A new polymorphic and multicopy MHC gene family related to nonmammalian class I

Energy Technology Data Exchange (ETDEWEB)

Leelayuwat, C.; Degli-Esposti, M.A.; Abraham, L.J. [Univ. of Western Australia, Perth (Australia); Townend, D.C. [Sir Charles Gairdner Hospital, Perth (Australia); Dawkins, R.L. [Royal Perth Hospital, Perth (Australia)]|[Univ. of Western Australia, Perth (Australia)]|[Sir Charles Gairdner Hospital, Perth (Australia)

1994-12-31

The authors have used genomic analysis to characterize a region of the central major histocompatibility complex (MHC) spanning {approximately} 300 kilobases (kb) between TNF and HLA-B. This region has been suggested to carry genetic factors relevant to the development of autoimmune diseases such as myasthenia gravis (MG) and insulin dependent diabetes mellitus (IDDM). Genomic sequence was analyzed for coding potential, using two neural network programs, GRAIL and GeneParser. A genomic probe, JAB, containing putative coding sequences (PERB11) located 60 kb centromeric of HLA-B, was used for northern analysis of human tissues. Multiple transcripts were detected. Southern analysis of genomic DNA and overlapping YAC clones, covering the region from BAT1 to HLA-F, indicated that there are at least five copies of PERB11, four of which are located within this region of the MHC. The partial cDNA sequence of PERB11 was obtained from poly-A RNA derived from skeletal muscle. The putative amino acid sequence of PERB11 shares {approximately} 30% identity to MHC class I molecules from various species, including reptiles, chickens, and frogs, as well as to other MHC class I-like molecules, such as the IgG FcR of the mouse and rat and the human Zn-{alpha}2-glycoprotein. From direct comparison of amino acid sequences, it is concluded that PERB11 is a distinct molecule more closely related to nonmammalian than known mammalian MHC class I molecules. Genomic sequence analysis of PERB11 from five MHC ancestral haplotypes (AH) indicated that the gene is polymorphic at both DNA and protein level. The results suggest that the authors have identified a novel polymorphic gene family with multiple copies within the MHC. 48 refs., 10 figs., 2 tabs.

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...

MHC class II expression in lung cancer.

Science.gov (United States)

He, Yayi; Rozeboom, Leslie; Rivard, Christopher J; Ellison, Kim; Dziadziuszko, Rafal; Yu, Hui; Zhou, Caicun; Hirsch, Fred R

2017-10-01

Immunotherapy is an exciting development in lung cancer research. In this study we described major histocompatibility complex (MHC) Class II protein expression in lung cancer cell lines and patient tissues. We studied MHC Class II (DP, DQ, DR) (CR3/43, Abcam) protein expression in 55 non-small cell lung cancer (NSCLC) cell lines, 42 small cell lung cancer (SCLC) cell lines and 278 lung cancer patient tissues by immunohistochemistry (IHC). Seven (12.7%) NSCLC cell lines were positive for MHC Class II. No SCLC cell lines were found to be MHC Class II positive. We assessed 139 lung cancer samples available in the Hirsch Lab for MHC Class II. There was no positive MHC Class II staining on SCLC tumor cells. MHC Class II expression on TILs in SCLC was significantly lower than that on TILs in NSCLC (P＜0.001). MHC Class II was also assessed in an additional 139 NSCLC tumor tissues from Medical University of Gdansk, Poland. Patients with positive staining of MHC Class II on TILs had longer regression-free survival (RFS) and overall survival (OS) than those whose TILs were MHC Class II negative (2.980 years, 95% CI 1.628-4.332 vs. 1.050 years, 95% CI 0.556-1.554, P=0.028) (3.230 years, 95% CI 2.617-3.843 vs. 1.390 years, 95% CI 0.629-2.151, P=0.014). MHC Class II was expressed both in NSCLC cell lines and tissues. However, MHC Class II was not detected in SCLC cell lines or tissue tumor cells. MHC Class II expression was lower on SCLC TILs than on NSCLC TILs. Loss of expression of MHC Class II on SCLC tumor cells and reduced expression on SCLC TILs may be a means of escaping anti-cancer immunity. Higher MHC Class II expression on TILs was correlated with better prognosis in patients with NSCLC. Copyright © 2017. Published by Elsevier B.V.

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

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...... of different MHC data sets including human leukocyte antigen (HLA), non-human primates (chimpanzee, macaque and gorilla) and other animal alleles (cattle, mouse and swine). From these constructs, we showed that by focusing on MHC sequence positions found to be polymorphic across the MHC molecules used to train...

MHC variability in heritage breeds of chickens.

Science.gov (United States)

Fulton, J E; Lund, A R; McCarron, A M; Pinegar, K N; Korver, D R; Classen, H L; Aggrey, S; Utterbach, C; Anthony, N B; Berres, M E

2016-02-01

The chicken Major Histocompatibility Complex (MHC) is very strongly associated with disease resistance and thus is a very important region of the chicken genome. Historically, MHC (B locus) has been identified by the use of serology with haplotype specific alloantisera. These antisera can be difficult to produce and frequently cross-react with multiple haplotypes and hence their application is generally limited to inbred and MHC-defined lines. As a consequence, very little information about MHC variability in heritage chicken breeds is available. DNA-based methods are now available for examining MHC variability in these previously uncharacterized populations. A high density SNP panel consisting of 101 SNP that span a 230,000 bp region of the chicken MHC was used to examine MHC variability in 17 heritage populations of chickens from five universities from Canada and the United States. The breeds included 6 heritage broiler lines, 3 Barred Plymouth Rock, 2 New Hampshire and one each of Rhode Island Red, Light Sussex, White Leghorn, Dark Brown Leghorn, and 2 synthetic lines. These heritage breeds contained from one to 11 haplotypes per line. A total of 52 unique MHC haplotypes were found with only 10 of them identical to serologically defined haplotypes. Furthermore, nine MHC recombinants with their respective parental haplotypes were identified. This survey confirms the value of these non-commercially utilized lines in maintaining genetic diversity. The identification of multiple MHC haplotypes and novel MHC recombinants indicates that diversity is being generated and maintained within these heritage populations. © 2016 Poultry Science Association Inc.

MHC and Evolution in Teleosts

OpenAIRE

Grimholt, Unni

2016-01-01

Major histocompatibility complex (MHC) molecules are key players in initiating immune responses towards invading pathogens. Both MHC class I and class II genes are present in teleosts, and, using phylogenetic clustering, sequences from both classes have been classified into various lineages. The polymorphic and classical MHC class I and class II gene sequences belong to the U and A lineages, respectively. The remaining class I and class II lineages contain nonclassical gene sequences that, de...

Comparative genomic analysis of the MHC: the evolution of class I duplication blocks, diversity and complexity from shark to man.

Science.gov (United States)

Kulski, Jerzy K; Shiina, Takashi; Anzai, Tatsuya; Kohara, Sakae; Inoko, Hidetoshi

2002-12-01

The major histocompatibility complex (MHC) genomic region is composed of a group of linked genes involved functionally with the adaptive and innate immune systems. The class I and class II genes are intrinsic features of the MHC and have been found in all the jawed vertebrates studied so far. The MHC genomic regions of the human and the chicken (B locus) have been fully sequenced and mapped, and the mouse MHC sequence is almost finished. Information on the MHC genomic structures (size, complexity, genic and intergenic composition and organization, gene order and number) of other vertebrates is largely limited or nonexistent. Therefore, we are mapping, sequencing and analyzing the MHC genomic regions of different human haplotypes and at least eight nonhuman species. Here, we review our progress with these sequences and compare the human MHC structure with that of the nonhuman primates (chimpanzee and rhesus macaque), other mammals (pigs, mice and rats) and nonmammalian vertebrates such as birds (chicken and quail), bony fish (medaka, pufferfish and zebrafish) and cartilaginous fish (nurse shark). This comparison reveals a complex MHC structure for mammals and a relatively simpler design for nonmammalian animals with a hypothetical prototypic structure for the shark. In the mammalian MHC, there are two to five different class I duplication blocks embedded within a framework of conserved nonclass I and/or nonclass II genes. With a few exceptions, the class I framework genes are absent from the MHC of birds, bony fish and sharks. Comparative genomics of the MHC reveal a highly plastic region with major structural differences between the mammalian and nonmammalian vertebrates. Additional genomic data are needed on animals of the reptilia, crocodilia and marsupial classes to find the origins of the class I framework genes and examples of structures that may be intermediate between the simple and complex MHC organizations of birds and mammals, respectively.

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. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The SysteMHC Atlas project.

Science.gov (United States)

Shao, Wenguang; Pedrioli, Patrick G A; Wolski, Witold; Scurtescu, Cristian; Schmid, Emanuel; Vizcaíno, Juan A; Courcelles, Mathieu; Schuster, Heiko; Kowalewski, Daniel; Marino, Fabio; Arlehamn, Cecilia S L; Vaughan, Kerrie; Peters, Bjoern; Sette, Alessandro; Ottenhoff, Tom H M; Meijgaarden, Krista E; Nieuwenhuizen, Natalie; Kaufmann, Stefan H E; Schlapbach, Ralph; Castle, John C; Nesvizhskii, Alexey I; Nielsen, Morten; Deutsch, Eric W; Campbell, David S; Moritz, Robert L; Zubarev, Roman A; Ytterberg, Anders Jimmy; Purcell, Anthony W; Marcilla, Miguel; Paradela, Alberto; Wang, Qi; Costello, Catherine E; Ternette, Nicola; van Veelen, Peter A; van Els, Cécile A C M; Heck, Albert J R; de Souza, Gustavo A; Sollid, Ludvig M; Admon, Arie; Stevanovic, Stefan; Rammensee, Hans-Georg; Thibault, Pierre; Perreault, Claude; Bassani-Sternberg, Michal; Aebersold, Ruedi; Caron, Etienne

2018-01-04

Mass spectrometry (MS)-based immunopeptidomics investigates the repertoire of peptides presented at the cell surface by major histocompatibility complex (MHC) molecules. The broad clinical relevance of MHC-associated peptides, e.g. in precision medicine, provides a strong rationale for the large-scale generation of immunopeptidomic datasets and recent developments in MS-based peptide analysis technologies now support the generation of the required data. Importantly, the availability of diverse immunopeptidomic datasets has resulted in an increasing need to standardize, store and exchange this type of data to enable better collaborations among researchers, to advance the field more efficiently and to establish quality measures required for the meaningful comparison of datasets. Here we present the SysteMHC Atlas (https://systemhcatlas.org), a public database that aims at collecting, organizing, sharing, visualizing and exploring immunopeptidomic data generated by MS. The Atlas includes raw mass spectrometer output files collected from several laboratories around the globe, a catalog of context-specific datasets of MHC class I and class II peptides, standardized MHC allele-specific peptide spectral libraries consisting of consensus spectra calculated from repeat measurements of the same peptide sequence, and links to other proteomics and immunology databases. The SysteMHC Atlas project was created and will be further expanded using a uniform and open computational pipeline that controls the quality of peptide identifications and peptide annotations. Thus, the SysteMHC Atlas disseminates quality controlled immunopeptidomic information to the public domain and serves as a community resource toward the generation of a high-quality comprehensive map of the human immunopeptidome and the support of consistent measurement of immunopeptidomic sample cohorts. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Restriction fragment polymorphisms in the major histocompatibility complex of diabetic BB rats

DEFF Research Database (Denmark)

Kastern, W.; Dyrberg, T.; Scholler, J.

1984-01-01

DNA isolated from diabetic BB (BB/Hagedorn) rats was examined for restriction fragment length differences within the major histocompatibility complex (MHC) as compared with nondiabetic (W-subline) BB rats. Polymorphisms were detected using a mouse class I MHC gene as probe. Specifically, a 2-kb Bam......HI fragment was present in all the nondiabetic rats examined, but absent in the diabetic rats. Similar polymorphisms were observed with various other restriction enzymes, particularly XbaI, HindII, and SacI. There were no polymorphisms detected using either a human DR-alpha (class II antigen heavy chain...

Understanding TR binding to pMHC complexes: how does a TR scan many pMHC complexes yet preferentially bind to one.

Directory of Open Access Journals (Sweden)

Javed Mohammed Khan

Full Text Available Understanding the basis of the binding of a T cell receptor (TR to the peptide-MHC (pMHC complex is essential due to the vital role it plays in adaptive immune response. We describe the use of computed binding (free energy (BE, TR paratope, pMHC epitope, molecular surface electrostatic potential (MSEP and calculated TR docking angle (θ to analyse 61 TR/pMHC crystallographic structures to comprehend TR/pMHC interaction. In doing so, we have successfully demonstrated a novel/rational approach for θ calculation, obtained a linear correlation between BE and θ without any "codon" or amino acid preference, provided an explanation for TR ability to scan many pMHC ligands yet specifically bind one, proposed a mechanism for pMHC recognition by TR leading to T cell activation and illustrated the importance of the peptide in determining TR specificity, challenging the "germline bias" theory.

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.

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.

Autoimmunity in type 1 diabetes mellitus: a rat model

International Nuclear Information System (INIS)

Liu, Z.

1987-01-01

In this study, we have sought to isolate in vitro, from acutely diabetic BB rats, cytotoxic T lymphocytes, which exhibit specific cytotoxicity toward islet cells. Thoracic duct lymphocytes (TDL) from acutely diabetic BB rats cultured with irradiated MHC matched (RT1.u) islet cells and dendritic cells in vitro were shown to be specifically cytotoxic to MHC matched and mismatched allogeneic (RT1.1) and xenogeneic (hamster) islet target cells in a 3 H-leucine release assay. Two cell lines (V1A8 and V1D11) derived from the TDL culture showed similar patterns of non-MHC restricted islet cell killing which could be blocked by islet cells and cultured rat insulinoma cells (RIN5mF) but not by non-islet cells of various tissue origins. Both V1A8 and V1D11 were not cytotoxic to Natural Killer (NK) sensitive target cells, G1TC and YAC-1. Conventional surface markers for rat helper and suppressor/cytotoxic T cells were not detectable on either cell lines. The V1D11 cell line was positive for W 3/13 (rat T/NK marker) on OX-19 (rat T/macrophage marker), whereas the V1A8 cell line was only positive for W 3/13

Lassa fever

African Journals Online (AJOL)

ABEOLUGBENGAS

INTRODUCTION. Lassa virus is primarily transmitted by a (multimammate) rat specie Mastomys natalensis. The rat is the reservoir host for the virus. Humans get infected when the rodent's excreta contaminate food or other items within the house, the virus can spread secondarily from person to person (1). Most infections ...

The major histocompatibility complex genes impact pain response in DA and DA.1U rats.

Science.gov (United States)

Guo, Yuan; Yao, Fan-Rong; Cao, Dong-Yuan; Li, Li; Wang, Hui-Sheng; Xie, Wen; Zhao, Yan

2015-08-01

Our recent studies have shown that the difference in basal pain sensitivity to mechanical and thermal stimulation between Dark-Agouti (DA) rats and a novel congenic DA.1U rats is major histocompatibility complex (MHC) genes dependent. In the present study, we further used DA and DA.1U rats to investigate the role of MHC genes in formalin-induced pain model by behavioral, electrophysiological and immunohistochemical methods. Behavioral results showed biphasic nociceptive behaviors increased significantly following the intraplantar injection of formalin in the hindpaw of DA and DA.1U rats. The main nociceptive behaviors were lifting and licking, especially in DA rats (PDA rats were significantly higher than those in DA.1U rats in both phases of the formalin test (PDA rats was significantly higher than that of DA.1U rats (PDA was greater than that in DA.1U rats (PDA rats was significantly higher than that in DA.1U rats in the respective experimental group (PDA and DA.1U rats exhibited nociceptive responses in formalin-induced pain model and DA rats were more sensitive to noxious chemical stimulus than DA.1U rats, indicating that MHC genes might contribute to the difference in pain sensitivity. Copyright © 2015 Elsevier Inc. All rights reserved.

The local effect of octreotide on mechanical pain sensitivity is more sensitive in DA rats than DA.1U rats.

Science.gov (United States)

Yao, Fan-Rong; Wang, Hui-Sheng; Guo, Yuan; Zhao, Yan

2016-02-01

A recent study by the authors indicated that major histocompatibility complex (MHC) genes are associated with the differences in basal pain sensitivity and in formalin model between Dark-Agouti (DA) and novel congenic DA.1U rats, which have the same genetic background as DA rats except for the u alleles of MHC. The objective of the present study is to investigate whether there is a difference in the pristane-induced arthritis (PIA) model and local analgesic effect of octreotide (OCT) between DA and DA.1U rats. The hindpaw mechanical withdrawal threshold (MWT) and heat withdrawal latency (HWL) were observed. The C unit firings of the tibial nerve evoked by non-noxious and noxious toe movements were recorded by electrophysiological methods in normal and PIA models in DA and DA.1U rats before and after local OCT administration. The expression of somatostatin receptor 2A (SSTR2A) was observed by immunohistochemistry. The results demonstrate that DA rats have a higher mechanical sensitivity than DA.1U rats after PIA. Local OCT administration significantly elevated MWT in DA rats under normal and PIA sate, but not in DA.1U rats. The electrophysiological experiments showed OCT significantly attenuated the firings of C units evoked by non-noxious and noxious stimulation in DA rats more than those in DA.1U rats both in normal and PIA states. In addition, the expression of SSTR2A in the dorsal horn of the spinal cord was significantly higher in DA than in DA.1U rats. All of the findings suggest a higher local analgesic effect of OCT in DA rats than DA.1U rats, which might be associated with the MHC genes. © 2016 John Wiley & Sons Australia, Ltd.

NLRC5: a newly discovered MHC class I transactivator (CITA)

OpenAIRE

Meissner, Torsten B.; Li, Amy; Kobayashi, Koichi S.

2011-01-01

Major histocompatibility complex (MHC) class I and class II are crucial for the function of the human adaptive immune system. An NLR protein, CIITA (MHC class II transactivator), is a master regulator of MHC class II gene expression as well as of some of the genes involved in MHC class II antigen presentation. It has recently been discovered that another member of the NLR protein family, NLRC5, transcriptionally activates MHC class I genes, and thus acts as “CITA” (MHC class I transactivator)...

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.

Primordial linkage of β2-microglobulin to the MHC.

Science.gov (United States)

Ohta, Yuko; Shiina, Takashi; Lohr, Rebecca L; Hosomichi, Kazuyoshi; Pollin, Toni I; Heist, Edward J; Suzuki, Shingo; Inoko, Hidetoshi; Flajnik, Martin F

2011-03-15

β2-Microglobulin (β2M) is believed to have arisen in a basal jawed vertebrate (gnathostome) and is the essential L chain that associates with most MHC class I molecules. It contains a distinctive molecular structure called a constant-1 Ig superfamily domain, which is shared with other adaptive immune molecules including MHC class I and class II. Despite its structural similarity to class I and class II and its conserved function, β2M is encoded outside the MHC in all examined species from bony fish to mammals, but it is assumed to have translocated from its original location within the MHC early in gnathostome evolution. We screened a nurse shark bacterial artificial chromosome library and isolated clones containing β2M genes. A gene present in the MHC of all other vertebrates (ring3) was found in the bacterial artificial chromosome clone, and the close linkage of ring3 and β2M to MHC class I and class II genes was determined by single-strand conformational polymorphism and allele-specific PCR. This study satisfies the long-held conjecture that β2M was linked to the primordial MHC (Ur MHC); furthermore, the apparent stability of the shark genome may yield other genes predicted to have had a primordial association with the MHC specifically and with immunity in general.

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.

Thyroid hormone partially corrects the effect of diabetes on mysoin heavy chain RNAs in the rat ventricle

International Nuclear Information System (INIS)

Barrieux, A.; Dillmann, W.H.

1986-01-01

The relative abundance of the 2 cardiac myosin heavy chains (MHH-α and MHC-β) and their corresponding RNAs is similarly affected by hypothyroidism and diabetes in the rat ventricle. Since circulating levels of thyroid hormone (T 3 ) are significantly decreased in diabetes the decreased RNA-α and increased RNA-β associated with diabetes may be related to T 3 deficiency. Chronically diabetic rats were injected with T 3 , insulin (I), or both and sacrificed between 1 and 12 hrs after injection, MHC RNA was quantified by hybridization of total RNA to a [ 32 P]-cDNA MHC-α probe. Total MHC RNA was measured by retention of S1-resistant label on DE-81 while RNA-α and RNA-β were quantified by separation of intact (α) and partially digested (β) probe by gel electrophoresis. Total MHC RNA was not changed by T 3 or I (.9-1.2 ng/μg of cellular RNA). T 3 and I elicited a very rapid increase in RNA-α (18% in untreated to 38% (I) and 47% (T 3 within 1 hr). I administered either 7 hr before or 1 hr after T 3 did not modify the RNA-α increase observed after T 3 alone. However, the response of diabetic rats to T 3 was markedly different from that of hypothyroid rats. Conclusions: 1) T 3 in diabetic rats does not mimick the effect of T 3 in hypothyroid rats; it may simply impose a hyperthyroid state on the existing diabetes and 2) since neither T 3 nor I are able to increase RNA-α to control levels within 12 hrs, neither hormone is sufficient to regulate the expression of MHC RNAs

Isomyosin expression patterns during rat heart morphogenesis: an immunohistochemical study

NARCIS (Netherlands)

de Groot, I. J.; Lamers, W. H.; Moorman, A. F.

1989-01-01

An immunohistochemical study of cardiac alpha and beta myosin heavy chain (MHC) expression during rat heart morphogenesis was performed. In tubular hearts (embryonic days, ED10-11) coexpression of both cardiac alpha and beta MHC was found throughout the heart, except for the left free wall of the

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...

Methods for MHC genotyping in non-model vertebrates.

Science.gov (United States)

Babik, W

2010-03-01

Genes of the major histocompatibility complex (MHC) are considered a paradigm of adaptive evolution at the molecular level and as such are frequently investigated by evolutionary biologists and ecologists. Accurate genotyping is essential for understanding of the role that MHC variation plays in natural populations, but may be extremely challenging. Here, I discuss the DNA-based methods currently used for genotyping MHC in non-model vertebrates, as well as techniques likely to find widespread use in the future. I also highlight the aspects of MHC structure that are relevant for genotyping, and detail the challenges posed by the complex genomic organization and high sequence variation of MHC loci. Special emphasis is placed on designing appropriate PCR primers, accounting for artefacts and the problem of genotyping alleles from multiple, co-amplifying loci, a strategy which is frequently necessary due to the structure of the MHC. The suitability of typing techniques is compared in various research situations, strategies for efficient genotyping are discussed and areas of likely progress in future are identified. This review addresses the well established typing methods such as the Single Strand Conformation Polymorphism (SSCP), Denaturing Gradient Gel Electrophoresis (DGGE), Reference Strand Conformational Analysis (RSCA) and cloning of PCR products. In addition, it includes the intriguing possibility of direct amplicon sequencing followed by the computational inference of alleles and also next generation sequencing (NGS) technologies; the latter technique may, in the future, find widespread use in typing complex multilocus MHC systems. © 2009 Blackwell Publishing Ltd.

Prediction of antigenic epitopes and MHC binders of neurotoxin ...

African Journals Online (AJOL)

PRECIOUS

2009-12-01

Dec 1, 2009 ... scorpion chlorotoxin-like short-chain neurotoxins (SCNs). *Corresponding ... Protein sequence analysis. Here we ... MHC/peptide binding is a log-transformed value related to the IC50 values in nM ..... porter. Adducts of MHC and peptide complexes are the ligands for T cell receptors (TCR) (Table-1). MHC.

Sympatric and allopatric divergence of MHC genes in threespine stickleback.

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Blake Matthews

2010-06-01

Full Text Available Parasites can strongly affect the evolution of their hosts, but their effects on host diversification are less clear. In theory, contrasting parasite communities in different foraging habitats could generate divergent selection on hosts and promote ecological speciation. Immune systems are costly to maintain, adaptable, and an important component of individual fitness. As a result, immune system genes, such as those of the Major Histocompatibility Complex (MHC, can change rapidly in response to parasite-mediated selection. In threespine stickleback (Gasterosteus aculeatus, as well as in other vertebrates, MHC genes have been linked with female mating preference, suggesting that divergent selection acting on MHC genes might influence speciation. Here, we examined genetic variation at MHC Class II loci of sticklebacks from two lakes with a limnetic and benthic species pair, and two lakes with a single species. In both lakes with species pairs, limnetics and benthics differed in their composition of MHC alleles, and limnetics had fewer MHC alleles per individual than benthics. Similar to the limnetics, the allopatric population with a pelagic phenotype had few MHC alleles per individual, suggesting a correlation between MHC genotype and foraging habitat. Using a simulation model we show that the diversity and composition of MHC alleles in a sympatric species pair depends on the amount of assortative mating and on the strength of parasite-mediated selection in adjacent foraging habitats. Our results indicate parallel divergence in the number of MHC alleles between sympatric stickleback species, possibly resulting from the contrasting parasite communities in littoral and pelagic habitats of lakes.

MHCcluster, a method for functional clustering of MHC molecules

DEFF Research Database (Denmark)

Thomsen, Martin Christen Frølund; Lundegaard, Claus; Buus, Søren

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...... 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...

Concurrent hippocampal induction of MHC II pathway components and glial activation with advanced aging is not correlated with cognitive impairment

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Sonntag William E

2011-10-01

Full Text Available Abstract Background Age-related cognitive dysfunction, including impairment of hippocampus-dependent spatial learning and memory, affects approximately half of the aged population. Induction of a variety of neuroinflammatory measures has been reported with brain aging but the relationship between neuroinflammation and cognitive decline with non-neurodegenerative, normative aging remains largely unexplored. This study sought to comprehensively investigate expression of the MHC II immune response pathway and glial activation in the hippocampus in the context of both aging and age-related cognitive decline. Methods Three independent cohorts of adult (12-13 months and aged (26-28 months F344xBN rats were behaviorally characterized by Morris water maze testing. Expression of MHC II pathway-associated genes identified by transcriptomic analysis as upregulated with advanced aging was quantified by qPCR in synaptosomal fractions derived from whole hippocampus and in hippocampal subregion dissections (CA1, CA3, and DG. Activation of astrocytes and microglia was assessed by GFAP and Iba1 protein expression, and by immunohistochemical visualization of GFAP and both CD74 (Ox6 and Iba1. Results We report a marked age-related induction of neuroinflammatory signaling transcripts (i.e., MHC II components, toll-like receptors, complement, and downstream signaling factors throughout the hippocampus in all aged rats regardless of cognitive status. Astrocyte and microglial activation was evident in CA1, CA3 and DG of intact and impaired aged rat groups, in the absence of differences in total numbers of GFAP+ astrocytes or Iba1+ microglia. Both mild and moderate microglial activation was significantly increased in all three hippocampal subregions in aged cognitively intact and cognitively impaired rats compared to adults. Neither induction of MHCII pathway gene expression nor glial activation correlated to cognitive performance. Conclusions These data demonstrate a

Simulation of Major Histocompatibility Complex (MHC Structure and Peptide Loading into an MHC Binding Pocket with Teachers’Hands

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Mojtaba Sankian

2013-10-01

Full Text Available Molecular understanding of three-dimensional (3D peptide: MHC models require both basic knowledge of computational modeling and skilled visual perception, which are not possessed by all students. The present model aims to simulate MHC molecular structure with the hands and make a profound impression on the students.

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.

Complex Mhc-based mate choice in a wild passerine

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Bonneaud, Camille; Chastel, Olivier; Federici, Pierre; Westerdahl, Helena; Sorci, Gabriele

2006-01-01

The extreme polymorphism of the vertebrate major histocompatibility complex (Mhc) is famous for protecting hosts against constantly evolving pathogens. Mate choice is often evoked as a means of maintaining Mhc variability through avoidance of partners with similar Mhc alleles or preference for heterozygotes. Evidence for these two hypotheses mostly comes from studies on humans and laboratory mice. Here, we tested these hypotheses in a wild outbred population of house sparrows (Passer domesticus). Females were not more or less closely related to the males they paired with when considering neutral genetic variation. However, males failed to form breeding pairs when they had too few Mhc alleles and when they were too dissimilar from females at Mhc loci (i.e. had no common alleles). Furthermore, pairs did not form at random as Mhc diversity positively correlated in mating pairs. These results suggest that mate choice evolves in response to (i) benefits in terms of parasite resistance acquired from allelic diversity, and (ii) costs associated with the disruption of co-adapted genes. PMID:16600889

High levels of diversity characterize mandrill (Mandrillus sphinx) Mhc-DRB sequences.

Science.gov (United States)

Abbott, Kristin M; Wickings, E Jean; Knapp, Leslie A

2006-08-01

The major histocompatibility complex (MHC) is highly polymorphic in most primate species studied thus far. The rhesus macaque (Macaca mulatta) has been studied extensively and the Mhc-DRB region demonstrates variability similar to humans. The extent of MHC diversity is relatively unknown for other Old World monkeys (OWM), especially among genera other than Macaca. A molecular survey of the Mhc-DRB region in mandrills (Mandrillus sphinx) revealed extensive variability, suggesting that other OWMs may also possess high levels of Mhc-DRB polymorphism. In the present study, 33 Mhc-DRB loci were identified from only 13 animals. Eleven were wild-born and presumed to be unrelated and two were captive-born twins. Two to seven different sequences were identified for each individual, suggesting that some mandrills may have as many as four Mhc-DRB loci on a single haplotype. From these sequences, representatives of at least six Mhc-DRB loci or lineages were identified. As observed in other primates, some new lineages may have arisen through the process of gene conversion. These findings indicate that mandrills have Mhc-DRB diversity not unlike rhesus macaques and humans.

An integrated tool to study MHC region: accurate SNV detection and HLA genes typing in human MHC region using targeted high-throughput sequencing.

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Hongzhi Cao

Full Text Available The major histocompatibility complex (MHC is one of the most variable and gene-dense regions of the human genome. Most studies of the MHC, and associated regions, focus on minor variants and HLA typing, many of which have been demonstrated to be associated with human disease susceptibility and metabolic pathways. However, the detection of variants in the MHC region, and diagnostic HLA typing, still lacks a coherent, standardized, cost effective and high coverage protocol of clinical quality and reliability. In this paper, we presented such a method for the accurate detection of minor variants and HLA types in the human MHC region, using high-throughput, high-coverage sequencing of target regions. A probe set was designed to template upon the 8 annotated human MHC haplotypes, and to encompass the 5 megabases (Mb of the extended MHC region. We deployed our probes upon three, genetically diverse human samples for probe set evaluation, and sequencing data show that ∼97% of the MHC region, and over 99% of the genes in MHC region, are covered with sufficient depth and good evenness. 98% of genotypes called by this capture sequencing prove consistent with established HapMap genotypes. We have concurrently developed a one-step pipeline for calling any HLA type referenced in the IMGT/HLA database from this target capture sequencing data, which shows over 96% typing accuracy when deployed at 4 digital resolution. This cost-effective and highly accurate approach for variant detection and HLA typing in the MHC region may lend further insight into immune-mediated diseases studies, and may find clinical utility in transplantation medicine research. This one-step pipeline is released for general evaluation and use by the scientific community.

Time course of myosin heavy chain transitions in neonatal rats: importance of innervation and thyroid state

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Adams, G. R.; McCue, S. A.; Zeng, M.; Baldwin, K. M.

1999-01-01

During the postnatal period, rat limb muscles adapt to weight bearing via the replacement of embryonic (Emb) and neonatal (Neo) myosin heavy chains (MHCs) by the adult isoforms. Our aim was to characterize this transition in terms of the six MHC isoforms expressed in skeletal muscle and to determine the importance of innervation and thyroid hormone status on the attainment of the adult MHC phenotype. Neonatal rats were made hypothyroid via propylthiouracil (PTU) injection. In normal and PTU subgroups, leg muscles were unilaterally denervated at 15 days of age. The MHC profiles of plantaris (PLN) and soleus (Sol) muscles were determined at 7, 14, 23, and 30 days postpartum. At day 7, the Sol MHC profile was 55% type I, 30% Emb, and 10% Neo; in the PLN, the pattern was 60% Neo and 25% Emb. By day 30 the Sol and PLN had essentially attained an adult MHC profile in the controls. PTU augmented slow MHC expression in the Sol, whereas in the PLN it markedly repressed IIb MHC by retaining neonatal MHC expression. Denervation blunted the upregulation of IIb in the PLN and of Type I in the Sol and shifted the pattern to greater expression of IIa and IIx MHCs in both muscles. In contrast to previous observations, these findings collectively suggest that both an intact thyroid and innervation state are obligatory for the attainment of the adult MHC phenotype, particularly in fast-twitch muscles.

ER stress affects processing of MHC class I-associated peptides

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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.

Role of major histocompatibility complex class II in the development of autoimmune type 1 diabetes and thyroiditis in rats

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Yokoi, N; Hidaka, S; Tanabe, S; Ohya, M; Ishima, M; Takagi, Y; Masui, N; Seino, S

2012-01-01

Although the MHC class II ‘u' haplotype is strongly associated with type 1 diabetes (T1D) in rats, the role of MHC class II in the development of tissue-specific autoimmune diseases including T1D and autoimmune thyroiditis remains unclear. To clarify this, we produced a congenic strain carrying MHC class II ‘a' and ‘u' haplotypes on the Komeda diabetes-prone (KDP) genetic background. The u/u homozygous animals developed T1D similar to the original KDP rat; a/u heterozygous animals did develop T1D but with delayed onset and low frequency. In contrast, none of the a/a homozygous animals developed T1D; about half of the animals with a/u heterozygous or a/a homozygous genotypes showed autoimmune thyroiditis. To investigate the role of genetic background in the development of thyroiditis, we also produced a congenic strain carrying Cblb mutation of the KDP rat on the PVG.R23 genetic background (MHC class II ‘a' haplotype). The congenic rats with homozygous Cblb mutation showed autoimmune thyroiditis without T1D and slight to severe alopecia, a clinical symptom of hypothyroidism such as Hashimoto's thyroiditis. These data indicate that MHC class II is involved in the tissue-specific development of autoimmune diseases, including T1D and thyroiditis. PMID:21918539

NLRC5: a key regulator of MHC class I-dependent immune responses.

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Kobayashi, Koichi S; van den Elsen, Peter J

2012-12-01

The expression of MHC class I molecules is crucial for the initiation and regulation of adaptive immune responses against pathogens. NOD-, LRR- and CARD-containing 5 (NLRC5) was recently identified as a specific transactivator of MHC class I genes (CITA). NLRC5 and the master regulator for MHC class II genes, class II transactivator (CIITA), interact with similar MHC promoter-bound factors. Here, we provide a broad overview of the molecular mechanisms behind MHC class I transcription and the role of the class I transactivator NLRC5 in MHC class I-dependent immune responses.

C57BL/6 mice need MHC class II Aq to develop collagen-induced arthritis dependent on autoreactive T cells.

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Bäcklund, Johan; Li, Cuiqin; Jansson, Erik; Carlsen, Stefan; Merky, Patrick; Nandakumar, Kutty-Selva; Haag, Sabrina; Ytterberg, Jimmy; Zubarev, Roman A; Holmdahl, Rikard

2013-07-01

Collagen-induced arthritis (CIA) has traditionally been performed in MHC class II A(q)-expressing mice, whereas most genetically modified mice are on the C57BL/6 background (expressing the b haplotype of the major histocompatibility complex (MHC) class II region). However, C57BL/6 mice develop arthritis after immunisation with chicken-derived collagen type II (CII), but arthritis susceptibility has been variable, and the immune specificity has not been clarified. To establish a CIA model on the C57BL/6 background with a more predictable and defined immune response to CII. Both chicken and rat CII were arthritogenic in C57BL/6 mice provided they were introduced with high doses of Mycobacterium tuberculosis adjuvant. However, contaminating pepsin was strongly immunogenic and was essential for arthritis development. H-2(b)-restricted T cell epitopes on chicken or rat CII could not be identified, but expression of A(q) on the C57BL/6 background induced T cell response to the CII260-270 epitope, and also prolonged the arthritis to be more chronic. The putative (auto)antigen and its arthritogenic determinants in C57BL/6 mice remains undisclosed, questioning the value of the model for addressing T cell-driven pathological pathways in arthritis. To circumvent this impediment, we recommend MHC class II congenic C57BL/6N.Q mice, expressing A(q), with which T cell determinants have been thoroughly characterised.

A hybrid approach for predicting promiscuous MHC class I restricted ...

Indian Academy of Sciences (India)

Prakash

2006-09-15

Sep 15, 2006 ... with existing MHC binder prediction methods for alleles studied by both ... in locating the promiscuous MHC binding regions from antigen sequence. ... Artificial neural network; MHC class I alleles; promiscuous binders; ... this problem by developing methods for prediction for ... In case equal number of.

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

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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.

The C-terminal amino acid of the MHC-I heavy chain is critical for binding to Derlin-1 in human cytomegalovirus US11-induced MHC-I degradation.

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Cho, Sunglim; Kim, Bo Young; Ahn, Kwangseog; Jun, Youngsoo

2013-01-01

Derlin-1 plays a critical role in endoplasmic reticulum-associated protein degradation (ERAD) of a particular subset of proteins. Although it is generally accepted that Derlin-1 mediates the export of ERAD substrates from the ER to the cytosol, little is known about how Derlin-1 interacts with these substrates. Human cytomegalovirus (HCMV) US11 exploits Derlin-1-dependent ERAD to degrade major histocompatibility complex class I (MHC-I) molecules and evade immune surveillance. US11 requires the cytosolic tail of the MHC-I heavy chain to divert MHC-I molecules into the ERAD pathway for degradation; however, the underlying mechanisms remain unknown. Here, we show that the cytosolic tail of the MHC-I heavy chain, although not required for interaction with US11, is required for tight binding to Derlin-1 and thus for US11-induced dislocation of the MHC-I heavy chain to the cytosol for proteasomal degradation. Surprisingly, deletion of a single C-terminal amino acid from the cytosolic tail disrupted the interaction between MHC-I molecules and Derlin-1, rendering mutant MHC-I molecules resistant to US11-induced degradation. Consistently, deleting the C-terminal cytosolic region of Derlin-1 prevented it from binding to MHC-I molecules. Taken together, these results suggest that the cytosolic region of Derlin-1 is involved in ERAD substrate binding and that this interaction is critical for the Derlin-1-mediated dislocation of the MHC-I heavy chain to the cytosol during US11-induced MHC-I degradation.

MHC Intratumoral Heterogeneity May Predict Cancer Progression and Response to Immunotherapy

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Irene Romero

2018-01-01

Full Text Available An individual tumor can present intratumoral phenotypic heterogeneity, containing tumor cells with different phenotypes that do not present irreversible genetic alterations. We have developed a mouse cancer model, named GR9, derived from a methylcholanthrene-induced fibrosarcoma that was adapted to tissue culture and cloned into different tumor cell lines. The clones showed diverse MHC-I phenotypes, ranging from highly positive to weakly positive MHC-I expression. These MHC-I alterations are due to reversible molecular mechanisms, because surface MHC-I could be recovered by IFN-γ treatment. Cell clones with high MHC-I expression demonstrated low local oncogenicity and high spontaneous metastatic capacity, whereas MHC-I-low clones showed high local oncogenicity and no spontaneous metastatic capacity. Although MHC-I-low clones did not metastasize, they produced MHC-I-positive dormant micrometastases controlled by the host immune system, i.e., in a state of immunodormancy. The metastatic capacity of each clone was directly correlated with the host T-cell subpopulations; thus, a strong decrease in cytotoxic and helper T lymphocytes was observed in mice with numerous metastases derived from MHC-I positive tumor clones but a strong increase was observed in those with dormant micrometastases. Immunotherapy was administered to the hosts after excision of the primary tumor, producing a recovery in their immune status and leading to the complete eradication of overt spontaneous metastases or their decrease. According to these findings, the combination of MHC-I surface expression in primary tumor and metastases with host T-cell subsets may be a decisive indicator of the clinical outcome and response to immunotherapy in metastatic disease, allowing the identification of responders to this approach.

natalensis (Muridae: Rodentia)

African Journals Online (AJOL)

2011-04-07

Apr 7, 2011 ... Mastomys natalensis, the multimammate mouse, was live-trapped on six grids varying in vegetative cover and ... induced cotton rats to occupy open patches which. without ... The presenL study was designed to test experimentally the ..... Swanepoel 1980; Monadjem 1997b) and insects (Field 1975).

Fine-mapping analysis of the MHC region for vitiligo based on a new Han-MHC reference panel.

Science.gov (United States)

Yang, Chao; Wu, Juan; Zhang, Xuelei; Wen, Leilei; Sun, Jingying; Cheng, Yuyan; Tang, Xianfa; Liang, Bo; Chen, Gang; Zhou, Fusheng; Cui, Yong; Zhang, Anping; Zhang, Xuejun; Zheng, Xiaodong; Yang, Sen; Sun, Liangdan

2018-03-30

Vitiligo is an immune-related disease with patchy depigmentation of skin and hair caused by selective destruction of melanocytes. In recent decades, many studies have shown the association between vitiligo and HLA genes; however, the results of Han Chinese are scarce. In this study, we performed a fine-mapping analysis of the MHC region in 2818 Han Chinese subjects through a widely used HLA imputation method with a newly built large-scale Han-MHC reference panel. Three new four-digit HLA alleles (HLA-DQB1 ∗ 02:02, HLA-DQA1 ∗ 02:01 and HLA-DPB1 ∗ 17:01) were identified to be associated with the risk of vitiligo, and four previously reported alleles were confirmed. Further conditional analysis revealed that two important variants, HLA-DQβ1 amino acid position 135 (OR = 1.79, P = 1.87 × 10 -11 ) and HLA-B amino acid positions 45-46 (OR = 1.44, P = 5.61 × 10 -11 ), conferred most of the MHC associations. Three-dimension ribbon models showed that the former is located within the β2 domain of the HLA-DQβ1 molecule, and the latter lies in the α1 domain of the HLA-B molecule, while both are involved in specific antigen presenting process. Finally, we summarized all significant signals in the MHC region to clarify their complex relationships, and 8.60% of phenotypic variance could be explained based on all reported variants in Han Chinese so far. Our findings highlight the complex genetic architecture of the MHC region for vitiligo in Han Chinese population and expand our understanding of the roles of HLA coding variants in the etiology of vitiligo. Copyright © 2018. Published by Elsevier B.V.

Virus encoded MHC-like decoys diversify the inhibitory KIR repertoire.

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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.

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

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

Cheetah paradigm revisited: MHC diversity in the world's largest free-ranging population.

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Castro-Prieto, Aines; Wachter, Bettina; Sommer, Simone

2011-04-01

For more than two decades, the cheetah (Acinonyx jubatus) has been considered a paradigm of disease vulnerability associated with low genetic diversity, particularly at the immune genes of the major histocompatibility complex (MHC). Cheetahs have been used as a classic example in numerous conservation genetics textbooks as well as in many related scientific publications. However, earlier studies used methods with low resolution to quantify MHC diversity and/or small sample sizes. Furthermore, high disease susceptibility was reported only for captive cheetahs, whereas free-ranging cheetahs show no signs of infectious diseases and a good general health status. We examined whether the diversity at MHC class I and class II-DRB loci in 149 Namibian cheetahs was higher than previously reported using single-strand conformation polymorphism analysis, cloning, and sequencing. MHC genes were examined at the genomic and transcriptomic levels. We detected ten MHC class I and four class II-DRB alleles, of which nine MHC class I and all class II-DRB alleles were expressed. Phylogenetic analyses and individual genotypes suggested that the alleles belong to four MHC class I and three class II-DRB putative loci. Evidence of positive selection was detected in both MHC loci. Our study indicated that the low number of MHC class I alleles previously observed in cheetahs was due to a smaller sample size examined. On the other hand, the low number of MHC class II-DRB alleles previously observed in cheetahs was further confirmed. Compared with other mammalian species including felids, cheetahs showed low levels of MHC diversity, but this does not seem to influence the immunocompetence of free-ranging cheetahs in Namibia and contradicts the previous conclusion that the cheetah is a paradigm species of disease vulnerability.

Sex-specific selection for MHC variability in Alpine chamois

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Schaschl Helmut

2012-02-01

Full Text Available Abstract Background In mammals, males typically have shorter lives than females. This difference is thought to be due to behavioural traits which enhance competitive abilities, and hence male reproductive success, but impair survival. Furthermore, in many species males usually show higher parasite burden than females. Consequently, the intensity of selection for genetic factors which reduce susceptibility to pathogens may differ between sexes. High variability at the major histocompatibility complex (MHC genes is believed to be advantageous for detecting and combating the range of infectious agents present in the environment. Increased heterozygosity at these immune genes is expected to be important for individual longevity. However, whether males in natural populations benefit more from MHC heterozygosity than females has rarely been investigated. We investigated this question in a long-term study of free-living Alpine chamois (Rupicapra rupicapra, a polygynous mountain ungulate. Results Here we show that male chamois survive significantly (P = 0.022 longer if heterozygous at the MHC class II DRB locus, whereas females do not. Improved survival of males was not a result of heterozygote advantage per se, as background heterozygosity (estimated across twelve microsatellite loci did not change significantly with age. Furthermore, reproductively active males depleted their body fat reserves earlier than females leading to significantly impaired survival rates in this sex (P Conclusions Increased MHC class II DRB heterozygosity with age in males, suggests that MHC heterozygous males survive longer than homozygotes. Reproductively active males appear to be less likely to survive than females most likely because of the energetic challenge of the winter rut, accompanied by earlier depletion of their body fat stores, and a generally higher parasite burden. This scenario renders the MHC-mediated immune response more important for males than for females

MHC class II polymorphisms, autoreactive T-cells and autoimmunity

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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.

Semi-empirical quantum evaluation of peptide - MHC class II binding

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González, Ronald; Suárez, Carlos F.; Bohórquez, Hugo J.; Patarroyo, Manuel A.; Patarroyo, Manuel E.

2017-01-01

Peptide presentation by the major histocompatibility complex (MHC) is a key process for triggering a specific immune response. Studying peptide-MHC (pMHC) binding from a structural-based approach has potential for reducing the costs of investigation into vaccine development. This study involved using two semi-empirical quantum chemistry methods (PM7 and FMO-DFTB) for computing the binding energies of peptides bonded to HLA-DR1 and HLA-DR2. We found that key stabilising water molecules involved in the peptide binding mechanism were required for finding high correlation with IC50 experimental values. Our proposal is computationally non-intensive, and is a reliable alternative for studying pMHC binding interactions.

MHC class II+ (HLA-DP-like) cells in the cow reproductive tract: II. Immunolocalization of MHC class II+ cells in oviduct and vagina.

Science.gov (United States)

Eren, U; Kum, S; Sandikçi, M; Eren, V; Ilhan, F

2009-08-01

The aim of this study was to determine and examine the distribution of major frequency MHC II+ cells in the oviduct and vagina of cows during the oestrous and dioestrus phases. Right oviduct (ampulla, isthmus) and vaginal samples taken from a total of twenty seven multiparous cows were used. Tissue samples were processed to obtain both cryostat and paraffin sections. Sections were stained immunocytochemically using StreptABC method using a specific monoclonal antibody to MHC II+ cell population. Intra-epithelial and subepithelial areas along with lamina propria, muscularis mucosae and serosa of both ampulla and isthmus and intra-epithelial/subepithelial areas and mucosae of vagina were examined for the presence of MHC II+ cells. The density of immune positive cells was determined using a subjective scoring system. MHC II+ cells were demonstrated in all areas examined in both oestrus and dioestrus. In oestrus, the density of MHC II+ cells decreased in subepithelial areas (in between the epithelial cells and the basal membrane) of isthmus, whereas the density of immune positive cells was increased in muscularis mucosae of isthmus (P < 0.05), lamina propria and muscularis mucosae of ampulla (P < 0.05) as well as in the mucosae of vagina (P MHC II+ cells observed in the oviduct and vagina increases in the majority of areas examined due to the effect of oestrogen.

Polymorphism at Expressed DQ and DR Loci in Five Common Equine MHC Haplotypes

Science.gov (United States)

Miller, Donald; Tallmadge, Rebecca L.; Binns, Matthew; Zhu, Baoli; Mohamoud, Yasmin Ali; Ahmed, Ayeda; Brooks, Samantha A.; Antczak, Douglas F.

2016-01-01

The polymorphism of Major Histocompatibility Complex (MHC) class II DQ and DR genes in five common Equine Leukocyte Antigen (ELA) haplotypes was determined through sequencing of mRNA transcripts isolated from lymphocytes of eight ELA homozygous horses. Ten expressed MHC class II genes were detected in horses of the ELA-A3 haplotype carried by the donor horses of the equine Bacterial Artificial Chromosome (BAC) library and the reference genome sequence: four DR genes and six DQ genes. The other four ELA haplotypes contained at least eight expressed polymorphic MHC class II loci. Next Generation Sequencing (NGS) of genomic DNA of these four MHC haplotypes revealed stop codons in the DQA3 gene in the ELA-A2, ELA-A5, and ELA-A9 haplotypes. Few NGS reads were obtained for the other MHC class II genes that were not amplified in these horses. The amino acid sequences across haplotypes contained locus-specific residues, and the locus clusters produced by phylogenetic analysis were well supported. The MHC class II alleles within the five tested haplotypes were largely non-overlapping between haplotypes. The complement of equine MHC class II DQ and DR genes appears to be well conserved between haplotypes, in contrast to the recently described variation in class I gene loci between equine MHC haplotypes. The identification of allelic series of equine MHC class II loci will aid comparative studies of mammalian MHC conservation and evolution and may also help to interpret associations between the equine MHC class II region and diseases of the horse. PMID:27889800

MHC class II deficiency: Report of a novel mutation and special review.

Science.gov (United States)

Farrokhi, S; Shabani, M; Aryan, Z; Zoghi, S; Krolo, A; Boztug, K; Rezaei, N

The MHC II deficiency is a rare autosomal recessive primary immunodeficiency syndrome with increased susceptibility to respiratory and gastrointestinal infections, failure to thrive and early mortality. This syndrome is caused by mutations in transcription regulators of the MHC II gene and results in development of blind lymphocytes due to the lack of indicatory MHC II molecules. Despite homogeneity of clinical manifestations of patients with MHC II deficiency, the genetic defects underlying this disease are heterogeneous. Herein, we report an Iranian patient with MHC II deficiency harbouring a novel mutation in RFXANK and novel misleading clinical features. He had ataxic gait and dysarthria from 30 months of age. Epidemiology, clinical and immunological features, therapeutic options and prognosis of patients with MHC II are reviewed in this paper. Copyright © 2017 SEICAP. Published by Elsevier España, S.L.U. All rights reserved.

The systems biology of MHC class II antigen presentation

NARCIS (Netherlands)

Paul, Petra

2012-01-01

Major histocompatibility class II molecules (MHC class II) are one of the key regulators of adaptive immunity because of their specific expression by professional antigen presenting cells (APC). They present peptides derived from endocytosed material to T helper lymphocytes. Consequently, MHC class

MHC2NNZ: A novel peptide binding prediction approach for HLA DQ molecules

Science.gov (United States)

Xie, Jiang; Zeng, Xu; Lu, Dongfang; Liu, Zhixiang; Wang, Jiao

2017-07-01

The major histocompatibility complex class II (MHC-II) molecule plays a crucial role in immunology. Computational prediction of MHC-II binding peptides can help researchers understand the mechanism of immune systems and design vaccines. Most of the prediction algorithms for MHC-II to date have made large efforts in human leukocyte antigen (HLA, the name of MHC in Human) molecules encoded in the DR locus. However, HLA DQ molecules are equally important and have only been made less progress because it is more difficult to handle them experimentally. In this study, we propose an artificial neural network-based approach called MHC2NNZ to predict peptides binding to HLA DQ molecules. Unlike previous artificial neural network-based methods, MHC2NNZ not only considers sequence similarity features but also captures the chemical and physical properties, and a novel method incorporating these properties is proposed to represent peptide flanking regions (PFR). Furthermore, MHC2NNZ improves the prediction accuracy by combining with amino acid preference at more specific positions of the peptides binding core. By evaluating on 3549 peptides binding to six most frequent HLA DQ molecules, MHC2NNZ is demonstrated to outperform other state-of-the-art MHC-II prediction methods.

Structure and expression of MHC class Ib genes of the central M region in rat and mouse: M4, M5, and M6.

Science.gov (United States)

Lambracht-Washington, Doris; Moore, Yuki F; Wonigeit, Kurt; Lindahl, Kirsten Fischer

2008-04-01

The M region at the telomeric end of the murine major histocompatibility complex (MHC) contains class I genes that are highly conserved in rat and mouse. We have sequenced a cosmid clone of the LEW rat strain (RT1 haplotype) containing three class I genes, RT1.M6-1, RT1.M4, and RT1.M5. The sequences of allelic genes of the BN strain (RT1n haplotype) were obtained either from cDNAs or genomic clones. For the coding parts of the genes few differences were found between the two RT1 haplotypes. In LEW, however, only RT1.M5 and RT1.M6 have open reading frames; whereas in BN all three genes were intact. In line with the findings in BN, transcription was found for all three rat genes in several tissues from strain Sprague Dawley. Protein expression in transfectants could be demonstrated for RT1.M6-1 using the monoclonal antibody OX18. By sequencing of transcripts obtained by RT-PCR, a second, transcribed M6 gene, RT1.M6-2, was discovered, which maps next to RT1.M6-1 outside of the region covered by the cosmid. In addition, alternatively spliced forms for RT1.M5 and RT1.M6 were detected. Of the orthologous mouse genes, H2-M4, H2-M5, and H2-M6, only H2-M5 has an open reading frame. Other important differences between the corresponding parts of the M region of the two species are insertion of long LINE repeats, duplication of RT1.M6, and the inversion of RT1.M5 in the rat. This demonstrates substantial evolutionary dynamics in this region despite conservation of the class I gene sequences themselves.

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...

An MHC class I immune evasion gene of Marek׳s disease virus.

Science.gov (United States)

Hearn, Cari; Preeyanon, Likit; Hunt, Henry D; York, Ian A

2015-01-15

Marek׳s disease virus (MDV) is a widespread α-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 we demonstrate that an MDV gene, MDV012, is capable of reducing surface expression of MHC class I on chicken cells. Co-expression of an MHC class I-binding peptide targeted to the endoplasmic reticulum (bypassing the requirement for the TAP peptide transporter) partially rescued MHC class I expression in the presence of MDV012, suggesting that MDV012 is a TAP-blocking MHC class I immune evasion protein. This is the first unique non-mammalian MHC class I immune evasion gene identified, and suggests that α-herpesviruses have conserved this function for at least 100 million years. Copyright © 2014 Elsevier Inc. All rights reserved.

