premalignant lesions (actinic keratosis and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.

  18. Premalignant quiescent melanocytic nevi do not express the MHC class I chain-related protein A.

    Science.gov (United States)

    Fuertes, Mercedes B; Rossi, Lucas E; Peralta, Carlos M; Cabrera, Hugo N; Allevato, Miguel A; Zwirner, Norberto W

    2011-01-01

    The MHC class I chain-related protein A (MICA) is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK) cells, CD8+ abTCR and gdTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-g secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease-induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi) remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples) as well as in normal skin, benign lesions (seborrheic keratosis), premalignant lesions (actinic keratosis) and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.

  19. ER stress affects processing of MHC class I-associated peptides

    Directory of Open Access Journals (Sweden)

    Meloche Sylvain

    2009-02-01

    Full Text Available Abstract Background Viral infection and neoplastic transformation trigger endoplasmic reticulum (ER stress. Thus, a large proportion of the cells that must be recognized by the immune system are stressed cells. Cells respond to ER stress by launching the unfolded protein response (UPR. The UPR regulates the two key processes that control major histocompatibility complex class I (MHC I-peptide presentation: protein synthesis and degradation. We therefore asked whether and how the UPR impinges on MHC I-peptide presentation. Results We evaluated the impact of the UPR on global MHC I expression and on presentation of the H2Kb-associated SIINFEKL peptide. EL4 cells stably transfected with vectors coding hen egg lysozyme (HEL-SIINFEKL protein variants were stressed with palmitate or exposed to glucose deprivation. UPR decreased surface expression of MHC I but did not affect MHC I mRNA level nor the total amount of intracellular MHC I proteins. Impaired MHC I-peptide presentation was due mainly to reduced supply of peptides owing to an inhibition of overall protein synthesis. Consequently, generation of H2Kb-SIINFEKL complexes was curtailed during ER stress, illustrating how generation of MHC I peptide ligands is tightly coupled to ongoing protein synthesis. Notably, the UPR-induced decline of MHC I-peptide presentation was more severe when the protein source of peptides was localized in the cytosol than in the ER. This difference was not due to changes in the translation rates of the precursor proteins but to increased stability of the cytosolic protein during ER stress. Conclusion Our results demonstrate that ER stress impairs MHC I-peptide presentation, and that it differentially regulates expression of ER- vs. cytosol-derived peptides. Furthermore, this work illustrates how ER stress, a typical feature of infected and malignant cells, can impinge on cues for adaptive immune recognition.

  20. Nucleotide sequences of chimpanzee MHC class I alleles: evidence for trans-species mode of evolution.

    OpenAIRE

    Mayer, W.E.; Jonker, M; Klein, D; Ivanyi, P; van Seventer, G; Klein, J.

    1988-01-01

    To obtain an insight into the evolutionary origin of the major histocompatibility complex (MHC) class I polymorphism, a cDNA library was prepared from a heterozygous chimpanzee cell line expressing MHC class I molecules crossreacting with allele-specific HLA-A11 antibodies. The library was screened with human class I locus-specific DNA probes, and clones encoding both alleles at the A and B loci have been identified and sequenced. In addition, the sequences of two HLA-A11 subtypes differing b...

  1. MHC Class I Exon 4 in the Multiocellated Racerunners (Eremias multiocellata):Polymorphism, Duplication and Selection

    Institute of Scientific and Technical Information of China (English)

    Xiuyun YUAN; Xiaomao ZENG; Xianguang GUO

    2014-01-01

    The major histocompatibility complex (MHC) is a dynamic genetic region with an essential role in the adaptive immunity of jawed vertebrates. The MHC polymorphism is affected by many processes such as birth-and-death evolution, gene conversion, and concerted evolution. Studies investigating the evolution of MHC class I genes have been biased toward a few particular taxa and model species. However, the investigation of this region in non-avian reptiles is still in its infancy. We present the ifrst characterization of MHC class I genes in a species from the family Lacertidae. We assessed genetic diversity and a role of selection in shaping the diversity of MHC class I exon 4 among 37 individuals of Eremias multiocellata from a population in Lanzhou, China. We generated 67 distinct DNA sequences using cloning and sequencing methods, and identiifed 36 putative functional variants as well as two putative pseudogene-variants. We found the number of variants within an individual varying between two and seven, indicating that there are at least four MHC class I loci in this species. Gene duplication plays a role in increasing copy numbers of MHC genes and allelic diversity in this species. The class I exon 4 sequences are characteristic of low nucleotide diversity. No signal of recombination is detected, but purifying selection is detected inβ2-microglobulin interaction sites and some other silent sites outside of the function-constraint regions. Certain identical alleles are shared by Eremias multiocellata and E. przewalskii and E. brenchleyi, suggesting trans-species polymorphism. The data are compatible with a birth-and-death model of evolution.

  2. Properties of MHC class I presented peptides that enhance immunogenicity.

    Directory of Open Access Journals (Sweden)

    Jorg J A Calis

    2013-10-01

    Full Text Available T-cells have to recognize peptides presented on MHC molecules to be activated and elicit their effector functions. Several studies demonstrate that some peptides are more immunogenic than others and therefore more likely to be T-cell epitopes. We set out to determine which properties cause such differences in immunogenicity. To this end, we collected and analyzed a large set of data describing the immunogenicity of peptides presented on various MHC-I molecules. Two main conclusions could be drawn from this analysis: First, in line with previous observations, we showed that positions P4-6 of a presented peptide are more important for immunogenicity. Second, some amino acids, especially those with large and aromatic side chains, are associated with immunogenicity. This information was combined into a simple model that was used to demonstrate that immunogenicity is, to a certain extent, predictable. This model (made available at http://tools.iedb.org/immunogenicity/ was validated with data from two independent epitope discovery studies. Interestingly, with this model we could show that T-cells are equipped to better recognize viral than human (self peptides. After the past successful elucidation of different steps in the MHC-I presentation pathway, the identification of variables that influence immunogenicity will be an important next step in the investigation of T-cell epitopes and our understanding of cellular immune responses.

  3. Leukocyte Ig-Like Receptors – a model for MHC class I disease associations

    Directory of Open Access Journals (Sweden)

    Rachel Louise Allen

    2016-07-01

    Full Text Available MHC class I (MHC-I polymorphisms are associated with the outcome of some viral infections and autoimmune diseases. MHC-I proteins present antigenic peptides and are recognised by receptors on Natural Killer cells and Cytotoxic T lymphocytes, thus enabling the immune system to detect self-antigens and eliminate targets lacking self or expressing foreign antigens. Recognition of MHC-I, however, extends beyond receptors on cytotoxic leukocytes. Members of the Leukocyte Ig-like receptor (LILR family are expressed on monocytic cells and can recognise both classical and non-classical MHC-I alleles. Despite their relatively broad specificity when compared to the T Cell Receptor or Killer Ig-like Receptors, variations in the strength of LILR binding between different MHC-I alleles have recently been shown to correlate with control of HIV infection. We suggest that LILR recognition may mediate MHC-I disease association in a manner that does not depend on a binary discrimination of self/non-self by cytotoxic cells. Instead, the effects of LILR activity following engagement by MHC-I may represent a degrees of self model, whereby strength of binding to different alleles determines the degree of influence exerted by these receptors on immune cell functions. LILR are expressed by myelomonocytic cells and lymphocytes, extending their influence across antigen presenting cell subsets including dendritic cells, macrophages and B cells. They have been identified as important players in the response to infection, inflammatory diseases and cancer, with recent literature to indicate that MHC-I recognition by these receptors and consequent allelic effects could extend an influence beyond the immune system.

  4. Allelic Polymorphism, Gene Duplication and Balancing Selection of MHC Class IIB Genes in the Omei Treefrog (Rhacophorus omeimontis)

    Institute of Scientific and Technical Information of China (English)

    Li HUANG; Mian ZHAO; Zhenhua LUO; Hua WU

    2016-01-01

    The worldwide declines in amphibian populations have largely been caused by infectious fungi and bacteria. Given that vertebrate immunity against these extracellular pathogens is primarily functioned by the major histocompatibility complex (MHC) class II molecules, the characterization and the evolution of amphibian MHC class II genes have attracted increasing attention. The polymorphism of MHC class II genes was found to be correlated with susceptibility to fungal pathogens in many amphibian species, suggesting the importance of studies on MHC class II genes for amphibians. However, such studies on MHC class II gene evolution have rarely been conducted on amphibians in China. In this study, we chose Omei treefrog (Rhacophorus omeimontis), which lived moist environments easy for breeding bacteria, to study the polymorphism of its MHC class II genes and the underlying evolutionary mechanisms. We amplified the entire MHC class IIB exon 2 sequence in the R. omeimontis using newly designed primers. We detected 102 putative alleles in 146 individuals. The number of alleles per individual ranged from one to seven, indicating that there are at least four loci containing MHC class IIB genes in R. omeimontis. The allelic polymorphism estimated from the 102 alleles in R. omeimontis was not high compared to that estimated in other anuran species. No significant gene recombination was detected in the 102 MHC class IIB exon 2 sequences. In contrast, both gene duplication and balancing selection greatly contributed to the variability in MHC class IIB exon 2 sequences of R. omeimontis. This study lays the groundwork for the future researches to comprehensively analyze the evolution of amphibian MHC genes and to assess the role of MHC gene polymorphisms in resistance against extracellular pathogens for amphibians in China.

  5. The UL41-encoded virion host shutoff (vhs) protein and vhs-independent mechanisms are responsible for down-regulation of MHC class I molecules by bovine herpesvirus 1.

    Science.gov (United States)

    Koppers-Lalic, D; Rijsewijk, F A; Verschuren, S B; van Gaans-Van den Brink, J A; Neisig, A; Ressing, M E; Neefjes, J; Wiertz, E J

    2001-09-01

    The virion host shutoff (vhs) protein of alphaherpesviruses causes a rapid shutoff of host cell protein synthesis. We constructed a bovine herpesvirus 1 (BHV1) deletion mutant in which the putative vhs gene, UL41, has been disrupted. Whereas protein synthesis is inhibited within 3 h after infection with wild-type BHV1, no inhibition was observed after infection with the BHV1(vhs-) deletion mutant. These results indicate that the BHV1 UL41 gene product is both necessary and sufficient for shutoff of host cell protein synthesis at early times post-infection. Using the vhs deletion mutant, we investigated the mechanism of BHV1-induced down-regulation of MHC class I cell surface expression. In contrast to BHV1 wild-type infection, the BHV1(vhs-) mutant allows detection of MHC class I molecules at much later time-points after infection. This illustrates the role the vhs protein plays in MHC class I down-regulation. However, even after infection with BHV1(vhs-), MHC class I cell surface expression is impaired. In BHV1(vhs-)-infected cells, MHC class I molecules are retained within the endoplasmic reticulum (ER). Moreover, the transporter associated with antigen presentation (TAP) is still blocked. Temporal control of viral protein expression using chemical inhibitors shows that viral protein(s) expressed within the early phase of BHV1 infection are responsible for ER retention of MHC class I molecules. These results indicate that multiple mechanisms are responsible for down-regulation of MHC class I molecules in BHV1-infected cells.

  6. Protective influences on experimental autoimmune encephalomyelitis by MHC class I and class II alleles

    DEFF Research Database (Denmark)

    Mustafa, M; Vingsbo, C; Olsson, T;

    1994-01-01

    Experimental autoimmune encephalomyelitis (EAE) is influenced by polymorphism of the MHC. We have previously found that Lewis rats with certain MHC haplotypes are susceptible to disease induced with the myelin basic protein (MBP) peptide 63-88, whereas Lewis rats with other MHC haplotypes...

  7. Tapasin-related protein TAPBPR is an additional component of the MHC class I presentation pathway

    OpenAIRE

    Boyle, Louise H.; Hermann, Clemens; Boname, Jessica M.; Porter, Keith M; Patel, Peysh A.; Burr, Marian L; Duncan, Lidia M.; Harbour, Michael E.; Rhodes, David A.; Skjødt, Karsten; Lehner, Paul J.; Trowsdale, John

    2013-01-01

    Tapasin is an integral component of the peptide-loading complex (PLC) important for efficient peptide loading onto MHC class I molecules. We investigated the function of the tapasin-related protein, TAPBPR. Like tapasin, TAPBPR is widely expressed, IFN-γ–inducible, and binds to MHC class I coupled with β2-microglobulin in the endoplasmic reticulum. In contrast to tapasin, TAPBPR does not bind ERp57 or calreticulin and is not an integral component of the PLC. β2-microglobulin is essential for ...

  8. Vaccination against lymphocytic choriomeningitis virus infection in MHC class II-deficient mice

    DEFF Research Database (Denmark)

    Holst, Peter Johannes; Christensen, Jan Pravsgaard; Thomsen, Allan Randrup

    2011-01-01

    response could be elicited in MHC class II-deficient mice by vaccination with adenovirus encoding lymphocytic choriomeningitis virus (LCMV) glycoprotein tethered to MHC class II-associated invariant chain. Moreover, the response induced conferred significant cytolytic CD8(+) T cell-mediated protection...... against challenge with a high dose of the invasive clone 13 strain of LCMV. In contrast, vaccination with adenovirus encoding unlinked LCMV glycoprotein induced weak virus control in the absence of CD4(+) T cells, and mice may die of increased immunopathology associated with incomplete protection. Acute...

  9. Predicting peptides binding to MHC class II molecules using multi-objective evolutionary algorithms

    Directory of Open Access Journals (Sweden)

    Feng Lin

    2007-11-01

    Full Text Available Abstract Background Peptides binding to Major Histocompatibility Complex (MHC class II molecules are crucial for initiation and regulation of immune responses. Predicting peptides that bind to a specific MHC molecule plays an important role in determining potential candidates for vaccines. The binding groove in class II MHC is open at both ends, allowing peptides longer than 9-mer to bind. Finding the consensus motif facilitating the binding of peptides to a MHC class II molecule is difficult because of different lengths of binding peptides and varying location of 9-mer binding core. The level of difficulty increases when the molecule is promiscuous and binds to a large number of low affinity peptides. In this paper, we propose two approaches using multi-objective evolutionary algorithms (MOEA for predicting peptides binding to MHC class II molecules. One uses the information from both binders and non-binders for self-discovery of motifs. The other, in addition, uses information from experimentally determined motifs for guided-discovery of motifs. Results The proposed methods are intended for finding peptides binding to MHC class II I-Ag7 molecule – a promiscuous binder to a large number of low affinity peptides. Cross-validation results across experiments on two motifs derived for I-Ag7 datasets demonstrate better generalization abilities and accuracies of the present method over earlier approaches. Further, the proposed method was validated and compared on two publicly available benchmark datasets: (1 an ensemble of qualitative HLA-DRB1*0401 peptide data obtained from five different sources, and (2 quantitative peptide data obtained for sixteen different alleles comprising of three mouse alleles and thirteen HLA alleles. The proposed method outperformed earlier methods on most datasets, indicating that it is well suited for finding peptides binding to MHC class II molecules. Conclusion We present two MOEA-based algorithms for finding motifs

  10. Influenza Virus Targets Class I MHC-Educated NK Cells for Immunoevasion.

    Directory of Open Access Journals (Sweden)

    Ahmad Bakur Mahmoud

    2016-02-01

    Full Text Available The immune response to influenza virus infection comprises both innate and adaptive defenses. NK cells play an early role in the destruction of tumors and virally-infected cells. NK cells express a variety of inhibitory receptors, including those of the Ly49 family, which are functional homologs of human killer-cell immunoglobulin-like receptors (KIR. Like human KIR, Ly49 receptors inhibit NK cell-mediated lysis by binding to major histocompatibility complex class I (MHC-I molecules that are expressed on normal cells. During NK cell maturation, the interaction of NK cell inhibitory Ly49 receptors with their MHC-I ligands results in two types of NK cells: licensed ("functional", or unlicensed ("hypofunctional". Despite being completely dysfunctional with regard to rejecting MHC-I-deficient cells, unlicensed NK cells represent up to half of the mature NK cell pool in rodents and humans, suggesting an alternative role for these cells in host defense. Here, we demonstrate that after influenza infection, MHC-I expression on lung epithelial cells is upregulated, and mice bearing unlicensed NK cells (Ly49-deficient NKCKD and MHC-I-deficient B2m-/- mice survive the infection better than WT mice. Importantly, transgenic expression of an inhibitory self-MHC-I-specific Ly49 receptor in NKCKD mice restores WT influenza susceptibility, confirming a direct role for Ly49. Conversely, F(ab'2-mediated blockade of self-MHC-I-specific Ly49 inhibitory receptors protects WT mice from influenza virus infection. Mechanistically, perforin-deficient NKCKD mice succumb to influenza infection rapidly, indicating that direct cytotoxicity is necessary for unlicensed NK cell-mediated protection. Our findings demonstrate that Ly49:MHC-I interactions play a critical role in influenza virus pathogenesis. We suggest a similar role may be conserved in human KIR, and their blockade may be protective in humans.

  11. Infection with an H2 recombinant herpes simplex virus vector results in expression of MHC class I antigens on the surfaces of human neuroblastoma cells in vitro and mouse sensory neurons in vivo.

    Science.gov (United States)

    Abendroth, A; Simmons, A; Efstathiou, S; Pereira, R A

    2000-10-01

    The majority of neurons in herpes simplex virus (HSV)-infected murine sensory ganglia are transiently induced to express MHC-I antigens at the cell surface, whereas only a minority are themselves productively infected. The aim of the current work was to determine whether MHC-I antigens can be expressed on the surfaces of infected neurons in addition to their uninfected neighbours. To address this aim a recombinant HSV type 1 strain, S-130, was used to deliver a mouse H2K(d) gene, under control of the HCMV IE-1 promoter/enhancer, into human neuroblastoma cells in vitro and mouse primary sensory neurons in vivo. S-130 expressed H2K(d) antigens on the surfaces of IMR-32 cells, a human neuroblastoma cell line that expresses very low levels of MHC-I constitutively. In K562 cells, which do not express MHC-I constitutively, H2K(d) and beta(2)-microglobulin (beta(2)m) were shown to be co-expressed at the cell surface following S-130 infection. This observation was taken as evidence that class I heavy chain (alphaC) molecules encoded by the expression cassette in the HSV genome were transported to the cell surface as stable complexes with beta(2)m. Significantly, after introduction of S-130 into flank skin, H2K(d) antigens were detected on the surfaces of primary sensory neurons in ganglia innervating the inoculation site. Our data show that HSV-infected murine primary sensory neurons and human neuroblastoma cells are capable of expressing cell-surface MHC-I molecules encoded by a transgene. From this, we infer that up-regulation of alphaC expression is, in principle, sufficient to overcome potential impediments to neuronal cell surface expression of MHC-I complexes.

  12. MHC class I epitope binding prediction trained on small data sets

    DEFF Research Database (Denmark)

    Lundegaard, Claus; Nielsen, Morten; Lamberth, K.;

    2004-01-01

    The identification of potential T-cell epitopes is important for development of new human or vetenary vaccines, both considering single protein/subunit vaccines, and for epitope/peptide vaccines as such. The highly diverse MHC class I alleles bind very different peptides, and accurate binding pre...... in situations where only very limited data are available for training....

  13. NetCTLpan: pan-specific MHC class I pathway epitope predictions

    DEFF Research Database (Denmark)

    Stranzl, Thomas; Larsen, Mette Voldby; Lundegaard, Claus;

    2010-01-01

    Reliable predictions of immunogenic peptides are essential in rational vaccine design and can minimize the experimental effort needed to identify epitopes. In this work, we describe a pan-specific major histocompatibility complex (MHC) class I epitope predictor, NetCTLpan. The method integrates...

  14. Selective transport of internalized antigens to the cytosol for MHC class I presentation in dendritic cells

    NARCIS (Netherlands)

    Rodriguez, A; Regnault, A; Kleijmeer, M; Ricciardi-Castagnoli, P; Amigorena, S

    1999-01-01

    In order for cytotoxic T cells to initiate immune responses, peptides derived from internalized antigens must be presented to the cytotoxic T cells on major histocompatibility complex (MHC) class I molecules. Here we show that dendritic cells, the only antigen-presenting cells that initiate immune r

  15. NetMHCpan, a method for MHC class I binding prediction beyond humans

    DEFF Research Database (Denmark)

    Hoof, Ilka; Peters, B; Sidney, J;

    2009-01-01

    immunologists in interpreting cellular immune responses in large out-bred populations is demonstrated. Further, we used NetMHCpan-2.0 to predict potential binding peptides for the pig MHC class I molecule SLA-1*0401. Ninety-three percent of the predicted peptides were demonstrated to bind stronger than 500 n...

  16. Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity

    DEFF Research Database (Denmark)

    Harndahl, Mikkel Nors; Rasmussen, Michael; Nielsen, Morten;

    2012-01-01

    Peptide-MHC class I stability is a stronger predictor of CTL immunogenicity than peptide affinity Mikkel Harndahla, Michael Rasmussena, Morten Nielsenb, Soren Buusa,∗ a Laboratory of Experimental Immunology, Faculty of Health Sciences, University of Copenhagen, Denmark b Center for Biological Seq...... al., 2007. J. Immunol. 178, 7890–7901. doi:10.1016/j.molimm.2012.02.025...

  17. Poor correspondence between predicted and experimental binding of peptides to class I MHC molecules

    DEFF Research Database (Denmark)

    Andersen, Mads Hald; Tan, L.; Søndergaard, Ib;

    2000-01-01

    Naturally processed peptides presented by class I major histocompatibility complex (MHC) molecules display a characteristic allele specific motif of two or more essential amino acid side chains, the so-called peptide anchor residues, in the context of an 8-10 amino acid long peptide. Knowledge of...

  18. Characterization and expression of MHC class II alpha and II beta genes in mangrove red snapper (Lutjanus argentimaculatus).

    Science.gov (United States)

    Wang, Tianyan; Tan, Shangjin; Cai, Zhonghua

    2015-12-01

    The major histocompatibility complex (MHC) class II plays a key role in adaptive immunity by presenting foreign peptides to CD4(+) T cells and by triggering the adaptive immune response. While the structure and function of MHC class II have been well characterized in mammalian, limited research has been done on fishes. In this study, we characterized the gene structure and expression of MHC class II α (Lunar-DAA) and II β (Lunar-DAB) of mangrove red snapper (Lutjanus argentimaculatus). Both genes shared, respectively, a high similarity and typical features with other vertebrate MHC class II α and II β. The phylogenetic analysis of the deduced peptides revealed that both Lunar-DAA and Lunar-DAB were located in the teleost subclass. Western blotting analyses indicated that both MHC class II α and II β were expressed ubiquitously in immune-related cells, tissues and organs, and that MHC class II α and II β chains existed mainly as heterodimers. While it was highly expressed in gills, thymus, head kidney (HK), spleen, head kidney macrophage and spleen leucocytes, MHC class II β chain was expressed with a low abundance in skin, intestine, stomach and heart. The highest expression of MHC class II β in thymus confirmed the conclusion that thymus is one of the primary lymphoid organs in fishes. The detection of MHC class II αβ dimers in HK macrophages and spleen leucocytes indicated that HK macrophages and spleen leucocytes play a critical role in the adaptive immunity in fishes. All these results provide valuable information for understanding the structure of MHC class II α and II β and their function in immune responses.

  19. NetMHC-3.0: accurate web accessible predictions of human, mouse and monkey MHC class I affinities for peptides of length 8-11.

    Science.gov (United States)

    Lundegaard, Claus; Lamberth, Kasper; Harndahl, Mikkel; Buus, Søren; Lund, Ole; Nielsen, Morten

    2008-07-01

    NetMHC-3.0 is trained on a large number of quantitative peptide data using both affinity data from the Immune Epitope Database and Analysis Resource (IEDB) and elution data from SYFPEITHI. The method generates high-accuracy predictions of major histocompatibility complex (MHC): peptide binding. The predictions are based on artificial neural networks trained on data from 55 MHC alleles (43 Human and 12 non-human), and position-specific scoring matrices (PSSMs) for additional 67 HLA alleles. As only the MHC class I prediction server is available, predictions are possible for peptides of length 8-11 for all 122 alleles. artificial neural network predictions are given as actual IC(50) values whereas PSSM predictions are given as a log-odds likelihood scores. The output is optionally available as download for easy post-processing. The training method underlying the server is the best available, and has been used to predict possible MHC-binding peptides in a series of pathogen viral proteomes including SARS, Influenza and HIV, resulting in an average of 75-80% confirmed MHC binders. Here, the performance is further validated and benchmarked using a large set of newly published affinity data, non-redundant to the training set. The server is free of use and available at: http://www.cbs.dtu.dk/services/NetMHC.

  20. Expressed MHC class II genes in sea otters (Enhydra lutris) from geographically disparate populations

    Science.gov (United States)

    Bowen, L.; Aldridge, B.M.; Miles, A.K.; Stott, J.L.

    2006-01-01

    The major histocompatibility complex (MHC) is central to maintaining the immunologic vigor of individuals and populations. Classical MHC class II genes were targeted for partial sequencing in sea otters (Enhydra lutris) from populations in California, Washington, and Alaska. Sequences derived from sea otter peripheral blood leukocyte mRNAs were similar to those classified as DQA, DQB, DRA, and DRB in other species. Comparisons of the derived amino acid compositions supported the classification of these as functional molecules from at least one DQA, DQB, and DRA locus and at least two DRB loci. While limited in scope, phylogenetic analysis of the DRB peptide-binding region suggested the possible existence of distinct clades demarcated by geographic region. These preliminary findings support the need for additional MHC gene sequencing and expansion to a comprehensive study targeting additional otters. ?? 2006 Blackwell Munksgaard.

  1. Influence of kinship and MHC class II genotype on visual traits in zebrafish larvae (Danio rerio).

    Science.gov (United States)

    Hinz, Cornelia; Gebhardt, Katharina; Hartmann, Alexander K; Sigman, Lauren; Gerlach, Gabriele

    2012-01-01

    Kin recognition can drive kin selection and the evolution of social behaviour. In zebrafish (Danio rerio, Hamilton 1822), kin recognition is based on olfactory and visual imprinting processes. If larvae are exposed to visual and chemical cues of kin at day 5 and 6 post fertilization they will recognize kin throughout life, while exposure to non-kin fails to trigger any recognition. Chemical imprinting signals are transcribed by polymorphic genes of the major histocompatibility complex (MHC) code; however, the underlying mechanism for visual imprinting remains unclear. Here we provide evidence for the existence of family-specific differences in morphometry and pigmentation pattern of six day old zebrafish larvae. While rump, tail and body pigmentation were dependent on relatedness, iris pigmentation and morphometry were also influenced by MHC class II genotype. Our study revealed that the MHC not only influences the chemical signature of individuals, but also their visual appearance. PMID:23251449

  2. NetMHC-3.0: accurate web accessible predictions of human, mouse and monkey MHC class I affinities for peptides of length 8-11

    DEFF Research Database (Denmark)

    Lundegaard, Claus; Lamberth, K; Harndahl, M;

    2008-01-01

    NetMHC-3.0 is trained on a large number of quantitative peptide data using both affinity data from the Immune Epitope Database and Analysis Resource (IEDB) and elution data from SYFPEITHI. The method generates high-accuracy predictions of major histocompatibility complex (MHC): peptide binding....... The predictions are based on artificial neural networks trained on data from 55 MHC alleles (43 Human and 12 non-human), and position-specific scoring matrices (PSSMs) for additional 67 HLA alleles. As only the MHC class I prediction server is available, predictions are possible for peptides of length 8......–11 for all 122 alleles. artificial neural network predictions are given as actual IC50 values whereas PSSM predictions are given as a log-odds likelihood scores. The output is optionally available as download for easy post-processing. The training method underlying the server is the best available, and has...

  3. Identification, inheritance, and linkage of B-G-like and MHC class I genes in cranes

    Science.gov (United States)

    Jarvi, S.I.; Goto, R.M.; Gee, G.F.; Briles, W.E.; Miller, M.M.

    1999-01-01

    We identified B-G-like genes in the whooping and Florida sandhill cranes and linked them to the major histocompatibility complex (MHC). We evaluated the inheritance of B-G-like genes in families of whooping and Florida sandhill cranes using restriction fragment patterns (RFPs). Two B-G-like genes, designated wcbgl and wcbg2, were located within 8 kb of one another. The fully sequenced wcbg2 gene encodes a B-G IgV-like domain, an additional Ig-like domain, a transmembrane domain, and a single heptad domain typical of '-helical coiled coils. Patterns of restriction fragments in DNA from the whooping crane and from a number of other species indicate that the B-G-like gene families of cranes are large with diverse sequences. Segregation of RFPs in families of Florida sandhill cranes provide evidence for genetic polymorphism in the B-G-like genes. The restriction fragments generally segregated in concert with MHC haplotypes assigned by serological typing and by single stranded conformational polymorphism (SSCP) assays based in the second exon of the crane MHC class I genes. This study supports the concept of a long-term association of polymorphic B-G-like genes with the MHC. It also establishes SSCP as a means for evaluating MHC genetic variability in cranes.

  4. Susceptibility of amphibians to chytridiomycosis is associated with MHC class II conformation.

    Science.gov (United States)

    Bataille, Arnaud; Cashins, Scott D; Grogan, Laura; Skerratt, Lee F; Hunter, David; McFadden, Michael; Scheele, Benjamin; Brannelly, Laura A; Macris, Amy; Harlow, Peter S; Bell, Sara; Berger, Lee; Waldman, Bruce

    2015-04-22

    The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause precipitous population declines in its amphibian hosts. Responses of individuals to infection vary greatly with the capacity of their immune system to respond to the pathogen. We used a combination of comparative and experimental approaches to identify major histocompatibility complex class II (MHC-II) alleles encoding molecules that foster the survival of Bd-infected amphibians. We found that Bd-resistant amphibians across four continents share common amino acids in three binding pockets of the MHC-II antigen-binding groove. Moreover, strong signals of selection acting on these specific sites were evident among all species co-existing with the pathogen. In the laboratory, we experimentally inoculated Australian tree frogs with Bd to test how each binding pocket conformation influences disease resistance. Only the conformation of MHC-II pocket 9 of surviving subjects matched those of Bd-resistant species. This MHC-II conformation thus may determine amphibian resistance to Bd, although other MHC-II binding pockets also may contribute to resistance. Rescuing amphibian biodiversity will depend on our understanding of amphibian immune defence mechanisms against Bd. The identification of adaptive genetic markers for Bd resistance represents an important step forward towards that goal.

  5. Towards the simplification of MHC typing protocols: targeting classical MHC class II genes in a passerine, the pied flycatcher Ficedula hypoleuca

    Directory of Open Access Journals (Sweden)

    Canal David

    2010-09-01

    Full Text Available Abstract Background Major Histocompatibility Complex (MHC has drawn the attention of evolutionary biologists due to its importance in crucial biological processes, such as sexual selection and immune response in jawed vertebrates. However, the characterization of classical MHC genes subjected to the effects of natural selection still remains elusive in many vertebrate groups. Here, we have tested the suitability of flanking intron sequences to guide the selective exploration of classical MHC genes driving the co-evolutionary dynamics between pathogens and their passerine (Aves, Order Passeriformes hosts. Findings Intronic sequences flanking the usually polymorphic exon 2 were isolated from different species using primers sitting on conserved coding regions of MHC class II genes (β chain. Taking the pied flycatcher Ficedula hypoleuca as an example, we demonstrate that careful primer design can evade non-classical MHC gene and pseudogene amplification. At least four polymorphic and expressed loci were co-replicated using a single pair of primers in five non-related individuals (N = 28 alleles. The cross-amplification and preliminary inspection of similar MHC fragments in eight unrelated songbird taxa suggests that similar approaches can also be applied to other species. Conclusions Intron sequences flanking the usually polymorphic exon 2 may assist the specific investigation of classical MHC class II B genes in species characterized by extensive gene duplication and pseudogenization. Importantly, the evasion of non-classical MHC genes with a more specific function and non-functional pseudogenes may accelerate data collection and diminish lab costs. Comprehensive knowledge of gene structure, polymorphism and expression profiles may be useful not only for the selective examination of evolutionarily relevant genes but also to restrict chimera formation by minimizing the number of co-amplifying loci.

  6. Expression regulation of major histocompatibility complex (MHC class I and class II encoding genes

    Directory of Open Access Journals (Sweden)

    Peter J van den Elsen

    2011-10-01

    Full Text Available MHC-I and MHC-II molecules play an essential role in the immune response to pathogens by virtue of their ability to present peptides to CD8+ and CD4+ T cells, respectively. Given this critical role, MHC-I and MHC-II genes are regulated in a tight fashion at the transcriptional level by a variety of transcription factors that interact with conserved cis-acting regulatory promoter elements. In addition to the activities of these regulatory factors, modification of chromatin also plays an essential role in the efficient transcription of these genes to meet with local requirement for an effective immune response. The focus of this review is on the transcription factors that interact with conserved cis-acting promoter elements and the epigenetic mechanisms that modulate induced and constitutive expression of these MHC genes.

  7. MHC class II molecules regulate growth in human T cells

    DEFF Research Database (Denmark)

    Nielsen, M; Odum, Niels; Bendtzen, K;

    1994-01-01

    modulate several T cell responses. Here, we studied further the role of class II molecules in the regulation of T cell growth. Costimulation of class II molecules by immobilized HLA-DR mAb significantly enhanced interleukin (IL)-2-supported T cell growth of the majority of CD4+, CD45RAlow, ROhigh T cell......-like) as well as T cells producing both cytokines (THO-like) responded to class II mAb. The costimulatory effect was not restricted to IL-2-driven T cell growth, since TCR/CD3-induced T cell activation was also enhanced by HLA-DR mAb. Moreover, class II costimulation potentiated CD28-mAb-induced T cell...

  8. Characterization of MHC class I in a long-distance migrant shorebird suggests multiple transcribed genes and intergenic recombination

    NARCIS (Netherlands)

    Buehler, Deborah M.; Verkuil, Yvonne I.; Tavares, Erika S.; Baker, Allan J.

    2013-01-01

    The major histocompatibility complex (MHC) includes highly polymorphic gene families encoding proteins crucial to the vertebrate acquired immune system. Classical MHC class I (MHCI) genes code for molecules expressed on the surfaces of most nucleated cells and are associated with defense against int

  9. Pan-Specific Prediction of Peptide-MHC Class I Complex Stability, a Correlate of T Cell Immunogenicity.

    Science.gov (United States)

    Rasmussen, Michael; Fenoy, Emilio; Harndahl, Mikkel; Kristensen, Anne Bregnballe; Nielsen, Ida Kallehauge; Nielsen, Morten; Buus, Søren

    2016-08-15

    Binding of peptides to MHC class I (MHC-I) molecules is the most selective event in the processing and presentation of Ags to CTL, and insights into the mechanisms that govern peptide-MHC-I binding should facilitate our understanding of CTL biology. Peptide-MHC-I interactions have traditionally been quantified by the strength of the interaction, that is, the binding affinity, yet it has been shown that the stability of the peptide-MHC-I complex is a better correlate of immunogenicity compared with binding affinity. In this study, we have experimentally analyzed peptide-MHC-I complex stability of a large panel of human MHC-I allotypes and generated a body of data sufficient to develop a neural network-based pan-specific predictor of peptide-MHC-I complex stability. Integrating the neural network predictors of peptide-MHC-I complex stability with state-of-the-art predictors of peptide-MHC-I binding is shown to significantly improve the prediction of CTL epitopes. The method is publicly available at http://www.cbs.dtu.dk/services/NetMHCstabpan. PMID:27402703

  10. Intracellular assembly and trafficking of MHC class Ⅰ molecules%MHCⅠ类分子胞内组装、转运及其调控机制的研究进展

    Institute of Scientific and Technical Information of China (English)

    林凯龙; 邹丽云; 万瑛

    2012-01-01

    MHC Ⅰ类分子是启动机体免疫应答的重要分子.当细胞遭受病毒感染或本身发生癌变,MHC Ⅰ类分子能结合病毒或癌变细胞蛋白降解形成的多肽,向CD8+T细胞报告病毒或者肿瘤的存在,从而促使其对异常细胞的杀伤.在此过程中,MHC Ⅰ类分子的胞内转运途径精密调控着免疫应答的效率,但目前对MHC Ⅰ类分子在胞内转运途径的机制了解不多.本综述就MHC Ⅰ类分子在内质网的组装、外运以及内吞后降解或再循环过程中的主要机制做一阐述,并且介绍一些新发现的相关调控分子.%MHC Class I molecules express on all nucleated cells and play an important role in triggering immune response. MHC class I molecules bind peptide fragments of intracellular proteins and display them at the cell surface where they function to report the presence of virus or tumors to CD8 + T cells. In this process, intracellular assembly and trafficking of MHC class I molecules regulate the efficiency of immune response, but little is known about the precise mechanisms. We review recent progress in our understanding of class I assembly, anterograde transport, endocytosis and recycling.

  11. Diversification of porcine MHC class II genes: evidence for selective advantage.

    Science.gov (United States)

    Luetkemeier, Erin S; Malhi, Ripan S; Beever, Jonathan E; Schook, Lawrence B

    2009-02-01

    The major histocompatibility complex (MHC) is an immunological gene-dense region of high diversity in mammalian species. Sus scrofa was domesticated by at least six independent events over Eurasia during the Holocene period. It has been hypothesized that the level and distribution of MHC variation in pig populations reflect genetic selection and environmental influences. In an effort to define the complexity of MHC polymorphisms and the role of selection in the generation of class II gene diversity (DQB, DRB1, and pseudogene PsiDRB3), DNA from globally distributed unrelated domestic pigs of European and Asian origins and a Suidae out-group was analyzed. The number of pseudogene alleles identified (PsiDRB3 33) was greater than those found in the expressed genes (DQB 20 and DRB1 23) but the level of observed heterozygosity (PsiDRB3 0.452, DQB 0.732, and DRB1 0.767) and sequence diversity (PsiDRB3 0.029, DQB 0.062, and DRB1 0.074) were significantly lower in the pseudogene, respectively. The substitution ratios reflected an excess of d (N) (DQB 1.476, DRB1 1.724, and PsiDRB3 0.508) and the persistence of expressed gene alleles suggesting the influence of balancing selection, while the pseudogene was undergoing purifying selection. The lack of a clear MHC phylogeographic tree, coupled with close genetic distances observed between the European and Asian populations (DQB 0.047 and DRB1 0.063) suggested that unlike observations using mtDNA, the MHC diversity lacks phylogeographic structure and appears to be globally uniform. Taken together, these results suggest that, despite regional differences in selective breeding and environments, no skewing of MHC diversity has occurred.

  12. Diversification of porcine MHC class II genes: evidence for selective advantage.

    Science.gov (United States)

    Luetkemeier, Erin S; Malhi, Ripan S; Beever, Jonathan E; Schook, Lawrence B

    2009-02-01

    The major histocompatibility complex (MHC) is an immunological gene-dense region of high diversity in mammalian species. Sus scrofa was domesticated by at least six independent events over Eurasia during the Holocene period. It has been hypothesized that the level and distribution of MHC variation in pig populations reflect genetic selection and environmental influences. In an effort to define the complexity of MHC polymorphisms and the role of selection in the generation of class II gene diversity (DQB, DRB1, and pseudogene PsiDRB3), DNA from globally distributed unrelated domestic pigs of European and Asian origins and a Suidae out-group was analyzed. The number of pseudogene alleles identified (PsiDRB3 33) was greater than those found in the expressed genes (DQB 20 and DRB1 23) but the level of observed heterozygosity (PsiDRB3 0.452, DQB 0.732, and DRB1 0.767) and sequence diversity (PsiDRB3 0.029, DQB 0.062, and DRB1 0.074) were significantly lower in the pseudogene, respectively. The substitution ratios reflected an excess of d (N) (DQB 1.476, DRB1 1.724, and PsiDRB3 0.508) and the persistence of expressed gene alleles suggesting the influence of balancing selection, while the pseudogene was undergoing purifying selection. The lack of a clear MHC phylogeographic tree, coupled with close genetic distances observed between the European and Asian populations (DQB 0.047 and DRB1 0.063) suggested that unlike observations using mtDNA, the MHC diversity lacks phylogeographic structure and appears to be globally uniform. Taken together, these results suggest that, despite regional differences in selective breeding and environments, no skewing of MHC diversity has occurred. PMID:19142631

  13. Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane

    DEFF Research Database (Denmark)

    La Rocca, Rosanna; Tallerico, Rossana; Hassan, Almosawy Talib;

    2014-01-01

    treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells......In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were...... between 700–1800 cm-1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased...

  14. The Specificity of Trimming of MHC Class I-Presented Peptides in the Endoplasmic Reticulum1

    OpenAIRE

    Hearn, Arron; Ian A York; Rock, Kenneth L.

    2009-01-01

    Aminopeptidases in the endoplasmic reticulum (ER) can cleave antigenic peptides and in so doing either create or destroy MHC class I-presented epitopes. However the specificity of this trimming process overall and of the major ER aminopeptidase ERAP1 in particular is not well understood. This issue is important because peptide trimming influences the magnitude and specificity of CD8 T cell responses. By systematically varying the N-terminal flanking sequences of peptides in a cell free bioche...

  15. NetMHCpan-3.0; improved prediction of binding to MHC class I molecules integrating information from multiple receptor and peptide length datasets

    DEFF Research Database (Denmark)

    Nielsen, Morten; Andreatta, Massimo

    2016-01-01

    Background: Binding of peptides to MHC class I molecules (MHC-I) is essential for antigen presentation to cytotoxic T-cells.Results: Here, we demonstrate how a simple alignment step allowing insertions and deletions in a pan-specific MHC-I binding machine-learning model enables combining informat......Background: Binding of peptides to MHC class I molecules (MHC-I) is essential for antigen presentation to cytotoxic T-cells.Results: Here, we demonstrate how a simple alignment step allowing insertions and deletions in a pan-specific MHC-I binding machine-learning model enables combining...

  16. Expression and characterization of recombinant single-chain salmon class I MHC fused with beta2-microglobulin with biological activity

    DEFF Research Database (Denmark)

    Zhao, Heng; Stet, René J M; Skjødt, Karsten;

    2008-01-01

    Heterodimeric class I major histocompatibility complex (MHC) molecules consist of a putative 45-kDa heavy chain and a 12-kDa beta2-microglobulin (beta2m) light chain. The knowledge about MHC genes in Atlantic salmon accumulated during the last decade has allowed us to generate soluble and stable...... antibodies were successfully produced against both the MHC class I heavy chain and beta(2)m, and showed binding to the recombinant molecule. The recombinant complex Sasabeta2mUBA*0301 was expressed and isolated; the production was scaled up by adjusting to its optimal conditions. Subsequently...

  17. DPA1*02012: A DPA1*0201-related Mhc class II allele in West Africa

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.G.; May, J.; Spauke, D.; Schnittger, L. [Bernhard Nocht Institute for Tropical Medicine, Hamburg (Germany)

    1994-12-31

    DNA techniques such as sequence-specific oligonucleotide probe (SSOP) hybridizations, restriction-fragment length polymorphism (RFLP) analyses, and DNA sequencing have greatly supported the characterization of Mhc class II allelic polymorphism. Here the authors describe a DPA 1 allele which has been identified in two male individuals from Liberia and Benin, West Africa, during a survey study on Mhc class II associations with the different manifestations after infection with Onchocerca volvulus. 4 refs., 1 fig.

  18. Probing natural killer cell education by Ly49 receptor expression analysis and computational modelling in single MHC class I mice.

    Directory of Open Access Journals (Sweden)

    Sofia Johansson

    Full Text Available Murine natural killer (NK cells express inhibitory Ly49 receptors for MHC class I molecules, which allows for "missing self" recognition of cells that downregulate MHC class I expression. During murine NK cell development, host MHC class I molecules impose an "educating impact" on the NK cell pool. As a result, mice with different MHC class I expression display different frequency distributions of Ly49 receptor combinations on NK cells. Two models have been put forward to explain this impact. The two-step selection model proposes a stochastic Ly49 receptor expression followed by selection for NK cells expressing appropriate receptor combinations. The sequential model, on the other hand, proposes that each NK cell sequentially expresses Ly49 receptors until an interaction of sufficient magnitude with self-class I MHC is reached for the NK cell to mature. With the aim to clarify which one of these models is most likely to reflect the actual biological process, we simulated the two educational schemes by mathematical modelling, and fitted the results to Ly49 expression patterns, which were analyzed in mice expressing single MHC class I molecules. Our results favour the two-step selection model over the sequential model. Furthermore, the MHC class I environment favoured maturation of NK cells expressing one or a few self receptors, suggesting a possible step of positive selection in NK cell education. Based on the predicted Ly49 binding preferences revealed by the model, we also propose, that Ly49 receptors are more promiscuous than previously thought in their interactions with MHC class I molecules, which was supported by functional studies of NK cell subsets expressing individual Ly49 receptors.

  19. Patterns of evolution of MHC class II genes of crows (Corvus suggest trans-species polymorphism

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    John A. Eimes

    2015-03-01

    Full Text Available A distinguishing characteristic of genes that code for the major histocompatibility complex (MHC is that alleles often share more similarity between, rather than within species. There are two likely mechanisms that can explain this pattern: convergent evolution and trans-species polymorphism (TSP, in which ancient allelic lineages are maintained by balancing selection and retained by descendant species. Distinguishing between these two mechanisms has major implications in how we view adaptation of immune genes. In this study we analyzed exon 2 of the MHC class IIB in three passerine bird species in the genus Corvus: jungle crows (Corvus macrorhynchos japonensis American crows (C. brachyrhynchos and carrion crows (C. corone orientalis. Carrion crows and American crows are recently diverged, but allopatric, sister species, whereas carrion crows and jungle crows are more distantly related but sympatric species, and possibly share pathogens linked to MHC IIB polymorphisms. These patterns of evolutionary divergence and current geographic ranges enabled us to test for trans-species polymorphism and convergent evolution of the MHC IIB in crows. Phylogenetic reconstructions of MHC IIB sequences revealed several well supported interspecific clusters containing all three species, and there was no biased clustering of variants among the sympatric carrion crows and jungle crows. The topologies of phylogenetic trees constructed from putatively selected sites were remarkably different than those constructed from putatively neutral sites. In addition, trees constructed using non-synonymous substitutions from a continuous fragment of exon 2 had more, and generally more inclusive, supported interspecific MHC IIB variant clusters than those constructed from the same fragment using synonymous substitutions. These phylogenetic patterns suggest that recombination, especially gene conversion, has partially erased the signal of allelic ancestry in these species. While

  20. A transcription map of the major histocompatibility complex (MHC) Class I region

    Energy Technology Data Exchange (ETDEWEB)

    Gruen, J.R.; Nalabolu, S.R.; Chu, T.W. [Yale Univ. School of Medicine, New Haven, CT (United States)] [and others

    1996-08-15

    We have applied cDNA hybridization selection to nine YACs spanning 3 Mb of genomic DNA from a region centromeric to HLA-A to the histone cluster that lies telomeric to the human major histocompatibility complex (MHC). In addition to Class I genes and pseudogenes, we describe over 63 genes and 23 additional expressed sequence tags distributed throughout the region. Many of the full-length genes belong to gene families. Prominent among these are a group of genes encoding proteins showing homology to the carboxyl-terminal sequences of butyrophilin and an additional group of zinc finger genes. We also detected several previously undefined genes that are specifically expressed in cells of the immune system, indicating a more complex role of the MHC in the immune response than has been appreciated. 102 refs., 2 figs., 3 tabs.

  1. Polymorphism and Balancing Selection of MHC Class II DAB Gene in 7 Selective Flounder (Paralichthys olivaceus Families

    Directory of Open Access Journals (Sweden)

    Min Du

    2011-01-01

    Full Text Available In order to determine the genetic variation of the MHC class IIB exon2 allele in the offspring, 700 fry from seven families of Japanese flounder challenged with V. anguillarum were studied, and different mortality rates were found in those families. Five to ten surviving and dead fry from each of the seven families were selected to study the MHC class II B exon2 gene with PCR and a direct sequencing method. One hundred and sixteen different exon2 sequences were found and 116 different alleles were identified, while a minimum of four loci were revealed in the MHC class II B exon2 gene. The ratio (dN/dS of nonsynonymous substitution (dN to synonymous substitutions (dS in the peptide-binding region (PBR of the MHC class IIB gene was 6.234, which indicated that balancing selection is acting on the MHC class IIB genes. The MHC IIB alleles were thus being passed on to their progeny. Some alleles were significantly more frequent in surviving than dead individuals. All together our data suggested that the alleles Paol-DAB*4301, Paol-DAB*4601, Paol-DAB*4302, Paol-DAB*3803, and Paol-DAB*4101 were associated with resistance to V. anguillarum in flounder.

  2. Oral HPV infection and MHC class II deficiency (A study of two cases with atypical outcome

    Directory of Open Access Journals (Sweden)

    Guirat-Dhouib Naouel

    2012-04-01

    Full Text Available Abstract Background Major histocompatibility complex class II deficiency, also referred to as bare lymphocyte syndrome is a rare primary Immunodeficiency disorder characterized by a profondly deficient human leukocyte antigen class II expression and a lack of cellular and humoral immune responses to foreign antigens. Clinical manifestations include extreme susceptibility to viral, bacterial, and fungal infections. The infections begin in the first year of life and involve usually the respiratory system and the gastrointestinal tract. Severe malabsorption with failure to thrive ensues, often leading to death in early childhood. Bone marrow transplantation is the curative treatment. Case reports Here we report two cases with a late outcome MHC class II deficiency. They had a long term history of recurrent bronchopulmonary and gastrointestinal infections. Bone marrow transplantation could not be performed because no compatible donor had been identified. At the age of 12 years, they developed oral papillomatous lesions related to HPV (human papillomavirus. The diagnosis of HPV infection was done by histological examination. HPV typing performed on the tissue obtained at biopsy showed HPV type 6. The lesions were partially removed after two months of laser treatment. Conclusions Viral infections are common in patients with MHC class II and remain the main cause of death. Besides warts caused by HPV infection do not exhibit a propensity for malignant transformation; they can cause great psychosocial morbidity.

  3. KIR polymorphisms modulate peptide-dependent binding to an MHC class I ligand with a Bw6 motif.

    Directory of Open Access Journals (Sweden)

    Arnaud D Colantonio

    2011-03-01

    Full Text Available Molecular interactions between killer immunoglobulin-like receptors (KIRs and their MHC class I ligands play a central role in the regulation of natural killer (NK cell responses to viral pathogens and tumors. Here we identify Mamu-A1*00201 (Mamu-A*02, a common MHC class I molecule in the rhesus macaque with a canonical Bw6 motif, as a ligand for Mamu-KIR3DL05. Mamu-A1*00201 tetramers folded with certain SIV peptides, but not others, directly stained primary NK cells and Jurkat cells expressing multiple allotypes of Mamu-KIR3DL05. Differences in binding avidity were associated with polymorphisms in the D0 and D1 domains of Mamu-KIR3DL05, whereas differences in peptide-selectivity mapped to the D1 domain. The reciprocal exchange of the third predicted MHC class I-contact loop of the D1 domain switched the specificity of two Mamu-KIR3DL05 allotypes for different Mamu-A1*00201-peptide complexes. Consistent with the function of an inhibitory KIR, incubation of lymphocytes from Mamu-KIR3DL05(+ macaques with target cells expressing Mamu-A1*00201 suppressed the degranulation of tetramer-positive NK cells. These observations reveal a previously unappreciated role for D1 polymorphisms in determining the selectivity of KIRs for MHC class I-bound peptides, and identify the first functional KIR-MHC class I interaction in the rhesus macaque. The modulation of KIR-MHC class I interactions by viral peptides has important implications to pathogenesis, since it suggests that the immunodeficiency viruses, and potentially other types of viruses and tumors, may acquire changes in epitopes that increase the affinity of certain MHC class I ligands for inhibitory KIRs to prevent the activation of specific NK cell subsets.

  4. Targeting tumor-associated antigens to the MHC class I presentation pathway.

    Science.gov (United States)

    Gross, G; Margalit, A

    2007-06-01

    There is little doubt that cytotoxic T lymphocytes (CTLs) can kill tumor cells in-vivo. However, most CTL-inducing immunization protocols examined so far in cancer patients have yielded only limited clinical benefits, underscoring the urge to improve current approaches for the effective induction of tumor-reactive CTLs. The tumor side of the immunological frontline is armed with large masses, high mutability and an arsenal of immune evasion and suppression mechanisms. Accordingly, the confronting CTLs should come in large numbers, recognize an assortment of MHC class I (MHC-I) bound tumor-associated peptides and be brought into action under effective immunostimulatory conditions. Naïve CTLs are activated to become effector cells in secondary lymphoid organs, following their productive encounter with MHC-I-bound peptides at the surface of dendritic cells (DCs). Therefore, many cancer vaccines under development focus on the optimization of peptide presentation by DCs at this critical stage. The elucidation of discrete steps and the subsequent identification of inherent bottlenecks in the MHC-I antigen presentation pathway have fueled elaborate efforts to enhance vaccine efficacy by the rational targeting of proteins or peptides, formulated into these vaccines, to this pathway. Protein- and gene-based strategies are accordingly devised to deliver tumor-associated peptides to selected cellular compartments, which are essential for the generation of functional CTL ligands. Many of these strategies target the conventional, endogenous route, while others harness the unique pathways that enable DCs to present exogenous antigens, known as cross-presentation. Here we dissect the intricate machinery that produces CTL ligands and examine how knowledge-based cancer vaccines can target the sequence of workstations, biochemical utensils and molecular intermediates comprising this production line.

  5. Targeting tumor-associated antigens to the MHC class I presentation pathway.

    Science.gov (United States)

    Gross, G; Margalit, A

    2007-06-01

    There is little doubt that cytotoxic T lymphocytes (CTLs) can kill tumor cells in-vivo. However, most CTL-inducing immunization protocols examined so far in cancer patients have yielded only limited clinical benefits, underscoring the urge to improve current approaches for the effective induction of tumor-reactive CTLs. The tumor side of the immunological frontline is armed with large masses, high mutability and an arsenal of immune evasion and suppression mechanisms. Accordingly, the confronting CTLs should come in large numbers, recognize an assortment of MHC class I (MHC-I) bound tumor-associated peptides and be brought into action under effective immunostimulatory conditions. Naïve CTLs are activated to become effector cells in secondary lymphoid organs, following their productive encounter with MHC-I-bound peptides at the surface of dendritic cells (DCs). Therefore, many cancer vaccines under development focus on the optimization of peptide presentation by DCs at this critical stage. The elucidation of discrete steps and the subsequent identification of inherent bottlenecks in the MHC-I antigen presentation pathway have fueled elaborate efforts to enhance vaccine efficacy by the rational targeting of proteins or peptides, formulated into these vaccines, to this pathway. Protein- and gene-based strategies are accordingly devised to deliver tumor-associated peptides to selected cellular compartments, which are essential for the generation of functional CTL ligands. Many of these strategies target the conventional, endogenous route, while others harness the unique pathways that enable DCs to present exogenous antigens, known as cross-presentation. Here we dissect the intricate machinery that produces CTL ligands and examine how knowledge-based cancer vaccines can target the sequence of workstations, biochemical utensils and molecular intermediates comprising this production line. PMID:17584150

  6. Analysis of the non classical class I genes of the MHC in swine

    OpenAIRE

    Rui, Hu

    2011-01-01

    In pig, very little information is available on the three non classical MHC class I genes SLA-6, -7 and -8 (SLA-Ib genes). Our aim was to increase knowledge on SLA-Ib genes by studying their polymorphism, transcription and protein expression. Full length transcripts were characterized from thymus and brain of MeLiM pigs resulting in the annotation of 8 exons for SLA-7 and -8 and 7 exons for SLA-6. The three full length cDNAs encode molecules with a predicted folding consistent with peptide pr...

  7. Role of PU.1 in MHC Class II Expression via CIITA Transcription in Plasmacytoid Dendritic Cells.

    Science.gov (United States)

    Miura, Ryosuke; Kasakura, Kazumi; Nakano, Nobuhiro; Hara, Mutsuko; Maeda, Keiko; Okumura, Ko; Ogawa, Hideoki; Yashiro, Takuya; Nishiyama, Chiharu

    2016-01-01

    The cofactor CIITA is a master regulator of MHC class II expression and several transcription factors regulating the cell type-specific expression of CIITA have been identified. Although the MHC class II expression in plasmacytoid dendritic cells (pDCs) is also mediated by CIITA, the transcription factors involved in the CIITA expression in pDCs are largely unknown. In the present study, we analyzed the role of a hematopoietic lineage-specific transcription factor, PU.1, in CIITA transcription in pDCs. The introduction of PU.1 siRNA into mouse pDCs and a human pDC cell line, CAL-1, reduced the mRNA levels of MHC class II and CIITA. When the binding of PU.1 to the 3rd promoter of CIITA (pIII) in CAL-1 and mouse pDCs was analyzed by a chromatin immunoprecipitation assay, a significant amount of PU.1 binding to the pIII was detected, which was definitely decreased in PU.1 siRNA-transfected cells. Reporter assays showed that PU.1 knockdown reduced the pIII promoter activity and that three Ets-motifs in the human pIII promoter were candidates of cis-enhancing elements. By electrophoretic mobility shift assays, it was confirmed that two Ets-motifs, GGAA (-181/-178) and AGAA (-114/-111), among three candidates, were directly bound with PU.1. When mouse pDCs and CAL-1 cells were stimulated by GM-CSF, mRNA levels of PU.1, pIII-driven CIITA, total CIITA, MHC class II, and the amount of PU.1 binding to pIII were significantly increased. The GM-CSF-mediated up-regulation of these mRNAs was canceled in PU.1 siRNA-introduced cells. Taking these results together, we conclude that PU.1 transactivates the pIII through direct binding to Ets-motifs in the promoter in pDCs.

  8. Selection, diversity and evolutionary patterns of the MHC class II DAB in free-ranging Neotropical marsupials

    Directory of Open Access Journals (Sweden)

    Otten Celine

    2008-06-01

    Full Text Available Abstract Background Research on the genetic architecture and diversity of the MHC has focused mainly on eutherian mammals, birds and fish. So far, studies on model marsupials used in laboratory investigations indicated very little or even no variation in MHC class II genes. However, natural levels of diversity and selection are unknown in marsupials as studies on wild populations are virtually absent. We used two endemic South American mouse opossums, Gracilinanus microtarsus and Marmosops incanus, to investigate characteristic features of MHC selection. This study is the first investigation of MHC selection in free-ranging Neotropical marsupials. In addition, the evolutionary history of MHC lineages within the group of marsupials was examined. Results G. microtarsus showed extensive levels of MHC diversity within and among individuals as 47 MHC-DAB alleles and high levels of sequence divergence were detected at a minimum of four loci. Positively selected codon sites were identified, of which most were congruent with human antigen binding sites. The diversity in M. incanus was rather low with only eight observed alleles at presumably two loci. However, these alleles also revealed high sequence divergence. Again, positive selection was identified on specific codon sites, all congruent with human ABS and with positively selected sites observed in G. microtarsus. In a phylogenetic comparison alleles of M. incanus interspersed widely within alleles of G. microtarsus with four alleles being present in both species. Conclusion Our investigations revealed extensive MHC class II polymorphism in a natural marsupial population, contrary to previous assumptions. Furthermore, our study confirms for the first time in marsupials the presence of three characteristic features common at MHC loci of eutherian mammals, birds and fish: large allelic sequence divergence, positive selection on specific sites and trans-specific polymorphism.

  9. Mapping and characterization of non-HLA multigene assemblages in the human MHC class I region

    Energy Technology Data Exchange (ETDEWEB)

    Venditti, C.P.; Harris, J.M.; Geraghty, D.E. [Pennsylvania State Univ. College of Medicine, Hershey, PA (United States)] [and others

    1994-07-15

    The major histocompatibility complex (MHC) class I region has been shown to be associated with a variety of immune and nonimmune disorders. In an effort to initiate steps designed to identify the idiopathic hemochromatosis disease gene (HFE), the authors have cloned and mapped two expressed messages using probes from the HLA-H subregion that lie immediately distal to the HLA-A9 breakpoint. Although the cDNA clones identify distinct multifragment families that are dispersed throughout the MHC, the gene sequences from which the two cDNA clones derive map centromeric to the HLA-B locus and are absent from the genomes of higher nonhuman primates. This suggests that a syntenic coding segment arose within a highly polymorphic region (TNF to HLA-B interval) as the result of an insertion event following the emergence of Homo sapiens. An additional syntenic cluster exists within a peak of linkage disequilibrium with the HFE gene and may define coding sequences that underlie the defect in genetic iron overload. These data generally support the concept that the class I region is potentially gene-rich and further highlight the possibility that these new coding sequences may play a role in the development of a variety of HLA-linked diseases. The observations presented suggest that interlocus exchanges have played a structural role in the genesis of the human class I region. 46 refs., 6 refs.

  10. The nonconventional MHC class II molecule DM governs diabetes susceptibility in NOD mice.

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    Marc A J Morgan

    Full Text Available The spontaneous destruction of insulin producing pancreatic beta cells in non-obese diabetic (NOD mice provides a valuable model of type 1 diabetes. As in humans, disease susceptibility is controlled by the classical MHC class II genes that guide CD4(+ T cell responses to self and foreign antigens. It has long been suspected that the dedicated class II chaperone designated HLA-DM in humans or H-2M in mice also makes an important contribution, but due to tight linkage within the MHC, a possible role played by DM peptide editing has not been previously tested by conventional genetic approaches. Here we exploited newly established germ-line competent NOD ES cells to engineer a loss of function allele. DM deficient NOD mice display defective class II peptide occupancy and surface expression, and are completely protected against type 1 diabetes. Interestingly the mutation results in increased proportional representation of CD4(+Foxp3(+ regulatory T cells and the absence of pathogenic CD4(+ T effectors. Overall, this striking phenotype establishes that DM-mediated peptide selection plays an essential role in the development of autoimmune diabetes in NOD mice.

  11. Contrasting epidemic histories reveal pathogen-mediated balancing selection on class II MHC diversity in a wild songbird.

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    Dana M Hawley

    Full Text Available The extent to which pathogens maintain the extraordinary polymorphism at vertebrate Major Histocompatibility Complex (MHC genes via balancing selection has intrigued evolutionary biologists for over half a century, but direct tests remain challenging. Here we examine whether a well-characterized epidemic of Mycoplasmal conjunctivitis resulted in balancing selection on class II MHC in a wild songbird host, the house finch (Carpodacus mexicanus. First, we confirmed the potential for pathogen-mediated balancing selection by experimentally demonstrating that house finches with intermediate to high multi-locus MHC diversity are more resistant to challenge with Mycoplasma gallisepticum. Second, we documented sequence and diversity-based signatures of pathogen-mediated balancing selection at class II MHC in exposed host populations that were absent in unexposed, control populations across an equivalent time period. Multi-locus MHC diversity significantly increased in exposed host populations following the epidemic despite initial compromised diversity levels from a recent introduction bottleneck in the exposed host range. We did not observe equivalent changes in allelic diversity or heterozygosity across eight neutral microsatellite loci, suggesting that the observations reflect selection rather than neutral demographic processes. Our results indicate that a virulent pathogen can exert sufficient balancing selection on class II MHC to rescue compromised levels of genetic variation for host resistance in a recently bottlenecked population. These results provide evidence for Haldane's long-standing hypothesis that pathogens directly contribute to the maintenance of the tremendous levels of genetic variation detected in natural populations of vertebrates.

  12. Characterization of major histocompatibility complex class I loci of the lark sparrow (Chondestes grammacus) and insights into avian MHC evolution.

    Science.gov (United States)

    Lyons, Amanda C; Hoostal, Matthew J; Bouzat, Juan L

    2015-08-01

    The major histocompatibilty complex (MHC) has become increasingly important in the study of the immunocapabilities of non-model vertebrates due to its direct involvement in the immune response. The characterization of MHC class I loci in the lark sparrow (Chondestes grammacus) revealed multiple MHC class I loci with elevated genetic diversity at exon 3, evidence of differential selection between the peptide binding region (PBR) and non-PBR, and the presence of multiple pseudogenes with limited divergence. The minimum number of functional MHC class I loci was estimated at four. Sequence analysis revealed d N /d S ratios significantly less than one at non-PBR sites, indicative of negative selection, whereas PBR sites associated with antigen recognition showed ratios greater than 1 but non-significant. GenBank surveys and phylogenetic analyses of previously reported avian MHC class I sequences revealed variable signatures of evolutionary processes acting upon this gene family, including gene duplication and potential concerted evolution. An increase in the number of class I loci across species coincided with an increase in pseudogene prevalence, revealing the importance of gene duplication in the expansion of multigene families and the creation of pseudogenes.

  13. Natural host genetic resistance to lentiviral CNS disease: a neuroprotective MHC class I allele in SIV-infected macaques.

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    Joseph L Mankowski

    Full Text Available Human immunodeficiency virus (HIV infection frequently causes neurologic disease even with anti-retroviral treatment. Although associations between MHC class I alleles and acquired immunodeficiency syndrome (AIDS have been reported, the role MHC class I alleles play in restricting development of HIV-induced organ-specific diseases, including neurologic disease, has not been characterized. This study examined the relationship between expression of the MHC class I allele Mane-A*10 and development of lentiviral-induced central nervous system (CNS disease using a well-characterized simian immunodeficiency (SIV/pigtailed macaque model. The risk of developing CNS disease (SIV encephalitis was 2.5 times higher for animals that did not express the MHC class I allele Mane-A*10 (P = 0.002; RR = 2.5. Animals expressing the Mane-A*10 allele had significantly lower amounts of activated macrophages, SIV RNA, and neuronal dysfunction in the CNS than Mane-A*10 negative animals (P<0.001. Mane-A*10 positive animals with the highest CNS viral burdens contained SIV gag escape mutants at the Mane-A*10-restricted KP9 epitope in the CNS whereas wild type KP9 sequences dominated in the brain of Mane-A*10 negative animals with comparable CNS viral burdens. These concordant findings demonstrate that particular MHC class I alleles play major neuroprotective roles in lentiviral-induced CNS disease.

