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Sample records for cd8 t-cell epitopes

  1. Novel CD8(+) cytotoxic T cell epitopes in bovine leukemia virus with cattle.

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    Bai, Lanlan; Takeshima, Shin-Nosuke; Isogai, Emiko; Kohara, Junko; Aida, Yoko

    2015-12-16

    Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis and is closely related to human T cell leukemia virus (HTLV). The cytotoxic T lymphocyte (CTL) plays a key role in suppressing the progression of disease caused by BLV. T and B cell epitopes in BLV have been studied, but CD8(+) CTL epitopes remain poorly understood. We used a library of 115 synthetic peptides covering the entirety of the Env proteins (gp51 and gp30), the Gag proteins (p15, p24, and p12), and the Tax protein of BLV to identify 11 novel CD8(+) T cell epitopes (gp51N5, gp51N11, gp51N12, gp30N5, gp30N6, gp30N8, gp30N16, tax16, tax18, tax19, and tax20) in four calves experimentally infected with BLV. The number of CD8(+) T cell epitopes that could be identified in each calf correlated with the BLV proviral load. Interestingly, among the 11 epitopes identified, only gp51N11 was capable of inducing CD8(+) T cell-mediated cytotoxicity in all four calves, but it is not a suitable vaccine target because it shows a high degree of polymorphism according to the Wu-Kabat variability index. By contrast, no CTL epitopes were identified from the Gag structural protein. In addition, several epitopes were obtained from gp30 and Tax, indicating that cellular immunity against BLV is strongly targeted to these proteins. CD8(+) CTL epitopes from gp30 and Tax were less polymorphic than epitopes from. Indeed, peptides tax16, tax18, tax19, and tax20 include a leucine-rich activation domain that encompasses a transcriptional activation domain, and the gp30N16 peptide contains a proline-rich region that interacts with a protein tyrosine phosphatase SHP1 to regulate B cell activation. Moreover, at least one CD8(+) CTL epitope derived from gp30 was identified in each of the four calves. These results indicate that BLV gp30 may be the best candidate for the development of a BLV vaccine. PMID:26552001

  2. Novel CD8(+) cytotoxic T cell epitopes in bovine leukemia virus with cattle.

    Science.gov (United States)

    Bai, Lanlan; Takeshima, Shin-Nosuke; Isogai, Emiko; Kohara, Junko; Aida, Yoko

    2015-12-16

    Bovine leukemia virus (BLV) is associated with enzootic bovine leukosis and is closely related to human T cell leukemia virus (HTLV). The cytotoxic T lymphocyte (CTL) plays a key role in suppressing the progression of disease caused by BLV. T and B cell epitopes in BLV have been studied, but CD8(+) CTL epitopes remain poorly understood. We used a library of 115 synthetic peptides covering the entirety of the Env proteins (gp51 and gp30), the Gag proteins (p15, p24, and p12), and the Tax protein of BLV to identify 11 novel CD8(+) T cell epitopes (gp51N5, gp51N11, gp51N12, gp30N5, gp30N6, gp30N8, gp30N16, tax16, tax18, tax19, and tax20) in four calves experimentally infected with BLV. The number of CD8(+) T cell epitopes that could be identified in each calf correlated with the BLV proviral load. Interestingly, among the 11 epitopes identified, only gp51N11 was capable of inducing CD8(+) T cell-mediated cytotoxicity in all four calves, but it is not a suitable vaccine target because it shows a high degree of polymorphism according to the Wu-Kabat variability index. By contrast, no CTL epitopes were identified from the Gag structural protein. In addition, several epitopes were obtained from gp30 and Tax, indicating that cellular immunity against BLV is strongly targeted to these proteins. CD8(+) CTL epitopes from gp30 and Tax were less polymorphic than epitopes from. Indeed, peptides tax16, tax18, tax19, and tax20 include a leucine-rich activation domain that encompasses a transcriptional activation domain, and the gp30N16 peptide contains a proline-rich region that interacts with a protein tyrosine phosphatase SHP1 to regulate B cell activation. Moreover, at least one CD8(+) CTL epitope derived from gp30 was identified in each of the four calves. These results indicate that BLV gp30 may be the best candidate for the development of a BLV vaccine.

  3. Human CD8(+) T Cells Target Multiple Epitopes in Respiratory Syncytial Virus Polymerase.

    Science.gov (United States)

    Burbulla, Daniel; Günther, Patrick S; Peper, Janet K; Jahn, Gerhard; Dennehy, Kevin M

    2016-06-01

    Respiratory syncytial virus (RSV) infection is a serious health problem in young children, immunocompromised patients, and the elderly. The development of novel prevention strategies, such as a vaccine to RSV, is a high priority. One strategy is to design a peptide-based vaccine that activates appropriate CD8(+) T-cell responses. However, this approach is limited by the low number of RSV peptide epitopes defined to date that activate CD8(+) T cells. We aimed to identify peptide epitopes that are presented by common human leukocyte antigen types (HLA-A*01, -A*02, and -B*07). We identify one novel HLA-A*02-restricted and two novel HLA-A*01-restricted peptide epitopes from RSV polymerase. Peptide-HLA multimer staining of specific T cells from healthy donor peripheral blood mononuclear cell, the memory phenotype of such peptide-specific T cells ex vivo, and functional IFNγ responses in short-term stimulation assays suggest that these peptides are recognized during RSV infection. Such peptides are candidates for inclusion into a peptide-based RSV vaccine designed to stimulate defined CD8(+) T-cell responses.

  4. Chemical Modification of Influenza CD8+ T-Cell Epitopes Enhances Their Immunogenicity Regardless of Immunodominance

    Science.gov (United States)

    van Beek, Josine; Hoppes, Rieuwert; Jacobi, Ronald H. J.; Hendriks, Marion; Kapteijn, Kim; Ouwerkerk, Casper; Rodenko, Boris; Ovaa, Huib; de Jonge, Jørgen

    2016-01-01

    T cells are essential players in the defense against infection. By targeting the MHC class I antigen-presenting pathway with peptide-based vaccines, antigen-specific T cells can be induced. However, low immunogenicity of peptides poses a challenge. Here, we set out to increase immunogenicity of influenza-specific CD8+ T cell epitopes. By substituting amino acids in wild type sequences with non-proteogenic amino acids, affinity for MHC can be increased, which may ultimately enhance cytotoxic CD8+ T cell responses. Since preventive vaccines against viruses should induce a broad immune response, we used this method to optimize influenza-specific epitopes of varying dominance. For this purpose, HLA-A*0201 epitopes GILGFVFTL, FMYSDFHFI and NMLSTVLGV were selected in order of decreasing MHC-affinity and dominance. For all epitopes, we designed chemically enhanced altered peptide ligands (CPLs) that exhibited greater binding affinity than their WT counterparts; even binding scores of the high affinity GILGFVFTL epitope could be improved. When HLA-A*0201 transgenic mice were vaccinated with selected CPLs, at least 2 out of 4 CPLs of each epitope showed an increase in IFN-γ responses of splenocytes. Moreover, modification of the low affinity epitope NMLSTVLGV led to an increase in the number of mice that responded. By optimizing three additional influenza epitopes specific for HLA-A*0301, we show that this strategy can be extended to other alleles. Thus, enhancing binding affinity of peptides provides a valuable tool to improve the immunogenicity and range of preventive T cell-targeted peptide vaccines. PMID:27333291

  5. Viral Escape Mutant Epitope Maintains TCR Affinity for Antigen yet Curtails CD8 T Cell Responses.

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    Shayla K Shorter

    Full Text Available T cells have the remarkable ability to recognize antigen with great specificity and in turn mount an appropriate and robust immune response. Critical to this process is the initial T cell antigen recognition and subsequent signal transduction events. This antigen recognition can be modulated at the site of TCR interaction with peptide:major histocompatibility (pMHC or peptide interaction with the MHC molecule. Both events could have a range of effects on T cell fate. Though responses to antigens that bind sub-optimally to TCR, known as altered peptide ligands (APL, have been studied extensively, the impact of disrupting antigen binding to MHC has been highlighted to a lesser extent and is usually considered to result in complete loss of epitope recognition. Here we present a model of viral evasion from CD8 T cell immuno-surveillance by a lymphocytic choriomeningitis virus (LCMV escape mutant with an epitope for which TCR affinity for pMHC remains high but where the antigenic peptide binds sub optimally to MHC. Despite high TCR affinity for variant epitope, levels of interferon regulatory factor-4 (IRF4 are not sustained in response to the variant indicating differences in perceived TCR signal strength. The CD8+ T cell response to the variant epitope is characterized by early proliferation and up-regulation of activation markers. Interestingly, this response is not maintained and is characterized by a lack in IL-2 and IFNγ production, increased apoptosis and an abrogated glycolytic response. We show that disrupting the stability of peptide in MHC can effectively disrupt TCR signal strength despite unchanged affinity for TCR and can significantly impact the CD8+ T cell response to a viral escape mutant.

  6. Dengue virus specific dual HLA binding T cell epitopes induce CD8+ T cell responses in seropositive individuals.

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    Comber, Joseph D; Karabudak, Aykan; Huang, Xiaofang; Piazza, Paolo A; Marques, Ernesto T A; Philip, Ramila

    2014-01-01

    Dengue virus infects an estimated 300 million people each year and even more are at risk of becoming infected as the virus continues to spread into new areas. Despite the increase in viral prevalence, no anti-viral medications or vaccines are approved for treating or preventing infection. CD8+ T cell responses play a major role in viral clearance. Therefore, effective vaccines that induce a broad, multi-functional T cell response with substantial cross-reactivity between all virus serotypes can have major impacts on reducing infection rates and infection related complications. Here, we took an immunoproteomic approach to identify novel MHC class I restricted T cell epitopes presented by dengue virus infected cells, representing the natural and authentic targets of the T cell response. Using this approach we identified 4 novel MHC-I restricted epitopes: 2 with the binding motif for HLA-A24 molecules and 2 with both HLA-A2 and HLA-A24 binding motifs. These peptides were able to activate CD8+ T cell responses in both healthy, seronegative individuals and in seropositive individuals who have previously been infected with dengue virus. Importantly, the dual binding epitopes activated pre-existing T cell precursors in PBMCs obtained from both HLA-A2+ and HLA-A24+ seropositive individuals. Together, the data indicate that these epitopes are immunologically relevant T cell activating peptides presented on infected cells during a natural infection and therefore may serve as candidate antigens for the development of effective multi-serotype specific dengue virus vaccines. PMID:25668665

  7. Superior control of HIV-1 replication by CD8+ T cells targeting conserved epitopes: implications for HIV vaccine design.

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    Pratima Kunwar

    Full Text Available A successful HIV vaccine will likely induce both humoral and cell-mediated immunity, however, the enormous diversity of HIV has hampered the development of a vaccine that effectively elicits both arms of the adaptive immune response. To tackle the problem of viral diversity, T cell-based vaccine approaches have focused on two main strategies (i increasing the breadth of vaccine-induced responses or (ii increasing vaccine-induced responses targeting only conserved regions of the virus. The relative extent to which set-point viremia is impacted by epitope-conservation of CD8(+ T cell responses elicited during early HIV-infection is unknown but has important implications for vaccine design. To address this question, we comprehensively mapped HIV-1 CD8(+ T cell epitope-specificities in 23 ART-naïve individuals during early infection and computed their conservation score (CS by three different methods (prevalence, entropy and conseq on clade-B and group-M sequence alignments. The majority of CD8(+ T cell responses were directed against variable epitopes (p<0.01. Interestingly, increasing breadth of CD8(+ T cell responses specifically recognizing conserved epitopes was associated with lower set-point viremia (r = - 0.65, p = 0.009. Moreover, subjects possessing CD8(+ T cells recognizing at least one conserved epitope had 1.4 log10 lower set-point viremia compared to those recognizing only variable epitopes (p = 0.021. The association between viral control and the breadth of conserved CD8(+ T cell responses may be influenced by the method of CS definition and sequences used to determine conservation levels. Strikingly, targeting variable versus conserved epitopes was independent of HLA type (p = 0.215. The associations with viral control were independent of functional avidity of CD8(+ T cell responses elicited during early infection. Taken together, these data suggest that the next-generation of T-cell based HIV-1 vaccines should focus

  8. Programmed death-1 expression on HIV-1-specific CD8+ T cells is shaped by epitope specificity, T-cell receptor clonotype usage and antigen load

    DEFF Research Database (Denmark)

    Kløverpris, Henrik N; McGregor, Reuben; McLaren, James E;

    2014-01-01

    ) clonotypes within individual HIV-1-specific CD8+ T-cell populations was also apparent, independent of clonal dominance hierarchies. Positive correlations were detected between PD-1 expression and plasma viral load, which were reinforced by stratification for epitope sequence stability and dictated...... by effector memory CD8+ T cells. CONCLUSION: Collectively, these data suggest that PD-1 expression on HIV-1-specific CD8+ T cells tracks antigen load at the level of epitope specificity and TCR clonotype usage. These findings are important because they provide evidence that PD-1 expression levels......OBJECTIVES: Although CD8+ T cells play a critical role in the control of HIV-1 infection,their antiviral efficacy can be limited by antigenic variation and immune exhaustion.The latter phenomenon is characterized by the upregulation of multiple inhibitory receptors, such as programmed death-1 (PD-1...

  9. Identification of Candidate Tolerogenic CD8+ T Cell Epitopes for Therapy of Type 1 Diabetes in the NOD Mouse Model

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    Cailin Yu

    2016-01-01

    Full Text Available Type 1 diabetes is an autoimmune disease in which insulin-producing pancreatic islet β cells are the target of self-reactive B and T cells. T cells reactive with epitopes derived from insulin and/or IGRP are critical for the initiation and maintenance of disease, but T cells reactive with other islet antigens likely have an essential role in disease progression. We sought to identify candidate CD8+ T cell epitopes that are pathogenic in type 1 diabetes. Proteins that elicit autoantibodies in human type 1 diabetes were analyzed by predictive algorithms for candidate epitopes. Using several different tolerizing regimes using synthetic peptides, two new predicted tolerogenic CD8+ T cell epitopes were identified in the murine homolog of the major human islet autoantigen zinc transporter ZnT8 (aa 158–166 and 282–290 and one in a non-β cell protein, dopamine β-hydroxylase (aa 233–241. Tolerizing vaccination of NOD mice with a cDNA plasmid expressing full-length proinsulin prevented diabetes, whereas plasmids encoding ZnT8 and DβH did not. However, tolerizing vaccination of NOD mice with the proinsulin plasmid in combination with plasmids expressing ZnT8 and DβH decreased insulitis and enhanced prevention of disease compared to vaccination with the plasmid encoding proinsulin alone.

  10. Identification of Candidate Tolerogenic CD8+ T Cell Epitopes for Therapy of Type 1 Diabetes in the NOD Mouse Model

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    Yu, Cailin; Burns, Jeremy C.; Robinson, William H.; Utz, Paul J.; Ho, Peggy P.; Steinman, Lawrence; Frey, Alan B.

    2016-01-01

    Type 1 diabetes is an autoimmune disease in which insulin-producing pancreatic islet β cells are the target of self-reactive B and T cells. T cells reactive with epitopes derived from insulin and/or IGRP are critical for the initiation and maintenance of disease, but T cells reactive with other islet antigens likely have an essential role in disease progression. We sought to identify candidate CD8+ T cell epitopes that are pathogenic in type 1 diabetes. Proteins that elicit autoantibodies in human type 1 diabetes were analyzed by predictive algorithms for candidate epitopes. Using several different tolerizing regimes using synthetic peptides, two new predicted tolerogenic CD8+ T cell epitopes were identified in the murine homolog of the major human islet autoantigen zinc transporter ZnT8 (aa 158–166 and 282–290) and one in a non-β cell protein, dopamine β-hydroxylase (aa 233–241). Tolerizing vaccination of NOD mice with a cDNA plasmid expressing full-length proinsulin prevented diabetes, whereas plasmids encoding ZnT8 and DβH did not. However, tolerizing vaccination of NOD mice with the proinsulin plasmid in combination with plasmids expressing ZnT8 and DβH decreased insulitis and enhanced prevention of disease compared to vaccination with the plasmid encoding proinsulin alone. PMID:27069933

  11. Phase I Trial of a CD8+ T-Cell Peptide Epitope-Based Vaccine for Infectious Mononucleosis▿

    OpenAIRE

    Elliott, Suzanne L.; Suhrbier, Andreas; Miles, John J.; Lawrence, Greg; Pye, Stephanie J.; Le, Thuy T.; Rosenstengel, Andrew; Nguyen, Tam; Allworth, Anthony; Burrows, Scott R.; COX, JOHN; Pye, David; Moss, Denis J.; Bharadwaj, Mandvi

    2007-01-01

    A single blind, randomized, placebo-controlled, single-center phase I clinical trial of a CD8+ T-cell peptide epitope vaccine against infectious mononucleosis was conducted with 14 HLA B*0801-positive, Epstein-Barr virus (EBV)-seronegative adults. The vaccine comprised the HLA B*0801-restricted peptide epitope FLRGRAYGL and tetanus toxoid formulated in a water-in-oil adjuvant, Montanide ISA 720. FLRGRAYGL-specific responses were detected in 8/9 peptide-vaccine recipients and 0/4 placebo vacci...

  12. Generation of functional CD8+ T Cells by human dendritic cells expressing glypican-3 epitopes

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    Farzaneh Farzin

    2010-05-01

    Full Text Available Abstract Background Glypican 3 (GPC-3 is an oncofoetal protein that is expressed in most hepatocellular carcinomas (HCC. Since it is a potential target for T cell immunotherapy, we investigated the generation of functional, GPC-3 specific T cells from peripheral blood mononuclear cells (PBMC. Methods Dendritic cells (DC were derived from adherent PBMC cultured at 37°C for 7 days in X-Vivo, 1% autologous plasma, and 800 u/ml GM-CSF plus 500 u/ml IL-4. Immature DC were transfected with 20 μg of in vitro synthesised GPC-3 mRNA by electroporation using the Easy-ject plus system (Equibio, UK (300 V, 150 μF and 4 ms pulse time, or pulsed with peptide, and subsequently matured with lipopolysaccharide (LPS. Six predicted GPC-3 peptide epitopes were synthesized using standard f-moc technology and tested for their binding affinity to HLA-A2.1 molecules using the cell line T2. Results DC transfected with GPC-3 mRNA but not control DC demonstrated strong intracellular staining for GPC-3 and in vitro generated interferon-gamma expressing T cells from autologous PBMC harvested from normal subjects. One peptide, GPC-3522-530 FLAELAYDL, fulfilled our criteria as a naturally processed, HLA-A2-restricted cytotoxic T lymphocyte (CTL epitope: i it showed high affinity binding to HLA-A2, in T2 cell binding assay; ii it was generated by the MHC class I processing pathway in DC transfected with GPC-3 mRNA, and iii HLA-A2 positive DC loaded with the peptide stimulated proliferation in autologous T cells and generated CTL that lysed HLA-A2 and GPC-3 positive target cells. Conclusions These findings demonstrate that electroporation of GPC-3 mRNA is an efficient method to load human monocyte-derived DC with antigen because in vitro they generated GPC-3-reactive T cells that were functional, as shown by interferon-gamma production. Furthermore, this study identified a novel naturally processed, HLA-A2-restricted CTL epitope, GPC-3522-530 FLAELAYDL, which can be used to

  13. Rapid Antigen Processing and Presentation of a Protective and Immunodominant HLA-B*27-restricted Hepatitis C Virus-specific CD8+ T-cell Epitope

    OpenAIRE

    Julia Schmidt; Iversen, Astrid K N; Stefan Tenzer; Emma Gostick; Price, David A.; Volker Lohmann; Ute Distler; Paul Bowness; Hansjörg Schild; Blum, Hubert E.; Paul Klenerman; Christoph Neumann-Haefelin; Robert Thimme

    2012-01-01

    HLA-B*27 exerts protective effects in hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections. While the immunological and virological features of HLA-B*27-mediated protection are not fully understood, there is growing evidence that the presentation of specific immunodominant HLA-B*27-restricted CD8+ T-cell epitopes contributes to this phenomenon in both infections. Indeed, protection can be linked to single immunodominant CD8+ T-cell epitopes and functional constraints on e...

  14. Single-epitope DNA vaccination prevents exhaustion and facilitates a broad antiviral CD8+ T cell response during chronic viral infection

    DEFF Research Database (Denmark)

    Bartholdy, Christina; Stryhn, Anette; Christensen, Jan Pravsgaard;

    2004-01-01

    of DNA vaccines encoding immunodominant epitopes of lymphocytic choriomeningitis virus (LCMV). We analyzed the spectrum of the CD8+ T cell response and the susceptibility to infection in H-2(b) and H-2(d) mice. Priming for a monospecific, CD8+ T cell response did not render mice susceptible to viral...... variants. Thus, vaccinated mice were protected against chronic infection with LCMV, and no evidence indicating biologically relevant viral escape was obtained. In parallel, a broad and sustained CD8+ T cell response was generated upon infection, and in H-2(d) mice epitope spreading was observed. Even after...... acute LCMV infection, DNA vaccination did not significantly impair naturally induced immunity. Thus, the response to the other immunogenic epitopes was not dramatically suppressed in DNA-immunized mice undergoing normal immunizing infection, and the majority of mice were protected against rechallenge...

  15. Elimination of immunodominant epitopes from multispecific DNA-based vaccines allows induction of CD8 T cells that have a striking antiviral potential

    DEFF Research Database (Denmark)

    Riedl, Petra; Wieland, Andreas; Lamberth, Kasper;

    2009-01-01

    Immunodominance limits the TCR diversity of specific antiviral CD8 T cell responses elicited by vaccination or infection. To prime multispecific T cell responses, we constructed DNA vaccines that coexpress chimeric, multidomain Ags (with CD8 T cell-defined epitopes of the hepatitis B virus (HBV......) surface (S), core (C), and polymerase (Pol) proteins and/or the OVA Ag as stress protein-capturing fusion proteins. Priming of mono- or multispecific, HLA-A*0201- or K(b)-restricted CD8 T cell responses by these DNA vaccines differed. K(b)/OVA(257-264)- and K(b)/S(190-197)-specific CD8 T cell responses...... did not allow priming of a K(b)/C(93-100)-specific CD8 T cell response in mice immunized with multidomain vaccines. Tolerance to the S- Ag in transgenic Alb/HBs mice (that express large amounts of transgene-encoded S- Ag in the liver) facilitated priming of subdominant, K(b)/C(93-100)-specific CD8 T...

  16. Vaccination for 2009 pandemic H1N1 influenza A did not induce conserved epitope-specific memory CD8 T cell responses in HIV+ northern Thai children.

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    Chawansuntati, Kriangkrai; Aurpibul, Linda; Wipasa, Jiraprapa

    2015-09-11

    The influenza virus causes severe illness in susceptible populations, including children and people living with human immunodeficiency virus (HIV). Here, we investigated cell-mediated immune responses (CMI) against influenza CD8 T cell conserved epitopes in HIV-infected (HIV+) northern Thai children following the 2009 pandemic H1N1 influenza A vaccination. Sixty HIV+ children were vaccinated with two doses of the 2009 pandemic influenza vaccine and their CD8T cell responses were assessed. We found no significant differences in the increase of cytokines-producing and CD107a-expressing CD8+ T cells or CD8+ memory T cells in response to pooled conserved epitopes stimulation in vitro between children with different serologic responses to the vaccine at all time points of the study. Our results suggest that the 2009 pandemic H1N1 vaccine did not induce the conserved epitope-specific immune responses in HIV+ children. Vaccine design and vaccination strategy against influenza in these populations warrant further studies.

  17. Strategy for eliciting antigen-specific CD8+ T cell-mediated immune response against a cryptic CTL epitope of merkel cell polyomavirus large T antigen

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    Gomez Bianca P

    2012-10-01

    Full Text Available Abstract Background Merkel cell carcinoma (MCC is a relatively new addition to the expanding category of oncovirus-induced cancers. Although still comparably rare, the number of cases has risen dramatically in recent years. Further complicating this trend is that MCC is an extremely aggressive neoplasm with poor patient prognosis and limited treatment options for advanced disease. The causative agent of MCC has been identified as the merkel cell polyomavirus (MCPyV. The MCPyV-encoded large T (LT antigen is an oncoprotein that is theorized to be essential for virus-mediated tumorigenesis and is therefore, an excellent MCC antigen for the generation of antitumor immune responses. As a foreign antigen, the LT oncoprotein avoids the obstacle of immune tolerance, which normally impedes the development of antitumor immunity. Ergo, it is an excellent target for anti-MCC immunotherapy. Since tumor-specific CD8+ T cells lead to better prognosis for MCC and numerous other cancers, we have generated a DNA vaccine that is capable of eliciting LT-specific CD8+ T cells. The DNA vaccine (pcDNA3-CRT/LT encodes the LT antigen linked to a damage-associated molecular pattern, calreticulin (CRT, as it has been demonstrated that the linkage of CRT to antigens promotes the induction of antigen-specific CD8+ T cells. Results The present study shows that DNA vaccine-induced generation of LT-specific CD8+ T cells is augmented by linking CRT to the LT antigen. This is relevant since the therapeutic effects of the pcDNA3-CRT/LT DNA vaccine is mediated by LT-specific CD8+ T cells. Mice vaccinated with the DNA vaccine produced demonstrably more LT-specific CD8+ T cells. The DNA vaccine was also able to confer LT-specific CD8+ T cell-mediated protective and therapeutic effects to prolong the survival of mice with LT-expressing tumors. In the interest of determining the LT epitope which most MCC-specific CD8+ T cells recognize, we identified the amino acid sequence of the

  18. Identification of conserved subdominant HIV Type 1 CD8(+) T Cell epitopes restricted within common HLA Supertypes for therapeutic HIV Type 1 vaccines

    DEFF Research Database (Denmark)

    Karlsson, Ingrid; Kløverpris, Henrik; Jensen, Kristoffer Jarlov;

    2012-01-01

    of a universal epitope peptide-based T cell vaccine with relevance for any geographic locations. The two major obstacles when designing such a vaccine are the high diversities of the HIV-1 genome and of the human major histocompatibility complex (MHC) class I. We selected 15 CD8-restricted epitopes predicted...... from conserved regions of HIV-1 that were subdominant (i.e., infrequently targeted) within natural infections. Moreover, the epitopes were predicted to be restricted to at least one of the five common HLA supertypes (HLA-A01, A02, A03, B07, and B44). Here, we validated the resulting peptide...

  19. A missing PD-L1/PD-1 coinhibition regulates diabetes induction by preproinsulin-specific CD8 T-cells in an epitope-specific manner.

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    Cornelia Schuster

    Full Text Available Coinhibitory PD-1/PD-L1 (B7-H1 interactions provide critical signals for the regulation of autoreactive T-cell responses. We established mouse models, expressing the costimulator molecule B7.1 (CD80 on pancreatic beta cells (RIP-B7.1 tg mice or are deficient in coinhibitory PD-L1 or PD-1 molecules (PD-L1(-/- and PD-1(-/- mice, to study induction of preproinsulin (ppins-specific CD8 T-cell responses and experimental autoimmune diabetes (EAD by DNA-based immunization. RIP-B7.1 tg mice allowed us to identify two CD8 T-cell specificities: pCI/ppins DNA exclusively induced K(b/A(12-21-specific CD8 T-cells and EAD, whereas pCI/ppinsΔA(12-21 DNA (encoding ppins without the COOH-terminal A(12-21 epitope elicited K(b/B(22-29-specific CD8 T-cells and EAD. Specific expression/processing of mutant ppinsΔA(12-21 (but not ppins in non-beta cells, targeted by intramuscular DNA-injection, thus facilitated induction of K(b/B(22-29-specific CD8 T-cells. The A(12-21 epitope binds K(b molecules with a very low avidity as compared with B(22-29. Interestingly, immunization of coinhibition-deficient PD-L1(-/- or PD-1(-/- mice with pCI/ppins induced K(b/A(12-21-monospecific CD8 T-cells and EAD but injections with pCI/ppinsΔA(12-21 did neither recruit K(b/B(22-29-specific CD8 T-cells into the pancreatic target tissue nor induce EAD. PpinsΔA(12-21/(K(b/B(22-29-mediated EAD was efficiently restored in RIP-B7.1(+/PD-L1(-/- mice, differing from PD-L1(-/- mice only in the tg B7.1 expression in beta cells. Alternatively, an ongoing beta cell destruction and tissue inflammation, initiated by ppins/(K(b/A(12-21-specific CD8 T-cells in pCI/ppins+pCI/ppinsΔA(12-21 co-immunized PD-L1(-/- mice, facilitated the expansion of ppinsΔA(12-21/(K(b/B(22-29-specific CD8 T-cells. CD8 T-cells specific for the high-affinity K(b/B(22-29- (but not the low-affinity K(b/A(12-21-epitope thus require stimulatory help from beta cells or inflamed islets to expand in PD-L1-deficient mice. The

  20. The generation of CD8+ T-cell population specific for vaccinia virus epitope involved in the antiviral protection against ectromelia virus challenge.

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    Gierynska, Malgorzata; Szulc-Dabrowska, Lidia; Dzieciatkowski, Tomasz; Golke, Anna; Schollenberger, Ada

    2015-12-01

    Eradication of smallpox has led to cessation of vaccination programs. This has rendered the human population increasingly susceptible not only to variola virus infection but also to infections with other representatives of Poxviridae family that cause zoonotic variola-like diseases. Thus, new approaches for designing improved vaccine against smallpox are required. Discovering that orthopoxviruses, e.g. variola virus, vaccinia virus, ectromelia virus, share common immunodominant antigen, may result in the development of such a vaccine. In our study, the generation of antigen-specific CD8(+) T cells in mice during the acute and memory phase of the immune response was induced using the vaccinia virus immunodominant TSYKFESV epitope and CpG oligodeoxynucleotides as adjuvants. The role of the generated TSYKFESV-specific CD8(+) T cells was evaluated in mice during ectromelia virus infection using systemic and mucosal model. Moreover, the involvement of dendritic cells subsets in the adaptive immune response stimulation was assessed. Our results indicate that the TSYKFESV epitope/TLR9 agonist approach, delivered systemically or mucosally, generated strong CD8(+) T-cell response when measured 10 days after immunization. Furthermore, the TSYKFESV-specific cell population remained functionally active 2 months post-immunization, and gave cross-protection in virally challenged mice, even though the numbers of detectable antigen-specific T cells decreased. PMID:26474845

  1. CD8(+) T-cell Cytotoxic Capacity Associated with Human Immunodeficiency Virus-1 Control Can Be Mediated through Various Epitopes and Human Leukocyte Antigen Types.

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    Migueles, Stephen A; Mendoza, Daniel; Zimmerman, Matthew G; Martins, Kelly M; Toulmin, Sushila A; Kelly, Elizabeth P; Peterson, Bennett A; Johnson, Sarah A; Galson, Eric; Poropatich, Kate O; Patamawenu, Andy; Imamichi, Hiromi; Ober, Alexander; Rehm, Catherine A; Jones, Sara; Hallahan, Claire W; Follmann, Dean A; Connors, Mark

    2015-01-01

    Understanding natural immunologic control over Human Immunodeficiency Virus (HIV)-1 replication, as occurs in rare long-term nonprogressors/elite controllers (LTNP/EC), should inform the design of efficacious HIV vaccines and immunotherapies. Durable control in LTNP/EC is likely mediated by highly functional virus-specific CD8(+) T-cells. Protective Human Leukocyte Antigen (HLA) class I alleles, like B*27 and B*57, are present in most, but not all LTNP/EC, providing an opportunity to investigate features shared by their HIV-specific immune responses. To better understand the contribution of epitope targeting and conservation to immune control, we compared the CD8(+) T-cell specificity and function of B*27/57(neg) LTNP/EC (n = 23), B*27/57(pos) LTNP/EC (n = 23) and B*27/57(neg) progressors (n = 13). Fine mapping revealed 11 previously unreported immunodominant responses. Although B*27/57(neg) LTNP/EC did not target more highly conserved epitopes, their CD8(+) T-cell cytotoxic capacity was significantly higher than progressors. Similar to B*27/57(pos) LTNP/EC, this superior cytotoxicity was mediated by preferential expansion of immunodominant responses and lysis through the predicted HLA. These findings suggest that increased CD8(+) T-cell cytotoxic capacity is a common mechanism of control in most LTNP/EC regardless of HLA type. They also suggest that potent cytotoxicity can be mediated through various epitopes and HLA molecules and could, in theory, be induced in most people. PMID:26137533

  2. CD8+ T-cell Cytotoxic Capacity Associated with Human Immunodeficiency Virus-1 Control Can Be Mediated through Various Epitopes and Human Leukocyte Antigen Types

    Directory of Open Access Journals (Sweden)

    Stephen A. Migueles

    2015-01-01

    Full Text Available Understanding natural immunologic control over Human Immunodeficiency Virus (HIV-1 replication, as occurs in rare long-term nonprogressors/elite controllers (LTNP/EC, should inform the design of efficacious HIV vaccines and immunotherapies. Durable control in LTNP/EC is likely mediated by highly functional virus-specific CD8+ T-cells. Protective Human Leukocyte Antigen (HLA class I alleles, like B*27 and B*57, are present in most, but not all LTNP/EC, providing an opportunity to investigate features shared by their HIV-specific immune responses. To better understand the contribution of epitope targeting and conservation to immune control, we compared the CD8+ T-cell specificity and function of B*27/57neg LTNP/EC (n = 23, B*27/57pos LTNP/EC (n = 23 and B*27/57neg progressors (n = 13. Fine mapping revealed 11 previously unreported immunodominant responses. Although B*27/57neg LTNP/EC did not target more highly conserved epitopes, their CD8+ T-cell cytotoxic capacity was significantly higher than progressors. Similar to B*27/57pos LTNP/EC, this superior cytotoxicity was mediated by preferential expansion of immunodominant responses and lysis through the predicted HLA. These findings suggest that increased CD8+ T-cell cytotoxic capacity is a common mechanism of control in most LTNP/EC regardless of HLA type. They also suggest that potent cytotoxicity can be mediated through various epitopes and HLA molecules and could, in theory, be induced in most people.

  3. Differential presentation of endogenous and exogenous hepatitis B surface antigens influences priming of CD8(+) T cells in an epitope-specific manner.

    Science.gov (United States)

    Riedl, Petra; Reiser, Michael; Stifter, Katja; Krieger, Jana; Schirmbeck, Reinhold

    2014-07-01

    Little is known about whether presentation of endogenous and exogenous hepatitis B virus (HBV) surface antigens on APCs targeted by vaccination and/or virus-harboring hepatocytes influences de novo priming of CD8(+) T cells. We showed that surface antigen-expressing transfectants exclusively display a K(b) /S190 epitope, whereas cells pulsed with recombinant surface particles (rSPs) exclusively present a K(b) /S208 epitope to CD8(+) T cells. The differential presentation of these epitopes largely reflects the selective, but not exclusive, priming of K(b) /S190- and K(b) /S208-specific T cells in C57BL/6 mice by endogenous/DNA- or exogenous/protein-based vaccines, respectively. Silencing the K(b) /S190 epitope (K(b) /S190V194F ) in antigen-expressing vectors rescued the presentation of the K(b) /S208 epitope in stable transfectants and significantly enhanced priming of K(b) /S208-specific T cells in C57BL/6 mice. A K(b) /S190-mediated immunodominance operating in surface antigen-expressing cells, but not in rSP-pulsed cells, led to an efficient suppression in the presentation of the K(b) /S208 epitope and a consequent decrease in the priming of K(b) /S208-specific T cells. This K(b) /S190-mediated immunodominance also operated in 1.4HBV-S(mut) transgenic (tg) hepatocytes selectively expressing endogenous surface antigens and allowed priming of K(b) /S208- but not K(b) /S190-specific T cells in 1.4HBV-S(mut) tg mice. However, IFN-γ(+) K(b) /S208-specific T cells could not inhibit HBV replication in the liver of 1.4HBV-S(mut) tg mice. These results have practical implications for the design of T-cell-stimulating therapeutic vaccines. PMID:24723392

  4. Adoptive transfer of Mammaglobin-A epitope specific CD8 T cells combined with a single low dose of total body irradiation eradicates breast tumors.

    Science.gov (United States)

    Lerret, Nadine M; Rogozinska, Magdalena; Jaramillo, Andrés; Marzo, Amanda L

    2012-01-01

    Adoptive T cell therapy has proven to be beneficial in a number of tumor systems by targeting the relevant tumor antigen. The tumor antigen targeted in our model is Mammaglobin-A, expressed by approximately 80% of human breast tumors. Here we evaluated the use of adoptively transferred Mammaglobin-A specific CD8 T cells in combination with low dose irradiation to induce breast tumor rejection and prevent relapse. We show Mammaglobin-A specific CD8 T cells generated by DNA vaccination with all epitopes (Mammaglobin-A2.1, A2.2, A2.4 and A2.6) and full-length DNA in vivo resulted in heterogeneous T cell populations consisting of both effector and central memory CD8 T cell subsets. Adoptive transfer of spleen cells from all Mammaglobin-A2 immunized mice into tumor-bearing SCID/beige mice induced tumor regression but this anti-tumor response was not sustained long-term. Additionally, we demonstrate that only the adoptive transfer of Mammaglobin-A2 specific CD8 T cells in combination with a single low dose of irradiation prevents tumors from recurring. More importantly we show that this single dose of irradiation results in the down regulation of the macrophage scavenger receptor 1 on dendritic cells within the tumor and reduces lipid uptake by tumor resident dendritic cells potentially enabling the dendritic cells to present tumor antigen more efficiently and aid in tumor clearance. These data reveal the potential for adoptive transfer combined with a single low dose of total body irradiation as a suitable therapy for the treatment of established breast tumors and the prevention of tumor recurrence.

  5. CD8(+ T cell cross-reactivity profiles and HIV-1 immune escape towards an HLA-B35-restricted immunodominant Nef epitope.

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    Chihiro Motozono

    Full Text Available Antigen cross-reactivity is an inbuilt feature of the T cell compartment. However, little is known about the flexibility of T cell recognition in the context of genetically variable pathogens such as HIV-1. In this study, we used a combinatorial library containing 24 billion octamer peptides to characterize the cross-reactivity profiles of CD8(+ T cells specific for the immunodominant HIV-1 subtype B Nef epitope VY8 (VPLRPMTY presented by HLA-B(*35∶01. In conjunction, we examined naturally occurring antigenic variations within the VY8 epitope. Sequence analysis of plasma viral RNA isolated from 336 HIV-1-infected individuals revealed variability at position (P 3 and P8 of VY8; Phe at P8, but not Val at P3, was identified as an HLA-B(*35∶01-associated polymorphism. VY8-specific T cells generated from several different HIV-1-infected patients showed unique and clonotype-dependent cross-reactivity footprints. Nonetheless, all T cells recognized both the index Leu and mutant Val at P3 equally well. In contrast, competitive titration assays revealed that the Tyr to Phe substitution at P8 reduced T cell recognition by 50-130 fold despite intact peptide binding to HLA-B(*35∶01. These findings explain the preferential selection of Phe at the C-terminus of VY8 in HLA-B(*35∶01(+ individuals and demonstrate that HIV-1 can exploit the limitations of T cell recognition in vivo.

  6. A cytomegalovirus-based vaccine expressing a single tumor-specific CD8+ T-cell epitope delays tumor growth in a murine model of prostate cancer.

    Science.gov (United States)

    Klyushnenkova, Elena N; Kouiavskaia, Diana V; Parkins, Christopher J; Caposio, Patrizia; Botto, Sara; Alexander, Richard B; Jarvis, Michael A

    2012-06-01

    Cytomegalovirus (CMV) is a highly immunogenic virus that results in a persistent, life-long infection in the host typically with no ill effects. Certain unique features of CMV, including its capacity to actively replicate in the presence of strong host CMV-specific immunity, may give CMV an advantage compared with other virus-based vaccine delivery platforms. In the present study, we tested the utility of mouse CMV (mCMV)-based vaccines expressing human prostate-specific antigen (PSA) for prostate cancer immunotherapy in double-transgenic mice expressing PSA and HLA-DRB1*1501 (DR2bxPSA F1 mice). We assessed the capacity of 2 mCMV-based vectors to induce PSA-specific CD8 T-cell responses and affect the growth of PSA-expressing Transgenic Adenocarcinoma of the Mouse Prostate tumors (TRAMP-PSA). In the absence of tumor challenge, immunization with mCMV vectors expressing either a H2-D(b)-restricted epitope PSA(65-73) (mCMV/PSA(65-73)) or the full-length gene for PSA (mCMV/PSA(FL)) induced comparable levels of CD8 T-cell responses that increased (inflated) with time. Upon challenge with TRAMP-PSA tumor cells, animals immunized with mCMV/PSA(65-73) had delay of tumor growth and increased PSA-specific CD8 T-cell responses, whereas animals immunized with mCMV/PSA(FL) showed progressive tumor growth and no increase in number of splenic PSA(65-73)-specific T cells. The data show that a prototype CMV-based prostate cancer vaccine can induce an effective antitumor immune response in a "humanized" double-transgenic mouse model. The observation that mCMV/PSA(FL) is not effective against TRAMP-PSA is consistent with our previous findings that HLA-DRB1*1501-restricted immune responses to PSA are associated with suppression of effective CD8 T-cell responses to TRAMP-PSA tumors.

  7. In silico analysis of six known Leishmania major antigens and in vitro evaluation of specific epitopes eliciting HLA-A2 restricted CD8 T cell response.

    Directory of Open Access Journals (Sweden)

    Negar Seyed

    2011-09-01

    Full Text Available BACKGROUND: As a potent CD8(+ T cell activator, peptide vaccine has found its way in vaccine development against intracellular infections and cancer, but not against leishmaniasis. The first step toward a peptide vaccine is epitope mapping of different proteins according to the most frequent HLA types in a population. METHODS AND FINDINGS: Six Leishmania (L. major-related candidate antigens (CPB,CPC,LmsTI-1,TSA,LeIF and LPG-3 were screened for potential CD8(+ T cell activating 9-mer epitopes presented by HLA-A*0201 (the most frequent HLA-A allele. Online software including SYFPEITHI, BIMAS, EpiJen, Rankpep, nHLApred, NetCTL and Multipred were used. Peptides were selected only if predicted by almost all programs, according to their predictive scores. Pan-A2 presentation of selected peptides was confirmed by NetMHCPan1.1. Selected peptides were pooled in four peptide groups and the immunogenicity was evaluated by in vitro stimulation and intracellular cytokine assay of PBMCs from HLA-A2(+ individuals recovered from L. major. HLA-A2(- individuals recovered from L. major and HLA-A2(+ healthy donors were included as control groups. Individual response of HLA-A2(+ recovered volunteers as percent of CD8(+/IFN-γ(+ T cells after in vitro stimulation against peptide pools II and IV was notably higher than that of HLA-A2(- recovered individuals. Based on cutoff scores calculated from the response of HLA-A2(- recovered individuals, 31.6% and 13.3% of HLA-A2(+ recovered persons responded above cutoff in pools II and IV, respectively. ELISpot and ELISA results confirmed flow cytometry analysis. The response of HLA-A2(- recovered individuals against peptide pools I and III was detected similar and even higher than HLA-A2(+ recovered individuals. CONCLUSION: Using in silico prediction we demonstrated specific response to LmsTI-1 (pool II and LPG-3- (pool IV related peptides specifically presented in HLA-A*0201 context. This is among the very few reports

  8. HLA-A2 and B35 restricted hantaan virus nucleoprotein CD8+ T-cell epitope-specific immune response correlates with milder disease in hemorrhagic fever with renal syndrome.

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    Ying Ma

    Full Text Available BACKGROUND: Hantaan virus (HTNV infection in humans is a serious public health concern in Asia. A potent T cell activation peptide vaccine from HTNV structure protein represents a promising immunotherapy for disease control. However, the T cell epitopes of the HTNV restricted by the HLA alleles and the role of epitope-specific T cell response after HTNV infection remain largely unexplored. METHODOLOGY/PRINCIPAL FINDINGS: Five well-conserved novel CD8(+ T-cell epitopes of the HTNV nucleoprotein restricted by the most popular HLA alleles in Chinese Han population were defined with interferon-γ enzyme-linked immunospot assay in 37 patients infected with HTNV during hospitalization. Two epitopes aa129-aa137 and aa131-aa139 restricted by HLA-A2 and B35, respectively, were selected to evaluate the epitope-specific CD8(+ T-cell response. HLA-peptide pentamer complex staining showed that the frequency of single epitope-specific CD8(+ T cell could be detected in patients (95% confidence interval for aa129-aa137: 0.080%-0.208%; for aa131-aa139: 0.030%-0.094%. The frequency of epitope-specific pentamer(+ CD8(+ T-cell response was much higher in mild/moderate patients than in severe/critical ones at the acute stage of the disease. Moreover, the frequency of epitope-specific CD8(+ T cells at acute stage was inversely associated with the peak level of serum creatinine and was positively associated with the nadir platelet counts during the hospitalization. The intracellular cytokine staining and the proliferation assay showed that the effective epitope-specific CD8(+ T cells were characterized with the production of interferon-γ, expression of CD69 and the strong capacity of proliferation. CONCLUSION/SIGNIFICANCE: The novel HLA class I restricted HTNV nucleoprotein epitopes-specific CD8(+ T-cell responses would be closely related with the progression and the severity of the disease, which could provide the first step toward effective peptide vaccine

  9. A novel HLA-B18 restricted CD8+ T cell epitope is efficiently cross-presented by dendritic cells from soluble tumor antigen.

    Directory of Open Access Journals (Sweden)

    Rona Y Zhao

    Full Text Available NY-ESO-1 has been a major target of many immunotherapy trials because it is expressed by various cancers and is highly immunogenic. In this study, we have identified a novel HLA-B*1801-restricted CD8(+ T cell epitope, NY-ESO-1(88-96 (LEFYLAMPF and compared its direct- and cross-presentation to that of the reported NY-ESO-1(157-165 epitope restricted to HLA-A*0201. Although both epitopes were readily cross-presented by DCs exposed to various forms of full-length NY-ESO-1 antigen, remarkably NY-ESO-1(88-96 is much more efficiently cross-presented from the soluble form, than NY-ESO-1(157-165. On the other hand, NY-ESO-1(157-165 is efficiently presented by NY-ESO-1-expressing tumor cells and its presentation was not enhanced by IFN-γ treatment, which induced immunoproteasome as demonstrated by Western blots and functionally a decreased presentation of Melan A(26-35; whereas NY-ESO-1(88-96 was very inefficiently presented by the same tumor cell lines, except for one that expressed high level of immunoproteasome. It was only presented when the tumor cells were first IFN-γ treated, followed by infection with recombinant vaccinia virus encoding NY-ESO-1, which dramatically increased NY-ESO-1 expression. These data indicate that the presentation of NY-ESO-1(88-96 is immunoproteasome dependent. Furthermore, a survey was conducted on multiple samples collected from HLA-B18(+ melanoma patients. Surprisingly, all the detectable responses to NY-ESO-1(88-96 from patients, including those who received NY-ESO-1 ISCOMATRIX™ vaccine were induced spontaneously. Taken together, these results imply that some epitopes can be inefficiently presented by tumor cells although the corresponding CD8(+ T cell responses are efficiently primed in vivo by DCs cross-presenting these epitopes. The potential implications for cancer vaccine strategies are further discussed.

  10. CD8(+) T cells specific to a single Yersinia pseudotuberculosis epitope restrict bacterial replication in the liver but fail to provide sterilizing immunity.

    Science.gov (United States)

    Shen, Haiqian; Gonzalez-Juarbe, Norberto; Blanchette, Krystle; Crimmins, Gregory; Bergman, Molly A; Isberg, Ralph R; Orihuela, Carlos J; Dube, Peter H

    2016-09-01

    CD8(+) T cells use contact-dependent cytolysis of target cells to protect the host against intracellular pathogens. We have previously shown that CD8(+) T cells and perforin are required to protect against the extracellular pathogen Yersinia pseudotuberculosis. Here we establish an experimental system where CD8(+) T cells specific to a single model antigen are the only memory response present at time of challenge. Using mice immunized with a vaccine strain of Listeria monocytogenes that expresses secreted ovalbumin (Lm-OVA), we show that OVA-specific CD8(+) T cells are generated and provide limited protection against challenge with virulent OVA(+)Y. pseudotuberculosis. Perforin expression by OVA-specific CD8(+) T cells was required, as Lm-OVA-immunized perforin-deficient mice showed higher bacterial burden as compared to Lm-OVA-immunized perforin-sufficient mice. Surprisingly, antigen-specific T cell protection waned over time, as Lm-OVA-immune mice eventually succumbed to Yersinia infection. Kinetic analysis of infection in mice with and without OVA-specific CD8(+) T cells revealed that bacterial numbers increased sharply in OVA-naïve mice until death, while OVA-immune mice held bacterial burden to a lower level throughout the duration of illness until death. Clonal analysis of bacterial populations in OVA-naïve and OVA-immune mice at distinct time points revealed equivalent and severe bottle-neck effects for bacteria in both sets of mice immediately after intravenous challenge, demonstrating a dominant role for other aspects of the immune system regardless of CD8(+) T cell status. These studies indicate that CD8(+) T cells against a single antigen can restrict Y. pseudotuberculosis colonization in a perforin-dependent manner, but ultimately are insufficient in their ability to provide sterilizing immunity and protect against death. PMID:27268148

  11. CD8(+) T cells specific to a single Yersinia pseudotuberculosis epitope restrict bacterial replication in the liver but fail to provide sterilizing immunity.

    Science.gov (United States)

    Shen, Haiqian; Gonzalez-Juarbe, Norberto; Blanchette, Krystle; Crimmins, Gregory; Bergman, Molly A; Isberg, Ralph R; Orihuela, Carlos J; Dube, Peter H

    2016-09-01

    CD8(+) T cells use contact-dependent cytolysis of target cells to protect the host against intracellular pathogens. We have previously shown that CD8(+) T cells and perforin are required to protect against the extracellular pathogen Yersinia pseudotuberculosis. Here we establish an experimental system where CD8(+) T cells specific to a single model antigen are the only memory response present at time of challenge. Using mice immunized with a vaccine strain of Listeria monocytogenes that expresses secreted ovalbumin (Lm-OVA), we show that OVA-specific CD8(+) T cells are generated and provide limited protection against challenge with virulent OVA(+)Y. pseudotuberculosis. Perforin expression by OVA-specific CD8(+) T cells was required, as Lm-OVA-immunized perforin-deficient mice showed higher bacterial burden as compared to Lm-OVA-immunized perforin-sufficient mice. Surprisingly, antigen-specific T cell protection waned over time, as Lm-OVA-immune mice eventually succumbed to Yersinia infection. Kinetic analysis of infection in mice with and without OVA-specific CD8(+) T cells revealed that bacterial numbers increased sharply in OVA-naïve mice until death, while OVA-immune mice held bacterial burden to a lower level throughout the duration of illness until death. Clonal analysis of bacterial populations in OVA-naïve and OVA-immune mice at distinct time points revealed equivalent and severe bottle-neck effects for bacteria in both sets of mice immediately after intravenous challenge, demonstrating a dominant role for other aspects of the immune system regardless of CD8(+) T cell status. These studies indicate that CD8(+) T cells against a single antigen can restrict Y. pseudotuberculosis colonization in a perforin-dependent manner, but ultimately are insufficient in their ability to provide sterilizing immunity and protect against death.

  12. Interdisciplinary Analysis of HIV-Specific CD8(+) T Cell Responses against Variant Epitopes Reveals Restricted TCR Promiscuity

    DEFF Research Database (Denmark)

    Hoof, Ilka; Perez, C.L.; Buggert, M.;

    2010-01-01

    investigated in a genetically diverse cohort of HIV-1 infected patients. Using a novel bioinformatic binding prediction method, we aimed to explain the pattern of epitope-specific CTL responses based on the patients' HLA genotype and autologous virus sequence quantitatively. Sequences covering predicted and...

  13. Generation of robust CD8+ T-cell responses against subdominant epitopes in conserved regions of HIV-1 by repertoire mining with mimotopes.

    Science.gov (United States)

    Schaubert, Keri L; Price, David A; Salkowitz, Janelle R; Sewell, Andrew K; Sidney, John; Asher, Tedi E; Blondelle, Sylvie E; Adams, Sharon; Marincola, Francesco M; Joseph, Aviva; Sette, Alessandro; Douek, Daniel C; Ayyavoo, Velpandi; Storkus, Walter; Leung, Ming-Ying; Ng, Hwee L; Yang, Otto O; Goldstein, Harris; Wilson, Darcy B; Kan-Mitchell, June

    2010-07-01

    HLA-A 0201-restricted virus-specific CD8(+) CTL do not appear to control HIV effectively in vivo. To enhance the immunogenicity of a highly conserved subdominant epitope, TV9 (TLNAWVKVV, p24 Gag(19-27)), mimotopes were designed by screening a large combinatorial nonapeptide library with TV9-specific CTL primed in vitro from healthy donors. A mimic peptide with a low binding affinity to HLA-A 0201, TV9p6 (KINAWIKVV), was studied further. Parallel cultures of in vitro-primed CTL showed that TV9p6 consistently activated cross-reactive and equally functional CTL as measured by cytotoxicity, cytokine production and suppression of HIV replication in vitro. Comparison of TCRB gene usage between CTL primed from the same donors with TV9 or TV9p6 revealed a degree of clonal overlap in some cases and an example of a conserved TCRB sequence encoded distinctly at the nucleotide level between individuals (a "public" TCR); however, in the main, distinct clonotypes were recruited by each peptide antigen. These findings indicate that mimotopes can mobilize functional cross-reactive clonotypes that are less readily recruited from the naïve T-cell pool by the corresponding WT epitope. Mimotope-induced repertoire diversification could potentially override subdominance under certain circumstances and enhance vaccine-induced responses to conserved but poorly immunogenic determinants within the HIV proteome. PMID:20432235

  14. CD8 and CD4 epitope predictions in RV144: no strong evidence of a T-cell driven sieve effect in HIV-1 breakthrough sequences from trial participants.

    Directory of Open Access Journals (Sweden)

    Kalpana Dommaraju

    Full Text Available The modest protection afforded by the RV144 vaccine offers an opportunity to evaluate its mechanisms of protection. Differences between HIV-1 breakthrough viruses from vaccine and placebo recipients can be attributed to the RV144 vaccine as this was a randomized and double-blinded trial. CD8 and CD4 T cell epitope repertoires were predicted in HIV-1 proteomes from 110 RV144 participants. Predicted Gag epitope repertoires were smaller in vaccine than in placebo recipients (p = 0.019. After comparing participant-derived epitopes to corresponding epitopes in the RV144 vaccine, the proportion of epitopes that could be matched differed depending on the protein conservation (only 36% of epitopes in Env vs 84-91% in Gag/Pol/Nef for CD8 predicted epitopes or on vaccine insert subtype (55% against CRF01_AE vs 7% against subtype B. To compare predicted epitopes to the vaccine, we analyzed predicted binding affinity and evolutionary distance measurements. Comparisons between the vaccine and placebo arm did not reveal robust evidence for a T cell driven sieve effect, although some differences were noted in Env-V2 (0.022≤p-value≤0.231. The paucity of CD8 T cell responses identified following RV144 vaccination, with no evidence for V2 specificity, considered together both with the association of decreased infection risk in RV 144 participants with V-specific antibody responses and a V2 sieve effect, lead us to hypothesize that this sieve effect was not T cell specific. Overall, our results did not reveal a strong differential impact of vaccine-induced T cell responses among breakthrough infections in RV144 participants.

  15. Identification of an HLA-A* 0201-restricted CD8+ T-cell epitope SSp-1 of SARS-CoV spike protein

    Institute of Scientific and Technical Information of China (English)

    Wang B; Yu Y; Wang X; Yang R; Cao X; Chen H; Jiang X; Zhang M; Wan T; Li N; Zhou X; Wu Y; Yang F

    2004-01-01

    A novel coronavirus, severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV), has been identified as the causal agent of SARS. Spike (S) protein is a major structural glycoprotein of the SARS virus and a potential target for SARS-specific cell-mediated immune responses. A panel of S protein-derived peptides was tested for their binding affinity to HLA-A * 0201 molecules. Peptides with high affinity for HLA-A * 0201 were then assessed for their capacity to elicit specific immune responses mediated by cytotoxic T lymphocytes (CTLs) both in vivo, in HLA-A2. 1/Kb transgenic mice, and in vitro, from peripheral blood lymphocytes (PBLs) harvested from healthy HLA-A2.1 + donors. SARS-CoV protein-derived peptide-1 (SSp-1 RLNEVAKNL), induced peptide-specific CTLs both in vivo (transgenic mice) and in vitro (human PBLs), which specifically released interferon-gamma (IFN-gamma) upon stimulation with SSp-1-pulsed autologous dendritic cells (DCs) or T2 cells. SSp-1-specific CTLs also lysed major histocompatibility complex (MHC)-matched tumor cell lines engineered to express S proteins. HLA-A * 0201-SSp-1 tetramer staining revealed the presence of significant populations of SSp-1-specific CTLs in SSp-1-induced CD8+ T cells. We propose that the newly identified epitope SSp-1 will help in the characterization of virus control mechanisms and immunopathology in SARS-CoV infection, and may be relevant to the development of immunotherapeutic approaches for SARS.