A Genome-wide multidimensional RNAi screen reveals pathways controlling MHC class II antigen presentation

NARCIS (Netherlands)

Paul, Petra; van den Hoorn, Tineke; Jongsma, Marlieke L. M.; Bakker, Mark J.; Hengeveld, Rutger; Janssen, Lennert; Cresswell, Peter; Egan, David A.; van Ham, Marieke; ten Brinke, Anja; Ovaa, Huib; Beijersbergen, Roderick L.; Kuijl, Coenraad; Neefjes, Jacques

2011-01-01

MHC class II molecules (MHC-II) present peptides to T helper cells to facilitate immune responses and are strongly linked to autoimmune diseases. To unravel processes controlling MHC-II antigen presentation, we performed a genome-wide flow cytometry-based RNAi screen detecting MHC-II expression and

The Intensity of Human Body Odors and the MHC: Should We Expect a Link?

Directory of Open Access Journals (Sweden)

Claus Wedekind

2006-01-01

Full Text Available It is now well established that genes within the major histocompatibility complex (MHC somehow affect the production of body odors in several vertebrates, including humans. Here we discuss whether variation in the intensity of body odors may be influenced by the MHC. In order to examine this question, we have to control for MHC-linked odor perception on the smeller's side. Such a control is necessary because the perception of pleasantness and intensity seem to be confounded, and the causalities are still unsolved. It has previously been found that intense odors are scored as less pleasant if the signaler and the receiver are of MHC-dissimilar type, but not if they are of MHC similar type. We argue, and first data suggest, that an effect of the degree of MHC-heterozygosity and odor intensity is likely (MHC-homozygotes may normally smell more intense, while there is currently no strong argument for other possible links between the MHC and body odor intensity.

distribution and abundance of rodents in farmlands: a case study in ...

African Journals Online (AJOL)

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eruption (Pech et al., 1999). Rodent damage is rarely uniform in time; it follows crop phenology. Rice field rats cause more damage during some stages of growth of paddy than during other stages (Tristiani and Murakami,. 1998). Multimammate mice dig up planted maize seeds, but are harmless during the growth of maize.

Functional recombinant MHC class II molecules and high-throughput peptide-binding assays

DEFF Research Database (Denmark)

Justesen, Sune; Harndahl, Mikkel; Lamberth, Kasper

2009-01-01

BACKGROUND: Molecules of the class II major histocompability complex (MHC-II) specifically bind and present exogenously derived peptide epitopes to CD4+ T helper cells. The extreme polymorphism of the MHC-II hampers the complete analysis of peptide binding. It is also a significant hurdle......-II molecules and accompanying HTS peptide-binding assay were successfully developed for nine different MHC-II molecules including the DPA1*0103/DPB1*0401 (DP401) and DQA1*0501/DQB1*0201, where both alpha and beta chains are polymorphic, illustrating the advantages of producing the two chains separately....... CONCLUSION: We have successfully developed versatile MHC-II resources, which may assist in the generation of MHC class II -wide reagents, data, and tools....

Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins.

Science.gov (United States)

Sallaberry-Pincheira, Nicole; González-Acuña, Daniel; Padilla, Pamela; Dantas, Gisele P M; Luna-Jorquera, Guillermo; Frere, Esteban; Valdés-Velásquez, Armando; Vianna, Juliana A

2016-10-01

The evolutionary and adaptive potential of populations or species facing an emerging infectious disease depends on their genetic diversity in genes, such as the major histocompatibility complex (MHC). In birds, MHC class I deals predominantly with intracellular infections (e.g., viruses) and MHC class II with extracellular infections (e.g., bacteria). Therefore, patterns of MHC I and II diversity may differ between species and across populations of species depending on the relative effect of local and global environmental selective pressures, genetic drift, and gene flow. We hypothesize that high gene flow among populations of Humboldt and Magellanic penguins limits local adaptation in MHC I and MHC II, and signatures of selection differ between markers, locations, and species. We evaluated the MHC I and II diversity using 454 next-generation sequencing of 100 Humboldt and 75 Magellanic penguins from seven different breeding colonies. Higher genetic diversity was observed in MHC I than MHC II for both species, explained by more than one MHC I loci identified. Large population sizes, high gene flow, and/or similar selection pressures maintain diversity but limit local adaptation in MHC I. A pattern of isolation by distance was observed for MHC II for Humboldt penguin suggesting local adaptation, mainly on the northernmost studied locality. Furthermore, trans-species alleles were found due to a recent speciation for the genus or convergent evolution. High MHC I and MHC II gene diversity described is extremely advantageous for the long-term survival of the species.

Cutting Edge: Impaired MHC Class I Expression in Mice Deficient for Nlrc5/CITA

OpenAIRE

Biswas, Amlan; Meissner, Torsten B.; Taro Kawai,; Kobayashi, Koichi S.

2012-01-01

MHC class I and class II are crucial for the adaptive immune system. Although regulation of MHC class II expression by CIITA (class II transactivator) has long been recognized, the mechanism of MHC class I transactivation has been largely unknown until the recent discovery of NLRC5/CITA. Here we show using Nlrc5-deficient mice that NLRC5 is required for both constitutive and inducible MHC class I expression. Loss of Nlrc5 resulted in severe reduction in the expression of MHC class I and relat...

Complex assembly, crystallization and preliminary X-ray crystallographic studies of duck MHC class I molecule

International Nuclear Information System (INIS)

Zhang, Jianhua; Chen, Yong; Gao, Feng; Chen, Weihong; Qi, Jianxun; Xia, Chun

2009-01-01

Using a peptide derived from H5N1, a complex of duck MHC class I molecule (DuMHC I) with duck β 2 -microglobulin (Duβ 2 m) was assembled and crystallized. Initial structure analysis indicated that the crystals did not contain the complete DuMHC I complex but instead contained DuMHC I α3-domain and Duβ 2 m subunits. In order to understand the biological properties of the immune systems of waterfowl and to establish a system for structural studies of duck class I major histocompatibility complex (DuMHC I), a complex of DuMHC I with duck β 2 -microglobulin (Duβ 2 m) and the peptide AEIEDLIF (AF8) derived from H5N1 NP residues 251–258 was assembled. The complex was crystallized; the crystals belonged to space group C222 1 , with unit-cell parameters a = 54.7, b = 72.4, c = 102.2 Å, and diffracted to 2.3 Å resolution. Matthews coefficient calculation and initial structure determination by molecular replacement showed that the crystals did not contain the whole DuMHC I complex, but instead contained the DuMHC I α3 domain and a Duβ2m molecule (DuMHC I α3+β2m). Another complex of DuMHC I with the peptide IDWFDGKE derived from a chicken fusion protein also generated the same results. The stable structure of DuMHC I α3+β2m may reflect some unique characteristics of DuMHC I and pave the way for novel MHC structure-related studies in the future

Low genetic variation in the MHC class II DRB gene and MHC-linked microsatellites in endangered island populations of the leopard cat (Prionailurus bengalensis) in Japan.

Science.gov (United States)

Saka, Toshinori; Nishita, Yoshinori; Masuda, Ryuichi

2018-02-01

Isolated populations of the leopard cat (Prionailurus bengalensis) on Tsushima and Iriomote islands in Japan are classified as subspecies P. b. euptilurus and P. b. iriomotensis, respectively. Because both populations have decreased to roughly 100, an understanding of their genetic diversity is essential for conservation. We genotyped MHC class II DRB exon 2 and MHC-linked microsatellite loci to evaluate the diversity of MHC genes in the Tsushima and Iriomote cat populations. We detected ten and four DRB alleles in these populations, respectively. A phylogenetic analysis showed DRB alleles from both populations to be closely related to those in other felid DRB lineages, indicating trans-species polymorphism. The MHC-linked microsatellites were more polymorphic in the Tsushima than in the Iriomote population. The MHC diversity of both leopard cat populations is much lower than in the domestic cat populations on these islands, probably due to inbreeding associated with founder effects, geographical isolation, or genetic drift. Our results predict low resistance of the two endangered populations to new pathogens introduced to the islands.

Sibling rivalry: competition between MHC class II family members inhibits immunity.

Science.gov (United States)

Denzin, Lisa K; Cresswell, Peter

2013-01-01

Peptide loading of major histocompatibility complex (MHC) class II molecules in the endosomes and lysosomes of antigen-presenting cells is catalyzed by human leukocyte antigen-DM (HLA-DM) and modulated by HLA-DO. In a structural study in this issue, Guce et al. show that HLA-DO is an MHC class II mimic and functions as a competitive and essentially irreversible inhibitor of HLA-DM activity, thereby inhibiting MHC class II antigen presentation.

Leukemia prevention and long-term survival of AKR mice transplanted with MHC-matched or MHC-mismatched bone marrow

International Nuclear Information System (INIS)

Longley, R.E.; Good, R.A.

1986-01-01

The current studies were designed to evaluate the effectiveness of marrow transplantation within and outside the major histocompatibility complex (MHC) on the long-term survival and occurrence of spontaneous leukemia in AKR mice. AKR mice, which were lethally irradiated and received MHC-matched marrow from CBA/J mice (CBA----AKR), never developed leukemia and were alive and remained healthy for up to 280 days post-transplant. These long-term surviving chimeras possessed substantial immune vigor when both cell-mediated and humoral responses were tested. Lethally irradiated AKR mice, which had received MHC-mismatched marrow (anti-Thy-1.2 treated or nontreated) from C57BL/6J mice (B6----AKR), never developed leukemia and survived up to 170 days post-transplant. However, both groups of these chimeras began dying 180 to 270 days post-transplant due to a disease process which could not be readily identified. Histological analysis of B6----AKR chimeras revealed severe lymphoid cell depletion in thymus and spleen; however, none of these chimeras exhibited classical features of acute graft versus host disease. Concanavalin A mitogenesis, primary antibody responses to sheep red blood cells and the production of interleukin 2 (IL-2) were suppressed in B6----AKR chimeras. IL-2 treatment of B6----AKR chimeras was shown to partially correct these deficiencies without stimulating mixed lymphocyte responsiveness to donor or host lymphocytes. These studies indicate that the use of MHC-mismatched marrow for the prevention of spontaneous AKR leukemia may rely on augmentative IL-2 therapy for complete immune reconstitution of leukemia-free chimeras

Social pairing of Seychelles warblers under reduced constraints: MHC, neutral heterozygosity, and age.

Science.gov (United States)

Wright, David J; Brouwer, Lyanne; Mannarelli, Maria-Elena; Burke, Terry; Komdeur, Jan; Richardson, David S

2016-01-01

The prevalence and significance of precopulatory mate choice remains keenly debated. The major histocompatibility complex (MHC) plays a key role in vertebrate adaptive immunity, and variation at the MHC influences individual survival. Although MHC-dependent mate choice has been documented in certain species, many other studies find no such pattern. This may be, at least in part, because in natural systems constraints may reduce the choices available to individuals and prevent full expression of underlying preferences. We used translocations to previously unoccupied islands to experimentally reduce constraints on female social mate choice in the Seychelles warbler ( Acrocephalus sechellensis ), a species in which patterns of MHC-dependent extrapair paternity (EPP), but not social mate choice, have been observed. We find no evidence of MHC-dependent social mate choice in the new populations. Instead, we find that older males and males with more microsatellite heterozygosity are more likely to have successfully paired. Our data cannot resolve whether these patterns in pairing were due to male-male competition or female choice. However, our research does suggest that female Seychelles warblers do not choose social mates using MHC class I to increase fitness. It may also indicate that the MHC-dependent EPP observed in the source population is probably due to mechanisms other than female precopulatory mate choice based on MHC cues.

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...

Statistical deconvolution of enthalpic energetic contributions to MHC-peptide binding affinity

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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.

Characterization of MHC class I in a long distance migratory wader, the Icelandic black-tailed godwit.

Science.gov (United States)

Pardal, Sara; Drews, Anna; Alves, José A; Ramos, Jaime A; Westerdahl, Helena

2017-07-01

The major histocompatibility complex (MHC) encodes proteins that are central for antigen presentation and pathogen elimination. MHC class I (MHC-I) genes have attracted a great deal of interest among researchers in ecology and evolution and have been partly characterized in a wide range of bird species. So far, the main focus has been on species within the bird orders Galliformes and Passeriformes, while Charadriiformes remain vastly underrepresented with only two species studied to date. These two Charadriiformes species exhibit striking differences in MHC-I characteristics and MHC-I diversity. We therefore set out to study a third species within Charadriiformes, the Icelandic subspecies of black-tailed godwits (Limosa limosa islandica). This subspecies is normally confined to parasite-poor environments, and we hence expected low MHC diversity. MHC-I was partially characterized first using Sanger sequencing and then using high-throughput sequencing (MiSeq) in 84 individuals. We verified 47 nucleotide alleles in open reading frame with classical MHC-I characteristics, and each individual godwit had two to seven putatively classical MHC alleles. However, in contrast to previous MHC-I data within Charadriiformes, we did not find any evidence of alleles with low sequence diversity, believed to represent non-classical MHC genes. The diversity and divergence of the godwits MHC-I genes to a large extent fell between the previous estimates within Charadriiformes. However, the MHC genes of the migratory godwits had few sites subject to positive selection, and one possible explanation could be a low exposure to pathogens.

Ubiquitination regulates MHC class II-peptide complex retention and degradation in dendritic cells

OpenAIRE

Walseng, Even; Furuta, Kazuyuki; Bosch, Berta; Weih, Karis A.; Matsuki, Yohei; Bakke, Oddmund; Ishido, Satoshi; Roche, Paul A.

2010-01-01

The expression and turnover of MHC class II-peptide complexes (pMHC-II) on the surface of dendritic cells (DCs) is essential for their ability to activate CD4 T cells efficiently. The half-life of surface pMHC-II is significantly greater in activated (mature) DCs than in resting (immature) DCs, but the molecular mechanism leading to this difference remains unknown. We now show that ubiquitination of pMHC-II by the E3 ubiquitin ligase membrane-associated RING-CH 1 (March-I) regulates surface e...

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

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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.

Regulation of an antisense RNA with the transition of neonatal to IIb myosin heavy chain during postnatal development and hypothyroidism in rat skeletal muscle.

Science.gov (United States)

Pandorf, Clay E; Jiang, Weihua; Qin, Anqi X; Bodell, Paul W; Baldwin, Kenneth M; Haddad, Fadia

2012-04-01

Postnatal development of fast skeletal muscle is characterized by a transition in expression of myosin heavy chain (MHC) isoforms, from primarily neonatal MHC at birth to primarily IIb MHC in adults, in a tightly coordinated manner. These isoforms are encoded by distinct genes, which are separated by ∼17 kb on rat chromosome 10. The neonatal-to-IIb MHC transition is inhibited by a hypothyroid state. We examined RNA products [mRNA, pre-mRNA, and natural antisense transcript (NAT)] of developmental and adult-expressed MHC genes (embryonic, neonatal, I, IIa, IIx, and IIb) at 2, 10, 20, and 40 days after birth in normal and thyroid-deficient rat neonates treated with propylthiouracil. We found that a long noncoding antisense-oriented RNA transcript, termed bII NAT, is transcribed from a site within the IIb-Neo intergenic region and across most of the IIb MHC gene. NATs have previously been shown to mediate transcriptional repression of sense-oriented counterparts. The bII NAT is transcriptionally regulated during postnatal development and in response to hypothyroidism. Evidence for a regulatory mechanism is suggested by an inverse relationship between IIb MHC and bII NAT in normal and hypothyroid-treated muscle. Neonatal MHC transcription is coordinately expressed with bII NAT. A comparative phylogenetic analysis also suggests that bII NAT-mediated regulation has been a conserved trait of placental mammals for most of the eutherian evolutionary history. The evidence in support of the regulatory model implicates long noncoding antisense RNA as a mechanism to coordinate the transition between neonatal and IIb MHC during postnatal development.

Dimeric MHC-peptides inserted into an immunoglobulin scaffold as new immunotherapeutic agents

Science.gov (United States)

Goldberg, Burt; Bona, Constantin

2011-01-01

Abstract The interactions of the T cell receptor (TCR) with cognate MHC-peptide and co-stimulatory molecules expressed at surface of antigen presenting cells (APC) leads to activation or tolerance of T cells. The development of molecular biological tools allowed for the preparation of soluble MHC-peptide molecules as surrogate for the APC. A decade ago a monomeric class II MHC molecule in which the peptide was covalently linked to β-chain of class II molecule was generated. This type of molecule had a low-binding affinity and did not cause the multimerization of TCR. The requirement of multimerization of TCR led to development of a new class of reagents, chimeric peptides covalently linked to MHC that was dimerized via Fc fragment of an immunoglobulin and linked to 3′ end of the β-chain of MHC class II molecule. These soluble dimerized MHC-peptide chimeric molecules display high affinity for the TCR and caused multimerization of TCR without processing by an APC. Because dimeric molecules are devoid of co-stimulatory molecules interacting with CD28, a second signal, they induce anergy rather the activation of T cells. In this review, we compare the human and murine dimerized MHC class II-peptides and their effect on CD4+ T cells, particularly the generation of T regulatory cells, which make these chimeric molecules an appealing approach for the treatment of autoimmune diseases. PMID:21435177

Establishment of a quantitative ELISA capable of determining peptide - MHC class I interaction

DEFF Research Database (Denmark)

Sylvester-Hvid, C; Kristensen, N; Blicher, T

2002-01-01

dependent manner. Here, we exploit the availability of these molecules to generate a quantitative ELISA-based assay capable of measuring the affinity of the interaction between peptide and MHC-I. This assay is simple and sensitive, and one can easily envisage that the necessary reagents, standards......Many different assays for measuring peptide-MHC interactions have been suggested over the years. Yet, there is no generally accepted standard method available. We have recently generated preoxidized recombinant MHC class I molecules (MHC-I) which can be purified to homogeneity under denaturing...

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.

Structure of a pheromone receptor-associated MHC molecule with an open and empty groove.

Directory of Open Access Journals (Sweden)

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.

Schwann cells promote post-traumatic nerve inflammation and neuropathic pain through MHC class II.

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Hartlehnert, Maike; Derksen, Angelika; Hagenacker, Tim; Kindermann, David; Schäfers, Maria; Pawlak, Mathias; Kieseier, Bernd C; Meyer Zu Horste, Gerd

2017-10-02

The activation of T helper cells requires antigens to be exposed on the surface of antigen presenting cells (APCs) via MHC class II (MHC-II) molecules. Expression of MHC-II is generally limited to professional APCs, but other cell types can express MHC-II under inflammatory conditions. However, the importance of these conditional APCs is unknown. We and others have previously shown that Schwann cells are potentially conditional APCs, but the functional relevance of MHC-II expression by Schwann cells has not been studied in vivo. Here, we conditionally deleted the MHC-II β-chain from myelinating Schwann cells in mice and investigated how this influenced post-traumatic intraneural inflammation and neuropathic pain using the chronic constriction injury (CCI) model. We demonstrate that deletion of MHC-II in myelinating Schwann cells reduces thermal hyperalgesia and, to a lesser extent, also diminishes mechanical allodynia in CCI in female mice. This was accompanied by a reduction of intraneural CD4+ T cells and greater preservation of preferentially large-caliber axons. Activation of T helper cells by MHC-II on Schwann cells thus promotes post-traumatic axonal loss and neuropathic pain. Hence, we provide experimental evidence that Schwann cells gain antigen-presenting function in vivo and modulate local immune responses and diseases in the peripheral nerves.

Peptide and Peptide-Dependent Motions in MHC Proteins: Immunological Implications and Biophysical Underpinnings

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Cory M. Ayres

2017-08-01

Full Text Available Structural biology of peptides presented by class I and class II MHC proteins has transformed immunology, impacting our understanding of fundamental immune mechanisms and allowing researchers to rationalize immunogenicity and design novel vaccines. However, proteins are not static structures as often inferred from crystallographic structures. Their components move and breathe individually and collectively over a range of timescales. Peptides bound within MHC peptide-binding grooves are no exception and their motions have been shown to impact recognition by T cell and other receptors in ways that influence function. Furthermore, peptides tune the motions of MHC proteins themselves, which impacts recognition of peptide/MHC complexes by other proteins. Here, we review the motional properties of peptides in MHC binding grooves and discuss how peptide properties can influence MHC motions. We briefly review theoretical concepts about protein motion and highlight key data that illustrate immunological consequences. We focus primarily on class I systems due to greater availability of data, but segue into class II systems as the concepts and consequences overlap. We suggest that characterization of the dynamic “energy landscapes” of peptide/MHC complexes and the resulting functional consequences is one of the next frontiers in structural immunology.

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

OpenAIRE

Garman, Lori; Dumas, Eric K.; Kurella, Sridevi; Hunt, Jonathan J.; Crowe, Sherry R.; Nguyen, Melissa L.; Cox, Philip M.; James, Judith A.; Farris, A. Darise

2012-01-01

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 I...

Modulation of the major histocompatibility complex by neural stem cell-derived neurotrophic factors used for regenerative therapy in a rat model of stroke

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Sun Chongran

2010-08-01

Full Text Available Abstract Background The relationship between functional improvements in ischemic rats given a neural stem cell (NSC transplant and the modulation of the class I major histocompatibility complex (MHC mediated by NSC-derived neurotrophins was investigated. Methods The levels of gene expression of nerve growth factor (NGF, brain-derived neurotropic factor (BDNF and neurotrophin-3 (NT-3 were assayed from cultures of cortical NSC from Sprague-Dawley rat E16 embryos. The levels of translated NGF in spent culture media from NSC cultures and the cerebral spinal fluid (CSF of rats with and without NGF injection or NSC transplant were also measured. Results We found a significant increase of NGF, BDNF and NT-3 transcripts and NGF proteins in both the NSC cultures and the CSF of the rats. The immunochemical staining for MHC in brain sections and the enzyme-linked immunosorbent assay of CSF were carried out in sham-operated rats and rats with surgically induced focal cerebral ischemia. These groups were further divided into animals that did and did not receive NGF administration or NSC transplant into the cisterna magna. Our results show an up-regulation of class I MHC in the ischemic rats with NGF and NSC administration. The extent of caspase-III immunoreactivity was comparable among three arms in the ischemic rats. Conclusion Readouts of somatosensory evoked potential and the trap channel test illustrated improvements in the neurological function of ischemic rats treated with NGF administration and NSC transplant.

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...

H pylori receptor MHC class II contributes to the dynamic gastric epithelial apoptotic response

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Bland, David A; Suarez, Giovanni; Beswick, Ellen J; Sierra, Johanna C; Reyes, Victor E

2006-01-01

AIM: To investigate the role of MHC class II in the modulation of gastric epithelial cell apoptosis induced by H pylori infection. METHODS: After stimulating a human gastric epithelial cell line with bacteria or agonist antibodies specific for MHC class II and CD95, the quantitation of apoptotic and anti-apoptotic events, including caspase activation, BCL-2 activation, and FADD recruitment, was performed with a fluorometric assay, a cytometric bead array, and confocal microscopy, respectively. RESULTS: Pretreatment of N87 cells with the anti-MHC class II IgM antibody RFD1 resulted in a reduction in global caspase activation at 24 h of H pylori infection. When caspase 3 activation was specifically measured, crosslinking of MHC class II resulted in a marked reduced caspase activation, while simple ligation of MHC class II did not. Crosslinking of MHC class II also resulted in an increased activation of the anti-apoptosis molecule BCL-2 compared to simple ligation. Confocal microscope analysis demonstrated that the pretreatment of gastric epithelial cells with a crosslinking anti-MHC class II IgM blocked the recruitment of FADD to the cell surface. CONCLUSION: The results presented here demonstrate that the ability of MHC class II to modulate gastric epithelial apoptosis is at least partially dependent on its crosslinking. Furthermore, while previous research has demonstrated that MHC class II signaling can be pro-apoptotic during extended ligation, we have shown that the crosslinking of this molecule has anti-apoptotic effects during the earlier time points of H pylori infection. This effect is possibly mediated by the ability of MHC class II to modulate the activation of the pro-apoptotic receptor Fas by blocking the recruitment of the accessory molecule FADD, and this delay in apoptosis induction could allow for prolonged cytokine secretion by H pylori-infected gastric epithelial cells. PMID:16981259

Gene transfer preferentially selects MHC class I positive tumour cells and enhances tumour immunogenicity.

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Hacker, Ulrich T; Schildhauer, Ines; Barroso, Margarita Céspedes; Kofler, David M; Gerner, Franz M; Mysliwietz, Josef; Buening, Hildegard; Hallek, Michael; King, Susan B S

2006-05-01

The modulated expression of MHC class I on tumour tissue is well documented. Although the effect of MHC class I expression on the tumorigenicity and immunogenicity of MHC class I negative tumour cell lines has been rigorously studied, less is known about the validity of gene transfer and selection in cell lines with a mixed MHC class I phenotype. To address this issue we identified a C26 cell subline that consists of distinct populations of MHC class I (H-2D/K) positive and negative cells. Transient transfection experiments using liposome-based transfer showed a lower transgene expression in MHC class I negative cells. In addition, MHC class I negative cells were more sensitive to antibiotic selection. This led to the generation of fully MHC class I positive cell lines. In contrast to C26 cells, all transfectants were rejected in vivo and induced protection against the parental tumour cells in rechallenge experiments. Tumour cell specificity of the immune response was demonstrated in in vitro cytokine secretion and cytotoxicity assays. Transfectants expressing CD40 ligand and hygromycin phosphotransferase were not more immunogenic than cells expressing hygromycin resistance alone. We suggest that the MHC class I positive phenotype of the C26 transfectants had a bearing on their immunogenicity, because selected MHC class I positive cells were more immunogenic than parental C26 cells and could induce specific anti-tumour immune responses. These data demonstrate that the generation of tumour cell transfectants can lead to the selection of subpopulations that show an altered phenotype compared to the parental cell line and display altered immunogenicity independent of selection marker genes or other immune modulatory genes. Our results show the importance of monitoring gene transfer in the whole tumour cell population, especially for the evaluation of in vivo therapies targeted to heterogeneous tumour cell populations.

Low MHC variation in the endangered Galápagos penguin (Spheniscus mendiculus).

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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.

Ligation of MHC class I molecules on peripheral blood T lymphocytes induces new phenotypes and functions

DEFF Research Database (Denmark)

Bregenholt, S; Röpke, M; Skov, S

1996-01-01

of T cell-mediated cytotoxicity. Immediately following MHC-I ligation, the T cells responded with increased protein tyrosine phosphorylation, with new bands appearing in the SDS-PAGE. Exposure of T cells to immobilized anti-MHC-I Ab for 24 h induced an increased surface expression of the TCR/CD3 and CD......28 molecules. MHC-I-induced proliferation of purified T cells was dependent on cellular interactions with non-T cells. Under certain conditions, in which MHC-I was ligated by picogram concentrations of immobilized anti-MHC-I Ab, anti-TCR/CD3 Ab-induced proliferation of T cells was strongly inhibited....... These data clearly demonstrate that ligation of the MHC-I complex on T cells may induce both positive and negative signals. Since the physiologic ligands for MHC-I molecules are TCR and the CD8 molecules, our data may suggest that MHC-I molecules are instrumental in cellular interactions between T cells....

NLRC5/MHC class I transactivator is a target for immune evasion in cancer.

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Yoshihama, Sayuri; Roszik, Jason; Downs, Isaac; Meissner, Torsten B; Vijayan, Saptha; Chapuy, Bjoern; Sidiq, Tabasum; Shipp, Margaret A; Lizee, Gregory A; Kobayashi, Koichi S

2016-05-24

Cancer cells develop under immune surveillance, thus necessitating immune escape for successful growth. Loss of MHC class I expression provides a key immune evasion strategy in many cancers, although the molecular mechanisms remain elusive. MHC class I transactivator (CITA), known as "NLRC5" [NOD-like receptor (NLR) family, caspase recruitment (CARD) domain containing 5], has recently been identified as a critical transcriptional coactivator of MHC class I gene expression. Here we show that the MHC class I transactivation pathway mediated by CITA/NLRC5 constitutes a target for cancer immune evasion. In all the 21 tumor types we examined, NLRC5 expression was highly correlated with the expression of MHC class I, with cytotoxic T-cell markers, and with genes in the MHC class I antigen-presentation pathway, including LMP2/LMP7, TAP1, and β2-microglobulin. Epigenetic and genetic alterations in cancers, including promoter methylation, copy number loss, and somatic mutations, were most prevalent in NLRC5 among all MHC class I-related genes and were associated with the impaired expression of components of the MHC class I pathway. Strikingly, NLRC5 expression was significantly associated with the activation of CD8(+) cytotoxic T cells and patient survival in multiple cancer types. Thus, NLRC5 constitutes a novel prognostic biomarker and potential therapeutic target of cancers.

Neurons are MHC class I-dependent targets for CD8 T cells upon neurotropic viral infection.

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Grégoire Chevalier

2011-11-01

Full Text Available Following infection of the central nervous system (CNS, the immune system is faced with the challenge of eliminating the pathogen without causing significant damage to neurons, which have limited capacities of renewal. In particular, it was thought that neurons were protected from direct attack by cytotoxic T lymphocytes (CTL because they do not express major histocompatibility class I (MHC I molecules, at least at steady state. To date, most of our current knowledge on the specifics of neuron-CTL interaction is based on studies artificially inducing MHC I expression on neurons, loading them with exogenous peptide and applying CTL clones or lines often differentiated in culture. Thus, much remains to be uncovered regarding the modalities of the interaction between infected neurons and antiviral CD8 T cells in the course of a natural disease. Here, we used the model of neuroinflammation caused by neurotropic Borna disease virus (BDV, in which virus-specific CTL have been demonstrated as the main immune effectors triggering disease. We tested the pathogenic properties of brain-isolated CD8 T cells against pure neuronal cultures infected with BDV. We observed that BDV infection of cortical neurons triggered a significant up regulation of MHC I molecules, rendering them susceptible to recognition by antiviral CTL, freshly isolated from the brains of acutely infected rats. Using real-time imaging, we analyzed the spatio-temporal relationships between neurons and CTL. Brain-isolated CTL exhibited a reduced mobility and established stable contacts with BDV-infected neurons, in an antigen- and MHC-dependent manner. This interaction induced rapid morphological changes of the neurons, without immediate killing or impairment of electrical activity. Early signs of neuronal apoptosis were detected only hours after this initial contact. Thus, our results show that infected neurons can be recognized efficiently by brain-isolated antiviral CD8 T cells and

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

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 b...

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...... 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...

Ginger extract mitigates ethanol-induced changes of alpha and beta - myosin heavy chain isoforms gene expression and oxidative stress in the heart of male wistar rats.

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Shirpoor, Alireza; Zerehpoosh, Mitra; Ansari, Mohammad Hasan Khadem; Kheradmand, Fatemeh; Rasmi, Yousef

2017-09-01

The association between ethanol consumption and heart abnormalities, such as chamber dilation, myocyte damage, ventricular hypertrophy, and hypertension is well known. However, underlying molecular mediators involved in ethanol-induced heart abnormalities remain elusive. The aim of this study was to investigate the effect of chronic ethanol exposure on alpha and beta - myosin heavy chain (MHC) isoforms gene expression transition and oxidative stress in rats' heart. It was also planned to find out whether ginger extract mitigated the abnormalities induced by ethanol in rats' heart. Male wistar rats were divided into three groups of eight animals as follows: Control, ethanol, and ginger extract treated ethanolic (GETE) groups. After six weeks of treatment, the results revealed a significant increase in the β-MHC gene expression, 8- OHdG amount, and NADPH oxidase level. Furthermore, a significant decrease in the ratio of α-MHC/β-MHC gene expression to the amount of paraoxonase enzyme in the ethanol group compared to the control group was found. The consumption of Ginger extract along with ethanol ameliorated the changes in MHC isoforms gene expression and reduced the elevated amount of 8-OHdG and NADPH oxidase. Moreover, compared to the consumption of ethanol alone, it increased the paraoxonase level significantly. These findings indicate that ethanol-induced heart abnormalities may in part be associated with MHC isoforms changes mediated by oxidative stress, and that these effects can be alleviated by using ginger extract as an antioxidant molecule. Copyright © 2017 Elsevier B.V. All rights reserved.

Exosomal cancer immunotherapy is independent of MHC molecules on exosomes.

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Hiltbrunner, Stefanie; Larssen, Pia; Eldh, Maria; Martinez-Bravo, Maria-Jose; Wagner, Arnika K; Karlsson, Mikael C I; Gabrielsson, Susanne

2016-06-21

Peptide-loaded exosomes are promising cancer treatment vehicles; however, moderate T cell responses in human clinical trials indicate a need to further understand exosome-induced immunity. We previously demonstrated that antigen-loaded exosomes carry whole protein antigens and require B cells for inducing antigen-specific T cells. Therefore, we investigated the relative importance of exosomal major histocompatibility complex (MHC) class I for the induction of antigen-specific T cell responses and tumour protection. We show that ovalbumin-loaded dendritic cell-derived exosomes from MHCI-/- mice induce antigen-specific T cells at the same magnitude as wild type exosomes. Furthermore, exosomes lacking MHC class I, as well as exosomes with both MHC class I and II mismatch, induced tumour infiltrating T cells and increased overall survival to the same extent as syngeneic exosomes in B16 melanoma. In conclusion, T cell responses are independent of exosomal MHC/peptide complexes if whole antigen is present. This establishes the prospective of using impersonalised exosomes, and will greatly increase the feasibility of designing exosome-based vaccines or therapeutic approaches in humans.

Identification of the cognate peptide-MHC target of T cell receptors using molecular modeling and force field scoring

DEFF Research Database (Denmark)

Lanzarotti, Esteban; Marcatili, Paolo; Nielsen, Morten

2018-01-01

Interactions of T cell receptors (TCR) to peptides in complex with MHC (p:MHC) are key features that mediate cellular immune responses. While MHC binding is required for a peptide to be presented to T cells, not all MHC binders are immunogenic. The interaction of a TCR to the p:MHC complex holds...... terms. Building a benchmark of TCR:p:MHC complexes where epitopes and non-epitopes are modelled using state-of-the-art molecular modelling tools, scoring p:MHC to a given TCR using force-fields, optimized in a cross-validation setup to evaluate TCR inter atomic interactions involved with each p:MHC, we...... and model the TCR:p:MHC complex structure. In summary, we conclude that it is possible to identify the TCR cognate target among different candidate peptides by using a force-field based model, and believe this works could lay the foundation for future work within prediction of TCR:p:MHC interactions....

Predicted MHC peptide binding promiscuity explains MHC class I 'hotspots' of antigen presentation defined by mass spectrometry eluted ligand data.

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Jappe, Emma Christine; Kringelum, Jens; Trolle, Thomas; Nielsen, Morten

2018-02-15

Peptides that bind to and are presented by MHC class I and class II molecules collectively make up the immunopeptidome. In the context of vaccine development, an understanding of the immunopeptidome is essential, and much effort has been dedicated to its accurate and cost-effective identification. Current state-of-the-art methods mainly comprise in silico tools for predicting MHC binding, which is strongly correlated with peptide immunogenicity. However, only a small proportion of the peptides that bind to MHC molecules are, in fact, immunogenic, and substantial work has been dedicated to uncovering additional determinants of peptide immunogenicity. In this context, and in light of recent advancements in mass spectrometry (MS), the existence of immunological hotspots has been given new life, inciting the hypothesis that hotspots are associated with MHC class I peptide immunogenicity. We here introduce a precise terminology for defining these hotspots and carry out a systematic analysis of MS and in silico predicted hotspots. We find that hotspots defined from MS data are largely captured by peptide binding predictions, enabling their replication in silico. This leads us to conclude that hotspots, to a great degree, are simply a result of promiscuous HLA binding, which disproves the hypothesis that the identification of hotspots provides novel information in the context of immunogenic peptide prediction. Furthermore, our analyses demonstrate that the signal of ligand processing, although present in the MS data, has very low predictive power to discriminate between MS and in silico defined hotspots. © 2018 John Wiley & Sons Ltd.

Pulpal responses to cavity preparation in aged rat molars.

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Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato

2006-10-01

The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, few data are available concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense in aged pulp by investigating the responses of odontoblasts and cells positive for class II major histocompatibility complex (MHC) to cavity preparation in aged rat molars (300-360 days) and by comparing the results with those in young adult rats (100 days). In untreated control teeth, immunoreactivity for intense heat-shock protein (HSP)-25 and nestin was found in odontoblasts, whereas class-II-MHC-positive cells were densely distributed in the periphery of the pulp. Cavity preparation caused two types of pulpal reactions based on the different extent of damage in the aged rats. In the case of severe damage, destruction of the odontoblast layer was conspicuous at the affected site. By 12 h after cavity preparation, numerous class-II-MHC-positive cells appeared along the pulp-dentin border but subsequently disappeared together with HSP-25-immunopositive cells, and finally newly differentiated odontoblast-like cells took the place of the degenerated odontoblasts and acquired immunoreactivity for HSP-25 and nestin by postoperative day 3. In the case of mild damage, no remarkable changes occurred in odontoblasts after operation, and some survived through the experimental stages. These findings indicate that aged pulp tissue still possesses a defense capacity, and that a variety of reactions can occur depending on the difference in the status of dentinal tubules and/or odontoblast processes in individuals.

Circumvention of MHC class II restriction by genetic immunization.

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Schuler, K; Lu, C; Chang, H D; Croft, M; Zanetti, M; Gerloni, M

2001-11-12

The fate of T cell responses to peptide-based vaccination is subject to constraints by the major histocompatibility complex (MHC), MHC restriction. Using as a model system of T and B cell epitopes from the circumsporozoite protein of Plasmodium falciparum malaria parasite, we show that vaccination by somatic transgene immunization readily primes Balb/c mice (H-2(d)) a strain previously reported to be non-responder to immunization with a synthetic peptide vaccine encompassing these epitopes. Following genetic vaccination Balb/c mice developed a primary T cell response comparable to that of the responder strain C57Bl/6 (H-2(b)). Following booster immunization on day 45 Balb/c mice responded with a typical T cell memory response. Priming induced the formation of specific antibodies, which rose sharply after booster immunization. These findings suggests that genetic immunization can circumvent MHC class II restriction.

The importance of immune gene variability (MHC in evolutionary ecology and conservation

Directory of Open Access Journals (Sweden)

Sommer Simone

2005-10-01

Full Text Available Abstract Genetic studies have typically inferred the effects of human impact by documenting patterns of genetic differentiation and levels of genetic diversity among potentially isolated populations using selective neutral markers such as mitochondrial control region sequences, microsatellites or single nucleotide polymorphism (SNPs. However, evolutionary relevant and adaptive processes within and between populations can only be reflected by coding genes. In vertebrates, growing evidence suggests that genetic diversity is particularly important at the level of the major histocompatibility complex (MHC. MHC variants influence many important biological traits, including immune recognition, susceptibility to infectious and autoimmune diseases, individual odours, mating preferences, kin recognition, cooperation and pregnancy outcome. These diverse functions and characteristics place genes of the MHC among the best candidates for studies of mechanisms and significance of molecular adaptation in vertebrates. MHC variability is believed to be maintained by pathogen-driven selection, mediated either through heterozygote advantage or frequency-dependent selection. Up to now, most of our knowledge has derived from studies in humans or from model organisms under experimental, laboratory conditions. Empirical support for selective mechanisms in free-ranging animal populations in their natural environment is rare. In this review, I first introduce general information about the structure and function of MHC genes, as well as current hypotheses and concepts concerning the role of selection in the maintenance of MHC polymorphism. The evolutionary forces acting on the genetic diversity in coding and non-coding markers are compared. Then, I summarise empirical support for the functional importance of MHC variability in parasite resistance with emphasis on the evidence derived from free-ranging animal populations investigated in their natural habitat. Finally, I

Characterization of MHC class I and II genes in a subantarctic seabird, the blue petrel, Halobaena caerulea (Procellariiformes).

Science.gov (United States)

Strandh, Maria; Lannefors, Mimi; Bonadonna, Francesco; Westerdahl, Helena

2011-10-01

The great polymorphism observed in the major histocompatibility complex (MHC) genes is thought to be maintained by pathogen-mediated selection possibly combined with MHC-disassortative mating, guided by MHC-determined olfactory cues. Here, we partly characterize the MHC class I and II B of the blue petrel, Halobaena caerulea (Procellariiformes), a bird with significant olfactory abilities that lives under presumably low pathogen burdens in Subantarctica. Blue petrels are long-lived, monogamous birds which suggest the necessity of an accurate mate choice process. The species is ancestral to songbirds (Passeriformes; many MHC loci), although not to gamefowls (Galliformes; few MHC loci). Considering the phylogenetic relationships and the low subantarctic pathogen burden, we expected few rather than many MHC loci in the blue petrel. However, when we analysed partial MHC class I and class II B cDNA and gDNA sequences we found evidence for as many as at least eight MHC class I loci and at least two class II B loci. These class I and II B sequences showed classical MHC characteristics, e.g. high nucleotide diversity, especially in putative peptide-binding regions where signatures of positive selection was detected. Trans-species polymorphism was found between MHC class II B sequences of the blue petrel and those of thin-billed prion, Pachyptila belcheri, two species that diverged ∼25 MYA. The observed MHC allele richness in the blue petrel may well serve as a basis for mate choice, especially since olfactory discrimination of MHC types may be possible in this species.

Gapped sequence alignment using artificial neural networks: application to the MHC class I system

DEFF Research Database (Denmark)

Andreatta, Massimo; Nielsen, Morten

2016-01-01

. On this relatively simple system, we developed a sequence alignment method based on artificial neural networks that allows insertions and deletions in the alignment. Results: We show that prediction methods based on alignments that include insertions and deletions have significantly higher performance than methods...... trained on peptides of single lengths. Also, we illustrate how the location of deletions can aid the interpretation of the modes of binding of the peptide-MHC, as in the case of long peptides bulging out of the MHC groove or protruding at either terminus. Finally, we demonstrate that the method can learn...... the length profile of different MHC molecules, and quantified the reduction of the experimental effort required to identify potential epitopes using our prediction algorithm. Availability and implementation: The NetMHC-4.0 method for the prediction of peptide-MHC class I binding affinity using gapped...

Crystal structure of a TAPBPR–MHC I complex reveals the mechanism of peptide editing in antigen presentation

Energy Technology Data Exchange (ETDEWEB)

Jiang, Jiansheng; Natarajan, Kannan; Boyd, Lisa F.; Morozov, Giora I.; Mage, Michael G.; Margulies, David H. (NIH); (Hebrew)

2017-10-12

Central to CD8+ T cell–mediated immunity is the recognition of peptide–major histocompatibility complex class I (p–MHC I) proteins displayed by antigen-presenting cells. Chaperone-mediated loading of high-affinity peptides onto MHC I is a key step in the MHC I antigen presentation pathway. However, the structure of MHC I with a chaperone that facilitates peptide loading has not been determined. We report the crystal structure of MHC I in complex with the peptide editor TAPBPR (TAP-binding protein–related), a tapasin homolog. TAPBPR remodels the peptide-binding groove of MHC I, resulting in the release of low-affinity peptide. Changes include groove relaxation, modifications of key binding pockets, and domain adjustments. This structure captures a peptide-receptive state of MHC I and provides insights into the mechanism of peptide editing by TAPBPR and, by analogy, tapasin.

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...

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

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

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

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

2013-07-01

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 investigated using both PCR-based methods and unamplified genomic DNA with restriction fragment length polymorphism (RFLP) and southern blots. A total of 13 different exon 2 sequences were obtained independently from DNA and/or RNA, thus confirming gene transcription and likely functionality of the genes. Nine out of 13 alleles were found in more than one country, and two alleles appeared in all countries. Positive selection was detected in the region coding for the peptide binding region (PBR). A maximum of three alleles per individual was detected by sequencing and the RFLP pattern consisted of 4-7 fragments, indicating a minimum number of 2-4 loci per individual. A phylogenetic analysis, demonstrated that the blue tit sequences are divergent compared to sequences from other passerines resembling a different MHC lineage than those possessed by most passerines studied to date.

Disentangling the roles of natural selection and genetic drift in shaping variation at MHC immunity genes.

Science.gov (United States)

Sutton, Jolene T; Nakagawa, Shinichi; Robertson, Bruce C; Jamieson, Ian G

2011-11-01

The major histocompatibility complex (MHC) forms an integral component of the vertebrate immune response and, due to strong selection pressures, is one of the most polymorphic regions of the entire genome. Despite over 15 years of research, empirical studies offer highly contradictory explanations of the relative roles of different evolutionary forces, selection and genetic drift, acting on MHC genes during population bottlenecks. Here, we take a meta-analytical approach to quantify the results of studies into the effects of bottlenecks on MHC polymorphism. We show that the consequences of selection acting on MHC loci prior to a bottleneck event, combined with drift during the bottleneck, will result in overall loss of MHC polymorphism that is ∼15% greater than loss of neutral genetic diversity. These results are counter to general expectations that selection should maintain MHC polymorphism, but do agree with the results of recent simulation models and at least two empirical studies. Notably, our results suggest that negative frequency-dependent selection could be more important than overdominance for maintaining high MHC polymorphism in pre-bottlenecked populations. © 2011 Blackwell Publishing Ltd.

Pulpal responses to cavity preparation in aged rat molars

OpenAIRE

Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato; 大島, 勇人

2006-01-01

The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, there are few available data concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense of aged pulp by investigating the responses of odontoblasts and class II major histocompatibility complex (MHC)-positive cells to cavity preparation in aged rat molars (300-360 d) and comparing the results with those in young adult rats (100...

Contrasting patterns of selection between MHC I and II across populations of Humboldt and Magellanic penguins

OpenAIRE

Sallaberry?Pincheira, Nicole; Gonz?lez?Acu?a, Daniel; Padilla, Pamela; Dantas, Gisele P. M.; Luna?Jorquera, Guillermo; Frere, Esteban; Vald?s?Vel?squez, Armando; Vianna, Juliana A.

2016-01-01

Abstract The evolutionary and adaptive potential of populations or species facing an emerging infectious disease depends on their genetic diversity in genes, such as the major histocompatibility complex (MHC). In birds, MHC class I deals predominantly with intracellular infections (e.g., viruses) and MHC class II with extracellular infections (e.g., bacteria). Therefore, patterns of MHC I and II diversity may differ between species and across populations of species depending on the relative e...

Interferon beta 1, an intermediate in the tumor necrosis factor alpha- induced increased MHC class I expression and an autocrine regulator of the constitutive MHC class I expression

OpenAIRE

1987-01-01

In conclusion, our observations indicate that the constitutive MHC class I expression is regulated by autocrine production of IFN-beta 1. TNF-alpha acts as an enhancer of the autocrine production of IFN-beta 1, and consequently as an enhancer of the MHC class I expression and viral protection.

Evolution of MHC class I in the Order Crocodylia

DEFF Research Database (Denmark)

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

2014-01-01

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...... events of gene duplication, particularly in Crocodilidae. These findings enhance our understanding of MHC class I evolution and provide a preliminary framework for comparative studies of other non-avian reptiles as well as diversity assessment within Crocodylia....

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

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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.

MHC Class II haplotypes of Colombian Amerindian tribes

Science.gov (United States)

Yunis, Juan J.; Yunis, Edmond J.; Yunis, Emilio

2013-01-01

We analyzed 1041 individuals belonging to 17 Amerindian tribes of Colombia, Chimila, Bari and Tunebo (Chibcha linguistic family), Embera, Waunana (Choco linguistic family), Puinave and Nukak (Maku-Puinave linguistic families), Cubeo, Guanano, Tucano, Desano and Piratapuyo (Tukano linguistic family), Guahibo and Guayabero (Guayabero Linguistic Family), Curripaco and Piapoco (Arawak linguistic family) and Yucpa (Karib linguistic family). for MHC class II haplotypes (HLA-DRB1, DQA1, DQB1). Approximately 90% of the MHC class II haplotypes found among these tribes are haplotypes frequently encountered in other Amerindian tribes. Nonetheless, striking differences were observed among Chibcha and non-Chibcha speaking tribes. The DRB1*04:04, DRB1*04:11, DRB1*09:01 carrying haplotypes were frequently found among non-Chibcha speaking tribes, while the DRB1*04:07 haplotype showed significant frequencies among Chibcha speaking tribes, and only marginal frequencies among non-Chibcha speaking tribes. Our results suggest that the differences in MHC class II haplotype frequency found among Chibcha and non-Chibcha speaking tribes could be due to genetic differentiation in Mesoamerica of the ancestral Amerindian population into Chibcha and non-Chibcha speaking populations before they entered into South America. PMID:23885196

Characterization of 47 MHC class I sequences in Filipino cynomolgus macaques

Science.gov (United States)

Campbell, Kevin J.; Detmer, Ann M.; Karl, Julie A.; Wiseman, Roger W.; Blasky, Alex J.; Hughes, Austin L.; Bimber, Benjamin N.; O’Connor, Shelby L.; O’Connor, David H.

2009-01-01

Cynomolgus macaques (Macaca fascicularis) provide increasingly common models for infectious disease research. Several geographically distinct populations of these macaques from Southeast Asia and the Indian Ocean island of Mauritius are available for pathogenesis studies. Though host genetics may profoundly impact results of such studies, similarities and differences between populations are often overlooked. In this study we identified 47 full-length MHC class I nucleotide sequences in 16 cynomolgus macaques of Filipino origin. The majority of MHC class I sequences characterized (39 of 47) were unique to this regional population. However, we discovered eight sequences with perfect identity and six sequences with close similarity to previously defined MHC class I sequences from other macaque populations. We identified two ancestral MHC haplotypes that appear to be shared between Filipino and Mauritian cynomolgus macaques, notably a Mafa-B haplotype that has previously been shown to protect Mauritian cynomolgus macaques against challenge with a simian/human immunodeficiency virus, SHIV89.6P. We also identified a Filipino cynomolgus macaque MHC class I sequence for which the predicted protein sequence differs from Mamu-B*17 by a single amino acid. This is important because Mamu-B*17 is strongly associated with protection against simian immunodeficiency virus (SIV) challenge in Indian rhesus macaques. These findings have implications for the evolutionary history of Filipino cynomolgus macaques as well as for the use of this model in SIV/SHIV research protocols. PMID:19107381

No evidence for the effect of MHC on male mating success in the brown bear.

Science.gov (United States)

Kuduk, Katarzyna; Babik, Wieslaw; Bellemain, Eva; Valentini, Alice; Zedrosser, Andreas; Taberlet, Pierre; Kindberg, Jonas; Swenson, Jon E; Radwan, Jacek

2014-01-01

Mate choice is thought to contribute to the maintenance of the spectacularly high polymorphism of the Major Histocompatibility Complex (MHC) genes, along with balancing selection from parasites, but the relative contribution of the former mechanism is debated. Here, we investigated the association between male MHC genotype and mating success in the brown bear. We analysed fragments of sequences coding for the peptide-binding region of the highly polymorphic MHC class I and class II DRB genes, while controlling for genome-wide effects using a panel of 18 microsatellite markers. Male mating success did not depend on the number of alleles shared with the female or amino-acid distance between potential mates at either locus. Furthermore, we found no indication of female mating preferences for MHC similarity being contingent on the number of alleles the females carried. Finally, we found no significant association between the number of MHC alleles a male carried and his mating success. Thus, our results provided no support for the role of mate choice in shaping MHC polymorphism in the brown bear.

Natural selection on MHC IIβ in parapatric lake and stream stickleback: Balancing, divergent, both or neither?

Science.gov (United States)

Stutz, William E; Bolnick, Daniel I

2017-09-01

Major histocompatibility complex (MHC) genes encode proteins that play a central role in vertebrates' adaptive immunity to parasites. MHC loci are among the most polymorphic in vertebrates' genomes, inspiring many studies to identify evolutionary processes driving MHC polymorphism within populations and divergence between populations. Leading hypotheses include balancing selection favouring rare alleles within populations, and spatially divergent selection. These hypotheses do not always produce diagnosably distinct predictions, causing many studies of MHC to yield inconsistent or ambiguous results. We suggest a novel strategy to distinguish balancing vs. divergent selection on MHC, taking advantage of natural admixture between parapatric populations. With divergent selection, individuals with immigrant alleles will be more infected and less fit because they are susceptible to novel parasites in their new habitat. With balancing selection, individuals with locally rare immigrant alleles will be more fit (less infected). We tested these contrasting predictions using three-spine stickleback from three replicate pairs of parapatric lake and stream habitats. We found numerous positive and negative associations between particular MHC IIβ alleles and particular parasite taxa. A few allele-parasite comparisons supported balancing selection, and others supported divergent selection between habitats. But, there was no overall tendency for fish with immigrant MHC alleles to be more or less heavily infected. Instead, locally rare MHC alleles (not necessarily immigrants) were associated with heavier infections. Our results illustrate the complex relationship between MHC IIβ allelic variation and spatially varying multispecies parasite communities: different hypotheses may be concurrently true for different allele-parasite combinations. © 2017 John Wiley & Sons Ltd.

Deleterious impact of feto-maternal MHC compatibility on the success of pregnancy in a macaque model.

Science.gov (United States)

Aarnink, Alice; Mee, Edward T; Savy, Nicolas; Congy-Jolivet, Nicolas; Rose, Nicola J; Blancher, Antoine

2014-02-01

The impact of feto-maternal histocompatibility on reproduction has inspired long-lasting debates. However, after the review of numerous articles, the impact of HLA allele sharing within couples on fecundity remains questionable. We decided to explore the impact of major histocompatibility complex (MHC) feto-maternal compatibility on reproduction in a cynomolgus macaque facility composed of animals of Mauritian descent. The Mauritian-derived macaque population presents a very restricted MHC polymorphism (only seven founding haplotypes) due to a strong founding bottleneck effect. The MHC polymorphism was investigated in 237 trios (male, female and offspring) using 17 microsatellite markers distributed across the MHC. Haplotypes were confirmed by segregation analysis. We evaluated the relative frequencies of MHC-compatible and MHC-semi-compatible offspring with the mothers. Among the 237 trios, we selected 42 trios for which the identity of the father is certain and for which the theoretical probabilities of fully compatible and semi-compatible offspring were equal. We found 11 offspring fully compatible and 31 offspring semi-compatible with their respective mother. The observed proportions were clearly outside the interval of confidence of 99 % and therefore most probably resulted from a selection of the semi-compatible offspring during pregnancy. We concluded that MHC fully compatible cynomolgus macaque offspring have a selective survival disadvantage in comparison with offspring inheriting a paternal MHC haplotype differing from maternal haplotypes.