  14. Assessment of 188Re marked anti MHC class Ⅱ antibody by peripheral blood mononuclear cells stimulated by donor alloantigen

    Institute of Scientific and Technical Information of China (English)

    DING Guo-ping; CAO Li-ping; LIU Jie; LIU Da-ren; QUE Ri-sheng; ZHU Lin-hua; ZHOU Yi-ming; MAO Ke-jie; HU Jun-an

    2011-01-01

    Background Previous studies showed that anti MHC-Ⅱ monoclone antibody (MAb) only had partial inhibiting effect of alloreactive mixed lymphocyte reaction (MLR) in vitro and it was unsteady and non-persistent. The aim of this research was to determine whether radioactive isotope 188Re marked MHC-Ⅱ antibody could benefit the allograft acceptance in transplantation as compared to normal MHC-Ⅱ antibody.Methods 188Re was incorporated to 2E9/13F(ab')2 which is against swine MHC class Ⅱ antigen (MAb-188Re). Porcine peripheral blood mononuclear (PBMC) cells were examined for proliferation and cytokine mRNA expression after stimulation with MHC-Ⅱ MAb or MAb-188Re.Results The proliferative response of recipient PBMCs in mixed lymphocyte reaction (MLR) to donor alloantigen showed that the stimulation index of MAb-188Re group was significantly lower than the MHC-Ⅱ MAb group and control (P<0.05). mRNA expression of interleukin 2, interferon Y and tumor necrosis factor α (type 1 cytokines) was lower in MAb-188Re group than the MHC-Ⅱ MAb group, while interleukin 10 (type 2 cytokines) was higher in MAb-188Re group in the first 24 hours.Conclusion MAb-188Re could help the graft acceptance by inhibiting T cell proliferation, lowering the expression of type 1 cytokines and elevating the type 2 cytokines produced by PBMC.

  15. Nonequivalence of classical MHC class I loci in ability to direct effective antiviral immunity.

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    Kevin D Pavelko

    2012-02-01

    Full Text Available Structural diversity in the peptide binding sites of the redundant classical MHC antigen presenting molecules is strongly selected in humans and mice. Although the encoded antigen presenting molecules overlap in antigen presenting function, differences in polymorphism at the MHC I A, B and C loci in humans and higher primates indicate these loci are not functionally equivalent. The structural basis of these differences is not known. We hypothesize that classical class I loci differ in their ability to direct effective immunity against intracellular pathogens. Using a picornavirus infection model and chimeric H-2 transgenes, we examined locus specific functional determinants distinguishing the ability of class I sister genes to direct effective anti viral immunity. Whereas, parental FVB and transgenic FVB mice expressing the H-2K(b gene are highly susceptible to persisting Theiler's virus infection within the CNS and subsequent demyelination, mice expressing the D(b transgene clear the virus and are protected from demyelination. Remarkably, animals expressing a chimeric transgene, comprised primarily of K(b but encoding the peptide binding domain of D(b, develop a robust anti viral CTL response yet fail to clear virus and develop significant demyelination. Differences in expression of the chimeric K(bα1α2D(b gene (low and D(b (high in the CNS of infected mice mirror expression levels of their endogenous H-2(q counterparts in FVB mice. These findings demonstrate that locus specific elements other than those specifying peptide binding and T cell receptor interaction can determine ability to clear virus infection. This finding provides a basis for understanding locus-specific differences in MHC polymorphism, characterized best in human populations.

  16. Characterization of a nonclassical class I MHC gene in a reptile, the Galapagos marine iguana (Amblyrhynchus cristatus.

    Directory of Open Access Journals (Sweden)

    Scott Glaberman

    Full Text Available Squamates are a diverse order of vertebrates, representing more than 7,000 species. Yet, descriptions of full-length major histocompatibility complex (MHC genes in this group are nearly absent from the literature, while the number of MHC studies continues to rise in other vertebrate taxa. The lack of basic information about MHC organization in squamates inhibits investigation into the relationship between MHC polymorphism and disease, and leaves a large taxonomic gap in our understanding of amniote MHC evolution. Here, we use both cDNA and genomic sequence data to characterize a class I MHC gene (Amcr-UA from the Galápagos marine iguana, a member of the squamate subfamily Iguaninae. Amcr-UA appears to be functional since it is expressed in the blood and contains many of the conserved peptide-binding residues that are found in classical class I genes of other vertebrates. In addition, comparison of Amcr-UA to homologous sequences from other iguanine species shows that the antigen-binding portion of this gene is under purifying selection, rather than balancing selection, and therefore may have a conserved function. A striking feature of Amcr-UA is that both the cDNA and genomic sequences lack the transmembrane and cytoplasmic domains that are necessary to anchor the class I receptor molecule into the cell membrane, suggesting that the product of this gene is secreted and consequently not involved in classical class I antigen-presentation. The truncated and conserved character of Amcr-UA lead us to define it as a nonclassical gene that is related to the few available squamate class I sequences. However, phylogenetic analysis placed Amcr-UA in a basal position relative to other published classical MHC genes from squamates, suggesting that this gene diverged near the beginning of squamate diversification.

  17. Sequence diversity between class I MHC loci of African native and introduced Bos taurus cattle in Theileria parva endemic regions

    DEFF Research Database (Denmark)

    Obara, Isaiah; Nielsen, Morten; Jeschek, Marie;

    2016-01-01

    There is strong evidence that the immunity induced by live vaccination for control of the protozoan parasite Theileria parva is mediated by class I MHC-restricted CD8+ T cells directed against the schizont stage of the parasite that infects bovine lymphocytes. The functional competency of class I...

  18. Prediction of MHC class II binding affinity using SMM-align, a novel stabilization matrix alignment method

    Directory of Open Access Journals (Sweden)

    Lund Ole

    2007-07-01

    Full Text Available Abstract Background Antigen presenting cells (APCs sample the extra cellular space and present peptides from here to T helper cells, which can be activated if the peptides are of foreign origin. The peptides are presented on the surface of the cells in complex with major histocompatibility class II (MHC II molecules. Identification of peptides that bind MHC II molecules is thus a key step in rational vaccine design and developing methods for accurate prediction of the peptide:MHC interactions play a central role in epitope discovery. The MHC class II binding groove is open at both ends making the correct alignment of a peptide in the binding groove a crucial part of identifying the core of an MHC class II binding motif. Here, we present a novel stabilization matrix alignment method, SMM-align, that allows for direct prediction of peptide:MHC binding affinities. The predictive performance of the method is validated on a large MHC class II benchmark data set covering 14 HLA-DR (human MHC and three mouse H2-IA alleles. Results The predictive performance of the SMM-align method was demonstrated to be superior to that of the Gibbs sampler, TEPITOPE, SVRMHC, and MHCpred methods. Cross validation between peptide data set obtained from different sources demonstrated that direct incorporation of peptide length potentially results in over-fitting of the binding prediction method. Focusing on amino terminal peptide flanking residues (PFR, we demonstrate a consistent gain in predictive performance by favoring binding registers with a minimum PFR length of two amino acids. Visualizing the binding motif as obtained by the SMM-align and TEPITOPE methods highlights a series of fundamental discrepancies between the two predicted motifs. For the DRB1*1302 allele for instance, the TEPITOPE method favors basic amino acids at most anchor positions, whereas the SMM-align method identifies a preference for hydrophobic or neutral amino acids at the anchors. Conclusion

  19. Transcription variants of SLA-7, a swine non classical MHC class I gene.

    Science.gov (United States)

    Hu, Rui; Lemonnier, Gaëtan; Bourneuf, Emmanuelle; Vincent-Naulleau, Silvia; Rogel-Gaillard, Claire

    2011-06-03

    In pig, very little information is available on the non classical class I (Ib) genes of the Major Histocompatibility Complex (MHC) i.e. SLA-6, -7 and -8. Our aim was to focus on the transcription pattern of the SLA-7 gene. RT-PCR experiments were carried out with SLA-7 specific primers targeting either the full coding sequence (CDS) from exon 1 to the 3 prime untranslated region (3UTR) or a partial CDS from exon 4 to the 3UTR. We show that the SLA-7 gene expresses a full length transcript not yet identified that refines annotation of the gene with eight exons instead of seven as initially described from the existing RefSeq RNA. These two RNAs encode molecules that differ in cytoplasmic tail length. In this study, another SLA-7 transcript variant was characterized, which encodes a protein with a shorter alpha 3 domain, as a consequence of a splicing site within exon 4. Surprisingly, a cryptic non canonical GA-AG splicing site is used to generate this transcript variant. An additional SLA-7 variant was also identified in the 3UTR with a splicing site occurring 31 nucleotides downstream to the stop codon. In conclusion, the pig SLA-7 MHC class Ib gene presents a complex transcription pattern with two transcripts encoding various molecules and transcripts that do not alter the CDS and may be subject to post-transcriptional regulation.

  20. Mechanical stress downregulates MHC class I expression on human cancer cell membrane.

    Directory of Open Access Journals (Sweden)

    Rosanna La Rocca

    Full Text Available In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC class I molecules expression on cancer cell membrane compared to different kinds of healthy cells (fibroblasts, macrophages, dendritic and lymphocyte cells was observed, stimulating the cells with forces in the range of nano-newton, and pressures between 1 and 10 bar (1 bar = 100.000 Pascal, depending on the devices used. Moreover, Raman spectroscopy analysis, after mechanical treatment, in the range between 700-1800 cm(-1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased susceptibility to Natural Killer (NK cells cytotoxic recognition.

  1. Mechanical stress downregulates MHC class I expression on human cancer cell membrane.

    Science.gov (United States)

    La Rocca, Rosanna; Tallerico, Rossana; Talib Hassan, Almosawy; Das, Gobind; Lakshmikanth, Tadepally; Tadepally, Lakshmikanth; Matteucci, Marco; Liberale, Carlo; Mesuraca, Maria; Scumaci, Domenica; Gentile, Francesco; Cojoc, Gheorghe; Perozziello, Gerardo; Ammendolia, Antonio; Gallo, Adriana; Kärre, Klas; Cuda, Giovanni; Candeloro, Patrizio; Di Fabrizio, Enzo; Carbone, Ennio

    2014-01-01

    In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells (fibroblasts, macrophages, dendritic and lymphocyte cells) was observed, stimulating the cells with forces in the range of nano-newton, and pressures between 1 and 10 bar (1 bar = 100.000 Pascal), depending on the devices used. Moreover, Raman spectroscopy analysis, after mechanical treatment, in the range between 700-1800 cm(-1), indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased susceptibility to Natural Killer (NK) cells cytotoxic recognition.

  2. Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane

    KAUST Repository

    La Rocca, Rosanna

    2014-12-26

    In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells (fibroblasts, macrophages, dendritic and lymphocyte cells) was observed, stimulating the cells with forces in the range of nano-newton, and pressures between 1 and 10 bar (1 bar = 100.000 Pascal), depending on the devices used. Moreover, Raman spectroscopy analysis, after mechanical treatment, in the range between 700–1800 cm−1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased susceptibility to Natural Killer (NK) cells cytotoxic recognition.

  3. Evolution of innate-like T cells and their selection by MHC class I-like molecules.

    Science.gov (United States)

    Edholm, Eva-Stina; Banach, Maureen; Robert, Jacques

    2016-08-01

    Until recently, major histocompatibility complex (MHC) class I-like-restricted innate-like αβT (iT) cells expressing an invariant or semi-invariant T cell receptor (TCR) repertoire were thought to be a recent evolutionary acquisition restricted to mammals. However, molecular and functional studies in Xenopus laevis have demonstrated that iT cells, defined as MHC class I-like-restricted innate-like αβT cells with a semi-invariant TCR, are evolutionarily conserved and prominent from early development in amphibians. As these iT cells lack the specificity conferred by conventional αβ TCRs, it is generally considered that they are specialized to recognize conserved antigens equivalent to pathogen-associated molecular patterns. Thus, one advantage offered by the MHC class I-like iT cell-based recognition system is that it can be adapted to a common pathogen and function on the basis of a relatively small number of T cells. Although iT cells have only been functionally described in mammals and amphibians, the identification of non-classical MHC/MHC class I-like genes in other groups of endothermic and ectothermic vertebrates suggests that iT cells have a broader phylogenetic distribution than previously envisioned. In this review, we discuss the possible role of iT cells during the emergence of the jawed vertebrate adaptive immune system. PMID:27368412

  4. Trans-species polymorphism and selection in the MHC class II DRA genes of domestic sheep.

    Directory of Open Access Journals (Sweden)

    Keith T Ballingall

    Full Text Available Highly polymorphic genes with central roles in lymphocyte mediated immune surveillance are grouped together in the major histocompatibility complex (MHC in higher vertebrates. Generally, across vertebrate species the class II MHC DRA gene is highly conserved with only limited allelic variation. Here however, we provide evidence of trans-species polymorphism at the DRA locus in domestic sheep (Ovis aries. We describe variation at the Ovar-DRA locus that is far in excess of anything described in other vertebrate species. The divergent DRA allele (Ovar-DRA*0201 differs from the sheep reference sequences by 20 nucleotides, 12 of which appear non-synonymous. Furthermore, DRA*0201 is paired with an equally divergent DRB1 allele (Ovar-DRB1*0901, which is consistent with an independent evolutionary history for the DR sub-region within this MHC haplotype. No recombination was observed between the divergent DRA and B genes in a range of breeds and typical levels of MHC class II DR protein expression were detected at the surface of leukocyte populations obtained from animals homozygous for the DRA*0201, DRB1*0901 haplotype. Bayesian phylogenetic analysis groups Ovar-DRA*0201 with DRA sequences derived from species within the Oryx and Alcelaphus genera rather than clustering with other ovine and caprine DRA alleles. Tests for Darwinian selection identified 10 positively selected sites on the branch leading to Ovar-DRA*0201, three of which are predicted to be associated with the binding of peptide antigen. As the Ovis, Oryx and Alcelaphus genera have not shared a common ancestor for over 30 million years, the DRA*0201 and DRB1*0901 allelic pair is likely to be of ancient origin and present in the founding population from which all contemporary domestic sheep breeds are derived. The conservation of the integrity of this unusual DR allelic pair suggests some selective advantage which is likely to be associated with the presentation of pathogen antigen to T

  5. Signal transduction by the major histocompatibility complex class I molecule

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Skov, S; Bregenholt, S;

    1999-01-01

    Ligation of cell surface major histocompatibility class I (MHC-I) proteins by antibodies, or by their native counter receptor, the CD8 molecule, mediates transduction of signals into the cells. MHC-I-mediated signaling can lead to both increased and decreased activity of the MHC-I-expressing cell...

  6. Premalignant quiescent melanocytic nevi do not express the MHC class I chain-related protein A Los nevos melanocíticos premalignos quiescentes no expresan la molécula MHC class I chain-related protein A

    Directory of Open Access Journals (Sweden)

    Mercedes B. Fuertes

    2011-08-01

    Full Text Available The MHC class I chain-related protein A (MICA is an inducible molecule almost not expressed by normal cells but strongly up-regulated in tumor cells. MICA-expressing cells are recognized by natural killer (NK cells, CD8+ aßTCR and ?dTCR T lymphocytes through the NKG2D receptor. Engagement of NKG2D by MICA triggers IFN-? secretion and cytotoxicity against malignant cells. Although most solid tumors express MICA and this molecule is a target during immune surveillance against tumors, it has been observed that high grade tumors from different histotypes express low amounts of cell surface MICA due to a metalloprotease- induced shedding. Also, melanomas develop after a complex process of neotransformation of normal melanocytes. However, the expression of MICA in premalignant stages (primary human quiescent melanocytic nevi remains unknown. Here, we assessed expression of MICA by flow cytometry using cell suspensions from 15 primary nevi isolated from 11 patients. When collected material was abundant, cell lysates were prepared and MICA expression was also analyzed by Western blot. We observed that MICA was undetectable in the 15 primary nevi (intradermic, junction, mixed, lentigo and congenital samples as well as in normal skin, benign lesions (seborrheic keratosis, premalignant lesions (actinic keratosis and benign basocellular cancer. Conversely, a primary recently diagnosed melanoma showed intense cell surface MICA. We conclude that the onset of MICA expression is a tightly regulated process that occurs after melanocytes trespass the stage of malignant transformation. Thus, analysis of MICA expression in tissue sections of skin samples may constitute a useful marker to differentiate between benign and malignant nevi.MHC class I chain-related protein A (MICA es una molécula casi ausente en células normales pero sobre-expresada por células tumorales, que promueve el reconocimiento por células citotóxicas naturales (natural killer o NK y por

  7. Complementary DNA sequences encoding the multimammate rat MHC class II DQ α and β chains and cross-species sequence comparison in rodents

    DEFF Research Database (Denmark)

    Goüy de Bellocq, J; Leirs, H

    2009-01-01

    Sequences of the complete open reading frame (ORF) for rodents major histocompatibility complex (MHC) class II genes are rare. Multimammate rat (Mastomys natalensis) complementary DNA (cDNA) encoding the alpha and beta chains of MHC class II DQ gene was cloned from a rapid amplifications of c...

  8. Use of "one-pot, mix-and-read" peptide-MHC class I tetramers and predictive algorithms to improve detection of cytotoxic T lymphocyte responses in cattle

    DEFF Research Database (Denmark)

    Svitek, Nicholas; Hansen, Andreas Martin; Steinaa, Lucilla;

    2014-01-01

    LA) and recombinant bovine beta 2-microglobulin from which p-MHC class I tetramers can be derived in similar to 48 h. We validated a set of p-MHC class I tetramers against a panel of CTL lines specific to seven epitopes on five different antigens of Theileria parva, a protozoan pathogen causing the lethal bovine...

  9. Frequent lack of translation of antigen presentation-associated molecules MHC class I, CD1a and Beta(2)-microglobulin in Reed-Sternberg cells

    NARCIS (Netherlands)

    van den Berg, A.; Visser, L; Eberwine, J; Dadvand, L; Poppema, S

    2000-01-01

    Epstein-Barr virus (EBV) is present in Reed-Sternberg (RS) cells of a substantial proportion of Hodgkin's lymphoma cases. Most EBV-positive cases are also MHC class I-positive, whereas the majority of EBV-negative cases lack detectable levels of MHC class I expression. Application of the SAGE techni

  10. ZAP-70 and p72syk are signaling response elements through MHC class II molecules

    DEFF Research Database (Denmark)

    Kanner, S B; Grosmaire, L S; Blake, J;

    1995-01-01

    -activated human T-cells. In both tonsillar B-lymphocytes and B-cell leukemia lines, p72syk was rapidly phosphorylated on tyrosine residues following HLA-DR cross-linking. Tyrosine phosphorylation of p72syk induced through ligation of either the B-cell antigen receptor or class II molecules was potently inhibited...... intracellular calcium. Similar responses have been observed in B-cells following stimulation of MHC class II molecules, including the increased production of intracellular cAMP. In this report, we demonstrate that the ZAP-70 tyrosine kinase is a responsive signaling element following cross-linking of HLA-DR in...... antibody induced receptor ligation, bacterial superantigen (SEA and SEB) treatment of HLA-DR+ T-cells stimulated ZAP-70 tyrosine phosphorylation, consistent with class II transmembrane signaling by ligation of HLA-DR and V beta in cis. Modulation of the TCR/CD3 led to abrogation of class II induced ZAP-70...

  11. Efficient vaccine against pandemic influenza: combining DNA vaccination and targeted delivery to MHC class II molecules.

    Science.gov (United States)

    Grødeland, Gunnveig; Bogen, Bjarne

    2015-06-01

    There are two major limitations to vaccine preparedness in the event of devastating influenza pandemics: the time needed to generate a vaccine and rapid generation of sufficient amounts. DNA vaccination could represent a solution to these problems, but efficacy needs to be enhanced. In a separate line of research, it has been established that targeting of vaccine molecules to antigen-presenting cells enhances immune responses. We have combined the two principles by constructing DNA vaccines that encode bivalent fusion proteins; these target hemagglutinin to MHC class II molecules on antigen-presenting cells. Such DNA vaccines rapidly induce hemagglutinin-specific antibodies and T cell responses in immunized mice. Responses are long-lasting and protect mice against challenge with influenza virus. In a pandemic situation, targeted DNA vaccines could be produced and tested within a month. The novel DNA vaccines could represent a solution to pandemic preparedness in the advent of novel influenza pandemics.

  12. Exposing the specific roles of the invariant chain isoforms in shaping the MHC class II peptidome

    Directory of Open Access Journals (Sweden)

    Jean-Simon eFortin

    2013-12-01

    Full Text Available The peptide repertoire (peptidome associated with MHC class II molecules (MHCIIs is influenced by the polymorphic nature of the peptide binding groove but also by cell-intrinsic factors. The invariant chain (Ii chaperones MHCIIs, affecting their folding and trafficking. Recent discoveries relating to Ii functions have provided insights as to how it edits the MHCII peptidome. In humans, the Ii gene encodes four different isoforms for which structure-function analyses have highlighted common properties but also some non-redundant roles. Another layer of complexity arises from the fact that Ii heterotrimerizes, a characteristic that has the potential to affect the maturation of associated MHCIIs in many different ways, depending on the isoform combinations. Here, we emphasize the peptide editing properties of Ii and discuss the impact of the various isoforms on the MHCII peptidome.

  13. Cross-presentation of cell-associated antigens by MHC class I in dendritic cell subsets

    Directory of Open Access Journals (Sweden)

    Enric eGutiérrez-Martínez

    2015-07-01

    Full Text Available Dendritic cells have the unique ability to pick up dead cells carrying antigens in tissue and migrate to the lymph nodes where they can cross-present cell-associated antigens by MHC class I to CD8+ T cells. There is strong in vivo evidence that the mouse XCR1+ dendritic cells subset acts as a key player in this process. The intracellular processes underlying cross-presentation remain controversial and several pathways have been proposed. Indeed, a wide number of studies have addressed the cellular process of cross-presentation in vitro using a variety of sources of antigen and antigen presenting cells. Here we review the in vivo and in vitro evidence supporting the current mechanistic models and disscuss their physiological relevance to the cross-presentation of cell-associated antigens by dendritic cells subsets

  14. THERMODYNAMICS OF PEPTIDE-MHC CLASS II INTERACTIONS: NOT ALL COMPLEXES ARE CREATED EQUAL

    Directory of Open Access Journals (Sweden)

    Andrea eFerrante

    2013-10-01

    Full Text Available The adaptive immune response begins when CD4+ T cells recognize antigenic peptides bound to class II molecules of the Major Histocompatibility Complex (MHCII. The interaction between peptides and MHCII has been historically interpreted as a rigid docking event. However, this model has been challenged by the evidence that conformational flexibility plays an important role in peptide-MHCII complex formation. Thermodynamic analysis of the binding reaction suggests a model of complexation in which the physical-chemical nature of the peptide determines the variability in flexibility of the substates in the peptide-MHC conformational ensemble. This review discusses our understanding of the correlation between thermodynamics of peptide binding and structural features of the resulting complex as well as their impact on HLA-DM activity and on our ability to predict MHCII-restricted epitopes.

  15. Characterization of monoclonal antibodies against MHC class II-associated p41 invariant chain fragment

    International Nuclear Information System (INIS)

    Mouse monoclonal antibodies directed against human MHC class II-associated p41 invariant chain fragment have been generated. Mice were immunized with human recombinant Ii-isoform p26. For hybridoma production mouse splenocytes and myeloma cells were fused. Hybridoma cells were screened using ELISA and immunoblotting. Three cell lines (42B10, 42G11 and 43C8) were used for production of specific antibodies, which reacted with p41 fragment and did not bind to cathepsins L or S or their proenyzmes. As primary antibody for immunofluorescence staining of lymph node tissue sections clone 2C12 MAb was selected. Specific localization of p41 fragment in certain cells in lymph nodes was observed. (author)

  16. MHC class II genes in the European badger (Meles meles) : characterization, patterns of variation, and transcription analysis

    NARCIS (Netherlands)

    Sin, Yung Wa; Dugdale, Hannah L.; Newman, Chris; Macdonald, David W.; Burke, Terry

    2012-01-01

    The major histocompatibility complex (MHC) comprises many genes, some of which are polymorphic with numerous alleles. Sequence variation among alleles is most pronounced in exon 2 of the class II genes, which encodes the alpha 1 and beta 1 domains that form the antigen-binding site (ABS) for the pre

  17. MHC class II-associated proteins in B-cell exosomes and potential functional implications for exosome biogenesis.

    NARCIS (Netherlands)

    Buschow, S.I.; Balkom, B.W.M. van; Aalberts, M.; Heck, A.J.R. van; Wauben, M.; Stoorvogel, W.

    2010-01-01

    Professional antigen-presenting cells secrete major histocompatibility complex class II (MHC II) carrying exosomes with unclear physiological function(s). Exosomes are first generated as the intraluminal vesicles (ILVs) of a specific type of multivesicular body, and are then secreted by fusion of th

  18. Self-peptides with intermediate capacity to bind and stabilize MHC class I molecules may be immunogenic

    DEFF Research Database (Denmark)

    Andersen, M L M; Ruhwald, Morten; Nissen, M H;

    2003-01-01

    Thirty self-peptides were selected on the basis of their predicted binding to H-2b molecules. The binding of peptides was ascertained experimentally by biochemical (KD measurements) and cellular [major histocompatibility complex class I (MHC-I) stabilization] assays. A weak, but significant, corr...

  19. Possible assortment of a1 and a2 region gene segments in human MHC class I molecules.

    Science.gov (United States)

    Johnson, G; Wu, T T

    1998-06-01

    Using pair-wise comparison of aligned nucleotide sequences of distinct and complete human MHC class I molecules, we have constructed triangular tables to study the similarities and differences of various a1 (exon 2) and a2 (exon 3) region sequences. There are two HLA-A (A*6901 and A*6601) and 13 HLA-B (B*4201, B*8101, B*4102, B*4801, B*4007, B*4001, B*4802, Dw53, B*4406, B*4402, B*3901, B*1514 and B*3702) sequences that have identical a1 sequences with other known MHC class I molecules, while their a2 sequences are the same as those of different ones. Of these 15, A*6901, B*4001 and B*4802 have previously been suggested as the results of recombination between A*6801 and A*0201, B*4101 and B*8101, and B*4801 and B*3501, respectively. However, many other sequences can also be used to generate them by recombination. Furthermore, their reciprocal products have never been identified. Thus, gene conversion has subsequently been suggested as an alternative. Another possible genetic mechanism for generating these nucleotide sequence similarities can be assortment, or that some gene segments can be duplicated or multiplicated to be used in different human MHC class I molecules. Interestingly, this genetic mechanism is probably absent for the generation of different mouse MHC class I molecules.

  20. NN-align. An artificial neural network-based alignment algorithm for MHC class II peptide binding prediction

    DEFF Research Database (Denmark)

    Nielsen, Morten; Lund, Ole

    2009-01-01

    this binding event. RESULTS: Here, we present a novel artificial neural network-based method, NN-align that allows for simultaneous identification of the MHC class II binding core and binding affinity. NN-align is trained using a novel training algorithm that allows for correction of bias in the training data...

  1. Domain structures and molecular evolution of class I and class II major histocompatibility gene complex (MHC) products deduced from amino acid and nucleotide sequence homologies

    Science.gov (United States)

    Ohnishi, Koji

    1984-12-01

    Domain structures of class I and class II MHC products were analyzed from a viewpoint of amino acid and nucleotide sequence homologies. Alignment statistics revealed that class I (transplantation) antigen H chains consist of four mutually homologous domains, and that class II (HLA-DR) antigen β and α chains are both composed of three mutually homologous ones. The N-terminal three and two domains of class I and class II (both β and α) gene products, respectively, all of which being ˜90 residues long, were concluded to be homologous to β2-microglobulin (β2M). The membraneembedded C-terminal shorter domains of these MHC products were also found to be homologous to one another and to the third domain of class I H chains. Class I H chains were found to be more closely related to class II α chains than to class II β chains. Based on these findings, an exon duplication history from a common ancestral gene encoding a β2M-like primodial protein of one-domain-length up to the contemporary MHC products was proposed.

  2. Direct binding of autoimmune disease related T cell epitopes to purified Lewis rat MHC class II molecules

    DEFF Research Database (Denmark)

    Joosten, I; Wauben, M H; Holewijn, M C;

    1994-01-01

    must be able to assess peptide-MHC interactions. Several well described autoimmune disease models exist in the Lewis rat and thus this particular rat strain provides a good model system to study the effect of competitor peptides. So far no information has been available on the peptide binding...... characteristics of the Lewis rat MHC class II RT1.B1 molecule. We have now developed a biochemical binding assay which enables competition studies in which the relative MHC binding affinity of a set of non-labelled peptides can be assessed while employing detection of biotinylated marker peptides...... by chemiluminescence. The assay is sensitive and specific. We have used this assay to determine the binding characteristics of several disease associated T cell determinants and their sequence analogues in the Lewis rat. Notably, most of the autoimmune disease associated peptide sequences tested were found...

  3. GPS-MBA: computational analysis of MHC class II epitopes in type 1 diabetes.

    Science.gov (United States)

    Cai, Ruikun; Liu, Zexian; Ren, Jian; Ma, Chuang; Gao, Tianshun; Zhou, Yanhong; Yang, Qing; Xue, Yu

    2012-01-01

    As a severe chronic metabolic disease and autoimmune disorder, type 1 diabetes (T1D) affects millions of people world-wide. Recent advances in antigen-based immunotherapy have provided a great opportunity for further treating T1D with a high degree of selectivity. It is reported that MHC class II I-A(g7) in the non-obese diabetic (NOD) mouse and human HLA-DQ8 are strongly linked to susceptibility to T1D. Thus, the identification of new I-A(g7) and HLA-DQ8 epitopes would be of great help to further experimental and biomedical manipulation efforts. In this study, a novel GPS-MBA (MHC Binding Analyzer) software package was developed for the prediction of I-A(g7) and HLA-DQ8 epitopes. Using experimentally identified epitopes as the training data sets, a previously developed GPS (Group-based Prediction System) algorithm was adopted and improved. By extensive evaluation and comparison, the GPS-MBA performance was found to be much better than other tools of this type. With this powerful tool, we predicted a number of potentially new I-A(g7) and HLA-DQ8 epitopes. Furthermore, we designed a T1D epitope database (TEDB) for all of the experimentally identified and predicted T1D-associated epitopes. Taken together, this computational prediction result and analysis provides a starting point for further experimental considerations, and GPS-MBA is demonstrated to be a useful tool for generating starting information for experimentalists. The GPS-MBA is freely accessible for academic researchers at: http://mba.biocuckoo.org.

  4. Identification of MHC class I associated peptides. Development of sensitive mass spectrometric sequence analysis techniques

    NARCIS (Netherlands)

    de Jong APJM; van der Heeft E; ten Hove GJ; van Gaans-van den Brink JAM; van Els CACM; LOC; LVM

    1996-01-01

    Betreft de ontwikkeling van gevoelige microkolom HPLC-ESI/MS methoden en technieken voor de analyse van MHC klasse I geassocieerde antigeenpeptiden. De analyse bestaat uit de identificatie van T-cel stimulerende peptiden in MHC elutiemengsels van geinfecteerde celkweekculturen gevolgd door de bepal

  5. Evolution of MHC class I genes in the European badger (Meles meles)

    NARCIS (Netherlands)

    Sin, Yung Wa; Dugdale, Hannah L.; Newman, Chris; Macdonald, David W.; Burke, Terry

    2012-01-01

    The major histocompatibility complex (MHC) plays a central role in the adaptive immune system and provides a good model with which to understand the evolutionary processes underlying functional genes. Trans-species polymorphism and orthology are both commonly found in MHC genes; however, mammalian M

  6. TLR-induced activation of Btk- Role for endosomal MHC class Ⅱ molecules revealed

    Institute of Scientific and Technical Information of China (English)

    Joan Ni Gabhann; Caroline A Jefferies

    2011-01-01

    @@ MHC molecules have been shown to play key roles in the immune system including regulating T-cell repertoire development through the process of positive and negative selection.MHC molecules also function to bridge the innate and adaptive immune system through the presentation of processed antigenic peptides to T-cells.

  7. Molecular requirements for MHC class II alpha-chain engagement and allelic discrimination by the bacterial superantigen streptococcal pyrogenic exotoxin C.

    Science.gov (United States)

    Kasper, Katherine J; Xi, Wang; Rahman, A K M Nur-Ur; Nooh, Mohammed M; Kotb, Malak; Sundberg, Eric J; Madrenas, Joaquín; McCormick, John K

    2008-09-01

    Superantigens (SAgs) are microbial toxins that bind to both TCR beta-chain variable domains (Vbetas) and MHC class II molecules, resulting in the activation of T cells in a Vbeta-specific manner. It is now well established that different isoforms of MHC II molecules can play a significant role in the immune response to bacterial SAgs. In this work, using directed mutational studies in conjunction with functional analyses, we provide a complete functional map of the low-affinity MHC II alpha-chain binding interface of the SAg streptococcal pyrogenic exotoxin C (SpeC) and identify a functional epitope in the beta-barrel domain that is required for the activation of T cells. Using cell lines that exclusively express individual MHC II isoforms, our studies provide a molecular basis for the selectivity of SpeC-MHC II recognition, and provide one mechanism by how SAgs are capable of distinguishing between different MHC II alleles.

  8. Toward a network model of MHC class II-restricted antigen processing

    Directory of Open Access Journals (Sweden)

    Laurence C Eisenlohr

    2013-12-01

    Full Text Available The standard model of Major Histocompatibility Complex class II (MHCII-restricted antigen processing depicts a straightforward, linear pathway: Internalized antigens are converted into peptides that load in a chaperone dependent manner onto nascent MHCII in the late endosome, the complexes subsequently trafficking to the cell surface for recognition by CD4+ T cells (TCD4+. Several variations on this theme, both moderate and radical, have come to light but these alternatives have remained peripheral, the conventional pathway generally presumed to be the primary driver of TCD4+ responses. Here we continue to press for the conceptual repositioning of these alternatives toward the center while proposing that MHCII processing be thought of less in terms of discrete pathways and more in terms of a network whose major and minor conduits are variable depending upon many factors, including the epitope, the nature of the antigen, the source of the antigen, and the identity of the antigen-presenting cell.

  9. MHC class I-related molecule, MR1, and mucosal-associated invariant T cells.

    Science.gov (United States)

    Franciszkiewicz, Katarzyna; Salou, Marion; Legoux, Francois; Zhou, Qian; Cui, Yue; Bessoles, Stéphanie; Lantz, Olivier

    2016-07-01

    The MHC-related 1, MR1, molecule presents a new class of microbial antigens (derivatives of the riboflavin [Vitamin B2] biosynthesis pathway) to mucosal-associated invariant T (MAIT) cells. This raises many questions regarding antigens loading and intracellular trafficking of the MR1/ligand complexes. The MR1/MAIT field is also important because MAIT cells are very abundant in humans and their frequency is modified in many infectious and non-infectious diseases. Both MR1 and the invariant TCRα chain expressed by MAIT cells are strikingly conserved among species, indicating important functions. Riboflavin is synthesized by plants and most bacteria and yeasts but not animals, and its precursor derivatives activating MAIT cells are short-lived unless bound to MR1. The recognition of MR1 loaded with these compounds is therefore an exquisite manner to detect invasive bacteria. Herein, we provide an historical perspective of the field before describing the main characteristics of MR1, its ligands, and the few available data regarding its cellular biology. We then summarize the current knowledge of MAIT cell differentiation and discuss the definition of MAIT cells in comparison to related subsets. Finally, we describe the phenotype and effector activities of MAIT cells. PMID:27319347

  10. Expression, Purification and Characterization of Ricin vectors used for exogenous antigen delivery into the MHC Class I presentation pathway

    Directory of Open Access Journals (Sweden)

    Smith Daniel C.

    2003-01-01

    Full Text Available Disarmed versions of the cytotoxin ricin can deliver fused peptides into target cells leading to MHC class I-restricted antigen presentation [Smith et al. J Immunol 2002; 169:99-107]. The ricin delivery vector must contain an attenuated catalytic domain to prevent target cell death, and the fused peptide epitope must remain intact for delivery and functional loading to MHC class I molecules. Expression in E. coli and purification by cation exchange chromatography of the fusion protein is described. Before used for delivery, the activity of the vector must be characterized in vitro, via an N-glycosidase assay, and in vivo, by a cytotoxicity assay. The presence of an intact epitope must be confirmed using mass spectrometry by comparing the actual mass with the predicted mass.

  11. A novel HURRAH protocol reveals high numbers of monomorphic MHC class II loci and two asymmetric multi-locus haplotypes in the Pere David's deer.

    Directory of Open Access Journals (Sweden)

    Qiu-Hong Wan

    Full Text Available The Père David's deer is a highly inbred, but recovered, species, making it interesting to consider their adaptive molecular evolution from an immunological perspective. Prior to this study, genomic sequencing was the only method for isolating all functional MHC genes within a certain species. Here, we report a novel protocol for isolating MHC class II loci from a species, and its use to investigate the adaptive evolution of this endangered deer at the level of multi-locus haplotypes. This protocol was designated "HURRAH" based on its various steps and used to estimate the total number of MHC class II loci. We confirmed the validity of this novel protocol in the giant panda and then used it to examine the Père David's deer. Our results revealed that the Père David's deer possesses nine MHC class II loci and therefore has more functional MHC class II loci than the eight genome-sequenced mammals for which full MHC data are currently available. This could potentially account at least in part for the strong survival ability of this species in the face of severe bottlenecking. The results from the HURRAH protocol also revealed that: (1 All of the identified MHC class II loci were monomorphic at their antigen-binding regions, although DRA was dimorphic at its cytoplasmic tail; and (2 these genes constituted two asymmetric functional MHC class II multi-locus haplotypes: DRA1*01 ∼ DRB1 ∼ DRB3 ∼ DQA1 ∼ DQB2 (H1 and DRA1*02 ∼ DRB2 ∼ DRB4 ∼ DQA2 ∼ DQB1 (H2. The latter finding indicates that the current members of the deer species have lost the powerful ancestral MHC class II haplotypes of nine or more loci, and have instead fixed two relatively weak haplotypes containing five genes. As a result, the Père David's deer are currently at risk for increased susceptibility to infectious pathogens.

  12. The activation threshold of CD4+ T cells is defined by TCR/peptide-MHC class II interactions in the thymic medulla.

    Science.gov (United States)

    Stephen, Tom Li; Tikhonova, Anastasia; Riberdy, Janice M; Laufer, Terri M

    2009-11-01

    Immature thymocytes that are positively selected based upon their response to self-peptide-MHC complexes develop into mature T cells that are not overtly reactive to those same complexes. Developmental tuning is the active process through which TCR-associated signaling pathways of single-positive thymocytes are attenuated to respond appropriately to the peptide-MHC molecules that will be encountered in the periphery. In this study, we explore the mechanisms that regulate the tuning of CD4(+) single-positive T cells to MHC class II encountered in the thymic medulla. Experiments with murine BM chimeras demonstrate that tuning can be mediated by MHC class II expressed by either thymic medullary epithelial cells or thymic dendritic cells. Tuning does not require the engagement of CD4 by MHC class II on stromal cells. Rather, it is mediated by interactions between MHC class II and the TCR. To understand the molecular changes that distinguish immature hyperactive T cells from tuned mature CD4(+) T cells, we compared their responses to TCR stimulation. The altered response of mature CD4 single-positive thymocytes is characterized by the inhibition of ERK activation by low-affinity self-ligands and increased expression of the inhibitory tyrosine phosphatase SHP-1. Thus, persistent TCR engagement by peptide-MHC class II on thymic medullary stroma inhibits reactivity to self-Ags and prevents autoreactivity in the mature repertoire.

  13. MHC class I chain-related protein A antibodies and shedding are associated with the progression of multiple myeloma

    OpenAIRE

    Jinushi, Masahisa; Vanneman, Matthew; Munshi, Nikhil C.; Tai, Yu-Tzu; Prabhala, Rao H.; Ritz, Jerome; Neuberg, Donna; Anderson, Kenneth C; Carrasco, Daniel Ruben; Dranoff, Glenn

    2008-01-01

    Monoclonal gammopathy of undetermined significance (MGUS) is a common disorder of aging and a precursor lesion to full-blown multiple myeloma (MM). The mechanisms underlying the progression from MGUS to MM are incompletely understood but include the suppression of innate and adaptive antitumor immunity. Here, we demonstrate that NKG2D, an activating receptor on natural killer (NK) cells, CD8+ T lymphocytes, and MHC class I chain-related protein A (MICA), an NKG2D ligand induced in malignant p...

  14. MHC class I and class II phenotype, gene, and haplotype frequencies in Greeks using molecular typing data.

    Science.gov (United States)

    Papassavas, E C; Spyropoulou-Vlachou, M; Papassavas, A C; Schipper, R F; Doxiadis, I N; Stavropoulos-Giokas, C

    2000-06-01

    In the present study, DNA typing for HLA-A, C, B, DRB1, DRB3, DRB4, DRB5, DQA1, DQB1, and DPB1 was performed for 246 healthy, unrelated Greek volunteers of 20-59 years of age. Phenotype, genotype frequencies, Hardy-Weinberg equilibrium fit, and 3-locus haplotype frequencies for HLA-A, C, B, HLA-A, B, DRB1, HLA-DRB1, DQA1, DQB1, and HLA-DRB1, DQB1, DPB1 were calculated. Furthermore, linkage disequilibrium, deltas, relative deltas and p-values for significance of the deltas were defined. The population studied is in Hardy-Weinberg equilibrium, and many MHC haplotypes are in linkage disequilibrium. The most frequent specificities were HLA-A*02 (phenotype frequency = 44.3%) followed by HLA-A*24 (27.2%), HLA-B*51 (28.5%), HLA-B*18 (26.8%) and HLA-B*35 (26.4%) and HLA-Cw*04 (30.1%) and HLA-Cw*12 (26.8%). The most frequent MHC class II alleles were HLA-DRB1*1104 (34.1%), HLA-DQB1*0301 (54.5%) and HLA-DPB1*0401 with a phenotype frequency of 59.8%. The most prominent HLA-A, C, B haplotypes were HLA-A*24, Cw*04, B*35, and HLA-A*02, Cw*04, B*35, each of them observed in 21/246 individuals. The most frequent HLA-A, B, DRB1 haplotype was HLA-A*02, B*18, DRB1*1104 seen in 20/246 individuals, while the haplotype HLA-DRB1*1104, DQB1*0301, DPB1*0401 was found in 49/246 individuals. Finally, the haplotype DRB1*1104, DQA1*0501, DQB1*0301 was observed in 83/246 individuals. These results can be used for the estimation of the probability of finding a suitable haplotypically identical related or unrelated stem cell donor for patients of Greek ancestry. In addition, they can be used for HLA and disease association studies, genetic distance studies in the Balkan and Mediterranean area, paternity cases, and matching probability calculations for the optimal allocation of kidneys in Greece.

  15. Expression of the multiple sclerosis-associated MHC class II Allele HLA-DRB1*1501 is regulated by vitamin D.

    Directory of Open Access Journals (Sweden)

    Sreeram V Ramagopalan

    2009-02-01

    Full Text Available Multiple sclerosis (MS is a complex trait in which allelic variation in the MHC class II region exerts the single strongest effect on genetic risk. Epidemiological data in MS provide strong evidence that environmental factors act at a population level to influence the unusual geographical distribution of this disease. Growing evidence implicates sunlight or vitamin D as a key environmental factor in aetiology. We hypothesised that this environmental candidate might interact with inherited factors and sought responsive regulatory elements in the MHC class II region. Sequence analysis localised a single MHC vitamin D response element (VDRE to the promoter region of HLA-DRB1. Sequencing of this promoter in greater than 1,000 chromosomes from HLA-DRB1 homozygotes showed absolute conservation of this putative VDRE on HLA-DRB1*15 haplotypes. In contrast, there was striking variation among non-MS-associated haplotypes. Electrophoretic mobility shift assays showed specific recruitment of vitamin D receptor to the VDRE in the HLA-DRB1*15 promoter, confirmed by chromatin immunoprecipitation experiments using lymphoblastoid cells homozygous for HLA-DRB1*15. Transient transfection using a luciferase reporter assay showed a functional role for this VDRE. B cells transiently transfected with the HLA-DRB1*15 gene promoter showed increased expression on stimulation with 1,25-dihydroxyvitamin D3 (P = 0.002 that was lost both on deletion of the VDRE or with the homologous "VDRE" sequence found in non-MS-associated HLA-DRB1 haplotypes. Flow cytometric analysis showed a specific increase in the cell surface expression of HLA-DRB1 upon addition of vitamin D only in HLA-DRB1*15 bearing lymphoblastoid cells. This study further implicates vitamin D as a strong environmental candidate in MS by demonstrating direct functional interaction with the major locus determining genetic susceptibility. These findings support a connection between the main epidemiological and

  16. AIDS-protective HLA-B*27/B*57 and chimpanzee MHC class I molecules target analogous conserved areas of HIV-1/SIVcpz

    OpenAIRE

    de Groot, Natasja G.; Corrine M C Heijmans; Zoet, Yvonne M.; de Ru, Arnoud H.; Verreck, Frank A.; van Veelen, Peter A.; Drijfhout, Jan W; Doxiadis, Gaby G M; Remarque, Edmond J.; Doxiadis, Ilias I. N.; van Rood, Jon J.; Koning, Frits; Bontrop, Ronald E

    2010-01-01

    In the absence of treatment, most HIV-1-infected humans develop AIDS. However, a minority are long-term nonprogressors, and resistance is associated with the presence of particular HLA-B*27/B*57 molecules. In contrast, most HIV-1-infected chimpanzees do not contract AIDS. In comparison with humans, chimpanzees experienced an ancient selective sweep affecting the MHC class I repertoire. We have determined the peptide-binding properties of frequent chimpanzee MHC class I molecules, and show tha...

  17. Endoplasmic reticulum aminopeptidase 1 (ERAP1) trims MHC class I-presented peptides in vivo and plays an important role in immunodominance

    OpenAIRE

    Ian A York; Brehm, Michael A.; Zendzian, Sophia; Towne, Charles F.; Rock, Kenneth L.

    2006-01-01

    CD8+ T cells respond to short peptides bound to MHC class I molecules. Although most antigenic proteins contain many sequences that could bind to MHC class I, few of these peptides actually stimulate CD8+ T cell responses. Moreover, the T cell responses that are generated often follow a very reproducible hierarchy to different peptides for reasons that are poorly understood. We find that the loss of a single enzyme, endoplasmic reticulum aminopeptidase 1 (ERAP1), in the antigen-processing pat...

  18. Characterization of the Antigen Processing Machinery and Endogenous Peptide Presentation of a Bat MHC Class I Molecule.

    Science.gov (United States)

    Wynne, James W; Woon, Amanda P; Dudek, Nadine L; Croft, Nathan P; Ng, Justin H J; Baker, Michelle L; Wang, Lin-Fa; Purcell, Anthony W

    2016-06-01

    Bats are a major reservoir of emerging and re-emerging infectious diseases, including severe acute respiratory syndrome-like coronaviruses, henipaviruses, and Ebola virus. Although highly pathogenic to their spillover hosts, bats harbor these viruses, and a large number of other viruses, with little or no clinical signs of disease. How bats asymptomatically coexist with these viruses is unknown. In particular, little is known about bat adaptive immunity, and the presence of functional MHC molecules is mostly inferred from recently described genomes. In this study, we used an affinity purification/mass spectrometry approach to demonstrate that a bat MHC class I molecule, Ptal-N*01:01, binds antigenic peptides and associates with peptide-loading complex components. We identified several bat MHC class I-binding partners, including calnexin, calreticulin, protein disulfide isomerase A3, tapasin, TAP1, and TAP2. Additionally, endogenous peptide ligands isolated from Ptal-N*01:01 displayed a relatively broad length distribution and an unusual preference for a C-terminal proline residue. Finally, we demonstrate that this preference for C-terminal proline residues was observed in Hendra virus-derived peptides presented by Ptal-N*01:01 on the surface of infected cells. To our knowledge, this is the first study to identify endogenous and viral MHC class I ligands for any bat species and, as such, provides an important avenue for monitoring and development of vaccines against major bat-borne viruses both in the reservoir and spillover hosts. Additionally, it will provide a foundation to understand the role of adaptive immunity in bat antiviral responses. PMID:27183594

  19. Bacterial Superantigens Promote Acute Nasopharyngeal Infection by Streptococcus pyogenes in a Human MHC Class II-Dependent Manner

    Science.gov (United States)

    Kasper, Katherine J.; Zeppa, Joseph J.; Wakabayashi, Adrienne T.; Xu, Stacey X.; Mazzuca, Delfina M.; Welch, Ian; Baroja, Miren L.; Kotb, Malak; Cairns, Ewa; Cleary, P. Patrick; Haeryfar, S. M. Mansour; McCormick, John K.

    2014-01-01

    Establishing the genetic determinants of niche adaptation by microbial pathogens to specific hosts is important for the management and control of infectious disease. Streptococcus pyogenes is a globally prominent human-specific bacterial pathogen that secretes superantigens (SAgs) as ‘trademark’ virulence factors. SAgs function to force the activation of T lymphocytes through direct binding to lateral surfaces of T cell receptors and class II major histocompatibility complex (MHC-II) molecules. S. pyogenes invariably encodes multiple SAgs, often within putative mobile genetic elements, and although SAgs are documented virulence factors for diseases such as scarlet fever and the streptococcal toxic shock syndrome (STSS), how these exotoxins contribute to the fitness and evolution of S. pyogenes is unknown. Here we show that acute infection in the nasopharynx is dependent upon both bacterial SAgs and host MHC-II molecules. S. pyogenes was rapidly cleared from the nasal cavity of wild-type C57BL/6 (B6) mice, whereas infection was enhanced up to ∼10,000-fold in B6 mice that express human MHC-II. This phenotype required the SpeA superantigen, and vaccination with an MHC –II binding mutant toxoid of SpeA dramatically inhibited infection. Our findings indicate that streptococcal SAgs are critical for the establishment of nasopharyngeal infection, thus providing an explanation as to why S. pyogenes produces these potent toxins. This work also highlights that SAg redundancy exists to avoid host anti-SAg humoral immune responses and to potentially overcome host MHC-II polymorphisms. PMID:24875883

  20. Characterization of bovine MHC class II DRB3 diversity in South American Holstein cattle populations.

    Science.gov (United States)

    Takeshima, S-N; Giovambattista, G; Okimoto, N; Matsumoto, Y; Rogberg-Muñoz, A; Acosta, T J; Onuma, M; Aida, Y

    2015-12-01

    Holstein cattle dominate the global milk production industry because of their outstanding milk production, however, this breed is susceptible to tropical endemic pathogens and suffers from heat stress and thus fewer Holstein populations are raised in tropical areas. The bovine major histocompatibility complex (BoLA)-DRB3 class II gene is used as a marker for disease and immunological traits, and its polymorphism has been studied extensively in Holstein cattle from temperate and cold regions. We studied the genetic diversity of the BoLA-DRB3 gene in South American Holstein populations to determine whether tropical populations have diverged from those bred in temperate and cold regions by selection and/or crossbreeding with local native breeds. We specifically studied Exon 2 of this gene from 855 South American Holstein individuals by a polymerase chain reaction (PCR) sequence-based typing method. We found a high degree of gene diversity at the allelic (Na > 20 and He > 0.87) and molecular (π > 0.080) levels, but a low degree of population structure (FST = 0.009215). A principal components analysis and tree showed that the Bolivian subtropical population had the largest genetic divergence compared with Holsteins bred in temperate or cold regions, and that this population was closely related to Bolivian Creole cattle. Our results suggest that Holstein genetic divergence can be explained by selection and/or gene introgression from local germplasms. This is the first examination of BoLA-DRB3 in Holsteins adapted to tropical environments, and contributes to an ongoing effort to catalog bovine MHC allele frequencies by breed and location.

  1. Mamu-A*01/Kb transgenic and MHC Class I knockout mice as a tool for HIV vaccine development

    International Nuclear Information System (INIS)

    We have developed a murine model expressing the rhesus macaque (RM) Mamu-A*01 MHC allele to characterize immune responses and vaccines based on antigens of importance to human disease processes. Towards that goal, transgenic (Tg) mice expressing chimeric RM (α1 and α2 Mamu-A*01 domains) and murine (α3, transmembrane, and cytoplasmic H-2Kb domains) MHC Class I molecules were derived by transgenesis of the H-2KbDb double MHC Class I knockout strain. After immunization of Mamu-A*01/Kb Tg mice with rVV-SIVGag-Pol, the mice generated CD8+ T-cell IFN-γ responses to several known Mamu-A*01 restricted epitopes from the SIV Gag and Pol antigen sequence. Fusion peptides of highly recognized CTL epitopes from SIV Pol and Gag and a strong T-help epitope were shown to be immunogenic and capable of limiting an rVV-SIVGag-Pol challenge. Mamu-A*01/Kb Tg mice provide a model system to study the Mamu-A*01 restricted T-cell response for various infectious diseases which are applicable to a study in RM.

  2. Differential recognition of MHC class I molecules of xeno-/allo-endothelial cells by human NK cells

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Using human umbilical vein endothelial cells (HUVEC) and porcine aortic endothelial cells (PAEC) as target cells, human peripheral blood NK cells (PBNK) and NK92 cells as effector cells, the differential cytotoxicities of NK cells to allo- and xeno-endothelial cells were studied. The influence of MHC class I molecules on the cytotoxicity of human NK cells was assayed using acid treatment, and blockades of MHC class I antigens, CD94 and KIR (NKB1). The results indicated that the killing of PAEC by the two kinds of NK cells is higher than that of HUVEC. After acid- treatment, the cytotoxicity of the two kinds of NK cells to PAEC and HUVEC is significantly enhanced, but the magnitude of the enhancement is different. The enhancement of NK killing to acid treated HUVEC is much greater than that to PAEC. Blockade of CD94 mAb did not alter the NK cytotoxicity, while blockade of NKB1 mAb enhanced the cytotoxicity of PBNK to HUVEC and PAEC by 95% and 29% respectively. The results above suggested that the differential recognition of MHC I molecules of xeno-endothelial cells by human NK cells could be the major reason for higher NK cytotoxicity to PAEC. KIR might be the primary molecule that transduced inhibitory signals when endothelial cells were injured by NK cells.

  3. Diversified Anchoring Features the Peptide Presentation of DLA-88*50801: First Structural Insight into Domestic Dog MHC Class I.

    Science.gov (United States)

    Xiao, Jin; Xiang, Wangzhen; Chai, Yan; Haywood, Joel; Qi, Jianxun; Ba, Limin; Qi, Peng; Wang, Ming; Liu, Jun; Gao, George F

    2016-09-15

    Canines represent a crucial animal model for studying human diseases and organ transplantation, as well as the evolution of domestic animals. MHCs, with a central role in cellular immunity, are commonly used in the study of dog population genetics and genome evolution. However, the molecular basis for the peptide presentation of dog MHC remains largely unknown. In this study, peptide presentation by canine MHC class I DLA-88*50801 was structurally determined, revealing diversified anchoring modes of the binding peptides. Flexible and large pockets composed of both hydrophobic and hydrophilic residues can accommodate pathogen-derived peptides with diverse anchor residues, as confirmed by thermostability measurements. Furthermore, DLA-88*50801 contains an unusual α2 helix with a large coil in the TCR contact region. These results further our understanding of canine T cell immunity through peptide presentation of MHC class I and shed light on the molecular basis for vaccine development for canine infectious diseases, for example, canine distemper virus. PMID:27511732

  4. Genetic variation and balancing selection at MHC class II exon 2 in cultured stocks and wild populations of orange-spotted grouper (Epinephelus coioides).

    Science.gov (United States)

    Meng, Z N; Yang, S; Fan, B; Wang, L; Lin, H R

    2012-11-12

    Major histocompatibility complex (MHC) molecules play vital roles in triggering adaptive immune responses and are considered the most variable molecules in vertebrates. Recently, many studies have focused on the polymorphism and evolution mode of MHC in both model and non-model organisms. Here, we analyzed the MHC class II exon 2-encoding β chain in comparison with the mitochondrial Cytb gene and our previously published microsatellite data set in three cultured stocks and four wild populations of the orange-spotted grouper (Epinephelus coioides) in order to investigate its genetic variation and mechanism of evolution. We detected one to four alleles in one individual, suggesting that at least two loci exist in the orange-spotted grouper, as well as a particularly high level of allelic diversity at the MHC loci. Furthermore, the cultured stocks exhibited reduced allelic diversity compared to the wild counterparts. We found evidence of balancing selection at MHC class II exon 2, and codon sites under positive selection were largely correspondent to the protein-binding region. In addition, MHC class II exon 2 revealed significant differences between population differentiation patterns from the neutral mitochondrial Cytb and microsatellites, which may indicate local adaptation at MHC loci in orange-spotted grouper originating from the South China Sea and Southeast Asia.

  5. Porcine major histocompatibility complex (MHC) class I molecules and analysis of their peptide-binding specificities

    DEFF Research Database (Denmark)

    Pedersen, Lasse Eggers; Harndahl, Mikkel; Rasmussen, Michael;

    2011-01-01

    CTL staining and manipulation. This has enabled a complete mapping of all HLA-I specificities (“the Human MHC Project”). Here, we demonstrate that these approaches can be applied to other species. We systematically transferred domains of the frequently expressed swine MHC-I molecule, SLA-1*0401, onto...... a HLA-I molecule (HLA-A*11:01), thereby generating recombinant human/swine chimeric MHC-I molecules as well as the intact SLA-1*0401 molecule. Biochemical peptide-binding assays and positional scanning combinatorial peptide libraries were used to analyze the peptide-binding motifs of these molecules....... A pan-specific predictor of peptide–MHC-I binding, NetMHCpan, which was originally developed to cover the binding specificities of all known HLA-I molecules, was successfully used to predict the specificities of the SLA-1*0401 molecule as well as the porcine/human chimeric MHC-I molecules. These data...

  6. Epigenetic regulations in the IFNγ signalling pathway: IFNγ-mediated MHC class I upregulation on tumour cells is associated with DNA demethylation of antigen-presenting machinery genes.

    Science.gov (United States)

    Vlková, Veronika; Štěpánek, Ivan; Hrušková, Veronika; Šenigl, Filip; Mayerová, Veronika; Šrámek, Martin; Šímová, Jana; Bieblová, Jana; Indrová, Marie; Hejhal, Tomáš; Dérian, Nicolas; Klatzmann, David; Six, Adrien; Reiniš, Milan

    2014-08-30

    Downregulation of MHC class I expression on tumour cells, a common mechanism by which tumour cells can escape from specific immune responses, can be associated with coordinated silencing of antigen-presenting machinery genes. The expression of these genes can be restored by IFNγ. In this study we documented association of DNA demethylation of selected antigen-presenting machinery genes located in the MHC genomic locus (TAP-1, TAP-2, LMP-2, LMP-7) upon IFNγ treatment with MHC class I upregulation on tumour cells in several MHC class I-deficient murine tumour cell lines (TC-1/A9, TRAMP-C2, MK16 and MC15). Our data also documented higher methylation levels in these genes in TC-1/A9 cells, as compared to their parental MHC class I-positive TC-1 cells. IFNγ-mediated DNA demethylation was relatively fast in comparison with demethylation induced by DNA methyltransferase inhibitor 5-azacytidine, and associated with increased histone H3 acetylation in the promoter regions of APM genes. Comparative transcriptome analysis in distinct MHC class I-deficient cell lines upon their treatment with either IFNγ or epigenetic agents revealed that a set of genes, significantly enriched for the antigen presentation pathway, was regulated in the same manner. Our data demonstrate that IFNγ acts as an epigenetic modifier when upregulating the expression of antigen-presenting machinery genes.

  7. MHC class I BFIV gene polymorphisms in four Chinese native chicken breeds.

    Science.gov (United States)

    Dai, Yin; Liu, Xue-Lan; Tang, Qing-Feng; Hu, Xiao-Miao; Shen, Xue-Huai; Zhang, Dan-Jun

    2016-09-01

    The major histocompatibility complex (MHC) includes the most polymorphic genes in vertebrates, and balancing selection has been proposed as a main evolutionary force. Here we present one of the first data sets examining the genetic characteristics of chicken MHC I BFIV molecules in four Chinese native breeds, sourced from different regions in China. In all, 89 BFIV alleles were isolated from 102 individuals sampled, and 13 repeated alleles were observed. No significant correlation was found between genetic differentiation and geographical distance in the phylogenetic tree. BFIV genes exhibited a high level of nucleotide polymorphisms, and most of the polymorphic sites were located in the peptide-binding region (PBR) encoded in exons 2 and 3. A comparison of the three-dimensional structures of PBRs in chicken BFIV and human HLA-A molecules revealed evident structural and functional similarities. The results suggested that MHC I molecules had similar structural features in different species. PMID:27168230

  8. Sculpting MHC class II-restricted self and non-self peptidome by the class I Ag-processing machinery and its impact on Th-cell responses.

    Science.gov (United States)

    Spencer, Charles T; Dragovic, Srdjan M; Conant, Stephanie B; Gray, Jennifer J; Zheng, Mu; Samir, Parimal; Niu, Xinnan; Moutaftsi, Magdalini; Van Kaer, Luc; Sette, Alessandro; Link, Andrew J; Joyce, Sebastian

    2013-05-01

    It is generally assumed that the MHC class I antigen (Ag)-processing (CAP) machinery - which supplies peptides for presentation by class I molecules - plays no role in class II-restricted presentation of cytoplasmic Ags. In striking contrast to this assumption, we previously reported that proteasome inhibition, TAP deficiency or ERAAP deficiency led to dramatically altered T helper (Th)-cell responses to allograft (HY) and microbial (Listeria monocytogenes) Ags. Herein, we tested whether altered Ag processing and presentation, altered CD4(+) T-cell repertoire, or both underlay the above finding. We found that TAP deficiency and ERAAP deficiency dramatically altered the quality of class II-associated self peptides suggesting that the CAP machinery impacts class II-restricted Ag processing and presentation. Consistent with altered self peptidomes, the CD4(+) T-cell receptor repertoire of mice deficient in the CAP machinery substantially differed from that of WT animals resulting in altered CD4(+) T-cell Ag recognition patterns. These data suggest that TAP and ERAAP sculpt the class II-restricted peptidome, impacting the CD4(+) T-cell repertoire, and ultimately altering Th-cell responses. Together with our previous findings, these data suggest multiple CAP machinery components sequester or degrade MHC class II-restricted epitopes that would otherwise be capable of eliciting functional Th-cell responses.

  9. Characterization of antigen processing and presentation by peptide-linked MHC class I molecules

    OpenAIRE

    Tiwari, Neeraj

    2005-01-01

    MHC-Klasse-I-Moleküle präsentieren gewöhnlich Peptide, die aus zytosolischen Antigenproteinen durch proteasomalen Verdau generiert und anschließend vom TAP-Peptidtransporter ins endoplasmatische Retikulum transportiert werden. Es können jedoch auch endozytierte Antigene für die MHC-Klasse-I-vermittelten Antigenpräsentation prozessiert werden, wobei dieser alternative Weg entweder in einer Proteasom/TAP-abhängigen oder unabhängigen Weise abläuft. Während diese so genannte „Kreuzpräsentation“ f...

  10. Characterization of the expressed CIITA allele in the class II MHC transcriptional mutant RJ2.2.5

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.A.; He, X.F.; Westerheide, S.D. [Emory Univ. School of Medicine, Atlanta, GA (United States)] [and others

    1996-06-01

    Class II major histocompatibility complex (MHC) genes are regulated in a coordinate manner. A set of conserved upstream elements termed the W/Z/S, X1, X2, and Y boxes are found 5{prime} to class II genes, the R gene, and the HLA-DM genes. These conserved elements are required for tissue-specific and IFN{gamma}-mediated regulation of these genes. The DNA-binding proteins RFX, X2BP, and NFY have been found to specifically interact with the X1, X2, and Y box elements, respectively, as well as with each other. A role for an additional factor was recently demonstrated by the cloning of a gene that could complement the MHC class H gene-specific transcriptional deficiency in the mutant cell line RJ2.2.5 as well as cell lines isolated from patients exhibiting the bare lymphocyte syndrome. This gene was termed the class II transactivator or CIITA. While both genetic and biochemical studies have indicated interactions between the DNA-binding proteins described above, direct interactions with CIITA have not been described. 23 refs., 3 figs.

  11. Heligmosomoides polygyrus infection is associated with lower MHC class II gene expression in Apodemus flavicollis: indication for immune suppression?

    Science.gov (United States)

    Axtner, Jan; Sommer, Simone

    2011-12-01

    Due to their key role in recognizing foreign antigens and triggering the subsequent immune response the genes of the major histocompatibility complex (MHC) provide a potential target for parasites to attack in order to evade detection and expulsion from the host. A diminished MHC gene expression results in less activated T cells and might serve as a gateway for pathogens and parasites. Some parasites are suspected to be immune suppressors and promote co-infections of other parasites even in other parts of the body. In our study we found indications that the gut dwelling nematode Heligmosomoides polygyrus might exert a systemic immunosuppressive effect in yellow-necked mice (Apodemus flavicollis). The amount of hepatic MHC class II DRB gene RNA transcripts in infected mice was negatively associated with infection intensity with H. polygyrus. The hepatic expression of immunosuppressive cytokines, such as transforming growth factor β and interleukin 10 was not associated with H. polygyrus infection. We did not find direct positive associations of H. polygyrus with other helminth species. But the prevalence and infection intensity of the nematodes Syphacia stroma and Trichuris muris were higher in multiple infected individuals. Furthermore, our data indicated antagonistic effects in the helminth community of A. flavicollis as cestode infection correlated negatively with H. polygyrus and helminth species richness. Our study shows that expression analyses of immune relevant genes can also be performed in wildlife, opening new aspects and possibilities for future ecological and evolutionary research. PMID:21983561

  12. Genetic variation of the major histocompatibility complex (MHC class II B gene in the threatened Hume's pheasant, Syrmaticus humiae.

    Directory of Open Access Journals (Sweden)

    Weicai Chen

    Full Text Available Major histocompatibility complex (MHC genes are the most polymorphic genes in vertebrates and encode molecules that play a crucial role in pathogen resistance. As a result of their diversity, they have received much attention in the fields of evolutionary and conservation biology. Here, we described the genetic variation of MHC class II B (MHCIIB exon 2 in a wild population of Hume's pheasant (Syrmaticus humiae, which has suffered a dramatic decline in population over the last three decades across its ranges in the face of heavy exploitation and habitat loss. Twenty-four distinct alleles were found in 73 S. humiae specimens. We found seven shared alleles among four geographical groups as well as six rare MHCIIB alleles. Most individuals displayed between one to five alleles, suggesting that there are at least three MHCIIB loci of the Hume's pheasant. The dN ⁄ dS ratio at putative antigen-binding sites (ABS was significantly greater than one, indicating balancing selection is acting on MHCIIB exon 2. Additionally, recombination and gene conversion contributed to generating MHCIIB diversity in the Hume's pheasant. One to three recombination events and seventy-five significant gene conversion events were observed within the Hume's pheasant MHCIIB loci. The phylogenetic tree and network analysis revealed that the Hume's pheasant alleles do not cluster together, but are scattered through the tree or network indicating a trans-species evolutionary mode. These findings revealed the evolution of the Hume's pheasant MHC after suffering extreme habitat fragmentation.

  13. Vaccine-induced antibodies linked to bovine neonatal pancytopenia (BNP) recognize cattle major histocompatibility complex class I (MHC I).