  16. Identification of CD4+ and CD8+ T cell epitopes of woodchuck hepatitis virus core and surface antigens in BALB/c mice

    OpenAIRE

    Ochoa, L. (Laura); Otano, I. (Itziar); Vales, A.; Olagüe, C. (Cristina); Sarobe, P. (Pablo); Lasarte, J. J.; Menne, S; Prieto, J.; Gonzalez-Aseguinolaza, G

    2010-01-01

    A therapeutic vaccine against chronic hepatitis B virus (HBV) infection requires the development of a strong and multispecific Th1 cell immune response. Woodchucks chronically infected with the woodchuck hepatitis virus (WHV) closely resemble HBV infection and represent the best animal model for this hepadnavirus-induced disease. Using the BIMAS "HLA Peptide Binding Predictions" program, we have identified and further characterized novel H-2(d)-restricted CD8+ epitopes within the WHV core (pe...

  17. Codon optimization of the human papillomavirus E7 oncogene induces a CD8+ T cell response to a cryptic epitope not harbored by wild-type E7.

    Directory of Open Access Journals (Sweden)

    Felix K M Lorenz

    Full Text Available Codon optimization of nucleotide sequences is a widely used method to achieve high levels of transgene expression for basic and clinical research. Until now, immunological side effects have not been described. To trigger T cell responses against human papillomavirus, we incubated T cells with dendritic cells that were pulsed with RNA encoding the codon-optimized E7 oncogene. All T cell receptors isolated from responding T cell clones recognized target cells expressing the codon-optimized E7 gene but not the wild type E7 sequence. Epitope mapping revealed recognition of a cryptic epitope from the +3 alternative reading frame of codon-optimized E7, which is not encoded by the wild type E7 sequence. The introduction of a stop codon into the +3 alternative reading frame protected the transgene product from recognition by T cell receptor gene-modified T cells. This is the first experimental study demonstrating that codon optimization can render a transgene artificially immunogenic through generation of a dominant cryptic epitope. This finding may be of great importance for the clinical field of gene therapy to avoid rejection of gene-corrected cells and for the design of DNA- and RNA-based vaccines, where codon optimization may artificially add a strong immunogenic component to the vaccine.

  18. Identification of a naturally processed cytotoxic CD8 T-cell epitope of coxsackievirus B4, presented by HLA-A2.1 and located in the PEVKEK region of the P2C nonstructural protein.

    Science.gov (United States)

    Varela-Calvino, Ruben; Skowera, Ania; Arif, Sefina; Peakman, Mark

    2004-12-01

    The adaptive immune system generates CD8 cytotoxic T lymphocytes (CTLs) as a major component of the protective response against viruses. Knowledge regarding the nature of the peptide sequences presented by HLA class I molecules and recognized by CTLs is thus important for understanding host-pathogen interactions. In this study, we focused on identification of a CTL epitope generated from coxsackievirus B4 (CVB4), a member of the enterovirus group responsible for several inflammatory diseases in humans and often implicated in the triggering and/or acceleration of the autoimmune disease type 1 diabetes. We identified a 9-mer peptide epitope that can be generated from the P2C nonstructural protein of CVB4 (P2C(1137-1145)) and from whole virus by antigen-presenting cells and presented by HLA-A2.1. This epitope is recognized by effector memory (gamma interferon [IFN-gamma]-producing) CD8 T cells in the peripheral blood at a frequency of responders that suggests that it is a major focus of the anti-CVB4 response. Short-term CD8 T-cell lines generated against P2C(1137-1145) are cytotoxic against peptide-loaded target cells. Of particular interest, the epitope lies within a region of viral homology with the diabetes-related autoantigen, glutamic acid decarboxylase-65 (GAD(65)). However, P2C(1137-1145)-specific cytotoxic T lymphocyte (CTL) lines were not activated to produce IFN-gamma by the GAD(65) peptide homologue and did not show cytotoxic activity in the presence of appropriately labeled targets. These results describe the first CD8 T-cell epitope of CVB4 that will prove useful in the study of CVB4-associated disease. PMID:15564450

  19. Montanide, Poly I:C and nanoparticle based vaccines promote differential suppressor and effector cell expansion: a study of induction of CD8 T cells to a minimal Plasmodium berghei epitope

    Directory of Open Access Journals (Sweden)

    Kirsty Lee Wilson

    2015-02-01

    Full Text Available The development of practical and flexible vaccines to target liver stage malaria parasites would benefit from an ability to induce high levels of CD8 T cells to minimal peptide epitopes. Herein we compare different adjuvant and carrier systems in a murine model for induction of interferon gamma (IFN-γ producing CD8 T cells to the minimal immuno-dominant peptide epitope from the circumsporozoite protein (CSP of Plasmodium berghei, pb9 (SYIPSAEKI, referred to as KI. Two pro-inflammatory adjuvants, Montanide and Poly I:C, and a non-classical, non-inflammatory nanoparticle based carrier (polystyrene nanoparticles, PSNPs, were compared side-by-side for their ability to induce potentially protective CD8 T cell responses after two immunisations. KI in Montanide (Montanide + KI or covalently conjugated to PSNPs (PSNPs-KI induced such high responses, whereas adjuvanting with Poly I:C or PSNPs without conjugation was ineffective. This result was consistent with an observed induction of an immunosuppressed environment by Poly I:C in the draining lymph node (dLN 48 hours post injection, which was reflected by increased frequencies of myeloid derived suppressor cells (MDSC and a proportion of inflammation reactive regulatory T cells (Treg expressing the tumour necrosis factor receptor 2 (TNFR2, as well as decreased dendritic cell (DC maturation. The other inflammatory adjuvant, Montanide, also promoted proportional increases in the TNFR2+ Treg subpopulation, but not MDSCs, in the dLN. By contrast, injection with non-inflammatory PSNPs did not cause these changes. Induction of high CD8 T cell responses, using minimal peptide epitopes, can be achieved by non-inflammatory carrier nanoparticles, which in contrast to some conventional inflammatory adjuvants, do not expand either MDSCs or inflammation reactive Tregs at the site of priming.

  20. Inferring Protective CD8+ T-Cell Epitopes for NS5 Protein of Four Serotypes of Dengue Virus Chinese Isolates Based on HLA-A, -B and -C Allelic Distribution: Implications for Epitope-Based Universal Vaccine Design.

    Directory of Open Access Journals (Sweden)

    Jiandong Shi

    Full Text Available Dengue is one of the most globally serious vector-borne infectious diseases in tropical and subtropical areas for which there are currently no effective vaccines. The most highly conserved flavivirus protein, NS5, is an indispensable target of CD8+ T-cells, making it an ideal vaccine design target. Using the Immune Epitope Database (IEDB, CD8+ T-cell epitopes of the dengue virus (DENV NS5 protein were predicted by genotypic frequency of the HLA-A,-B, and-C alleles in Chinese population. Antigenicity scores of all predicted epitopes were analyzed using VaxiJen v2.0. The IEDB analysis revealed that 116 antigenic epitopes for HLA-A (21,-B (53, and-C (42 had high affinity for HLA molecules. Of them, 14 had 90.97-99.35% conversancy among the four serotypes. Moreover, five candidate epitopes, including 200NS5210 (94.84%, A*11:01, 515NS5525 (98.71%, A*24:02, 225NS5232 (99.35%, A*33:03, 516NS5523 (98.71%, A*33:03, and 284NS5291 (98.06%, A*33:03, were presented by HLA-A. Four candidate epitopes, including 234NS5241 (96.77%, B*13:01, 92NS599 (98.06%, B*15:01, B*15:02, and B*46:01, 262NS5269 (92.90%, B*38:02, and 538NS5547 (90.97%, B*51:01, were presented by HLA-B. Another 9 candidate epitopes, including 514NS5522 (98.71%, C*01:02, 514NS5524 (98.71%, C*01:02 and C*14:02, 92NS599 (98.06%, C*03:02 and C*15:02, 362NS5369 (44.84%, C*03:04 and C*08:01, 225NS5232 (99.35%, C*04:01, 234NS5241(96.77%, C*04:01, 361NS5369 (94.84%, C*04:01, 515NS5522 (98.71%, C*14:02, 515NS5524 (98.71%, C*14:02, were presented by HLA-C. Further data showed that the four-epitope combination of 92NS599 (B*15:01, B*15:02, B*46:01, C*03:02 and C*15:02, 200NS5210 (A*11:01, 362NS5369 (C*03:04, C*08:01, and 514NS5524 (C*01:02, C*14:02 could vaccinate >90% of individuals in China. Further in vivo study of our inferred novel epitopes will be needed for a T-cell epitope-based universal vaccine development that may prevent all four China-endemic DENV serotypes.

  1. CD8+ T cells in inflammatory demyelinating disease

    DEFF Research Database (Denmark)

    Weiss, Hanne A; Millward, Jason M; Owens, Trevor

    2007-01-01

    We review the contribution made by CD8+ T cells to inflammation in the central nervous system (CNS) in Multiple Sclerosis (MS), and discuss their role in the animal model Experimental Autoimmune Encephalomyelitis (EAE). We show that the inflammatory cytokines interferon-gamma and interleukin-17...... are differentially regulated in CNS-infiltrating CD4+ and CD8+ T cells in EAE, and that CD8+ T cells regulate disease. In MS, CD8+ T cells appear to play a role in promotion of disease, so cytokine regulation is likely different in CD8+ T cells in MS and EAE...

  2. CD4+/CD8+ double-positive T cells

    DEFF Research Database (Denmark)

    Overgaard, Nana H; Jung, Ji-Won; Steptoe, Raymond J;

    2015-01-01

    CD4(+)/CD8(+) DP thymocytes are a well-described T cell developmental stage within the thymus. However, once differentiated, the CD4(+) lineage or the CD8(+) lineage is generally considered to be fixed. Nevertheless, mature CD4(+)/CD8(+) DP T cells have been described in the blood and peripheral...... cells, CD4(+)/CD8(+) T cell populations, outside of the thymus, have recently been described to express concurrently ThPOK and Runx3. Considerable heterogeneity exists within the CD4(+)/CD8(+) DP T cell pool, and the function of CD4(+)/CD8(+) T cell populations remains controversial, with conflicting...... reports describing cytotoxic or suppressive roles for these cells. In this review, we describe how transcriptional regulation, lineage of origin, heterogeneity of CD4 and CD8 expression, age, species, and specific disease settings influence the functionality of this rarely studied T cell population....

  3. CD8+ T cells in Leishmania infections: friends or foes?

    Directory of Open Access Journals (Sweden)

    Simona eStager

    2012-01-01

    Full Text Available Host protection against several intracellular pathogens requires the induction of CD8+ T cell responses. CD8+ T cells are potent effector cells that can produce high amounts of pro-inflammatory cytokines and kill infected target cells efficiently. However, a protective role for CD8+ T cells during Leishmania infections is still controversial and largely depends on the infection model. In this review, we discuss the role of CD8+ T cells during various types Leishmania infections, following vaccination, and as potential immunotherapeutic targets.

  4. Consensus nomenclature for CD8+ T cell phenotypes in cancer

    Science.gov (United States)

    Apetoh, Lionel; Smyth, Mark J.; Drake, Charles G.; Abastado, Jean-Pierre; Apte, Ron N.; Ayyoub, Maha; Blay, Jean-Yves; Bonneville, Marc; Butterfield, Lisa H.; Caignard, Anne; Castelli, Chiara; Cavallo, Federica; Celis, Esteban; Chen, Lieping; Colombo, Mario P.; Comin-Anduix, Begoña; Coukos, Georges; Dhodapkar, Madhav V.; Dranoff, Glenn; Frazer, Ian H.; Fridman, Wolf-Hervé; Gabrilovich, Dmitry I.; Gilboa, Eli; Gnjatic, Sacha; Jäger, Dirk; Kalinski, Pawel; Kaufman, Howard L.; Kiessling, Rolf; Kirkwood, John; Knuth, Alexander; Liblau, Roland; Lotze, Michael T.; Lugli, Enrico; Marincola, Francesco; Melero, Ignacio; Melief, Cornelis J.; Mempel, Thorsten R.; Mittendorf, Elizabeth A.; Odun, Kunle; Overwijk, Willem W.; Palucka, Anna Karolina; Parmiani, Giorgio; Ribas, Antoni; Romero, Pedro; Schreiber, Robert D.; Schuler, Gerold; Srivastava, Pramod K.; Tartour, Eric; Valmori, Danila; van der Burg, Sjoerd H.; van der Bruggen, Pierre; van den Eynde, Benoît J.; Wang, Ena; Zou, Weiping; Whiteside, Theresa L.; Speiser, Daniel E.; Pardoll, Drew M.; Restifo, Nicholas P.; Anderson, Ana C.

    2015-01-01

    Whereas preclinical investigations and clinical studies have established that CD8+ T cells can profoundly affect cancer progression, the underlying mechanisms are still elusive. Challenging the prevalent view that the beneficial effect of CD8+ T cells in cancer is solely attributable to their cytotoxic activity, several reports have indicated that the ability of CD8+ T cells to promote tumor regression is dependent on their cytokine secretion profile and their ability to self-renew. Evidence has also shown that the tumor microenvironment can disarm CD8+ T cell immunity, leading to the emergence of dysfunctional CD8+ T cells. The existence of different types of CD8+ T cells in cancer calls for a more precise definition of the CD8+ T cell immune phenotypes in cancer and the abandonment of the generic terms “pro-tumor” and “antitumor.” Based on recent studies investigating the functions of CD8+ T cells in cancer, we here propose some guidelines to precisely define the functional states of CD8+ T cells in cancer. PMID:26137416

  5. Features that shape CD8+ T-cell responses to viruses

    NARCIS (Netherlands)

    Correia de Almeida Fontaine Costa, A.I.

    2014-01-01

    CD8+ T cells, via their specific T-cell receptor (TCR), target infected cells when recognizing pathogen-derived peptides (epitopes) bound to class I major histocompatibility complex molecules (MHCI, or HLA-class I in humans). HLA-B is the most polymorphic of the classical HLA-I molecules. HLA-B-rest

  6. Induction of Specific CD8+ T Cells against Intracellular Bacteria by CD8+ T-Cell-Oriented Immunization Approaches

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    Toshi Nagata

    2010-01-01

    Full Text Available For protection against intracellular bacteria such as Mycobacterium tuberculosis and Listeria monocytogenes, the cellular arm of adaptive immunity is necessary. A variety of immunization methods have been evaluated and are reported to induce specific CD8+ T cells against intracellular bacterial infection. Modified BCG vaccines have been examined to enhance CD8+ T-cell responses. Naked DNA vaccination is a promising strategy to induce CD8+ T cells. In addition to this strategy, live attenuated intracellular bacteria such as Shigella, Salmonella, and Listeria have been utilized as carriers of DNA vaccines in animal models. Vaccination with dendritic cells pulsed with antigenic peptides or the cells introduced antigen genes by virus vectors such as retroviruses is also a powerful strategy. Furthermore, vaccination with recombinant lentivirus has been attempted to induce specific CD8+ T cells. Combinations of these strategies (prime-boost immunization have been studied for the efficient induction of intracellular bacteria-specific CD8+ T cells.

  7. The efficiency of human cytomegalovirus pp65(495-503) CD8+ T cell epitope generation is determined by the balanced activities of cytosolic and endoplasmic reticulum-resident peptidases.

    Science.gov (United States)

    Urban, Sabrina; Textoris-Taube, Kathrin; Reimann, Barbara; Janek, Katharina; Dannenberg, Tanja; Ebstein, Frédéric; Seifert, Christin; Zhao, Fang; Kessler, Jan H; Halenius, Anne; Henklein, Petra; Paschke, Julia; Cadel, Sandrine; Bernhard, Helga; Ossendorp, Ferry; Foulon, Thierry; Schadendorf, Dirk; Paschen, Annette; Seifert, Ulrike

    2012-07-15

    Control of human CMV (HCMV) infection depends on the cytotoxic activity of CD8(+) CTLs. The HCMV phosphoprotein (pp)65 is a major CTL target Ag and pp65(495-503) is an immunodominant CTL epitope in infected HLA-A*0201 individuals. As immunodominance is strongly determined by the surface abundance of the specific epitope, we asked for the components of the cellular Ag processing machinery determining the efficacy of pp65(495-503) generation, in particular, for the proteasome, cytosolic peptidases, and endoplasmic reticulum (ER)-resident peptidases. In vitro Ag processing experiments revealed that standard proteasomes and immunoproteasomes generate the minimal 9-mer peptide epitope as well as N-terminal elongated epitope precursors of different lengths. These peptides are largely degraded by the cytosolic peptidases leucine aminopeptidase and tripeptidyl peptidase II, as evidenced by increased pp65(495-503) epitope presentation after leucine aminopeptidase and tripeptidyl peptidase II knockdown. Additionally, with prolyl oligopeptidase and aminopeptidase B we identified two new Ag processing machinery components, which by destroying the pp65(495-503) epitope limit the availability of the specific peptide pool. In contrast to cytosolic peptidases, silencing of ER aminopeptidases 1 and 2 strongly impaired pp65(495-503)-specific T cell activation, indicating the importance of ER aminopeptidases in pp65(495-503) generation. Thus, cytosolic peptidases primarily interfere with the generation of the pp65(495-503) epitope, whereas ER-resident aminopeptidases enhance such generation. As a consequence, our experiments reveal that the combination of cytosolic and ER-resident peptidase activities strongly shape the pool of specific antigenic peptides and thus modulate MHC class I epitope presentation efficiency. PMID:22706083

  8. Adoptive immunotherapy via CD4+ versus CD8+ T cells

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    Vy Phan-Lai

    2016-04-01

    Full Text Available The goal of cancer immunotherapy is to induce specific and durable antitumor immunity. Adoptive T cell therapy (ACT has garnered wide interest, particularly in regard to strategies to improve T cell efficacy in trials. There are many types of T cells (and subsets which can be selected for use in ACT. CD4+ T cells are critical for the regulation, activation and aid of host defense mechanisms and, importantly, for enhancing the function of tumor-specific CD8+ T cells. To date, much research in cancer immunotherapy has focused on CD8+ T cells, in melanoma and other cancers. Both CD4+ T cells and CD8+ T cells have been evaluated as ACT in mice and humans, and both are effective at eliciting antitumor responses. IL-17 producing CD4+ T cells are a new subset of CD4+ T cells to be evaluated in ACT models. This review discusses the benefits of adoptive immunotherapy mediated by CD8+ and CD4+ cells. It also discusses the various type of T cells, source of T cells, and ex vivo cytokine growth factors for augmenting clinical efficacy of ACT. [Biomed Res Ther 2016; 3(4.000: 588-595

  9. The role of CD8+ T cells during allograft rejection

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    Bueno V.

    2002-01-01

    Full Text Available Organ transplantation can be considered as replacement therapy for patients with end-stage organ failure. The percent of one-year allograft survival has increased due, among other factors, to a better understanding of the rejection process and new immunosuppressive drugs. Immunosuppressive therapy used in transplantation prevents activation and proliferation of alloreactive T lymphocytes, although not fully preventing chronic rejection. Recognition by recipient T cells of alloantigens expressed by donor tissues initiates immune destruction of allogeneic transplants. However, there is controversy concerning the relative contribution of CD4+ and CD8+ T cells to allograft rejection. Some animal models indicate that there is an absolute requirement for CD4+ T cells in allogeneic rejection, whereas in others CD4-depleted mice reject certain types of allografts. Moreover, there is evidence that CD8+ T cells are more resistant to immunotherapy and tolerance induction protocols. An intense focal infiltration of mainly CD8+CTLA4+ T lymphocytes during kidney rejection has been described in patients. This suggests that CD8+ T cells could escape from immunosuppression and participate in the rejection process. Our group is primarily interested in the immune mechanisms involved in allograft rejection. Thus, we believe that a better understanding of the role of CD8+ T cells in allograft rejection could indicate new targets for immunotherapy in transplantation. Therefore, the objective of the present review was to focus on the role of the CD8+ T cell population in the rejection of allogeneic tissue.

  10. Host and viral factors contributing to CD8+ T cell failure in hepatitis C virus infection

    Institute of Scientific and Technical Information of China (English)

    Christoph Neumann-Haefelin; Hans Christian Spangenberg; Hubert E Blum; Robert Thimme

    2007-01-01

    Virus-specific CD8+ T cells are thought to be the major anti-viral effector cells in hepatitis C virus (HCV)infection. Indeed, viral clearance is associated with vigorous CD8+ T cell responses targeting multiple epitopes. In the chronic phase of infection, HCV-specific CD8+ T cell responses are usually weak, narrowly focused and display often functional defects regarding cytotoxicity, cytokine production, and proliferative capacity. In the last few years, different mechanisms which might contribute to the failure of HCV-specific CD8+ T cells in chronic infection have been identified,including insufficient CD4+ help, deficient CD8+ T cell differentiation, viral escape mutations, suppression by viral factors, inhibitory cytokines, inhibitory ligands, and regulatory T cells. In addition, host genetic factors such as the host's human leukocyte antigen (HLA) background may play an important role in the efficiency of the HCVspecific CD8+ T cell response and thus outcome of infection. The growing understanding of the mechanisms contributing to T cell failure and persistence of HCV infection will contribute to the development of successful immunotherapeutical and -prophylactical strategies.

  11. Mesenchymal stem cells differentially modulate effector CD8+ T cell subsets and exacerbate experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Glenn, Justin D; Smith, Matthew D; Calabresi, Peter A; Whartenby, Katharine A

    2014-10-01

    Mesenchymal stem cells (MSC) have emerged as a promising candidate for inflammatory suppression and disease amelioration, especially of neuro-inflammatory diseases such as multiple sclerosis (MS). Auto-reactive CD4+ and CD8+ T cells acquire pathogenic IFNγ-producing- (Type I) and IL-17A-producing- (Type 17) effector phenotypes in MS and its animal model experimental autoimmune encephalomyelitis (EAE). Although MSC have been extensively demonstrated to suppress pathogenic effector CD4+ T cells and CD4+ T cell-mediated EAE, surprisingly few studies have addressed their modulation of effector CD8+ T cells represented in MS or their impact on CD8+ T cell-mediated EAE. We find that MSC differentially modulate CD8+ T cell development depending on effector T cell subtype. MSC drive activated low-IFNγ producers toward an enhanced high-IFNγ Tc1-like phenotype but strongly inhibit the production of IL-17A and Tc17 polarization in vitro. These observations are underscored by differential MSC modulation of T cell activation, proliferation, and signature transcription factor up-regulation. In addition, effector CD8+ T cells co-cultured with MSC exhibited increased production of IL-2, a molecule known to enhance IFNγ, yet suppress IL-17A, production. Based on these in vitro effects on CD8+ T cells, we next evaluated their impact on the severity of EAE. To better evaluate CD8+ T cells, we immunized mice with MOG37-50 , which is a CD8-targeted epitope. Our results revealed a worsening of disease, consistent with their in vitro stimulation of Tc1 cells. These findings highlight the emerging duality of MSC in immune modulation and provide implications for their future use in immune-related diseases. PMID:24911892

  12. Combination of In Silico Methods in the Search for Potential CD4(+) and CD8(+) T Cell Epitopes in the Proteome of Leishmania braziliensis.

    Science.gov (United States)

    E Silva, Rafael de Freitas; Ferreira, Luiz Felipe Gomes Rebello; Hernandes, Marcelo Zaldini; de Brito, Maria Edileuza Felinto; de Oliveira, Beatriz Coutinho; da Silva, Ailton Alvaro; de-Melo-Neto, Osvaldo Pompílio; Rezende, Antônio Mauro; Pereira, Valéria Rêgo Alves

    2016-01-01

    The leishmaniases are neglected tropical diseases widespread throughout the globe, which are caused by protozoans from the genus Leishmania and are transmitted by infected phlebotomine flies. The development of a safe and effective vaccine against these diseases has been seen as the best alternative to control and reduce the number of cases. To support vaccine development, this work has applied an in silico approach to search for high potential peptide epitopes able to bind to different major histocompatibility complex Class I and Class II (MHC I and MHC II) molecules from different human populations. First, the predicted proteome of Leishmania braziliensis was compared and analyzed by modern linear programs to find epitopes with the capacity to trigger an immune response. This approach resulted in thousands of epitopes derived from 8,000 proteins conserved among different Leishmania species. Epitopes from proteins similar to those found in host species were excluded, and epitopes from proteins conserved between different Leishmania species and belonging to surface proteins were preferentially selected. The resulting epitopes were then clustered, to avoid redundancies, resulting in a total of 230 individual epitopes for MHC I and 2,319 for MHC II. These were used for molecular modeling and docking with MHC structures retrieved from the Protein Data Bank. Molecular docking then ranked epitopes based on their predicted binding affinity to both MHC I and II. Peptides corresponding to the top 10 ranked epitopes were synthesized and evaluated in vitro for their capacity to stimulate peripheral blood mononuclear cells (PBMC) from post-treated cutaneous leishmaniasis patients, with PBMC from healthy donors used as control. From the 10 peptides tested, 50% showed to be immunogenic and capable to stimulate the proliferation of lymphocytes from recovered individuals.

  13. Combination of In Silico Methods in the Search for Potential CD4(+) and CD8(+) T Cell Epitopes in the Proteome of Leishmania braziliensis.

    Science.gov (United States)

    E Silva, Rafael de Freitas; Ferreira, Luiz Felipe Gomes Rebello; Hernandes, Marcelo Zaldini; de Brito, Maria Edileuza Felinto; de Oliveira, Beatriz Coutinho; da Silva, Ailton Alvaro; de-Melo-Neto, Osvaldo Pompílio; Rezende, Antônio Mauro; Pereira, Valéria Rêgo Alves

    2016-01-01

    The leishmaniases are neglected tropical diseases widespread throughout the globe, which are caused by protozoans from the genus Leishmania and are transmitted by infected phlebotomine flies. The development of a safe and effective vaccine against these diseases has been seen as the best alternative to control and reduce the number of cases. To support vaccine development, this work has applied an in silico approach to search for high potential peptide epitopes able to bind to different major histocompatibility complex Class I and Class II (MHC I and MHC II) molecules from different human populations. First, the predicted proteome of Leishmania braziliensis was compared and analyzed by modern linear programs to find epitopes with the capacity to trigger an immune response. This approach resulted in thousands of epitopes derived from 8,000 proteins conserved among different Leishmania species. Epitopes from proteins similar to those found in host species were excluded, and epitopes from proteins conserved between different Leishmania species and belonging to surface proteins were preferentially selected. The resulting epitopes were then clustered, to avoid redundancies, resulting in a total of 230 individual epitopes for MHC I and 2,319 for MHC II. These were used for molecular modeling and docking with MHC structures retrieved from the Protein Data Bank. Molecular docking then ranked epitopes based on their predicted binding affinity to both MHC I and II. Peptides corresponding to the top 10 ranked epitopes were synthesized and evaluated in vitro for their capacity to stimulate peripheral blood mononuclear cells (PBMC) from post-treated cutaneous leishmaniasis patients, with PBMC from healthy donors used as control. From the 10 peptides tested, 50% showed to be immunogenic and capable to stimulate the proliferation of lymphocytes from recovered individuals. PMID:27621732

  14. Combination of In Silico Methods in the Search for Potential CD4+ and CD8+ T Cell Epitopes in the Proteome of Leishmania braziliensis

    Science.gov (United States)

    e Silva, Rafael de Freitas; Ferreira, Luiz Felipe Gomes Rebello; Hernandes, Marcelo Zaldini; de Brito, Maria Edileuza Felinto; de Oliveira, Beatriz Coutinho; da Silva, Ailton Alvaro; de-Melo-Neto, Osvaldo Pompílio; Rezende, Antônio Mauro; Pereira, Valéria Rêgo Alves

    2016-01-01

    The leishmaniases are neglected tropical diseases widespread throughout the globe, which are caused by protozoans from the genus Leishmania and are transmitted by infected phlebotomine flies. The development of a safe and effective vaccine against these diseases has been seen as the best alternative to control and reduce the number of cases. To support vaccine development, this work has applied an in silico approach to search for high potential peptide epitopes able to bind to different major histocompatibility complex Class I and Class II (MHC I and MHC II) molecules from different human populations. First, the predicted proteome of Leishmania braziliensis was compared and analyzed by modern linear programs to find epitopes with the capacity to trigger an immune response. This approach resulted in thousands of epitopes derived from 8,000 proteins conserved among different Leishmania species. Epitopes from proteins similar to those found in host species were excluded, and epitopes from proteins conserved between different Leishmania species and belonging to surface proteins were preferentially selected. The resulting epitopes were then clustered, to avoid redundancies, resulting in a total of 230 individual epitopes for MHC I and 2,319 for MHC II. These were used for molecular modeling and docking with MHC structures retrieved from the Protein Data Bank. Molecular docking then ranked epitopes based on their predicted binding affinity to both MHC I and II. Peptides corresponding to the top 10 ranked epitopes were synthesized and evaluated in vitro for their capacity to stimulate peripheral blood mononuclear cells (PBMC) from post-treated cutaneous leishmaniasis patients, with PBMC from healthy donors used as control. From the 10 peptides tested, 50% showed to be immunogenic and capable to stimulate the proliferation of lymphocytes from recovered individuals.

  15. Programming CD8+ T cells for effective immunotherapy

    OpenAIRE

    Hinrichs, Christian S.; Gattinoni, Luca; Restifo, Nicholas P

    2006-01-01

    The differentiation state of CD8+ T cells has emerged as a crucial determinant of their ability to respond to tumor and infection. Signals from T-cell receptors, co-stimulatory molecules and cytokine receptors direct the differentiation process. These signals ‘program’ sustained and heritable gene expression patterns that govern progressive differentiation and lineage commitment. The epigenetic mechanisms by which T cells are programmed are just beginning to be elucidated. Understanding the m...

  16. Induction of novel CD8+ T-cell responses during chronic untreated HIV-1 infection by immunization with subdominant cytotoxic T-lymphocyte epitopes

    DEFF Research Database (Denmark)

    Kloverpris, Henrik; Karlsson, Ingrid; Bonde, Jesper;

    2009-01-01

    OBJECTIVE:: To investigate the potential to induce additional cytotoxic T-lymphocyte (CTL) immunity during chronic HIV-1 infection. DESIGN:: We selected infrequently targeted or subdominant but conserved HLA-A*0201-binding epitopes in Gag, Pol, Env, Vpu and Vif. These relatively immune silent epi...... lead to stronger and more durable cellular responses to selected epitopes with the potential to control viral replication and prevent disease in HIV-1-infected individuals....

  17. Role of CD8+ regulatory T cells in organ transplantation

    Directory of Open Access Journals (Sweden)

    Jiyan Su

    2014-01-01

    Full Text Available CD8 + T cells are regulatory T cells (Tregs that suppress both alloimmunity and autoimmunity in many animal models. This class of regulatory cells includes the CD8 + CD28 - , CD8 + CD103 + , CD8 + FoxP3 + and CD8 + CD122 + subsets. The mechanisms of action of these regulatory cells are not fully understood; however, the secretion of immunosuppressive cytokines, such as interleukin (IL-4, IL-10 and transforming growth factor beta (TGF-β as well as the direct killing of target cells via Fas L/Fas and the perforin/granzyme B pathways have been demonstrated in various models. Further studies are necessary to fully understand the mechanisms underlying the suppressive effects of Tregs and to provide experimental support for potential clinical trials. We recently observed that CD8 + CD122 + Tregs more potently suppressed allograft rejection compared to their CD4 + CD25 + counterparts, supporting the hypothesis that CD8 + Tregs may represent a new and promising Treg family that can be targeted to prevent allograft rejection in the clinic. In this review, we summarize the progress in the field during the past 7-10 years and discuss CD8 + Treg phenotypes, mechanisms of action, and their potential clinical applications; particularly in composite tissue transplants in burn and trauma patients.

  18. A dominant role for the immunoproteasome in CD8+ T cell responses to murine cytomegalovirus.

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    Sarah Hutchinson

    Full Text Available Murine cytomegalovirus (MCMV is an important animal model of human cytomegalovirus (HCMV, a β-Herpesvirus that infects the majority of the world's population and causes disease in neonates and immunocompromised adults. CD8(+ T cells are a major part of the immune response to MCMV and HCMV. Processing of peptides for presentation to CD8(+ T cells may be critically dependent on the immunoproteasome, expression of which is affected by MCMV. However, the overall importance of the immunoproteasome in the generation of immunodominant peptides from MCMV is not known. We therefore examined the role of the immunoproteasome in stimulation of CD8(+ T cell responses to MCMV - both conventional memory responses and those undergoing long-term expansion or "inflation". We infected LMP7(-/- and C57BL/6 mice with MCMV or with newly-generated recombinant vaccinia viruses (rVVs encoding the immunodominant MCMV protein M45 in either full-length or epitope-only minigene form. We analysed CD8(+ T cell responses using intracellular cytokine stain (ICS and MHC Class I tetramer staining for a panel of MCMV-derived epitopes. We showed a critical role for immunoproteasome in MCMV affecting all epitopes studied. Interestingly we found that memory "inflating" epitopes demonstrate reduced immunoproteasome dependence compared to non-inflating epitopes. M45-specific responses induced by rVVs remain immunoproteasome-dependent. These results help to define a critical restriction point for CD8(+ T cell epitopes in natural cytomegalovirus (CMV infection and potentially in vaccine strategies against this and other viruses.

  19. Specific Control of Immunity by Regulatory CD8 T Cells

    Institute of Scientific and Technical Information of China (English)

    XiaoleiTang; TrevorRFSmith

    2005-01-01

    T lymphocytes with dedicated suppressor function (Treg) play a crucial role in the homeostatic control of immunity in the periphery. Several Treg phenotypes have now been identified in the CD4 and CD8 T cell populations, suggesting their down-regulatory function in both human and animal models of autoimmunity, transplantation and tumor immunity. Here we will focus on the CD8 Treg population and their ability to specifically inhibit a pathogenic autoimmune response. This review will detail the current advances in the knowledge of CD8 Treg in the context of antigen specificity, phenotype, MHC restriction, mechanism of action, and priming. Cellular & Molecular Immunology. 2005;2(1):11-19.

  20. HLA-A02:01-Restricted Epitopes Identified from the Herpes Simplex Virus Tegument Protein VP11/12 Preferentially Recall Polyfunctional Effector Memory CD8+ T Cells from Seropositive Asymptomatic Individuals and Protect “Humanized” HLA-A*02:01 Transgenic Mice Against Ocular Herpes

    Science.gov (United States)

    Srivastava, Ruchi; Khan, Arif A.; Spencer, Doran; Vahed, Hawa; Lopes, Patricia P.; Thai, Nhi Thi Uyen; Wang, Christine; Pham, Thanh T.; Huang, Jiawei; Scarfone, Vanessa M.; Nesburn, Anthony B.; Wechsler, Steven L.; BenMohamed, Lbachir

    2014-01-01

    The Herpes Simplex Virus type 1 virion tegument phosphoprotein 11/12 (HSV-1 VP11/12) is a major antigen targeted by CD8+ T cells from HSV-seropositive individuals. However, whether and which VP11/12-epitope-specific CD8+ T cells play a role in the “natural” protection seen in seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. In this study, we used multiple prediction computer-assisted algorithms to identify 10 potential HLA-A*02:01-restricted CD8+ T cell epitopes from the 716 amino acids sequence of VP11/12. Three out of ten epitopes exhibited high to moderate binding affinity to HLA-A*02:01 molecules. In ten sequentially studied HLA-A*02:01 positive and HSV-1-seropositive ASYMP individuals, the most frequent, robust and polyfunctional effector CD8+ T-cell responses, as assessed by a combination of tetramer frequency, granzyme B, granzyme K, perforin, CD107a/b cytotoxic degranulation, IFN-γ and multiplex cytokines assays, were predominantly directed against three epitopes: VP11/1266–74, VP11/12220–228 and VP11/12702–710. Interestingly, ASYMP individuals had significantly higher proportion of CD45RAlowCCR7lowCD44highCD62LlowCD27lowCD28lowCD8+ effector memory T cells (TEM) specific to the three epitopes, compared to symptomatic (SYMP) individuals (with a history of numerous episodes of recurrent ocular herpetic disease). Moreover, immunization of HLA-A*02:01 transgenic mice with the three ASYMP CD8+ TEM cell epitopes induced robust and polyfunctional epitope-specific CD8+ TEM cells that were associated with a strong protective immunity against ocular herpes infection and disease. Our findings outline phenotypic and functional features of protective HSV-specific CD8+ T cells that should guide the development of an effective T-cell-based herpes vaccine. PMID:25617474

  1. CD4+ T cell effects on CD8+ T cell location defined using bioluminescence.

    Directory of Open Access Journals (Sweden)

    Mitra Azadniv

    Full Text Available T lymphocytes of the CD8+ class are critical in delivering cytotoxic function and in controlling viral and intracellular infections. These cells are "helped" by T lymphocytes of the CD4+ class, which facilitate their activation, clonal expansion, full differentiation and the persistence of memory. In this study we investigated the impact of CD4+ T cells on the location of CD8+ T cells, using antibody-mediated CD4+ T cell depletion and imaging the antigen-driven redistribution of bioluminescent CD8+ T cells in living mice. We documented that CD4+ T cells influence the biodistribution of CD8+ T cells, favoring their localization to abdominal lymph nodes. Flow cytometric analysis revealed that this was associated with an increase in the expression of specific integrins. The presence of CD4+ T cells at the time of initial CD8+ T cell activation also influences their biodistribution in the memory phase. Based on these results, we propose the model that one of the functions of CD4+ T cell "help" is to program the homing potential of CD8+ T cells.

  2. Non-hematopoietic cells in lymph nodes drive memory CD8 T cell inflation during murine cytomegalovirus infection.

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    Nicole Torti

    2011-10-01

    Full Text Available During human and murine cytomegalovirus (MCMV infection an exceptionally large virus-specific CD8 T cell pool is maintained in the periphery lifelong. This anomalous response is only seen for specific subsets of MCMV-specific CD8 T cells which are referred to as 'inflationary T cells'. How memory CD8 T cell inflation is induced and maintained is unclear, though their activated phenotype strongly suggests an involvement of persistent antigen encounter during MCMV latency. To dissect the cellular and molecular requirements for memory CD8 T cell inflation, we have generated a transgenic mouse expressing an MHC class I-restricted T cell receptor specific for an immunodominant inflationary epitope of MCMV. Through a series of adoptive transfer experiments we found that memory inflation was completely dependent on antigen presentation by non-hematopoietic cells, which are also the predominant site of MCMV latency. In particular, non-hematopoietic cells selectively induced robust proliferation of inflationary CD8 T cells in lymph nodes, where a majority of the inflationary CD8 T cells exhibit a central-memory phenotype, but not in peripheral tissues, where terminally differentiated inflationary T cells accumulate. These results indicate that continuous restimulation of central memory CD8 T cells in the lymph nodes by infected non-hematopoietic cells ensures the maintenance of a functional effector CD8 T pool in the periphery, providing protection against viral reactivation events.

  3. Incomplete effector/memory differentiation of antigen-primed CD8+ T cells in gene gun DNA-vaccinated mice

    DEFF Research Database (Denmark)

    Bartholdy, Christina; Stryhn, Anette; Hansen, Nils Jacob Vest;

    2003-01-01

    DNA vaccination is an efficient way to induce CD8+ T cell memory, but it is still unclear to what extent such memory responses afford protection in vivo. To study this, we induced CD8+ memory responses directed towards defined viral epitopes, using DNA vaccines encoding immunodominant MHC class I...

  4. Prolonged activation of virus-specific CD8+T cells after acute B19 infection.

    Directory of Open Access Journals (Sweden)

    2005-12-01

    Full Text Available BACKGROUND: Human parvovirus B19 (B19 is a ubiquitous and clinically significant pathogen, causing erythema infectiosum, arthropathy, transient aplastic crisis, and intrauterine fetal death. The phenotype of CD8+ T cells in acute B19 infection has not been studied previously. METHODS AND FINDINGS: The number and phenotype of B19-specific CD8+ T cell responses during and after acute adult infection was studied using HLA-peptide multimeric complexes. Surprisingly, these responses increased in magnitude over the first year post-infection despite resolution of clinical symptoms and control of viraemia, with T cell populations specific for individual epitopes comprising up to 4% of CD8+ T cells. B19-specific T cells developed and maintained an activated CD38+ phenotype, with strong expression of perforin and CD57 and downregulation of CD28 and CD27. These cells possessed strong effector function and intact proliferative capacity. Individuals tested many years after infection exhibited lower frequencies of B19-specific cytotoxic T lymphocytes, typically 0.05%-0.5% of CD8+ T cells, which were perforin, CD38, and CCR7 low. CONCLUSION: This is the first example to our knowledge of an "acute" human viral infection inducing a persistent activated CD8+ T cell response. The likely explanation--analogous to that for cytomegalovirus infection--is that this persistent response is due to low-level antigen exposure. CD8+ T cells may contribute to the long-term control of this significant pathogen and should be considered during vaccine development.

  5. A Numerically Subdominant CD8 T Cell Response to Matrix Protein of Respiratory Syncytial Virus Controls Infection with Limited Immunopathology.

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    Jie Liu

    2016-03-01

    Full Text Available CD8 T cells are involved in pathogen clearance and infection-induced pathology in respiratory syncytial virus (RSV infection. Studying bulk responses masks the contribution of individual CD8 T cell subsets to protective immunity and immunopathology. In particular, the roles of subdominant responses that are potentially beneficial to the host are rarely appreciated when the focus is on magnitude instead of quality of response. Here, by evaluating CD8 T cell responses in CB6F1 hybrid mice, in which multiple epitopes are recognized, we found that a numerically subdominant CD8 T cell response against DbM187 epitope of the virus matrix protein expressed high avidity TCR and enhanced signaling pathways associated with CD8 T cell effector functions. Each DbM187 T effector cell lysed more infected targets on a per cell basis than the numerically dominant KdM282 T cells, and controlled virus replication more efficiently with less pulmonary inflammation and illness than the previously well-characterized KdM282 T cell response. Our data suggest that the clinical outcome of viral infections is determined by the integrated functional properties of a variety of responding CD8 T cells, and that the highest magnitude response may not necessarily be the best in terms of benefit to the host. Understanding how to induce highly efficient and functional T cells would inform strategies for designing vaccines intended to provide T cell-mediated immunity.

  6. CD8 T cell response maturation defined by anentropic specificity and repertoire depth correlates with SIVΔnef-induced protection.

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    Sama Adnan

    2015-02-01

    Full Text Available The live attenuated simian immunodeficiency virus (LASIV vaccine SIVΔnef is one of the most effective vaccines in inducing protection against wild-type lentiviral challenge, yet little is known about the mechanisms underlying its remarkable protective efficacy. Here, we exploit deep sequencing technology and comprehensive CD8 T cell epitope mapping to deconstruct the CD8 T cell response, to identify the regions of immune pressure and viral escape, and to delineate the effect of epitope escape on the evolution of the CD8 T cell response in SIVΔnef-vaccinated animals. We demonstrate that the initial CD8 T cell response in the acute phase of SIVΔnef infection is mounted predominantly against more variable epitopes, followed by widespread sequence evolution and viral escape. Furthermore, we show that epitope escape expands the CD8 T cell repertoire that targets highly conserved epitopes, defined as anentropic specificity, and generates de novo responses to the escaped epitope variants during the vaccination period. These results correlate SIVΔnef-induced protection with expanded anentropic specificity and increased response depth. Importantly, these findings render SIVΔnef, long the gold standard in HIV/SIV vaccine research, as a proof-of-concept vaccine that highlights the significance of the twin principles of anentropic specificity and repertoire depth in successful vaccine design.

  7. Identification of Theileria lestoquardi Antigens Recognized by CD8+ T Cells

    Science.gov (United States)

    Ngugi, Daniel; Lizundia, Regina; Hostettler, Isabel; Woods, Kerry; Ballingall, Keith; MacHugh, Niall D.; Morrison, W. Ivan; Weir, Willie; Shiels, Brian; Werling, Dirk

    2016-01-01

    As part of an international effort to develop vaccines for Theileria lestoquardi, we undertook a limited screen to test T. lestoquardi orthologues of antigens recognised by CD8+ T lymphocyte responses against T. annulata and T. parva in cattle. Five MHC defined sheep were immunized by live T. lestoquardi infection and their CD8+ T lymphocyte responses determined. Thirteen T. lestoquardi orthologues of T. parva and T. annulata genes, previously shown to be targets of CD8+ T lymphocyte responses of immune cattle, were expressed in autologous fibroblasts and screened for T cell recognition using an IFNγ assay. Genes encoding T. lestoquardi antigens Tl8 (putative cysteine proteinase, 349 aa) or Tl9 (hypothetical secreted protein, 293 aa) were recognise by T cells from one animal that displayed a unique MHC class I genotype. Antigenic 9-mer peptide epitopes of Tl8 and Tl9 were identified through peptide scans using CD8+ T cells from the responding animal. These experiments identify the first T. lestoquardi antigens recognised by CD8+ T cell responses linked to specific MHC class I alleles. PMID:27611868

  8. A Human Trypanosome Suppresses CD8+ T Cell Priming by Dendritic Cells through the Induction of Immune Regulatory CD4+ Foxp3+ T Cells

    Science.gov (United States)

    Ersching, Jonatan; Basso, Alexandre Salgado; Kalich, Vera Lucia Garcia; Bortoluci, Karina Ramalho

    2016-01-01

    Although CD4+ Foxp3+ T cells are largely described in the regulation of CD4+ T cell responses, their role in the suppression of CD8+ T cell priming is much less clear. Because the induction of CD8+ T cells during experimental infection with Trypanosoma cruzi is remarkably delayed and suboptimal, we raised the hypothesis that this protozoan parasite actively induces the regulation of CD8+ T cell priming. Using an in vivo assay that eliminated multiple variables associated with antigen processing and dendritic cell activation, we found that injection of bone marrow-derived dendritic cells exposed to T. cruzi induced regulatory CD4+ Foxp3+ T cells that suppressed the priming of transgenic CD8+ T cells by peptide-loaded BMDC. This newly described suppressive effect on CD8+ T cell priming was independent of IL-10, but partially dependent on CTLA-4 and TGF-β. Accordingly, depletion of Foxp3+ cells in mice infected with T. cruzi enhanced the response of epitope-specific CD8+ T cells. Altogether, our data uncover a mechanism by which T. cruzi suppresses CD8+ T cell responses, an event related to the establishment of chronic infections. PMID:27332899

  9. A highly restricted T-cell receptor dominates the CD8+ T-cell response to parvovirus B19 infection in HLA-A*2402-positive individuals

    DEFF Research Database (Denmark)

    Kasprowicz, V; Jeffery, K; Broliden, K;

    2006-01-01

    Six of seven HLA-A*2402-positive individuals with acute parvovirus B19 infections made vigorous CD8-positive cytotoxic T-cell (CTL) responses to the viral epitope FYTPLADQF. All responders showed highly focused T-cell receptor (TCR) usage, using almost exclusively BV5.1. The BV5.1 TCR dominated...

  10. Decline of influenza-specific CD8+ T cell repertoire in healthy geriatric donors

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    Ramachandra Lakshmi

    2011-08-01

    Full Text Available Abstract Background While influenza vaccination results in protective antibodies against primary infections, clearance of infection is primarily mediated through CD8+ T cells. Studying the CD8+ T cell response to influenza epitopes is crucial in understanding the disease associated morbidity and mortality especially in at risk populations such as the elderly. We compared the CD8+ T cell response to immunodominant and subdominant influenza epitopes in HLA-A2+ control, adult donors, aged 21-42, and in geriatric donors, aged 65 and older. Results We used a novel artificial Antigen Presenting Cell (aAPC based stimulation assay to reveal responses that could not be detected by enzyme-linked immunosorbent spot (ELISpot. 14 younger control donors and 12 geriatric donors were enrolled in this study. The mean number of influenza-specific subdominant epitopes per control donor detected by ELISpot was only 1.4 while the mean detected by aAPC assay was 3.3 (p = 0.0096. Using the aAPC assay, 92% of the control donors responded to at least one subdominant epitopes, while 71% of control donors responded to more than one subdominant influenza-specific response. 66% of geriatric donors lacked a subdominant influenza-specific response and 33% of geriatric donors responded to only 1 subdominant epitope. The difference in subdominant response between age groups is statistically significant (p = 0.0003. Conclusion Geriatric donors lacked the broad, multi-specific response to subdominant epitopes seen in the control donors. Thus, we conclude that aging leads to a decrease in the subdominant influenza-specific CTL responses which may contribute to the increased morbidity and mortality in older individuals.

  11. Targeted suppression of autoreactive CD8+ T-cell activation using blocking anti-CD8 antibodies

    Science.gov (United States)

    Clement, Mathew; Pearson, James A.; Gras, Stephanie; van den Berg, Hugo A.; Lissina, Anya; Llewellyn-Lacey, Sian; Willis, Mark D.; Dockree, Tamsin; McLaren, James E.; Ekeruche-Makinde, Julia; Gostick, Emma; Robertson, Neil P.; Rossjohn, Jamie; Burrows, Scott R.; Price, David A.; Wong, F. Susan; Peakman, Mark; Skowera, Ania; Wooldridge, Linda

    2016-01-01

    CD8+ T-cells play a role in the pathogenesis of autoimmune diseases such as multiple sclerosis and type 1 diabetes. However, drugs that target the entire CD8+ T-cell population are not desirable because the associated lack of specificity can lead to unwanted consequences, most notably an enhanced susceptibility to infection. Here, we show that autoreactive CD8+ T-cells are highly dependent on CD8 for ligand-induced activation via the T-cell receptor (TCR). In contrast, pathogen-specific CD8+ T-cells are relatively CD8-independent. These generic differences relate to an intrinsic dichotomy that segregates self-derived and exogenous antigen-specific TCRs according to the monomeric interaction affinity with cognate peptide-major histocompatibility complex class I (pMHCI). As a consequence, “blocking” anti-CD8 antibodies can suppress autoreactive CD8+ T-cell activation in a relatively selective manner. These findings provide a rational basis for the development and in vivo assessment of novel therapeutic strategies that preferentially target disease-relevant autoimmune responses within the CD8+ T-cell compartment. PMID:27748447

  12. Origin of CD8+ Effector and Memory T Cell Subsets

    Institute of Scientific and Technical Information of China (English)

    Christian Stemberger; Michael Neuenhahn; Veit R.Buchholz; Dirk H.Busch

    2007-01-01

    It is well accepted that CD8+ T cells play a pivotal role in providing protection against infection with intracellular pathogens and some tumors. In many cases protective immunity is maintained for long periods of time (immunological memory). Over the past years, it has become evident that in order to fulfill these multiple tasks,distinct subsets of effector and memory T cells have to be generated. Until today, however, little is known about the underlying mechanisms of subset differentiation and the timing of lineage fate decisions. In this context, it is of special importance to determine at which level of clonal expansion functional and phenotypical heterogeneity is achieved. Different models for T cell subset diversification have been proposed; these differ mainly in the time point during priming and clonal expansion (prior, during, or beyond the first cell division) when differentiation programs are induced. Recently developed single-cell adoptive transfer technology has allowed us to demonstrate that individual precursor cell still bears the full plasticity to develop into a plethora different T cell subsets. This observation targets the shaping of T cell subset differentiation towards factors that are still operative beyond the first cell division. These findings have important implications for vaccine development, as the modulation of differentiation patterns towards distinct subsets could become a powerful strategy to enhance the efficacy and quality of vaccines.

  13. CD8αα expression marks terminally differentiated human CD8+ T cells expanded in chronic viral infection

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    Lucy Jane Walker

    2013-08-01

    Full Text Available The T cell co-receptor CD8αβ enhances T cell sensitivity to antigen, however studies indicate CD8αα has the converse effect and acts as a co-repressor. Using a combination of Thymic Leukaemia antigen (TL tetramer, which directly binds CD8αα, anti-CD161 and anti-Vα7.2 antibodies we have been able for the first time to clearly define CD8αα expression on human CD8 T cells subsets. In healthy controls CD8αα is most highly expressed by CD161 bright (CD161++ mucosal associated invariant T (MAIT cells, with CD8αα expression highly restricted to the TCR Vα7.2+ cells of this subset. We also identified CD8αα-expressing populations within the CD161 mid (CD161+ and negative (CD161- non-MAIT CD8 T cell subsets and show TL-tetramer binding to correlate with expression of CD8β at low levels in the context of maintained CD8α expression (CD8α+CD8βlow. In addition, we found CD161-CD8α+CD8βlow populations to be significantly expanded in the peripheral blood of HIV-1 and hepatitis B (mean of 47% and 40% of CD161- T cells respectively infected individuals. Such CD8αα expressing T cells are an effector-memory population (CD45RA-, CCR7-, CD62L- that express markers of activation and maturation (HLA-DR+, CD28-, CD27-, CD57+ and are functionally distinct, expressing greater levels of TNF-α and IFN-γ on stimulation and perforin at rest than their CD8α+CD8βhigh counterparts. Antigen-specific T cells in HLA-B*4201+HIV-1 infected patients are found within both the CD161-CD8α+CD8βhigh and CD161-CD8α+CD8βlow populations. Overall we have clearly defined CD8αα expressing human T cell subsets using the TL-tetramer, and have demonstrated CD161-CD8α+CD8βlow populations, highly expanded in disease settings, to co-express CD8αβ and CD8αα. Co-expression of CD8αα on CD8αβ T cells may impact on their overall function in-vivo and contribute to the distinctive phenotype of highly differentiated populations in HBV and HIV-1 infection.

  14. Distribution, characterization, and induction of CD8+ regulatory T cells and IL-17-producing CD8+ T cells in nasopharyngeal carcinoma

    OpenAIRE

    Li Jiang; Huang Zhou-Feng; Xiong Geng; Mo Hao-Yuan; Qiu Fang; Mai Hai-Qiang; Chen Qiu-Yan; He Jia; Chen Shu-peng; Zheng Li-Min; Qian Chao-Nan; Zeng Yi-Xin

    2011-01-01

    Abstract Background CD8+ effector cells often have an antitumor function in patients with cancer. However, CD8+Foxp3+ regulatory T cells (Tcregs) and interleukin (IL)-17-producing CD8+ T cells (Tc17 cells) also derive from the CD8+ T cell lineage. Their role in the antitumor response remains largely unknown. In the present study, we aimed to investigate the distribution, characterization, and generation of CD8+ Tcregs and Tc17 cells in NPC patients. Methods Peripheral blood and tumor biopsy t...

  15. Full-breadth analysis of CD8+ T-cell responses in acute hepatitis C virus infection and early therapy.

    Science.gov (United States)

    Lauer, Georg M; Lucas, Michaela; Timm, Joerg; Ouchi, Kei; Kim, Arthur Y; Day, Cheryl L; Schulze Zur Wiesch, Julian; Paranhos-Baccala, Glaucia; Sheridan, Isabelle; Casson, Deborah R; Reiser, Markus; Gandhi, Rajesh T; Li, Bin; Allen, Todd M; Chung, Raymond T; Klenerman, Paul; Walker, Bruce D

    2005-10-01

    Multispecific CD8(+) T-cell responses are thought to be important for the control of acute hepatitis C virus (HCV) infection, but to date little information is actually available on the breadth of responses at early time points. Additionally, the influence of early therapy on these responses and their relationships to outcome are controversial. To investigate this issue, we performed comprehensive analysis of the breadth and frequencies of virus-specific CD8(+) T-cell responses on the single epitope level in eight acutely infected individuals who were all started on early therapy. During the acute phase, responses against up to five peptides were identified. During therapy, CD8(+) T-cell responses decreased rather than increased as virus was controlled, and no new specificities emerged. A sustained virological response following completion of treatment was independent of CD8(+) T-cell responses, as well as CD4(+) T-cell responses. Rapid recrudescence also occurred despite broad CD8(+) T-cell responses. Importantly, in vivo suppression of CD3(+) T cells using OKT3 in one subject did not result in recurrence of viremia. These data suggest that broad CD8(+) T-cell responses alone may be insufficient to contain HCV replication, and also that early therapy is effective independent of such responses. PMID:16189000

  16. The administration route is decisive for the ability of the vaccine adjuvant CAF09 to induce antigen-specific CD8(+) T-cell responses

    DEFF Research Database (Denmark)

    Schmidt, Signe Tandrup; Khadke, Swapnil; Korsholm, Karen Smith;

    2016-01-01

    A prerequisite for vaccine-mediated induction of CD8(+) T-cell responses is the targeting of dendritic cell (DC) subsets specifically capable of cross-presenting antigen epitopes to CD8(+) T cells. Administration of a number of cationic adjuvants via the intraperitoneal (i.p.) route has been show...