MHC-Dependent Mate Selection within 872 Spousal Pairs of European Ancestry from the Health and Retirement Study

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Zhen Qiao

2018-01-01

Full Text Available Disassortative mating refers to the phenomenon in which individuals with dissimilar genotypes and/or phenotypes mate with one another more frequently than would be expected by chance. Although the existence of disassortative mating is well established in plant and animal species, the only documented example of negative assortment in humans involves dissimilarity at the major histocompatibility complex (MHC locus. Previous studies investigating mating patterns at the MHC have been hampered by limited sample size and contradictory findings. Inspired by the sparse and conflicting evidence, we investigated the role that the MHC region played in human mate selection using genome-wide association data from 872 European American spouses from the Health and Retirement Study (HRS. First, we treated the MHC region as a whole, and investigated genomic similarity between spouses using three levels of genomic variation: single-nucleotide polymorphisms (SNPs, classical human leukocyte antigen (HLA alleles (both four-digit and two-digit classifications, and amino acid polymorphisms. The extent of MHC dissimilarity between spouses was assessed using a permutation approach. Second, we investigated fine scale mating patterns by testing for deviations from random mating at individual SNPs, HLA genes, and amino acids in HLA molecules. Third, we assessed how extreme the spousal relatedness at the MHC region was compared to the rest of the genome, to distinguish the MHC-specific effects from genome-wide effects. We show that neither the MHC region, nor any single SNPs, classic HLA alleles, or amino acid polymorphisms within the MHC region, were significantly dissimilar between spouses relative to non-spouse pairs. However, dissimilarity in the MHC region was extreme relative to the rest of genome for both spousal and non-spouse pairs. Despite the long-standing controversy, our analyses did not support a significant role of MHC dissimilarity in human mate choice.

Thermodynamics of T cell receptor – peptide/MHC interactions: progress and opportunities

Science.gov (United States)

Armstrong, Kathryn M.; Insaidoo, Francis K.; Baker, Brian M.

2013-01-01

αβ T cell receptors (TCR) recognize peptide antigens presented by class I or class II major histocompatibility complex molecules (pMHC). Here we review the use of thermodynamic measurements in the study of TCR-pMHC interactions, with attention to the diversity in binding thermodynamics and how this is related to the variation in TCR-pMHC interfaces. We show that there is no enthalpic or entropic signature for TCR binding; rather, enthalpy and entropy changes vary in a compensatory manner that reflects a narrow free energy window for the interactions that have been characterized. Binding enthalpy and entropy changes do not correlate with structural features such as buried surface area or the number of hydrogen bonds within TCR-pMHC interfaces, possibly reflecting the myriad of contributors to binding thermodynamics, but likely also reflecting a reliance on van’t Hoff over calorimetric measurements and the unaccounted influence of equilibria linked to binding. TCR-pMHC binding heat capacity changes likewise vary considerably. In some cases the heat capacity changes are consistent with conformational differences between bound and free receptors, but there is little data indicating these conformational differences represent the need to organize commonly disordered CDR loops. In this regard, we discuss how thermodynamics may provide additional insight into conformational changes occurring upon TCR binding. Finally, we highlight opportunities for the further use of thermodynamic measurements in the study of TCR-pMHC interactions, not only for understanding TCR binding in general, but for understanding specifics of individual interactions and the engineering of T cell receptors with desired molecular recognition properties. PMID:18496839

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

and it is well suited for high-throughput screening. To exemplify this, we screened a panel of 384 high-affinity peptides binding to the MHC class I molecule, HLA-A*02:01, and observed the rates of dissociation that ranged from 0.1h to 46h depending on the peptide used.......Efficient presentation of peptide-MHC class I complexes to immune T cells depends upon stable peptide-MHC class I interactions. Theoretically, determining the rate of dissociation of a peptide-MHC class I complexes is straightforward; in practical terms, however, generating the accurate and closely...... 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...

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

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......In all vertebrate animals, CD8+ cytotoxic T lymphocytes (CTLs) are controlled by major histocompatibility complex class I (MHC-I) molecules. These are highly polymorphic peptide receptors selecting and presenting endogenously derived epitopes to circulating CTLs. The polymorphism of the MHC...

A comparative analysis of viral peptides presented by contemporary human and chimpanzee MHC class I molecules

NARCIS (Netherlands)

van Deutekom, Hanneke W. M.; Hoof, Ilka; Bontrop, Ronald E.; Keşmir, Can

2011-01-01

Genetic factors such as the MHC influence the immunocompetence of an individual. MHC genes are the most polymorphic genes in primates, which is often interpreted as an adaptation to establish good T cell responses to a wide range of (evolving) pathogens. Chimpanzee MHC (Patr) genes are less

TLR signals induce phagosomal MHC-I delivery from the endosomal recycling compartment to allow cross-presentation

NARCIS (Netherlands)

Nair-Gupta, Priyanka; Baccarini, Alessia; Tung, Navpreet; Seyffer, Fabian; Florey, Oliver; Huang, Yunjie; Banerjee, Meenakshi; Overholtzer, Michael; Roche, Paul A.; Tampé, Robert; Brown, Brian D.; Amsen, Derk; Whiteheart, Sidney W.; Blander, J. Magarian

2014-01-01

Adaptation of the endoplasmic reticulum (ER) pathway for MHC class I (MHC-I) presentation in dendritic cells enables cross-presentation of peptides derived from phagocytosed microbes, infected cells, or tumor cells to CD8 T cells. How these peptides intersect with MHC-I molecules remains poorly

The role of aryl hydrocarbon receptor signaling pathway in cardiotoxicity of acute lead intoxication in vivo and in vitro rat model.

Science.gov (United States)

Ansari, Mushtaq A; Maayah, Zaid H; Bakheet, Saleh A; El-Kadi, Ayman O; Korashy, Hesham M

2013-04-05

Lead (Pb(2+)) is a naturally occurring systemic toxicant heavy metal that affects several organs in the body including the kidneys, liver, and central nervous system. However, Pb(2+)-induced cardiotoxicity has never been investigated yet and the exact mechanism of Pb(2+) associated cardiotoxicity has not been studied. The current study was designed to investigate the potential effect of Pb(2+) to induce cardiotoxicity in vivo and in vitro rat model and to explore the molecular mechanisms and the role of aryl hydrocarbon receptor (AhR) and regulated gene, cytochrome P4501A1 (CYP1A1), in Pb(2+)-mediated cardiotoxicity. For these purposes, Wistar albino rats were treated with Pb(2+) (25, 50 and 100mg/kg, i.p.) for three days and the effects on physiological and histopathological parameters of cardiotoxicity were determined. At the in vitro level, rat cardiomyocyte H9c2 cell lines were incubated with increasing concentration of Pb(2+) (25, 50, and 100 μM) and the expression of hypertrophic genes, α- and β-myosin heavy chain (α-MHC and β-MHC), brain Natriuretic Peptide (BNP), and CYP1A1 were determined at the mRNA and protein levels using real-time PCR and Western blot analysis, respectively. The results showed that Pb(2+) significantly induced cardiotoxicity and heart failure as evidenced by increase cardiac enzymes, lactate dehydrogenase and creatine kinase and changes in histopathology in vivo. In addition, Pb(2+) treatment induced β-MHC and BNP whereas inhibited α-MHC mRNA and protein levels in vivo in a dose-dependent manner. In contrast, at the in vitro level, Pb(2+) treatment induced both β-MHC and α-MHC mRNA levels in time- and dose-dependent manner. Importantly, these changes were accompanied with a proportional increase in the expression of CYP1A1 mRNA and protein expression levels, suggesting a role for the CYP1A1 in cardiotoxicity. The direct evidence for the involvement of CYP1A1 in the induction of cardiotoxicity by Pb(2+) was evidenced by the

New design of MHC class II tetramers to accommodate fundamental principles of antigen presentation.

Science.gov (United States)

Landais, Elise; Romagnoli, Pablo A; Corper, Adam L; Shires, John; Altman, John D; Wilson, Ian A; Garcia, K Christopher; Teyton, Luc

2009-12-15

Direct identification and isolation of Ag-specific T cells became possible with the development of MHC tetramers, based on fluorescent avidins displaying biotinylated peptide-MHC complexes. This approach, extensively used for MHC class I-restricted T cells, has met very limited success with class II peptide-MHC complex tetramers (pMHCT-2) for the detection of CD4(+)-specific T cells. In addition, a very large number of these reagents, although capable of specifically activating T cells after being coated on solid support, is still unable to stain. To try to understand this puzzle and design usable tetramers, we examined each parameter critical for the production of pMHCT-2 using the I-A(d)-OVA system as a model. Through this process, the geometry of peptide-MHC display by avidin tetramers was examined, as well as the stability of rMHC molecules. However, we discovered that the most important factor limiting the reactivity of pMHCT-2 was the display of peptides. Indeed, long peptides, as presented by MHC class II molecules, can be bound to I-A/HLA-DQ molecules in more than one register, as suggested by structural studies. This mode of anchorless peptide binding allows the selection of a broader repertoire on single peptides and should favor anti-infectious immune responses. Thus, beyond the technical improvements that we propose, the redesign of pMHCT-2 will give us the tools to evaluate the real size of the CD4 T cell repertoire and help us in the production and testing of new vaccines.

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

Background: Presentation of peptides on Major Histocompatibility Complex (MHC) molecules is the cornerstone in immune system activation and increased knowledge of the characteristics of MHC ligands and their source proteins is highly desirable. Methodology/Principal Finding: In the present large......-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...

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

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Lund Ole

2009-09-01

Full Text Available Abstract Background The major histocompatibility complex (MHC molecule plays a central role in controlling the adaptive immune response to infections. MHC class I molecules present peptides derived from intracellular proteins to cytotoxic T cells, whereas MHC class II molecules stimulate cellular and humoral immunity through presentation of extracellularly derived peptides to helper T cells. Identification of which peptides will bind a given MHC molecule is thus of great importance for the understanding of host-pathogen interactions, and large efforts have been placed in developing algorithms capable of predicting 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 due to redundant binding core representation. Incorporation of information about the residues flanking the peptide-binding core is shown to significantly improve the prediction accuracy. The method is evaluated on a large-scale benchmark consisting of six independent data sets covering 14 human MHC class II alleles, and is demonstrated to outperform other state-of-the-art MHC class II prediction methods. Conclusion The NN-align method is competitive with the state-of-the-art MHC class II peptide binding prediction algorithms. The method is publicly available at http://www.cbs.dtu.dk/services/NetMHCII-2.0.

The Intensity of Human Body Odors and the MHC: Should We Expect a Link?

OpenAIRE

Claus Wedekind; Thomas Seebeck; Florence Bettens; Alexander J. Paepke

2006-01-01

It is now well established that genes within the major histocompatibility complex (MHC) somehow affect the production of body odors in several vertebrates, including humans. Here we discuss whether variation in the intensity of body odors may be influenced by the MHC. In order to examine this question, we have to control for MHC-linked odor perception on the smeller's side. Such a control is necessary because the perception of pleasantness and intensity seem to be confounded, a...

Structural requirements for the interaction between class II MHC molecules and peptide antigens

DEFF Research Database (Denmark)

Sette, A; Buus, S; Appella, E

1990-01-01

of binding, it is possible to define certain structural features of peptides that are associated with the capacity to bind to a particular MHC specificity (IA(d) or IE(d)); 3) IA(d) and IE(d) molecules recognize different and independent structures on the antigen molecule; 4) only about 10% of the single...... IA(d) and IE(d) molecules and their peptide ligands, we found that some structural characteristics apply to both antigen-MHC interactions. In particular, we found: 1) each MHC molecule is capable of binding many unrelated peptides through the same peptide-binding site; 2) despite this permissiveness...... amino acid substitutions tested on two IA(d)- and IE(d)-binding peptides had significant effect on their MHC-binding capacities, while over 80% of these substitutions significantly impaired T cell recognition of the Ia-peptide complex; 5) based on the segregation between residues that are crucial for T...

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...

Improved methods for predicting peptide binding affinity to MHC class II molecules.

Science.gov (United States)

Jensen, Kamilla Kjaergaard; Andreatta, Massimo; Marcatili, Paolo; Buus, Søren; Greenbaum, Jason A; Yan, Zhen; Sette, Alessandro; Peters, Bjoern; Nielsen, Morten

2018-01-06

Major histocompatibility complex class II (MHC-II) molecules are expressed on the surface of professional antigen-presenting cells where they display peptides to T helper cells, which orchestrate the onset and outcome of many host immune responses. Understanding which peptides will be presented by the MHC-II molecule is therefore important for understanding the activation of T helper cells and can be used to identify T-cell epitopes. We here present updated versions of two MHC-II-peptide binding affinity prediction methods, NetMHCII and NetMHCIIpan. These were constructed using an extended data set of quantitative MHC-peptide binding affinity data obtained from the Immune Epitope Database covering HLA-DR, HLA-DQ, HLA-DP and H-2 mouse molecules. We show that training with this extended data set improved the performance for peptide binding predictions for both methods. Both methods are publicly available at www.cbs.dtu.dk/services/NetMHCII-2.3 and www.cbs.dtu.dk/services/NetMHCIIpan-3.2. © 2018 John Wiley & Sons Ltd.

The MHC molecules of nonmammalian vertebrates

DEFF Research Database (Denmark)

Kaufman, J; Skjoedt, K; Salomonsen, J

1990-01-01

class II distribution. The axolotl has a very poor immune response (as though there are no helper T cells), a wide class II distribution and, for most animals, no cell surface class I molecule. It would be enlightening to understand both the mechanisms for the regulation of the MHC molecules during...

Signal peptide-dependent inhibition of MHC class I heavy chain translation by rhesus cytomegalovirus.

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Colin J Powers

2008-10-01

Full Text Available The US2-11 region of human and rhesus cytomegalovirus encodes a conserved family of glycoproteins that inhibit MHC-I assembly with viral peptides, thus preventing cytotoxic T cell recognition. Since HCMV lacking US2-11 is no longer able to block assembly and transport of MHC-I, we examined whether this is also observed for RhCMV lacking the corresponding region. Unexpectedly, recombinant RhCMV lacking US2-11 was still able to inhibit MHC-I expression in infected fibroblasts, suggesting the presence of an additional MHC-I evasion mechanism. Progressive deletion analysis of RhCMV-specific genomic regions revealed that MHC-I expression is fully restored upon additional deletion of rh178. The protein encoded by this RhCMV-specific open reading frame is anchored in the endoplasmic reticulum membrane. In the presence of rh178, RhCMV prevented MHC-I heavy chain (HC expression, but did not inhibit mRNA transcription or association of HC mRNA with translating ribosomes. Proteasome inhibitors stabilized a HC degradation intermediate in the absence of rh178, but not in its presence, suggesting that rh178 prevents completion of HC translation. This interference was signal sequence-dependent since replacing the signal peptide with that of CD4 or murine HC rendered human HCs resistant to rh178. We have identified an inhibitor of antigen presentation encoded by rhesus cytomegalovirus unique in both its lack of homology to any other known protein and in its mechanism of action. By preventing signal sequence-dependent HC translocation, rh178 acts prior to US2, US3 and US11 which attack MHC-I proteins after protein synthesis is completed. Rh178 is the first viral protein known to interfere at this step of the MHC-I pathway, thus taking advantage of the conserved nature of HC leader peptides, and represents a new mechanism of translational interference.

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

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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.

Quantifying the importance of pMHC valency, total pMHC dose and frequency on nanoparticle therapeutic efficacy.

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Sugarman, Jordan; Tsai, Sue; Santamaria, Pere; Khadra, Anmar

2013-05-01

Nanoparticles (NPs) coated with β-cell-specific peptide major histocompatibility complex (pMHC) class I molecules can effectively restore normoglycemia in spontaneously diabetic nonobese diabetic mice. They do so by expanding pools of cognate memory autoreactive regulatory CD8+ T cells that arise from naive low-avidity T-cell precursors to therapeutic levels. Here we develop our previously constructed mathematical model to explore the effects of compound design parameters (NP dose and pMHC valency) on therapeutic efficacy with the underlying hypothesis that the functional correlates of the therapeutic response (expansion of autoregulatory T cells and deletion of autoantigen-loaded antigen-presenting cells by these T cells) are biphasic. We show, using bifurcation analysis, that the model exhibits a 'resonance'-like behavior for a given range of NP dose in which bistability between the healthy state (possessing zero level of effector T-cell population) and autoimmune state (possessing elevated level of the same population) disappears. A heterogeneous population of model mice subjected to several treatment protocols under these new conditions is conducted to quantify both the average percentage of autoregulatory T cells in responsive and nonresponsive model mice, and the average valency-dependent minimal optimal dose needed for effective therapy. Our results reveal that a moderate increase (≥1.6-fold) in the NP-dependent expansion rate of autoregulatory T-cell population leads to a significant increase in the efficacy and the area corresponding to the effective treatment regimen, provided that NP dose ≥8 μg. We expect the model developed here to generalize to other autoimmune diseases and serve as a computational tool to understand and optimize pMHC-NP-based therapies.

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.

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

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...... on the TCR-mediated increase in [Ca2+]i in Jurkat cells but not on the anti-IgM-mediated activity of Solubo cells. Studies of subpopulations of Jurkat and Solubo cells expressing different levels of MHC-I on their cell surfaces revealed that the TCR- and BCR-mediated increases in [Ca2+]i, respectively, were...

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

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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 (I-Ab) resulted the long-term expression of the retroviral gene product on the surface of MHC class II-expressing bone marrow derived cell types. Mechanistically, tolerance was maintained by the presence of regulatory T cells, which prevented proliferation and cytokine production by alloreactive host T cells. Thus, the introduction of MHC class II genes into bone marrow derived cells through genetic engineering results in tolerance. These results have the potential to extend the clinical applicability of molecular chimerism for tolerance induction. PMID:22833118

Extensive shared polymorphism at non-MHC immune genes in recently diverged North American prairie grouse

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

2018-01-01

Gene polymorphisms shared between recently diverged species are thought to be widespread and most commonly reflect introgression from hybridization or retention of ancestral polymorphism through incomplete lineage sorting. Shared genetic diversity resulting from incomplete lineage sorting is usually maintained for a relatively short period of time, but under strong balancing selection it may persist for millions of years beyond species divergence (balanced trans-species polymorphism), as in the case of the major histocompatibility complex (MHC) genes. However, balancing selection is much less likely to act on non-MHC immune genes. The aim of this study was to investigate the patterns of shared polymorphism and selection at non-MHC immune genes in five grouse species from Centrocercus and Tympanuchus genera. For this purpose, we genotyped five non-MHC immune genes that do not interact directly with pathogens, but are involved in signaling and regulate immune cell growth. In contrast to previous studies with MHC, we found no evidence for balancing selection or balanced trans-species polymorphism among the non-MHC immune genes. No haplotypes were shared between genera and in most cases more similar allelic variants sorted by genus. Between species within genera, however, we found extensive shared polymorphism, which was most likely attributable to introgression or incomplete lineage sorting following recent divergence and large ancestral effective population size (i.e., weak genetic drift). Our study suggests that North American prairie grouse may have attained relatively low degree of reciprocal monophyly at nuclear loci and reinforces the rarity of balancing selection in non-MHC immune genes.

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

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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

Variation in MHC genotypes in two populations of house sparrow (Passer domesticus) with different population histories.

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Borg, Asa Alexandra; Pedersen, Sindre Andre; Jensen, Henrik; Westerdahl, Helena

2011-10-01

Small populations are likely to have a low genetic ability for disease resistance due to loss of genetic variation through inbreeding and genetic drift. In vertebrates, the highest genetic diversity of the immune system is located at genes within the major histocompatibility complex (MHC). Interestingly, parasite-mediated selection is thought to potentially maintain variation at MHC loci even in populations that are monomorphic at other loci. Therefore, general loss of genetic variation in the genome may not necessarily be associated with low variation at MHC loci. We evaluated inter- and intrapopulation variation in MHC genotypes between an inbred (Aldra) and a relatively outbred population (Hestmannøy) of house sparrows (Passer domesticus) in a metapopulation at Helgeland, Norway. Genomic (gDNA) and transcribed (cDNA) alleles of functional MHC class I and IIB loci, along with neutral noncoding microsatellite markers, were analyzed to obtain relevant estimates of genetic variation. We found lower allelic richness in microsatellites in the inbred population, but high genetic variation in MHC class I and IIB loci in both populations. This suggests that also the inbred population could be under balancing selection to maintain genetic variation for pathogen resistance.

It's the peptide-MHC affinity, stupid.

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Kammertoens, Thomas; Blankenstein, Thomas

2013-04-15

Adoptively transferred T cells can reject large established tumors, but recurrence due to escape variants frequently occurs. In this issue of Cancer Cell, Engels et al. demonstrate that the affinity of the target peptide to the MHC molecule determines whether large tumors will relapse following adoptive T cell therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

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

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Beatriz Suárez-Alvarez

2010-04-01

Full Text Available 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.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.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 allograft acceptance.

Epigenetic Mechanisms Regulate MHC and Antigen Processing Molecules in Human Embryonic and Induced Pluripotent Stem Cells

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Suárez-Álvarez, Beatriz; Rodriguez, Ramón M.; Calvanese, Vincenzo; Blanco-Gelaz, Miguel A.; Suhr, Steve T.; Ortega, Francisco; Otero, Jesus; Cibelli, Jose B.; Moore, Harry; Fraga, Mario F.; López-Larrea, Carlos

2010-01-01

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 β2-microglobulin (β2m) 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 β2m 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 allograft acceptance

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 ...

Innate Immune Activation Can Trigger Experimental Spondyloarthritis in HLA-B27/Huβ2m Transgenic Rats

NARCIS (Netherlands)

van Tok, Melissa N.; Satumtira, Nimman; Dorris, Martha; Pots, Desirée; Slobodin, Gleb; van de Sande, Marleen G.; Taurog, Joel D.; Baeten, Dominique L.; van Duivenvoorde, Leonie M.

2017-01-01

Spondyloarthritis (SpA) does not display the typical features of auto-immune disease. Despite the strong association with MHC class I, CD8(+) T cells are not required for disease induction in the HLA-B27/Huβ2m transgenic rats. We used Lewis HLA-B27/Huβ2m transgenic rats [21-3 × 283-2]F1,

MHC Expression on Spleen Lymphocyte Subsets in Genetically Resistant and Susceptible Chickens Infected with Marek's Disease Virus

DEFF Research Database (Denmark)

Dalgaard, Tina; Bøving, Mette K.; Handberg, Kurt

2009-01-01

cytometry for MHC surface expression. In the spleen, constitutive MHC class I surface expression was found to be highest in homozygous B19, lowest in homozygous B21, and intermediate in heterozygous B19/B21 animals. This was observed on CD4(+), CD8(+), and Bu-1(+) splenic lymphocytes. Chickens of all three...... genotypes were subjected to infection with MD virus (GA strain) and spleen samples from infected as well as MHC-matched negative controls were analyzed at 1, 4, and 8 wk post-infection (p.i.). It was observed that MDV induced an increase in MHC class I expression late in the infection. Thus, MHC class I...... was increased on the surface of CD4(+) cells from infected chickens of all genotypes at 4 and 8 wk p.i. compared with negative controls. Also, MHC class I expression was increased on CD8(+) cells from infected chickens of all genotypes at 4 and 8 wk p.i., except for the homozygous B19 animals, that showed...

MHC I stabilizing potential of computer-designed octapeptides.

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Wisniewska, Joanna M; Jäger, Natalie; Freier, Anja; Losch, Florian O; Wiesmüller, Karl-Heinz; Walden, Peter; Wrede, Paul; Schneider, Gisbert; Hiss, Jan A

2010-01-01

Experimental results are presented for 180 in silico designed octapeptide sequences and their stabilizing effects on the major histocompatibility class I molecule H-2K(b). Peptide sequence design was accomplished by a combination of an ant colony optimization algorithm with artificial neural network classifiers. Experimental tests yielded nine H-2K(b) 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.

MHC I Stabilizing Potential of Computer-Designed Octapeptides

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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.

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...... mortality was not observed in any vaccinated mice following infection with the less-invasive Traub strain. However, LCMV Traub infection caused accelerated late mortality in unvaccinated MHC class II-deficient mice; in this case, we observed a strong trend toward delayed mortality in vaccinated mice...

Automated benchmarking of peptide-MHC class I binding predictions

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Trolle, Thomas; Metushi, Imir G.; Greenbaum, Jason A.; Kim, Yohan; Sidney, John; Lund, Ole; Sette, Alessandro; Peters, Bjoern; Nielsen, Morten

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 task. To provide a solid basis on which to compare different prediction tools, we here describe a framework for the automated benchmarking of peptide-MHC class I binding prediction tools. The framework runs weekly benchmarks on data that are newly entered into the Immune Epitope Database (IEDB), giving 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 capability. Upon experimental binding validation, these peptides entered the benchmark study. Results: The benchmark has run for 15 weeks and includes evaluation of 44 datasets covering 17 MHC alleles and more than 4000 peptide-MHC binding measurements. Inspection of the results allows the end-user to make 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 prediction tool developers are invited to participate in the benchmark. Sign-up instructions are available at http://tools.iedb.org/auto_bench/mhci/join. Contact: mniel@cbs.dtu.dk or bpeters@liai.org Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25717196

Constitutive MHC class I molecules negatively regulate TLR-triggered inflammatory responses via the Fps-SHP-2 pathway.

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Xu, Sheng; Liu, Xingguang; Bao, Yan; Zhu, Xuhui; Han, Chaofeng; Zhang, Peng; Zhang, Xuemin; Li, Weihua; Cao, Xuetao

2012-04-22

The molecular mechanisms that fine-tune Toll-like receptor (TLR)-triggered innate inflammatory responses remain to be fully elucidated. Major histocompatibility complex (MHC) molecules can mediate reverse signaling and have nonclassical functions. Here we found that constitutively expressed membrane MHC class I molecules attenuated TLR-triggered innate inflammatory responses via reverse signaling, which protected mice from sepsis. The intracellular domain of MHC class I molecules was phosphorylated by the kinase Src after TLR activation, then the tyrosine kinase Fps was recruited via its Src homology 2 domain to phosphorylated MHC class I molecules. This led to enhanced Fps activity and recruitment of the phosphatase SHP-2, which interfered with TLR signaling mediated by the signaling molecule TRAF6. Thus, constitutive MHC class I molecules engage in crosstalk with TLR signaling via the Fps-SHP-2 pathway and control TLR-triggered innate inflammatory responses.

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

Science.gov (United States)

2012-01-01

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 endangered mammalian

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

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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

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

Science.gov (United States)

Yasukochi, Yoshiki; Kurosaki, Toshifumi; Yoneda, Masaaki; Koike, Hiroko; Satta, Yoko

2012-11-29

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. 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. 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 endangered mammalian species. This result suggests that

Horse cDNA clones encoding two MHC class I genes

Energy Technology Data Exchange (ETDEWEB)

Barbis, D.P.; Maher, J.K.; Stanek, J.; Klaunberg, B.A.; Antczak, D.F.

1994-12-31

Two full-length clones encoding MHC class I genes were isolated by screening a horse cDNA library, using a probe encoding in human HLA-A2.2Y allele. The library was made in the pcDNA1 vector (Invitrogen, San Diego, CA), using mRNA from peripheral blood lymphocytes obtained from a Thoroughbred stallion (No. 0834) homozygous for a common horse MHC haplotype (ELA-A2, -B2, -D2; Antczak et al. 1984; Donaldson et al. 1988). The clones were sequenced, using SP6 and T7 universal primers and horse-specific oligonucleotides designed to extend previously determined sequences.

Detection of new MHC mutations in mice by skin grafting, tumor transplantation and monoclonal antibodies: a comparison

International Nuclear Information System (INIS)

Egorov, I.K.; Egorov, O.S.

1988-01-01

Two mechanisms of major histocompatibility complex (MHC) mutations have been described in mice: gene conversion and homologous but unequal recombination. However, the knowledge of mutations in MHC is incomplete because studies have been limited almost exclusively to two haplotypes, H-2/sup b/ and H-2/sup d/, while hundreds of haplotypes exist in nature; it has been biased by the use of only one procedure of screening for mutation, skin grafting. The authors used three procedures to screen for MHC mutations: (1) conventional techniques of skin grafting, (2) syngeneic tumor transplantation and (3) typing with monoclonal anti-MHC antibodies (mAbs) and complement. The faster technique of tumor transplantation detected mutants similar to those discovered by skin grafting technique. Screening with mAbs allowed us to detect both mutants that are capable of rejecting standard skin grafts and those that are silent in skin grafting tests, and which therefore resulted in a higher apparent mutation frequency. Two mutants of the H-2/sup a/ haplotype were found that carry concomitant class I and class II antigenic alterations. Both MHC mutants silent in skin grafting tests and mutants carrying concomitant class I and class II alterations have never been studied before and are expected to reveal new mechanisms of generating MHC mutations. 1-Ethyl-1-nitrosourea (ENU) failed to induce de novo MHC mutations in our skin grafting series

TLR4-HMGB1 signaling pathway affects the inflammatory reaction of autoimmune myositis by regulating MHC-I.

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Wan, Zemin; Zhang, Xiujuan; Peng, Anping; He, Min; Lei, Zhenhua; Wang, Yunxiu

2016-12-01

To analyze the effects of TLR4 on the expression of the HMGB1, MHC-I and downstream cytokines IL-6 and TNF-α, and to investigate the biological role of the TLR4-HMGB1 signaling pathway in the development of the autoimmune myositis. We built mice models with experimental autoimmune myositis (EAM) and used the inverted screen experiment to measure their muscle endurance; we also examined inflammatory infiltration of muscle tissues after HE staining; and we assessed the expression of MHC-I using immunohistochemistry. In addition, peripheral blood mononuclear cells (PBMC) were extracted and flow cytometry was utilized to detect the effect of IFN-γ on the expression of MHC-I. Furthermore, PBMCs were treated with IFN-γ, anti-TLR4, anti-HMGB1 and anti-MHC-I. Real-time PCR and western blotting were employed to examine the expressions of TLR4, HMGB1 and MHC-I in different groups. The ELISA method was also utilized to detect the expression of the downstream cytokines TNF-α and IL-6. The expressions of TLR4, HMGB1 and MHC-I in muscle tissues from mice with EAM were significantly higher than those in the control group (all Pmyositis inflammation by regulating the expression of MHC-I and other pro-inflammatory cytokines. Copyright © 2016 Elsevier B.V. All rights reserved.

HUBUNGAN ANTARA PERTUMBUHAN DENGAN KEBERADAAN GEN TAHAN PENYAKIT MAJOR HISTOCOMPATIBILITY COMPLEX (MHC PADA IKAN MAS (Cyprinus carpio

Directory of Open Access Journals (Sweden)

Erma Primanita Hayuningtyas

2016-04-01

Full Text Available Wabah penyakit koi herpes virus (KHV di Indonesia yang terjadi sejak tahun 2002 merupakan salah satu faktor yang memicu kemerosotan produksi ikan mas budidaya. Pembentukan strain unggul ikan mas tahan KHV dapat menjadi solusi bagi permasalahan tersebut. Pemilihan genotip ikan mas tahan KHV dengan marka molekuler gen major histocompatibility complex class II (MHC-II, khususnya pada alel Cyca DAB 1*05 akan membantu dalam kegiatan seleksi. Penelitian ini bertujuan untuk mengetahui keberadaan gen MHC-II pada populasi dasar G0 ikan mas strain Rajadanu dan hubungannya dengan pertumbuhan (bobot. Metode deteksi keberadaan gen MHC-II pada dua kelompok ikan dengan ukuran berbeda dilakukan dengan teknik PCR. Hubungan antara pertumbuhan ikan mas dengan persentase kemunculan gen MHC-II dianalisis dengan menggunakan program SPSS (Statistical Package for the Social Sciences, sehingga diperoleh korelasi di antara keduanya. Hasil penelitian menunjukkan bahwa hubungan antara pertumbuhan dengan persentase keberadaan gen MHC-II berkorelasi negatif dengan nilai R = -0,742. Hal ini mengindikasikan bahwa semakin cepat pertumbuhan populasi ikan mas maka semakin sedikit persentase individu yang mempunyai gen MHC-II pada setiap populasi ikan mas. Sehingga populasi ikan mas yang pertumbuhannya lambat memiliki tingkat persentase positif MHC-II lebih tinggi (85,71%-100% dibandingkan populasi ikan mas yang pertumbuhannya cepat (42,86%-85,71%.

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

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

Science.gov (United States)

Nielsen, Morten; Lundegaard, Claus; Lund, Ole

2007-07-04

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. 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. The SMM-align method was shown to outperform other

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

Post-injury stretch promotes recovery in a rat model of muscle damage induced by lengthening contractions.

Science.gov (United States)

Mori, Tomohiro; Agata, Nobuhide; Itoh, Yuta; Inoue-Miyazu, Masumi; Mizumura, Kazue; Sokabe, Masahiro; Taguchi, Toru; Kawakami, Keisuke

2017-06-30

We investigated the cellular mechanisms and therapeutic effect of post-injury stretch on the recovery process from muscle injury induced by lengthening contractions (LC). One day after LC, a single 15-min bout of muscle stretch was applied at an intensity of 3 mNm. The maximal isometric torque was measured before and at 2-21 days after LC. The myofiber size was analyzed at 21 days after LC. Developmental myosin heavy chain-immunoreactive (dMHC-ir) cells, a marker of regenerating myofibers, were observed in the early recovery stage (2-5 days after LC). We observed that LC-induced injury markedly decreased isometric torque and myofiber size, which recovered faster in rats that underwent stretch than in rats that did not. Regenerating myofiber with dMHC-ir cells was observed earlier in rats that underwent stretch. These results indicate that post-injury stretch may facilitate the regeneration and early formation of new myofibers, thereby promoting structural and functional recovery from LC-induced muscle injury.

MHC and non-MHC genes regulate elimination of lymphocytic choriomeningitis virus and antiviral cytotoxic T lymphocyte and delayed-type hypersensitivity mediating T lymphocyte activity in parallel

DEFF Research Database (Denmark)

Thomsen, Allan Randrup; Marker, O

1989-01-01

with regard to all three parameters was recessive, indicating that natural tolerance is not the mechanism explaining non-MHC dependent low responsiveness in this system. The implications of these findings are discussed with specific reference to the role of MHC genes in controlling resistance to infectious......, indicating that both H-2 and non-H-2 genes may influence the elimination of this virus. Differences in virus spread prior to appearance of the immune response could not explain the observed differences in clearance rate. On the other hand, inefficient clearance always correlated with low T cell...

The Missing Link in Epstein-Barr Virus Immune Evasion: the BDLF3 Gene Induces Ubiquitination and Downregulation of Major Histocompatibility Complex Class I (MHC-I) and MHC-II.

Science.gov (United States)

Quinn, Laura L; Williams, Luke R; White, Claire; Forrest, Calum; Zuo, Jianmin; Rowe, Martin

2016-01-01

The ability of Epstein-Barr virus (EBV) to spread and persist in human populations relies on a balance between host immune responses and EBV immune evasion. CD8(+) cells specific for EBV late lytic cycle antigens show poor recognition of target cells compared to immediate early and early antigen-specific CD8(+) cells. This phenomenon is due in part to the early EBV protein BILF1, whose immunosuppressive activity increases with lytic cycle progression. However, published data suggest the existence of a hitherto unidentified immune evasion protein further enhancing protection against late EBV antigen-specific CD8(+) cells. We have now identified the late lytic BDLF3 gene as the missing link accounting for efficient evasion during the late lytic cycle. Interestingly, BDLF3 also contributes to evasion of CD4(+) cell responses to EBV. We report that BDLF3 downregulates expression of surface major histocompatibility complex (MHC) class I and class II molecules in the absence of any effect upon other surface molecules screened, including CD54 (ICAM-1) and CD71 (transferrin receptor). BDLF3 both enhanced internalization of surface MHC molecules and reduced the rate of their appearance at the cell surface. The reduced expression of surface MHC molecules correlated with functional protection against CD8(+) and CD4(+) T cell recognition. The molecular mechanism was identified as BDLF3-induced ubiquitination of MHC molecules and their subsequent downregulation in a proteasome-dependent manner. Immune evasion is a necessary feature of viruses that establish lifelong persistent infections in the face of strong immune responses. EBV is an important human pathogen whose immune evasion mechanisms are only partly understood. Of the EBV immune evasion mechanisms identified to date, none could explain why CD8(+) T cell responses to late lytic cycle genes are so infrequent and, when present, recognize lytically infected target cells so poorly relative to CD8(+) T cells specific for

Stepwise threshold clustering: a new method for genotyping MHC loci using next-generation sequencing technology.

Directory of Open Access Journals (Sweden)

William E Stutz

Full Text Available Genes of the vertebrate major histocompatibility complex (MHC are of great interest to biologists because of their important role in immunity and disease, and their extremely high levels of genetic diversity. Next generation sequencing (NGS technologies are quickly becoming the method of choice for high-throughput genotyping of multi-locus templates like MHC in non-model organisms. Previous approaches to genotyping MHC genes using NGS technologies suffer from two problems:1 a "gray zone" where low frequency alleles and high frequency artifacts can be difficult to disentangle and 2 a similar sequence problem, where very similar alleles can be difficult to distinguish as two distinct alleles. Here were present a new method for genotyping MHC loci--Stepwise Threshold Clustering (STC--that addresses these problems by taking full advantage of the increase in sequence data provided by NGS technologies. Unlike previous approaches for genotyping MHC with NGS data that attempt to classify individual sequences as alleles or artifacts, STC uses a quasi-Dirichlet clustering algorithm to cluster similar sequences at increasing levels of sequence similarity. By applying frequency and similarity based criteria to clusters rather than individual sequences, STC is able to successfully identify clusters of sequences that correspond to individual or similar alleles present in the genomes of individual samples. Furthermore, STC does not require duplicate runs of all samples, increasing the number of samples that can be genotyped in a given project. We show how the STC method works using a single sample library. We then apply STC to 295 threespine stickleback (Gasterosteus aculeatus samples from four populations and show that neighboring populations differ significantly in MHC allele pools. We show that STC is a reliable, accurate, efficient, and flexible method for genotyping MHC that will be of use to biologists interested in a variety of downstream applications.

The peptide-receptive transition state of MHC-1 molecules: Insight from structure and molecular dynamics

Energy Technology Data Exchange (ETDEWEB)

Robinson H.; Mage, M.; Dolan, M.; Wang, R.; Boyd, L.; Revilleza, M.; Natarajan, K.; Myers, N.; Hansen, T.; Margulies, D.

2012-05-01

MHC class I (MHC-I) proteins of the adaptive immune system require antigenic peptides for maintenance of mature conformation and immune function via specific recognition by MHC-I-restricted CD8(+) T lymphocytes. New MHC-I molecules in the endoplasmic reticulum are held by chaperones in a peptide-receptive (PR) transition state pending release by tightly binding peptides. In this study, we show, by crystallographic, docking, and molecular dynamics methods, dramatic movement of a hinged unit containing a conserved 3(10) helix that flips from an exposed 'open' position in the PR transition state to a 'closed' position with buried hydrophobic side chains in the peptide-loaded mature molecule. Crystallography of hinged unit residues 46-53 of murine H-2L(d) MHC-I H chain, complexed with mAb 64-3-7, demonstrates solvent exposure of these residues in the PR conformation. Docking and molecular dynamics predict how this segment moves to help form the A and B pockets crucial for the tight peptide binding needed for stability of the mature peptide-loaded conformation, chaperone dissociation, and Ag presentation.

Can Selective MHC Downregulation Explain the Specificity and Genetic Diversity of NK Cell Receptors?

NARCIS (Netherlands)

Carrillo-Bustamante, Paola; Kesmir, Can; de Boer, Rob J

2015-01-01

Natural killer (NK) cells express inhibiting receptors (iNKRs), which specifically bind MHC-I molecules on the surface of healthy cells. When the expression of MHC-I on the cell surface decreases, which might occur during certain viral infections and cancer, iNKRs lose inhibiting signals and the

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

Ligation of major histocompatibility complex (MHC) class II antigens expressed on antigen-activated human CD4+ T-lymphocytes induces early signal transduction events including the activation of tyrosine kinases, the tyrosine phosphorylation of phospholipase-C gamma 1 and the mobilization...... of 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...... by herbimycin A. MHC class II ligation on B-lymphocytes resulted in cell death, which was both qualitatively distinct from Fas-induced apoptosis and partially protected by herbimycin A pretreatment. Thus, ligation of MHC class II molecules expressed on human lymphocytes stimulates the ZAP-70/p72syk family...

Genetic variation and selection of MHC class I loci differ in two congeneric frogs.

Science.gov (United States)

Kiemnec-Tyburczy, Karen M; Tracy, Karen E; Lips, Karen R; Zamudio, Kelly R

2018-04-01

Major histocompatibility complex (MHC) genes encode proteins in the acquired immune response pathway that often show distinctive selection-driven patterns in wild vertebrate populations. We examined genetic variation and signatures of selection in the MHC class I alpha 1 (A1)- and alpha 2 (A2)-domain encoding exons of two frog congeners [Agalychnis callidryas (n = 20) and A. lemur (n = 20)] from a single locality in Panama. We also investigated how historical demographic processes may have impacted MHC genetic diversity by analyzing a neutral mitochondrial marker. We found that both MHC domains were highly variable in both species, with both species likely expressing three loci. Our analyses revealed different signatures of selection between the two species, most notably that the A. callidryas A2 domain had experienced positive selection while the A2 domain of A. lemur had not. Diversifying selection acted on the same number of A1 and A2 allelic lineages, but on a higher percentage of A1 sites compared to A2 sites. Neutrality tests of mitochondrial haplotypes predominately indicated that the two species were at genetic equilibrium when the samples were collected. In addition, two historical tests of demography indicated both species have had relatively stable population sizes over the past 100,000 years; thus large population size changes are unlikely to have greatly influenced MHC diversity in either species during this time period. In conclusion, our results suggest that the impact of selection on MHC diversity varied between these two closely related species, likely due to a combination of distinct ecological conditions and past pathogenic pressures.

De novo transcriptome assembly facilitates characterisation of fast-evolving gene families, MHC class I in the bank vole (Myodes glareolus).

Science.gov (United States)

Migalska, M; Sebastian, A; Konczal, M; Kotlík, P; Radwan, J

2017-04-01

The major histocompatibility complex (MHC) plays a central role in the adaptive immune response and is the most polymorphic gene family in vertebrates. Although high-throughput sequencing has increasingly been used for genotyping families of co-amplifying MHC genes, its potential to facilitate early steps in the characterisation of MHC variation in nonmodel organism has not been fully explored. In this study we evaluated the usefulness of de novo transcriptome assembly in characterisation of MHC sequence diversity. We found that although de novo transcriptome assembly of MHC I genes does not reconstruct sequences of individual alleles, it does allow the identification of conserved regions for PCR primer design. Using the newly designed primers, we characterised MHC I sequences in the bank vole. Phylogenetic analysis of the partial MHC I coding sequence (2-4 exons) of the bank vole revealed a lack of orthology to MHC I of other Cricetidae, consistent with the high gene turnover of this region. The diversity of expressed alleles was characterised using ultra-deep sequencing of the third exon that codes for the peptide-binding region of the MHC molecule. High allelic diversity was demonstrated, with 72 alleles found in 29 individuals. Interindividual variation in the number of expressed loci was found, with the number of alleles per individual ranging from 5 to 14. Strong signatures of positive selection were found for 8 amino acid sites, most of which are inferred to bind antigens in human MHC, indicating conservation of structure despite rapid sequence evolution.

Features of target cell lysis by class I and class II MHC restricted cytolytic T lymphocytes

International Nuclear Information System (INIS)

Maimone, M.M.; Morrison, L.A.; Braciale, V.L.; Braciale, T.J.

1986-01-01

The lytic activity of influenza virus-specific muvine cytolytic T lymphocyte (CTL) clones that are restricted by either H-2K/D (class I) or H-2I (class II) major histocompatibility (MHC) locus products was compared on an influenza virus-infected target cell expressing both K/D and I locus products. With the use of two in vitro measurements of cytotoxicity, conventional 51 Cr release, and detergent-releasable radiolabeled DNA (as a measure of nuclear disintegration in the early post-lethal hit period), the authors found no difference between class I and class II MHC-restricted CTL in the kinetics of target cell destruction. In addition, class II MHC-restricted antiviral CTL failed to show any lysis of radiolabeled bystander cells. Killing of labeled specific targets by these class II MHC-restricted CTL was also efficiently inhibited by unlabeled specific competitor cells in a cold target inhibition assay. In sum, these data suggest that class I and class II MHC-restricted CTL mediate target cell destruction by an essentially similar direct mechanism

Prediction of the binding affinities of peptides to class II MHC using a regularized thermodynamic model

Directory of Open Access Journals (Sweden)

Mittelmann Hans D

2010-01-01

Full Text Available Abstract Background The binding of peptide fragments of extracellular peptides to class II MHC is a crucial event in the adaptive immune response. Each MHC allotype generally binds a distinct subset of peptides and the enormous number of possible peptide epitopes prevents their complete experimental characterization. Computational methods can utilize the limited experimental data to predict the binding affinities of peptides to class II MHC. Results We have developed the Regularized Thermodynamic Average, or RTA, method for predicting the affinities of peptides binding to class II MHC. RTA accounts for all possible peptide binding conformations using a thermodynamic average and includes a parameter constraint for regularization to improve accuracy on novel data. RTA was shown to achieve higher accuracy, as measured by AUC, than SMM-align on the same data for all 17 MHC allotypes examined. RTA also gave the highest accuracy on all but three allotypes when compared with results from 9 different prediction methods applied to the same data. In addition, the method correctly predicted the peptide binding register of 17 out of 18 peptide-MHC complexes. Finally, we found that suboptimal peptide binding registers, which are often ignored in other prediction methods, made significant contributions of at least 50% of the total binding energy for approximately 20% of the peptides. Conclusions The RTA method accurately predicts peptide binding affinities to class II MHC and accounts for multiple peptide binding registers while reducing overfitting through regularization. The method has potential applications in vaccine design and in understanding autoimmune disorders. A web server implementing the RTA prediction method is available at http://bordnerlab.org/RTA/.

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

New recombinants within the MHC (B-complex) of the chicken

DEFF Research Database (Denmark)

Koch, C; Skjødt, K; Toivanen, A

1983-01-01

In a search for genetic recombinations within the major histocompatibility complex (MHC) of the chicken, the B-complex, the offspring from matings between heterozygous B15/B21 and B4/B6 animals were analysed by red cell agglutination. Among the progeny, 8,912 informative typings were performed...... followed B-F/B-L. The mapping distance between the two loci B-F and B-G is in the range of 0.04 centimorgan. The lack of recombinants separating individual B-F loci in this study and in the studies of others might indicate that chicken MHC is less complex than those of mammalian species, but alternative...

The bioeconomics of controlling an African rodent pest species

OpenAIRE

Skonhoft, Anders; Herwig, Leirs; Andreassen, Harry Peter; Mulungu, Loth S. A.; Stenseth, Nils Christian

2006-01-01

The paper treats the economy of controlling an African pest rodent, the multimammate rat, causing major damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the economic benefits depend on the income from maize production minus the c...

Deep convolutional neural networks for pan-specific peptide-MHC class I binding prediction.

Science.gov (United States)

Han, Youngmahn; Kim, Dongsup

2017-12-28

Computational scanning of peptide candidates that bind to a specific major histocompatibility complex (MHC) can speed up the peptide-based vaccine development process and therefore various methods are being actively developed. Recently, machine-learning-based methods have generated successful results by training large amounts of experimental data. However, many machine learning-based methods are generally less sensitive in recognizing locally-clustered interactions, which can synergistically stabilize peptide binding. Deep convolutional neural network (DCNN) is a deep learning method inspired by visual recognition process of animal brain and it is known to be able to capture meaningful local patterns from 2D images. Once the peptide-MHC interactions can be encoded into image-like array(ILA) data, DCNN can be employed to build a predictive model for peptide-MHC binding prediction. In this study, we demonstrated that DCNN is able to not only reliably predict peptide-MHC binding, but also sensitively detect locally-clustered interactions. Nonapeptide-HLA-A and -B binding data were encoded into ILA data. A DCNN, as a pan-specific prediction model, was trained on the ILA data. The DCNN showed higher performance than other prediction tools for the latest benchmark datasets, which consist of 43 datasets for 15 HLA-A alleles and 25 datasets for 10 HLA-B alleles. In particular, the DCNN outperformed other tools for alleles belonging to the HLA-A3 supertype. The F1 scores of the DCNN were 0.86, 0.94, and 0.67 for HLA-A*31:01, HLA-A*03:01, and HLA-A*68:01 alleles, respectively, which were significantly higher than those of other tools. We found that the DCNN was able to recognize locally-clustered interactions that could synergistically stabilize peptide binding. We developed ConvMHC, a web server to provide user-friendly web interfaces for peptide-MHC class I binding predictions using the DCNN. ConvMHC web server can be accessible via http://jumong.kaist.ac.kr:8080/convmhc

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.

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 wcbg1 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 alpha-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.

MHC class II molecules and tumour immunotherapy

International Nuclear Information System (INIS)

Oven, I.

2005-01-01

Background. Tumour immunotherapy attempts to use the specificity and capability of the immune system to kill malignant cells with a minimum damage to normal tissue. Increasing knowledge of the identity of tumour antigens should help us design more effective therapeutic vaccines. Increasing evidence has demonstrated that MHC class II molecules and CD4+ T cells play important roles in generating and maintaining antitumour immune responses in animal models. These data suggest that it may be necessary to involve both CD4+ and CD8+ T cells for more effective antitumour therapy. Novel strategies have been developed for enhancing T cell responses against cancer by prolonging antigen presentation of dendritic cells to T cells, by the inclusion of MHC class II-restricted tumour antigens and by genetically modifying tumour cells to present antigen to T lymphocytes directly. Conclusions. Vaccines against cancers aim to induce tumour-specific effector T cells that can reduce tumour mass and induce development of tumour-specific T cell memory, that can control tumour relapse. (author)

Fine mapping in the MHC region accounts for 18% additional genetic risk for celiac disease

NARCIS (Netherlands)

Gutierrez-Achury, Javier; Zhernakova, Alexandra; Pulit, Sara L.; Trynka, Gosia; Hunt, Karen A.; Romanos, Jihane; Raychaudhuri, Soumya; van Heel, David A.; Wijmenga, Cisca; de Balcker, Paul I. W.

Although dietary gluten is the trigger for celiac disease, risk is strongly influenced by genetic variation in the major histocompatibility complex (MHC) region. We fine mapped the MHC association signal to identify additional risk factors independent of the HLA-DQA1 and HLA-DQB1 alleles and

Peptide specific expansion of CD8(+) T cells by recombinant plate bound MHC/peptide complexes

DEFF Research Database (Denmark)

Schmidt, Esben G W; Buus, Soren; Thorn, Mette

2009-01-01

to in vitro T cell stimulation was investigated. By use of an antigenic peptide derived from the cytomegalovirus (CMVp) we tested the stimulatory efficacy of recombinant plate bound MHC molecules (PB-MHC), being immobilized in culture plates. A single stimulation of non-adherent peripheral blood mononuclear...

BG1 has a major role in MHC-linked resistance to malignant lymphoma in the chicken.

Science.gov (United States)

Goto, Ronald M; Wang, Yujun; Taylor, Robert L; Wakenell, Patricia S; Hosomichi, Kazuyoshi; Shiina, Takashi; Blackmore, Craig S; Briles, W Elwood; Miller, Marcia M

2009-09-29

Pathogen selection is postulated to drive MHC allelic diversity at loci for antigen presentation. However, readily apparent MHC infectious disease associations are rare in most species. The strong link between MHC-B haplotype and the occurrence of virally induced tumors in the chicken provides a means for defining the relationship between pathogen selection and MHC polymorphism. Here, we verified a significant difference in resistance to gallid herpesvirus-2 (GaHV-2)-induced lymphomas (Marek's disease) conferred by two closely-related recombinant MHC-B haplotypes. We mapped the crossover breakpoints that distinguish these haplotypes to the highly polymorphic BG1 locus. BG1 encodes an Ig-superfamily type I transmembrane receptor-like protein that contains an immunoreceptor tyrosine-based inhibition motif (ITIM), which undergoes phosphorylation and is recognized by Src homology 2 domain-containing protein tyrosine phosphatase (SHP-2). The recombinant haplotypes are identical, except for differences within the BG1 3'-untranslated region (3'-UTR). The 3'-UTR of the BG1 allele associated with increased lymphoma contains a 225-bp insert of retroviral origin and showed greater inhibition of luciferase reporter gene translation compared to the other allele. These findings suggest that BG1 could affect the outcome of GaHV-2 infection through modulation of the lymphoid cell responsiveness to infection, a condition that is critical for GaHV-2 replication and in which the MHC-B haplotype has been previously implicated. This work provides a mechanism by which MHC-B region genetics contributes to the incidence of GaHV-2-induced malignant lymphoma in the chicken and invites consideration of the possibility that similar mechanisms might affect the incidence of lymphomas associated with other oncogenic viral infections.

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

Directory of Open Access Journals (Sweden)

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

Additional file 4: of MHC class II expression and potential antigen-presenting cells in the retina during experimental autoimmune uveitis

OpenAIRE

Lipski, Deborah; Dewispelaere, RÊmi; Foucart, Vincent; Caspers, Laure; Defrance, Matthieu; Bruyns, Catherine; Willermain, François

2017-01-01

Figure S4. MHC class II expression in the retina during classical EAU. Three weeks after immunization, eye cryosections were prepared and stained for MHC class II (green) and IBA1 (red) or endoglin (magenta) detection. Cell nuclei were stained with Hoechst (blue). Each picture was chosen as representative of an experiment conducted on six or more animals. A. MHC class II and IBA1 expression. B. MHC class II and endoglin expression. (PPTX 7276 kb)

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

DEFF Research Database (Denmark)

Nielsen, Morten; Lundegaard, Claus; Lund, Ole

2007-01-01

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...