    Science.gov (United States)

    Deutskens, Fabian; Lamp, Benjamin; Riedel, Christiane M; Wentz, Eveline; Lochnit, Günter; Doll, Klaus; Thiel, Heinz-Jürgen; Rümenapf, Till

    2011-01-01

    A mysterious disease affecting calves, named bovine neonatal pancytopenia (BNP), emerged in 2007 in several European countries. Epidemiological studies revealed a connection between BNP and vaccination with an inactivated vaccine against bovine virus diarrhea (BVD). Alloantibodies reacting with blood leukocytes of calves were detected in serum and colostrum of dams, which have given birth to calves affected by BNP. To understand the linkage between vaccination and the development of alloantibodies, we determined the antigens reacting with these alloantibodies. Immunoprecipitation of surface proteins from bovine leukocytes and kidney cells using sera from dams with a confirmed case of BNP in their gestation history reacted with two dominant protein species of 44 and 12 kDa. These proteins were not detected by sera from dams, free of BVDV and not vaccinated against BVD, and from sera of animals vaccinated with a different inactivated BVD vaccine. The 44 kDa protein was identified by mass spectrometry analysis as MHC I, the other as β-2-microglobulin. The presence of major histocompatibility complex class I (MHC I) in the vaccine was confirmed by Western blot using a MHC I specific monoclonal antibody. A model of BNP pathogenesis is proposed. PMID:21878124

  14. Vaccine-induced antibodies linked to bovine neonatal pancytopenia (BNP recognize cattle major histocompatibility complex class I (MHC I

    Directory of Open Access Journals (Sweden)

    Deutskens Fabian

    2011-08-01

    Full Text Available Abstract A mysterious disease affecting calves, named bovine neonatal pancytopenia (BNP, emerged in 2007 in several European countries. Epidemiological studies revealed a connection between BNP and vaccination with an inactivated vaccine against bovine virus diarrhea (BVD. Alloantibodies reacting with blood leukocytes of calves were detected in serum and colostrum of dams, which have given birth to calves affected by BNP. To understand the linkage between vaccination and the development of alloantibodies, we determined the antigens reacting with these alloantibodies. Immunoprecipitation of surface proteins from bovine leukocytes and kidney cells using sera from dams with a confirmed case of BNP in their gestation history reacted with two dominant protein species of 44 and 12 kDa. These proteins were not detected by sera from dams, free of BVDV and not vaccinated against BVD, and from sera of animals vaccinated with a different inactivated BVD vaccine. The 44 kDa protein was identified by mass spectrometry analysis as MHC I, the other as β-2-microglobulin. The presence of major histocompatibility complex class I (MHC I in the vaccine was confirmed by Western blot using a MHC I specific monoclonal antibody. A model of BNP pathogenesis is proposed.

  15. NMR spectroscopy reveals unexpected structural variation at the protein-protein interface in MHC class I molecules

    Energy Technology Data Exchange (ETDEWEB)

    Beerbaum, Monika; Ballaschk, Martin; Erdmann, Natalja [Leibniz-Institut fuer Molekulare Pharmakologie (FMP) (Germany); Schnick, Christina [Freie Universitaet Berlin, Institut fuer Immungenetik, Charite-Universitaetsmedizin Berlin (Germany); Diehl, Anne [Leibniz-Institut fuer Molekulare Pharmakologie (FMP) (Germany); Uchanska-Ziegler, Barbara; Ziegler, Andreas [Freie Universitaet Berlin, Institut fuer Immungenetik, Charite-Universitaetsmedizin Berlin (Germany); Schmieder, Peter, E-mail: schmieder@fmp-berlin.de [Leibniz-Institut fuer Molekulare Pharmakologie (FMP) (Germany)

    2013-10-15

    {beta}{sub 2}-Microglobulin ({beta}{sub 2}m) is a small, monomorphic protein non-covalently bound to the heavy chain (HC) in polymorphic major histocompatibility complex (MHC) class I molecules. Given the high evolutionary conservation of structural features of {beta}{sub 2}m in various MHC molecules as shown by X-ray crystallography, {beta}{sub 2}m is often considered as a mere scaffolding protein. Using nuclear magnetic resonance (NMR) spectroscopy, we investigate here whether {beta}{sub 2}m residues at the interface to the HC exhibit changes depending on HC polymorphisms and the peptides bound to the complex in solution. First we show that human {beta}{sub 2}m can effectively be produced in deuterated form using high-cell-density-fermentation and we employ the NMR resonance assignments obtained for triple-labeled {beta}{sub 2}m bound to the HLA-B*27:09 HC to examine the {beta}{sub 2}m-HC interface. We then proceed to compare the resonances of {beta}{sub 2}m in two minimally distinct subtypes, HLA-B*27:09 and HLA-B*27:05, that are differentially associated with the spondyloarthropathy Ankylosing Spondylitis. Each of these subtypes is complexed with four distinct peptides for which structural information is already available. We find that only the resonances at the {beta}{sub 2}m-HC interface show a variation of their chemical shifts between the different complexes. This indicates the existence of an unexpected plasticity that enables {beta}{sub 2}m to accommodate changes that depend on HC polymorphism as well as on the bound peptide through subtle structural variations of the protein-protein interface.

  16. MHC class II-assortative mate choice in European badgers (Meles meles)

    NARCIS (Netherlands)

    Sin, Yung Wa; Annavi, Geetha; Newman, Chris; Buesching, Christina D.; Burke, Terry; Macdonald, David W.; Dugdale, Hannah

    2015-01-01

    The major histocompatibility complex (MHC) plays a crucial role in the immune system, and in some species, it is a target by which individuals choose mates to optimize the fitness of their offspring, potentially mediated by olfactory cues. Under the genetic compatibility hypothesis, individuals are

  17. MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

    Directory of Open Access Journals (Sweden)

    Yasukochi Yoshiki

    2012-11-01

    Full Text Available Abstract Background The major histocompatibility complex (MHC genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus. Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus from 12 local populations. Results Among 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes and one putative pseudogene. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected. Conclusions The low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other

  18. Regulatory functions of self-restricted MHC class II allopeptide-specific Th2 clones in vivo

    OpenAIRE

    Waaga, Ana Maria; Gasser, Martin; Kist-van Holthe, Joana E; Najafian, Nader; Müller, Angelika; Vella, John P.; Womer, Karl L.; Chandraker, Anil; Khoury, Samia J.; Sayegh, Mohamed H.

    2001-01-01

    We studied T-cell clones generated from grafts of rejecting and tolerant animals and investigated the regulatory function of Th2 clones in vitro and in vivo. To prevent allograft rejection, we treated LEW strain recipient rats of WF strain kidney grafts with CTLA4Ig to block CD28-B7 costimulation. We then isolated epitope-specific T-cell clones from the engrafted tissue, using a donor-derived immunodominant class II MHC allopeptide presented by recipient antigen-presenting cells. Acutely reje...

  19. Pan-specific prediction of peptide-MHC Class I complex stability, a correlate of T cell immunogenicity

    DEFF Research Database (Denmark)

    Rasmussen, Michael; Fenoy, Emilio; Harndahl, Mikkel;

    2016-01-01

    of a large panel of human MHC-I allotypes and generated a body of data sufficient to develop a neural network-based pan-specific predictor of peptide-MHC-I complex stability. Integrating the neural network predictors of peptide-MHC-I complex stability with state-of-the-art predictors of peptide-MHC-I binding...

  20. NK cells infiltrating a MHC class I-deficient lung adenocarcinoma display impaired cytotoxic activity toward autologous tumor cells associated with altered NK cell-triggering receptors.

    Science.gov (United States)

    Le Maux Chansac, Béatrice; Moretta, Alessandro; Vergnon, Isabelle; Opolon, Paule; Lécluse, Yann; Grunenwald, Dominique; Kubin, Marek; Soria, Jean-Charles; Chouaib, Salem; Mami-Chouaib, Fathia

    2005-11-01

    NK cells are able to discriminate between normal cells and cells that have lost MHC class I (MHC-I) molecule expression as a result of tumor transformation. This function is the outcome of the capacity of inhibitory NK receptors to block cytotoxicity upon interaction with their MHC-I ligands expressed on target cells. To investigate the role of human NK cells and their various receptors in the control of MHC-I-deficient tumors, we have isolated several NK cell clones from lymphocytes infiltrating an adenocarcinoma lacking beta2-microglobulin expression. Unexpectedly, although these clones expressed NKG2D and mediated a strong cytolytic activity toward K562, Daudi and allogeneic MHC-class I+ carcinoma cells, they were unable to lyse the autologous MHC-I- tumor cell line. This defect was associated with alterations in the expression of natural cytotoxicity receptor (NCR) by NK cells and the NKG2D ligands, MHC-I-related chain A, MHC-I-related chain B, and UL16 binding protein 1, and the ICAM-1 by tumor cells. In contrast, the carcinoma cell line was partially sensitive to allogeneic healthy donor NK cells expressing high levels of NCR. Indeed, this lysis was inhibited by anti-NCR and anti-NKG2D mAbs, suggesting that both receptors are required for the induced killing. The present study indicates that the MHC-I-deficient lung adenocarcinoma had developed mechanisms of escape from the innate immune response based on down-regulation of NCR and ligands required for target cell recognition.

  1. Predicting promiscuous antigenic T cell epitopes of Mycobacterium tuberculosis mymA operon proteins binding to MHC Class I and Class II molecules.

    Science.gov (United States)

    Saraav, Iti; Pandey, Kirti; Sharma, Monika; Singh, Swati; Dutta, Prasun; Bhardwaj, Anshu; Sharma, Sadhna

    2016-10-01

    Limited efficacy of Bacillus Calmette-Guérin vaccine has raised the need to explore other immunogenic candidates to develop an effective vaccine against Mycobacterium tuberculosis (Mtb). Both CD4+ and CD8+ T cells play a critical role in host immunity to Mtb. Infection of macrophages with Mtb results in upregulation of mymA operon genes thereby suggesting their importance as immune targets. In the present study, after exclusion of self-peptides mymA operon proteins of Mtb were analyzed in silico for the presence of Human Leukocyte Antigen (HLA) Class I and Class II binding peptides using Bioinformatics and molecular analysis section, NetMHC 3.4, ProPred and Immune epitope database software. Out of 56 promiscuous epitopes obtained, 41 epitopes were predicted to be antigenic for MHC Class I. In MHC Class II, out of 336 promiscuous epitopes obtained, 142 epitopes were predicted to be antigenic. The comparative bioinformatics analysis of mymA operon proteins found Rv3083 to be the best vaccine candidate. Molecular docking was performed with the most antigenic peptides of Rv3083 (LASGAASVV with alleles HLA-B51:01, HAATSGTLI with HLA-A02, IVTATGLNI and EKIHYGLKVNTA with HLA-DRB1_01:01) to study the structural basis for recognition of peptides by various HLA molecules. The software binding prediction was validated by the obtained molecular docking score of peptide-HLA complex. These peptides can be further investigated for their immunological relevance in patients of tuberculosis using major histocompatibility complex tetramer approach. PMID:27389362

  2. Differential recognition of MHC class I molecules of xeno-/allo-endothelial cells by human NK cells

    Institute of Scientific and Technical Information of China (English)

    冯志民; 张晓峰; 王宏芳; 丰美福

    2000-01-01

    Using human umbilical vein endothelial cells (HUVEC) and porcine aortic endothelial cells (PAEC) as target cells, human peripheral blood NK cells (PBNK) and NK92 cells as effector cells, the differential cytotoxicities of NK cells to allo- and xeno-endothelial cells were studied. The influence of MHC class I molecules on the cytotoxicity of human NK cells was assayed using acid treatment, and blockades of MHC class I antigens, CD94 and KIR (NKB1). The results indicated that the killing of PAEC by the two kinds of NK cells is higher than that of HUVEC. After acid-treatment, the cytotoxicity of the two kinds of NK cells to PAEC and HUVEC is significantly enhanced, but the magnitude of the enhancement is different. The enhancement of NK killing to acid treated HUVEC is much greater than that to PAEC. Blockade of CD94 mAb did not alter the NK cytotoxicity, while blockade of NKB1 mAb enhanced the cytotoxicity of PBNK to HUVEC and PAEC by 95% and 29% respectively. The results above suggested that the different

  3. The identification of additional zebrafish DICP genes reveals haplotype variation and linkage to MHC class I genes.

    Science.gov (United States)

    Rodriguez-Nunez, Ivan; Wcisel, Dustin J; Litman, Ronda T; Litman, Gary W; Yoder, Jeffrey A

    2016-04-01

    Bony fish encode multiple multi-gene families of membrane receptors that are comprised of immunoglobulin (Ig) domains and are predicted to function in innate immunity. One of these families, the diverse immunoglobulin (Ig) domain-containing protein (DICP) genes, maps to three chromosomal loci in zebrafish. Most DICPs possess one or two Ig ectodomains and include membrane-bound and secreted forms. Membrane-bound DICPs include putative inhibitory and activating receptors. Recombinant DICP Ig domains bind lipids with varying specificity, a characteristic shared with mammalian CD300 and TREM family members. Numerous DICP transcripts amplified from different lines of zebrafish did not match the zebrafish reference genome sequence suggesting polymorphic and haplotypic variation. The expression of DICPs in three different lines of zebrafish has been characterized employing PCR-based strategies. Certain DICPs exhibit restricted expression in adult tissues whereas others are expressed ubiquitously. Transcripts of a subset of DICPs can be detected during embryonic development suggesting roles in embryonic immunity or other developmental processes. Transcripts representing 11 previously uncharacterized DICP sequences were identified. The assignment of two of these sequences to an unplaced genomic scaffold resulted in the identification of an alternative DICP haplotype that is linked to a MHC class I Z lineage haplotype on zebrafish chromosome 3. The linkage of DICP and MHC class I genes also is observable in the genomes of the related grass carp (Ctenopharyngodon idellus) and common carp (Cyprinus carpio) suggesting that this is a shared character with the last common Cyprinidae ancestor. PMID:26801775

  4. Induction of tolerance against the arthritogenic antigen with type-II collagen peptide-linked soluble MHC class II molecules

    Science.gov (United States)

    Park, Yoon-Kyung; Jung, Sundo; Park, Se-Ho

    2016-01-01

    In murine collagen-induced arthritis (CIA), self-reactive T cells can recognize peptide antigens derived from type-II collagen (CII). Activation of T cells is an important mediator of autoimmune diseases. Thus, T cells have become a focal point of study to treat autoimmune diseases. In this study, we evaluated the efficacy of recombinant MHC class II molecules in the regulation of antigen-specific T cells by using a self peptide derived from CII (CII260-274; IAGFKGEQGPKGEPG) linked to mouseI-Aq in a murine CIA model. We found that recombinant I-Aq/CII260-274 molecules could be recognized by CII-specific T cells and inhibit the same T cells in vitro. Furthermore, the development of CIA in mice was successfully prevented by in vivo injection of recombinant I-Aq/CII260-274 molecules. Thus, treatment with recombinant soluble MHC class II molecules in complex with an immunodominant self-peptide might offer a potential therapeutic for chronic inflammation in autoimmune disease such as rheumatoid arthritis. [BMB Reports 2016; 49(6): 331-336 PMID:26779996

  5. Protein tyrosine kinases p53/56lyn and p72syk in MHC class I-mediated signal transduction in B lymphoma cells

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Bregenholt, S; Skov, S;

    1998-01-01

    Crosslinking of major histocompatibility complex class I (MHC-I) molecules on the surface of human B lymphoma cells was shown to induce protein tyrosine phosphorylation and mobilization of intracellular free calcium. Immunoprecipitations indicated that the protein tyrosine kinases p53/56lyn and p72......syk are among the tyrosine-phosphorylated proteins. The kinetics of phosphorylation of these kinases after MHC-I crosslinking differ from the kinetics observed after crosslinking of the B cell antigen receptor (BCR). Additional experiments were performed with chicken lyn- and syk-negative DT40 B cells...... and the results indicate that these two kinases have different substrate specificity and regulate intracellular free calcium differently in response to MHC-I crosslinking. In addition MHC-I crosslinking of a sIgM-negative DT40 chicken B cell variant results in less activity of tyrosine kinases and less...

  6. Intracellular transport of MHC class II and associated invariant chain in antigen presenting cells from AP-3-deficient mocha mice.

    Science.gov (United States)

    Sevilla, L M; Richter, S S; Miller, J

    2001-06-15

    MHC class II-restricted antigen presentation requires trafficking of newly synthesized class II-invariant chain complexes from the trans-Golgi network to endosomal, peptide-loading compartments. This transport is mediated by dileucine-like motifs within the cytosolic tail of the invariant chain. Although these signals have been well characterized, the cytosolic proteins that interact with these dileucine signals and mediate Golgi sorting and endosomal transport have not been identified. Recently, an adaptor complex, AP-3, has been identified that interacts with dileucine motifs and mediates endosomal/lysosomal transport in yeast, Drosophila, and mammals. In this report, we have assessed class II-invariant chain trafficking in a strain of mice (mocha) which lacks expression of AP-3. Our studies demonstrate that the lack of AP-3 does not affect the kinetics of invariant chain degradation, the route of class II-invariant chain transport, or the rate and extent of class II-peptide binding as assessed by the generation of SDS-stable dimers. The possible role of other known or unknown adaptor complexes in class II-invariant chain transport is discussed. PMID:11520080

  7. Differences in non-MHC restricted cytotoxic activities of human peripheral blood lymphocytes after transfusion with allogeneic leukocytes or platelets possessing class I and/or class II MHC molecules.

    Science.gov (United States)

    Pócsik, E; Mihalik, R; Réti, M; Gyódi, E; Pálóczi, K; Mayer, K; Kassai, M; Herold, M; Huber, C; Petrányi, G G

    1990-12-01

    MHC-unrestricted cytotoxic activity of peripheral blood lymphocytes (PBL) from 4-6 healthy donors was investigated before and after transfusion with allogeneic leukocytes or platelets. Natural killer and lectin-dependent cellular cytotoxicity (LDCC) of PBL was tested against K562 and Raji target cells in a 4-h and 16-h 51Cr-release assay, respectively. After allotransfusion with leukocytes, we found increased cytotoxic activity of each donor's PBL against all the three targets on day 3 or 7. The highest non-specific cytotoxic activity was detected against the relatively NK resistant Raji target cells. The increase of cytotoxic activity was lowest against the LDCC target (PHA-treated Raji) cells. On the contrary, no changes in cytotoxic activity against any targets were observed after allotransfusion with platelets (possessing class I HLA antigens but no HLA class II molecules). Our results suggest that HLA class II molecules, presumably by inducing immune responses, are essential for activation/generation of non-specific killing of tumor targets after leukocyte transfusion. Thrombocytes, known to be less immunogenic than leukocytes, are not effective in in vivo enhancing of non-specific cytotoxicity. Cellular activation of PBL following leukocyte allotransfusion was confirmed by detection of elevated serum neopterin and beta-2-microglobulin levels on day 3. This was not the case after platelet allotransfusion. In addition, the expression of ICAM-1 antigen (as a molecule involved directly in MHC-unrestricted cytotoxicity) was also found to be increased in two donors' PBL on day 3 after leukocyte transfusion in contrast to transfusion with platelets.

  8. The ER aminopeptidase, ERAP1, trims precursors to lengths of MHC class I peptides by a “molecular ruler” mechanism

    OpenAIRE

    Chang, Shih-Chung; Momburg, Frank; Bhutani, Nidhi; Goldberg, Alfred L.

    2005-01-01

    Endoplasmic reticulum aminopeptidase 1 (ERAP1) is an IFN-γ-induced aminopeptidase in the endoplasmic reticulum that trims longer precursors to the antigenic peptides presented on MHC class I molecules. We recently reported that purified ERAP1 trimmed N-extended precursors but spared peptides of 8-9 residues, the length required for binding to MHC class I molecules. Here, we show another remarkable property of ERAP1: that it strongly prefers substrates 9-16 residues long, the lengths of peptid...

  9. The major histocompatibility complex (Mhc class IIB region has greater genomic structural flexibility and diversity in the quail than the chicken

    Directory of Open Access Journals (Sweden)

    Kulski Jerzy K

    2006-12-01

    Full Text Available Abstract Background The quail and chicken major histocompatibility complex (Mhc genomic regions have a similar overall organization but differ markedly in that the quail has an expanded number of duplicated class I, class IIB, natural killer (NK-receptor-like, lectin-like and BG genes. Therefore, the elucidation of genetic factors that contribute to the greater Mhc diversity in the quail would help to establish it as a model experimental animal in the investigation of avian Mhc associated diseases. Aims and approaches The main aim here was to characterize the genetic and genomic features of the transcribed major quail MhcIIB (CojaIIB region that is located between the Tapasin and BRD2 genes, and to compare our findings to the available information for the chicken MhcIIB (BLB. We used four approaches in the study of the quail MhcIIB region, (1 haplotype analyses with polymorphic loci, (2 cloning and sequencing of the RT-PCR CojaIIB products from individuals with different haplotypes, (3 genomic sequencing of the CojaIIB region from the individuals with the different haplotypes, and (4 phylogenetic and duplication analysis to explain the variability of the region between the quail and the chicken. Results Our results show that the Tapasin-BRD2 segment of the quail Mhc is highly variable in length and in gene transcription intensity and content. Haplotypic sequences were found to vary in length between 4 to 11 kb. Tapasin-BRD2 segments contain one or two major transcribed CojaIIBs that were probably generated by segmental duplications involving c-type lectin-like genes and NK receptor-like genes, gene fusions between two CojaIIBs and transpositions between the major and minor CojaIIB segments. The relative evolutionary speed for generating the MhcIIBs genomic structures from the ancestral BLB2 was estimated to be two times faster in the quail than in the chicken after their separation from a common ancestor. Four types of genomic rearrangement

  10. An approach to mapping haplotype-specific recombination sites in human MHC class III

    Energy Technology Data Exchange (ETDEWEB)

    Levo, A.; Westman, P.; Partanen, J. [Finnish Red Cross Blood Transfusion Service, Helsinki (Finland)

    1996-12-31

    Studies of the major histocompatibility complex (MHC) in mouse indicate that the recombination sites are not randomly distributed and their occurrence is haplotype-dependent. No data concerning haplotype-specific recombination sites in human are available due to the low number of informative families. To investigate haplotype-specific recombination sites in human MHC, we describe an approach based on identification of recombinant haplotypes derived from one conserved haplotype at the population level. The recombination sites were mapped by comparing polymorphic markers between the recombinant and assumed original haplotypes. We tested this approach on the extended haplotype HLA A3; B47; Bf{sup *}F; C4A{sup *}1; C4B{sup *}Q0; DR7, which is most suitable for this analysis. First, it carries a number of rare markers, and second, the haplotype, albeit rare in the general population, is frequent in patients with 21-hydroxylase (21OH) defect. We observed recombinants derived from this haplotype in patients with 21OH defect. All these haplotypes had the centromeric part (from Bf to DR) identical to the original haplotype, but they differed in HLA A and B. We therefore assumed that they underwent recombinations in the segment that separates the Bf and HLA B genes. Polymorphic markers indicated that all break points mapped to two segments near the TNF locus. This approach makes possible the mapping of preferential recombination sites in different haplotypes. 20 refs., 1 fig., 1 tab.

  11. Heparan Sulfate Proteoglycans Promote Telomerase Internalization and MHC Class II Presentation on Dendritic Cells.

    Science.gov (United States)

    Galaine, Jeanne; Kellermann, Guillaume; Guillaume, Yves; Boidot, Romain; Picard, Emilie; Loyon, Romain; Queiroz, Lise; Boullerot, Laura; Beziaud, Laurent; Jary, Marine; Mansi, Laura; André, Claire; Lethier, Lydie; Ségal-Bendirdjian, Evelyne; Borg, Christophe; Godet, Yann; Adotévi, Olivier

    2016-09-01

    Telomerase is a prototype-shared tumor Ag and represents an attractive target for anticancer immunotherapy. We have previously described promiscuous and immunogenic HLA-DR-restricted peptides derived from human telomerase reverse transcriptase (hTERT) and referred as universal cancer peptide (UCP). In nonsmall cell lung cancer, the presence of spontaneous UCP-specific CD4 T cell responses increases the survival of chemotherapy-responding patients. However, the precise mechanisms of hTERT's uptake, processing, and presentation on MHC-II molecules to stimulate CD4 T cells are poorly understood. In this work, by using well-characterized UCP-specific CD4 T cell clones, we showed that hTERT processing and presentation on MHC-II involve both classical endolysosomal and nonclassical cytosolic pathways. Furthermore, to our knowledge, we demonstrated for the first time that hTERT's internalization by dendritic cells requires its interaction with surface heparan sulfate proteoglycans. Altogether, our findings provide a novel mechanism of tumor-specific CD4 T cell activation and will be useful for the development of novel cancer immunotherapies that harness CD4 T cells. PMID:27481844

  12. Peptide motifs of the single dominantly expressed class I molecule explain the striking MHC-determined response to Rous sarcoma virus in chickens

    DEFF Research Database (Denmark)

    Wallny, Hans-Joachim; Avila, David; Hunt, Lawrence G.;

    2006-01-01

    are consistent with the peptides binding to models of the class I molecule encoded by the abundant cDNA. Finally, having shown for three haplotypes that there is a single dominantly expressed class I molecule at the level of RNA, protein, and antigenic peptide, we show that the motifs can explain the striking......Compared with the MHC of typical mammals, the chicken MHC is smaller and simpler, with only two class I genes found in the B12 haplotype. We make five points to show that there is a single-dominantly expressed class I molecule that can have a strong effect on MHC function. First, we find only one cDNA...... for two MHC haplotypes (B14 and B15) and cDNAs corresponding to two genes for the other six (B2, B4, B6, B12, B19, and B21). Second, we find, for the B4, B12, and B15 haplotypes, that one cDNA is at least 10-fold more abundant than the other. Third, we use 2D gel electrophoresis of class I molecules from...

  13. p53 increases MHC class I expression by upregulating the endoplasmic reticulum aminopeptidase ERAP1

    OpenAIRE

    Wang, Bei; Niu, Dandan; Lai, Liyun; Ren, Ee Chee

    2013-01-01

    The p53 tumour suppressor has an important role in cancer cells. Here we show that p53 regulates expression of major histocompatibility complex I on the cell surface. We show that the tumour cell line HCT116, which lacks p53 exhibits significantly lower major histocompatibility complex I expression than its wild-type counterpart. Using a combination of chromatin immunoprecipitation sequencing and gene expression analysis, we demonstrate that p53 upregulates expression of endoplasmic reticulum...

  14. Alternative Splice Transcripts for MHC Class I-like MICA Encode Novel NKG2D Ligands with Agonist or Antagonist Functions.

    Science.gov (United States)

    Gavlovsky, Pierre-Jean; Tonnerre, Pierre; Gérard, Nathalie; Nedellec, Steven; Daman, Andrew W; McFarland, Benjamin J; Charreau, Béatrice

    2016-08-01

    MHC class I chain-related proteins A and B (MICA and MICB) and UL16-binding proteins are ligands of the activating NKG2D receptor involved in cancer and immune surveillance of infection. Structurally, MICA/B proteins contain an α3 domain, whereas UL16-binding proteins do not. We identified novel alternative splice transcripts for MICA encoding five novel MICA isoforms: MICA-A, -B1, -B2, -C, and -D. Alternative splicing associates with MICA*015 and *017 and results from a point deletion (G) in the 5' splice donor site of MICA intron 4 leading to exon 3 and exon 4 skipping and/or deletions. These changes delete the α3 domain in all isoforms, and the α2 domain in the majority of isoforms (A, B1, C, and D). Endothelial and hematopoietic cells contained endogenous alternative splice transcripts and isoforms. MICA-B1, -B2, and -D bound NKG2D by surface plasmon resonance and were expressed at the cell surface. Functionally, MICA-B2 contains two extracellular domains (α1 and α2) and is a novel potent agonist ligand for NKG2D. We found that MICA-D is a new truncated form of MICA with weak affinity for NKG2D despite lacking α2 and α3 domains. MICA-D may functionally impair NKG2D activation by competing with full-length MICA or MICA-B2 for NKG2D engagement. Our study established NKG2D binding for recombinant MICA-B1 but found no function for this isoform. New truncated MICA isoforms exhibit a range of functions that may drive unexpected immune mechanisms and provide new tools for immunotherapy.

  15. Cellular expression or binding of desLys58-beta2 microglobulin is not dependent on the presence of the tri-molecular MHC class I complex.

    Science.gov (United States)

    Wang, M; Corlin, D B; Heegaard, N H H; Claesson, M H; Nissen, M H

    2008-02-01

    The monoclonal antibody 332-01 is a newly developed antibody which specifically recognizes human desLys58-beta2 microglobulin (dbeta2m). In the present study, we characterized the binding of 332-01 to peripheral blood mononuclear cells (PBMC), a number of human leukaemic and monocytic cell lines, and beta2m gene-deleted murine lymphocytes. dbeta2m was found to be expressed on non-activated and activated monocytes. When cells were pre-exposed to dbeta2m, 332-01 also bound to non-activated T lymphocytes. dbeta2m was expressed on the monocytic cell lines U937 and TIB-202, and binding was significantly increased when cells were pre-incubated with dbeta2m and when TIB-202 cells were exposed to lipopolysaccharide. dbeta2m was also expressed on T leukaemic Jurkat cells as well as on low HLA-expressing erythroleukaemic K562 cells. beta2m gene-deleted murine splenocytes only bound 332-01 after pre-exposure to dbeta2m. Binding of 332-01 antibody could not be displaced by addition of high concentrations of native beta2m. In conclusion, our data indicate that dbeta2m - in contrast to native beta2m - binds to a hitherto unknown cell surface receptor independent of classical MHC class I molecules. As beta2m has previously been shown to display biological activities such as the induction of both growth promotion and apoptosis, C1 complement activity, shown to mediate cleavage of beta2m, could be involved in these processes.

  16. Variations in the cytoplasmic region account for the heterogeneity of the chicken MHC class I (B-F) molecules

    DEFF Research Database (Denmark)

    Møller, L B; Kaufman, J; Verland, S;

    1991-01-01

    Molecular variation among major histocompatibility complex (MHC) class I (B-F) proteins from B-homozygous chickens is apparently caused by C-terminal variation. Analysis of the total B-F protein pool revealed substantial heterogeneity with two or three molecular mass constituents, each being...... comprised by several isoelectric focusing variants. This heterogeneity could not be reduced by enzymatic deglycosylation. By contrast, proteolytic removal of a small (Mr 1000-4000) fragment from the alpha chain resulted in the generation of a Mr 36,000 fragment, common to all the molecular mass variants...... properties of fragments obtained by gradual proteolytic digestion, indicated that the small peptide responsible for the major B-F heterogeneity was situated in the intracellular, C-terminal part. Udgivelsesdato: 1991-null...

  17. How do CD4+ T cells detect and eliminate tumor cells that either lack or express MHC class II molecules?

    Directory of Open Access Journals (Sweden)

    Ole Audun Werner Haabeth

    2014-04-01

    Full Text Available CD4+ T cells contribute to tumor eradication, even in the absence of CD8+ T cells. Cytotoxic CD4+ T cells can directly kill MHC class II positive tumor cells. More surprisingly, CD4+ T cells can indirectly eliminate tumor cells that lack MHC class II expression. Here, we review the mechanisms of direct and indirect CD4+ T cell-mediated elimination of tumor cells. An emphasis is put on T cell receptor (TCR transgenic models, where anti-tumor responses of naïve CD4+ T cells of defined specificity can be tracked. Some generalizations can tentatively be made. For both MHCIIPOS and MHCIINEG tumors, presentation of tumor specific antigen by host antigen presenting cells (APCs appears to be required for CD4+ T cell priming. This has been extensively studied in a myeloma model (MOPC315, where host APCs in tumor-draining lymph nodes are primed with secreted tumor antigen. Upon antigen recognition, naïve CD4+ T cells differentiate into Th1 cells and migrate to the tumor. At the tumor site, the mechanisms for elimination of MHCIIPOS and MHCIINEG tumor cells differ. In a TCR transgenic B16 melanoma model, MHCIIPOS melanoma cells are directly killed by cytotoxic CD4+ T cells in a perforin/granzyme B-dependent manner. By contrast, MHCIINEG myeloma cells are killed by IFN-g stimulated M1-like macrophages. In summary, while the priming phase of CD4+ T cells appears similar for MHCIIPOS and MHCIINEG tumors, the killing mechanisms are different. Unresolved issues and directions for future research are addressed.

  18. Trans-species polymorphism of the Mhc class II DRB-like gene in banded penguins (genus Spheniscus).

    Science.gov (United States)

    Kikkawa, Eri F; Tsuda, Tomi T; Sumiyama, Daisuke; Naruse, Taeko K; Fukuda, Michio; Kurita, Masanori; Wilson, Rory P; LeMaho, Yvon; Miller, Gary D; Tsuda, Michio; Murata, Koichi; Kulski, Jerzy K; Inoko, Hidetoshi

    2009-05-01

    The Major Histocompatibility Complex (Mhc) class II DRB locus of vertebrates is highly polymorphic and some alleles may be shared between closely related species as a result of balancing selection in association with resistance to parasites. In this study, we developed a new set of PCR primers to amplify, clone, and sequence overlapping portions of the Mhc class II DRB-like gene from the 5'UTR end to intron 3, including exons 1, 2, and 3 and introns 1 and 2 in four species (20 Humboldt, six African, five Magellanic, and three Galapagos penguins) of penguin from the genus Spheniscus (Sphe). Analysis of gene sequence variation by the neighbor-joining method of 21 Sphe sequences and 20 previously published sequences from four other penguin species revealed overlapping clades within the Sphe species, but species-specific clades for the other penguin species. The overlap of the DRB-like gene sequence variants between the four Sphe species suggests that, despite their allopatric distribution, the Sphe species are closely related and that some shared DRB1 alleles may have undergone a trans-species inheritance because of balancing selection and/or recent rapid speciation. The new primers and PCR assays that we have developed for the identification of the DRB1 DNA and protein sequence variations appear to be useful for the characterization of the molecular evolution of the gene in closely related Penguin species and might be helpful for the assessment of the genetic health and the management of the conservation and captivity of these endangered species. PMID:19319519

  19. Predominant Occupation of the Class I MHC Molecule H-2Kwm7 with a Single Self-peptide Suggests a Mechanism for its Diabetes-protective Effect

    Energy Technology Data Exchange (ETDEWEB)

    Brims, D.; Qian, J; Jarchum, I; Mikesh, L; Palmieri, E; Ramagopal, U; Malashkevich, V; Chaparro, R; Lund, T; et. al.

    2010-01-01

    Type 1 diabetes (T1D) is an autoimmune disease characterized by T cell-mediated destruction of insulin-producing pancreatic {beta} cells. In both humans and the non-obese diabetic (NOD) mouse model of T1D, class II MHC alleles are the primary determinant of disease susceptibility. However, class I MHC genes also influence risk. These findings are consistent with the requirement for both CD{sup 4+} and CD{sup 8+} T cells in the pathogenesis of T1D. Although a large body of work has permitted the identification of multiple mechanisms to explain the diabetes-protective effect of particular class II MHC alleles, studies examining the protective influence of class I alleles are lacking. Here, we explored this question by performing biochemical and structural analyses of the murine class I MHC molecule H-2K{sup wm7}, which exerts a diabetes-protective effect in NOD mice. We have found that H-2K{sup wm7} molecules are predominantly occupied by the single self-peptide VNDIFERI, derived from the ubiquitous protein histone H2B. This unexpected finding suggests that the inability of H-2K{sup wm7} to support T1D development could be due, at least in part, to the failure of peptides from critical {beta}-cell antigens to adequately compete for binding and be presented to T cells. Predominant presentation of a single peptide would also be expected to influence T-cell selection, potentially leading to a reduced ability to select a diabetogenic CD{sup 8+} T-cell repertoire. The report that one of the predominant peptides bound by T1D-protective HLA-A*31 is histone derived suggests the potential translation of our findings to human diabetes-protective class I MHC molecules.

  20. Accurate approximation method for prediction of class I MHC affinities for peptides of length 8, 10 and 11 using prediction tools trained on 9mers

    DEFF Research Database (Denmark)

    Lundegaard, Claus; Lund, Ole; Nielsen, Morten

    2008-01-01

    Several accurate prediction systems have been developed for prediction of class I major histocompatibility complex (MHC):peptide binding. Most of these are trained on binding affinity data of primarily 9mer peptides. Here, we show how prediction methods trained on 9mer data can be used for accurate...

  1. FOXP1 suppresses immune response signatures and MHC class II expression in activated B-cell-like diffuse large B-cell lymphomas

    DEFF Research Database (Denmark)

    Brown, P J; Wong, K K; Felce, S L;

    2016-01-01

    The FOXP1 (forkhead box P1) transcription factor is a marker of poor prognosis in diffuse large B-cell lymphoma (DLBCL). Here microarray analysis of FOXP1-silenced DLBCL cell lines identified differential regulation of immune response signatures and major histocompatibility complex class II (MHC ...

  2. Survival of ovarian cancer patients overexpressing the tumour antigen p53 is diminished in case of MHC class I down-regulation

    NARCIS (Netherlands)

    Leffers, Ninke; Lambeck, Annechien J. A.; de Graeff, Pauline; Bijlsma, Astrid Y.; Daemen, Toos; van der Zee, Ate G. J.; Nijman, Hans W.

    2008-01-01

    Objectives. The adaptive immune system seems to play an essential role in the natural course of ovarian cancer. Aim of this study was to establish whether disease-specific survival for patients expressing the tumour antigen p53 is influenced by MHC class I expression or the presence of p53 autoantib

  3. Cryopreservation of MHC multimers

    DEFF Research Database (Denmark)

    Hadrup, Sine Reker; Maurer, Dominik; Laske, Karoline;

    2015-01-01

    and long-term storage is generally not recommended. We investigated here the possibility of cryopreserving MHC multimers, both in-house produced and commercially available, using a wide range of peptide-MHC class I multimers comprising virus and cancer-associated epitopes of different affinities...... presented by various HLA-class I molecules. Cryopreservation of MHC multimers was feasible for at least 6 months, when they were dissolved in buffer containing 5-16% glycerol (v/v) and 0.5% serum albumin (w/v). The addition of cryoprotectants was tolerated across three different T-cell staining protocols...

  4. Experimental validation of multi-epitope peptides including promising MHC class I- and class II-restricted epitopes of four known Leishmania infantum proteins

    Directory of Open Access Journals (Sweden)

    Maria eAgallou

    2014-06-01

    Full Text Available Leishmaniasis is a significant worldwide health problem for which no vaccine exists. Activation of CD4+ and CD8+ T cells is crucial for the generation of protective immunity against parasite. Recent trend in vaccine design has been shifted to epitope-based vaccines that are more specific, safe, and easy to produce. In the present study, four known antigenic Leishmania (L. infantum proteins, CPA, histone H1, KMP-11 and LeIF were analysed for the prediction of binding epitopes to H2d MHC class I and class II molecules, using online available algorithms. Based on in silico analysis, eight peptides including highly scored MHC class I- and class II-restricted epitopes were synthesized. Peptide immunogenicity was validated in MHC compatible BALB/c mice immunized with each synthetic peptide emulsified in CFA/IFA. CPA_p2, CPA_p3, H1_p1 and LeIF_p6 induced strong spleen cell proliferation upon in vitro peptide re-stimulation. In addition, the majority of the peptides, except of LeIF_p1 and KMP-11_p1, induced IFN-γ secretion, while KMP-11_p1 indicated a suppressive effect on IL-10 production. CPA_p2, CPA_p3, LeIF_p3 and LeIF_p6 induced IFN-γ-producing CD4+ T cells indicating a TH1 type response. In addition, CPA_p2, CPA_p3 and H1_p1 induced also the induction of CD8+ T cells. The induction of peptide-specific IgG in immunized mice designated also the existence of B cell epitopes in peptide sequences. Combining immunoinformatic tools and experimental validation, we demonstrated that CPA_p2, CPA_p3, H1_p1, H1_p3, CPA_p2, LeIF_p3 and LeIF_p6 are likely to include potential epitopes for the induction of protective cytotoxic and/or TH1-type immune responses supporting the feasibility of peptide-based vaccine development for leishmaniasis.

  5. Selective pressures on MHC class II genes in the guppy (Poecilia reticulata) as inferred by hierarchical analysis of population structure.

    Science.gov (United States)

    Herdegen, M; Babik, W; Radwan, J

    2014-11-01

    Genes of the major histocompatibility complex, which are the most polymorphic of all vertebrate genes, are a pre-eminent system for the study of selective pressures that arise from host-pathogen interactions. Balancing selection capable of maintaining high polymorphism should lead to the homogenization of MHC allele frequencies among populations, but there is some evidence to suggest that diversifying selection also operates on the MHC. However, the pattern of population structure observed at MHC loci is likely to depend on the spatial and/or temporal scale examined. Here, we investigated selection acting on MHC genes at different geographic scales using Venezuelan guppy populations inhabiting four regions. We found a significant correlation between MHC and microsatellite allelic richness across populations, which suggests the role of genetic drift in shaping MHC diversity. However, compared to microsatellites, more MHC variation was explained by differences between populations within larger geographic regions and less by the differences between the regions. Furthermore, among proximate populations, variation in MHC allele frequencies was significantly higher compared to microsatellites, indicating that selection acting on MHC may increase population structure at small spatial scales. However, in populations that have significantly diverged at neutral markers, the population-genetic signature of diversifying selection may be eradicated in the long term by that of balancing selection, which acts to preserve rare alleles and thus maintain a common pool of MHC alleles.

  6. Full length cDNA cloning and sequencing of major histocompatibility complex (MHC) class I gene from Cyprinus carpio var. jian%建鲤MHC class Ⅰ基因全长cDNA的克隆与序列分析

    Institute of Scientific and Technical Information of China (English)

    周凯; 张成锋; 王建新; 李冰; 朱健

    2011-01-01

    采用同源克隆和末端快速扩增(RACE)方法克隆了建鲤(Cyprinus carpio var.jian)MHC class Ⅰ基因全长cD-NA并进行了序列分析.结果显示:实验得到了1914 bp的建鲤的MHC class Ⅰ全长cDNA序列;建鲤MHC class Ⅰ基因包括1044 bp的开放阅读框(ORF),118 bp的5'非编码区(UTR)以及752 bp的3'非编码区(UTR),含有保守的半胱氨酸残基,N-糖基化位点.氨基酸序列比对结果显示,建鲤MHC class Ⅰ与日本鲤的MHC class Ⅰ相似性最高,为66.0%;与虹鳟、大西洋鲑、青鳉、红鳍东方鲀的相似性分别为54.5%、57.9%、44.3%、42.0%,与小鼠、大鼠、人的相似性分别为29.1%、28.7%、29.7%.%Major histocompatibility complex(MHC) is one of crucial immune factors in vertebrates. The full-length eDNA of the Cyprinus carpio var. jian MHC class I that was cloned by homology cloning and RACE PCR approach is 1914 bp,The sequencing results showed that Cyprinus carpio var. jian MHC class I gene including 1044 bp ORF, 118 bp 5' terminal UTR and 752 bp 3' terminal UTR, and the conserved cysteine residues, N-glycosylation sites. The alignment result of aminoacids sequences showed that the identity between Cyprinus carpio var. jian MHC class I and Japan carp was 66. 0%which was the highest, and the identity with Oncorhynchus mykiss, Salmo salar, Oryzias latipes, Takifugu rubripes was 54.5%, 57.9%, 44.3%, 42.0%, and the identity with Mus musculus, Rattus norvegicus, Homo sapiens was only 29. 1%, 28.7%, 29. 7%, respectively.

  7. MHC-Ⅱ类抗原在角膜碱烧伤后眼组织的动态改变%MHC class Ⅱ positive cells in the eye tissue of rats after alkali burn of cornea

    Institute of Scientific and Technical Information of China (English)

    赵敏; 陈家祺; 杨培增

    2001-01-01

    目的:探讨角膜碱烧伤后角膜溃烂溶解穿孔以及眼内炎症的免疫学机制。方法:在大鼠角膜上制作碱烧伤模型,在烧伤后的不同阶段,制备角膜、虹膜、脉络膜以及视网膜铺片,采用卵白素-生物素过氧化物酶免疫组化方法(ABC法),检测眼组织MHC-Ⅱ类抗原阳性细胞。结果:烧伤初期,角膜及虹膜即有MHC-Ⅱ类抗原阳性细胞的轻度增多;在角膜溶解穿孔阶段,MHC-Ⅱ类抗原阳性细胞大量出现,密集分布于角膜缘及溃疡溶解处,以及虹膜、脉络膜组织中,且在形态学上也发生了一些变化。当烧伤后期溃疡愈合角膜病变稳定时,虹膜上依然见较多阳性细胞。正常视网膜细胞未见MHC-Ⅱ类抗原的表达,但在烧伤后角膜溶解期以及稳定期,均可见Ⅱ类抗原阳性细胞。结论:免疫反应可能参与了严重角膜碱烧伤角膜溶解及眼内炎症的病理过程,其发生机理可能与自身免疫反应有关。%Objective: To investigate immunological mechanism of corneal melting, perforation and ophthalmitis after alkali burn. Methods: A model of severe corneal alkali burn was established in rats. Immunohistochemical method (ABC method) was carried out on wholemounts of the cornea, iris, choroid and retina at different time after corneal burns to detect MHC class Ⅱ positive cells. Results: In the early stage of the burn, slight increase of the number of MHC class Ⅱ positive cells in the cornea and iris was found. At the time of corneal melting and perforation, a massive influx of the positive cells was not only seen at the limbus but also in the corneal melting area, iris and choroid. Morphological changes of the cells were also noted. In restoration stage, a number of positive cells was also found in iris. In the normal control group and in the early stage of the burn, the MHC class Ⅱ antigen was not expressed in the retina tissue, but at the the time of corneal

  8. Modified human beta 2-microglobulin (desLys(58)) displays decreased affinity for the heavy chain of MHC class I and induces nitric oxide production and apoptosis

    DEFF Research Database (Denmark)

    Wang, M; Harhaji, L; Lamberth, K;

    2009-01-01

    Beta2-microglobulin (beta2m) is the light chain of major histocompatibility complex class I (MHC-I) molecules, and is a prerequisite for the binding of peptides to the heavy chain and their presentation to CD8+ T cells. beta2m can be modified in vivo and in vitro by proteolytic cleavage...... by complement C1 and subsequent carboxypeptidase B-like activity--processes that lead to the generation of desLys(58) beta2m (dbeta2m). This work aims to study the effect of dbeta2m on peptide binding to MHC-I, the influence of dbeta2m on the binding of beta2m to the MHC-I heavy chain and the biological...... activity of dbeta2m. Both beta2m and dbeta2m are able to support the generation of MHC-I/peptide complexes at 18 degrees C, but complexes formed in the presence of dbeta2m destabilize at 37 degrees C. Moreover, a 250 times higher concentration of dbeta2m than of beta2m is needed to displace MHC...

  9. Expressão de antígenos MHC classe I e de células CD4 e CD8 na polimiosite e dermatomiosite

    Directory of Open Access Journals (Sweden)

    Carla Renata Graça

    2015-06-01

    Full Text Available Objetivo: Analisar as frequências de expressão dos antígenos de complexo principal de histocompatibilidade classe I (MHC-I e células CD4 e CD8 no músculo esquelético na polimiosite (PM e dermatomiosite (DM. Métodos: Estudo retrospectivo de 34 casos de PM, oito casos de DM e 29 controles com miopatias não inflamatórias. Resultados: Os antígenos MHC-I expressaram-se no sarcolema e/ou sarcoplasma em 79,4% dos casos de PM, 62,5% dos casos de DM e 27,6% dos controles (a expressão de CD4 foi observada em 76,5%, 75% e 13,8%, respectivamente. Quando os antígenos de MHC-I foram coexpressados com CD4, houve elevada suspeita de PM/DM (principalmente PM. Em 14,3% dos casos de PM/DM, observou-se a expressão isolada dos antígenos MHC-I, sem células inflamatórias. Conclusão: A expressão dos antígenos MHC-I e a positividade do CD4 podem aumentar a suspeita diagnóstica de PM/DM. Não foi observado infiltrado celular em 14,3% dos casos.

  10. Nonclassical antigen-processing pathways are required for MHC class II-restricted direct tumor recognition by NY-ESO-1-specific CD4(+) T cells.

    Science.gov (United States)

    Matsuzaki, Junko; Tsuji, Takemasa; Luescher, Immanuel; Old, Lloyd J; Shrikant, Protul; Gnjatic, Sacha; Odunsi, Kunle

    2014-04-01

    Tumor antigen-specific CD4(+) T cells that directly recognize cancer cells are important for orchestrating antitumor immune responses at the local tumor sites. However, the mechanisms of direct MHC class II (MHC-II) presentation of intracellular tumor antigen by cancer cells are poorly understood. We found that two functionally distinct subsets of CD4(+) T cells were expanded after HLA-DPB1*04 (DP04)-binding NY-ESO-1157-170 peptide vaccination in patients with ovarian cancer. Although both subsets recognized exogenous NY-ESO-1 protein pulsed on DP04(+) target cells, only one type recognized target cells with intracellular expression of NY-ESO-1. The tumor-recognizing CD4(+) T cells more efficiently recognized the short 8-9-mer peptides than the non-tumor-recognizing CD4(+) T cells. In addition to endosomal/lysosomal proteases that are typically involved in MHC-II antigen presentation, several pathways in the MHC class I presentation pathways, such as the proteasomal degradation and transporter-associated with antigen-processing-mediated peptide transport, were also involved in the presentation of intracellular NY-ESO-1 on MHC-II. The presentation was inhibited significantly by primaquine, a small molecule that inhibits endosomal recycling, consistent with findings that pharmacologic inhibition of new protein synthesis enhances antigen presentation. Together, our data demonstrate that cancer cells selectively present peptides from intracellular tumor antigens on MHC-II by multiple nonclassical antigen-processing pathways. Harnessing the direct tumor-recognizing ability of CD4(+) T cells could be a promising strategy to enhance antitumor immune responses in the immunosuppressive tumor microenvironment.

  11. NetMHCIIpan-3.0, a common pan-specific MHC class II prediction method including all three human MHC class II isotypes, HLA-DR, HLA-DP and HLA-DQ

    DEFF Research Database (Denmark)

    Karosiene, Edita; Rasmussen, Michael; Blicher, Thomas;

    2013-01-01

    importance for understanding the nature of immune responses and identifying T cell epitopes for the design of new vaccines and immunotherapies. Given the large number of MHC variants, and the costly experimental procedures needed to evaluate individual peptide–MHC interactions, computational predictions have...

  12. Sequence Comparison of MHC Class Ⅱβ (Exon 2) and Phylogenetic Relationship Between Poultry and Mammalian

    Institute of Scientific and Technical Information of China (English)

    XU Ri-fu; LI Kui; CHEN Guo-hong; QIANG Ba-yang-zong; MO De-lin; LI Chang-chun; FAN Bin; LIU Bang

    2005-01-01

    A fragment spanning over exon 2 and intron 2 of major histocompatibility complex B-LB Ⅱ genes was amplified using PCR,cloned and sequenced in 13 individuals from eight Chinese indigenous chicken breeds and one introduced breed. Another 41 sequences of MHC class Ⅱβ from ten vertebrate species were cited from the NCBI GenBank. Thirteen new B-LB Ⅱ alleles were found in the chicken breeds sampled. Alignment of the exon 2 sequences revealed 91.1-97.8% similarity to each other within the chickens sampled, and the chickens shared 84.1-87.0% homology to Phasianus colchicus, 78.5-81.5% similarity to Coturnixjaponica. The sequences in poultry showed 62.6-68.1% identity to HLA-DRBl, 50-61.5% similarity to DQB (HLA-, SLA- and H2-BB), 53.7-60% to HLA-DPB and 53.3-57.8% similarity to HLA-DOB. The frequency of nonsynonymous substitutions of nucleotide was higher than that of synonymous substitutions, and the frequencies of nonsynonymous and synonymous substitutions in poultry B-LB Ⅱ genes were lower than those observed in mammalian DRB1 and DQB1 genes. The deduced amino acid sequences of MHC class Ⅱβ1 domain exhibited extreme difference in conversed region and variable region patterns among the various species, but the two conserved cysteines forming disulfide-bond were shown consistent in poultry with that in mammalian species; and the carbohydrate attachment site was found more conserved in chicken, Homo sapiens, Bos taurus, Ovis aries and Capra hircus than in Sus scrofa and rodent animals. Compared with exon 2 of DQB1 genes of Homo sapiens, ruminant species and Sus scrofa, the differentia that the deletion of six nucleotides at position195 to 200 of exon 2 of DQB1 genes, and insertion of three nucleotides at position 247 to 249 of the exon 2 existed in rodent species were found, which led to the absence of three AA residues at position 65, 66,and 67 within β1 domain of DQB1 chain, and the insertion of one AA residue at position 85. The difference of the deletion

  13. Expressão do complexo de histocompatilidade principal de classe I (MHC I no sistema nervoso central: plasticidade sináptica e regeneração Expresión del complejo principal de histocompatibilidad de clase I (MHC I en el sistema nervioso central: plasticidad sináptica y regeneración Expression of class I major histocompatibility complex (MHC I in the central nervous system: role in synaptic plasticity and regeneration

    Directory of Open Access Journals (Sweden)

    Renata Graciele Zanon

    2010-06-01

    Full Text Available Foi demonstrado recentemente que o complexo de histocompatibilidade principal de classe I (MHC I, expresso no sistema nervoso central (SNC, não funciona somente como molécula com papel imunológico, mas também como parte de um mecanismo envolvido na plasticidade sináptica. A expressão de MHC I interfere na intensidade e seletividade da retração de sinapses em contato com neurônios que sofreram lesão e também influencia a reatividade das células gliais próximas a esses neurônios. A intensidade do rearranjo sináptico e resposta glial após lesão, ligadas à expressão de MHC I no SNC, repercute em diferenças na capacidade regenerativa e recuperação funcional em linhagens de camundongos isogênicos. Dessa forma, os novos aspectos sobre a função do MHC I no SNC direcionam futuras pesquisas no sentido de buscar o envolvimento do MHC I em doenças neurológicas e também o desenvolvimento de novas estratégias terapêuticas.El complejo mayor de histocompatibilidad de clase I (MHC I, expresado en el sistema nervioso central (SNC, no sólo funciona como una molécula con función inmunológica, sino que es crucial para las respuestas del tejido nervioso en casos de lesiones. El MHC I está involucrado con los procesos de plasticidad sináptica y las células gliales en el microambiente de la médula espinal después de realizada axotomía periférica. La expresión de MHC I interfiere con la intensidad y la forma en que se producen la contracción y la eliminación de sinapsis con relación a las neuronas, cuyos axones se han comprometido, y también influye en la reactividad de las células gliales, cerca de estas neuronas. La intensidad de estos cambios, que responden a la expresión de MHC I en el SNC, implica diferencias en la capacidad de regeneración axonal de las células dañadas por axotomía, por lo que el nivel de expresión de las moléculas MHC I se relaciona con el proceso de regeneración de los axones y, en

  14. Drift rather than selection dominates MHC class II allelic diversity patterns at the biogeographical range scale in natterjack toads Bufo calamita.

    Directory of Open Access Journals (Sweden)

    Inga Zeisset

    Full Text Available Study of major histocompatibility complex (MHC loci has gained great popularity in recent years, partly due to their function in protecting vertebrates from infections. This is of particular interest in amphibians on account of major threats many species face from emergent diseases such as chytridiomycosis. In this study we compare levels of diversity in an expressed MHC class II locus with neutral genetic diversity at microsatellite loci in natterjack toad (Bufo (Epidalea calamita populations across the whole of the species' biogeographical range. Variation at both classes of loci was high in the glacial refugium areas (REF and much lower in postglacial expansion areas (PGE, especially in range edge populations. Although there was clear evidence that the MHC locus was influenced by positive selection in the past, congruence with the neutral markers suggested that historical demographic events were the main force shaping MHC variation in the PGE area. Both neutral and adaptive genetic variation declined with distance from glacial refugia. Nevertheless, there were also some indications from differential isolation by distance and allele abundance patterns that weak effects of selection have been superimposed on the main drift effect in the PGE zone.

  15. HLA-G and MHC Class II Protein Expression in Diffuse Large B-Cell Lymphoma.

    Science.gov (United States)

    Jesionek-Kupnicka, Dorota; Bojo, Marcin; Prochorec-Sobieszek, Monika; Szumera-Ciećkiewicz, Anna; Jabłońska, Joanna; Kalinka-Warzocha, Ewa; Kordek, Radzisław; Młynarski, Wojciech; Robak, Tadeusz; Warzocha, Krzysztof; Lech-Maranda, Ewa

    2016-06-01

    The expression of human leukocyte antigen-G (HLA-G) and HLA class II protein was studied by immunohistochemical staining of lymph nodes from 148 patients with diffuse large B-cell lymphoma (DLBCL) and related to the clinical course of the disease. Negative HLA-G expression was associated with a lower probability of achieving a complete remission (p = 0.04). Patients with negative HLA-G expression tended towards a lower 3-year overall survival (OS) rate compared to those with positive expression of HLA-G (p = 0.08). When restricting the analysis to patients receiving chemotherapy with rituximab, the estimated 3-year OS rate of patients with positive HLA-G expression was 73.3 % compared with 47.5 % (p = 0.03) in those with negative expression. Patients with negative HLA class II expression presented a lower 3-year OS rate compared to subjects with positive expression (p = 0.04). The loss of HLA class II expression (p = 0.05) and belonging to the intermediate high/high IPI risk group (p = 0.001) independently increased the risk of death. HLA class II expression also retained its prognostic value in patients receiving rituximab; the 3-year OS rate was 65.3 % in patients with positive HLA class II expression versus 29.6 % (p = 0.04) in subjects that had loss of HLA class II expression. To our knowledge, for the first time, the expression of HLA-G protein in DLBCL and its association with the clinical course of the disease was demonstrated. Moreover, the link between losing HLA class II protein expression and poor survival of patients treated with immunochemotherapy was confirmed.

  16. Lack of association of bovine MHC class I alleles with carcass and reproductive traits.

    Science.gov (United States)

    Arriëns, M A; Hofer, A; Obexer-Ruff, G; Lazary, S

    1996-12-01

    The present study was carried out to examine whether a relationship between bovine major histocompatibility complex (BoLA) class I alleles and carcass traits or reproductive performance exists in Braunvieh and Fleckvieh AI (artificial insemination) bulls. The influence of BoLA class I (BoLA-A) alleles on deregressed breeding values for net growth rate, carcass index and thigh volume was assessed in Braunvieh crosses and Fleckvieh bulls with a gene substitution model. The reproductive traits: non-return rate and interval between first and last insemination of daughters (female fertility), as well as non-return rate of inseminated cows (male fertility), were only investigated in Fleckvieh animals. No influence of the BoLA-A region on the traits evaluated could be demonstrated. An improper, i.e. less restrictive analysis would have led to spurious results.

  17. Immunopathology of american cutaneous leishmaniasis. Modulation of MHC class II gene products by Keratinocytes before and after glucantime therapy

    Directory of Open Access Journals (Sweden)

    Claude Pirmez

    1990-06-01

    Full Text Available Epidermal changes from 32 cutaneous and 3 mucosal American leishmaniasis (ACL active lesions were studied for HLA-DR, -DP expression, Lanerhans cells and lymphocyte infiltration. In addition to a DR and DQ positivity at the surface of the cells of the inflammatory infiltrate, a strong reaction for DR antigens was detected on keratinocytes. Hyperplasia of Langerhans cells was present in al cutaneous lesions and epidermis was infiltrated by T lymphocytes. When healed lesions of 14 of these subjects were re-biopsied 1 to 12 months after the end of pentavalent antimonial therapy, MHC class antigens could no longer be seen on keratinocytes. Our data represrn evidence for hhe reversibility of the abnormal HLA-DR expression by keratinocytes in ACL after Glucantime therapy or spontaneous scar formation, demonstrating that this expresion is restricted to the period of active lesions. The present findings can be regarded as an indirect evidence that keratinocytes may be involved in the immunopathology of ACL.

  18. Crystal structure of a Gammadelta T-cell Receptor Specific for the Human MHC class I Homolog MICA

    Energy Technology Data Exchange (ETDEWEB)

    B Xu; J Pizarro; M Holmes; C McBeth; V Groh; T Spies; R Strong

    2011-12-31

    {gamma}{delta} T cells play important roles in bridging innate and adaptive immunity, but their recognition mechanisms remain poorly understood. Human {gamma}{delta} T cells of the V{sub {delta}}1 subset predominate in intestinal epithelia and respond to MICA and MICB (MHC class I chain-related, A and B; MIC) self-antigens, mediating responses to tumorigenesis or viral infection. The crystal structure of an MIC-reactive V{sub {delta}}1 {gamma}{delta} T-cell receptor (TCR) showed expected overall structural homology to antibodies, {alpha}{beta}, and other {gamma}{delta} TCRs, but complementary determining region conformations and conservation of V{sub {delta}}1 use revealed an uncharacteristically flat potential binding surface. MIC, likewise, serves as a ligand for the activating immunoreceptor natural killer group 2, D (NKG2D), also expressed on {gamma}{delta} T cells. Although MIC recognition drives both the TCR-dependent stimulatory and NKG2D-dependent costimulatory signals necessary for activation, interaction analyses showed that MIC binding by the two receptors was mutually exclusive. Analysis of relative binding kinetics suggested sequential recognition, defining constraints for the temporal organization of {gamma}{delta} T-cell/target cell interfaces.

  19. Generation of MHC class I-restricted cytotoxic T cell lines and clones against colonic epithelial cells from ulcerative colitis.

    Science.gov (United States)

    Yonamine, Y; Watanabe, M; Kinjo, F; Hibi, T

    1999-01-01

    We established CTL lines and clones against colonic epithelial cells from PBLs of patients with ulcerative colitis by continuous stimulation with HLA-A locus-matched colonic epithelial cell lines. We developed a nonradioactive europium release cytotoxicity assay to detect CTLs. PBLs from 3 of 12 patients but not from any of 14 normal controls who shared at least one haplotype of HLA-A locus with two colonic epithelial cell lines, CW2 and ACM, showed increased cytotoxicity against these lines. Three CTL lines established from the PBLs of patients showed increased cytotoxicity against HLA-A locus-matched CW2 or ACM but not against matched lung or esophagus cell lines. The phenotypes of CTL lines were alpha beta-TCR+ CD3+ CD8+ CD16-. The CTL line MS showed increased cytotoxicity against freshly isolated colonic epithelial cells but not against cells with a different HLA-A locus. Two CTL clones were generated from MS and clone 3-2, expressing CD3+ CD8+ CD4- CD56-, showed high MHC class I-restricted cytotoxicity against the colonic epithelial cells. These results indicated that CTLs against colonic epithelial cells may contribute to epithelial cell damage in ulcerative colitis. PMID:10080107

  20. Adrenomedullin 2 Improves Early Obesity-Induced Adipose Insulin Resistance by Inhibiting the Class II MHC in Adipocytes.

    Science.gov (United States)

    Zhang, Song-Yang; Lv, Ying; Zhang, Heng; Gao, Song; Wang, Ting; Feng, Juan; Wang, Yuhui; Liu, George; Xu, Ming-Jiang; Wang, Xian; Jiang, Changtao

    2016-08-01

    MHC class II (MHCII) antigen presentation in adipocytes was reported to trigger early adipose inflammation and insulin resistance. However, the benefits of MHCII inhibition in adipocytes remain largely unknown. Here, we showed that human plasma polypeptide adrenomedullin 2 (ADM2) levels were negatively correlated with HOMA of insulin resistance in obese human. Adipose-specific human ADM2 transgenic (aADM2-tg) mice were generated. The aADM2-tg mice displayed improvements in high-fat diet-induced early adipose insulin resistance. This was associated with increased insulin signaling and decreased systemic inflammation. ADM2 dose-dependently inhibited CIITA-induced MHCII expression by increasing Blimp1 expression in a CRLR/RAMP1-cAMP-dependent manner in cultured adipocytes. Furthermore, ADM2 treatment restored the high-fat diet-induced early insulin resistance in adipose tissue, mainly via inhibition of adipocyte MHCII antigen presentation and CD4(+) T-cell activation. This study demonstrates that ADM2 is a promising candidate for the treatment of early obesity-induced insulin resistance. PMID:27207558

  1. In silico peptide-binding predictions of passerine MHC class I reveal similarities across distantly related species, suggesting convergence on the level of protein function

    DEFF Research Database (Denmark)

    Follin, Elna; Karlsson, Maria; Lundegaard, Claus;

    2013-01-01

    compared to most mammals. To elucidate the reason for this large number of genes, we compared 14 MHC class I alleles (α1–α3 domains), from great reed warbler, house sparrow and tree sparrow, via phylogenetic analysis, homology modelling and in silico peptide-binding predictions to investigate...... is of functional significance. The MHC class I allomorphs from house sparrow and tree sparrow, species that diverged 10 million years ago (MYA), had overlapping peptide-binding specificities, and these similarities across species were also confirmed in phylogenetic analyses based on amino acid sequences. Notably......, there were also overlapping peptide-binding specificities in the allomorphs from house sparrow and great reed warbler, although these species diverged 30 MYA. This overlap was not found in a tree based on amino acid sequences. Our interpretation is that convergent evolution on the level of the protein...

  2. Prediction of MHC binding peptides and epitopes from alfalfa mosaic virus.

    Science.gov (United States)

    Gomase, Virendra S; Kale, Karbhari V; Chikhale, Nandkishor J; Changbhale, Smruti S

    2007-08-01

    Peptide fragments from alfalfa mosaic virus involved multiple antigenic components directing and empowering the immune system to protect the host from infection. MHC molecules are cell surface proteins, which take active part in host immune reactions and involvement of MHC class-I & II in response to almost all antigens. Coat protein of alfalfa mosaic virus contains 221 aa residues. Analysis found five MHC ligands in coat protein as 64-LSSFNGLGV-72; 86- RILEEDLIY-94; 96-MVFSITPSY-104; 100- ITPSYAGTF-108; 110- LTDDVTTED-118; having rescaled binding affinity and c-terminal cleavage affinity more than 0.5. The predicted binding affinity is normalized by the 1% fractil. The MHC peptide binding is predicted using neural networks trained on c-terminals of known epitopes. In analysis predicted MHC/peptide binding is a log transformed value related to the IC50 values in nM units. Total numbers of peptides found are 213. Predicted MHC binding regions act like red flags for antigen specific and generate immune response against the parent antigen. So a small fragment of antigen can induce immune response against whole antigen. This theme is implemented in designing subunit and synthetic peptide vaccines. The sequence analysis method allows potential drug targets to identify active sites against plant diseases. The method integrates prediction of peptide MHC class I binding; proteosomal c-terminal cleavage and TAP transport efficiency. PMID:17691913

  3. An integrative approach to CTL epitope prediction: A combined algorithm integrating MHC class I binding, TAP transport efficiency, and proteasomal cleavage predictions

    DEFF Research Database (Denmark)

    Larsen, Mette Voldby; Lundegaard, Claus; Lamberth, K;

    2005-01-01

    Reverse immunogenetic approaches attempt to optimize the selection of candidate epitopes, and thus minimize the experimental effort needed to identify new epitopes. When predicting cytotoxic T cell epitopes, the main focus has been on the highly specific MHC class I binding event. Methods have al.......The method is available at http://www.cbs.dtu.dk/services/NetCTL. Supplementary material is available at http://www.cbs.dtu.dk/suppl/immunology/CTL.php....