  17. Peripheral canine CD4(+)CD8(+) double-positive T cells - unique amongst others.

    Science.gov (United States)

    von Buttlar, Heiner; Bismarck, Doris; Alber, Gottfried

    2015-12-15

    T lymphocytes co-expressing CD4 and CD8 ("double-positive T cells") are commonly associated with a thymic developmental stage of T cells. Their first description in humans and pigs as extrathymic T cells with a memory phenotype almost 30 years ago came as a surprise. Meanwhile peripheral double-positive T cells have been described in a growing number of different species. In this review we highlight novel data from our very recent studies on canine peripheral double-positive T cells which point to unique features of double-positive T cells in the dog. In contrast to porcine CD4(+)CD8(+) T cells forming a homogenous cellular population based on their expression of CD4 and CD8α, canine CD4(+)CD8(+) T cells can be divided into three different cellular subsets with distinct expression levels of CD4 and CD8α. Double-positive T cells expressing CD8β are present in humans and dogs but absent in swine. Moreover, canine CD4(+)CD8(+) T cells can not only develop from CD4(+) single-positive T cells but also from CD8(+) single-positive T cells. Together, this places canine CD4(+)CD8(+) T cells closer to their human than porcine counterparts since human double-positive T cells also appear to be heterogeneous in their CD4 and CD8α expression and have both CD4(+) and CD8(+) T cells as progenitor cells. However, CD4(+) single-positive T cells are the more potent progenitors for canine double-positive T cells, whereas CD8(+) single-positive T cells are more potent progenitors for human double-positive T cells. Canine double-positive T cells have an activated phenotype and may have as yet unrecognized roles in vivo in immunity to infection or in inflammatory diseases such as chronic infection, autoimmunity, allergy, or cancer.

  18. Peptide pool immunization and CD8+ T cell reactivity

    DEFF Research Database (Denmark)

    Rasmussen, Susanne B; Harndahl, Mikkel N; Buus, Anette Stryhn;

    2013-01-01

    Mice were immunized twice with a pool of five peptides selected among twenty 8-9-mer peptides for their ability to form stable complexes at 37°C with recombinant H-2K(b) (half-lives 10-15h). Vaccine-induced immunity of splenic CD8(+) T cells was studied in a 24h IFNγ Elispot assay. Surprisingly......, IFNγ spot-formation was observed without addition of peptide to the assay culture at 3 weeks and 3 months after immunization. To clarify if IFNγ spot formation in the absence of peptide exposure ex vivo is caused by the peptide-pool per se, mice were immunized with single peptides. Three of the five...

  19. Killing of targets by effector CD8 T cells in the mouse spleen follows the law of mass action

    Energy Technology Data Exchange (ETDEWEB)

    Ganusov, Vitaly V [Los Alamos National Laboratory

    2009-01-01

    In contrast with antibody-based vaccines, it has been difficult to measure the efficacy of T cell-based vaccines and to correlate the efficacy of CD8 T cell responses with protection again viral infections. In part, this difficulty is due to poor understanding of the in vivo efficacy of CD8 T cells produced by vaccination. Using a: recently developed experimental method of in vivo cytotoxicity we have investigated quantitative aspects of killing of peptide-pulsed targets by effector and memory CD8 T cells, specific to three epitopes of lymphocytic choriomeningitis virus (LCMV), in the mouse spleen. By analyzing data on killing of targets with varying number of epitope-specific effector and memory CD8 T cells, we find that killing of targets by effectors follows the law of mass-action, that is the death rate of peptide-pulsed targets is proportional to the frequency of CTLs in the spleen. In contrast, killing of targets by memory CD8 T cells does not follow the mass action law because the death rate of targets saturates at high frequencies of memory CD8 T cells. For both effector and memory cells, we also find little support for the killing term that includes the decrease of the death rate of targets with target cell density. Interestingly, our analysis suggests that at low CD8 T cell frequencies, memory CD8 T cells on the per capita basis are more efficient at killing peptide-pulsed targets than effectors, but at high frequencies, effectors are more efficient killers than memory T cells. Comparison of the estimated killing efficacy of effector T cells with the value that is predicted from theoretical physics and based on motility of T cells in lymphoid tissues, suggests that limiting step in the killing of peptide-pulsed targets is delivering the lethal hit and not finding the target. Our results thus form a basis for quantitative understanding of the process of killing of virus-infected cells by T cell responses in tissues and can be used to correlate the

  20. Requirements for Peptide-induced T Cell Receptor Downregulation on Naive CD8+ T Cells

    OpenAIRE

    Cai, Zeling; Kishimoto, Hidehiro; Brunmark, Anders; Jackson, Michael R.; Peterson, Per A.; Sprent, Jonathan

    1997-01-01

    The requirements for inducing downregulation of α/β T cell receptor (TCR) molecules on naive major histocompatibility complex class I–restricted T cells was investigated with 2C TCR transgenic mice and defined peptides as antigen. Confirming previous results, activation of 2C T cells in response to specific peptides required CD8 expression on the responder cells and was heavily dependent upon costimulation provided by either B7-1 or ICAM-1 on antigen-presenting cells (APC). These stringent re...

  1. Involvement and prognosis value of CD8(+) T cells in giant cell arteritis.

    Science.gov (United States)

    Samson, Maxime; Ly, Kim Heang; Tournier, Benjamin; Janikashvili, Nona; Trad, Malika; Ciudad, Marion; Gautheron, Alexandrine; Devilliers, Hervé; Quipourt, Valérie; Maurier, François; Meaux-Ruault, Nadine; Magy-Bertrand, Nadine; Manckoundia, Patrick; Ornetti, Paul; Maillefert, Jean-Francis; Besancenot, Jean-François; Ferrand, Christophe; Mesturoux, Laura; Labrousse, François; Fauchais, Anne-Laure; Saas, Philippe; Martin, Laurent; Audia, Sylvain; Bonnotte, Bernard

    2016-08-01

    CD8(+) T cells participate in the pathogenesis of some vasculitides. However, little is known about their role in Giant Cell Arteritis (GCA). This study was conducted to investigate CD8(+) T cell involvement in the pathogenesis of GCA. Analyses were performed at diagnosis and after 3 months of glucocorticoid treatment in 34 GCA patients and 26 age-matched healthy volunteers. Percentages of CD8(+) T-cell subsets, spectratype analysis of the TCR Vβ families of CD8(+) T cells, levels of cytokines and chemokines and immunohistochemistry of temporal artery biopsies (TAB) were assessed. Among total CD8(+) T cells, percentages of circulating cytotoxic CD8 T lymphocytes (CTL, CD3(+)CD8(+)perforin(+)granzymeB(+)), Tc17 (CD3(+)CD8(+)IL-17(+)), CD63(+)CD8(+) T cells and levels of soluble granzymes A and B were higher in patients than in controls, whereas the percentage of Tc1 cells (CD3(+)CD8(+)IFN-γ(+)) was similar. Moreover, CD8(+) T cells displayed a restricted TCR repertoire in GCA patients. Percentages of circulating CTL, Tc17 and soluble levels of granzymes A and B decreased after treatment. CXCR3 expression on CD8(+) T cells and its serum ligands (CXCL9, -10, -11) were higher in patients. Analyses of TAB revealed high expression of CXCL9 and -10 associated with infiltration by CXCR3(+)CD8(+) T cells expressing granzyme B and TiA1. The intensity of the CD8 T-cell infiltrate in TAB was predictive of the severity of the disease. This study demonstrates the implication and the prognostic value of CD8(+) T-cells in GCA and suggests that CD8(+) T-cells are recruited within the vascular wall through an interaction between CXCR3 and its ligands. PMID:27236507

  2. Tumor-specific CD4+ T cells maintain effector and memory tumor-specific CD8+ T cells

    Science.gov (United States)

    Church, Sarah E; Jensen, Shawn M; Antony, Paul A; Restifo, Nicholas P; Fox, Bernard A

    2014-01-01

    Immunotherapies that augment antitumor T cells have had recent success for treating patients with cancer. Here we examined whether tumor-specific CD4+ T cells enhance CD8+ T-cell adoptive immunotherapy in a lymphopenic environment. Our model employed physiological doses of tyrosinase-related protein 1-specific CD4+ transgenic T cells-CD4+ T cells and pmel-CD8+ T cells that when transferred individually were subtherapeutic; however, when transferred together provided significant (p ≤ 0.001) therapeutic efficacy. Therapeutic efficacy correlated with increased numbers of effector and memory CD8+ T cells with tumor-specific cytokine expression. When combined with CD4+ T cells, transfer of total (naïve and effector) or effector CD8+ T cells were highly effective, suggesting CD4+ T cells can help mediate therapeutic effects by maintaining function of activated CD8+ T cells. In addition, CD4+ T cells had a pronounced effect in the early posttransfer period, as their elimination within the first 3 days significantly (p < 0.001) reduced therapeutic efficacy. The CD8+ T cells recovered from mice treated with both CD8+ and CD4+ T cells had decreased expression of PD-1 and PD-1-blockade enhanced the therapeutic efficacy of pmel-CD8 alone, suggesting that CD4+ T cells help reduce CD8+ T-cell exhaustion. These data support combining immunotherapies that elicit both tumor-specific CD4+ and CD8+ T cells for treatment of patients with cancer. PMID:24114780

  3. Adaptation of CD8 T cell responses to changing HIV-1 sequences in a cohort of HIV-1 infected individuals not selected for a certain HLA allele.

    Directory of Open Access Journals (Sweden)

    Julia Roider

    Full Text Available HIV evades CD8 T cell mediated pressure by viral escape mutations in targeted CD8 T cell epitopes. A viral escape mutation can lead to a decline of the respective CD8 T cell response. Our question was what happened after the decline of a CD8 T cell response and - in the case of viral escape - if a new CD8 T cell response towards the mutated antigen could be generated in a population not selected for certain HLA alleles. We studied 19 antiretroviral-naïve HIV-1 infected individuals with different disease courses longitudinally. A median number of 12 (range 2-24 CD8 T cell responses towards Gag and Nef were detected per study subject. A total of 30 declining CD8 T cell responses were studied in detail and viral sequence analyses showed amino acid changes in 25 (83% of these. Peptide titration assays and definition of optimal CD8 T cell epitopes revealed 12 viral escape mutations with one de-novo response (8%. The de-novo response, however, showed less effector functions than the original CD8 T cell response. In addition we identified 4 shifts in immunodominance. For one further shift in immunodominance, the mutations occurred outside the optimal epitope and might represent processing changes. Interestingly, four adaptations to the virus (the de-novo response and 3 shifts in immunodominance occurred in the group of chronically infected progressors. None of the subjects with adaptation to the changing virus carried the HLA alleles B57, B*58:01 or B27. Our results show that CD8 T cell responses adapt to the mutations of HIV. However it was limited to only 20% (5 out of 25 of the epitopes with viral sequence changes in a cohort not expressing protective HLA alleles.

  4. Adaptation of CD8 T cell responses to changing HIV-1 sequences in a cohort of HIV-1 infected individuals not selected for a certain HLA allele.

    Science.gov (United States)

    Roider, Julia; Kalteis, Anna-Lena; Vollbrecht, Thomas; Gloning, Lisa; Stirner, Renate; Henrich, Nadja; Bogner, Johannes R; Draenert, Rika

    2013-01-01

    HIV evades CD8 T cell mediated pressure by viral escape mutations in targeted CD8 T cell epitopes. A viral escape mutation can lead to a decline of the respective CD8 T cell response. Our question was what happened after the decline of a CD8 T cell response and - in the case of viral escape - if a new CD8 T cell response towards the mutated antigen could be generated in a population not selected for certain HLA alleles. We studied 19 antiretroviral-naïve HIV-1 infected individuals with different disease courses longitudinally. A median number of 12 (range 2-24) CD8 T cell responses towards Gag and Nef were detected per study subject. A total of 30 declining CD8 T cell responses were studied in detail and viral sequence analyses showed amino acid changes in 25 (83%) of these. Peptide titration assays and definition of optimal CD8 T cell epitopes revealed 12 viral escape mutations with one de-novo response (8%). The de-novo response, however, showed less effector functions than the original CD8 T cell response. In addition we identified 4 shifts in immunodominance. For one further shift in immunodominance, the mutations occurred outside the optimal epitope and might represent processing changes. Interestingly, four adaptations to the virus (the de-novo response and 3 shifts in immunodominance) occurred in the group of chronically infected progressors. None of the subjects with adaptation to the changing virus carried the HLA alleles B57, B*58:01 or B27. Our results show that CD8 T cell responses adapt to the mutations of HIV. However it was limited to only 20% (5 out of 25) of the epitopes with viral sequence changes in a cohort not expressing protective HLA alleles.

  5. Bystander CD8 T-Cell-Mediated Demyelination is Interferon-γ-Dependent in a Coronavirus Model of Multiple Sclerosis

    OpenAIRE

    Dandekar, Ajai A.; Anghelina, Daniela; Perlman, Stanley

    2004-01-01

    Mice infected with the coronavirus mouse hepatitis virus, strain JHM (JHM) develop a disease that shares many histological characteristics with multiple sclerosis. We previously demonstrated that JHM-infected mice that only have CD8 T cells specific for an epitope not in the virus develop demyelination on specific activation of these cells. Herein we show that this process of bystander T-cell-mediated demyelination is interferon-γ (IFN-γ)-dependent. The absence of IFN-γ abrogated demyelinatio...

  6. Self-assembling peptide for co-delivery of HIV-1 CD8+ T cells epitope and Toll-like receptor 7/8 agonists R848 to induce maturation of monocyte derived dendritic cell and augment polyfunctional cytotoxic T lymphocyte (CTL) response.

    Science.gov (United States)

    Ding, Yong; Liu, Jun; Lu, Sheng; Igweze, Justice; Xu, Wen; Kuang, Da; Zealey, Chris; Liu, Daheng; Gregor, Alex; Bozorgzad, Ardalan; Zhang, Lei; Yue, Elizabeth; Mujib, Shariq; Ostrowski, Mario; Chen, P

    2016-08-28

    Peptide based vaccine that incorporates one or several highly conserved CD8+ T cells epitopes to induce potent cytotoxic T lymphocyte (CTL) response is desirable for some infectious diseases, such as HIV-1 (human immunodeficiency virus-1), and cancers. However, the CD8+ T cells epitope is often weakly immunogenic, and thus requires a specific adjuvant or delivery system to enhance the efficiency. Here we investigated the use of self-assembling peptide EAK16-II based platform to achieve the co-delivery of CD8+ T cells epitope and TLR7/8 agonists (R848 or R837) for augmenting DCs maturation and HIV-1 specific CTL response. HIV-1 CTL epitope SL9 was conjugated with EAK16-II to obtain SL9-EAK16-II, which further spontaneously co-assembled with R848 or R837 in aqueous solution, forming co-assembled nanofibers. Fluorescence spectra and calorimetrical titration revealed the interaction between SL9-EAK16-II assemblies and R848 or R837 via hydrogen bonding and hydrophobic interaction, with the binding affinity (dissociation constant Kd) of 0.62μM or 0.53μM, respectively. Ex vivo generated DCs from HIV-1+ patients pulsed with the SL9-EAK16-II/R848 nanofibers stimulated significantly more polyfunctional SL9 specific CTLs, compared to the DCs pulsed with SL9 alone or the mixture of SL9 and TLR agonist. Furthermore, the nanofibers elicited stronger SL9 specific CTL response in vaccinated mice. Our findings suggest the self-assembling peptide EAK16-II might be used as a new delivery system for peptide based vaccines. PMID:27297778

  7. Temporal Dynamics of CD8+ T Cell Effector Responses during Primary HIV Infection

    Science.gov (United States)

    Demers, Korey R.; Makedonas, George; Buggert, Marcus; Eller, Michael A.; Ratcliffe, Sarah J.; Goonetilleke, Nilu; Li, Chris K.; Eller, Leigh Anne; Rono, Kathleen; Maganga, Lucas; Nitayaphan, Sorachai; Kibuuka, Hannah; Routy, Jean-Pierre; Slifka, Mark K.; Haynes, Barton F.; Bernard, Nicole F.; Robb, Merlin L.; Betts, Michael R.

    2016-01-01

    The loss of HIV-specific CD8+ T cell cytolytic function is a primary factor underlying progressive HIV infection, but whether HIV-specific CD8+ T cells initially possess cytolytic effector capacity, and when and why this may be lost during infection, is unclear. Here, we assessed CD8+ T cell functional evolution from primary to chronic HIV infection. We observed a profound expansion of perforin+ CD8+ T cells immediately following HIV infection that quickly waned after acute viremia resolution. Selective expression of the effector-associated transcription factors T-bet and eomesodermin in cytokine-producing HIV-specific CD8+ T cells differentiated HIV-specific from bulk memory CD8+ T cell effector expansion. As infection progressed expression of perforin was maintained in HIV-specific CD8+ T cells with high levels of T-bet, but not necessarily in the population of T-betLo HIV-specific CD8+ T cells that expand as infection progresses. Together, these data demonstrate that while HIV-specific CD8+ T cells in acute HIV infection initially possess cytolytic potential, progressive transcriptional dysregulation leads to the reduced CD8+ T cell perforin expression characteristic of chronic HIV infection. PMID:27486665

  8. Protective antibody and CD8+ T-cell responses to the Plasmodium falciparum circumsporozoite protein induced by a nanoparticle vaccine.

    Directory of Open Access Journals (Sweden)

    Stephen A Kaba

    Full Text Available BACKGROUND: The worldwide burden of malaria remains a major public health problem due, in part, to the lack of an effective vaccine against the Plasmodium falciparum parasite. An effective vaccine will most likely require the induction of antigen specific CD8(+ and CD4(+ T-cells as well as long-lasting antibody responses all working in concert to eliminate the infection. We report here the effective modification of a self-assembling protein nanoparticle (SAPN vaccine previously proven effective in control of a P. berghei infection in a rodent model to now present B- and T-cell epitopes of the human malaria parasite P. falciparum in a platform capable of being used in human subjects. METHODOLOGY/PRINCIPAL FINDINGS: To establish the basis for a SAPN-based vaccine, B- and CD8(+ T-cell epitopes from the P. falciparum circumsporozoite protein (PfCSP and the universal CD4 T-helper epitope PADRE were engineered into a versatile small protein (∼125 amino acids that self-assembles into a spherical nanoparticle repetitively displaying the selected epitopes. P. falciparum epitope specific immune responses were evaluated in mice using a transgenic P. berghei malaria parasite of mice expressing the human malaria full-length P. falciparum circumsporozoite protein (Tg-Pb/PfCSP. We show that SAPN constructs, delivered in saline, can induce high-titer, long-lasting (1 year protective antibody and poly-functional (IFNγ(+, IL-2(+ long-lived central memory CD8(+ T-cells. Furthermore, we demonstrated that these Ab or CD8(+ T-cells can independently provide sterile protection against a lethal challenge of the transgenic parasites. CONCLUSION: The SAPN construct induces long-lasting antibody and cellular immune responses to epitope specific sequences of the P. falciparum circumsporozoite protein (PfCSP and prevents infection in mice by a transgenic P. berghei parasite displaying the full length PfCSP.

  9. Avian Influenza Viruses, Inflammation, and CD8+ T Cell Immunity

    Science.gov (United States)

    Wang, Zhongfang; Loh, Liyen; Kedzierski, Lukasz; Kedzierska, Katherine

    2016-01-01

    Avian influenza viruses (AIVs) circulate naturally in wild aquatic birds, infect domestic poultry, and are capable of causing sporadic bird-to-human transmissions. AIVs capable of infecting humans include a highly pathogenic AIV H5N1, first detected in humans in 1997, and a low pathogenic AIV H7N9, reported in humans in 2013. Both H5N1 and H7N9 cause severe influenza disease in humans, manifested by acute respiratory distress syndrome, multi-organ failure, and high mortality rates of 60% and 35%, respectively. Ongoing circulation of H5N1 and H7N9 viruses in wild birds and poultry, and their ability to infect humans emphasizes their epidemic and pandemic potential and poses a public health threat. It is, thus, imperative to understand the host immune responses to the AIVs so we can control severe influenza disease caused by H5N1 or H7N9 and rationally design new immunotherapies and vaccines. This review summarizes our current knowledge on AIV epidemiology, disease symptoms, inflammatory processes underlying the AIV infection in humans, and recent studies on universal pre-existing CD8+ T cell immunity to AIVs. Immune responses driving the host recovery from AIV infection in patients hospitalized with severe influenza disease are also discussed. PMID:26973644

  10. CD8+ T cells cause disability and axon loss in a mouse model of multiple sclerosis.

    Directory of Open Access Journals (Sweden)

    Chandra Deb

    Full Text Available BACKGROUND: The objective of this study was to test the hypothesis that CD8+ T cells directly mediate motor disability and axon injury in the demyelinated central nervous system. We have previously observed that genetic deletion of the CD8+ T cell effector molecule perforin leads to preservation of motor function and preservation of spinal axons in chronically demyelinated mice. METHODOLOGY/PRINCIPAL FINDINGS: To determine if CD8+ T cells are necessary and sufficient to directly injure demyelinated axons, we adoptively transferred purified perforin-competent CD8+ spinal cord-infiltrating T cells into profoundly demyelinated but functionally preserved perforin-deficient host mice. Transfer of CD8+ spinal cord-infiltrating T cells rapidly and irreversibly impaired motor function, disrupted spinal cord motor conduction, and reduced the number of medium- and large-caliber spinal axons. Likewise, immunodepletion of CD8+ T cells from chronically demyelinated wildtype mice preserved motor function and limited axon loss without altering other disease parameters. CONCLUSIONS/SIGNIFICANCE: In multiple sclerosis patients, CD8+ T cells outnumber CD4+ T cells in active lesions and the number of CD8+ T cells correlates with the extent of ongoing axon injury and functional disability. Our findings suggest that CD8+ T cells may directly injure demyelinated axons and are therefore a viable therapeutic target to protect axons and motor function in patients with multiple sclerosis.

  11. Efficacious early antiviral activity of HIV Gag- and Pol-specific HLA-B 2705-restricted CD8+ T cells

    DEFF Research Database (Denmark)

    Payne, Rebecca P; Kløverpris, Henrik; Sacha, Jonah B;

    2010-01-01

    The association between HLA-B 2705 and the immune control of human immunodeficiency virus type 1 (HIV-1) has previously been linked to the targeting of the HLA-B 2705-restricted Gag epitope KRWIILGLNK (KK10) by CD8(+) T cells. In order to better define the mechanisms of the HLA-B 2705 immune...... control of HIV, we first characterized the CD8(+) T-cell responses of nine highly active antiretroviral therapy (HAART)-naïve B 2705-positive subjects. Unexpectedly, we observed a strong response to an HLA-B 2705-restricted Pol epitope, KRKGGIGGY (KY9), in 8/9 subjects. The magnitude of the KY9 response...... recognition of HIV-1-infected cells, within 6 h of infection, by KK10- and KY9-specific CD8(+) T cells but not until 18 h postinfection by VL9-specific CD8(+) T cells. There was no association between antiviral efficacy and proliferative capacity, cytotoxicity, polyfunctionality, or T-cell receptor (TCR...

  12. Large scale analysis of pediatric antiviral CD8+ T cell populations reveals sustained, functional and mature responses

    Directory of Open Access Journals (Sweden)

    Northfield John

    2006-12-01

    Full Text Available Abstract Background Cellular immunity plays a crucial role in cytomegalovirus (CMV infection and substantial populations of CMV-specific T cells accumulate throughout life. However, although CMV infection occurs during childhood, relatively little is know about the typical quantity and quality of T cell responses in pediatric populations. Methods One thousand and thirty-six people (Male/Female = 594/442, Age: 0–19 yr.; 959 subjects, 20–29 yr.; 77 subjects were examined for HLA typing. All of 1036 subjects were tested for HLA-A2 antigen. Of 1036 subjects, 887 were also tested for HLA-A23, 24 antigens. In addition, 50 elderly people (Male/Female = 11/39, Age: 60–92 yr. were also tested for HLA-A2 antigen. We analyzed the CD8+ T cell responses to CMV, comparing these to responses in children and young. The frequencies, phenotype and function CD8+ T cells for two imunodominant epitopes from pp65 were measured. Results We observed consistently high frequency and phenotypically "mature" (CD27 low, CD28 low, CD45RA+ CMV-specific CD8+ T cell responses in children, including those studied in the first year of life. These CD8+ T cells retained functionality across all age groups, and showed evidence of memory "inflation" only in later adult life. Conclusion CMV consistently elicits a very strong CD8+ T cell response in infants and large pools of CMV specific CD8+ T cells are maintained throughout childhood. The presence of CMV may considerably mould the CD8+ T cell compartment over time, but the relative frequencies of CMV-specific cells do not show the evidence of a population-level increase during childhood and adulthood. This contrast with the marked expansion ("inflation" of such CD8+ T cells in older adults. This study indicates that large scale analysis of peptide specific T cell responses in infants is readily possible. The robust nature of the responses observed suggests vaccine strategies aimed at priming and boosting CD8+ T cells against

  13. Sustained CD8+ T-cell responses induced after acute parvovirus B19 infection in humans

    DEFF Research Database (Denmark)

    Norbeck, Oscar; Isa, Adiba; Pöhlmann, Christoph;

    2005-01-01

    Murine models have suggested that CD8+ T-cell responses peak early in acute viral infections and are not sustained, but no evidence for humans has been available. To address this, we longitudinally analyzed the CD8+ T-cell response to human parvovirus B19 in acutely infected individuals. We...... observed striking CD8+ T-cell responses, which were sustained or even increased over many months after the resolution of acute disease, indicating that CD8+ T cells may play a prominent role in the control of parvovirus B19 and other acute viral infections of humans, including potentially those generated...

  14. Mast-Cell-Derived TNF Amplifies CD8+ Dendritic Cell Functionality and CD8+ T Cell Priming

    Directory of Open Access Journals (Sweden)

    Jan Dudeck

    2015-10-01

    Full Text Available Mast cells are critical promoters of adaptive immunity in the contact hypersensitivity model, but the mechanism of allergen sensitization is poorly understood. Using Mcpt5-CreTNFFL/FL mice, we show here that the absence of TNF exclusively in mast cells impaired the expansion of CD8+ T cells upon sensitization and the T-cell-driven adaptive immune response to elicitation. T cells primed in the absence of mast cell TNF exhibited a diminished efficiency to transfer sensitization to naive recipients. Specifically, mast cell TNF promotes CD8+ dendritic cell (DC maturation and migration to draining lymph nodes. The peripherally released mast cell TNF further critically boosts the CD8+ T-cell-priming efficiency of CD8+ DCs, thereby linking mast cell effects on T cells to DC modulation. Collectively, our findings identify the distinct potential of mast cell TNF to amplify CD8+ DC functionality and CD8+ T-cell-dominated adaptive immunity, which may be of great importance for immunotherapy and vaccination approaches.

  15. Immediate dysfunction of vaccine-elicited CD8+ T cells primed in the absence of CD4+ T cells

    Science.gov (United States)

    Provine, Nicholas M.; Larocca, Rafael A.; Aid, Malika; Penaloza-MacMaster, Pablo; Badamchi-Zadeh, Alexander; Borducchi, Erica N.; Yates, Kathleen B.; Abbink, Peter; Kirilova, Marinela; Ng’ang’a, David; Bramson, Jonathan; Haining, W. Nicholas; Barouch, Dan H.

    2016-01-01

    CD4+ T cell help is critical for optimal CD8+ T cell memory differentiation and maintenance in many experimental systems. Additionally, many reports have identified reduced primary CD8+ T cell responses in the absence of CD4+ T cell help, which often coincides with reduced antigen or pathogen clearance. Here we demonstrate that absence of CD4+ T cells at the time of adenovirus vector immunization of mice led to immediate impairments in early CD8+ T cell functionality and differentiation. Unhelped CD8+ T cells exhibited a reduced effector phenotype, decreased ex vivo cytotoxicity, and decreased capacity to produce cytokines. This dysfunctional state was imprinted within 3 days of immunization. Unhelped CD8+ T cells expressed elevated levels of inhibitory receptors and exhibited transcriptomic exhaustion and anergy profiles by gene set enrichment analysis. Dysfunctional, impaired effector differentiation also occurred following immunization of CD4+ T cell-deficient mice with a poxvirus vector. This study demonstrates that following priming with viral vectors, CD4+ T cell help is required to promote both the expansion and acquisition of effector functions by CD8+ T cells, which is accomplished by preventing immediate dysfunction. PMID:27448585

  16. HDAC1 controls CD8+ T cell homeostasis and antiviral response.

    Directory of Open Access Journals (Sweden)

    Roland Tschismarov

    Full Text Available Reversible lysine acetylation plays an important role in the regulation of T cell responses. HDAC1 has been shown to control peripheral T helper cells, however the role of HDAC1 in CD8+ T cell function remains elusive. By using conditional gene targeting approaches, we show that LckCre-mediated deletion of HDAC1 led to reduced numbers of thymocytes as well as peripheral T cells, and to an increased fraction of CD8+CD4- cells within the CD3/TCRβlo population, indicating that HDAC1 is essential for the efficient progression of immature CD8+CD4- cells to the DP stage. Moreover, CD44hi effector CD8+ T cells were enhanced in mice with a T cell-specific deletion of HDAC1 under homeostatic conditions and HDAC1-deficient CD44hi CD8+ T cells produced more IFNγ upon ex vivo PMA/ionomycin stimulation in comparison to wild-type cells. Naïve (CD44l°CD62L+ HDAC1-null CD8+ T cells displayed a normal proliferative response, produced similar amounts of IL-2 and TNFα, slightly enhanced amounts of IFNγ, and their in vivo cytotoxicity was normal in the absence of HDAC1. However, T cell-specific loss of HDAC1 led to a reduced anti-viral CD8+ T cell response upon LCMV infection and impaired expansion of virus-specific CD8+ T cells. Taken together, our data indicate that HDAC1 is required for the efficient generation of thymocytes and peripheral T cells, for proper CD8+ T cell homeostasis and for an efficient in vivo expansion and activation of CD8+ T cells in response to LCMV infection.

  17. Stepwise identification of HLA-A*0201-restricted CD8+ T-cell epitope peptides from herpes simplex virus type 1 genome boosted by a StepRank scheme.

    Science.gov (United States)

    Bi, Jianjun; Song, Rengang; Yang, Huilan; Li, Bingling; Fan, Jianyong; Liu, Zhongrong; Long, Chaoqin

    2011-01-01

    Identification of immunodominant epitopes is the first step in the rational design of peptide vaccines aimed at T-cell immunity. To date, however, it is yet a great challenge for accurately predicting the potent epitope peptides from a pool of large-scale candidates with an efficient manner. In this study, a method that we named StepRank has been developed for the reliable and rapid prediction of binding capabilities/affinities between proteins and genome-wide peptides. In this procedure, instead of single strategy used in most traditional epitope identification algorithms, four steps with different purposes and thus different computational demands are employed in turn to screen the large-scale peptide candidates that are normally generated from, for example, pathogenic genome. The steps 1 and 2 aim at qualitative exclusion of typical nonbinders by using empirical rule and linear statistical approach, while the steps 3 and 4 focus on quantitative examination and prediction of the interaction energy profile and binding affinity of peptide to target protein via quantitative structure-activity relationship (QSAR) and structure-based free energy analysis. We exemplify this method through its application to binding predictions of the peptide segments derived from the 76 known open-reading frames (ORFs) of herpes simplex virus type 1 (HSV-1) genome with or without affinity to human major histocompatibility complex class I (MHC I) molecule HLA-A*0201, and find that the predictive results are well compatible with the classical anchor residue theory and perfectly match for the extended motif pattern of MHC I-binding peptides. The putative epitopes are further confirmed by comparisons with 11 experimentally measured HLA-A*0201-restrcited peptides from the HSV-1 glycoproteins D and K. We expect that this well-designed scheme can be applied in the computational screening of other viral genomes as well. PMID:21072852

  18. Characterization of CD8+ T cell differentiation following SIVΔnef vaccination by transcription factor expression profiling.

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    James M Billingsley

    2015-03-01

    Full Text Available The onset of protective immunity against pathogenic SIV challenge in SIVΔnef-vaccinated macaques is delayed for 15-20 weeks, a process that is related to qualitative changes in CD8+ T cell responses induced by SIVΔnef. As a novel approach to characterize cell differentiation following vaccination, we used multi-target qPCR to measure transcription factor expression in naïve and memory subsets of CD8++ T cells, and in SIV-specific CD8+ T cells obtained from SIVΔnef-vaccinated or wild type SIVmac239-infected macaques. Unsupervised clustering of expression profiles organized naïve and memory CD8+ T cells into groups concordant with cell surface phenotype. Transcription factor expression patterns in SIV-specific CD8+ T cells in SIVΔnef-vaccinated animals were distinct from those observed in purified CD8+ T cell subsets obtained from naïve animals, and were intermediate to expression profiles of purified central memory and effector memory T cells. Expression of transcription factors elicited by SIVΔnef vaccination also varied over time: cells obtained at later time points, temporally associated with greater protection, appeared more central-memory like than cells obtained at earlier time points, which appeared more effector memory-like. Expression of transcription factors associated with effector differentiation, such as ID2 and RUNX3, were decreased over time, while expression of transcription factors associated with quiescence or memory differentiation, such as TCF7, BCOR and EOMES, increased. CD8+ T cells specific for a more conserved epitope expressed higher levels of TBX21 and BATF, and appeared more effector-like than cells specific for an escaped epitope, consistent with continued activation by replicating vaccine virus. These data suggest transcription factor expression profiling is a novel method that can provide additional data complementary to the analysis of memory cell differentiation based on classical phenotypic markers

  19. Why Do CD8+ T Cells become Indifferent to Tumors: A Dynamic Modeling Approach.

    Science.gov (United States)

    Campbell, Colin; Zhang, Ranran; Haley, Jeremy S; Liu, Xin; Loughran, Thomas; Schell, Todd D; Albert, Réka; Thakar, Juilee

    2011-01-01

    CD8+ T cells have the potential to influence the outcome of cancer pathogenesis, including complete tumor eradication or selection of malignant tumor escape variants. The Simian virus 40 large T-antigen (Tag) oncoprotein promotes tumor formation in Tag-transgenic mice and also provides multiple target determinants (sites) for responding CD8+ T cells in C57BL/6 (H-2(b)) mice. To understand the in vivo quantitative dynamics of CD8+ T cells after encountering Tag, we constructed a dynamic model from in vivo-generated data to simulate the interactions between Tag-expressing cells and CD8+ T cells in distinct scenarios including immunization of wild-type C57BL/6 mice and of Tag-transgenic mice that develop various tumors. In these scenarios the model successfully reproduces the dynamics of both the Tag-expressing cells and antigen-specific CD8+ T cell responses. The model predicts that the tolerance of the site-specific T cells is dependent on their apoptosis rates and that the net growth of CD8+ T cells is altered in transgenic mice. We experimentally validate both predictions. Our results indicate that site-specific CD8+ T cells have tissue-specific apoptosis rates affecting their tolerance to the tumor antigen. Moreover, the model highlights differences in apoptosis rates that contribute to compromised CD8+ T cell responses and tumor progression, knowledge of which is essential for development of cancer immunotherapy. PMID:21808621

  20. Heterogeneity in the differentiation and function of CD8T cells.

    Science.gov (United States)

    Mittrücker, Hans-Willi; Visekruna, Alexander; Huber, Magdalena

    2014-12-01

    It is well established that CD8(+) T cells constitute an important branch of adaptive immunity contributing to clearance of intracellular pathogens and providing long-term protection. These functions are mostly fulfilled by the best characterized subpopulation of CD8(+) T cells, the cytotoxic T lymphocytes (also called Tc1 cells), owing to their ability to kill infected cells and to secrete cytokines such as interferon-γ and tumor necrosis factor-α. However, there is growing evidence for alternative CD8(+) T cell fates influencing CD4(+) T-cell-mediated responses in the context of allergy, autoimmunity and infections. Thus, like subpopulations of CD4(+) T cells, also CD8(+) T cells under particular conditions acquire the expression of interleukin (IL)-4, IL-5, IL-9, IL-13, IL-17 or suppressive activity and thereby influence immune responses. The process of CD8(+) T-cell differentiation is dictated by antigen strength, co-stimulatory molecules and cytokines. These environmental cues induce transcription factors further specifying CD8(+) T-cell decision into Tc1, Tc2, Tc9, Tc17 or CD8(+) T regulatory fate. Here, we discuss our current understanding about functional diversity of effector CD8(+) T cells and contribution of transcription factors to this process. PMID:24879097

  1. Why Do CD8 + T Cells Become Indifferent To Tumors: A Dynamic Modeling Approach

    Directory of Open Access Journals (Sweden)

    Colin eCampbell

    2011-07-01

    Full Text Available CD8+ T cells have the potential to influence the outcome of cancer pathogenesis, including complete tumor eradication or selection of malignant tumor escape variants. The Simian virus 40 large T-antigen oncoprotein promotes tumor formation in T-antigen transgenic mice and also provides multiple target determinants (sites for responding CD8+ T cells in C57BL/6 (H-2b mice. To understand the in vivo quantitative dynamics of CD8+ T cells after encountering T-antigen, we constructed a dynamic model from in vivo-generated data to simulate the interactions between T-antigen expressing cells and CD8+ T cells in distinct scenarios including immunization of wild type C57BL/6 mice and of T-antigen transgenic mice that develop various tumors. In these scenarios the model successfully reproduces the dynamics of both the T-antigen-expressing cells and antigen specific CD8+ T cell responses. The model predicts that the tolerance of the site-specific T cells is dependent on their apoptosis rates and that the net growth of CD8+ T cells is altered in transgenic mice. We experimentally validate both predictions. Our results indicate that site-specific CD8+ T cells have tissue-specific apoptosis rates affecting their tolerance to the tumor antigen. Moreover, the model highlights differences in apoptosis rates that contribute to compromised CD8+ T cell responses and tumor progression, knowledge of which is essential for development of cancer immunotherapy.

  2. Prediction of CD8+ Epitopes in Leishmania braziliensis Proteins Using EPIBOT: In Silico Search and In Vivo Validation.

    Directory of Open Access Journals (Sweden)

    Angelo Duarte

    Full Text Available Leishmaniasis is caused by intracellular Leishmania parasites that induce a T-cell mediated response associated with recognition of CD4+ and CD8+ T cell Line 1Lineepitopes. Identification of CD8+ antigenic determinants is crucial for vaccine and therapy development. Herein, we developed an open-source software dedicated to search and compile data obtained from currently available on line prediction algorithms.We developed a two-phase algorithm and implemented in an open source software called EPIBOT, that consolidates the results obtained with single prediction algorithms, generating a final output in which epitopes are ranked. EPIBOT was initially trained using a set of 831 known epitopes from 397 proteins from IEDB. We then screened 63 Leishmania braziliensis vaccine candidates with the EPIBOT trained tool to search for CD8+ T cell epitopes. A proof-of-concept experiment was conducted with the top eight CD8+ epitopes, elected by EPIBOT. To do this, the elected peptides were synthesized and validated for their in vivo cytotoxicity. Among the tested epitopes, three were able to induce lysis of pulsed-target cells.Our results show that EPIBOT can successfully search across existing prediction tools, generating a compiled list of candidate CD8+ epitopes. This software is fast and a simple search engine that can be customized to search over different MHC alleles or HLA haplotypes.

  3. Inhibiting glycolytic metabolism enhances CD8+ T cell memory and antitumor function

    OpenAIRE

    Sukumar, Madhusudhanan; Liu, Jie; Ji, Yun; Subramanian, Murugan; Crompton, Joseph G.; Yu, Zhiya; Roychoudhuri, Rahul; Palmer, Douglas C.; Muranski, Pawel; Karoly, Edward D; Mohney, Robert P.; Klebanoff, Christopher A.; Lal, Ashish; Finkel, Toren; Restifo, Nicholas P.

    2013-01-01

    Naive CD8+ T cells rely upon oxidation of fatty acids as a primary source of energy. After antigen encounter, T cells shift to a glycolytic metabolism to sustain effector function. It is unclear, however, whether changes in glucose metabolism ultimately influence the ability of activated T cells to become long-lived memory cells. We used a fluorescent glucose analog, 2-NBDG, to quantify glucose uptake in activated CD8+ T cells. We found that cells exhibiting limited glucose incorporation had ...

  4. Generation and Regulation of CD8+ Regulatory T Cells

    Institute of Scientific and Technical Information of China (English)

    Linrong Lu; Harvey Cantor

    2008-01-01

    Research into the suppressive activity of CD4+FoxP3+ T regulatory cells (Treg) has defined a sublineage of CD4+ cells that contribute to self-tolerance and resistance to autoimmune disease. Much less attention has been given to the potential contribution of regulatory sublineages of CD8+ cells. Analysis of a small fraction of CD8+ cells that target autoreactive CD4+ cells through recognition of the MHC class Ib molecule Qa-1 in mouse and HLA-E in human has revitalized interest in CD8+ Treg. Here we summarize recent progress and future directions of research into the role of this CD8+ sublineage in resistance to autoimmune disease. Cellular & Molecular Immunology. 2008;5(6):401-406.

  5. Change of paradigm: CD8+ T cells as important helper for CD4+ T cells during asthma and autoimmune encephalomyelitis

    OpenAIRE

    Huber, Magdalena; Lohoff, Michael

    2015-01-01

    Summary The activation of naive CD4+ and CD8+ T cells in response to antigen and their subsequent proliferation and differentiation into effectors are important features of a cell-mediated immune response. CD4+ T cells (also known as T helper cells, Th) differentiate into several subpopulations including Th1, Th2, Th9, Th17, Tfh and Treg cells, characterized by specific cytokine profiles and effector functions. However, recent evidence indicates that CD8+ T cells (termed cytotoxic T lymphocyt...

  6. Contribution of Herpesvirus Specific CD8 T Cells to Anti-Viral T Cell Response in Humans

    OpenAIRE

    Elena Sandalova; Diletta Laccabue; Carolina Boni; Tan, Anthony T.; Katja Fink; Eng Eong Ooi; Robert Chua; Bahar Shafaeddin Schreve; Carlo Ferrari; Antonio Bertoletti

    2010-01-01

    Herpesviruses infect most humans. Their infections can be associated with pathological conditions and significant changes in T cell repertoire but evidences of symbiotic effects of herpesvirus latency have never been demonstrated. We tested the hypothesis that HCMV and EBV-specific CD8 T cells contribute to the heterologous anti-viral immune response. Volume of activated/proliferating virus-specific and total CD8 T cells was evaluated in 50 patients with acute viral infections: 20 with HBV, 1...

  7. Distribution, characterization, and induction of CD8+ regulatory T cells and IL-17-producing CD8+ T cells in nasopharyngeal carcinoma

    Directory of Open Access Journals (Sweden)

    Li Jiang

    2011-11-01

    Full Text Available Abstract Background CD8+ effector cells often have an antitumor function in patients with cancer. However, CD8+Foxp3+ regulatory T cells (Tcregs and interleukin (IL-17-producing CD8+ T cells (Tc17 cells also derive from the CD8+ T cell lineage. Their role in the antitumor response remains largely unknown. In the present study, we aimed to investigate the distribution, characterization, and generation of CD8+ Tcregs and Tc17 cells in NPC patients. Methods Peripheral blood and tumor biopsy tissues from 21 newly diagnosed patients with nasopharyngeal carcinoma (NPC were collected, along with peripheral blood from 21 healthy donors. The biological characteristics of Tcregs and Tc17 cells from blood and tumor tissues were examined by intracellular staining, tetramer staining and fluorescence-activated cell sorting (FACS analysis. The suppressive function of Tcregs was investigated using a proliferation assay that involved co-culture of sorted CD8+CD25+ T cells with naïve CD4+ T cells in vitro. Results We observed an increased prevalence of Tcregs and Tc17 cells among tumor-infiltrating lymphocytes (TILs and different distribution among peripheral blood mononuclear cells (PBMCs in NPC patients. Cytokine profiles showed that the Tcregs expressed a high level of IL-10 and low level of transforming growth factor β, whereas Tc17 cells expressed a high level of tumor necrosis factor α. Interestingly, both subsets expressed a high level of interferon γ in TILs, and the Tcregs suppressed naïve CD4+ T cell proliferation by a cell contact-dependent mechanism in vitro. Moreover, we demonstrated the existence of Epstein-Barr virus latent membrane protein (LMP 1 and LMP2 antigen-specific Tcregs in NPC. Conclusions Our data provide new insights into the composition and function of CD8+ T-cell subsets in NPC, which may have an important influence on NPC immunotherapy.

  8. Identification and HLA-Tetramer-Validation of Human CD4(+) and CD8(+) T Cell Responses against HCMV Proteins IE1 and IE2

    DEFF Research Database (Denmark)

    Braendstrup, Peter; Mortensen, Bo Kok; Justesen, Sune Frederik Lamdahl;

    2014-01-01

    tumor development. Both CD4(+) and CD8(+) T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8(+) T cell......-typed, donors were screened by ex vivo IFN-gamma ELISpot and in vitro intracellular cytokine secretion assays. The specificities of CD4(+) and CD8(+) T cell responses were identified and validated by HLA class II and I tetramers, respectively. Eighty-one CD4(+) and 44 CD8(+) T cell responses were identified...... in IE1 and IE2 were recognized in about half of the analyzed donors. These data may be used to design a versatile anti-HCMV vaccine and/or immunotherapy strategy....

  9. A Pathogenic Role for CD8+ T Cells in a Spontaneous Model of Demyelinating Disease

    DEFF Research Database (Denmark)

    Brisebois, Marcel; Zehntner, Simone P.; Estrada, José;

    2006-01-01

    Transgenic (Tg) mice that overexpress the costimulatory ligand B7.2/CD86 on microglia spontaneously develop a T cell-mediated demyelinating disease. Characterization of the inflammatory infiltrates in the nervous tissue revealed a predominance of CD8+ T cells, suggesting a prominent role of this T...... pathogenesis. Collectively, our data indicate that the spontaneous demyelinating disease in this animal model occurs as a consequence of an inflammatory response initiated through the activation of CNS-specific CD8+ T cells by Tg expression of B7.2 within the target organ. Thus, autoreactive CD8+ T cells can...

  10. DOCK8 deficiency impairs CD8 T cell survival and function in humans and mice

    Science.gov (United States)

    Randall, Katrina L.; Chan, Stephanie S.-Y.; Ma, Cindy S.; Fung, Ivan; Mei, Yan; Yabas, Mehmet; Tan, Andy; Arkwright, Peter D.; Al Suwairi, Wafaa; Lugo Reyes, Saul Oswaldo; Yamazaki-Nakashimada, Marco A.; de la Luz Garcia-Cruz, Maria; Smart, Joanne M.; Picard, Capucine; Okada, Satoshi; Jouanguy, Emmanuelle; Casanova, Jean-Laurent; Lambe, Teresa; Cornall, Richard J.; Russell, Sarah; Oliaro, Jane; Tangye, Stuart G.; Bertram, Edward M.

    2011-01-01

    In humans, DOCK8 immunodeficiency syndrome is characterized by severe cutaneous viral infections. Thus, CD8 T cell function may be compromised in the absence of DOCK8. In this study, by analyzing mutant mice and humans, we demonstrate a critical, intrinsic role for DOCK8 in peripheral CD8 T cell survival and function. DOCK8 mutation selectively diminished the abundance of circulating naive CD8 T cells in both species, and in DOCK8-deficient humans, most CD8 T cells displayed an exhausted CD45RA+CCR7− phenotype. Analyses in mice revealed the CD8 T cell abnormalities to be cell autonomous and primarily postthymic. DOCK8 mutant naive CD8 T cells had a shorter lifespan and, upon encounter with antigen on dendritic cells, exhibited poor LFA-1 synaptic polarization and a delay in the first cell division. Although DOCK8 mutant T cells underwent near-normal primary clonal expansion after primary infection with recombinant influenza virus in vivo, they showed greatly reduced memory cell persistence and recall. These findings highlight a key role for DOCK8 in the survival and function of human and mouse CD8 T cells. PMID:22006977

  11. Cish actively silences TCR signaling in CD8+ T cells to maintain tumor tolerance

    OpenAIRE

    Douglas C Palmer; Guittard, Geoffrey C.; Franco, Zulmarie; Crompton, Joseph G.; Eil, Robert L; Patel, Shashank J.; Ji, Yun; van Panhuys, Nicholas; Klebanoff, Christopher A.; Sukumar, Madhusudhanan; Clever, David; Chichura, Anna; Roychoudhuri, Rahul; Varma, Rajat; Wang, Ena

    2015-01-01

    Improving the functional avidity of effector T cells is critical in overcoming inhibitory factors within the tumor microenvironment and eliciting tumor regression. We have found that Cish, a member of the suppressor of cytokine signaling (SOCS) family, is induced by TCR stimulation in CD8+ T cells and inhibits their functional avidity against tumors. Genetic deletion of Cish in CD8+ T cells enhances their expansion, functional avidity, and cytokine polyfunctionality, resulting in pronounced a...

  12. CD8+ T cells induce platelet clearance in the liver via platelet desialylation in immune thrombocytopenia

    Science.gov (United States)

    Qiu, Jihua; Liu, Xuena; Li, Xiaoqing; Zhang, Xu; Han, Panpan; Zhou, Hai; Shao, Linlin; Hou, Yu; Min, Yanan; Kong, Zhangyuan; Wang, Yawen; Wei, Yu; Liu, Xinguang; Ni, Heyu; Peng, Jun; Hou, Ming

    2016-01-01

    In addition to antiplatelet autoantibodies, CD8+ cytotoxic T lymphocytes (CTLs) play an important role in the increased platelet destruction in immune thrombocytopenia (ITP). Recent studies have highlighted that platelet desialylation leads to platelet clearance via hepatocyte asialoglycoprotein receptors (ASGPRs). Whether CD8+ T cells induce platelet desialylation in ITP remains unclear. Here, we investigated the cytotoxicity of CD8+ T cells towards platelets and platelet desialylation in ITP. We found that the desialylation of fresh platelets was significantly higher in ITP patients with positive cytotoxicity of CD8+ T cells than those without cytotoxicity and controls. In vitro, CD8+ T cells from ITP patients with positive cytotoxicity induced significant platelet desialylation, neuraminidase-1 expression on the platelet surface, and platelet phagocytosis by hepatocytes. To study platelet survival and clearance in vivo, CD61 knockout mice were immunized and their CD8+ splenocytes were used. Platelets co-cultured with these CD8+ splenocytes demonstrated decreased survival in the circulation and increased phagocytosis in the liver. Both neuraminidase inhibitor and ASGPRs competitor significantly improved platelet survival and abrogated platelet clearance caused by CD8+ splenocytes. These findings suggest that CD8+ T cells induce platelet desialylation and platelet clearance in the liver in ITP, which may be a novel mechanism of ITP. PMID:27321376

  13. CD8(+) T cells induce platelet clearance in the liver via platelet desialylation in immune thrombocytopenia.

    Science.gov (United States)

    Qiu, Jihua; Liu, Xuena; Li, Xiaoqing; Zhang, Xu; Han, Panpan; Zhou, Hai; Shao, Linlin; Hou, Yu; Min, Yanan; Kong, Zhangyuan; Wang, Yawen; Wei, Yu; Liu, Xinguang; Ni, Heyu; Peng, Jun; Hou, Ming

    2016-01-01

    In addition to antiplatelet autoantibodies, CD8(+) cytotoxic T lymphocytes (CTLs) play an important role in the increased platelet destruction in immune thrombocytopenia (ITP). Recent studies have highlighted that platelet desialylation leads to platelet clearance via hepatocyte asialoglycoprotein receptors (ASGPRs). Whether CD8(+) T cells induce platelet desialylation in ITP remains unclear. Here, we investigated the cytotoxicity of CD8(+) T cells towards platelets and platelet desialylation in ITP. We found that the desialylation of fresh platelets was significantly higher in ITP patients with positive cytotoxicity of CD8(+) T cells than those without cytotoxicity and controls. In vitro, CD8(+) T cells from ITP patients with positive cytotoxicity induced significant platelet desialylation, neuraminidase-1 expression on the platelet surface, and platelet phagocytosis by hepatocytes. To study platelet survival and clearance in vivo, CD61 knockout mice were immunized and their CD8(+) splenocytes were used. Platelets co-cultured with these CD8(+) splenocytes demonstrated decreased survival in the circulation and increased phagocytosis in the liver. Both neuraminidase inhibitor and ASGPRs competitor significantly improved platelet survival and abrogated platelet clearance caused by CD8(+) splenocytes. These findings suggest that CD8(+) T cells induce platelet desialylation and platelet clearance in the liver in ITP, which may be a novel mechanism of ITP. PMID:27321376

  14. Neonatal CD8+ T-cell differentiation is dependent on interleukin-12.

    LENUS (Irish Health Repository)

    McCarron, Mark J

    2012-02-01

    Neonatal CD8(+) T-cell activation is significantly impaired compared with that in adults. Recent studies have demonstrated that interleukin (IL)-12 is necessary as a third signal, in addition to antigen and co-stimulation, to authorize the differentiation of naive CD8(+) T cells. We examined whether human neonatal CD8(+) T cells, which possess an exclusively naive T-cell phenotype, required a third signal to authorize a productive T-cell response. IL-12 enhanced activated naive CD8(+) T-cell survival, expansion, CD25 expression, and IL-2 production. Activated CD8(+) T cells produced interferon-gamma and intracellular granzyme B and were cytotoxic only in the presence of IL-12. Sustained IL-12 signaling for 72 hours was required for optimal interferon-gamma production. IL-12, in concert with T cell receptor (TCR) stimulation, sustained late-stage (48-72 hours) intracellular phosphorylation and particularly total protein levels of the proximal TCR components, Lck, and CD3xi. The requirement for a third signal for productive human neonatal CD8(+) T-cell differentiation may have implications for neonatal vaccination strategies.

  15. Blimp-1-mediated CD4 T cell exhaustion causes CD8 T cell dysfunction during chronic toxoplasmosis.

    Science.gov (United States)

    Hwang, SuJin; Cobb, Dustin A; Bhadra, Rajarshi; Youngblood, Ben; Khan, Imtiaz A

    2016-08-22

    CD8, but not CD4, T cells are considered critical for control of chronic toxoplasmosis. Although CD8 exhaustion has been previously reported in Toxoplasma encephalitis (TE)-susceptible model, our current work demonstrates that CD4 not only become exhausted during chronic toxoplasmosis but this dysfunction is more pronounced than CD8 T cells. Exhausted CD4 population expressed elevated levels of multiple inhibitory receptors concomitant with the reduced functionality and up-regulation of Blimp-1, a transcription factor. Our data demonstrates for the first time that Blimp-1 is a critical regulator for CD4 T cell exhaustion especially in the CD4 central memory cell subset. Using a tamoxifen-dependent conditional Blimp-1 knockout mixed bone marrow chimera as well as an adoptive transfer approach, we show that CD4 T cell-intrinsic deletion of Blimp-1 reversed CD8 T cell dysfunction and resulted in improved pathogen control. To the best of our knowledge, this is a novel finding, which demonstrates the role of Blimp-1 as a critical regulator of CD4 dysfunction and links it to the CD8 T cell dysfunctionality observed in infected mice. The critical role of CD4-intrinsic Blimp-1 expression in mediating CD4 and CD8 T cell exhaustion may provide a rational basis for designing novel therapeutic approaches. PMID:27481131

  16. T cell metabolism. The protein LEM promotes CD8T cell immunity through effects on mitochondrial respiration.

    Science.gov (United States)

    Okoye, Isobel; Wang, Lihui; Pallmer, Katharina; Richter, Kirsten; Ichimura, Takahuru; Haas, Robert; Crouse, Josh; Choi, Onjee; Heathcote, Dean; Lovo, Elena; Mauro, Claudio; Abdi, Reza; Oxenius, Annette; Rutschmann, Sophie; Ashton-Rickardt, Philip G

    2015-05-29

    Protective CD8(+) T cell-mediated immunity requires a massive expansion in cell number and the development of long-lived memory cells. Using forward genetics in mice, we identified an orphan protein named lymphocyte expansion molecule (LEM) that promoted antigen-dependent CD8(+) T cell proliferation, effector function, and memory cell generation in response to infection with lymphocytic choriomeningitis virus. Generation of LEM-deficient mice confirmed these results. Through interaction with CR6 interacting factor (CRIF1), LEM controlled the levels of oxidative phosphorylation (OXPHOS) complexes and respiration, resulting in the production of pro-proliferative mitochondrial reactive oxygen species (mROS). LEM provides a link between immune activation and the expansion of protective CD8(+) T cells driven by OXPHOS and represents a pathway for the restoration of long-term protective immunity based on metabolically modified cytotoxic CD8(+) T cells.