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

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......, identifying the correct alignment is a crucial part of identifying the core of an MHC class II binding motif. In this context, we wish to describe a novel Gibbs motif sampler method ideally suited for recognizing such weak sequence motifs. The method is based on the Gibbs sampling method, and it incorporates...

Generation of a genomic tiling array of the human Major Histocompatibility Complex (MHC and its application for DNA methylation analysis

Directory of Open Access Journals (Sweden)

Ottaviani Diego

2008-05-01

Full Text Available Abstract Background The major histocompatibility complex (MHC is essential for human immunity and is highly associated with common diseases, including cancer. While the genetics of the MHC has been studied intensively for many decades, very little is known about the epigenetics of this most polymorphic and disease-associated region of the genome. Methods To facilitate comprehensive epigenetic analyses of this region, we have generated a genomic tiling array of 2 Kb resolution covering the entire 4 Mb MHC region. The array has been designed to be compatible with chromatin immunoprecipitation (ChIP, methylated DNA immunoprecipitation (MeDIP, array comparative genomic hybridization (aCGH and expression profiling, including of non-coding RNAs. The array comprises 7832 features, consisting of two replicates of both forward and reverse strands of MHC amplicons and appropriate controls. Results Using MeDIP, we demonstrate the application of the MHC array for DNA methylation profiling and the identification of tissue-specific differentially methylated regions (tDMRs. Based on the analysis of two tissues and two cell types, we identified 90 tDMRs within the MHC and describe their characterisation. Conclusion A tiling array covering the MHC region was developed and validated. Its successful application for DNA methylation profiling indicates that this array represents a useful tool for molecular analyses of the MHC in the context of medical genomics.

Prospects for immunotherapy of MHC class I-deficient tumours

Czech Academy of Sciences Publication Activity Database

Bubeník, Jan

2003-01-01

Roč. 49, č. 3 (2003), s. 95-99 ISSN 0015-5500 Institutional research plan: CEZ:AV0Z5052915 Keywords : MHC class I * immunotherapy Subject RIV: FD - Oncology ; Hematology Impact factor: 0.527, year: 2003

The SysteMHC Atlas project

DEFF Research Database (Denmark)

Shao, Wenguang; Pedrioli, Patrick G. A.; Wolski, Witold

2018-01-01

consisting of consensus spectra calculated from repeat measurements of the same peptide sequence, and links to other proteomics and immunology databases. The SysteMHC Atlas project was created and will be further expanded using a uniform and open computational pipeline that controls the quality of peptide......-scale generation of immunopeptidomic datasets and recent developments in MS-based peptide analysis technologies now support the generation of the required data. Importantly, the availability of diverse immunopeptidomic datasets has resulted in an increasing need to standardize, store and exchange this type of data...

Characterization of MHC-I in the blue tit (Cyanistes caeruleus) reveals low levels of genetic diversity and trans-population evolution across European populations

NARCIS (Netherlands)

Schut, Elske; Rivero-de Aguilar, Juan; Merino, Santiago; Magrath, Michael J. L.; Komdeur, Jan; Westerdahl, Helena

The major histcompatibility complex (MHC) is a vital component of the adaptive immune system in all vertebrates. This study is the first to characterize MHC class I (MHC-I) in blue tits (Cyanistes caeruleus), and we use MHC-I exon 3 sequence data from individuals originating from three locations

MHC class I loaded ligands from breast cancer cell lines: A potential HLA-I-typed antigen collection

Science.gov (United States)

Rozanov, Dmitri V.; Rozanov, Nikita D.; Chiotti, Kami; Reddy, Ashok; Wilmarth, Phillip A.; David, Larry L.; Cha, Seung W.; Woo, Sunghee; Pevzner, Pavel; Bafna, Vineet; Burrows, Gregory G.; Rantala, Juha K.; Levin, Trevor; Anur, Pavana; Johnson-Camacho, Katie; Tabatabaei, Shaadi; Munson, Daniel J.; Bruno, Tullia C.; Slansky, Jill E.; Kappler, John W.; Hirano, Naoto; Boegel, Sebastian; Fox, Bernard A.; Egelston, Colt; Simons, Diana L.; Jimenez, Grecia; Lee, Peter P.; Gray, Joe W.; Spellman, Paul T.

2018-01-01

Breast cancer therapy based on amplifying a patient’s antitumor immune response depends on the availability of appropriate MHC class I-restricted, breast cancer-specific epitopes. To build a catalog of peptides presented by breast cancer cells, we undertook systematic MHC class I immunoprecipitation followed by elution of MHC class I-loaded peptides in breast cancer cell lines. We determined the sequence of 3,196 MHC class I-bound peptides representing 1,921 proteins from a panel of 20 breast cancer cell lines including basal, luminal, and claudin-low subtypes. The data has been deposited to the ProteomeXchange with identifier PXD006406. After removing duplicate peptides, i.e., the same peptide eluted from more than one cell line, the total number of unique peptides was 2,740. Of the unique peptides eluted, more than 1,750 had been previously identified, and of these, sixteen have been shown to be immunogenic. Importantly, only 3 of these immunogenic peptides have been identified in breast cancer cells in earlier studies. MHC class I binding probability of eluted peptides was used to plot the distribution of MHC class I allele-specific peptides in accordance with the binding score for each breast cancer cell line. We also determined that the tested breast cancer cells presented 89 mutation-containing peptides and peptides derived from aberrantly translated genes, 7 of which were shared between four or two different cell lines. Overall, the high throughput identification of MHC class I-loaded peptides is an effective strategy for systematic characterization of cancer peptides, and could be employed for design of multi-peptide anticancer vaccines. PMID:29331515

Characterization of MHC-I in the blue tit (Cyanistes caeruleus) reveals low levels of genetic diversity and trans-population evolution across European populations.

Science.gov (United States)

Schut, Elske; Aguilar, Juan Rivero-de; Merino, Santiago; Magrath, Michael J L; Komdeur, Jan; Westerdahl, Helena

2011-08-01

The major histcompatibility complex (MHC) is a vital component of the adaptive immune system in all vertebrates. This study is the first to characterize MHC class I (MHC-I) in blue tits (Cyanistes caeruleus), and we use MHC-I exon 3 sequence data from individuals originating from three locations across Europe: Spain, the Netherlands to Sweden. Our phylogeny of the 17 blue tit MHC-I alleles contains one allele cluster with low nucleotide diversity compared to the remaining more diverse alleles. We found a significant evidence for balancing selection in the peptide-binding region in the diverse allele group only. No separation according to geographic location was found in the phylogeny of alleles. Although the number of MHC-I loci of the blue tit is comparable to that of other passerine species, the nucleotide diversity of MHC-I appears to be much lower than that of other passerine species, including the closely related great tit (Parus major) and the severely inbred Seychelles warbler (Acrocephalus sechellensis). We believe that this initial MHC-I characterization in blue tits provides an important step towards understanding the mechanisms shaping MHC-I diversity in natural populations.

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

NetMHCpan-4.0: Improved Peptide-MHC Class I Interaction Predictions Integrating Eluted Ligand and Peptide Binding Affinity Data

DEFF Research Database (Denmark)

Jurtz, Vanessa Isabell; Paul, Sinu; Andreatta, Massimo

2017-01-01

by mass spectrometry have been reported containing information about peptide-processing steps in the presentation pathway and the length distribution of naturally presented peptides. In this article, we present NetMHCpan-4.0, a method trained on binding affinity and eluted ligand data leveraging......Cytotoxic T cells are of central importance in the immune system's response to disease. They recognize defective cells by binding to peptides presented on the cell surface by MHC class I molecules. Peptide binding to MHC molecules is the single most selective step in the Ag-presentation pathway....... Therefore, in the quest for T cell epitopes, the prediction of peptide binding to MHC molecules has attracted widespread attention. In the past, predictors of peptide-MHC interactions have primarily been trained on binding affinity data. Recently, an increasing number of MHC-presented peptides identified...

Inhibition of MHC class I is a virulence factor in herpes simplex virus infection of mice.

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Mark T Orr

2005-09-01

Full Text Available Herpes simplex virus (HSV has a number of genes devoted to immune evasion. One such gene, ICP47, binds to the transporter associated with antigen presentation (TAP 1/2 thereby preventing transport of viral peptides into the endoplasmic reticulum, loading of peptides onto nascent major histocompatibility complex (MHC class I molecules, and presentation of peptides to CD8 T cells. However, ICP47 binds poorly to murine TAP1/2 and so inhibits antigen presentation by MHC class I in mice much less efficiently than in humans, limiting the utility of murine models to address the importance of MHC class I inhibition in HSV immunopathogenesis. To address this limitation, we generated recombinant HSVs that efficiently inhibit antigen presentation by murine MHC class I. These recombinant viruses prevented cytotoxic T lymphocyte killing of infected cells in vitro, replicated to higher titers in the central nervous system, and induced paralysis more frequently than control HSV. This increase in virulence was due to inhibition of antigen presentation to CD8 T cells, since these differences were not evident in MHC class I-deficient mice or in mice in which CD8 T cells were depleted. Inhibition of MHC class I by the recombinant viruses did not impair the induction of the HSV-specific CD8 T-cell response, indicating that cross-presentation is the principal mechanism by which HSV-specific CD8 T cells are induced. This inhibition in turn facilitates greater viral entry, replication, and/or survival in the central nervous system, leading to an increased incidence of paralysis.

MHC classⅠ gene in two duck lines

Indian Academy of Sciences (India)

Navya

Weishan Ma duck (WS) is the eugenic endemic breed, one of the four famous ducks in China, as well Cherry Valley duck (CV) is the largest number of breeding variety. WS is egg strain and CV is meat type. The two duck lines mainly support the. Chinese waterfowl industry. In this study, MHC class Ⅰ genes of WS and CV ...

Do farming practices influence population dynamics of rodents?

DEFF Research Database (Denmark)

Massawe, A W; Rwamugira, W; Leirs, Herwig

2007-01-01

A capture-mark-recapture study was conducted in crop fields in Morogoro, Tanzania, to investigate how the population dynamics of multimammate field rats, Mastomys natalensis, was influenced by the commonly practised land preparation methods and cropping systems. Two land preparation methods (trac...... practices. In maize fields in Tanzania, the crop is most susceptible to damage by M. natalensis in the first 2 weeks after planting, and therefore, lower densities of rodents will result into lower crop damage in tractor ploughed fields....

Expression and phylogenetic analyses reveal paralogous lineages of putatively classical and non-classical MHC-I genes in three sparrow species (Passer).

Science.gov (United States)

Drews, Anna; Strandh, Maria; Råberg, Lars; Westerdahl, Helena

2017-06-26

The Major Histocompatibility Complex (MHC) plays a central role in immunity and has been given considerable attention by evolutionary ecologists due to its associations with fitness-related traits. Songbirds have unusually high numbers of MHC class I (MHC-I) genes, but it is not known whether all are expressed and equally important for immune function. Classical MHC-I genes are highly expressed, polymorphic and present peptides to T-cells whereas non-classical MHC-I genes have lower expression, are more monomorphic and do not present peptides to T-cells. To get a better understanding of the highly duplicated MHC genes in songbirds, we studied gene expression in a phylogenetic framework in three species of sparrows (house sparrow, tree sparrow and Spanish sparrow), using high-throughput sequencing. We hypothesize that sparrows could have classical and non-classical genes, as previously indicated though never tested using gene expression. The phylogenetic analyses reveal two distinct types of MHC-I alleles among the three sparrow species, one with high and one with low level of polymorphism, thus resembling classical and non-classical genes, respectively. All individuals had both types of alleles, but there was copy number variation both within and among the sparrow species. However, the number of highly polymorphic alleles that were expressed did not vary between species, suggesting that the structural genomic variation is counterbalanced by conserved gene expression. Overall, 50% of the MHC-I alleles were expressed in sparrows. Expression of the highly polymorphic alleles was very variable, whereas the alleles with low polymorphism had uniformly low expression. Interestingly, within an individual only one or two alleles from the polymorphic genes were highly expressed, indicating that only a single copy of these is highly expressed. Taken together, the phylogenetic reconstruction and the analyses of expression suggest that sparrows have both classical and non

Haematopoietic depletion in vaccine-induced neonatal pancytopenia depends on both the titre and specificity of alloantibody and levels of MHC I expression.

Science.gov (United States)

Bell, Charlotte R; MacHugh, Niall D; Connelley, Timothy K; Degnan, Kathryn; Morrison, W Ivan

2015-07-09

Bovine Neonatal Pancytopenia (BNP) is a disease of calves characterised by haematopoietic depletion, mediated by ingestion of alloantibodies in colostrum. It has been linked epidemiologically to vaccination of the dams of affected calves with a particular vaccine (Pregsure) containing a novel adjuvant. Evidence suggests that BNP-alloantibodies are directed against MHC I molecules, induced by contaminant bovine cellular material from Madin-Darby Bovine Kidney (MDBK) cells used in the vaccine's production. We aimed to investigate the specificity of BNP-alloantibody for bovine MHC I alleles, particularly those expressed by MDBK cells, and whether depletion of particular cell types is due to differential MHC I expression levels. A complement-mediated cytotoxicity assay was used to assess functional serum alloantibody titres in BNP-dams, Pregsure-vaccinated dams with healthy calves, cows vaccinated with an alternative product and unvaccinated controls. Alloantibody specificity was investigated using transfected mouse lines expressing the individual MHC I alleles identified from MDBK cells and MHC I-defined bovine leukocyte lines. All BNP-dams and 50% of Pregsure-vaccinated cows were shown to have MDBK-MHC I specific alloantibodies, which cross-reacted to varying degrees with other MHC I genotypes. MHC I expression levels on different blood cell types, assessed by flow cytometry, were found to correlate with levels of alloantibody-mediated damage in vitro and in vivo. Alloantibody-killed bone marrow cells were shown to express higher levels of MHC I than undamaged cells. The results provide evidence that MHC I-specific alloantibodies play a dominant role in the pathogenesis of BNP. Haematopoietic depletion was shown to be dependent on the titre and specificity of alloantibody produced by individual cows and the density of surface MHC I expression by different cell types. Collectively, the results support the hypothesis that MHC I molecules originating from MDBK cells

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.

MHC-I affects infection intensity but not infection status with a frequent avian malaria parasite in blue tits.

Science.gov (United States)

Westerdahl, Helena; Stjernman, Martin; Råberg, Lars; Lannefors, Mimi; Nilsson, Jan-Åke

2013-01-01

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.

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 ...... MHC class I molecules with biological activity. We report here the use of a bacterial expression system to produce the recombinant single-chain MHC molecules based on a specific allele Sasa-UBA*0301. This particular allele was selected because previous work has shown its association...... 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......, the recombinant proteins were purified by affinity chromatography using mAb against beta2m and alpha3. Eluates were analyzed by Western blot and refolded by the removal of denaturant. The correct folding was confirmed by measuring its binding capacity against mAb produced to recognize the native form of MHC...

Extreme MHC class I diversity in the sedge warbler (Acrocephalus schoenobaenus); selection patterns and allelic divergence suggest that different genes have different functions.

Science.gov (United States)

Biedrzycka, Aleksandra; O'Connor, Emily; Sebastian, Alvaro; Migalska, Magdalena; Radwan, Jacek; Zając, Tadeusz; Bielański, Wojciech; Solarz, Wojciech; Ćmiel, Adam; Westerdahl, Helena

2017-07-05

Recent work suggests that gene duplications may play an important role in the evolution of immunity genes. Passerine birds, and in particular Sylvioidea warblers, have highly duplicated major histocompatibility complex (MHC) genes, which are key in immunity, compared to other vertebrates. However, reasons for this high MHC gene copy number are yet unclear. High-throughput sequencing (HTS) allows MHC genotyping even in individuals with extremely duplicated genes. This HTS data can reveal evidence of selection, which may help to unravel the putative functions of different gene copies, i.e. neofunctionalization. We performed exhaustive genotyping of MHC class I in a Sylvioidea warbler, the sedge warbler, Acrocephalus schoenobaenus, using the Illumina MiSeq technique on individuals from a wild study population. The MHC diversity in 863 genotyped individuals by far exceeds that of any other bird species described to date. A single individual could carry up to 65 different alleles, a large proportion of which are expressed (transcribed). The MHC alleles were of three different lengths differing in evidence of selection, diversity and divergence within our study population. Alleles without any deletions and alleles containing a 6 bp deletion showed characteristics of classical MHC genes, with evidence of multiple sites subject to positive selection and high sequence divergence. In contrast, alleles containing a 3 bp deletion had no sites subject to positive selection and had low divergence. Our results suggest that sedge warbler MHC alleles that either have no deletion, or contain a 6 bp deletion, encode classical antigen presenting MHC molecules. In contrast, MHC alleles containing a 3 bp deletion may encode molecules with a different function. This study demonstrates that highly duplicated MHC genes can be characterised with HTS and that selection patterns can be useful for revealing neofunctionalization. Importantly, our results highlight the need to consider the

Forming a complex with MHC class I molecules interferes with mouse CD1d functional expression.

Directory of Open Access Journals (Sweden)

Renukaradhya J Gourapura

Full Text Available CD1d molecules are structurally similar to MHC class I, but present lipid antigens as opposed to peptides. Here, we show that MHC class I molecules physically associate with (and regulate the functional expression of mouse CD1d on the surface of cells. Low pH (3.0 acid stripping of MHC class I molecules resulted in increased surface expression of murine CD1d on antigen presenting cells as well as augmented CD1d-mediated antigen presentation to NKT cells. Consistent with the above results, TAP1-/- mice were found to have a higher percentage of type I NKT cells as compared to wild type mice. Moreover, bone marrow-derived dendritic cells from TAP1-/- mice showed increased antigen presentation by CD1d compared to wild type mice. Together, these results suggest that MHC class I molecules can regulate NKT cell function, in part, by masking CD1d.

The mRNA expression profile of metabolic genes relative to MHC isoform pattern in human skeletal muscles

DEFF Research Database (Denmark)

Plomgaard, Peter; Penkowa, Milena; Leick, Lotte

2006-01-01

The metabolic profile of rodent muscle is generally reflected in the myosin heavy chain (MHC) fiber-type composition. The present study was conducted to test the hypothesis that metabolic gene expression is not tightly coupled with MHC fiber-type composition for all genes in human skeletal muscle....... Triceps brachii, vastus lateralis quadriceps, and soleus muscle biopsies were obtained from normally physically active, healthy, young male volunteers, because these muscles are characterized by different fiber-type compositions. As expected, citrate synthase and 3-hydroxyacyl dehydrogenase activity...... of a broad range of metabolic genes. The triceps muscle had two- to fivefold higher MHC IIa, phosphofructokinase, and LDH A mRNA content and two- to fourfold lower MHC I, lipoprotein lipase, CD36, hormone-sensitive lipase, and LDH B and hexokinase II mRNA than vastus lateralis or soleus. Interestingly...

MHC class II tetramers made from isolated recombinant α and β chains refolded with affinity-tagged peptides

DEFF Research Database (Denmark)

Braendstrup, Peter; Justesen, Sune Frederik Lamdahl; Osterbye, Thomas

2013-01-01

Targeting CD4+ T cells through their unique antigen-specific, MHC class II-restricted T cell receptor makes MHC class II tetramers an attractive strategy to identify, validate and manipulate these cells at the single cell level. Currently, generating class II tetramers is a specialized undertaking...... effectively limiting their use and emphasizing the need for improved methods of production. Using class II chains expressed individually in E. coli as versatile recombinant reagents, we have previously generated peptide-MHC class II monomers, but failed to generate functional class II tetramers. Adding...... a monomer purification principle based upon affinity-tagged peptides, we here provide a robust method to produce class II tetramers and demonstrate staining of antigen-specific CD4+ T cells. We also provide evidence that both MHC class II and T cell receptor molecules largely accept affinity-tagged peptides...

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

International Nuclear Information System (INIS)

Sharrow, S.O.; Mathieson, B.J.; Singer, A.

1981-01-01

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

High-throughput discovery of T cell epitopes in type 1 diabetes using DNA barcode labelledpeptide-MHC multimers

DEFF Research Database (Denmark)

Lyngaa, Rikke Birgitte; Bentzen, Amalie Kai; Overgaard, A. Julie

2016-01-01

applying a novel technology where the selection of MHC-multimer binding T cells is followed by amplification and sequencing of MHC multimer-associated DNA barcodes revealing their recognition. This technique enables simultaneous detection of >1000 specificities. Identifying post translational modifications...

Immunohistochemical detection and correlation between MHC antigen and cell-mediated immune system in recurrent glioma by APAAP method.

Science.gov (United States)

Miyagi, K; Ingram, M; Techy, G B; Jacques, D B; Freshwater, D B; Sheldon, H

1990-09-01

As part of an on-going clinical trial of immunotherapy for recurrent malignant gliomas, using alkaline phosphatase-anti-alkaline phosphatase method with monoclonal antibodies, we investigated the correlation between expression of the major histocompatibility complex (MHC) and the subpopulation of tumor-infiltrating lymphocytes (TILs) in 38 glioma specimens (20 grade IV, 11 grade III, and 7 grade II) from 33 patients. Thirty specimens (78.9%) were positive to class I MHC antigen and 20 (52.6%) were positive to class II MHC antigen. The correlations between class I MHC antigen expression and the number of infiltrating T8 (p less than 0.01), and also between class II MHC antigen expression and the number of infiltrating T4 (p less than 0.05) were significant. We conclude that TILs are the result of immunoreaction (host-defense mechanism). 31.6% of specimens had perivascular infiltration of T cells. The main infiltrating lymphocyte subset in moderate to marked perivascular cuffing was T4. Our results may indicate that lack of MHC antigen on the glioma cell surface has a share in the poor immunogenicity in glioma-bearing patients. In addition, considering the effector/target ratio, the number of infiltrating lymphocytes against glioma cells was too small, so the immunological intervention seems to be essential in glioma therapy. Previous radiation therapy and chemotherapy, including steroid therapy, did not influence lymphocyte and macrophage infiltration.

Evolution of MHC class I genes in the endangered loggerhead sea turtle (Caretta caretta) revealed by 454 amplicon sequencing.

Science.gov (United States)

Stiebens, Victor A; Merino, Sonia E; Chain, Frédéric J J; Eizaguirre, Christophe

2013-04-30

In evolutionary and conservation biology, parasitism is often highlighted as a major selective pressure. To fight against parasites and pathogens, genetic diversity of the immune genes of the major histocompatibility complex (MHC) are particularly important. However, the extensive degree of polymorphism observed in these genes makes it difficult to conduct thorough population screenings. We utilized a genotyping protocol that uses 454 amplicon sequencing to characterize the MHC class I in the endangered loggerhead sea turtle (Caretta caretta) and to investigate their evolution at multiple relevant levels of organization. MHC class I genes revealed signatures of trans-species polymorphism across several reptile species. In the studied loggerhead turtle individuals, it results in the maintenance of two ancient allelic lineages. We also found that individuals carrying an intermediate number of MHC class I alleles are larger than those with either a low or high number of alleles. Multiple modes of evolution seem to maintain MHC diversity in the loggerhead turtles, with relatively high polymorphism for an endangered species.

Red Queen Processes Drive Positive Selection on Major Histocompatibility Complex (MHC Genes.

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Maciej Jan Ejsmond

2015-11-01

Full Text Available Major Histocompatibility Complex (MHC genes code for proteins involved in the incitation of the adaptive immune response in vertebrates, which is achieved through binding oligopeptides (antigens of pathogenic origin. Across vertebrate species, substitutions of amino acids at sites responsible for the specificity of antigen binding (ABS are positively selected. This is attributed to pathogen-driven balancing selection, which is also thought to maintain the high polymorphism of MHC genes, and to cause the sharing of allelic lineages between species. However, the nature of this selection remains controversial. We used individual-based computer simulations to investigate the roles of two phenomena capable of maintaining MHC polymorphism: heterozygote advantage and host-pathogen arms race (Red Queen process. Our simulations revealed that levels of MHC polymorphism were high and driven mostly by the Red Queen process at a high pathogen mutation rate, but were low and driven mostly by heterozygote advantage when the pathogen mutation rate was low. We found that novel mutations at ABSs are strongly favored by the Red Queen process, but not by heterozygote advantage, regardless of the pathogen mutation rate. However, while the strong advantage of novel alleles increased the allele turnover rate, under a high pathogen mutation rate, allelic lineages persisted for a comparable length of time under Red Queen and under heterozygote advantage. Thus, when pathogens evolve quickly, the Red Queen is capable of explaining both positive selection and long coalescence times, but the tension between the novel allele advantage and persistence of alleles deserves further investigation.

MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency

NARCIS (Netherlands)

Buch, Thorsten; Polic, Bojan; Clausen, Björn E.; Weiss, Susanne; Akilli-Ozturk, Ozlem; Chang, Cheong-Hee; Flavell, Richard; Schulz, Ansgar; Jonjic, Stipan; Waisman, Ari; Förster, Irmgard

2006-01-01

MHC class II (MHCII) deficiency or bare lymphocyte syndrome (BLS) is a severe immunodeficiency characterized by deficient T helper (Th)-cell-dependent immunity. The disease is caused by defects of the MHCII promoter complex resulting in low or absent MHCII expression. We demonstrate in a murine

Peptide-MHC-based nanomedicines for autoimmunity function as T-cell receptor microclustering devices

Science.gov (United States)

Singha, Santiswarup; Shao, Kun; Yang, Yang; Clemente-Casares, Xavier; Solé, Patricia; Clemente, Antonio; Blanco, Jesús; Dai, Qin; Song, Fayi; Liu, Shang Wan; Yamanouchi, Jun; Umeshappa, Channakeshava Sokke; Nanjundappa, Roopa Hebbandi; Detampel, Pascal; Amrein, Matthias; Fandos, César; Tanguay, Robert; Newbigging, Susan; Serra, Pau; Khadra, Anmar; Chan, Warren C. W.; Santamaria, Pere

2017-07-01

We have shown that nanoparticles (NPs) can be used as ligand-multimerization platforms to activate specific cellular receptors in vivo. Nanoparticles coated with autoimmune disease-relevant peptide-major histocompatibility complexes (pMHC) blunted autoimmune responses by triggering the differentiation and expansion of antigen-specific regulatory T cells in vivo. Here, we define the engineering principles impacting biological activity, detail a synthesis process yielding safe and stable compounds, and visualize how these nanomedicines interact with cognate T cells. We find that the triggering properties of pMHC-NPs are a function of pMHC intermolecular distance and involve the sustained assembly of large antigen receptor microclusters on murine and human cognate T cells. These compounds show no off-target toxicity in zebrafish embryos, do not cause haematological, biochemical or histological abnormalities, and are rapidly captured by phagocytes or processed by the hepatobiliary system. This work lays the groundwork for the design of ligand-based NP formulations to re-program in vivo cellular responses using nanotechnology.

RSCA genotyping of MHC for high-throughput evolutionary studies in the model organism three-spined stickleback Gasterosteus aculeatus

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Lenz, Tobias L; Eizaguirre, Christophe; Becker, Sven; Reusch, Thorsten BH

2009-01-01

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. PMID:19291291

RSCA genotyping of MHC for high-throughput evolutionary studies in the model organism three-spined stickleback Gasterosteus aculeatus

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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.

Generation of murine tumor cell lines deficient in MHC molecule surface expression using the CRISPR/Cas9 system.

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Krishna Das

Full Text Available In this study, the CRISPR/Cas9 technology was used to establish murine tumor cell lines, devoid of MHC I or MHC II surface expression, respectively. The melanoma cell line B16F10 and the murine breast cancer cell line EO-771, the latter stably expressing the tumor antigen NY-BR-1 (EO-NY, were transfected with an expression plasmid encoding a β2m-specific single guide (sgRNA and Cas9. The resulting MHC I negative cells were sorted by flow cytometry to obtain single cell clones, and loss of susceptibility of peptide pulsed MHC I negative clones to peptide-specific CTL recognition was determined by IFNγ ELISpot assay. The β2m knockout (KO clones did not give rise to tumors in syngeneic mice (C57BL/6N, unless NK cells were depleted, suggesting that outgrowth of the β2m KO cell lines was controlled by NK cells. Using sgRNAs targeting the β-chain encoding locus of the IAb molecule we also generated several B16F10 MHC II KO clones. Peptide loaded B16F10 MHC II KO cells were insusceptible to recognition by OT-II cells and tumor growth was unaltered compared to parental B16F10 cells. Thus, in our hands the CRISPR/Cas9 system has proven to be an efficient straight forward strategy for the generation of MHC knockout cell lines. Such cell lines could serve as parental cells for co-transfection of compatible HLA alleles together with human tumor antigens of interest, thereby facilitating the generation of HLA matched transplantable tumor models, e.g. in HLAtg mouse strains of the newer generation, lacking cell surface expression of endogenous H2 molecules. In addition, our tumor cell lines established might offer a useful tool to investigate tumor reactive T cell responses that function independently from MHC molecule surface expression by the tumor.

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)

Sethi, D.K.; Heroux, A.; Schubert, D. A.; Anders, A.-K.; Bonsor, D. A.; Thomas, C. P.; Sundberg, E. J.; Pyrdol, J.; Wucherpfennig, K. W.

2011-01-17

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.

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.

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

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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

Immunotherapy of MHC class I-deficient tumours and epigenetic upregulation of MHC class I molecules on tumour cells

Czech Academy of Sciences Publication Activity Database

Reiniš, Milan; Manning, Jasper; Indrová, Marie; Přibylová, Hana; Bieblová, Jana; Šímová, Jana; Bubeník, Jan

2007-01-01

Roč. 20, Suppl. 1 (2007), S29-S29 ISSN 1107-3756. [World Congress on Advances in Oncology /12./ and International Symposium on Molecular Medicine /10./. 11.10.2007-12.10.2007, Hernissos] R&D Projects: GA ČR GA301/04/0492; GA ČR GA301/07/1410 Institutional research plan: CEZ:AV0Z50520514 Keywords : Immunotherapy * MHC I-deficient tumours * epigenetics Subject RIV: EB - Genetics ; Molecular Biology

Characteristics of MHC class I genes in house sparrows Passer domesticus as revealed by long cDNA transcripts and amplicon sequencing.

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Karlsson, Maria; Westerdahl, Helena

2013-08-01

In birds the major histocompatibility complex (MHC) organization differs both among and within orders; chickens Gallus gallus of the order Galliformes have a simple arrangement, while many songbirds of the order Passeriformes have a more complex arrangement with larger numbers of MHC class I and II genes. Chicken MHC genes are found at two independent loci, classical MHC-B and non-classical MHC-Y, whereas non-classical MHC genes are yet to be verified in passerines. Here we characterize MHC class I transcripts (α1 to α3 domain) and perform amplicon sequencing using a next-generation sequencing technique on exon 3 from house sparrow Passer domesticus (a passerine) families. Then we use phylogenetic, selection, and segregation analyses to gain a better understanding of the MHC class I organization. Trees based on the α1 and α2 domain revealed a distinct cluster with short terminal branches for transcripts with a 6-bp deletion. Interestingly, this cluster was not seen in the tree based on the α3 domain. 21 exon 3 sequences were verified in a single individual and the average numbers within an individual were nine and five for sequences with and without a 6-bp deletion, respectively. All individuals had exon 3 sequences with and without a 6-bp deletion. The sequences with a 6-bp deletion have many characteristics in common with non-classical MHC, e.g., highly conserved amino acid positions were substituted compared with the other alleles, low nucleotide diversity and just a single site was subject to positive selection. However, these alleles also have characteristics that suggest they could be classical, e.g., complete linkage and absence of a distinct cluster in a tree based on the α3 domain. Thus, we cannot determine for certain whether or not the alleles with a 6-bp deletion are non-classical based on our present data. Further analyses on segregation patterns of these alleles in combination with dating the 6-bp deletion through MHC characterization across the

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

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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.

Expression, refolding and crystallization of murine MHC class I H-2Db in complex with human β2-microglobulin

International Nuclear Information System (INIS)

Sandalova, Tatyana; Michaëlsson, Jakob; Harris, Robert A.; Ljunggren, Hans-Gustaf; Kärre, Klas; Schneider, Gunter; Achour, Adnane

2005-01-01

Mouse MHC class I H-2Db in complex with human β2m and the LCMV-derived peptide gp33 has been produced and crystallized. Resolution of the structure of this complex combined with the structural comparison with the previously solved crystal structure of H-2Db/mβ2m/gp33 should lead to a better understanding of how the β2m subunit affects the overall conformation of MHC complexes as well as the stability of the presented peptides. β 2 -Microglobulin (β 2 m) is non-covalently linked to the major histocompatibility (MHC) class I heavy chain and interacts with CD8 and Ly49 receptors. Murine MHC class I can bind human β 2 m (hβ 2 m) and such hybrid molecules are often used in structural and functional studies. The replacement of mouse β 2 m (mβ 2 m) by hβ 2 m has important functional consequences for MHC class I complex stability and specificity, but the structural basis for this is unknown. To investigate the impact of species-specific β 2 m subunits on MHC class I conformation, murine MHC class I H-2D b in complex with hβ 2 m and the peptide gp33 derived from lymphocytic choriomeningitis virus (LCMV) has been expressed, refolded in vitro and crystallized. Crystals containing two complexes per asymmetric unit and belonging to the space group P2 1 , with unit-cell parameters a = 68.1, b = 65.2, c = 101.9 Å, β = 102.4°, were obtained

Design of Peptide Immunotherapies for MHC Class-II-Associated Autoimmune Disorders

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Masha Fridkis-Hareli

2013-01-01

Full Text Available Autoimmune disorders, that occur when autoreactive immune cells are induced to activate their responses against self-tissues, affect one percent of the world population and represent one of the top 10 leading causes of death. The major histocompatibility complex (MHC is a principal susceptibility locus for many human autoimmune diseases, in which self-tissue antigens providing targets for pathogenic lymphocytes are bound to HLA molecules encoded by disease-associated alleles. In spite of the attempts to design strategies for inhibition of antigen presentation targeting the MHC-peptide/TCR complex via generation of blocking antibodies, altered peptide ligands (APL, or inhibitors of costimulatory molecules, potent therapies with minimal side effects have yet to be developed. Copaxone (glatiramer acetate, GA is a random synthetic amino acid copolymer that reduces the relapse rate by about 30% in relapsing-remitting multiple sclerosis (MS patients. Based on the elucidated binding motifs of Copaxone and of the anchor residues of the immunogenic myelin basic protein (MBP peptide to HLA-DR molecules, novel copolymers have been designed and proved to be more effective in suppressing MS-like disease in mice. In this report, we describe the rationale for design of second-generation synthetic random copolymers as candidate drugs for a number of MHC class-II-associated autoimmune disorders.

Tumour MHC class I downregulation and immunotherapy (Review)

Czech Academy of Sciences Publication Activity Database

Bubeník, Jan

2003-01-01

Roč. 10, č. 6 (2003), s. 2005-2008 ISSN 1021-335X R&D Projects: GA MZd NC7148; GA ČR GA301/01/0985; GA AV ČR IAA5052203 Institutional research plan: CEZ:AV0Z5052915 Keywords : tumour vaccines * MHC class I downregulation Subject RIV: FD - Oncology ; Hematology Impact factor: 1.256, year: 2003

MHC-I Ligand Discovery Using Targeted Database Searches of Mass Spectrometry Data: Implications for T-Cell Immunotherapies

DEFF Research Database (Denmark)

Murphy, J. Patrick; Konda, Prathyusha; Kowalewski, Daniel J.

2017-01-01

Class I major histocompatibility complex (MHC-I)-bound peptide ligands dictate the activation and specificity of CD8+ T cells and thus are important for devising T-cell immunotherapies. In recent times, advances in mass spectrometry (MS) have enabled the precise identification of these MHC-I pept...

NetMHCpan 4.0: Improved peptide-MHC class I interaction predictions integrating eluted ligand and peptide binding affinity data

OpenAIRE

Jurtz, Vanessa; Paul, Sinu; Andreatta, Massimo; Marcatili, Paolo; Peters, Bjoern; Nielsen, Morten

2017-01-01

Cytotoxic T cells are of central importance in the immune systems response to disease. They recognize defective cells by binding to peptides presented on the cell surface by MHC (major histocompatibility complex) class I molecules. Peptide binding to MHC molecules is the single most selective step in the antigen presentation pathway. On the quest for T cell epitopes, the prediction of peptide binding to MHC molecules has therefore attracted large attention. In the past, predictors of peptide-...

Psychometric evaluation of the Mental Health Continuum-Short Form (MHC-SF) in Chinese adolescents - a methodological study.

Science.gov (United States)

Guo, Cheng; Tomson, Göran; Guo, Jizhi; Li, Xiangyun; Keller, Christina; Söderqvist, Fredrik

2015-12-10

In epidemiological surveillance of mental health there is good reason to also include scales that measure the presence of well-being rather than merely symptoms of ill health. The Mental Health Continuum-Short Form (MHC-SF) is a self-reported scale to measure emotional, psychological and social well-being and conduct categorical diagnosis of positive mental health. This particular instrument includes the three core components of the World Health Organization's definition of mental health and had previously not been psychometrically evaluated on adolescents in China. In total 5,399 students (51.1% female) from schools in the urban areas of Weifang in China were included in the study (mean age = 15.13, SD = 1.56). Participants completed a comprehensive questionnaire with several scales, among them the MHC-SF. Statistical analyses to evaluate reliability, structural validity, measurement invariance, presence of floor and ceiling effects and to some extent external validity of the MHC-SF were carried out. The Cronbach's α coefficients for sub-scales as well as the total scale were all above 0.80 indicating good reliability. Confirmative factor analysis confirmed the three-dimensional structure of the Chinese version of MHC-SF and supported the configural and metric invariance across gender and age. Noteworthy ceiling effects were observed for single items and sub-scales although not for the total scale. More importantly, observed floor effects were negligible. The stronger correlation found between MHC-SF and Minneapolis-Manchester Quality of Life Instrument (as measure of positive mental health) than between MHC-SF and Hospital Anxiety Depression Scale (as measure of mental illness and distress) yielded support for external validity. In conclusion, the main findings of this study are in line with studies from other countries that evaluated the psychometric properties of the MHC-SF and show that this instrument, that includes the three core components of the

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

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...... specificities and ligand length scales, and demonstrated how this approach significantly improves the accuracy for prediction of peptide binding and identification of MHC ligands. The method is available at www.cbs.dtu.dk/services/NetMHCpan-3.0....

Molecular characterization of classical and nonclassical MHC class I genes from the golden pheasant (Chrysolophus pictus).

Science.gov (United States)

Zeng, Q-Q; Zhong, G-H; He, K; Sun, D-D; Wan, Q-H

2016-02-01

Classical major histocompatibility complex (MHC) class I allelic polymorphism is essential for competent antigen presentation. To improve the genotyping efforts in the golden pheasant, it is necessary to differentiate more accurately between classical and nonclassical class I molecules. In our study, all MHC class I genes were isolated from one golden pheasant based on two overlapping PCR amplifications. In total, six full-length class I nucleotide sequences (A-F) were identified, and four were novel. Two (A and C) belonged to the IA1 gene, two (B and D) were alleles derived from the IA2 gene through transgene amplification, and two (E and F) comprised a third novel locus, IA3 that was excluded from the core region of the golden pheasant MHC-B. IA1 and IA2 exhibited the broad expression profiles characteristic of classical loci, while IA3 showed no expression in multiple tissues and was therefore defined as a nonclassical gene. Phylogenetic analysis indicated that the three IA genes in the golden pheasant share a much closer evolutionary relationship than the corresponding sequences in other galliform species. This observation was consistent with high sequence similarity among them, which likely arises from the homogenizing effect of recombination. Our careful distinction between the classical and nonclassical MHC class I genes in the golden pheasant lays the foundation for developing locus-specific genotyping and establishing a good molecular marker system of classical MHC I loci. © 2015 John Wiley & Sons Ltd.

Salmonella Typhimurium induces SPI-1 and SPI-2 regulated and strain dependent downregulation of MHC II expression on porcine alveolar macrophages

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Van Parys Alexander

2012-06-01

Full Text Available Abstract Foodborne salmonellosis is one of the most important bacterial zoonotic diseases worldwide. Salmonella Typhimurium is the serovar most frequently isolated from persistently infected slaughter pigs in Europe. Circumvention of the host’s immune system by Salmonella might contribute to persistent infection of pigs. In the present study, we found that Salmonella Typhimurium strain 112910a specifically downregulated MHC II, but not MHC I, expression on porcine alveolar macrophages in a Salmonella pathogenicity island (SPI-1 and SPI-2 dependent way. Salmonella induced downregulation of MHC II expression and intracellular proliferation of Salmonella in macrophages were significantly impaired after opsonization with Salmonella specific antibodies prior to inoculation. Furthermore, the capacity to downregulate MHC II expression on macrophages differed significantly among Salmonella strains, independently of strain specific differences in invasion capacity, Salmonella induced cytotoxicity and altered macrophage activation status. The fact that strain specific differences in MHC II downregulation did not correlate with the extent of in vitro SPI-1 or SPI-2 gene expression indicates that other factors are involved in MHC II downregulation as well. Since Salmonella strain dependent interference with the pig’s immune response through downregulation of MHC II expression might indicate that certain Salmonella strains are more likely to escape serological detection, our findings are of major interest for Salmonella monitoring programs primarily based on serology.

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

2009-12-01

Full Text Available 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.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.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.

S100A6 is a negative regulator of the induction of cardiac genes by trophic stimuli in cultured rat myocytes

International Nuclear Information System (INIS)

Tsoporis, J.N.; Marks, A.; Haddad, A.; O'Hanlon, D.; Jolly, S.; Parker, T.G.

2005-01-01

S100A6 (calcyclin), a member of the S100 family of EF-hand Ca 2+ binding proteins, has been implicated in the regulation of cell growth and proliferation. We have previously shown that S100B, another member of the S100 family, is induced postinfarction and limits the hypertrophic response of surviving cardiac myocytes. We presently report that S100A6 expression is also increased in the periinfarct zone of rat heart postinfarction and in cultured neonatal rat myocytes by treatment with several trophic agents, including platelet-derived growth factor (PDGF), the α 1 -adrenergic agonist phenylephrine (PE), and angiotensin II (AII). Cotransfection of S100A6 in cultured neonatal rat cardiac myocytes inhibits induction of the cardiac fetal gene promoters skeletal α-actin (skACT) and β-myosin heavy chain (β-MHC) by PDGF, PE, AII, and the prostaglandin F 2α (PGF 2α ), induction of the S100B promoter by PE, and induction of the α-MHC promoter by triiodothyronine (T3). By contrast, S100B cotransfection selectively inhibited only PE induction of skACT and β-MHC promoters. Fluorescence microscopy demonstrated overlapping intracellular distribution of S100B and S100A6 in transfected myocytes and in postinfarct myocardium but heterodimerization of the two proteins could not be detected by co-immunoprecipitation. We conclude that S100A6 may function as a global negative modulator of differentiated cardiac gene expression comparable to its putative role in cell cycle progression of dividing cells

Short-term effects of avian predation variation on population size and local survival of the multimammate rat, Mastomys natalensis (Rodentia, Muridae)

DEFF Research Database (Denmark)

Gulck, T. van; Stocks, R.; Verhagen, Ron

1998-01-01

The influence of avian predation on population size and local survival of Mastomys natalensis rats in Tanzania was studied in a capture-recapture study over a six month period on experimental fields with decreased, controlled and increased predation pressure. Bird observations indicated that the ......The influence of avian predation on population size and local survival of Mastomys natalensis rats in Tanzania was studied in a capture-recapture study over a six month period on experimental fields with decreased, controlled and increased predation pressure. Bird observations indicated...... that the placement of perches increased local hunting activity of at least the Black Shouldered Kite but there were no obvious effects on rodent population size or survival. In a single field where avian predation was prevented by covering the field with a net, an increase in survival was observed. The opposite...

The E5 protein of human papillomavirus type 16 perturbs MHC class II antigen maturation in human foreskin keratinocytes treated with interferon-γ

International Nuclear Information System (INIS)

Zhang Benyue; Li Ping; Wang Exing; Brahmi, Zacharie; Dunn, Kenneth W.; Blum, Janice S.; Roman, Ann

2003-01-01

Major histocompatibility complex (MHC) class II antigens are expressed on human foreskin keratinocytes (HFKs) following exposure to interferon gamma. The expression of MHC class II proteins on the cell surface may allow keratinocytes to function as antigen-presenting cells and induce a subsequent immune response to virus infection. Invariant chain (Ii) is a chaperone protein which plays an important role in the maturation of MHC class II molecules. The sequential degradation of Ii within acidic endocytic compartments is a key process required for the successful loading of antigenic peptide onto MHC class II molecules. Since human papillomavirus (HPV) 16 E5 can inhibit the acidification of late endosomes in HFKs, the E5 protein may be able to affect proper peptide loading onto the MHC class II molecule. To test this hypothesis, HFKs were infected with either control virus or a recombinant virus expressing HPV16 E5 and the infected cells were subsequently treated with interferon-γ. ELISAs revealed a decrease of MHC class II expression on the surface of E5-expressing cells compared with control virus-infected cells after interferon treatment. Western blot analysis showed that, in cells treated with interferon gamma, E5 could prevent the breakdown of Ii and block the formation of peptide-loaded, SDS-stable mature MHC class II dimers, correlating with diminished surface MHC class II expression. These data suggest that HPV16 E5 may be able to decrease immune recognition of infected keratinocytes via disruption of MHC class II protein function

MHC class I phenotype and function of human beta 2-microglobulin transgenic murine lymphocytes

DEFF Research Database (Denmark)

Bjerager, L; Pedersen, L O; Bregenholt, S

1996-01-01

. Based on data from cellular binding studies, Scatchard analyses and flow cytometry, it is concluded that exogenous h beta 2m does not bind to hybrid MHC class I (MHC-I) molecules composed of mouse heavy chain/h beta 2m molecules expressed on lymphocytes of transgenic mice. Immunoprecipitation and SDS......-PAGE analysis of metabolically labelled normal C57BL/6 lymph node cells showed binding of exogenous h beta 2m to MHC-I, in particular, to the H-2Db molecule through an exchange with endogenous mouse beta 2m. In contrast to normal H-2Db molecules, hybrid H-2Db expressed on the surface of transgenic lymphocytes...... binds radiolabelled peptide in the absence of exogenous added h beta 2m suggesting that a stable fraction of hybrid H-2Db molecules is empty or contain peptides with very low affinity. In a one-way allogenic mixed lymphocyte culture, transgenic splenocytes were found to be far less stimulatory than...

MHC-I modulation due to changes in tumor cell metabolism regulates tumor sensitivity to CTL and NK cells

Science.gov (United States)

Catalán, Elena; Charni, Seyma; Jaime, Paula; Aguiló, Juan Ignacio; Enríquez, José Antonio; Naval, Javier; Pardo, Julián; Villalba, Martín; Anel, Alberto

2015-01-01

Tumor cells have a tendency to use glucose fermentation to obtain energy instead of mitochondrial oxidative phosphorylation (OXPHOS). We demonstrated that this phenotype correlated with loss of ERK5 expression and with reduced MHC class I expression. Consequently, tumor cells could evade cytotoxic T lymphocyte (CTL)-mediated immune surveillance, but also increase their sensitivity to natural killer (NK) cells. These outcomes were evaluated using two cellular models: leukemic EL4 cells and L929 transformed fibroblasts and their derived ρ° cell lines, which lack mitochondrial DNA. We have also used a L929 cell sub-line that spontaneously lost matrix attachment (L929dt), reminiscent of metastasis generation, that also downregulated MHC-I and ERK5 expression. MHC-I expression is lower in ρ° cells than in the parental cell lines, but they were equally sensitive to CTL. On the contrary, ρ° cells were more sensitive to activated NK cells than parental cells. On the other hand, L929dt cells were resistant to CTL and NK cells, showed reduced viability when forced to perform OXPHOS, and surviving cells increased MHC-I expression and became sensitive to CTL. The present results suggest that when the reduction in MHC-I levels in tumor cells due to glycolytic metabolism is partial, the increase in sensitivity to NK cells seems to predominate. However, when tumor cells completely lose MHC-I expression, the combination of treatments that increase OXPHOS with CTL-mediated immunotherapy could be a promising therapeutic approach. PMID:25949869

MHC-I modulation due to changes in tumor cell metabolism regulates tumor sensitivity to CTL and NK cells.

Science.gov (United States)

Catalán, Elena; Charni, Seyma; Jaime, Paula; Aguiló, Juan Ignacio; Enríquez, José Antonio; Naval, Javier; Pardo, Julián; Villalba, Martín; Anel, Alberto

2015-01-01

Tumor cells have a tendency to use glucose fermentation to obtain energy instead of mitochondrial oxidative phosphorylation (OXPHOS). We demonstrated that this phenotype correlated with loss of ERK5 expression and with reduced MHC class I expression. Consequently, tumor cells could evade cytotoxic T lymphocyte (CTL)-mediated immune surveillance, but also increase their sensitivity to natural killer (NK) cells. These outcomes were evaluated using two cellular models: leukemic EL4 cells and L929 transformed fibroblasts and their derived ρ° cell lines, which lack mitochondrial DNA. We have also used a L929 cell sub-line that spontaneously lost matrix attachment (L929dt), reminiscent of metastasis generation, that also downregulated MHC-I and ERK5 expression. MHC-I expression is lower in ρ° cells than in the parental cell lines, but they were equally sensitive to CTL. On the contrary, ρ° cells were more sensitive to activated NK cells than parental cells. On the other hand, L929dt cells were resistant to CTL and NK cells, showed reduced viability when forced to perform OXPHOS, and surviving cells increased MHC-I expression and became sensitive to CTL. The present results suggest that when the reduction in MHC-I levels in tumor cells due to glycolytic metabolism is partial, the increase in sensitivity to NK cells seems to predominate. However, when tumor cells completely lose MHC-I expression, the combination of treatments that increase OXPHOS with CTL-mediated immunotherapy could be a promising therapeutic approach.

Association between the MHC gene region and variation of serum IgE levels against specific mould allergens in the horse

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Curik Ino

2003-06-01

Full Text Available Abstract To investigate whether the equine major histocompatibility complex (MHC gene region influences the production of mould-specific immunoglobulin E antibodies (IgE, alleles of the equine leukocyte antigen (ELA-A locus and three microsatellite markers (UM-011, HTG-05 and HMS-42 located on the same chromosome as the equine MHC were determined in 448 Lipizzan horses. Statistical analyses based on composite models, showed significant associations of the ELA-A and UM-011 loci with IgE titres against the recombinant Aspergillus fumigatus 7 antigen (rAsp f 7. UM-011 was also significantly associated with IgE titres against the recombinant Aspergillus fumigatus 8 antigen (rAsp f 8. In addition to the loci mentioned above, the MHC class II DQA and DRA loci were determined in 76 Lipizzans from one stud. For IgE levels against rAsp f 7, the composite model showed the strongest association for DQA (P rAsp f 8 specific IgE levels, similarly to the results found with all 448 horses, the strongest association was found with UM-011 (P = 0.01, which is closely linked with the MHC class II DRB locus. These results suggest that the equine MHC gene region and possibly MHC class II loci, influence the specific IgE response in the horse. However, although the strongest associations were found with DQA and UM-011, this study did not distinguish if the observed effects were due to the MHC itself or to other tightly linked genes.

A caspase-2-RFXANK interaction and its implication for MHC class II expression.

Science.gov (United States)

Forsberg, Jeremy; Li, Xinge; Akpinar, Birce; Salvatori, Roger; Ott, Martin; Zhivotovsky, Boris; Olsson, Magnus

2018-01-23

Despite recent achievements implicating caspase-2 in tumor suppression, the enzyme stands out from the apoptotic caspase family as a factor whose function requires further clarification. To specify enzyme characteristics through the definition of interacting proteins in apoptotic or non-apoptotic settings, a yeast 2-hybrid (Y2H) screen was performed using the full-length protein as bait. The current report describes the analysis of a captured prey and putative novel caspase-2 interacting factor, the regulatory factor X-associated ankyrin-containing protein (RFXANK), previously associated with CIITA, the transactivator regulating cell-type specificity and inducibility of MHC class II gene expression. The interaction between caspase-2 and RFXANK was verified by co-immunoprecipitations using both exogenous and endogenous proteins, where the latter approach suggested that binding of the components occurs in the cytoplasm. Cellular co-localization was confirmed by transfection of fluorescently conjugated proteins. Enhanced caspase-2 processing in RFXANK-overexpressing HEK293T cells treated with chemotherapeutic agents further supported Y2H data. Yet, no distinct differences with respect to MHC class II expression were observed in plasma membranes of antigen-presenting cells derived from wild type and caspase-2 -/- mice. In contrast, increased levels of the total MHC class II protein was evident in protein lysates from caspase-2 RNAi-silenced leukemia cell lines and B-cells isolated from gene-targeted mice. Together, these data identify a novel caspase-2-interacting factor, RFXANK, and indicate a potential non-apoptotic role for the enzyme in the control of MHC class II gene regulation.

Rat eosinophils stimulate the expansion of Cryptococcus neoformans-specific CD4+ and CD8+ T cells with a T-helper 1 profile

Science.gov (United States)

Garro, Ana P; Chiapello, Laura S; Baronetti, José L; Masih, Diana T

2011-01-01

Experimental Cryptococcus neoformans infection in rats has been shown to have similarities with human cryptococcosis, revealing a strong granulomatous response and a low susceptibility to dissemination. Moreover, it has been shown that eosinophils are components of the inflammatory response to C. neoformans infections. In this in vitro study, we demonstrated that rat peritoneal eosinophils phagocytose opsonized live yeasts of C. neoformans, and that the phenomenon involves the engagement of FcγRII and CD18. Moreover, our results showed that the phagocytosis of opsonized C. neoformans triggers eosinophil activation, as indicated by (i) the up-regulation of major histocompatibility complex (MHC) class I, MHC class II and costimulatory molecules, and (ii) an increase in interleukin (IL)-12, tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) production. However, nitric oxide (NO) and hydrogen peroxide (H2O2) synthesis by eosinophils was down-regulated after interaction with C. neoformans. Furthermore, this work demonstrated that CD4+ and CD8+ T lymphocytes isolated from spleens of infected rats and cultured with C. neoformans-pulsed eosinophils proliferate in an MHC class II- and class I-dependent manner, respectively, and produce important amounts of T-helper 1 (Th1) type cytokines, such as TNF-α and IFN-γ, in the absence of T-helper 2 (Th2) cytokine synthesis. In summary, the present study demonstrates that eosinophils act as fungal antigen-presenting cells and suggests that C. neoformans-loaded eosinophils might participate in the adaptive immune response. PMID:21039463

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

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...