  4. Structural Basis for the Recognition of Mutant Self by a Tumor-Specific, MHC Class II-Restricted T Cell Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Deng,L.; Langley, R.; Brown, P.; Xu, G.; Teng, L.; Wang, Q.; Gonzales, M.; Callender, G.; Nishimura, M.; et al.

    2007-01-01

    Structural studies of complexes of T cell receptor (TCR) and peptide-major histocompatibility complex (MHC) have focused on TCRs specific for foreign antigens or native self. An unexplored category of TCRs includes those specific for self determinants bearing alterations resulting from disease, notably cancer. We determined here the structure of a human melanoma-specific TCR (E8) bound to the MHC molecule HLA-DR1 and an epitope from mutant triosephosphate isomerase. The structure had features intermediate between 'anti-foreign' and autoimmune TCR-peptide-MHC class II complexes that may reflect the hybrid nature of altered self. E8 manifested very low affinity for mutant triosephosphate isomerase-HLA-DR1 despite the highly tumor-reactive properties of E8 cells. A second TCR (G4) had even lower affinity but underwent peptide-specific formation of dimers, suggesting this as a mechanism for enhancing low-affinity TCR-peptide-MHC interactions for T cell activation.

  5. CD4 and MHC class I down-modulation activities of nef alleles from brain- and lymphoid tissue-derived primary HIV-1 isolates

    Science.gov (United States)

    Gray, Lachlan R.; Gabuzda, Dana; Cowley, Daniel; Ellett, Anne; Chiavaroli, Lisa; Wesselingh, Steven L.; Churchill, Melissa J.; Gorry, Paul R.

    2015-01-01

    HIV-1 nef undergoes adaptive evolution in the CNS, reflecting altered requirements for HIV-1 replication in macrophages/microglia and brain-specific immune selection pressures. The role of Nef in HIV-1 neurotropism and the pathogenesis of HIV-associated dementia (HAD) is unclear. In this study, we characterized 82 nef alleles cloned from brain, CSF, spinal cord and blood/lymphoid tissue-derived HIV-1 isolates from 7 subjects with HAD. CNS isolate-derived nef alleles were genetically compartmentalized and had reduced sequence diversity compared to those from lymphoid tissue isolates. Defective nef alleles predominated in a brain-derived isolate from one of the 7 subjects (MACS2-br). The ability of Nef to down-modulate CD4 and MHC class 1 (MHC-1) was generally conserved among nef alleles from both CNS and lymphoid tissues. However, the potency of CD4 and MHC-1 down-modulation was variable, which was associated with sequence alterations known to influence these Nef functions. These results suggest that CD4 and MHC-1 down-modulation are highly conserved functions among nef alleles from CNS- and lymphoid tissue-derived HIV-1 isolates that may contribute to viral replication and escape from immune surveillance in the CNS. PMID:21165790

  6. Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California.

    Science.gov (United States)

    Moreno-Santillán, Diana D; Lacey, Eileen A; Gendron, Diane; Ortega, Jorge

    2016-01-01

    The genes of the Major Histocompatibility Complex (MHC) play an important role in the vertebrate immune response and are among the most polymorphic genes known in vertebrates. In some marine mammals, MHC genes have been shown to be characterized by low levels of polymorphism compared to terrestrial taxa; this reduction in variation is often explained as a result of lower pathogen pressures in marine habitats. To determine if this same reduction in variation applies to the migratory population of blue whales (Balaenoptera musculus) that occurs in the Gulf of California, we genotyped a 172 bp fragment of exon 2 of the MHC Class II DQB locus for 80 members of this population. Twenty-two putatively functional DQB allotypes were identified, all of which were homologous with DQB sequences from other cetacean species. Up to 5 putative alleles per individual were identified, suggesting that gene duplication has occurred at this locus. Rates of non-synonymous to synonymous substitutions (ω) and maximum likelihood analyses of models of nucleotide variation provided potential evidence of ongoing positive selection at this exon. Phylogenetic analyses of DQB alleles from B. musculus and 16 other species of cetaceans revealed trans-specific conservation of MHC variants, suggesting that selection has acted on this locus over prolonged periods of time. Collectively our findings reveal that immunogenic variation in blue whales is comparable to that in terrestrial mammals, thereby providing no evidence that marine taxa are subject to reduced pathogen-induced selective pressures. PMID:26761201

  7. Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus from the Gulf of California.

    Directory of Open Access Journals (Sweden)

    Diana D Moreno-Santillán

    Full Text Available The genes of the Major Histocompatibility Complex (MHC play an important role in the vertebrate immune response and are among the most polymorphic genes known in vertebrates. In some marine mammals, MHC genes have been shown to be characterized by low levels of polymorphism compared to terrestrial taxa; this reduction in variation is often explained as a result of lower pathogen pressures in marine habitats. To determine if this same reduction in variation applies to the migratory population of blue whales (Balaenoptera musculus that occurs in the Gulf of California, we genotyped a 172 bp fragment of exon 2 of the MHC Class II DQB locus for 80 members of this population. Twenty-two putatively functional DQB allotypes were identified, all of which were homologous with DQB sequences from other cetacean species. Up to 5 putative alleles per individual were identified, suggesting that gene duplication has occurred at this locus. Rates of non-synonymous to synonymous substitutions (ω and maximum likelihood analyses of models of nucleotide variation provided potential evidence of ongoing positive selection at this exon. Phylogenetic analyses of DQB alleles from B. musculus and 16 other species of cetaceans revealed trans-specific conservation of MHC variants, suggesting that selection has acted on this locus over prolonged periods of time. Collectively our findings reveal that immunogenic variation in blue whales is comparable to that in terrestrial mammals, thereby providing no evidence that marine taxa are subject to reduced pathogen-induced selective pressures.

  8. Genetic variation of the MHC class II DRB genes in the Japanese weasel, Mustela itatsi, endemic to Japan, compared with the Siberian weasel, Mustela sibirica.

    Science.gov (United States)

    Nishita, Y; Abramov, A V; Kosintsev, P A; Lin, L-K; Watanabe, S; Yamazaki, K; Kaneko, Y; Masuda, R

    2015-12-01

    Major histocompatibility complex (MHC) genes encode proteins that play a critical role in vertebrate immune system and are highly polymorphic. To further understand the molecular evolution of the MHC genes, we compared MHC class II DRB genes between the Japanese weasel (Mustela itatsi), a species endemic to Japan, and the Siberian weasel (Mustela sibirica), a closely related species on the continent. We sequenced a 242-bp region of DRB exon 2, which encodes antigen-binding sites (ABS), and found 24 alleles from 31 M. itatsi individuals and 17 alleles from 21 M. sibirica individuals, including broadly distributed, species-specific and/or geographically restricted alleles. Our results suggest that pathogen-driven balancing selection have acted to maintain the diversity in the DRB genes. For predicted ABS, nonsynonymous substitutions exceeded synonymous substitutions, also indicating positive selection, which was not seen at non-ABS. In a Bayesian phylogenetic tree, two M. sibirica DRB alleles were basal to the rest of the sequences from mustelid species and may represent ancestral alleles. Trans-species polymorphism was evident between many mustelid DRB alleles, especially between M. itatsi and M. sibirica. These two Mustela species divided about 1.7 million years ago, but still share many MHC alleles, indicative of their close phylogenetic relationship. PMID:26593752

  9. Btn2a2, a T cell immunomodulatory molecule coregulated with MHC class II genes.

    Science.gov (United States)

    Sarter, Kerstin; Leimgruber, Elisa; Gobet, Florian; Agrawal, Vishal; Dunand-Sauthier, Isabelle; Barras, Emmanuèle; Mastelic-Gavillet, Béatris; Kamath, Arun; Fontannaz, Paola; Guéry, Leslie; Duraes, Fernanda do Valle; Lippens, Carla; Ravn, Ulla; Santiago-Raber, Marie-Laure; Magistrelli, Giovanni; Fischer, Nicolas; Siegrist, Claire-Anne; Hugues, Stéphanie; Reith, Walter

    2016-02-01

    Evidence has recently emerged that butyrophilins, which are members of the extended B7 family of co-stimulatory molecules, have diverse functions in the immune system. We found that the human and mouse genes encoding butyrophilin-2A2 (BTN2A2) are regulated by the class II trans-activator and regulatory factor X, two transcription factors dedicated to major histocompatibility complex class II expression, suggesting a role in T cell immunity. To address this, we generated Btn2a2-deficient mice. Btn2a2(-/-) mice exhibited enhanced effector CD4(+) and CD8(+) T cell responses, impaired CD4(+) regulatory T cell induction, potentiated antitumor responses, and exacerbated experimental autoimmune encephalomyelitis. Altered immune responses were attributed to Btn2a2 deficiency in antigen-presenting cells rather than T cells or nonhematopoietic cells. These results provide the first genetic evidence that BTN2A2 is a co-inhibitory molecule that modulates T cell-mediated immunity.

  10. Genome-wide association study identifies SNPs in the MHC class II loci that are associated with self-reported history of whooping cough.

    Science.gov (United States)

    McMahon, George; Ring, Susan M; Davey-Smith, George; Timpson, Nicholas J

    2015-10-15

    Whooping cough is currently seeing resurgence in countries despite high vaccine coverage. There is considerable variation in subject-specific response to infection and vaccine efficacy, but little is known about the role of human genetics. We carried out a case-control genome-wide association study of adult or parent-reported history of whooping cough in two cohorts from the UK: the ALSPAC cohort and the 1958 British Birth Cohort (815/758 cases and 6341/4308 controls, respectively). We also imputed HLA alleles using dense SNP data in the MHC region and carried out gene-based and gene-set tests of association and estimated the amount of additive genetic variation explained by common SNPs. We observed a novel association at SNPs in the MHC class II region in both cohorts [lead SNP rs9271768 after meta-analysis, odds ratio [95% confidence intervals (CIs)] 1.47 (1.35, 1.6), P-value 1.21E - 18]. Multiple strong associations were also observed at alleles at the HLA class II loci. The majority of these associations were explained by the lead SNP rs9271768. Gene-based and gene-set tests and estimates of explainable common genetic variation could not establish the presence of additional associations in our sample. Genetic variation at the MHC class II region plays a role in susceptibility to whooping cough. These findings provide additional perspective on mechanisms of whooping cough infection and vaccine efficacy.

  11. Genome-wide association study identifies SNPs in the MHC class II loci that are associated with self-reported history of whooping cough

    Science.gov (United States)

    McMahon, George; Ring, Susan M.; Davey-Smith, George; Timpson, Nicholas J.

    2015-01-01

    Whooping cough is currently seeing resurgence in countries despite high vaccine coverage. There is considerable variation in subject-specific response to infection and vaccine efficacy, but little is known about the role of human genetics. We carried out a case–control genome-wide association study of adult or parent-reported history of whooping cough in two cohorts from the UK: the ALSPAC cohort and the 1958 British Birth Cohort (815/758 cases and 6341/4308 controls, respectively). We also imputed HLA alleles using dense SNP data in the MHC region and carried out gene-based and gene-set tests of association and estimated the amount of additive genetic variation explained by common SNPs. We observed a novel association at SNPs in the MHC class II region in both cohorts [lead SNP rs9271768 after meta-analysis, odds ratio [95% confidence intervals (CIs)] 1.47 (1.35, 1.6), P-value 1.21E − 18]. Multiple strong associations were also observed at alleles at the HLA class II loci. The majority of these associations were explained by the lead SNP rs9271768. Gene-based and gene-set tests and estimates of explainable common genetic variation could not establish the presence of additional associations in our sample. Genetic variation at the MHC class II region plays a role in susceptibility to whooping cough. These findings provide additional perspective on mechanisms of whooping cough infection and vaccine efficacy. PMID:26231221

  12. Bioinformatics prediction of swine MHC class I epitopes from Porcine Reproductive and Respiratory Syndrome Virus

    DEFF Research Database (Denmark)

    Welner, Simon; Nielsen, Morten; Lund, Ole;

    of the host cell antiviral machinery, to the deceptive induction of a non-neutralizing antibody response through decoy antigen presentation. This, combined with a very high mutation rate, has hampered the development of safe and effective vaccines. With the overall aim to design a vaccine that induces...... strains of high quality. For each strain, a library of all possible 9- and 10-mer peptides was generated considering the known ribosomal frame shift sites and sites for post translational cleavage. All peptides were in silico analyzed for binding affinity to either of five common SLA class I alleles...... by the PopCover algorithm, providing a final list of 54 epitopes prioritized according to maximum coverage of PRRSV strains and SLA alleles. This bioinformatics approach provides a rational strategy for selecting peptides for a CTL-activating vaccine with broad coverage of both virus and swine diversity...

  13. Functional deficiency of MHC class I enhances LTP and abolishes LTD in the nucleus accumbens of mice.

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Edamura

    Full Text Available Major histocompatibility complex class I (MHCI molecules were recently identified as novel regulators of synaptic plasticity. These molecules are expressed in various brain areas, especially in regions undergoing activity-dependent synaptic plasticity, but their role in the nucleus accumbens (NAc is unknown. In this study, we investigated the effects of genetic disruption of MHCI function, through deletion of β2-microblobulin, which causes lack of cell surface expression of MHCI. First, we confirmed that MHCI molecules are expressed in the NAc core in wild-type mice. Second, we performed electrophysiological recordings with NAc core slices from wild-type and β2-microglobulin knock-out mice lacking cell surface expression of MHCI. We found that low frequency stimulation induced long-term depression in wild-type but not knock-out mice, whereas high frequency stimulation induced long-term potentiation in both genotypes, with a larger magnitude in knock-out mice. Furthermore, we demonstrated that knock-out mice showed more persistent behavioral sensitization to cocaine, which is a NAc-related behavior. Using this model, we analyzed the density of total AMPA receptors and their subunits GluR1 and GluR2 in the NAc core, by SDS-digested freeze-fracture replica labeling. After repeated cocaine exposure, the density of GluR1 was increased, but there was no change in total AMPA receptors and GluR2 levels in wild-type mice. In contrast, following repeated cocaine exposure, increased densities of total AMPA receptors, GluR1 and GluR2 were observed in knock-out mice. These results indicate that functional deficiency of MHCI enhances synaptic potentiation, induced by electrical and pharmacological stimulation.

  14. No major role for insulin-degrading enzyme in antigen presentation by MHC molecules.

    Directory of Open Access Journals (Sweden)

    Slobodan Culina

    Full Text Available Antigen presentation by MHC class I molecules requires degradation of epitope source proteins in the cytosol. Although the preeminent role of the proteasome is clearly established, evidence suggesting a significant role for proteasome-independent generation of class I ligands has been reported repeatedly. However, an enzyme responsible for such a role has not been identified. Recently insulin-degrading enzyme (IDE was shown to produce an antigenic peptide derived from the tumor antigen MAGE-A3 in an entirely proteasome-independent manner, raising the question of the global impact of IDE in MHC class I antigen processing. Here we report that IDE knockdown in human cell lines, or knockout in two different mouse strains, has no effect on cell surface expression of various MHC class I molecules, including allomorphs such as HLA-A3 and HLA-B27 suggested to be loaded in an at least a partly proteasome-independent manner. Moreover, reduced or absent IDE expression does not affect presentation of five epitopes including epitopes derived from beta amyloid and proinsulin, two preferred IDE substrates. Thus, IDE does not play a major role in MHC class I antigen processing, confirming the dominant and almost exclusive role of the proteasome in cytosolic production of MHC class I ligands.

  15. No major role for insulin-degrading enzyme in antigen presentation by MHC molecules.

    Science.gov (United States)

    Culina, Slobodan; Mauvais, François-Xavier; Hsu, Hsiang-Ting; Burgevin, Anne; Guénette, Suzanne; Moser, Anna; van Endert, Peter

    2014-01-01

    Antigen presentation by MHC class I molecules requires degradation of epitope source proteins in the cytosol. Although the preeminent role of the proteasome is clearly established, evidence suggesting a significant role for proteasome-independent generation of class I ligands has been reported repeatedly. However, an enzyme responsible for such a role has not been identified. Recently insulin-degrading enzyme (IDE) was shown to produce an antigenic peptide derived from the tumor antigen MAGE-A3 in an entirely proteasome-independent manner, raising the question of the global impact of IDE in MHC class I antigen processing. Here we report that IDE knockdown in human cell lines, or knockout in two different mouse strains, has no effect on cell surface expression of various MHC class I molecules, including allomorphs such as HLA-A3 and HLA-B27 suggested to be loaded in an at least a partly proteasome-independent manner. Moreover, reduced or absent IDE expression does not affect presentation of five epitopes including epitopes derived from beta amyloid and proinsulin, two preferred IDE substrates. Thus, IDE does not play a major role in MHC class I antigen processing, confirming the dominant and almost exclusive role of the proteasome in cytosolic production of MHC class I ligands.

  16. MHC class II diversity of koala (Phascolarctos cinereus) populations across their range.

    Science.gov (United States)

    Lau, Q; Jaratlerdsiri, W; Griffith, J E; Gongora, J; Higgins, D P

    2014-10-01

    Major histocompatibility complex class II (MHCII) genes code for proteins that bind and present antigenic peptides and trigger the adaptive immune response. We present a broad geographical study of MHCII DA β1 (DAB) and DB β1 (DBB) variants of the koala (Phascolarctos cinereus; n=191) from 12 populations across eastern Australia, with a total of 13 DAB and 7 DBB variants found. We identified greater MHCII variation and, possibly, additional gene copies in koala populations in the north (Queensland and New South Wales) relative to the south (Victoria), confirmed by STRUCTURE analyses and genetic differentiation using analysis of molecular variance. The higher MHCII diversity in the north relative to south could potentially be attributed to (i) significant founder effect in Victorian populations linked to historical translocation of bottlenecked koala populations and (ii) increased pathogen-driven balancing selection and/or local genetic drift in the north. Low MHCII genetic diversity in koalas from the south could reduce their potential response to disease, although the three DAB variants found in the south had substantial sequence divergence between variants. This study assessing MHCII diversity in the koala with historical translocations in some populations contributes to understanding the effects of population translocations on functional genetic diversity.

  17. Yeast surface display of a noncovalent MHC class II heterodimer complexed with antigenic peptide.

    Science.gov (United States)

    Boder, Eric T; Bill, Jerome R; Nields, Andrew W; Marrack, Philippa C; Kappler, John W

    2005-11-20

    Microbial protein display technologies have enabled directed molecular evolution of binding and stability properties in numerous protein systems. In particular, dramatic improvements to antibody binding affinity and kinetics have been accomplished using these tools in recent years. Examples of successful application of display technologies to other immunological proteins have been limited to date. Herein, we describe the expression of human class II major histocompatibility complex allele (MHCII) HLA-DR4 on the surface of Saccharomyces cerevisiae as a noncovalently associated heterodimer. The yeast-displayed MHCII is fully native as assessed by binding of conformationally specific monoclonal antibodies; failure of antibodies specific for empty HLA-DR4 to bind yeast-displayed protein indicates antigenic peptide is bound. This report represents the first example of a noncovalent protein dimer displayed on yeast and of successful display of wild-type MHCII. Results further point to the potential for using yeast surface display for engineering and analyzing the antigen binding properties of MHCII.

  18. Linkage of bacterial protein synthesis and presentation of MHC class I-restricted Listeria monocytogenes-derived antigenic peptides.

    Directory of Open Access Journals (Sweden)

    Silke Grauling-Halama

    Full Text Available The processing and MHC class I-restricted presentation of antigenic peptides derived from the p60 protein of the facultative intracellular bacterium Listeria monocytogenes is tightly linked to bacterial protein synthesis. We used non-linear regression analysis to fit a mathematical model of bacterial antigen processing to a published experimental data set showing the accumulation and decay of p60-derived antigenic peptides in L. monocytogenes-infected cells. Two alternative models equally describe the experimental data. The simulation accounting for a stable and a hypothetical rapidly degraded form of antigen predicts that the antigenic peptides p60 217-225 and p60 449-457 are derived from a putative instable form of p60 with an average intracellular half-life of approximately 3 minutes accounting for approximately 31% of all p60 molecules synthesized. The alternative model predicts that both antigenic peptides are processed from p60 degraded intracellularly with a half-life of 109 min and that antigen processing only occurs as long as bacterial protein synthesis is not inhibited. In order to decide between both models the intracellular accumulation of p60 in infected cells was studied experimentally and compared with model predictions. Inhibition of p60 degradation by the proteasome inhibitor epoxomicin revealed that during the first 3 h post infection approximately 30% of synthesized p60 molecules were degraded. This value is significantly lower than the approximately 50% degradation of p60 that would be expected in the presence of the predicted putative short-lived state of p60 and also fits precisely with the predictions of the alternative model, indicating that the tight connection of bacterial protein biosynthesis and antigen processing and presentation of L. monocyctogenes-derived antigenic peptides is not caused by the presence of a highly instable antigenic substrate.

  19. Ultra-deep Illumina sequencing accurately identifies MHC class IIb alleles and provides evidence for copy number variation in the guppy (Poecilia reticulata).

    Science.gov (United States)

    Lighten, Jackie; van Oosterhout, Cock; Paterson, Ian G; McMullan, Mark; Bentzen, Paul

    2014-07-01

    We address the bioinformatic issue of accurately separating amplified genes of the major histocompatibility complex (MHC) from artefacts generated during high-throughput sequencing workflows. We fit observed ultra-deep sequencing depths (hundreds to thousands of sequences per amplicon) of allelic variants to expectations from genetic models of copy number variation (CNV). We provide a simple, accurate and repeatable method for genotyping multigene families, evaluating our method via analyses of 209 b of MHC class IIb exon 2 in guppies (Poecilia reticulata). Genotype repeatability for resequenced individuals (N = 49) was high (100%) within the same sequencing run. However, repeatability dropped to 83.7% between independent runs, either because of lower mean amplicon sequencing depth in the initial run or random PCR effects. This highlights the importance of fully independent replicates. Significant improvements in genotyping accuracy were made by greatly reducing type I genotyping error (i.e. accepting an artefact as a true allele), which may occur when using low-depth allele validation thresholds used by previous methods. Only a small amount (4.9%) of type II error (i.e. rejecting a genuine allele as an artefact) was detected through fully independent sequencing runs. We observed 1-6 alleles per individual, and evidence of sharing of alleles across loci. Variation in the total number of MHC class II loci among individuals, both among and within populations was also observed, and some genotypes appeared to be partially hemizygous; total allelic dosage added up to an odd number of allelic copies. Collectively, observations provide evidence of MHC CNV and its complex basis in natural populations.

  20. Doxorubicin-conjugated bacteriophages carrying anti-MHC class I chain-related A for targeted cancer therapy in vitro

    Directory of Open Access Journals (Sweden)

    Phumyen A

    2014-11-01

    . Dox-phage was more efficient than free drugs in killing all the cell lines tested. The half maximal inhibitory concentration (IC50 values of Dox-phage were lower than those of free drugs at approximately 1.6–6 times depending on MICA expressions and the cell lines tested. Conclusion: Evidently, the application of 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide chemistry is effective to conjugate doxorubicin and major coat protein of bacteriophages without destroying binding activity of MICA antibodies. Dox-carrying bacteriophages targeting MICA have been successfully developed and may enable a broad range of applications in cancer-targeting chemotherapy. Keywords: MHC class I chain–related A (MICA, phage display, doxorubicin, targeted therapy

  1. A four-step model for the IL-6 amplifier, a regulator of chronic inflammations in tissue-specific MHC class II-associated autoimmune diseases.

    Science.gov (United States)

    Murakami, Masaaki; Hirano, Toshio

    2011-01-01

    It is commonly thought that autoimmune diseases are caused by the breakdown of self-tolerance, which suggests the recognition of specific antigens by autoreactive CD4+ T cells contribute to the specificity of autoimmune diseases (Marrack et al., 2001; Mathis and Benoist, 2004). In several cases, however, even for diseases associated with class II major histocompatibility complex (MHC) alleles, the causative tissue-specific antigens recognized by memory/activated CD4+ T cells have not been established (Mocci et al., 2000; Skapenko et al., 2005). Rheumatoid arthritis (RA) and arthritis in F759 knock-in mice (F759 mice) are such examples (Atsumi et al., 2002; Brennan et al., 2002; Falgarone et al., 2009). These include associations with class II MHC and CD4 molecules; increased numbers of memory/activated CD4+ T cells; and improved outcomes in response to suppressions and/or deficiencies in class II MHC molecules, CD4+ T cells, and the T cell survival cytokine IL-7. Regarding the development of arthritis in F759 mice, it is not only the immune system, but also non-immune tissue that are involved, indicating that the importance of their interactions (Sawa et al., 2006, 2009; Ogura et al., 2008; Hirano, 2010; Murakami et al., 2011). Furthermore, we have shown that local events such as microbleeding together with an accumulation of activated CD4+ T cells in a manner independent of tissue antigen-recognitions induces arthritis in the joints of F759 mice (Murakami et al., 2011). For example, local microbleeding-mediated CCL20 expression induce such an accumulation, causing arthritis development via chronic activation of an IL-17A-dependent IL-6 signaling amplification loop in type 1 collagen+ cells that is triggered by CD4+ T cell-derived cytokine(s) such as IL-17A, which leads to the synergistic activation of STAT3 and NFκB in non-hematopoietic cells in the joint (Murakami et al., 2011). We named this loop the IL-6-mediated inflammation amplifier, or IL-6 amplifier for

  2. MHC class I signaling in T cells leads to tyrosine kinase activity and PLC-gamma 1 phosphorylation

    DEFF Research Database (Denmark)

    Skov, S; Odum, Niels; Claesson, M H

    1995-01-01

    phosphorylation and the subsequent calcium response. The early tyrosine kinase activity was found to be dependent on expression of the TCR/CD3 complex and the CD45 molecule on the surface of the T cells. Furthermore, MHC-I cross-linking was shown to tyrosine phosphorylate PLC-gamma 1 (phospholipase C-gamma 1...

  3. Changes in variation at the MHC class II DQA locus during the final demise of the woolly mammoth

    Science.gov (United States)

    Pečnerová, Patrícia; Díez-Del-Molino, David; Vartanyan, Sergey; Dalén, Love

    2016-05-01

    According to the nearly-neutral theory of evolution, the relative strengths of selection and drift shift in favour of drift at small population sizes. Numerous studies have analysed the effect of bottlenecks and small population sizes on genetic diversity in the MHC, which plays a central role in pathogen recognition and immune defense and is thus considered a model example for the study of adaptive evolution. However, to understand changes in genetic diversity at loci under selection, it is necessary to compare the genetic diversity of a population before and after the bottleneck. In this study, we analyse three fragments of the MHC DQA gene in woolly mammoth samples radiocarbon dated to before and after a well-documented bottleneck that took place about ten thousand years ago. Our results indicate a decrease in observed heterozygosity and number of alleles, suggesting that genetic drift had an impact on the variation on MHC. Based on coalescent simulations, we found no evidence of balancing selection maintaining MHC diversity during the Holocene. However, strong trans-species polymorphism among mammoths and elephants points to historical effects of balancing selection on the woolly mammoth lineage.

  4. The properties of the single chicken MHC classical class II alpha chain ( B-LA) gene indicate an ancient origin for the DR/E-like isotype of class II molecules

    DEFF Research Database (Denmark)

    Salomonsen, Jan; Marston, Denise; Avila, David;

    2003-01-01

    significantly in the peptide-binding alpha(1) domain. The cDNA and genomic DNA sequences from chickens of diverse origins show few alleles, which differ in only four nucleotides and one amino acid. In contrast, significant restriction fragment length polymorphism is detected by Southern blot analysis of genomic...... DNA, suggesting considerable diversity around the gene. Analysis of a large back-cross family indicates that the class II alpha chain locus ( B-LA) is located roughly 5.6 cM from the MHC locus, which encodes the classical class II beta chains. Thus the chicken class II alpha chain gene is like the...

  5. Patterns of MHC-G-Like and MHC-B Diversification in New World Monkeys.

    Directory of Open Access Journals (Sweden)

    Juan S Lugo

    Full Text Available The MHC class I (MHC-I region in New World monkeys (Platyrrhini has remained relatively understudied. To evaluate the diversification patterns and transcription behavior of MHC-I in Platyrrhini, we first analyzed public genomic sequences from the MHC-G-like subregion in Saimiri boliviensis, Ateles geoffroyi and Callicebus moloch, and from the MHC-B subregion in Saimiri boliviensis. While S. boliviensis showed multiple copies of both MHC-G-like (10 and -B (15 loci, A. geoffroyi and C. moloch had only three and four MHC-G-like genes, respectively, indicating that not all Platyrrhini species have expanded their MHC-I loci. We then sequenced MHC-G-like and -B cDNAs from nine Platyrrhini species, recovering two to five unique cDNAs per individual for both loci classes. In two Saguinus species, however, no MHC-B cDNAs were found. In phylogenetic trees, MHC-G-like cDNAs formed genus-specific clusters whereas the MHC-B cDNAs grouped by Platyrrhini families, suggesting a more rapid diversification of the former. Furthermore, cDNA sequencing in 12 capuchin monkeys showed that they transcribe at least four MHC-G-like and five MHC-B polymorphic genes, showing haplotypic diversity for gene copy number and signatures of positive natural selection at the peptide binding region. Finally, a quantitative index for MHC:KIR affinity was proposed and tested to predict putative interacting pairs. Altogether, our data indicate that i MHC-I genes has expanded differentially among Platyrrhini species, ii Callitrichinae (tamarins and marmosets MHC-B loci have limited or tissue-specific expression, iii MHC-G-like genes have diversified more rapidly than MHC-B genes, and iv the MHC-I diversity is generated mainly by genetic polymorphism and gene copy number variation, likely promoted by natural selection for ligand binding.

  6. MHC class II super-enhancer increases surface expression of HLA-DR and HLA-DQ and affects cytokine production in autoimmune vitiligo.

    Science.gov (United States)

    Cavalli, Giulio; Hayashi, Masahiro; Jin, Ying; Yorgov, Daniel; Santorico, Stephanie A; Holcomb, Cherie; Rastrou, Melinda; Erlich, Henry; Tengesdal, Isak W; Dagna, Lorenzo; Neff, C Preston; Palmer, Brent E; Spritz, Richard A; Dinarello, Charles A

    2016-02-01

    Genetic risk for autoimmunity in HLA genes is most often attributed to structural specificity resulting in presentation of self-antigens. Autoimmune vitiligo is strongly associated with the MHC class II region. Here, we fine-map vitiligo MHC class II genetic risk to three SNPs only 47 bp apart, located within a predicted super-enhancer in an intergenic region between HLA-DRB1 and HLA-DQA1, localized by a genome-wide association study of 2,853 Caucasian vitiligo patients. The super-enhancer corresponds to an expression quantitative trait locus for expression of HLA-DR and HLA-DQ RNA; we observed elevated surface expression of HLA-DR (P = 0.008) and HLA-DQ (P = 0.02) on monocytes from healthy subjects homozygous for the high-risk SNP haplotype. Unexpectedly, pathogen-stimulated peripheral blood mononuclear cells from subjects homozygous for the high-risk super-enhancer haplotype exhibited greater increase in production of IFN-γ and IL-1β than cells from subjects homozygous for the low-risk haplotype. Specifically, production of IFN-γ on stimulation of dectin-1, mannose, and Toll-like receptors with Candida albicans and Staphylococcus epidermidis was 2.5- and 2.9-fold higher in high-risk subjects than in low-risk subjects, respectively (P = 0.007 and P = 0.01). Similarly, production of IL-1β was fivefold higher in high-risk subjects than in low-risk subjects (P = 0.02). Increased production of immunostimulatory cytokines in subjects carrying the high-risk haplotype may act as an "adjuvant" during the presentation of autoantigens, tying together genetic variation in the MHC with the development of autoimmunity. This study demonstrates that for risk of autoimmune vitiligo, expression level of HLA class II molecules is as or more important than antigen specificity.

  7. 扬子鳄种群MHC Ⅱ类B基因第3外元多态性分析%Polymorphism of Exon 3 of MHC Class Ⅱ B Gene in Chinese Alligator (Alligator sinensis)

    Institute of Scientific and Technical Information of China (English)

    刘辉; 吴孝兵; 晏鹏; 蒋志刚

    2007-01-01

    The polymorphism of MHC class Ⅱ B gene in 14 Chinese alligators was analyzed, which came from three different areas: a wild population from Xuancheng, Anhui, a captive population from Changxing, Zhejiang, and a captive population from Anhui Research Center for Reproduction of Chinese Alligators. The gene fragment was amplified using a pair of specific primers designed from the MHC gene sequence of the spectacled caiman. A total of 34 sequence haplotypes of exon 3 were detected in the sampled Chinese alligators. The numbers of haplotypes of the 3 Chinese alligator populations were 15, 10, and 9, respectively. The overall estimation of the MHC polymorphism in the Chinese alligator population was higher than those in mammals and in cyprinid fish. The rates of nonsynonymous substitutions (dN) occurred at a significantly lower frequency than that of synonymous substitutions (ds), which were not consistent with the common rule. This result might suggest that the polymorphism of exon 3 seemed not to be maintained by the balancing selection. The neutrality test of Tajima excluded the null hypothesis that the polymorphism of exon 3 was generated by a random drift, and the fact that D = -0.401 indicated an excess of rare mutations in the Chinese alligator.The nucleotide diversity of the sequences and the phylogenetic relations were also analyzed, and the results suggested that there was no significant difference in genetic diversity among the 3 populations of Chinese alligator.%分析了取自安徽宣城野生种群、安徽省扬子鳄繁殖研究中心和浙江长兴养殖种群的14条扬子鳄MHCⅡ类B基因第3外元的多态性.在这些扬子鳄样本中共检测到34个单倍型,每个亚种群内检测到的单倍型数量分别为15,9和10个,与其他一些动物如哺乳动物和鲤科鱼类相比,扬子鳄MHC Ⅱ类B基因第3外元多态性较高.另外,非同义替换率显著小于同义替换率,这可能表明扬子鳄种群MHC Ⅱ类B基因第3外元

  8. Metabolic perturbation sensitizes human breast cancer to NK cell-mediated cytotoxicity by increasing the expression of MHC class I chain-related A/B

    OpenAIRE

    Fu, Dexue; Geschwind, Jean-Francois; Karthikeyan, Swathi; Miller, Eliyahu; Kunjithapatham, Rani; Wang, Zhijun; Ganapathy-Kanniappan, Shanmugasundaram

    2015-01-01

    Cleavage or shedding of the surface antigen, MHC class I chain-related (MIC) protein (A/B) has been known to be one of the mechanisms by which tumor cells escape host immune surveillance. Thus, any strategy to augment the surface expression of MICA/B could facilitate anticancer immune response. Here, we demonstrate that metabolic perturbation by the glycolytic inhibitor, 3-bromopyruvate (3-BrPA) augments the surface expression of MICA/B in human breast cancer cell lines, MDA-MB-231 and T47D. ...

  9. Purification of correctly oxidized MHC class I heavy-chain molecules under denaturing conditions: a novel strategy exploiting disulfide assisted protein folding

    DEFF Research Database (Denmark)

    Ferré, Henrik; Ruffet, Emmanuel; Blicher, Thomas;

    2003-01-01

    The aim of this study has been to develop a strategy for purifying correctly oxidized denatured major histocompability complex class I (MHC-I) heavy-chain molecules, which on dilution, fold efficiently and become functional. Expression of heavy-chain molecules in bacteria results in the formation...... of insoluble cellular inclusion bodies, which must be solubilized under denaturing conditions. Their subsequent purification and refolding is complicated by the fact that (1). correct folding can only take place in combined presence of beta(2)-microglobulin and a binding peptide; and (2). optimal in vitro...

  10. Purification of correctly oxidized MHC class I heavy-chain molecules under denaturing conditions: A novel strategy exploiting disulfide assisted protein folding

    DEFF Research Database (Denmark)

    Ferré, Henrik; Ruffet, E.; Blicher, T.;

    2003-01-01

    The aim of this study has been to develop a strategy for purifying correctly oxidized denatured major histocompability complex class I (MHC-I) heavy-chain molecules, which on dilution, fold efficiently and become functional. Expression of heavy-chain molecules in bacteria results in the formation...... of insoluble cellular inclusion bodies, which must be solubilized under denaturing conditions. Their subsequent purification and refolding is complicated by the fact that (1) correct folding can only take place in combined presence of beta(2)-microglobulin and a binding peptide; and (2) optimal in vitro...

  11. Development of an MHC class I Ld-restricted PSA peptide-loaded tetramer for detection of PSA-specific CD8+ T cells in the mouse

    OpenAIRE

    Lemke, Caitlin D.; Graham, Jessica B.; Lubaroff, David M.; Salem, Aliasger K.

    2011-01-01

    Objectives We set out to develop a prostate specific antigen (PSA) peptide-loaded tetramer for enumeration of PSA-specific CD8+ T cells in the Balb/c mouse model. Methods A candidate MHC class I PSA peptide (HPQKVTKFML188–197) was selected based on its ability to restimulate PSA-specific CD8+ T cells to secrete IFN-γ in our assays. Next, H-2Ld-restricted peptide-loaded and fluorescently labeled tetramers were produced in conjunction with the NIH Tetramer Core Facility. This tetramer was then ...

  12. 凹耳蛙MHC Ⅱ类B基因第二外显子多态性分析%Polymorphism of exon 2 of MHC Class Ⅱ B gene in the Chinese concave-eared torrent frog (Odorrana tormota)

    Institute of Scientific and Technical Information of China (English)

    李方; 疏义林; 吴海龙

    2012-01-01

    Currently, amphibians are experiencing global population decline, and it is believed that several amphibian mass extinction events were caused by environmental pathogens (such as chytrid fungus). Major histocompatibility complex (MHC) genes play a critical role in the course of immune response in all jawed vertebrates. MHC gene is considered to be one of the best candidates to analyze animal's adaptive evolution because its polymorphisms are usually associated with resistance or susceptibility to animal diseases. Here, we report our preliminary research on the allelic diversity of MHC class II B gene from the Chinese concave-eared frog (Odorrana tormota), a species endemic to eastern China. We initially amplified a 180-bp fragment of MHC II exon2 gene in O. Tormota using published polymerase chain reaction primers. Based on these results, we successfully obtained sequences of the gene's flanking regions using a ligation-mediated PCR method. After splicing, we obtained a sequence with length of 2,030 bp including whole exon2 and partial sequences of intronl and intron2. Then two exon2-specific primers (IIQ1BU/IIQ1BD) were designed forthe species and were used to investigate the B gene diversity of a wild population (Huangshan Mt., ?=32) using PCR, cloning and sequencing. In total, 34 distinct alleles were obtained and 2 to 5 alleles were found per individual. The proportion of variable sites for nucleotide and amino acid sequences across the 34 alleles was 16.17% (33/204) and 26.87% (18/67), respectively, and the majority of variable amino acids were located in antigen binding sites (ABS). Based on cDNA data and individual allelic diversity, we conclude that O. Tormota possesses at least three class II B loci. These results showed that though the species exhibits a restricted distribution, the Chinese concave-eared frog displays high diversity at the B loci compared to that of other species in Ranidae. Patterns of nucleotide substitution exhibited the signature of

  13. Simian and Human Immunodeficiency Virus Nef Proteins Use Different Surfaces To Downregulate Class I Major Histocompatibility Complex Antigen Expression

    OpenAIRE

    Swigut, Tomek; Iafrate, A. John; Muench, Jan; Kirchhoff, Frank; Skowronski, Jacek

    2000-01-01

    Simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV-1) Nef proteins are related regulatory proteins that share several functions, including the ability to downregulate class I major histocompatibility complex (MHC) and CD4 expression on the cell surface and to alter T-cell-receptor-initiated signal transduction in T cells. We compared the mechanisms used by SIV mac239 Nef and HIV-1 Nef to downregulate class I MHC and found that the ability of SIV Nef to downregula...

  14. Epigenetic mechanisms regulate MHC and antigen processing molecules in human embryonic and induced pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Beatriz Suárez-Alvarez

    Full Text Available BACKGROUND: Human embryonic stem cells (hESCs are an attractive resource for new therapeutic approaches that involve tissue regeneration. hESCs have exhibited low immunogenicity due to low levels of Mayor Histocompatibility Complex (MHC class-I and absence of MHC class-II expression. Nevertheless, the mechanisms regulating MHC expression in hESCs had not been explored. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed the expression levels of classical and non-classical MHC class-I, MHC class-II molecules, antigen-processing machinery (APM components and NKG2D ligands (NKG2D-L in hESCs, induced pluripotent stem cells (iPSCs and NTera2 (NT2 teratocarcinoma cell line. Epigenetic mechanisms involved in the regulation of these genes were investigated by bisulfite sequencing and chromatin immunoprecipitation (ChIP assays. We showed that low levels of MHC class-I molecules were associated with absent or reduced expression of the transporter associated with antigen processing 1 (TAP-1 and tapasin (TPN components in hESCs and iPSCs, which are involved in the transport and load of peptides. Furthermore, lack of beta2-microglobulin (beta2m light chain in these cells limited the expression of MHC class I trimeric molecule on the cell surface. NKG2D ligands (MICA, MICB were observed in all pluripotent stem cells lines. Epigenetic analysis showed that H3K9me3 repressed the TPN gene in undifferentiated cells whilst HLA-B and beta2m acquired the H3K4me3 modification during the differentiation to embryoid bodies (EBs. Absence of HLA-DR and HLA-G expression was regulated by DNA methylation. CONCLUSIONS/SIGNIFICANCE: Our data provide fundamental evidence for the epigenetic control of MHC in hESCs and iPSCs. Reduced MHC class I and class II expression in hESCs and iPSCs can limit their recognition by the immune response against these cells. The knowledge of these mechanisms will further allow the development of strategies to induce tolerance and improve stem cell

  15. Adaptor protein complexes AP-1 and AP-3 are required by the HHV-7 Immunoevasin U21 for rerouting of class I MHC molecules to the lysosomal compartment.

    Directory of Open Access Journals (Sweden)

    Lisa A Kimpler

    Full Text Available The human herpesvirus-7 (HHV-7 U21 gene product binds to class I major histocompatibility complex (MHC molecules and reroutes them to a lysosomal compartment. Trafficking of integral membrane proteins to lysosomes is mediated through cytoplasmic sorting signals that recruit heterotetrameric clathrin adaptor protein (AP complexes, which in turn mediate protein sorting in post-Golgi vesicular transport. Since U21 can mediate rerouting of class I molecules to lysosomes even when lacking its cytoplasmic tail, we hypothesize the existence of a cellular protein that contains the lysosomal sorting information required to escort class I molecules to the lysosomal compartment. If such a protein exists, we expect that it might recruit clathrin adaptor protein complexes as a means of lysosomal sorting. Here we describe experiments demonstrating that the μ adaptins from AP-1 and AP-3 are involved in U21-mediated trafficking of class I molecules to lysosomes. These experiments support the idea that a cellular protein(s is necessary for U21-mediated lysosomal sorting of class I molecules. We also examine the impact of transient versus chronic knockdown of these adaptor protein complexes, and show that the few remaining μ subunits in the cells are eventually able to reroute class I molecules to lysosomes.

  16. Functional role of HLA class I cell-surface molecules in human T-lymphocyte activation and proliferation.

    OpenAIRE

    Taylor, D S; Nowell, P C; Kornbluth, J

    1986-01-01

    This investigation addressed the role of major histocompatibility complex-encoded class I molecules in the activation and proliferation of human lymphocytes. We studied the effect of antibodies specific for HLA-A and HLA-B locus gene products on mitogen-stimulated peripheral blood mononuclear cell (PBMC) subpopulations. Three individually derived, well-characterized anti-HLA class I monoclonal antibodies were demonstrated to inhibit the proliferation of human PBMC stimulated by either OKT3 or...

  17. miR-9 modulates the expression of interferon-regulated genes and MHC class I molecules in human nasopharyngeal carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fei; Zhao, Zun-Lan; Zhao, Wen-Tao; Fan, Quan-Rong; Wang, Sheng-Chun; Li, Jing; Zhang, Yu-Qing; Shi, Jun-Wen; Lin, Xiao-Lin; Yang, Sheng; Xie, Rao-Ying [Cancer Research Institute, Southern Medical University, Guangzhou 510515 (China); Liu, Wei [Institute of Comparative Medicine and Laboratory Animal Center, Southern Medical University, Guangzhou 510515 (China); Zhang, Ting-Ting; Sun, Yong-Liang [Cancer Research Institute, Southern Medical University, Guangzhou 510515 (China); Xu, Kang, E-mail: xukang1995@yahoo.com [Department of General Surgery, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou 510120 (China); Yao, Kai-Tai, E-mail: Yaokaitai@yahoo.com.cn [Cancer Research Institute, Southern Medical University, Guangzhou 510515 (China); Xiao, Dong, E-mail: Xiao_d@hotmail.com [Cancer Research Institute, Southern Medical University, Guangzhou 510515 (China); Institute of Comparative Medicine and Laboratory Animal Center, Southern Medical University, Guangzhou 510515 (China)

    2013-02-15

    Highlights: ► miR-9 can negatively or positively modulate interferon-induced gene expression. ► miR-9 can up-regulate major histocompatibility complex class I molecule expression. ► miR-9 can down-regulate the expression of interleukin-related genes. -- Abstract: The functions of miR-9 in some cancers are recently implicated in regulating proliferation, epithelial–mesenchymal transition (EMT), invasion and metastasis, apoptosis, and tumor angiogenesis, etc. miR-9 is commonly down-regulated in nasopharyngeal carcinoma (NPC), but the exact roles of miR-9 dysregulation in the pathogenesis of NPC remains unclear. Therefore, we firstly used miR-9-expressing CNE2 cells to determine the effects of miR-9 overexpression on global gene expression profile by microarray analysis. Microarray-based gene expression data unexpectedly demonstrated a significant number of up- or down-regulated immune- and inflammation-related genes, including many well-known interferon (IFN)-induced genes (e.g., IFI44L, PSMB8, IRF5, PSMB10, IFI27, PSB9{sub H}UMAN, IFIT2, TRAIL, IFIT1, PSB8{sub H}UMAN, IRF1, B2M and GBP1), major histocompatibility complex (MHC) class I molecules (e.g., HLA-B, HLA-C, HLA-F and HLA-H) and interleukin (IL)-related genes (e.g., IL20RB, GALT, IL7, IL1B, IL11, IL1F8, IL1A, IL6 and IL7R), which was confirmed by qRT-PCR. Moreover, the overexpression of miR-9 with the miRNA mimics significantly up- or down-regulated the expression of above-mentioned IFN-inducible genes, MHC class I molecules and IL-related genes; on the contrary, miR-9 inhibition by anti-miR-9 inhibitor in CNE2 and 5–8F cells correspondingly decreased or increased the aforementioned immune- and inflammation-related genes. Taken together, these findings demonstrate, for the first time, that miR-9 can modulate the expression of IFN-induced genes and MHC class I molecules in human cancer cells, suggesting a novel role of miR-9 in linking inflammation and cancer, which remains to be fully characterized.

  18. A four step model for the IL-6 amplifier, a regulator of chromic inflammations in tissue specific MHC class II-associated autoimmune diseases

    Directory of Open Access Journals (Sweden)

    Masaaki eMurakami

    2011-06-01

    Full Text Available It is thought autoimmune diseases are caused by the breakdown of self-tolerance, which suggests the recognition of specific antigens by autoreactive CD4+ T cells contribute to the specificity of autoimmune diseases. In several cases, however, even for diseases associated with class II MHC alleles, the causative tissue-specific antigens recognized by memory/activated CD4+ T cells have not been established. Rheumatoid arthritis (RA and arthritis in F759 knock-in mouse line (F759 mice are such examples, even though evidences support a pathogenic role for CD4+ T cells in both diseases. We have recently shown local events such as microbleeding together with an accumulation of activated CD4+ T cells in a manner independent of tissue antigen-recognitions induces arthritis in the joints of F759 mice. For example, local microbleeding-mediated CCL20 expression induced such an accumulation, causing arthritis development via chronic activation of an IL-17A-dependent IL-6 signaling amplification loop in type 1 collagen+ cells that is triggered by CD4+ T cell-derived cytokine(s such as IL-17A, which leads to the synergistic activation of STAT3 and NFκB in non hematopoietic cells in the joint. We named this loop the IL-6-mediated inflammation amplifier, or IL-6 amplifier. Thus, certain class II MHC–associated, tissue-specific autoimmune diseases may be induced by local events that cause an antigen-independent accumulation of effector CD4+ T cells followed by the induction of the IL-6 amplifier in the affected tissue. To explain this hypothesis, we have proposed a Four Step Model for MHC class II associated autoimmune diseases. The interaction of four local events results in chronic activation of the IL-6 amplifier, leading to the manifestation of autoimmune diseases. Thus, we have concluded the IL-6 amplifier is a critical regulator of chromic inflammations in tissue specific MHC class II-associated autoimmune diseases.

  19. Normal HLA class I, II, and MICA gene distribution in uveal melanoma.

    NARCIS (Netherlands)

    Metzelaar-Blok, J.A.; Hurks, H.M.; Naipal, A.; Lange, P. de; Keunen, J.E.E.; Claas, F.; Doxiadis, I.I.; Jager, M.J.

    2005-01-01

    PURPOSE: The molecules of the HLA class I and II molecules as well as the MHC class I chain-related gene A (MICA), a polymorphic and stress-induced cell surface molecule, are involved in T-cell and natural killer-cell (NK-cell) mediated immune responses. In this study we looked for any genetic susce

  20. Construction of MHC class Ⅱ transactivator recombinant adenovirus vector%MHC Ⅱ类转激活因子基因的重组腺病毒载体的构建

    Institute of Scientific and Technical Information of China (English)

    张敏敏; 杨骅; 金晶; 吴红玉; 李兆申

    2009-01-01

    Objective To construct a recombinant adenovirus vector containing the gene of major histocompatibility complex(MHC)class Ⅱ transactivator(C Ⅱ TA).Methods The restriction fragment of CIITA was inserted into pUC57 vector with EeoR Ⅰ and Xho Ⅰ.Then,recombinant plasmid pShutde-GFP-CMV CⅡTA was constructed with EcoR Ⅰ and Sal Ⅰ,and was confirmed by restriction enzyme digestion and sequeneing.After the treatment with Ⅰ-Ceu Ⅰ and Ⅰ-See Ⅰ,the fragment C Ⅱ TA from recombinant plasmid DShuttle-GFP-CMV.CⅡTA Was inserted into vector pAdxsi.And the pAdxsi-GFP-C Ⅱ TA wag packed into liposome,and was transfected to 293 cens.Results Recombinant plasmid pShuttle-GFP-CMV-C Ⅱ TA Was constructed successfully. After packed into vector pAdxsi, and transfected to 293 cells, significant virus Dlaques were observed,which showed the successful homologous recombination.The titer of the purified AdC Ⅱ TA was 2.0×10~(11) PFU/ml.Conclusions Recombinant adenovirus AdC Ⅱ TA containing gene of MHC class Ⅱ transactivator was established successfully.%目的 构建含有主要组织相容性复合物(major histocompatibility complex,MHC)Ⅱ类分子激活物(CⅡTA)基因的重组腺病毒载体.方法 回收CⅡTA的PCR产物插人pUC57中,用EcoR Ⅰ和Xho Ⅰ双酶切,U-Gene凝胶回收纯化3300bp目的基因片段.用EcoR Ⅰ和sal Ⅰ双酶切质粒载体pShuttle-GFP-CMV,用T4DNA连接酶将上述目的基因片段与pShuttle-GFP-CMV片段连接,得到穿梭质粒pShuttle-GFP-CMV-C Ⅱ TA,并经Kpn Ⅰ单酶切及测序鉴定.Ⅰ-Ceu Ⅰ/Ⅰ-See Ⅰ双酶切处理,回收目的片段,将pAdxsi载体片段和插入片段进行酶连接,得到腺病毒质粒pAdxsi-GFP-C Ⅱ TA,经Xho Ⅰ酶切鉴定后转染HEK293细胞并培养出毒.扩增、纯化重组腺病毒AdCⅡTA,并测定病毒滴度.结果 重组穿梭质粒pShuttle-GFP-CMV-C ⅡTA经Kpn Ⅰ单酶切及测序分析,证实与GeneBank中公布的小鼠CⅡTA(NM_007575)序列完全相

  1. Lysis of pig endothelium by IL-2 activated human natural killer cells is inhibited by swine and human major histocompatibility complex (MHC) class I gene products.

    Science.gov (United States)

    Itescu, S; Artrip, J H; Kwiatkowski, P A; Wang, S F; Minanov, O P; Morgenthau, A S; Michler, R E

    1997-01-01

    We have previously described a form of xenograft rejection, mediated by natural killer (NK) cells, occurring in pig-to-primate organ transplants beyond the period of antibody-mediated hyperacute rejection. In this study, two distinct NK activation pathways were identified as mechanisms of pig aortic endotheliual cell (PAEC) lysis by human NK cells. Using an antibody-dependent cellular cytotoxicity (ADCC) assay, a progressive increase in human NK lysis of PAEC was observed following incubation with human IgG at increasing serum titer. In the absence of IgG, a second mechanism of PAEC lysis by human NK cells was observed following activation with IL-2. IL-2 activation of human NK cells increased lysis of PAEC by over 3-fold compared with ADCC. These results indicate that IL-2 activation of human NK cells induces significantly higher levels of lytic activity than does conventional ADCC involving IgG and FcRIII. We next investigated the role of MHC class I molecules in the regulation of NK lysis following IL-2 activation. PAEC expression of SLA class I molecules was increased by up to 75% by treatment with human TNFa. Following treatment with TNFa at 1 u/ml, IL-2 activated human NK lysis of PAEC was inhibited at every effector:target (E:T) ratio tested. Maximal effect occurred at an E:T ratio of 10:1, with TNFa inhibiting specific lysis by 59% (p < 0.01). Incubation with an anti-SLA class I Mab, but not IgG isotype control, abrogated the protective effects of TNFa on NK lysis of PAEC, suggesting direct inhibitory effects of SLA class I molecules on human NK function. To investigate whether human MHC class I molecules might have similar effects on human NK lysis of PAEC, further experiments were performed using a soluble peptide derived from the alpha-helical region of HLA-B7. Incubation with the HLA-B7 derived peptide significantly reduced the IL-2 activated NK lytic activity against PAEC in a dose-dependent fashion. Maximal effect occurred at a concentration of 10 mg

  2. Cloning of a new {open_quotes}finger{close_quotes} protein gene (ZNF173) within the class I region of the human MHC

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.W.; Capossela, A.; Coleman, R. [Yale Univ. School of Medicine, New Haven, CT (United States)] [and others

    1995-09-01

    The human major histocompatibility complex contains genes of both immune and nonimmune importance. Recently, several genes encoding novel, non-HLA products have been described in this area. We have performed positional cloning of short fragment cDNA sequences from the class I region of the human MHC using a hybridization selection approach. This report describes isolation of full-length cDNA clones and partial genomic clones that encode a protein that contains two domains rich in cysteine and histidine similar to those characteristic of metal-dependent DNA binding proteins (C3HC4). The predicted protein also contains a domain thought to form a coiled-coil that may promote dimerization. A third feature is a polyglutamic acid region near the carboxyl terminus of the conceptual protein. Because of these properties, we have named this gene product acid finger protein (AFP). Although the biological role of AFP is unknown at present, one potential function is binding of nucleic acids. The gene (ZNF173) is expressed in multiple tissues and is conserved among mammals. In particular, the mouse and human coding regions are highly conserved. In addition to AFP, other related sequences have been localized to the MHC, suggesting that multiple AFP-like genes exist in this area. 50 refs., 8 figs., 1 tab.

  3. Microsatellite allele 5 of MHC class I chain-related gene a increases the risk for insulin-dependent diabetes mellitus in latvians.

    Science.gov (United States)

    Shtauvere-Brameus, A; Ghaderi, M; Rumba, I; Sanjeevi, C B

    2002-04-01

    Insulin-dependent diabetes mellitus (IDDM) is one of the most common chronic diseases. It is an autoimmune, polygenic disease, associated with several genes on different chromosomes. The most important gene is human leukocyte antigen (HLA), also known as major histocompatibility complex (MHC), which is located on chromosome 6p21.3. HLA-DQ8/DR4 and DQ2/DR3 are positively associated with IDDM and DQ6 is negatively associated with IDDM in most Caucasian populations. The MICA gene is located in the MHC class I region and is expressed by monocytes, keratinocytes, and endothelial cells. Sequence determination of the MICA gene identifies 5 alleles with 4, 5, 6, and 9 repetitions of GCT or 5 repetitions of GCT with 1 additional insertion (GGCT), and the alleles are referred to as A4, A5, A5.1, A6, and A9. Analysis of allele distribution among 93 Latvian IDDM patients and 108 healthy controls showed that allele A5 of MICA is significantly increased in IDDM patients [33/93 (35%)] compared to healthy controls [22/108 (20%)] (OR = 2.15; P = 0.016). In conclusion, we believe that MICA may play an important role in the etiopathogenesis of IDDM.

  4. CD40-CD40 ligand (CD154) engagement is required but not sufficient for modulating MHC class I, ICAM-1 and Fas expression and proliferation of human non-small cell lung tumors.

    Science.gov (United States)

    Yamada, M; Shiroko, T; Kawaguchi, Y; Sugiyama, Y; Egilmez, N K; Chen, F A; Bankert, R B

    2001-05-15

    To determine the possible functional significance of CD40 expression on human non-small cell lung carcinomas and to assess the potential of CD40 as a therapeutic target, 18 lung tumor cell lines were established from biopsy tissues and were monitored for phenotypic changes on the cell surface and alterations in tumor cell proliferation after the ligation of CD40 with a trimeric fusion protein complex of CD40 ligand (CD40Lt). CD40 cross-linking resulted in up to a 6-fold increase in the surface expression of major histocompatibility complex (MHC) class I, Fas and intracellular adhesion molecule (ICAM)-1 in a subset of tumors expressing the highest levels of CD40. Suppression of tumor proliferation was seen after the ligation of CD40 on CD40Lt-responsive cell lines. The suppression was dose dependent, reversible and resulted from a delay of the tumor cells entering S-phase. No change in the cell phenotype or in proliferation were observed in CD40-negative tumors or in tumors expressing moderate-to-low levels of CD40 after incubation with CD40Lt. CD40-negative tumors transfected with the CD40 gene expressed high levels of CD40 on their surface, but were also unresponsive to CD40Lt cross-linking of CD40. Our data establish that CD40 is required (but not sufficient) for transducing a signal that results in phenotypic changes in human lung tumors and suppression in their proliferation. We conclude that CD40 on non-small cell lung tumors may represent a potential therapeutic target, but only on a subset of the CD40+ tumors.

  5. A combined prediction strategy increases identification of peptides bound with high affinity and stability to porcine MHC class I molecules SLA-1*04:01, SLA-2*04:01, and SLA-3*04:01.

    Science.gov (United States)

    Pedersen, Lasse Eggers; Rasmussen, Michael; Harndahl, Mikkel; Nielsen, Morten; Buus, Søren; Jungersen, Gregers

    2016-02-01

    Affinity and stability of peptides bound by major histocompatibility complex (MHC) class I molecules are important factors in presentation of peptides to cytotoxic T lymphocytes (CTLs). In silico prediction methods of peptide-MHC binding followed by experimental analysis of peptide-MHC interactions constitute an attractive protocol to select target peptides from the vast pool of viral proteome peptides. We have earlier reported the peptide binding motif of the porcine MHC-I molecules SLA-1*04:01 and SLA-2*04:01, identified by an ELISA affinity-based positional scanning combinatorial peptide library (PSCPL) approach. Here, we report the peptide binding motif of SLA-3*04:01 and combine two prediction methods and analysis of both peptide binding affinity and stability of peptide-MHC complexes to improve rational peptide selection. Using a peptide prediction strategy combining PSCPL binding matrices and in silico prediction algorithms (NetMHCpan), peptide ligands from a repository of 8900 peptides were predicted for binding to SLA-1*04:01, SLA-2*04:01, and SLA-3*04:01 and validated by affinity and stability assays. From the pool of predicted peptides for SLA-1*04:01, SLA-2*04:01, and SLA-3*04:01, a total of 71, 28, and 38% were binders with affinities below 500 nM, respectively. Comparison of peptide-SLA binding affinity and complex stability showed that peptides of high affinity generally, but not always, produce complexes of high stability. In conclusion, we demonstrate how state-of-the-art prediction and in vitro immunology tools in combination can be used for accurate selection of peptides for MHC class I binding, hence providing an expansion of the field of peptide-MHC analysis also to include pigs as a livestock experimental model.

  6. Distribution of class ii major histocompatibility complex antigenexpressing cells in human dental pulp with carious lesions

    OpenAIRE

    Tetiana Haniastuti

    2012-01-01

    Background: Dental caries is a bacterial infection which causes destruction of the hard tissues of the tooth. Exposure of the dentin to the oral environment as a result of caries inevitably results in a cellular response in the pulp. The major histocompatibility complex (MHC) is a group of genes that code for cell-surface histocompatibility antigens. Cells expressing class II MHC molecules participate in the initial recognition and the processing of antigenic substances to serve as antigen-pr...

  7. Molecular regulation of MHC class I chain-related protein A expression after HDAC-inhibitor treatment of Jurkat T cells

    DEFF Research Database (Denmark)

    Andresen, Lars; Jensen, Helle; Pedersen, Marianne T;

    2007-01-01

    In this study, we characterize the molecular signal pathways that lead to MHC class I chain-related protein A (MICA) expression after histone deacetylase (HDAC)-inhibitor (HDAC-i) treatment of Jurkat T cells. Chelating calcium with BAPTA-AM or EGTA potently inhibited HDAC- and CMV-mediated MICA...... inhibit p65 expression by siRNA, it did not modify MICA/B expression. To identify important elements in MICA regulation, we made a promoter construct consisting of approximately 3 kb of the proximal MICA promoter in front of GFP. Deletion analysis showed that a germinal center-box containing a putative Sp......1 site from position -113 to -93 relative to the mRNA start site was important for HDAC and CMV-induced promoter activity. Sp1 was subsequently shown to be important, as targeted mutation of the Sp1 binding sequence or siRNA mediated down modulation of Sp1-inhibited MICA promoter activity...

  8. Analysis of endogenous peptides bound by soluble MHC class I molecules: a novel approach for identifying tumor-specific antigens.

    Science.gov (United States)

    Barnea, Eilon; Beer, Ilan; Patoka, Renana; Ziv, Tamar; Kessler, Ofra; Tzehoval, Esther; Eisenbach, Lea; Zavazava, Nicholas; Admon, Arie

    2002-01-01

    The Human MHC Project aims at comprehensive cataloging of peptides presented within the context of different human leukocyte antigens (HLA) expressed by cells of various tissue origins, both in health and in disease. Of major interest are peptides presented on cancer cells, which include peptides derived from tumor antigens that are of interest for immunotherapy. Here, HLA-restricted tumor-specific antigens were identified by transfecting human breast, ovarian and prostate tumor cell lines with truncated genes of HLA-A2 and HLA-B7. Soluble HLA secreted by these cell lines were purified by affinity chromatography and analyzed by nano-capillary electrospray ionization-tandem mass spectrometry. Typically, a large peptide pool was recovered and sequenced including peptides derived from MAGE-B2 and mucin and other new tumor-derived antigens that may serve as potential candidates for immunotherapy. PMID:11782012

  9. HLA-DRB1*11 and variants of the MHC class II locus are strong risk factors for systemic juvenile idiopathic arthritis.

    Science.gov (United States)

    Ombrello, Michael J; Remmers, Elaine F; Tachmazidou, Ioanna; Grom, Alexei; Foell, Dirk; Haas, Johannes-Peter; Martini, Alberto; Gattorno, Marco; Özen, Seza; Prahalad, Sampath; Zeft, Andrew S; Bohnsack, John F; Mellins, Elizabeth D; Ilowite, Norman T; Russo, Ricardo; Len, Claudio; Hilario, Maria Odete E; Oliveira, Sheila; Yeung, Rae S M; Rosenberg, Alan; Wedderburn, Lucy R; Anton, Jordi; Schwarz, Tobias; Hinks, Anne; Bilginer, Yelda; Park, Jane; Cobb, Joanna; Satorius, Colleen L; Han, Buhm; Baskin, Elizabeth; Signa, Sara; Duerr, Richard H; Achkar, J P; Kamboh, M Ilyas; Kaufman, Kenneth M; Kottyan, Leah C; Pinto, Dalila; Scherer, Stephen W; Alarcón-Riquelme, Marta E; Docampo, Elisa; Estivill, Xavier; Gül, Ahmet; de Bakker, Paul I W; Raychaudhuri, Soumya; Langefeld, Carl D; Thompson, Susan; Zeggini, Eleftheria; Thomson, Wendy; Kastner, Daniel L; Woo, Patricia

    2015-12-29

    Systemic juvenile idiopathic arthritis (sJIA) is an often severe, potentially life-threatening childhood inflammatory disease, the pathophysiology of which is poorly understood. To determine whether genetic variation within the MHC locus on chromosome 6 influences sJIA susceptibility, we performed an association study of 982 children with sJIA and 8,010 healthy control subjects from nine countries. Using meta-analysis of directly observed and imputed SNP genotypes and imputed classic HLA types, we identified the MHC locus as a bona fide susceptibility locus with effects on sJIA risk that transcended geographically defined strata. The strongest sJIA-associated SNP, rs151043342 [P = 2.8 × 10(-17), odds ratio (OR) 2.6 (2.1, 3.3)], was part of a cluster of 482 sJIA-associated SNPs that spanned a 400-kb region and included the class II HLA region. Conditional analysis controlling for the effect of rs151043342 found that rs12722051 independently influenced sJIA risk [P = 1.0 × 10(-5), OR 0.7 (0.6, 0.8)]. Meta-analysis of imputed classic HLA-type associations in six study populations of Western European ancestry revealed that HLA-DRB1*11 and its defining amino acid residue, glutamate 58, were strongly associated with sJIA [P = 2.7 × 10(-16), OR 2.3 (1.9, 2.8)], as was the HLA-DRB1*11-HLA-DQA1*05-HLA-DQB1*03 haplotype [6.4 × 10(-17), OR 2.3 (1.9, 2.9)]. By examining the MHC locus in the largest collection of sJIA patients assembled to date, this study solidifies the relationship between the class II HLA region and sJIA, implicating adaptive immune molecules in the pathogenesis of sJIA.