  17. Accumulation of cytolytic CD8{sup +} T cells in B16-melanoma and proliferation of mature T cells in TIS21-knockout mice after T cell receptor stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Min Sook [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Woo, Min-Yeong [Department of Microbiology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Department of Biomedical Sciences, The Graduate School, Ajou University (Korea, Republic of); Kwon, Daeho [Department of Microbiology, Kwandong University College of Medicine, Gangneung, Gangwon-do 210-701 (Korea, Republic of); Hong, Allen E. [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Song, Kye Yong [Department of Pathology, Chung-Ang University College of Medicine, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Park, Sun [Department of Microbiology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of); Lim, In Kyoung [Department of Biochemistry and Molecular Biology, Ajou University School of Medicine, 164, World cul-ro, Yeongtong-gu, Suwon, Gyeonggi-do 443-380 (Korea, Republic of)

    2014-10-01

    In vivo and in vitro effects of TIS21 gene on the mature T cell activation and antitumor activities were explored by employing MO5 melanoma orthograft and splenocytes isolated from the TIS21-knockout (KO) mice. Proliferation and survival of mature T cells were significantly increased in the KO than the wild type (WT) cells, indicating that TIS21 inhibits the rate of mature T cell proliferation and its survival. In MO5 melanoma orthograft model, the KO mice recruited much more CD8{sup +} T cells into the tumors at around day 14 after tumor cell injection along with reduced tumor volumes compared with the WT. The increased frequency of granzyme B{sup +} CD8{sup +} T cells in splenocytes of the KO mice compared with the WT may account for antitumor-immunity of TIS21 gene in the melanoma orthograft. In contrast, reduced frequencies of CD107a{sup +} CD8{sup +} T cells in the splenocytes of KO mice may affect the loss of CD8{sup +} T cell infiltration in the orthograft at around day 19. These results indicate that TIS21 exhibits antiproliferative and proapoptotic effects in mature T cells, and differentially affects the frequencies of granzyme B{sup +} CD8{sup +} T-cells and CD107a{sup +} CD8{sup +} T-cells, thus transiently regulating in vivo anti-tumor immunity. - Highlights: • Constitutive expression of TIS21 in splenocytes and upregulation by TCR stimulation. • Proliferation of mature T-cells in spleen of TIS21KO mice after TCR stimulation. • Inhibition of cell death in mature T-cells of TIS21KO mice compared with the wild type. • Inhibition of melanoma growth in TIS21KO mice and CD8{sup +} T cell infiltration in tumor. • Reduction of CD 107{sup +}CD8{sup +} T cells, but increased granzyme B{sup +} CD8{sup +} T cells in TIS21KO mice.

  18. Tissue signatures influence the activation of intrahepatic CD8+ T cells against malaria sporozoites

    Directory of Open Access Journals (Sweden)

    Alexandre eMorrot

    2014-08-01

    Full Text Available Plasmodium sporozoites and liver stages express antigens that are targeted to the MHC-Class I antigen-processing pathway. After the introduction of Plasmodium sporozoites by Anopheles mosquitoes, bone marrow-derived dendritic cells in skin-draining lymph nodes are the first cells to cross-present parasite antigens and elicit specific CD8+ T cells. One of these antigens is the immunodominant circumsporozoite protein (CSP. The CD8+ T cell-mediated protective immune response against CSP is dependent on the interleukin loop involving IL-4 receptor expression on CD8+ cells and IL-4 secretion by CD4+ T cell helpers. In a few days, these CD8+ T cells re-circulate to secondary lymphoid organs and the liver. In the liver, the hepatic sinusoids are enriched with cells, such as dendritic, sinusoidal endothelial and Kupffer cells, that are able to cross-present MHC class I antigens to intrahepatic CD8+ T cells. Specific CD8+ T cells actively find infected hepatocytes and target intra-cellular parasites through mechanisms that are both Interferon-g-dependent and -independent. Immunity is mediated by CD8+ T effector or effector-memory cells and, when present in high numbers, these cells can provide sterilizing immunity. Human vaccination trials with recombinant formulations or attenuated sporozoites have yet to achieve the high numbers of specific effector T cells that are required for sterilizing immunity. In spite of the limited number of specific CD8+ T cells, attenuated sporozoites provided multiple times by the endovenous route provided a high degree of protective immunity. These observations highlight that CD8+ T cells may be useful for improving antibody-mediated protective immunity to pre-erythrocytic stages of malaria parasites.

  19. CD8+ T Cell Response to Gammaherpesvirus Infection Mediates Inflammation and Fibrosis in Interferon Gamma Receptor-Deficient Mice.

    Directory of Open Access Journals (Sweden)

    Brigid M O'Flaherty

    Full Text Available Idiopathic pulmonary fibrosis (IPF, one of the most severe interstitial lung diseases, is a progressive fibrotic disorder of unknown etiology. However, there is growing appreciation for the role of viral infection in disease induction and/or progression. A small animal model of multi-organ fibrosis, which involves murine gammaherpesvirus (MHV68 infection of interferon gamma receptor deficient (IFNγR-/- mice, has been utilized to model the association of gammaherpesvirus infections and lung fibrosis. Notably, several MHV68 mutants which fail to induce fibrosis have been identified. Our current study aimed to better define the role of the unique MHV68 gene, M1, in development of pulmonary fibrosis. We have previously shown that the M1 gene encodes a secreted protein which possesses superantigen-like function to drive the expansion and activation of Vβ4+ CD8+ T cells. Here we show that M1-dependent fibrosis is correlated with heightened levels of inflammation in the lung. We observe an M1-dependent cellular infiltrate of innate immune cells with most striking differences at 28 days-post infection. Furthermore, in the absence of M1 protein expression we observed reduced CD8+ T cells and MHV68 epitope specific CD8+ T cells to the lungs-despite equivalent levels of viral replication between M1 null and wild type MHV68. Notably, backcrossing the IFNγR-/- onto the Balb/c background, which has previously been shown to exhibit weak MHV68-driven Vβ4+ CD8+ T cell expansion, eliminated MHV68-induced fibrosis-further implicating the activated Vβ4+ CD8+ T cell population in the induction of fibrosis. We further addressed the role that CD8+ T cells play in the induction of fibrosis by depleting CD8+ T cells, which protected the mice from fibrotic disease. Taken together these findings are consistent with the hypothesized role of Vβ4+ CD8+ T cells as mediators of fibrotic disease in IFNγR-/- mice.

  20. CD8+ T Cells Complement Antibodies in Protecting against Yellow Fever Virus

    DEFF Research Database (Denmark)

    Bassi, Maria R; Kongsgaard, Michael; Steffensen, Maria A;

    2015-01-01

    can still induce some antiviral protection, and in vivo depletion of CD8(+) T cells from these animals revealed a pivotal role for CD8(+) T cells in controlling virus replication in the absence of a humoral response. Finally, we demonstrated that effector CD8(+) T cells also contribute to viral......The attenuated yellow fever (YF) vaccine (YF-17D) was developed in the 1930s, yet little is known about the protective mechanisms underlying its efficiency. In this study, we analyzed the relative contribution of cell-mediated and humoral immunity to the vaccine-induced protection in a murine model...... of YF-17D infection. Using different strains of knockout mice, we found that CD4(+) T cells, B cells, and Abs are required for full clinical protection of vaccinated mice, whereas CD8(+) T cells are dispensable for long-term survival after intracerebral challenge. However, by analyzing the immune...

  1. T Cell Help Amplifies Innate Signals in CD8+ DCs for Optimal CD8+ T Cell Priming

    Directory of Open Access Journals (Sweden)

    Marie Greyer

    2016-01-01

    Full Text Available DCs often require stimulation from CD4+ T cells to propagate CD8+ T cell responses, but precisely how T cell help optimizes the priming capacity of DCs and why this appears to differ between varying types of CD8+ T cell immunity remains unclear. We show that CD8+ T cell priming upon HSV-1 skin infection depended on DCs receiving stimulation from both IFN-α/β and CD4+ T cells to provide IL-15. This was not an additive effect but resulted from CD4+ T cells amplifying DC production of IL-15 in response to IFN-α/β. We also observed that increased innate stimulation reversed the helper dependence of CD8+ T cell priming and that the innate stimulus, rather than the CD4+ T cells themselves, determined how “help’” was integrated into the priming response by DCs. These findings identify T cell help as a flexible means to amplify varying suboptimal innate signals in DCs.

  2. Inhibiting glycolytic metabolism enhances CD8+ T cell memory and antitumor function

    Science.gov (United States)

    Sukumar, Madhusudhanan; Liu, Jie; Ji, Yun; Subramanian, Murugan; Crompton, Joseph G.; Yu, Zhiya; Roychoudhuri, Rahul; Palmer, Douglas C.; Muranski, Pawel; Karoly, Edward D.; Mohney, Robert P.; Klebanoff, Christopher A.; Lal, Ashish; Finkel, Toren; Restifo, Nicholas P.; Gattinoni, Luca

    2013-01-01

    Naive CD8+ T cells rely upon oxidation of fatty acids as a primary source of energy. After antigen encounter, T cells shift to a glycolytic metabolism to sustain effector function. It is unclear, however, whether changes in glucose metabolism ultimately influence the ability of activated T cells to become long-lived memory cells. We used a fluorescent glucose analog, 2-NBDG, to quantify glucose uptake in activated CD8+ T cells. We found that cells exhibiting limited glucose incorporation had a molecular profile characteristic of memory precursor cells and an increased capacity to enter the memory pool compared with cells taking up high amounts of glucose. Accordingly, enforcing glycolytic metabolism by overexpressing the glycolytic enzyme phosphoglycerate mutase-1 severely impaired the ability of CD8+ T cells to form long-term memory. Conversely, activation of CD8+ T cells in the presence of an inhibitor of glycolysis, 2-deoxyglucose, enhanced the generation of memory cells and antitumor functionality. Our data indicate that augmenting glycolytic flux drives CD8+ T cells toward a terminally differentiated state, while its inhibition preserves the formation of long-lived memory CD8+ T cells. These results have important implications for improving the efficacy of T cell–based therapies against chronic infectious diseases and cancer. PMID:24091329

  3. Memory CD8+ T cell differentiation in viral infection: A cell for all seasons

    Institute of Scientific and Technical Information of China (English)

    Henry Radziewicz; Luke Uebelhoer; Bertram Bengsch; Arash Grakoui

    2007-01-01

    Chronic viral infections such as hepatitis B virus (HBV),hepatitis C virus (HCV) and human immunodeficiency virus (HIV) are major global health problems affecting more than 500 million people worldwide. Virus-specific CD8+ T cells play an important role in the course and outcome of these viral infections and it is hypothesized that altered or impaired differentiation of virusspecific CD8+ T cells contributes to the development of persistence and/or disease progression. A deeper understanding of the mechanisms responsible for functional differentiation of CD8+ T cells is essential for the generation of successful therapies aiming to strengthen the adaptive component of the immune system.

  4. Perforin and Fas in murine gammaherpesvirus-specific CD8(+) T cell control and morbidity

    DEFF Research Database (Denmark)

    Topham, D J; Cardin, R C; Christensen, Jan Pravsgaard;

    2001-01-01

    The immune system uses both virus-specific T cells and B cells to control the acute and latent phases of respiratory infection with the murine gammaherpesvirus 68 (gammaHV-68). We sought to further define the important effector mechanisms for CD8(+) T cells. First, depletion of the CD4(+) T cells...

  5. The expression of CD8α discriminates distinct T cell subsets in teleost fish.

    Science.gov (United States)

    Takizawa, Fumio; Dijkstra, Johannes Martinus; Kotterba, Paul; Korytář, Tomáš; Kock, Holger; Köllner, Bernd; Jaureguiberry, Beltran; Nakanishi, Teruyuki; Fischer, Uwe

    2011-07-01

    CD8, belonging to the TCR complex, is the main marker molecule of CTLs. Although CD8 genes have been detected in many fish species, the analysis of teleost CD8+ cells has been limited because of the lack of antibodies. Using newly established mAbs against rainbow trout CD8α, we found high ratios of CD8α+ cells in trout thymus, gill and intestine, but relatively low abundance in pronephros, spleen and blood. Accordingly, tissue sections revealed many CD8α+ cells in thymus, numerous intra- and subepithelial CD8α+ cells in intestine and gill and few scattered CD8α+ cells in spleen and pronephros. In secondary lymphoid tissues, CD8α+ lymphocytes, which did not react with anti-thrombocyte or anti-IgM mAbs, expressed CD8α, CD8β and TCRα, while Ig and CD4 transcripts were found in CD8α⁻ lymphocytes. In contrast, considerable CD4 expression in CD8α+ thymocytes suggests the presence of double-positive early T cells. Highly expressed TCRγ, LAG3 and CTLA4 in CD8α+ lymphocytes imply that they constitute a heterogeneous population different from found in non-mucosal tissues. PHA stimulation resulted in an up-regulation of CTL effector genes (perforin, granulysin and IFN-γ) in CD8α+ pronephrocytes, while both Th1 (IFN-γ) and Th2 (IL-4/13A) cytokines were up-regulated in CD8α⁻ pronephrocytes. Although the basic characteristics of CD8α+ lymphocytes seem similar in teleost and mammals, features such as the low proportion of teleost CD8α+ lymphocytes in blood and their high abundance in respiratory tissue reveal a unique dynamics and distribution. PMID:21352850

  6. An IFN-gamma-IL-18 signaling loop accelerates memory CD8+ T cell proliferation.

    Directory of Open Access Journals (Sweden)

    Yoshiko Iwai

    Full Text Available Rapid proliferation is one of the important features of memory CD8(+ T cells, ensuring rapid clearance of reinfection. Although several cytokines such as IL-15 and IL-7 regulate relatively slow homeostatic proliferation of memory T cells during the maintenance phase, it is unknown how memory T cells can proliferate more quickly than naïve T cells upon antigen stimulation. To examine antigen-specific CD8(+ T cell proliferation in recall responses in vivo, we targeted a model antigen, ovalbumin(OVA, to DEC-205(+ dendritic cells (DCs with a CD40 maturation stimulus. This led to the induction of functional memory CD8(+ T cells, which showed rapid proliferation and multiple cytokine production (IFN-gamma, IL-2, TNF-alpha during the secondary challenge to DC-targeted antigen. Upon antigen-presentation, IL-18, an IFN-gamma-inducing factor, accumulated at the DC:T cell synapse. Surprisingly, IFN-gamma receptors were required to augment IL-18 production from DCs. Mice genetically deficient for IL-18 or IFN-gamma-receptor 1 also showed delayed expansion of memory CD8(+ T cells in vivo. These results indicate that a positive regulatory loop involving IFN-gamma and IL-18 signaling contributes to the accelerated memory CD8(+ T cell proliferation during a recall response to antigen presented by DCs.

  7. Molecular Programming of Tumor-Infiltrating CD8+ T Cells and IL15 Resistance.

    Science.gov (United States)

    Doedens, Andrew L; Rubinstein, Mark P; Gross, Emilie T; Best, J Adam; Craig, David H; Baker, Megan K; Cole, David J; Bui, Jack D; Goldrath, Ananda W

    2016-09-01

    Despite clinical potential and recent advances, durable immunotherapeutic ablation of solid tumors is not routinely achieved. IL15 expands natural killer cell (NK), natural killer T cell (NKT) and CD8(+) T-cell numbers and engages the cytotoxic program, and thus is under evaluation for potentiation of cancer immunotherapy. We found that short-term therapy with IL15 bound to soluble IL15 receptor α-Fc (IL15cx; a form of IL15 with increased half-life and activity) was ineffective in the treatment of autochthonous PyMT murine mammary tumors, despite abundant CD8(+) T-cell infiltration. Probing of this poor responsiveness revealed that IL15cx only weakly activated intratumoral CD8(+) T cells, even though cells in the lung and spleen were activated and dramatically expanded. Tumor-infiltrating CD8(+) T cells exhibited cell-extrinsic and cell-intrinsic resistance to IL15. Our data showed that in the case of persistent viral or tumor antigen, single-agent systemic IL15cx treatment primarily expanded antigen-irrelevant or extratumoral CD8(+) T cells. We identified exhaustion, tissue-resident memory, and tumor-specific molecules expressed in tumor-infiltrating CD8(+) T cells, which may allow therapeutic targeting or programming of specific subsets to evade loss of function and cytokine resistance, and, in turn, increase the efficacy of IL2/15 adjuvant cytokine therapy. Cancer Immunol Res; 4(9); 799-811. ©2016 AACR.

  8. Tumor-Induced CD8+ T-Cell Dysfunction in Lung Cancer Patients

    Directory of Open Access Journals (Sweden)

    Heriberto Prado-Garcia

    2012-01-01

    Full Text Available Lung cancer is the leading cause of cancer deaths worldwide and one of the most common types of cancers. The limited success of chemotherapy and radiotherapy regimes have highlighted the need to develop new therapies like antitumor immunotherapy. CD8+ T-cells represent a major arm of the cell-mediated anti-tumor response and a promising target for developing T-cell-based immunotherapies against lung cancer. Lung tumors, however, have been considered to possess poor immunogenicity; even so, lung tumor-specific CD8+ T-cell clones can be established that possess cytotoxicity against autologous tumor cells. This paper will focus on the alterations induced in CD8+ T-cells by lung cancer. Although memory CD8+ T-cells infiltrate lung tumors, in both tumor-infiltrating lymphocytes (TILs and malignant pleural effusions, these cells are dysfunctional and the effector subset is reduced. We propose that chronic presence of lung tumors induces dysfunctions in CD8+ T-cells and sensitizes them to activation-induced cell death, which may be associated with the poor clinical responses observed in immunotherapeutic trials. Getting a deeper knowledge of the evasion mechanisms lung cancer induce in CD8+ T-cells should lead to further understanding of lung cancer biology, overcome tumor evasion mechanisms, and design improved immunotherapeutic treatments for lung cancer.

  9. Qualitative and quantitative analysis of adenovirus type 5 vector-induced memory CD8 T cells

    DEFF Research Database (Denmark)

    Steffensen, Maria Abildgaard; Holst, Peter Johannes; Steengaard, Sanne Skovvang;

    2013-01-01

    It has been reported that adenovirus (Ad) primed CD8 T cells may display a distinct and partially exhausted phenotype. Given the practical implications of this claim, we decided to analyze in detail the quality of Ad-primed CD8 T cells directly comparing these cells to CD8 T cells induced through...... adenoviral boosting and, importantly, the generated secondary memory cells cannot be qualitatively differentiated from those induced by primary infection with replicating virus. Quantitatively, DNA priming prior to Ad-vaccination will lead to even higher numbers of memory cells. In this case, the vaccination...... an effective means to induce a substantially expanded, long-lived population of high-quality transgene-specific memory CD8 T cells....

  10. T cytotoxic-1 CD8+ T cells are effector cells against pneumocystis in mice.

    Science.gov (United States)

    McAllister, Florencia; Mc Allister, Florencia; Steele, Chad; Zheng, Mingquan; Young, Erana; Shellito, Judd E; Marrero, Luis; Kolls, Jay K

    2004-01-15

    Host defenses are profoundly compromised in HIV-infected hosts due to progressive depletion of CD4+ T lymphocytes. A hallmark of HIV infection is Pneumocystis carinii (PC) pneumonia. Recently, CD8+ T cells, which are recruited to the lung in large numbers in response to PC infection, have been associated with some level of host defense as well as contributing to lung injury in BALB/c mice. In this study, we show that CD8+ T cells that have a T cytotoxic-1 response to PC in BALB/c mice, as determined by secretion of IFN-gamma, have in vitro killing activity against PC and effect clearance of the organism in adoptive transfer studies. Moreover, non-T cytotoxic-1 CD8+ T cells lacked in vitro effector activity and contributed to lung injury upon adoptive transfer. This dichotomous response in CD8+ T cell response may in part explain the clinical heterogeneity in the severity of PC pneumonia.

  11. Identification of heme oxygenase-1-specific regulatory CD8+ T cells in cancer patients

    DEFF Research Database (Denmark)

    Andersen, Mads Hald; Sørensen, Rikke Baek; Brimnes, Marie K;

    2009-01-01

    the antigens they recognize. Here, we describe what we believe to be the first natural target for CD8+ Tregs. Naturally occurring HLA-A2-restricted CD8+ T cells specific for the antiinflammatory molecule heme oxygenase-1 (HO-1) were able to suppress cellular immune responses with outstanding efficacy...

  12. Peripheral tolerance through clonal deletion of mature CD4-CD8+ T cells.

    Science.gov (United States)

    Carlow, D A; Teh, S J; van Oers, N S; Miller, R G; Teh, H S

    1992-05-01

    Transgenic mice bearing the alpha beta transgenes encoding a defined T cell receptor specific for the male (H-Y) antigen presented by the H-2Db class I MHC molecule were used to study mechanisms of peripheral tolerance. Female transgenic mice produce large numbers of functionally homogeneous CD8+ male antigen-reactive T cells in the thymus that subsequently accumulate in the peripheral lymphoid organs. We have used three experimental approaches to show that male reactive CD8+ T cells can be eliminated from peripheral lymphoid organs after exposure to male antigen. (i) In female transgenic mice that were neonatally tolerized with male spleen cells, male reactive CD8+ T cells continued to be produced in large numbers in the thymus but were virtually absent in the lymph nodes. (ii) Injection of thymocytes from female transgenic mice into female mice neonatally tolerized with the male antigen, or into normal male mice, led to the specific elimination of male-reactive CD8+ T cells in the lymph nodes. (iii) Four days after male lymphoid cells were injected intravenously into female transgenic mice, male antigen-reactive CD8+ T cells recovered from the lymph nodes of recipient mice were highly apoptotic when compared to CD4+ (non-male reactive) T cells. These data indicate that tolerance to extrathymic antigen can be achieved through elimination of mature T cells in the peripheral lymphoid organs.

  13. Kinetics and Phenotype of Vaccine-Induced CD8+ T-Cell Responses to Toxoplasma gondii▿

    OpenAIRE

    Jordan, Kimberly A.; Wilson, Emma H.; Tait, Elia D.; Fox, Barbara A.; Roos, David S.; Bzik, David J.; Dzierszinski, Florence; Hunter, Christopher A.

    2009-01-01

    Multiple studies have established that the ability of CD8+ T cells to act as cytolytic effectors and produce gamma interferon is important in mediating resistance to the intracellular parasite Toxoplasma gondii. To better understand the generation of the antigen-specific CD8+ T-cell responses induced by T. gondii, mice were immunized with replication-deficient parasites that express the model antigen ovalbumin (OVA). Class I tetramers specific for SIINFEKL were used to track the OVA-specific ...

  14. A distinct subset of self-renewing human memory CD8+ T cells survives cytotoxic chemotherapy

    OpenAIRE

    Turtle, Cameron J.; Swanson, Hillary M.; Fujii, Nobuharu; Estey, Elihu H.; Riddell, Stanley R.

    2009-01-01

    The mechanisms that maintain human T cell memory during normal and perturbed homeostasis are not fully understood. The repeated induction of profound lymphocytopenia in patients undergoing multiple cycles of cytotoxic chemotherapy infrequently results in severe infections with viruses controlled by memory T cells, suggesting that some memory T cells survive chemotherapy and restore immunity. Here we identify a distinct subpopulation of memory CD8+ T cells with the ability to rapidly efflux an...

  15. Recombinant yellow fever viruses elicit CD8+ T cell responses and protective immunity against Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Raquel Tayar Nogueira

    Full Text Available Chagas' disease is a major public health problem affecting nearly 10 million in Latin America. Despite several experimental vaccines have shown to be immunogenic and protective in mouse models, there is not a current vaccine being licensed for humans or in clinical trial against T. cruzi infection. Towards this goal, we used the backbone of Yellow Fever (YF 17D virus, one of the most effective and well-established human vaccines, to express an immunogenic fragment derived from T. cruzi Amastigote Surface Protein 2 (ASP-2. The cDNA sequence of an ASP-2 fragment was inserted between E and NS1 genes of YF 17D virus through the construction of a recombinant heterologous cassette. The replication ability and genetic stability of recombinant YF virus (YF17D/ENS1/Tc was confirmed for at least six passages in Vero cells. Immunogenicity studies showed that YF17D/ENS1/Tc virus elicited neutralizing antibodies and gamma interferon (IFN-γ producing-cells against the YF virus. Also, it was able to prime a CD8(+ T cell directed against the transgenic T. cruzi epitope (TEWETGQI which expanded significantly as measured by T cell-specific production of IFN-γ before and after T. cruzi challenge. However, most important for the purposes of vaccine development was the fact that a more efficient protective response could be seen in mice challenged after vaccination with the YF viral formulation consisting of YF17D/ENS1/Tc and a YF17D recombinant virus expressing the TEWETGQI epitope at the NS2B-3 junction. The superior protective immunity observed might be due to an earlier priming of epitope-specific IFN-γ-producing T CD8(+ cells induced by vaccination with this viral formulation. Our results suggest that the use of viral formulations consisting of a mixture of recombinant YF 17D viruses may be a promising strategy to elicit protective immune responses against pathogens, in general.

  16. Regulation of CD8+ T cell responses to retinal antigen by local FoxP3+ regulatory T cells

    Directory of Open Access Journals (Sweden)

    Scott W McPherson

    2012-06-01

    Full Text Available While pathogenic CD4 T cells are well known mediators of autoimmune uveoretinitis, CD8 T cells can also be uveitogenic. Since preliminary studies indicated that C57BL/6 mice were minimally susceptible to autoimmune uveoretinitis induction by CD8 T cells, the basis of the retinal disease resistance was sought. Mice that express β-galactosidase (βgal on a retina-specific promoter (arrβgal mice were backcrossed to mice expressing green fluorescent protein and diphtheria toxin receptor under control of the Foxp3 promoter (Foxp3-DTR/GFP mice, and to T cell receptor transgenic mice that produce βgal specific CD8 T cells (BG1 mice. These mice were used to explore the role of regulatory T cells in the resistance to retinal autoimmune disease. Experiments with T cells from double transgenic BG1 x Foxp3-DTR/GFP mice transferred into Foxp3-DTR/GFP x arrβgal mice confirmed that the retina was well protected from attempts to induce disease by adoptive transfer of activated BG1 T cells. The successful induction of retinal disease following unilateral intraocular administration of diphtheria toxin to deplete regulatory T cells showed that the protective activity was dependent on local, toxin-sensitive regulatory T cells; the opposite, untreated eye remained disease-free. Although there were very few Foxp3+ regulatory T cells in the parenchyma of quiescent retina, and they did not accumulate in retina, their depletion by local toxin administration led to disease susceptibility. We propose that these regulatory T cells modulate the pathogenic activity of βgal-specific CD8 T cells in the retinas of arrβgal mice on a local basis, allowing immunoregulation to be responsive to local conditions.

  17. Salmonella impairs CD8 T cell response through PD-1: PD-L axis.

    Science.gov (United States)

    López-Medina, Marcela; Carrillo-Martín, Ismael; Leyva-Rangel, Jessica; Alpuche-Aranda, Celia; Ortiz-Navarrete, Vianney

    2015-12-01

    We have shown that Salmonella remains for a long period of time within B cells, plasma cells, and bone marrow B cell precursors, which might allow persistence and dissemination of infection. Nonetheless, how infected cells evade CD8 T cell response has not been characterized. Evidence indicates that some pathogens exploit the PD-1: PD-L (PD-L1 and PD-L2) interaction to inhibit CD8 T cells response to contribute the chronicity of the infection. To determine whether the PD-1: PD-L axis plays a role during Salmonella infection; we evaluated PD-1 expression in antigen-specific CD8 T cells and PD-1 ligands in Salmonella-infected cells. Our results show that infected B cells and macrophages express continuously co-stimulatory (CD40, CD80, and CD86) and inhibitory molecules (PD-L1 and PD-L2) in early and late stages of chronic Salmonella infection, while antigen-specific CD8 T cells express in a sustained manner PD-1 in the late stages of infection. Blocking this axis restores the ability of the CD8 T cells to proliferate and eliminate primary infected APCs. Therefore, a continuous PD-1: PDL interaction might be a mechanism employed by Salmonella to negatively regulate Salmonella-specific CD8 T cell cytotoxic response in order to remain within the host for a long period of time.

  18. Specific immunotherapy generates CD8(+) CD196(+) T cells to suppress lung cancer growth in mice.

    Science.gov (United States)

    Zhang, Jian; Liu, Jing; Chen, Huiguo; Wu, Weibin; Li, Xiaojun; Wu, Yonghui; Wang, Zhigang; Zhang, Kai; Li, Yun; Weng, Yimin; Liao, Hongying; Gu, Lijia

    2016-08-01

    That specific immunotherapy can inhibit cancer growth has been recognized; its efficiency is to be improved. This study aimed to inhibit lung cancer (LC) growth in a mouse model by using an LC-specific vaccination. In this study, a LC mouse model was created by adoptive transplantation with LC cells. The tumor-bearing mice were vaccinated with LC cell extracts plus adjuvant TNBS or adoptive transplantation with specific CD8(+) CD196(+) T cells. The results showed that the vaccination with LC extracts (LCE)/TNBS markedly inhibited the LC growth and induced CD8(+) CD196(+) T cells in LC tissue and the spleen. These CD8(+) CD196(+) T cells proliferated and produce high levels of perforin upon exposure to LCE and specifically induced LC cell apoptosis. Exposure to TNBS induced RAW264.7 cells to produce macrophage inflammatory protein-3α; the latter activated signal transducer and activator of transcription 3 and further induced perforin expression in the CD8(+) CD196(+) T cells. Adoptive transfer with specific CD8(+) CD196(+) T cells suppressed LC growth in mice. In conclusion, immunization with LC extracts and TNBS can induce LC-specific CD8(+) CD196(+) T cells in LC-bearing mice and inhibit LC growth. PMID:26910585

  19. Adoptive immunotherapy of cancer with polyclonal, 108-fold hyperexpanded, CD4+ and CD8+ T cells

    Directory of Open Access Journals (Sweden)

    Kim Julian A

    2004-11-01

    Full Text Available Abstract T cell-mediated cancer immunotherapy is dose dependent and optimally requires participation of antigen-specific CD4+ and CD8+ T cells. Here, we isolated tumor-sensitized T cells and activated them in vitro using conditions that led to greater than 108-fold numerical hyperexpansion of either the CD4+ or CD8+ subset while retaining their capacity for in vivo therapeutic efficacy. Murine tumor-draining lymph node (TDLN cells were segregated to purify the CD62Llow subset, or the CD4+ subset thereof. Cells were then propagated through multiple cycles of anti-CD3 activation with IL-2 + IL-7 for the CD8+ subset, or IL-7 + IL-23 for the CD4+ subset. A broad repertoire of TCR Vβ families was maintained throughout hyperexpansion, which was similar to the starting population. Adoptive transfer of hyper-expanded CD8+ T cells eliminated established pulmonary metastases, in an immunologically specific fashion without the requirement for adjunct IL-2. Hyper-expanded CD4+ T cells cured established tumors in intracranial or subcutaneous sites that were not susceptible to CD8+ T cells alone. Because accessibility and antigen presentation within metastases varies according to anatomic site, maintenance of a broad repertoire of both CD4+ and CD8+ T effector cells will augment the overall systemic efficacy of adoptive immunotherapy.

  20. Epitope specific T-cell responses against influenza A in a healthy population.

    Science.gov (United States)

    Savic, Miloje; Dembinski, Jennifer L; Kim, Yohan; Tunheim, Gro; Cox, Rebecca J; Oftung, Fredrik; Peters, Bjoern; Mjaaland, Siri

    2016-02-01

    Pre-existing human CD4(+) and CD8(+) T-cell-mediated immunity may be a useful correlate of protection against severe influenza disease. Identification and evaluation of common epitopes recognized by T cells with broad cross-reactivity is therefore important to guide universal influenza vaccine development, and to monitor immunological preparedness against pandemics. We have retrieved an optimal combination of MHC class I and class II restricted epitopes from the Immune Epitope Database (www.iedb.org), by defining a fitness score function depending on prevalence, sequence conservancy and HLA super-type coverage. Optimized libraries of CD4(+) and CD8(+) T-cell epitopes were selected from influenza antigens commonly present in seasonal and pandemic influenza strains from 1934 to 2009. These epitope pools were used to characterize human T-cell responses in healthy donors using interferon-γ ELISPOT assays. Upon stimulation, significant CD4(+) and CD8(+) T-cell responses were induced, primarily recognizing epitopes from the conserved viral core proteins. Furthermore, the CD4(+) and CD8(+) T cells were phenotypically characterized regarding functionality, cytotoxic potential and memory phenotype using flow cytometry. Optimized sets of T-cell peptide epitopes may be a useful tool to monitor the efficacy of clinical trials, the immune status of a population to predict immunological preparedness against pandemics, as well as being candidates for universal influenza vaccines. PMID:26489873

  1. Kinetics and phenotype of vaccine-induced CD8+ T-cell responses to Toxoplasma gondii.

    Science.gov (United States)

    Jordan, Kimberly A; Wilson, Emma H; Tait, Elia D; Fox, Barbara A; Roos, David S; Bzik, David J; Dzierszinski, Florence; Hunter, Christopher A

    2009-09-01

    Multiple studies have established that the ability of CD8(+) T cells to act as cytolytic effectors and produce gamma interferon is important in mediating resistance to the intracellular parasite Toxoplasma gondii. To better understand the generation of the antigen-specific CD8(+) T-cell responses induced by T. gondii, mice were immunized with replication-deficient parasites that express the model antigen ovalbumin (OVA). Class I tetramers specific for SIINFEKL were used to track the OVA-specific endogenous CD8(+) T cells. The peak CD8(+) T-cell response was found at day 10 postimmunization, after which the frequency and numbers of antigen-specific cells declined. Unexpectedly, replication-deficient parasites were found to induce antigen-specific cells with faster kinetics than replicating parasites. The generation of optimal numbers of antigen-specific CD8(+) effector T cells was found to require CD4(+) T-cell help. At 7 days following immunization, antigen-specific cells were found to be CD62L(low), KLRG1(+), and CD127(low), and they maintained this phenotype for more than 70 days. Antigen-specific CD8(+) effector T cells in immunized mice exhibited potent perforin-dependent OVA-specific cytolytic activity in vivo. Perforin-dependent cytolysis appeared to be the major cytolytic mechanism; however, a perforin-independent pathway that was not mediated via Fas-FasL was also detected. This study provides further insight into vaccine-induced cytotoxic T-lymphocyte responses that correlate with protective immunity to T. gondii and identifies a critical role for CD4(+) T cells in the generation of protective CD8(+) T-cell responses. PMID:19528214

  2. Kinetics and Phenotype of Vaccine-Induced CD8+ T-Cell Responses to Toxoplasma gondii▿

    Science.gov (United States)

    Jordan, Kimberly A.; Wilson, Emma H.; Tait, Elia D.; Fox, Barbara A.; Roos, David S.; Bzik, David J.; Dzierszinski, Florence; Hunter, Christopher A.

    2009-01-01

    Multiple studies have established that the ability of CD8+ T cells to act as cytolytic effectors and produce gamma interferon is important in mediating resistance to the intracellular parasite Toxoplasma gondii. To better understand the generation of the antigen-specific CD8+ T-cell responses induced by T. gondii, mice were immunized with replication-deficient parasites that express the model antigen ovalbumin (OVA). Class I tetramers specific for SIINFEKL were used to track the OVA-specific endogenous CD8+ T cells. The peak CD8+ T-cell response was found at day 10 postimmunization, after which the frequency and numbers of antigen-specific cells declined. Unexpectedly, replication-deficient parasites were found to induce antigen-specific cells with faster kinetics than replicating parasites. The generation of optimal numbers of antigen-specific CD8+ effector T cells was found to require CD4+ T-cell help. At 7 days following immunization, antigen-specific cells were found to be CD62Llow, KLRG1+, and CD127low, and they maintained this phenotype for more than 70 days. Antigen-specific CD8+ effector T cells in immunized mice exhibited potent perforin-dependent OVA-specific cytolytic activity in vivo. Perforin-dependent cytolysis appeared to be the major cytolytic mechanism; however, a perforin-independent pathway that was not mediated via Fas-FasL was also detected. This study provides further insight into vaccine-induced cytotoxic T-lymphocyte responses that correlate with protective immunity to T. gondii and identifies a critical role for CD4+ T cells in the generation of protective CD8+ T-cell responses. PMID:19528214

  3. CD8{sup +}CD25{sup +} T cells reduce atherosclerosis in apoE(−/−) mice

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianchang; Dimayuga, Paul C.; Zhao, Xiaoning; Yano, Juliana; Lio, Wai Man; Trinidad, Portia; Honjo, Tomoyuki; Cercek, Bojan; Shah, Prediman K.; Chyu, Kuang-Yuh, E-mail: Chyuk@cshs.org

    2014-01-17

    Highlights: •The role of a sub-population of CD8{sup +} T cells with suppressor functions was investigated in atherosclerosis. •CD8{sup +}CD25{sup +} T cells from adult apoE(−/−) mice had phenotype characteristics of T suppressor cells. •These CD8{sup +}CD25{sup +} T cells reduced CD4{sup +} T cell proliferation and CD8{sup +} cytotoxic activity in vitro. •Adoptive transfer of CD8{sup +}CD25{sup +} T cells significantly reduced atherosclerosis. •CD8{sup +}CD25{sup +} T cells have a suppressive function in atherosclerosis. -- Abstract: Background: It is increasingly evident that CD8{sup +} T cells are involved in atherosclerosis but the specific subtypes have yet to be defined. CD8{sup +}CD25{sup +} T cells exert suppressive effects on immune signaling and modulate experimental autoimmune disorders but their role in atherosclerosis remains to be determined. The phenotype and functional role of CD8{sup +}CD25{sup +} T cells in experimental atherosclerosis were investigated in this study. Methods and results: CD8{sup +}CD25{sup +} T cells were observed in atherosclerotic plaques of apoE(−/−) mice fed hypercholesterolemic diet. Characterization by flow cytometric analysis and functional evaluation using a CFSE-based proliferation assays revealed a suppressive phenotype and function of splenic CD8{sup +}CD25{sup +} T cells from apoE(−/−) mice. Depletion of CD8{sup +}CD25{sup +} from total CD8{sup +} T cells rendered higher cytolytic activity of the remaining CD8{sup +}CD25{sup −} T cells. Adoptive transfer of CD8{sup +}CD25{sup +} T cells into apoE(−/−) mice suppressed the proliferation of splenic CD4{sup +} T cells and significantly reduced atherosclerosis in recipient mice. Conclusions: Our study has identified an athero-protective role for CD8{sup +}CD25{sup +} T cells in experimental atherosclerosis.

  4. PSGL-1 regulates the migration and proliferation of CD8(+) T cells under homeostatic conditions.

    Science.gov (United States)

    Veerman, Krystle M; Carlow, Douglas A; Shanina, Iryna; Priatel, John J; Horwitz, Marc S; Ziltener, Hermann J

    2012-02-15

    P-selectin glycoprotein ligand-1 (PSGL-1), a heavily glycosylated sialomucin expressed on most leukocytes, has dual function as a selectin ligand for leukocyte rolling on vascular selectins expressed in inflammation and as a facilitator of resting T cell homing into lymphoid organs. In this article, we document disturbances in T cell homeostasis present in PSGL-1(null) mice. Naive CD4(+) and CD8(+) T cell frequencies were profoundly reduced in blood, whereas T cell numbers in lymph nodes and spleen were at or near normal levels. Although PSGL-1(null) T cells were less efficient at entering lymph nodes, they also remained in lymph nodes longer than PSGL-1(+/+) T cells, suggesting that PSGL-1 supports T cell egress. In addition, PSGL-1(null) CD8(+) T cell proliferation was observed under steady-state conditions and PSGL-1(null) CD8(+) T cells were found to be hyperresponsive to homeostatic cytokines IL-2, IL-4, and IL-15. Despite these disturbances in T cell homeostasis, PSGL-1(null) mice exhibited a normal acute response (day 8) to lymphocytic choriomeningitis virus infection but generated an increased frequency of memory T cells (day 40). Our observations demonstrate a novel pleiotropic influence of PSGL-1 deficiency on several aspects of T cell homeostasis that would not have been anticipated based on the mild phenotype of PSGL-1(null) mice. These potentially offsetting effects presumably account for the near-normal cellularity seen in lymph nodes of PSGL-1(null) mice.

  5. Thymoproteasomes produce unique peptide motifs for positive selection of CD8(+) T cells.

    Science.gov (United States)

    Sasaki, Katsuhiro; Takada, Kensuke; Ohte, Yuki; Kondo, Hiroyuki; Sorimachi, Hiroyuki; Tanaka, Keiji; Takahama, Yousuke; Murata, Shigeo

    2015-01-01

    Positive selection in the thymus provides low-affinity T-cell receptor (TCR) engagement to support the development of potentially useful self-major histocompatibility complex class I (MHC-I)-restricted T cells. Optimal positive selection of CD8(+) T cells requires cortical thymic epithelial cells that express β5t-containing thymoproteasomes (tCPs). However, how tCPs govern positive selection is unclear. Here we show that the tCPs produce unique cleavage motifs in digested peptides and in MHC-I-associated peptides. Interestingly, MHC-I-associated peptides carrying these tCP-dependent motifs are enriched with low-affinity TCR ligands that efficiently induce the positive selection of functionally competent CD8(+) T cells in antigen-specific TCR-transgenic models. These results suggest that tCPs contribute to the positive selection of CD8(+) T cells by preferentially producing low-affinity TCR ligand peptides.

  6. Exhaustion of Activated CD8 T Cells Predicts Disease Progression in Primary HIV-1 Infection.

    Science.gov (United States)

    Hoffmann, Matthias; Pantazis, Nikos; Martin, Genevieve E; Hickling, Stephen; Hurst, Jacob; Meyerowitz, Jodi; Willberg, Christian B; Robinson, Nicola; Brown, Helen; Fisher, Martin; Kinloch, Sabine; Babiker, Abdel; Weber, Jonathan; Nwokolo, Nneka; Fox, Julie; Fidler, Sarah; Phillips, Rodney; Frater, John

    2016-07-01

    The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n = 122) recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression. Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL) and CD4 T cell count) and the trial endpoint (time to CD4 count approaches. PMID:27415828

  7. Impact of clonal competition for peptide-MHC complexes on the CD8[superscript +] T-cell repertoire selection in a persistent viral infection

    Energy Technology Data Exchange (ETDEWEB)

    Wynn, Katherine K.; Fulton, Zara; Cooper, Leanne; Silins, Sharon L.; Gras, Stephanie; Archbold, Julia K.; Tynan, Fleur E.; Miles, John J.; McCluskey, James; Burrows, Scott R.; Rossjohn, Jamie; Khanna, Rajiv (Monash); (Queensland Inst. of Med. Rsrch.); (Melbourne)

    2008-04-29

    CD8{sup +} T-cell responses to persistent viral infections are characterized by the accumulation of an oligoclonal T-cell repertoire and a reduction in the naive T-cell pool. However, the precise mechanism for this phenomenon remains elusive. Here we show that human cytomegalovirus (HCMV)-specific CD8{sup +} T cells recognizing distinct epitopes from the pp65 protein and restricted through an identical HLA class I allele (HLA B*3508) exhibited either a highly conserved public T-cell repertoire or a private, diverse T-cell response, which was uniquely altered in each donor following in vitro antigen exposure. Selection of a public T-cell receptor (TCR) was coincident with an atypical major histocompatibility complex (MHC)-peptide structure, in that the epitope adopted a helical conformation that bulged from the peptide-binding groove, while a diverse TCR profile was observed in response to the epitope that formed a flatter, more 'featureless' landscape. Clonotypes with biased TCR usage demonstrated more efficient recognition of virus-infected cells, a greater CD8 dependency, and were more terminally differentiated in their phenotype when compared with the T cells expressing diverse TCR. These findings provide new insights into our understanding on how the biology of antigen presentation in addition to the structural features of the pMHC-I might shape the T-cell repertoire and its phenotype.

  8. IL-17A secretion by CD8+ T cells supports Th17-mediated autoimmune encephalomyelitis

    OpenAIRE

    Huber, Magdalena; Heink, Sylvia; Pagenstecher, Axel; Reinhard, Katharina; Ritter, Josephine; Visekruna, Alexander; Guralnik, Anna; Bollig, Nadine; Jeltsch, Katharina; Heinemann, Christina; Wittmann, Eva; Buch, Thorsten; da Costa, Olivia Prazeres; Brüstle, Anne; Brenner, Dirk

    2012-01-01

    IL-17–producing CD8+ T (Tc17) cells are detectible in multiple sclerosis (MS) lesions; however, their contribution to the disease is unknown. To identify functions of Tc17 cells, we induced EAE, a murine model of MS, in mice lacking IFN regulatory factor 4 (IRF4). IRF4-deficient mice failed to generate Tc17 and Th17 cells and were resistant to EAE. After adoptive transfer of WT CD8+ T cells and subsequent immunization for EAE induction in these mice, the CD8+ T cells developed a Tc17 phenotyp...

  9. Immunological tolerance to muscle autoantigens involves peripheral deletion of autoreactive CD8+ T cells.

    Directory of Open Access Journals (Sweden)

    Emilie Franck

    Full Text Available Muscle potentially represents the most abundant source of autoantigens of the body and can be targeted by a variety of severe autoimmune diseases. Yet, the mechanisms of immunological tolerance toward muscle autoantigens remain mostly unknown. We investigated this issue in transgenic SM-Ova mice that express an ovalbumin (Ova neo-autoantigen specifically in skeletal muscle. We previously reported that antigen specific CD4(+ T cell are immunologically ignorant to endogenous Ova in this model but can be stimulated upon immunization. In contrast, Ova-specific CD8(+ T cells were suspected to be either unresponsive to Ova challenge or functionally defective. We now extend our investigations on the mechanisms governing CD8(+ tolerance in SM-Ova mice. We show herein that Ova-specific CD8(+ T cells are not detected upon challenge with strongly immunogenic Ova vaccines even after depletion of regulatory T cells. Ova-specific CD8(+ T cells from OT-I mice adoptively transferred to SM-Ova mice started to proliferate in vivo, acquired CD69 and PD-1 but subsequently down-regulated Bcl-2 and disappeared from the periphery, suggesting a mechanism of peripheral deletion. Peripheral deletion of endogenous Ova-specific cells was formally demonstrated in chimeric SM-Ova mice engrafted with bone marrow cells containing T cell precursors from OT-I TCR-transgenic mice. Thus, the present findings demonstrate that immunological tolerance to muscle autoantigens involves peripheral deletion of autoreactive CD8(+ T cells.

  10. Dynamic Imaging of CD8(+) T cells and dendritic cells during infection with Toxoplasma gondii.

    Science.gov (United States)

    John, Beena; Harris, Tajie H; Tait, Elia D; Wilson, Emma H; Gregg, Beth; Ng, Lai Guan; Mrass, Paulus; Roos, David S; Dzierszinski, Florence; Weninger, Wolfgang; Hunter, Christopher A

    2009-07-01

    To better understand the initiation of CD8(+) T cell responses during infection, the primary response to the intracellular parasite Toxoplasma gondii was characterized using 2-photon microscopy combined with an experimental system that allowed visualization of dendritic cells (DCs) and parasite specific CD8(+) T cells. Infection with T. gondii induced localization of both these populations to the sub-capsular/interfollicular region of the draining lymph node and DCs were required for the expansion of the T cells. Consistent with current models, in the presence of cognate antigen, the average velocity of CD8(+) T cells decreased. Unexpectedly, infection also resulted in modulation of the behavior of non-parasite specific T cells. This TCR-independent process correlated with the re-modeling of the lymph node micro-architecture and changes in expression of CCL21 and CCL3. Infection also resulted in sustained interactions between the DCs and CD8(+) T cells that were visualized only in the presence of cognate antigen and were limited to an early phase in the response. Infected DCs were rare within the lymph node during this time frame; however, DCs presenting the cognate antigen were detected. Together, these data provide novel insights into the earliest interaction between DCs and CD8(+) T cells and suggest that cross presentation by bystander DCs rather than infected DCs is an important route of antigen presentation during toxoplasmosis.

  11. Dynamic Imaging of CD8(+ T cells and dendritic cells during infection with Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Beena John

    2009-07-01

    Full Text Available To better understand the initiation of CD8(+ T cell responses during infection, the primary response to the intracellular parasite Toxoplasma gondii was characterized using 2-photon microscopy combined with an experimental system that allowed visualization of dendritic cells (DCs and parasite specific CD8(+ T cells. Infection with T. gondii induced localization of both these populations to the sub-capsular/interfollicular region of the draining lymph node and DCs were required for the expansion of the T cells. Consistent with current models, in the presence of cognate antigen, the average velocity of CD8(+ T cells decreased. Unexpectedly, infection also resulted in modulation of the behavior of non-parasite specific T cells. This TCR-independent process correlated with the re-modeling of the lymph node micro-architecture and changes in expression of CCL21 and CCL3. Infection also resulted in sustained interactions between the DCs and CD8(+ T cells that were visualized only in the presence of cognate antigen and were limited to an early phase in the response. Infected DCs were rare within the lymph node during this time frame; however, DCs presenting the cognate antigen were detected. Together, these data provide novel insights into the earliest interaction between DCs and CD8(+ T cells and suggest that cross presentation by bystander DCs rather than infected DCs is an important route of antigen presentation during toxoplasmosis.

  12. HIV-Specific CD8+ T Cell-Mediated Viral Suppression Correlates With the Expression of CD57

    DEFF Research Database (Denmark)

    Jensen, Sanne S; Tingstedt, Jeanette Linnea; Larsen, Tine Kochendorf;

    2016-01-01

    BACKGROUND: Virus-specific CD8(+) T-cell responses are believed to play an important role in the control of HIV-1 infection; however, what constitutes an effective HIV-1 CD8(+) T-cell response remains a topic of debate. The ex vivo viral suppressive capacity was measured of CD8(+) T cells from 44...

  13. Regulatory T cells prevent CD8 T cell maturation by inhibiting CD4 Th cells at tumor sites.

    Science.gov (United States)

    Chaput, Nathalie; Darrasse-Jèze, Guillaume; Bergot, Anne-Sophie; Cordier, Corinne; Ngo-Abdalla, Stacie; Klatzmann, David; Azogui, Orly

    2007-10-15

    Natural regulatory T cells (Tregs) are present in high frequencies among tumor-infiltrating lymphocytes and in draining lymph nodes, supposedly facilitating tumor development. To investigate their role in controlling local immune responses, we analyzed intratumoral T cell accumulation and function in the presence or absence of Tregs. Tumors that grew in normal BALB/c mice injected with the 4T1 tumor cell line were highly infiltrated by Tregs, CD4 and CD8 cells, all having unique characteristics. Most infiltrating Tregs expressed low levels of CD25Rs and Foxp3. They did not proliferate even in the presence of IL-2 but maintained a strong suppressor activity. CD4 T cells were profoundly anergic and CD8 T cell proliferation and cytotoxicity were severely impaired. Depletion of Tregs modified the characteristics of tumor infiltrates. Tumors were initially invaded by activated CD4(+)CD25(-) T cells, which produced IL-2 and IFN-gamma. This was followed by the recruitment of highly cytotoxic CD8(+) T cells at tumor sites leading to tumor rejection. The beneficial effect of Treg depletion in tumor regression was abrogated when CD4 helper cells were also depleted. These findings indicate that the massive infiltration of tumors by Tregs prevents the development of a successful helper response. The Tregs in our model prevent Th cell activation and subsequent development of efficient CD8 T cell activity required for the control of tumor growth. PMID:17911581

  14. Praziquantel facilitates IFN-γ-producing CD8+ T cells (Tc1 and IL-17-producing CD8+ T cells (Tc17 responses to DNA vaccination in mice.

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    Qiang Zou

    Full Text Available BACKGROUND: CD8(+ cytotoxic T lymphocytes (CTLs are crucial for eliminating hepatitis B virus (HBV infected cells. DNA vaccination, a novel therapeutic strategy for chronic virus infection, has been shown to induce CTL responses. However, accumulated data have shown that CTLs could not be effectively induced by HBV DNA vaccination. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that praziquantel (PZQ, an anti-schistoma drug, could act as an adjuvant to overcome the lack of potent CTL responses by HBV DNA vaccination in mice. PZQ in combination with HBV DNA vaccination augmented the induction of CD8(+ T cell-dependent and HBV-specific delayed hypersensitivity responses (DTH in C57BL/6 mice. Furthermore, the induced CD8(+ T cells consisted of both Tc1 and Tc17 subtypes. By using IFN-γ knockout (KO mice and IL-17 KO mice, both cytokines were found to be involved in the DTH. The relevance of these findings to HBV immunization was established in HBsAg transgenic mice, in which PZQ also augmented the induction of HBV-specific Tc1 and Tc17 cells and resulted in reduction of HBsAg positive hepatocytes. Adoptive transfer experiments further showed that PZQ-primed CD8(+ T cells from wild type mice, but not the counterpart from IFN-γ KO or IL-17 KO mice, resulted in elimination of HBsAg positive hepatocytes. CONCLUSIONS/SIGNIFICANCE: Our results suggest that PZQ is an effective adjuvant to facilitate Tc1 and Tc17 responses to HBV DNA vaccination, inducing broad CD8(+ T cell-based immunotherapy that breaks tolerance to HBsAg.

  15. Phenotypic and Functional Alterations in Circulating Memory CD8 T Cells with Time after Primary Infection.

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    Matthew D Martin

    2015-10-01

    Full Text Available Memory CD8 T cells confer increased protection to immune hosts upon secondary viral, bacterial, and parasitic infections. The level of protection provided depends on the numbers, quality (functional ability, and location of memory CD8 T cells present at the time of infection. While primary memory CD8 T cells can be maintained for the life of the host, the full extent of phenotypic and functional changes that occur over time after initial antigen encounter remains poorly characterized. Here we show that critical properties of circulating primary memory CD8 T cells, including location, phenotype, cytokine production, maintenance, secondary proliferation, secondary memory generation potential, and mitochondrial function change with time after infection. Interestingly, phenotypic and functional alterations in the memory population are not due solely to shifts in the ratio of effector (CD62Llo and central memory (CD62Lhi cells, but also occur within defined CD62Lhi memory CD8 T cell subsets. CD62Lhi memory cells retain the ability to efficiently produce cytokines with time after infection. However, while it is was not formally tested whether changes in CD62Lhi memory CD8 T cells over time occur in a cell intrinsic manner or are due to selective death and/or survival, the gene expression profiles of CD62Lhi memory CD8 T cells change, phenotypic heterogeneity decreases, and mitochondrial function and proliferative capacity in either a lymphopenic environment or in response to antigen re-encounter increase with time. Importantly, and in accordance with their enhanced proliferative and metabolic capabilities, protection provided against chronic LCMV clone-13 infection increases over time for both circulating memory CD8 T cell populations and for CD62Lhi memory cells. Taken together, the data in this study reveal that memory CD8 T cells continue to change with time after infection and suggest that the outcome of vaccination strategies designed to elicit

  16. Identification and HLA-tetramer-validation of human CD4+ and CD8+ T cell responses against HCMV proteins IE1 and IE2.