Immunotherapy of MHC class I-deficient tumors

Czech Academy of Sciences Publication Activity Database

Reiniš, Milan

2010-01-01

Roč. 6, č. 10 (2010), s. 1577-1589 ISSN 1479-6694 R&D Projects: GA ČR GA301/07/1410; GA ČR GAP301/10/2174; GA AV ČR IAA500520807; GA AV ČR IAA500520605 EU Projects: European Commission(XE) 18933 - CLINIGENE Institutional research plan: CEZ:AV0Z50520514 Keywords : tumor vaccine * MHC class I expression * antigen presenting machinery Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.455, year: 2010

Inhibition of MHC-I by Brucella abortus is an early event during infection and involves EGFR pathway.

Science.gov (United States)

Velásquez, Lis N; Milillo, M Ayelén; Delpino, M Victoria; Trotta, Aldana; Mercogliano, M Florencia; Pozner, Roberto G; Schillaci, Roxana; Elizalde, Patricia V; Giambartolomei, Guillermo H; Barrionuevo, Paula

2017-04-01

Brucella abortus is able to persist inside the host despite the development of potent CD8 + T-cell responses. We have recently reported the ability of B. abortus to inhibit the interferon-γ-induced major histocompatibility complex (MHC)-I cell surface expression on human monocytes. This phenomenon was due to the B. abortus-mediated retention of MHC-I molecules within the Golgi apparatus and was dependent on bacterial viability. However, the implications of bacterial virulence or replicative capacity and the signaling pathways remained unknown. Here we demonstrated that the B. abortus mutant strains RB51 and virB10 - are able to inhibit MHC-I expression in the same manner as wild-type B. abortus, even though they are unable to persist inside human monocytes for a long period of time. Consistent with this, the phenomenon was triggered early in time and could be observed at 8 h postinfection. At 24 and 48 h, it was even stronger. Regarding the signaling pathway, targeting epidermal growth factor (EGF) receptor (EGFR), ErbB2 (HER2) or inhibition of tumor necrosis factor-α-converting enzyme, one of the enzymes which generates soluble EGF-like ligands, resulted in partial recovery of MHC-I surface expression. Moreover, recombinant EGF and transforming growth factor-α as well as the combination of both were also able to reproduce the B. abortus-induced MHC-I downmodulation. Finally, when infection was performed in the presence of an extracellular signal-regulated kinase 1/2 (Erk1/2) inhibitor, MHC-I surface expression was significantly recovered. Overall, these results describe how B. abortus evades CD8 + T-cell responses early during infection and exploits the EGFR-ERK signaling pathway to escape from the immune system and favor chronicity.

A community resource benchmarking predictions of peptide binding to MHC-I molecules.

Science.gov (United States)

Peters, Bjoern; Bui, Huynh-Hoa; Frankild, Sune; Nielson, Morten; Lundegaard, Claus; Kostem, Emrah; Basch, Derek; Lamberth, Kasper; Harndahl, Mikkel; Fleri, Ward; Wilson, Stephen S; Sidney, John; Lund, Ole; Buus, Soren; Sette, Alessandro

2006-06-09

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.

Characterization of a Nonclassical Class I MHC Gene in a Reptile, the Galápagos Marine Iguana (Amblyrhynchus cristatus)

Science.gov (United States)

Glaberman, Scott; Du Pasquier, Louis; Caccone, Adalgisa

2008-01-01

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. PMID:18682845

Characterization of a nonclassical class I MHC gene in a reptile, the Galápagos 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.

NetMHCpan-4.0: Improved Peptide-MHC Class I Interaction Predictions Integrating Eluted Ligand and Peptide Binding Affinity Data.

Science.gov (United States)

Jurtz, Vanessa; Paul, Sinu; Andreatta, Massimo; Marcatili, Paolo; Peters, Bjoern; Nielsen, Morten

2017-11-01

Cytotoxic T cells are of central importance in the immune system's response to disease. They recognize defective cells by binding to peptides presented on the cell surface by MHC class I molecules. Peptide binding to MHC molecules is the single most selective step in the Ag-presentation pathway. Therefore, in the quest for T cell epitopes, the prediction of peptide binding to MHC molecules has attracted widespread attention. In the past, predictors of peptide-MHC interactions have primarily been trained on binding affinity data. Recently, an increasing number of MHC-presented peptides identified by mass spectrometry have been reported containing information about peptide-processing steps in the presentation pathway and the length distribution of naturally presented peptides. In this article, we present NetMHCpan-4.0, a method trained on binding affinity and eluted ligand data leveraging the information from both data types. Large-scale benchmarking of the method demonstrates an increase in predictive performance compared with state-of-the-art methods when it comes to identification of naturally processed ligands, cancer neoantigens, and T cell epitopes. Copyright © 2017 by The American Association of Immunologists, Inc.

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

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...... mobilization of intracellular free calcium compared with MHC-I crosslinking of wild-type DT40 cells. Thus, expression of BCR at the cell surface is likely to be important for the signal cascade initiated by MHC-I crosslinking. Our data suggest that signal transduction initiated through ligation of the MHC...

The bioeconomics of controlling an African rodent pest species

DEFF Research Database (Denmark)

Skonhoft, Anders; Leirs, Herwig; Andreassen, Harry P

2006-01-01

The paper treats the economy of controlling an African pest rodent, the multimammate rat, causing major damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model...... incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the costs are made up of the cost of poison plus the damage to maize production. We analyse how the present-value costs of maize production are affected by various rodent control...

Species-specific evolution of class I MHC genes in iguanas (order: Squamata; subfamily: Iguaninae).

Science.gov (United States)

Glaberman, Scott; Caccone, Adalgisa

2008-07-01

Over the last few decades, the major histocompatibility complex (MHC) has emerged as a model for understanding the influence of natural selection on genetic diversity in populations as well as for investigating the genetic basis of host resistance to pathogens. However, many vertebrate taxa remain underrepresented in the field of MHC research, preventing its application to studies of disease, evolution, and conservation genetics in these groups. This is particularly true for squamates, which are by far the most diversified order of non-avian reptiles but have not been the subject of any recent MHC studies. In this paper, we present MHC class I complementary DNA data from three squamate species in the subfamily Iguaninae (iguanas): the Galápagos marine iguana (Amblyrhynchus cristatus), the Galápagos land iguana (Conolophus subcristatus), and the green iguana (Iguana iguana). All sequences obtained are related to the few published class I genes from other squamates. There is evidence for multiple loci in each species, and the conserved alpha-3 domain appears to be evolving in a species-specific manner. Conversely, there is some indication of shared polymorphism between species in the peptide-binding alpha-1 and alpha-2 domains, suggesting that these two regions have different phylogenetic histories. The great similarity between alpha-3 sequences in marine iguanas in particular suggests that concerted evolution is acting to homogenize class I loci within species. However, while less likely, the data are also compatible with a birth and death model of evolution.

Circumsporozoite Protein-Specific Kd-Restricted CD8+ T Cells Mediate Protective Antimalaria Immunity in Sporozoite-Immunized MHC-I-Kd Transgenic Mice

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Jing Huang

2014-01-01

Full Text Available Although the roles of CD8+ T cells and a major preerythrocytic antigen, the circumsporozoite (CS protein, in contributing protective antimalaria immunity induced by radiation-attenuated sporozoites, have been shown by a number of studies, the extent to which these players contribute to antimalaria immunity is still unknown. To address this question, we have generated C57BL/6 (B6 transgenic (Tg mice, expressing Kd molecules under the MHC-I promoter, called MHC-I-Kd-Tg mice. In this study, we first determined that a single immunizing dose of IrPySpz induced a significant level of antimalaria protective immunity in MHC-I-Kd-Tg mice but not in B6 mice. Then, by depleting various T-cell subsets in vivo, we determined that CD8+ T cells are the main mediator of the protective immunity induced by IrPySpz. Furthermore, when we immunized (MHC-I-Kd-Tg × CS-Tg F1 mice with IrPySpz after crossing MHC-I-Kd-Tg mice with PyCS-transgenic mice (CS-Tg, which are unable to mount PyCS-specific immunity, we found that IrPySpz immunization failed to induce protective antimalaria immunity in (MHC-I-Kd-Tg × CS-Tg F1 mice, thus indicating the absence of PyCS antigen-dependent immunity in these mice. These results indicate that protective antimalaria immunity induced by IrPySpz in MHC-I-Kd-Tg mice is mediated by CS protein-specific, Kd-restricted CD8+ T cells.

Selection on MHC class II supertypes in the New Zealand endemic Hochstetter's frog.

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Lillie, Mette; Grueber, Catherine E; Sutton, Jolene T; Howitt, Robyn; Bishop, Phillip J; Gleeson, Dianne; Belov, Katherine

2015-04-13

The New Zealand native frogs, family Leiopelmatidae, are among the most archaic in the world. Leiopelma hochstetteri (Hochstetter's frog) is a small, semi-aquatic frog with numerous, fragmented populations scattered across New Zealand's North Island. We characterized a major histocompatibility complex (MHC) class II B gene (DAB) in L. hochstetteri from a spleen transcriptome, and then compared its diversity to neutral microsatellite markers to assess the adaptive genetic diversity of five populations ("evolutionarily significant units", ESUs). L. hochstetteri possessed very high MHC diversity, with 74 DAB alleles characterized. Extremely high differentiation was observed at the DAB locus, with only two alleles shared between populations, a pattern that was not reflected in the microsatellites. Clustering analysis on putative peptide binding residues of the DAB alleles indicated four functional supertypes, all of which were represented in 4 of 5 populations, albeit at different frequencies. Otawa was an exception to these observations, with only two DAB alleles present. This study of MHC diversity highlights extreme population differentiation at this functional locus. Supertype differentiation was high among populations, suggesting spatial and/or temporal variation in selection pressures. Low DAB diversity in Otawa may limit this population's adaptive potential to future pathogenic challenges.

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.

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...... confirmed the original serological typing of the two recombinant B haplotypes. No recombination between B-F (class I) and B-L (class II) loci was found. This very low frequency of recombination within the B complex as compared with recombination frequencies found in mammalian MHC's is discussed...

Regulatory Lymphocytes Are Key Factors in MHC-Independent Resistance to EAE

Science.gov (United States)

Marín, Nieves; Mecha, Miriam; Espejo, Carmen; Mestre, Leyre; Eixarch, Herena; Montalban, Xavier; Álvarez-Cermeño, José C.; Guaza, Carmen; Villar, Luisa M.

2014-01-01

Background and Objectives. Resistant and susceptible mouse strains to experimental autoimmune encephalomyelitis (EAE), an inducible demyelinating experimental disease serving as animal model for multiple sclerosis, have been described. We aimed to explore MHC-independent mechanisms inducing resistance to EAE. Methods. For EAE induction, female C57BL/6 (susceptible strain) and CD1 (resistant outbred strain showing heterogeneous MHC antigens) mice were immunized with the 35–55 peptide of myelin oligodendrocyte glycoprotein (MOG35−55). We studied T cell proliferation, regulatory and effector cell subpopulations, intracellular and serum cytokine patterns, and titers of anti-MOG serum antibodies. Results. Upon immunization with MOG35−55, T lymphocytes from susceptible mice but not that of resistant strain were capable of proliferating when stimulated with MOG35−55. Accordingly, resistant mice experienced a rise in regulatory B cells (P = 0.001) and, to a lower extent, in regulatory T cells (P = 0.02) compared with C57BL/6 susceptible mice. As a consequence, MOG35−55-immunized C57BL/6 mice showed higher percentages of CD4+ T cells producing both IFN-gamma (P = 0.02) and IL-17 (P = 0.009) and higher serum levels of IL-17 (P = 0.04) than resistant mice. Conclusions. Expansion of regulatory B and T cells contributes to the induction of resistance to EAE by an MHC-independent mechanism. PMID:24868560

Regulatory Lymphocytes Are Key Factors in MHC-Independent Resistance to EAE

Directory of Open Access Journals (Sweden)

Nieves Marín

2014-01-01

Full Text Available Background and Objectives. Resistant and susceptible mouse strains to experimental autoimmune encephalomyelitis (EAE, an inducible demyelinating experimental disease serving as animal model for multiple sclerosis, have been described. We aimed to explore MHC-independent mechanisms inducing resistance to EAE. Methods. For EAE induction, female C57BL/6 (susceptible strain and CD1 (resistant outbred strain showing heterogeneous MHC antigens mice were immunized with the 35–55 peptide of myelin oligodendrocyte glycoprotein (MOG35−55. We studied T cell proliferation, regulatory and effector cell subpopulations, intracellular and serum cytokine patterns, and titers of anti-MOG serum antibodies. Results. Upon immunization with MOG35−55, T lymphocytes from susceptible mice but not that of resistant strain were capable of proliferating when stimulated with MOG35−55. Accordingly, resistant mice experienced a rise in regulatory B cells (P=0.001 and, to a lower extent, in regulatory T cells (P=0.02 compared with C57BL/6 susceptible mice. As a consequence, MOG35−55-immunized C57BL/6 mice showed higher percentages of CD4+ T cells producing both IFN-gamma (P=0.02 and IL-17 (P=0.009 and higher serum levels of IL-17 (P=0.04 than resistant mice. Conclusions. Expansion of regulatory B and T cells contributes to the induction of resistance to EAE by an MHC-independent mechanism.

Specific blockade by CD54 and MHC II of CD40-mediated signaling for B cell proliferation and survival

DEFF Research Database (Denmark)

Doyle, I S; Hollmann, C A; Crispe, I N

2001-01-01

Regulation of B lymphocyte proliferation is critical to maintenance of self-tolerance, and intercellular interactions are likely to signal such regulation. Here, we show that coligation of either the adhesion molecule ICAM-1/CD54 or MHC II with CD40 inhibited cell cycle progression and promoted...... these effects. Addition of BCR or IL-4 signals did not overcome the effect of ICAM-1 or MHC II on CD40-induced proliferation. FasL expression was not detected in B cell populations. These results show that MHC II and ICAM-1 specifically modulate CD40-mediated signaling, so inhibiting proliferation...

Brucella abortus down-regulates MHC class II by the IL-6-dependent inhibition of CIITA through the downmodulation of IFN regulatory factor-1 (IRF-1).

Science.gov (United States)

Velásquez, Lis N; Milillo, M Ayelén; Delpino, M Victoria; Trotta, Aldana; Fernández, Pablo; Pozner, Roberto G; Lang, Roland; Balboa, Luciana; Giambartolomei, Guillermo H; Barrionuevo, Paula

2017-03-01

Brucella abortus is an intracellular pathogen capable of surviving inside of macrophages. The success of B. abortus as a chronic pathogen relies on its ability to orchestrate different strategies to evade the adaptive CD4 + T cell responses that it elicits. Previously, we demonstrated that B. abortus inhibits the IFN-γ-induced surface expression of MHC class II (MHC-II) molecules on human monocytes, and this phenomenon correlated with a reduction in antigen presentation. However, the molecular mechanisms, whereby B. abortus is able to down-regulate the expression of MHC-II, remained to be elucidated. In this study, we demonstrated that B. abortus infection inhibits the IFN-γ-induced transcription of MHC-II, transactivator (CIITA) and MHC-II genes. Accordingly, we observed that the synthesis of MHC-II proteins was also diminished. B. abortus was not only able to reduce the expression of mature MHC-II, but it also inhibited the expression of invariant chain (Ii)-associated immature MHC-II molecules. Outer membrane protein 19 (Omp19), a prototypical B. abortus lipoprotein, diminished the expression of MHC-II and CIITA transcripts to the same extent as B. abortus infection. IL-6 contributes to these down-regulatory phenomena. In addition, B. abortus and its lipoproteins, through IL-6 secretion, induced the transcription of the negative regulators of IFN-γ signaling, suppressor of cytokine signaling (SOCS)-1 and -3, without interfering with STAT1 activation. Yet, B. abortus lipoproteins via IL-6 inhibit the expression of IFN regulatory factor 1 (IRF-1), a critical regulatory transcription factor for CIITA induction. Overall, these results indicate that B. abortus inhibits the expression of MHC-II molecules at very early points in their synthesis and in this way, may prevent recognition by T cells establishing a chronic infection. © Society for Leukocyte Biology.

CD4+ T cell-mediated cytotoxicity is associated with MHC class II expression on malignant CD19+ B cells in diffuse large B cell lymphoma.

Science.gov (United States)

Zhou, Yong; Zha, Jie; Lin, Zhijuan; Fang, Zhihong; Zeng, Hanyan; Zhao, Jintao; Luo, Yiming; Li, Zhifeng; Xu, Bing

2018-01-15

Diffuse large B cell lymphoma (DLBCL) is a common B cell malignancy with approximately 30% of patients present relapsed or refractory disease after first-line therapy. Research of further treatment options is needed. Cytotoxic CD4 + T cells express cytolytic molecules and have potential antitumor function. Here, we showed that the CD19 + cells from DLBCL patients presented significantly reduced expression of MHC II molecules than those from healthy controls. Three years after the first-line treatment, patients that presented relapsed disease had significantly lower MHC II expression on their CD19 + cells than patients who did not show recurrence. Examining cytotoxic CD4 + T cells show that DLBCL patients presented significantly elevated frequencies of granzyme A-, granzyme B-, and/or perforin-expressing cytotoxic CD4 + T cells. Also, frequency of cytotoxic CD4 + T cells in DLBCL patients was positively correlated with the MHC II expression level. Subsequently, the cytotoxic potential of CD4 + T cells against autologous CD19 + cells was investigated. We found that the cytotoxic potential of CD4 + T cells was highest in MHC II-high, intermediate in MHC II-mid, and lowest in MHC II-low patients. The percentage of MHC II-expressing viable CD19 + cells presented a significant reduction after longer incubation with cytotoxic CD4 + T cells, suggesting that cytotoxic CD4 + T cells preferentially eliminated MHC II-expressing CD19 + cells. Blocking MHC II on CD19 + cells significantly reduced the cytolytic capacity of CD4 + T cells. Despite these discoveries, the frequency of cytotoxic CD4 + T cells did not predict the clinical outcome of DLBCL patients. Together, these results demonstrated that cytotoxic CD4 + T cells presented an MHC II-dependent cytotoxic potential against autologous CD19 + cells and could potentially represent a future treatment option for DLBCL. Copyright © 2017 Elsevier Inc. All rights reserved.

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

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.

Population genetic segmentation of MHC-correlated perfume preferences.

Science.gov (United States)

Hämmerli, A; Schweisgut, C; Kaegi, M

2012-04-01

It has become difficult to find a matching perfume. An overwhelming number of 300 new perfumes launch each year, and marketing campaigns target pre-defined groups based on gender, age or income rather than on individual preferences. Recent evidence for a genetic basis of perfume preferences, however, could be the starting point for a novel population genetic approach to better match perfumes with people's preferences. With a total of 116 participants genotyped for alleles of three loci of the major histocompatibility complex (MHC), the aim of this study was to test whether common MHC alleles could be used as genetic markers to segment a given population into preference types. Significant deviations from random expectations for a set of 10 common perfume ingredients indicate how such segmentation could be achieved. In addition, preference patterns of participants confronted with images that contained a sexual communication context significantly differed in their ratings for some of the scents compared with participants confronted with images of perfume bottles. This strongly supports the assumption that genetically correlated perfume preferences evolved in the context of sexual communication. The results are discussed in the light of perfume customization. © 2011 The Authors. ICS © 2011 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

X-ray crystallographic characterization of rhesus macaque MHC Mamu-A*02 complexed with an immunodominant SIV-Gag nonapeptide

International Nuclear Information System (INIS)

Feng, Youjun; Qi, Jianxun; Zhang, Huimin; Wang, Jinzi; Liu, Jinhua; Jiang, Fan; Gao, Feng

2005-01-01

X-ray crystallographic characterization of rhesus macaque MHC Mamu-A*02 complexed with an immunodominant SIV-Gag nonapeptide. Simian immunodeficiency virus (SIV) in the rhesus macaque is regarded as a classic animal model, playing a crucial role in HIV vaccine strategies and therapeutics by characterizing various cytotoxic T-lymphocyte (CTL) responses in macaque monkeys. However, the availability of well documented structural reports focusing on rhesus macaque major histocompatibility complex class I (MHC I) molecules remains extremely limited. Here, a complex of the rhesus macaque MHC I molecule (Mamu-A*02) with human β 2 m and an immunodominant SIV-Gag nonapeptide, GESNLKSLY (GY9), has been crystallized. The crystal diffracts X-rays to 2.7 Å resolution and belongs to space group C2, with unit-cell parameters a = 124.11, b = 110.45, c = 100.06 Å, and contains two molecules in the asymmetric unit. The availability of the structure, which is being solved by molecular replacement, will provide new insights into rhesus macaque MHC I (Mamu-A*02) presenting pathogenic SIV peptides

X-ray crystallographic characterization of rhesus macaque MHC Mamu-A*02 complexed with an immunodominant SIV-Gag nonapeptide

Energy Technology Data Exchange (ETDEWEB)

Feng, Youjun [Laboratory of Molecular Immunology and Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China); Graduate School, Chinese Academy of Sciences, Beijing (China); Qi, Jianxun [Graduate School, Chinese Academy of Sciences, Beijing (China); Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Zhang, Huimin; Wang, Jinzi [Laboratory of Molecular Immunology and Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China); Liu, Jinhua [College of Veterinary Medicine, China Agricultural University, Beijing 100094 (China); Jiang, Fan [Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Gao, Feng, E-mail: gaofeng@im.ac.cn [Laboratory of Molecular Immunology and Molecular Virology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080 (China); College of Veterinary Medicine, China Agricultural University, Beijing 100094 (China)

2006-01-01

X-ray crystallographic characterization of rhesus macaque MHC Mamu-A*02 complexed with an immunodominant SIV-Gag nonapeptide. Simian immunodeficiency virus (SIV) in the rhesus macaque is regarded as a classic animal model, playing a crucial role in HIV vaccine strategies and therapeutics by characterizing various cytotoxic T-lymphocyte (CTL) responses in macaque monkeys. However, the availability of well documented structural reports focusing on rhesus macaque major histocompatibility complex class I (MHC I) molecules remains extremely limited. Here, a complex of the rhesus macaque MHC I molecule (Mamu-A*02) with human β{sub 2}m and an immunodominant SIV-Gag nonapeptide, GESNLKSLY (GY9), has been crystallized. The crystal diffracts X-rays to 2.7 Å resolution and belongs to space group C2, with unit-cell parameters a = 124.11, b = 110.45, c = 100.06 Å, and contains two molecules in the asymmetric unit. The availability of the structure, which is being solved by molecular replacement, will provide new insights into rhesus macaque MHC I (Mamu-A*02) presenting pathogenic SIV peptides.

Reversible epigenetic down-regulation of MHC molecules by devil facial tumour disease illustrates immune escape by a contagious cancer

DEFF Research Database (Denmark)

Siddle, Hannah V; Kreiss, Alexandre; Tovar, Cesar

2013-01-01

Contagious cancers that pass between individuals as an infectious cell line are highly unusual pathogens. Devil facial tumor disease (DFTD) is one such contagious cancer that emerged 16 y ago and is driving the Tasmanian devil to extinction. As both a pathogen and an allograft, DFTD cells should...... be rejected by the host-immune response, yet DFTD causes 100% mortality among infected devils with no apparent rejection of tumor cells. Why DFTD cells are not rejected has been a question of considerable confusion. Here, we show that DFTD cells do not express cell surface MHC molecules in vitro or in vivo......, MHC class I molecules can be restored to the surface of DFTD cells in vitro by using recombinant devil IFN-γ, which is associated with up-regulation of the MHC class II transactivator, a key transcription factor with deacetylase activity. Further, expression of MHC class I molecules by DFTD cells can...

Bacterial superantigens promote acute nasopharyngeal infection by Streptococcus pyogenes in a human MHC Class II-dependent manner.

Directory of Open Access Journals (Sweden)

Katherine J Kasper

2014-05-01

Full Text Available 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.

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...

A Novel Therapeutic Vaccine for Metastatic Mammary Carcinoma: Focusing MHC/Peptide Complexes to Lipid Rafts

Science.gov (United States)

2006-11-01

reportable outcomes). Briefly, the T cell lymphoma EL4 and the immortalized fibroblast cell line DAP (both expressing ova) were used to measure...and Use Committee. Cells , transfections, and antibodies B16.BL6 8.2, A20, EL4 and EL4 /ova were cultured as described (20-22). NIH3T3 cells were...types can donate MHC class I molecules to DC. To determine if the levels of MHC class I on the donor cell affected the efficiency of transfer, EL4 /ova

Immunization with MHC class I-negative but not -positive HPV16-associated tumour cells inhibits growth of MHC class I-negative tumours

Czech Academy of Sciences Publication Activity Database

Reiniš, Milan; Šímová, Jana; Indrová, Marie; Bieblová, Jana; Přibylová, Hana; Moravcová, Simona; Jandlová, Táňa; Bubeník, Jan

2007-01-01

Roč. 30, č. 4 (2007), s. 1011-1017 ISSN 1019-6439 R&D Projects: GA MZd NR7807 EU Projects: European Commission(XE) 18933 - CLINIGENE Grant - others:Liga proti rakovině, Praha(CZ) XX Institutional research plan: CEZ:AV0Z50520514 Keywords : HPV16 * MHC class I-deficient tumours * immunologic crossreaction Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.295, year: 2007

Ligation of major histocompatibility complex class I antigens (MHC-I) prevents apoptosis induced by Fas or SAPK/JNK activation in T-lymphoma cells

DEFF Research Database (Denmark)

Lamberth, K; Claesson, M H

2001-01-01

Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti-apoptotic......Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti......-apoptotic Bcl-2 protein and stabilized the mitochondrial membrane potential (Deltapsim). MHC-I ligation also prevented downregulation of Bcl-2 and destabilization of Deltapsim induced by anti-Fas Ab treatment or anisomycin exposure. Studies on three different Jurkat cell mutants deficient for src p56(lck), ZAP......-70 kinase, or TCR/CD3 gamma-chain showed that the cells undergo apoptosis after Fas ligation. Anisomycin exposure induced apoptosis in the src p56(lck)-deficient cell line but not in the two other mutant cell lines. Simultaneous cross-linking of MHC-I and Fas ligation inhibited apoptosis in the ZAP...

Repression of MHC class I transcription by HPV16E7 through interaction with a putative RXRβ motif and NF-κB cytoplasmic sequestration

International Nuclear Information System (INIS)

Li, Hui; Zhan, TaiLan; Li, Chang; Liu, Mugen; Wang, Qing K.

2009-01-01

Down-regulation of transcription of the MHC class I genes in HPV16 tumorigenic cells is partly due to HPV16E7 associated with the MHC class I promoter and repressed chromatin activation. In this study, we further demonstrated that HPV16E7 is physically associated with a putative RXRβ binding motif (GGTCA) of the proximal promoter of the MHC class I genes by using reporter transcriptional assays and chromatin immunoprecipitation assays. Our data also provide evidence that HPV16E7 inhibits TNF-α-induced up-regulation of MHC class I transcription by impaired nuclear translocation of NF-κB. More importantly, CaSki tumor cells treated with TSA and transfected with the constitutively active mutant form of IKK-α (which can activate NF-κB directly) showed a maximal level of up-regulation of MHC-I expression. Taken together, our results suggest that HPV16E7 may employ two independent mechanisms to ensure that either the constitutive or inducible transcription of MHC class I genes is down-regulated.

Haplotype specific alteration of diabetes MHC risk by olfactory receptor gene polymorphism.

Science.gov (United States)

Jahromi, Mohamed M

2012-12-01

Evidence for genes associated with risk for Type 1 diabetes (T1D) in the extended region of the major histocompatibility complex (MHC) genes is accumulating. The aim of this study was to investigate the association pattern of the extended MHC region with T1D susceptibility to identify effects independent of well established DR/DQ genes. A total of 394 Europid families with T1D were genotyped for the single nucleotide polymorphism (SNP) in the olfactory receptor family 14, subfamily J, member 1 (OR14J1) gene, rs9257691, in the MHC telomeric region. The OR provides "an internal depiction of our external world" through the capture of odorant molecules in the main OR system by several large families of G-protein coupled receptors (GPCR). These receptors transduce and chemosignals into the central nervous system (CNS). This SNP was chosen to identify its association with T1D. Interestingly, OR14J1C allele was significantly associated with T1D that seems to go with DRB1*0401, Χ(2)=10.9, p=0.0003. However, by fixing both genes of DR*0401-DQB1*0302, high risk, the association of T1D with OR14J1C still existed, Χ(2)=7.4, p=0.005. The occurrence of association of the OR14J1C allele with T1D patients with DRB1*401/DQB1*0302 is an independent risk for T1D. As an accumulative report suggests the role of OR in the pathogenesis of diabetic microvascular and other diabetic complications, undoubtedly, this haplotype specific alteration of T1D risk is an independent risk for the disease and can address the promising MHC-linked gene other than DR/DQ. Moreover, there is nothing to hinder for that this might be a signal that identifies the role of OR gene in the pathogenesis of T1D in patients who are prone to diabetic complications. Copyright © 2012. Published by Elsevier B.V.

Effects of chronic Akt/mTOR inhibition by rapamycin on mechanical overload-induced hypertrophy and myosin heavy chain transition in masseter muscle.

Science.gov (United States)

Umeki, Daisuke; Ohnuki, Yoshiki; Mototani, Yasumasa; Shiozawa, Kouichi; Fujita, Takayuki; Nakamura, Yoshiki; Saeki, Yasutake; Okumura, Satoshi

2013-01-01

To examine the effects of the Akt/mammalian target of rapamycin (mTOR) pathway on masseter muscle hypertrophy and myosin heavy chain (MHC) transition in response to mechanical overload, we analyzed the effects of bite-opening (BO) on the hypertrophy and MHC composition of masseter muscle of BO-rats treated or not treated with rapamycin (RAPA), a selective mTOR inhibitor. The masseter muscle weight in BO-rats was significantly greater than that in controls, and this increase was attenuated by RAPA treatment. Expression of slow-twitch MHC isoforms was significantly increased in BO-rats with/without RAPA treatment, compared with controls, but the magnitude of the increase was much smaller in RAPA-treated BO-rats. Phosphorylation of p44/42 MAPK (ERK1/2), which preserves fast-twitch MHC isoforms in skeletal muscle, was significantly decreased in BO-rats, but the decrease was abrogated by RAPA treatment. Calcineurin signaling is known to be important for masseter muscle hypertrophy and fast-to-slow MHC isoform transition, but expression of known calcineurin activity modulators was unaffected by RAPA treatment. Taken together, these results indicate that the Akt/mTOR pathway is involved in both development of masseter muscle hypertrophy and fast-to-slow MHC isoform transition in response to mechanical overload with inhibition of the ERK1/2 pathway and operates independently of the calcineurin pathway.

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

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...... 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...

The function of androgen/androgen receptor and insulin growth factor‑1/insulin growth factor‑1 receptor on the effects of Tribulus terrestris extracts in rats undergoing high intensity exercise.

Science.gov (United States)

Wu, Yin; Yang, Hongfang; Wang, Xiaohui

2017-09-01

Our previous study demonstrated that treatment with Tribulus terrestris (TT) extracts (120 mg/kg) promoted the muscle weight gain and performance of rats undergoing high intensity exercise. The present study was designed to explore the mechanisms underlying the effect of treatment with TT extracts and the involvement of androgens, the androgen receptor (AR), insulin growth factor‑1 (IGF‑1) and the IGF‑1 receptor (IGF‑1R). A total of 32 Sprague‑Dawley rats were randomly divided into groups as follows: Control; TT, treated with TT extracts, E, high intensity exercise; E+TT, high intensity exercise plus TT treatment. The rats of the E and E+TT groups underwent high intensity exercise with a progressively increasing load for 5 weeks, and TT extracts were intragastrically administered in the TT and E+TT rats 30 min prior to training. TT extract composition was analyzed using ultra‑high performance liquid chromatography‑quadrupole‑time of flight mass spectrometry. Testosterone and IGF‑1 plasma levels and AR, IGF‑1R and myosin heavy chain (MHC) protein levels in muscles were determined by ELISA and western blotting, respectively. The saponins tigogenin and diosgenin comprised ~71.35% of the total peak area. Compared with the E group, TT extracts increased the testosterone and IGF‑1 plasma levels, and AR, IGF‑1R and MHC protein levels in the gastrocnemius of rats undergoing high intensity exercise, accompanied with increased body weight and gastrocnemius weight. In conclusion, the effect of TT extracts on the performance of high intensity exercise rats may be attributed to increased levels of circulating testosterone and IGF‑1 and increased AR and IGF‑1R protein expression levels in the gastrocnemius, resulting in increased muscle weight and increased MHC in the gastrocnemius. The present study provided preliminary evidence supporting the use of TT extracts as a dietary supplement for the promotion of skeletal muscle mass increase and the

Parasites and parallel divergence of the number of individual MHC alleles between sympatric three-spined stickleback Gasterosteus aculeatus morphs in Iceland.

Science.gov (United States)

Natsopoulou, M E; Pálsson, S; Ólafsdóttir, G Á

2012-10-01

Two pairs of sympatric three-spined stickleback Gasterosteus aculeatus morphs and two single morph populations inhabiting mud and lava or rocky benthic habitats in four Icelandic lakes were screened for parasites and genotyped for MHC class IIB diversity. Parasitic infection differed consistently between G. aculeatus from different benthic habitats. Gasterosteus aculeatus from the lava or rocky habitats were more heavily infected in all lakes. A parallel pattern was also found in individual MHC allelic variation with lava G. aculeatus morphs exhibiting lower levels of variation than the mud morphs. Evidence for selective divergence in MHC allele number is ambiguous but supported by two findings in addition to the parallel pattern observed. MHC allele diversity was not consistent with diversity reported at neutral markers (microsatellites) and in Þingvallavatn the most common number of alleles in each morph was associated with lower infection levels. In the Þingvallavatn lava morph, lower infection levels by the two most common parasites, Schistocephalus solidus and Diplostomum baeri, were associated with different MHC allele numbers. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

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

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

The MHC locus and genetic susceptibility to autoimmune and infectious diseases

NARCIS (Netherlands)

Matzaraki, Vasiliki; Kumar, Vinod; Wijmenga, Cisca; Zhernakova, Alexandra

2017-01-01

In the past 50 years, variants in the major histocompatibility complex (MHC) locus, also known as the human leukocyte antigen (HLA), have been reported as major risk factors for complex diseases. Recent advances, including large genetic screens, imputation, and analyses of non-additive and epistatic

Mass Spectrometry Reveals Changes in MHC I Antigen Presentation After Lentivector Expression of a Gene Regulation System

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Roland Vogel

2013-01-01

Full Text Available The rapamycin-inducible gene regulation system was designed to minimize immune reactions in man and may thus be suited for gene therapy. We assessed whether this system indeed induces no immune responses. The protein components of the regulation system were produced in the human cell lines HEK 293T, D407, and HER 911 following lentiviral transfer of the corresponding genes. Stable cell lines were established, and the peptides presented by major histocompatibility complex class I (MHC I molecules on transduced and wild-type (wt cells were compared by differential mass spectrometry. In all cell lines examined, expression of the transgenes resulted in prominent changes in the repertoire of MHC I-presented self-peptides. No MHC I ligands originating from the transgenic proteins were detected. In vitro analysis of immunogenicity revealed that transduced D407 cells displayed slightly higher capacity than wt controls to promote proliferation of cytotoxic T cells. These results indicate that therapeutic manipulations within the genome of target cells may affect pathways involved in the processing of peptide antigens and their presentation by MHC I. This makes the genomic modifications visible to the immune system which may recognize these events and respond. Ultimately, the findings call attention to a possible immune risk.

B. abortus RNA is the component involved in the down-modulation of MHC-I expression on human monocytes via TLR8 and the EGFR pathway

Science.gov (United States)

Milillo, M. Ayelén; Velásquez, Lis N.; Trotta, Aldana; Delpino, M. Victoria; Balboa, Luciana; Vermeulen, Mónica; Espindola, Sonia L.; Rodriguez-Rodrigues, Nahuel; Fernández, Gabriela C.; Oliveira, Sergio Costa; Giambartolomei, Guillermo H.

2017-01-01

Despite eliciting a potent CD8+ T cell response, Brucella abortus is able to persist and establish a chronic infection inside its host. We have previously reported that the infection of human monocytes/macrophages with B. abortus inhibits the IFN-γ-induced MHC-I cell surface expression down-modulating cytotoxic CD8+ T cell responses. MHC-I down-modulation depends on bacterial viability and results from the capacity of B. abortus to retain the MHC-I molecules within the Golgi apparatus. Furthermore, we recently demonstrated that epidermal growth factor receptor (EGFR) pathway is involved in this phenomenon and that this is an early event during infection. However, the components and mechanisms whereby B. abortus is able to down-modulate MHC-I remained to be elucidated. In this study we demonstrated that the down-modulation of MHC-I expression is not mediated by well-known Brucella virulence factors but instead by B. abortus RNA, a PAMP associated to viability (vita-PAMP). Surprisingly, completely degraded RNA was also able to inhibit MHC-I expression to the same extent as intact RNA. Accordingly, B. abortus RNA and its degradation products were able to mimic the MHC-I intracellular retention within the Golgi apparatus observed upon infection. We further demonstrated that TLR8, a single-stranded RNA and RNA degradation products sensor, was involved in MHC-I inhibition. On the other hand, neutralization of the EGFR reversed the MHC-I inhibition, suggesting a connection between the TLR8 and EGFR pathways. Finally, B. abortus RNA-treated macrophages display diminished capacity of antigen presentation to CD8+ T cells. Overall, our results indicate that the vita-PAMP RNA as well as its degradation products constitute novel virulence factors whereby B. abortus, by a TLR8-dependent mechanism and through the EGFR pathway, inhibits the IFN-γ-induced MHC-I surface expression on human monocytes/macrophages. Thus, bacteria can hide within infected cells and avoid the

B. abortus RNA is the component involved in the down-modulation of MHC-I expression on human monocytes via TLR8 and the EGFR pathway.

Directory of Open Access Journals (Sweden)

M Ayelén Milillo

2017-08-01

Full Text Available Despite eliciting a potent CD8+ T cell response, Brucella abortus is able to persist and establish a chronic infection inside its host. We have previously reported that the infection of human monocytes/macrophages with B. abortus inhibits the IFN-γ-induced MHC-I cell surface expression down-modulating cytotoxic CD8+ T cell responses. MHC-I down-modulation depends on bacterial viability and results from the capacity of B. abortus to retain the MHC-I molecules within the Golgi apparatus. Furthermore, we recently demonstrated that epidermal growth factor receptor (EGFR pathway is involved in this phenomenon and that this is an early event during infection. However, the components and mechanisms whereby B. abortus is able to down-modulate MHC-I remained to be elucidated. In this study we demonstrated that the down-modulation of MHC-I expression is not mediated by well-known Brucella virulence factors but instead by B. abortus RNA, a PAMP associated to viability (vita-PAMP. Surprisingly, completely degraded RNA was also able to inhibit MHC-I expression to the same extent as intact RNA. Accordingly, B. abortus RNA and its degradation products were able to mimic the MHC-I intracellular retention within the Golgi apparatus observed upon infection. We further demonstrated that TLR8, a single-stranded RNA and RNA degradation products sensor, was involved in MHC-I inhibition. On the other hand, neutralization of the EGFR reversed the MHC-I inhibition, suggesting a connection between the TLR8 and EGFR pathways. Finally, B. abortus RNA-treated macrophages display diminished capacity of antigen presentation to CD8+ T cells. Overall, our results indicate that the vita-PAMP RNA as well as its degradation products constitute novel virulence factors whereby B. abortus, by a TLR8-dependent mechanism and through the EGFR pathway, inhibits the IFN-γ-induced MHC-I surface expression on human monocytes/macrophages. Thus, bacteria can hide within infected cells and

Barrett associated MHC and FOXF1 variants also increase esophageal carcinoma risk

NARCIS (Netherlands)

Dura, P.; Veen, E.M. van; Salomon, J.; Morsche, R.H.M. te; Roelofs, H.M.J.; Kristinsson, J.O.; Wobbes, T.; Witteman, B.J.; Tan, A.C.; Drenth, J.P.H.; Peters, W.H.M.

2013-01-01

Barrett's esophagus, with gastroesophageal reflux disease and obesity as risk factors, predisposes to esophageal adenocarcinoma (EAC). Recently a British genome wide association study identified two Barrett's esophagus susceptibility loci mapping within the major histocompatibility complex (MHC;

Quantum chemical analysis explains hemagglutinin peptide-MHC Class II molecule HLA-DRβ1*0101 interactions

International Nuclear Information System (INIS)

Cardenas, Constanza; Villaveces, Jose Luis; Bohorquez, Hugo; Llanos, Eugenio; Suarez, Carlos; Obregon, Mateo; Patarroyo, Manuel Elkin

2004-01-01

We present a new method to explore interactions between peptides and major histocompatibility complex (MHC) molecules using the resultant vector of the three principal multipole terms of the electrostatic field expansion. Being that molecular interactions are driven by electrostatic interactions, we applied quantum chemistry methods to better understand variations in the electrostatic field of the MHC Class II HLA-DRβ1*0101-HA complex. Multipole terms were studied, finding strong alterations of the field in Pocket 1 of this MHC molecule, and weak variations in other pockets, with Pocket 1 >> Pocket 4 > Pocket 9 ∼ Pocket 7 > Pocket 6. Variations produced by 'ideal' amino acids and by other occupying amino acids were compared. Two types of interactions were found in all pockets: a strong unspecific one (global interaction) and a weak specific interaction (differential interaction). Interactions in Pocket 1, the dominant pocket for this allele, are driven mainly by the quadrupole term, confirming the idea that aromatic rings are important in these interactions. Multipolar analysis is in agreement with experimental results, suggesting quantum chemistry methods as an adequate methodology to understand these interactions

Down-regulation of MHC class I by the Marek's disease virus (MDV) UL49.5 gene product mildly affects virulence in a haplotype-specific fashion.

Science.gov (United States)

Jarosinski, Keith W; Hunt, Henry D; Osterrieder, Nikolaus

2010-09-30

Marek's disease is a devastating neoplastic disease of chickens caused by Marek's disease virus (MDV). MDV down-regulates surface expression of MHC class I molecules, although the mechanism has remained elusive. MDV harbors a UL49.5 homolog that has been shown to down-regulate MHC class I expression in other Varicelloviruses. Using in vitro assays, we showed that MDV pUL49.5 down-regulates MHC class I directly and identified its cytoplasmic tail as essential for this function. In vivo, viruses lacking the cytoplasmic tail of pUL49.5 showed no differences in MD pathogenesis compared to revertant viruses in highly susceptible chickens of the B(19)B(19) MHC class I haplotype, while there was a mild reduction in pathogenic potential of the deletion viruses in chickens more resistant to MD pathogenesis (MHC:B(21)B(21)). We concluded that the pathogenic effect of MHC class I down-regulation mediated by pUL49.5 is small because virus immune evasion possibly requires more than one viral protein. Copyright 2010 Elsevier Inc. All rights reserved.

Gαq protein carboxyl terminus imitation polypeptide GCIP-27 improves cardiac function in chronic heart failure rats.

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Xiao Lan Lu

Full Text Available Gαq protein carboxyl terminus imitation polypeptide (GCIP-27 has been shown to alleviate pathological cardiomyocyte hypertrophy induced by various factors. Pathological cardiac hypertrophy increases the morbidity and mortality of cardiovascular diseases while it compensates for poor heart function. This study was designed to investigate the effects of GCIP-27 on heart function in rats with heart failure induced by doxorubicin.Forty-eight rats were randomly divided into the following six groups receiving vehicle (control, doxorubicin (Dox, losartan (6 mg/kg, i.g. and three doses of GCIP-27 (10, 30, 90 μg/kg; i.p., bid, respectively. Heart failure was induced by Dox, which was administered at a 20 mg/kg cumulative dose. After 10 weeks of treatment, we observed that GCIP-27 (30, 90 μg/kg significantly increased ejection fraction, fraction shortening, stroke volume and sarcoplasmic reticulum Ca2+ ATPase activity of Dox-treated hearts. Additionally, GCIP-27 decreased myocardial injury, heart weight index and left ventricular weight index, fibrosis and serum cardiac troponin-I concentration in Dox-treated mice. Immunohistochemistry, western blotting and real-time PCR experiments indicated that GCIP-27 (10-90 μg/kg could markedly upregulate the protein expression of myocardial α-myosin heavy chain (MHC, Bcl-2, protein kinase C (PKC ε and phosphorylated extracellular signal-regulated kinase (p-ERK 1/2 as well as the mRNA expression of α-MHC, but downregulated the expression of β-MHC, Bax and PKC βII, and the mRNA expression levels of β-MHC in Dox-treated mice. It was also found that GCIP-27 (30, 90 μg/L decreased cell size and protein content of cardiomyocytes significantly in vitro by comparison of Dox group.GCIP-27 could effectively ameliorate heart failure development induced by Dox. PKC-ERK1/2 signaling might represent the underlying mechanism of the beneficial effects of GCIP-27.

Distribution of CD163-positive cell and MHC class II-positive cell in the normal equine uveal tract.

Science.gov (United States)

Sano, Yuto; Matsuda, Kazuya; Okamoto, Minoru; Takehana, Kazushige; Hirayama, Kazuko; Taniyama, Hiroyuki

2016-02-01

Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immune homeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder, little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated the distribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using an immunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used. Indirect immunofluorescence was performed using the primary antibodies CD163, MHC class II (MHC II) and CD20. To demonstrate the site of their greatest distribution, positive cells were manually counted in 3 different parts of the uveal tract (ciliary body, iris and choroid), and their average number was assessed by statistical analysis. The distribution of pleomorphic CD163- and MHC II-expressed cells was detected throughout the equine uveal tract, but no CD20-expressed cells were detected. The statistical analysis demonstrated the distribution of CD163- and MHC II-positive cells focusing on the ciliary body. These results demonstrated that the ciliary body is the largest site of their distribution in the normal equine uveal tract, and the ciliary body is considered to play important roles in uveal and/or ocular immune homeostasis. The data provided in this study will help further understanding of equine ocular immunity in the normal state and might be beneficial for understanding of mechanisms of ocular disorders, such as equine uveitis.

Patterns of genetic differentiation at MHC class I genes and microsatellites identify conservation units in the giant panda.

Science.gov (United States)

Zhu, Ying; Wan, Qiu-Hong; Yu, Bin; Ge, Yun-Fa; Fang, Sheng-Guo

2013-10-22

Evaluating patterns of genetic variation is important to identify conservation units (i.e., evolutionarily significant units [ESUs], management units [MUs], and adaptive units [AUs]) in endangered species. While neutral markers could be used to infer population history, their application in the estimation of adaptive variation is limited. The capacity to adapt to various environments is vital for the long-term survival of endangered species. Hence, analysis of adaptive loci, such as the major histocompatibility complex (MHC) genes, is critical for conservation genetics studies. Here, we investigated 4 classical MHC class I genes (Aime-C, Aime-F, Aime-I, and Aime-L) and 8 microsatellites to infer patterns of genetic variation in the giant panda (Ailuropoda melanoleuca) and to further define conservation units. Overall, we identified 24 haplotypes (9 for Aime-C, 1 for Aime-F, 7 for Aime-I, and 7 for Aime-L) from 218 individuals obtained from 6 populations of giant panda. We found that the Xiaoxiangling population had the highest genetic variation at microsatellites among the 6 giant panda populations and higher genetic variation at Aime-MHC class I genes than other larger populations (Qinling, Qionglai, and Minshan populations). Differentiation index (FST)-based phylogenetic and Bayesian clustering analyses for Aime-MHC-I and microsatellite loci both supported that most populations were highly differentiated. The Qinling population was the most genetically differentiated. The giant panda showed a relatively higher level of genetic diversity at MHC class I genes compared with endangered felids. Using all of the loci, we found that the 6 giant panda populations fell into 2 ESUs: Qinling and non-Qinling populations. We defined 3 MUs based on microsatellites: Qinling, Minshan-Qionglai, and Daxiangling-Xiaoxiangling-Liangshan. We also recommended 3 possible AUs based on MHC loci: Qinling, Minshan-Qionglai, and Daxiangling-Xiaoxiangling-Liangshan. Furthermore, we recommend

MHC class IIB Exon 2 Polymorphism in the Grey Partridge (Perdix perdix) is shaped by selection, recombination and gene conversion

Czech Academy of Sciences Publication Activity Database

Promerová, Marta; Králová, Tereza; Bryjová, Anna; Albrecht, Tomáš; Bryja, Josef

2013-01-01

Roč. 8, č. 7 (2013), e69135 E-ISSN 1932-6203 R&D Projects: GA ČR GA206/08/1281 Institutional support: RVO:68081766 Keywords : major histocompatibility complex (MHC) * snipe Gallinago-media * Class-I genes * minimal-essential-MHC Subject RIV: EG - Zoology Impact factor: 3.534, year: 2013

Thymic repopulation following intrathymic injection of mouse bone marrow cells in MHC matched and mismatched recipients

International Nuclear Information System (INIS)

Chervenak, R.

1986-01-01

T cell precursors (pre-T cells) have traditionally been detected by their ability to repopulate the thymus of heavily irradiated mice following intravenous injection. Recently, Goldschneider et. al. developed an assay system which involves the direct injection of pre-T cells into the thymus. The authors used this technique to evaluate the ability of bone marrow cells to repopulate thymuses in various donor-host strain combinations. Sub-lethally irradiated (600R) mice were injected intrathymically with 2 x 10 6 bone marrow cells which differed from the recipient with respect to their Thy 1 allotype. The percentage of thymus cells expressing either the donor or recipient type Thy 1 marker was determined 14 to 21 days after injection. These experiments showed that in MHC matched donor-host combinations (AKR/cum → AKR/J and CBA/J → AKR/J), cells derived from the donor inoculum accounted for 40% to 75% of the total thymus population. MHC mismatched donor-host combinations (C57BL/6J → AKR/J and Balb/c → AKR/J) resulted in significantly less donor-type repopulation of the thymus. In these cases, donor repopulation typically ranged from 0% to 4%. The ability of the pre-T cells detected by intrathymic injection to proliferate in the thymic environment, therefore, appears to be influenced by the MHC. This may reflect commitment of pre-T cells to MHC haplotype recognition prior to their migration to the thymus

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

a role for E7 in tumour immune evasion. We show that knockdown of E7 expression in HPV16- and HPV18-transformed cervical carcinoma cells by RNA interference increased expression of major histocompatibility complex (MHC) class I at the cell surface and reduced susceptibility of these cells to natural...... 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...

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

KAUST Repository

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

2014-01-01

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

Isolation of a 97-kb minimal essential MHC B locus from a new reverse-4D BAC library of the golden pheasant.

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Qing Ye

Full Text Available The bacterial artificial chromosome (BAC system is widely used in isolation of large genomic fragments of interest. Construction of a routine BAC library requires several months for picking clones and arraying BACs into superpools in order to employ 4D-PCR to screen positive BACs, which might be time-consuming and laborious. The major histocompatibility complex (MHC is a cluster of genes involved in the vertebrate immune system, and the classical avian MHC-B locus is a minimal essential one, occupying a 100-kb genomic region. In this study, we constructed a more effective reverse-4D BAC library for the golden pheasant, which first creates sub-libraries and then only picks clones of positive sub-libraries, and identified several MHC clones within thirty days. The full sequencing of a 97-kb reverse-4D BAC demonstrated that the golden pheasant MHC-B locus contained 20 genes and showed good synteny with that of the chicken. The notable differences between these two species were the numbers of class II B loci and NK genes and the inversions of the TAPBP gene and the TAP1-TAP2 region. Furthermore, the inverse TAP2-TAP1 was unique in the golden pheasant in comparison with that of chicken, turkey, and quail. The newly defined genomic structure of the golden pheasant MHC will give an insight into the evolutionary history of the avian MHC.

Expression, refolding and preliminary X-ray crystallographic analysis of equine MHC class I molecule complexed with an EIAV-Env CTL epitope

International Nuclear Information System (INIS)

Yao, Shugang; Qi, Jianxun; Liu, Jun; Chen, Rong; Pan, Xiaocheng; Li, Xiaoying; Gao, Feng; Xia, Chun

2011-01-01

The equine MHC class I molecule was crystallized in complex with β 2 -microglobulin and a CTL epitope and X-ray diffraction data were collected to 2.3 Å resolution. In order to clarify the structure and the peptide-presentation characteristics of the equine major histocompatibility complex (MHC) class I molecule, a complex of equine MHC class I molecule (ELA-A1 haplotype, 7-6 allele) with mouse β 2 -microglobulin and the cytotoxic T lymphocyte (CTL) epitope Env-RW12 (RVEDVTNTAEYW) derived from equine infectious anaemia virus (EIAV) envelope protein (residues 195–206) was refolded and crystallized. The crystal, which belonged to space group P2 1 , diffracted to 2.3 Å resolution and had unit-cell parameters a = 82.5, b = 71.4, c = 99.8 Å, β = 102.9°. The crystal structure contained two molecules in the asymmetric unit. These results should help to determine the first equine MHC class I molecule structure presenting an EIAV CTL epitope

Glatiramer Acetate Treatment Increases Stability of Spinal Synapses and Down Regulates MHC I during the Course of EAE

Science.gov (United States)

Scorisa, Juliana M.; Freria, Camila M.; Victorio, Sheila C.; Barbizan, Roberta; Zanon, Renata G.; Oliveira, Alexandre L. R.

2011-01-01

The recent discovery that the major histocompatibility complex of class I (MHC I) expression has a role in the synaptic elimination process, represented an insight into understanding the cross talk between neurons. In the present study, the possibility that glatiramer acetate (GA) treatment influences the MHC class I expression and the synaptic plasticity process in the spinal cord during the course of EAE was investigated. C57BL/6J mice were induced to EAE and submitted to treatment either with a placebo solution or with GA (0.05mg/animal, subcutaneously, on a daily basis). All the animals were sacrificed at the peak disease (14 days after induction) or at the point of recovery of the clinical signs (21 days after induction). The spinal cords were removed and submitted to immunohistochemical examination, Western blotting and transmission electron microscopy analysis. The results showed that GA treatment was able to decrease synaptic loss during the course of EAE, which correlates with the downregulation of the MHC I complex. The present results reinforce the neuroprotective role of GA treatment, by reducing synaptic loss during the course of the disease. Such action may be associated with the recently described role of MHC I regulation during the synaptic plasticity process. PMID:22043176

Distinctive CD8+ T cell and MHC class I signatures in polycythemia vera patients.