  10. HLA-DRB1*11 and variants of the MHC class II locus are strong risk factors for systemic juvenile idiopathic arthritis

    Science.gov (United States)

    Ombrello, Michael J.; Remmers, Elaine F.; Tachmazidou, Ioanna; Grom, Alexei; Foell, Dirk; Haas, Johannes-Peter; Martini, Alberto; Gattorno, Marco; Özen, Seza; Prahalad, Sampath; Zeft, Andrew S.; Bohnsack, John F.; Mellins, Elizabeth D.; Ilowite, Norman T.; Russo, Ricardo; Len, Claudio; Hilario, Maria Odete E.; Oliveira, Sheila; Yeung, Rae S. M.; Rosenberg, Alan; Wedderburn, Lucy R.; Anton, Jordi; Schwarz, Tobias; Hinks, Anne; Bilginer, Yelda; Park, Jane; Cobb, Joanna; Satorius, Colleen L.; Han, Buhm; Baskin, Elizabeth; Signa, Sara; Duerr, Richard H.; Achkar, J. P.; Kamboh, M. Ilyas; Kaufman, Kenneth M.; Kottyan, Leah C.; Pinto, Dalila; Scherer, Stephen W.; Alarcón-Riquelme, Marta E.; Docampo, Elisa; Estivill, Xavier; Gül, Ahmet; de Bakker, Paul I. W.; Raychaudhuri, Soumya; Langefeld, Carl D.; Thompson, Susan; Zeggini, Eleftheria; Thomson, Wendy; Kastner, Daniel L.; Woo, Patricia

    2015-01-01

    Systemic juvenile idiopathic arthritis (sJIA) is an often severe, potentially life-threatening childhood inflammatory disease, the pathophysiology of which is poorly understood. To determine whether genetic variation within the MHC locus on chromosome 6 influences sJIA susceptibility, we performed an association study of 982 children with sJIA and 8,010 healthy control subjects from nine countries. Using meta-analysis of directly observed and imputed SNP genotypes and imputed classic HLA types, we identified the MHC locus as a bona fide susceptibility locus with effects on sJIA risk that transcended geographically defined strata. The strongest sJIA-associated SNP, rs151043342 [P = 2.8 × 10−17, odds ratio (OR) 2.6 (2.1, 3.3)], was part of a cluster of 482 sJIA-associated SNPs that spanned a 400-kb region and included the class II HLA region. Conditional analysis controlling for the effect of rs151043342 found that rs12722051 independently influenced sJIA risk [P = 1.0 × 10−5, OR 0.7 (0.6, 0.8)]. Meta-analysis of imputed classic HLA-type associations in six study populations of Western European ancestry revealed that HLA-DRB1*11 and its defining amino acid residue, glutamate 58, were strongly associated with sJIA [P = 2.7 × 10−16, OR 2.3 (1.9, 2.8)], as was the HLA-DRB1*11—HLA-DQA1*05—HLA-DQB1*03 haplotype [6.4 × 10−17, OR 2.3 (1.9, 2.9)]. By examining the MHC locus in the largest collection of sJIA patients assembled to date, this study solidifies the relationship between the class II HLA region and sJIA, implicating adaptive immune molecules in the pathogenesis of sJIA. PMID:26598658

  11. Human NK cells selective targeting of colon cancer-initiating cells: A role for natural cytotoxicity receptors and MHC class i molecules

    KAUST Repository

    Tallerico, Rossana

    2013-01-23

    Tumor cell populations have been recently proposed to be composed of two compartments: tumor-initiating cells characterized by a slow and asymmetrical growth, and the "differentiated" cancer cells with a fast and symmetrical growth. Cancer stem cells or cancer-initiating cells (CICs) play a crucial role in tumor recurrence. The resistance of CICs to drugs and irradiation often allows them to survive traditional therapy. NK cells are potent cytotoxic lymphocytes that can recognize tumor cells. In this study, we have analyzed the NK cell recognition of tumor target cells derived from the two cancer cell compartments of colon adenocarcinoma lesions. Our data demonstrate that freshly purified allogeneic NK cells can recognize and kill colorectal carcinoma- derived CICs whereas the non-CIC counterpart of the tumors (differentiated tumor cells), either autologous or allogeneic, is less susceptible to NK cells. This difference in the NK cell susceptibility correlates with higher expression on CICs of ligands for NKp30 and NKp44 in the natural cytotoxicity receptor (NCR) group of activating NK receptors. In contrast, CICs express lower levels of MHC class I, known to inhibit NK recognition, on their surface than do the "differentiated" tumor cells. These data have been validated by confocal microscopy where NCR ligands and MHC class I molecule membrane distribution have been analyzed. Moreover, NK cell receptor blockade in cytotoxicity assays demonstrates that NCRs play a major role in the recognition of CIC targets. This study strengthens the idea that biology-based therapy harnessing NK cells could be an attractive opportunity in solid tumors. Copyright © 2013 by The American Association of Immunologists, Inc. All rights reserved.

  12. Understanding MHC class I presentation of viral antigens by human dendritic cells as a basis for rational design of therapeutic vaccines

    Directory of Open Access Journals (Sweden)

    Nadine eVan Montfoort

    2014-04-01

    Full Text Available Effective viral clearance requires the induction of virus-specific CD8+ cytotoxic T lymphocytes (CTL. Since dendritic cells (DC have a central role in initiating and shaping virus-specific CTL responses, it is important to understand how DC initiate virus-specific CTL responses. Some viruses can directly infect DC, which theoretically allows direct presentation of viral antigens to CTL, but many viruses target other cells than DC and thus the host depends on the cross-presentation of viral antigens by DC to activate virus-specific CTL.Research in mouse models has highly enhanced our understanding of the mechanisms underlying cross-presentation and the DC subsets involved, however, these results cannot be readily translated towards the role of human DC in MHC class I antigen presentation of human viruses. Here, we summarize the insights gained in the past 20 years on MHC class I presentation of viral antigen by human DC and add to the current debate on the capacities of different human DC subsets herein. Furthermore, possible sources of viral antigens and essential DC characteristics for effective induction of virus-specific CTL are evaluated.We conclude that cross-presentation is not only an efficient mechanism exploited by DC to initiate immunity to viruses that do not infect DC but also to viruses that do infect DC, because cross-presentation has many conceptual advantages and bypasses direct immune modulatory effects of the virus on its infected target cells. Since knowledge on the mechanism of viral antigen presentation and the preferred DC subsets is crucial for rational vaccine design, the obtained insights are very instrumental for the development of effective anti-viral immunotherapy.

  13. A versatile class of cell surface directional motors gives rise to gliding motility and sporulation in Myxococcus xanthus.

    Directory of Open Access Journals (Sweden)

    Morgane Wartel

    2013-12-01

    Full Text Available Eukaryotic cells utilize an arsenal of processive transport systems to deliver macromolecules to specific subcellular sites. In prokaryotes, such transport mechanisms have only been shown to mediate gliding motility, a form of microbial surface translocation. Here, we show that the motility function of the Myxococcus xanthus Agl-Glt machinery results from the recent specialization of a versatile class of bacterial transporters. Specifically, we demonstrate that the Agl motility motor is modular and dissociates from the rest of the gliding machinery (the Glt complex to bind the newly expressed Nfs complex, a close Glt paralogue, during sporulation. Following this association, the Agl system transports Nfs proteins directionally around the spore surface. Since the main spore coat polymer is secreted at discrete sites around the spore surface, its transport by Agl-Nfs ensures its distribution around the spore. Thus, the Agl-Glt/Nfs machineries may constitute a novel class of directional bacterial surface transporters that can be diversified to specific tasks depending on the cognate cargo and machinery-specific accessories.

  14. Structural basis of diverse peptide accommodation by the rhesus macaque MHC class I molecule Mamu-B*17: insights into immune protection from simian immunodeficiency virus.

    Science.gov (United States)

    Wu, Yan; Gao, Feng; Liu, Jun; Qi, Jianxun; Gostick, Emma; Price, David A; Gao, George F

    2011-12-15

    The MHC class I molecule Mamu-B*17 has been associated with elite control of SIV infection in rhesus macaques, akin to the protective effects described for HLA-B*57 in HIV-infected individuals. In this study, we determined the crystal structures of Mamu-B*17 in complex with eight different peptides corresponding to immunodominant SIV(mac)239-derived CD8(+) T cell epitopes: HW8 (HLEVQGYW), GW10 (GSHLEVQGYW), MW9 (MHPAQTSQW), QW9 (QTSQWDDPW), FW9 (FQWMGYELW), MF8 (MRHVLEPF), IW9 (IRYPKTFGW), and IW11 (IRYPKTFGWLW). The structures reveal that not only P2, but also P1 and P3, can be used as N-terminal anchor residues by Mamu-B*17-restricted peptides. Moreover, the N-terminal anchor residues exhibit a broad chemical specificity, encompassing basic (H and R), bulky polar aliphatic (Q), and small (T) residues. In contrast, Mamu-B*17 exhibits a very narrow preference for aromatic residues (W and F) at the C terminus, similar to that displayed by HLA-B*57. Flexibility within the whole peptide-binding groove contributes to the accommodation of these diverse peptides, which adopt distinct conformations. Furthermore, the unusually large pocket D enables compensation from other peptide residues if P3 is occupied by an amino acid with a small side chain. In addition, residues located at likely TCR contact regions present highly flexible conformations, which may impact TCR repertoire profiles. These findings provide novel insights into the structural basis of diverse peptide accommodation by Mamu-B*17 and highlight unique atomic features that might contribute to the protective effect of this MHC I molecule in SIV-infected rhesus macaques. PMID:22084443

  15. Negative staining and immunoelectron microscopy of adhesion-deficient mutants of Streptococcus salivarius reveal that the adhesive protein antigens are separate classes of cell surface fibril.

    Science.gov (United States)

    Weerkamp, A H; Handley, P S; Baars, A; Slot, J W

    1986-01-01

    The subcellular distribution of the cell wall-associated protein antigens of Streptococcus salivarius HB, which are involved in specific adhesive properties of the cells, was studied. Mutants which had lost the adhesive properties and lacked the antigens at the cell surface were compared with the parent strain. Immunoelectron microscopy of cryosections of cells labeled with affinity-purified, specific antisera and colloidal gold-protein A complexes was used to locate the antigens. Antigen C (AgC), a glycoprotein involved in attachment to host surfaces, was mainly located in the fibrillar layer outside the cell wall. A smaller amount of label was also found throughout the cytoplasmic area in the form of small clusters of gold particles, which suggests a macromolecular association. Mutant HB-7, which lacks the wall-associated AgC, accumulated AgC reactivity intracellularly. Intracellular AgC was often found associated with isolated areas of increased electron density, but sometimes seemed to fill the entire interior of the cell. Antigen B (AgB), a protein responsible for interbacterial coaggregation, was also located in the fibrillar layer, although its distribution differed from that of the wall-associated AgC since AgB was found predominantly in the peripheral areas. A very small amount of label was also found in the cytoplasmic area as discrete gold particles. Mutant HB-V5, which lacks wall-associated AgB, was not labeled in the fibrillar coat, but showed the same weak intracellular label as the parent strain. Immunolabeling with serum against AgD, another wall-associated protein but of unknown function, demonstrated its presence in the fibrillar layer of strain HB. Negatively stained preparations of whole cells of wild-type S. salivarius and mutants that had lost wall-associated AgB or AgC revealed that two classes of short fibrils are carried on the cell surface at the same time. AgB and AgC are probably located on separate classes of short, protease

  16. MHC class II molecules deliver costimulatory signals in human T cells through a functional linkage with IL-2-receptors

    DEFF Research Database (Denmark)

    Odum, Niels; Kanner, S B; Ledbetter, J A;

    1993-01-01

    a regulatory function in T cell activation. Here, we show that cross-linking HLA-DR and -DP but not -DQ molecules by immobilized mAb enhanced proliferative T cell responses to IL-2. In contrast, class II stimulation had no effect on IL-4-induced proliferation. The costimulatory effect was most......Ab induced tyrosine phosphorylation of specific substrates including PLC-gamma 1. Combined stimulation of IL-2R and class II molecules had an additive effect on tyrosine phosphorylation. Pretreatment of T cells with a protein tyrosine kinase inhibitor, herbimycin A, inhibited IL-2 and class II...

  17. MHC class II/ESO tetramer-based generation of in vitro primed anti-tumor T-helper lines for adoptive cell therapy of cancer.

    Science.gov (United States)

    Poli, Caroline; Raffin, Caroline; Dojcinovic, Danijel; Luescher, Immanuel; Ayyoub, Maha; Valmori, Danila

    2013-02-01

    Generation of tumor-antigen specific CD4(+) T-helper (T(H)) lines through in vitro priming is of interest for adoptive cell therapy of cancer, but the development of this approach has been limited by the lack of appropriate tools to identify and isolate low frequency tumor antigen-specific CD4(+) T cells. Here, we have used recently developed MHC class II/peptide tetramers incorporating an immunodominant peptide from NY-ESO-1 (ESO), a tumor antigen frequently expressed in different human solid and hematologic cancers, to implement an in vitro priming platform allowing the generation of ESO-specific T(H) lines. We isolated phenotypically defined CD4(+) T-cell subpopulations from circulating lymphocytes of DR52b(+) healthy donors by flow cytometry cell sorting and stimulated them in vitro with peptide ESO(119-143), autologous APC and IL-2. We assessed the frequency of ESO-specific cells in the cultures by staining with DR52b/ESO(119-143) tetramers (ESO-tetramers) and TCR repertoire of ESO-tetramer(+) cells by co-staining with TCR variable β chain (BV) specific antibodies. We isolated ESO-tetramer(+) cells by flow cytometry cell sorting and expanded them with PHA, APC and IL-2 to generate ESO-specific T(H) lines. We characterized the lines for antigen recognition, by stimulation with ESO peptide or recombinant protein, cytokine production, by intracellular staining using specific antibodies, and alloreactivity, by stimulation with allo-APC. Using this approach, we could consistently generate ESO-tetramer(+) T(H) lines from conventional CD4(+)CD25(-) naïve and central memory populations, but not from effector memory populations or CD4(+)CD25(+) Treg. In vitro primed T(H) lines recognized ESO with affinities comparable to ESO-tetramer(+) cells from patients immunized with an ESO vaccine and used a similar TCR repertoire. In this study, using MHC class II/ESO tetramers, we have implemented an in vitro priming platform allowing the generation of ESO

  18. Interaction analysis between HLA-DRB1 shared epitope alleles and MHC class II transactivator CIITA gene with regard to risk of rheumatoid arthritis.

    Directory of Open Access Journals (Sweden)

    Marcus Ronninger

    Full Text Available HLA-DRB1 shared epitope (SE alleles are the strongest genetic determinants for autoantibody positive rheumatoid arthritis (RA. One of the key regulators in expression of HLA class II receptors is MHC class II transactivator (CIITA. A variant of the CIITA gene has been found to associate with inflammatory diseases.We wanted to explore whether the risk variant rs3087456 in the CIITA gene interacts with the HLA-DRB1 SE alleles regarding the risk of developing RA. We tested this hypothesis in a case-control study with 11767 individuals from four European Caucasian populations (6649 RA cases and 5118 controls.We found no significant additive interaction for risk alleles among Swedish Caucasians with RA (n = 3869, attributable proportion due to interaction (AP = 0.2, 95%CI: -0.2-0.5 or when stratifying for anti-citrullinated protein antibodies (ACPA presence (ACPA positive disease: n = 2945, AP = 0.3, 95%CI: -0.05-0.6, ACPA negative: n = 2268, AP = -0.2, 95%CI: -1.0-0.6. We further found no significant interaction between the main subgroups of SE alleles (DRB1*01, DRB1*04 or DRB1*10 and CIITA. Similar analysis of three independent RA cohorts from British, Dutch and Norwegian populations also indicated an absence of significant interaction between genetic variants in CIITA and SE alleles with regard to RA risk.Our data suggest that risk from the CIITA locus is independent of the major risk for RA from HLA-DRB1 SE alleles, given that no significant interaction between rs3087456 and SE alleles was observed. Since a biological link between products of these genes is evident, the genetic contribution from CIITA and class II antigens in the autoimmune process may involve additional unidentified factors.

  19. NetMHCcons: a consensus method for the major histocompatibility complex class I predictions

    DEFF Research Database (Denmark)

    Karosiene, Edita; Lundegaard, Claus; Lund, Ole;

    2012-01-01

    A key role in cell-mediated immunity is dedicated to the major histocompatibility complex (MHC) molecules that bind peptides for presentation on the cell surface. Several in silico methods capable of predicting peptide binding to MHC class I have been developed. The accuracy of these methods...... depends on the data available characterizing the binding specificity of the MHC molecules. It has, moreover, been demonstrated that consensus methods defined as combinations of two or more different methods led to improved prediction accuracy. This plethora of methods makes it very difficult for the non......-expert user to choose the most suitable method for predicting binding to a given MHC molecule. In this study, we have therefore made an in-depth analysis of combinations of three state-of-the-art MHC–peptide binding prediction methods (NetMHC, NetMHCpan and PickPocket). We demonstrate that a simple...

  20. The interaction between beta 2-microglobulin (beta 2m) and purified class-I major histocompatibility (MHC) antigen

    DEFF Research Database (Denmark)

    Pedersen, L O; Hansen, A S; Olsen, A C;

    1994-01-01

    been generated recently and this paper reports on a similar assay for the interaction between beta 2m and class I. As a model system human beta 2m binding to mouse class I was used. The assay is strictly biochemical using purified reagents which interact in solution and complex formation is determined...... by size separation. It is specific and highly sensitive. The observed affinity of the interaction, KD, is close to 0.4 nM. The rate of association at 37 degrees C is very fast (the ka is around 5 x 10(4)/M/s) whereas the dissociation is slow (the kd is around 8 x 10(-6)/s); the ratio of dissociation...

  1. Uncovering the Peptide-Binding Specificities of HLA-C: A General Strategy To Determine the Specificity of Any MHC Class I Molecule

    DEFF Research Database (Denmark)

    Rasmussen, Michael; Harndahl, Mikkel; Stryhn, Anette;

    2014-01-01

    library approach with a peptide-HLA-I dissociation assay, in this study we present a general strategy to determine the peptide-binding specificity of any MHC class I molecule. We applied this novel strategy to 17 of the most common HLA-C molecules, and for 16 of these we successfully generated matrices...... representing their peptide-binding motifs. The motifs prominently shared a conserved C-terminal primary anchor with hydrophobic amino acid residues, as well as one or more diverse primary and auxiliary anchors at P1, P2, P3, and/or P7. Matrices were used to generate a large panel of HLA-C-specific peptide...... molecules. Assessing the functional significance of these new tools, HLA-C*07:01 transgenic mice were immunized with stable HLA-C*07:01 binders; six of six tested stable peptide binders were immunogenic. Finally, we generated HLA-C tetramers and labeled human CD8(+) T cells and NK cells. These new resources...

  2. Invariant chain as a vehicle to load antigenic peptides on human MHC class I for cytotoxic T-cell activation.

    Science.gov (United States)

    Wälchli, Sébastien; Kumari, Shraddha; Fallang, Lars-Egil; Sand, Kine M K; Yang, Weiwen; Landsverk, Ole J B; Bakke, Oddmund; Olweus, Johanna; Gregers, Tone F

    2014-03-01

    Protective T-cell responses depend on efficient presentation of antigen (Ag) in the context of major histocompatibility complex class I (MHCI) and class II (MHCII) molecules. Invariant chain (Ii) serves as a chaperone for MHCII molecules and mediates trafficking to the endosomal pathway. The genetic exchange of the class II-associated Ii peptide (CLIP) with antigenic peptides has proven efficient for loading of MHCII and activation of specific CD4(+) T cells. Here, we investigated if Ii could similarly activate human CD8(+) T cells when used as a vehicle for cytotoxic T-cell (CTL) epitopes. The results show that wild type Ii, and Ii in which CLIP was replaced by known CTL epitopes from the cancer targets MART-1 or CD20, coprecipitated with HLA-A*02:01 and mediated colocalization in the endosomal pathway. Furthermore, HLA-A*02:01-positive cells expressing CLIP-replaced Ii efficiently activated Ag-specific CD8(+) T cells in a TAP- and proteasome-independent manner. Finally, dendritic cells transfected with mRNA encoding IiMART-1 or IiCD20 primed naïve CD8(+) T cells. The results show that Ii carrying antigenic peptides in the CLIP region can promote efficient presentation of the epitopes to CTLs independently of the classical MHCI peptide loading machinery, facilitating novel vaccination strategies against cancer.

  3. New chicken Rfp-Y haplotypes on the basis of MHC class II RFLP and MLC analyses

    DEFF Research Database (Denmark)

    Juul-Madsen, H R; Zoorob, R; Auffray, C;

    1997-01-01

    New chicken Rfp-Y haplotypes were determined by the use of restriction fragment length polymorphism (RFLP) and mixed lymphocyte culture (MLC) in four different chicken haplotypes, B15, B19, B21, B201. The RFLP polymorphism was mapped to the Rfp-Y system by the use of a subclone (18.1) which maps...... near a polymorphic lectin gene located in the Rfp-Y system and DNA from families with known segregation of the implicated RFLP polymorphism. For the first time it is shown that major histocompatibility complex class II genes in the Rfp-Y system have functional implications. Sequence information...

  4. An immunocytochemical study of pulpal responses to cavity preparation by laser ablation in rat molars by using antibodies to heat shock protein (Hsp) 25 and class II MHC antigen.

    Science.gov (United States)

    Suzuki, Takeshi; Nomura, Shuichi; Maeda, Takeyasu; Ohshima, Hayato

    2004-03-01

    Initial responses of odontoblasts and immunocompetent cells to cavity preparation by laser ablation were investigated in rat molars. In untreated control teeth, intense heat shock protein (Hsp) 25 immunoreactivity was found in the cell bodies of odontoblasts, whereas cells immunopositive for the class II major histocompatibility complex (MHC) antigen were predominantly located beneath the odontoblast layer in the dental pulp. Cavity preparation caused the destruction of the odontoblast layer and the shift of most class-II-MHC-positive cells from the pulp-dentin border toward the pulp core at the affected site. Twelve hours after cavity preparation, numerous class-II-MHC-positive cells appeared along the pulp-dentin border and extended their processes deep into the exposed dentinal tubules, but subsequently disappeared from the pulp-dentin border together with Hsp-25-immunopositive cells by 24 h after the operation. By 3-5 days postoperation, distinct abscess formation consisting of polymorphonuclear leukocytes was found in the dental pulp. The penetration of masses of oral bacteria was recognizable in the dentinal tubules beneath the prepared cavity. These findings indicate that cavity preparation by laser ablation induces remarkable inflammation by continuous bacterial infections via dentinal tubules in this experimental model, thereby delaying pulpal regeneration.

  5. Human B lymphoblastoid cells contain distinct patterns of cathepsin activity in endocytic compartments and regulate MHC class II transport in a cathepsin S-independent manner.

    Science.gov (United States)

    Lautwein, Alfred; Kraus, Marianne; Reich, Michael; Burster, Timo; Brandenburg, J; Overkleeft, Herman S; Schwarz, Gerold; Kammer, Winfried; Weber, Ekkehard; Kalbacher, Hubert; Nordheim, Alfred; Driessen, Christoph

    2004-05-01

    Endocytic proteolysis represents a major functional component of the major histocompatibility complex class II antigen-presentation machinery. Although transport and assembly of class II molecules in the endocytic compartment are well characterized, we lack information about the pattern of endocytic protease activity along this pathway. Here, we used chemical tools that visualize endocytic proteases in an activity-dependent manner in combination with subcellular fractionation to dissect the subcellular distribution of the major cathepsins (Cat) CatS, CatB, CatH, CatD, CatC, and CatZ as well as the asparagine-specific endoprotease (AEP) in human B-lymphoblastoid cells (BLC). Endocytic proteases were distributed in two distinct patterns: CatB and CatZ were most prominent in early and late endosomes but absent from lysosomes, and CatH, CatS, CatD, CatC, and AEP distributed between late endosomes and lysosomes, suggesting that CatB and CatZ might be involved in the initial proteolytic attack on a given antigen. The entire spectrum of protease activity colocalized with human leukocyte antigen-DM and the C-terminal and N-terminal processing of invariant chain (Ii) in late endosomes. CatS was active in all endocytic compartments. Surprisingly and in contrast with results from dendritic cells, inhibition of CatS activity by leucine-homophenylalanine-vinylsulfone-phenol prevented N-terminal processing of Ii but did not alter the subcellular trafficking or surface delivery of class II complexes, as deferred from pulse-chase analysis in combination with subcellular fractionation and biotinylation of cell-surface protein. Thus, BLC contain distinct activity patterns of proteases in endocytic compartments and regulate the intracellular transport and surface-delivery of class II in a CatS-independent manner. PMID:14966190

  6. Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California

    OpenAIRE

    Moreno-Santillán, Diana D.; Eileen A Lacey; Gendron, Diane; Ortega, Jorge

    2016-01-01

    The genes of the Major Histocompatibility Complex (MHC) play an important role in the vertebrate immune response and are among the most polymorphic genes known in vertebrates. In some marine mammals, MHC genes have been shown to be characterized by low levels of polymorphism compared to terrestrial taxa; this reduction in variation is often explained as a result of lower pathogen pressures in marine habitats. To determine if this same reduction in variation applies to the migratory population...

  7. Revisiting MHC genes in spondyloarthritis.

    Science.gov (United States)

    Breban, Maxime; Costantino, Félicie; André, Claudine; Chiocchia, Gilles; Garchon, Henri-Jean

    2015-06-01

    Spondyloarthritis (SpA) refers to a variety of inflammatory rheumatic disorders with strong heritability. Shared genetic predisposition, as shown by familial aggregation, is largely attributable to the major histocompatibility complex (MHC) locus, which was estimated to account for approximately half of the whole disease heritability. The first predisposing allele identified more than 40 years ago is HLA-B27, which is a major gene predisposing to all forms of SpA. However, despite intensive research, its pathogenesis remains uncertain. Other MHC alleles belonging to the class I and class II regions have been identified to exert additional effect. Candidate-gene approaches and genome-wide studies have recently allowed identification of several new loci residing outside of the MHC region that are involved in the predisposition to SpA. Interestingly, some of those new genes, such as ERAP1, ERAP2, and NPEPPS, code for aminopeptidases that are involved in MHC class I presentation and were shown to interact with HLA-B27. PMID:25903667

  8. Constitutive induction of intestinal Tc17 cells in the absence of hematopoietic cell-specific MHC class II expression.

    Science.gov (United States)

    Rubino, Stephen J; Geddes, Kaoru; Magalhaes, Joao G; Streutker, Catherine; Philpott, Dana J; Girardin, Stephen E

    2013-11-01

    The enteric pathogen Citrobacter rodentium induces a mucosal IL-17 response in CD4(+) T helper (Th17) cells that is dependent on the Nod-like receptors Nod1 and Nod2. Here, we sought to determine whether this early Th17 response required antigen presentation by major histocompatibility complex class II (MHCII) for full induction. At early phases of C. rodentium infection, we observed that the intestinal mucosal Th17 response was fully blunted in irradiated mice reconstituted with MHCII-deficient (MHCII(-/-) →WT) hematopoietic cells. Surprisingly, we also observed a substantial increase in the relative frequency of IL-17(+) CD8(+) CD4(-) TCR-β(+) cells (Tc17 cells) and FOXP3(+) CD8(+) CD4(-) TCR-β(+) cells in the lamina propria and intraepithelial lymphocyte compartment of MHCII(-/-) →WT mice compared with that in WT→WT counterparts. Moreover, MHCII(-/-) →WT mice displayed increased susceptibility, increased bacterial translocation to deeper organs, and more severe colonic histopathology after infection with C. rodentium. Finally, a similar phenotype was observed in mice deficient for CIITA, a transcriptional regulator of MHCII expression. Together, these results indicate that MHCII is required to mount early mucosal Th17 responses to an enteric pathogen, and that MHCII regulates the induction of atypical CD8(+) T-cell subsets, such as Tc17 cells and FOXP3(+) CD8(+) cells, in vivo. PMID:23881368

  9. Class I major histocompatibility proteins are an essential component of the simian virus 40 receptor.

    Science.gov (United States)

    Breau, W C; Atwood, W J; Norkin, L C

    1992-04-01

    The class I molecules encoded by the major histocompatibility complex (MHC) present endogenously synthesized antigenic peptide fragments to cytotoxic T lymphocytes. We show here that these proteins are an essential component of the cell surface receptor for simian virus 40 (SV40). First, SV40 binding to cells can be blocked by two monoclonal antibodies against class I human lymphocyte antigen (HLA) proteins but not by monoclonal antibodies specific for other cell surface proteins. Second, SV40 does not bind to cells of two different human lymphoblastoid cell lines which do not express surface class I MHC proteins because of genetic defects in the beta 2-microglobulin gene in one line and in the HLA complex in the other. Transfection of these cell lines with cloned genes for beta 2-microglobulin and HLA-B8, respectively, restored expression of their surface class I MHC proteins and resulted in concomitant SV40 binding. Finally, SV40 binds to purified HLA proteins in vitro and selectively binds to class I MHC proteins in a cell surface extract.

  10. Doxorubicin-conjugated bacteriophages carrying anti-MHC class I chain-related A for targeted cancer therapy in vitro

    Science.gov (United States)

    Phumyen, Achara; Jantasorn, Siriporn; Jumnainsong, Amonrat; Leelayuwat, Chanvit

    2014-01-01

    Background Cancer therapy by systemic administration of anticancer drugs, besides the effectiveness shown on cancer cells, demonstrated the side effects and cytotoxicity on normal cells. The targeted drug-carrying nanoparticles may decrease the required drug concentration at the site and the distribution of drugs to normal tissues. Overexpression of major histocompatibility complex class I chain–related A (MICA) in cancer is useful as a targeted molecule for the delivery of doxorubicin to MICA-expressing cell lines. Methods The application of 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide (EDC) chemistry was employed to conjugate the major coat protein of bacteriophages carrying anti-MICA and doxorubicin in a mildly acid condition. Doxorubicin (Dox) on phages was determined by double fluorescence of phage particles stained by M13-fluorescein isothiocyanate (FITC) and drug autofluorescence by flow cytometry. The ability of anti-MICA on phages to bind MICA after doxorubicin conjugation was evaluated by indirect enzyme-linked immunosorbent assay. One cervical cancer and four cholangiocarcinoma cell lines expressing MICA were used as models to evaluate targeting activity by cell cytotoxicity test. Results Flow cytometry and indirect enzyme-linked immunosorbent assay demonstrated that most of the phages (82%) could be conjugated with doxorubicin, and the Dox-carrying phage-displaying anti-MICA (Dox-phage) remained the binding activity against MICA. Dox-phage was more efficient than free drugs in killing all the cell lines tested. The half maximal inhibitory concentration (IC50) values of Dox-phage were lower than those of free drugs at approximately 1.6–6 times depending on MICA expressions and the cell lines tested. Conclusion Evidently, the application of 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide chemistry is effective to conjugate doxorubicin and major coat protein of bacteriophages without destroying binding activity of MICA antibodies. Dox

  11. Interferon-γ induces expression of MHC class II on intestinal epithelial cells and protects mice from colitis.

    Directory of Open Access Journals (Sweden)

    Christoph Thelemann

    Full Text Available Immune responses against intestinal microbiota contribute to the pathogenesis of inflammatory bowel diseases (IBD and involve CD4(+ T cells, which are activated by major histocompatibility complex class II (MHCII molecules on antigen-presenting cells (APCs. However, it is largely unexplored how inflammation-induced MHCII expression by intestinal epithelial cells (IEC affects CD4(+ T cell-mediated immunity or tolerance induction in vivo. Here, we investigated how epithelial MHCII expression is induced and how a deficiency in inducible epithelial MHCII expression alters susceptibility to colitis and the outcome of colon-specific immune responses. Colitis was induced in mice that lacked inducible expression of MHCII molecules on all nonhematopoietic cells, or specifically on IECs, by continuous infection with Helicobacter hepaticus and administration of interleukin (IL-10 receptor-blocking antibodies (anti-IL10R mAb. To assess the role of interferon (IFN-γ in inducing epithelial MHCII expression, the T cell adoptive transfer model of colitis was used. Abrogation of MHCII expression by nonhematopoietic cells or IECs induces colitis associated with increased colonic frequencies of innate immune cells and expression of proinflammatory cytokines. CD4(+ T-helper type (Th1 cells - but not group 3 innate lymphoid cells (ILCs or Th17 cells - are elevated, resulting in an unfavourably altered ratio between CD4(+ T cells and forkhead box P3 (FoxP3(+ regulatory T (Treg cells. IFN-γ produced mainly by CD4(+ T cells is required to upregulate MHCII expression by IECs. These results suggest that, in addition to its proinflammatory roles, IFN-γ exerts a critical anti-inflammatory function in the intestine which protects against colitis by inducing MHCII expression on IECs. This may explain the failure of anti-IFN-γ treatment to induce remission in IBD patients, despite the association of elevated IFN-γ and IBD.

  12. Activity-dependent regulation of MHC class I expression in the developing primary visual cortex of the common marmoset monkey

    Directory of Open Access Journals (Sweden)

    Schlumbohm Christina

    2011-01-01

    Full Text Available Abstract Background Several recent studies have highlighted the important role of immunity-related molecules in synaptic plasticity processes in the developing and adult mammalian brains. It has been suggested that neuronal MHCI (major histocompatibility complex class I genes play a role in the refinement and pruning of synapses in the developing visual system. As a fast evolutionary rate may generate distinct properties of molecules in different mammalian species, we studied the expression of MHCI molecules in a nonhuman primate, the common marmoset monkey (Callithrix jacchus. Methods and results Analysis of expression levels of MHCI molecules in the developing visual cortex of the common marmoset monkeys revealed a distinct spatio-temporal pattern. High levels of expression were detected very early in postnatal development, at a stage when synaptogenesis takes place and ocular dominance columns are formed. To determine whether the expression of MHCI molecules is regulated by retinal activity, animals were subjected to monocular enucleation. Levels of MHCI heavy chain subunit transcripts in the visual cortex were found to be elevated in response to monocular enucleation. Furthermore, MHCI heavy chain immunoreactivity revealed a banded pattern in layer IV of the visual cortex in enucleated animals, which was not observed in control animals. This pattern of immunoreactivity indicated that higher expression levels were associated with retinal activity coming from the intact eye. Conclusions These data demonstrate that, in the nonhuman primate brain, expression of MHCI molecules is regulated by neuronal activity. Moreover, this study extends previous findings by suggesting a role for neuronal MHCI molecules during synaptogenesis in the visual cortex.

  13. A family of nonclassical class I MHC genes contributes to ultrasensitive chemodetection by mouse vomeronasal sensory neurons.

    Science.gov (United States)

    Leinders-Zufall, Trese; Ishii, Tomohiro; Chamero, Pablo; Hendrix, Philipp; Oboti, Livio; Schmid, Andreas; Kircher, Sarah; Pyrski, Martina; Akiyoshi, Sachiko; Khan, Mona; Vaes, Evelien; Zufall, Frank; Mombaerts, Peter

    2014-04-01

    The mouse vomeronasal organ (VNO) has a pivotal role in chemical communication. The vomeronasal sensory neuroepithelium consists of distinct populations of vomeronasal sensory neurons (VSNs). A subset of VSNs, with cell bodies in the basal part of the basal layer, coexpress Vmn2r G-protein-coupled receptor genes with H2-Mv genes, a family of nine nonclassical class I major histocompatibility complex genes. The in vivo, physiological roles of the H2-Mv gene family remain mysterious more than a decade after the discovery of combinatorial H2-Mv gene expression in VSNs. Here, we have taken a genetic approach and have deleted the 530 kb cluster of H2-Mv genes in the mouse germline by chromosome engineering. Homozygous mutant mice (ΔH2Mv mice) are viable and fertile. There are no major anatomical defects in their VNO and accessory olfactory bulb (AOB). Their VSNs can be stimulated with chemostimuli (peptides and proteins) to the same maximum responses as VSNs of wild-type mice, but require much higher concentrations. This physiological phenotype is displayed at the single-cell level and is cell autonomous: single V2rf2-expressing VSNs, which normally coexpress H2-Mv genes, display a decreased sensitivity to a peptide ligand in ΔH2Mv mice, whereas single V2r1b-expressing VSNs, which do not coexpress H2-Mv genes, show normal sensitivity to a peptide ligand in ΔH2Mv mice. Consistent with the greatly decreased VSN sensitivity, ΔH2Mv mice display pronounced deficits in aggressive and sexual behaviors. Thus, H2-Mv genes are not absolutely essential for the generation of physiological responses, but are required for ultrasensitive chemodetection by a subset of VSNs. PMID:24719092

  14. Peptide-specific T helper cells identified by MHC class II tetramers differentiate into several subtypes upon immunization with CAF01 adjuvanted H56 tuberculosis vaccine formulation.

    Science.gov (United States)

    Prota, Gennaro; Christensen, Dennis; Andersen, Peter; Medaglini, Donata; Ciabattini, Annalisa

    2015-11-27

    CD4(+) T-cell priming is an essential step in vaccination due to the key role of T helper cells in driving both effector and memory immune responses. Here we have characterized in C57BL/6 mice the T helper subtype differentiation among tetramer-specific CD4(+) T cells primed by subcutaneous immunization with the tuberculosis vaccine antigen H56 plus the adjuvant CAF01. Peptide-specific population identified by the MHC class II tetramers differentiated into several T helper subtypes upon antigen encounter, and the frequency of subpopulations differed according to their localization. Th1 (CXCR3(+)T-bet(+)), Tfh (CXCR5(+)PD-1(+)Bcl-6(+)) and RORγt(+) cells were induced in the lymph nodes draining the immunization site (dLN), while Th1 cells were the predominant subtype in the spleen. In addition, CD4(+) T cells co-expressing multiple T-cell lineage-specifying transcription factors were also detected. In the lungs, most of the tetramer-binding T cells were RORγt(+), while Tfh and Th1 cells were absent. After boosting, a higher frequency of tetramer-binding cells co-expressing the markers CD44 and CD127 was detected compared to primed cells, and cells showed a prevalent Th1 phenotype in both dLN and spleens, while Tfh cells were significantly reduced. In conclusion, these data demonstrate that parenteral immunization with H56 and CAF01 elicits a distribution of antigen-specific CD4(+) T cells in both lymphoid tissues and lungs, and gives rise to multiple T helper subtypes, that differ depending on localization and following reactivation.

  15. Induction of antigen-presenting capacity in tumor cells upon infection with non-replicating recombinant vaccinia virus encoding murine MHC class II and costimulatory molecules.

    Science.gov (United States)

    Marti, W R; Oertli, D; Meko, J B; Norton, J A; Tsung, K

    1997-01-15

    The possibility of inducing antigen-presenting capacity in cells normally lacking such capacity, currently represents a major goal in vaccine research. To address this issue we attempted to generate 'artificial' APC able to stimulate CD4+ T cell responses when tumor cells were infected with a single, recombinant, vaccinia virus (rVV) containing the two genes encoding murine MHC class II I-Ak and a third gene encoding the murine B7-1 (mB7-1) costimulatory molecule. To minimize the cytopathic effect and to improve safety, in view of possible in vivo applications, we made this rVV replication incompetent by Psoralen and long wave UV treatment. Tumor cells infected with rVV encoding I-Ak alone, pulsed with hen egg white lysozyme peptide (HEL46-61), induced IL-2 secretion by an antigen-specific T hybridoma. Tumor cells infected with the rVV encoding mB7-1 provided costimulation for activating resting CD4+ T cells in the presence of ConA. Tumor cells infected with the rVV encoding I-Ak and mB7-1, and pulsed with chicken ovotransferrin peptide (conalbumin133-145), induced a significantly higher response in a specific Th2 cell clone (D10.G4.1) as compared to cells infected with rVV encoding I-Ak molecules only. Thus, this replication incompetent rVV represents a safe, multiple gene, vector system able to confer in one single infection step effective APC capacity to non-professional APCs.

  16. UL16-binding proteins, novel MHC class I-related proteins, bind to NKG2D and activate multiple signaling pathways in primary NK cells.

    Science.gov (United States)

    Sutherland, Claire L; Chalupny, N Jan; Schooley, Kenneth; VandenBos, Tim; Kubin, Marek; Cosman, David

    2002-01-15

    The UL16-binding proteins (ULBPs) are a novel family of MHC class I-related molecules that were identified as targets of the human CMV glycoprotein, UL16. We have previously shown that ULBP expression renders a relatively resistant target cell sensitive to NK cytotoxicity, presumably by engaging NKG2D, an activating receptor expressed by NK and other immune effector cells. In this study we show that NKG2D is the ULBP counterstructure on primary NK cells and that its expression is up-regulated by IL-15 stimulation. Soluble forms of ULBPs induce marked protein tyrosine phosphorylation, and activation of the Janus kinase 2, STAT5, extracellular signal-regulated kinase, mitogen-activated protein kinase, and phosphatidylinositol 3-kinase (PI 3-kinase)/Akt signal transduction pathways. ULBP-induced activation of Akt and extracellular signal-regulated kinase and ULBP-induced IFN-gamma production are blocked by inhibitors of PI 3-kinase, consistent with the known binding of PI 3-kinase to DAP10, the membrane-bound signal-transducing subunit of the NKG2D receptor. While all three ULBPs activate the same signaling pathways, ULBP3 was found to bind weakly and to induce the weakest signal. In summary, we have shown that NKG2D is the ULBP counterstructure on primary NK cells and for the first time have identified signaling pathways that are activated by NKG2D ligands. These results increase our understanding of the mechanisms by which NKG2D activates immune effector cells and may have implications for immune surveillance against pathogens and tumors. PMID:11777960

  17. Microsatellite allele A5.1 of MHC class I chain-related gene A is associated with latent autoimmune diabetes in adults in Latvia.

    Science.gov (United States)

    Berzina, L; Shtauvere-Brameus, A; Rumba, I; Sanjeevi, C B

    2002-04-01

    NIDDM is one of the most common forms of diabetes. The diagnosis is based on WHO classification, which is a clinical classification and misses the autoimmune diabetes in adults. Therefore, among the clinically diagnosed NIDDM cases, there can be a certain number of patients with latent autoimmune diabetes in adults (LADA). The MICA gene is located in the MHC class I region and is expressed by monocytes, keratinocytes, and endothelial cells. Sequence determination of the MICA gene identifies trinucleotide repeat (GCT) microsatellite polymorphism, which identifies 5 alleles with 4, 5, 6, and 9 repetitions of GCT (A4, A5, A6, and A9) or 5 repetitions of GCT with 1 additional G insertion for allele A5.1. From our previous studies, we have shown that microsatellite allele A5 of MICA is associated with IDDM. The aim of this study was to test the hypothesis that certain MICA alleles are associated with LADA among clinically diagnosed NIDDM. Out of 100 clinically diagnosed NIDDM patients, 49 tested positive for GAD65 and IA-2 antibodies by use of 35S RIA. Samples from these 49 patients and 96 healthy controls were analyzed for MICA by PCR amplification, and fragment sizes were determined in an ABI prism DNA sequencer. Our results show that MICA allele A5.1 is significantly increased in antibody-positive (GAD65 or IA-2) NIDDM patients [35/49 (72%)] when compared to healthy controls [22/96 (23%)] (OR = 8.4; P < 0.0001). However, we do not see any association with each of the antibodies separately. From our study, we conclude that (a) MICA allele A5.1 is associated with LADA and (b) MICA may play an important role in the etiopathogenesis of LADA.

  18. In vivo infiltration of mononuclear cells in squamous cell carcinoma of the head and neck correlates with the ability to expand tumour-infiltrating T cells in vitro and with the expression of MHC class I antigens on tumour cells

    DEFF Research Database (Denmark)

    Hald, J; Rasmussen, N; Claesson, Mogens Helweg

    1994-01-01

    A series of 18 head and neck squamous cell carcinoma biopsies, 6 primary and 12 recurrent, were investigated for tumour-infiltrating mononuclear cells with monoclonal or polyclonal antibodies. Our results suggest that the number of T cells at the tumour edge in vivo correlates well with their abi......A series of 18 head and neck squamous cell carcinoma biopsies, 6 primary and 12 recurrent, were investigated for tumour-infiltrating mononuclear cells with monoclonal or polyclonal antibodies. Our results suggest that the number of T cells at the tumour edge in vivo correlates well...... with their ability to expand in vitro in the presence of high-dose interleukin-2 (2000 U/ml). High MHC class I antigen expression on tumour cells was found to be positively correlated with p53 overexpression, suggesting that p53-derived peptides, wild-type or mutated ones, presented by MHC class I antigens......, are potential targets for MHC-restricted cytotoxic T cells in head and neck squamous cell carcinomas. However, lack of correlation between peritumoural T cell infiltration in vivo and T cell expansion in vitro, on the one hand, and p53 overexpression on tumour cells, on the other hand, suggests absence of p53...

  19. Antibody Stabilization of Peptide–MHC Multimers Reveals Functional T Cells Bearing Extremely Low-Affinity TCRs

    DEFF Research Database (Denmark)

    Tungatt, Katie; Bianchi, Valentina; Crowther, Michael D;

    2015-01-01

    Fluorochrome-conjugated peptide-MHC (pMHC) multimers are commonly used in combination with flow cytometry for direct ex vivo visualization and characterization of Ag-specific T cells, but these reagents can fail to stain cells when TCR affinity and/or TCR cell-surface density are low. pMHC multim...

  20. Innate lymphoid cells and the MHC.

    Science.gov (United States)

    Robinette, M L; Colonna, M

    2016-01-01

    Innate lymphoid cells (ILCs) are a new class of immune cells that include natural killer (NK) cells and appear to be the innate counterparts to CD4(+) helper T cells and CD8(+) cytotoxic T cells based on developmental and functional similarities. Like T cells, both NK cells and other ILCs also show connections to the major histocompatibility complex (MHC). In human and mouse, NK cells recognize and respond to classical and nonclassical MHC I molecules as well as structural homologues, whereas mouse ILCs have recently been shown to express MHC II. We describe the history of MHC I recognition by NK cells and discuss emerging roles for MHC II expression by ILC subsets, making comparisons between both mouse and human when possible.

  1. The most common Chinese rhesus macaque MHC class I molecule shares peptide binding repertoire with the HLA-B7 supertype

    DEFF Research Database (Denmark)

    Solomon, C.; Southwood, S.; Hoof, Ilka;

    2010-01-01

    Of the two rhesus macaque subspecies used for AIDS studies, the Simian immunodeficiency virus-infected Indian rhesus macaque (Macaca mulatta) is the most established model of HIV infection, providing both insight into pathogenesis and a system for testing novel vaccines. Despite the Chinese rhesus...... macaque potentially being a more relevant model for AIDS outcomes than the Indian rhesus macaque, the Chinese-origin rhesus macaques have not been well-characterized for their major histocompatibility complex (MHC) composition and function, reducing their greater utilization. In this study, we...... sequences identified were novel. From all MHC alleles detected, we prioritized Mamu-A1*02201 for functional characterization based on its higher frequency of expression. Upon the development of MHC/peptide binding assays and definition of its associated motif, we revealed that this allele shares peptide...

  2. Comparative genome analyses reveal distinct structure in the saltwater crocodile MHC.

    Directory of Open Access Journals (Sweden)

    Weerachai Jaratlerdsiri

    Full Text Available The major histocompatibility complex (MHC is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. The MHC is generally divided into subregions (classes I, II and III containing genes of similar function across species, but with different gene number and organisation. Crocodylia (crocodilians are widely distributed and represent an evolutionary distinct group among higher vertebrates, but the genomic organisation of MHC within this lineage has been largely unexplored. Here, we studied the MHC region of the saltwater crocodile (Crocodylus porosus and compared it with that of other taxa. We characterised genomic clusters encompassing MHC class I and class II genes in the saltwater crocodile based on sequencing of bacterial artificial chromosomes. Six gene clusters spanning ∼452 kb were identified to contain nine MHC class I genes, six MHC class II genes, three TAP genes, and a TRIM gene. These MHC class I and class II genes were in separate scaffold regions and were greater in length (2-6 times longer than their counterparts in well-studied fowl B loci, suggesting that the compaction of avian MHC occurred after the crocodilian-avian split. Comparative analyses between the saltwater crocodile MHC and that from the alligator and gharial showed large syntenic areas (>80% identity with similar gene order. Comparisons with other vertebrates showed that the saltwater crocodile had MHC class I genes located along with TAP, consistent with birds studied. Linkage between MHC class I and TRIM39 observed in the saltwater crocodile resembled MHC in eutherians compared, but absent in avian MHC, suggesting that the saltwater crocodile MHC appears to have gene organisation intermediate between these two lineages. These observations suggest that the structure of the saltwater crocodile MHC, and other crocodilians, can help determine the MHC that was present in the ancestors of archosaurs.

  3. Characterization of MHC class II B polymorphism in multiple populations of wild gorillas using non-invasive samples and next-generation sequencing.

    Science.gov (United States)

    Hans, Jörg B; Haubner, Anne; Arandjelovic, Mimi; Bergl, Richard A; Fünfstück, Tillmann; Gray, Maryke; Morgan, David B; Robbins, Martha M; Sanz, Crickette; Vigilant, Linda

    2015-11-01

    Genes encoded by the major histocompatibility complex (MHC) are crucial for the recognition and presentation of antigens to the immune system. In contrast to their closest relatives, chimpanzees and humans, much less is known about variation in gorillas at these loci. This study explored the exon 2 variation of -DPB1, -DQB1, and -DRB genes in 46 gorillas from four populations while simultaneously evaluating the feasibility of using fecal samples for high-throughput MHC genotyping. By applying strict similarity- and frequency-based analysis, we found, despite our modest sample size, a total of 18 alleles that have not been described previously, thereby illustrating the potential for efficient and highly accurate MHC genotyping from non-invasive DNA samples. We emphasize the importance of controlling for multiple potential sources of error when applying this massively parallel short-read sequencing technology to PCR products generated from low concentration DNA extracts. We observed pronounced differences in MHC variation between species, subspecies and populations that are consistent with both the ancient and recent demographic histories experienced by gorillas.

  4. Towards the MHC-peptide combinatorics.

    Science.gov (United States)

    Kangueane, P; Sakharkar, M K; Kolatkar, P R; Ren, E C

    2001-05-01

    The exponentially increased sequence information on major histocompatibility complex (MHC) alleles points to the existence of a high degree of polymorphism within them. To understand the functional consequences of MHC alleles, 36 nonredundant MHC-peptide complexes in the protein data bank (PDB) were examined. Induced fit molecular recognition patterns such as those in MHC-peptide complexes are governed by numerous rules. The 36 complexes were clustered into 19 subgroups based on allele specificity and peptide length. The subgroups were further analyzed for identifying common features in MHC-peptide binding pattern. The four major observations made during the investigation were: (1) the positional preference of peptide residues defined by percentage burial upon complex formation is shown for all the 19 subgroups and the burial profiles within entries in a given subgroup are found to be similar; (2) in class I specific 8- and 9-mer peptides, the fourth residue is consistently solvent exposed, however this observation is not consistent in class I specific 10-mer peptides; (3) an anchor-shift in positional preference is observed towards the C terminal as the peptide length increases in class II specific peptides; and (4) peptide backbone atoms are proportionately dominant at the MHC-peptide interface.

  5. From Sanger to NGS: Detecting MHC (Major Histocompatibility Complex) Class II and OR (Olfactory Receptors) Genetic Variability in Italian Wolves (Canis Lupus) and relative Canids

    OpenAIRE

    Lapalombella, Silvana

    2016-01-01

    In this PhD thesis I will describe different aspects of conservation genetics and genomics of two wild Canidae species, the wolf (Canis lupus) and the golden jackal (Canis aureus), through the study of two of the most variable gene families: the Major Histocompatibility Complex genes (MHC), and Olfactory Receptors genes (OR). In order to perform these studies both Sanger and next generation sequencing (NGS) DNA techniques have been used. The background of the thesis is described in the “Gener...

  6. Comparative sequencing of human and chimpanzee MHC class I regions unveils insertions/deletions as the major path to genomic divergence

    OpenAIRE

    Anzai, Tatsuya; Shiina, Takashi; Kimura, Natsuki; Yanagiya, Kazuyo; Kohara, Sakae; Shigenari, Atsuko; Yamagata, Tetsushi; Kulski, Jerzy K.; Naruse, Taeko K.; Fujimori, Yoshifumi; Fukuzumi, Yasuhito; Yamazaki, Masaaki; Tashiro, Hiroyuki; Iwamoto, Chie; Umehara, Yumi

    2003-01-01

    Despite their high degree of genomic similarity, reminiscent of their relatively recent separation from each other (≈6 million years ago), the molecular basis of traits unique to humans vs. their closest relative, the chimpanzee, is largely unknown. This report describes a large-scale single-contig comparison between human and chimpanzee genomes via the sequence analysis of almost one-half of the immunologically critical MHC. This 1,750,601-bp stretch of DNA, which encompasses the entir...

  7. Major Histocompatibility Complex (MHC) Class I Processing of the NY-ESO-1 Antigen Is Regulated by Rpn10 and Rpn13 Proteins and Immunoproteasomes following Non-lysine Ubiquitination.

    Science.gov (United States)

    Golnik, Richard; Lehmann, Andrea; Kloetzel, Peter-Michael; Ebstein, Frédéric

    2016-04-15

    The supply of MHC class I-restricted peptides is primarily ensured by the degradation of intracellular proteins via the ubiquitin-proteasome system. Depending on the target and the enzymes involved, ubiquitination is a process that may dramatically vary in terms of linkages, length, and attachment sites. Here we identified the unique lysine residue at position 124 of the NY-ESO-1 cancer/testis antigen as the acceptor site for the formation of canonical Lys-48-linkages. Interestingly, a lysine-less form of NY-ESO-1 was as efficient as its wild-type counterpart in supplying the HLA-A*0201-restricted NY-ESO-1157-165 antigenic peptide. In fact, we show that the regulation of NY-ESO-1 processing by the ubiquitin receptors Rpn10 and Rpn13 as a well as by the standard and immunoproteasome is governed by non-canonical ubiquitination on non-lysine sites. In summary, our data underscore the significance of atypical ubiquitination in the modulation of MHC class I antigen processing.

  8. MHC motif viewer

    DEFF Research Database (Denmark)

    Rapin, Nicolas Philippe Jean-Pierre; Hoof, Ilka; Lund, Ole;

    2008-01-01

    In vertebrates, the major histocompatibility complex (MHC) presents peptides to the immune system. In humans, MHCs are called human leukocyte antigens (HLAs), and some of the loci encoding them are the most polymorphic in the human genome. Different MHC molecules present different subsets of....... Algorithms that predict which peptides MHC molecules bind have recently been developed and cover many different alleles, but the utility of these algorithms is hampered by the lack of tools for browsing and comparing the specificity of these molecules. We have, therefore, developed a web server, MHC motif...

  9. The MHC motif viewer

    DEFF Research Database (Denmark)

    Rapin, Nicolas Philippe Jean-Pierre; Hoof, Ilka; Lund, Ole;

    2010-01-01

    In vertebrates, the onset of cellular immune reactions is controlled by presentation of peptides in complex with major histocompatibility complex (MHC) molecules to T cell receptors. In humans, MHCs are called human leukocyte antigens (HLAs). Different MHC molecules present different subsets of...... peptides, and knowledge of their binding specificities is important for understanding differences in the immune response between individuals. Algorithms predicting which peptides bind a given MHC molecule have recently been developed with high prediction accuracy. The utility of these algorithms is...... binding motif for each MHC molecule is predicted using state-of-the-art, pan-specific peptide-MHC binding-prediction methods, and is visualized as a sequence logo, in a format that allows for a comprehensive interpretation of binding motif anchor positions and amino acid preferences....

  10. Binding of human beta 2-microglobulin to murine EL4 thymoma cells upregulates MHC class I heavy-chain epitopes, inhibits IL-2 secretion and induces resistance to killing by natural killer cells

    DEFF Research Database (Denmark)

    Claësson, M H; Nissen, Mogens Holst

    1994-01-01

    . EL4 cells which had bound h beta 2m decreased their rate of constitutive IL-2 secretion and became resistant to activated natural killer (NK) cell killing. The present data suggest the binding of h beta 2m to mouse T cells leads to conformational changes of MHC-I heavy chains which influence both......A variety of murine tumor cell lines was studied for its binding of exogeneously added human beta 2-microglobulin (h beta 2m). Three T lymphomas and one IL-2-dependent T-cell line (HT-1) bound substantial amounts of h beta 2m, whereas P815 mastocytoma cells, an Abelson virus-infected pre-B cell...... line (ABLS-8), X63 B-lymphoma cells and YAC cells did not bind h beta 2m. In two of the T lymphomas, EL4 and BW5147, binding of h beta 2m led to an increase in major histocompatibility complex class I (MHC-I) heavy-chain epitope expression as measured by anti-H-2K/D antibody binding and FACS analysis...

  11. Cancer cells become susceptible to natural killer cell killing after exposure to histone deacetylase inhibitors due to glycogen synthase kinase-3-dependent expression of MHC class I-related chain A and B

    DEFF Research Database (Denmark)

    Skov, Søren; Pedersen, Marianne Terndrup; Andresen, Lars;

    2005-01-01

    We show that histone deacetylase (HDAC) inhibitors lead to functional expression of MHC class I-related chain A and B (MICA/B) on cancer cells, making them potent targets for natural killer (NK) cell-mediated killing through a NK group 2, member D (NKG2D) restricted mechanism. Blocking either...... apoptosis or oxidative stress caused by HDAC inhibitor treatment did not affect MICA/B expression, suggesting involvement of a separate signal pathway not directly coupled to induction of cell death. HDAC inhibitor treatment induced glycogen synthase kinase-3 (GSK-3) activity and down-regulation of GSK-3...... by small interfering RNA or by different inhibitors showed that GSK-3 activity is essential for the induced MICA/B expression. We thus present evidence that cancer cells which survive the direct induction of cell death by HDAC inhibitors become targets for NKG2D-expressing cells like NK cells, gammadelta T...

  12. DNA Vaccines Encoding Antigen Targeted to MHC Class II Induce Influenza-Specific CD8(+) T Cell Responses, Enabling Faster Resolution of Influenza Disease.

    Science.gov (United States)

    Lambert, Laura; Kinnear, Ekaterina; McDonald, Jacqueline U; Grodeland, Gunnveig; Bogen, Bjarne; Stubsrud, Elisabeth; Lindeberg, Mona M; Fredriksen, Agnete Brunsvik; Tregoning, John S

    2016-01-01

    Current influenza vaccines are effective but imperfect, failing to cover against emerging strains of virus and requiring seasonal administration to protect against new strains. A key step to improving influenza vaccines is to improve our understanding of vaccine-induced protection. While it is clear that antibodies play a protective role, vaccine-induced CD8(+) T cells can improve protection. To further explore the role of CD8(+) T cells, we used a DNA vaccine that encodes antigen dimerized to an immune cell targeting module. Immunizing CB6F1 mice with the DNA vaccine in a heterologous prime-boost regime with the seasonal protein vaccine improved the resolution of influenza disease compared with protein alone. This improved disease resolution was dependent on CD8(+) T cells. However, DNA vaccine regimes that induced CD8(+) T cells alone were not protective and did not boost the protection provided by protein. The MHC-targeting module used was an anti-I-E(d) single chain antibody specific to the BALB/c strain of mice. To test the role of MHC targeting, we compared the response between BALB/c, C57BL/6 mice, and an F1 cross of the two strains (CB6F1). BALB/c mice were protected, C57BL/6 were not, and the F1 had an intermediate phenotype; showing that the targeting of antigen is important in the response. Based on these findings, and in agreement with other studies using different vaccines, we conclude that, in addition to antibody, inducing a protective CD8 response is important in future influenza vaccines. PMID:27602032

  13. Genetic Diversity and mRNA Expression of Porcine MHC Class I Chain-Related 2 (SLA-MIC2) Gene and Development of a High-Resolution Typing Method.

    Science.gov (United States)

    Dadi, Hailu; Le, MinhThong; Dinka, Hunduma; Nguyen, DinhTruong; Choi, Hojun; Cho, Hyesun; Choi, Minkyeung; Kim, Jin-Hoi; Park, Jin-Ki; Soundrarajan, Nagasundarapandian; Park, Chankyu

    2015-01-01

    The genetic structure and function of MHC class I chain-related (MIC) genes in the pig genome have not been well characterized, and show discordance in available data. Therefore, we have experimentally characterized the exon-intron structure and functional copy expression pattern of the pig MIC gene, SLA-MIC2. We have also studied the genetic diversity of SLA-MIC2 from seven different breeds using a high-resolution genomic sequence-based typing (GSBT) method. Our results showed that the SLA-MIC2 gene has a similar molecular organization as the human and cattle orthologs, and is expressed in only a few tissues including the small intestine, lung, and heart. A total of fifteen SLA-MIC2 alleles were identified from typing 145 animals, ten of which were previously unreported. Our analysis showed that the previously reported and tentatively named SLA-MIC2*05, 07, and 01 alleles occurred most frequently. The observed heterozygosity varied from 0.26 to 0.73 among breeds. The number of alleles of the SLA-MIC2 gene in pigs is somewhat lower compared to the number of alleles of the porcine MHC class I and II genes; however, the level of heterozygosity was similar. Our results indicate the comprehensiveness of using genomic DNA-based typing for the systemic study of the SLA-MIC2 gene. The method developed for this study, as well as the detailed information that was obtained, could serve as fundamental tools for understanding the influence of the SLA-MIC2 gene on porcine immune responses.

  14. Distribution of class ii major histocompatibility complex antigenexpressing cells in human dental pulp with carious lesions

    Directory of Open Access Journals (Sweden)

    Tetiana Haniastuti

    2012-09-01

    Full Text Available Background: Dental caries is a bacterial infection which causes destruction of the hard tissues of the tooth. Exposure of the dentin to the oral environment as a result of caries inevitably results in a cellular response in the pulp. The major histocompatibility complex (MHC is a group of genes that code for cell-surface histocompatibility antigens. Cells expressing class II MHC molecules participate in the initial recognition and the processing of antigenic substances to serve as antigen-presenting cells. Purpose: The aim of the study was to elucidate the alteration in the distribution of class II MHC antigen-expressing cells in human dental pulp as carious lesions progressed toward the pulp. Methods: Fifteen third molars with caries at the occlusal site at various stages of decay and 5 intact third molars were extracted and used in this study. Before decalcifying with 10% EDTA solution (pH 7.4, all the samples were observed by micro-computed tomography to confirm the lesion condition three-dimensionally. The specimens were then processed for cryosection and immunohistochemistry using an anti-MHC class II monoclonal antibody. Results: Class II MHC antigen-expressing cells were found both in normal and carious specimens. In normal tooth, the class II MHC-immunopositive cells were observed mainly at the periphery of the pulp tissue. In teeth with caries, class II MHC-immunopositive cells were located predominantly subjacent to the carious lesions. As the caries progressed, the number of class II MHC antigen-expressing cells was increased. Conclusion: The depth of carious lesions affects the distribution of class II MHC antigen-expressing cells in the dental pulp.Latar belakang: Karies merupakan penyakit infeksi bakteri yang mengakibatkan destruksi jaringan keras gigi. Dentin yang terbuka akibat karies akan menginduksi respon imun seluler pada pulpa. Kompleks histokompatibilitas utama (MHC merupakan sekumpulan gen yang mengkode histokompatibilitas

  15. MHC-Dependent Desensitization of Intrinsic Anti-Self Reactivity

    OpenAIRE

    Jubala, Cristan M.; Lamerato-Kozicki, Angela R.; Borakove, Michelle; Lang, Julie; Gardner, Lori A.; Coffey, David; Helm, Karen M.; Schaack, Jerome; Baier, Monika; Cutter, Gary R.; Bellgrau, Donald; Modiano, Jaime F

    2008-01-01

    The survival of naïve T cells is compromised in the absence of molecules encoded by the major histocompatibility complex (MHC) while antigen-experienced T cells survive. We hypothesized that survival pressures in an in vivo, MHC-deficient environment would permit enrichment of less frequent antigen-experienced autoreactive cells at the expense of the majority of antigen naïve T cells. To test this hypothesis, we generated MHC class I and class II-deficient mice in NOD and C57Bl/6 (B6) backgro...

  16. Endoplasmic reticulum aminopeptidase 1 function and its pathogenic role in regulating innate and adaptive immunity in cancer and major histocompatibility complex class I-associated autoimmune diseases.

    Science.gov (United States)

    Fruci, D; Romania, P; D'Alicandro, V; Locatelli, F

    2014-08-01

    Major histocompatibility complex (MHC) class I molecules present antigenic peptides on the cell surface to alert natural killer (NK) cells and CD8(+) T cells for the presence of abnormal intracellular events, such as virus infection or malignant transformation. The generation of antigenic peptides is a multistep process that ends with the trimming of N-terminal extensions in the endoplasmic reticulum (ER) by aminopeptidases ERAP1 and ERAP2. Recent studies have highlighted the potential role of ERAP1 in reprogramming the immunogenicity of tumor cells in order to elicit innate and adaptive antitumor immune responses, and in conferring susceptibility to autoimmune diseases in predisposed individuals. In this review, we will provide an overview of the current knowledge about the role of ERAP1 in MHC class I antigen processing and how its manipulation may constitute a promising tool for cancer immunotherapy and treatment of MHC class I-associated autoimmune diseases. PMID:25066018

  17. Progress in the Polymorphism of Ovine MHC Class Ⅱ Gene%绵羊MHCⅡ类基因遗传多态性研究进展

    Institute of Scientific and Technical Information of China (English)

    惠文巧; 侯宏艳; 汤继顺; 朱德建; 班谦; 陈胜

    2015-01-01

    主要组织相容性复合体(major histocompatibility complex,MHC)是广泛存在于脊椎动物体内的一类高度紧密连锁的基因群,绵羊MHC又称为绵羊淋巴细胞表面抗原(ovine lymphocyte antigen,OLA),位于绵羊20号染色体上,分为Ⅰ类、Ⅱ类和Ⅲ类区域,其中MHCⅡ类基因具有高度的基因多态性.文章综述了绵羊MHCⅡ类基因的分子结构及遗传多态性,重点总结了近十年来国内外不同绵羊品种MHCⅡ类基因遗传多态性的研究进展,并对绵羊MHCⅡ类基因未来的研究重点进行了展望.