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    Peter Braendstrup

    Full Text Available Human cytomegalovirus (HCMV is an important human pathogen. It is a leading cause of congenital infection and a leading infectious threat to recipients of solid organ transplants as well as of allogeneic hematopoietic cell transplants. Moreover, it has recently been suggested that HCMV may promote tumor development. Both CD4+ and CD8+ T cell responses are important for long-term control of the virus, and adoptive transfer of HCMV-specific T cells has led to protection from reactivation and HCMV disease. Identification of HCMV-specific T cell epitopes has primarily focused on CD8+ T cell responses against the pp65 phosphoprotein. In this study, we have focused on CD4+ and CD8+ T cell responses against the immediate early 1 and 2 proteins (IE1 and IE2. Using overlapping peptides spanning the entire IE1 and IE2 sequences, peripheral blood mononuclear cells from 16 healthy, HLA-typed, donors were screened by ex vivo IFN-γ ELISpot and in vitro intracellular cytokine secretion assays. The specificities of CD4+ and CD8+ T cell responses were identified and validated by HLA class II and I tetramers, respectively. Eighty-one CD4+ and 44 CD8+ T cell responses were identified representing at least seven different CD4 epitopes and 14 CD8 epitopes restricted by seven and 11 different HLA class II and I molecules, respectively, in total covering 91 and 98% of the Caucasian population, respectively. Presented in the context of several different HLA class II molecules, two epitope areas in IE1 and IE2 were recognized in about half of the analyzed donors. These data may be used to design a versatile anti-HCMV vaccine and/or immunotherapy strategy.

  17. Differential remodeling of a T-cell transcriptome following CD8-versus CD3-induced signaling

    Institute of Scientific and Technical Information of China (English)

    S Hussain I Abidi; Tao Dong; Mai T Vuong; Vattipally B Sreenu; Sarah L Rowland-Jones; Edward J Evans; Simon J Davis

    2008-01-01

    CD8 engagement with class I major histocompatibility antigens greatly enhances T-cell activation,but it is not clear how this is achieved.We address the question of whether or not the antibody-mediated ligation of CD8 alone induces transcriptional remodeling in a T-cell clone,using serial analysis of gene expression.Even though it fails to induce overt phenotypic changes,we find that CD8 ligation profoundly alters transcription in the T-cell clone,at a scale comparable to that induced by antibody-mediated ligation of CD3.The character of the resulting changes is distinct,however,with the net effect ofCD8 ligation being substantially inhibitory.We speculate that ligating CD8 induces weak,T-cell receptor (TCR)-mediated inhibitory signals reminiscent of the effects of TCR antagonists.Our results imply that CD8 ligation alone is incapable of activating the T-cell clone because it fails to fully induce NFAT-dependent transcription.

  18. Polymyalgia rheumatica is characterized by pro-inflammatory, senescent CD8+ T cells

    NARCIS (Netherlands)

    Van Der Geest, K.; Abdulahad, W.; Huitema, M.; Kroesen, B.; Rutgers, A.; Brouwer, E.; Boots, A.

    2013-01-01

    Background Polymyalgia rheumatica (PMR) is a frequent, inflammatory rheumatic disease affecting elderly people. Previous studies suggest that T cell mediated immune responses contribute to PMR. However, little is known about CD4+ and CD8+ T cell subsets and their function in PMR. Furthermore, it rem

  19. Effector CD4 and CD8 T Cells and Their Role in the Tumor Microenvironment

    DEFF Research Database (Denmark)

    Hadrup, Sine; Donia, Marco; thor Straten, Per

    2012-01-01

    with colo-rectal cancer (CRC), and also for others solid cancers. These data goes hand in hand with studies of clonality of TIL showing the T cells among TIL are expanded clonally, and also that tumor specific T cells of CD4 as well as CD8 type are enriched at the tumor site. The tumor microenvironment...

  20. Cloning analysis of HBV-specific CD8 T cell receptor gene in patients with acute hepatitis B

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    Ning DING

    2011-05-01

    Full Text Available Objective To investigate the molecular mechanism of T cell receptor(TCR in CD8 T cell-mediated immune response to HBV in patients with acute hepatitis B(AHB.Methods Peripheral blood mononuclear cells(PBMCs were collected from HLA-A2-positive AHB patients.To determine HBsAg183-191 and HBsAg335-343-specific CD8 T cell frequencies,the PBMCs were stained by fluorescence-labeled anti-CD3,anti-CD8 and pentamers,and analyzed by flow cytometry.PBMCs from 6 patients were stimulated with epitopic peptide HBsAg335-343 in vitro for 3 to 4 weeks.HBV-specific CD8 T cells were isolated by magnetic activated cell sorting followed by flow florescence activated cell sorting.The mRNA of sorted cells was extracted after expanding by IL-2,anti-CD3 and anti-CD8.The full-length gene fragments of variable region of TCR α and β chains were gained by 5’-RACE,and then cloned and sequenced(≥50 clones for single chain of each sample.The gene families of TCR α and β chains were identified and the sequence characters of CDR3 were compared.Results Analysis of more than 600 cloned gene sequences of TCR α and β chains showed that the proliferated HBV-specific CD8 T cells from 6 AHB patients presented a predominant expression in TCR α and chains,with 2-4 α chain families and 1-4 chain families in each case.The α2,α14,α15,β3,β13 and 23 families were detected in more than one case.The chain genes were all 13 for all tested clones in one case.For the same α chain or-chain family,CDR3 sequences tended to be identical in one case but different among cases.Conclusions HBV-specific CD8 T cells with antigenic peptide-induced proliferation present predominance in the usage of TCR α and β chains.This property might be one of the important molecular factors influencing anti-HBV immunity.

  1. Bystander suppression of allergic airway inflammation by lung resident memory CD8+ T cells

    Science.gov (United States)

    Marsland, Benjamin J.; Harris, Nicola L.; Camberis, Mali; Kopf, Manfred; Hook, Sarah M.; Le Gros, Graham

    2004-04-01

    CD8+ memory T cells have recently been recognized as playing a key role in natural immunity against unrelated viral infections, a phenomenon referred to as "heterologous antiviral immunity." We now provide data that the cellular immunological interactions that underlie such heterologous immunity can play an equally important role in regulating T helper 2 immune responses and protecting mucosal surfaces from allergen-induced inflammation. Our data show that CD8+ T cells, either retained in the lung after infection with influenza virus, or adoptively transferred via the intranasal route can suppress allergic airway inflammation. The suppression is mediated by IFN-, which acts to reduce the activation level, T helper 2 cytokine production, airways hyperresponsiveness, and migration of allergen-specific CD4+ T cells into the lung, whereas the systemic and draining lymph node responses remain unchanged. Of note, adoptive transfer of previously activated transgenic CD8+ T cells conferred protection against allergic airway inflammation, even in the absence of specific-antigen. Airway resident CD8+ T cells produced IFN- when directly exposed to conditioned media from activated dendritic cells or the proinflammatory cytokines IL-12 and IL-18. Taken together these data indicate that effector/memory CD8+ T cells present in the airways produce IFN- after inflammatory stimuli, independent of specific-antigen, and as a consequence play a key role in modifying the degree and frequency of allergic responses in the lung.

  2. Visualizing early splenic memory CD8+ T cells reactivation against intracellular bacteria in the mouse.

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    Marc Bajénoff

    Full Text Available Memory CD8(+ T cells represent an important effector arm of the immune response in maintaining long-lived protective immunity against viruses and some intracellular bacteria such as Listeria monocytogenes (L.m. Memory CD8(+ T cells are endowed with enhanced antimicrobial effector functions that perfectly tail them to rapidly eradicate invading pathogens. It is largely accepted that these functions are sufficient to explain how memory CD8(+ T cells can mediate rapid protection. However, it is important to point out that such improved functional features would be useless if memory cells were unable to rapidly find the pathogen loaded/infected cells within the infected organ. Growing evidences suggest that the anatomy of secondary lymphoid organs (SLOs fosters the cellular interactions required to initiate naive adaptive immune responses. However, very little is known on how the SLOs structures regulate memory immune responses. Using Listeria monocytogenes (L.m as a murine infection model and imaging techniques, we have investigated if and how the architecture of the spleen plays a role in the reactivation of memory CD8(+ T cells and the subsequent control of L.m growth. We observed that in the mouse, memory CD8(+ T cells start to control L.m burden 6 hours after the challenge infection. At this very early time point, L.m-specific and non-specific memory CD8(+ T cells localize in the splenic red pulp and form clusters around L.m infected cells while naïve CD8(+ T cells remain in the white pulp. Within these clusters that only last few hours, memory CD8(+ T produce inflammatory cytokines such as IFN-gamma and CCL3 nearby infected myeloid cells known to be crucial for L.m killing. Altogether, we describe how memory CD8(+ T cells trafficking properties and the splenic micro-anatomy conjugate to create a spatio-temporal window during which memory CD8(+ T cells provide a local response by secreting effector molecules around infected cells.

  3. Secretion of Interleukin-17 by CD8+ T Cells Expressing CD146 (MCAM)

    OpenAIRE

    Dagur, Pradeep K; Biancotto, Angélique; Stansky, Elena; Sen, H. Nida; Nussenblatt, Robert B.; McCoy, J. Philip

    2014-01-01

    Interleukin-17 (IL-17) has been associated with the pathogenesis of numerous autoimmune diseases. CD4+ T cells secreting IL-17 are termed Th17 cells. CD8+ T cells, designated Tc17 cells, are also capable of secreting IL-17. Here we describe a population of Tc17 cells characterized by the expression of surface CD146, an endothelial adhesion molecule. These cells display signatures of a human Tc17 genotype and phenotype. Circulating CD8+CD146+ T cells are present in low levels in healthy adults...

  4. Spontaneous CD8 T cell responses against the melanocyte differentiation antigen RAB38/NY-MEL-1 in melanoma patients.

    Science.gov (United States)

    Walton, Senta M; Gerlinger, Marco; de la Rosa, Olga; Nuber, Natko; Knights, Ashley; Gati, Asma; Laumer, Monika; Strauss, Laura; Exner, Carolin; Schäfer, Niklaus; Urosevic, Mirjana; Dummer, Reinhard; Tiercy, Jean-Marie; Mackensen, Andreas; Jaeger, Elke; Lévy, Frédéric; Knuth, Alexander; Jäger, Dirk; Zippelius, Alfred

    2006-12-01

    The melanocyte differentiation Ag RAB38/NY-MEL-1 was identified by serological expression cloning (SEREX) and is expressed in the vast majority of melanoma lesions. The immunogenicity of RAB38/NY-MEL-1 has been corroborated previously by the frequent occurrence of specific Ab responses in melanoma patients. To elucidate potential CD8 T cell responses, we applied in vitro sensitization with overlapping peptides spanning the RAB38/NY-MEL-1 protein sequence and the reverse immunology approach. The identified peptide RAB38/NY-MEL-1(50-58) exhibited a marked response in ELISPOT assays after in vitro sensitization of CD8 T cells from HLA-A *0201(+) melanoma patients. In vitro digestion assays using purified proteasomes provided evidence of natural processing of RAB38/NY-MEL-1(50-58) peptide. Accordingly, monoclonal RAB38/NY-MEL-1(50-58)-specific T cell populations were capable of specifically recognizing HLA-A2(+) melanoma cell lines expressing RAB38/NY-MEL-1. Applying fluorescent HLA-A2/RAB38/NY-MEL-1(50-58) multimeric constructs, we were able to document a spontaneously developed memory/effector CD8 T cell response against this peptide in a melanoma patient. To elucidate the Ag-processing pathway, we demonstrate that RAB38/NY-MEL-1(50-58) is produced efficiently by the standard proteasome and the immunoproteasome. In addition to the identification of a RAB38/NY-MEL-1-derived immunogenic CD8 T cell epitope, this study is instrumental for both the onset and monitoring of future RAB38/NY-MEL-1-based vaccination trials. PMID:17114498

  5. High Frequencies of Anti-Host Reactive CD8+ T Cells Ignore Non-Hematopoietic Antigen after Bone Marrow Transplantation in a Murine Model

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    Asmae Gassa

    2016-03-01

    Full Text Available Background: Graft versus host disease (GvHD occurs in 20% of cases with patients having an MHC I matched bone marrow transplantation (BMT. Mechanisms causing this disease remain to be studied. Methods: Here we used a CD8+ T cell transgenic mouse line (P14/CD45.1+ and transgenic DEE mice bearing ubiquitously the glycoprotein 33-41 (GP33 antigen derived from the major lymphocytic choriomeningitis virus (LCMV epitope to study mechanisms of tolerance in anti-host reactive CD8+ T cells after BMT. Results: We found that anti-host reactive CD8+ T cells (P14 T cells were not negatively selected in the thymus and that they were present in wild type (WT recipient mice as well as in DEE recipient mice. Anti-host reactive CD8+ T cells ignored the GP33 antigen expressed ubiquitously by host cells but they could be activated ex vivo via LCMV-infection. Lipopolysaccharides (LPS induced transient cell damage in DEE mice bearing anti-host reactive CD8+ T cells after BMT, suggesting that induction of host inflammatory response could break antigen ignorance. Introducing the GP33 antigen into BM cells led to deletion of anti-host reactive CD8+ T cells. Conclusion: We found that after BMT anti-host reactive CD8+ T cells ignored host antigen in recipients and that they were only deleted when host antigen was present in hematopoietic cells. Moreover, LPS-induced immune activation contributed to induction of alloreactivity of anti-host reactive CD8+ T cells after BMT.

  6. Secretion of interleukin-17 by CD8+ T cells expressing CD146 (MCAM).

    Science.gov (United States)

    Dagur, Pradeep K; Biancotto, Angélique; Stansky, Elena; Sen, H Nida; Nussenblatt, Robert B; McCoy, J Philip

    2014-01-01

    Interleukin-17 (IL-17) has been associated with the pathogenesis of numerous autoimmune diseases. CD4+ T cells secreting IL-17 are termed Th17 cells. CD8+ T cells, designated Tc17 cells, are also capable of secreting IL-17. Here we describe a population of Tc17 cells characterized by the expression of surface CD146, an endothelial adhesion molecule. These cells display signatures of a human Tc17 genotype and phenotype. Circulating CD8+CD146+ T cells are present in low levels in healthy adults. Elevations in CD8+CD146+ T cells are found in Behcet's disease and birdshot retinochoroidopathy, which have been reported to have HLA class I associations. Sarcoidosis does not have a class I association and displays an increase in CD4+ CD146+ T cells but not in CD8+CD146+ T cells. CD146 on these cells may facilitate their ability to bind to, and migrate through, endothelium, as has been reported for CD4+CD146+ T cells. PMID:24681356

  7. Cutting edge: neuronal recognition by CD8 T cells elicits central diabetes insipidus.

    Science.gov (United States)

    Scheikl, Tanja; Pignolet, Béatrice; Dalard, Cécile; Desbois, Sabine; Raison, Danièle; Yamazaki, Masanori; Saoudi, Abdelhadi; Bauer, Jan; Lassmann, Hans; Hardin-Pouzet, Hélène; Liblau, Roland S

    2012-05-15

    An increasing number of neurologic diseases is associated with autoimmunity. The immune effectors contributing to the pathogenesis of such diseases are often unclear. To explore whether self-reactive CD8 T cells could attack CNS neurons in vivo, we generated a mouse model in which the influenza virus hemagglutinin (HA) is expressed specifically in CNS neurons. Transfer of cytotoxic anti-HA CD8 T cells induced an acute but reversible encephalomyelitis in HA-expressing recipient mice. Unexpectedly, diabetes insipidus developed in surviving animals. This robust phenotype was associated with preferential accumulation of cytotoxic CD8 T cells in the hypothalamus, upregulation of MHC class I molecules, and destruction of vasopressin-expressing neurons. IFN-γ production by the pathogenic CD8 T cells was necessary for MHC class I upregulation by hypothalamic neurons and their destruction. This novel mouse model, in combination with related human data, supports the concept that autoreactive CD8 T cells can trigger central diabetes insipidus. PMID:22504649

  8. Memory CD8+ T Cells: Orchestrators and Key Players of Innate Immunity?

    Science.gov (United States)

    Lauvau, Grégoire; Goriely, Stanislas

    2016-09-01

    Over the past decades, the dichotomy between innate and adaptive immune responses has largely dominated our understanding of immunology. Upon primary encounter with microbial pathogens, differentiation of adaptive immune cells into functional effectors usually takes several days or even longer, making them contribute to host protection only late during primary infection. However, once generated, antigen-experienced T lymphocytes can persist in the organism and constitute a pool of memory cells that mediate fast and effective protection to a recall infection with the same microbial pathogen. Herein, we challenge this classical paradigm by highlighting the "innate nature" of memory CD8+ T cells. First, within the thymus or in the periphery, naïve CD8+ T cells may acquire phenotypic and functional characteristics of memory CD8+ T cells independently of challenge with foreign antigens. Second, both the "unconventional" and the "conventional" memory cells can rapidly express protective effector functions in response to sets of inflammatory cytokines and chemokines signals, independent of cognate antigen triggering. Third, memory CD8+ T cells can act by orchestrating the recruitment, activation, and licensing of innate cells, leading to broad antimicrobial states. Thus, collectively, memory CD8+ T cells may represent important actors of innate immune defenses.

  9. Immune hierarchy among HIV-1 CD8+ T cell epitopes delivered by dendritic cells depends on MHC-I binding irrespective of mode of loading and immunization in HLA-A*0201 mice

    DEFF Research Database (Denmark)

    Kloverpris, Henrik N; Karlsson, Ingrid; Thorn, Mette;

    2009-01-01

    , where the immune system responds to only a small number of the epitopes administered. To evaluate the feasibility of such vaccine strategies, we used the human leukocyte antigen (HLA)-A*0201 transgenic (tg) HHD murine in vivo model and immunized with dendritic cells pulsed with seven HIV-1-derived HLA...

  10. Comparison of human memory CD8 T cell responses to adenoviral early and late proteins in peripheral blood and lymphoid tissue.

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    Amita Joshi

    Full Text Available Treatment of invasive adenovirus (Ad disease in hematopoietic stem cell transplant (SCT recipients with capsid protein hexon-specific donor T cells is under investigation. We propose that cytotoxic T cells (CTLs targeted to the late protein hexon may be inefficient in vivo because the early Ad protein E3-19K downregulates HLA class I antigens in infected cells. In this study, CD8+ T cells targeted to highly conserved HLA A2-restricted epitopes from the early regulatory protein DNA polymerase (P-977 and late protein hexon (H-892 were compared in peripheral blood (PB and tonsils of naturally infected adults. In tonsils, epitope-specific pentamers detected a significantly higher frequency of P-977+CD8+ T cells compared to H-892+CD8+ T cells; this trend was reversed in PB. Tonsil epitope-specific CD8+ T cells expressed IFN-γ and IL-2 but not perforin or TNF-α, whereas PB T cells were positive for IFN-γ, TNF-α, and perforin. Tonsil epitope-specific T cells expressed lymphoid homing marker CCR7 and exhibited lower levels of the activation marker CD25 but higher proliferative potential than PB T cells. Finally, in parallel with the kinetics of mRNA expression, P-977-specific CTLs lysed targets as early as 8 hrs post infection. In contrast, H-892-specific CTLs did not kill unless infected fibroblasts were pretreated with IFN-γ to up regulate HLA class I antigens, and cytotoxicity was delayed until 16-24 hours. These data show that, in contrast to hexon CTLs, central memory type DNA polymerase CTLs dominate the lymphoid compartment and kill fibroblasts earlier after infection without requiring exogenous IFN-γ. Thus, use of CTLs targeted to both early and late Ad proteins may improve the efficacy of immunotherapy for life-threatening Ad disease in SCT recipients.

  11. Cutting edge: membrane lymphotoxin regulates CD8(+) T cell-mediated intestinal allograft rejection.

    Science.gov (United States)

    Guo, Z; Wang, J; Meng, L; Wu, Q; Kim, O; Hart, J; He, G; Zhou, P; Thistlethwaite, J R; Alegre, M L; Fu, Y X; Newell, K A

    2001-11-01

    Blocking the CD28/B7 and/or CD154/CD40 costimulatory pathways promotes long-term allograft survival in many transplant models where CD4(+) T cells are necessary for rejection. When CD8(+) T cells are sufficient to mediate rejection, these approaches fail, resulting in costimulation blockade-resistant rejection. To address this problem we examined the role of lymphotoxin-related molecules in CD8(+) T cell-mediated rejection of murine intestinal allografts. Targeting membrane lymphotoxin by means of a fusion protein, mAb, or genetic mutation inhibited rejection of intestinal allografts by CD8(+) T cells. This effect was associated with decreased monokine induced by IFN-gamma (Mig) and secondary lymphoid chemokine (SLC) gene expression within allografts and spleens respectively. Blocking membrane lymphotoxin did not inhibit rejection mediated by CD4(+) T cells. Combining disruption of membrane lymphotoxin and treatment with CTLA4-Ig inhibited rejection in wild-type mice. These data demonstrate that membrane lymphotoxin is an important regulatory molecule for CD8(+) T cells mediating rejection and suggest a strategy to avoid costimulation blockade-resistant rejection. PMID:11673481

  12. The viral context instructs the redundancy of costimulatory pathways in driving CD8(+) T cell expansion.

    Science.gov (United States)

    Welten, Suzanne P M; Redeker, Anke; Franken, Kees L M C; Oduro, Jennifer D; Ossendorp, Ferry; Čičin-Šain, Luka; Melief, Cornelis J M; Aichele, Peter; Arens, Ramon

    2015-01-01

    Signals delivered by costimulatory molecules are implicated in driving T cell expansion. The requirements for these signals, however, vary from dispensable to essential in different infections. We examined the underlying mechanisms of this differential T cell costimulation dependence and found that the viral context determined the dependence on CD28/B7-mediated costimulation for expansion of naive and memory CD8(+) T cells, indicating that the requirement for costimulatory signals is not imprinted. Notably, related to the high-level costimulatory molecule expression induced by lymphocytic choriomeningitis virus (LCMV), CD28/B7-mediated costimulation was dispensable for accumulation of LCMV-specific CD8(+) T cells because of redundancy with the costimulatory pathways induced by TNF receptor family members (i.e., CD27, OX40, and 4-1BB). Type I IFN signaling in viral-specific CD8(+) T cells is slightly redundant with costimulatory signals. These results highlight that pathogen-specific conditions differentially and uniquely dictate the utilization of costimulatory pathways allowing shaping of effector and memory antigen-specific CD8(+) T cell responses. PMID:26263500

  13. Ex vivo SIV-specific CD8 T cell responses in heterozygous animals are primarily directed against peptides presented by a single MHC haplotype.

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    Justin M Greene

    Full Text Available The presence of certain MHC class I alleles is correlated with remarkable control of HIV and SIV, indicating that specific CD8 T cell responses can effectively reduce viral replication. It remains unclear whether epitopic breadth is an important feature of this control. Previous studies have suggested that individuals heterozygous at the MHC class I loci survive longer and/or progress more slowly than those who are homozygous at these loci, perhaps due to increased breadth of the CD8 T cell response. We used Mauritian cynomolgus macaques with defined MHC haplotypes and viral inhibition assays to directly compare CD8 T cell efficacy in MHC-heterozygous and homozygous individuals. Surprisingly, we found that cells from heterozygotes suppress viral replication most effectively on target cells from animals homozygous for only one of two potential haplotypes. The same heterozygous effector cells did not effectively inhibit viral replication as effectively on the target cells homozygous for the other haplotype. These results indicate that the greater potential breadth of CD8 T cell responses present in heterozygous animals does not necessarily lead to greater antiviral efficacy and suggest that SIV-specific CD8 T cell responses in heterozygous animals have a skewed focus toward epitopes restricted by a single haplotype.

  14. Sequence conservation of subdominant HLA-A2-binding CTL epitopes in HIV-1 clinical isolates and CD8+ T-lymphocyte cross-recognition may explain the immune reaction in infected individuals

    DEFF Research Database (Denmark)

    Thorn, Mette; Tang, Sheila; Therrien, Dominic;

    2007-01-01

    genome sequenced HIV-1 from 11 HLA-A2(+) patients to examine the sequence variation of these natural epitopes and compared them with the patient's CD8(+) T-cell recall response. Often the epitope was conserved but only a few patients showed a CD8(+) T-cell recall response. This infrequent targeting may...... be explained by immune subdominance. CD8(+) T-cell recall response to a natural epitope could be measured despite sequence differences in the patient's virus. T-cell cross-reaction between such variants could be demonstrated in HLA-A2 transgenic mice. Nine infrequently targeted but conserved or cross...

  15. Interferon-alpha administration enhances CD8+ T cell activation in HIV infection.

    Directory of Open Access Journals (Sweden)

    Maura Manion

    Full Text Available BACKGROUND: Type I interferons play important roles in innate immune defense. In HIV infection, type I interferons may delay disease progression by inhibiting viral replication while at the same time accelerating disease progression by contributing to chronic immune activation. METHODS: To investigate the effects of type I interferons in HIV-infection, we obtained cryopreserved peripheral blood mononuclear cell samples from 10 subjects who participated in AIDS Clinical Trials Group Study 5192, a trial investigating the activity of systemic administration of IFNα for twelve weeks to patients with untreated HIV infection. Using flow cytometry, we examined changes in cell cycle status and expression of activation antigens by circulating T cells and their maturation subsets before, during and after IFNα treatment. RESULTS: The proportion of CD38+HLA-DR+CD8+ T cells increased from a mean of 11.7% at baseline to 24.1% after twelve weeks of interferon treatment (p = 0.006. These frequencies dropped to an average of 20.1% six weeks after the end of treatment. In contrast to CD8+ T cells, the frequencies of activated CD4+ T cells did not change with administration of type I interferon (mean percentage of CD38+DR+ cells = 2.62% at baseline and 2.17% after 12 weeks of interferon therapy. As plasma HIV levels fell with interferon therapy, this was correlated with a "paradoxical" increase in CD8+ T cell activation (p<0.001. CONCLUSION: Administration of type I interferon increased expression of the activation markers CD38 and HLA DR on CD8+ T cells but not on CD4+ T cells of HIV+ persons. These observations suggest that type I interferons may contribute to the high levels of CD8+ T cell activation that occur during HIV infection.

  16. Manipulating Memory CD8 T Cell Numbers by Timed Enhancement of IL-2 Signals.

    Science.gov (United States)

    Kim, Marie T; Kurup, Samarchith P; Starbeck-Miller, Gabriel R; Harty, John T

    2016-09-01

    As a result of the growing burden of tumors and chronic infections, manipulating CD8 T cell responses for clinical use has become an important goal for immunologists. In this article, we show that dendritic cell (DC) immunization coupled with relatively early (days 1-3) or late (days 4-6) administration of enhanced IL-2 signals increase peak effector CD8 T cell numbers, but only early IL-2 signals enhance memory numbers. IL-2 signals delivered at relatively late time points drive terminal differentiation and marked Bim-mediated contraction and do not increase memory T cell numbers. In contrast, early IL-2 signals induce effector cell metabolic profiles that are more conducive to memory formation. Of note, downregulation of CD80 and CD86 was observed on DCs in vivo following early IL-2 treatment. Mechanistically, early IL-2 treatment enhanced CTLA-4 expression on regulatory T cells, and CTLA-4 blockade alongside IL-2 treatment in vivo prevented the decrease in CD80 and CD86, supporting a cell-extrinsic role for CTLA-4 in downregulating B7 ligand expression on DCs. Finally, DC immunization followed by early IL-2 treatment and anti-CTLA-4 blockade resulted in lower memory CD8 T cell numbers compared with the DC+early IL-2 treatment group. These data suggest that curtailed signaling through the B7-CD28 costimulatory axis during CD8 T cell activation limits terminal differentiation and preserves memory CD8 T cell formation; thus, it should be considered in future T cell-vaccination strategies. PMID:27439516

  17. miR-150 Regulates Differentiation and Cytolytic Effector Function in CD8+ T cells

    OpenAIRE

    Smith, Norah L.; Wissink, Erin M.; Andrew Grimson; Rudd, Brian D.

    2015-01-01

    MicroRNAs regulate most mammalian genes, and they control numerous aspects of immune system development and function. Their precise roles in the CD8+ T cell response, however, remain unclear. In this report, we show that in the absence of the microRNA miR-150, CD8+ T cells fail to undergo robust expansion and differentiation into short-lived terminal effector cells in response to primary infection with Listeria monocytogenes or Vaccinia virus. Notably, even after transitioning into the memory...

  18. Characterization of virus-primed CD8+ T cells with a type 1 cytokine profile

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Stenvang, J P; Marker, O;

    1996-01-01

    . Phenotypically, the main cytokine-producing cell subset is found to be CD8+ cells targeted for homing to inflammatory sites (VLA-4hiL-selectinlo) of which 30-40% were positive by intracellular staining for IFN-gamma. This subset also contains all T cells with a cytotoxic potential as measured by redirected...... demonstrate that systemic virus infection may exert marked perturbation of the CD8+ T cell population resulting in generation of a long-lived subset of primed cells with important effector potential....

  19. Role of CD8^+ T Cells in Murine Experimental Allergic Encephalomyelitis

    Science.gov (United States)

    Jiang, Hong; Zhang, Sheng-Le; Pernis, Benvenuto

    1992-05-01

    The course of experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis, is affected by immunoregulatory T lymphocytes. When animals are immunized with encephalitogenic peptide of myelin basic protein and recover from the first episode of EAE, they become resistant to a second induction of this disease. Animals depleted of CD8^+ T cells by antibody-mediated clearance were used to examine the role of CD8^+ T cells in EAE. These cells were found to be major participants in the resistance to a second induction of EAE but were not essential for spontaneous recovery from the first episode of the disease.

  20. Exhaustion of Activated CD8 T Cells Predicts Disease Progression in Primary HIV-1 Infection.

    Directory of Open Access Journals (Sweden)

    Matthias Hoffmann

    2016-07-01

    Full Text Available The rate at which HIV-1 infected individuals progress to AIDS is highly variable and impacted by T cell immunity. CD8 T cell inhibitory molecules are up-regulated in HIV-1 infection and associate with immune dysfunction. We evaluated participants (n = 122 recruited to the SPARTAC randomised clinical trial to determine whether CD8 T cell exhaustion markers PD-1, Lag-3 and Tim-3 were associated with immune activation and disease progression. Expression of PD-1, Tim-3, Lag-3 and CD38 on CD8 T cells from the closest pre-therapy time-point to seroconversion was measured by flow cytometry, and correlated with surrogate markers of HIV-1 disease (HIV-1 plasma viral load (pVL and CD4 T cell count and the trial endpoint (time to CD4 count <350 cells/μl or initiation of antiretroviral therapy. To explore the functional significance of these markers, co-expression of Eomes, T-bet and CD39 was assessed. Expression of PD-1 on CD8 and CD38 CD8 T cells correlated with pVL and CD4 count at baseline, and predicted time to the trial endpoint. Lag-3 expression was associated with pVL but not CD4 count. For all exhaustion markers, expression of CD38 on CD8 T cells increased the strength of associations. In Cox models, progression to the trial endpoint was most marked for PD-1/CD38 co-expressing cells, with evidence for a stronger effect within 12 weeks from confirmed diagnosis of PHI. The effect of PD-1 and Lag-3 expression on CD8 T cells retained statistical significance in Cox proportional hazards models including antiretroviral therapy and CD4 count, but not pVL as co-variants. Expression of 'exhaustion' or 'immune checkpoint' markers in early HIV-1 infection is associated with clinical progression and is impacted by immune activation and the duration of infection. New markers to identify exhausted T cells and novel interventions to reverse exhaustion may inform the development of novel immunotherapeutic approaches.

  1. T cells and gene regulation: the switching on and turning up of genes after T cell receptor stimulation in CD8 T cells

    Directory of Open Access Journals (Sweden)

    James M Conley

    2016-02-01

    Full Text Available Signaling downstream of the T cell receptor (TCR is directly regulated by the dose and affinity of peptide antigen. The strength of TCR signaling drives a multitude of T cell functions from development to differentiation. CD8 T cells differentiate into a diverse pool of effector and memory cells after activation, a process that is critical for pathogen clearance and is highly regulated by TCR signal strength. T cells rapidly alter their gene expression upon activation. Multiple signaling pathways downstream of the TCR activate transcription factors, which are critical for this process. The dynamics between proximal TCR signaling, transcription factor activation, and CD8 T cell function are discussed here. We propose that Inducible T cell kinase (ITK acts as a rheostat for gene expression. This unique regulation of TCR signaling by ITK provides a possible signaling mechanism for the promotion of a diverse T cell repertoire in response to pathogen.

  2. T Cells and Gene Regulation: The Switching On and Turning Up of Genes after T Cell Receptor Stimulation in CD8 T Cells

    Science.gov (United States)

    Conley, James M.; Gallagher, Michael P.; Berg, Leslie J.

    2016-01-01

    Signaling downstream of the T cell receptor (TCR) is directly regulated by the dose and affinity of peptide antigen. The strength of TCR signaling drives a multitude of T cell functions from development to differentiation. CD8 T cells differentiate into a diverse pool of effector and memory cells after activation, a process that is critical for pathogen clearance and is highly regulated by TCR signal strength. T cells rapidly alter their gene expression upon activation. Multiple signaling pathways downstream of the TCR activate transcription factors, which are critical for this process. The dynamics between proximal TCR signaling, transcription factor activation and CD8 T cell function are discussed here. We propose that inducible T cell kinase (ITK) acts as a rheostat for gene expression. This unique regulation of TCR signaling by ITK provides a possible signaling mechanism for the promotion of a diverse T cell repertoire in response to pathogen. PMID:26973653

  3. CD8+ T cells as a source of IFN-γ production in human cutaneous leishmaniasis.

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    Mahmoud Nateghi Rostami

    Full Text Available BACKGROUND: In human leishmaniasis Th1/Th2 dichotomy similar to murine model is not clearly defined and surrogate marker(s of protection is not yet known. In this study, Th1/Th2 cytokines (IL-5, IL-10, IL-13 and IFN-γ profile induced by purified CD4(+/CD8(+ T cells in response to Leishmania antigens were assessed at transcript and protein levels in 14 volunteers with a history of self-healing cutaneous leishmaniasis (HCL and compared with 18 healthy control volunteers. METHODOLOGY/PRINCIPAL FINDINGS: CD4(+/CD8(+/CD14(+ cells were purified from peripheral blood using magnetic beads; CD4(+/CD8(+ T cells were co-cultured with autologous CD14(+ monocytes in the presence of soluble Leishmania antigens (SLA. Stimulation of either CD4(+ T cells or CD8(+ T cells of HCL volunteers with SLA induced a significantly (P<0.05 higher IFN-γ production compared with the cells of controls. Upregulation of IFN-γ gene expression in CD4(+ cells (P<0.001 and CD8(+ cells (P = 0.006 of HCL volunteers was significantly more than that of controls. Significantly (P<0.05 higher fold-expression of IFN-γ gene was seen in CD4(+ cells than in CD8(+ cells. In HCL volunteers a significantly (P = 0.014 higher number of CD4(+ cells were positive for intracellular IFN-γ production than CD8(+ cells. CONCLUSIONS/SIGNIFICANCE: Collectively, the volunteers have shown maintenance of specific long-term immune responses characterized by a strong reaction to leishmanin skin test and IFN-γ production. The dominant IFN-γ response was the result of expansion of both CD4(+ and CD8(+ T cells. The results suggested that immune response in protected individuals with a history of zoonotic cutaneous leishmaniasis (ZCL due to L. major is mediated not only through the expansion of antigen-specific IFN-γ producing CD4(+ Th1 cells, but also through IFN-γ producing CD8(+ T cells.

  4. Induction of CD8 T-cell responses restricted to multiple HLA class I alleles in a cancer patient by immunization with a 20-mer NY-ESO-1f (NY-ESO-1 91-110) peptide.

    Science.gov (United States)

    Eikawa, Shingo; Kakimi, Kazuhiro; Isobe, Midori; Kuzushima, Kiyotaka; Luescher, Immanuel; Ohue, Yoshihiro; Ikeuchi, Kazuhiro; Uenaka, Akiko; Nishikawa, Hiroyoshi; Udono, Heiichiro; Oka, Mikio; Nakayama, Eiichi

    2013-01-15

    Immunogenicity of a long 20-mer NY-ESO-1f peptide vaccine was evaluated in a lung cancer patient TK-f01, immunized with the peptide with Picibanil OK-432 and Montanide ISA-51. We showed that internalization of the peptide was necessary to present CD8 T-cell epitopes on APC, contrasting with the direct presentation of the short epitope. CD8 T-cell responses restricted to all five HLA class I alleles were induced in the patient after the peptide vaccination. Clonal analysis showed that B*35:01 and B*52:01-restricted CD8 T-cell responses were the two dominant responses. The minimal epitopes recognized by A*24:02, B*35:01, B*52:01 and C*12:02-restricted CD8 T-cell clones were defined and peptide/HLA tetramers were produced. NY-ESO-1 91-101 on A*24:02, NY-ESO-1 92-102 on B*35:01, NY-ESO-1 96-104 on B*52:01 and NY-ESO-1 96-104 on C*12:02 were new epitopes first defined in this study. Identification of the A*24:02 epitope is highly relevant for studying the Japanese population because of its high expression frequency (60%). High affinity CD8 T-cells recognizing tumor cells naturally expressing the epitopes and matched HLA were induced at a significant level. The findings suggest the usefulness of a long 20-mer NY-ESO-1f peptide harboring multiple CD8 T-cell epitopes as an NY-ESO-1 vaccine. Characterization of CD8 T-cell responses in immunomonitoring using peptide/HLA tetramers revealed that multiple CD8 T-cell responses comprised the dominant response.

  5. Efficacious Early Antiviral Activity of HIV Gag- and Pol-Specific HLA-B*2705-Restricted CD8+ T Cells

    OpenAIRE

    Payne, Rebecca P.; Kløverpris, Henrik; Sacha, Jonah B.; Brumme, Zabrina; Brumme, Chanson; Buus, Søren; Sims, Stuart; Hickling, Stephen; Riddell, Lynn; Chen, Fabian; Luzzi, Graz; Edwards, Anne; Phillips, Rodney; Prado, Julia G.; Goulder, Philip J. R.

    2010-01-01

    The association between HLA-B*2705 and the immune control of human immunodeficiency virus type 1 (HIV-1) has previously been linked to the targeting of the HLA-B*2705-restricted Gag epitope KRWIILGLNK (KK10) by CD8+ T cells. In order to better define the mechanisms of the HLA-B*2705 immune control of HIV, we first characterized the CD8+ T-cell responses of nine highly active antiretroviral therapy (HAART)-naïve B*2705-positive subjects. Unexpectedly, we observed a strong response to an HLA-B*...

  6. The Breadth of Expandable Memory CD8+ T Cells Inversely Correlates with Residual Viral Loads in HIV Elite Controllers

    Science.gov (United States)

    Ndhlovu, Zaza M.; Stampouloglou, Eleni; Cesa, Kevin; Mavrothalassitis, Orestes; Alvino, Donna Marie; Li, Jonathan Z.; Wilton, Shannon; Karel, Daniel; Piechocka-Trocha, Alicja; Chen, Huabiao; Pereyra, Florencia

    2015-01-01

    ABSTRACT Previous studies have shown that elite controllers with minimal effector T cell responses harbor a low-frequency, readily expandable, highly functional, and broadly directed memory population. Here, we interrogated the in vivo relevance of this cell population by investigating whether the breadth of expandable memory responses is associated with the magnitude of residual viremia in individuals achieving durable suppression of HIV infection. HIV-specific memory CD8+ T cells were expanded by using autologous epitopic and variant peptides. Viral load was measured by an ultrasensitive single-copy PCR assay. Following expansion, controllers showed a greater increase in the overall breadth of Gag responses than did untreated progressors (P = 0.01) as well as treated progressors (P = 0.0003). Nef- and Env-specific memory cells expanded poorly for all groups, and their expanded breadths were indistinguishable among groups (P = 0.9 for Nef as determined by a Kruskal-Wallis test; P = 0.6 for Env as determined by a Kruskal-Wallis test). More importantly, we show that the breadth of expandable, previously undetectable Gag-specific responses was inversely correlated with residual viral load (r = −0.6; P = 0.009). Together, these data reveal a direct link between the abundance of Gag-specific expandable memory responses and prolonged maintenance of low-level viremia. Our studies highlight a CD8+ T cell feature that would be desirable in a vaccine-induced T cell response. IMPORTANCE Many studies have shown that the rare ability of some individuals to control HIV infection in the absence of antiretroviral therapy appears to be heavily dependent upon special HIV-specific killer T lymphocytes that are able to inhibit viral replication. The identification of key features of these immune cells has the potential to inform rational HIV vaccine design. This study shows that a special subset of killer lymphocytes, known as central memory CD8+ T lymphocytes, is at least

  7. AMPKα1: A glucose sensor that controls CD8 T-cell memory

    OpenAIRE

    Finlay, David

    2013-01-01

    The adenosine monophosphate-activated protein kinase (AMPK) is activated by antigen receptor signals and energy stress in T cells. In many cell types, AMPK can maintain energy homeostasis and can enforce quiescence to limit energy demands. We consequently evaluated the importance of AMPK for controlling the transition of metabolically active effector CD8 T lymphocytes to the metabolically quiescent catabolic memory T cells during the contraction phase of the immune response. We show that AMPK...

  8. Pharmacologic Induction of CD8+ T Cell Memory: Better Living Through Chemistry

    OpenAIRE

    Gattinoni, Luca; Klebanoff, Christopher A.; Restifo, Nicholas P

    2009-01-01

    The generation of a robust population of memory T cells is critical for effective vaccine and cell-based therapies to prevent and treat infectious diseases and cancer. A series of recent papers have established a new, cell-intrinsic approach in which small molecules target key metabolic and developmental pathways to enhance the formation and maintenance of highly functional CD8+ memory T cells. These findings raise the exciting new possibility of using small molecules, many of which are alrea...

  9. HIV-specific CD8+ T cells: serial killers condemned to die?

    Science.gov (United States)

    Petrovas, Constantinos; Mueller, Yvonne M; Katsikis, Peter D

    2004-04-01

    An increasing body of evidence supports a key role for cytotoxic CD8+ T cells (CTL) in controlling HIV infection. Although a vigorous HIV-specific CD8+ T cell response is raised during the primary infection, these cells ultimately fail to control virus and prevent disease progression. The failure of CTL to control HIV infection has been attributed to a number of strategies HIV employs to evade the immune system. Recently, intrinsic defects in the CTL themselves have been proposed to contribute to the failure of CTL to control HIV. HIV-specific CD8+ T cells differ in their effector/memory phenotype from other virus-specific CD8+ T cells indicating that their differentiation status differs. This altered differentiation may affect effector functions as well as homing properties of these cells. Other studies have indicated that activation of HIV-specific CTL may be impaired and this contributes to their dysfunction. The effector function of these CTL may also be affected. There are conflicting reports about their ability to kill, whereas IFNgamma production does not appear to be impaired in these cells. In this review we focus on recent work indicating that apoptosis may be an important mechanism through which HIV evades the CTL response. In particular, HIV-specific CD8+ T cells are highly susceptible to CD95/Fas-induced apoptosis. This leads to the hypothesis that virus-specific cytotoxic T cells can be eliminated upon binding CD95L/FasL on HIV-infected cells. Understanding the intrinsic defects of CTL in HIV infection could lead to new therapeutic strategies and optimized vaccination protocols that enhance the HIV-specific cytotoxic response.

  10. The IL-17A-producing CD8+ T-cell population in psoriatic lesional skin comprises mucosa-associated invariant T cells and conventional T cells.

    Science.gov (United States)

    Teunissen, Marcel B M; Yeremenko, Nataliya G; Baeten, Dominique L P; Chielie, Saskia; Spuls, Phyllis I; de Rie, Menno A; Lantz, Olivier; Res, Pieter C M

    2014-12-01

    IL-17A is pivotal in the etiology of psoriasis, and CD8(+) T cells with the ability to produce this cytokine (Tc17 cells) are over-represented in psoriatic lesions. Here we demonstrate that the frequency of Tc17 cells in peripheral blood of psoriasis patients correlated with the clinical severity of the disease. Analysis of cutaneous-associated lymphocyte antigen expression showed that the blood Tc17 population contains a significantly higher proportion of cells with skin-homing potential compared with the CD8(+) T-cell population lacking IL-17A/IL-22 expression. IL-17A-producing CD8(+) T cells in blood have previously been reported to belong mainly to the mucosa-associated invariant T-cell (MAIT cell) lineage characterized by TCR Vα7.2 chain, CD161, IL-18Rα, and multidrug transporter ABCB1 expression. We demonstrate the presence of CD8(+) MAIT cells in the dermis and epidermis of psoriatic plaques, as well as healthy skin; however, IL-17A-producing CD8(+) MAIT cells were predominantly found in psoriatic skin. Notably, we observed IL-17A production in a large proportion of psoriatic plaque-derived CD8(+) T cells devoid of MAIT cell characteristics, likely representing conventional CD8(+) T cells. In conclusion, we provide supporting evidence that implicates Tc17 cells in the pathogenesis of psoriasis and describe the presence of innate CD8(+) MAIT cells in psoriatic lesions as an alternative source of IL-17A. PMID:24945094

  11. Contrasting roles for CD4 vs. CD8 T-cells in a murine model of virally induced "T1 black hole" formation.

    Science.gov (United States)

    Pirko, Istvan; Chen, Yi; Lohrey, Anne K; McDole, Jeremiah; Gamez, Jeffrey D; Allen, Kathleen S; Pavelko, Kevin D; Lindquist, Diana M; Dunn, R Scott; Macura, Slobodan I; Johnson, Aaron J

    2012-01-01

    MRI is sensitive to tissue pathology in multiple sclerosis (MS); however, most lesional MRI findings have limited correlation with disability. Chronic T1 hypointense lesions or "T1 black holes" (T1BH), observed in a subset of MS patients and thought to represent axonal damage, show moderate to strong correlation with disability. The pathogenesis of T1BH remains unclear. We previously reported the first and as of yet only model of T1BH formation in the Theiler's murine encephalitis virus induced model of acute CNS neuroinflammation induced injury, where CD8 T-cells are critical mediators of axonal damage and related T1BH formation. The purpose of this study was to further analyze the role of CD8 and CD4 T-cells through adoptive transfer experiments and to determine if the relevant CD8 T-cells are classic epitope specific lymphocytes or different subsets. C57BL/6 mice were used as donors and RAG-1 deficient mice as hosts in our adoptive transfer experiments. In vivo 3-dimensional MRI images were acquired using a 7 Tesla small animal MRI system. For image analysis, we used semi-automated methods in Analyze 9.1; transfer efficiency was monitored using FACS of brain infiltrating lymphocytes. Using a peptide depletion method, we demonstrated that the majority of CD8 T-cells are classic epitope specific cytotoxic cells. CD8 T-cell transfer successfully restored the immune system's capability to mediate T1BH formation in animals that lack adaptive immune system, whereas CD4 T-cell transfer results in an attenuated phenotype with significantly less T1BH formation. These findings demonstrate contrasting roles for these cell types, with additional evidence for a direct pathogenic role of CD8 T-cells in our model of T1 black hole formation. PMID:22348089

  12. Contrasting roles for CD4 vs. CD8 T-cells in a murine model of virally induced "T1 black hole" formation.

    Directory of Open Access Journals (Sweden)

    Istvan Pirko

    Full Text Available MRI is sensitive to tissue pathology in multiple sclerosis (MS; however, most lesional MRI findings have limited correlation with disability. Chronic T1 hypointense lesions or "T1 black holes" (T1BH, observed in a subset of MS patients and thought to represent axonal damage, show moderate to strong correlation with disability. The pathogenesis of T1BH remains unclear. We previously reported the first and as of yet only model of T1BH formation in the Theiler's murine encephalitis virus induced model of acute CNS neuroinflammation induced injury, where CD8 T-cells are critical mediators of axonal damage and related T1BH formation. The purpose of this study was to further analyze the role of CD8 and CD4 T-cells through adoptive transfer experiments and to determine if the relevant CD8 T-cells are classic epitope specific lymphocytes or different subsets. C57BL/6 mice were used as donors and RAG-1 deficient mice as hosts in our adoptive transfer experiments. In vivo 3-dimensional MRI images were acquired using a 7 Tesla small animal MRI system. For image analysis, we used semi-automated methods in Analyze 9.1; transfer efficiency was monitored using FACS of brain infiltrating lymphocytes. Using a peptide depletion method, we demonstrated that the majority of CD8 T-cells are classic epitope specific cytotoxic cells. CD8 T-cell transfer successfully restored the immune system's capability to mediate T1BH formation in animals that lack adaptive immune system, whereas CD4 T-cell transfer results in an attenuated phenotype with significantly less T1BH formation. These findings demonstrate contrasting roles for these cell types, with additional evidence for a direct pathogenic role of CD8 T-cells in our model of T1 black hole formation.

  13. The nucleocapsid protein of Rift Valley fever virus is a potent human CD8+ T cell antigen and elicits memory responses.

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    Weidong Xu

    Full Text Available There is no licensed human vaccine currently available for Rift Valley Fever Virus (RVFV, a Category A high priority pathogen and a serious zoonotic threat. While neutralizing antibodies targeting the viral glycoproteins are protective, they appear late in the course of infection, and may not be induced in time to prevent a natural or bioterrorism-induced outbreak. Here we examined the immunogenicity of RVFV nucleocapsid (N protein as a CD8(+ T cell antigen with the potential for inducing rapid protection after vaccination. HLA-A*0201 (A2-restricted epitopic determinants were identified with N-specific CD8(+ T cells from eight healthy donors that were primed with dendritic cells transduced to express N, and subsequently expanded in vitro by weekly re-stimulations with monocytes pulsed with 59 15mer overlapping peptides (OLPs across N. Two immunodominant epitopes, VT9 (VLSEWLPVT, N(121-129 and IL9 (ILDAHSLYL, N165-173, were defined. VT9- and IL9-specific CD8(+ T cells identified by tetramer staining were cytotoxic and polyfunctional, characteristics deemed important for viral control in vivo. These peptides induced specific CD8(+ T cell responses in A2-transgenic mice, and more importantly, potent N-specific CD8(+ T cell reactivities, including VT9- and IL9-specific ones, were mounted by mice after a booster vaccination with the live attenuated RVF MP-12. Our data suggest that the RVFV N protein is a potent human T cell immunogen capable of eliciting broad, immunodominant CD8(+ T cell responses that are potentially protective. Understanding the immune responses to the nucleocapsid is central to the design of an effective RVFV vaccine irrespective of whether this viral protein is effective as a stand-alone immunogen or only in combination with other RVFV antigens.

  14. Tumor necrosis factor alpha production from CD8+ T cells mediates oviduct pathological sequelae following primary genital Chlamydia muridarum infection.

    Science.gov (United States)

    Murthy, Ashlesh K; Li, Weidang; Chaganty, Bharat K R; Kamalakaran, Sangamithra; Guentzel, M Neal; Seshu, J; Forsthuber, Thomas G; Zhong, Guangming; Arulanandam, Bernard P

    2011-07-01

    The immunopathogenesis of Chlamydia trachomatis-induced oviduct pathological sequelae is not well understood. Mice genetically deficient in perforin (perforin(-/-) mice) or tumor necrosis factor alpha (TNF-α) production (TNF-α(-/-) mice) displayed comparable vaginal chlamydial clearance rates but significantly reduced oviduct pathology (hydrosalpinx) compared to that of wild-type mice. Since both perforin and TNF-α are effector mechanisms of CD8(+) T cells, we evaluated the role of CD8(+) T cells during genital Chlamydia muridarum infection and oviduct sequelae. Following vaginal chlamydial challenge, (i) mice deficient in TAP I (and therefore the major histocompatibility complex [MHC] I pathway and CD8(+) T cells), (ii) wild-type mice depleted of CD8(+) T cells, and (iii) mice genetically deficient in CD8 (CD8(-/-) mice) all displayed similar levels of vaginal chlamydial clearance but significantly reduced hydrosalpinx, compared to those of wild-type C57BL/6 mice, suggesting a role for CD8(+) T cells in chlamydial pathogenesis. Repletion of CD8(-/-) mice with wild-type or perforin(-/-), but not TNF-α(-/-), CD8(+) T cells at the time of challenge restored hydrosalpinx to levels observed in wild-type C57BL/6 mice, suggesting that TNF-α production from CD8(+) T cells is important for pathogenesis. Additionally, repletion of TNF-α(-/-) mice with TNF-α(+/+) CD8(+) T cells significantly enhanced the incidence of hydrosalpinx and oviduct dilatation compared to those of TNF-α(-/-) mice but not to the levels found in wild-type mice, suggesting that TNF-α production from CD8(+) T cells and non-CD8(+) cells cooperates to induce optimal oviduct pathology following genital chlamydial infection. These results provide compelling new evidence supporting the contribution of CD8(+) T cells and TNF-α production to Chlamydia-induced reproductive tract sequelae.

  15. Prolonged activation of virus-specific CD8+T cells after acute B19 infection

    DEFF Research Database (Denmark)

    Isa, Adiba; Kasprowicz, Victoria; Norbeck, Oscar;

    2005-01-01

    BACKGROUND: Human parvovirus B19 (B19) is a ubiquitous and clinically significant pathogen, causing erythema infectiosum, arthropathy, transient aplastic crisis, and intrauterine fetal death. The phenotype of CD8+ T cells in acute B19 infection has not been studied previously. METHODS AND FINDINGS...

  16. miR-150 Regulates Differentiation and Cytolytic Effector Function in CD8+ T cells.

    Science.gov (United States)

    Smith, Norah L; Wissink, Erin M; Grimson, Andrew; Rudd, Brian D

    2015-01-01

    MicroRNAs regulate most mammalian genes, and they control numerous aspects of immune system development and function. Their precise roles in the CD8+ T cell response, however, remain unclear. In this report, we show that in the absence of the microRNA miR-150, CD8+ T cells fail to undergo robust expansion and differentiation into short-lived terminal effector cells in response to primary infection with Listeria monocytogenes or Vaccinia virus. Notably, even after transitioning into the memory pool, miR-150(-/-) cells still mount a weaker recall response to secondary infection, and remain less differentiated than their wild-type counterparts. Transcriptome analysis shows miR-150 gene targets are globally upregulated in cells lacking miR-150, and amongst these targets, we found misregulation of genes associated with proliferation and effector cell function. These transcriptome data suggest that miR-150 deficient CD8+ T cells are less efficient in killing infected cells, which we validate experimentally. Together, these results reveal a cell-intrinsic role for miR-150 in the regulation of effector CD8+ T cell fate and function. PMID:26549197

  17. Influence of race on microsatellite instability and CD8+ T cell infiltration in colon cancer.

    Directory of Open Access Journals (Sweden)

    John M Carethers

    Full Text Available African American patients with colorectal cancer show higher mortality than their Caucasian counterparts. Biology might play a partial role, and prior studies suggest a higher prevalence for microsatellite instability (MSI among cancers from African Americans, albeit patients with MSI cancers have improved survival over patients with non-MSI cancers, counter to the outcome observed for African American patients. CD8+ T cell infiltration of colon cancer is postively correlated with MSI tumors, and is also related to improved outcome. Here, we utilized a 503-person, population-based colon cancer cohort comprising 45% African Americans to determine, under blinded conditions from all epidemiological data, the prevalence of MSI and associated CD8+ T cell infiltration within the cancers. Among Caucasian cancers, 14% were MSI, whereas African American cancers demonstrated 7% MSI (P = 0.009. Clinically, MSI cancers between races were similar; among microsatellite stable cancers, African American patients were younger, female, and with proximal cancers. CD8+ T cells were higher in MSI cancers (88.0 vs 30.4/hpf, P<0.0001, but was not different between races. Utilizing this population-based cohort, African American cancers show half the MSI prevalence of Caucasians without change in CD8+ T cell infiltration which may contribute towards their higher mortality from colon cancer.

  18. Direct presentation is sufficient for an efficient anti-viral CD8+ T cell response.

    Directory of Open Access Journals (Sweden)

    Ren-Huan Xu

    2010-02-01

    Full Text Available The extent to which direct- and cross-presentation (DP and CP contribute to the priming of CD8(+ T cell (T(CD8+ responses to viruses is unclear mainly because of the difficulty in separating the two processes. Hence, while CP in the absence of DP has been clearly demonstrated, induction of an anti-viral T(CD8+ response that excludes CP has never been purposely shown. Using vaccinia virus (VACV, which has been used as the vaccine to rid the world of smallpox and is proposed as a vector for many other vaccines, we show that DP is the main mechanism for the priming of an anti-viral T(CD8+ response. These findings provide important insights to our understanding of how one of the most effective anti-viral vaccines induces immunity and should contribute to the development of novel vaccines.