Science.gov (United States)

Cardoso, Elsa M; Esgalhado, André J; Patrão, Luís; Santos, Mónica; Neves, Vasco Pinto; Martinez, Jorge; Patto, Maria Assunção Vaz; Silva, Helena; Arosa, Fernando A

2018-05-22

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by overproduction of red blood cells. We have performed a comprehensive characterization of blood immune cells for expression of naïve and memory receptors as well as β 2 m-associated and β 2 m-free MHC class I heavy chains, also known as closed and open conformers, respectively, in PV patients and age-matched controls (CTR). We show that the peripheral CD3 + CD8 + T cell pool in PV patients is clearly divided into two discrete populations, a more granular CD3 + CD8 high T cell population enriched in effector-memory CD45RA + T cells (CD8 + TEMRA) when compared to CTR (P e., CD3 + CD8 int CD28 int . While the percentage of CD3 + CD8 int TN cells correlated positively with the number of erythrocytes, the percentage of CD3 + CD8 int TEMRA correlated negatively with the number of platelets. Finally, we report that PV patients' lymphocytes and monocytes display lower levels of closed (W6/32 + ) MHC-I conformers at the cell surface while exhibiting increased amounts of open (HC-10 + ) MHC-I conformers. The implications of this distinctive immune signature are discussed.

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

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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.

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

NARCIS (Netherlands)

Cavalli, G.; Hayashi, M.; Jin, Y.; Yorgov, D.; Santorico, S.A.; Holcomb, C.; Rastrou, M.; Erlich, H.; Tengesdal, I.W.; Dagna, L.; Neff, C.P.; Palmer, B.E.; Spritz, R.A.; Dinarello, C.A.

2016-01-01

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,

Does the parasite-mediated selection drive the MHC class IIB diversity in wild populations of European chub (Squalius cephalus)?

Science.gov (United States)

Seifertová, Mária; Jarkovský, Jiří; Šimková, Andrea

2016-04-01

The genes of major histocompatibility complex (MHC) provide an excellent opportunity to study host-parasite relationships because they are expected to evolve in response to parasites and variation in parasite communities. In this study, we investigated the potential role of parasite-mediated selection acting on MHC class IIB (DAB) genes in European chub (Squalius cephalus) natural populations. We found significant differences between populations in metazoan parasites, neutral and adaptive genetic diversities. The analyses based on pairwise data revealed that populations with dissimilar MHC allelic profiles were geographically distant populations with significantly different diversity in microsatellites and a dissimilar composition of parasite communities. The results from the generalized estimating equations method (GEE) on the level of individuals revealed that metazoan parasite load in European chub was influenced by the diversity of DAB alleles as well as by the diversity of neutral genetic markers and host traits reflecting condition and immunocompetence. The multivariate co-inertia analysis showed specific associations between DAB alleles and parasite species. DAB1-like alleles were more involved in associations with ectoparasites, while DAB3-like alleles were positively associated with endoparasites which could suggest potential differences between DAB genes caused by different selection pressure. Our study revealed that parasite-mediated selection is not the only variable affecting MHC diversity in European chub; however, we strongly support the role of neutral processes as the main driver of DAB diversity across populations. In addition, our study contributes to the understanding of the evolution of MHC genes in wild living fish.

Genomic structure and expression pattern of MHC IIα and IIβ genes reveal an unusual immune trait in lined seahorse Hippocampus erectus.

Science.gov (United States)

Luo, Wei; Wang, Xin; Qu, Hongyue; Qin, Geng; Zhang, Huixian; Lin, Qiang

2016-11-01

The major histocompatibility complex (MHC) genes are crucial in the adaptive immune system, and the gene duplication of MHC in animals can generally result in immune flexibility. In this study, we found that the lined seahorse (Hippocampus erectus) has only one gene copy number (GCN) of MHC IIα and IIβ, which is different from that in other teleosts. Together with the lack of spleen and gut-associated lymphatic tissue (GALT), the seahorse may be referred to as having a partial but natural "immunodeficiency". Highly variable amino acid residues were found in the IIα and IIβ domains, especially in the α1 and β1 domains with 9.62% and 8.43% allelic variation, respectively. Site models revealed seven and ten positively selected positions in the α1 and β1 domains, respectively. Real-time PCR experiments showed high expression levels of the MHC II genes in intestine (In), gill (Gi) and trunk kidney (TK) and medium in muscle (Mu) and brood pouch (BP), and the expression levels were significantly up-regulated after bacterial infection. Specially, relative higher expression level of both MHC IIα and IIβ was found in Mu and BP when compared with other fish species, in which MHC II is expressed negligibly in Mu. These results indicate that apart from TK, Gi and In, MU and BP play an important role in the immune response against pathogens in the seahorse. In conclusion, high allelic variation and strong positive selection in PBR and relative higher expression in MU and BP are speculated to partly compensate for the immunodeficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

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...

Structure of the Epstein-Barr virus gp42 protein bound to the MHC class II recepter HLA-DR1

Energy Technology Data Exchange (ETDEWEB)

Mullen, M.; Haan, K.M.; Longnecker, R.; Jardetzky, T.

2010-03-08

Epstein-Barr virus (EBV) causes infectious mononucleosis, establishes long-term latent infections, and is associated with a variety of human tumors. The EBV gp42 glycoprotein binds MHC class II molecules, playing a critical role in infection of B lymphocytes. EBV gp42 belongs to the C-type lectin superfamily, with homology to NK receptors of the immune system. We report the crystal structure of gp42 bound to the human MHC class II molecule HLA-DR1. The gp42 binds HLA-DR1 using a surface site that is distinct from the canonical lectin and NK receptor ligand binding sites. At the canonical ligand binding site, gp42 forms a large hydrophobic groove, which could interact with other ligands necessary for EBV entry, providing a mechanism for coupling MHC recognition and membrane fusion.

MHC class II DRB diversity in raccoons (Procyon lotor) reveals associations with raccoon rabies virus (Lyssavirus).

Science.gov (United States)

Srithayakumar, Vythegi; Castillo, Sarrah; Rosatte, Rick C; Kyle, Christopher J

2011-02-01

In North America, the raccoon rabies virus (RRV) is an endemic wildlife disease which causes acute encephalopathies and is a strong selective force on raccoons (Procyon lotor), with estimates of ∼85% of the population succumbing to the disease when epizootic. RRV is regarded as a lethal disease if untreated; therefore, no evolutionary response would be expected of raccoon populations. However, variable immune responses to RRV have been observed in raccoons indicating a potential for evolutionary adaptation. Studies of variation within the immunologically important major histocompatibility complex (MHC) have revealed relationships between MHC alleles and diseases in humans and other wildlife species. This enhances our understanding of how hosts and pathogens adapt and co-evolve. In this study, we used RRV as a model system to study host-pathogen interaction in raccoons from a challenge study and from four wild populations that differ in exposure times and viral lineages. We investigated the potential role of Prlo-DRB polymorphism in relation to susceptibility/resistance to RRV in 113 RRV positive and 143 RRV negative raccoons. Six alleles were found to be associated with RRV negative status and five alleles with RRV positive animals. We found variable patterns of MHC associations given the relative number of selective RRV sweeps in the studied regions and correlations between MHC diversity and RRV lineages. The allelic associations established provide insight into how the genetic variation of raccoons may affect the disease outcome and this can be used to examine similar associations between other rabies variants and their hosts.

Partial fast-to-slow conversion of regenerating rat fast-twitch muscle by chronic low-frequency stimulation.

Science.gov (United States)

Pette, Dirk; Sketelj, Janez; Skorjanc, Dejan; Leisner, Elmi; Traub, Irmtrud; Bajrović, Fajko

2002-01-01

Chronic low-frequency stimulation (CLFS) of rat fast-twitch muscles induces sequential transitions in myosin heavy chain (MHC) expression from MHCIIb --> MHCIId/x --> MHCIIa. However, the 'final' step of the fast-to-slow transition, i.e., the upregulation of MHCI, has been observed only after extremely long stimulation periods. Assuming that fibre degeneration/regeneration might be involved in the upregulation of slow myosin, we investigated the effects of CLFS on extensor digitorum longus (EDL) muscles regenerating after bupivacaine-induced fibre necrosis. Normal, non-regenerating muscles responded to both 30- and 60-day CLFS with fast MHC isoform transitions (MHCIIb --> MHCIId --> MHCIIa) and only slight increases in MHCI. CLFS of regenerating EDL muscles caused similar transitions among the fast isoforms but, in addition, caused significant increases in MHCI (to approximately 30% relative concentration). Stimulation periods of 30 and 60 days induced similar changes in the regenerating bupivacaine-treated muscles, indicating that the upregulation of slow myosin was restricted to regenerating fibres, but only during an early stage of regeneration. These results suggest that satellite cells and/or regenerating fast rat muscle fibres are capable of switching directly to a slow program under the influence of CLFS and, therefore, appear to be more malleable than adult fibres.

CD4+ T cell-mediated rejection of MHC class II-positive tumor cells is dependent on antigen secretion and indirect presentation on host APCs.

Science.gov (United States)

Haabeth, Ole Audun Werner; Fauskanger, Marte; Manzke, Melanie; Lundin, Katrin U; Corthay, Alexandre; Bogen, Bjarne; Tveita, Anders Aune

2018-05-11

Tumor-specific CD4+ T cells have been shown to mediate efficient anti-tumor immune responses against cancer. Such responses can occur through direct binding to MHC class II (MHC II)-expressing tumor cells or indirectly via activation of professional antigen-presenting cells (APC) that take up and present the tumor antigen. We have previously shown that CD4+ T cells reactive against an epitope within the Ig light chain variable region of a murine B cell lymphoma can reject established tumors. Given the presence of MHC II molecules at the surface of lymphoma cells, we investigated whether MHC II-restricted antigen presentation on tumor cells alone was required for rejection. Variants of the A20 B lymphoma cell line that either secreted or intracellularly retained different versions of the tumor-specific antigen revealed that antigen secretion by the MHC II-expressing tumor cells was essential both for the priming and effector phase of CD4+ T cell-driven anti-tumor immune responses. Consistent with this, genetic ablation of MHC II in tumor cells, both in the case of B lymphoma and B16 melanoma, did not preclude rejection of tumors by tumor antigen-specific CD4+ T cells in vivo. These findings demonstrate that MHC class II expression on tumor cells themselves is not required for CD4+ T cell-mediated rejection, and that indirect display on host APC is sufficient for effective tumor elimination. These results support the importance of tumor-infiltrating APC as mediators of tumor cell killing by CD4+ T cells. Copyright ©2018, American Association for Cancer Research.

Mortality selection during the 2003 European heat wave in three-spined sticklebacks: effects of parasites and MHC genotype

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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.

Tetraspan microdomains distinct from lipid rafts enrich select peptide-MHC class II complexes

Czech Academy of Sciences Publication Activity Database

Kropshofer, H.; Spindeldreher, S.; Rohn, T. A.; Platania, N.; Grygar, C.; Daniel, N.; Wolpl, A.; Langen, H.; Hořejší, Václav; Vogt, A. B.

2002-01-01

Roč. 3, č. 1 (2002), s. 61-68 ISSN 1529-2908 Institutional research plan: CEZ:AV0Z5052915 Keywords : MHC II * tetraspan microdomains * peptide presentation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 27.868, year: 2002

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....

MHC class I down-regulation: Tumour escape from immune surveillance? (Review)

Czech Academy of Sciences Publication Activity Database

Bubeník, Jan

2004-01-01

Roč. 25, č. 2 (2004), s. 487-491 ISSN 1019-6439 R&D Projects: GA MZd NC7148; GA ČR GA301/04/0492; GA AV ČR IAA5052203 Institutional research plan: CEZ:AV0Z5052915 Keywords : MHC class I- tumour cells * immune surveillance Subject RIV: EC - Immunology Impact factor: 3.056, year: 2004

Peptide-binding motifs of two common equine class I MHC molecules in Thoroughbred horses.

Science.gov (United States)

Bergmann, Tobias; Lindvall, Mikaela; Moore, Erin; Moore, Eugene; Sidney, John; Miller, Donald; Tallmadge, Rebecca L; Myers, Paisley T; Malaker, Stacy A; Shabanowitz, Jeffrey; Osterrieder, Nikolaus; Peters, Bjoern; Hunt, Donald F; Antczak, Douglas F; Sette, Alessandro

2017-05-01

Quantitative peptide-binding motifs of MHC class I alleles provide a valuable tool to efficiently identify putative T cell epitopes. Detailed information on equine MHC class I alleles is still very limited, and to date, only a single equine MHC class I allele, Eqca-1*00101 (ELA-A3 haplotype), has been characterized. The present study extends the number of characterized ELA class I specificities in two additional haplotypes found commonly in the Thoroughbred breed. Accordingly, we here report quantitative binding motifs for the ELA-A2 allele Eqca-16*00101 and the ELA-A9 allele Eqca-1*00201. Utilizing analyses of endogenously bound and eluted ligands and the screening of positional scanning combinatorial libraries, detailed and quantitative peptide-binding motifs were derived for both alleles. Eqca-16*00101 preferentially binds peptides with aliphatic/hydrophobic residues in position 2 and at the C-terminus, and Eqca-1*00201 has a preference for peptides with arginine in position 2 and hydrophobic/aliphatic residues at the C-terminus. Interestingly, the Eqca-16*00101 motif resembles that of the human HLA A02-supertype, while the Eqca-1*00201 motif resembles that of the HLA B27-supertype and two macaque class I alleles. It is expected that the identified motifs will facilitate the selection of candidate epitopes for the study of immune responses in horses.

Characterization of major histocompatibility complex (MHC DRB exon 2 and DRA exon 3 fragments in a primary terrestrial rabies vector (Procyon lotor.

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Sarrah Castillo

Full Text Available The major histocompatibility complex (MHC presents a unique system to explore links between genetic diversity and pathogens, as diversity within MHC is maintained in part by pathogen driven selection. While the majority of wildlife MHC studies have investigated species that are of conservation concern, here we characterize MHC variation in a common and broadly distributed species, the North American raccoon (Procyon lotor. Raccoons host an array of broadly distributed wildlife diseases (e.g., canine distemper, parvovirus and raccoon rabies virus and present important human health risks as they persist in high densities and in close proximity to humans and livestock. To further explore how genetic variation influences the spread and maintenance of disease in raccoons we characterized a fragment of MHC class II DRA exon 3 (250 bp and DRB exon 2 (228 bp. MHC DRA was found to be functionally monomorphic in the 32 individuals screened; whereas DRB exon 2 revealed 66 unique alleles among the 246 individuals screened. Between two and four alleles were observed in each individual suggesting we were amplifying a duplicated DRB locus. Nucleotide differences between DRB alleles ranged from 1 to 36 bp (0.4-15.8% divergence and translated into 1 to 21 (1.3-27.6% divergence amino acid differences. We detected a significant excess of nonsynonymous substitutions at the peptide binding region (P = 0.005, indicating that DRB exon 2 in raccoons has been influenced by positive selection. These data will form the basis of continued analyses into the spatial and temporal relationship of the raccoon rabies virus and the immunogenetic response in its primary host.

Ligation of major histocompatibility complex class I antigens (MHC-I) prevents apoptosis induced by Fas or SAPK/JNK activation in T-lymphoma cells

DEFF Research Database (Denmark)

Lamberth, K; Claesson, M H

2001-01-01

Early apoptosis in Jurkat T-lymphoma cells was induced by agonistic anti-Fas Ab or by anisomycin which activates the stress kinases SAPK/JNK. Apoptosis was inhibited by ligation of major histocompatibility complex class I antigens (MHC-I). MHC-I ligation induced upregulation of the anti......-apoptotic Bcl-2 protein and stabilized the mitochondrial membrane potential (Deltapsim). MHC-I ligation also prevented downregulation of Bcl-2 and destabilization of Deltapsim induced by anti-Fas Ab treatment or anisomycin exposure. Studies on three different Jurkat cell mutants deficient for src p56(lck), ZAP......-70 kinase, or TCR/CD3 gamma-chain showed that the cells undergo apoptosis after Fas ligation. Anisomycin exposure induced apoptosis in the src p56(lck)-deficient cell line but not in the two other mutant cell lines. Simultaneous cross-linking of MHC-I and Fas ligation inhibited apoptosis in the ZAP...

Clinicopathologic features of myositis patients with CD8-MHC-1 complex pathology.

Science.gov (United States)

Ikenaga, Chiseko; Kubota, Akatsuki; Kadoya, Masato; Taira, Kenichiro; Uchio, Naohiro; Hida, Ayumi; Maeda, Meiko Hashimoto; Nagashima, Yu; Ishiura, Hiroyuki; Kaida, Kenichi; Goto, Jun; Tsuji, Shoji; Shimizu, Jun

2017-09-05

To determine the clinical features of myositis patients with the histopathologic finding of CD8-positive T cells invading non-necrotic muscle fibers expressing major histocompatibility complex class 1 (CD8-MHC-1 complex), which is shared by polymyositis (PM) and inclusion body myositis (IBM), in relation to the p62 immunostaining pattern of muscle fibers. All 93 myositis patients with CD8-MHC-1 complex who were referred to our hospital from 1993 to 2015 were classified on the basis of the European Neuromuscular Center (ENMC) diagnostic criteria for IBM (Rose, 2013) or PM (Hoogendijk, 2004) and analyzed. The 93 patients included were 17 patients with PM, 70 patients with IBM, and 6 patients who neither met the criteria for PM nor IBM in terms of muscle weakness distribution (unclassifiable group). For these PM, IBM, and unclassifiable patients, their mean ages at diagnosis were 63, 70, and 64 years; autoimmune disease was present in 7 (41%), 13 (19%), and 4 (67%); hepatitis C virus infection was detected in 0%, 13 (20%), and 2 (33%); and p62 was immunopositive in 0%, 66 (94%), and 2 (33%), respectively. Of the treated patients, 11 of 16 PM patients and 4 of 6 p62-immunonegative patients in the unclassifiable group showed responses to immunotherapy, whereas all 44 patients with IBM and 2 p62-immunopositive patients in the unclassifiable group were unresponsive to immunotherapy. CD8-MHC-1 complex is present in patients with PM, IBM, or unclassifiable group. The data may serve as an argument for a trial of immunosuppressive treatment in p62-immunonegative patients with unclassifiable myositis. © 2017 American Academy of Neurology.

Pioglitazone reverses down-regulation of cardiac PPARγ expression in Zucker diabetic fatty rats

International Nuclear Information System (INIS)

Pelzer, Theo; Jazbutyte, Virginija; Arias-Loza, Paula Anahi; Segerer, Stephan; Lichtenwald, Margit; Law, Marilyn P.; Schaefers, Michael; Ertl, Georg; Neyses, Ludwig

2005-01-01

Peroxisome proliferator-activated receptor-γ (PPARγ) plays a critical role in peripheral glucose homeostasis and energy metabolism, and inhibits cardiac hypertrophy in non-diabetic animal models. The functional role of PPARγ in the diabetic heart, however, is not fully understood. Therefore, we analyzed cardiac gene expression, metabolic control, and cardiac glucose uptake in male Zucker diabetic fatty rats (ZDF fa/fa) and lean ZDF rats (+/+) treated with the high affinity PPARγ agonist pioglitazone or placebo from 12 to 24 weeks of age. Hyperglycemia, hyperinsulinemia, and hypertriglyceridemia as well as lower cardiac PPARγ, glucose transporter-4 and α-myosin heavy chain expression levels were detected in diabetic ZDF rats compared to lean animals. Pioglitazone increased body weight and improved metabolic control, cardiac PPARγ, glut-4, and α-MHC expression levels in diabetic ZDF rats. Cardiac [ 18 F]fluorodeoxyglucose uptake was not detectable by micro-PET studies in untreated and pioglitazone treated ZDF fa/fa rats but was observed after administration of insulin to pioglitazone treated ZDF fa/fa rats. PPARγ agonists favorably affect cardiac gene expression in type-2 diabetic rats via activation and up-regulation of cardiac PPARγ expression whereas improvement of impaired cardiac glucose uptake in advanced type-2 diabetes requires co-administration of insulin

Proteasome, transporter associated with antigen processing, and class I genes in the nurse shark Ginglymostoma cirratum: evidence for a stable class I region and MHC haplotype lineages.

Science.gov (United States)

Ohta, Yuko; McKinney, E Churchill; Criscitiello, Michael F; Flajnik, Martin F

2002-01-15

Cartilaginous fish (e.g., sharks) are derived from the oldest vertebrate ancestor having an adaptive immune system, and thus are key models for examining MHC evolution. Previously, family studies in two shark species showed that classical class I (UAA) and class II genes are genetically linked. In this study, we show that proteasome genes LMP2 and LMP7, shark-specific LMP7-like, and the TAP1/2 genes are linked to class I/II. Functional LMP7 and LMP7-like genes, as well as multiple LMP2 genes or gene fragments, are found only in some sharks, suggesting that different sets of peptides might be generated depending upon inherited MHC haplotypes. Cosmid clones bearing the MHC-linked classical class I genes were isolated and shown to contain proteasome gene fragments. A non-MHC-linked LMP7 gene also was identified on another cosmid, but only two exons of this gene were detected, closely linked to a class I pseudogene (UAA-NC2); this region probably resulted from a recent duplication and translocation from the functional MHC. Tight linkage of proteasome and class I genes, in comparison with gene organizations of other vertebrates, suggests a primordial MHC organization. Another nonclassical class I gene (UAA-NC1) was detected that is linked neither to MHC nor to UAA-NC2; its high level of sequence similarity to UAA suggests that UAA-NC1 also was recently derived from UAA and translocated from MHC. These data further support the principle of a primordial class I region with few class I genes. Finally, multiple paternities in one family were demonstrated, with potential segregation distortions.

Characterization of the Canine MHC Class I DLA-88*50101 Peptide Binding Motif as a Prerequisite for Canine T Cell Immunotherapy.

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Sharon M Barth

Full Text Available There are limitations in pre-clinical settings using mice as a basis for clinical development in humans. In cancer, similarities exist between humans and dogs; thus, the dog patient can be a link in the transition from laboratory research on mouse models to clinical trials in humans. Knowledge of the peptides presented on MHC molecules is fundamental for the development of highly specific T cell-based immunotherapies. This information is available for human MHC molecules but is absent for the canine MHC. In the present study, we characterized the binding motif of dog leukocyte antigen (DLA class I allele DLA-88*50101, using human C1R and K562 transfected cells expressing the DLA-88*50101 heavy chain. MHC class I immunoaffinity-purification revealed 3720 DLA-88*50101 derived peptides, which enabled the determination of major anchor positions. The characterized binding motif of DLA-88*50101 was similar to HLA-A*02:01. Peptide binding analyses on HLA-A*02:01 and DLA-88*50101 via flow cytometry showed weak binding of DLA-88*50101 derived peptides to HLA-A*02:01, and vice versa. Our results present for the first time a detailed peptide binding motif of the canine MHC class I allelic product DLA-88*50101. These data support the goal of establishing dogs as a suitable animal model for the evaluation and development of T cell-based cancer immunotherapies, benefiting both dog and human patients.

Antigen-specific T cell activation independently of the MHC: chimeric antigen receptor (CAR-redirected T cells.

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Hinrich eAbken

2013-11-01

Full Text Available Adoptive T cell therapy has recently shown powerful in initiating a lasting anti-tumor response with spectacular therapeutic success in some cases. Specific T cell therapy, however, is limited since a number of cancer cells are not recognized by T cells due to various mechanisms including the limited availability of tumor-specific T cells and deficiencies in antigen processing or major histocompatibility complex (MHC expression of cancer cells. To make adoptive cell therapy applicable for the broad variety of cancer entities, patient's T cells are engineered ex vivo with pre-defined specificity by a recombinant chimeric antigen receptor (CAR which consists in the extracellular part of an antibody-derived domain for binding with a tumor-associated antigen and in the intracellular part of a TCR-derived signaling moiety for T cell activation. The specificity of CAR mediated T cell recognition is defined by the antibody domain, is independent of MHC presentation and can be extended to any target for which an antibody is available. We discuss the advantages and limitations of MHC-independent T cell targeting by an engineered CAR and review most significant progress recently made in early stage clinical trials to treat cancer.

Proteolytic enzymes involved in MHC class I antigen processing: A guerrilla army that partners with the proteasome.

Science.gov (United States)

Lázaro, Silvia; Gamarra, David; Del Val, Margarita

2015-12-01

Major histocompatibility complex class I proteins (MHC-I) load short peptides derived from proteolytic cleavage of endogenous proteins in any cell of the body, in a process termed antigen processing and presentation. When the source proteins are altered self or encoded by a pathogen, recognition of peptide/MHC-I complexes at the plasma membrane leads to CD8(+) T-lymphocyte responses that clear infections and probably underlie tumor immune surveillance. On the other hand, presentation of self peptides may cause some types of autoimmunity. The peptides that are presented determine the specificity and efficiency of pathogen clearance or, conversely, of immunopathology. In this review we highlight the growing number of peptidases which, as a by-product of their regular activity, can generate peptide epitopes for immune surveillance. These ∼20 peptidases collectively behave as a guerrilla army partnering with the regular proteasome army in generating a variety of peptides for presentation by MHC-I and thus optimally signaling infection. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

The roles of MHC class II genes and post-translational modification in celiac disease.

Science.gov (United States)

Sollid, Ludvig M

2017-08-01

Our increasing understanding of the etiology of celiac disease, previously considered a simple food hypersensitivity disorder caused by an immune response to cereal gluten proteins, challenges established concepts of autoimmunity. HLA is a chief genetic determinant, and certain HLA-DQ allotypes predispose to the disease by presenting posttranslationally modified (deamidated) gluten peptides to CD4 + T cells. The deamidation of gluten peptides is mediated by transglutaminase 2. Strikingly, celiac disease patients generate highly disease-specific autoantibodies to the transglutaminase 2 enzyme. The dual role of transglutaminase 2 in celiac disease is hardly coincidental. This paper reviews the genetic mapping and involvement of MHC class II genes in disease pathogenesis, and discusses the evidence that MHC class II genes, via the involvement of transglutaminase 2, influence the generation of celiac disease-specific autoantibodies.

Structure of the superantigen staphylococcal enterotoxin B in complex with TCR and peptide-MHC demonstrates absence of TCR-peptide contacts.

Science.gov (United States)

Rödström, Karin E J; Elbing, Karin; Lindkvist-Petersson, Karin

2014-08-15

Superantigens are immune-stimulatory toxins produced by Staphylococcus aureus, which are able to interact with host immune receptors to induce a massive release of cytokines, causing toxic shock syndrome and possibly death. In this article, we present the x-ray structure of staphylococcal enterotoxin B (SEB) in complex with its receptors, the TCR and MHC class II, forming a ternary complex. The structure, in combination with functional analyses, clearly shows how SEB adopts a wedge-like position when binding to the β-chain of TCR, allowing for an interaction between the α-chain of TCR and MHC. Furthermore, the binding mode also circumvents contact between TCR and the peptide presented by MHC, which enables SEB to initiate a peptide-independent activation of T cells. Copyright © 2014 by The American Association of Immunologists, Inc.

75 FR 28685 - Colonial Bankshares, MHC, Vineland, NJ; Approval of Conversion Application

Science.gov (United States)

2010-05-21

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision [AC-41: OTS Nos. 04983, H-3879, and H-4714... May 14, 2010, the Office of Thrift Supervision approved the application of Colonial Bankshares, MHC, and Colonial Bank, Vineland, New Jersey, to convert to the stock form of organization. Copies of the...

High-throughput identification of potential minor histocompatibility antigens by MHC tetramer-based screening

DEFF Research Database (Denmark)

Hombrink, Pleun; Hadrup, Sine R; Bakker, Arne

2011-01-01

the technical feasibility of high-throughput analysis of antigen-specific T-cell responses in small patient samples. However, the high-sensitivity of this approach requires the use of potential epitope sets that are not solely based on MHC binding, to prevent the frequent detection of T-cell responses that lack......T-cell recognition of minor histocompatibility antigens (MiHA) plays an important role in the graft-versus-tumor (GVT) effect of allogeneic stem cell transplantation (allo-SCT). However, the number of MiHA identified to date remains limited, making clinical application of MiHA reactive T......MHC-tetramer-based enrichment and multi-color flow cytometry. Using this approach, 71 peptide-reactive T-cell populations were generated. The isolation of a T-cell line specifically recognizing target cells expressing the MAP4K1(IMA) antigen demonstrates that identification of MiHA through this approach is in principle...

Expression of Dihydropyridine and Ryanodine Receptors in Type IIA Fibers of Rat Skeletal Muscle

International Nuclear Information System (INIS)

Anttila, Katja; Mänttäri, Satu; Järvilehto, Matti

2007-01-01

In this study, the fiber type specificity of dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs) in different rat limb muscles was investigated. Western blot and histochemical analyses provided for the first time evidence that the expression of both receptors correlates to a specific myosin heavy chain (MHC) composition. We observed a significant (p=0.01) correlation between DHP as well as Ry receptor density and the expression of MHC IIa (correlation factor r=0.674 and r=0.645, respectively) in one slow-twitch, postural muscle (m. soleus), one mixed, fast-twitch muscle (m. gastrocnemius) and two fast-twitch muscles (m. rectus femoris, m. extensor digitorum longus). The highest DHP and Ry receptor density was found in the white part of m. rectus femoris (0.058±0.0060 and 0.057±0.0158 ODu, respectively). As expected, the highest relative percentage of MHC IIa was also found in the white part of m. rectus femoris (70.0±7.77%). Furthermore, histochemical experiments revealed that the IIA fibers stained most strongly for the fluorophore-conjugated receptor blockers. Our data clearly suggest that the expression of DHPRs and RyRs follows a fiber type-specific pattern, indicating an important role for these proteins in the maintenance of an effective Ca 2+ cycle in the fast contracting fiber type IIA

MHC polymorphism and disease resistance in Atlantic salmon (Salmo salar); facing pathogens with single expressed major histocompatibility class I and class II loci

NARCIS (Netherlands)

Grimholt, U.; Larsen, S.; Nordmo, R.; Midtlyng, P.; Kjoeglum, S.; Storset, A.; Saebo, S.; Stet, R.J.M.

2003-01-01

Few studies have yet addressed the functional aspects of MHC molecules in fish. To lay the foundation for this, we evaluated the association between disease resistance and MHC class I and class II polymorphism in Atlantic salmon. Standardized disease challenge trials were performed on a semi-wild

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

DEFF Research Database (Denmark)

Hoof, Ilka; Peters, B; Sidney, J

2009-01-01

molecules. We show that the NetMHCpan-2.0 method can accurately predict binding to uncharacterized HLA molecules, including HLA-C and HLA-G. Moreover, NetMHCpan-2.0 is demonstrated to accurately predict peptide binding to chimpanzee and macaque MHC class I molecules. The power of NetMHCpan-2.0 to guide...

TMEM129 is a Derlin-1 associated ERAD E3 ligase essential for virus-induced degradation of MHC-I.

Science.gov (United States)

van den Boomen, Dick J H; Timms, Richard T; Grice, Guinevere L; Stagg, Helen R; Skødt, Karsten; Dougan, Gordon; Nathan, James A; Lehner, Paul J

2014-08-05

The US11 gene product of human cytomegalovirus promotes viral immune evasion by hijacking the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. US11 initiates dislocation of newly translocated MHC I from the ER to the cytosol for proteasome-mediated degradation. Despite the critical role for ubiquitin in this degradation pathway, the responsible E3 ligase is unknown. In a forward genetic screen for host ERAD components hijacked by US11 in near-haploid KBM7 cells, we identified TMEM129, an uncharacterized polytopic membrane protein. TMEM129 is essential and rate-limiting for US11-mediated MHC-I degradation and acts as a novel ER resident E3 ubiquitin ligase. TMEM129 contains an unusual cysteine-only RING with intrinsic E3 ligase activity and is recruited to US11 via Derlin-1. Together with its E2 conjugase Ube2J2, TMEM129 is responsible for the ubiquitination, dislocation, and subsequent degradation of US11-associated MHC-I. US11 engages two degradation pathways: a Derlin-1/TMEM129-dependent pathway required for MHC-I degradation and a SEL1L/HRD1-dependent pathway required for "free" US11 degradation. Our data show that TMEM129 is a novel ERAD E3 ligase and the central component of a novel mammalian ERAD complex.

MHC-I-induced apoptosis in human B-lymphoma cells is dependent on protein tyrosine and serine/threonine kinases

DEFF Research Database (Denmark)

Pedersen, Anders Elm; Bregenholt, S; Johansen, B

1999-01-01

B lymphoma cells, is dependent on protein tyrosine kinases and the phosphatidylinositol 3 (PI-3) kinase. Functional studies showed that MHC-I crosslinking induced almost complete inhibition of the spontaneous proliferation of the B lymphoma cells as early as 6 h post-crosslinking and apoptosis 24 h...... post-crosslinking. Preincubation with either protein tyrosine kinase or protein serine/threonine kinase inhibitors reduced the MHC-I-induced apoptosis to background levels, whereas inhibition of PI-3 kinase had no effect. These data demonstrate a pivotal role for protein tyrosine and serine...

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...

Identification of T1D susceptibility genes within the MHC region by combining protein interaction networks and SNP genotyping data

DEFF Research Database (Denmark)

Brorsson, C.; Hansen, Niclas Tue; Hansen, Kasper Lage

2009-01-01

genes. We have developed a novel method that combines single nucleotide polymorphism (SNP) genotyping data with protein-protein interaction (ppi) networks to identify disease-associated network modules enriched for proteins encoded from the MHC region. Approximately 2500 SNPs located in the 4 Mb MHC......To develop novel methods for identifying new genes that contribute to the risk of developing type 1 diabetes within the Major Histocompatibility Complex (MHC) region on chromosome 6, independently of the known linkage disequilibrium (LD) between human leucocyte antigen (HLA)-DRB1, -DQA1, -DQB1...... region were analysed in 1000 affected offspring trios generated by the Type 1 Diabetes Genetics Consortium (T1DGC). The most associated SNP in each gene was chosen and genes were mapped to ppi networks for identification of interaction partners. The association testing and resulting interacting protein...

Enhancement of MHC-I antigen presentation via architectural control of pH-responsive, endosomolytic polymer nanoparticles.

Science.gov (United States)

Wilson, John T; Postma, Almar; Keller, Salka; Convertine, Anthony J; Moad, Graeme; Rizzardo, Ezio; Meagher, Laurence; Chiefari, John; Stayton, Patrick S

2015-03-01

Protein-based vaccines offer a number of important advantages over organism-based vaccines but generally elicit poor CD8(+) T cell responses. We have previously demonstrated that pH-responsive, endosomolytic polymers can enhance protein antigen delivery to major histocompatibility complex class I (MHC-I) antigen presentation pathways thereby augmenting CD8(+) T cell responses following immunization. Here, we describe a new family of nanocarriers for protein antigen delivery assembled using architecturally distinct pH-responsive polymers. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize linear, hyperbranched, and core-crosslinked copolymers of 2-(N,N-diethylamino)ethyl methacrylate (DEAEMA) and butyl methacrylate (BMA) that were subsequently chain extended with a hydrophilic N,N-dimethylacrylamide (DMA) segment copolymerized with thiol-reactive pyridyl disulfide (PDS) groups. In aqueous solution, polymer chains assembled into 25 nm micellar nanoparticles and enabled efficient and reducible conjugation of a thiolated protein antigen, ovalbumin. Polymers demonstrated pH-dependent membrane-destabilizing activity in an erythrocyte lysis assay, with the hyperbranched and cross-linked polymer architectures exhibiting significantly higher hemolysis at pH ≤ 7.0 than the linear diblock. Antigen delivery with the hyperbranched and cross-linked polymer architecture enhanced in vitro MHC-I antigen presentation relative to free antigen, whereas the linear construct did not have a discernible effect. The hyperbranched system elicited a four- to fivefold increase in MHC-I presentation relative to the cross-linked architecture, demonstrating the superior capacity of the hyperbranched architecture in enhancing MHC-I presentation. This work demonstrates that the architecture of pH-responsive, endosomolytic polymers can have dramatic effects on intracellular antigen delivery, and offers a promising strategy for enhancing CD8(+) T cell

Chemotherapy, IL-12 gene therapy and combined adjuvant therapy of HPV 16-associated MHC class I-proficient and -deficient tumours

Czech Academy of Sciences Publication Activity Database

Indrová, Marie; Bieblová, Jana; Jandlová, Táňa; Vonka, V.; Pajtasz-Piasecka, E.; Reiniš, Milan

2006-01-01

Roč. 28, č. 1 (2006), s. 253-260 ISSN 1019-6439 R&D Projects: GA MZd(CZ) NR7807; GA MZd(CZ) NR8004 Grant - others:Ministry of Scientific Research Information Society Technologies(PL) PBZ-KBN-091/PO5/2003 Institutional research plan: CEZ:AV0Z50520514 Keywords : HPV 16 * MHC class I-deficient and MHC class I-proficient tumour cells * CMRTD Subject RIV: EC - Immunology Impact factor: 2.556, year: 2006

Evolution of MHC-based technologies used for detection of antigen-responsive T cells

DEFF Research Database (Denmark)

Bentzen, Amalie Kai; Hadrup, Sine Reker

2017-01-01

T cell-mediated recognition of peptide-major histocompatibility complex (pMHC) class I and II molecules is crucial for the control of intracellular pathogens and cancer, as well as for stimulation and maintenance of efficient cytotoxic responses. Such interactions may also play a role in the deve...

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

potentials derived from the analysis of known protein structures; energetic evaluation of different peptide snapshots in a molecular dynamics simulation; and direct analysis of contacts made in known 3D structures of peptide:MHC complexes. These methods are ab initio in that they require structural data...

Establishment of a quantitative ELISA capable of determining peptide - MHC class I interaction

DEFF Research Database (Denmark)

Sylvester-Hvid, C; Kristensen, N; Blicher, T

2002-01-01

dependent manner. Here, we exploit the availability of these molecules to generate a quantitative ELISA-based assay capable of measuring the affinity of the interaction between peptide and MHC-I. This assay is simple and sensitive, and one can easily envisage that the necessary reagents, standards...

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

The major histocompatibility complex (MHC) genes are the most polymorphic genes found in the vertebrate genome, and they encode proteins that play an essential role in the adaptive immune response. Many songbirds (passerines) have been shown to have a large number of transcribed MHC class I genes...

Discovery of novel MHC-class I alleles and haplotypes in Filipino cynomolgus macaques (Macaca fascicularis) by pyrosequencing and Sanger sequencing: Mafa-class I polymorphism.

Science.gov (United States)

Shiina, Takashi; Yamada, Yukiho; Aarnink, Alice; Suzuki, Shingo; Masuya, Anri; Ito, Sayaka; Ido, Daisuke; Yamanaka, Hisashi; Iwatani, Chizuru; Tsuchiya, Hideaki; Ishigaki, Hirohito; Itoh, Yasushi; Ogasawara, Kazumasa; Kulski, Jerzy K; Blancher, Antoine

2015-10-01

Although the low polymorphism of the major histocompatibility complex (MHC) transplantation genes in the Filipino cynomolgus macaque (Macaca fascicularis) is expected to have important implications in the selection and breeding of animals for medical research, detailed polymorphism information is still lacking for many of the duplicated class I genes. To better elucidate the degree and types of MHC polymorphisms and haplotypes in the Filipino macaque population, we genotyped 127 unrelated animals by the Sanger sequencing method and high-resolution pyrosequencing and identified 112 different alleles, 28 at cynomolgus macaque MHC (Mafa)-A, 54 at Mafa-B, 12 at Mafa-I, 11 at Mafa-E, and seven at Mafa-F alleles, of which 56 were newly described. Of them, the newly discovered Mafa-A8*01:01 lineage allele had low nucleotide similarities (Filipino macaque population would identify these and other high-frequency Mafa-class I haplotypes that could be used as MHC control animals for the benefit of biomedical research.

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

A Novel Therapeutic Vaccine for Metastatic Mammary Carcinoma: Focusing MHC/Peptide Complexes to Lipid Rafts

National Research Council Canada - National Science Library

Dolan, Brian

2004-01-01

Genetic engineering of tumor cells to express MHC class and subsequent use of said cells for treatment of established and metastatic tumors has yielded promising results in animal models for treatment of breast cancer...

NetH2pan: A Computational Tool to Guide MHC peptide prediction on Murine Tumors

DEFF Research Database (Denmark)

DeVette, Christa I; Andreatta, Massimo; Bardet, Wilfried

2018-01-01

With the advancement of personalized cancer immunotherapies, new tools are needed to identify tumor antigens and evaluate T-cell responses in model systems, specifically those that exhibit clinically relevant tumor progression. Key transgenic mouse models of breast cancer are generated and mainta......With the advancement of personalized cancer immunotherapies, new tools are needed to identify tumor antigens and evaluate T-cell responses in model systems, specifically those that exhibit clinically relevant tumor progression. Key transgenic mouse models of breast cancer are generated...... for evaluating antigen specificity in the murine FVB strain. Our study provides the first detailed molecular and immunoproteomic characterization of the FVB H-2q MHC Class I alleles, including >8500 unique peptide ligands, a multi-allele murine MHC peptide prediction tool, and in vivo validation of these data...

Oriented coupling of major histocompatibility complex (MHC) to sensor surfaces using light assisted immobilisation technology

DEFF Research Database (Denmark)

Snabe, Torben; Røder, Gustav Andreas; Neves-Petersen, Maria Teresa

2005-01-01

Controlled and oriented immobilisation of proteins for biosensor purposes is of extreme interest since this provides more efficient sensors with a larger density of active binding sites per area compared to sensors produced by conventional immobilisation. In this paper oriented coupling of a major...... histocompatibility complex (MHC class I) to a sensor surface is presented. The coupling was performed using light assisted immobilisation--a novel immobilisation technology which allows specific opening of particular disulphide bridges in proteins which then is used for covalent bonding to thiol-derivatised surfaces...... via a new disulphide bond. Light assisted immobilisation specifically targets the disulphide bridge in the MHC-I molecule alpha(3)-domain which ensures oriented linking of the complex with the peptide binding site exposed away from the sensor surface. Structural analysis reveals that a similar...

Characterization of MHC class II B polymorphism in bottlenecked New Zealand saddlebacks reveals low levels of genetic diversity.

Science.gov (United States)

Sutton, Jolene T; Robertson, Bruce C; Grueber, Catherine E; Stanton, Jo-Ann L; Jamieson, Ian G

2013-08-01

The major histocompatibility complex (MHC) is integral to the vertebrate adaptive immune system. Characterizing diversity at functional MHC genes is invaluable for elucidating patterns of adaptive variation in wild populations, and is particularly interesting in species of conservation concern, which may suffer from reduced genetic diversity and compromised disease resilience. Here, we use next generation sequencing to investigate MHC class II B (MHCIIB) diversity in two sister taxa of New Zealand birds: South Island saddleback (SIS), Philesturnus carunculatus, and North Island saddleback (NIS), Philesturnus rufusater. These two species represent a passerine family outside the more extensively studied Passerida infraorder, and both have experienced historic bottlenecks. We examined exon 2 sequence data from populations that represent the majority of genetic diversity remaining in each species. A high level of locus co-amplification was detected, with from 1 to 4 and 3 to 12 putative alleles per individual for South and North Island birds, respectively. We found strong evidence for historic balancing selection in peptide-binding regions of putative alleles, and we identified a cluster combining non-classical loci and pseudogene sequences from both species, although no sequences were shared between the species. Fewer total alleles and fewer alleles per bird in SIS may be a consequence of their more severe bottleneck history; however, overall nucleotide diversity was similar between the species. Our characterization of MHCIIB diversity in two closely related species of New Zealand saddlebacks provides an important step in understanding the mechanisms shaping MHC diversity in wild, bottlenecked populations.

MHC class I cross-talk with CD2 and CD28 induces specific intracellular signalling and leads to growth retardation and apoptosis via a p56(lck)-dependent mechanism

DEFF Research Database (Denmark)

Ruhwald, M; Pedersen, Anders Elm; Claesson, M H

1999-01-01

Ligation of the major histocompatibility complex class I molecules (MHC-I) on human T lymphoma cells (Jurkat) initiates p56(lck)-dependent intracellular signalling events (phosphotyrosine kinase activity; [Ca(2+)](i)) and leads to augmented growth inhibition and apoptosis. MHC-I ligation in concert...... of apoptosis. In parallel experiments with the p56(lck)-negative Jurkat mutant cell, JCaM1.6, cross-linking neither influenced cell signalling nor cellular growth functions, indicating a cardinal role of the src kinases in signal transduction via MHC-I, CD2 and CD28 molecules. The results presented here...... with ligation of CD2 or CD28 augments, changes or modifies the pattern of activation. Ligation of MHC-I and CD2 alone resulted in growth inhibition, whereas CD28 ligation alone had no effect on cell proliferation. Ligation of MHC-I together with CD2 augmented growth inhibition and enhanced the level...

T lymphocytes from irradiation chimeras repopulated with 13-day fetal liver cells recognize antigens only in association with self-MHC products

International Nuclear Information System (INIS)

Nisbet-Brown, E.; Diener, E.

1986-01-01

The restriction specificities of maturing thymocytes are determined by the Class II MHC antigens expressed by non-lymphoid thymic tissues. The proliferative response of mature T lymphocytes to antigen-presenting cells (APC) and antigen requires that the APC express the same MHC antigens as the thymus in which the T cells differentiated. Thus, in the two-way bone marrow chimera [A + B----(A x B)F1], T lymphocyte populations of A and B haplotypes have each acquired the potential to recognize antigens associated with either parental haplotype. In spite of the large body of work on MHC restriction, we still do not have a clear understanding of the mechanisms which impose self restriction. The chimeric model systems used previously to study MHC restriction have used adult bone marrow cells as the source of lymphoid precursors. During normal ontogeny, T cells are derived from precursors in the fetal liver and we felt that a direct comparison of T cells from fetal liver and bone marrow-repopulated animals would shed light on the development of MHC restriction specificities during T cell ontogeny in the thymus or prethymically. We found that parental T lymphocyte populations isolated from two-way fetal liver chimeras cooperated only with syngeneic APC, while those from bone marrow chimeras cooperated with APC of either parental haplotype. This suggests that fetal liver and bone marrow may not be equivalent sources of stem cells. Our results may be due to fundamental differences between thymocyte precursors in fetal liver and bone marrow, including the time course of their expression of T cell receptor gene products

The diabetogenic mouse MHC class II molecule I-A[subscript g7] is endowed with a switch that modulates TCR affinity

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Kenji; Corper, Adam L.; Herro, Rana; Jabri, Bana; Wilson, Ian A.; Teyton, Luc (Scripps); (UC)

2011-11-16

Genetic susceptibility to autoimmunity is frequently associated with specific MHC alleles. Diabetogenic MHC class II molecules, such as human HLA-DQ8 and mouse I-A{sub g7}, typically have a small, uncharged amino acid residue at position 57 of their {beta} chain ({beta}57); this results in the absence of a salt bridge between {beta}57 and Arg{alpha}76, which is adjacent to the P9 pocket of the peptide-binding groove. However, the influence of Arg{alpha}76 on the selection of the TCR repertoire remains unknown, particularly when the MHC molecule binds a peptide with a neutral amino acid residue at position P9. Here, we have shown that diabetogenic MHC class II molecules bound to a peptide with a neutral P9 residue primarily selected and expanded cells expressing TCRs bearing a negatively charged residue in the first segment of their complementarity determining region 3{beta}. The crystal structure of one such TCR in complex with I-A{sub g7} bound to a peptide containing a neutral P9 residue revealed that a network of favorable long-range (greater than 4 {angstrom}) electrostatic interactions existed among Arg{alpha}76, the neutral P9 residue, and TCR, which supported the substantially increased TCR/peptide-MHC affinity. This network could be modulated or switched to a lower affinity interaction by the introduction of a negative charge at position P9 of the peptide. Our results support the existence of a switch at residue {beta}57 of the I-Ag7 and HLA-DQ8 class II molecules and potentially link normal thymic TCR selection with abnormal peripheral behavior.

Distinct spatial relationship of interleukin-9 receptor with IL-2R and MHC glycoproteins in human T lymphoma cells

OpenAIRE

Nizsalóczki, Enikő; Csomós, István; Nagy, Péter; Fazekas, Zsolt; Goldman, Carolyn K.; Waldmann, Thomas A.; Damjanovich, Sándor; Vámosi, György; Mátyus, László; Bodnár, Andrea

2014-01-01

The IL-9R consists of the α-subunit and the γc-chain shared with other cytokine receptors, including IL-2R, an important regulator of T cells. We have previously shown that IL-2R is expressed in common clusters with MHC glycoproteins in lipid rafts of human T lymphoma cells raising the question what the relationship between clusters of IL-2R/MHC and IL-9R is. Confocal microscopic co-localization and FRET experiments capable of detecting membrane protein organization at different size scales r...

Profiling MHC II immunopeptidome of blood-stage malaria reveals that cDC1 control the functionality of parasite-specific CD4 T cells.

Science.gov (United States)

Draheim, Marion; Wlodarczyk, Myriam F; Crozat, Karine; Saliou, Jean-Michel; Alayi, Tchilabalo Dilezitoko; Tomavo, Stanislas; Hassan, Ali; Salvioni, Anna; Demarta-Gatsi, Claudia; Sidney, John; Sette, Alessandro; Dalod, Marc; Berry, Antoine; Silvie, Olivier; Blanchard, Nicolas

2017-11-01

In malaria, CD4 Th1 and T follicular helper (T FH ) cells are important for controlling parasite growth, but Th1 cells also contribute to immunopathology. Moreover, various regulatory CD4 T-cell subsets are critical to hamper pathology. Yet the antigen-presenting cells controlling Th functionality, as well as the antigens recognized by CD4 T cells, are largely unknown. Here, we characterize the MHC II immunopeptidome presented by DC during blood-stage malaria in mice. We establish the immunodominance hierarchy of 14 MHC II ligands derived from conserved parasite proteins. Immunodominance is shaped differently whether blood stage is preceded or not by liver stage, but the same ETRAMP-specific dominant response develops in both contexts. In naïve mice and at the onset of cerebral malaria, CD8α + dendritic cells (cDC1) are superior to other DC subsets for MHC II presentation of the ETRAMP epitope. Using in vivo depletion of cDC1, we show that cDC1 promote parasite-specific Th1 cells and inhibit the development of IL-10 + CD4 T cells. This work profiles the P. berghei blood-stage MHC II immunopeptidome, highlights the potency of cDC1 to present malaria antigens on MHC II, and reveals a major role for cDC1 in regulating malaria-specific CD4 T-cell responses. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

Survival-variation within and between functional categories of the African multimammate rat

DEFF Research Database (Denmark)

Julliard, Romain; Leirs, Herwig; Stenseth, Nils Chr.

1999-01-01

in the population immediately after their first capture; (iv) subadults survival in later months is, however, positively related to density; and (v) adult survival shows negative density-dependence. 3. Both density-dependent and density-independent factors simultaneously determine stage-dependent survival variation...

Molecular Basis of Natural Killer Cell Tumor Target Recognition: The NKr/MHC Class I Complex

National Research Council Canada - National Science Library

Hasemann, Charles

1999-01-01

.... We have pursued this via the heterologous expression of wild type and mutant NK receptors for the purpose of the determination of the atomic structure of an NK receptor/ class I MHC complex via X-ray crystallography...

pH dependence of the interaction between immunogenic peptides and MHC class II molecules. Evidence for an acidic intracellular compartment being the organelle of interaction

DEFF Research Database (Denmark)

Mouritsen, S; Buus, Anette Stryhn; Petersen, B L

1992-01-01

and most notably in the endosome-lysosome compartment in which Ag processing is thought to occur. Thus, Ag processing and interaction with MHC class II molecules can potentially happen in the very same compartment. This yet undefined acidic compartment would have to contain proteolytic enzymes and MHC...

MHC Class II and CD9 in Human Eosinophils Localize to Detergent-Resistant Membrane Microdomains

Science.gov (United States)

Akuthota, Praveen; Melo, Rossana C. N.; Spencer, Lisa A.

2012-01-01

Eosinophils function in murine allergic airways inflammation as professional antigen-presenting cells (APCs). In murine professional APC cell types, optimal functioning of MHC Class II depends on its lateral association in plasma membranes and colocalization with the tetraspanin CD9 into detergent-resistant membrane microdomains (DRMs). With human eosinophils, we evaluated the localization of MHC Class II (HLA-DR) to DRMs and the functional significance of such localization. In granulocyte-macrophage colony-stimulating factor–stimulated human eosinophils, antibody cross-linked HLA-DR colocalized by immunofluorescence microscopy focally on plasma membranes with CD9 and the DRM marker ganglioside GM1. In addition, HLA-DR coimmunoprecipitates with CD9 after chemical cross-linking of CD9. HLA-DR and CD9 were localized by Western blotting in eosinophil DRM subcellular fractions. DRM disruption with the cholesterol-depleting agent methyl-β-cyclodextrin decreased eosinophil surface expression of HLA-DR and CD9. We show that CD9 is abundant on the surface of eosinophils, presenting the first electron microscopy data of the ultrastructural immunolocalization of CD9 in human eosinophils. Disruption of HLA-DR–containing DRMs decreased the ability of superantigen-loaded human eosinophils to stimulate CD4+ T-cell activation (CD69 expression), proliferation, and cytokine production. Our results, which demonstrate that eosinophil MHC Class II localizes to DRMs in association with CD9 in a functionally significant manner, represent a novel insight into the organization of the antigen presentation complex of human eosinophils. PMID:21885678

MHC Class II and CD9 in human eosinophils localize to detergent-resistant membrane microdomains.