  18. A Lipid Based Antigen Delivery System Efficiently Facilitates MHC Class-I Antigen Presentation in Dendritic Cells to Stimulate CD8+ T Cells

    Science.gov (United States)

    Maji, Mithun; Mazumder, Saumyabrata; Bhattacharya, Souparno; Choudhury, Somsubhra Thakur; Sabur, Abdus; Shadab, Md.; Bhattacharya, Pradyot; Ali, Nahid

    2016-06-01

    The most effective strategy for protection against intracellular infections such as Leishmania is vaccination with live parasites. Use of recombinant proteins avoids the risks associated with live vaccines. However, due to low immunogenicity, they fail to trigger T cell responses particularly of CD8+ cells requisite for persistent immunity. Previously we showed the importance of protein entrapment in cationic liposomes and MPL as adjuvant for elicitation of CD4+ and CD8+ T cell responses for long-term protection. In this study we investigated the role of cationic liposomes on maturation and antigen presentation capacity of dendritic cells (DCs). We observed that cationic liposomes were taken up very efficiently by DCs and transported to different cellular sites. DCs activated with liposomal rgp63 led to efficient presentation of antigen to specific CD4+ and CD8+ T cells. Furthermore, lymphoid CD8+ T cells from liposomal rgp63 immunized mice demonstrated better proliferative ability when co-cultured ex vivo with stimulated DCs. Addition of MPL to vaccine enhanced the antigen presentation by DCs and induced more efficient antigen specific CD8+ T cell responses when compared to free and liposomal antigen. These liposomal formulations presented to CD8+ T cells through TAP-dependent MHC-I pathway offer new possibilities for a safe subunit vaccine.

  19. Peptide-loaded dendritic cells prime and activate MHC-class I-restricted T cells more efficiently than protein-loaded cross-presenting DC

    DEFF Research Database (Denmark)

    Met, Ozcan; Buus, Søren; Claesson, Mogens H

    2003-01-01

    Undifferentiated and differentiated dendritic cells (uDC and dDC, respectively), derived from the bone marrow, were studied in vitro and in vivo. Ovalbumin (OVA) and two OVA-derived peptides binding to H-2K(b) and I-A(b), respectively, were used. Two IL-2 secreting T cell hybridomas specific...... for the OVA-derived epitopes were used in the in vitro read-out. The ability to cross-present the H-2K(b) binding OVA(257-264)-peptide (SIINFEKL) was restricted to dDC, which express CD11c(+), CD86(+), and MHC-II(+). In vitro, the antigenicity of SIINFEKL-loaded DC declined at a slower rate than that of OVA......-pulsed DC. Moreover, SIINFEKL-loaded DC were up to 50 times more efficient than DC-pulsed with OVA-protein for generation of an H-2K(b)-restricted response. Immunization of mice with SIINFEKL-loaded DC resulted in a much stronger H-2K(b)-restricted response than immunization with OVA-pulsed DC. These data...

  20. Structural Basis of the CD8[alpha beta]/MHC Class I Interaction: Focused Recognition Orients CD8[beta] to a T Cell Proximal Position[superscript 1,2

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui; Natarajan, Kannan; Margulies, David H.; (NIH)

    2009-09-18

    In the immune system, B cells, dendritic cells, NK cells, and T lymphocytes all respond to signals received via ligand binding to receptors and coreceptors. Although the specificity of T cell recognition is determined by the interaction of T cell receptors with MHC/peptide complexes, the development of T cells in the thymus and their sensitivity to Ag are also dependent on coreceptor molecules CD8 (for MHC class I (MHCI)) and CD4 (for MHCII). The CD8{alpha}{beta} heterodimer is a potent coreceptor for T cell activation, but efforts to understand its function fully have been hampered by ignorance of the structural details of its interactions with MHCI. In this study we describe the structure of CD8{alpha}{beta} in complex with the murine MHCI molecule H-2D{sup d} at 2.6 {angstrom} resolution. The focus of the CD8{alpha}{beta} interaction is the acidic loop (residues 222-228) of the {alpha}3 domain of H-2D{sup d}. The {beta} subunit occupies a T cell membrane proximal position, defining the relative positions of the CD8{alpha} and CD8{beta} subunits. Unlike the CD8{alpha}{alpha} homodimer, CD8{alpha}{beta} does not contact the MHCI {alpha}{sub 2}- or {beta}{sub 2}-microglobulin domains. Movements of the CD8{alpha} CDR2 and CD8{beta} CDR1 and CDR2 loops as well as the flexibility of the H-2D{sup d} CD loop facilitate the monovalent interaction. The structure resolves inconclusive data on the topology of the CD8{alpha}{beta}/MHCI interaction, indicates that CD8{beta} is crucial in orienting the CD8{alpha}{beta} heterodimer, provides a framework for understanding the mechanistic role of CD8{alpha}{beta} in lymphoid cell signaling, and offers a tangible context for design of structurally altered coreceptors for tumor and viral immunotherapy.

  1. Differences in meiotic recombination rates in childhood acute lymphoblastic leukemia at an MHC class II hotspot close to disease associated haplotypes.

    Directory of Open Access Journals (Sweden)

    Pamela Thompson

    Full Text Available Childhood Acute Lymphoblastic Leukemia (ALL is a malignant lymphoid disease of which B-cell precursor- (BCP and T-cell- (T ALL are subtypes. The role of alleles encoded by major histocompatibility loci (MHC have been examined in a number of previous studies and results indicating weak, multi-allele associations between the HLA-DPB1 locus and BCP-ALL suggested a role for immunosusceptibility and possibly infection. Two independent SNP association studies of ALL identified loci approximately 37 kb from one another and flanking a strong meiotic recombination hotspot (DNA3, adjacent to HLA-DOA and centromeric of HLA-DPB1. To determine the relationship between this observation and HLA-DPB1 associations, we constructed high density SNP haplotypes of the 316 kb region from HLA-DMB to COL11A2 in childhood ALL and controls using a UK GWAS data subset and the software PHASE. Of four haplotype blocks identified, predicted haplotypes in Block 1 (centromeric of DNA3 differed significantly between BCP-ALL and controls (P = 0.002 and in Block 4 (including HLA-DPB1 between T-ALL and controls (P = 0.049. Of specific common (>5% haplotypes in Block 1, two were less frequent in BCP-ALL, and in Block 4 a single haplotype was more frequent in T-ALL, compared to controls. Unexpectedly, we also observed apparent differences in ancestral meiotic recombination rates at DNA3, with BCP-ALL showing increased and T-ALL decreased levels compared to controls. In silico analysis using LDsplit sotware indicated that recombination rates at DNA3 are influenced by flanking loci, including SNPs identified in childhood ALL association studies. The observed differences in rates of meiotic recombination at this hotspot, and potentially others, may be a characteristic of childhood leukemia and contribute to disease susceptibility, alternatively they may reflect interactions between ALL-associated haplotypes in this region.

  2. Structure of a pheromone receptor-associated MHC molecule with an open and empty groove.

    Directory of Open Access Journals (Sweden)

    Rich Olson

    2005-08-01

    Full Text Available Neurons in the murine vomeronasal organ (VNO express a family of class Ib major histocompatibility complex (MHC proteins (M10s that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide-binding MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I-binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8-10-mer class I-binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC-binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs.

  3. Structure of a Pheromone Receptor-Associated Mhc Molecule With An Open And Empty Groove

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.; Huey-Tubman, K.E.; Dulac, C.; Bjorkman, P.J.; /Caltech /Harvard U.

    2006-10-06

    Neurons in the murine vomeronasal organ (VNO) express a family of class Ib major histocompatibility complex (MHC) proteins (M10s) that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide-binding MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I-binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8-10-mer class I-binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC-binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs.

  4. MHC-Dependent Desensitization of Intrinsic Anti-Self Reactivity

    Science.gov (United States)

    Jubala, Cristan M.; Lamerato-Kozicki, Angela R.; Borakove, Michelle; Lang, Julie; Gardner, Lori A.; Coffey, David; Helm, Karen M.; Schaack, Jerome; Baier, Monika; Cutter, Gary R.; Bellgrau, Donald; Modiano, Jaime F.

    2008-01-01

    The survival of naïve T cells is compromised in the absence of molecules encoded by the major histocompatibility complex (MHC) while antigen-experienced T cells survive. We hypothesized that survival pressures in an in vivo, MHC-deficient environment would permit enrichment of less frequent antigen-experienced autoreactive cells at the expense of the majority of antigen naïve T cells. To test this hypothesis, we generated MHC class I and class II-deficient mice in NOD and C57Bl/6 (B6) backgrounds, and examined the capacity of adoptively transferred autoimmune-prone NOD T cells, or non-autoimmune prone naïve B6 T cells, respectively, to reject transplanted wild type pancreatic islets or transplantable tumors in the MHC-deficient mice. In the MHC-deficient environment, CD4 T cells acquired self-hostile properties (islet rejection and tumor invasion) that were independent from their genetic propensity for autoreactivity, while CD8 T cells required appropriate prior exposure to antigen in order to survive and function (reject tumor) in this environment; however, disengagement of Tob1, a negative regulator of proliferation, led to a reverse phenotype with regard to persistence of CD4 and CD8 T cells in the MHC-deficient environment. Our data suggest that self-peptide/MHC interactions have dual roles to facilitate survival and restrain autoreactivity, thus acting as integral components of an intrinsic network of negative regulation that maintains tolerance. PMID:18523772

  5. The Length Distribution of Class I-Restricted T Cell Epitopes Is Determined by Both Peptide Supply and MHC Allele-Specific Binding Preference

    DEFF Research Database (Denmark)

    Trolle, Thomas; McMurtrey, Curtis P.; Sidney, John;

    2016-01-01

    HLA class I-binding predictions are widely used to identify candidate peptide targets of human CD8+ T cell responses. Many such approaches focus exclusively on a limited range of peptide lengths, typically 9 aa and sometimes 9-10 aa, despite multiple examples of dominant epitopes of other lengths...

  6. Enhanced and sustained CD8+ T cell responses with an adenoviral vector-based hepatitis C virus vaccine encoding NS3 linked to the MHC class II chaperone protein invariant chain

    DEFF Research Database (Denmark)

    Mikkelsen, Marianne; Holst, Peter Johannes; Bukh, Jens;

    2011-01-01

    Potent and broad cellular immune responses against the nonstructural (NS) proteins of hepatitis C virus (HCV) are associated with spontaneous viral clearance. In this study, we have improved the immunogenicity of an adenovirus (Ad)-based HCV vaccine by fusing NS3 from HCV (Strain J4; Genotype 1b...... memory. Functionally, the AdIiNS3-vaccinated mice had a significantly increased cytotoxic capacity compared with the AdNS3 group. The AdIiNS3-induced CD8(+) T cells protected mice from infection with recombinant vaccinia virus expressing HCV NS3 of heterologous 1b strains, and studies in knockout mice......) to the MHC class II chaperone protein invariant chain (Ii). We found that, after a single vaccination of C57BL/6 or BALB/c mice with Ad-IiNS3, the HCV NS3-specific CD8(+) T cell responses were significantly enhanced, accelerated, and prolonged compared with the vaccine encoding NS3 alone. The AdIiNS3...

  7. MHCcluster, a method for functional clustering of MHC molecules.

    Science.gov (United States)

    Thomsen, Martin; Lundegaard, Claus; Buus, Søren; Lund, Ole; Nielsen, Morten

    2013-09-01

    The identification of peptides binding to major histocompatibility complexes (MHC) is a critical step in the understanding of T cell immune responses. The human MHC genomic region (HLA) is extremely polymorphic comprising several thousand alleles, many encoding a distinct molecule. The potentially unique specificities remain experimentally uncharacterized for the vast majority of HLA molecules. Likewise, for nonhuman species, only a minor fraction of the known MHC molecules have been characterized. Here, we describe a tool, MHCcluster, to functionally cluster MHC molecules based on their predicted binding specificity. The method has a flexible web interface that allows the user to include any MHC of interest in the analysis. The output consists of a static heat map and graphical tree-based visualizations of the functional relationship between MHC variants and a dynamic TreeViewer interface where both the functional relationship and the individual binding specificities of MHC molecules are visualized. We demonstrate that conventional sequence-based clustering will fail to identify the functional relationship between molecules, when applied to MHC system, and only through the use of the predicted binding specificity can a correct clustering be found. Clustering of prevalent HLA-A and HLA-B alleles using MHCcluster confirms the presence of 12 major specificity groups (supertypes) some however with highly divergent specificities. Importantly, some HLA molecules are shown not to fit any supertype classification. Also, we use MHCcluster to show that chimpanzee MHC class I molecules have a reduced functional diversity compared to that of HLA class I molecules. MHCcluster is available at www.cbs.dtu.dk/services/MHCcluster-2.0. PMID:23775223

  8. Interaction of TAPBPR, a tapasin homolog, with MHC-I molecules promotes peptide editing

    Science.gov (United States)

    Morozov, Giora I.; Zhao, Huaying; Mage, Michael G.; Boyd, Lisa F.; Jiang, Jiansheng; Dolan, Michael A.; Venna, Ramesh; Norcross, Michael A.; McMurtrey, Curtis P.; Hildebrand, William; Schuck, Peter; Natarajan, Kannan; Margulies, David H.

    2016-01-01

    Peptide loading of major histocompatibility complex class I (MHC-I) molecules is central to antigen presentation, self-tolerance, and CD8+ T-cell activation. TAP binding protein, related (TAPBPR), a widely expressed tapasin homolog, is not part of the classical MHC-I peptide-loading complex (PLC). Using recombinant MHC-I molecules, we show that TAPBPR binds HLA-A*02:01 and several other MHC-I molecules that are either peptide-free or loaded with low-affinity peptides. Fluorescence polarization experiments establish that TAPBPR augments peptide binding by MHC-I. The TAPBPR/MHC-I interaction is reversed by specific peptides, related to their affinity. Mutational and small-angle X-ray scattering (SAXS) studies confirm the structural similarities of TAPBPR with tapasin. These results support a role of TAPBPR in stabilizing peptide-receptive conformation(s) of MHC-I, permitting peptide editing. PMID:26869717

  9. Cloning and modeling of CD8 beta in the amphibian ambystoma Mexicanum. Evolutionary conserved structures for interactions with major histocompatibility complex (MHC) class I molecules.

    Science.gov (United States)

    Fellah, Julien S; Tuffèry, Pierre; Etchebest, Catherine; Guillet, Françoise; Bleux, Christian; Charlemagne, Jacques

    2002-04-17

    Mammalian and avian T-cells exhibit a large number of well characterized surface molecules associated with their maturation degree. Very little is known in comparison with T-cell differentiation in ectothermic vertebrates. This is mainly due to the lack of probes to identify T-cell subsets. We cloned and sequenced the first ectothermic CD8 beta DNA complementary to RNA from an amphibian species, the Mexican axolotl. The CD8 beta chain was 30-36% identical with its avian and mammalian homologues. The extracellular V-like domain contained the two typically conserved cysteines and was followed by a J-like sequence containing the canonical Phe-Gly-X-Gly stretch. The connecting peptide was much longer than in other species and contained potential O-glycosylation sites. The axolotl CD8 beta and major histocompatibility complex class I molecules were modeled using human HLA-A2/CD8 alphaalpha complex as template. The backbone conformation of axolotl CD8 beta matched well with the CD8 alpha-2 subunit of the human complex but significant structural differences were located in the CDR1, CDR2 and DE loops. Both axolotl and human class I showed large negative surface potential. The interacting area of the human CD8 alpha chain and of the corresponding region of axolotl CD8 beta had positive electrostatic potential compatible with complexation with the corresponding class I molecules. The presence of a CD8 beta homologue in an amphibian species implies that it was already present in the Devonian ancestor of amphibians and mammals, i.e. more than 400 million years ago. PMID:12034498

  10. One-pot, mix-and-read peptide-MHC tetramers.

    Directory of Open Access Journals (Sweden)

    Christian Leisner

    Full Text Available BACKGROUND: Cytotoxic T Lymphocytes (CTL recognize complexes of peptide ligands and Major Histocompatibility Complex (MHC class I molecules presented at the surface of Antigen Presenting Cells (APC. Detection and isolation of CTL's are of importance for research on CTL immunity, and development of vaccines and adoptive immune therapy. Peptide-MHC tetramers have become important reagents for detection and enumeration of specific CTL's. Conventional peptide-MHC-tetramer production involves recombinant MHC production, in vitro refolding, biotinylation and tetramerization; each step followed by various biochemical steps such as chromatographic purification, concentration etc. Such cumbersome production protocols have limited dissemination and restricted availability of peptide-MHC tetramers effectively precluding large-scale screening strategies involving many different peptide-MHC tetramers. METHODOLOGY/PRINCIPAL FINDINGS: We have developed an approach whereby any given tetramer specificity can be produced within 2 days with very limited effort and hands-on time. The strategy is based on the isolation of correctly oxidized, in vivo biotinylated recombinant MHC I heavy chain (HC. Such biotinylated MHC I HC molecules can be refolded in vitro, tetramerized with streptavidin, and used for specific T cell staining-all in a one-pot reaction without any intervening purification steps. CONCLUSIONS/SIGNIFICANCE: We have developed an efficient "one-pot, mix-and-read" strategy for peptide-MHC tetramer generation, and demonstrated specific T cell straining comparable to a commercially available MHC-tetramer. Here, seven peptide-MHC tetramers representing four different human MHC (HLA class I proteins have been generated. The technique should be readily extendable to any binding peptide and pre-biotinylated MHC (at this time we have over 40 different pre-biotinylated HLA proteins. It is simple, robust, and versatile technique with a very broad application

  11. Deletion of naïve T cells recognizing the minor histocompatibility antigen HY with toxin-coupled peptide-MHC class I tetramers inhibits cognate CTL responses and alters immunodominance

    OpenAIRE

    Hess, Sabrina M.; Young, Ellen F.; Miller, Keith R.; Vincent, Benjamin G.; Buntzman, Adam S.; Collins, Edward J.; Frelinger, Jeffrey A.; Hess, Paul R.

    2013-01-01

    Alloreactive T-cell responses directed against minor histocompatibility (H) antigens, which arise from diverse genetic disparities between donor and recipient outside the MHC, are an important cause of rejection of MHC-matched grafts. Because clinically significant responses appear to be directed at only a few antigens, the selective deletion of naïve T cells recognizing donor-specific, immunodominant minor H antigens in recipients before transplantation may be a useful tolerogenic strategy. ...

  12. The effect of up-regulation of MHC class I chain-related antigen A expression by dendritic cells on activity of NK cells%树突状细胞上调MHC Ⅰ类相关抗原A表达对NK细胞活性的影响

    Institute of Scientific and Technical Information of China (English)

    龚卫娟; 龚春香; 王长荣; 肖炜明; 钱莉; 季明春

    2011-01-01

    AIM: To observe whether MHC class I chain-related antigen A (MICA) was expressed on monocytes, immature dendritic calls ( iDCs), and mature dendritic cells (mDCs), and to study effect of up-regulation of MICA expression by DCs on biologic activity of NK cells.METHODS: MICA expression on monocytes, iDCs, or mDCs stimulated with LPS, TNF-α, CD40L, IL-15 or IFN-α was detected by flow cytometry. Next CD69 expression, degranuation, and IFN-γ production of NK cells stimulated with MICA-positive mDCs were analyzed. Lastly recombinant NKG2D/Fc fusion protein and anti-IL-12 monoclonal antibody was respectively added into culture systems to analyze whether these reagents affected the interaction between DCs and NK cells. RESULTS: MICA was not expressed on monocytes, and expressed on iDCs at low level. LPS,TNF-α, CD40L had no influences on MICA expression on mDCs, but IFN-α, IL-15 up-regulated MICA expression on mDCs. MICA-positive mDCs promoted CD69 expression,IFN-γ production, and killing K562 cells by NK cells.NKG2D/Fc inhibited both cytotcoxicity and IFN-γ secretion,whereas IL-12 antibody only inhibited IFN-γ secretion of NK cells. CONCLUSION: MICA expression on DCs is regulated by relevant factors in microenvironment. DCs with high level of MICA expression can up-regulate biologic activity of NK cells.%目的:观察单核细胞、未成熟和成熟树突状细胞(DCs)表达MHC Ⅰ类相关抗原A(MICA)的情况,以及DCs表达MICA后对NK细胞活性的影响.方法:用流式细胞术分别检测单核细胞、未成熟DC(iDCs)以及LPS、TNF-α、CD40L、IL-15和IFN-α分别刺激的成熟DCs表面MICA的表达,并观察DCs表达MICA后对NK细胞表达CD69、细胞毒活性和分泌IFN-γ的影响.最后用流式细胞术检测重组NKG2D/Fc蛋白和抗IL-12单克隆抗体(mAb)对DCs激活NK细胞的影响.结果:单核细胞不表达MICA,iDCs低表达MICA.LPS、TNF-α和CD40L对DCs表达MICA无影响;但IFN-α和IL-15可促进DC上调MICA表达.DCs表

  13. Cryopreservation of MHC Multimers: Recommendations for Quality Assurance in Detection of Antigen Specific T Cells

    OpenAIRE

    Hadrup, Sine Reker; Maurer, Dominik; Laske, Karoline; Frøsig, Thomas Mørch; Andersen, Sofie Ramskov; Britten, Cedrik M.; Sjoerd H van der Burg; Walter, Steffen; Gouttefangeas, Cécile

    2014-01-01

    Fluorescence-labeled peptide-MHC class I multimers serve as ideal tools for the detection of antigen-specific T cells by flow cytometry, enabling functional and phenotypical characterization of specific T cells at the single cell level. While this technique offers a number of unique advantages, MHC multimer reagents can be difficult to handle in terms of stability and quality assurance. The stability of a given fluorescence-labeled MHC multimer complex depends on both the stability of the pep...

  14. A Community Resource Benchmarking Predictions of Peptide Binding to MHC-I Molecules

    OpenAIRE

    Bjoern Peters; Huynh-Hoa Bui; Sune Frankild; Morten Nielson; Claus Lundegaard; Emrah Kostem; Derek Basch; Kasper Lamberth; Mikkel Harndahl; Ward Fleri; Wilson, Stephen S; John Sidney; Ole Lund; Soren Buus; Alessandro Sette

    2006-01-01

    Recognition of peptides bound to major histocompatibility complex (MHC) class I molecules by T lymphocytes is an essential part of immune surveillance. Each MHC allele has a characteristic peptide binding preference, which can be captured in prediction algorithms, allowing for the rapid scan of entire pathogen proteomes for peptide likely to bind MHC. Here we make public a large set of 48,828 quantitative peptide-binding affinity measurements relating to 48 different mouse, human, macaque, an...

  15. A community resource benchmarking predictions of peptide binding to MHC-I molecules.

    OpenAIRE

    Bjoern Peters; Huynh-Hoa Bui; Sune Frankild; Morten Nielson; Claus Lundegaard; Emrah Kostem; Derek Basch; Kasper Lamberth; Mikkel Harndahl; Ward Fleri; Wilson, Stephen S; John Sidney; Ole Lund; Soren Buus; Alessandro Sette

    2006-01-01

    Recognition of peptides bound to major histocompatibility complex (MHC) class I molecules by T lymphocytes is an essential part of immune surveillance. Each MHC allele has a characteristic peptide binding preference, which can be captured in prediction algorithms, allowing for the rapid scan of entire pathogen proteomes for peptide likely to bind MHC. Here we make public a large set of 48,828 quantitative peptide-binding affinity measurements relating to 48 different mouse, human, macaque, an...

  16. A community resource benchmarking predictions of peptide binding to MHC-I molecules

    OpenAIRE

    Peters, B; Bui, HH; Pletscher-Frankild, Sune; Nielsen, Morten; Lundegaard, Claus; Kostem, E; Basch, D; Lamberth, K.; Harndahl, M.; Fleri, W.; Wilson, SS; Sidney, J; Lund, Ole; Buus, S.; Sette, Alessandro

    2006-01-01

    Recognition of peptides bound to major histocompatibility complex (MHC) class I molecules by T lymphocytes is an essential part of immune surveillance. Each MHC allele has a characteristic peptide binding preference, which can be captured in prediction algorithms, allowing for the rapid scan of entire pathogen proteomes for peptide likely to bind MHC. Here we make public a large set of 48,828 quantitative peptide-binding affinity measurements relating to 48 different mouse, human, macaque, an...

  17. Comparative Genome Analyses Reveal Distinct Structure in the Saltwater Crocodile MHC

    OpenAIRE

    Jaratlerdsiri, Weerachai; Deakin, Janine; Ricardo M Godinez; Shan, Xueyan; Peterson, Daniel G.; Marthey, Sylvain; Lyons, Eric; McCarthy, Fiona M.; Isberg, Sally R.; Higgins, Damien P.; Chong, Amanda Y; St John, John; Glenn, Travis C.; Ray, David A.; Gongora, Jaime

    2014-01-01

    The major histocompatibility complex (MHC) is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. The MHC is generally divided into subregions (classes I, II and III) containing genes of similar function across species, but with different gene number and organisation. Crocodylia (crocodilians) are widely distributed and represent an evolutionary distinct group among higher vertebrates, but the genomic organisation of MHC wit...

  18. The diversity of bovine MHC class II DRB3 and DQA1 alleles in different herds of Japanese Black and Holstein cattle in Japan.

    Science.gov (United States)

    Miyasaka, Taku; Takeshima, Shin-nosuke; Matsumoto, Yuki; Kobayashi, Naohiko; Matsuhashi, Tamako; Miyazaki, Yoshiyuki; Tanabe, Yoshihiro; Ishibashi, Kazuki; Sentsui, Hiroshi; Aida, Yoko

    2011-02-01

    In cattle, bovine leukocyte antigens (BoLAs) have been extensively used as markers for bovine diseases and immunological traits. In this study, we sequenced alleles of the BoLA class II loci, BoLA-DRB3 and BoLA-DQA1, from 650 Japanese cattle from six herds [three herds (507 animals) of Japanese Black cattle and three herds (143 animals) of Holstein cattle] using polymerase chain reaction-sequence-based typing (PCR-SBT) methods. We identified 26 previously reported distinct DRB3 alleles in the two populations: 22 in Japanese Black and 17 in Holstein. The number of DRB3 alleles detected in each herd ranged from 9 to 20. Next, we identified 15 previously reported distinct DQA1 alleles: 13 in Japanese Black and 10 in Holstein. The number of alleles in each herd ranged from 6 to 10. Thus, allelic divergence is significantly greater for DRB3 than for DQA1. A population tree on the basis of the frequencies of the DRB3 and DQA1 alleles showed that, although the genetic distance differed significantly between the two cattle breeds, it was closely related within the three herds of each breed. In addition, Wu-Kabat variability analysis indicated that the DRB3 gene was more polymorphic than the DQA1 gene in both breeds and in all herds, and that the majority of the hypervariable positions within both loci corresponded to pocket-forming residues. The DRB3 and DQA1 heterozygosity for both breeds within each herd were calculated based on the Hardy-Weinberg equilibrium. Only one Japanese Black herd showed a significant difference between the expected and observed heterozygosity at both loci. This is the first report presenting a detailed study of the allelic distribution of BoLA-DRB3 and -DQA1 genes in Japanese Black and Holstein cattle from different farms in Japan. These results may help to develop improved livestock breeding strategies in the future. PMID:20965236

  19. Evolution of major histocompatibility complex class I and class II genes in the brown bear

    Directory of Open Access Journals (Sweden)

    Kuduk Katarzyna

    2012-10-01

    Full Text Available Abstract Background Major histocompatibility complex (MHC proteins constitute an essential component of the vertebrate immune response, and are coded by the most polymorphic of the vertebrate genes. Here, we investigated sequence variation and evolution of MHC class I and class II DRB, DQA and DQB genes in the brown bear Ursus arctos to characterise the level of polymorphism, estimate the strength of positive selection acting on them, and assess the extent of gene orthology and trans-species polymorphism in Ursidae. Results We found 37 MHC class I, 16 MHC class II DRB, four DQB and two DQA alleles. We confirmed the expression of several loci: three MHC class I, two DRB, two DQB and one DQA. MHC class I also contained two clusters of non-expressed sequences. MHC class I and DRB allele frequencies differed between northern and southern populations of the Scandinavian brown bear. The rate of nonsynonymous substitutions (dN exceeded the rate of synonymous substitutions (dS at putative antigen binding sites of DRB and DQB loci and, marginally significantly, at MHC class I loci. Models of codon evolution supported positive selection at DRB and MHC class I loci. Both MHC class I and MHC class II sequences showed orthology to gene clusters found in the giant panda Ailuropoda melanoleuca. Conclusions Historical positive selection has acted on MHC class I, class II DRB and DQB, but not on the DQA locus. The signal of historical positive selection on the DRB locus was particularly strong, which may be a general feature of caniforms. The presence of MHC class I pseudogenes may indicate faster gene turnover in this class through the birth-and-death process. South–north population structure at MHC loci probably reflects origin of the populations from separate glacial refugia.

  20. One-pot, mix-and-read peptide-MHC tetramers

    DEFF Research Database (Denmark)

    Leisner, Christian Valdemar Vinge; Loeth, Nina; Lamberth, Kasper;

    2008-01-01

    BACKGROUND: Cytotoxic T Lymphocytes (CTL) recognize complexes of peptide ligands and Major Histocompatibility Complex (MHC) class I molecules presented at the surface of Antigen Presenting Cells (APC). Detection and isolation of CTL's are of importance for research on CTL immunity, and development...... of vaccines and adoptive immune therapy. Peptide-MHC tetramers have become important reagents for detection and enumeration of specific CTL's. Conventional peptide-MHC-tetramer production involves recombinant MHC production, in vitro refolding, biotinylation and tetramerization; each step followed by various...... biochemical steps such as chromatographic purification, concentration etc. Such cumbersome production protocols have limited dissemination and restricted availability of peptide-MHC tetramers effectively precluding large-scale screening strategies involving many different peptide-MHC tetramers. METHODOLOGY...

  1. Proteome-wide screening reveals immunodominance in the CD8 T cell response against classical swine fever virus with antigen-specificity dependent on MHC class I haplotype expression.

    Directory of Open Access Journals (Sweden)

    Giulia Franzoni

    Full Text Available Vaccination with live attenuated classical swine fever virus (CSFV vaccines induces a rapid onset of protection which has been associated with virus-specific CD8 T cell IFN-γ responses. In this study, we assessed the specificity of this response, by screening a peptide library spanning the CSFV C-strain vaccine polyprotein to identify and characterise CD8 T cell epitopes. Synthetic peptides were pooled to represent each of the 12 CSFV proteins and used to stimulate PBMC from four pigs rendered immune to CSFV by C-strain vaccination and subsequently challenged with the virulent Brescia strain. Significant IFN-γ expression by CD8 T cells, assessed by flow cytometry, was induced by peptide pools representing the core, E2, NS2, NS3 and NS5A proteins. Dissection of these antigenic peptide pools indicated that, in each instance, a single discrete antigenic peptide or pair of overlapping peptides was responsible for the IFN-γ induction. Screening and titration of antigenic peptides or truncated derivatives identified the following antigenic regions: core₂₄₁₋₂₅₅ PESRKKLEKALLAWA and NS3₁₉₀₂₋₁₉₁₂ VEYSFIFLDEY, or minimal length antigenic peptides: E2₉₉₆₋₁₀₀₃ YEPRDSYF, NS2₁₂₂₃₋₁₂₃₀ STVTGIFL and NS5A₃₀₇₀₋₃₀₇₈ RVDNALLKF. The epitopes are highly conserved across CSFV strains and variable sequence divergence was observed with related pestiviruses. Characterisation of epitope-specific CD8 T cells revealed evidence of cytotoxicity, as determined by CD107a mobilisation, and a significant proportion expressed TNF-α in addition to IFN-γ. Finally, the variability in the antigen-specificity of these immunodominant CD8 T cell responses was confirmed to be associated with expression of distinct MHC class I haplotypes. Moreover, recognition of NS₁₂₂₃₋₁₂₃₀ STVTGIFL and NS3₁₉₀₂₋₁₉₁₂ VEYSFIFLDEY by a larger group of C-strain vaccinated animals showed

  2. MHC-Ⅰ类相关分子A表达在食管癌患者术后自然杀伤细胞免疫治疗中的作用%Role of MHC class Ⅰ-related molecules A on NK cells immunotherapy in esophageal cancer patients after operation

    Institute of Scientific and Technical Information of China (English)

    柳硕岩; 周智锋; 李洁羽; 郑庆丰; 王枫; 陈啸风; 叶韵斌

    2013-01-01

    目的 探讨MHC-Ⅰ类相关分子A(MICA)分子表达与早期食管癌患者术后自然杀伤(NK)细胞过继免疫治疗的相关性,并分析MICA表达在NK细胞治疗中的意义.方法 100例食管癌患者分为单纯手术组40例、MICA阴性NK细胞治疗组(MICA-组)30例及MICA阳性NK细胞治疗组(MICA+组)30例,分别于手术前及手术后60d检测患者外周血CD3+、CD4+、CD4+/CD8+、NK细胞比例、调节性T细胞(Treg细胞)比例、Th1/Th2/Th17细胞因子水平、血清抗体IgA、IgM、IgG以及肿瘤标志物CEA、SCC、CA199、CYFRA21-1等的变化,初步评价患者近期疗效.结果 MICA+组患者外周血CD3+、CD4+、NK细胞阳性率及CD4+/CD8+比例明显高于治疗前[(68.3±7.6)%比(56.2±4.1)%,(39.8±8.2)%比(30.8±4.7)%,(22.2±4.7)%比(18.7±5.5)%,(1.49±0.30)比(1.15±0.61);均P<0.05],Treg细胞阳性率明显低于治疗前[(8.1±4.0)%比(13.4±4.5)%,P<0.05],CD8+细胞阳性率治疗前后差异无统计学意义[(26.9±6.2)%比(27.8±7.1)%,P>0.05].MICA+组患者外周血中Th1类细胞因子(包括IL-2、IFN-γ和TNF-α)水平增高,Th2类细胞因子(IL-4、IL-6、IL-10)水平降低(P<0.05),但Th17细胞因子水平差异无统计学意义(P>0.05).同时提高IgA、IgM、IgG含量,但NK细胞治疗前后肿瘤标志物CEA、SCC、CA199、CYFRA21-1差异无统计学意义(P>0.05).结论 早期食管癌组织MICA表达阳性患者进行NK细胞过继免疫治疗能有效提高细胞免疫及体液免疫水平.%Objective To explore the relevance of expression of MHC class Ⅰ-related molecules A (MICA) molecule and NK cells immunotherapy in esophageal cancer patients after operation.To analyze the significance of MICA expression in NK cell immunotherapy.Methods 100 patients of esophageal cancer were divided into 3 group,surgical alone group,MICA negative with NK therapy group (MICA-group) and MICA positive with NK therapy group (MICA+ group).The immunity indicators and tumor markers

  3. Analysis of porcine MHC using microarrays.

    Science.gov (United States)

    Gao, Yu; Wahlberg, Per; Marthey, Sylvain; Esquerré, Diane; Jaffrézic, Florence; Lecardonnel, Jérome; Hugot, Karine; Rogel-Gaillard, Claire

    2012-07-15

    The major histocompatibility complex (MHC) in Mammals is one of the most gene dense regions of the genome and contains the polymorphic histocompatibility gene families known to be involved in pathogen response and control of auto-immunity. The MHC is a complex genetic system that provides an interesting model system to study genome expression regulation and genetic diversity at the megabase scale. The pig MHC or SLA (Swine Leucocyte Antigen) complex spans 2.4 megabases and 151 loci have been annotated. We will review key results from previous RNA expression studies using microarrays containing probes specific to annotated loci within SLA and in addition present novel data obtained using high-density tiling arrays encompassing the whole SLA complex. We have focused on transcriptome modifications of porcine peripheral blood mononuclear cells stimulated with a mixture of phorbol myristate acetate and ionomycin known to activate B and T cell proliferation. Our results show that numerous loci mapping to the SLA complex are affected by the treatment. A general decreased level of expression for class I and II genes and an up-regulation of genes involved in peptide processing and transport were observed. Tiling array-based experiments contributed to refined gene annotations as presented for one SLA class I gene referred to as SLA-11. In conclusion, high-density tiling arrays can serve as an excellent tool to draw comprehensive transcription maps, and improve genome annotations for the SLA complex. We are currently studying their relevance to characterize SLA genetic diversity in combination with high throughput next generation sequencing. PMID:21561666

  4. 外源性抗原对内皮细胞MHC-I类链相关基因A表达的影响%Effect of exogenous antigen on expression of major histocompatibility complex class I chain-related gene A in endothelial cells***☆

    Institute of Scientific and Technical Information of China (English)

    王云炎; 侯建全; 何军; 袁晓妮; 张江磊; 温端改

    2011-01-01

    BACKGROUND: Studies have demonstrated that incidence rate of acute rejection in renal transplant recipients with pre-production of major histocompatibility complex class I chain-related gene A (MICA), including parts of autoantibody, before transplantation in body, is obviously greater than that of recipients with negative antibody. OBJECTIVE: To investigate effects of exogenous antigen on MICA expression in endothelial cells. METHODS: The endothelial cells were cultured with exogenous recombinant MICA protein (group M5, M10 and M25) and heat shock protein-70 (group H5, H10 and H25) with dosages of 5, 10 and 25 μg/L, respectively, for 48 hours. Same volume of phosphate buffer saline was added into the control groups. RESULTS AND CONCLUSION: At 48 hours after induction, the expressions of MICA mRNA and protein were increased significantly in each experimental group (M5, M10 and M25) than that of the control group with significant (P 0.05). The expression of MICA membrane protein in the group M10 was obviously greater than that of the group M5 and M25 (P 0.05). However, the expression of MICA gene and sMICA level did not change after heat shock protein-70 stimulation. The exogenous MICA antigen up-regulates the expression of MICA mRNA and protein, especially increases the expression of membrane protein on the cell surface significantly, but sMICA in supernatant was dramatically decreased.%背景:研究表明部分肾移植受者在移植前就产生了MHC-I类链相关基因A(MICA)抗体,包括部分自身抗体,其急性排斥反应发生率明显高于抗体阴性者.目的:探讨外源性抗原对内皮细胞MICA表达的影响.方法:分别以5,10和25 μg/L 3个剂量,将MICA重组蛋白分为M5,M10,M25组,将热休克蛋白分为H5,H10,H25组,对人脐静脉内皮细胞予以诱导培养48 h,对照组加入等量的磷酸盐缓冲液.结果与结论:用MICA重组蛋白诱导48 h后,各实验组(M5,M10,M25)内皮细胞MICA mRNA和MICA蛋白的表达量与对

  5. Genetic variation at the MHC in a population of introduced wild turkeys.

    Science.gov (United States)

    Bauer, Miranda M; Miller, Marcia M; Briles, W Elwood; Reed, Kent M

    2013-01-01

    Genetic variation in the major histocompatibility complex (MHC) is known to affect disease resistance in many species. Investigations of MHC diversity in populations of wild species have focused on the antigen presenting class IIβ molecules due to the known polymorphic nature of these genes and the role these molecules play in pathogen recognition. Studies of MHC haplotype variation in the turkey ( Meleagris gallopavo ) are limited. This study was designed to examine MHC diversity in a group of Eastern wild turkeys ( Meleagris gallopavo silvestris ) collected during population expansion following reintroduction of the species in southern Wisconsin, USA. Southern blotting with BG and class IIβ probes and single nucleotide polymorphism (SNP) genotyping was used to measure MHC variation. SNP analysis focused on single copy MHC genes flanking the highly polymorphic class IIβ genes. Southern blotting identified 27 class IIβ phenotypes, whereas SNP analysis identified 13 SNP haplotypes occurring in 28 combined genotypes. Results show that genetic diversity estimates based on RFLP (Southern blot) analysis underestimate the level of variation detected by SNP analysis. Sequence analysis of the mitochondrial D-loop identified 7 mitochondrial haplotypes (mitotypes) in the sampled birds. Results show that wild turkeys located in southern Wisconsin have a genetically diverse MHC and originate from several maternal lineages.

  6. The bovine class II major histocompatibility complex: Serological definition and further characterization of class II haplotypes.

    NARCIS (Netherlands)

    Nilsson, Ph.R.

    1994-01-01

    In this thesis an analysis of the major histocompatibility complex (MHC) class II in cattle is reported, with emphasis on the development of class II serology. First, the production of class II alloantisera, and the serological definition of bovine MHC class II polymorphism is described. Subsequentl

  7. CIITA and its dual roles in MHC gene transcription

    Directory of Open Access Journals (Sweden)

    Dinah S. Singer

    2013-12-01

    Full Text Available CIITA is a transcriptional co-activator that regulates γ-interferon-activated transcription of Major Histocompatibility Complex (MHC class I and class II genes. As such, it plays a critical role in immune responses: CIITA deficiency results in aberrant MHC gene expression and consequently in autoimmune diseases such as Type II bare lymphocyte syndrome. Although CIITA does not bind DNA directly, it regulates MHC transcription in two distinct ways– as a transcriptional activator and as a general transcription factor. As an activator, CIITA nucleates an enhanceosome consisting of the DNA binding transcription factors RFX, CREB and NF-Y. As a general transcription factor, CIITA functionally replaces the TFIID component, TAF1. Like TAF1, CIITA possesses acetyltransferase (AT and kinase activities, both of which contribute to proper transcription of MHC class I and II genes. The substrate specificity and regulation of the CIITA AT and kinase activities also parallel those of TAF1. In addition, CIITA is tightly regulated by its various regulatory domains that undergo phosphorylation and influence its targeted localization. Thus, a complex picture of the mechanisms regulating CIITA function is emerging suggesting that CIITA has dual roles in transcriptional regulation which are summarized in this review.

  8. Virus encoded MHC-like decoys diversify the inhibitory KIR repertoire.

    Directory of Open Access Journals (Sweden)

    Paola Carrillo-Bustamante

    Full Text Available Natural killer (NK cells are circulating lymphocytes that play an important role in the control of viral infections and tumors. Their functions are regulated by several activating and inhibitory receptors. A subset of these receptors in human NK cells are the killer immunoglobulin-like receptors (KIRs, which interact with the highly polymorphic MHC class I molecules. One important function of NK cells is to detect cells that have down-regulated MHC expression (missing-self. Because MHC molecules have non polymorphic regions, their expression could have been monitored with a limited set of monomorphic receptors. Surprisingly, the KIR family has a remarkable genetic diversity, the function of which remains poorly understood. The mouse cytomegalovirus (MCMV is able to evade NK cell responses by coding "decoy" molecules that mimic MHC class I. This interaction was suggested to have driven the evolution of novel NK cell receptors. Inspired by the MCMV system, we develop an agent-based model of a host population infected with viruses that are able to evolve MHC down-regulation and decoy molecules. Our simulations show that specific recognition of MHC class I molecules by inhibitory KIRs provides excellent protection against viruses evolving decoys, and that the diversity of inhibitory KIRs will subsequently evolve as a result of the required discrimination between host MHC molecules and decoy molecules.

  9. Mate choice for neutral and MHC genetic characteristics in Alpine marmots: different targets in different contexts?

    Science.gov (United States)

    Ferrandiz-Rovira, Mariona; Allainé, Dominique; Callait-Cardinal, Marie-Pierre; Cohas, Aurélie

    2016-07-01

    Sexual selection through female mate choice for genetic characteristics has been suggested to be an important evolutionary force maintaining genetic variation in animal populations. However, the genetic targets of female mate choice are not clearly identified and whether female mate choice is based on neutral genetic characteristics or on particular functional loci remains an open question. Here, we investigated the genetic targets of female mate choice in Alpine marmots (Marmota marmota), a socially monogamous mammal where extra-pair paternity (EPP) occurs. We used 16 microsatellites to describe neutral genetic characteristics and two MHC loci belonging to MHC class I and II as functional genetic characteristics. Our results reveal that (1) neutral and MHC genetic characteristics convey different information in this species, (2) social pairs show a higher MHC class II dissimilarity than expected under random mate choice, and (3) the occurrence of EPP increases when social pairs present a high neutral genetic similarity or dissimilarity but also when they present low MHC class II dissimilarity. Thus, female mate choice is based on both neutral and MHC genetic characteristics, and the genetic characteristics targeted seem to be context dependent (i.e., the genes involved in social mate choice and genetic mate choice differ). We emphasize the need for empirical studies of mate choice in the wild using both neutral and MHC genetic characteristics because whether neutral and functional genetic characteristics convey similar information is not universal. PMID:27386072

  10. Major histocompatibility complex class II compatibility, but not class I, predicts mate choice in a bird with highly developed olfaction.

    Science.gov (United States)

    Strandh, Maria; Westerdahl, Helena; Pontarp, Mikael; Canbäck, Björn; Dubois, Marie-Pierre; Miquel, Christian; Taberlet, Pierre; Bonadonna, Francesco

    2012-11-01

    Mate choice for major histocompatibility complex (MHC) compatibility has been found in several taxa, although rarely in birds. MHC is a crucial component in adaptive immunity and by choosing an MHC-dissimilar partner, heterozygosity and potentially broad pathogen resistance is maximized in the offspring. The MHC genotype influences odour cues and preferences in mammals and fish and hence olfactory-based mate choice can occur. We tested whether blue petrels, Halobaena caerulea, choose partners based on MHC compatibility. This bird is long-lived, monogamous and can discriminate between individual odours using olfaction, which makes it exceptionally well suited for this analysis. We screened MHC class I and II B alleles in blue petrels using 454-pyrosequencing and quantified the phylogenetic, functional and allele-sharing similarity between individuals. Partners were functionally more dissimilar at the MHC class II B loci than expected from random mating (p = 0.033), whereas there was no such difference at the MHC class I loci. Phylogenetic and non-sequence-based MHC allele-sharing measures detected no MHC dissimilarity between partners for either MHC class I or II B. Our study provides evidence of mate choice for MHC compatibility in a bird with a high dependency on odour cues, suggesting that MHC odour-mediated mate choice occurs in birds.

  11. Multi-parametric analysis of host response to murine CMV in MHC class I disparate mice reveals primacy of Dk-licensed Ly49G2+ NK cells in viral control2, 3

    Science.gov (United States)

    Prince, Jessica; Lundgren, Alyssa; Stadnisky, Michael D.; Nash, William T.; Beeber, Amira; Turner, Stephen D.; Brown, Michael G.

    2013-01-01

    MHC I Dk and Ly49G2 inhibitory receptor-expressing NK cells are essential to murine (M)CMV5 resistance in MA/My mice. Without Dk, Ly49G2+ NK cells in C57L mice fail to protect against MCMV infection. As a cognate ligand of Ly49G2, Dk licenses Ly49G2+ NK cells for effector activity. These data suggested that Dk-licensed Ly49G2+ NK cells might recognize and control MCMV infection. However, a role for licensed NK cells in viral immunity is uncertain. We combined classical genetics with flow cytometry to visualize the host response to MCMV. Immune cells collected from individuals of a diverse cohort of MA/MyxC57L offspring segregating Dk were examined before and after infection, including Ly49+ NK subsets, receptor expression features and other phenotypic traits. To identify critical NK cell features, automated analysis of 110 traits was performed in R using Pearson’s correlation followed with a Bonferroni correction for multiple tests. Hierarchical clustering of trait-associations and principal component analyses were used to discern shared immune response and genetic relationships. The results demonstrate that Ly49G2 expression on naïve blood NK cells was predictive of MCMV resistance. However, rapid Ly49G2+ NK cell expansion following viral exposure selectively occurred in Dk offspring; this response was more highly correlated to MCMV control than all other immune cell features. We infer that Dk-licensed Ly49G2+ NK cells efficiently detected missing-self MHC cues on viral targets, which elicited cellular expansion and target cell killing. MHC polymorphism therefore regulates licensing and detection of viral targets by distinct subsets of NK cells required in innate viral control. PMID:24068668

  12. Evidence for selection maintaining MHC diversity in a rodent species despite strong density fluctuations.

    Science.gov (United States)

    Schuster, Andrea C; Herde, Antje; Mazzoni, Camila J; Eccard, Jana A; Sommer, Simone

    2016-07-01

    Strong spatiotemporal variation in population size often leads to reduced genetic diversity limiting the adaptive potential of individual populations. Key genes of adaptive variation are encoded by the immune genes of the major histocompatibility complex (MHC) playing an essential role in parasite resistance. How MHC variation persists in rodent populations that regularly experience population bottlenecks remains an important topic in evolutionary genetics. We analysed the consequences of strong population fluctuations on MHC class II DRB exon 2 diversity in two distant common vole (Microtus arvalis) populations in three consecutive years using a high-throughput sequencing approach. In 143 individuals, we detected 25 nucleotide alleles translating into 14 unique amino acid MHC alleles belonging to at least three loci. Thus, the overall allelic diversity and amino acid distance among the remaining MHC alleles, used as a surrogate for the range of pathogenic antigens that can be presented to T-cells, are still remarkably high. Both study populations did not show significant population differentiation between years, but significant differences were found between sites. We concluded that selection processes seem to be strong enough to maintain moderate levels of MHC diversity in our study populations outcompeting genetic drift, as the same MHC alleles were conserved between years. Differences in allele frequencies between populations might be the outcome of different local parasite pressures and/or genetic drift. Further understanding of how pathogens vary across space and time will be crucial to further elucidate the mechanisms maintaining MHC diversity in cyclic populations. PMID:27225422

  13. Interplay among coactivator-associated arginine methyltransferase 1, CBP, and CIITA in IFN-γ-inducible MHC-II gene expression

    OpenAIRE

    Zika, Eleni; Fauquier, Lucas; Vandel, Laurence; Ting, Jenny P.-Y.

    2005-01-01

    Class II major histocompatibility (MHC-II) genes are prototype targets of IFN-γ. IFN-γ activates the expression of the non-DNA-binding master regulator of MHC-II, class II transactivator (CIITA), which is crucial for enhanceosome formation and gene activation. This report shows the importance of the histone methyltransferase, coactivator-associated arginine methyltransferase (CARM1/PRMT4), during IFN-γ-induced MHC-II gene activation. It also demonstrates the coordinated regulation of CIITA, C...

  14. Regulated expression of an introduced MHC H-2K bm1 gene in murine embryonal carcinoma cells.

    NARCIS (Netherlands)

    A. Rosenthal; S. Wright; H. Cedar; R.A. Flavell (Richard); F.G. Grosveld (Frank)

    1984-01-01

    textabstractThe transplantation antigens H-2K, H-2D and H-2L are developmentally regulated, highly polymorphic cell surface proteins encoded by the major histocompatibility gene complex (MHC). First detectable on the early embryo, they are subsequently expressed on most somatic cells of the adult mo

  15. Signature Patterns of MHC Diversity in Three Gombe Communities of Wild Chimpanzees Reflect Fitness in Reproduction and Immune Defense against SIVcpz.

    Directory of Open Access Journals (Sweden)

    Emily E Wroblewski

    2015-05-01

    Full Text Available Major histocompatibility complex (MHC class I molecules determine immune responses to viral infections. These polymorphic cell-surface glycoproteins bind peptide antigens, forming ligands for cytotoxic T and natural killer cell receptors. Under pressure from rapidly evolving viruses, hominoid MHC class I molecules also evolve rapidly, becoming diverse and species-specific. Little is known of the impact of infectious disease epidemics on MHC class I variant distributions in human populations, a context in which the chimpanzee is the superior animal model. Population dynamics of the chimpanzees inhabiting Gombe National Park, Tanzania have been studied for over 50 years. This population is infected with SIVcpz, the precursor of human HIV-1. Because HLA-B is the most polymorphic human MHC class I molecule and correlates strongly with HIV-1 progression, we determined sequences for its ortholog, Patr-B, in 125 Gombe chimpanzees. Eleven Patr-B variants were defined, as were their frequencies in Gombe's three communities, changes in frequency with time, and effect of SIVcpz infection. The growing populations of the northern and central communities, where SIVcpz is less prevalent, have stable distributions comprising a majority of low-frequency Patr-B variants and a few high-frequency variants. Driving the latter to high frequency has been the fecundity of immigrants to the northern community, whereas in the central community, it has been the fecundity of socially dominant individuals. In the declining population of the southern community, where greater SIVcpz prevalence is associated with mortality and emigration, Patr-B variant distributions have been changing. Enriched in this community are Patr-B variants that engage with natural killer cell receptors. Elevated among SIVcpz-infected chimpanzees, the Patr-B*06:03 variant has striking structural and functional similarities to HLA-B*57, the human allotype most strongly associated with delayed HIV-1

  16. Statistical deconvolution of enthalpic energetic contributions to MHC-peptide binding affinity

    Directory of Open Access Journals (Sweden)

    Drew Michael GB

    2006-03-01

    Full Text Available Abstract Background MHC Class I molecules present antigenic peptides to cytotoxic T cells, which forms an integral part of the adaptive immune response. Peptides are bound within a groove formed by the MHC heavy chain. Previous approaches to MHC Class I-peptide binding prediction have largely concentrated on the peptide anchor residues located at the P2 and C-terminus positions. Results A large dataset comprising MHC-peptide structural complexes was created by re-modelling pre-determined x-ray crystallographic structures. Static energetic analysis, following energy minimisation, was performed on the dataset in order to characterise interactions between bound peptides and the MHC Class I molecule, partitioning the interactions within the groove into van der Waals, electrostatic and total non-bonded energy contributions. Conclusion The QSAR techniques of Genetic Function Approximation (GFA and Genetic Partial Least Squares (G/PLS algorithms were used to identify key interactions between the two molecules by comparing the calculated energy values with experimentally-determined BL50 data. Although the peptide termini binding interactions help ensure the stability of the MHC Class I-peptide complex, the central region of the peptide is also important in defining the specificity of the interaction. As thermodynamic studies indicate that peptide association and dissociation may be driven entropically, it may be necessary to incorporate entropic contributions into future calculations.

  17. Characterization of the oligodeoxynucleotide-mediated inhibition of interferon-gamma-induced major histocompatibility complex class I and intercellular adhesion molecule-1.

    Science.gov (United States)

    Ramanathan, M; Lantz, M; MacGregor, R D; Garovoy, M R; Hunt, C A

    1994-10-01

    The major histocompatibility complex (MHC) Class I and II genes and intercellular adhesion molecule-1 (ICAM-1) are regulated by interferon-gamma in a variety of cell types. We have previously shown that the oligodeoxynucleotide 5'-GGG GTT GGT TGT GTT GGG TGT TGT GT-RNH2 (oligo I) inhibits the interferon-gamma-mediated enhancement of MHC Class I and ICAM-1 proteins in the K562 cell line. We have now investigated the mechanism of action of oligo I and report that it acts by inhibiting the binding of interferon-gamma to cells. We also show that the dose-response curves, the selectivity profile, and the kinetics of oligo I are consistent with this novel mechanism of action. The dose-response curves for oligo I, obtained using antibodies against the MHC Class I heavy chain, beta 2-microglobulin, or ICAM-1, are almost superimposable at each observation time. MHC Class I induction by 6400 units/ml interferon-alpha or interferon-beta or ICAM-1 enhancement by 800 units/ml tumor necrosis factor-alpha is not inhibited by oligo I. However, the synergistic induction of MHC Class I by mixtures of tumor necrosis factor-alpha and interferon-gamma is inhibited. Oligo I belongs to a class of active oligodeoxynucleotides that inhibits interferon-gamma-induced MHC Class I and ICAM-1 in K562 cells. The activity and potency is sequence-dependent, but remarkably different sequences can have comparable effects. The activity of oligo I in the HeLa S3 cell line inhibits the interferon-gamma-mediated enhancement of both ICAM-1 and MHC Class II DR and the interferon-gamma-mediated reduction in transferrin receptor expression. Thus, oligo I appears to specifically inhibit interferon-gamma-induced changes in protein expression, which is consistent with oligo I acting at an early step(s) in the induction process. Taken together, our results show that oligo I exerts its effects by inhibiting the association of interferon-gamma with the cell surface, which is a novel mechanism of action for

  18. Systematic Characterisation of Cellular Localisation and Expression Profiles of Proteins Containing MHC Ligands

    DEFF Research Database (Denmark)

    Juncker, Agnieszka; Larsen, Mette Voldby; Weinhold, Nils;

    2009-01-01

    -scale study, we used a large data set of proteins containing experimentally identified MHC class I or II ligands and examined the proteins according to their expression profiles at the mRNA level and their Gene Ontology (GO) classification within the cellular component ontology. Proteins encoded by highly...... the nature of MHC ligand-containing proteins and can be used to extend the existing methods for MHC ligand predictions by including the source protein's localisation and expression profile. Improving the current methods is important in the growing quest for epitopes that can be used for vaccine or diagnostic...

  19. Gene duplication and divergence produce divergent MHC genotypes without disassortative mating.

    Science.gov (United States)

    Dearborn, Donald C; Gager, Andrea B; McArthur, Andrew G; Gilmour, Morgan E; Mandzhukova, Elena; Mauck, Robert A

    2016-09-01

    Genes of the major histocompatibility complex (MHC) exhibit heterozygote advantage in immune defence, which in turn can select for MHC-disassortative mate choice. However, many species lack this expected pattern of MHC-disassortative mating. A possible explanation lies in evolutionary processes following gene duplication: if two duplicated MHC genes become functionally diverged from each other, offspring will inherit diverse multilocus genotypes even under random mating. We used locus-specific primers for high-throughput sequencing of two expressed MHC Class II B genes in Leach's storm-petrels, Oceanodroma leucorhoa, and found that exon 2 alleles fall into two gene-specific monophyletic clades. We tested for disassortative vs. random mating at these two functionally diverged Class II B genes, using multiple metrics and different subsets of exon 2 sequence data. With good statistical power, we consistently found random assortment of mates at MHC. Despite random mating, birds had MHC genotypes with functionally diverged alleles, averaging 13 amino acid differences in pairwise comparisons of exon 2 alleles within individuals. To test whether this high MHC diversity in individuals is driven by evolutionary divergence of the two duplicated genes, we built a phylogenetic permutation model. The model showed that genotypic diversity was strongly impacted by sequence divergence between the most common allele of each gene, with a smaller additional impact of monophyly of the two genes. Divergence of allele sequences between genes may have reduced the benefits of actively seeking MHC-dissimilar mates, in which case the evolutionary history of duplicated genes is shaping the adaptive landscape of sexual selection. PMID:27376487

  20. HIV-1 Nef and Vpu Are Functionally Redundant Broad-Spectrum Modulators of Cell Surface Receptors, Including Tetraspanins

    Science.gov (United States)

    Haller, Claudia; Müller, Birthe; Fritz, Joëlle V.; Lamas-Murua, Miguel; Stolp, Bettina; Pujol, François M.; Keppler, Oliver T.

    2014-01-01

    ABSTRACT HIV-1 Nef and Vpu are thought to optimize virus replication in the infected host, at least in part via their ability to interfere with vesicular host cell trafficking. Despite the use of distinct molecular mechanisms, Nef and Vpu share specificity for some molecules such as CD4 and major histocompatibility complex class I (MHC-I), while disruption of intracellular transport of the host cell restriction factor CD317/tetherin represents a specialized activity of Vpu not exerted by HIV-1 Nef. To establish a profile of host cell receptors whose intracellular transport is affected by Nef, Vpu, or both, we comprehensively analyzed the effect of these accessory viral proteins on cell surface receptor levels on A3.01 T lymphocytes. Thirty-six out of 105 detectable receptors were significantly downregulated by HIV-1 Nef, revealing a previously unappreciated scope with which HIV-1 Nef remodels the cell surface of infected cells. Remarkably, the effects of HIV-1 Vpu on host cell receptor exposure largely matched those of HIV-1 Nef in breadth and specificity (32 of 105, all also targeted by Nef), even though the magnitude was generally less pronounced. Of particular note, cell surface exposure of all members of the tetraspanin (TSPAN) protein family analyzed was reduced by both Nef and Vpu, and the viral proteins triggered the enrichment of TSPANs in a perinuclear area of the cell. While Vpu displayed significant colocalization and physical association with TSPANs, interactions of Nef with TSPANs were less robust. TSPANs thus emerge as a major target of deregulation in host cell vesicular transport by HIV-1 Nef and Vpu. The conservation of this activity in two independent accessory proteins suggests its importance for the spread of HIV-1 in the infected host. IMPORTANCE In this paper, we define that HIV-1 Nef and Vpu display a surprising functional overlap and affect the cell surface exposure of a previously unexpected breadth of cellular receptors. Our analyses

  1. Female house sparrows "count on" male genes: experimental evidence for MHC-dependent mate preference in birds

    Directory of Open Access Journals (Sweden)

    Biard Clotilde

    2011-02-01

    Full Text Available Abstract Background Females can potentially assess the quality of potential mates using their secondary sexual traits, and obtain "good genes" that increase offspring fitness. Another potential indirect benefit from mating preferences is genetic compatibility, which does not require extravagant or viability indicator traits. Several studies with mammals and fish indicate that the genes of the major histocompatibility complex (MHC influence olfactory cues and mating preferences, and such preferences confer genetic benefits to offspring. We investigated whether individual MHC diversity (class I influences mating preferences in house sparrows (Passer domesticus. Results Overall, we found no evidence that females preferred males with high individual MHC diversity. Yet, when we considered individual MHC allelic diversity of the females, we found that females with a low number of alleles were most attracted to males carrying a high number of MHC alleles, which might reflect a mating-up preference by allele counting. Conclusions This is the first experimental evidence for MHC-dependent mating preferences in an avian species to our knowledge. Our findings raise questions about the underlying mechanisms through which birds discriminate individual MHC diversity among conspecifics, and they suggest a novel mechanism through which mating preferences might promote the evolution of MHC polymorphisms and generate positive selection for duplicated MHC loci.

  2. New insights into the role of MHC diversity in devil facial tumour disease.

    Directory of Open Access Journals (Sweden)

    Amanda Lane

    Full Text Available BACKGROUND: Devil facial tumour disease (DFTD is a fatal contagious cancer that has decimated Tasmanian devil populations. The tumour has spread without invoking immune responses, possibly due to low levels of Major Histocompatibility Complex (MHC diversity in Tasmanian devils. Animals from a region in north-western Tasmania have lower infection rates than those in the east of the state. This area is a genetic transition zone between sub-populations, with individuals from north-western Tasmania displaying greater diversity than eastern devils at MHC genes, primarily through MHC class I gene copy number variation. Here we test the hypothesis that animals that remain healthy and tumour free show predictable differences at MHC loci compared to animals that develop the disease. METHODOLOGY/PRINCIPAL FINDINGS: We compared MHC class I sequences in 29 healthy and 22 diseased Tasmanian devils from West Pencil Pine, a population in north-western Tasmania exhibiting reduced disease impacts of DFTD. Amplified alleles were assigned to four loci, Saha-UA, Saha-UB, Saha-UC and Saha-UD based on recently obtained genomic sequence data. Copy number variation (caused by a deletion at Saha-UA was confirmed using a PCR assay. No association between the frequency of this deletion and disease status was identified. All individuals had alleles at Saha-UD, disproving theories of disease susceptibility relating to copy number variation at this locus. Genetic variation between the two sub-groups (healthy and diseased was also compared using eight MHC-linked microsatellite markers. No significant differences were identified in allele frequency, however differences were noted in the genotype frequencies of two microsatellites located near non-antigen presenting genes within the MHC. CONCLUSIONS/SIGNIFICANCE: We did not find predictable differences in MHC class I copy number variation to account for differences in susceptibility to DFTD. Genotypic data was equivocal but

  3. IRF-4-mediated CIITA transcription is blocked by KSHV encoded LANA to inhibit MHC II presentation.

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    Qiliang Cai

    2013-10-01

    Full Text Available Peptides presentation to T cells by MHC class II molecules is of importance in initiation of immune response to a pathogen. The level of MHC II expression directly influences T lymphocyte activation and is often targeted by various viruses. Kaposi's sarcoma-associated herpesvirus (KSHV encoded LANA is known to evade MHC class I peptide processing, however, the effect of LANA on MHC class II remains unclear. Here, we report that LANA down-regulates MHC II expression and presentation by inhibiting the transcription of MHC II transactivator (CIITA promoter pIII and pIV in a dose-dependent manner. Strikingly, although LANA knockdown efficiently disrupts the inhibition of CIITA transcripts from its pIII and pIV promoter region, the expression of HLA-DQβ but no other MHC II molecules was significantly restored. Moreover, we revealed that the presentation of HLA-DQβ enhanced by LANA knockdown did not help LANA-specific CD4+ T cell recognition of PEL cells, and the inhibition of CIITA by LANA is independent of IL-4 or IFN-γ signaling but dependent on the direct interaction of LANA with IRF-4 (an activator of both the pIII and pIV CIITA promoters. This interaction dramatically blocked the DNA-binding ability of IRF-4 on both pIII and pIV promoters. Thus, our data implies that LANA can evade MHC II presentation and suppress CIITA transcription to provide a unique strategy of KSHV escape from immune surveillance by cytotoxic T cells.

  4. Selector function of MHC I molecules is determined by protein plasticity

    Science.gov (United States)

    Bailey, Alistair; Dalchau, Neil; Carter, Rachel; Emmott, Stephen; Phillips, Andrew; Werner, Jörn M.; Elliott, Tim

    2015-10-01

    The selection of peptides for presentation at the surface of most nucleated cells by major histocompatibility complex class I molecules (MHC I) is crucial to the immune response in vertebrates. However, the mechanisms of the rapid selection of high affinity peptides by MHC I from amongst thousands of mostly low affinity peptides are not well understood. We developed computational systems models encoding distinct mechanistic hypotheses for two molecules, HLA-B*44:02 (B*4402) and HLA-B*44:05 (B*4405), which differ by a single residue yet lie at opposite ends of the spectrum in their intrinsic ability to select high affinity peptides. We used in vivo biochemical data to infer that a conformational intermediate of MHC I is significant for peptide selection. We used molecular dynamics simulations to show that peptide selector function correlates with protein plasticity, and confirmed this experimentally by altering the plasticity of MHC I with a single point mutation, which altered in vivo selector function in a predictable way. Finally, we investigated the mechanisms by which the co-factor tapasin influences MHC I plasticity. We propose that tapasin modulates MHC I plasticity by dynamically coupling the peptide binding region and α3 domain of MHC I allosterically, resulting in enhanced peptide selector function.