  19. Profound protection against respiratory challenge with a lethal H7N7 influenza A virus by increasing the magnitude of CD8(+) T-cell memory

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Doherty, P C; Branum, K C;

    2000-01-01

    The recall of CD8(+) T-cell memory established by infecting H-2(b) mice with an H1N1 influenza A virus provided a measure of protection against an extremely virulent H7N7 virus. The numbers of CD8(+) effector and memory T cells specific for the shared, immunodominant D(b)NP(366) epitope were...... greatly increased subsequent to the H7N7 challenge, and though lung titers remained as high as those in naive controls for 5 days or more, the virus was cleared more rapidly. Expanding the CD8(+) memory T-cell pool (10%) by sequential priming with two different influenza A viruses (H3N2-->H1N1...

  20. The Qa-1 Dependent CD8+ T Cell Mediated Regulatory Pathway

    Institute of Scientific and Technical Information of China (English)

    Hong Jiang

    2005-01-01

    The immune system has evolved a variety of regulatory mechanisms to ensure the peripheral self-tolerance as well as the optimal capacity to elicit effective anti-infection immunity. At present, there is no satisfactory conceptual framework to explain how the peripheral immunity is regulated at a biological system level, which enables the immune system to perform its essential functions to mount effective immunity to virtually any foreign antigens but avoid harmful immune responses to self. In this regard, during the past few years, an "affinity/avidity model of peripheral T cell regulation" has been proposed and tested, which opens up a new paradigm to understand how the peripheral immunity, to both self and foreign antigens, is regulated. The paradigm is based on the discovery of a subset CD8+ T cells with TCRs which specifically recognize a unique set of self-peptides presented by the MHC class Ib molecule Qa-1 differentially expressed on T cells as a function of the affinity/avidity of T cell activation.These Qa-1 restricted CD8+ T cells represent an example of how the immune system utilizes a unified mechanism to regulate adaptive immunity to both self and foreign antigens. Thus, by selectively down-regulating T cells of intermediate affinity/avidity, to any antigens, the immune system controls the adaptive immunity without the necessity to distinguish self from non-self in the periphery at the level of T cell regulation.

  1. Clonal expansions of CD8+ T cells with IL-10 secreting capacity occur during chronic Mycobacterium tuberculosis infection.

    Directory of Open Access Journals (Sweden)

    Joshua C Cyktor

    Full Text Available The exact role of CD8(+ T cells during Mycobacterium tuberculosis (Mtb infection has been heavily debated, yet it is generally accepted that CD8(+ T cells contribute to protection against Mtb. In this study, however, we show that the Mtb-susceptible CBA/J mouse strain accumulates large numbers of CD8(+ T cells in the lung as infection progresses, and that these cells display a dysfunctional and immunosuppressive phenotype (PD-1(+, Tim-3(+, CD122(+. CD8(+ T cell expansions from the lungs of Mtb-infected CBA/J mice were also capable of secreting the immunosuppressive cytokine interleukin-10 (IL-10, although in vivo CD8(+ T cell depletion did not significantly alter Mtb burden. Further analysis revealed that pulmonary CD8(+ T cells from Mtb-infected CBA/J mice were clonally expanded, preferentially expressing T cell receptor (TcR Vβ chain 8 (8.2, 8.3 or Vβ 14. Although Vβ8(+ CD8(+ T cells were responsible for the majority of IL-10 production, in vivo depletion of Vβ8(+ did not significantly change the outcome of Mtb infection, which we hypothesize was a consequence of their dual IL-10/IFN-γ secreting profiles. Our data demonstrate that IL-10-secreting CD8(+ T cells can arise during chronic Mtb infection, although the significance of this T cell population in tuberculosis pathogenesis remains unclear.

  2. Interleukin-7 Modulates Anti-Tumor CD8+ T Cell Responses via Its Action on Host Cells

    Science.gov (United States)

    Deiser, Katrin; Stoycheva, Diana; Bank, Ute; Blankenstein, Thomas; Schüler, Thomas

    2016-01-01

    The adoptive transfer of antigen-specific CD8+ T cells is a promising approach for the treatment of chronic viral and malignant diseases. In order to improve adoptive T cell therapy (ATT) of cancer, recent strategies aim at the antibody-based blockade of immunosuppressive signaling pathways in CD8+ T cells. Alternatively, adjuvant effects of immunostimulatory cytokines might be exploited to improve therapeutic CD8+ T cell responses. For example, Interleukin-7 (IL-7) is a potent growth, activation and survival factor for CD8+ T cells that can be used to improve virus- and tumor-specific CD8+ T cell responses. Although direct IL-7 effects on CD8+ T cells were studied extensively in numerous models, the contribution of IL-7 receptor-competent (IL-7R+) host cells remained unclear. In the current study we provide evidence that CD8+ T cell-mediated tumor rejection in response to recombinant IL-7 (rIL-7) therapy is strictly dependent on IL-7R+ host cells. On the contrary, CD8+ T cell expansion is independent of host IL-7R expression. If, however, rIL-7 therapy and peptide vaccination are combined, host IL-7R signaling is crucial for CD8+ T cell expansion. Unexpectedly, maximum CD8+ T cell expansion relies mainly on IL-7R signaling in non-hematopoietic host cells, similar to the massive accumulation of dendritic cells and granulocytes. In summary, we provide evidence that IL-7R+ host cells are major targets of rIL-7 that modulate therapeutic CD8+ T cell responses and the outcome of rIL-7-assisted ATT. This knowledge may have important implications for the design and optimization of clinical ATT protocols. PMID:27447484

  3. Interleukin-7 Modulates Anti-Tumor CD8+ T Cell Responses via Its Action on Host Cells.

    Directory of Open Access Journals (Sweden)

    Katrin Deiser

    Full Text Available The adoptive transfer of antigen-specific CD8+ T cells is a promising approach for the treatment of chronic viral and malignant diseases. In order to improve adoptive T cell therapy (ATT of cancer, recent strategies aim at the antibody-based blockade of immunosuppressive signaling pathways in CD8+ T cells. Alternatively, adjuvant effects of immunostimulatory cytokines might be exploited to improve therapeutic CD8+ T cell responses. For example, Interleukin-7 (IL-7 is a potent growth, activation and survival factor for CD8+ T cells that can be used to improve virus- and tumor-specific CD8+ T cell responses. Although direct IL-7 effects on CD8+ T cells were studied extensively in numerous models, the contribution of IL-7 receptor-competent (IL-7R+ host cells remained unclear. In the current study we provide evidence that CD8+ T cell-mediated tumor rejection in response to recombinant IL-7 (rIL-7 therapy is strictly dependent on IL-7R+ host cells. On the contrary, CD8+ T cell expansion is independent of host IL-7R expression. If, however, rIL-7 therapy and peptide vaccination are combined, host IL-7R signaling is crucial for CD8+ T cell expansion. Unexpectedly, maximum CD8+ T cell expansion relies mainly on IL-7R signaling in non-hematopoietic host cells, similar to the massive accumulation of dendritic cells and granulocytes. In summary, we provide evidence that IL-7R+ host cells are major targets of rIL-7 that modulate therapeutic CD8+ T cell responses and the outcome of rIL-7-assisted ATT. This knowledge may have important implications for the design and optimization of clinical ATT protocols.

  4. Interleukin-7 Modulates Anti-Tumor CD8+ T Cell Responses via Its Action on Host Cells.

    Science.gov (United States)

    Deiser, Katrin; Stoycheva, Diana; Bank, Ute; Blankenstein, Thomas; Schüler, Thomas

    2016-01-01

    The adoptive transfer of antigen-specific CD8+ T cells is a promising approach for the treatment of chronic viral and malignant diseases. In order to improve adoptive T cell therapy (ATT) of cancer, recent strategies aim at the antibody-based blockade of immunosuppressive signaling pathways in CD8+ T cells. Alternatively, adjuvant effects of immunostimulatory cytokines might be exploited to improve therapeutic CD8+ T cell responses. For example, Interleukin-7 (IL-7) is a potent growth, activation and survival factor for CD8+ T cells that can be used to improve virus- and tumor-specific CD8+ T cell responses. Although direct IL-7 effects on CD8+ T cells were studied extensively in numerous models, the contribution of IL-7 receptor-competent (IL-7R+) host cells remained unclear. In the current study we provide evidence that CD8+ T cell-mediated tumor rejection in response to recombinant IL-7 (rIL-7) therapy is strictly dependent on IL-7R+ host cells. On the contrary, CD8+ T cell expansion is independent of host IL-7R expression. If, however, rIL-7 therapy and peptide vaccination are combined, host IL-7R signaling is crucial for CD8+ T cell expansion. Unexpectedly, maximum CD8+ T cell expansion relies mainly on IL-7R signaling in non-hematopoietic host cells, similar to the massive accumulation of dendritic cells and granulocytes. In summary, we provide evidence that IL-7R+ host cells are major targets of rIL-7 that modulate therapeutic CD8+ T cell responses and the outcome of rIL-7-assisted ATT. This knowledge may have important implications for the design and optimization of clinical ATT protocols.

  5. 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

    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...... effect of new stimulatory cocktails, e.g. cytokines and co-stimulatory molecules, by use of the present rapid and easy-to-use method of expanding peptide specific T cells.......Development of methods for efficient in vitro stimulation and expansion of peptide specific CD8(+) T cells is compelling not only with respect to adoptive T cell therapy but also regarding analysis of T cell responses and search for new immunogenic peptides. In the present study, a new approach to...

  6. Function, phenotype and development of human CD161+CD8 T cells

    OpenAIRE

    Walker, Lucy Jane; Klenerman, Paul; Barnes, Eleanor

    2012-01-01

    Tc17 cells and the semi-invariant human mucosal associated invariant T (MAIT) cells are important CD8+ tissue-homing cell populations. Both are characterized by high expression of CD161 (++) and type-17 differentiation, yet their origins and relationships remain poorly defined. By transcriptional and functional analyses it is demonstrated that a pool of polyclonal, pre-committed type-17 CD161++CD8αβ+ T cells exists in cord blood, from which a prominent MAIT cell (TCR Vα7.2+/Vβ2 or 13.2) popul...

  7. Induction of cytotoxic CD8+CD56+ T cells from human thymocytes by interleukin-15

    DEFF Research Database (Denmark)

    Thulesen, S; Nissen, Mogens Holst; Ødum, N;

    2001-01-01

    CD8(+) CD56(+) cells isolated from human peripheral blood lymphocytes have been shown recently to represent a population of cytotoxic active T cells. However, it is not known if these cells are intrathymically or extrathymically developed or how these cells are influenced by growth factors...... of thymocytes. The majority of the IL-15-grown CD8(+) CD56(+) cells were CD45R0(+), representing a memory phenotype, and showed high expression of the IL-15R-complex and high numbers of CD69(+) cells. Moreover, cytotoxic activity was confined to this cell population....

  8. Therapeutic polypeptides based on HBV core 18-27 epitope can induce CD8+ CTL-mediated cytotoxicity in HLA-A2+ human PBMCs

    Institute of Scientific and Technical Information of China (English)

    Tong-Dong Shi; Yu-Zhang Wu; Zheng-Cai Jia; Li-Yun Zou; Wei Zhou

    2004-01-01

    AIM: To explore how to improve the immunogenicity of HBcAg CTL epitope based polypeptides and to trigger an HBV-specific HLA I-restricted CD8+ T cell response in vitro.METHODS: A new panel of mimetic therapeutic peptides based on the immunodominant B cell epitope of HBV PreS218-24 region, the CTL epitope of HBcAg18-27 and the universal T helper epitope of tetanus toxoid (TT) 830-843was designed using computerized molecular design method and synthesized by Merrifield's solid-phase peptide synthesis.Their immunological properties of stimulating activation and proliferation of lymphocytes, of inducing TH1 polarization,CD8+ T cell magnification and HBV-specific CD8+ CTL mediated cytotoxicity were investigatedin vitro using HLAA2+ human peripheral blood mononuclear cells (PBMCs) from healthy donors and chronic hepatitis B patients.RESULTS: Results demonstrated that the therapeutic polypeptides based on immunodominant HBcAg18-27 CTL,PreS2 B- and universal TH epitopes could stimulate the activation and proliferation of lymphocytes, induce specifically and effectively CD8+ T cell expansion and vigorous HBVspecific CTL-mediated cytotoxicity in human PBMCs.CONCLUSION: It indicated that the introduction of immunodominant T helper plus B-epitopes with short and flexible linkers could dramatically improve the immunogenicity of short CTL epitopes in vitro.

  9. Human and Mouse CD8+CD25+FOXP3+ Regulatory T Cells at Steady State and during Interleukin-2 Therapy

    OpenAIRE

    Churlaud, Guillaume; Pitoiset, Fabien; Jebbawi, Fadi; Lorenzon, Roberta; Bellier, Bertrand; Rosenzwajg, Michelle; Klatzmann, David

    2015-01-01

    International audience In addition to CD4+ regulatory T cells (Tregs), CD8+ suppressor T cells are emerging as an important subset of regulatory T cells. Diverse populations of CD8+ T cells with suppressive activities have been described. Among them, a small population of CD8+CD25+FOXP3+ T cells is found both in mice and humans. In contrast to thymic-derived CD4+CD25+FOXP3+ Tregs, their origin and their role in the pathophysiology of autoimmune diseases (AIDs) are less understood. We repor...

  10. CD11b expression as a marker to distinguish between recently activated effector CD8(+) T cells and memory cells

    DEFF Research Database (Denmark)

    Christensen, Jeanette Erbo; Ørding Andreasen, Susanne; Christensen, Jan Pravsgaard;

    2001-01-01

    subset. Polyclonal virus-specific effector and memory CD8(+) T cells from lymphocytic choriomeningitis- and vesicular stomatitis virus-infected mice were visualized through staining for intracellular IFN-gamma or binding of MHC-peptide tetramers, and Mac-1 expression was evaluated. Naive T cells and most......CD8(+) T cells in different activation states have been difficult to identify phenotypically. In this study we have investigated whether Mac-1 (CD11b) expression can be used as a criterion to distinguish between recently activated effector cells and memory cells belonging to the CD8(+) T cell...... virus-specific memory CD8(+) T cells express little or no Mac-1 independent of the virus model employed. In contrast, the majority of CD8(+) T cells present during acute infection express a significant level of Mac-1 and, similarly, Mac-1 expression is found on secondary effectors generated in response...

  11. Immune outcomes in the liver: Is CD8 T cell fate determined by the environment?

    Science.gov (United States)

    Wong, Yik Chun; Tay, Szun Szun; McCaughan, Geoffrey W; Bowen, David G; Bertolino, Patrick

    2015-10-01

    The liver is known for its tolerogenic properties. This unique characteristic is associated with persistent infection of the liver by the hepatitis B and C viruses. Improper activation of cellular adaptive immune responses within the liver and immune exhaustion over time both contribute to ineffective cytotoxic T cell responses to liver-expressed antigens in animal models, and likely play a role in incomplete clearance of chronic hepatitis virus infections in humans. However, under some conditions, functional immune responses can be elicited against hepatic antigens, resulting in control of hepatotropic infections. In order to develop improved therapeutics in immune-mediated chronic liver diseases, including viral hepatitis, it is essential to understand how intrahepatic immunity is regulated. This review focuses on CD8 T cell immunity directed towards foreign antigens expressed in the liver, and explores how the liver environment dictates the outcome of intrahepatic CD8 T cell responses. Potential strategies to rescue unresponsive CD8 T cells in the liver are also discussed.

  12. Tc17 CD8+ T cells potentiate Th1-mediated autoimmune diabetes in a mouse model.

    Science.gov (United States)

    Saxena, Amit; Desbois, Sabine; Carrié, Nadège; Lawand, Myriam; Mars, Lennart T; Liblau, Roland S

    2012-09-15

    An increase in IL-17-producing CD8+ T (Tc17) cells has been reported in the peripheral blood of children with recent onset type 1 diabetes (T1D), but their contribution to disease pathogenesis is still unknown. To directly study the pathogenic potential of β cell-specific Tc17 cells, we used an experimental model of T1D based on the expression of the neo-self Ag hemagglutinin (HA) in the β cells of the pancreas. When transferred alone, the IL-17-producing HA-specific CD8+ T cells homed to the pancreatic lymph nodes without causing any pancreatic infiltration or tissue destruction. When transferred together with small numbers of diabetogenic HA-specific CD4+ T cells, a strikingly different phenotype developed. Under these conditions, Tc17 cells sustained disease progression, driving the destruction of β-islet cells, causing hyperglycemia and ultimately death. Disease progression did not correlate with functional or numerical alterations among the HA-specific CD4+ T cells. Rather, the transferred CD8+ T cells accumulated in the pancreatic islets and a considerable fraction converted, under the control of IL-12, to an IFN-γ-producing phenotype. Our data indicate that Tc17 cells are not diabetogenic but can potentiate a Th1-mediated disease. Plasticity of the Tc17 lineage is associated with transition to overt disease in this experimental model of T1D. PMID:22904307

  13. PD-1 expression on dendritic cells suppresses CD8+ T cell function and antitumor immunity

    Science.gov (United States)

    Lim, Tong Seng; Chew, Valerie; Sieow, Je Lin; Goh, Siting; Yeong, Joe Poh-Sheng; Soon, Ai Ling; Ricciardi-Castagnoli, Paola

    2016-01-01

    ABSTRACT Programmed death one (PD-1) is a well-established co-inhibitory regulator that suppresses proliferation and cytokine production of T cells. Despite remarkable progress in delineating the functional roles of PD-1 on T lymphocytes, little is known about the regulatory role of PD-1 expressed on myeloid cells such as dendritic cells (DCs). Here, we show that CD8+ T cells can be more potently activated to secrete IL-2 and IFNγ by PD-1-deficient DCs compared to wild-type DCs. Adoptive transfer of PD-1-deficient DCs demonstrated their superior capabilities in inducing antigen-specific CD8+ T cell proliferation in vivo. In addition, we provide first evidence demonstrating the existence of peripheral blood DCs and CD11c+ tumor-infiltrating myeloid cells that co-express PD-1 in patients with hepatocellular carcinoma (HCC). The existence of PD-1-expressing HCC-infiltrating DCs (HIDCs) was further supported in a mouse model of HCC. Intratumoral transfer of PD-1-deficient DCs rendered recipient mice resistant to the growth of HCC by promoting tumor-infiltrating CD8+ effector T cells to secrete perforin and granzyme B. This novel finding provides a deeper understanding of the role of PD-1 in immune regulation and has significant implications for cancer immunotherapies targeting PD-1. PMID:27141339

  14. Perivascular Arrest of CD8+ T Cells Is a Signature of Experimental Cerebral Malaria.

    Directory of Open Access Journals (Sweden)

    Tovah N Shaw

    Full Text Available There is significant evidence that brain-infiltrating CD8+ T cells play a central role in the development of experimental cerebral malaria (ECM during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the mechanisms through which they mediate their pathogenic activity during malaria infection remain poorly understood. Utilizing intravital two-photon microscopy combined with detailed ex vivo flow cytometric analysis, we show that brain-infiltrating T cells accumulate within the perivascular spaces of brains of mice infected with both ECM-inducing (P. berghei ANKA and non-inducing (P. berghei NK65 infections. However, perivascular T cells displayed an arrested behavior specifically during P. berghei ANKA infection, despite the brain-accumulating CD8+ T cells exhibiting comparable activation phenotypes during both infections. We observed T cells forming long-term cognate interactions with CX3CR1-bearing antigen presenting cells within the brains during P. berghei ANKA infection, but abrogation of this interaction by targeted depletion of the APC cells failed to prevent ECM development. Pathogenic CD8+ T cells were found to colocalize with rare apoptotic cells expressing CD31, a marker of endothelial cells, within the brain during ECM. However, cellular apoptosis was a rare event and did not result in loss of cerebral vasculature or correspond with the extensive disruption to its integrity observed during ECM. In summary, our data show that the arrest of T cells in the perivascular compartments of the brain is a unique signature of ECM-inducing malaria infection and implies an important role for this event in the development of the ECM-syndrome.

  15. Modified tumour antigen-encoding mRNA facilitates the analysis of naturally occurring and vaccine-induced CD4 and CD8 T cells in cancer patients.

    Science.gov (United States)

    Knights, Ashley J; Nuber, Natko; Thomson, Christopher W; de la Rosa, Olga; Jäger, Elke; Tiercy, Jean-Marie; van den Broek, Maries; Pascolo, Steve; Knuth, Alexander; Zippelius, Alfred

    2009-03-01

    The development of effective anti-cancer vaccines requires precise assessment of vaccine-induced immunity. This is often hampered by low ex vivo frequencies of antigen-specific T cells and limited defined epitopes. This study investigates the applicability of modified, in vitro-transcribed mRNA encoding a therapeutically relevant tumour antigen to analyse T cell responses in cancer patients. In this study transfection of antigen presenting cells, by mRNA encoding the tumour antigen NY-ESO-1, was optimised and applied to address spontaneous and vaccine-induced T cell responses in cancer patients. Memory CD8+ T cells from lung cancer patients having detectable humoral immune responses directed towards NY-ESO-1 could be efficiently detected in peripheral blood. Specific T cells utilised a range of different T cell receptors, indicating a polyclonal response. Specific killing of a panel of NY-ESO-1 expressing tumour cell lines indicates recognition restricted to several HLA allelic variants, including a novel HLA-B49 epitope. Using a modified mRNA construct targeting the translated antigen to the secretory pathway, detection of NY-ESO-1-specific CD4+ T cells in patients could be enhanced, which allowed the in-depth characterisation of established T cell clones. Moreover, broad CD8+ and CD4+ T cell responses covering multiple epitopes were detected following mRNA stimulation of patients treated with a recombinant vaccinia/fowlpox NY-ESO-1 vaccine. This approach allows for a precise monitoring of responses to tumour antigens in a setting that addresses the breadth and magnitude of antigen-specific T cell responses, and that is not limited to a particular combination of known epitopes and HLA-restrictions. PMID:18663444

  16. Rapamycin Impairs Antitumor CD8+ T-cell Responses and Vaccine-Induced Tumor Eradication.

    Science.gov (United States)

    Chaoul, Nada; Fayolle, Catherine; Desrues, Belinda; Oberkampf, Marine; Tang, Alexandre; Ladant, Daniel; Leclerc, Claude

    2015-08-15

    The metabolic sensor mTOR broadly regulates cell growth and division in cancer cells, leading to a significant focus on studies of rapamycin and its analogues as candidate anticancer drugs. However, mTOR inhibitors have failed to produce useful clinical efficacy, potentially because mTOR is also critical in T cells implicated in immunosurveillance. Indeed, recent studies using rapamycin have demonstrated the important role of mTOR in differentiation and induction of the CD8+ memory in T-cell responses associated with antitumor properties. In this study, we demonstrate that rapamycin harms antitumor immune responses mediated by T cells in the setting of cancer vaccine therapy. Specifically, we analyzed how rapamycin affects the antitumor efficacy of a human papilloma virus E7 peptide vaccine (CyaA-E7) capable of eradicating tumors in the TC-1 mouse model of cervical cancer. In animals vaccinated with CyaA-E7, rapamycin administration completely abolished recruitment of CD8+ T cells into TC-1 tumors along with the ability of the vaccine to reduce infiltration of T regulatory cells and myeloid-derived suppressor cells. Moreover, rapamycin completely abolished vaccine-induced cytotoxic T-cell responses and therapeutic activity. Taken together, our results demonstrate the powerful effects of mTOR inhibition in abolishing T-cell-mediated antitumor immune responses essential for the therapeutic efficacy of cancer vaccines.

  17. Expansion of quiescent lung adenocarcinoma CD8+ T cells by MUC1-8-mer peptide-T2 cell-β2 microglobulin complexes.

    Science.gov (United States)

    Atzin-Méndez, J A; López-González, J S; Báez, R; Arenas-Del Angel, M C; Montaño, L F; Silva-Adaya, D; Lascurain, R; Gorocica, P

    2016-01-01

    Adoptive immunotherapy requires the isolation of CD8+ T cells specific for tumor-associated antigens, their expansion in vitro and their transfusion to the patient to mediate a therapeutic effect. MUC1 is an important adenocarcinoma antigen immunogenic for T cells. The MUC1-derived SAPDTRPA (MUC1-8-mer) peptide is a potent epitope recognized by CD8+ T cells in murine models. Likewise, the T2 cell line has been used as an antigen-presenting cell to activate CD8+ T cells, but so far MUC1 has not been assessed in this context. We evaluated whether the MUC1-8-mer peptide can be presented by T2 cells to expand CD25+CD8+ T cells isolated from HLA-A2+ lung adenocarcinoma patients with stage III or IV tumors. The results showed that MUC1-8-mer peptide-loaded T2 cells activated CD8+ T cells from cancer HLA-A2+ patients when anti-CD2, anti-CD28 antibodies and IL-2 were added. The percentage of CD25+CD8+ T cells was 3-fold higher than those in the non-stimulated cells (P=0.018). HLA-A2+ patient cells showed a significant difference (2.3-fold higher) in activation status than HLA-A2+ healthy control cells (P=0.04). Moreover, 77.6% of MUC1-8-mer peptide-specific CD8+ T cells proliferated following a second stimulation with MUC1-8-mer peptide-loaded T2 cells after 10 days of cell culture. There were significant differences in the percentage of basal CD25+CD8+ T cells in relation to the cancer stage; this difference disappeared after MUC1-8-mer peptide stimulation. In conclusion, expansion of CD25+CD8+ T cells by MUC1-8 peptide-loaded T2 cells plus costimulatory signals via CD2, CD28 and IL-2 can be useful in adoptive immunotherapy.

  18. Neuroantigen-specific autoregulatory CD8+ T cells inhibit autoimmune demyelination through modulation of dendritic cell function.

    Directory of Open Access Journals (Sweden)

    Venkatesh P Kashi

    Full Text Available Experimental autoimmune encephalomyelitis (EAE is a well-established murine model of multiple sclerosis, an immune-mediated demyelinating disorder of the central nervous system (CNS. We have previously shown that CNS-specific CD8+ T cells (CNS-CD8+ ameliorate EAE, at least in part through modulation of CNS-specific CD4+ T cell responses. In this study, we show that CNS-CD8+ also modulate the function of CD11c+ dendritic cells (DC, but not other APCs such as CD11b+ monocytes or B220+ B cells. DC from mice receiving either myelin oligodendrocyte glycoprotein-specific CD8+ (MOG-CD8+ or proteolipid protein-specific CD8+ (PLP-CD8+ T cells were rendered inefficient in priming T cell responses from naïve CD4+ T cells (OT-II or supporting recall responses from CNS-specific CD4+ T cells. CNS-CD8+ did not alter DC subset distribution or MHC class II and CD86 expression, suggesting that DC maturation was not affected. However, the cytokine profile of DC from CNS-CD8+ recipients showed lower IL-12 and higher IL-10 production. These functions were not modulated in the absence of immunization with CD8-cognate antigen, suggesting an antigen-specific mechanism likely requiring CNS-CD8-DC interaction. Interestingly, blockade of IL-10 in vitro rescued CD4+ proliferation and in vivo expression of IL-10 was necessary for the suppression of EAE by MOG-CD8+. These studies demonstrate a complex interplay between CNS-specific CD8+ T cells, DC and pathogenic CD4+ T cells, with important implications for therapeutic interventions in this disease.

  19. Impact of HIV on CD8+ T cell CD57 expression is distinct from that of CMV and aging.

    Directory of Open Access Journals (Sweden)

    Sulggi A Lee

    Full Text Available Chronic antigenic stimulation by cytomegalovirus (CMV is thought to increase "immunosenesence" of aging, characterized by accumulation of terminally differentiated CD28- CD8+ T cells and increased CD57, a marker of proliferative history. Whether chronic HIV infection causes similar effects is currently unclear.We compared markers of CD8+ T cell differentiation (e.g., CD28, CD27, CCR7, CD45RA and CD57 expression on CD28- CD8+ T cells in healthy HIV-uninfected adults with and without CMV infection and in both untreated and antiretroviral therapy (ART-suppressed HIV-infected adults with asymptomatic CMV infection.Compared to HIV-uninfected adults without CMV (n=12, those with asymptomatic CMV infection (n=31 had a higher proportion of CD28-CD8+ T cells expressing CD57 (P=0.005. Older age was also associated with greater proportions of CD28-CD8+ T cells expressing CD57 (rho: 0.47, P=0.007. In contrast, untreated HIV-infected CMV+ participants (n=55 had much lower proportions of CD28- CD8+ cells expressing CD57 than HIV-uninfected CMV+ participants (P<0.0001 and were enriched for less well-differentiated CD28- transitional memory (TTR CD8+ T cells (P<0.0001. Chronically HIV-infected adults maintaining ART-mediated viral suppression (n=96 had higher proportions of CD28-CD8+ T cells expressing CD57 than untreated patients (P<0.0001, but continued to have significantly lower levels than HIV-uninfected controls (P=0.001. Among 45 HIV-infected individuals initiating their first ART regimen, the proportion of CD28-CD8+ T cells expressing CD57 declined (P<0.0001, which correlated with a decline in percent of transitional memory CD8+ T cells, and appeared to be largely explained by a decline in CD28-CD57- CD8+ T cell counts rather than an expansion of CD28-CD57+ CD8+ T cell counts.Unlike CMV and aging, which are associated with terminal differentiation and proliferation of effector memory CD8+ T cells, HIV inhibits this process, expanding less well

  20. Regulation of A1 by OX40 contributes to CD8(+ T cell survival and anti-tumor activity.

    Directory of Open Access Journals (Sweden)

    Fengyang Lei

    Full Text Available The TNFR family member OX40 (CD134 is critical for optimal clonal expansion and survival of T cells. However, the intracellular targets of OX40 in CD8 T cells are not fully understood. Here we show that A1, a Bcl-2 family protein, is regulated by OX40 in effector CD8 T cells. In contrast to wild-type T cells, OX40-deficient CD8 T cells failed to maintain A1 expression driven by antigen. Conversely, enforced OX40 stimulation promoted A1 expression. In both situations, the expression of A1 directly correlated with CD8 T cell survival. In addition, exogenous expression of A1 in OX40-deficient CD8 T cells reversed their survival defect in vitro and in vivo. Moreover, forced expression of A1 in CD8 T cells from OX40-deficient mice restored the ability of these T cells to suppress tumor growth in a murine model. These results indicate that OX40 signals regulate CD8 T cell survival at least in part through maintaining expression of the anti-apoptotic molecule A1, and provide new insight into the mechanism by which OX40 may impact anti-tumor immunity.

  1. STAT3 Regulates Proliferation and Survival of CD8+ T Cells: Enhances Effector Responses to HSV-1 Infection, and Inhibits IL-10+ Regulatory CD8+ T Cells in Autoimmune Uveitis

    OpenAIRE

    Cheng-Rong Yu; Dambuza, Ivy M.; Yong-Jun Lee; Frank, Gregory M.; Egwuagu, Charles E.

    2013-01-01

    STAT3 regulates CD4+ T cell survival and differentiation. However, its effects on CD8+ T cells are not well understood. Here, we show that in comparison to WT CD8+ T cells, STAT3-deficient CD8+ T cells exhibit a preactivated memory-like phenotype, produce more IL-2, proliferate faster, and are more sensitive to activation-induced cell death (AICD). The enhanced proliferation and sensitivity to AICD correlated with downregulation of class-O forkhead transcription factors (FoxO1, FoxO3A), p21wa...

  2. CD4 on CD8+ T cells directly enhances effector function and is a target for HIV infection

    Science.gov (United States)

    Kitchen, Scott G.; Jones, Nicole R.; Laforge, Stuart; Whitmire, Jason K.; Vu, Bien-Aimee; Galic, Zoran; Brooks, David G.; Brown, Stephen J.; Kitchen, Christina M. R.; Zack, Jerome A.

    2004-06-01

    Costimulation of purified CD8+ T lymphocytes induces de novo expression of CD4, suggesting a previously unrecognized function for this molecule in the immune response. Here, we report that the CD4 molecule plays a direct role in CD8+ T cell function by modulating expression of IFN- and Fas ligand, two important CD8+ T cell effector molecules. CD4 expression also allows infection of CD8 cells by HIV, which results in down-regulation of the CD4 molecule and impairs the induction of IFN-, Fas ligand, and the cytotoxic responses of activated CD8+ T cells. Thus, the CD4 molecule plays a direct role in CD8 T cell function, and infection of these cells by HIV provides an additional reservoir for the virus and also may contribute to the immunodeficiency seen in HIV disease.

  3. Targeting Transcriptional Regulators of CD8+ T Cell Dysfunction to Boost Anti-Tumor Immunity.

    Science.gov (United States)

    Waugh, Katherine A; Leach, Sonia M; Slansky, Jill E

    2015-01-01

    Transcription is a dynamic process influenced by the cellular environment: healthy, transformed, and otherwise. Genome-wide mRNA expression profiles reflect the collective impact of pathways modulating cell function under different conditions. In this review we focus on the transcriptional pathways that control tumor infiltrating CD8+ T cell (TIL) function. Simultaneous restraint of overlapping inhibitory pathways may confer TIL resistance to multiple mechanisms of suppression traditionally referred to as exhaustion, tolerance, or anergy. Although decades of work have laid a solid foundation of altered transcriptional networks underlying various subsets of hypofunctional or "dysfunctional" CD8+ T cells, an understanding of the relevance in TIL has just begun. With recent technological advances, it is now feasible to further elucidate and utilize these pathways in immunotherapy platforms that seek to increase TIL function.

  4. Targeting Transcriptional Regulators of CD8+ T Cell Dysfunction to Boost Anti-Tumor Immunity

    Directory of Open Access Journals (Sweden)

    Katherine A. Waugh

    2015-09-01

    Full Text Available Transcription is a dynamic process influenced by the cellular environment: healthy, transformed, and otherwise. Genome-wide mRNA expression profiles reflect the collective impact of pathways modulating cell function under different conditions. In this review we focus on the transcriptional pathways that control tumor infiltrating CD8+ T cell (TIL function. Simultaneous restraint of overlapping inhibitory pathways may confer TIL resistance to multiple mechanisms of suppression traditionally referred to as exhaustion, tolerance, or anergy. Although decades of work have laid a solid foundation of altered transcriptional networks underlying various subsets of hypofunctional or “dysfunctional” CD8+ T cells, an understanding of the relevance in TIL has just begun. With recent technological advances, it is now feasible to further elucidate and utilize these pathways in immunotherapy platforms that seek to increase TIL function.

  5. TGF-β and IL-21 cooperatively stimulate activated CD8(+) T cells to differentiate into Tc17 cells.

    Science.gov (United States)

    Chen, Hsin-Wei; Tsai, Jy-Ping; Yao, Tsung-You; Hsieh, Chia-Ling; Chen, I-Hua; Liu, Shin-Jen

    2016-06-01

    TGF-β together with IL-21 or IL-6 can drive the differentiation of naïve CD8(+) T cells into IL-17-producing CD8(+) T cells. These IL-17-producing CD8(+) T cells are termed Tc17 cells. Tc17 cells preserve plasticity under various conditions in vitro and in vivo. IFN-γ-producing CD8(+) T cells are termed Tc1 cells. However, Tc1 cells are considered relatively stable. In the present study, we show that the combination of TGF-β plus IL-21, but not IL-6, converts Tc1 cells into Tc17 cells; this conversion is associated with elevated RORα, RORγt, and Batf mRNA levels. These results indicate that Tc1 cells are skewed to the Tc17 cell phenotype under TGF-β plus IL-21-polarizing conditions. Furthermore, IL-6R is expressed on naïve, but not activated, CD8(+) T cells. In contrast, IL-21R is expressed on both naïve and activated CD8(+) T cells. Thus, differential expression profiles of IL-6R and IL-21R on naïve and activated CD8(+) T cells may be one mechanism by which TGF-β plus IL-21, but not IL-6, can drive activated CD8(+) T cells to differentiate into IL-17-producing cells. Taken together, these results provide a novel viewpoint for the plasticity of Tc1 cells. PMID:27085379

  6. Blocking of PDL-1 interaction enhances primary and secondary CD8 T cell response to herpes simplex virus-1 infection.

    Directory of Open Access Journals (Sweden)

    Rudragouda Channappanavar

    Full Text Available The blocking of programmed death ligand-1 (PDL-1 has been shown to enhance virus-specific CD8 T cell function during chronic viral infections. Though, how PDL-1 blocking at the time of priming affects the quality of CD8 T cell response to acute infections is not well understood and remains controversial. This report demonstrates that the magnitude of the primary and secondary CD8 T cell responses to herpes simplex virus-1 (HSV-1 infection is subject to control by PDL-1. Our results showed that after footpad HSV-1 infection, PD-1 expression increases on immunodominant SSIEFARL peptide specific CD8 T cells. Additionally, post-infection, the level of PDL-1 expression also increases on CD11c+ dendritic cells. Intraperitoneal administration of anti-PDL-1 monoclonal antibody given one day prior to and three days after cutaneous HSV-1 infection, resulted in a marked increase in effector and memory CD8 T cell response to SSIEFARL peptide. This was shown by measuring the quantity and quality of SSIEFARL-specific CD8 T cells by making use of ex-vivo assays that determine antigen specific CD8 T cell function, such as intracellular cytokine assay, degranulation assay to measure cytotoxicity and viral clearance. Our results are discussed in terms of the beneficial effects of blocking PDL-1 interactions, while giving prophylactic vaccines, to generate a more effective CD8 T cell response to viral infection.

  7. Naive CD8 T-Cells Initiate Spontaneous Autoimmunity to a Sequestered Model Antigen of the Central Nervous System

    Science.gov (United States)

    Na, Shin-Young; Cao, Yi; Toben, Catherine; Nitschke, Lars; Stadelmann, Christine; Gold, Ralf; Schimpl, Anneliese; Hunig, Thomas

    2008-01-01

    In multiple sclerosis, CD8 T-cells are thought play a key pathogenetic role, but mechanistic evidence from rodent models is limited. Here, we have tested the encephalitogenic potential of CD8 T-cells specific for the model antigen ovalbumin (OVA) sequestered in oligodendrocytes as a cytosolic molecule. We show that in these "ODC-OVA" mice, the…

  8. Comparison of Vaccine-Induced Effector CD8 T Cell Responses Directed against Self- and Non-Self-Tumor Antigens

    DEFF Research Database (Denmark)

    Pedersen, Sara R; Sørensen, Maria R; Buus, Søren;

    2013-01-01

    It is generally accepted that CD8 T cells play a major role in tumor control, yet vaccination aimed at eliciting potent CD8 T cell responses are rarely efficient in clinical trials. To try and understand why this is so, we have generated potent adenoviral vectors encoding the endogenous tumor Ags...

  9. CD4+ and CD8+ T cell activation are associated with HIV DNA in resting CD4+ T cells.

    Directory of Open Access Journals (Sweden)

    Leslie R Cockerham

    Full Text Available The association between the host immune environment and the size of the HIV reservoir during effective antiretroviral therapy is not clear. Progress has also been limited by the lack of a well-accepted assay for quantifying HIV during therapy. We examined the association between multiple measurements of HIV and T cell activation (as defined by markers including CD38, HLA-DR, CCR5 and PD-1 in 30 antiretroviral-treated HIV-infected adults. We found a consistent association between the frequency of CD4+ and CD8+ T cells expressing HLA-DR and the frequency of resting CD4+ T cells containing HIV DNA. This study highlights the need to further examine this relationship and to better characterize the biology of markers commonly used in HIV studies. These results may also have implications for reactivation strategies.

  10. PD-1 expression on dendritic cells suppresses CD8+ T cell function and antitumor immunity

    OpenAIRE

    Lim, Tong Seng; Chew, Valerie; Sieow, Je Lin; Goh, Siting; Yeong, Joe Poh-Sheng; Soon, Ai Ling; Ricciardi-Castagnoli, Paola

    2015-01-01

    Programmed death one (PD-1) is a well-established co-inhibitory regulator that suppresses proliferation and cytokine production of T cells. Despite remarkable progress in delineating the functional roles of PD-1 on T lymphocytes, little is known about the regulatory role of PD-1 expressed on myeloid cells such as dendritic cells (DCs). Here, we show that CD8+ T cells can be more potently activated to secrete IL-2 and IFNγ by PD-1-deficient DCs compared to wild-type DCs. Adoptive transfer of P...

  11. TCR Down-Regulation Controls Virus-Specific CD8+ T Cell Responses

    DEFF Research Database (Denmark)

    Bonefeld, Charlotte Menné; Haks, Mariëlle; Nielsen, Bodil;

    2008-01-01

    The CD3gamma di-leucine-based motif plays a central role in TCR down-regulation. However, little is understood about the role of the CD3gamma di-leucine-based motif in physiological T cell responses. In this study, we show that the expansion in numbers of virus-specific CD8(+) T cells is impaired...... in mice with a mutated CD3gamma di-leucine-based motif. The CD3gamma mutation did not impair early TCR signaling, nor did it compromise recruitment or proliferation of virus-specific T cells, but it increased the apoptosis rate of the activated T cells by increasing down-regulation of the...... antiapoptotic molecule Bcl-2. This resulted in a 2-fold reduction in the clonal expansion of virus-specific CD8(+) T cells during the acute phase of vesicular stomatitis virus and lymphocytic choriomeningitis virus infections. These results identify an important role of CD3gamma-mediated TCR down-regulation in...

  12. TCR down-regulation controls virus-specific CD8+ T cell responses

    DEFF Research Database (Denmark)

    Bonefeld, Charlotte Menné; Haks, Mariëlle; Nielsen, Bodil;

    2008-01-01

    The CD3gamma di-leucine-based motif plays a central role in TCR down-regulation. However, little is understood about the role of the CD3gamma di-leucine-based motif in physiological T cell responses. In this study, we show that the expansion in numbers of virus-specific CD8(+) T cells is impaired...... in mice with a mutated CD3gamma di-leucine-based motif. The CD3gamma mutation did not impair early TCR signaling, nor did it compromise recruitment or proliferation of virus-specific T cells, but it increased the apoptosis rate of the activated T cells by increasing down-regulation of the...... antiapoptotic molecule Bcl-2. This resulted in a 2-fold reduction in the clonal expansion of virus-specific CD8(+) T cells during the acute phase of vesicular stomatitis virus and lymphocytic choriomeningitis virus infections. These results identify an important role of CD3gamma-mediated TCR down-regulation in...

  13. Activated iNKT cells promote memory CD8+ T cell differentiation during viral infection.

    Directory of Open Access Journals (Sweden)

    Emma C Reilly

    Full Text Available α-Galactosylceramide (α-GalCer is the prototypical lipid ligand for invariant NKT cells. Recent studies have proposed that α-GalCer is an effective adjuvant in vaccination against a range of immune challenges, however its mechanism of action has not been completely elucidated. A variety of delivery methods have been examined including pulsing dendritic cells with α-GalCer to optimize the potential of α-GalCer. These methods are currently being used in a variety of clinical trials in patients with advanced cancer but cannot be used in the context of vaccine development against pathogens due to their complexity. Using a simple delivery method, we evaluated α-GalCer adjuvant properties, using the mouse model for cytomegalovirus (MCMV. We measured several key parameters of the immune response to MCMV, including inflammation, effector, and central memory CD8(+ T cell responses. We found that α-GalCer injection at the time of the infection decreases viral titers, alters the kinetics of the inflammatory response, and promotes both increased frequencies and numbers of virus-specific memory CD8(+ T cells. Overall, our data suggest that iNKT cell activation by α-GalCer promotes the development of long-term protective immunity through increased fitness of central memory CD8(+ T cells, as a consequence of reduced inflammation.

  14. Human purified CD8+ T cells: Ex vivo expansion model to generate a maximum yield of functional cytotoxic cells.

    Science.gov (United States)

    Al-Shanti, Nasser; Aldahoudi, Ziyad

    2007-01-01

    CD8+ T cells are a critical component of the cellular immune response. They play an important role in the control of viral infection and eliminating cells with malignant potential. However, attempts to generate and expand human CD8+ T cells in vitro for an adoptive immunotherapy have been conducted with limitation of the very low frequency of CD8+ T cells in blood. Therefore, several expansion protocols have been developed to obtain large and efficient numbers of human CD8+ T cells for use in adoptive immunotherapies. In this study various common culture conditions using different cytokines IL-2, IL-4, IL-7, IL-10, IL-12 and IL-15 and autologous feeders and sera were investigated to expand human purified CD8+ T cells. The importance and the influence of these factors on the growth and phenotype of CD8+ T cell were assessed by serially sampling cultures using flow cytometry. We demonstrated that combination of IL-2 (50 U/ml) and autologous feeders induced maximal CD8+ T cell proliferation (40-50 folds) compared to other cytokines. Immunophenotypic analysis of cultured cells showed that expanded CD8+ T cells were activated and differentiated. Furthermore our expansion model also demonstrated that expanded CD8+ T cells are functionally cytotoxic active by killing Allogeneic LCLs cells. In conclusion, we have developed a reliable, simple method that uses minimal cell numbers to generate a high yield of functional cytotoxic CD8+ T cells, which can be used for the development of cellular immunotherapies. PMID:17190652

  15. Osteoclast activated FoxP3+ CD8+ T-cells suppress bone resorption in vitro.

    Directory of Open Access Journals (Sweden)

    Zachary S Buchwald

    Full Text Available BACKGROUND: Osteoclasts are the body's sole bone resorbing cells. Cytokines produced by pro-inflammatory effector T-cells (T(EFF increase bone resorption by osteoclasts. Prolonged exposure to the T(EFF produced cytokines leads to bone erosion diseases such as osteoporosis and rheumatoid arthritis. The crosstalk between T-cells and osteoclasts has been termed osteoimmunology. We have previously shown that under non-inflammatory conditions, murine osteoclasts can recruit naïve CD8 T-cells and activate these T-cells to induce CD25 and FoxP3 (Tc(REG. The activation of CD8 T-cells by osteoclasts also induced the cytokines IL-2, IL-6, IL-10 and IFN-γ. Individually, these cytokines can activate or suppress osteoclast resorption. PRINCIPAL FINDINGS: To determine the net effect of Tc(REG on osteoclast activity we used a number of in vitro assays. We found that Tc(REG can potently and directly suppress bone resorption by osteoclasts. Tc(REG could suppress osteoclast differentiation and resorption by mature osteoclasts, but did not affect their survival. Additionally, we showed that Tc(REG suppress cytoskeletal reorganization in mature osteoclasts. Whereas induction of Tc(REG by osteoclasts is antigen-dependent, suppression of osteoclasts by Tc(REG does not require antigen or re-stimulation. We demonstrated that antibody blockade of IL-6, IL-10 or IFN-γ relieved suppression. The suppression did not require direct contact between the Tc(REG and osteoclasts. SIGNIFICANCE: We have determined that osteoclast-induced Tc(REG can suppress osteoclast activity, forming a negative feedback system. As the CD8 T-cells are activated in the absence of inflammatory signals, these observations suggest that this regulatory loop may play a role in regulating skeletal homeostasis. Our results provide the first documentation of suppression of osteoclast activity by CD8 regulatory T-cells and thus, extend the purview of osteoimmunology.

  16. Characterization of Diabetogenic CD8+ T Cells: IMMUNE THERAPY WITH METABOLIC BLOCKADE.

    Science.gov (United States)

    Garyu, Justin W; Uduman, Mohamed; Stewart, Alex; Rui, Jinxiu; Deng, Songyan; Shenson, Jared; Staron, Matt M; Kaech, Susan M; Kleinstein, Steven H; Herold, Kevan C

    2016-05-20

    Type 1 diabetes mellitus is caused by the killing of insulin-producing β cells by CD8+T cells. The disease progression, which is chronic, does not follow a course like responses to conventional antigens such as viruses, but accelerates as glucose tolerance deteriorates. To identify the unique features of the autoimmune effectors that may explain this behavior, we analyzed diabetogenic CD8+ T cells that recognize a peptide from the diabetes antigen IGRP (NRP-V7-reactive) in prediabetic NOD mice and compared them to others that shared their phenotype (CD44(+)CD62L(lo)PD-1(+)CXCR3(+)) but negative for diabetes antigen tetramers and to LCMV (lymphocytic choriomeningitis)-reactive CD8+ T cells. There was an increase in the frequency of the NRP-V7-reactive cells coinciding with the time of glucose intolerance. The T cells persisted in hyperglycemic NOD mice maintained with an insulin pellet despite destruction of β cells. We compared gene expression in the three groups of cells compared with the other two subsets of cells, and the NRP-V7-reactive cells exhibited gene expression of memory precursor effector cells. They had reduced cellular proliferation and were less dependent on oxidative phosphorylation. When prediabetic NOD mice were treated with 2-deoxyglucose to block aerobic glycolysis, there was a reduction in the diabetes antigen versus other cells of similar phenotype and loss of lymphoid cells infiltrating the islets. In addition, treatment of NOD mice with 2-deoxyglucose resulted in improved β cell granularity. These findings identify a link between metabolic disturbances and autoreactive T cells that promotes development of autoimmune diabetes. PMID:26994137

  17. Acellular pertussis booster in adolescents induces Th1 and memory CD8+ T cell immune response.

    Directory of Open Access Journals (Sweden)

    Nikolaus Rieber

    Full Text Available In a number of countries, whole cell pertussis vaccines (wcP were replaced by acellular vaccines (aP due to an improved reactogenicity profile. Pertussis immunization leads to specific antibody production with the help of CD4(+ T cells. In earlier studies in infants and young children, wcP vaccines selectively induced a Th1 dominated immune response, whereas aP vaccines led to a Th2 biased response. To obtain data on Th1 or Th2 dominance of the immune response in adolescents receiving an aP booster immunization after a wcP or aP primary immunization, we analyzed the concentration of Th1 (IL-2, TNF-α, INF-γ and Th2 (IL-4, IL-5, IL-10 cytokines in supernatants of lymphocyte cultures specifically stimulated with pertussis antigens. We also investigated the presence of cytotoxic T cell responses against the facultative intracellular bacterium Bordetella pertussis by quantifying pertussis-specific CD8(+ T cell activation following the aP booster immunization. Here we show that the adolescent aP booster vaccination predominantly leads to a Th1 immune response based on IFNgamma secretion upon stimulation with pertussis antigen, irrespective of a prior whole cell or acellular primary vaccination. The vaccination also induces an increase in peripheral CD8(+CD69(+ activated pertussis-specific memory T cells four weeks after vaccination. The Th1 bias of this immune response could play a role for the decreased local reactogenicity of this adolescent aP booster immunization when compared to the preceding childhood acellular pertussis booster. Pertussis-specific CD8(+ memory T cells may contribute to protection against clinical pertussis.

  18. Airway CD8(+) T Cells Are Associated with Lung Injury during Infant Viral Respiratory Tract Infection.

    Science.gov (United States)

    Connors, Thomas J; Ravindranath, Thyyar M; Bickham, Kara L; Gordon, Claire L; Zhang, Feifan; Levin, Bruce; Baird, John S; Farber, Donna L

    2016-06-01

    Infants and young children are disproportionately susceptible to severe complications from respiratory viruses, although the underlying mechanisms remain unknown. Recent studies show that the T cell response in the lung is important for protective responses to respiratory infections, although details on the infant/pediatric respiratory immune response remain sparse. The objectives of the present study were to characterize the local versus systemic immune response in infants and young children with respiratory failure from viral respiratory tract infections and its association to disease severity. Daily airway secretions were sampled from infants and children 4 years of age and younger receiving mechanical ventilation owing to respiratory failure from viral infection or noninfectious causes. Samples were examined for immune cell composition and markers of T cell activation. These parameters were then correlated with clinical disease severity. Innate immune cells and total CD3(+) T cells were present in similar proportions in airway aspirates derived from infected and uninfected groups; however, the CD8:CD4 T cell ratio was markedly increased in the airways of patients with viral infection compared with uninfected patients, and specifically in infected infants with acute lung injury. T cells in the airways were phenotypically and functionally distinct from those in blood with activated/memory phenotypes and increased cytotoxic capacity. We identified a significant increase in airway cytotoxic CD8(+) T cells in infants with lung injury from viral respiratory tract infection that was distinct from the T cell profile in circulation and associated with increasing disease severity. Airway sampling could therefore be diagnostically informative for assessing immune responses and lung damage. PMID:26618559

  19. Characterization of T cell epitopes in bovine α-lactalbumin

    NARCIS (Netherlands)

    Meulenbroek, Laura A P M; den Hartog Jager, Constance F; Lebens, Ans F M; Knulst, André C; Bruijnzeel-Koomen, Carla A F M; Garssen, Johan; Knippels, Léon M J; van Hoffen, Els

    2014-01-01

    BACKGROUND: Recent studies have indicated that peptides containing T cell epitopes may be used for immunotherapy. While for several cow's milk allergens the T cell epitopes have been described, the T cell epitopes in the major allergen α-lactalbumin (α-LAC) are unknown. Therefore, the aim of this st

  20. CD8+ T Cell Immunodominance in Lymphocytic Choriomeningitis Virus Infection Is Modified in the Presence of Toll-Like Receptor Agonists ▿

    OpenAIRE

    Siddiqui, Sarah; Basta, Sameh

    2011-01-01

    Currently, we have limited understanding of how Toll-like receptor (TLR) engagement by microbial products influences the immune response during a concurrent virus infection. In this study, we established that dual TLR2 plus TLR3 (designated TLR2+3) stimulation alters the immunodominance hierarchies of lymphocytic choriomeningitis virus (LCMV) epitopes by reducing NP396-specific CD8+ T cell responses and shifting it to a subdominant position. The shift in immunodominance occurred due to a redu...

  1. STAT3 Regulates Proliferation and Survival of CD8+ T Cells: Enhances Effector Responses to HSV-1 Infection, and Inhibits IL-10+ Regulatory CD8+ T Cells in Autoimmune Uveitis

    Directory of Open Access Journals (Sweden)

    Cheng-Rong Yu

    2013-01-01

    Full Text Available STAT3 regulates CD4+ T cell survival and differentiation. However, its effects on CD8+ T cells are not well understood. Here, we show that in comparison to WT CD8+ T cells, STAT3-deficient CD8+ T cells exhibit a preactivated memory-like phenotype, produce more IL-2, proliferate faster, and are more sensitive to activation-induced cell death (AICD. The enhanced proliferation and sensitivity to AICD correlated with downregulation of class-O forkhead transcription factors (FoxO1, FoxO3A, , , Bcl-2, OX-40, and upregulation of FasL, Bax, and Bad. We examined whether STAT3-deficient CD8+ T cells can mount effective response during herpes simplex virus (HSV-1 infection and experimental autoimmune uveitis (EAU. Compared to WT mice, HSV-1-infected STAT3-deficient mice (STAT3KO produced less IFN- and virus-specific KLRG-1+ CD8+ T cells. STAT3KO mice are also resistant to EAU and produced less IL-17-producing Tc17 cells. Resistance of STAT3KO to EAU correlated with marked expansion of IL-10-producing regulatory CD8+ T cells (CD8-Treg implicated in recovery from autoimmune encephalomyelitis. Thus, increases of IL-6-induced STAT3 activation observed during inflammation may inhibit expansion of CD8-Tregs, thereby impeding recovery from uveitis. These results suggest that STAT3 is a potential therapeutic target for upregulating CD8+ T cell-mediated responses to viruses and suggest the successful therapeutic targeting of STAT3 as treatment for uveitis, derived, in part, from promoting CD8-Treg expansion.