Science.gov (United States)

Akuthota, Praveen; Melo, Rossana C N; Spencer, Lisa A; Weller, Peter F

2012-02-01

Eosinophils function in murine allergic airways inflammation as professional antigen-presenting cells (APCs). In murine professional APC cell types, optimal functioning of MHC Class II depends on its lateral association in plasma membranes and colocalization with the tetraspanin CD9 into detergent-resistant membrane microdomains (DRMs). With human eosinophils, we evaluated the localization of MHC Class II (HLA-DR) to DRMs and the functional significance of such localization. In granulocyte-macrophage colony-stimulating factor-stimulated human eosinophils, antibody cross-linked HLA-DR colocalized by immunofluorescence microscopy focally on plasma membranes with CD9 and the DRM marker ganglioside GM1. In addition, HLA-DR coimmunoprecipitates with CD9 after chemical cross-linking of CD9. HLA-DR and CD9 were localized by Western blotting in eosinophil DRM subcellular fractions. DRM disruption with the cholesterol-depleting agent methyl-β-cyclodextrin decreased eosinophil surface expression of HLA-DR and CD9. We show that CD9 is abundant on the surface of eosinophils, presenting the first electron microscopy data of the ultrastructural immunolocalization of CD9 in human eosinophils. Disruption of HLA-DR-containing DRMs decreased the ability of superantigen-loaded human eosinophils to stimulate CD4(+) T-cell activation (CD69 expression), proliferation, and cytokine production. Our results, which demonstrate that eosinophil MHC Class II localizes to DRMs in association with CD9 in a functionally significant manner, represent a novel insight into the organization of the antigen presentation complex of human eosinophils.

Extensive impact of saturated fatty acids on metabolic and cardiovascular profile in rats with diet-induced obesity: a canonical analysis.

Science.gov (United States)

Oliveira Junior, Silvio A; Padovani, Carlos R; Rodrigues, Sergio A; Silva, Nilza R; Martinez, Paula F; Campos, Dijon Hs; Okoshi, Marina P; Okoshi, Katashi; Dal-Pai, Maeli; Cicogna, Antonio C

2013-04-15

Although hypercaloric interventions are associated with nutritional, endocrine, metabolic, and cardiovascular disorders in obesity experiments, a rational distinction between the effects of excess adiposity and the individual roles of dietary macronutrients in relation to these disturbances has not previously been studied. This investigation analyzed the correlation between ingested macronutrients (including sucrose and saturated and unsaturated fatty acids) plus body adiposity and metabolic, hormonal, and cardiovascular effects in rats with diet-induced obesity. Normotensive Wistar-Kyoto rats were submitted to Control (CD; 3.2 Kcal/g) and Hypercaloric (HD; 4.6 Kcal/g) diets for 20 weeks followed by nutritional evaluation involving body weight and adiposity measurement. Metabolic and hormonal parameters included glycemia, insulin, insulin resistance, and leptin. Cardiovascular analysis included systolic blood pressure profile, echocardiography, morphometric study of myocardial morphology, and myosin heavy chain (MHC) protein expression. Canonical correlation analysis was used to evaluate the relationships between dietary macronutrients plus adiposity and metabolic, hormonal, and cardiovascular parameters. Although final group body weights did not differ, HD presented higher adiposity than CD. Diet induced hyperglycemia while insulin and leptin levels remained unchanged. In a cardiovascular context, systolic blood pressure increased with time only in HD. Additionally, in vivo echocardiography revealed cardiac hypertrophy and improved systolic performance in HD compared to CD; and while cardiomyocyte size was unchanged by diet, nuclear volume and collagen interstitial fraction both increased in HD. Also HD exhibited higher relative β-MHC content and β/α-MHC ratio than their Control counterparts. Importantly, body adiposity was weakly associated with cardiovascular effects, as saturated fatty acid intake was directly associated with most cardiac remodeling

LEW.1WR1 RATS DEVELOP AUTOIMMUNE DIABETES SPONTANEOUSLY AND IN RESPONSE TO ENVIRONMENTAL PERTURBATION

Science.gov (United States)

Mordes, John P.; Leif, Jean H.; Woda, Bruce A.; Flanagan, Joan F.; Greiner, Dale L.; Kislauskis, Edward H.; Tirabassi, Rebecca S.

2005-01-01

We describe a new rat model of autoimmune diabetes that arose in a major histocompatibility complex (MHC) congenic LEW rat. Spontaneous diabetes in LEW.1WR1 rats (RT1u/u/a) occurs with a cumulative frequency of ∼2% at a median age of 59 days. The disease is characterized by hyperglycemia, glycosuria, ketonuria and polyuria. Both sexes are affected, and islets of acutely diabetic rats are devoid of beta cells whereas alpha and delta cell populations are spared. The peripheral lymphoid phenotype is normal, including the fraction of ART2+ regulatory T cells (Tregs). We tested the hypothesis that the expression of diabetes would be increased by immunological perturbation of innate or adaptive immunity. Treatment of young rats with depleting anti-ART2.1 mAb increased the frequency of diabetes to 50%. Treatment with the toll-like receptor 3 (TLR3) ligand polyinosinic:polycytidylic acid increased the frequency of diabetes to 100%. All diabetic rats exhibited end-stage islets. The LEW.1WR1 rat is also susceptible to collagen-induced arthritis but is free of spontaneous thyroiditis. The LEW.1WR1 rat provides a new model for studying autoimmune diabetes and arthritis in an animal with a genetic predisposition to both disorders that can be amplified by environmental perturbation. PMID:16123363

MHC class I status of tumours and design of immunotherapeutic strategies

Czech Academy of Sciences Publication Activity Database

Bubeník, Jan; Vonka, V.

2003-01-01

Roč. 90, 2-3 (2003), s. 177-178 ISSN 0165-2478 R&D Projects: GA MZd NC7148; GA MZd NC3707; GA MZd NC6957; GA MZd NC7552; GA ČR GA301/01/0985; GA AV ČR IAA5052203 Institutional research plan: CEZ:AV0Z5052915 Keywords : MHC * beta2-mikroglobulin * immunotherapeutic strategies Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.710, year: 2003

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.

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.

Epitopes associated with MHC restriction site of T cells. III. I-J epitope on MHC-restricted T helper cells

International Nuclear Information System (INIS)

Asano, Y.; Nakayama, T.; Kubo, M.; Yagi, J.; Tada, T.

1987-01-01

I-J epitopes were found to be associated with the functional site of the class II MHC-restricted helper T (Th) cells: Virtually all of the H-2k-restricted Th cell function of H-2kxbF1 T cells was inhibited by the anti-I-Jk mAb, leaving the H-2b-restricted function unaffected. The I-Jk epitope was inducible in Th cells of different genotype origin according to the environmental class II antigens present in the early ontogeny of T cells. Although above results suggested that I-J is the structure reflecting the inducible MHC restriction specificity, further studies revealed some interesting controversies: First, the I-J phenotype did not always correlate with the class II restriction specificity, e.g., I-Ab-restricted Th from 5R was I-Jk-positive, whereas I-Ak-restricted Th of 4R was not. Second, there was no trans expression of parental I-J phenotypes and restriction specificities in F1 Th, e.g., the I-J phenotype was detected only on I-Ab-restricted Th of (4R X 5R)F1, whereas it was absent on I-Ak-restricted Th. This strict linkage between the restriction specificity and I-J phenotype was also found on Th cells developed in bone marrow chimera constructed with intra-H-2-recombinant mice. The expression of I-Jk was always associated with the restriction specificity of the relevant host. Thus, the restriction specificity of Th cells followed the host type, and the I-J expression on Th was exactly the same as that expressed by the host haplotype. These results indicate that I-J is an isomorphic structure adaptively expressed on Th cells that is involved in the unidirectional regulatory cell interactions, and that the polymorphism cannot be explained merely by the restriction specificity of the conventional T cell receptor heterodimer

Autoimmunity as a possible limiting selection pressure for the individual MHC IIB allele diversity in the three-spined stickleback Gasterosteus aculeatus?

OpenAIRE

Krause, A.

2011-01-01

Genetic diversity is a prerequisite for evolution. The genes of the Major Histocompatibility Complex (MHC) show genetic variation. They are polygenic and contain highly polymorphic loci. MHC molecules are an important part of the adaptive immune system due to their ability to bind and present different antigens to the T-lymphocytes. But this high specificity also implies a risk: the higher the number of recognized antigens, the more likely the similarity of foreign and auto antigens. This can...

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

International Nuclear Information System (INIS)

Li Jinliang; Srivastava, Tumul; Rawal, Ravindra; Manuel, Edwin; Isbell, Donna; Tsark, Walter; La Rosa, Corinna; Wang Zhongde; Li Zhongqi; Barry, Peter A.; Hagen, Katharine D.; Longmate, Jeffrey; Diamond, Don J.

2009-01-01

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-2K b domains) MHC Class I molecules were derived by transgenesis of the H-2K b D b double MHC Class I knockout strain. After immunization of Mamu-A*01/K b 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/K b 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.

Complex assembly, crystallization and preliminary X-ray crystallographic studies of rhesus macaque MHC Mamu-A*01 complexed with an immunodominant SIV-Gag nonapeptide

International Nuclear Information System (INIS)

Chu, Fuliang; Lou, Zhiyong; Gao, Bin; Bell, John I.; Rao, Zihe; Gao, George F.

2005-01-01

Crystallization of the first rhesus macaque MHC class I complex. Simian immunodeficiency virus (SIV) infection in rhesus macaques has been used as the best model for the study of human immunodeficiency virus (HIV) infection in humans, especially in the cytotoxic T-lymphocyte (CTL) response. However, the structure of rhesus macaque (or any other monkey model) major histocompatibility complex class I (MHC I) presenting a specific peptide (the ligand for CTL) has not yet been elucidated. Here, using in vitro refolding, the preparation of the complex of the rhesus macaque MHC I allele (Mamu-A*01) with human β 2 m and an immunodominant peptide, CTPYDINQM (Gag-CM9), derived from SIV Gag protein is reported. The complex (45 kDa) was crystallized; the crystal belongs to space group I422, with unit-cell parameters a = b = 183.8, c = 155.2 Å. The crystal contains two molecules in the asymmetric unit and diffracts X-rays to 2.8 Å resolution. The structure is being solved by molecular replacement and this is the first attempt to determined the crystal structure of a peptide–nonhuman primate MHC complex

Peptide-selective inrichment of MHC II-peptide complexes in tetraspan microdomains distinct from lipid rafts

Czech Academy of Sciences Publication Activity Database

Kropshofer, H.; Spindeldreher, S.; Rohn, T. A.; Platania, N.; Grygar, C.; Wolpl, A.; Langen, H.; Hořejší, Václav; Vogt, A. B.

2002-01-01

Roč. 3, č. 1 (2002), s. 61-68 ISSN 1529-2908 R&D Projects: GA MŠk LN00A026 Keywords : Microdomain * tetraspan proteins * MHC class II Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 27.868, year: 2002

In silico and in vivo analysis of Toxoplasma gondii epitopes by correlating survival data with peptide-MHC-I binding affinities.

Science.gov (United States)

Huang, Si-Yang; Jensen, Maria Risager; Rosenberg, Carina Agerbo; Zhu, Xing-Quan; Petersen, Eskild; Vorup-Jensen, Thomas

2016-07-01

Protein antigens comprising peptide motifs with high binding affinity to major histocompatibility complex class I (MHC-I) molecules are expected to induce a stronger cytotoxic T-lymphocyte response and thus provide better protection against infection with microorganisms where cytotoxic T-cells are the main effector arm of the immune system. Data on cyst formation and survival were extracted from past studies on the DNA immunization of mice with plasmids coding for Toxoplasma gondii antigens. From in silico analyses of the vaccine antigens, the correlation was tested between the predicted affinity for MHC-I molecules of the vaccine peptides and the survival of immunized mice after challenge with T. gondii. ELISPOT analysis was used for the experimental testing of peptide immunogenicity. Predictions for the Db MHC-I molecule produced a strong, negative correlation between survival and the dissociation constant of vaccine-derived peptides. The in silico analyses of nine T. gondii antigens identified peptides with a predicted dissociation constant in the interval from 10nM to 40μM. ELISPOT assays with splenocytes from T. gondii-infected mice further supported the importance of the peptide affinity for MHC-I. In silico analysis clearly helped the search for protective vaccine antigens. The ELISPOT analysis confirmed that the predicted T-cell epitopes were immunogenic by their ability to release interferon gamma in spleen cells. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Prevention of MHC-alloimmunization by UV-B irradiation in a murine model: effects of UV dose and number of transfused cells

International Nuclear Information System (INIS)

Grijzenhout, M.A.; Claas, F.H.J.

1994-01-01

The optimal dose of UV-B radiation for prevention of in vivo alloimmunization (AI) against major histocompatibility complex (MHC) antigens was investigated in a murine transfusion model. Two groups with five C57BL/6 mice (H-2 b ) each were transfused at weekly intervals with 1 x 10 5 or 1 x 10 6 DBA/2 (H-2 d ) leucocytes. Both suspensions induced anti-H-2 d antibodies in all mice after the second transfusion. The minimal UV-B dose required for abolition of alloreactivity in the mixed leucocyte reaction (MLR) was 0.6 J/cm 2 . This dose completely prevented the onset of MHC-AI in all five mice transfused with six suspensions containing 1 x 10 5 leucocytes. In contrast, suspensions with 1 x 10 6 leucocytes and exposed to 0.6 J/cm 2 induced immunization in 4/5 mice. Further increase of the dose to 1.8 or 5.4 J/cm 2 did not prevent the onset of MHC-AI. We conclude that the number of leucocytes per transfusion determines the efficacy of UV irradiation for the prevention of MHC-AI. For UV irradiation of human platelet concentrates (PCs) we propose to reduce the number of leucocytes by centrifugation prior to UV exposure. UV-B irradiation of PCs with high numbers of leucocytes may not be effective for prevention of alloimmunization. (Author)

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.

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.......3%) of the 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...

Bone morphogenic protein-2 regulates the myogenic differentiation of PMVECs in CBDL rat serum-induced pulmonary microvascular remodeling

Energy Technology Data Exchange (ETDEWEB)

Liu, Chang; Chen, Lin; Zeng, Jing; Cui, Jian; Ning, Jiao-nin [Department of Anesthesia, Southwest Hospital, The Third Military Medical University, Chongqing 400038 (China); Wang, Guan-song [Institute of Respiratory Disease, Xinqiao Hospital, The Third Military Medical University, Chongqing 400037 (China); Belguise, Karine; Wang, Xiaobo [Université P. Sabatier Toulouse III and CNRS, LBCMCP, 31062 Toulouse Cedex 9 (France); Qian, Gui-sheng [Institute of Respiratory Disease, Xinqiao Hospital, The Third Military Medical University, Chongqing 400037 (China); Lu, Kai-zhi [Department of Anesthesia, Southwest Hospital, The Third Military Medical University, Chongqing 400038 (China); Yi, Bin, E-mail: yibin1974@163.com [Department of Anesthesia, Southwest Hospital, The Third Military Medical University, Chongqing 400038 (China)

2015-08-01

Hepatopulmonary syndrome (HPS) is characterized by an arterial oxygenation defect induced by intrapulmonary vasodilation (IPVD) that increases morbidity and mortality. In our previous study, it was determined that both the proliferation and the myogenic differentiation of pulmonary microvascular endothelial cells (PMVECs) play a key role in the development of IPVD. However, the molecular mechanism underlying the relationship between IPVD and the myogenic differentiation of PMVECs remains unknown. Additionally, it has been shown that bone morphogenic protein-2 (BMP2), via the control of protein expression, may regulate cell differentiation including cardiomyocyte differentiation, neuronal differentiation and odontoblastic differentiation. In this study, we observed that common bile duct ligation (CBDL)-rat serum induced the upregulation of the expression of several myogenic proteins (SM-α-actin, calponin, SM-MHC) and enhanced the expression levels of BMP2 mRNA and protein in PMVECs. We also observed that both the expression levels of Smad1/5 and the activation of phosphorylated Smad1/5 were significantly elevated in PMVECs following exposure to CBDL-rat serum, which was accompanied by the down-regulation of Smurf1. The blockage of the BMP2/Smad signaling pathway with Noggin inhibited the myogenic differentiation of PMVECs, a process that was associated with relatively low expression levels of both SM-α-actin and calponin in the setting of CBDL-rat serum exposure, although SM-MHC expression was not affected. These findings suggested that the BMP2/Smad signaling pathway is involved in the myogenic differentiation of the PMVECs. In conclusion, our data highlight the pivotal role of BMP2 in the CBDL-rat serum-induced myogenic differentiation of PMVECs via the activation of both Smad1 and Smad5 and the down-regulation of Smurf1, which may represent a potential therapy for HPS-induced pulmonary vascular remodeling. - Highlights: • CBDL-rat serum promotes the myogenic

Increased projection of MHC and tumor antigens in murine B16-BL6 melanoma induced by hydrostatic pressure and chemical crosslinking.

Science.gov (United States)

Ramakrishna, V; Eisenthal, A; Skornick, Y; Shinitzky, M

1993-05-01

The B16-BL6 melanoma, like most spontaneously arising tumors, is poorly immunogenic and expresses low levels of major histocompatibility complex (MHC) antigens. Treatment of cells of this tumor in vitro by hydrostatic pressure in the presence of adenosine 2',3'-dialdehyde (oxAdo), a membrane-impermeant crosslinker, caused elevated projection of MHC and a specific tumor antigen as demonstrated by flow-cytometric analysis. Maximum projection of both the MHC and the tumor antigens could be reached by application of 1200 atm for 15 min in the presence of 20 mM oxAdo. It is not yet clear whether this passive increase in availability of antigens on the cell surface originated from a dormant pool of antigens in the plasma membrane or from pressure-induced fusion of antigen-rich intracellular organelles (e.g. the endoplasmic reticulum). The immunogenic properties of the antigen-enriched B16-BL6 cells are described in the following paper.

MHC class I dowregulation, tumour escape from immune surveillance and design of therapeutic strategies

Czech Academy of Sciences Publication Activity Database

Bubeník, Jan

2005-01-01

Roč. 51, č. 1 (2005), s. 1-2 ISSN 0015-5500 R&D Projects: GA ČR GA301/04/0492; GA MZd NR7807 Institutional research plan: CEZ:AV0Z50520514 Keywords : MHC class I * immune surveillance * immunotherapy Subject RIV: EC - Immunology Impact factor: 0.719, year: 2005

Measurement invariance of the Mental Health Continuum-Short Form (MHC-SF) across three cultural groups

NARCIS (Netherlands)

Joshanloo, Mohsen; Wissing, Marie P.; Khumalo, Itumeleng P.; Lamers, S.M.A.

2013-01-01

This study investigated the factorial structure and invariance of the Mental Health Continuum-Short Form (MHC-SF) across cultural groups from three nations, namely, the Netherlands, South Africa, and Iran (N = 1120). The three-dimensional structure of mental well-being was supported in all the

Isolation of a monoclonal antibody from a phage display library binding the rhesus macaque MHC class I allomorph Mamu-A1*001.

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Nathan Holman

Full Text Available Monoclonal antibodies that bind to human leukocyte antigen (HLA are useful tools for HLA-typing, tracking donor-recipient chimerisms after bone marrow transplants, and characterizing specific major histocompatibility complexes (MHC on cell surfaces. Unfortunately, equivalent reagents are not available for rhesus macaques, which are commonly used animal as models in organ transplant and infectious disease research. To address this deficiency, we isolated an antibody that recognizes the common Indian rhesus macaque MHC class I molecule, Mamu-A1*001. We induced Mamu-A1*001-binding antibodies by alloimmunizing a female Mamu-A1*001-negative rhesus macaque with peripheral blood mononuclear cells (PBMC from a male Mamu-A1*001-positive donor. A Fab phage display library was constructed with PBMC from the alloimmunized macaque and panned to isolate an antibody that binds to Mamu-A1*001 but not to other common rhesus macaque MHC class I molecules. The isolated antibody distinguishes PBMC from Mamu-A1*001-positive and -negative macaques. Additionally, the Mamu-A1*001-specific antibody binds the cynomolgus macaque MHC class I ortholog Mafa-A1*001:01 but not variants Mafa-A1*001:02/03, indicating a high degree of binding specificity. The Mamu-A1*001-specific antibody will be useful for identifying Mamu-A1*001-positive rhesus macaques, for detecting Mamu-A1*001-positive cells in populations of Mamu-A1*001-negative cells, and for examining disease processes that alter expression of Mamu-A1*001 on cell surfaces. Moreover, the alloimmunization process we describe will be useful for isolating additional MHC allomorph-specific monoclonal antibodies or antibodies against other polymorphic host proteins which are difficult to isolate with traditional technologies.

Sequence Variation of MHC Class II DQB Gene in Bottlenose Dolphin (Tursiops truncatus from Taiwanese Waters

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Wei-Cheng Yang

2008-03-01

Full Text Available The major histocompatibility complex (MHC is a large multigene coding for glycoproteins that play a key role in the initiation of immune responses in vertebrates. For a better understanding of the immunologic diversity in thriving marine mammal species, the sequence variation of the exon 2 region of MHC DQB locus was analyzed in 42 bottlenose dolphins (Tursiops truncatus collected from strandings and fishery bycatch in Taiwanese waters. The 172 bp sequences amplified showed no more than two alleles in each individual. The high proportion of non-synonymous nucleotide substitutions and the moderate amount of variation suggest positive selection pressure on this locus, arguing against a reduction in the marine environment selection pressure. The phylogenetic relationship among DQB exon 2 sequences of T. truncatus and other cetaceans did not coincide with taxonomic relationship, indicating a trans-species evolutionary pattern.

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

Science.gov (United States)

Follin, Elna; Karlsson, Maria; Lundegaard, Claus; Nielsen, Morten; Wallin, Stefan; Paulsson, Kajsa; Westerdahl, Helena

2013-04-01

The major histocompatibility complex (MHC) genes are the most polymorphic genes found in the vertebrate genome, and they encode proteins that play an essential role in the adaptive immune response. Many songbirds (passerines) have been shown to have a large number of transcribed MHC class I genes 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 their functional and genetic relationships. We found more pronounced clustering of the MHC class I allomorphs (allele specific proteins) in regards to their function (peptide-binding specificities) compared to their genetic relationships (amino acid sequences), indicating that the high number of alleles 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 function, possibly driven by selection from shared pathogens, has resulted in allomorphs with similar peptide-binding repertoires, although trans-species evolution in combination with gene conversion cannot be ruled out.

MHC polymorphism and disease resistance to vibrio anguillarum in 8 families of half-smooth tongue sole (Cynoglossus semilaevis

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Liu Yan-hong

2011-09-01

Full Text Available Abstract Background Genes in the major histocompatibility complex (MHC have a critical role in both the innate and adaptive immune responses because of their involvement in presenting foreign peptides to T cells. However, the nature has remained largely unknown. Results We examined the genetic variation in MHC class IIB in half-smooth tongue sole (Cynoglossus semilaevis after challenge with vibrio anguillarum. Two thousand and four hundred fry from 12 half-smooth tongue sole families were challenged with Vibrio anguillarum. To determine any association between alleles and resistance or susceptibility to V. anguillarum, 160 individuals from four high-resistance (HR, 73.27% mortality families were selected for MHC IIB exon2 gene sequence analysis. The MHC IIB exon2 genes of tongue sole displayed a high level of polymorphism and were discovered at least four loci. Meanwhile, the dN/dS [the ratio of non-synonymous (dN substitutions to synonymous (dS substitutions] in the peptide-binding region (PBR was higher than that in the non-peptide-binding region (non-PBR. Eighty-eight alleles were discovered among 160 individuals, and 13 out of 88 alleles were used to analyze the distribution pattern between the resistant and susceptible families. Certain alleles presented in HR and LR with a different frequency, while other alleles were discovered in only the HR or LR families, not both. Five alleles, Cyse-DBB*6501, Cyse-DBB*4002, Cyse-DBB*6102, Cyse-DBB*5601 and Cyse-DBB*2801, were found to be associated with susceptibility to V. anguillarum with a frequency of 1.25%, 1.25%, 1.25%, 1.25% and 2.5% in the HR families, and 35%, 33.75%, 27.5%, 16.25%, 15% in the LR families (p Cyse-DBB*3301, Cyse-DBB*4701, Cyse-DBB*6801 and Cyse-DBB*5901, were found to be associated with resistance to V. anguillarum, with a frequency of 13.75%, 11.25%, 11.25%, 8.75% in the HR families and 1.25%, 1.25%, 1.25%, 1.25% and 1.25% in the LR families (p Conclusions Elucidation of the

Antigen processing of glycoconjugate vaccines; the polysaccharide portion of the pneumococcal CRM(197) conjugate vaccine co-localizes with MHC II on the antigen processing cell surface.

Science.gov (United States)

Lai, Zengzu; Schreiber, John R

2009-05-21

Pneumococcal (Pn) polysaccharides (PS) are T-independent (TI) antigens and do not induce immunological memory or antibodies in infants. Conjugation of PnPS to the carrier protein CRM(197) induces PS-specific antibody in infants, and memory similar to T-dependent (Td) antigens. Conjugates have improved immunogenicity via antigen processing and presentation of carrier protein with MHC II and recruitment of T cell help, but the fate of the PS attached to the carrier is unknown. To determine the location of the PS component of PnPS-CRM(197) in the APC, we separately labeled PS and protein and tracked their location. The PS of types 14-CRM(197) and 19F-CRM(197) was specifically labeled by Alexa Fluor 594 hydrazide (red). The CRM(197) was separately labeled red in a reaction that did not label PS. Labeled antigens were incubated with APC which were fixed, permeabilized and incubated with anti-MHC II antibody labeled green by Alexa Fluor 488, followed by confocal microscopy. Labeled CRM(197) was presented on APC surface and co-localized with MHC II (yellow). Labeled unconjugated 14 or 19F PS did not go to the APC surface, but PS labeled 14-CRM(197) and 19F-CRM(197) was internalized and co-localized with MHC II. Monoclonal antibody to type 14 PS bound to intracellular type 14 PS and PS-CRM(197). Brefeldin A and chloroquine blocked both CRM(197) and PS labeled 14-CRM(197) and 19F-CRM(197) from co-localizing with MHC II. These data suggest that the PS component of the CRM(197) glycoconjugate enters the endosome, travels with CRM(197) peptides to the APC surface and co-localizes with MHC II.

Structural changes in the regenerating rat thymus after irradiation

Energy Technology Data Exchange (ETDEWEB)

Fukumoto, Tetsuo; Wang, Yu-Hsueh; Hashimoto, Noriko; Tokuda, Nobuko; Sawada, Tomoo [Yamaguchi Univ., Ube (Japan). School of Medicine

1999-11-01

The structural changes of the rat thymus after irradiation were examined. Thymocytes regenerate rapidly after irradiation and the mechanism responsible for this rapid regeneration was examined analyzing vascular and immunohistochemical changes in the thymus. Following results were obtained: Vascular fine mesh works in the cortex were destroyed on day 3 after 6 Gy irradiation, while on day 5 these changes appeared to be restored to almost normal. Massive macrophage accumulations were observed in the cortex on day 3-5 after irradiation. This may be due to clean up the damaged thymocytes, although other possibility, as production of cytokines which may contribute to the rapid proliferation must be intensively examined. Immunohistochemical staining with anti MHC class II molecule showed relatively strong staining in the medulla compared to the cortex in the normal thymus, while this finding was reversed and cortex stained heavily compared to the medulla on day 5-7 after irradiation suggesting the importance of the cortical MHC class II positive thymic epithelial cells in regeneration of thymocytes. Anti FTS antibody stained relatively strongly in the irradiated and recovering thymus compared to the normal. These results may partly explain the abrupt proliferation of thymocytes after irradiation and further studies on cytokine message changes and thymic epithelial characterization responsible to produce the cytokines for the effective thymocyte proliteration are on the way of analysis. (author)

Genetic variation at the MHC DRB1 locus is similar across Gunnison's prairie dog (Cynomys gunnisoni) colonies regardless of plague history

Science.gov (United States)

Cobble, Kacy R.; Califf, Katy J.; Stone, Nathan E.; Shuey, Megan M.; Birdsell, Dawn; Colman, Rebecca E.; Schupp, James M.; Aziz, Maliha; Van Andel, Roger; Rocke, Tonie E.; Wagner, David M.; Busch, Joseph D.

2016-01-01

Yersinia pestis was introduced to North America around 1900 and leads to nearly 100% mortality in prairie dog (Cynomys spp.) colonies during epizootic events, which suggests this pathogen may exert a strong selective force. We characterized genetic diversity at an MHC class II locus (DRB1) in Gunnison's prairie dog (C. gunnisoni) and quantified population genetic structure at the DRB1versus 12 microsatellite loci in three large Arizona colonies. Two colonies, Seligman (SE) and Espee Ranch (ES), have experienced multiple plague-related die-offs in recent years, whereas plague has never been documented at Aubrey Valley (AV). We found fairly low allelic diversity at the DRB1 locus, with one allele (DRB1*01) at high frequency (0.67–0.87) in all colonies. Two otherDRB1 alleles appear to be trans-species polymorphisms shared with the black-tailed prairie dog (C. ludovicianus), indicating that these alleles have been maintained across evolutionary time frames. Estimates of genetic differentiation were generally lower at the MHC locus (FST = 0.033) than at microsatellite markers (FST = 0.098). The reduced differentiation at DRB1 may indicate that selection has been important for shaping variation at MHC loci, regardless of the presence or absence of plague in recent decades. However, genetic drift has probably also influenced theDRB1 locus because its level of differentiation was not different from that of microsatellites in anFST outlier analysis. We then compared specific MHC alleles to plague survivorship in 60C. gunnisoni that had been experimentally infected with Y. pestis. We found that survival was greater in individuals that carried at least one copy of the most common allele (DRB1*01) compared to those that did not (60% vs. 20%). Although the sample sizes of these two groups were unbalanced, this result suggests the possibility that this MHC class II locus, or a nearby linked gene, could play a role in plague survival.

Variation in MHC class II B genes in marbled murrelets: implications for delineating conservation units

Science.gov (United States)

C. Vásquez-Carrillo; V. Friesen; L. Hall; M.Z. Peery

2013-01-01

Conserving genetic variation is critical for maintaining the evolutionary potential and viability of a species. Genetic studies seeking to delineate conservation units, however, typically focus on characterizing neutral genetic variation and may not identify populations harboring local adaptations. Here, variation at two major histocompatibility complex (MHC) class II...

Directed evolution of human T cell receptor CDR2 residues by phage display dramatically enhances affinity for cognate peptide-MHC without increasing apparent cross-reactivity

Science.gov (United States)

Dunn, Steven M.; Rizkallah, Pierre J.; Baston, Emma; Mahon, Tara; Cameron, Brian; Moysey, Ruth; Gao, Feng; Sami, Malkit; Boulter, Jonathan; Li, Yi; Jakobsen, Bent K.

2006-01-01

The mammalian α/β T cell receptor (TCR) repertoire plays a pivotal role in adaptive immunity by recognizing short, processed, peptide antigens bound in the context of a highly diverse family of cell-surface major histocompatibility complexes (pMHCs). Despite the extensive TCR–MHC interaction surface, peptide-independent cross-reactivity of native TCRs is generally avoided through cell-mediated selection of molecules with low inherent affinity for MHC. Here we show that, contrary to expectations, the germ line-encoded complementarity determining regions (CDRs) of human TCRs, namely the CDR2s, which appear to contact only the MHC surface and not the bound peptide, can be engineered to yield soluble low nanomolar affinity ligands that retain a surprisingly high degree of specificity for the cognate pMHC target. Structural investigation of one such CDR2 mutant implicates shape complementarity of the mutant CDR2 contact interfaces as being a key determinant of the increased affinity. Our results suggest that manipulation of germ line CDR2 loops may provide a useful route to the production of high-affinity TCRs with therapeutic and diagnostic potential. PMID:16600963

A novel protective MHC-I haplotype not associated with dominant Gag-specific CD8+ T-cell responses in SIVmac239 infection of Burmese rhesus macaques.

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Naofumi Takahashi

Full Text Available Several major histocompatibility complex class I (MHC-I alleles are associated with lower viral loads and slower disease progression in human immunodeficiency virus (HIV and simian immunodeficiency virus (SIV infections. Immune-correlates analyses in these MHC-I-related HIV/SIV controllers would lead to elucidation of the mechanism for viral control. Viral control associated with some protective MHC-I alleles is attributed to CD8+ T-cell responses targeting Gag epitopes. We have been trying to know the mechanism of SIV control in multiple groups of Burmese rhesus macaques sharing MHC-I genotypes at the haplotype level. Here, we found a protective MHC-I haplotype, 90-010-Id (D, which is not associated with dominant Gag-specific CD8+ T-cell responses. Viral loads in five D+ animals became significantly lower than those in our previous cohorts after 6 months. Most D+ animals showed predominant Nef-specific but not Gag-specific CD8+ T-cell responses after SIV challenge. Further analyses suggested two Nef-epitope-specific CD8+ T-cell responses exerting strong suppressive pressure on SIV replication. Another set of five D+ animals that received a prophylactic vaccine using a Gag-expressing Sendai virus vector showed significantly reduced viral loads compared to unvaccinated D+ animals at 3 months, suggesting rapid SIV control by Gag-specific CD8+ T-cell responses in addition to Nef-specific ones. These results present a pattern of SIV control with involvement of non-Gag antigen-specific CD8+ T-cell responses.

MHC class I ligation of human T cells activates the ZAP70 and p56lck tyrosine kinases, leads to an alternative phenotype of the TCR/CD3 zeta-chain, and induces apoptosis

DEFF Research Database (Denmark)

Skov, S; Bregenholt, S; Claesson, Mogens Helweg

1997-01-01

Cross-linking of MHC class I (MHC-I) molecules on human T cells induces signal-transduction events, including activation of tyrosine kinases, tyrosine phosphorylation of phospholipase C-gamma 1, and elevation of the intracellular free calcium concentration. In this study, we demonstrate...... that the ZAP70 tyrosine kinase is tyrosine phosphorylated in Jurkat T cells and in purified peripheral T cells after MHC-I ligation. The tyrosine-phosphorylated ZAP70 kinase exhibits a particular phenotype with low affinities for proteins at 21, 40, 60, and 120 kDa, proteins normally co-precipitated with ZAP70...... after TCR/CD3 stimulation. The phosphorylation of ZAP70 after MHC-I ligation was dependent on TCR/CD3 surface expression. One of the natural substrates for ZAP70 is the zeta-chain dimer of the TCR/CD3 complex. MHC-I cross-linking induces a phosphorylated zeta-protein that migrates as a dimer at 42 k...

Antigen presentation and MHC class II expression by human esophageal epithelial cells: role in eosinophilic esophagitis.

Science.gov (United States)

Mulder, Daniel J; Pooni, Aman; Mak, Nanette; Hurlbut, David J; Basta, Sameh; Justinich, Christopher J

2011-02-01

Professional antigen-presenting cells (APCs) play a crucial role in initiating immune responses. Under pathological conditions, epithelial cells at mucosal surfaces act as nonprofessional APCs, thereby regulating immune responses at the site of exposure. Epithelial cells in the esophagus may contribute to the pathogenesis of eosinophilic esophagitis (EoE) by presenting antigens on the major histocompatibility complex (MHC) class II. Our goal was to demonstrate the ability of esophageal epithelial cells to process and present antigens on the MHC class II system and to investigate the contribution of epithelial cell antigen presentation to EoE. Immunohistochemistry detected HLA-DR, CD80, and CD86 expression and enzyme-linked immunosorbent assay detected interferon-γ (IFNγ) in esophageal biopsies. Antigen presentation was studied using the human esophageal epithelial cell line HET-1A by reverse transcriptase-PCR, flow cytometry, and confocal microscopy. T helper cell lymphocyte proliferation was assessed by flow cytometry and IL-2 secretion. IFNγ and MHC class II were increased in mucosa of patients with EoE. IFNγ increased mRNA of HLA-DP, HLA-DQ, HLA-DR, and CIITA in HET-1A cells. HET-1A engulfed cell debris and processed ovalbumin. HET-1A cells expressed HLA-DR after IFNγ treatment. HET-1A stimulated T helper cell activation. In this study, we demonstrated the ability of esophageal epithelial cells to act as nonprofessional APCs in the presence of IFNγ. Esophageal epithelial cell antigen presentation may contribute to the pathophysiology of eosinophilic esophagitis. Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Positive selection on MHC class II DRB and DQB genes in the bank vole (Myodes glareolus).

Science.gov (United States)

Scherman, Kristin; Råberg, Lars; Westerdahl, Helena

2014-05-01

The major histocompatibility complex (MHC) class IIB genes show considerable sequence similarity between loci. The MHC class II DQB and DRB genes are known to exhibit a high level of polymorphism, most likely maintained by parasite-mediated selection. Studies of the MHC in wild rodents have focused on DRB, whilst DQB has been given much less attention. Here, we characterised DQB genes in Swedish bank voles Myodes glareolus, using full-length transcripts. We then designed primers that specifically amplify exon 2 from DRB (202 bp) and DQB (205 bp) and investigated molecular signatures of natural selection on DRB and DQB alleles. The presence of two separate gene clusters was confirmed using BLASTN and phylogenetic analysis, where our seven transcripts clustered according to either DQB or DRB homologues. These gene clusters were again confirmed on exon 2 data from 454-amplicon sequencing. Our DRB primers amplify a similar number of alleles per individual as previously published DRB primers, though our reads are longer. Traditional d N/d S analyses of DRB sequences in the bank vole have not found a conclusive signal of positive selection. Using a more advanced substitution model (the Kumar method) we found positive selection in the peptide binding region (PBR) of both DRB and DQB genes. Maximum likelihood models of codon substitutions detected positively selected sites located in the PBR of both DQB and DRB. Interestingly, these analyses detected at least twice as many positively selected sites in DQB than DRB, suggesting that DQB has been under stronger positive selection than DRB over evolutionary time.

Improved methods for predicting peptide binding affinity to MHC class II molecules

DEFF Research Database (Denmark)

Jensen, Kamilla Kjærgaard; Andreatta, Massimo; Marcatili, Paolo

2018-01-01

Major histocompatibility complex class II (MHC-II) molecules are expressed on the surface of professional antigen presenting cells where they display peptides to T helper cells, which orchestrate the onset and outcome of many host immune responses. Understanding which peptides will be presented b...... are publicly available at www.cbs.dtu.dk/services/NetMHCII-2.3 and www.cbs.dtu.dk/services/NetMHCIIpan-3.2. This article is protected by copyright. All rights reserved....

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

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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.

Sensitive quantitative predictions of peptide-MHC binding by a 'Query by Committee' artificial neural network approach

DEFF Research Database (Denmark)

Buus, S.; Lauemoller, S.L.; Worning, Peder

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...

Exploring the unbinding of Leishmania (L.) amazonensis CPB derived-epitopes from H2 MHC class I proteins.

Science.gov (United States)

Brandt, Artur M L; Batista, Paulo Ricardo; Souza-Silva, Franklin; Alves, Carlos Roberto; Caffarena, Ernesto Raul

2016-04-01

New strategies to control Leishmania disease demand an extensive knowledge about several aspects of infection including the understanding of its molecular events. In murine models, cysteine proteinase B from Leishmania amazonensis promotes regulation of immune response, and fragments from its C-terminus extension (cyspep) can play a decisive role in the host-parasite interaction. The interaction between cyspep-derived peptides and major histocompatibility complex (MHC) proteins is a crucial factor in Leishmania infections. Seven cyspep-derived peptides, previously identified as capable of interacting with H-2 (murine) MHC class I proteins, were studied in this work. We established a protocol to simulate the unbinding of these peptides from the cleft of H-2 receptors. From the simulations, we estimated the corresponding free energy of dissociation (ΔGd ) and described the molecular events that occur during the exit of peptides from the cleft. To test the reliability of this method, we first applied it to a calibration set of four crystallographic MHC/peptide complexes. Next, we explored the unbinding of the seven complexes mentioned above. Results were consistent with ΔGd values obtained from surface plasmon resonance (SPR) experiments. We also identified some of the primary interactions between peptides and H-2 receptors, and we detected three regions of influence for the interaction. This pattern was systematically observed for the peptides and helped determine a minimum distance for the real interaction between peptides and H-2 proteins occurring at ∼ 25 Å. © 2016 Wiley Periodicals, Inc.

The nomenclature of MHC class I gene regulatory regions - the case of two different downstream regulatory elements

Czech Academy of Sciences Publication Activity Database

Hatina, J.; Jansa, Petr; Forejt, Jiří

2001-01-01

Roč. 37, 12-13 (2001), s. 799-800 ISSN 0161-5890 Institutional research plan: CEZ:AV0Z5052915 Keywords : MHC I gene regulatory elements Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.973, year: 2001

Tubulation of class II MHC compartments is microtubule dependent and involves multiple endolysosomal membrane proteins in primary dendritic cells.

Science.gov (United States)

Vyas, Jatin M; Kim, You-Me; Artavanis-Tsakonas, Katerina; Love, J Christopher; Van der Veen, Annemarthe G; Ploegh, Hidde L

2007-06-01

Immature dendritic cells (DCs) capture exogenous Ags in the periphery for eventual processing in endolysosomes. Upon maturation by TLR agonists, DCs deliver peptide-loaded class II MHC molecules from these compartments to the cell surface via long tubular structures (endolysosomal tubules). The nature and rules that govern the movement of these DC compartments are unknown. In this study, we demonstrate that the tubules contain multiple proteins including the class II MHC molecules and LAMP1, a lysosomal resident protein, as well as CD63 and CD82, members of the tetraspanin family. Endolysosomal tubules can be stained with acidotropic dyes, indicating that they are extensions of lysosomes. However, the proper trafficking of class II MHC molecules themselves is not necessary for endolysosomal tubule formation. DCs lacking MyD88 can also form endolysosomal tubules, demonstrating that MyD88-dependent TLR activation is not necessary for the formation of this compartment. Endolysosomal tubules in DCs exhibit dynamic and saltatory movement, including bidirectional travel. Measured velocities are consistent with motor-based movement along microtubules. Indeed, nocodazole causes the collapse of endolysosomal tubules. In addition to its association with microtubules, endolysosomal tubules follow the plus ends of microtubules as visualized in primary DCs expressing end binding protein 1 (EB1)-enhanced GFP.

Peptide-binding motif prediction by using phage display library for SasaUBA*0301, a resistance haplotype of MHC class I molecule from Atlantic Salmon (Salmo salar)

DEFF Research Database (Denmark)

Zhao, Heng; Hermsen, Trudi; Stet, Rene J M

2008-01-01

The structure of the peptide-binding specificity of major histocompatibility complex (MHC) class I has been analyzed extensively in human and mouse. For fish, there are no crystallographic models of MHC molecules, neither are there data on the peptide-binding specificity. In this study, we descri...... and there is a significant association between MHC polymorphism and the disease resistance. Therefore, our study might contribute to designing a peptide vaccine against this viral disease....... class I molecule might have a very similar binding motif at the C-terminus compared with a known mouse class I molecule H2-Kb which has L, or I, V, M at p8. Previous work showed that Atlantic Salmon carrying the allele SasaUBA*0301 are resistant to infectious Salmon aneamia virus...

75 FR 28685 - Oritani Financial Corp., MHC, Township of Washington, NJ; Approval of Conversion Application

Science.gov (United States)

2010-05-21

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision [AC-39: OTS Nos. H-2944 and H-4701... hereby given that on May 10, 2010, the Office of Thrift Supervision approved the application of Oritani Financial Corp., MHC, and Oritani Bank, Township of Washington, New Jersey, to convert to the stock form of...

MHC-DQB1 Variation and Its Association with Resistance or Susceptibility to Cystic Echinococcosis in Chinese Merino Sheep

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Wenqiao Hui

2012-12-01

Full Text Available Cystic echinococcosis (CE, one of the world’s most geographically widespread diseases, still represents a considerable economic and public health significance, although a variety of methods has been used to control the disease. It has been demonstrated that genetic factors, especially variations in MHC loci, can influence the outcome of CE infection in the human population. The study described here was designed to determine whether variation in MHC-DQB1 was associated with susceptibility or resistance to CE in sheep. If so, it would lay a theoretical foundation for breeding disease resistance sheep in future. This study was carried out on 204 Chinese Merino sheep, including 101 CE sheep and 103 healthy controls. The polymorphism of MHC-DQB1 exon 2 was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP method, and x2 test was used to compare genotype frequencies between CE sheep and healthy controls. A total of 22 alleles and 42 genotypes were identified in DQB1 exon 2 in Chinese Merino sheep. In addition, x2 test showed that frequencies of DQB1-TaqIaa and DQB1-HaeIIInn genotypes were significantly higher in the healthy group (82.5% and 57.3%, respectively than that in the CE group (57.4% and 28.9%, respectively (both p values = 0, OR = 0.286, 0.303, respectively, suggesting that these genotypes appeared to be associated with resistance to CE. Whereas, frequencies of DQB1-TaqIab and DQB1-HaeIIImn genotypes were significantly higher in the CE group (36.9% and 32.0%, respectively, as compared with the healthy group (16.5% and 11.15%, respectively (p = 0.001, 0.001 and OR = 2.963, 3.629, respectively, indicating that these genotypes might be associated with susceptibility to CE. It is concluded that the genetic polymorphism within MHC-DQB1 might influence immune responses to pathogens, thus leading to the development of CE or protection against CE in Chinese Merino sheep, which would pave the way for breeding

Roles for common MLL/COMPASS subunits and the 19S proteasome in regulating CIITA pIV and MHC class II gene expression and promoter methylation.

Science.gov (United States)

Koues, Olivia I; Mehta, Ninad T; Truax, Agnieszka D; Dudley, R Kyle; Brooks, Jeanne K; Greer, Susanna F

2010-02-04

Studies indicate that the 19S proteasome contributes to chromatin reorganization, independent of the role the proteasome plays in protein degradation. We have previously shown that components of the 19S proteasome are crucial for regulating inducible histone activation events in mammalian cells. The 19S ATPase Sug1 binds to histone-remodeling enzymes, and in the absence of Sug1, a subset of activating epigenetic modifications including histone H3 acetylation, H3 lysine 4 trimethylation and H3 arginine 17 dimethylation are inhibited at cytokine-inducible major histocompatibilty complex (MHC)-II and class II transactivator (CIITA) promoters, implicating Sug1 in events required to initiate mammalian transcription. Our previous studies indicate that H3 lysine 4 trimethylation at cytokine-inducible MHC-II and CIITA promoters is dependent on proteolytic-independent functions of 19S ATPases. In this report, we show that multiple common subunits of the mixed lineage leukemia (MLL)/complex of proteins associated with Set I (COMPASS) complexes bind to the inducible MHC-II and CIITA promoters; that overexpressing a single common MLL/COMPASS subunit significantly enhances promoter activity and MHC-II HLA-DRA expression; and that these common subunits are important for H3 lysine 4 trimethylation at MHC-II and CIITA promoters. In addition, we show that H3 lysine 27 trimethylation, which is inversely correlated with H3 lysine 4 trimethylation, is significantly elevated in the presence of diminished 19S ATPase Sug1. Taken together, these experiments suggest that the 19S proteasome plays a crucial role in the initial reorganization of events enabling the relaxation of the repressive chromatin structure surrounding inducible promoters.

Roles for common MLL/COMPASS subunits and the 19S proteasome in regulating CIITA pIV and MHC class II gene expression and promoter methylation

Directory of Open Access Journals (Sweden)

Koues Olivia I

2010-02-01

Full Text Available Abstract Background Studies indicate that the 19S proteasome contributes to chromatin reorganization, independent of the role the proteasome plays in protein degradation. We have previously shown that components of the 19S proteasome are crucial for regulating inducible histone activation events in mammalian cells. The 19S ATPase Sug1 binds to histone-remodeling enzymes, and in the absence of Sug1, a subset of activating epigenetic modifications including histone H3 acetylation, H3 lysine 4 trimethylation and H3 arginine 17 dimethylation are inhibited at cytokine-inducible major histocompatibilty complex (MHC-II and class II transactivator (CIITA promoters, implicating Sug1 in events required to initiate mammalian transcription. Results Our previous studies indicate that H3 lysine 4 trimethylation at cytokine-inducible MHC-II and CIITA promoters is dependent on proteolytic-independent functions of 19S ATPases. In this report, we show that multiple common subunits of the mixed lineage leukemia (MLL/complex of proteins associated with Set I (COMPASS complexes bind to the inducible MHC-II and CIITA promoters; that overexpressing a single common MLL/COMPASS subunit significantly enhances promoter activity and MHC-II HLA-DRA expression; and that these common subunits are important for H3 lysine 4 trimethylation at MHC-II and CIITA promoters. In addition, we show that H3 lysine 27 trimethylation, which is inversely correlated with H3 lysine 4 trimethylation, is significantly elevated in the presence of diminished 19S ATPase Sug1. Conclusion Taken together, these experiments suggest that the 19S proteasome plays a crucial role in the initial reorganization of events enabling the relaxation of the repressive chromatin structure surrounding inducible promoters.

MHC class I–associated peptides derive from selective regions of the human genome

Science.gov (United States)

Pearson, Hillary; Granados, Diana Paola; Durette, Chantal; Bonneil, Eric; Courcelles, Mathieu; Rodenbrock, Anja; Laverdure, Jean-Philippe; Côté, Caroline; Thibault, Pierre

2016-01-01

MHC class I–associated peptides (MAPs) define the immune self for CD8+ T lymphocytes and are key targets of cancer immunosurveillance. Here, the goals of our work were to determine whether the entire set of protein-coding genes could generate MAPs and whether specific features influence the ability of discrete genes to generate MAPs. Using proteogenomics, we have identified 25,270 MAPs isolated from the B lymphocytes of 18 individuals who collectively expressed 27 high-frequency HLA-A,B allotypes. The entire MAP repertoire presented by these 27 allotypes covered only 10% of the exomic sequences expressed in B lymphocytes. Indeed, 41% of expressed protein-coding genes generated no MAPs, while 59% of genes generated up to 64 MAPs, often derived from adjacent regions and presented by different allotypes. We next identified several features of transcripts and proteins associated with efficient MAP production. From these data, we built a logistic regression model that predicts with good accuracy whether a gene generates MAPs. Our results show preferential selection of MAPs from a limited repertoire of proteins with distinctive features. The notion that the MHC class I immunopeptidome presents only a small fraction of the protein-coding genome for monitoring by the immune system has profound implications in autoimmunity and cancer immunology. PMID:27841757

Prolonged survival of isolated rat islet allografts pre-irradiated with X-rays

Energy Technology Data Exchange (ETDEWEB)

Kimura, Toshihisa; Note, Masayuki; Nakagawara, Gizo (Fukui Medical School, Matsuoka (Japan)); Kojima, Yasuhiko

1994-04-01

Prior to transplantation of islets, pre-incubation, or pre-irradiation may suppress the immunogenicity of islet cells without suppressing islet function. In the presently described experiments we investigated the use of X-ray irradiation prior to transplantation to reduce islet immunogenicity. To determine whether or not the islet function was reduced after irradiation, ACI rat islets were transplanted into the subrenal capsules of isogeneic rats which had been diabetic and examined the blood glucose level over a period of 40 days. The results indicated that irradiation injury was dose-dependent and that islets irradiated with over 80 Gy lost their function. Next, allogeneic transplantation was performed using the model of ACI rats to Lewis rats without the use of any immunosuppressive agent. Non-irradiated islets were rejected within 7 days. However 20 Gy or 40 Gy irradiated islets prolonged survival (18.7[+-]5.8 days (n=6) and 26.7[+-]10.0 days (n=6), respectively). To determine the basis for this effect, MHC expression of islets was examined by the immunoperoxidase technique. Immunohistologic studies showed that 40 Gy-irradiated islets were depleted of Class II antigen positive cells while Class I antigen expression was unchanged. These results suggest that the prolongation of islets survival by X-ray irradiation may possibly be due to, in part, the depletion of donor Class II antigen positive cells. (author).

Engineering chimeric human and mouse major histocompatibility complex (MHC) class I tetramers for the production of T-cell receptor (TCR) mimic antibodies

Science.gov (United States)

Bentley, Carol; Yates, Jenna; Salimi, Maryam; Greig, Jenny; Wiblin, Sarah; Hassanali, Tasneem; Banham, Alison H.

2017-01-01

Therapeutic monoclonal antibodies targeting cell surface or secreted antigens are among the most effective classes of novel immunotherapies. However, the majority of human proteins and established cancer biomarkers are intracellular. Peptides derived from these intracellular proteins are presented on the cell surface by major histocompatibility complex class I (MHC-I) and can be targeted by a novel class of T-cell receptor mimic (TCRm) antibodies that recognise similar epitopes to T-cell receptors. Humoural immune responses to MHC-I tetramers rarely generate TCRm antibodies and many antibodies recognise the α3 domain of MHC-I and β2 microglobulin (β2m) that are not directly involved in presenting the target peptide. Here we describe the production of functional chimeric human-murine HLA-A2-H2Dd tetramers and modifications that increase their bacterial expression and refolding efficiency. These chimeric tetramers were successfully used to generate TCRm antibodies against two epitopes derived from wild type tumour suppressor p53 (RMPEAAPPV and GLAPPQHLIRV) that have been used in vaccination studies. Immunisation with chimeric tetramers yielded no antibodies recognising the human α3 domain and β2m and generated TCRm antibodies capable of specifically recognising the target peptide/MHC-I complex in fully human tetramers and on the cell surface of peptide pulsed T2 cells. Chimeric tetramers represent novel immunogens for TCRm antibody production and may also improve the yield of tetramers for groups using these reagents to monitor CD8 T-cell immune responses in HLA-A2 transgenic mouse models of immunotherapy. PMID:28448627

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...

Polymorphisms in the F8 gene and MHC-II variants as risk factors for the development of inhibitory anti-factor VIII antibodies during the treatment of hemophilia a: a computational assessment.