  5. MHC diversity and mate choice in the magellanic penguin, Spheniscus magellanicus.

    Science.gov (United States)

    Knafler, Gabrielle J; Clark, J Alan; Boersma, P Dee; Bouzat, Juan L

    2012-01-01

    We estimated levels of diversity at the major histocompatibility complex (MHC) class II DRß1 gene in 50 breeding pairs of the Magellanic penguin and compared those to estimates from Humboldt and Galapagos penguins. We tested for positive selection and 2 conditions required for the evolution of MHC-based disassortative mating: 1) greater MHC diversity between breeding pairs compared to random mating, and 2) associations between MHC genotype and fitness. Cloning and sequencing of the DRß1 gene showed that Magellanic penguins had higher levels of genetic variation than Galapagos and Humboldt penguins. Sequence analysis revealed 45 alleles with 3.6% average proportion of nucleotide differences, nucleotide diversity of 0.030, and observed heterozygosity of 0.770. A gene phylogeny showed 9 allelic lineages with interspersed DRß1 sequences from Humboldt and Galapagos penguins, indicating ancestral polymorphisms. d (N)/d (S) ratios revealed evidence for positive selection. Analysis of breeding pairs showed no disassortative mating preferences. Significant MHC genotype/fitness associations in females suggest, however, that selection for pathogen resistance plays a more important role than mate choice in maintaining diversity at the MHC in the Magellanic penguin. The differential effect of MHC heterozygosity on fitness between the sexes is likely associated with the relative role of hatching and fledging rates as reliable indicators of overall fitness in males and females. PMID:22952272

  6. ERAP1 structure, function and pathogenetic role in ankylosing spondylitis and other MHC-associated diseases.

    Science.gov (United States)

    Alvarez-Navarro, Carlos; López de Castro, José A

    2014-01-01

    The endoplasmic reticulum aminopeptidase 1 (ERAP1) is a multifunctional enzyme involved in the final processing of Major Histocompatibility Complex class I (MHC-I) ligands and with a significant influence in the stability and immunological properties of MHC-I proteins. ERAP1 polymorphism is associated with ankylosing spondylitis among HLA-B27-positive individuals and the altered enzymatic activity of natural variants has significant effects on the HLA-B27 peptidome, suggesting a critical pathogenetic role of peptides in this disease. Likewise, the association of ERAP1 with other MHC-I associated disorders and its epistasis with their susceptibility MHC alleles point out to a general role of the MHC-I peptidome in these diseases. The functional interaction between ERAP1 and HLA-B27 or other MHC-I molecules may be related to the processing of specific epitopes, or to a more general peptide-dependent influence on other biological features of the MHC-I proteins. In addition, from a consideration of the reported functions of ERAP1, including its involvement in angiogenesis and macrophage activation, a more complex and multi-level influence in the inflammatory and immune pathways operating in these diseases cannot be ruled out. PMID:23916068

  7. Evolution and comparative analysis of the bat MHC-I region.

    Science.gov (United States)

    Ng, Justin H J; Tachedjian, Mary; Deakin, Janine; Wynne, James W; Cui, Jie; Haring, Volker; Broz, Ivano; Chen, Honglei; Belov, Katherine; Wang, Lin-Fa; Baker, Michelle L

    2016-01-01

    Bats are natural hosts to numerous viruses and have ancient origins, having diverged from other eutherian mammals early in evolution. These characteristics place them in an important position to provide insights into the evolution of the mammalian immune system and antiviral immunity. We describe the first detailed partial map of a bat (Pteropus alecto) MHC-I region with comparative analysis of the MHC-I region and genes. The bat MHC-I region is highly condensed, yet relatively conserved in organisation, and is unusual in that MHC-I genes are present within only one of the three highly conserved class I duplication blocks. We hypothesise that MHC-I genes first originated in the β duplication block, and subsequently duplicated in a step-wise manner across the MHC-I region during mammalian evolution. Furthermore, bat MHC-I genes contain unique insertions within their peptide-binding grooves potentially affecting the peptide repertoire presented to T cells, which may have implications for the ability of bats to control infection without overt disease. PMID:26876644

  8. Expanding the diversity of unnatural cell surface sialic acids

    Energy Technology Data Exchange (ETDEWEB)

    Luchansky, Sarah J.; Goon, Scarlett; Bertozzi, Carolyn R.

    2003-10-30

    Novel chemical reactivity can be introduced onto cell surfaces through metabolic oligosaccharide engineering. This technique exploits the substrate promiscuity of cellular biosynthetic enzymes to deliver unnatural monosaccharides bearing bioorthogonal functional groups into cellular glycans. For example, derivatives of N-acetylmannosamine (ManNAc) are converted by the cellular biosynthetic machinery into the corresponding sialic acids and subsequently delivered to the cell surface in the form of sialoglycoconjugates. Analogs of N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) are also metabolized and incorporated into cell surface glycans, likely through the sialic acid and GalNAc salvage pathways, respectively. Furthermore, GlcNAc analogs can be incorporated into nucleocytoplasmic proteins in place of {beta}-O-GlcNAc residues. These pathways have been exploited to integrate unique electrophiles such as ketones and azides into the target glycoconjugate class. These functional groups can be further elaborated in a chemoselective fashion by condensation with hydrazides and by Staudinger ligation, respectively, thereby introducing detectable probes onto the cell. In conclusion, sialic acid derivatives are efficient vehicles for delivery of bulky functional groups to cell surfaces and masking of their hydroxyl groups improves their cellular uptake and utilization. Furthermore, the successful introduction of photoactivatable aryl azides into cell surface glycans opens up new avenues for studying sialic acid-binding proteins and elucidating the role of sialic acid in essential processes such as signaling and cell adhesion.

  9. Quantitative analysis of mouse urine volatiles: in search of MHC-dependent differences.

    Directory of Open Access Journals (Sweden)

    Frank Röck

    Full Text Available Genes of the major histocompatibility complex (MHC, which play a critical role in immune recognition, influence mating preference and other social behaviors in mice. Training experiments using urine scent from mice differing only in the MHC complex, from MHC class I mutants or from knock-out mice lacking functional MHC class I molecules (beta2m-deficient, suggest that these behavioral effects are mediated by differences in MHC-dependent volatile components. In search for the physical basis of these behavioral studies, we have conducted a comparison of urinary volatiles in three sub-strains of C57BL/6 mice, a beta2m-deficient mutant lacking functional MHC class I expression and two unrelated inbred strains, using the technique of sorptive extraction with polydimethylsiloxan and subsequent analysis by gas chromatography/mass spectrometry. We show (i that qualitative differences occur between different inbred strains but not in mice with the C57BL/6 background, (ii that the individual variability in abundance in the same mouse strain is strongly component-dependent, (iii that C57BL/6 sub-strains obtained from different provenance show a higher fraction of quantitative differences than a sub-strain and its beta2m-mutant obtained from the same source and (iv that comparison of the spectra of beta2m mice and the corresponding wild type reveals no qualitative differences in close to 200 major and minor components and only minimal differences in a few substances from an ensemble of 69 selected for quantitative analysis. Our data suggest that odor is shaped by ontogenetic, environmental and genetic factors, and the gestalt of this scent may identify a mouse on the individual and population level; but, within the limits of the ensemble of components analysed, the results do not support the notion that functional MHC class I molecules influence the urinary volatile composition.

  10. MHC-like molecules in some nonmammalian vertebrates can be detected by some cross-reactive xenoantisera

    DEFF Research Database (Denmark)

    Kaufman, J; Skjoedt, K; Salomonsen, J;

    1990-01-01

    in the contact regions between the chains. These latter antibodies recognized biosynthetic intermediates and also a variety of unusual cell surface MHC-like molecules present in reptile and amphibian, but absent in the mammal and chicken cells tested. These included E homodimers whose relationship to chicken B......-G molecules is unknown. 5) MHC-like molecules were identified in a bird, three reptiles, and two amphibians, but no molecules with the expected properties were found with these reagents in any of the fish tested. Udgivelsesdato: 1990-Mar-15...

  11. MHC II expression in the CNS after long-term demyelination

    Energy Technology Data Exchange (ETDEWEB)

    Cannella, B.; Aquino, D.A.; Raine, C.S.

    1995-07-01

    The ability of chronically demyelinated central nervous system (CNS) tissue to express major histocompatibility complex (MHC) class II molecules has been measured in mouse spinal cord cultures exposed for 1 and 3 weeks to demyelinating anti-white matter (WM) serum. From previous studies, It was known that after 3 weeks of demyelination in vitro, such cultures are incapable of remyelination. In the present report, MHC II levels were evaluated by immunocytochemistry and by Western and Northern blots. The results have shown that after both 1 and 3 weeks of exposure to myelinotoxic anti-WM serum, the cultures retained the ability to express MHC II and this could be further upregulated by incubation with interferon {gamma} (IFN{gamma}). Control groups showed increased expression of MHC II with age. By immunocytochemistry, all groups of cultures expressed high levels of MHC II and all groups showed upregulation after IFN{gamma} treatment. Anti-WM-treated cultures demonstrated slightly higher levels of MHC II than controls. Morphologically, the MHC II expression was associated with the surface of astrocytes. Semiquantitative analysis by Western blotting confirmed the increase in class II MHC expression in the long-term treated cultures after IFN{gamma} exposure, revealing no differences between anti-WM-treated and complement-treated cultures. This was also supported by Northern blotting which showed similar mRNA levels in both groups. These findings suggest that long-term demyelinated CNS tissue still possesses the ability to interact with CD4{sup +} T cells, observations of significance to the expansion of the chronic multiple sclerosis lesion. 50 refs., 6 figs., 2 tabs.

  12. Exhaustive proteome mining for functional MHC-I ligands.

    Science.gov (United States)

    Koch, Christian P; Perna, Anna M; Weissmüller, Sabrina; Bauer, Stefanie; Pillong, Max; Baleeiro, Renato B; Reutlinger, Michael; Folkers, Gerd; Walden, Peter; Wrede, Paul; Hiss, Jan A; Waibler, Zoe; Schneider, Gisbert

    2013-09-20

    We present the development and application of a new machine-learning approach to exhaustively and reliably identify major histocompatibility complex class I (MHC-I) ligands among all 20(8) octapeptides and in genome-derived proteomes of Mus musculus , influenza A H3N8, and vesicular stomatitis virus (VSV). Focusing on murine H-2K(b), we identified potent octapeptides exhibiting direct MHC-I binding and stabilization on the surface of TAP-deficient RMA-S cells. Computationally identified VSV-derived peptides induced CD8(+) T-cell proliferation after VSV-infection of mice. The study demonstrates that high-level machine-learning models provide a unique access to rationally designed peptides and a promising approach toward "reverse vaccinology". PMID:23772559

  13. MHC I Stabilizing Potential of Computer-Designed Octapeptides

    Directory of Open Access Journals (Sweden)

    Joanna M. Wisniewska

    2010-01-01

    Full Text Available Experimental results are presented for 180 in silico designed octapeptide sequences and their stabilizing effects on the major histocompatibility class I molecule H-2Kb. Peptide sequence design was accomplished by a combination of an ant colony optimization algorithm with artificial neural network classifiers. Experimental tests yielded nine H-2Kb stabilizing and 171 nonstabilizing peptides. 28 among the nonstabilizing octapeptides contain canonical motif residues known to be favorable for MHC I stabilization. For characterization of the area covered by stabilizing and non-stabilizing octapeptides in sequence space, we visualized the distribution of 100,603 octapeptides using a self-organizing map. The experimental results present evidence that the canonical sequence motives of the SYFPEITHI database on their own are insufficient for predicting MHC I protein stabilization.

  14. Major histocompatibility class I molecules present Urtica dioica agglutinin, a superantigen of vegetal origin, to T lymphocytes.

    Science.gov (United States)

    Rovira, P; Buckle, M; Abastado, J P; Peumans, W J; Truffa-Bachi, P

    1999-05-01

    The Urtica dioica agglutinin (UDA) shares with the superantigens the property of activating T cell subsets bearing particular Vbeta segments of the TCR. However, UDA is a lectin capable of binding to many glycoproteins on cell membranes. The implication of MHC versus other glycoproteins in UDA presentation was presently studied. Using mutant mice lacking MHC class I (MHC-I), MHC class II (MHC-II) or both MHC antigens, we provided evidence that MHC-I and MHC-II molecules serve as UDA receptors. Presentation by either one of these molecules ensured similar T cell responses and co-stimulatory signals were mandatory for optimal T cell activation and proliferation both in MHC-I and MHC-II contexts. Remarkably, in the absence of MHC molecules, UDA could not be efficiently presented to T cells by other glycosylated proteins. Surface plasmon resonance studies were used to confirm the binding of UDA to MHC-I molecules using a fusion protein consisting of MHC-I domains and beta2-microglobulin. The results indicated that the interaction between UDA and MHC-I molecules implicated lectin-binding site(s) of UDA. Taken together, our data demonstrate that, in addition to MHC-II antigens, MHC-I molecules serve as an alternative ligand for UDA.

  15. Association of MHC region SNPs with irritant susceptibility in healthcare workers.

    Science.gov (United States)

    Yucesoy, Berran; Talzhanov, Yerkebulan; Michael Barmada, M; Johnson, Victor J; Kashon, Michael L; Baron, Elma; Wilson, Nevin W; Frye, Bonnie; Wang, Wei; Fluharty, Kara; Gharib, Rola; Meade, Jean; Germolec, Dori; Luster, Michael I; Nedorost, Susan

    2016-09-01

    Irritant contact dermatitis is the most common work-related skin disease, especially affecting workers in "wet-work" occupations. This study was conducted to investigate the association between single nucleotide polymorphisms (SNPs) within the major histocompatibility complex (MHC) and skin irritant response in a group of healthcare workers. 585 volunteer healthcare workers were genotyped for MHC SNPs and patch tested with three different irritants: sodium lauryl sulfate (SLS), sodium hydroxide (NaOH) and benzalkonium chloride (BKC). Genotyping was performed using Illumina Goldengate MHC panels. A number of SNPs within the MHC Class I (OR2B3, TRIM31, TRIM10, TRIM40 and IER3), Class II (HLA-DPA1, HLA-DPB1) and Class III (C2) genes were associated (p genes, with a potential impact on gene regulation. In addition, SNPs in PSMB9 (rs10046277 and ITPR3 (rs499384) were associated with hand dermatitis. The results are of interest as they demonstrate that genetic variations in inflammation-related genes within the MHC can influence chemical-induced skin irritation and may explain the connection between inflamed skin and propensity to subsequent allergic contact sensitization. PMID:27258892

  16. MHC associations with clinical and autoantibody manifestations in European SLE.

    Science.gov (United States)

    Morris, D L; Fernando, M M A; Taylor, K E; Chung, S A; Nititham, J; Alarcón-Riquelme, M E; Barcellos, L F; Behrens, T W; Cotsapas, C; Gaffney, P M; Graham, R R; Pons-Estel, B A; Gregersen, P K; Harley, J B; Hauser, S L; Hom, G; Langefeld, C D; Noble, J A; Rioux, J D; Seldin, M F; Vyse, T J; Criswell, L A

    2014-04-01

    Systemic lupus erythematosus (SLE) is a clinically heterogeneous disease affecting multiple organ systems and characterized by autoantibody formation to nuclear components. Although genetic variation within the major histocompatibility complex (MHC) is associated with SLE, its role in the development of clinical manifestations and autoantibody production is not well defined. We conducted a meta-analysis of four independent European SLE case collections for associations between SLE sub-phenotypes and MHC single-nucleotide polymorphism genotypes, human leukocyte antigen (HLA) alleles and variant HLA amino acids. Of the 11 American College of Rheumatology criteria and 7 autoantibody sub-phenotypes examined, anti-Ro/SSA and anti-La/SSB antibody subsets exhibited the highest number and most statistically significant associations. HLA-DRB1*03:01 was significantly associated with both sub-phenotypes. We found evidence of associations independent of MHC class II variants in the anti-Ro subset alone. Conditional analyses showed that anti-Ro and anti-La subsets are independently associated with HLA-DRB1*0301, and that the HLA-DRB1*03:01 association with SLE is largely but not completely driven by the association of this allele with these sub-phenotypes. Our results provide strong evidence for a multilevel risk model for HLA-DRB1*03:01 in SLE, where the association with anti-Ro and anti-La antibody-positive SLE is much stronger than SLE without these autoantibodies.

  17. MHC adaptive divergence between closely related and sympatric African cichlids.

    Directory of Open Access Journals (Sweden)

    Jonatan Blais

    Full Text Available BACKGROUND: The haplochromine cichlid species assemblages of Lake Malawi and Victoria represent some of the most important study systems in evolutionary biology. Identifying adaptive divergence between closely-related species can provide important insights into the processes that may have contributed to these spectacular radiations. Here, we studied a pair of sympatric Lake Malawi species, Pseudotropheus fainzilberi and P. emmiltos, whose reproductive isolation depends on olfactory communication. We tested the hypothesis that these species have undergone divergent selection at MHC class II genes, which are known to contribute to olfactory-based mate choice in other taxa. METHODOLOGY/PRINCIPAL FINDINGS: Divergent selection on functional alleles was inferred from the higher genetic divergence at putative antigen binding sites (ABS amino acid sequences than at putatively neutrally evolving sites at intron 1, exon 2 synonymous sequences and exon 2 amino acid residues outside the putative ABS. In addition, sympatric populations of these fish species differed significantly in communities of eukaryotic parasites. CONCLUSIONS/SIGNIFICANCE: We propose that local host-parasite coevolutionary dynamics may have driven adaptive divergence in MHC alleles, influencing odor-mediated mate choice and leading to reproductive isolation. These results provide the first evidence for a novel mechanism of adaptive speciation and the first evidence of adaptive divergence at the MHC in closely related African cichlid fishes.

  18. The cell surface of Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    1984-01-01

    Full Text Available The cell surface of trypanosomatids is formed by the plasma membrane and a layer of sub-pellicular microtubules which are connected to the plasma membrane. The plasma membrane is composed by proteins, lipids and carbohydrates which form the glycocalix. In this paper we will review briefly aspects related to the organization of the cell surface of Trypanosoma cruzi.

  19. Refinement of the MHC risk map in a scandinavian primary sclerosing cholangitis population.

    Directory of Open Access Journals (Sweden)

    Sigrid Næss

    Full Text Available Genetic variants within the major histocompatibility complex (MHC represent the strongest genetic susceptibility factors for primary sclerosing cholangitis (PSC. Identifying the causal variants within this genetic complex represents a major challenge due to strong linkage disequilibrium and an overall high physical density of candidate variants. We aimed to refine the MHC association in a geographically restricted PSC patient panel.A total of 365 PSC cases and 368 healthy controls of Scandinavian ancestry were included in the study. We incorporated data from HLA typing (HLA-A, -B, -C, -DRB3, -DRB1, -DQB1 and single nucleotide polymorphisms across the MHC (n = 18,644; genotyped and imputed alongside previously suggested PSC risk determinants in the MHC, i.e. amino acid variation of DRβ, a MICA microsatellite polymorphism and HLA-C and HLA-B according to their ligand properties for killer immunoglobulin-like receptors. Breakdowns of the association signal by unconditional and conditional logistic regression analyses demarcated multiple PSC associated MHC haplotypes, and for eight of these classical HLA class I and II alleles represented the strongest association. A novel independent risk locus was detected near NOTCH4 in the HLA class III region, tagged by rs116212904 (odds ratio [95% confidence interval] = 2.32 [1.80, 3.00], P = 1.35×10-11.Our study shows that classical HLA class I and II alleles, predominantly at HLA-B and HLA-DRB1, are the main risk factors for PSC in the MHC. In addition, the present assessments demonstrated for the first time an association near NOTCH4 in the HLA class III region.

  20. Refinement of the MHC Risk Map in a Scandinavian Primary Sclerosing Cholangitis Population

    Science.gov (United States)

    Næss, Sigrid; Lie, Benedicte A.; Melum, Espen; Olsson, Marita; Hov, Johannes R.; Croucher, Peter J. P.; Hampe, Jochen; Thorsby, Erik; Bergquist, Annika; Traherne, James A.; Schrumpf, Erik; Boberg, Kirsten Muri; Schreiber, Stefan; Franke, Andre; Karlsen, Tom H.

    2014-01-01

    Background Genetic variants within the major histocompatibility complex (MHC) represent the strongest genetic susceptibility factors for primary sclerosing cholangitis (PSC). Identifying the causal variants within this genetic complex represents a major challenge due to strong linkage disequilibrium and an overall high physical density of candidate variants. We aimed to refine the MHC association in a geographically restricted PSC patient panel. Methodology/Principal Findings A total of 365 PSC cases and 368 healthy controls of Scandinavian ancestry were included in the study. We incorporated data from HLA typing (HLA-A, -B, -C, -DRB3, -DRB1, -DQB1) and single nucleotide polymorphisms across the MHC (n = 18,644; genotyped and imputed) alongside previously suggested PSC risk determinants in the MHC, i.e. amino acid variation of DRβ, a MICA microsatellite polymorphism and HLA-C and HLA-B according to their ligand properties for killer immunoglobulin-like receptors. Breakdowns of the association signal by unconditional and conditional logistic regression analyses demarcated multiple PSC associated MHC haplotypes, and for eight of these classical HLA class I and II alleles represented the strongest association. A novel independent risk locus was detected near NOTCH4 in the HLA class III region, tagged by rs116212904 (odds ratio [95% confidence interval] = 2.32 [1.80, 3.00], P = 1.35×10−11). Conclusions/Significance Our study shows that classical HLA class I and II alleles, predominantly at HLA-B and HLA-DRB1, are the main risk factors for PSC in the MHC. In addition, the present assessments demonstrated for the first time an association near NOTCH4 in the HLA class III region. PMID:25521205

  1. Expression of EPHRIN-A1, SCINDERIN and MHC class I molecules in head and neck cancers and relationship with the prognostic value of intratumoral CD8+ T cells

    International Nuclear Information System (INIS)

    Our group has previously shown that EPHRIN-A1 and SCINDERIN expression by tumor cells rendered them resistant to cytotoxic T lymphocyte-mediated lysis. Whereas the prognostic value of EPHRIN-A1 expression in cancer has already been studied, the role of SCINDERIN presence remains to be established. In the present work, we investigated the prognosis value of EPHRIN-A1 and SCINDERIN expression in head and neck carcinomas. In addition, we monitored the HLA-class I expression by tumor cells and the presence of tumor-infiltrating CD8+ T cells to evaluate a putative correlation between these factors and the survival prognosis by themselves or related to EPHRIN-A1 and SCINDERIN expression. Tumor tissue sections of 83 patients with head and neck cancer were assessed by immunohistochemistry for the expression of EPHRIN-A1, SCINDERIN, HLA class I molecules and the presence of CD8+ T cells. No significant prognosis value could be attributed to these factors independently, despite a tendency of association between EPHRIN-A1 and a worse clinical outcome. No prognostic value could be observed when CD8+ T cell tumor infiltration was analyzed combined with EPHRIN-A1, SCINDERIN or HLA class I expression. These results highlight that molecules involved in cancer cell resistance to cytotoxic T lymphocytes by themselves are not a sufficient criteria for prognosis determination in cancer patients. Other intrinsic or tumor microenvironmental features should be considered in prognostic evaluation

  2. NETMHCSTAB - predicting stability of peptide-MHC-I complexes; impacts for cytotoxic T lymphocyte epitope discovery

    DEFF Research Database (Denmark)

    Jørgensen, Kasper W.; Rasmussen, Michael; Buus, Søren;

    2013-01-01

    Major histocompatibility complex class I (MHC-I) molecules play an essential role in the cellular immune response, presenting peptides to cytotoxic T lymphocytes (CTLs) allowing the immune system to scrutinize ongoing intracellular production of proteins. In the early 1990s, immunogenicity...

  3. The P9 pocket of HLA-DQ2 (non-Aspbeta57) has no particular preference for negatively charged anchor residues found in other type 1 diabetes-predisposing non-Aspbeta57 MHC class II molecules

    DEFF Research Database (Denmark)

    Quarsten, H; Paulsen, G; Johansen, B H;

    1998-01-01

    -predisposing class II molecules. The molecular explanation for such a phenomenon could be that class II beta chains with Aspbeta57 form a salt bridge between Aspbeta57 and a conserved Arg of the a chain, whereas in non-Aspbeta57 molecules the Arg is unopposed and free to interact with negatively charged P9 peptide...... anchor residues. We have investigated the specificity of the P9 pocket of the type 1 diabetes-associated DQ2 molecule and in particular examined for charge effects at this anchor position. Different approaches were undertaken. We analyzed binding of a high-affinity binding ligand and P9-substituted...... variants of this peptide, and we analyzed the binding of a set of synthetic random peptide libraries. The binding analyses were performed with wild-type DQ2 and a mutated DQ2 with Ala at beta57 substituted with Asp. Our results indicate that the wild-type DQ2 (non-Aspbeta57) prefers large hydrophobic...

  4. MHC Region and Its Related Disease Study

    DEFF Research Database (Denmark)

    Cao, Hongzhi

    The major histocompatibility complex (MHC) is one of the most gene dense regions in the human genome and many disorders, including primary immune deficiencies, autoimmune conditions, infections, cancers and mental disorder have been found to be associated with this region. However, due to a high...... detection as well as HLA gene typing and large structural variation detection using optical mapping technic, to provide comprehensive and accurate information of the MHC region and apply them into disease causal mutation’s fine-mapping....

  5. Functions of proteoglycans at the cell surface

    DEFF Research Database (Denmark)

    Höök, M; Woods, A; Johansson, S;

    1986-01-01

    Proteoglycans (primarily heparan sulphate proteoglycans) are found at the surface of most adherent eukaryotic cells. Earlier studies suggest that these molecules can be associated with the cell surface principally by two different mechanisms. Proteoglycans may occur as membrane-intercalated glyco......Proteoglycans (primarily heparan sulphate proteoglycans) are found at the surface of most adherent eukaryotic cells. Earlier studies suggest that these molecules can be associated with the cell surface principally by two different mechanisms. Proteoglycans may occur as membrane......-intercalated glycoproteins, where the core protein of the proteoglycan is anchored in the lipid interior of the plasma membrane, or they may be bound via the polysaccharide components of the molecule to specific anchoring proteins present at the cell surface. A number of functions have been proposed for cell surface...

  6. Derivation of an amino acid similarity matrix for peptide:MHC binding and its application as a Bayesian prior

    Directory of Open Access Journals (Sweden)

    Sette Alessandro

    2009-11-01

    Full Text Available Abstract Background Experts in peptide:MHC binding studies are often able to estimate the impact of a single residue substitution based on a heuristic understanding of amino acid similarity in an experimental context. Our aim is to quantify this measure of similarity to improve peptide:MHC binding prediction methods. This should help compensate for holes and bias in the sequence space coverage of existing peptide binding datasets. Results Here, a novel amino acid similarity matrix (PMBEC is directly derived from the binding affinity data of combinatorial peptide mixtures. Like BLOSUM62, this matrix captures well-known physicochemical properties of amino acid residues. However, PMBEC differs markedly from existing matrices in cases where residue substitution involves a reversal of electrostatic charge. To demonstrate its usefulness, we have developed a new peptide:MHC class I binding prediction method, using the matrix as a Bayesian prior. We show that the new method can compensate for missing information on specific residues in the training data. We also carried out a large-scale benchmark, and its results indicate that prediction performance of the new method is comparable to that of the best neural network based approaches for peptide:MHC class I binding. Conclusion A novel amino acid similarity matrix has been derived for peptide:MHC binding interactions. One prominent feature of the matrix is that it disfavors substitution of residues with opposite charges. Given that the matrix was derived from experimentally determined peptide:MHC binding affinity measurements, this feature is likely shared by all peptide:protein interactions. In addition, we have demonstrated the usefulness of the matrix as a Bayesian prior in an improved scoring-matrix based peptide:MHC class I prediction method. A software implementation of the method is available at: http://www.mhc-pathway.net/smmpmbec.

  7. MHC-I and PirB Upregulation in the Central and Peripheral Nervous System following Sciatic Nerve Injury

    Science.gov (United States)

    Bombeiro, André Luis; Thomé, Rodolfo; Oliveira Nunes, Sérgio Luiz; Monteiro Moreira, Bárbara; Verinaud, Liana; de Oliveira, Alexandre Leite Rodrigues

    2016-01-01

    Major histocompatibility complex class one (MHC-I) antigen-presenting molecules participate in central nervous system (CNS) synaptic plasticity, as does the paired immunoglobulin-like receptor B (PirB), an MHC-I ligand that can inhibit immune-cells and bind to myelin axon growth inhibitors. Based on the dual roles of both molecules in the immune and nervous systems, we evaluated their expression in the central and peripheral nervous system (PNS) following sciatic nerve injury in mice. Increased PirB and MHC-I protein and gene expression is present in the spinal cord one week after nerve transection, PirB being mostly expressed in the neuropile region. In the crushed nerve, MHC-I protein levels increased 2 weeks after lesion (wal) and progressively decreased over the next eight weeks. The same kinetics were observed for infiltrating cytotoxic T lymphocytes (CTLs) but not for PirB expression, which continuously increased. Both MHC-I and PirB were found in macrophages and Schwann cells but rarely in axons. Interestingly, at 8 wal, PirB was mainly restricted to the myelin sheath. Our findings reinforce the participation of MHC-I and PirB in CNS plasticity events. In contrast, opposing expression levels of these molecules were found in the PNS, so that MHC-I and PirB seem to be mostly implicated in antigen presentation to CTLs and axon myelination, respectively. PMID:27551751

  8. MHC-I and PirB Upregulation in the Central and Peripheral Nervous System following Sciatic Nerve Injury.

    Science.gov (United States)

    Bombeiro, André Luis; Thomé, Rodolfo; Oliveira Nunes, Sérgio Luiz; Monteiro Moreira, Bárbara; Verinaud, Liana; Oliveira, Alexandre Leite Rodrigues de

    2016-01-01

    Major histocompatibility complex class one (MHC-I) antigen-presenting molecules participate in central nervous system (CNS) synaptic plasticity, as does the paired immunoglobulin-like receptor B (PirB), an MHC-I ligand that can inhibit immune-cells and bind to myelin axon growth inhibitors. Based on the dual roles of both molecules in the immune and nervous systems, we evaluated their expression in the central and peripheral nervous system (PNS) following sciatic nerve injury in mice. Increased PirB and MHC-I protein and gene expression is present in the spinal cord one week after nerve transection, PirB being mostly expressed in the neuropile region. In the crushed nerve, MHC-I protein levels increased 2 weeks after lesion (wal) and progressively decreased over the next eight weeks. The same kinetics were observed for infiltrating cytotoxic T lymphocytes (CTLs) but not for PirB expression, which continuously increased. Both MHC-I and PirB were found in macrophages and Schwann cells but rarely in axons. Interestingly, at 8 wal, PirB was mainly restricted to the myelin sheath. Our findings reinforce the participation of MHC-I and PirB in CNS plasticity events. In contrast, opposing expression levels of these molecules were found in the PNS, so that MHC-I and PirB seem to be mostly implicated in antigen presentation to CTLs and axon myelination, respectively. PMID:27551751

  9. Cell-surface remodelling during mammalian erythropoiesis.

    Science.gov (United States)

    Wraith, D C; Chesterton, C J

    1982-10-15

    Current evidence suggests that the major cell-surface modification occurring during mammalian erythropoiesis could be generated by two separate mechanisms: either selective loss of membrane proteins during enucleation or endocytosis at the subsequent reticulocyte and erythrocyte stages. The former idea was tested by collecting developing rabbit erythroid cells before and after the enucleation step and comparing their cell-surface protein composition via radiolabelling and electrophoresis. Few changes were observed. Our data thus lend support to the endocytosis mechanism.

  10. Low MHC variation in the endangered Galápagos penguin (Spheniscus mendiculus).

    Science.gov (United States)

    Bollmer, Jennifer L; Vargas, F Hernán; Parker, Patricia G

    2007-07-01

    The major histocompatibility complex (MHC) is one of the most polymorphic regions of the genome, likely due to balancing selection acting to maintain alleles over time. Lack of MHC variability has been attributed to factors such as genetic drift in small populations and relaxed selection pressure. The Galápagos penguin (Spheniscus mendiculus), endemic to the Galápagos Islands, is the only penguin that occurs on the equator. It relies upon cold, nutrient-rich upwellings and experiences severe population declines when ocean temperatures rise during El Niño events. These bottlenecks, occurring in an already small population, have likely resulted in reduced genetic diversity in this species. In this study, we used MHC class II exon 2 sequence data from a DRB1-like gene to characterize the amount of genetic variation at the MHC in 30 Galápagos penguins, as well as one Magellanic penguin (S. magellanicus) and two king penguins (Aptenodytes patagonicus), and compared it to that in five other penguin species for which published data exist. We found that the Galápagos penguin had the lowest MHC diversity (as measured by number of polymorphic sites and average divergence among alleles) of the eight penguin species studied. A phylogenetic analysis showed that Galápagos penguin MHC sequences are most closely related to Humboldt penguin (Spheniscus humboldti) sequences, its putative sister species based on other loci. An excess of non-synonymous mutations and a pattern of trans-specific evolution in the neighbor-joining tree suggest that selection is acting on the penguin MHC. PMID:17457582

  11. MHC/Peptide-Specific Interaction of the Humoral Immune System: A New Category of Antibodies.

    Science.gov (United States)

    Held, Gerhard; Luescher, Immanuel F; Neumann, Frank; Papaioannou, Chrysostomos; Schirrmann, Thomas; Sester, Martina; Smola, Sigrun; Pfreundschuh, Michael

    2015-11-01

    Abs bind to unprocessed Ags, whereas cytotoxic CD8(+) T cells recognize peptides derived from endogenously processed Ags presented in the context of class I MHC complexes. We screened, by ELISA, human sera for Abs reacting specifically with the influenza matrix protein (IMP)-derived peptide(58-66) displayed by HLA-A*0201 complexes. Among 653 healthy volunteers, blood donors, and women on delivery, high-titered HLA-A*0201/IMP(58-66) complex-specific IgG Abs were detected in 11 females with a history of pregnancies and in 1 male, all HLA-A*0201(-). These Abs had the same specificity as HLA-A*0201/IMP(58-66)-specific cytotoxic T cells and bound neither to HLA-A*0201 nor the peptide alone. No such Abs were detected in HLA-A*0201(+) volunteers. These Abs were not cross-reactive to other self-MHC class I alleles displaying IMP(58-66), but bound to MHC class I complexes of an HLA nonidentical offspring. HLA-A*0201/IMP(58-66) Abs were also detected in the cord blood of newborns, indicating that HLA-A*0201/IMP(58-66) Abs are produced in HLA-A*0201(-) mothers and enter the fetal blood system. That Abs can bind to peptides derived from endogenous Ags presented by MHC complexes opens new perspectives on interactions between the cellular and humoral immune system. PMID:26416277

  12. Description and prediction of peptide-MHC binding: the 'human MHC project'

    DEFF Research Database (Denmark)

    Buus, S

    1999-01-01

    MHC molecules are crucially involved in controlling the specific immune system. They are highly polymorphic receptors sampling peptides from the cellular environment and presenting these peptides for scrutiny by immune cells. Recent advances in combinatorial peptide chemistry have improved the de...... the description and prediction of peptide-MHC binding. It is envisioned that a complete mapping of human immune reactivities will be possible....

  13. Class I (H-2Kb) gene transfection reduces susceptibility of YAC-1 lymphoma targets to natural killer cells.

    Science.gov (United States)

    Carlow, D A; Payne, U; Hozumi, N; Roder, J C; Czitrom, A A

    1990-04-01

    A "hybrid gene" (MTKb) comprised of the human metallothionein IIA promoter ligated to the genomic sequence of the major histocompatibility complex class I (H-2Kb) gene was subcloned into the expression vector pSV2neo and transfected into the natural killer (NK) cell-sensitive YAC-1 lymphoma. The Kb gene product was readily detectable on the cell surface of G418-resistant transfectants using both Kb-specific monoclonal antibodies and H-2b-specific cytolytic T cells. Unlike control pSV2neo transfectants, MTKb-pSV2neo transfectants were relatively resistant to lysis by NK cells from H-2a, H-2b, H-2k or H-2 (a x b)F1 haplotype mice. These data strongly suggest that the effects of MHC expression on susceptibility to NK cells can be mediated by a single and well-defined class I molecule, Kb.

  14. SYK regulates macrophage MHC-II expression via activation of autophagy in response to oxidized LDL

    Science.gov (United States)

    Choi, Soo-Ho; Gonen, Ayelet; Diehl, Cody J; Kim, Jungsu; Almazan, Felicidad; Witztum, Joseph L; Miller, Yury I

    2015-01-01

    Adaptive immunity, which plays an important role in the development of atherosclerosis, is mediated by major histocompatibility complex (MHC)-dependent antigen presentation. In atherosclerotic lesions, macrophages constitute an important class of antigen-presenting cells that activate adaptive immune responses to oxidized low-density lipoprotein (OxLDL). It has been reported that autophagy regulates adaptive immune responses by enhancing antigen presentation to MHC class II (MHC-II). In a previous study, we have demonstrated that SYK (spleen tyrosine kinase) regulates generation of reactive oxygen species (ROS) and activation of MAPK8/JNK1 in macrophages. Because ROS and MAPK8 are known to regulate autophagy, in this study we investigated the role of SYK in autophagy, MHC-II expression and adaptive immune response to OxLDL. We demonstrate that OxLDL induces autophagosome formation, MHC-II expression, and phosphorylation of SYK in macrophages. Gene knockout and pharmacological inhibitors of NOX2 and MAPK8 reduced OxLDL-induced autophagy. Using bone marrow-derived macrophages isolated from wild-type and myeloid-specific SYK knockout mice, we demonstrate that SYK regulates OxLDL-induced ROS generation, MAPK8 activation, BECN1-BCL2 dissociation, autophagosome formation and presentation of OxLDL-derived antigens to CD4+ T cells. ldlr−/− syk−/− mice fed a high-fat diet produced lower levels of IgG to malondialdehyde (MDA)-LDL, malondialdehyde-acetaldehyde (MAA)-LDL, and OxLDL compared to ldlr−/− mice. These results provide new insights into the mechanisms by which SYK regulates MHC-II expression via autophagy in macrophages and may contribute to regulation of adaptive immune responses in atherosclerosis. PMID:25946330

  15. SYK regulates macrophage MHC-II expression via activation of autophagy in response to oxidized LDL.

    Science.gov (United States)

    Choi, Soo-Ho; Gonen, Ayelet; Diehl, Cody J; Kim, Jungsu; Almazan, Felicidad; Witztum, Joseph L; Miller, Yury I

    2015-01-01

    Adaptive immunity, which plays an important role in the development of atherosclerosis, is mediated by major histocompatibility complex (MHC)-dependent antigen presentation. In atherosclerotic lesions, macrophages constitute an important class of antigen-presenting cells that activate adaptive immune responses to oxidized low-density lipoprotein (OxLDL). It has been reported that autophagy regulates adaptive immune responses by enhancing antigen presentation to MHC class II (MHC-II). In a previous study, we have demonstrated that SYK (spleen tyrosine kinase) regulates generation of reactive oxygen species (ROS) and activation of MAPK8/JNK1 in macrophages. Because ROS and MAPK8 are known to regulate autophagy, in this study we investigated the role of SYK in autophagy, MHC-II expression and adaptive immune response to OxLDL. We demonstrate that OxLDL induces autophagosome formation, MHC-II expression, and phosphorylation of SYK in macrophages. Gene knockout and pharmacological inhibitors of NOX2 and MAPK8 reduced OxLDL-induced autophagy. Using bone marrow-derived macrophages isolated from wild-type and myeloid-specific SYK knockout mice, we demonstrate that SYK regulates OxLDL-induced ROS generation, MAPK8 activation, BECN1-BCL2 dissociation, autophagosome formation and presentation of OxLDL-derived antigens to CD4(+) T cells. ldlr(-/-) syk(-/-) mice fed a high-fat diet produced lower levels of IgG to malondialdehyde (MDA)-LDL, malondialdehyde-acetaldehyde (MAA)-LDL, and OxLDL compared to ldlr(-/-) mice. These results provide new insights into the mechanisms by which SYK regulates MHC-II expression via autophagy in macrophages and may contribute to regulation of adaptive immune responses in atherosclerosis.

  16. Natural selection of the major histocompatibility complex (Mhc) in Hawaiian honeycreepers (Drepanidinae)

    Science.gov (United States)

    Jarvi, S.I.; Tarr, C.L.; Mcintosh, C.E.; Atkinson, C.T.; Fleischer, R.C.

    2004-01-01

    The native Hawaiian honeycreepers represent a classic example of adaptive radiation and speciation, but currently face one the highest extinction rates in the world. Although multiple factors have likely influenced the fate of Hawaiian birds, the relatively recent introduction of avian malaria is thought to be a major factor limiting honeycreeper distribution and abundance. We have initiated genetic analyses of class II ?? chain Mhc genes in four species of honeycreepers using methods that eliminate the possibility of sequencing mosaic variants formed by cloning heteroduplexed polymerase chain reaction products. Phylogenetic analyses group the honeycreeper Mhc sequences into two distinct clusters. Variation within one cluster is high, with dN > d S and levels of diversity similar to other studies of Mhc (B system) genes in birds. The second cluster is nearly invariant and includes sequences from honeycreepers (Fringillidae), a sparrow (Emberizidae) and a blackbird (Emberizidae). This highly conserved cluster appears reminiscent of the independently segregating Rfp-Y system of genes defined in chickens. The notion that balancing selection operates at the Mhc in the honeycreepers is supported by transpecies polymorphism and strikingly high dN/dS ratios at codons putatively involved in peptide interaction. Mitochondrial DNA control region sequences were invariant in the i'iwi, but were highly variable in the 'amakihi. By contrast, levels of variability of class II ?? chain Mhc sequence codons that are hypothesized to be directly involved in peptide interactions appear comparable between i'iwi and 'amakihi. In the i'iwi, natural selection may have maintained variation within the Mhc, even in the face of what appears to a genetic bottleneck.

  17. The MHC motif viewer: a visualization tool for MHC binding motifs

    DEFF Research Database (Denmark)

    Rapin, Nicolas; Hoof, Ilka; Lund, Ole;

    2010-01-01

    In vertebrates, the onset of cellular immune reactions is controlled by presentation of peptides in complex with major histocompatibility complex (MHC) molecules to T cell receptors. In humans, MHCs are called human leukocyte antigens (HLAs). Different MHC molecules present different subsets of...... peptides, and knowledge of their binding specificities is important for understanding differences in the immune response between individuals. Algorithms predicting which peptides bind a given MHC molecule have recently been developed with high prediction accuracy. The utility of these algorithms is...... binding motif for each MHC molecule is predicted using state-of-the-art, pan-specific peptide-MHC binding-prediction methods, and is visualized as a sequence logo, in a format that allows for a comprehensive interpretation of binding motif anchor positions and amino acid preferences....

  18. Shared fine specificity between T-cell receptors and an antibody recognizing a peptide/major histocompatibility class I complex

    DEFF Research Database (Denmark)

    Stryhn, A; Andersen, P S; Pedersen, L O;

    1996-01-01

    Cytotoxic T cells recognize mosaic structures consisting of target peptides embedded within self-major histocompatibility complex (MHC) class I molecules. This structure has been described in great detail for several peptide-MHC complexes. In contrast, how T-cell receptors recognize peptide-MHC c...

  19. Functional dynamics of cell surface membrane proteins

    Science.gov (United States)

    Nishida, Noritaka; Osawa, Masanori; Takeuchi, Koh; Imai, Shunsuke; Stampoulis, Pavlos; Kofuku, Yutaka; Ueda, Takumi; Shimada, Ichio

    2014-04-01

    Cell surface receptors are integral membrane proteins that receive external stimuli, and transmit signals across plasma membranes. In the conventional view of receptor activation, ligand binding to the extracellular side of the receptor induces conformational changes, which convert the structure of the receptor into an active conformation. However, recent NMR studies of cell surface membrane proteins have revealed that their structures are more dynamic than previously envisioned, and they fluctuate between multiple conformations in an equilibrium on various timescales. In addition, NMR analyses, along with biochemical and cell biological experiments indicated that such dynamical properties are critical for the proper functions of the receptors. In this review, we will describe several NMR studies that revealed direct linkage between the structural dynamics and the functions of the cell surface membrane proteins, such as G-protein coupled receptors (GPCRs), ion channels, membrane transporters, and cell adhesion molecules.

  20. Evolutionary history of black grouse major histocompatibility complex class IIB genes revealed through single locus sequence-based genotyping

    OpenAIRE

    Strand, Tanja; Wang, Biao; Meyer-Lucht, Yvonne; Höglund, Jacob

    2013-01-01

    Background: Gene duplications are frequently observed in the Major Histocompatibility Complex (MHC) of many species, and as a consequence loci belonging to the same MHC class are often too similar to tell apart. In birds, single locus genotyping of MHC genes has proven difficult due to concerted evolution homogenizing sequences at different loci. But studies on evolutionary history, mode of selection and heterozygosity correlations on the MHC cannot be performed before it is possible to analy...

  1. Molecular cloning and polymorphism of major histocompatibility complex class I genes from grass carp (Ctenophayngodon idellus)

    Institute of Scientific and Technical Information of China (English)

    XIA Chun; XU Guangxian; LIN Changyou; HU Tuanjun; YAN Ruoqian; George F GAO

    2004-01-01

    In order to clarify the molecular sequences,allelic polymorphism and the tertiary structure of grass carp (Ctenophayngodon idellus) MHC class I,and to further study their relationship with disease resistances,grass carp MHC class I gene (Ctid-MHC I) was cloned from a cDNA library and the allelic polymorphism in the population was investigated.The results showed that most of the variations exist in the peptide-binding domain (PBD) and high polymorphism was identified in the Ctid-MHC I allelic genes from 12 individuals.Based on the genetic distance,Ctid-MHC class I can be classified into 6 types (from Ctid-MHC I-UA to Ctid-MHC I-UF) which were subdivided into 9 lineages (from A to I).Comparison of the Ctid-MHC I among animals and humans showed that the key amino acids of the peptide binding sites are conserved.Analysis of the tertiary structure of the PBD between Grass carp and human crystallographic data of HLA-A2,the variation with insertion or deletion was found in eight regions (A~H).The phylogenetic tree of MHC class I indicates the evolution of MHC class I among grass carp,fish,amphibian,birds,higher vertebrates and humans.

  2. IMGT unique numbering for MHC groove G-DOMAIN and MHC superfamily (MhcSF) G-LIKE-DOMAIN

    DEFF Research Database (Denmark)

    Lefranc, Marie-Paule; Duprat, E.; Kaas, Quentin;

    2005-01-01

    IMGT, the international ImMunoGeneTics information system® (http://imgt.cines.fr) provides a common access to expertly annotated data on the genome, proteome, genetics and structure of immunoglobulins (IG), T cell receptors (TR), major histocompatibility complex (MHC), and related proteins...

  3. The functional importance of sequence versus expression variability of MHC alleles in parasite resistance.

    Science.gov (United States)

    Axtner, Jan; Sommer, Simone

    2012-12-01

    Understanding selection processes driving the pronounced allelic polymorphism of the major histocompatibility complex (MHC) genes and its functional associations to parasite load have been the focus of many recent wildlife studies. Two main selection scenarios are currently debated which explain the susceptibility or resistance to parasite infections either by the effects of (1) specific MHC alleles which are selected frequency-dependent in space and time or (2) a heterozygote or divergent allele advantage. So far, most studies have focused only on structural variance in co-evolutionary processes although this might not be the only trait subject to natural selection. In the present study, we analysed structural variance stretching from exon1 through exon3 of MHC class II DRB genes as well as genotypic expression variance in relation to the gastrointestinal helminth prevalence and infection intensity in wild yellow-necked mice (Apodemus flavicollis). We found support for the functional importance of specific alleles both on the sequence and expression level. By resampling a previously investigated study population we identified specific MHC alleles affected by temporal shifts in parasite pressure and recorded associated changes in allele frequencies. The allele Apfl-DRB*23 was associated with resistance to infections by the oxyurid nematode Syphacia stroma and at the same time with susceptibility to cestode infection intensity. In line with our expectation, MHC mRNA transcript levels tended to be higher in cestode-infected animals carrying the allele Apfl-DRB*23. However, no support for a heterozygote or divergent allele advantage on the sequence or expression level was detected. The individual amino acid distance of genotypes did not explain individual differences in parasite loads and the genetic distance had no effect on MHC genotype expression. For ongoing studies on the functional importance of expression variance in parasite resistance, allele

  4. Automated benchmarking of peptide-MHC class I binding predictions

    DEFF Research Database (Denmark)

    Trolle, Thomas; Metushi, Imir G.; Greenbaum, Jason;

    2015-01-01

    the public access to frequent, up-to-date performance evaluations of all participating tools. To overcome potential selection bias in the data included in the IEDB, a strategy was implemented that suggests a set of peptides for which different prediction methods give divergent predictions as to their binding...... educated selections between participating tools. Of the four participating servers, NetMHCpan performed the best, followed by ANN, SMM and finally ARB. Availability and implementation: Up-to-date performance evaluations of each server can be found online at http://tools.iedb.org/auto_bench/mhci/weekly. All...

  5. Evolution of the major histocompatibility complex: Molecular cloning of major histocompatibility complex class I from the amphibian Xenopus

    International Nuclear Information System (INIS)

    Class I major histocopatibility complex (MHC) cDNA clones have been isolated from an expression library derived from mRNA of an MHC homozygous Xenopus laevis. The nucleotide and predicted amino acid sequences show definite similarity to MHC class I molecules of higher vertebrates. The immunoglobulin-likeα-3 domain is more similar to the immunoglobulin-like domains of mammalian class II β chains than to those of mammalian class I molecules, and a tree based on nucleotide sequences of representative MHC genes is presented

  6. Roles for glycosylation of cell surface receptors involved in cellular immune recognition.

    Science.gov (United States)

    Rudd, P M; Wormald, M R; Stanfield, R L; Huang, M; Mattsson, N; Speir, J A; DiGennaro, J A; Fetrow, J S; Dwek, R A; Wilson, I A

    1999-10-22

    The majority of cell surface receptors involved in antigen recognition by T cells and in the orchestration of the subsequent cell signalling events are glycoproteins. The length of a typical N-linked sugar is comparable with that of an immunoglobulin domain (30 A). Thus, by virtue of their size alone, oligosaccharides may be expected to play a significant role in the functions and properties of the cell surface proteins to which they are attached. A databank of oligosaccharide structures has been constructed from NMR and crystallographic data to aid in the interpretation of crystal structures of glycoproteins. As unambiguous electron density can usually only be assigned to the glycan cores, the remainder of the sugar is then modelled into the crystal lattice by superimposing the appropriate oligosaccharide from the database. This approach provides insights into the roles that glycosylation might play in cell surface receptors, by providing models that delineate potential close packing interactions on the cell surface. It has been proposed that the specific recognition of antigen by T cells results in the formation of an immunological synapse between the T cell and the antigen-presenting cell. The cell adhesion glycoproteins, such as CD2 and CD48, help to form a cell junction, providing a molecular spacer between opposing cells. The oligosaccharides located on the membrane proximal domains of CD2 and CD48 provide a scaffold to orient the binding faces, which leads to increased affinity. In the next step, recruitment of the peptide major histocompatibility complex (pMHC) by the T-cell receptors (TCRs) requires mobility on the membrane surface. The TCR sugars are located such that they could prevent non-specific aggregation. Importantly, the sugars limit the possible geometry and spacing of TCR/MHC clusters which precede cell signalling. We postulate that, in the final stage, the sugars could play a general role in controlling the assembly and stabilisation of the

  7. RSCA genotyping of MHC for high-throughput evolutionary studies in the model organism three-spined stickleback Gasterosteus aculeatus

    Directory of Open Access Journals (Sweden)

    Becker Sven

    2009-03-01

    Full Text Available Abstract Background In all jawed vertebrates, highly polymorphic genes of the major histocompatibility complex (MHC encode antigen presenting molecules that play a key role in the adaptive immune response. Their polymorphism is composed of multiple copies of recently duplicated genes, each possessing many alleles within populations, as well as high nucleotide divergence between alleles of the same species. Experimental evidence is accumulating that MHC polymorphism is a result of balancing selection by parasites and pathogens. In order to describe MHC diversity and analyse the underlying mechanisms that maintain it, a reliable genotyping technique is required that is suitable for such highly variable genes. Results We present a genotyping protocol that uses Reference Strand-mediated Conformation Analysis (RSCA, optimised for recently duplicated MHC class IIB genes that are typical for many fish and bird species, including the three-spined stickleback, Gasterosteus aculeatus. In addition we use a comprehensive plasmid library of MHC class IIB alleles to determine the nucleotide sequence of alleles represented by RSCA allele peaks. Verification of the RSCA typing by cloning and sequencing demonstrates high congruency between both methods and provides new insight into the polymorphism of classical stickleback MHC genes. Analysis of the plasmid library additionally reveals the high resolution and reproducibility of the RSCA technique. Conclusion This new RSCA genotyping protocol offers a fast, but sensitive and reliable way to determine the MHC allele repertoire of three-spined sticklebacks. It therefore provides a valuable tool to employ this highly polymorphic and adaptive marker in future high-throughput studies of host-parasite co-evolution and ecological speciation in this emerging model organism.

  8. A locus-wide approach to assessing variation in the avian MHC: the B-locus of the wild turkey.

    Science.gov (United States)

    Chaves, L D; Faile, G M; Hendrickson, J A; Mock, K E; Reed, K M

    2011-07-01

    Studies of major histocompatibility complex (MHC) diversity in non-model vertebrates typically focus on structure and sequence variation in the antigen-presenting loci: the highly variable and polymorphic class I and class IIB genes. Although these studies provide estimates of the number of genes and alleles/locus, they often overlook variation in functionally related and co-inherited genes important in the immune response. This study utilizes the sequence of the MHC B-locus derived from a commercial turkey to investigate MHC variation in wild birds. Sequences were obtained for nine interspersed MHC amplicons (non-class I/II) from each of 40 birds representing 3 subspecies of wild turkey (Meleagris gallopavo). Analysis of aligned sequences identified 238 single-nucleotide variants approximately one-third of which had minor allele frequencies >0.2 in the sampled birds. PHASE analysis identified 70 prospective MHC haplotypes in the wild turkeys, whereas a combined analysis with commercial birds identified almost 100 haplotypes in the species. Denaturing gradient gel electrophoresis (DGGE) of the class IIB loci was used to test the efficacy of single-nucleotide polymorphism (SNP) haplotyping to capture locus-wide variation. Diversity in SNP haplotypes and haplotype sharing among individuals was directly reflected in the DGGE patterns. Utilization of a reference haplotype to sequence interspersed regions of the MHC has significant advantages over other methods of surveying diversity while identifying high-frequency SNPs for genotyping. SNP haplotyping provides a means to identify both divergent haplotypes and homozygous individuals for assessment of immunological variation in wild and domestic populations.

  9. Ethanol Metabolism Alters Major Histocompatibility Complex Class I-Restricted Antigen Presentation In Liver Cells

    Science.gov (United States)

    Osna, Natalia A.; White, Ronda L.; Thiele, Geoffrey M.; Donohue, Terrence M.

    2009-01-01

    The proteasome is a major enzyme that cleaves proteins for antigen presentation. Cleaved peptides traffic to the cell surface, where they are presented in the context of MHC class I. Recognition of these complexes by cytotoxic T lymphocytes is crucial for elimination of cells bearing “non-self” proteins. Our previous studies revealed that ethanol suppresses proteasome function in ethanol-metabolizing liver cells. We hypothesized that proteasome suppression reduces the hydrolysis of antigenic peptides, thereby decreasing the presentation of the peptide-MHC class I-complexes on the cell surface. To test this, we used the mouse hepatocyte cell line (CYP2E1/ADH-transfected HepB5 cells) or primary mouse hepatocytes, both derived from livers of C57Bl/6 mice, which present the ovalbumin peptide, SIINFEKL, complexed with H2Kb. To induce H2Kb expression, HepB5 cells were treated with interferon gamma (IFNγ) and then exposed to ethanol. In these cells, ethanol metabolism decreased not only proteasome activity, but also hydrolysis of the C-extended peptide, SIINFEKL-TE and the presentation of SIINFEKL-H2Kb complexes measured after the delivery of SIINFEKL-TE to cytoplasm. The suppressive effects of ethanol were, in part, attributed to ethanol-elicited impairment of IFNγ signaling. However, in primary hepatocytes, even in the absence of IFNγ, we observed a similar decline in proteasome activity and antigen presentation after ethanol exposure. We conclude that proteasome function is directly suppressed by ethanol metabolism and indirectly, by preventing the activating effects of IFNγ. Ethanol-elicited reduction in proteasome activity contributes to the suppression of SIINFEKL-H2Kb presentation on the surface of liver cells. Immune response to viral antigens plays a crucial role in the pathogenesis of hepatitis C or B viral infections (HCV and HBV, respectively). Professional antigen-presenting cells (dendritic cells and macrophages) are responsible for priming the

  10. HIV-1 Nef targets MHC-I and CD4 for degradation via a final common beta-COP-dependent pathway in T cells.

    Directory of Open Access Journals (Sweden)

    Malinda R Schaefer

    Full Text Available To facilitate viral infection and spread, HIV-1 Nef disrupts the surface expression of the viral receptor (CD4 and molecules capable of presenting HIV antigens to the immune system (MHC-I. To accomplish this, Nef binds to the cytoplasmic tails of both molecules and then, by mechanisms that are not well understood, disrupts the trafficking of each molecule in different ways. Specifically, Nef promotes CD4 internalization after it has been transported to the cell surface, whereas Nef uses the clathrin adaptor, AP-1, to disrupt normal transport of MHC-I from the TGN to the cell surface. Despite these differences in initial intracellular trafficking, we demonstrate that MHC-I and CD4 are ultimately found in the same Rab7(+ vesicles and are both targeted for degradation via the activity of the Nef-interacting protein, beta-COP. Moreover, we demonstrate that Nef contains two separable beta-COP binding sites. One site, an arginine (RXR motif in the N-terminal alpha helical domain of Nef, is necessary for maximal MHC-I degradation. The second site, composed of a di-acidic motif located in the C-terminal loop domain of Nef, is needed for efficient CD4 degradation. The requirement for redundant motifs with distinct roles supports a model in which Nef exists in multiple conformational states that allow access to different motifs, depending upon which cellular target is bound by Nef.

  11. Pivotal molecules of MHC I pathway in human primary hepatocellular carcinoma

    Institute of Scientific and Technical Information of China (English)

    Wei Chen; Mei-Ying Cai; Da-Peng Wei; Xia Wang

    2005-01-01

    AIM: To investigate the expression of several important molecules involved in major histocompatibility complex (MHC) class I presentation pathway in primary hepatocellular carcinoma (HCC), and to determine whether cytotoxic T lymphocyte (CTL) vaccine therapy was suitable for HCC. METHODS: Labeled streptavidin biotin (LSAB) method of immunohisto-chemistry was used to study 33 HCC tissue specimens.RESULTS: Most HCC tissues and adjacent histologicalnormal hepatocytes expressed HLA-I antigens,TAP, andB7, expression of B7 was especially strong, and therewas no significant difference between them (P>0.05).CONCLUSION: The MHC class I presentation pathway in primary hepatocellular carcinoma may not be abnormal or dysfunctional, and CTL could kill these tumor cells.Thus, it is suitable and practicable to design and construct CTL vaccine against HCC.

  12. The pancreatic beta cell surface proteome

    OpenAIRE

    Stützer, I.; Esterházy, D.; Stoffel, M.

    2012-01-01

    The pancreatic beta cell is responsible for maintaining normoglycaemia by secreting an appropriate amount of insulin according to blood glucose levels. The accurate sensing of the beta cell extracellular environment is therefore crucial to this endocrine function and is transmitted via its cell surface proteome. Various surface proteins that mediate or affect beta cell endocrine function have been identified, including growth factor and cytokine receptors, transporters, ion channels and prote...

  13. Methods To Identify Aptamers against Cell Surface Biomarkers

    Directory of Open Access Journals (Sweden)

    Frédéric Ducongé

    2011-09-01

    Full Text Available Aptamers are nucleic acid-based ligands identified through a process of molecular evolution named SELEX (Systematic Evolution of Ligands by Exponential enrichment. During the last 10-15 years, numerous aptamers have been developed specifically against targets present on or associated with the surface of human cells or infectious pathogens such as viruses, bacteria, fungi or parasites. Several of the aptamers have been described as potent probes, rivalling antibodies, for use in flow cytometry or microscopy. Some have also been used as drugs by inhibiting or activating functions of their targets in a manner similar to neutralizing or agonistic antibodies. Additionally, it is straightforward to conjugate aptamers to other agents without losing their affinity and they have successfully been used in vitro and in vivo to deliver drugs, siRNA, nanoparticles or contrast agents to target cells. Hence, aptamers identified against cell surface biomarkers represent a promising class of ligands. This review presents the different strategies of SELEX that have been developed to identify aptamers for cell surface-associated proteins as well as some of the methods that are used to study their binding on living cells.

  14. Interplay among coactivator-associated arginine methyltransferase 1, CBP, and CIITA in IFN-gamma-inducible MHC-II gene expression.

    Science.gov (United States)

    Zika, Eleni; Fauquier, Lucas; Vandel, Laurence; Ting, Jenny P-Y

    2005-11-01

    Class II major histocompatibility (MHC-II) genes are prototype targets of IFN-gamma. IFN-gamma activates the expression of the non-DNA-binding master regulator of MHC-II, class II transactivator (CIITA), which is crucial for enhanceosome formation and gene activation. This report shows the importance of the histone methyltransferase, coactivator-associated arginine methyltransferase (CARM1/PRMT4), during IFN-gamma-induced MHC-II gene activation. It also demonstrates the coordinated regulation of CIITA, CARM1, and the acetyltransferase cyclic-AMP response element binding (CREB)-binding protein (CBP) during this process. CARM1 synergizes with CIITA in activating MHC-II transcription and synergy is abrogated when an arginine methyltransferase-defective CARM1 mutant is used. Protein-arginine methyltransferase 1 has much less effect on MHC-II transcription. Specific RNA interference reduced CARM1 expression as well as MHC-II expression. The recruitment of CARM1 to the promoter requires endogenous CIITA and results in methylation of histone H3-R17; hence, CIITA is an upstream regulator of histone methylation. Previous work has shown that CARM1 can methylate CBP at three arginine residues. Using wild-type CBP and a mutant of CBP lacking the CARM1-targeted arginine residues (R3A), we show that arginine methylation of CBP is required for IFN-gamma induction of MHC-II. A kinetic analysis shows that CIITA, CARM1, and H3-R17 methylation all precede CBP loading on the MHC-II promoter during IFN-gamma treatment. These results suggest functional and temporal relationships among CIITA, CARM1, and CBP for IFN-gamma induction of MHC-II.

  15. Epigenetic control of MHC-II: interplay between CIITA and histone-modifying enzymes.

    Science.gov (United States)

    Zika, Eleni; Ting, Jenny P-Y

    2005-02-01

    Recent advances have shown the crucial role of histone-modifying enzymes in controlling gene activation and repression. This led to the 'histone code' hypothesis, which proposes that combinations of histone modifications work in concert to affect specific gene expression. Mounting evidence suggests that the class II transactivator modulates promoter accessibility by coordinating the recruitment of chromatin modifiers in a time-dependent fashion. MHC-II expression is exquisitely controlled by these highly specific, coordinated and dynamic interactions at the promoter.

  16. The chimpanzee Mhc-DRB region revisited: gene content, polymorphism, pseudogenes, and transcripts

    OpenAIRE

    de Groot, Natasja G.; Corrine M C Heijmans; de Groot, Nanine; Doxiadis, Gaby G M; Otting, Nel; Bontrop, Ronald E

    2009-01-01

    In humans, great apes, and different monkey species, the major histocompatibility complex (MHC) class II DRB region is known to display considerable copy number variation. The microsatellite D6S2878 has been shown to be a valuable marker for haplotyping the DR region in humans and macaque species. The present report illustrates that chimpanzee haplotypes also can be discriminated with this marker. The analyses resulted in the description of nine different region configurations, of which seven...

  17. Lactate induced HIF-1α-PRMT1 cross talk affects MHC I expression in monocytes.

    Science.gov (United States)

    Gupta, Piyushi; Singh, Ankita; Gowda, Pruthvi; Ghosh, Sadashib; Chatterjee, Arpita; Sen, Ellora

    2016-10-01

    Tumor infiltrating monocytes play a crucial role in tumor immune surveillance. As lactate is an important component of the tumor milieu, we investigated its role in the transcriptional regulation of MHC I which is crucial for mounting effective immune responses against tumors. Lactate elevated MHC class I expression in monocytes. Increase in HLAB expression was concomitant with increase in HIF-1α and decrease in PRMT1 levels. Interestingly, a reciprocal relationship was observed between PRMT1 and HIF-1α. While HIF-1α inhibition decreased lactate induced MHC I, both pharmacological inhibition and siRNA mediated knockdown of PRMT1 upregulated HLAB levels. PRMT1 over-expression rescued lactate mediated increase in MHC I expression. Lactate mediated changes in nucleosomal occupancy on HLAB promoter facilitated a chromatin landscape that favoured decreased recruitment of CREB and PRMT1 on CRE site of HLAB locus. The effect of lactate on the chromatin landscape of HLAB was completely mimicked by PRMT1 inhibitor AMI-1 in terms of nucleosomal occupancy and CREB recruitment. Besides demonstrating the importance of lactate in the transcriptional regulation of HLAB, this study highlights for the first time the (i) existence of HIF-1α-PRMT1 regulatory loop and (ii) role of PRMT1 in modulating chromatin landscape crucial for facilitating HLAB gene expression. PMID:27521225

  18. Real-time, high-throughput measurements of peptide-MHC-I dissociation using a scintillation proximity assay

    DEFF Research Database (Denmark)

    Harndahl, Mikkel; Rasmussen, Michael; Røder, Gustav Andreas;

    2011-01-01

    timed data needed to determine the rate of dissociation is not simple. Ideally, one should use a homogenous assay involving an inexhaustible and label-free assay principle. Here, we present a homogenous, high-throughput peptide-MHC class I dissociation assay, which by and large fulfill these ideal...

  19. Sensitive quantitative predictions of peptide-MHC binding by a 'Query by Committee' artificial neural network approach

    DEFF Research Database (Denmark)

    Buus, S; Lauemøller, S L; Worning, P;

    2003-01-01

    We have generated Artificial Neural Networks (ANN) capable of performing sensitive, quantitative predictions of peptide binding to the MHC class I molecule, HLA-A*0204. We have shown that such quantitative ANN are superior to conventional classification ANN, that have been trained to predict...