  2. Differential Frequency of CD8+ T Cell Subsets in Multiple Sclerosis Patients with Various Clinical Patterns.

    Science.gov (United States)

    Salehi, Zahra; Doosti, Rozita; Beheshti, Masoumeh; Janzamin, Ehsan; Sahraian, Mohammad Ali; Izad, Maryam

    2016-01-01

    Recent evidence points to a pathogenic role for CD8+ cytotoxic T (Tc) cells in Multiple sclerosis (MS). Based on cytokine profile, Tc cells can be divided into different subsets: IFN-γ (Tc1), IL-4 (Tc2), IL-10 (Tc10), IL-17 (Tc17), IL-21 (Tc21), IL-22 (Tc22) and TNF-α producing cells. In this study we evaluated the frequency of Tc cell subsets and the serum level of Tc17 differentiation cytokines in MS patients with different clinical patterns. We analyzed Tc cell subsets percentage in peripheral blood of relapsing-remitting (RRMS) (n = 28), secondary-progressive (SPMS) (n = 10) and primary-progressive (PPMS) (n = 4) MS patients in comparison to healthy controls (n = 15) using flow cytometry. Serum level of TGF-β, IL-6 and IL-23 were measured by ELISA. We showed elevated levels of Tc1 and Tc17 cells in SPMS and RRMS patients in relapse phase, respectively (P = 0.04). Interestingly, the percentage of TNF-α producing CD8+ T cells in relapse and remission phase of RRMS and SPMS patients were higher than controls (P = 0.01, P = 0.004, P = 0.01, respectively) and Tc21 increased in remission phase of RRMS compared to SPMS (P = 0.03). We also found higher frequency of CD8+ IFN-γ+ TNF-α+ IL-17+ T cells in relapse phase of RRMS compared to remission phase, SPMS patients and controls (P = 0.01, P = 0.004 and P = 0.02, respectively). TGF- β increased in sera of RRMS patients in remission phase (P = 0.03) and SPMS (P = 0.05) compared to healthy subjects. Increased level of Tc17 and CD8+ IFN-γ+ TNF-α+ IL-17+ T cells in relapse phase highlights the critical role of IL-17 in RRMS pathogenesis. PMID:27467597

  3. Human mesenchymal stem cells are susceptible to lysis by CD8(+) T cells and NK cells.

    Science.gov (United States)

    Crop, Meindert J; Korevaar, Sander S; de Kuiper, Ronella; IJzermans, Jan N M; van Besouw, Nicole M; Baan, Carla C; Weimar, Willem; Hoogduijn, Martin J

    2011-01-01

    There is growing interest in the use of mesenchymal stem cells (MSCs) to improve the outcome of organ transplantation. The immunogenicity of MSCs is, however, unclear and is important for the efficacy of MSC therapy and for potential sensitization against donor antigens. We investigated the susceptibility of autologous and allogeneic MSCs for lysis by CD8(+) T-lymphocytes and NK cells in a kidney transplant setting. MSCs were derived from adipose tissue of human kidney donors and were CD90(+), CD105(+), CD166(+), and HLA class I(+). They showed differentiation ability and immunosuppressive capacity. Lysis of MSCs by peripheral blood mononuclear cells (PBMCs), FACS-sorted CD8(+) T cells, and NK cells was measured by europium release assay. Allogeneic MSCs were susceptible for lysis by cytotoxic CD8(+) T cells and NK cells, while autologous MSCs were lysed by NK cells only. NK cell-mediated lysis was inversely correlated with the expression of HLA class I on MSCs. Lysis of autologous MSCs was not dependent on culturing of MSCs in FBS, and MSCs in suspension as well as adherent to plastic were lysed by NK cells. Pretransplant recipient PBMCs did not lyse donor MSCs, but PBMCs isolated 3, 6, and 12 months after transplantation showed increasing lysing ability. After 12 months, CD8(+) T-cell-mediated lysis of donor MSCs persisted, indicating there was no evidence for desensitization against donor MSCs. Lysis of MSCs is important to take into account when MSCs are considered for clinical application. Our results suggest that the HLA background of MSCs and timing of MSC administration are important for the efficacy of MSC therapy. PMID:21396164

  4. Sustained CD8+ T cell memory inflation after infection with a single-cycle cytomegalovirus.

    Directory of Open Access Journals (Sweden)

    Christopher M Snyder

    2011-10-01

    Full Text Available Cytomegalovirus (CMV is a β-herpesvirus that establishes a lifelong latent or persistent infection. A hallmark of chronic CMV infection is the lifelong persistence of large numbers of virus-specific CD8+ effector/effector memory T cells, a phenomenon called "memory inflation". How the virus continuously stimulates these T cells without being eradicated remains an enigma. The prevailing view is that CMV establishes a low grade "smoldering" infection characterized by tiny bursts of productive infection which are rapidly extinguished, leaving no detectable virus but replenishing the latent pool and leaving the immune system in a highly charged state. However, since abortive reactivation with limited viral gene expression is known to occur commonly, we investigated the necessity for virus reproduction in maintaining the inflationary T cell pool. We inhibited viral replication or spread in vivo using two different mutants of murine CMV (MCMV. First, famcyclovir blocked the replication of MCMV encoding the HSV Thymidine Kinase gene, but had no impact on the CD8+ T cell memory inflation once the infection was established. Second, MCMV that lacks the essential glycoprotein L, and thus is completely unable to spread from cell to cell, also drove memory inflation if the virus was administered systemically. Our data suggest that CMV which cannot spread from the cells it initially infects can repeatedly generate viral antigens to drive memory inflation without suffering eradication of the latent genome pool.

  5. Depletion of CD25+CD4+T cells (Tregs) enhances the HBV-specific CD8+ T cell response primed by DNA immunization

    Institute of Scientific and Technical Information of China (English)

    Yoshihiro Furuichi; Hirotake Tokuyama; Satoshi Ueha; Makoto Kurachi; Fuminori Moriyasu; Kazuhiro Kakimi

    2005-01-01

    AIM: Persistent hepatitis B virus (HBV) infection is characterized by a weak CD8+ T cell response to HBV. Immunotherapeutic strategies that overcome tolerance and boost these suboptimal responses may facilitate viral clearance in chronically infected individuals. Therefore, we examined whether CD25+CD4+ regulatory T (Treg) cells might be involved in a inhibition of CD8+T cell priming or in the modulation of the magnitude of the'peak' antiviral CD8+ T cell response primed by DNA immunization. METHODS: B10.D2 mice were immunized once with plasmid pCMV-S. Mice received 500 μg of anti-CD25 mAb injected intraperitoneally 3 d before DNA immunization to deplete CD25+ cells. Induction of HBV-specific CD8+ T ceils in peripheral blood mononuclear cells (PBMCs) was measured by S28-39 peptide loaded DimerX staining and their function was analyzed by intracellular IFN-γ staining.RESULTS: DNA immunization induced HBV-specific CD8+ T cells. At the peak T cell response (d 10), 7.1±2.0% of CD8+ T cells were HBV-specific after DNA immunization, whereas 12.7±3.2% of CD8+ T cells were HBV-specific in Treg-depleted mice, suggesting that DNA immunization induced more antigen-specific CD8+ T cells in the absence of CD25+ Treg cells (n = 6, P<0.05). Similarly, fewer HBVspecific memory T cells were detected in the presence of these cells (1.3±0.4%) in comparison to Treg-depleted mice (2.6±0.9%) on d 30 after DNA immunization (n = 6, P<0.01). Both IFN-γ production and the avidity of the HBV-specific CD8+ T cell response to antigen were higher in HBV-specific CD8+ T cells induced in the absence of Treg cells.CONCLUSION: CD25+ Treg cells suppress priming and/or expansion of antigen-specific CD8+ T cells during DNA immunization and the peak CD8+ T cell response is enhanced by depleting this cell population. Furthermore, Treg cells appear to be involved in the contraction phase of the CD8+ T ceil response and may affect the quality of memory T cell pools. The elimination of Treg

  6. Sequence conservation of subdominant HLA-A2-binding CTL epitopes in HIV-1 clinical isolates and CD8+ T-lymphocyte cross-recognition may explain the immune reaction in infected individuals

    DEFF Research Database (Denmark)

    Thorn, Mette; Tang, Sheila; Therrien, Dominic;

    2007-01-01

    Cytotoxic T-lymphocytes (CTL) are critical for immune control of infection with human immunodeficiency virus type-1 (HIV-1) and searches for relevant CTL epitopes for immune therapy are ongoing. Recently, we identified 28 HLA-A2-binding HIV-1 CTL epitopes (1). In this follow-up study we fully...... genome sequenced HIV-1 from 11 HLA-A2(+) patients to examine the sequence variation of these natural epitopes and compared them with the patient's CD8(+) T-cell recall response. Often the epitope was conserved but only a few patients showed a CD8(+) T-cell recall response. This infrequent targeting may...... be explained by immune subdominance. CD8(+) T-cell recall response to a natural epitope could be measured despite sequence differences in the patient's virus. T-cell cross-reaction between such variants could be demonstrated in HLA-A2 transgenic mice. Nine infrequently targeted but conserved or cross...

  7. C-Myc regulation by costimulatory signals modulates the generation of CD8+ memory T cells during viral infection.

    Science.gov (United States)

    Haque, Mohammad; Song, Jianyong; Fino, Kristin; Wang, Youfei; Sandhu, Praneet; Song, Xinmeng; Norbury, Christopher; Ni, Bing; Fang, Deyu; Salek-Ardakani, Shahram; Song, Jianxun

    2016-01-01

    The signalling mechanisms of costimulation in the development of memory T cells remain to be clarified. Here, we show that the transcription factor c-Myc in CD8(+) T cells is controlled by costimulatory molecules, which modulates the development of memory CD8(+) T cells. C-Myc expression was dramatically reduced in Cd28(-/-) or Ox40(-/-) memory CD8(+) T cells, and c-Myc over-expression substantially reversed the defects in the development of T-cell memory following viral infection. C-Myc regulated the expression of survivin, an inhibitor of apoptosis, which promoted the generation of virus-specific memory CD8(+) T cells. Moreover, over-expression of survivin with bcl-xL, a downstream molecule of NF-κB and intracellular target of costimulation that controls survival, in Cd28(-/-) or Ox40(-/-) CD8(+) T cells, reversed the defects in the generation of memory T cells in response to viral infection. These results identify c-Myc as a key controller of memory CD8(+) T cells from costimulatory signals.

  8. C-Myc regulation by costimulatory signals modulates the generation of CD8+ memory T cells during viral infection.

    Science.gov (United States)

    Haque, Mohammad; Song, Jianyong; Fino, Kristin; Wang, Youfei; Sandhu, Praneet; Song, Xinmeng; Norbury, Christopher; Ni, Bing; Fang, Deyu; Salek-Ardakani, Shahram; Song, Jianxun

    2016-01-01

    The signalling mechanisms of costimulation in the development of memory T cells remain to be clarified. Here, we show that the transcription factor c-Myc in CD8(+) T cells is controlled by costimulatory molecules, which modulates the development of memory CD8(+) T cells. C-Myc expression was dramatically reduced in Cd28(-/-) or Ox40(-/-) memory CD8(+) T cells, and c-Myc over-expression substantially reversed the defects in the development of T-cell memory following viral infection. C-Myc regulated the expression of survivin, an inhibitor of apoptosis, which promoted the generation of virus-specific memory CD8(+) T cells. Moreover, over-expression of survivin with bcl-xL, a downstream molecule of NF-κB and intracellular target of costimulation that controls survival, in Cd28(-/-) or Ox40(-/-) CD8(+) T cells, reversed the defects in the generation of memory T cells in response to viral infection. These results identify c-Myc as a key controller of memory CD8(+) T cells from costimulatory signals. PMID:26791245

  9. Purification of Plasmodium Sporozoites Enhances Parasite-Specific CD8+ T Cell Responses.

    Science.gov (United States)

    Billman, Zachary P; Seilie, Annette M; Murphy, Sean C

    2016-08-01

    Malaria infection caused by Plasmodium parasites continues to cause enormous morbidity and mortality in areas where it is endemic, and there is no licensed vaccine capable of inducing sterile protection. Hyperimmunization with attenuated whole sporozoites can induce sterile protective immune responses targeting preerythrocytic antigens. Most animal models of hyperimmunization rely on sporozoites dissected from mosquito salivary glands and injected without further purification. In BALB/c mice, repeated small doses of P. yoelii sporozoites progressively expand the population of sporozoite-specific CD8(+) T cells. In this study, large secondary doses of unpurified sporozoites unexpectedly led to contraction of sporozoite-specific CD8(+) T cell responses in sporozoite-primed mice. While sporozoite-primed CD8(+) T cells alternatively can be expanded by secondary exposure to Listeria monocytogenes expressing recombinant Plasmodium antigens, such expansion was potently inhibited by coinjection of large doses of unpurified sporozoites and by uninfected salivary glands alone. Purification of sporozoites away from mosquito salivary gland debris by density gradient centrifugation eliminated salivary gland-associated inhibition. Thus, the inhibitory effect appears to be due to exposure to uninfected mosquito salivary glands rather than sporozoites. To further assess the effect of salivary gland exposure on later sporozoite vaccinations, mice were immunized with uninfected salivary glands from a single mosquito. Compared to naive mice, salivary gland presensitization reduced subsequent liver burdens by 71%. These data show that a component(s) in mosquito salivary glands reduces liver infection, thereby limiting antigen dose and contributing to lower-magnitude T cell responses. These findings suggest that sporozoite immunogenicity studies be performed using purified sporozoites whenever feasible. PMID:27217420

  10. Pre-existing vector immunity does not prevent replication deficient adenovirus from inducing efficient CD8 T-cell memory and recall responses

    DEFF Research Database (Denmark)

    Steffensen, Maria Abildgaard; Jensen, Benjamin Anderschou Holbech; Holst, Peter Johannes;

    2012-01-01

    directed against epitopes in the adenoviral vector seemed to correlate with repression of the induced response in re-vaccinated B-cell deficient mice. More importantly, despite a repressed primary effector CD8 T-cell response in Ad5-immune animals subjected to vaccination, memory T cells were generated......Adenoviral vectors have shown a great potential for vaccine development due to their inherent ability to induce potent and protective CD8 T-cell responses. However, a critical issue regarding the use of these vectors is the existence of inhibitory immunity against the most commonly used Ad5 vector...... in a large part of the human population. We have recently developed an improved adenoviral vaccine vector system in which the vector expresses the transgene tethered to the MHC class II associated invariant chain (Ii). To further evaluate the potential of this system, the concept of pre-existing inhibitory...

  11. Two Theileria parva CD8 T cell antigen genes are more variable in buffalo than cattle parasites, but differ in pattern of sequence diversity.

    Directory of Open Access Journals (Sweden)

    Roger Pelle

    Full Text Available BACKGROUND: Theileria parva causes an acute fatal disease in cattle, but infections are asymptomatic in the African buffalo (Syncerus caffer. Cattle can be immunized against the parasite by infection and treatment, but immunity is partially strain specific. Available data indicate that CD8(+ T lymphocyte responses mediate protection and, recently, several parasite antigens recognised by CD8(+ T cells have been identified. This study set out to determine the nature and extent of polymorphism in two of these antigens, Tp1 and Tp2, which contain defined CD8(+ T-cell epitopes, and to analyse the sequences for evidence of selection. METHODOLOGY/PRINCIPAL FINDINGS: Partial sequencing of the Tp1 gene and the full-length Tp2 gene from 82 T. parva isolates revealed extensive polymorphism in both antigens, including the epitope-containing regions. Single nucleotide polymorphisms were detected at 51 positions (∼12% in Tp1 and in 320 positions (∼61% in Tp2. Together with two short indels in Tp1, these resulted in 30 and 42 protein variants of Tp1 and Tp2, respectively. Although evidence of positive selection was found for multiple amino acid residues, there was no preferential involvement of T cell epitope residues. Overall, the extent of diversity was much greater in T. parva isolates originating from buffalo than in isolates known to be transmissible among cattle. CONCLUSIONS/SIGNIFICANCE: The results indicate that T. parva parasites maintained in cattle represent a subset of the overall T. parva population, which has become adapted for tick transmission between cattle. The absence of obvious enrichment for positively selected amino acid residues within defined epitopes indicates either that diversity is not predominantly driven by selection exerted by host T cells, or that such selection is not detectable by the methods employed due to unidentified epitopes elsewhere in the antigens. Further functional studies are required to address this latter

  12. Immunotherapy-induced CD8+ T Cells Instigate Immune Suppression in the Tumor

    Science.gov (United States)

    McGray, A J Robert; Hallett, Robin; Bernard, Dannie; Swift, Stephanie L; Zhu, Ziqiang; Teoderascu, Florentina; VanSeggelen, Heather; Hassell, John A; Hurwitz, Arthur A; Wan, Yonghong; Bramson, Jonathan L

    2014-01-01

    Despite clear evidence of immunogenicity, cancer vaccines only provide a modest clinical benefit. To evaluate the mechanisms that limit tumor regression following vaccination, we have investigated the weak efficacy of a highly immunogenic experimental vaccine using a murine melanoma model. We discovered that the tumor adapts rapidly to the immune attack instigated by tumor-specific CD8+ T cells in the first few days following vaccination, resulting in the upregulation of a complex set of biological networks, including multiple immunosuppressive processes. This rapid adaptation acts to prevent sustained local immune attack, despite continued infiltration by increasing numbers of tumor-specific T cells. Combining vaccination with adoptive transfer of tumor-specific T cells produced complete regression of the treated tumors but did not prevent the adaptive immunosuppression. In fact, the adaptive immunosuppressive pathways were more highly induced in regressing tumors, commensurate with the enhanced level of immune attack. Examination of tumor infiltrating T-cell functionality revealed that the adaptive immunosuppression leads to a progressive loss in T-cell function, even in tumors that are regressing. These novel observations that T cells produced by therapeutic intervention can instigate a rapid adaptive immunosuppressive response within the tumor have important implications for clinical implementation of immunotherapies. PMID:24196579

  13. CD8+ Tumor-Infiltrating T Cells Are Trapped in the Tumor-Dendritic Cell Network

    Directory of Open Access Journals (Sweden)

    Alexandre Boissonnas

    2013-01-01

    Full Text Available Chemotherapy enhances the antitumor adaptive immune T cell response, but the immunosuppressive tumor environment often dominates, resulting in cancer relapse. Antigen-presenting cells such as tumor-associated macrophages (TAMs and tumor dendritic cells (TuDCs are the main protagonists of tumor-infiltrating lymphocyte (TIL immuno-suppression. TAMs have been widely investigated and are associated with poor prognosis, but the immuno-suppressive activity of TuDCs is less well understood. We performed two-photon imaging of the tumor tissue to examine the spatiotemporal interactions between TILs and TuDCs after chemotherapy. In a strongly immuno-suppressive murine tumor model, cyclophosphamide-mediated chemotherapy transiently enhanced the antitumor activity of adoptively transferred ovalbumin-specific CD8+ T cell receptor transgenic T cells (OTI but barely affected TuDC compartment within the tumor. Time lapse imaging of living tumor tissue showed that TuDCs are organized as a mesh with dynamic interconnections. Once infiltrated into the tumor parenchyma, OTI T cells make antigen-specific and long-lasting contacts with TuDCs. Extensive analysis of TIL infiltration on histologic section revealed that after chemotherapy the majority of OTI T cells interact with TuDCs and that infiltration is restricted to TuDC-rich areas. We propose that the TuDC network exerts antigen-dependent unproductive retention that trap T cells and limit their antitumor effectiveness.

  14. The effect of aging and caloric restriction on murine CD8+ T cell chemokine receptor gene expression

    Directory of Open Access Journals (Sweden)

    Mo RuRan

    2007-11-01

    Full Text Available Abstract Background The mechanism explaining the increased disease susceptibility in aging is not well understood. CD8+ T cells are crucial in anti-viral and anti-tumor responses. Although the chemokine system plays a critical role in CD8+ T cell function, very little is known about the relationship between aging and the T cell chemokine system. Results In this study we have examined the effect of aging on murine CD8+ T cell chemokine receptor gene expression. Freshly isolated splenic CD8+ T cells from old C57BL/6 mice were found to have higher CCR1, CCR2, CCR4, CCR5 and CXCR5, and lower CCR7 gene expression compared to their younger cohort. Anti-CD3/anti-CD28 stimulation elicited a similar robust chemokine receptor response from young and old CD8+ T cells. Western blot analyses confirmed elevated protein level of CCR4 and CCR5 in aged CD8+ T cells. Increases in T cell CCR1 and CCR5 expression also correlate to increased in vitro chemotaxis response to macrophage-inflammatory protein-1 α(MIP-1α. Finally, caloric restriction selectively prevents the loss of CD8+ T cell CCR7 gene expression in aging to the level that is seen in young CD8+ T cells. Conclusion These findings are consistent with the notion that aging exists in a state of low grade pro-inflammatory environment. In addition, our results provide a potential mechanism for the reported aging-associated impaired T cell lymphoid homing and allograft response, and reduced survival in sepsis.

  15. CD4+ T Cell Help Guides Formation of CD103+ Lung-Resident Memory CD8+ T Cells during Influenza Viral Infection

    Science.gov (United States)

    Laidlaw, Brian J.; Zhang, Nianzhi; Marshall, Heather D.; Staron, Mathew M.; Guan, Tianxia; Hu, Yinghong; Cauley, Linda S.; Craft, Joe; Kaech, Susan M.

    2014-01-01

    SUMMARY Tissue-resident memory T (Trm) cells provide enhanced protection against infection at mucosal sites. Here we found that CD4+ T cells are important for the formation of functional lung-resident CD8+ T cells after influenza virus infection. In the absence of CD4+ T cells, CD8+ T cells displayed reduced expression of CD103 (Itgae), were mislocalized away from airway epithelia, and demonstrated an impaired ability to recruit CD8+ T cells to the lung air-ways upon heterosubtypic challenge. CD4+ T cell-derived interferon-γ was necessary for generating lung-resident CD103+ CD8+ Trm CD8 T cells. Furthermore, expression of the transcription factor T-bet was increased in “unhelped” lung Trm cells, and a reduction in T-bet rescued CD103 expression in the absence of CD4+ T cell help. Thus, CD4+ T cell-dependent signals are important to limit expression of T-bet and allow for the development of CD103+ CD8+ Trm cells in the lung airways following respiratory infection. PMID:25308332

  16. Diminished primary and secondary influenza virus-specific CD8(+) T-cell responses in CD4-depleted Ig(-/-) mice

    DEFF Research Database (Denmark)

    Riberdy, J M; Christensen, Jan Pravsgaard; Branum, K;

    2000-01-01

    Optimal expansion of influenza virus nucleoprotein (D(b)NP(366))-specific CD8(+) T cells following respiratory challenge of naive Ig(-/-) microMT mice was found to require CD4(+) T-cell help, and this effect was also observed in primed animals. Absence of the CD4(+) population was consistently...... correlated with diminished recruitment of virus-specific CD8(+) T cells to the infected lung, delayed virus clearance, and increased morbidity. The splenic CD8(+) set generated during the recall response in Ig(-/-) mice primed at least 6 months previously showed a normal profile of gamma interferon...... production subsequent to short-term, in vitro stimulation with viral peptide, irrespective of a concurrent CD4(+) T-cell response. Both the magnitude and the localization profiles of virus-specific CD8(+) T cells, though perhaps not their functional characteristics, are thus modified in mice lacking CD4(+) T...

  17. Intravacuolar Membranes Regulate CD8 T Cell Recognition of Membrane-Bound Toxoplasma gondii Protective Antigen.

    Science.gov (United States)

    Lopez, Jodie; Bittame, Amina; Massera, Céline; Vasseur, Virginie; Effantin, Grégory; Valat, Anne; Buaillon, Célia; Allart, Sophie; Fox, Barbara A; Rommereim, Leah M; Bzik, David J; Schoehn, Guy; Weissenhorn, Winfried; Dubremetz, Jean-François; Gagnon, Jean; Mercier, Corinne; Cesbron-Delauw, Marie-France; Blanchard, Nicolas

    2015-12-15

    Apicomplexa parasites such as Toxoplasma gondii target effectors to and across the boundary of their parasitophorous vacuole (PV), resulting in host cell subversion and potential presentation by MHC class I molecules for CD8 T cell recognition. The host-parasite interface comprises the PV limiting membrane and a highly curved, membranous intravacuolar network (IVN) of uncertain function. Here, using a cell-free minimal system, we dissect how membrane tubules are shaped by the parasite effectors GRA2 and GRA6. We show that membrane association regulates access of the GRA6 protective antigen to the MHC I pathway in infected cells. Although insertion of GRA6 in the PV membrane is key for immunogenicity, association of GRA6 with the IVN limits presentation and curtails GRA6-specific CD8 responses in mice. Thus, membrane deformations of the PV regulate access of antigens to the MHC class I pathway, and the IVN may play a role in immune modulation. PMID:26628378

  18. CD8+ T-Cells Count in Acute Myocardial Infarction in HIV Disease in a Predominantly Male Cohort

    Directory of Open Access Journals (Sweden)

    Oluwatosin A. Badejo

    2015-01-01

    Full Text Available Human Immunodeficiency Virus- (HIV- infected persons have a higher risk for acute myocardial infarction (AMI than HIV-uninfected persons. Earlier studies suggest that HIV viral load, CD4+ T-cell count, and antiretroviral therapy are associated with cardiovascular disease (CVD risk. Whether CD8+ T-cell count is associated with CVD risk is not clear. We investigated the association between CD8+ T-cell count and incident AMI in a cohort of 73,398 people (of which 97.3% were men enrolled in the U.S. Veterans Aging Cohort Study-Virtual Cohort (VACS-VC. Compared to uninfected people, HIV-infected people with high baseline CD8+ T-cell counts (>1065 cells/mm3 had increased AMI risk (adjusted HR=1.82, P<0.001, 95% CI: 1.46 to 2.28. There was evidence that the effect of CD8+ T-cell tertiles on AMI risk differed by CD4+ T-cell level: compared to uninfected people, HIV-infected people with CD4+ T-cell counts ≥200 cells/mm3 had increased AMI risk with high CD8+ T-cell count, while those with CD4+ T-cell counts <200 cells/mm3 had increased AMI risk with low CD8+ T-cell count. CD8+ T-cell counts may add additional AMI risk stratification information beyond that provided by CD4+ T-cell counts alone.

  19. Linear fidelity in quantification of anti-viral CD8+ T cells.

    Science.gov (United States)

    Flesch, Inge E A; Hollett, Natasha A; Wong, Yik Chun; Tscharke, David C

    2012-01-01

    Enumeration of anti-viral CD8(+) T cells to make comparisons between mice, viruses and vaccines is a frequently used approach, but controversy persists as to the most appropriate methods. Use of peptide-MHC tetramers (or variants) and intracellular staining for cytokines, in particular IFNγ, after a short ex vivo stimulation are now common, as are a variety of cytotoxicity assays, but few direct comparisons have been made. It has been argued that use of tetramers leads to the counting of non-functional T cells and that measurement of single cytokines will fail to identify cells with alternative functions. Further, the linear range of these methods has not been tested and this is required to give confidence that relative quantifications can be compared across samples. Here we show for two acute virus infections and CD8(+) T cells activated in vitro that DimerX (a tetramer variant) and intracellular staining for IFNγ, alone or in combination with CD107 to detect degranulation, gave comparable results at the peak of the response. Importantly, these methods were highly linear over nearly two orders of magnitude. In contrast, in vitro and in vivo assays for cytotoxicity were not linear, suffering from high background killing, plateaus in maximal killing and substantial underestimation of differences in magnitude of responses. PMID:22745779

  20. Linear fidelity in quantification of anti-viral CD8+ T cells.

    Directory of Open Access Journals (Sweden)

    Inge E A Flesch

    Full Text Available Enumeration of anti-viral CD8(+ T cells to make comparisons between mice, viruses and vaccines is a frequently used approach, but controversy persists as to the most appropriate methods. Use of peptide-MHC tetramers (or variants and intracellular staining for cytokines, in particular IFNγ, after a short ex vivo stimulation are now common, as are a variety of cytotoxicity assays, but few direct comparisons have been made. It has been argued that use of tetramers leads to the counting of non-functional T cells and that measurement of single cytokines will fail to identify cells with alternative functions. Further, the linear range of these methods has not been tested and this is required to give confidence that relative quantifications can be compared across samples. Here we show for two acute virus infections and CD8(+ T cells activated in vitro that DimerX (a tetramer variant and intracellular staining for IFNγ, alone or in combination with CD107 to detect degranulation, gave comparable results at the peak of the response. Importantly, these methods were highly linear over nearly two orders of magnitude. In contrast, in vitro and in vivo assays for cytotoxicity were not linear, suffering from high background killing, plateaus in maximal killing and substantial underestimation of differences in magnitude of responses.

  1. T-bet and Eomes Are Differentially Linked to the Exhausted Phenotype of CD8+T Cells in HIV Infection

    DEFF Research Database (Denmark)

    Buggert, Marcus; Tauriainen, Johanna; Yamamoto, Takuya;

    2014-01-01

    CD8+ T cell exhaustion represents a major hallmark of chronic HIV infection. Two key transcription factors governing CD8+ T cell differentiation, T-bet and Eomesodermin (Eomes), have previously been shown in mice to differentially regulate T cell exhaustion in part through direct modulation of PD...... to an inverse expression balance between T-bet and Eomes, which is not reversed despite long-term viral control through ART. These results aid to explain the inability of HIV-specific CD8+ T cells to control the viral replication post-ART cessation.......CD8+ T cell exhaustion represents a major hallmark of chronic HIV infection. Two key transcription factors governing CD8+ T cell differentiation, T-bet and Eomesodermin (Eomes), have previously been shown in mice to differentially regulate T cell exhaustion in part through direct modulation of PD-1....... Here, we examined the relationship between these transcription factors and the expression of several inhibitory receptors (PD-1, CD160, and 2B4), functional characteristics and memory differentiation of CD8+ T cells in chronic and treated HIV infection. The expression of PD-1, CD160, and 2B4 on total...

  2. Decreased Expression of T-Cell Costimulatory Molecule CD28 on CD4 and CD8 T Cells of Mexican Patients with Pulmonary Tuberculosis

    Directory of Open Access Journals (Sweden)

    German Bernal-Fernandez

    2010-01-01

    Full Text Available Patients with tuberculosis frequently develop anergy, a state of T-cell hyporesponsiveness in which defective T-cell costimulation could be a factor. To know if the expression of T-cell costimulatory molecules was altered in tuberculosis, we analyzed the peripheral blood T-cell phenotype of 23 Mexican patients with pulmonary tuberculosis. There was severe CD4 (P<.001 and CD8 (P<.01 lymphopenia and upregulation of costimulatory molecule CD30 on CD4 and CD8 T cells (P<.05; this increase was higher in relapsing tuberculosis. The main finding was severe downregulation of the major costimulatory molecule CD28 on both CD8 and CD4 T cells (P<.001. Depletion of the CD4/CD28 subset, a hitherto undescribed finding, is relevant because CD4 T cells constitute the main arm of the cell-mediated antimycobacterial immune response.

  3. Alpha 4 integrin directs virus-activated CD8+ T cells to sites of infection

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Andersson, E C; Scheynius, A;

    1995-01-01

    This article examines the role of VLA-4 in directing lymphocytes to sites of viral infection using the murine lymphocytic choriomeningitis virus infection (LCMV) as the model system. This virus by itself induces little or no inflammation, but in most mouse/virus strain combinations a potent T cell...... response is induced, which is associated with marked CD8+ cell-mediated inflammation. Two expressions of LCMV-induced inflammation were studied: meningitis induced by intracerebral infection and adoptive transfer of virus-specific delayed-type hypersensitivity. Our previous studies have shown that LCMV...

  4. Tc17 CD8 T Cells: Functional Plasticity and Subset Diversity1

    OpenAIRE

    Yen, Hung-Rong; Harris, Timothy J.; Wada, Satoshi; Grosso, Joseph F.; Getnet, Derese; Goldberg, Monica V.; Liang, Kai-Li; Bruno, Tullia C.; Pyle, Kristin J.; Chan, Siaw-Li; Anders, Robert A.; Trimble, Cornelia L.; Adler, Adam J.; Lin, Tzou-Yien; Pardoll, Drew M.

    2009-01-01

    IL-17-secreting CD8 T cells (Tc17) have been described in several settings, but little is known regarding their functional characteristics. While Tc1 cells produced IFN-γ and efficiently killed targets, Tc17 cells lacked lytic function in vitro. Interestingly, the small numbers of IFN-γ-positive or IL-17/IFN-γ-double-positive cells generated under Tc17 conditions also lacked lytic activity and expressed a similar pattern of cell surface proteins to IL-17-producing cells. As is the case for Th...

  5. Conditional ligands for Asian HLA variants facilitate the definition of CD8+ T-cell responses in acute and chronic viral diseases

    DEFF Research Database (Denmark)

    Chang, Cynthia X L; Tan, Anthony T; Or, Ming Yan;

    2013-01-01

    exchange was accomplished for all variants as demonstrated by an ELISA-based MHC stability assay. HLA tetramers with redirected specificity could detect antigen-specific CD8(+) T-cell responses against human cytomegalovirus, hepatitis B (HBV), dengue virus (DENV), and Epstein-Barr virus (EBV) infections....... The potential of this population-centric HLA library was demonstrated with the characterization of seven novel T-cell epitopes from severe acute respiratory syndrome coronavirus, HBV, and DENV. Posthoc analysis revealed that the majority of responses would be more readily identified by our unbiased discovery...... approach than through the application of state-of-the-art epitope prediction. This flow cytometry-based technology therefore holds considerable promise for monitoring clinically relevant antigen-specific T-cell responses in populations of distinct ethnicity....

  6. Serine protease inhibitor-6 differentially affects the survival of effector and memory alloreactive CD8-T cells.

    Science.gov (United States)

    Azzi, J; Ohori, S; Ting, C; Uehara, M; Abdoli, R; Smith, B D; Safa, K; Solhjou, Z; Lukyanchykov, P; Patel, J; McGrath, M; Abdi, R

    2015-01-01

    The clonal expansion of effector T cells and subsequent generation of memory T cells are critical in determining the outcome of transplantation. While cytotoxic T lymphocytes induce direct cytolysis of target cells through secretion of Granzyme-B (GrB), they also express cytoplasmic serine protease inhibitor-6 (Spi6) to protect themselves from GrB that has leaked from granules. Here, we studied the role of GrB/Spi6 axis in determining clonal expansion of alloreactive CD8-T cells and subsequent generation of memory CD8-T cells in transplantation. CD8-T cells from Spi6(-/-) mice underwent more GrB mediated apoptosis upon alloantigen stimulation in vitro and in vivo following adoptive transfer into an allogeneic host. Interestingly, while OT1.Spi6(-/-) CD8 T cells showed significantly lower clonal expansion following skin transplants from OVA mice, there was no difference in the size of the effector memory CD8-T cells long after transplantation. Furthermore, lack of Spi6 resulted in a decrease of short-lived-effector-CD8-cells but did not impact the pool of memory-precursor-effector-CD8-cells. Similar results were found in heart transplant models. Our findings suggest that the final alloreactive CD8-memory-pool-size is independent from the initial clonal-proliferation as memory precursors express low levels of GrB and therefore are independent of Spi6 for survival. These data advance our understanding of memory T cells generation in transplantation and provide basis for Spi6 based strategies to target effector T cells.

  7. CD8(+) T cells mediate RAS-induced psoriasis-like skin inflammation through IFN-γ.

    Science.gov (United States)

    Gunderson, Andrew J; Mohammed, Javed; Horvath, Frank J; Podolsky, Michael A; Anderson, Cherie R; Glick, Adam B

    2013-04-01

    The RAS signaling pathway is constitutively activated in psoriatic keratinocytes. We expressed activated H-RAS(V12G) in suprabasal keratinocytes of adult mice and observed rapid development of a psoriasis-like skin phenotype characterized by basal keratinocyte hyperproliferation, acanthosis, hyperkeratosis, intraepidermal neutrophil microabscesses, and increased T helper type 1 (Th1)/Th17 and T cell type 1 (Tc1)/Tc17 skin infiltration. The majority of skin-infiltrating CD8(+) T cells coexpressed IFN-γ and IL-17A. When RAS was expressed on a Rag1-/- background, microabscess formation, inducible nitric oxide synthase expression, and keratinocyte hyperproliferation were suppressed. Depletion of CD8(+), but not CD4(+), T cells reduced cutaneous and systemic inflammation, the RAS-induced increase in cutaneous Th17 and IL-17(+) γδ T cells, and epidermal hyperproliferation to levels similar to a Rag1-/- background. Reconstitution of Rag1-/- inducible RAS mice with purified CD8(+) T cells restored microabscess formation and epidermal hyperproliferation. Neutralization of IFN-γ, but not of IL-17A, in CD8(+) T-cell-reconstituted Rag1-/- mice expressing RAS blocked CD8-mediated skin inflammation, inducible nitric oxide synthase expression, and keratinocyte hyperproliferation. These results show that CD8(+) T cells can orchestrate skin inflammation with psoriasis-like pathology in response to constitutive RAS activation in keratinocytes, and this is primarily mediated through IFN-γ. PMID:23151849

  8. Phenotypic and Functional Analysis of LCMV gp33-41-Specific CD8 T Cells Elicited by Multiple Peptide Immunization in Mice Revealed the Up-regulation of PD-1 Expression on Antigen Specific CD8 T Cells

    Institute of Scientific and Technical Information of China (English)

    Yi Liu; Lihui Xu; Yiqun Jiang; Jianfang Sun; Xianhui He

    2007-01-01

    The phenotype and function of antigen-specific CD8 T cells are closely associated with the efficacy of a therapeutic vaccination. Here we showed that multiple immunizations with LCMV gp33-41 peptide (KAV) in Freund's adjuvant could induce KAV-specific CD8 T cells with low expression of CD127 and CD62L molecules. The inhibitory receptor PD-1 was also expressed on a substantial part of KAV-specific CD8 T cells, and its expression level on KAV-specific CD8 T cells in spleen and lymph nodes was much higher when compared to those in peripheral blood. Furthermore, KAV-specific CD8 T cells could specifically kill KAV-pulsed target cells in vivo but the efficiency was low. These data suggest that prime-boost vaccination schedule with peptide in Freund's adjuvant can elicit antigen-specific CD8 T cells of effector-like phenotype with partial functional exhaustion, which may only provide short-term protection against the pathogen.

  9. Peripheral blood TIM-3 positive NK and CD8+ T cells throughout pregnancy

    DEFF Research Database (Denmark)

    Meggyes, Matyas; Miko, Eva; Polgar, Beata;

    2014-01-01

    negative regulator of Th1 immunity and tolerance induction. Data about the TIM-3/Gal-9 pathway in the pathogenesis of human diseases is emerging, but their possible role during human pregnancy is not precisely known. The aim of our study was to investigate the number, phenotype and functional activity of...... TIM-3+ peripheral blood mononuclear cells during healthy human pregnancy. METHODS OF STUDY: 57 healthy pregnant women [first trimester (n = 16); second trimester (n = 19); third trimester (n = 22)] and 30 non-pregnant controls were enrolled in the study. We measured the surface expression of TIM-3 by...... cytotoxic T cells, NK cells and NK cell subsets as well as Galectin-9 expression by regulatory T cells by flow cytometry. We analyzed the cytokine production and cytotoxicity of TIM3+ and TIM3- CD8 T and NK cells obtained from non-pregnant and healthy pregnant women at different stages of pregnancy by flow...

  10. Therapeutic targeting of regulatory T cells enhances tumor-specific CD8+ T cell responses in Epstein–Barr virus associated nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Fogg, Mark [Department of Medicine, Brigham and Women' s Hospital (United States); Murphy, John R. [Departments of Medicine and Microbiology, Boston University School of Medicine, Boston, MA 02118 (United States); Lorch, Jochen; Posner, Marshall [Department of Adult Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115 (United States); Wang, Fred, E-mail: fwang@research.bwh.harvard.edu [Department of Medicine, Brigham and Women' s Hospital (United States); Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115 (United States)

    2013-07-05

    Epstein–Barr virus (EBV) is associated with multiple malignancies including nasopharyngeal carcinoma (NPC). In nasopharynx cancer, CD8+ T cells specific for EBV Nuclear Antigen-1 (EBNA-1) and Latent Membrane Protein 2 (LMP2) are important components of anti-tumor immunity since both are consistently expressed in NPC. We have previously shown that EBNA-1-specific CD8+ T cell responses were suppressed in NPC patients compared to healthy controls. We now find that CD8+ T cell responses specific for LMP2 are also abnormal in NPC patients, and both EBNA-1- and LMP2-specific responses are suppressed by regulatory T cells (Treg). EBNA-1 and LMP2-specific CD8+ T cell responses, as well as immune control of EBV-infected cells in vitro, could be restored by the depletion of Tregs and by use of a clinically approved drug targeting Tregs. Thus, in vivo modulation of Tregs may be an effective means of enhancing these anti-tumor immune responses in NPC patients. - Highlights: • Viral proteins are tumor antigens in Epstein–Barr virus associated Nasopharyngeal Carcinoma. • CD8+ T cell responses against EBV proteins EBNA-1 and LMP2 are suppressed in NPC patients. • T regulatory cells are responsible for suppressing EBV immunity in NPC patients. • Depletion of Tregs with Ontak can rescue EBV-specific CD8+ T cell responses in NPC patients. • This clinically approved drug may be effective for enhancing anti-tumor immunity in NPC patients.

  11. The Presence of HLA-E-Restricted, CMV-Specific CD8+ T Cells in the Blood of Lung Transplant Recipients Correlates with Chronic Allograft Rejection.

    Directory of Open Access Journals (Sweden)

    Lucy C Sullivan

    Full Text Available The human cytomegalovirus (CMV immune evasion protein, UL40, shares an identical peptide sequence with that found in the leader sequence of many human leukocyte antigen (HLA-C alleles and when complexed with HLA-E, can modulate NK cell functions via interactions with the CD94-NKG2 receptors. However the UL40-derived sequence can also be immunogenic, eliciting robust CD8+ T cell responses. In the setting of solid organ transplantation these T cells may not only be involved in antiviral immunity but also can potentially contribute to allograft rejection when the UL40 epitope is also present in allograft-encoded HLA. Here we assessed 15 bilateral lung transplant recipients for the presence of HLA-E-restricted UL40 specific T cells by tetramer staining of peripheral blood mononuclear cells (PBMC. UL40-specific T cells were observed in 7 patients post-transplant however the magnitude of the response varied significantly between patients. Moreover, unlike healthy CMV seropositive individuals, longitudinal analyses revealed that proportions of such T cells fluctuated markedly. Nine patients experienced low-grade acute cellular rejection, of which 6 also demonstrated UL40-specific T cells. Furthermore, the presence of UL40-specific CD8+ T cells in the blood was significantly associated with allograft dysfunction, which manifested as Bronchiolitis Obliterans Syndrome (BOS. Therefore, this study suggests that minor histocompatibility antigens presented by HLA-E can represent an additional risk factor following lung transplantation.

  12. TLR activation excludes circulating naive CD8+ T cells from gut-associated lymphoid organs in mice.

    Science.gov (United States)

    Heidegger, Simon; Kirchner, Sophie-Kathrin; Stephan, Nicolas; Bohn, Bernadette; Suhartha, Nina; Hotz, Christian; Anz, David; Sandholzer, Nadja; Stecher, Bärbel; Rüssmann, Holger; Endres, Stefan; Bourquin, Carole

    2013-05-15

    The trafficking of effector T cells is tightly regulated by the expression of site-specific sets of homing molecules. In contrast, naive T cells are generally assumed to express a uniform pattern of homing molecules and to follow a random distribution within the blood and secondary lymphoid organs. In this study, we demonstrate that systemic infection fundamentally modifies the trafficking of circulating naive CD8(+) T cells. We show that on naive CD8(+) T cells, the constitutive expression of the integrin α4β7 that effects their entry into GALT is downregulated following infection of mice with Salmonella typhimurium. We further show that this downregulation is dependent on TLR signaling, and that the TLR-activated naive CD8(+) T cells are blocked from entering GALT. This contrasts strongly with Ag-experienced effector T cells, for which TLR costimulation in the GALT potently upregulates α4β7 and enhances trafficking to intestinal tissues. Thus, TLR activation leads to opposite effects on migration of naive and effector CD8(+) T cells. Our data identify a mechanism that excludes noncognate CD8(+) T cells from selected immune compartments during TLR-induced systemic inflammation. PMID:23589622

  13. CD8 T Cell-Independent Antitumor Response and Its Potential for Treatment of Malignant Gliomas.

    Science.gov (United States)

    Murphy, Katherine A; Griffith, Thomas S

    2016-01-01

    Malignant brain tumors continue to represent a devastating diagnosis with no real chance for cure. Despite an increasing list of potential salvage therapies, standard-of-care for these patients has not changed in over a decade. Immunotherapy has been seen as an exciting option, with the potential to offer specific and long lasting tumor clearance. The "gold standard" in immunotherapy has been the development of a tumor-specific CD8 T cell response to potentiate tumor clearance and immunological memory. While many advances have been made in the field of immunotherapy, few therapies have seen true success. Many of the same principles used to develop immunotherapy in tumors of the peripheral organs have been applied to brain tumor immunotherapy. The immune-specialized nature of the brain should call into question whether this approach is appropriate. Recent results from our own experiments require a rethinking of current dogma. Perhaps a CD8 T cell response is not sufficient for an organ as immunologically unique as the brain. Examination of previously elucidated principles of the brain's immune-specialized status and known immunological preferences should generate discussion and experimentation to address the failure of current therapies. PMID:27472363

  14. Cutting Edge: Resident Memory CD8 T Cells Express High-Affinity TCRs.

    Science.gov (United States)

    Frost, Elizabeth L; Kersh, Anna E; Evavold, Brian D; Lukacher, Aron E

    2015-10-15

    Tissue-resident memory T (TRM) cells serve as vanguards of antimicrobial host defense in nonlymphoid tissues, particularly at barrier epithelia and in organs with nonrenewable cell types (e.g., brain). In this study, we asked whether an augmented ability to sense Ag complemented their role as early alarms of pathogen invasion. Using mouse polyomavirus, we show that brain-resident mouse polyomavirus-specific CD8 T cells, unlike memory cells in the spleen, progressively increase binding to MHC class I tetramers and CD8 coreceptor expression. Using the two-dimensional micropipette adhesion-frequency assay, we show that TRM cells in brain, as well as in kidney, express TCRs with up to 20-fold higher affinity than do splenic memory T cells, whereas effector cells express TCRs of similar high affinity in all organs. Together, these data demonstrate that TRM cells retain high TCR affinity, which endows them with the high Ag sensitivity needed for front-line defense against infectious agents. PMID:26371252

  15. Proliferation of CD8-positive T cells in blood vessels of rat renal allografts.

    Science.gov (United States)

    Grau, V; Fuchs-Moll, G; Wilker, S; Weimer, R; Padberg, W

    2011-09-01

    It is still disputed in which anatomical compartments of allograft recipients T-cells proliferate. After experimental renal transplantation, host monocytes and lymphocytes accumulate in the lumina of graft blood vessels. In this study, we test the hypothesis that T lymphocytes proliferate in the vascular bed of the graft. Kidneys were transplanted in the Dark Agouti to Lewis rat strain combination, an established experimental model for acute rejection. Isogeneic transplantation was performed as a control. Cells in the S-phase of mitosis were detected in situ three days posttransplantation by pulse-labeling with BrdU and by immunohistochemical detection of the proliferating cell nuclear antigen (PCNA). More than 20% of all T-cells in the lumina of allograft blood vessels incorporated BrdU and approximately 30% of them expressed PCNA. In the blood vessels of isografts as well as in other organs of allograft recipients, only few BrdU(+) cells were detected. A majority of the BrdU(+) cells in graft blood vessels expressed CD8. In conclusion, we demonstrate that CD8(+) T lymphocytes proliferate in the lumina of the blood vessels of renal allografts during the onset of acute rejection.

  16. Reduced interleukin-4 receptor α expression on CD8+ T cells correlates with higher quality anti-viral immunity.

    Directory of Open Access Journals (Sweden)

    Danushka K Wijesundara

    Full Text Available With the hope of understanding how interleukin (IL-4 and IL-13 modulated quality of anti-viral CD8(+ T cells, we evaluated the expression of receptors for these cytokines following a range of viral infections (e.g. pox viruses and influenza virus. Results clearly indicated that unlike other IL-4/IL-13 receptor subunits, IL-4 receptor α (IL-4Rα was significantly down-regulated on anti-viral CD8(+ T cells in a cognate antigen dependent manner. The infection of gene knockout mice and wild-type (WT mice with vaccinia virus (VV or VV expressing IL-4 confirmed that IL-4, IL-13 and signal transducer and activator of transcription 6 (STAT6 were required to increase IL-4Rα expression on CD8(+ T cells, but not interferon (IFN-γ. STAT6 dependent elevation of IL-4Rα expression on CD8(+ T cells was a feature of poor quality anti-viral CD8(+ T cell immunity as measured by the production of IFN-γ and tumor necrosis factor α (TNF-α in response to VV antigen stimulation in vitro. We propose that down-regulation of IL-4Rα, but not the other IL-4/IL-13 receptor subunits, is a mechanism by which CD8(+ T cells reduce responsiveness to IL-4 and IL-13. This can improve the quality of anti-viral CD8(+ T cell immunity. Our findings have important implications in understanding anti-viral CD8(+ T cell immunity and designing effective vaccines against chronic viral infections.

  17. Association between Nef-specific CD8 T-cell responses and disease progression in HIV-1 subtype B infection

    Institute of Scientific and Technical Information of China (English)

    JIAO Yang; LI Tai-sheng; XIE Jing; HAN Yang; QIU Zhi-feng; ZUO Ling-yan; Thomas Mourez; WANG Ai-xia

    2006-01-01

    Background The correlation between HIV-1 Nef-specific CD8 T-cell responses and markers of HIV-1 disease progression still remains unclear. This study analysed and compared the role of HIV-1 Nef-specific CD8 T-cell responses in patients with different disease status.Methods Two groups of patients with HIV-1 subtype B infection were selected according to CD4 count and clinical manifestations: long-term nonprogresssors (LTNPs, n = 20) and advanced progressors (Aps, CD4 count <500 cells/μ1, n = 34). Nef-specific CD8 T-cell responses were studied by interferon- γ ELISpot assay against 3 pools of HIV-Nef peptides.Results Nef-specific CD8 T-cell responses did not correlate with viral load or CD4 count in all patients and no significant differences were found in the magnitude of Nef-specific CD8 T-cell responses between groups LTNPs and Aps (670 SFC/106 peripheral blood mononuclear cells vs 1107 SFC/106 peripheral blood mononuclear cells,P = 0.255). Further comparisons showed that there were also no significant correlations observed in group LTNPs,but Nef-specific CD8 T cells correlated negatively with viral load (r = -0.397, P = 0.020) and positively with CD4 count (r = 0.364, P = 0.034) in group Aps.Conclusion These data suggest that different correlation patterns between Nef-specific CD8 T-cell responses and disease progression exist in LTNPs and Aps. Although a negative association was observed with concurrent plasma HIV RNA in Aps, Nef-specific CD8 T-cell responses might fail to play a protective role in different stages of HIV- 1 infection.

  18. Autoreactive effector/memory CD4+ and CD8+ T cells infiltrating grafted and endogenous islets in diabetic NOD mice exhibit similar T cell receptor usage.

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    Ramiro Diz

    Full Text Available Islet transplantation provides a "cure" for type 1 diabetes but is limited in part by recurrent autoimmunity mediated by β cell-specific CD4(+ and CD8(+ T cells. Insight into the T cell receptor (TCR repertoire of effector T cells driving recurrent autoimmunity would aid the development of immunotherapies to prevent islet graft rejection. Accordingly, we used a multi-parameter flow cytometry strategy to assess the TCR variable β (Vβ chain repertoires of T cell subsets involved in autoimmune-mediated rejection of islet grafts in diabetic NOD mouse recipients. Naïve CD4(+ and CD8(+ T cells exhibited a diverse TCR repertoire, which was similar in all tissues examined in NOD recipients including the pancreas and islet grafts. On the other hand, the effector/memory CD8(+ T cell repertoire in the islet graft was dominated by one to four TCR Vβ chains, and specific TCR Vβ chain usage varied from recipient to recipient. Similarly, islet graft- infiltrating effector/memory CD4(+ T cells expressed a limited number of prevalent TCR Vβ chains, although generally TCR repertoire diversity was increased compared to effector/memory CD8(+ T cells. Strikingly, the majority of NOD recipients showed an increase in TCR Vβ12-bearing effector/memory CD4(+ T cells in the islet graft, most of which were proliferating, indicating clonal expansion. Importantly, TCR Vβ usage by effector/memory CD4(+ and CD8(+ T cells infiltrating the islet graft exhibited greater similarity to the repertoire found in the pancreas as opposed to the draining renal lymph node, pancreatic lymph node, or spleen. Together these results demonstrate that effector/memory CD4(+ and CD8(+ T cells mediating autoimmune rejection of islet grafts are characterized by restricted TCR Vβ chain usage, and are similar to T cells that drive destruction of the endogenous islets.

  19. Memory-Like CD8+ T Cells Generated during Homeostatic Proliferation Defer to Antigen-Experienced Memory Cells1

    OpenAIRE

    Cheung, Kitty P.; Yang, Edward; Goldrath, Ananda W

    2009-01-01

    Naive T cells proliferate in response to lymphopenia and acquire the phenotypic and functional qualities of memory T cells, providing enhanced protection against infection. How well memory-like T cells generated during lymphopenia-induced homeostatic proliferation (HP)-memory differentiate into secondary memory cells and compete with Ag-experienced true-memory cells is unknown. We found that CD8+ HP-memory T cells generated robust responses upon infection and produced a secondary memory popul...

  20. Course and Clinical Significance of CD8+ T-Cell Counts in a Large Cohort of HIV-Infected Individuals

    DEFF Research Database (Denmark)

    Helleberg, Marie; Kronborg, Gitte; Ullum, Henrik;

    2015-01-01

    received care in Copenhagen during 1995-2012. Reference values were obtained from 1230 persons from the background population. Mortality rate ratios were estimated by Poisson regression. RESULTS: CD8(+) T-cell counts were elevated during untreated HIV infection and remained elevated through 10 years of c......OBJECTIVES: To examine trajectories of CD8(+) T-cell counts before and after combination antiretroviral therapy (cART) in human immunodeficiency virus (HIV)-infected individuals and associations with mortality. METHODS: CD8(+) T-cell counts were measured in 3882 HIV-infected individuals who......ART. A slight drop of 130 cells/µL (interquartile range, -160 to 410 cells/μL) in the median CD8(+) T-cell count was observed after cART initiation. CD8(+) T-cell counts stabilized at approximately 900 cells/µL (95th percentile of the background population, 835 cells/µL). Markedly elevated CD8(+) T-cell counts...

  1. MicroRNA-155 is required for effector CD8+ T cell responses to virus infection and cancer

    Science.gov (United States)

    DUDDA, Jan C.; SALAUN, Bruno; JI, Yun; PALMER, Douglas C.; Monnot, Gwennaelle C.; MERCK, Estelle; BOUDOUSQUIE, Caroline; UTZSCHNEIDER, Daniel T.; ESCOBAR, Thelma M.; PERRET, Rachel; MULJO, Stefan A.; HEBEISEN, Michael; RUFER, Nathalie; ZEHN, Dietmar; DONDA, Alena; RESTIFO, Nicholas P.; HELD, Werner; GATTINONI, Luca; ROMERO, Pedro

    2013-01-01

    SUMMARY MicroRNAs regulate the function of several immune cells but their role in promoting CD8+ T-cell immunity remains unknown. Here we report that miR-155 is required for CD8+ T-cell responses to both virus and cancer. In the absence of miR-155, accumulation of effector CD8+ T cells was severely reduced during acute and chronic viral infections and control of virus replication was impaired. Similarly, Mir155-/- CD8+ T cells were in effective at controlling tumor growth, whereas miR-155 overexpression enhanced the antitumor response. miR-155 deficiency resulted in accumulation of SOCS-1 causing defective cytokine signaling through STAT5. Consistently, enforced expression of SOCS-1 in CD8+ T cells phenocopied the miR-155 deficiency, whereas SOCS-1 silencing augmented tumor destruction. These findings identify miR-155 and its target SOCS-1 as key regulators of effector CD8+ T cells that can be modulated to potentiate immunotherapies for infectious diseases and cancer. PMID:23601686

  2. A novel immunodominant CD8+ T cell response restricted by a common HLA-C allele targets a conserved region of Gag HIV-1 clade CRF01_AE infected Thais.

    Directory of Open Access Journals (Sweden)

    Supranee Buranapraditkun

    Full Text Available BACKGROUND: CD8+ T cell responses play an important role in the control of HIV-1. The extensive sequence diversity of HIV-1 represents a critical hurdle to developing an effective HIV-1 vaccine, and it is likely that regional-specific vaccine strains will be required to overcome the diversity of the different HIV-1 clades distributed world-wide. Unfortunately, little is known about the CD8+ T cell responses against CRF01_AE, which is responsible for the majority of infections in Southeast Asia. METHODOLOGY/PRINCIPAL FINDINGS: To identify dominant CD8+ T cell responses recognized in HIV-1 clade CRF01_AE infected subjects we drew upon data from an immunological screen of 100 HIV-1 clade CRF01_AE infected subjects using IFN-gamma ELISpot to characterize a novel immunodominant CD8+ T cell response in HIV-1 Gag restricted by HLA-Cw*0102 (p24, (277YSPVSILDI(285, YI9. Over 75% of Cw*0102+ve subjects targeted this epitope, representing the strongest response in more than a third of these individuals. This novel CD8 epitope was located in a highly conserved region of HIV-1 Gag known to contain immunodominant CD8 epitopes, which are restricted by HLA-B*57 and -B*27 in clade B infection. Nonetheless, viral escape in this epitope was frequently observed in Cw*0102+ve subjects, suggestive of strong selection pressure being exerted by this common CD8+ T cell response. CONCLUSIONS/SIGNIFICANCE: As HLA-Cw*0102 is frequently expressed in the Thai population (allelic frequency of 16.8%, this immunodominant Cw*0102-restricted Gag epitope may represent an attractive candidate for vaccines specific to CRF01_AE and may help facilitate further studies of immunopathogenesis in this understudied HIV-1 clade.