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Gouri Shankar Pandey

Full Text Available The development of neutralizing anti-drug-antibodies to the Factor VIII protein-therapeutic is currently the most significant impediment to the effective management of hemophilia A. Common non-synonymous single nucleotide polymorphisms (ns-SNPs in the F8 gene occur as six haplotypes in the human population (denoted H1 to H6 of which H3 and H4 have been associated with an increased risk of developing anti-drug antibodies. There is evidence that CD4+ T-cell response is essential for the development of anti-drug antibodies and such a response requires the presentation of the peptides by the MHC-class-II (MHC-II molecules of the patient. We measured the binding and half-life of peptide-MHC-II complexes using synthetic peptides from regions of the Factor VIII protein where ns-SNPs occur and showed that these wild type peptides form stable complexes with six common MHC-II alleles, representing 46.5% of the North American population. Next, we compared the affinities computed by NetMHCIIpan, a neural network-based algorithm for MHC-II peptide binding prediction, to the experimentally measured values and concluded that these are in good agreement (area under the ROC-curve of 0.778 to 0.972 for the six MHC-II variants. Using a computational binding predictor, we were able to expand our analysis to (a include all wild type peptides spanning each polymorphic position; and (b consider more MHC-II variants, thus allowing for a better estimation of the risk for clinical manifestation of anti-drug antibodies in the entire population (or a specific sub-population. Analysis of these computational data confirmed that peptides which have the wild type sequence at positions where the polymorphisms associated with haplotypes H3, H4 and H5 occur bind MHC-II proteins significantly more than a negative control. Taken together, the experimental and computational results suggest that wild type peptides from polymorphic regions of FVIII constitute potential T-cell epitopes

Tubulation of Class II MHC Compartments Is Microtubule Dependent and Involves Multiple Endolysosomal Membrane Proteins in Primary Dendritic Cells1

Science.gov (United States)

Vyas, Jatin M.; Kim, You-Me; Artavanis-Tsakonas, Katerina; Love, J. Christopher; Van der Veen, Annemarthe G.; Ploegh, Hidde L.

2009-01-01

Immature dendritic cells (DCs) capture exogenous Ags in the periphery for eventual processing in endolysosomes. Upon maturation by TLR agonists, DCs deliver peptide-loaded class II MHC molecules from these compartments to the cell surface via long tubular structures (endolysosomal tubules). The nature and rules that govern the movement of these DC compartments are unknown. In this study, we demonstrate that the tubules contain multiple proteins including the class II MHC molecules and LAMP1, a lysosomal resident protein, as well as CD63 and CD82, members of the tetraspanin family. Endolysosomal tubules can be stained with acidotropic dyes, indicating that they are extensions of lysosomes. However, the proper trafficking of class II MHC molecules themselves is not necessary for endolysosomal tubule formation. DCs lacking MyD88 can also form endolysosomal tubules, demonstrating that MyD88-dependent TLR activation is not necessary for the formation of this compartment. Endolysosomal tubules in DCs exhibit dynamic and saltatory movement, including bidirectional travel. Measured velocities are consistent with motor-based movement along microtubules. Indeed, nocodazole causes the collapse of endolysosomal tubules. In addition to its association with microtubules, endolysosomal tubules follow the plus ends of microtubules as visualized in primary DCs expressing end binding protein 1 (EB1)-enhanced GFP. PMID:17513769

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...

Design of glycopeptides used to investigate class II MHC binding and T-cell responses associated with autoimmune arthritis.

Directory of Open Access Journals (Sweden)

Ida E Andersson

Full Text Available The glycopeptide fragment CII259-273 from type II collagen (CII binds to the murine A(q and human DR4 class II Major Histocompatibility Complex (MHC II proteins, which are associated with development of murine collagen-induced arthritis (CIA and rheumatoid arthritis (RA, respectively. It has been shown that CII259-273 can be used in therapeutic vaccination of CIA. This glycopeptide also elicits responses from T-cells obtained from RA patients, which indicates that it has an important role in RA as well. We now present a methodology for studies of (glycopeptide-receptor interactions based on a combination of structure-based virtual screening, ligand-based statistical molecular design and biological evaluations. This methodology included the design of a CII259-273 glycopeptide library in which two anchor positions crucial for binding in pockets of A(q and DR4 were varied. Synthesis and biological evaluation of the designed glycopeptides provided novel structure-activity relationship (SAR understanding of binding to A(q and DR4. Glycopeptides that retained high affinities for these MHC II proteins and induced strong responses in panels of T-cell hybridomas were also identified. An analysis of all the responses revealed groups of glycopeptides with different response patterns that are of high interest for vaccination studies in CIA. Moreover, the SAR understanding obtained in this study provides a platform for the design of second-generation glycopeptides with tuned MHC affinities and T-cell responses.

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. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Opposing motor activities of dynein and kinesin determine retention and transport of MHC class II-containing compartments

NARCIS (Netherlands)

Wubbolts, R.; Fernandez-Borja, M.; Jordens, I.; Reits, E.; Dusseljee, S.; Echeverri, C.; Vallee, R. B.; Neefjes, J.

1999-01-01

MHC class II molecules exert their function at the cell surface by presenting to T cells antigenic fragments that are generated in the endosomal pathway. The class II molecules are targetted to early lysosomal structures, termed MIIC, where they interact with antigenic fragments and are subsequently

Peptide binding motifs associated with MHC molecules common in Chinese rhesus macaques are analogous to those of human HLA supertypes, and include HLA-B27-like alleles

OpenAIRE

Mothé, Bianca R.; Southwood, Scott; Sidney, John; English, A. Michelle; Wriston, Amanda; Hoof, Ilka; Shabanowitz, Jeffrey; Hunt, Donald F.; Sette, Alessandro

2013-01-01

Chinese rhesus macaques are of particular interest in SIV/HIV research as these animals have prolonged kinetics of disease progression to AIDS, compared to their Indian counterparts, suggesting that they may be a better model for HIV. Nevertheless, the specific mechanism(s) accounting for these kinetics remains unclear. The study of Major Histocompatibility Complex (MHC) molecules, including their MHC:peptide binding motifs, provides valuable information for measuring cellular immune response...

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

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

Conformational variation of surface class II MHC proteins during myeloid dendritic cell differentiation accompanies structural changes in lysosomal MIIC

Czech Academy of Sciences Publication Activity Database

Potolicchio, I.; Chitta, S.; Xu, X.; Fonseca, D.; Crisi, G.; Hořejší, Václav; Strominger, J. L.; Stern, L. J.; Raposo, G.; Santambrogio, L.

2005-01-01

Roč. 175, č. 8 (2005), s. 4935-4947 ISSN 0022-1767 Institutional research plan: CEZ:AV0Z50520514 Keywords : MHC II * HLA-DR * dendritic cell Subject RIV: EC - Immunology Impact factor: 6.387, year: 2005

B-G cDNA clones have multiple small repeats and hybridize to both chicken MHC regions

DEFF Research Database (Denmark)

Kaufman, J; Salomonsen, J; Skjødt, K

1989-01-01

We used rabbit antisera to the chicken MHC erythrocyte molecule B-G and to the class I alpha chain (B-F) to screen lambda gt11 cDNA expression libraries made with RNA selected by oligo-dT from bone marrow cells of anemic B19 homozygous chickens. Eight clones were found to encode B-G molecules which...

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

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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.

OX62+OX6+OX35+ rat dendritic cells are unable to prime CD4+ T cells for an effective immune response following acute burn injury.

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Fazal, Nadeem

2013-01-01

Co-stimulatory molecules expressed on Dendritic Cells (DCs) function to coordinate an efficient immune response by T cells in the peripheral lymph nodes. We hypothesized that CD4+ T cell-mediated immune suppression following burn injury may be related to dysfunctional DCs residing in gut associated lymphoid tissues (GALT), such as Mesenteric Lymph Nodes (MLN). Therefore, we studied co-stimulatory molecules expressed on burn rat MLN DCs as an index of functional DCs that would mount an effective normal CD4+ T cell immune response. In a rat model of 30% Total Body Surface Area (TBSA) scald burn, OX62+OX6+OX35+ DCs and CD4+ T cells were isolated from MLN of day 3 post-burn and sham control rats. DCs were tested for their expression of co-stimulatory molecules, and prime CD4+ T cell (DC:CD4+T cell co-culture assays) to determine an effector immune response such as CD4+ T cell proliferation. The surface receptor expressions of MLN DCs co-stimulatory molecules, i.e., MHC-II, CD40, CD80 (B7-1), and CD86 (B7-2) were determined by Flow cytometry (quantitatively) and confocal microscopy (qualitatively). Tritiated thymidine and CFDA-SE determined CD4+ T cell proliferation following co-incubation with DCs. Cytokine milieu of MLN (IL-12 and IL-10) was assessed by mRNA determination by RT-PCR. The results showed down-regulated expressions of co-stimulatory markers (CD80, CD86, CD40 and MHC-II) of MLN DCs obtained from burn-injured rats, as well as lack of ability of these burn-induced DCs to stimulate CD4+ T cell proliferation in co-culture assays, as compared to the sham rats. Moreover, anti-CD40 stimulation of affected burn MLN DCs did not reverse this alteration. Furthermore, a marked up-regulation of mRNA IL-10 and down-regulation of mRNA IL-12 in burn MLN as compared to sham animals was also observed. To surmise, the data indicated that dysfunctional OX62+OX6+OX35+ rat MLN DCs may contribute to CD4+ T-cell-mediated immune suppression observed following acute burn injury.

OX62+OX6+OX35+ rat dendritic cells are unable to prime CD4+ T cells for an effective immune response following acute burn injury☆

Science.gov (United States)

Fazal, Nadeem

2013-01-01

Co-stimulatory molecules expressed on Dendritic Cells (DCs) function to coordinate an efficient immune response by T cells in the peripheral lymph nodes. We hypothesized that CD4+ T cell-mediated immune suppression following burn injury may be related to dysfunctional DCs residing in gut associated lymphoid tissues (GALT), such as Mesenteric Lymph Nodes (MLN). Therefore, we studied co-stimulatory molecules expressed on burn rat MLN DCs as an index of functional DCs that would mount an effective normal CD4+ T cell immune response. In a rat model of 30% Total Body Surface Area (TBSA) scald burn, OX62+OX6+OX35+ DCs and CD4+ T cells were isolated from MLN of day 3 post-burn and sham control rats. DCs were tested for their expression of co-stimulatory molecules, and prime CD4+ T cell (DC:CD4+T cell co-culture assays) to determine an effector immune response such as CD4+ T cell proliferation. The surface receptor expressions of MLN DCs co-stimulatory molecules, i.e., MHC-II, CD40, CD80 (B7-1), and CD86 (B7-2) were determined by Flow cytometry (quantitatively) and confocal microscopy (qualitatively). Tritiated thymidine and CFDA-SE determined CD4+ T cell proliferation following co-incubation with DCs. Cytokine milieu of MLN (IL-12 and IL-10) was assessed by mRNA determination by RT-PCR. The results showed down-regulated expressions of co-stimulatory markers (CD80, CD86, CD40 and MHC-II) of MLN DCs obtained from burn-injured rats, as well as lack of ability of these burn-induced DCs to stimulate CD4+ T cell proliferation in co-culture assays, as compared to the sham rats. Moreover, anti-CD40 stimulation of affected burn MLN DCs did not reverse this alteration. Furthermore, a marked up-regulation of mRNA IL-10 and down-regulation of mRNA IL-12 in burn MLN as compared to sham animals was also observed. To surmise, the data indicated that dysfunctional OX62+OX6+OX35+ rat MLN DCs may contribute to CD4+ T-cell-mediated immune suppression observed following acute burn injury

Haematological profile of rats (Rattus norvegicus) induced BCG and provided leaf extract of Plectranthus amboinicus Lour Spreng)

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Silitonga, Melva; Silitonga, Pasar M.

2017-08-01

Plectranthus amboinicus Lour Spreng is a medicinal plant that has many benefits, such as an antioxidant, hepatoprotective and immunostimulan. Immune status can be seen from hematological profile. This study aims to investigate hematology profile on rats induced BCG and leaf extract of Plectranthus amboinicus. 24 male rats aged 3 months and weighing between 140-200 grams divided equally into six groups, P0, P1, P2, P3, P4 and P5. P0 as controle was given aquadest. The P1, P2, P3, P4 and P5 treatment groups were given 19 g / kg AEP + BCG, 31.5 g / kg AEP + BCG, 19g / kg AEP, 31.5 g / kg AEP and BCG consecutively. The BCG were used as antigen. The AEP was administered orally for 30 days and 100 µl BCG were intramusculary administered on day 14 th and day 21. On day 31st, the rats we decapitated and their blood were collected for hematology (leucocyte (WBC), Erythrocyte (RBC), thrombocyte (PLT) count, Haemoglobin (Hb), erythrocyte sedimentation rate (ESR), MCV, MHC, and MHCH analysis. Data were analyzed with ANOVA. WBC increased significantly in treatment AEP 31.5 g / kg bw, 31.5 g AEP / kg bw + BCG and so were only given BCG. RBC tend to increase in all AEP treatment but tends to increase again when given a BCG. Hb increased in treatment P1, P2, T3 and P4, but the improvement was significant only in treatment P1. While PLT increase significantly in all treatments compared to the controls. HCT did not show significant differences but all of them were in the normal range. EAP without BCG and with the addition of BCG lowered ESR significantly, whereas BCG alone increased the ESR significantly. MCV increased significantly only in the treatment of P1 and show the same pattern with the MHC and MHCH. The conclusion that Plectranthus amboinicus Lour a positive impact on blood profiles with and without BCG. Plectranthus amboinicus Lour managed blood profile when administered together with BCG

Small mammals as hosts of immature ixodid ticks

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I.G. Horak

2005-09-01

Full Text Available Two hundred and twenty-five small mammals belonging to 16 species were examined for ticks in Free State, Mpumalanga and Limpopo Provinces, South Africa, and 18 ixodid tick species, of which two could only be identified to genus level, were recovered. Scrub hares, Lepus saxatilis, and Cape hares, Lepus capensis, harboured the largest number of tick species. In Free State Province Namaqua rock mice, Aethomys namaquensis, and four-striped grass mice, Rhabdomys pumilio, were good hosts of the immature stages of Haemaphysalis leachi and Rhipicephalus gertrudae, while in Mpumalanga and Limpopo Provinces red veld rats, Aethomys chrysophilus, Namaqua rock mice and Natal multimammate mice, Mastomys natalensis were good hosts of H. leachi and Rhipicephalus simus. Haemaphysalis leachi was the only tick recovered from animals in all three provinces.

Enhanced protein electrophoresis technique for separating human skeletal muscle myosin heavy chain isoforms

Science.gov (United States)

Bamman, M. M.; Clarke, M. S.; Talmadge, R. J.; Feeback, D. L.

1999-01-01

Talmadge and Roy (J. Appl. Physiol. 1993, 75, 2337-2340) previously established a sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) protocol for separating all four rat skeletal muscle myosin heavy chain (MHC) isoforms (MHC I, IIa, IIx, IIb); however, when applied to human muscle, the type II MHC isoforms (Ila, IIx) are not clearly distinguished. In this brief paper we describe a modification of the SDS-PAGE protocol which yields distinct and consistent separation of all three adult human MHC isoforms (MHC I, IIa, IIx) in a minigel system. MHC specificity of each band was confirmed by Western blot using three monoclonal IgG antibodies (mAbs) immunoreactive against MHCI (mAb MHCs, Novacastra Laboratories), MHCI+IIa (mAb BF-35), and MHCIIa+IIx (mAb SC-71). Results provide a valuable SDS-PAGE minigel technique for separating MHC isoforms in human muscle without the difficult task of casting gradient gels.

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...

Generation and characterization of peptide-specific, MHC-restricted cytotoxic T lymphocyte (CTL) and helper T cell lines from unprimed T cells under microculture conditions.

Science.gov (United States)

Sambhara, S R; Upadhya, A G; Miller, R G

1990-06-12

We describe a microculture system for the generation of CTL and T helper cells against peptides. Tryptic digest and cyanogen bromide fragments of chicken ovalbumin and synthetic peptides of ovalbumin (323-339) and influenza virus (NP 365-380) were used to generate CTL and T helper lines from unprimed T cells. These lines were both peptide-specific and MHC-restricted. The relative ease of generating peptide-specific, MHC-restricted CTL and helper T cell lines with as few as 10(6) unprimed lymphocytes can be an efficient method of detecting potential immunogenic determinants of an antigen.

Sensitive quantitative predictions of peptide-MHC binding by a 'Query by Committee' artificial neural network approach

DEFF Research Database (Denmark)

Buus, S.; Lauemoller, S.L.; Worning, Peder

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 bind...... of an iterative feedback loop whereby advanced, computational bioinformatics optimize experimental strategy, and vice versa....

A cell-based MHC stabilization assay for the detection of peptide binding to the canine classical class I molecule, DLA-88.

Science.gov (United States)

Ross, Peter; Holmes, Jennifer C; Gojanovich, Gregory S; Hess, Paul R

2012-12-15

Identifying immunodominant CTL epitopes is essential for studying CD8+ T-cell responses in populations, but remains difficult, as peptides within antigens typically are too numerous for all to be synthesized and screened. Instead, to facilitate discovery, in silico scanning of proteins for sequences that match the motif, or binding preferences, of the restricting MHC class I allele - the largest determinant of immunodominance - can be used to predict likely candidates. The high false positive rate with this analysis ideally requires binding confirmation, which is obtained routinely by an assay using cell lines such as RMA-S that have defective transporter associated with antigen processing (TAP) machinery, and consequently, few surface class I molecules. The stabilization and resultant increased life-span of peptide-MHC complexes on the cell surface by the addition of true binders validates their identity. To determine whether a similar assay could be developed for dogs, we transfected a prevalent class I allele, DLA-88*50801, into RMA-S. In the BARC3 clone, the recombinant heavy chain was associated with murine β2-microglobulin, and importantly, could differentiate motif-matched and -mismatched peptides by surface MHC stabilization. This work demonstrates the potential to use RMA-S cells transfected with canine alleles as a tool for CTL epitope discovery in this species. Copyright © 2012 Elsevier B.V. All rights reserved.

Immunomodulation of glioma cells after gene therapy: induction of major histocompatibility complex class I but not class II antigen in vitro.

Science.gov (United States)

Parsa, A T; Chi, J H; Hurley, P T; Jeyapalan, S A; Bruce, J N

2001-09-01

Acquired immunity has been demonstrated in Fischer rats bearing syngeneic 9L tumors after herpes simplex virus (HSV) thymidine kinase (TK) gene transfection and ganciclovir treatment. The nature of this immunity in rats and its relevance to the HSV TK/ganciclovir protocol for human subjects remain to be determined. In this study, levels of major histocompatibility complex (MHC) Class I and II antigen expression were measured before and after HSV TK transfection, in an effort to document immunomodulatory changes caused by gene therapy. Tumor cells from the 9L gliosarcoma cell line, three primary human glioma cultures, and the human glioma cell line U87 MG were transduced with HSV TK vector-containing supernatant from fibroblast-producing cells (titer of 5 x 10(6) colony-forming units/ml) and selected in G418 medium for neomycin resistance. Clones were pooled or individually selected for cell-killing assays with ganciclovir, to confirm TK expression (10(3) cells/well in a 96-well dish). Northern analyses using MHC Class I and Class II complementary deoxyribonucleic acid probes were performed on blots containing total ribonucleic acid from wild-type tumor cells and HSV TK transfectants. A beta-actin complementary deoxyribonucleic acid probe served as an internal control. Cell surface expression was confirmed with flow cytometry. The induction of MHC Class I was tested for cycloheximide and genistein sensitivity. All cell cultures exhibited increases in MHC Class I but not MHC Class II expression, as determined by Northern analysis densitometry and flow cytometry. Cycloheximide treatment did not diminish the up-regulation of MHC Class I after retroviral transfection, implicating a signal transduction pathway that does not require ongoing protein synthesis. Genistein pretreatment of cell cultures did diminish the up-regulation of MHC Class I, implicating a tyrosine kinase in the signaling cascade. Induction of MHC Class I in rat and human glioma cells after HSV TK

Microarray Analyses of Genes Differentially Expressed by Diet (Black Beans and Soy Flour) during Azoxymethane-Induced Colon Carcinogenesis in Rats.

Science.gov (United States)

Rondini, Elizabeth A; Bennink, Maurice R

2012-01-01

We previously demonstrated that black bean (BB) and soy flour (SF)-based diets inhibit azoxymethane (AOM)-induced colon cancer. The objective of this study was to identify genes altered by carcinogen treatment in normal-appearing colonic mucosa and those attenuated by bean feeding. Ninety-five male F344 rats were fed control (AIN) diets upon arrival. At 4 and 5 weeks, rats were injected with AOM (15 mg/kg) or saline and one week later administered an AIN, BB-, or SF-based diet. Rats were sacrificed after 31 weeks, and microarrays were conducted on RNA isolated from the distal colonic mucosa. AOM treatment induced a number of genes involved in immunity, including several MHC II-associated antigens and innate defense genes (RatNP-3, Lyz2, Pla2g2a). BB- and SF-fed rats exhibited a higher expression of genes involved in energy metabolism and water and sodium absorption and lower expression of innate (RatNP-3, Pla2g2a, Tlr4, Dmbt1) and cell cycle-associated (Cdc2, Ccnb1, Top2a) genes. Genes involved in the extracellular matrix (Col1a1, Fn1) and innate immunity (RatNP-3, Pla2g2a) were induced by AOM in all diets, but to a lower extent in bean-fed animals. This profile suggests beans inhibit colon carcinogenesis by modulating cellular kinetics and reducing inflammation, potentially by preserving mucosal barrier function.

Fiber type effects on contraction-stimulated glucose uptake and GLUT4 abundance in single fibers from rat skeletal muscle.

Science.gov (United States)

Castorena, Carlos M; Arias, Edward B; Sharma, Naveen; Bogan, Jonathan S; Cartee, Gregory D

2015-02-01

To fully understand skeletal muscle at the cellular level, it is essential to evaluate single muscle fibers. Accordingly, the major goals of this study were to determine if there are fiber type-related differences in single fibers from rat skeletal muscle for: 1) contraction-stimulated glucose uptake and/or 2) the abundance of GLUT4 and other metabolically relevant proteins. Paired epitrochlearis muscles isolated from Wistar rats were either electrically stimulated to contract (E-Stim) or remained resting (No E-Stim). Single fibers isolated from muscles incubated with 2-deoxy-d-[(3)H]glucose (2-DG) were used to determine fiber type [myosin heavy chain (MHC) isoform protein expression], 2-DG uptake, and abundance of metabolically relevant proteins, including the GLUT4 glucose transporter. E-Stim, relative to No E-Stim, fibers had greater (P contraction-stimulated glucose uptake. Copyright © 2015 the American Physiological Society.

Phenotypic heterogeneity of peripheral monocytes in healthy dogs.

Science.gov (United States)

Gibbons, Natalie; Goulart, Michelle R; Chang, Yu-Mei; Efstathiou, Konstantinos; Purcell, Robert; Wu, Ying; Peters, Laureen M; Turmaine, Mark; Szladovits, Balazs; Garden, Oliver A

2017-08-01

Monocytes are key cells of the innate immune system. Their phenotypic and functional roles have been investigated in humans, mice and other animals, such as the rat, pig and cow. To date, detailed phenotypic analysis of monocytes has not been undertaken in dogs. Two important surface markers in human monocytes are CD14 and MHC class II (MHC II). By flow cytometry, we demonstrated that canine monocytes can be subdivided into three separate populations: CD14 pos MHC II neg , CD14 pos MHC II pos and CD14 neg MHC II pos . Both light and transmission electron microscopy confirmed the monocytic identity of all three populations. The CD14 pos MHC II neg population could be distinguished on an ultrastructural level by their smaller size, the presence of more numerous, larger granules, and more pseudopodia than both of the other populations. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of sex, MHC, and age of recipients on the therapeutic effect of transferred leukocytes from cancer-resistant SR/CR mice

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Adams Jonathan M

2009-09-01

Full Text Available Abstract Background Spontaneous Regression/Complete Resistant (SR/CR mice are resistant to cancer through a mechanism that is mediated entirely by leukocytes of innate immunity. Transfer of leukocytes from SR/CR mice can confer cancer resistance in wild-type (WT recipients in both preventative and therapeutic settings. In the current studies, we investigated factors that may impact the efficacy and functionality of SR/CR donor leukocytes in recipients. Results In sex-mismatched transfers, functionality of female donor leukocytes was not affected in male recipients. In contrast, male donor leukocytes were greatly affected in the female recipients. In MHC-mismatches, recipients of different MHC backgrounds, or mice of different strains, showed a greater negative impact on donor leukocytes than sex-mismatches. The negative effects of sex-mismatch and MHC-mismatch on donor leukocytes were additive. Old donor leukocytes performed worse than young donor leukocytes in all settings including in young recipients. Young recipients were not able to revive the declining function of old donor leukocytes. However, the function of young donor leukocytes declined gradually in old recipients, suggesting that an aged environment may contain factors that are deleterious to cellular functions. The irradiation of donor leukocytes prior to transfers had a profound suppressive effect on donor leukocyte functions, possibly as a result of impaired transcription. The cryopreserving of donor leukocytes in liquid nitrogen had no apparent effect on donor leukocyte functions, except for a small loss of cell number after revival from freezing. Conclusion Despite the functional suppression of donor leukocytes in sex- and MHC-mismatched recipients, as well as old recipients, there was a therapeutic time period during the initial few weeks during which donor leukocytes were functional before their eventual rejection or functional decline. The eventual rejection of donor

75 FR 27863 - Savings Bank of Maine, MHC and Savings Bank of Maine, Gardiner, Maine; Approval of Conversion...

Science.gov (United States)

2010-05-18

... DEPARTMENT OF THE TREASURY Office of Thrift Supervision [AC-38: OTS Nos. 06947 and H 4709] Savings Bank of Maine, MHC and Savings Bank of Maine, Gardiner, Maine; Approval of Conversion Application Notice is hereby given that on May 7, 2010, the Office of Thrift Supervision approved the application of...

High-density mapping of the MHC identifies a shared role for HLA-DRB1*01:03 in inflammatory bowel diseases and heterozygous advantage in ulcerative colitis

DEFF Research Database (Denmark)

Goyette, Philippe; Boucher, Gabrielle; Mallon, Dermot

2015-01-01

high-density SNP typing of the MHC in >32,000 individuals with IBD, implicating multiple HLA alleles, with a primary role for HLA-DRB1*01:03 in both Crohn's disease and ulcerative colitis. Noteworthy differences were observed between these diseases, including a predominant role for class II HLA......Genome-wide association studies of the related chronic inflammatory bowel diseases (IBD) known as Crohn's disease and ulcerative colitis have shown strong evidence of association to the major histocompatibility complex (MHC). This region encodes a large number of immunological candidates, including...

CRISPR/Cas9-mediated targeting of the Rosa26 locus produces Cre reporter rat strains for monitoring Cre-loxP-mediated lineage tracing.

Science.gov (United States)

Ma, Yuanwu; Yu, Lei; Pan, Shuo; Gao, Shan; Chen, Wei; Zhang, Xu; Dong, Wei; Li, Jing; Zhou, Rui; Huang, Lan; Han, Yunlin; Bai, Lin; Zhang, Li; Zhang, Lianfeng

2017-10-01

The rat is an important laboratory animal for physiological, toxicological and pharmacological studies. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) is a simple and efficient tool to generate precise genetic modifications in rats, which will promote the accumulation of genetic resources and enable more precise studies of gene function. To monitor Cre-loxP-mediated excision in vivo, we generated a Cre reporter rat strain (Rosa26-imCherry) by knockin of a Cre reporter cassette at the Rosa26 locus using CRISPR/Cas9. Rosa26-imCherry rats exhibited inducible expression of the mCherry cassette (imCherry) using the Cre-loxP system, whereas normal rats exhibited ubiquitous expression of eGFP but not mCherry in the whole body. Injection of adeno-associated virus serotype 9-Cre into the hippocampus and skeletal muscle resulted in mCherry expression in virus-infected cells. Cre-loxP-mediated mCherry expression was then evaluated by crossing Rosa26-imCherry rats with transgenic rats ubiquitously expressing CAG-Cre, heart-specific α-MHC-Cre transgenic rats and liver-specific Alb-Cre knockin rats. Finally, using the established system the expression pattern of Cre driven by two endogenous gene promoters (Wfs1-Cre knockin rat, FabP2-Cre knockin rat) was traced. In summary, we demonstrated excision of the loxP-flanked allele in Rosa26-imCherry rats via activation of mCherry expression in the presence of Cre recombinase. This newly established Rosa26-imCherry rat strain represents a useful tool to facilitate Cre-expression pattern determination and tracing experiments. © 2017 Federation of European Biochemical Societies.

Expression, purification and preliminary X-ray crystallographic analysis of the chicken MHC class I molecule YF1*7.1

International Nuclear Information System (INIS)

Hee, Chee Seng; Gao, Song; Miller, Marcia M.; Goto, Ronald M.; Ziegler, Andreas; Daumke, Oliver; Uchanska-Ziegler, Barbara

2009-01-01

The chicken classical MHC class I antigen YF1*7.1 was crystallized together with β 2 -microglobulin but without a peptide ligand. Crystals diffracted synchrotron radiation to 1.32 Å and belonged to the monoclinic space group P2 1 . YF1*7.1 is an allele of a polymorphic major histocompatibility complex (MHC) class I-like locus within the chicken Y gene complex. With the aim of understanding the possible role of the YF1*7.1 molecule in antigen presentation, the complex of YF1*7.1 heavy chain and β 2 -microglobulin was reconstituted and purified without a peptide. Crystals diffracted synchrotron radiation to 1.32 Å resolution and belonged to the monoclinic space group P2 1 . The phase problem was solved by molecular replacement. A detailed examination of the structure may provide insight into the type of ligand that could be bound by the YF1*7.1 molecule

An MHC II-Dependent Activation Loop between Adipose Tissue Macrophages and CD4+ T Cells Controls Obesity-Induced Inflammation

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Kae Won Cho

2014-10-01

Full Text Available An adaptive immune response triggered by obesity is characterized by the activation of adipose tissue CD4+ T cells by unclear mechanisms. We have examined whether interactions between adipose tissue macrophages (ATMs and CD4+ T cells contribute to adipose tissue metainflammation. Intravital microscopy identifies dynamic antigen-dependent interactions between ATMs and T cells in visceral fat. Mice deficient in major histocompatibility complex class II (MHC II showed protection from diet-induced obesity. Deletion of MHC II expression in macrophages led to an adipose tissue-specific decrease in the effector/memory CD4+ T cells, attenuation of CD11c+ ATM accumulation, and improvement in glucose intolerance by increasing adipose tissue insulin sensitivity. Ablation experiments demonstrated that the maintenance of proliferating conventional T cells is dependent on signals from CD11c+ ATMs in obese mice. These studies demonstrate the importance of MHCII-restricted signals from ATMs that regulate adipose tissue T cell maturation and metainflammation.

(MASTOMYS) NATALENSIS

African Journals Online (AJOL)

MASTOMYS) NATALENSIS (A. SMITH) IN THE. TRANSVAAL HIGHVELD. C. G. COETZEE. Medical Ecology Centre, State Dept. of Health, Johannesburg·. INTRODUCTION. The multimammate mouse is one of the commonest and most widespread ...

Molecular characterization of MHC-DRB cDNA in water buffalo (Bubalus bubalis

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Soumen Naskar

2012-01-01

Full Text Available In the present study, water buffalo MHC (Bubu-DRB cDNA was cloned and characterized. The 1022 base long-amplified cDNA product encompassed a single open reading frame of 801 bases that coded for 266 amino acids. The Bubu-DRB sequence showed maximum homology with the BoLA-DRB3*0101 allele of cattle. A total of seven amino acid residues were found to be unique for the Bubu-DRB sequence. The majority of amino acid substitutions was observed in the β1 domain. Residues associated with important functions were mostly conserved. Water buffalo DRB was phylogenetically closer to goat DRB*A.

Skin allografts in lethally irradiated animals repopulated with syngeneic hemopoietic cells

International Nuclear Information System (INIS)

Schwadron, R.B.

1983-01-01

Total body irradiation and repopulation with syngeneic hemopoietic cells can be used to induce tolerance to major histocompatibility complex (MHC) mismatched heart and kidney grafts in rats and mice. However, this protocol does not work for MHC mismatched skin grafts in rats or mice. Furthermore, LEW rats that accept WF cardiac allografts after irradiation and repopulation reject subsequent WF skin grafts. Treatment of skin allograft donors with methotrexate prior to grafting onto irradiated and reconstituted mice resulted in doubling of the mean survival time. Analysis of which antigens provoked skin graft rejection by irradiation and reconstituted animals revealed the importance of I region antigens. Cardiac allograft acceptance by irradiated and reconstituted animals is mediated by suppressor cells found in the spleen. Adoptively tolerant LEW rats accepted WF skin grafts in 50% of grafted animals. Analysis of this phenomenon revealed that the adoptive transfer procedure itself was important in achieving skin allograft acceptance by these animals. In general, it seems that the lack of ability of irradiated and reconstituted animals to accept fully MHC disparate skin grafts results from the inability of these animals to suppress lymph node effector cells against I region antigen seen on highly immunogenic allogeneic Langerhans cells in the skin

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.

Mate choice for nonadditive genetic benefits correlate with MHC dissimilarity in the rose bitterling (Rhodeus ocellatus)

Czech Academy of Sciences Publication Activity Database

Agbali, M.; Reichard, Martin; Bryjová, Anna; Bryja, Josef; Smith, C.

2010-01-01

Roč. 64, č. 6 (2010), s. 1683-1696 ISSN 0014-3820 R&D Projects: GA AV ČR IAA600930608; GA ČR GA206/09/1163 Institutional research plan: CEZ:AV0Z60930519 Keywords : Additive genetic benefit * female mate choice * genetic compatibility * good genes * mate choice * MHC * nonadditive genetic benefit * olfactory cues * Rhodeus ocellatus * sexual selection Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.659, year: 2010

Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity

DEFF Research Database (Denmark)

Holm, Lars; Reitelseder, Søren; Pedersen, T.G.

2008-01-01

Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same indivi...... in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.......Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same.......05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy...

The Ia.2 Epitope Defines a Subset of Lipid Raft Resident MHC Class II Molecules Crucial to Effective Antigen Presentation1

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Busman-Sahay, Kathleen; Sargent, Elizabeth; Harton, Jonathan A.; Drake, James R.

2016-01-01

Previous work has established that binding of the 11-5.2 anti-I-Ak mAb, which recognizes the Ia.2 epitope on I-Ak class II molecules, elicits MHC class II signaling, whereas binding of two other anti-I-Ak mAb that recognize the Ia.17 epitope fail to elicit signaling. Using a biochemical approach, we establish that the Ia.2 epitope recognized by the widely used 11-5.2 mAb defines a subset of cell surface I-Ak molecules predominantly found within membrane lipid rafts. Functional studies demonstrate that the Ia.2 bearing subset of I-Ak class II molecules is critically necessary for effective B cell–T cell interactions especially at low antigen doses, a finding consistent with published studies on the role of raft-resident class II molecules in CD4 T cell activation. Interestingly, B cells expressing recombinant I-Ak class II molecules possessing a β chain-tethered HEL peptide lack the Ia.2 epitope and fail to partition into lipid rafts. Moreover, cells expressing Ia.2 negative tethered peptide-class II molecules are severely impaired in their ability to present both tethered peptide or peptide derived from exogenous antigen to CD4 T cells. These results establish the Ia.2 epitope as defining a lipid raft-resident MHC class II confomer vital to the initiation of MHC class II restricted B cell–T cell interactions. PMID:21543648

Docosahexaenoic acid modifies the clustering and size of lipid rafts and the lateral organization and surface expression of MHC class I of EL4 cells.

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Shaikh, Saame Raza; Rockett, Benjamin Drew; Salameh, Muhammad; Carraway, Kristen

2009-09-01

An emerging molecular mechanism by which docosahexaenoic acid (DHA) exerts its effects is modification of lipid raft organization. The biophysical model, based on studies with liposomes, shows that DHA avoids lipid rafts because of steric incompatibility between DHA and cholesterol. The model predicts that DHA does not directly modify rafts; rather, it incorporates into nonrafts to modify the lateral organization and/or conformation of membrane proteins, such as the major histocompatibility complex (MHC) class I. Here, we tested predictions of the model at a cellular level by incorporating oleic acid, eicosapentaenoic acid (EPA), and DHA, compared with a bovine serum albumin (BSA) control, into the membranes of EL4 cells. Quantitative microscopy showed that DHA, but not EPA, treatment, relative to the BSA control diminished lipid raft clustering and increased their size. Approximately 30% of DHA was incorporated directly into rafts without changing the distribution of cholesterol between rafts and nonrafts. Quantification of fluorescence colocalization images showed that DHA selectively altered MHC class I lateral organization by increasing the fraction of the nonraft protein into rafts compared with BSA. Both DHA and EPA treatments increased antibody binding to MHC class I compared with BSA. Antibody titration showed that DHA and EPA did not change MHC I conformation but increased total surface levels relative to BSA. Taken together, our findings are not in agreement with the biophysical model. Therefore, we propose a model that reconciles contradictory viewpoints from biophysical and cellular studies to explain how DHA modifies lipid rafts on several length scales. Our study supports the notion that rafts are an important target of DHA's mode of action.

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 II......) genes as some of the most significant differences between germinal center B-cell (GCB)-like DLBCL with full-length FOXP1 protein expression versus activated B-cell (ABC)-like DLBCL expressing predominantly short FOXP1 isoforms. In an independent primary DLBCL microarray data set, multiple MHC II genes......, including human leukocyte antigen DR alpha chain (HLA-DRA), were inversely correlated with FOXP1 transcript expression (PABC-DLBCL cells led to increased cell-surface expression of HLA-DRA and CD74. In R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone...

Longitudinal evaluation of the mental health continuum-short form (MHC-SF): Measurement invariance across demographics, physical illness, and mental illness

NARCIS (Netherlands)

Lamers, S.M.A.; Glas, Cornelis A.W.; Westerhof, Gerben Johan; Bohlmeijer, Ernst Thomas

2012-01-01

This study evaluated the measurement invariance of the Mental Health Continuum-Short Form (MHC-SF), a 14-item self-report questionnaire for measuring emotional, social, and psychological well-being. The study draws on data of a representative panel (Longitudinal Internet Studies for the Social

Lassa fever or lassa hemorrhagic fever risk to humans from rodent-borne zoonoses.

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El-Bahnasawy, Mamdouh M; Megahed, Laila Abdel-Mawla; Abdalla Saleh, Hala Ahmed; Morsy, Tosson A

2015-04-01

Viral hemorrhagic fevers (VHFs) typically manifest as rapidly progressing acute febrile syndromes with profound hemorrhagic manifestations and very high fatality rates. Lassa fever, an acute hemorrhagic fever characterized by fever, muscle aches, sore throat, nausea, vomiting, diarrhea and chest and abdominal pain. Rodents are important reservoirs of rodent-borne zoonosis worldwide. Transmission rodents to humans occur by aerosol spread, either from the genus Mastomys rodents' excreta (multimammate rat) or through the close contact with infected patients (nosocomial infection). Other rodents of the genera Rattus, Mus, Lemniscomys, and Praomys are incriminated rodents hosts. Now one may ask do the rodents' ectoparasites play a role in Lassa virus zoonotic transmission. This paper summarized the update knowledge on LHV; hopping it might be useful to the clinicians, nursing staff, laboratories' personals as well as those concerned zoonoses from rodents and rodent control.

Considerable MHC diversity suggests that the functional extinction of baiji is not related to population genetic collapse.

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Shixia Xu

Full Text Available To further extend our understanding of the mechanism causing the current nearly extinct status of the baiji (Lipotes vexillifer, one of the most critically endangered species in the world, genetic diversity at the major histocompatibility complex (MHC class II DRB locus was investigated in the baiji. Nine highly divergent DRB alleles were identified in 17 samples, with an average of 28.4 (13.2% nucleotide difference and 16.7 (23.5% amino acid difference between alleles. The unexpectedly high levels of DRB allelic diversity in the baiji may partly be attributable to its evolutionary adaptations to the freshwater environment which is regarded to have a higher parasite diversity compared to the marine environment. In addition, balancing selection was found to be the main mechanisms in generating sequence diversity at baiji DRB gene. Considerable sequence variation at the adaptive MHC genes despite of significant loss of neutral genetic variation in baiji genome might suggest that intense selection has overpowered random genetic drift as the main evolutionary forces, which further suggested that the critically endangered or nearly extinct status of the baiji is not an outcome of genetic collapse.

The optimization of peptide cargo bound to MHC class I molecules by the peptide-loading complex.

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Elliott, Tim; Williams, Anthony

2005-10-01

Major histocompatibility complex (MHC) class I complexes present peptides from both self and foreign intracellular proteins on the surface of most nucleated cells. The assembled heterotrimeric complexes consist of a polymorphic glycosylated heavy chain, non-polymorphic beta(2) microglobulin, and a peptide of typically nine amino acids in length. Assembly of the class I complexes occurs in the endoplasmic reticulum and is assisted by a number of chaperone molecules. A multimolecular unit termed the peptide-loading complex (PLC) is integral to this process. The PLC contains a peptide transporter (transporter associated with antigen processing), a thiooxido-reductase (ERp57), a glycoprotein chaperone (calreticulin), and tapasin, a class I-specific chaperone. We suggest that class I assembly involves a process of optimization where the peptide cargo of the complex is edited by the PLC. Furthermore, this selective peptide loading is biased toward peptides that have a longer off-rate from the assembled complex. We suggest that tapasin is the key chaperone that directs this action of the PLC with secondary contributions from calreticulin and possibly ERp57. We provide a framework model for how this may operate at the molecular level and draw parallels with the proposed mechanism of action of human leukocyte antigen-DM for MHC class II complex optimization.

Positive regulation of plasmacytoid dendritic cell function via Ly49Q recognition of class I MHC

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Tai, Lee-Hwa; Goulet, Marie-Line; Belanger, Simon; Toyama-Sorimachi, Noriko; Fodil-Cornu, Nassima; Vidal, Silvia M.; Troke, Angela D.; McVicar, Daniel W.; Makrigiannis, Andrew P.

2008-01-01

Plasmacytoid dendritic cells (pDCs) are an important source of type I interferon (IFN) during initial immune responses to viral infections. In mice, pDCs are uniquely characterized by high-level expression of Ly49Q, a C-type lectin-like receptor specific for class I major histocompatibility complex (MHC) molecules. Despite having a cytoplasmic immunoreceptor tyrosine-based inhibitory motif, Ly49Q was found to enhance pDC function in vitro, as pDC cytokine production in response to the Toll-like receptor (TLR) 9 agonist CpG-oligonucleotide (ODN) could be blocked using soluble monoclonal antibody (mAb) to Ly49Q or H-2Kb. Conversely, CpG-ODN–dependent IFN-α production by pDCs was greatly augmented upon receptor cross-linking using immobilized anti-Ly49Q mAb or recombinant H-2Kb ligand. Accordingly, Ly49Q-deficient pDCs displayed a severely reduced capacity to produce cytokines in response to TLR7 and TLR9 stimulation both in vitro and in vivo. Finally, TLR9-dependent antiviral responses were compromised in Ly49Q-null mice infected with mouse cytomegalovirus. Thus, class I MHC recognition by Ly49Q on pDCs is necessary for optimal activation of innate immune responses in vivo. PMID:19075287

Population genetics, community of parasites, and resistance to rodenticides in an urban brown rat (Rattus norvegicus) population.

Science.gov (United States)

Desvars-Larrive, Amélie; Pascal, Michel; Gasqui, Patrick; Cosson, Jean-François; Benoît, Etienne; Lattard, Virginie; Crespin, Laurent; Lorvelec, Olivier; Pisanu, Benoît; Teynié, Alexandre; Vayssier-Taussat, Muriel; Bonnet, Sarah; Marianneau, Philippe; Lacôte, Sandra; Bourhy, Pascale; Berny, Philippe; Pavio, Nicole; Le Poder, Sophie; Gilot-Fromont, Emmanuelle; Jourdain, Elsa; Hammed, Abdessalem; Fourel, Isabelle; Chikh, Farid; Vourc'h, Gwenaël

2017-01-01

Brown rats are one of the most widespread urban species worldwide. Despite the nuisances they induce and their potential role as a zoonotic reservoir, knowledge on urban rat populations remains scarce. The main purpose of this study was to characterize an urban brown rat population from Chanteraines park (Hauts-de-Seine, France), with regards to haematology, population genetics, immunogenic diversity, resistance to anticoagulant rodenticides, and community of parasites. Haematological parameters were measured. Population genetics was investigated using 13 unlinked microsatellite loci. Immunogenic diversity was assessed for Mhc-Drb. Frequency of the Y139F mutation (conferring resistance to rodenticides) and two linked microsatellites were studied, concurrently with the presence of anticoagulant residues in the liver. Combination of microscopy and molecular methods were used to investigate the occurrence of 25 parasites. Statistical approaches were used to explore multiple parasite relationships and model parasite occurrence. Eighty-six rats were caught. The first haematological data for a wild urban R. norvegicus population was reported. Genetic results suggested high genetic diversity and connectivity between Chanteraines rats and surrounding population(s). We found a high prevalence (55.8%) of the mutation Y139F and presence of rodenticide residues in 47.7% of the sampled individuals. The parasite species richness was high (16). Seven potential zoonotic pathogens were identified, together with a surprisingly high diversity of Leptospira species (4). Chanteraines rat population is not closed, allowing gene flow and making eradication programs challenging, particularly because rodenticide resistance is highly prevalent. Parasitological results showed that co-infection is more a rule than an exception. Furthermore, the presence of several potential zoonotic pathogens, of which four Leptospira species, in this urban rat population raised its role in the maintenance

The dominantly expressed class I molecule of the chicken MHC is explained by coevolution with the polymorphic peptide transporter (TAP) genes

DEFF Research Database (Denmark)

Walker, Brian A; Hunt, Lawrence G; Sowa, Anna K

2011-01-01

In most mammals, the MHC class I molecules are polymorphic and determine the specificity of peptide presentation, whereas the transporter associated with antigen presentation (TAP) heterodimers are functionally monomorphic. In chickens, there are two classical class I genes but only one is expres...

MHC class I molecules with superenhanced CD8 binding properties bypass the requirement for cognate TCR recognition and nonspecifically activate CTLs

NARCIS (Netherlands)

L. Wooldridge (Linda); M. Clement (Mathew); A. Lissina (Anna); E.S.J. Edwards (Emily); K. Ladell (Kristin); J. Ekeruche (Julia); R.E. Hewitt (Rachel); B. Laugel (Bruno); E. Gostick (Emma); D.K. Cole (David); J.E.M.A. Debets (Reno); C.A. Berrevoets (Cor); J.J. Miles (John); S.R. Burrows (Scott); D.A. Price (David); A.K. Sewell (Andrew)

2010-01-01

textabstractCD8+CTLs are essential for effective immune defense against intracellular microbes and neoplasia. CTLs recognize short peptide fragments presented in association with MHC class I (MHCI) molecules on the surface of infected or dysregulated cells. Ag recognition involves the binding of

Analysis of adrenocortical secretory responses during acute an prolonged immune stimulation in inflammation-susceptible and -resistant rat strains.

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Andersson, I M; Lorentzen, J C; Ericsson-Dahlstrand, A

2000-11-01

Endogenous corticosterone secreted during immune challenge restricts the inflammatory process and genetic variations in this neuroendocrine-immune dialogue have been suggested to influence an individuals sensitivity to develop chronic inflammatory disorders. We have tested inflammation-susceptible Dark Agouti (DA) rats and resistant, MHC-identical, PVG.1AV1 rats for their abilities to secrete corticosterone in response to acute challenge with bacterial lipopolysaccharide (LPS) or a prolonged activation of the nonspecific immune system with arthritogenic yeast beta-glucan. Intravenous injection of LPS triggered equipotent secretion of corticosterone in both rat strains. Interestingly, peak concentrations of corticosterone did not differ significantly between the strains. Intradermal injection of beta-glucan caused severe, monophasic, polyarthritis in DA rats while PVG.1AV1 responded with significantly milder joint inflammation. Importantly, serial sampling of plasma from glucan-injected DA and PVG.1AV1 rats did not reveal elevated concentrations of plasma corticosterone at any time from days 1-30 postinjection compared to preinjection values, in spite of the ongoing inflammatory process. Interestingly, adrenalectomized, beta-glucan-challenged DA rats responded with an aggravated arthritic process, indicating an anti-inflammatory role for the basal levels of corticosterone that were detected in intact DA rats challenged with beta-glucan. Moreover, substitution with subcutaneous corticosterone-secreting pellets, yielding moderate stress-levels, significantly attenuated the arthritic response. In contrast, adrenalectomized and glucan-challenged PVG.1AV1 rats did not respond with an elevated arthritic response, suggesting that these rats contain the arthritic process via corticosterone-independent mechanisms. In conclusion, the hypothalamic-pituitary-adrenal axis in both rat strains exhibited strong activation after challenge with LPS. This contrasted to the basal

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

MHC class I molecules (HLA-I in humans) present peptides derived from endogenous proteins to CTLs. Whereas the peptide-binding specificities of HLA-A and -B molecules have been studied extensively, little is known about HLA-C specificities. Combining a positional scanning combinatorial peptide...... 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...

5HT(4) agonists inhibit interferon-gamma-induced MHC class II and B7 costimulatory molecules expression on cultured astrocytes

NARCIS (Netherlands)

Zeinstra, Esther M.; Wilczak, Nadine; Wilschut, Jan C.; Glazenburg, Lisa; Chesik, Daniel; Kroese, Frans G. M.; De Keyser, Jacques

2006-01-01

A failure of tight control of MHC class II expression on astrocytes may play a role in the development of autoimmune responses in multiple sclerosis. The 5-HT4 serotonin receptor agonists cisapride and prucalopride, at concentrations between 10(-10) M and 10(-8) M, reduced interferon-gamma-induced

MHC class II expression through a hitherto unknown pathway supports T helper cell-dependent immune responses: implications for MHC class II deficiency.

Science.gov (United States)

Buch, Thorsten; Polic, Bojan; Clausen, Björn E; Weiss, Susanne; Akilli-Ozturk, Ozlem; Chang, Cheong-Hee; Flavell, Richard; Schulz, Ansgar; Jonjic, Stipan; Waisman, Ari; Förster, Irmgard

2006-02-15

MHC class II (MHCII) deficiency or bare lymphocyte syndrome (BLS) is a severe immunodeficiency characterized by deficient T helper (Th)-cell-dependent immunity. The disease is caused by defects of the MHCII promoter complex resulting in low or absent MHCII expression. We demonstrate in a murine model of MHCII deficiency (RFX5- or CIITA-deficient mice) that residual MHCII expression by professional antigen-presenting cells (APCs) is sufficient to support activation of adoptively transferred Th cells. Furthermore, upon transplantation of WT thymic epithelium, we observed development of endogenous Th cells with restoration of Th-cell-dependent antibody responses and immunity to cytomegalovirus infection, thus opening the possibility of an alternative treatment regimen for BLS. Residual MHCII expression was further induced by the presence of Th cells and also other stimuli. Analysis of CIITA/RFX5 double-deficient animals revealed that this inducible MHCII expression is genetically independent of the known promoter complex and thus constitutes an alternative MHCII expression pathway. In these experiments, we also detected a novel repressive function of the RFX complex in the absence of CIITA.

Blebbistain, a myosin II inhibitor, as a novel strategy to regulate detrusor contractility in a rat model of partial bladder outlet obstruction.

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Xinhua Zhang

Full Text Available Partial bladder outlet obstruction (PBOO, a common urologic pathology mostly caused by benign prostatic hyperplasia, can coexist in 40-45% of patients with overactive bladder (OAB and is associated with detrusor overactivity (DO. PBOO that induces DO results in alteration in bladder myosin II type and isoform composition. Blebbistatin (BLEB is a myosin II inhibitor we recently demonstrated potently relaxed normal detrusor smooth muscle (SM and reports suggest varied BLEB efficacy for different SM myosin (SMM isoforms and/or SMM vs nonmuscle myosin (NMM. We hypothesize BLEB inhibition of myosin II as a novel contraction protein targeted strategy to regulate DO. Using a surgically-induced male rat PBOO model, organ bath contractility, competitive and Real-Time-RT-PCR were performed. It was found that obstructed-bladder weight significantly increased 2.74-fold while in vitro contractility of detrusor to various stimuli was impaired ∼50% along with decreased shortening velocity. Obstruction also altered detrusor spontaneous activities with significantly increased amplitude but depressed frequency. PBOO switched bladder from a phasic-type to a more tonic-type SM. Expression of 5' myosin heavy chain (MHC alternatively spliced isoform SM-A (associated with tonic-type SM increased 3-fold while 3' MHC SM1 and essential light chain isoform MLC(17b also exhibited increased relative expression. Total SMMHC expression was decreased by 25% while the expression of NMM IIB (SMemb was greatly increased by 4.5-fold. BLEB was found to completely relax detrusor strips from both sham-operated and PBOO rats pre-contracted with KCl, carbachol or electrical field stimulation although sensitivity was slightly decreased (20% only at lower doses for PBOO. Thus we provide the first thorough characterization of the response of rat bladder myosin to PBOO and demonstrate complete BLEB-induced PBOO bladder SM relaxation. Furthermore, the present study provides valuable

Testing genotyping strategies for ultra-deep sequencing of a co-amplifying gene family: MHC class I in a passerine bird.

Science.gov (United States)

Biedrzycka, Aleksandra; Sebastian, Alvaro; Migalska, Magdalena; Westerdahl, Helena; Radwan, Jacek

2017-07-01

Characterization of highly duplicated genes, such as genes of the major histocompatibility complex (MHC), where multiple loci often co-amplify, has until recently been hindered by insufficient read depths per amplicon. Here, we used ultra-deep Illumina sequencing to resolve genotypes at exon 3 of MHC class I genes in the sedge warbler (Acrocephalus schoenobaenus). We sequenced 24 individuals in two replicates and used this data, as well as a simulated data set, to test the effect of amplicon coverage (range: 500-20 000 reads per amplicon) on the repeatability of genotyping using four different genotyping approaches. A third replicate employed unique barcoding to assess the extent of tag jumping, that is swapping of individual tag identifiers, which may confound genotyping. The reliability of MHC genotyping increased with coverage and approached or exceeded 90% within-method repeatability of allele calling at coverages of >5000 reads per amplicon. We found generally high agreement between genotyping methods, especially at high coverages. High reliability of the tested genotyping approaches was further supported by our analysis of the simulated data set, although the genotyping approach relying primarily on replication of variants in independent amplicons proved sensitive to repeatable errors. According to the most repeatable genotyping method, the number of co-amplifying variants per individual ranged from 19 to 42. Tag jumping was detectable, but at such low frequencies that it did not affect the reliability of genotyping. We thus demonstrate that gene families with many co-amplifying genes can be reliably genotyped using HTS, provided that there is sufficient per amplicon coverage. © 2016 John Wiley & Sons Ltd.

Normalized Synergy Predicts That CD8 Co-Receptor Contribution to T Cell Receptor (TCR and pMHC Binding Decreases As TCR Affinity Increases in Human Viral-Specific T Cells

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