  20. Major histocompatibility complex class I expression on neurons in subacute sclerosing panencephalitis and experimental subacute measles encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Gogate, N.; Yamabe, Toshio; Verma, L.; Dhib-Jalbut, S. [Univ. of Maryland, Baltimore, MD (United States)] [and others

    1996-04-01

    Lack of major histocompatibility class I antigens on neurons has been implicated as a possible mechanism for viral persistence in the brain since these antigens are required for cytotoxic T-lymphocyte recognition of infected cells. In subacute sclerosing panencephalitis (SSPE), measles virus (MV) persists in neurons, resulting in a fatal chronic infection. MHC class I mRNA expression was examined in formalin-fixed brain tissue from 6 SSPE patients by in situ hybridization. In addition MHC class I protein expression in MV-infected neurons was examined in experimental Subacute Measles Encephalitis (SME) by double immunohistochemistry. MHC class I mRNA expression was found to be upregulated in SSPE tissues studied, and in 5 out of 6 cases the expression was definitively seen on neurons. The percentage of neurons expressing MHC class I mRNA ranged between 20 to 84% in infected areas. There was no correlation between the degree of infection and expression of MHC class I molecules on neurons. Importantly, the number of neurons co-expressing MHC class I and MV antigens was markedly low, varying between 2 to 8%. Similar results were obtained in SME where 20 to 30% of the neurons expressed MHC class I but < 8% co-expressed MHC class I and MV antigens. Perivascular infiltrating cells in the infected regions in SME expressed IFN{gamma} immunoreactivity. The results suggest that MV may not be directly involved in the induction of MHC class I on neurons and that cytokines such as IFN{gamma} may play an important role. Furthermore, the paucity of neurons co-expressing MHC class I and MV antigens in SSPE and SME suggests that such cells are either rapidly cleared by cytotoxic T lymphocytes (CTL), or, alternatively, lack of co-expression of MHC class I on MV infected neurons favors MV persistence in these cells by escaping CTL recognition. 33 refs., 3 figs., 3 tabs.

  1. The combination of major histocompatibility complex (MHC) and non-MHC genes influences murine lymphocytic choriomeningitis virus pathogenesis

    DEFF Research Database (Denmark)

    Eyler, Y L; Pfau, C J; Broomhall, K S;

    1989-01-01

    with the recessive disease phenotype. In all cases, susceptibility was dominant. In backcross progeny obtained from matings of parental strains differing in both major histocompatibility complex (MHC) and non-MHC (SWR; C3H), 90% of the challenged mice died, indicating that at least three loci controlled...... susceptibility to the disease. When the parental strains carried similar MHC haplotypes but dissimilar background genes (B10.BR; CBA), 78% of the backcross mice succumbed, indicating that at least two non-MHC loci influenced disease susceptibility. It is unlikely, however, that the same two non-MHC loci...... are critical in all genetic combinations, since F1 produced from two H-2 identical, resistant strains (B10.BR; C3H) were found to be fully susceptible. When congenic mice, differing only in the D-end of the MHC region, were analysed, 50% of the backcross animals died, indicating that one gene in the MHC region...

  2. Organization and characteristics of the major histocompatibility complex class II region in the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis).

    Science.gov (United States)

    Ruan, Rui; Ruan, Jue; Wan, Xiao-Ling; Zheng, Yang; Chen, Min-Min; Zheng, Jin-Song; Wang, Ding

    2016-01-01

    Little is known about the major histocompatibility complex (MHC) in the genome of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) (YFP) or other cetaceans. In this study, a high-quality YFP bacterial artificial chromosome (BAC) library was constructed. We then determined the organization and characterization of YFP MHC class II region by screening the BAC library, followed by sequencing and assembly of positive BAC clones. The YFP MHC class II region consists of two segregated contigs (218,725 bp and 328,435 bp respectively) that include only eight expressed MHC class II genes, three pseudo MHC genes and twelve non-MHC genes. The YFP has fewer MHC class II genes than ruminants, showing locus reduction in DRB, DQA, DQB, and loss of DY. In addition, phylogenic and evolutionary analyses indicated that the DRB, DQA and DQB genes might have undergone birth-and-death evolution, whereas the DQB gene might have evolved under positive selection in cetaceans. These findings provide an essential foundation for future work, such as estimating MHC genetic variation in the YFP or other cetaceans. This work is the first report on the MHC class II region in cetaceans and offers valuable information for understanding the evolution of MHC genome in cetaceans. PMID:26932528

  3. A Highly Tilted Binding Mode by a Self-Reactive T Cell Receptor Results in Altered Engagement of Peptide and MHC

    Energy Technology Data Exchange (ETDEWEB)

    D Sethi; D Schubert; A Anders; A Heroux; D Bonsor; C Thomas; E Sundberg; J Pyrdol; K Wucherpfennig

    2011-12-31

    Self-reactive T cells that escape elimination in the thymus can cause autoimmune pathology, and it is therefore important to understand the structural mechanisms of self-antigen recognition. We report the crystal structure of a T cell receptor (TCR) from a patient with relapsing-remitting multiple sclerosis that engages its self-peptide-major histocompatibility complex (pMHC) ligand in an unusual manner. The TCR is bound in a highly tilted orientation that prevents interaction of the TCR-{alpha} chain with the MHC class II {beta} chain helix. In this structure, only a single germline-encoded TCR loop engages the MHC protein, whereas in most other TCR-pMHC structures all four germline-encoded TCR loops bind to the MHC helices. The tilted binding mode also prevents peptide contacts by the short complementarity-determining region (CDR) 3{beta} loop, and interactions that contribute to peptide side chain specificity are focused on the CDR3{alpha} loop. This structure is the first example in which only a single germline-encoded TCR loop contacts the MHC helices. Furthermore, the reduced interaction surface with the peptide may facilitate TCR cross-reactivity. The structural alterations in the trimolecular complex are distinct from previously characterized self-reactive TCRs, indicating that there are multiple unusual ways for self-reactive TCRs to bind their pMHC ligand.

  4. Making the animal model for AIDS research more precise: the impact of major histocompatibility complex (MHC) genes on pathogenesis and disease progression in SIV-infected monkeys.

    Science.gov (United States)

    Sauermann, U

    2001-09-01

    Experimentally infected rhesus monkeys serve as an indispensable animal model to assess the pathogenesis, to validate therapy approaches and to develop vaccination strategies against viral diseases such as AIDS threatening the human population. Upon infection with simian immunodeficiency virus (SIV), a retrovirus closely related to the human immunodeficiency virus (HIV), macaques develop clinical manifestations similar to those of HIV-infected humans. As in humans, the disease course is variable. Polymorphic genes of the major histocompatibility complex (MHC) are required for the initiation and regulation of a specific immune response and represent a major host factor accounting for the differential outcome of infection. During the last few years, our understanding of the structure and function of the rhesus macaque MHC has increased substantially. Functional studies have led to the identification of specific SIV and HIV peptide epitopes presented by rhesus macaque MHC molecules. The subsequent development of MHC class I tetramers has allowed further insight into the cellular immune response following SIV-infection. Detailed studies demonstrated that viral escape mutants are generated during the acute and chronic phase of infection and explain why control of viral replication ultimately fails. Furthermore, particular MHC haplotypes which influence disease progression have been discovered. Thus, MHC-typing can have a prognostic potential. The further elucidation of the rhesus macaque MHC and the search for other relevant genes will remain an important task for future research and will stimulate all immunologically-related investigations in macaques. PMID:11899095

  5. Individual odortypes: Interaction of MHC and background genes

    Energy Technology Data Exchange (ETDEWEB)

    Willse, Alan R.; Kwak, Jae; Yamazaki, Kunio; Preti, George; Wahl, Jon H.; Beauchamp, Gary

    2006-12-01

    Genes of the major histocompatibility complex (MHC) influence the urinary odors of mice. Behavioral studies have shown (1) that mice differing only at MHC have distinct urinary odors, suggesting an MHC odor phenotype or odortype; (2) that the MHC odortype can be recognized across different (potentially interfering) background strains; and (3) that the MHC odortype is not an additive trait. Very little is known about the odorants underlying this behavioral phenotype. We compared urinary volatile metabolite profiles of two MHC haplotypes (H-2b and H-2k) and their heterozygous cross (H-2b ? H-2k) for two different background strains using SPME headspace analysis followed by gas chromatography/mass spectrometry. For a surprisingly large number of compounds an MHC association was found to be moderated by background genotype (i.e., there is a significant MHC ? background interaction effect in the statistical model relating genotype to relative compound concentration). A few compounds have an MHC association that is independent of background strain, consistent with MHC discriminations across background strains observed in behavioral experiments. Perhaps more relevant to the role of MHC in social settings where odors are perceived combinatorially, numerous relative ratios between pairs of compounds were found to discriminate MHC types invariant of background type. In addition, a heterozygous effect ? where the metabolite expression (concentration) for the heterozygote is more extreme than the expression for either homozygote ? was observed for many compounds. The large number of compounds involved as well as the strong background and heterozygous influence suggest a complex (but unknown) mechanism of MHC-related odor expression.

  6. Inhibition of Heavy Chain and β2-Microglobulin Synthesis as a Mechanism of Major Histocompatibility Complex Class I Downregulation during Epstein-Barr Virus Replication▿

    OpenAIRE

    Guerreiro-Cacais, Andre Ortlieb; Uzunel, Mehmet; Levitskaya, Jelena; Levitsky, Victor

    2006-01-01

    The mechanisms of major histocompatibility complex (MHC) class I downregulation during Epstein-Barr virus (EBV) replication are not well characterized. Here we show that in several cell lines infected with a recombinant EBV strain encoding green fluorescent protein (GFP), the virus lytic cycle coincides with GFP expression, which thus can be used as a marker of virus replication. EBV replication resulted in downregulation of MHC class II and all classical MHC class I alleles independently of ...

  7. Nanotomography of Cell Surfaces with Evanescent Fields

    Directory of Open Access Journals (Sweden)

    Michael Wagner

    2008-01-01

    Full Text Available The technique of variable-angle total internal reflection fluorescence microscopy (TIRFM and its application to nanotomography of cell surfaces are described. Present applications include (1 3D imaging of chromosomes in their metaphase to demonstrate axial resolution in the nanometre range, (2 measurements of cell-substrate topology, which upon cholesterol depletion shows some loosening of cell-substrate contacts, and (3 measurements of cell topology upon photodynamic therapy (PDT, which demonstrate cell swelling and maintenance of focal contacts. The potential of the method for in vitro diagnostics, but also some requirements and limitations are discussed.

  8. MHC-I affects infection intensity but not infection status with a frequent avian malaria parasite in blue tits.

    Directory of Open Access Journals (Sweden)

    Helena Westerdahl

    Full Text Available Host resistance against parasites depends on three aspects: the ability to prevent, control and clear infections. In vertebrates the immune system consists of innate and adaptive immunity. Innate immunity is particularly important for preventing infection and eradicating established infections at an early stage while adaptive immunity is slow, but powerful, and essential for controlling infection intensities and eventually clearing infections. Major Histocompatibility Complex (MHC molecules are central in adaptive immunity, and studies on parasite resistance and MHC in wild animals have found effects on both infection intensity (parasite load and infection status (infected or not. It seems MHC can affect both the ability to control infection intensities and the ability to clear infections. However, these two aspects have rarely been considered simultaneously, and their relative importance in natural populations is therefore unclear. Here we investigate if MHC class I genotype affects infection intensity and infection status with a frequent avian malaria infection Haemoproteus majoris in a natural population of blue tits Cyanistes caeruleus. We found a significant negative association between a single MHC allele and infection intensity but no association with infection status. Blue tits that carry a specific MHC allele seem able to suppress H. majoris infection intensity, while we have no evidence that this allele also has an effect on clearance of the H. majoris infection, a result that is in contrast with some previous studies of MHC and avian malaria. A likely explanation could be that the clearance rate of avian malaria parasites differs between avian malaria lineages and/or between avian hosts.

  9. Genetic basis for MHC-dependent mate choice.

    Science.gov (United States)

    Yamazaki, Kunio; Beauchamp, Gary K

    2007-01-01

    Genes in the major histocompatibility complex (MHC), best known for their role in immune recognition and transplantation success, are also involved in modulating mate choice in mice. Early studies with inbred, congenic mouse lines showed that mate choice tended to favor nonself MHC types. A similar phenomenon was demonstrated with semi-wild mice as well. Subsequent studies showed that, rather than nonself choices, it was more accurate to say that mice chose nonparental MHC types for mates since preferences for nonself could be reversed if mice were fostered from birth on parents with nonself MHC types. Other studies have demonstrated that parent-offspring recognition is also regulated by MHC-determined signals suggesting that this system is one of general importance for mouse behavior. Many studies have now demonstrated that volatile mouse body odors are regulated by MHC genes and it is presumably these odor differences that underlie mate choice and familial recognition. Recent studies have shown that many odorants are controlled by the MHC but the mechanism by which MHC genes exert their influence has not been identified. Surprisingly, not only are volatile body odors influenced by MHC genes but so too are nonvolatile signals. Peptides bound to the MHC protein may also function in individual recognition. The extent to which this system is involved in mate choice of other species is unclear although there are some suggestive studies. Indeed, there is tentative evidence that MHC differences, presumably acting via odor changes, may influence human partner selection. Further studies should clarify both the mechanism underlying MHC influence on body odors as well as the generality of their importance in mate selection.

  10. MHCcluster, a method for functional clustering of MHC molecules

    OpenAIRE

    Thomsen, Martin; Lundegaard, Claus; Buus, Søren; Lund, Ole; Nielsen, Morten

    2013-01-01

    The identification of peptides binding to major histocompatibility complexes (MHC) is a critical step in the understanding of T cell immune responses. The human MHC genomic region (HLA) is extremely polymorphic comprising several thousand alleles, many encoding a distinct molecule. The potentially unique specificities remain experimentally uncharacterized for the vast majority of HLA molecules. Likewise, for nonhuman species, only a minor fraction of the known MHC molecules have been characte...

  11. Aged mice have increased inflammatory monocyte concentration and altered expression of cell-surface functional receptors

    Indian Academy of Sciences (India)

    Kelley Strohacker; Whitney L Breslin; Katie C Carpenter; Brian K McFarlin

    2012-03-01

    The expression of monocyte cell-surface receptors represents one index of immune dysfunction, which is common with aging. Although mouse models of aging are prevalent, monocyte subset assessment is rare. Our purpose was to compare cell receptor expression on classic (CD115+/Gr-1high) and non-classic (CD115+/Gr-1low) monocytes from 80- or 20-week-old CD-1 mice. Three-colour flow cytometry was used to determine the concentration of monocyte subsets and their respective cell-surface expression of TLR2, TLR4, CD80, CD86, MHC II and CD54. These receptors were selected because they have been previously associated with altered monocyte function. Data were analysed with independent -tests; significance was set at < 0.05. Old mice had a greater concentration of both classic (258%, =0.003) and non-classic (70%, =0.026) monocytes. The classic : non-classic monocyte ratio doubled in old as compared with that in young mice (=0.006), indicating a pro-inflammatory shift. TLR4 ($\\downarrow$27%, =0.001) and CD80 ($\\downarrow$37%, =0.004) were decreased on classic monocytes from old as compared with those from young mice. TLR2 ($\\uparrow$24%, =0.002) and MHCII ($\\downarrow$21%, =0.026) were altered on non-classic monocytes from old as compared with those from young mice. The increased classic : non-classic monocyte ratio combined with changes in the cell-surface receptor expression on both monocyte subsets is indicative of immune dysfunction, which may increase age-associated disease risk.

  12. Construction of enkaryotic expression vector of major histocompatibility complex class Ⅰ -related chain A and establishment of its stable transfected%MHC-Ⅰ类链相关基因A真核表达载体的构建及稳定转染舌鳞癌细胞的实验研究

    Institute of Scientific and Technical Information of China (English)

    李超; 杨丹; 石芳琼; 李跃辉; 陈新群; 翦新春; 蒋灿华

    2011-01-01

    目的 构建人类MHC-Ⅰ类链相关基因A(MICA)的真核表达载体,转染人舌鳞癌脑高转移Tca8113-Tb细胞,建立稳定过表达MICA基因的口腔鳞癌细胞系.方法 采用PCR技术扩增pCMV-SPORT6-MICA中编码MICA基因的cDNA序列,重组至有绿色荧光蛋白标记的真核表达载体pEGFP-N1,构建最终的表达载体pEGFP-N1-MICA,脂质体法转染Tca8113-Tb细胞,G418筛选,荧光显微镜下观察绿色荧光蛋白的表达,有限稀释法建立稳定过表达MICA基因的Tca8113-Tb细胞系,RT-PCR、real time PCR和免疫细胞化学检测MICA在该细胞中的表达.结果 通过PCR技术获取TMICA基因并成功克隆入载体,测序鉴定该序列与GenBank中的序列相同.转染的细胞可见绿色荧光蛋白表达,RT-PCR、real time PCR及免疫细胞化学检测到目的 基因MICA在转染细胞中为过表达.结论 pEGFP-N1-MICA真核表达载体的成功构建与稳定转染Tca8113-Tb细胞系的建立,为进一步研究该基因的功能奠定了良好的实验基础.%Objective To construct the eukaryotic expression vector, encoding major histocompatibility complex class Ⅰ -related chain A gene(MICA), for the further research of transfecting Tca8113-Tb cell line(a metastatic cell line of brain metastasis from human tongue cancer Tea8113 cells in nude mouse), and to establish a stable MICA overexpression oral squamons cell line. Methods eDNA of MICA gene from pCMV-SPORT6-MICA was amplified by PCR,and subcloned into eukaryotic expression vector pEGFP-N1 marked with green fluorescent protein (GFP). The recombinant plasmid was sequenced and transfected into Tca8ll3-Tb cell line by lipofectamineTM 2000. After screen culture by C418, stable tranfected Tca8ll3-Tb cell line was established using definite dilution method. The expressions of GFP protein was viewed directly with fluorescence microscopy and the overexpression of MICA was identified by RT-PCR,real time PCR and immunocytochemistry. Results The MICA gene was

  13. Trophoblast Major Histocompatibility Complex Class I Expression Is Associated with Immune-Mediated Rejection of Bovine Fetuses Produced by Cloning.

    Science.gov (United States)

    Rutigliano, Heloisa M; Thomas, Aaron J; Wilhelm, Amanda; Sessions, Benjamin R; Hicks, Brady A; Schlafer, Donald H; White, Kenneth L; Davies, Christopher J

    2016-08-01

    Trophoblast cells from bovine somatic cell nuclear transfer (SCNT) conceptuses express major histocompatibility complex class I (MHC-I) proteins early in gestation, and this may be one cause of the significant first-trimester embryonic mortality observed in these pregnancies. MHC-I homozygous-compatible (n = 9), homozygous-incompatible (n = 8), and heterozygous-incompatible (n = 5) SCNT pregnancies were established. The control group consisted of eight pregnancies produced by artificial insemination. Uterine and placental samples were collected on Day 35 ± 1 of pregnancy, and expression of MHC-I, leukocyte markers, and cytokines were examined by immunohistochemistry. Trophoblast cells from all SCNT pregnancies expressed MHC-I, while trophoblast cells from age-matched control pregnancies were negative for MHC-I expression. Expression of MHC-I antigens by trophoblast cells from SCNT pregnancies was associated with lymphocytic infiltration in the endometrium. Furthermore, MHC-I-incompatible conceptuses, particularly the heterozygous-incompatible ones, induced a more pronounced lymphocytic infiltration than MHC-I-compatible conceptuses. Cells expressing cluster of differentiation (CD) 3, gamma/deltaTCR, and MHC-II were increased in the endometrium of SCNT pregnancies compared to the control group. CD4(+) lymphocytes were increased in MHC-I-incompatible pregnancies compared to MHC-I-compatible and control pregnancies. CD8(+), FOXP3(+), and natural killer cells were increased in MHC-I heterozygous-incompatible SCNT pregnancies compared to homozygous SCNT and control pregnancies. PMID:27385783

  14. MHCcluster, a method for functional clustering of MHC molecules

    DEFF Research Database (Denmark)

    Thomsen, Martin Christen Frølund; Lundegaard, Claus; Buus, Søren;

    2013-01-01

    binding specificity. The method has a flexible web interface that allows the user to include any MHC of interest in the analysis. The output consists of a static heat map and graphical tree-based visualizations of the functional relationship between MHC variants and a dynamic TreeViewer interface where...... both the functional relationship and the individual binding specificities of MHC molecules are visualized. We demonstrate that conventional sequence-based clustering will fail to identify the functional relationship between molecules, when applied to MHC system, and only through the use of the...

  15. Variation in positively selected major histocompatibility complex class I loci in rufous-collared sparrows (Zonotrichia capensis).

    Science.gov (United States)

    Jones, Matthew R; Cheviron, Zachary A; Carling, Matthew D

    2014-12-01

    The major histocompatibility complex (MHC) is a highly variable family of genes involved in parasite recognition and the initiation of adaptive immune system responses. Variation in MHC loci is maintained primarily through parasite-mediated selection or disassortative mate choice. To characterize MHC diversity of rufous-collared sparrows (Zonotrichia capensis), an abundant South American passerine, we examined allelic and nucleotide variation in MHC class I exon 3 using pyrosequencing. Exon 3 comprises a substantial portion of the peptide-binding region (PBR) of class I MHC and thus plays an important role in intracellular pathogen defense. We identified 98 putatively functional alleles that produce 56 unique protein sequences across at least 6 paralogous loci. Allelic diversity per individual and exon-wide nucleotide diversity were relatively low; however, we found specific amino acid positions with high nucleotide diversity and signatures of positive selection (elevated d N /d S ) that may correspond to the PBR. Based on the variation in physicochemical properties of amino acids at these "positively selected sites," we identified ten functional MHC supertypes. Spatial variation in nucleotide diversity and the number of MHC alleles, proteins, and supertypes per individual suggests that environmental heterogeneity may affect patterns of MHC diversity. Furthermore, populations with high MHC diversity have higher prevalence of avian malaria, consistent with parasite-mediated selection on MHC. Together, these results provide a framework for subsequent investigations of selective agents acting on MHC in Z. capensis. PMID:25186067

  16. Structural and Functional Characterization of a Single-chain Peptide-MHC Molecule that Modulates both Naive and Activated CD8plus T Cells

    Energy Technology Data Exchange (ETDEWEB)

    D Samanta; G Mukherjee; U Ramagopal; R Chaparro; S Nathenson; T DiLorenzo; S Almo

    2011-12-31

    Peptide-MHC (pMHC) multimers, in addition to being tools for tracking and quantifying antigen-specific T cells, can mediate downstream signaling after T-cell receptor engagement. In the absence of costimulation, this can lead to anergy or apoptosis of cognate T cells, a property that could be exploited in the setting of autoimmune disease. Most studies with class I pMHC multimers used noncovalently linked peptides, which can allow unwanted CD8{sup +} T-cell activation as a result of peptide transfer to cellular MHC molecules. To circumvent this problem, and given the role of self-reactive CD8{sup +} T cells in the development of type 1 diabetes, we designed a single-chain pMHC complex (scK{sup d}.IGRP) by using the class I MHC molecule H-2K{sup d} and a covalently linked peptide derived from islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP{sub 206-214}), a well established autoantigen in NOD mice. X-ray diffraction studies revealed that the peptide is presented in the groove of the MHC molecule in canonical fashion, and it was also demonstrated that scK{sup d}.IGRP tetramers bound specifically to cognate CD8{sup +} T cells. Tetramer binding induced death of naive T cells and in vitro- and in vivo-differentiated cytotoxic T lymphocytes, and tetramer-treated cytotoxic T lymphocytes showed a diminished IFN-{gamma} response to antigen stimulation. Tetramer accessibility to disease-relevant T cells in vivo was also demonstrated. Our study suggests the potential of single-chain pMHC tetramers as possible therapeutic agents in autoimmune disease. Their ability to affect the fate of naive and activated CD8{sup +} T cells makes them a potential intervention strategy in early and late stages of disease.

  17. A community resource benchmarking predictions of peptide binding to MHC-I molecules

    DEFF Research Database (Denmark)

    Peters, B; Bui, HH; Pletscher-Frankild, Sune;

    2006-01-01

    of entire pathogen proteomes for peptide likely to bind MHC. Here we make public a large set of 48,828 quantitative peptide-binding affinity measurements relating to 48 different mouse, human, macaque, and chimpanzee MHC class I alleles. We use this data to establish a set of benchmark predictions with one...... neural network method and two matrix-based prediction methods extensively utilized in our groups. In general, the neural network outperforms the matrix-based predictions mainly due to its ability to generalize even on a small amount of data. We also retrieved predictions from tools publicly available...... of newly developed prediction methods. In addition, to generate and evaluate our own prediction methods, we have established an easily extensible web-based prediction framework that allows automated side-by-side comparisons of prediction methods implemented by experts. This is an advance over the current...

  18. A community resource benchmarking predictions of peptide binding to MHC-I molecules.

    Directory of Open Access Journals (Sweden)

    Bjoern Peters

    2006-06-01

    Full Text Available Recognition of peptides bound to major histocompatibility complex (MHC class I molecules by T lymphocytes is an essential part of immune surveillance. Each MHC allele has a characteristic peptide binding preference, which can be captured in prediction algorithms, allowing for the rapid scan of entire pathogen proteomes for peptide likely to bind MHC. Here we make public a large set of 48,828 quantitative peptide-binding affinity measurements relating to 48 different mouse, human, macaque, and chimpanzee MHC class I alleles. We use this data to establish a set of benchmark predictions with one neural network method and two matrix-based prediction methods extensively utilized in our groups. In general, the neural network outperforms the matrix-based predictions mainly due to its ability to generalize even on a small amount of data. We also retrieved predictions from tools publicly available on the internet. While differences in the data used to generate these predictions hamper direct comparisons, we do conclude that tools based on combinatorial peptide libraries perform remarkably well. The transparent prediction evaluation on this dataset provides tool developers with a benchmark for comparison of newly developed prediction methods. In addition, to generate and evaluate our own prediction methods, we have established an easily extensible web-based prediction framework that allows automated side-by-side comparisons of prediction methods implemented by experts. This is an advance over the current practice of tool developers having to generate reference predictions themselves, which can lead to underestimating the performance of prediction methods they are not as familiar with as their own. The overall goal of this effort is to provide a transparent prediction evaluation allowing bioinformaticians to identify promising features of prediction methods and providing guidance to immunologists regarding the reliability of prediction tools.

  19. Immune escape from NY-ESO-1-specific T-cell therapy via loss of heterozygosity in the MHC.

    Science.gov (United States)

    Klippel, Z K; Chou, J; Towlerton, A M; Voong, L N; Robbins, P; Bensinger, W I; Warren, E H

    2014-03-01

    Adoptive immunotherapy of tumors with T cells specific for the cancer-testis antigen NY-ESO-1 has shown great promise in preclinical models and in early stage clinical trials. Tumor persistence or recurrence after NY-ESO-1-specific therapy occurs, however, and the mechanisms of recurrence remain poorly defined. In a murine xenograft model of NY-ESO-1(+) multiple myeloma, we observed tumor recurrence after adoptive transfer of CD8(+) T cells genetically redirected to the prototypic NY-ESO-1157-165 peptide presented by HLA-A*02:01. Analysis of the myeloma cells that had escaped from T-cell control revealed intact expression of NY-ESO-1 and B2M, but selective, complete loss of HLA-A*02:01 expression from the cell surface. Loss of heterozygosity (LOH) in the major histocompatibility complex (MHC) involving the HLA-A locus was identified in the tumor cells, and further analysis revealed selective loss of the allele encoding HLA-A*02:01. Although LOH involving the MHC has not been described in myeloma patients with persistent or recurrent disease after immune therapies such as allogeneic hematopoietic cell transplantation (HCT), it has been described in patients with acute myelogenous leukemia who relapsed after allogeneic HCT. These results suggest that MHC loss should be evaluated in patients with myeloma and other cancers who relapse after adoptive NY-ESO-1-specific T-cell therapy.

  20. Mortality selection during the 2003 European heat wave in three-spined sticklebacks: effects of parasites and MHC genotype

    Directory of Open Access Journals (Sweden)

    Milinski Manfred

    2008-04-01

    Full Text Available Abstract Background Ecological interaction strength may increase under environmental stress including temperature. How such stress enhances and interacts with parasite selection is almost unknown. We studied the importance of resistance genes of the major histocompatibility complex (MHC class II in 14 families of three-spined sticklebacks Gasterosteus aculeatus exposed to their natural macroparasites in field enclosures in the extreme summer of 2003. Results After a mass die-off during the 2003-European heat wave killing 78% of 277 experimental fish, we found strong differences in survival among and within families. In families with higher average parasite load fewer individuals survived. Multivariate analysis revealed that the composition of the infecting parasite fauna was family specific. Within families, individuals with an intermediate number of MHC class IIB sequence variants survived best and had the lowest parasite load among survivors, suggesting a direct functional link between MHC diversity and fitness. The within family MHC effects were, however, small compared to between family effects, suggesting that other genetic components or non-genetic effects were also important. Conclusion The correlation between parasite load and mortality that we found at both individual and family level might have appeared only in the extraordinary heatwave of 2003. Due to global warming the frequency of extreme climatic events is predicted to increase, which might intensify costs of parasitism and enhance selection on immune genes.

  1. Genetic variation in the odorant receptors family 13 and the mhc loci influence mate selection in a multiple sclerosis dataset

    Directory of Open Access Journals (Sweden)

    Hauser Stephen L

    2010-11-01

    Full Text Available Abstract Background When selecting mates, many vertebrate species seek partners with major histocompatibility complex (MHC genes different from their own, presumably in response to selective pressure against inbreeding and towards MHC diversity. Attempts at replication of these genetic results in human studies, however, have reached conflicting conclusions. Results Using a multi-analytical strategy, we report validated genome-wide relationships between genetic identity and human mate choice in 930 couples of European ancestry. We found significant similarity between spouses in the MHC at class I region in chromosome 6p21, and at the odorant receptor family 13 locus in chromosome 9. Conversely, there was significant dissimilarity in the MHC class II region, near the HLA-DQA1 and -DQB1 genes. We also found that genomic regions with significant similarity between spouses show excessive homozygosity in the general population (assessed in the HapMap CEU dataset. Conversely, loci that were significantly dissimilar among spouses were more likely to show excessive heterozygosity in the general population. Conclusions This study highlights complex patterns of genomic identity among partners in unrelated couples, consistent with a multi-faceted role for genetic factors in mate choice behavior in human populations.

  2. Techniques to Study Specific Cell-Surface Receptor-Mediated Cellular Vitamin A Uptake

    OpenAIRE

    KAWAGUCHI, RIKI; Sun, Hui

    2010-01-01

    STRA6 is a multitransmembrane domain protein that was recently identified as the cell-surface receptor for plasma retinol binding protein (RBP), the vitamin A carrier protein in the blood. STRA6 binds to RBP with high affinity and mediates cellular uptake of vitamin A from RBP. It is not homologous to any known receptors, transporters, and channels, and it represents a new class of membrane transport protein. Consistent with the diverse physiological functions of vitamin A, STRA6 is widely ex...

  3. Analysis of chickens for recombination within the MHC (B-complex)

    DEFF Research Database (Denmark)

    Skjødt, K; Koch, C; Crone, M

    1985-01-01

    In an attempt to further map the chicken MHC (the B complex), a systematic search for genetic recombinants within the B complex was performed by serotyping the progeny from F2 crosses of chickens by means of specific anti-class I, anti-class II, and anti-class IV alloantisera. Two recombinant B......-haplotypes (B21r and B15r) were found by analysing 2,656 F2 chickens representing 5,312 informative typings. In either case, the B-G (class IV) allele was recombined with both the B-F and B-L alleles of the opposite haplotype. MLC typings, tests for direct compatibility by GVH reactions, and absorption analyses...

  4. Molecular and pathogenic effects of endoplasmic reticulum aminopeptidases ERAP1 and ERAP2 in MHC-I-associated inflammatory disorders: Towards a unifying view.

    Science.gov (United States)

    López de Castro, José A; Alvarez-Navarro, Carlos; Brito, Ariadna; Guasp, Pablo; Martín-Esteban, Adrian; Sanz-Bravo, Alejandro

    2016-09-01

    The inflammatory diseases that are most strongly associated with major histocompatibility Complex class I (MHC-I) alleles are also influenced by endoplasmic reticulum aminopeptidase (ERAP) 1 and/or 2, often in epistasis with the susceptibility MHC-I allele. This review will focus on the four major MHC-I-associated inflammatory disorders: ankylosing spondylitis, birdshot chorioretinopathy, Behçet's disease and psoriasis. The genetics of ERAP1/ERAP2 association and the alterations induced by polymorphism of these enzymes on the risk MHC-I allotypes will be examined. A pattern emerges of analogous effects on peptide length, sequence and affinity of disparate peptidomes, suggesting that similar peptide-mediated mechanisms underlie the pathogenesis and the joint contribution of ERAP1/ERAP2 and MHC-I to distinct inflammatory diseases. Processing of specific antigens, peptide-dependent changes in global properties of the MHC-I molecules, such as folding and stability, or both may be pathogenic. PMID:27522479

  5. The Cell Surface Proteome of Human Mesenchymal Stromal Cells

    OpenAIRE

    Christian Niehage; Charlotte Steenblock; Theresia Pursche; Martin Bornhäuser; Denis Corbeil; Bernard Hoflack

    2011-01-01

    BACKGROUND: Multipotent human mesenchymal stromal cells (hMSCs) are considered as promising biological tools for regenerative medicine. Their antibody-based isolation relies on the identification of reliable cell surface markers. METHODOLOGY/PRINCIPAL FINDINGS: To obtain a comprehensive view of the cell surface proteome of bone marrow-derived hMSCs, we have developed an analytical pipeline relying on cell surface biotinylation of intact cells using cell impermeable, cleavable sulfo-NHS-SS-bio...

  6. Colonizing the world in spite of reduced MHC variation

    Science.gov (United States)

    Gangoso, L.; Alcaide, M.; Grande, J.M.; Muñoz, J.; Talbot, Sandra L.; Sonsthagen, Sarah A.; Sage, Kevin; Figuerola, J.

    2012-01-01

    Reduced immune gene diversity is thought to negatively affect the capacity of organisms to adapt to pathogen challenges, which represent a major force in natural selection. Genes of the Major Histocompatibility Complex (MHC) are the most widely invoked adaptive loci in conservation biology, and have become the most popular genetic markers to investigate pathogen-host interactions in vertebrates. Although MHC genes are the most polymorphic genes described in the vertebrate genome, the extent to which MHC diversity determines the long-term persistence of populations is, unclear and often debated, as recent studies have documented the occurrence of natural populations thriving even after a depletion of MHC diversity caused by genetic drift. Here, we show that some phylogenetically related species belonging to the Falco genus (Aves: Falconidae) present a dramatically low MHC variability that has not precluded, nevertheless, the successful colonization of almost all existing regions and habitats worldwide. We found evidence for two remarkably different patterns of MHC variation within the genus. While kestrels show a high MHC variation according to the general theory, falcons exhibit an ancestrally low intra- and inter-specific MHC allelic diversity. We provide compelling evidence that this pattern is not caused by the degeneration of functional genes into pseudogenes, the inadvertent analyses of paralogous MHC genes, or the devastating action of genetic drift. Instead, our results strongly support the idea of an evolutionary transition driven and maintained by natural selection from primarily highly variable towards low polymorphic, but functional and expressed, MHC genes with species-specific pathogen-recognition capabilities.

  7. Efficient assembly of recombinant major histocompatibility complex class I molecules with preformed disulfide bonds

    DEFF Research Database (Denmark)

    Ostergaard Pedersen, L; Nissen, Mogens Holst; Hansen, N J;

    2001-01-01

    The expression of major histocompatibility class I (MHC-I) crucially depends upon the binding of appropriate peptides. MHC-I from natural sources are therefore always preoccupied with peptides complicating their purification and analysis. Here, we present an efficient solution to this problem...... suggests that de novo folding of denatured MHC-I molecules proceed efficiently if directed by preformed disulfide bond(s). Importantly, these molecules express serological epitopes and stain specific T cells; and they bind peptides specifically. Several denatured MHC-I heavy chains were analyzed and shown...

  8. Structures of two major histocompatibility complex class I genes of the rainbow trout (Oncorhynchus mykiss)

    NARCIS (Netherlands)

    Shum, B.P.; Mason, P.M.; Magor, K.E.; Flodin, L.R.; Stet, R.J.M.; Parham, P.

    2002-01-01

    Abstract. Here we describe two rainbow trout major histocompatibility complex (MHC) class I genes characterized from 5 phage genomic clones prepared from a single fish. Clone GC71 contains all exons except a leader peptide-encoding exon. An open reading frame is maintained, and thus the gene MhcOnmy

  9. Impact of peptides on the recognition of HLA class I molecules by human HLA antibodies.

    Science.gov (United States)

    Mulder, Arend; Eijsink, Chantal; Kester, Michel G D; Franke, Marry E I; Kardol, Marrie J; Heemskerk, Mirjam H M; van Kooten, Cees; Verreck, Frank A; Drijfhout, Jan Wouter; Koning, Frits; Doxiadis, Ilias I N; Claas, Frans H J

    2005-11-01

    MHC class I molecules expressed on cell surfaces are composed of H chain, beta2-microglobulin and any of a vast array of peptides. The role of peptide in the recognition of HLA class I by serum HLA Abs is unknown. In this study, the solid-phase assay of a series (n = 11) of HLA-A2-reactive, pregnancy-induced, human mAbs on a panel (n = 12) of recombinant monomeric HLA-A2 molecules, each containing a single peptide, revealed peptide selectivity of the mAbs. The flow cytometry membrane staining intensities on the HLA-A2-transduced cell line K562, caused by these mAbs, correlated with the number of monomer species detected by the mAbs. Flow cytometry staining on HLA-A2-bearing cell lines of a variety of lineages was indicative of tissue selectivity of these HLA-A2 mAbs. This tissue selectivity suggests that the deleterious effect on allografts is confined to alloantibodies recognizing only HLA class I loaded with peptides that are derived from tissue-specific and household proteins. Since Abs that are only reactive with HLA loaded with irrelevant peptides are expected to be harmless toward allografts, the practice of HLA Ab determination on lymphocyte-derived HLA deserves reconsideration.

  10. Spatially and temporally fluctuating selection at non-MHC immune genes: evidence from TAP polymorphism in populations of brown trout ( Salmo trutta , L.)

    DEFF Research Database (Denmark)

    Jensen, L.F.; Hansen, Michael Møller; Mensberg, Karen-Lise Dons;

    2008-01-01

    molecules that are central to the major histocompatibility complex (MHC) class I restricted antigen presentation and thus integral components in the adaptive immune system. As such, they could be influenced by selection, driven by pathogens and parasites in a manner similar to MHC genes. Analysis of allele......Temporal samples of Danish brown trout (Salmo trutta) from populations representing varying geographical scales were analysed using eight putatively neutral microsatellite loci and two microsatellite loci embedded in TAP genes (Transporter associated with Antigen Processing). These genes encode....... Moreover, signals of divergent selection among temporal samples within localities suggest that selection also might fluctuate at a temporal scale. These results suggest that immune genes other than the classical MHC class I and II might be subject to selection and warrant further studies of functional...

  11. Engagement of major histocompatibility complex class I and class II molecules up-regulates intercellular adhesion of human B cells via a CD11/CD18-independent mechanism.

    Science.gov (United States)

    Alcover, A; Juillard, V; Acuto, O

    1992-02-01

    We have studied the role of major histocompatibility complex (MHC) molecules in the regulation of intercellular adhesion of human B cells. We found that molecules able to bind to MHC class II molecules, such as monoclonal antibodies or staphylococcal enterotoxins, induced rapid and sustained homotypic adhesion of Epstein-Barr virus (EBV)-transformed B cell lines as well as peripheral blood B lymphocytes. Moreover, anti-MHC class I monoclonal antibodies also stimulated intercellular adherence. Adhesion induced upon MHC engagement was faster and stronger than that triggered by phorbol esters. It needed active metabolism, but divalent cations were not required. Monoclonal antibodies directed against LFA-1 (CD11a/CD18) or its ligand ICAM-1 (CD54) did not inhibit MHC class II-induced homotypic adhesion of various EBV-transformed B cell lines, nor of a variant of the B cell line Raji expressing very low LFA-1 surface levels. Moreover, EBV-transformed B cells from a severe lymphocyte adhesion deficiency patient, lacking surface CD11/CD18, also aggregated in response to anti-MHC class I or class II monoclonal antibodies. Together these data indicate that engagement of MHC molecules may transduce signals to B cells resulting in up-regulation of intercellular adhesion, via an LFA-1-independent mechanism. This may play a role in the stabilization of T cell/antigen-presenting cell conjugates at the moment of antigen recognition.

  12. An MHC-I cytoplasmic domain/HIV-1 Nef fusion protein binds directly to the mu subunit of the AP-1 endosomal coat complex.

    Directory of Open Access Journals (Sweden)

    Rajendra Kumar Singh

    Full Text Available BACKGROUND: The down-regulation of the major histocompatibility complex class I (MHC-I from the surface of infected cells by the Nef proteins of primate immunodeficiency viruses likely contributes to pathogenesis by providing evasion of cell-mediated immunity. HIV-1 Nef-induced down-regulation involves endosomal trafficking and a cooperative interaction between the cytoplasmic domain (CD of MHC-I, Nef, and the clathrin adaptor protein complex-1 (AP-1. The CD of MHC-I contains a key tyrosine within the sequence YSQA that is required for down-regulation by Nef, but this sequence does not conform to the canonical AP-binding tyrosine-based motif Yxxphi, which mediates binding to the medium (micro subunits of AP complexes. We previously proposed that Nef allows the MHC-I CD to bind the mu subunit of AP-1 (micro1 as if it contained a Yxxphimotif. METHODS AND FINDINGS: Here, we show that a direct interaction between the MHC-I CD/Nef and micro1 plays a primary role in the down-regulation of MHC-I: GST pulldown assays using recombinant proteins indicated that most of the MHC-I CD and Nef residues that are required for the down-regulation in human cells contribute to direct interactions with a truncated version of micro1. Specifically, the tyrosine residue of the YSQA sequence in the MHC-I CD as well as Nef residues E62-65 and P78 each contributed to the interaction between MHC-I CD/Nef and micro1 in vitro, whereas Nef M20 had little to no role. Conversely, residues F172/D174 and V392/L395 of the binding pocket on micro1 for Yxxphi motifs were required for a robust interaction. CONCLUSIONS: These data indicate that the MHC-I cytoplasmic domain, Nef, and the C-terminal two thirds of the mu subunit of AP-1 are sufficient to constitute a biologically relevant interaction. The data also reveal an unexpected role for a hydrophobic pocket in micro1 for interaction with MHC-I CD/Nef.

  13. Major Histocompatibility Complex (MHC) markers in conservation biology.

    Science.gov (United States)

    Ujvari, Beata; Belov, Katherine

    2011-01-01

    Human impacts through habitat destruction, introduction of invasive species and climate change are increasing the number of species threatened with extinction. Decreases in population size simultaneously lead to reductions in genetic diversity, ultimately reducing the ability of populations to adapt to a changing environment. In this way, loss of genetic polymorphism is linked with extinction risk. Recent advances in sequencing technologies mean that obtaining measures of genetic diversity at functionally important genes is within reach for conservation programs. A key region of the genome that should be targeted for population genetic studies is the Major Histocompatibility Complex (MHC). MHC genes, found in all jawed vertebrates, are the most polymorphic genes in vertebrate genomes. They play key roles in immune function via immune-recognition and -surveillance and host-parasite interaction. Therefore, measuring levels of polymorphism at these genes can provide indirect measures of the immunological fitness of populations. The MHC has also been linked with mate-choice and pregnancy outcomes and has application for improving mating success in captive breeding programs. The recent discovery that genetic diversity at MHC genes may protect against the spread of contagious cancers provides an added impetus for managing and protecting MHC diversity in wild populations. Here we review the field and focus on the successful applications of MHC-typing for conservation management. We emphasize the importance of using MHC markers when planning and executing wildlife rescue and conservation programs but stress that this should not be done to the detriment of genome-wide diversity. PMID:21954351

  14. Manipulation of MHC-I/TCR Interaction for Immune Therapy

    Institute of Scientific and Technical Information of China (English)

    Qingjun Liu; Bin Gao

    2008-01-01

    Adoptive immunotherapy involving the transfer of autologous tumor or virus-reactive T lymphocytes has been demonstrated to he effective in the eradication of cancer and vitally infected cells. Identification of MHC-restricted antigens and progress in generation of adaptive immune responses have provided new direction for such treatment for severe pathologies such as cancer and autoimmune diseases. Here we review the latest development about the molecular basis of MHC-I/TCR interaction, and it's manipulation including enhanced MHC-I expression, modification of peptide and engineered TCR for clinical applications such as vaccine design, tumor therapy and autoimmune diseases. Cellular & Molecular Immunology. 2008;5(3):171-182.

  15. The poxviral scrapin MV-LAP requires a myxoma viral infection context to efficiently downregulate MHC-I molecules.

    Science.gov (United States)

    Collin, Nicolas; Guérin, Jean-Luc; Drexler, Ingo; Blanié, Sophie; Gelfi, Jacqueline; Boullier, Séverine; Foucras, Gilles; Sutter, Gerd; Messud-Petit, Frédérique

    2005-12-20

    Downregulation of MHC class I molecules is a strategy developed by some viruses to escape cellular immune responses. Myxoma virus (MV), a poxvirus causing rabbit myxomatosis, encodes MV-LAP that is known to increase MHC-I endocytosis and degradation through a C(4)HC(3) motif critical for an E3 ubiquitin ligase activity. Here, we performed a functional mapping of MV-LAP and showed that not only the C(4)HC(3) motif is necessary for a marked downregulation of MHC-I but also a conserved region in the C-terminal part of the protein. We also showed that the putative transmembrane domains are responsible for a specific subcellular localization of the protein: they retain MV-LAP in the ER in transfected cells and in the endolysosomal compartments in infected cells. We observed that a specific MV infection context is necessary for a fully efficient downregulation of MHC-I. Our data suggest that the functionality of viral LAP factors, inherited by herpes- and poxviruses from mammalian cells, is more complex than anticipated. PMID:16185739

  16. MHC-correlated mate choice in humans: a review.

    Science.gov (United States)

    Havlicek, Jan; Roberts, S Craig

    2009-05-01

    Extremely high variability in genes of the major histocompatibility complex (MHC) in vertebrates is assumed to be a consequence of frequency-dependent parasite-driven selection and mate preferences based on promotion of offspring heterozygosity at MHC, or potentially, genome-wide inbreeding avoidance. Where effects have been found, mate choice studies on rodents and other species usually find preference for MHC-dissimilarity in potential partners. Here we critically review studies on MHC-associated mate choice in humans. These are based on three broadly different aspects: (1) odor preferences, (2) facial preferences and (3) actual mate choice surveys. As in animal studies, most odor-based studies demonstrate disassortative preferences, although there is variation in the strength and nature of the effects. In contrast, facial attractiveness research indicates a preference for MHC-similar individuals. Results concerning MHC in actual couples show a bias towards similarity in one study, dissimilarity in two studies and random distribution in several other studies. These vary greatly in sample size and heterogeneity of the sample population, both of which may significantly bias the results. This pattern of mixed results across studies may reflect context-dependent and/or life history sensitive preference expression, in addition to higher level effects arising out of population differences in genetic heterogeneity or cultural and ethnic restrictions on random mating patterns. Factors of special relevance in terms of individual preferences are reproductive status and long- vs. short-term mating context. We discuss the idea that olfactory and visual channels may work in a complementary way (i.e. odor preference for MHC-dissimilarity and visual preference for MHC-similarity) to achieve an optimal level of genetic variability, methodological issues and interesting avenues for further research.

  17. Lipopeptides: a novel antigen repertoire presented by major histocompatibility complex class I molecules.

    Science.gov (United States)

    Morita, Daisuke; Sugita, Masahiko

    2016-10-01

    Post-translationally modified peptides, such as those containing either phosphorylated or O-glycosylated serine/threonine residues, may be presented to cytotoxic T lymphocytes (CTLs) by MHC class I molecules. Most of these modified peptides are captured in the MHC class I groove in a similar manner to that for unmodified peptides. N-Myristoylated 5-mer lipopeptides have recently been identified as a novel chemical class of MHC class I-presented antigens. The rhesus classical MHC class I allele, Mamu-B*098, was found to be capable of binding N-myristoylated lipopeptides and presenting them to CTLs. A high-resolution X-ray crystallographic analysis of the Mamu-B*098:lipopeptide complex revealed that the myristic group as well as conserved C-terminal serine residue of the lipopeptide ligand functioned as anchors, whereas the short stretch of three amino acid residues located in the middle of the lipopeptides was only exposed externally with the potential to interact directly with specific T-cell receptors. Therefore, the modes of lipopeptide-ligand interactions with MHC class I and with T-cell receptors are novel and fundamentally distinct from that for MHC class I-presented peptides. Another lipopeptide-presenting MHC class I allele has now been identified, leading us to the prediction that MHC class I molecules may be separated on a functional basis into two groups: one presenting long peptides and the other presenting short lipopeptides. Since the N-myristoylation of viral proteins is often linked to pathogenesis, CTLs capable of sensing N-myristoylation may serve to control pathogenic viruses, raising the possibility for the development of a new type of lipopeptide vaccine. PMID:27402593

  18. Female rose bitterling prefer MHC-dissimilar males: experimental evidence.

    Directory of Open Access Journals (Sweden)

    Martin Reichard

    Full Text Available The role of genetic benefits in female mate choice remains a controversial aspect of sexual selection theory. In contrast to "good allele" models of sexual selection, "compatible allele" models of mate choice predict that females prefer mates with alleles complementary to their own rather than conferring additive effects. While correlative results suggest complementary genetic effects to be plausible, direct experimental evidence is scarce. A previous study on the Chinese rose bitterling (Rhodeus ocellatus demonstrated a positive correlation between female mate choice, offspring growth and survival, and the functional dissimilarity between the Major Histocompatibility Complex (MHC alleles of males and females. Here we directly tested whether females used cues associated with MHC genes to select genetically compatible males in an experimental framework. By sequentially pairing females with MHC similar and dissimilar males, based on a priori known MHC profiles, we showed that females discriminated between similar and dissimilar males and deposited significantly more eggs with MHC dissimilar males. Notably, the degree of dissimilarity was an important factor for female decision to mate, possibly indicating a potential threshold value of dissimilarity for decision making, or of an indirect effect of the MHC.

  19. MHC haplotype involvement in avian resistance to an ectoparasite.

    Science.gov (United States)

    Owen, Jeb P; Delany, Mary E; Mullens, Bradley A

    2008-10-01

    Research on immune function in evolutionary ecology has frequently focused on avian ectoparasites (e.g., mites and lice). However, host immunogenetics involved with bird resistance to ectoparasites has not been determined. The critical role of the major histocompatibility complex (MHC) in adaptive immunity and high genetic variation found within the MHC make this gene complex useful for exploring the immunogenetic basis for bird resistance to ectoparasites. The objective of this study was to determine if the avian MHC influenced resistance to a blood-feeding ectoparasite. Four congenic lines of chickens, differing only at the MHC, were comparatively infested with a cosmopolitan ectoparasite of birds-northern fowl mite (NFM)-which is also a serious pest species of poultry. Mite infestations were monitored over time and mite densities (weekly and maximum) were compared among lines. Chickens with the MHC haplotype B21 were relatively resistant to NFM, compared with birds in the B15 congenic line (P density were tested. The highest peak NFM populations occurred more often on hens with the B15 haplotype versus the B21 haplotype (P = 0.012), which supported the results of the congenic study. These data indicate the avian MHC influences ectoparasite resistance, which is relevant to disease ecology and avian-ectoparasite interaction. PMID:18626638

  20. Calreticulin: Roles in Cell-Surface Protein Expression

    Directory of Open Access Journals (Sweden)

    Yue Jiang

    2014-09-01

    Full Text Available In order to perform their designated functions, proteins require precise subcellular localizations. For cell-surface proteins, such as receptors and channels, they are able to transduce signals only when properly targeted to the cell membrane. Calreticulin is a multi-functional chaperone protein involved in protein folding, maturation, and trafficking. However, evidence has been accumulating that calreticulin can also negatively regulate the surface expression of certain receptors and channels. In these instances, depletion of calreticulin enhances cell-surface expression and function. In this review, we discuss the role of calreticulin with a focus on its negative effects on the expression of cell-surface proteins.

  1. 454 sequencing reveals extreme complexity of the class II Major Histocompatibility Complex in the collared flycatcher

    Directory of Open Access Journals (Sweden)

    Gustafsson Lars

    2010-12-01

    Full Text Available Abstract Background Because of their functional significance, the Major Histocompatibility Complex (MHC class I and II genes have been the subject of continuous interest in the fields of ecology, evolution and conservation. In some vertebrate groups MHC consists of multiple loci with similar alleles; therefore, the multiple loci must be genotyped simultaneously. In such complex systems, understanding of the evolutionary patterns and their causes has been limited due to challenges posed by genotyping. Results Here we used 454 amplicon sequencing to characterize MHC class IIB exon 2 variation in the collared flycatcher, an important organism in evolutionary and immuno-ecological studies. On the basis of over 152,000 sequencing reads we identified 194 putative alleles in 237 individuals. We found an extreme complexity of the MHC class IIB in the collared flycatchers, with our estimates pointing to the presence of at least nine expressed loci and a large, though difficult to estimate precisely, number of pseudogene loci. Many similar alleles occurred in the pseudogenes indicating either a series of recent duplications or extensive concerted evolution. The expressed alleles showed unambiguous signals of historical selection and the occurrence of apparent interlocus exchange of alleles. Placing the collared flycatcher's MHC sequences in the context of passerine diversity revealed transspecific MHC class II evolution within the Muscicapidae family. Conclusions 454 amplicon sequencing is an effective tool for advancing our understanding of the MHC class II structure and evolutionary patterns in Passeriformes. We found a highly dynamic pattern of evolution of MHC class IIB genes with strong signals of selection and pronounced sequence divergence in expressed genes, in contrast to the apparent sequence homogenization in pseudogenes. We show that next generation sequencing offers a universal, affordable method for the characterization and, in perspective

  2. Identification of 48 full-length MHC-DAB functional alleles in miiuy croaker and evidence for positive selection.

    Science.gov (United States)

    Liu, Jiang; Sun, Yueyan; Xu, Tianjun

    2016-07-01

    Major histocompatibility complex (MHC) molecules play a vital role in the immune response and are a highly polymorphic gene superfamily in vertebrates. As the molecular marker associated with polymorphism and disease susceptibility/resistance, the polymorphism of MHC genes has been investigated in many tetrapods and teleosts. Most studies were focused on the polymorphism of the second exon, which encodes the peptide-binding region (PBR) in the α1- or β1-domain, but few studies have examined the full-length coding region. To comprehensive investigate the polymorphism of MHC gene, we identified 48 full-length miiuy croaker (Miichthys miiuy) MHC class IIB (Mimi-DAB) functional alleles from 26 miiuy croaker individuals. All of the alleles encode 34 amino acid sequences, and a high level of polymorphism was detected in Mimi-DAB alleles. The rate of non-synonymous substitutions (dN) occurred at a significantly higher frequency than that of synonymous substitutions (dS) in the PBR, and this result suggests that balancing selection maintains polymorphisms at the Mimi-DAB locus. Phylogenetic analysis based on the full-length and exon 2 sequences of Mimi-DAB alleles both showed that the Mimi-DAB alleles were clustered into two major groups. A total of 19 positive selected sites were identified on the Mimi-DAB alleles after testing for positive selection, and 14 sites were predicted to be associated with antigen-binding sites, which suggests that most of selected sites are significant for disease resistance. The polymorphism of Mimi-DAB alleles provides an important resource for analyzing the association between the polymorphism of MHC gene and disease susceptibility/resistance, and for researching the molecular selective breeding of miiuy croaker with enhanced disease resistance. PMID:27164216

  3. Analysis of porcine MHC expression profile

    Institute of Scientific and Technical Information of China (English)

    JIANG Fanbo; CHEN Chen; DENG Yajun; YU Jun; HU Songnian

    2005-01-01

    The porcine major histocompatibility complex (MHC, also named swine leukocyte antigen, SLA) is associated not only with immune responsibility and disease susceptibility, but also with some reproductive and productive traits such as growth rate and carcass composition. As yet systematical research on SLA expression profile is not reported. In order to illustrate SLA expression comprehensively and deepen our understanding of its function, we outlined the expression profile of SLA in 51 tissues of Landrace by analyzing a large amount of ESTs produced by "Sino-Danish Porcine Genome Project". In addition, we also compared the expression profile of SLA in several tissues from different development stages and from another breed (Erhualian). The result shows: (i) classical SLA genes are highly expressed in immune tissues and middle part of intestine; (ii) although SLA-3 is an SLA Ia gene, its expression abundance and pattern are quite different from those of the other two SLA Ia genes. The same phenomenon is seen in HLA-C expression, suggesting that the two genes may function similarly and undergo convergent evolution; (iii) except in jejunum, the antigen presenting genes are more highly expressed in breed Erhualian than in Landrace. The difference might associate with the higher resistance to bad conditions (including pathogens) of Erhualian and higher growth rates of Landrace.

  4. An update on the contribution of the MHC to AS susceptibility.

    Science.gov (United States)

    Reveille, John D

    2014-06-01

    The 40-year-old association of HLA-B27 with ankylosing spondylitis is one of the best examples of disease association with a hereditary marker. Genomewide association and family studies suggest that other important major histocompatibility complex (MHC) influences are operative in ankylosing spondylitis (AS) susceptibility. HLA-B27 positive hepatitis C individuals are immunologically more efficient in combating viral infections such as HIV-1, hepatitis C, and influenza and less efficient in combating against certain bacteria (and perhaps other organisms) capable of surviving intracellularly. A recent representative population survey of the frequency of HLA-B27 in the USA found a lower frequency of HLA-B27 in older US adults, perhaps reflecting this. Other HLA class I and class II alleles have been implicated in AS susceptibility, the most consistent being HLA-B*40/B60 (B*40:01) but also B14, B15, A*0201, DRB1*04:04, and certain DPA1 and DPB1 alleles. Non-HLA MHC alleles have also been implicated, although many such studies have been inconsistent, likely due to power issues related to the low number of HLA-B27-negative AS patients examined. The best evidence is for major histocompatibility complex class I chain-related gene A (MICA) whose recognition by intestinal epithelial T cells expressing different V-delta-1 gamma/delta TCR further implicates the gut in AS pathogenesis. The HLA class I and class II and other non-HLA allelic associations underscore the importance of T cells in AS pathogenesis. PMID:24838411

  5. Efficacy of Marek's disease vaccines in Mhc heterozygous chickens: Mhc congenic x inbred line F1 matings.

    Science.gov (United States)

    Bacon, L D; Witter, R L

    1995-01-01

    The goal of this study is to demonstrate that Mhc (B) heterozygous chickens differ in efficacy of response to several Marek's disease (MD) vaccines. Four types of B2 heterozygotes, in addition to B2B2 homozygotes, were developed by crossing 15.B congenic males to inbred line 7(1) (B2B2) hens. The five types of F1 chicks were intermingled in isolators and vaccinated with one of four types of MD vaccine before inoculation with the very virulent Md5 strain of MD herpesvirus. The F1 chickens differ in development of protective immunity following MD vaccination from two perspectives. First, chickens of a particular Mhc genotype were protected better by some vaccines than others. Second, individual vaccine preparations protected some Mhc genotypes more effectively. We conclude that some MD vaccines are more appropriate than others for certain B-haplotypes when chickens are heterozygous for the Mhc. The value of using Mhc-congenic x inbred line F1 animals for studies concerning the influence of the Mhc on vaccinal immunity is discussed.

  6. Cholesterol Corrects Altered Conformation of MHC-II Protein in Leishmania donovani Infected Macrophages: Implication in Therapy

    Science.gov (United States)

    Chakrabarti, Saikat; Roy, Syamal

    2016-01-01

    Background Previously we reported that Kala-azar patients show progressive decrease in serum cholesterol as a function of splenic parasite burden. Splenic macrophages (MΦ) of Leishmania donovani (LD) infected mice show decrease in membrane cholesterol, while LD infected macrophages (I-MΦ) show defective T cell stimulating ability that could be corrected by liposomal delivery of cholesterol. T helper cells recognize peptide antigen in the context of class II MHC molecule. It is known that the conformation of a large number of membrane proteins is dependent on membrane cholesterol. In this investigation we tried to understand the influence of decreased membrane cholesterol in I-MΦ on the conformation of MHC-II protein and peptide-MHC-II stability, and its bearing on the antigen specific T-cell activation. Methodology/Principal Findings MΦ of CBA/j mice were infected with Leishmania donovani (I-MΦ). Two different anti-Aκ mAbs were used to monitor the status of MHC-II protein under parasitized condition. One of them (11.5–2) was conformation specific, whereas the other one (10.2.16) was not. Under parasitized condition, the binding of 11.5–2 decreased significantly with respect to the normal counterpart, whereas that of 10.2.16 remained unaltered. The binding of 11.5–2 was restored to normal upon liposomal delivery of cholesterol in I-MΦ. By molecular dynamics (MD) simulation studies we found that there was considerable conformational fluctuation in the transmembrane domain of the MHC-II protein in the presence of membrane cholesterol than in its absence, which possibly influenced the distal peptide binding groove. This was evident from the faster dissociation of the cognate peptide from peptide-MHC complex under parasitized condition, which could be corrected by liposomal delivery of cholesterol in I-MΦ. Conclusion The decrease in membrane cholesterol in I-MΦ may lead to altered conformation of MHC II, and this may contribute to a faster dissociation of

  7. Genetic analysis of completely sequenced disease-associated MHC haplotypes identifies shuffling of segments in recent human history.

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available The major histocompatibility complex (MHC is recognised as one of the most important genetic regions in relation to common human disease. Advancement in identification of MHC genes that confer susceptibility to disease requires greater knowledge of sequence variation across the complex. Highly duplicated and polymorphic regions of the human genome such as the MHC are, however, somewhat refractory to some whole-genome analysis methods. To address this issue, we are employing a bacterial artificial chromosome (BAC cloning strategy to sequence entire MHC haplotypes from consanguineous cell lines as part of the MHC Haplotype Project. Here we present 4.25 Mb of the human haplotype QBL (HLA-A26-B18-Cw5-DR3-DQ2 and compare it with the MHC reference haplotype and with a second haplotype, COX (HLA-A1-B8-Cw7-DR3-DQ2, that shares the same HLA-DRB1, -DQA1, and -DQB1 alleles. We have defined the complete gene, splice variant, and sequence variation contents of all three haplotypes, comprising over 259 annotated loci and over 20,000 single nucleotide polymorphisms (SNPs. Certain coding sequences vary significantly between different haplotypes, making them candidates for functional and disease-association studies. Analysis of the two DR3 haplotypes allowed delineation of the shared sequence between two HLA class II-related haplotypes differing in disease associations and the identification of at least one of the sites that mediated the original recombination event. The levels of variation across the MHC were similar to those seen for other HLA-disparate haplotypes, except for a 158-kb segment that contained the HLA-DRB1, -DQA1, and -DQB1 genes and showed very limited polymorphism compatible with identity-by-descent and relatively recent common ancestry (<3,400 generations. These results indicate that the differential disease associations of these two DR3 haplotypes are due to sequence variation outside this central 158-kb segment, and that shuffling of

  8. Cell surface carbohydrates as prognostic markers in human carcinomas

    DEFF Research Database (Denmark)

    Dabelsteen, Erik

    1996-01-01

    Tumour development is usually associated with changes in cell surface carbohydrates. These are often divided into changes related to terminal carbohydrate structures, which include incomplete synthesis and modification of normally existing carbohydrates, and changes in the carbohydrate core struc...

  9. A mass spectrometric-derived cell surface protein atlas.

    Directory of Open Access Journals (Sweden)

    Damaris Bausch-Fluck

    Full Text Available Cell surface proteins are major targets of biomedical research due to their utility as cellular markers and their extracellular accessibility for pharmacological intervention. However, information about the cell surface protein repertoire (the surfaceome of individual cells is only sparsely available. Here, we applied the Cell Surface Capture (CSC technology to 41 human and 31 mouse cell types to generate a mass-spectrometry derived Cell Surface Protein Atlas (CSPA providing cellular surfaceome snapshots at high resolution. The CSPA is presented in form of an easy-to-navigate interactive database, a downloadable data matrix and with tools for targeted surfaceome rediscovery (http://wlab.ethz.ch/cspa. The cellular surfaceome snapshots of different cell types, including cancer cells, resulted in a combined dataset of 1492 human and 1296 mouse cell surface glycoproteins, providing experimental evidence for their cell surface expression on different cell types, including 136 G-protein coupled receptors and 75 membrane receptor tyrosine-protein kinases. Integrated analysis of the CSPA reveals that the concerted biological function of individual cell types is mainly guided by quantitative rather than qualitative surfaceome differences. The CSPA will be useful for the evaluation of drug targets, for the improved classification of cell types and for a better understanding of the surfaceome and its concerted biological functions in complex signaling microenvironments.

  10. A mass spectrometric-derived cell surface protein atlas.

    Science.gov (United States)

    Bausch-Fluck, Damaris; Hofmann, Andreas; Bock, Thomas; Frei, Andreas P; Cerciello, Ferdinando; Jacobs, Andrea; Moest, Hansjoerg; Omasits, Ulrich; Gundry, Rebekah L; Yoon, Charles; Schiess, Ralph; Schmidt, Alexander; Mirkowska, Paulina; Härtlová, Anetta; Van Eyk, Jennifer E; Bourquin, Jean-Pierre; Aebersold, Ruedi; Boheler, Kenneth R; Zandstra, Peter; Wollscheid, Bernd

    2015-01-01

    Cell surface proteins are major targets of biomedical research due to their utility as cellular markers and their extracellular accessibility for pharmacological intervention. However, information about the cell surface protein repertoire (the surfaceome) of individual cells is only sparsely available. Here, we applied the Cell Surface Capture (CSC) technology to 41 human and 31 mouse cell types to generate a mass-spectrometry derived Cell Surface Protein Atlas (CSPA) providing cellular surfaceome snapshots at high resolution. The CSPA is presented in form of an easy-to-navigate interactive database, a downloadable data matrix and with tools for targeted surfaceome rediscovery (http://wlab.ethz.ch/cspa). The cellular surfaceome snapshots of different cell types, including cancer cells, resulted in a combined dataset of 1492 human and 1296 mouse cell surface glycoproteins, providing experimental evidence for their cell surface expression on different cell types, including 136 G-protein coupled receptors and 75 membrane receptor tyrosine-protein kinases. Integrated analysis of the CSPA reveals that the concerted biological function of individual cell types is mainly guided by quantitative rather than qualitative surfaceome differences. The CSPA will be useful for the evaluation of drug targets, for the improved classification of cell types and for a better understanding of the surfaceome and its concerted biological functions in complex signaling microenvironments. PMID:25894527

  11. Major Histocompatibility Complex (MHC Markers in Conservation Biology

    Directory of Open Access Journals (Sweden)

    Katherine Belov

    2011-08-01

    Full Text Available Human impacts through habitat destruction, introduction of invasive species and climate change are increasing the number of s