  3. miRNA profiling of naive, effector and memory CD8 T cells.

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    Haoquan Wu

    Full Text Available microRNAs have recently emerged as master regulators of gene expression during development and cell differentiation. Although profound changes in gene expression also occur during antigen-induced T cell differentiation, the role of miRNAs in the process is not known. We compared the miRNA expression profiles between antigen-specific naïve, effector and memory CD8+ T cells using 3 different methods--small RNA cloning, miRNA microarray analysis and real-time PCR. Although many miRNAs were expressed in all the T cell subsets, the frequency of 7 miRNAs (miR-16, miR-21, miR-142-3p, miR-142-5p, miR-150, miR-15b and let-7f alone accounted for approximately 60% of all miRNAs, and their expression was several fold higher than the other expressed miRNAs. Global downregulation of miRNAs (including 6/7 dominantly expressed miRNAs was observed in effector T cells compared to naïve cells and the miRNA expression levels tended to come back up in memory T cells. However, a few miRNAs, notably miR-21 were higher in effector and memory T cells compared to naïve T cells. These results suggest that concomitant with profound changes in gene expression, miRNA profile also changes dynamically during T cell differentiation. Sequence analysis of the cloned mature miRNAs revealed an extensive degree of end polymorphism. While 3'end polymorphisms dominated, heterogeneity at both ends, resembling drosha/dicer processing shift was also seen in miR-142, suggesting a possible novel mechanism to generate new miRNA and/or to diversify miRNA target selection. Overall, our results suggest that dynamic changes in the expression of miRNAs may be important for the regulation of gene expression during antigen-induced T cell differentiation. Our study also suggests possible novel mechanisms for miRNA biogenesis and function.

  4. TCR affinity for thymoproteasome-dependent positively selecting peptides conditions antigen responsiveness in CD8(+) T cells.

    Science.gov (United States)

    Takada, Kensuke; Van Laethem, Francois; Xing, Yan; Akane, Kazuyuki; Suzuki, Haruhiko; Murata, Shigeo; Tanaka, Keiji; Jameson, Stephen C; Singer, Alfred; Takahama, Yousuke

    2015-10-01

    In the thymus, low-affinity T cell antigen receptor (TCR) engagement facilitates positive selection of a useful T cell repertoire. Here we report that TCR responsiveness of mature CD8(+) T cells is fine tuned by their affinity for positively selecting peptides in the thymus and that optimal TCR responsiveness requires positive selection on major histocompatibility complex class I-associated peptides produced by the thymoproteasome, which is specifically expressed in the thymic cortical epithelium. Thymoproteasome-independent positive selection of monoclonal CD8(+) T cells results in aberrant TCR responsiveness, homeostatic maintenance and immune responses to infection. These results demonstrate a novel aspect of positive selection, in which TCR affinity for positively selecting peptides produced by thymic epithelium determines the subsequent antigen responsiveness of mature CD8(+) T cells in the periphery.

  5. Human MAIT and CD8αα cells develop from a pool of type-17 precommitted CD8+ T cells

    OpenAIRE

    Walker, Lucy J.; Kang, Yu-Hoi; Smith, Matthew O.; Tharmalingham, Hannah; Ramamurthy, Narayan; Fleming, Vicki M.; Sahgal, Natasha; Leslie, Alistair; Oo, Ye; Geremia, Alessandra; Scriba, Thomas J.; Hanekom, Willem A; Lauer, Georg M.; Lantz, Olivier; Adams, David H

    2012-01-01

    Human mucosal associated invariant T (MAIT) CD8+ and Tc17 cells are important tissue-homing cell populations, characterized by high expression of CD161 (++) and type-17 differentiation, but their origins and relationships remain poorly defined. By transcriptional and functional analyses, we demonstrate that a pool of polyclonal, precommitted type-17 CD161++CD8αβ+ T cells exist in cord blood, from which a prominent MAIT cell (TCR Vα7.2+) population emerges post-natally. During this expansion, ...

  6. Engagement of NKG2D on bystander memory CD8 T cells promotes increased immunopathology following Leishmania major infection.

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    Erika J Crosby

    2014-02-01

    Full Text Available One of the hallmarks of adaptive immunity is the development of a long-term pathogen specific memory response. While persistent memory T cells certainly impact the immune response during a secondary challenge, their role in unrelated infections is less clear. To address this issue, we utilized lymphocytic choriomeningitis virus (LCMV and Listeria monocytogenes immune mice to investigate whether bystander memory T cells influence Leishmania major infection. Despite similar parasite burdens, LCMV and Listeria immune mice exhibited a significant increase in leishmanial lesion size compared to mice infected with L. major alone. This increased lesion size was due to a severe inflammatory response, consisting not only of monocytes and neutrophils, but also significantly more CD8 T cells. Many of the CD8 T cells were LCMV specific and expressed gzmB and NKG2D, but unexpectedly expressed very little IFN-γ. Moreover, if CD8 T cells were depleted in LCMV immune mice prior to challenge with L. major, the increase in lesion size was lost. Strikingly, treating with NKG2D blocking antibodies abrogated the increased immunopathology observed in LCMV immune mice, showing that NKG2D engagement on LCMV specific memory CD8 T cells was required for the observed phenotype. These results indicate that bystander memory CD8 T cells can participate in an unrelated immune response and induce immunopathology through an NKG2D dependent mechanism without providing increased protection.

  7. Defect of CD8+ Memory T Cells Developed in Absence of IL-12 Priming for Secondary Expansion

    Institute of Scientific and Technical Information of China (English)

    Zhenmin Ye; Shulin Xu; Terence Moyana; Jicheng Yang; Jim Xiang

    2008-01-01

    IL-12 priming plays an important role in stimulation of CD8+ effector T cells and development of CD8+ memory T (Tm) cells. However, the functional alteration of CD8+ Tm cells developed in the absence of IL-12 priming is elusive.In this study, we investigated the capacity of secondary expansion of CD8+ Tm cells developed from transgenic OT I CD8+ T cells. The latter cells were in vitro and in vivo stimulated by ovalbumin (OVA)-puised dendritic cells [DCOVA and (IL-12-/-)DCOVA] derived from wild-type C57BL/6 and IL-12 gene knockout mice, respectively. We demonstrated that IL-12 priming is important not only in CD8+ T cell clonal expansion, but also in generation of CD8+ Tm cells with the capacity of secondary expansion upon antigen re-encounter. However, IL-12 signaling is not involved in CD8+ Tm cell survival and recall responses. Therefore, this study provides useful information for vaccine design and development.

  8. T cell epitope-based allergy vaccines.

    Science.gov (United States)

    Larché, Mark

    2011-01-01

    Specific immunotherapy (SIT) with extracts containing intact allergen molecules is clinically efficacious, but associated with frequent adverse events related to the allergic sensitization of the patient. As a result, treatment is initiated in an incremental dose fashion which ultimately achieves a plateau (maintenance dose) that may be continued for several years. Reduction of allergic adverse events may allow safer and more rapid treatment Thus, many groups have developed and evaluated strategies to reduce allergenicity whilst maintaining immunogenicity, the latter being required to achieve specific modulation of the immune response. Peptide immunotherapy can be used to target T and/or B cells in an antigen-specific manner. To date, only approaches that target T cells have been clinically evaluated. Short, synthetic peptides representing immunodominant T cell epitopes of major allergens are able to modulate allergen-specific T cell responses in the absence of IgE cross linking and activation of effector cells. Here we review clinical and mechanistic studies associated with peptide immunotherapy targeting allergy to cats or to bee venom. 

  9. Characterization of CD8+ T-Cell Responses in the Peripheral Blood and Skin Injection Sites of Melanoma Patients Treated with mRNA Electroporated Autologous Dendritic Cells (TriMixDC-MEL

    Directory of Open Access Journals (Sweden)

    Daphné Benteyn

    2013-01-01

    Full Text Available Treatment of melanoma patients with mRNA electroporated dendritic cells (TriMixDC-MEL stimulates T-cell responses against the presented tumor-associated antigens (TAAs. In the current clinical trials, melanoma patients with systemic metastases are treated, requiring priming and/or expansion of preexisting TAA-specific T cells that are able to migrate to both the skin and internal organs. We monitored the presence of TAA-specific CD8+ T cells infiltrating the skin at sites of intradermal TriMixDC-MEL injection (SKILs and within the circulation of melanoma patients treated in two clinical trials. In 10 out of fourteen (71% patients screened, CD8+ T cells recognizing any of the four TAA presented by TriMixDC-MEL cellular vaccine were found in both compartments. In total, 30 TAA-specific T-cell responses were detected among the SKILs and 29 among peripheral blood T cells, of which 24 in common. A detailed characterization of the antigen specificity of CD8+ T-cell populations in four patients indicates that the majority of the epitopes detected were only recognized by CD8+ T cells derived from either skin biopsies or peripheral blood, indicating that some compartmentalization occurs after TriMix-DC therapy. To conclude, functional TAA-specific CD8+ T cells distribute both to the skin and peripheral blood of patients after TriMixDC-MEL therapy.

  10. Characterization of Immunodominant BK Polyomavirus 9mer Epitope T Cell Responses

    Science.gov (United States)

    Cioni, M.; Leboeuf, C.; Comoli, P.; Ginevri, F.

    2016-01-01

    Uncontrolled BK polyomavirus (BKPyV) replication in kidney transplant recipients (KTRs) causes polyomavirus‐associated nephropathy and allograft loss. Reducing immunosuppression is associated with clearing viremia and nephropathy and increasing BKPyV‐specific T cell responses in most patients; however, current immunoassays have limited sensitivity, target mostly CD4+ T cells, and largely fail to predict onset and clearance of BKPyV replication. To characterize BKPyV‐specific CD8+ T cells, bioinformatics were used to predict 9mer epitopes in the early viral gene region (EVGR) presented by 14 common HLAs in Europe and North America. Thirty‐nine EVGR epitopes were experimentally confirmed by interferon‐γ enzyme‐linked immunospot assays in at least 30% of BKPyV IgG–seropositive healthy participants. Most 9mers clustered in domains, and some were presented by more than one HLA class I, as typically seen for immunodominant epitopes. Specific T cell binding using MHC class I streptamers was demonstrated for 21 of 39 (54%) epitopes. In a prospective cohort of 118 pediatric KTRs, 19 patients protected or recovering from BKPyV viremia were experimentally tested, and 13 epitopes were validated. Single HLA mismatches were not associated with viremia, suggesting that failing immune control likely involves multiple factors including maintenance immunosuppression. Combining BKPyV load and T cell assays using immunodominant epitopes may help in evaluating risk and reducing immunosuppression and may lead to safe adoptive T cell transfer. PMID:26663765

  11. Viral sequestration of antigen subverts cross presentation to CD8(+ T cells.

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    Eric F Tewalt

    2009-05-01

    Full Text Available Virus-specific CD8(+ T cells (T(CD8+ are initially triggered by peptide-MHC Class I complexes on the surface of professional antigen presenting cells (pAPC. Peptide-MHC complexes are produced by two spatially distinct pathways during virus infection. Endogenous antigens synthesized within virus-infected pAPC are presented via the direct-presentation pathway. Many viruses have developed strategies to subvert direct presentation. When direct presentation is blocked, the cross-presentation pathway, in which antigen is transferred from virus-infected cells to uninfected pAPC, is thought to compensate and allow the generation of effector T(CD8+. Direct presentation of vaccinia virus (VACV antigens driven by late promoters does not occur, as an abortive infection of pAPC prevents production of these late antigens. This lack of direct presentation results in a greatly diminished or ablated T(CD8+ response to late antigens. We demonstrate that late poxvirus antigens do not enter the cross-presentation pathway, even when identical antigens driven by early promoters access this pathway efficiently. The mechanism mediating this novel means of viral modulation of antigen presentation involves the sequestration of late antigens within virus factories. Early antigens and cellular antigens are cross-presented from virus-infected cells, as are late antigens that are targeted to compartments outside of the virus factories. This virus-mediated blockade specifically targets the cross-presentation pathway, since late antigen that is not cross-presented efficiently enters the MHC Class II presentation pathway. These data are the first to describe an evasion mechanism employed by pathogens to prevent entry into the cross-presentation pathway. In the absence of direct presentation, this evasion mechanism leads to a complete ablation of the T(CD8+ response and a potential replicative advantage for the virus. Such mechanisms of viral modulation of antigen presentation

  12. Effector and Central Memory Poly-functional CD4+ and CD8+ T cells are Boosted upon ZOSTAVAX® Vaccination

    Directory of Open Access Journals (Sweden)

    Kalpit A Vora

    2015-10-01

    Full Text Available ZOSTAVAX® is a live attenuated varicella-zoster virus (VZV vaccine that is licensed for the protection of individuals ≥ 50 years against shingles, and its most common complication, post-herpetic neuralgia. While IFN responses increase upon vaccination, the quality of the T cell response has not been elucidated. By using polychromatic flow cytometry, we characterized the breadth, magnitude, and quality of ex vivo CD4+ and CD8+ T cell responses induced 3 – 4 weeks after ZOSTAVAX vaccination of healthy adults. We show, for the first time that the highest frequencies of VZV-specific CD4+ T cells were poly-functional CD154+IFNγ+IL-2+TNFα+ cells, which were boosted upon vaccination. The CD4+ T cells were broadly reactive to several VZV proteins, with IE63 ranking the highest amongst them in the fold-rise of poly-functional cells, followed by IE62, gB, ORF9, and gE. We identified a novel poly-functional ORF9-specific CD8+ T cell population in 62% of the subjects, and these were boosted upon vaccination. Poly-functional CD4+ and CD8+ T cells produced significantly higher levels of IFNγ, IL-2, and TNFα compared to mono-functional cells. After vaccination, a boost in the expression of IFN by poly-functional IE63-and ORF9-specific CD4+ T cells, and IFNγ, IL-2, and TNFα by ORF9-specific poly-functional CD8+ T cells was observed. Responding poly-functional T cells exhibited both effector (CCR7−CD45RA−CD45RO+, and central (CCR7+CD45RA−CD45RO+ memory phenotypes, which expressed comparable levels of cytokines. Altogether, our studies demonstrate that a boost in memory poly-functional CD4+ T cells, and ORF9-specific CD8+ T cells may contribute towards ZOSTAVAX efficacy.

  13. Multiscale Modeling of the Early CD8 T-Cell Immune Response in Lymph Nodes: An Integrative Study

    Directory of Open Access Journals (Sweden)

    Sotiris A. Prokopiou

    2014-09-01

    Full Text Available CD8 T-cells are critical  in controlling infection by intracellular  pathogens. Upon encountering antigen presenting cells, T-cell receptor activation promotes the differentiation of naïve CD8 T-cells into strongly proliferating  activated and effector stages. We propose a 2D-multiscale computational model to study the maturation of CD8 T-cells in a lymph node controlled by their molecular profile. A novel molecular pathway is presented and converted into an ordinary differential  equation model, coupled with a cellular Potts model to describe cell-cell interactions. Key molecular  players such as activated IL2 receptor and Tbet levels  control the differentiation  from naïve into activated and effector stages, respectively,  while caspases and Fas-Fas ligand interactions control cell apoptosis.  Coupling  this molecular model to the cellular scale successfully  reproduces  qualitatively the evolution of total CD8 T-cell counts observed in mice lymph node, between Day 3 and 5.5 post-infection. Furthermore, this model allows us to make testable predictions  of the evolution of the different CD8 T-cell stages.

  14. Programming tumor-reactive effector memory CD8+ T cells in vitro obviates the requirement for in vivo vaccination

    OpenAIRE

    Klebanoff, Christopher A.; Yu, Zhiya; Hwang, Leroy N.; Douglas C Palmer; Gattinoni, Luca; Restifo, Nicholas P

    2009-01-01

    Naive and memory CD8+ T cells can undergo programmed activation and expansion in response to a short T-cell receptor stimulus, but the extent to which in vitro programming can qualitatively substitute for an in vivo antigen stimulation remains unknown. We show that self-/tumor-reactive effector memory CD8+ T cells (TEM) programmed in vitro either with peptide-pulsed antigen-presenting cells or plate-bound anti-CD3/anti-CD28 embark on a highly stereotyped response of in vivo clonal expansion a...

  15. Ex vivo restimulation of human PBMC expands a CD3+CD4-CD8- γδ+ T cell population that can confound the evaluation of CD4 and CD8 T cell responses to vaccination.

    Science.gov (United States)

    Sedgmen, B J; Papalia, L; Wang, L; Dyson, A R; McCallum, H A; Simson, C M; Pearse, M J; Maraskovsky, E; Hung, D; Eomois, P P; Hartel, G; Barnden, M J; Rockman, S P

    2013-01-01

    The measurement of vaccine-induced humoral and CD4(+) and CD8(+) cellular immune responses represents an important correlate of vaccine efficacy. Accurate and reliable assays evaluating such responses are therefore critical during the clinical development phase of vaccines. T cells play a pivotal role both in coordinating the adaptive and innate immune responses and as effectors. During the assessment of cell-mediated immunity (CMI) in subjects participating in a large-scale influenza vaccine trial, we identified the expansion of an IFN-γ-producing CD3(+)CD4(-)CD8(-) γδ (+) T cell population in the peripheral blood of 90/610 (15%) healthy subjects. The appearance of CD3(+)CD4(-)CD8(-) γδ (+) T cells in the blood of subjects was transient and found to be independent of the study cohort, vaccine group, subject gender and ethnicity, and ex vivo restimulation conditions. Although the function of this population and relevance to vaccination are unclear, their inclusion in the total vaccine-specific T-cell response has the potential to confound data interpretation. It is thus recommended that when evaluating the induction of IFN-γ-producing CD4(+) and CD8(+) immune responses following vaccination, the CD3(+)CD4(-)CD8(-) γδ (+) T cells are either excluded or separately enumerated from the overall frequency determination. PMID:24066003

  16. Ex Vivo Restimulation of Human PBMC Expands a CD3+CD4−CD8−γδ+ T Cell Population That Can Confound the Evaluation of CD4 and CD8 T Cell Responses to Vaccination

    Science.gov (United States)

    Sedgmen, B. J.; Papalia, L.; Wang, L.; Dyson, A. R.; McCallum, H. A.; Simson, C. M.; Pearse, M. J.; Maraskovsky, E.; Hung, D.; Eomois, P. P.; Hartel, G.; Barnden, M. J.; Rockman, S. P.

    2013-01-01

    The measurement of vaccine-induced humoral and CD4+ and CD8+ cellular immune responses represents an important correlate of vaccine efficacy. Accurate and reliable assays evaluating such responses are therefore critical during the clinical development phase of vaccines. T cells play a pivotal role both in coordinating the adaptive and innate immune responses and as effectors. During the assessment of cell-mediated immunity (CMI) in subjects participating in a large-scale influenza vaccine trial, we identified the expansion of an IFN-γ-producing CD3+CD4−CD8−γδ+ T cell population in the peripheral blood of 90/610 (15%) healthy subjects. The appearance of CD3+CD4−CD8−γδ+ T cells in the blood of subjects was transient and found to be independent of the study cohort, vaccine group, subject gender and ethnicity, and ex vivo restimulation conditions. Although the function of this population and relevance to vaccination are unclear, their inclusion in the total vaccine-specific T-cell response has the potential to confound data interpretation. It is thus recommended that when evaluating the induction of IFN-γ-producing CD4+ and CD8+ immune responses following vaccination, the CD3+CD4−CD8−γδ+ T cells are either excluded or separately enumerated from the overall frequency determination. PMID:24066003

  17. Ex Vivo Restimulation of Human PBMC Expands a CD3+CD4-CD8-γδ+ T Cell Population That Can Confound the Evaluation of CD4 and CD8 T Cell Responses to Vaccination

    Directory of Open Access Journals (Sweden)

    B. J. Sedgmen

    2013-01-01

    Full Text Available The measurement of vaccine-induced humoral and CD4+ and CD8+ cellular immune responses represents an important correlate of vaccine efficacy. Accurate and reliable assays evaluating such responses are therefore critical during the clinical development phase of vaccines. T cells play a pivotal role both in coordinating the adaptive and innate immune responses and as effectors. During the assessment of cell-mediated immunity (CMI in subjects participating in a large-scale influenza vaccine trial, we identified the expansion of an IFN-γ-producing CD3+CD4-CD8-γδ+ T cell population in the peripheral blood of 90/610 (15% healthy subjects. The appearance of CD3+CD4-CD8-γδ+ T cells in the blood of subjects was transient and found to be independent of the study cohort, vaccine group, subject gender and ethnicity, and ex vivo restimulation conditions. Although the function of this population and relevance to vaccination are unclear, their inclusion in the total vaccine-specific T-cell response has the potential to confound data interpretation. It is thus recommended that when evaluating the induction of IFN-γ-producing CD4+ and CD8+ immune responses following vaccination, the CD3+CD4-CD8-γδ+ T cells are either excluded or separately enumerated from the overall frequency determination.

  18. Identification of Cytotoxic T Lymphocyte Epitopes on Swine Viruses: Multi-Epitope Design for Universal T Cell Vaccine

    OpenAIRE

    Liao, Yu-Chieh; Lin, Hsin-Hung; Lin, Chieh-Hua; Chung, Wen-Bin

    2013-01-01

    Classical swine fever (CSF), foot-and-mouth disease (FMD) and porcine reproductive and respiratory syndrome (PRRS) are the primary diseases affecting the pig industry globally. Vaccine induced CD8+ T cell-mediated immune response might be long-lived and cross-serotype and thus deserve further attention. Although large panels of synthetic overlapping peptides spanning the entire length of the polyproteins of a virus facilitate the detection of cytotoxic T lymphocyte (CTL) epitopes, it is an ex...

  19. In vivo proliferation of naïve and memory influenza-specific CD8(+) T cells

    DEFF Research Database (Denmark)

    Flynn, K J; Riberdy, J M; Christensen, Jan Pravsgaard;

    1999-01-01

    days. The greatly expanded population of CD8(+)NPP(+) memory T cells in the lymphoid tissue of secondarily challenged mice declines progressively in mean prevalence over the ensuing 100 days, despite the fact that at least some of these lymphocytes continue to cycle. The recall of cell......The virus-specific CD8(+) T cell response has been analyzed through the development, effector, and recovery phases of primary and secondary influenza pneumonia. Apparently, most, if not all, memory T cells expressing clonotypic receptors that bind a tetrameric complex of influenza nucleoprotein (NP......)(366-374) peptide+H-2D(b) (NPP) are induced to divide during the course of this localized respiratory infection. The replicative phase of the recall response ends about the time that virus can no longer be recovered from the lung, whereas some primary CD8(+)NPP(+) T cells may proliferate for a few more...

  20. Abundance of early functional HIV-specific CD8+ T cells does not predict AIDS-free survival time.

    Directory of Open Access Journals (Sweden)

    Ingrid M M Schellens

    Full Text Available BACKGROUND: T-cell immunity is thought to play an important role in controlling HIV infection, and is a main target for HIV vaccine development. HIV-specific central memory CD8(+ and CD4(+ T cells producing IFNgamma and IL-2 have been associated with control of viremia and are therefore hypothesized to be truly protective and determine subsequent clinical outcome. However, the cause-effect relationship between HIV-specific cellular immunity and disease progression is unknown. We investigated in a large prospective cohort study involving 96 individuals of the Amsterdam Cohort Studies with a known date of seroconversion whether the presence of cytokine-producing HIV-specific CD8(+ T cells early in infection was associated with AIDS-free survival time. METHODS AND FINDINGS: The number and percentage of IFNgamma and IL-2 producing CD8(+ T cells was measured after in vitro stimulation with an overlapping Gag-peptide pool in T cells sampled approximately one year after seroconversion. Kaplan-Meier survival analysis and Cox proportional hazard models showed that frequencies of cytokine-producing Gag-specific CD8(+ T cells (IFNgamma, IL-2 or both shortly after seroconversion were neither associated with time to AIDS nor with the rate of CD4(+ T-cell decline. CONCLUSIONS: These data show that high numbers of functional HIV-specific CD8(+ T cells can be found early in HIV infection, irrespective of subsequent clinical outcome. The fact that both progressors and long-term non-progressors have abundant T cell immunity of the specificity associated with low viral load shortly after seroconversion suggests that the more rapid loss of T cell immunity observed in progressors may be a consequence rather than a cause of disease progression.

  1. Differential activation of proliferation and cytotoxicity in human T-cell lymphotropic virus type I Tax-specific CD8 T cells by an altered peptide ligand.

    OpenAIRE

    Höllsberg, P; Weber, W E; Dangond, F; Batra, V; Sette, A.; Hafler, D A

    1995-01-01

    Human T-cell leukemia virus type I (HTLV-I) gives rise to a neurologic disease known as HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Although the pathogenesis of the disease is unknown, the presence of a remarkably high frequency of Tax-specific, cytotoxic CD8 T cells may suggest a role of these cells in the development of HAM/TSP. Antigen-mediated signaling in a CD8 T-cell clone specific for the Tax(11-19) peptide of HTLV-I was studied using analog peptides substitute...

  2. CD4+ T cell-mediated presentation of non-infectious HIV-1virion antigens to HIV-specific CD8+ T cells

    Institute of Scientific and Technical Information of China (English)

    XU Jian-qing; Franco Lori; Julianna Lisziewicz

    2006-01-01

    Background The mechanism of chronic immune activation and impairment of HIV-specific immune responses during chronic infection is not fully understood. However, it is known that high immune activation leads to more rapid progression to AIDS. We hypothesize that CD4+ T cell-mediated viral antigen presentation contributes to this pathologic immune activation in HIV-infected individuals.Methods HIV-specific T cells, responding to noninfectious HIV-1 virions as antigen, were measured by flow cytometric assays. These experimental conditions reflect the in vivo condition where noninfectious HIV-1 represents more than 99% of the antigens.Results CD4+ T cells purified from HIV-infected individuals were capable of cross presenting exogenous noninfectious HIV-1 virions to HIV-1-specific CD8+ T cells. Cross presentation required the entry of HIV-1 to CD4+ T cells and antigen translocation from endoplasmic reticulum to the Golgi complex. Blocking CD4+mediated activation of HIV-specific CD8+ T cells and redirecting the viral antigens to antigen presenting cells improved HIV-specific T cell responses.Conclusions One possible cause of chronic immune activation and impairment of HIV-1 specific T cell responses is represented by HIV-1 harboring CD4+ T cells cross presenting HIV-1 antigen to activate CD8+ T cells. This new mechanism provides the first evidence that cross presentation of noninfectious HIV-1. Virions play a role in the immunopathogenesis of HIV-1 infection.

  3. Pre-existing vector immunity does not prevent replication deficient adenovirus from inducing efficient CD8 T-cell memory and recall responses.

    Directory of Open Access Journals (Sweden)

    Maria Abildgaard Steffensen

    Full Text Available Adenoviral vectors have shown a great potential for vaccine development due to their inherent ability to induce potent and protective CD8 T-cell responses. However, a critical issue regarding the use of these vectors is the existence of inhibitory immunity against the most commonly used Ad5 vector in a large part of the human population. We have recently developed an improved adenoviral vaccine vector system in which the vector expresses the transgene tethered to the MHC class II associated invariant chain (Ii. To further evaluate the potential of this system, the concept of pre-existing inhibitory immunity to adenoviral vectors was revisited to investigate whether the inhibition previously seen with the Ad5 vector also applied to the optimized vector system. We found this to be the case, and antibodies dominated as the mechanism underlying inhibitory vector immunity. However, presence of CD8 T cells directed against epitopes in the adenoviral vector seemed to correlate with repression of the induced response in re-vaccinated B-cell deficient mice. More importantly, despite a repressed primary effector CD8 T-cell response in Ad5-immune animals subjected to vaccination, memory T cells were generated that provided the foundation for an efficient recall response and protection upon subsequent viral challenge. Furthermore, the transgene specific response could be efficiently boosted by homologous re-immunization. Taken together, these studies indicate that adenoviral vectors can be used to induce efficient CD8 T-cell memory even in individuals with pre-existing vector immunity.

  4. HIV-infected individuals with low CD4/CD8 ratio despite effective antiretroviral therapy exhibit altered T cell subsets, heightened CD8+ T cell activation, and increased risk of non-AIDS morbidity and mortality.

    Directory of Open Access Journals (Sweden)

    Sergio Serrano-Villar

    2014-05-01

    Full Text Available A low CD4/CD8 ratio in elderly HIV-uninfected adults is associated with increased morbidity and mortality. A subset of HIV-infected adults receiving effective antiretroviral therapy (ART fails to normalize this ratio, even after they achieve normal CD4+ T cell counts. The immunologic and clinical characteristics of this clinical phenotype remain undefined. Using data from four distinct clinical cohorts and three clinical trials, we show that a low CD4/CD8 ratio in HIV-infected adults during otherwise effective ART (after CD4 count recovery above 500 cells/mm3 is associated with a number of immunological abnormalities, including a skewed T cell phenotype from naïve toward terminally differentiated CD8+ T cells, higher levels of CD8+ T cell activation (HLADR+CD38+ and senescence (CD28- and CD57+CD28-, and higher kynurenine/tryptophan ratio. Changes in the peripheral CD4/CD8 ratio are also reflective of changes in gut mucosa, but not in lymph nodes. In a longitudinal study, individuals who initiated ART within six months of infection had greater CD4/CD8 ratio increase compared to later initiators (>2 years. After controlling for age, gender, ART duration, nadir and CD4 count, the CD4/CD8 ratio predicted increased risk of morbidity and mortality. Hence, a persistently low CD4/CD8 ratio during otherwise effective ART is associated with increased innate and adaptive immune activation, an immunosenescent phenotype, and higher risk of morbidity/mortality. This ratio may prove useful in monitoring response to ART and could identify a unique subset of individuals needed of novel therapeutic interventions.

  5. Generalized Lévy walks and the role of chemokines in migration of effector CD8+ T cells.

    Science.gov (United States)

    Harris, Tajie H; Banigan, Edward J; Christian, David A; Konradt, Christoph; Tait Wojno, Elia D; Norose, Kazumi; Wilson, Emma H; John, Beena; Weninger, Wolfgang; Luster, Andrew D; Liu, Andrea J; Hunter, Christopher A

    2012-06-28

    Chemokines have a central role in regulating processes essential to the immune function of T cells, such as their migration within lymphoid tissues and targeting of pathogens in sites of inflammation. Here we track T cells using multi-photon microscopy to demonstrate that the chemokine CXCL10 enhances the ability of CD8+ T cells to control the pathogen Toxoplasma gondii in the brains of chronically infected mice. This chemokine boosts T-cell function in two different ways: it maintains the effector T-cell population in the brain and speeds up the average migration speed without changing the nature of the walk statistics. Notably, these statistics are not Brownian; rather, CD8+ T-cell motility in the brain is well described by a generalized Lévy walk. According to our model, this unexpected feature enables T cells to find rare targets with more than an order of magnitude more efficiency than Brownian random walkers. Thus, CD8+ T-cell behaviour is similar to Lévy strategies reported in organisms ranging from mussels to marine predators and monkeys, and CXCL10 aids T cells in shortening the average time taken to find rare targets.

  6. 4-1BB signaling breaks the tolerance of maternal CD8+ T cells that are reactive with alloantigens.

    Directory of Open Access Journals (Sweden)

    Kwang H Kim

    Full Text Available 4-1BB (CD137, TNFRSF9, a member of the activation-induced tumor necrosis factor receptor family, is a powerful T-cell costimulatory molecule. It generally enhances CD8(+ T responses and even breaks the tolerance of CD8(+ T cells in an antigen-specific manner. In the present study we found that it was expressed in the placentas of pregnant mice and that its expression coincided with that of the immunesuppressive enzyme indoleamine 2,3-dioxygenase (IDO. Therefore, we investigated whether 4-1BB signaling is involved in fetal rejection using agonistic anti-4-1BB mAb and 4-1BB-deficient mice. Treatment with agonistic anti-4-1BB mAb markedly increased the rate of rejection of allogeneic but not syngeneic fetuses, and this was primarily dependent on CD8(+ T cells. Complement component 3 (C3 seemed to be the effector molecule because 4-1BB triggering resulting in accumulation of C3 in the placenta, and this accumulation was also reversed by anti-CD8 mAb treatment. These findings demonstrate that 4-1BB triggering breaks the tolerance of CD8(+ T cells to alloantigens in the placenta. Moreover, triggering 4-1BB protected the pregnant mice from Listeria monocytogenes (LM infection, but led to rejection of semi-allogeneic fetuses. Therefore, given the cross-recognition of alloantigen by pathogen-reactive CD8(+ T cells, the true function of 4-1BB may be to reverse the hypo-responsiveness of pathogen-reactive CD8(+ T cells in the placenta in cases of infection, even if that risks losing the fetus.

  7. Priming of CD8 T Cells by Adenoviral Vectors Is Critically Dependent on B7 and Dendritic Cells but Only Partially Dependent on CD28 Ligation on CD8 T Cells

    DEFF Research Database (Denmark)

    Nielsen, Karen N; Steffensen, Maria A; Christensen, Jan P;

    2014-01-01

    expression resulted in a delayed primary response, whereas memory CD8 T cells generated in CD28-deficient mice appeared almost normal in terms of both phenotype and effector cytokine profile, but they exhibited a significantly reduced proliferative capacity upon secondary challenge while retaining immediate...... in vivo effector capabilities: in vivo cytotoxicity and short-term in vivo protective capacity. Overall, our data point to an absolute requirement for professional APCs and the expression of the costimulatory molecules CD80/86 for efficient CD8 T cell priming by adenoviral vectors. Additionally, our......Adenoviral vectors have long been forerunners in the development of effective CD8 T cell-based vaccines; therefore, it is imperative that we understand the factors controlling the induction of robust and long-lasting transgene-specific immune responses by these vectors. In this study, we...

  8. Splenectomy alters distribution and turnover but not numbers or protective capacity of de novo generated memory CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Marie eKim

    2014-11-01

    Full Text Available The spleen is a highly compartmentalized lymphoid organ that allows for efficient antigen presentation and activation of immune responses. Additionally, the spleen itself functions to remove senescent red blood cells, filter bacteria, and sequester platelets. Splenectomy, commonly performed after blunt force trauma or splenomegaly, has been shown to increase risk of certain bacterial and parasitic infections years after removal of the spleen. Although previous studies report defects in memory B cells and IgM titers in splenectomized patients, the effect of splenectomy on CD8 T cell responses and memory CD8 T cell function remains ill defined. Using TCR-transgenic P14 cells, we demonstrate that homeostatic proliferation and representation of pathogen-specific memory CD8 T cells in the blood are enhanced in splenectomized compared to sham surgery mice. Surprisingly, despite the enhanced turnover, splenectomized mice displayed no changes in total memory CD8 T cell numbers nor impaired protection against lethal dose challenge with Listeria monocytogenes. Thus, our data suggest that memory CD8 T cell maintenance and function remain intact in the absence of the spleen.

  9. Dysfunctional memory CD8+ T cells after priming in the absence of the cell cycle regulator E2F4.

    Science.gov (United States)

    Bancos, Simona; Cao, Qingyu; Bowers, William J; Crispe, Ian Nicholas

    2009-01-01

    The transcriptional repressor E2F4 is important for cell cycle exit and terminal differentiation in epithelial cells, neuronal cells and adipocytes but its role in T lymphocytes proliferation and memory formation is not known. Herein, we investigated the function of E2F4 protein for the formation of functional murine memory T cells. Murine transgenic CD8+ T cells were infected in vitro with lentivirus vector expressing a shRNA targeted against E2F4 followed by in vitro stimulation with SIINFEKL antigenic peptide. For in vivo assays, transduced cells were injected into congenic mice which were then infected with HSV-OVA. The primary response, memory formation and secondary stimulation were determined for CD8+ lentivirus transduced cells. In the absence of E2F4 cell cycle repressor, activated CD8+ T cells underwent intensive proliferation in vitro and in vivo. These cells had the ability to differentiate into memory cells in vivo, but they were defective in recall proliferation. We show that transient suppression of E2F4 during CD8+ T cell priming enhances primary proliferation and has a negative effect on secondary stimulation. These findings demonstrate that the cell cycle repressor E2F4 is essential for the formation of functional memory T cells. A decrease in CD8+ T-lymphocyte compartment would diminish our capacity to control viral infections.

  10. CD19 CAR–T cells of defined CD4+:CD8+ composition in adult B cell ALL patients

    Science.gov (United States)

    Turtle, Cameron J.; Hanafi, Laïla-Aïcha; Berger, Carolina; Gooley, Theodore A.; Cherian, Sindhu; Hudecek, Michael; Sommermeyer, Daniel; Melville, Katherine; Pender, Barbara; Budiarto, Tanya M.; Robinson, Emily; Steevens, Natalia N.; Chaney, Colette; Soma, Lorinda; Chen, Xueyan; Li, Daniel; Cao, Jianhong; Heimfeld, Shelly; Jensen, Michael C.; Riddell, Stanley R.; Maloney, David G.

    2016-01-01

    BACKGROUND. T cells that have been modified to express a CD19-specific chimeric antigen receptor (CAR) have antitumor activity in B cell malignancies; however, identification of the factors that determine toxicity and efficacy of these T cells has been challenging in prior studies in which phenotypically heterogeneous CAR–T cell products were prepared from unselected T cells. METHODS. We conducted a clinical trial to evaluate CD19 CAR–T cells that were manufactured from defined CD4+ and CD8+ T cell subsets and administered in a defined CD4+:CD8+ composition to adults with B cell acute lymphoblastic leukemia after lymphodepletion chemotherapy. RESULTS. The defined composition product was remarkably potent, as 27 of 29 patients (93%) achieved BM remission, as determined by flow cytometry. We established that high CAR–T cell doses and tumor burden increase the risks of severe cytokine release syndrome and neurotoxicity. Moreover, we identified serum biomarkers that allow testing of early intervention strategies in patients at the highest risk of toxicity. Risk-stratified CAR–T cell dosing based on BM disease burden decreased toxicity. CD8+ T cell–mediated anti-CAR transgene product immune responses developed after CAR–T cell infusion in some patients, limited CAR–T cell persistence, and increased relapse risk. Addition of fludarabine to the lymphodepletion regimen improved CAR–T cell persistence and disease-free survival. CONCLUSION. Immunotherapy with a CAR–T cell product of defined composition enabled identification of factors that correlated with CAR–T cell expansion, persistence, and toxicity and facilitated design of lymphodepletion and CAR–T cell dosing strategies that mitigated toxicity and improved disease-free survival. TRIAL REGISTRATION. ClinicalTrials.gov NCT01865617. FUNDING. R01-CA136551; Life Science Development Fund; Juno Therapeutics; Bezos Family Foundation. PMID:27111235

  11. NS1 specific CD8+ T-cells with effector function and TRBV11 dominance in a patient with parvovirus B19 associated inflammatory cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Mathias Streitz

    Full Text Available BACKGROUND: Parvovirus B19 (B19V is the most commonly detected virus in endomyocardial biopsies (EMBs from patients with inflammatory cardiomyopathy (DCMi. Despite the importance of T-cells in antiviral defense, little is known about the role of B19V specific T-cells in this entity. METHODOLOGY AND PRINCIPAL FINDINGS: An exceptionally high B19V viral load in EMBs (115,091 viral copies/mug nucleic acids, peripheral blood mononuclear cells (PBMCs and serum was measured in a DCMi patient at initial presentation, suggesting B19V viremia. The B19V viral load in EMBs had decreased substantially 6 and 12 months afterwards, and was not traceable in PBMCs and the serum at these times. Using pools of overlapping peptides spanning the whole B19V proteome, strong CD8(+ T-cell responses were elicited to the 10-amino-acid peptides SALKLAIYKA (19.7% of all CD8(+ cells and QSALKLAIYK (10% and additional weaker responses to GLCPHCINVG (0.71% and LLHTDFEQVM (0.06%. Real-time RT-PCR of IFNgamma secretion-assay-enriched T-cells responding to the peptides, SALKLAIYKA and GLCPHCINVG, revealed a disproportionately high T-cell receptor Vbeta (TRBV 11 expression in this population. Furthermore, dominant expression of type-1 (IFNgamma, IL2, IL27 and T-bet and of cytotoxic T-cell markers (Perforin and Granzyme B was found, whereas gene expression indicating type-2 (IL4, GATA3 and regulatory T-cells (FoxP3 was low. CONCLUSIONS: Our results indicate that B19V Ag-specific CD8(+ T-cells with effector function are involved in B19V associated DCMi. In particular, a dominant role of TRBV11 and type-1/CTL effector cells in the T-cell mediated antiviral immune response is suggested. The persistence of B19V in the endomyocardium is a likely antigen source for the maintenance of CD8(+ T-cell responses to the identified epitopes.

  12. Deficient CD4+ T cell priming and regression of CD8+ T cell functionality in virus-infected mice lacking a normal B cell compartment

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Kauffmann, Susanne Ørding; Thomsen, Allan Randrup

    2003-01-01

    precedes recrudescence of detectable virus, indicating that the T cell defect is not simply a secondary event due to virus buildup resulting from the failure of B(-/-) mice to produce neutralizing Abs. In contrast with CD8(+) T cells, which initially respond almost as in wild-type mice, the priming...... of virus-specific CD4(+) T cells was markedly impaired in B(-/-) mice infected with either virus strain. Thus, our results indicate that B cells play an important role in antiviral immunity not only as Ab producers, but also in promoting an optimal and sustained T cell response. The T cell defects...

  13. High epitope expression levels increase competition between T cells.

    Directory of Open Access Journals (Sweden)

    Almut Scherer

    2006-08-01

    Full Text Available Both theoretical predictions and experimental findings suggest that T cell populations can compete with each other. There is some debate on whether T cells compete for aspecific stimuli, such as access to the surface on antigen-presenting cells (APCs or for specific stimuli, such as their cognate epitope ligand. We have developed an individual-based computer simulation model to study T cell competition. Our model shows that the expression level of foreign epitopes per APC determines whether T cell competition is mainly for specific or aspecific stimuli. Under low epitope expression, competition is mainly for the specific epitope stimuli, and, hence, different epitope-specific T cell populations coexist readily. However, if epitope expression levels are high, aspecific competition becomes more important. Such between-specificity competition can lead to competitive exclusion between different epitope-specific T cell populations. Our model allows us to delineate the circumstances that facilitate coexistence of T cells of different epitope specificity. Understanding mechanisms of T cell coexistence has important practical implications for immune therapies that require a broad immune response.

  14. Human cytomegalovirus microRNA miR-US4-1 inhibits CD8+ T cell response by targeting the aminopeptidase ERAP1

    OpenAIRE

    Kim, Sungchul; Lee, Sanghyun; Shin, Jinwook; Kim, Youngkyun; Evnouchidou, Irini; Kim, Donghyun; Kim, Young-Kook; Kim, Young-Eui; Ahn, Jin-Hyun; Riddell, Stanley R; Stratikos, Efstratios; Kim, V. Narry; Ahn, Kwangseog

    2011-01-01

    The major histocompatibility complex (MHC) class I molecules present peptides on the cell surface by CD8+ T cells, which is critical for killing of virally infected or transformed cells. Precursors of MHC class I-presented peptides are trimmed to mature epitopes by endoplasmic reticulum aminopeptidase 1 (ERAP1). The US2-US11 genomic region of human cytomegalovirus (HCMV) is dispensable for viral replication and harbors 3 microRNAs (miRNAs). We show here the HCMV miR-US4-1 specifically down-re...

  15. Enhanced Th1/Th17 Functions of CD161+ CD8+ T Cells in Mucosal Tissues of Rhesus Macaques.

    Directory of Open Access Journals (Sweden)

    Namita Rout

    Full Text Available Expression of the C-type lectin-like receptor CD161 by human T cells is associated with type-17 responses, which play critical regulatory roles in immunity and inflammation at mucosal sites. However, the functions of CD161-expressing T cells in macaques, the pre-clinical model of several human diseases, remain unknown. This study examined the phenotypic and functional characteristics of CD161+ T cells in peripheral blood, mucosal tissues and lymph nodes of rhesus macaques. Majority of CD161-expressing T cells in peripheral blood and lung/intestinal mucosal tissues of rhesus macaques were found to be CD8+CD4- in phenotype. There was a significant enrichment of CD161+CD8+ T cells in the lungs and colonic mucosa (16.1%±6.6 and 16.8%±5.7 in comparison to peripheral blood (4.2%±1.2 and mesenteric lymph nodes (1.3%±0.8. Regardless of the tissue compartment, CD161+CD8+ T cells mainly comprised of γδ T cells and TCR Vα7.2+ MAIT cells (up to 80%, and displayed Th1 and Th17 cytokine responses to mitogen stimulation. Mucosal CD161+CD8+ T cells were characterized by very high expression of CD69, a recent activation marker that is preferentially expressed on tissue resident cells. Furthermore, lung and colonic mucosal CD161+CD8+ T cells showed enhanced IFN-γ, IL-17, and Perforin production in comparison to those in blood. Thus, macaque CD161+CD8+ T cells represent mucosal tissue-homing innate-like CD8+ T-cell populations with Th1/Th17 type cytokine and cytotoxic effector functions that can potentially enhance the recruitment of adaptive immune cells and control initial pathogen burden/dissemination in tissues. Analysis of their role in early immune responses to mucosal pathogens will be valuable in the design of vaccines and therapeutics.

  16. Activated human neonatal CD8+ T cells are subject to immunomodulation by direct TLR2 or TLR5 stimulation.

    LENUS (Irish Health Repository)

    McCarron, Mark

    2012-02-01

    In conditions of optimal priming, the neonate possesses competency to mount quantitatively adult-like responses. Vaccine formulations containing sufficiently potent adjuvants may overcome the neonate\\'s natural tendency for immunosuppression and provoke a similarly robust immune response. TLR expression on T cells represents the possibility of directly enhancing T cell immunity. We examined the ex vivo responsiveness of highly purified human cord blood-derived CD8(+) T cells to direct TLR ligation by a repertoire of TLR agonists. In concert with TCR stimulation, only Pam(3)Cys (palmitoyl-3-Cys-Ser-(Lys)(4)) and flagellin monomers significantly enhanced proliferation, CD25(+) expression, IL-2, IFN-gamma, TNF-alpha, and intracellular granzyme B expression. TLR2 and TLR5 mRNA was detected in the CD8(+) T cells. Blocking studies confirmed that the increase in IFN-gamma production was by the direct triggering of surface TLR2 or TLR5. The simultaneous exposure of CD8(+) T cells to both TLR agonists had an additive effect on IFN-gamma production. These data suggest that a combination of the two TLR ligands would be a potent T cell adjuvant. This may represent a new approach to TLR agonist-based adjuvant design for future human neonatal vaccination strategies requiring a CD8(+) component.

  17. CD8(+ T cells restrict Yersinia pseudotuberculosis infection: bypass of anti-phagocytosis by targeting antigen-presenting cells.

    Directory of Open Access Journals (Sweden)

    Molly A Bergman

    2009-09-01

    Full Text Available All Yersinia species target and bind to phagocytic cells, but uptake and destruction of bacteria are prevented by injection of anti-phagocytic Yop proteins into the host cell. Here we provide evidence that CD8(+ T cells, which canonically eliminate intracellular pathogens, are important for restricting Yersinia, even though bacteria are primarily found in an extracellular locale during the course of disease. In a model of infection with attenuated Y. pseudotuberculosis, mice deficient for CD8(+ T cells were more susceptible to infection than immunocompetent mice. Although exposure to attenuated Y. pseudotuberculosis generated T(H1-type antibody responses and conferred protection against challenge with fully virulent bacteria, depletion of CD8(+ T cells during challenge severely compromised protective immunity. Strikingly, mice lacking the T cell effector molecule perforin also succumbed to Y. pseudotuberculosis infection. Given that the function of perforin is to kill antigen-presenting cells, we reasoned that cell death marks bacteria-associated host cells for internalization by neighboring phagocytes, thus allowing ingestion and clearance of the attached bacteria. Supportive of this model, cytolytic T cell killing of Y. pseudotuberculosis-associated host cells results in engulfment by neighboring phagocytes of both bacteria and target cells, bypassing anti-phagocytosis. Our findings are consistent with a novel function for cell-mediated immune responses protecting against extracellular pathogens like Yersinia: perforin and CD8(+ T cells are critical for hosts to overcome the anti-phagocytic action of Yops.

  18. Induction of a Cross-Reactive CD8+ T Cell Response following Foot-and-Mouth Disease Virus Vaccination▿

    OpenAIRE

    Guzman, Efrain; Taylor, Geraldine; Charleston, Bryan; Ellis, Shirley A

    2010-01-01

    Foot-and-mouth disease virus (FMDV) causes a highly contagious infection in cloven-hoofed animals. Current inactivated FMDV vaccines generate short-term, serotype-specific protection, mainly through neutralizing antibody. An improved understanding of the mechanisms of protective immunity would aid design of more effective vaccines. We have previously reported the presence of virus-specific CD8+ T cells in FMDV-vaccinated and -infected cattle. In the current study, we aimed to identify CD8+ T ...

  19. Characterization of Liver CD8 T Cell Subsets that are Associated with Protection Against Pre-erythrocytic Plasmodium Parasites.

    Science.gov (United States)

    Zarling, Stasya; Krzych, Urszula

    2015-01-01

    Murine models of malaria, such as Plasmodium berghei (Pb) and Plasmodium yoelii (Py), have been used for decades to identify correlates of protection associated with immunization using radiation-attenuated sporozoites (RAS). To date, RAS is the only known immunization regimen to consistently deliver 100 % sterilizing immunity and is considered the "gold standard" of protection against malaria. The ability to isolate lymphocytes directly from the liver of immune mice has facilitated the identification of correlates of protection at the site of infection. Liver CD8 T cells have been identified as a key factor in mediating protection against challenge with infectious Plasmodium sporozoites. Liver CD3 + CD8 T cells can further be divided into subsets based on the expression of specific surface molecules and the increase of CD8 effector memory (TEM) cells (identified by the phenotype CD44(+)CD62L(-)) has been shown to mediate protection by releasing of IFN-γ while CD8 central memory (TCM) cells (CD44(+)CD62L(+)) are important for maintaining long-term protection.Identification of multiple CD8 T cell subsets present in the liver relies on the ability to detect multiple surface markers simultaneously. Polychromatic flow cytometry affords the user with the ability to distinguish multiple lymphocyte populations as well as subsets defined within each population. In this chapter we present a basic 9-color surface staining panel that can be used to identify CD8 TEM, CD8 TCM, short-lived effector cells (SLECs), and memory precursor cells (MPECs) as well as identify those cells which have recently undergone degranulation (surface expression of CD107a). This panel has been designed to allow for the addition of intracellular staining for IFN-γ on other available channels (such as PE) as is discussed in another chapter for analysis of functional CD8 T cell responses. PMID:26450377

  20. Measurement of HCV-Specific CD8(+) Cytotoxic T-Cell Activities in the Peripheral Blood by Europium Release Assay.

    Science.gov (United States)

    Imawari, M

    1999-01-01

    Peripheral blood mononuclear cells (PBMC) contain NK cells, cytotoxic T-lymphocytes (CTL), helper T-cells, and B-cells that respond to viral infection and act to eliminate the virus from infected individuals. CTLs are not only thought to be a major host defense against viral infection, but are also implicated in the immunopathogenesis. Classical CTLs are CD8(+) and recognize endogenously synthesized and processed antigen in association with a human leukocyte antigen (HLA) class I molecule. The antigens are usually 8-10 amino acids long. HCV-specific CTLs have been demonstrated in the peripheral blood of some of patients with HCV infection by stimulating PBMC with the HCV synthetic peptides (1). The peptides were synthesized as overlapping peptides to encompass a certain region of the HCV antigen (1), on the basis of antigenicity prediction from the amino acid composition of HCV (2), or on the basis of the HLA binding motifs in the HCV antigen (3). Several minimal and optimal epitopes in the HCV antigen and their HLA restriction of recognition by CTLs have been defined. Recently, it has been reported that HCV-specific CTLs may suppress the outgrowth of HCV (4). In this chapter, methods will be discussed that demonstrate HCV-specific CTLs in the peripheral blood of patients with HCV infection. We use nonradioisotope europium (Eu) for assay of CTL activities. PMID:21374383

  1. Broadening the repertoire of melanoma-associated T-cell epitopes

    DEFF Research Database (Denmark)

    Frøsig, Thomas Mørch; Lyngaa, Rikke Birgitte; Met, Özcan;

    2015-01-01

    Immune therapy has provided a significant breakthrough in the treatment of metastatic melanoma. Despite the remarkable clinical efficacy and established involvement of effector CD8 T cells, the knowledge of the exact peptide-MHC complexes recognized by T cells on the tumor cell surface is limited....... Many melanoma-associated T-cell epitopes have been described, but this knowledge remains largely restricted to HLA-A2, and we lack understanding of the T-cell recognition in the context of other HLA molecules. We selected six melanoma-associated antigens (MAGE-A3, NY-ESO-1, gp100, Mart1, tyrosinase......-based enrichment of peripheral blood from 39 melanoma patients and 10 healthy donors. To dissect the T-cell reactivity against this large peptide library, we used combinatorial-encoded MHC multimers and observed the T-cell responses against 17 different peptide-MHC complexes in the patient group and four...

  2. A false expression of CD8 antigens on CD4+ T cells in a routine flow cytometry analysis.

    Directory of Open Access Journals (Sweden)

    Danuta Kowalczyk

    2006-09-01

    Full Text Available The two-colour flow cytometry method applied in a routine enumeration of peripheral blood T lymphocyte subsets reveals that in some patients the entire population of CD4+ lymphocytes seems to express CD8 determinants as well. However, expression of the CD8 antigens on the cell surface is much lower in comparison with typical CD8+ cells. Moreover, in one-colour staining with an anti-CD8 antibody, cells with weak CD8 expression are not observed and only one typical population of CD8+ lymphocytes is seen. Investigating this phenomenon, we showed that after washing patient cells in RPMI before CD4/CD8 staining, the CD4+ T cell population did not show CD8 "co-expression". These results suggest that CD4+ lymphocytes, which seem to co-express CD8 antigen, in fact do not have this antigen on their surface. Moreover, after the addition of patient plasma to healthy donor cells prior to CD4/CD8 staining, a weak CD8 expression on normal CD4+ cells was noticed. Therefore we can assume that the agent(s causing this phenomenon is/are present in the plasma of some patients. Altogether, these observations suggest that this phenomenon is nonspecific and probably results from cross-linking of anti-CD8 mAbs with anti-CD4 mAbs caused by factor(s present in plasma of some patient. However, identification of that/these factor(s requires further research.

  3. Transcriptome Signatures Reveal Rapid Induction of Immune-Responsive Genes in Human Memory CD8(+) T Cells.

    Science.gov (United States)

    Yang, Cheng; Khanniche, Asma; DiSpirito, Joanna R; Ji, Ping; Wang, Shujun; Wang, Ying; Shen, Hao

    2016-01-01

    Memory T cells (TM) play a prominent role in protection and auto-immunity due to their ability to mount a more effective response than naïve T cells (TN). However, the molecular mechanisms underlying enhanced functionality of TM are not well defined, particularly in human TM. We examined the global gene expression profiles of human CD8(+) TN and TM before and after stimulation. There were 1,284, 1,373 and 1,629 differentially expressed genes between TN and TM at 0 hr, 4 hr and 24 hr after stimulation, respectively, with more genes expressed to higher levels in TM. Genes rapidly up-regulated in TN cells were largely involved in nitrogen, nucleoside and amino acid metabolisms. In contrast, those in CD8(+) TM were significantly enriched for immune-response-associated processes, including cytokine production, lymphocyte activation and chemotaxis. Multiple cytokines were rapidly up-regulated in TM cells, including effector cytokines known to be produced by CD8(+) T cells and important for their functions, as well as regulatory cytokines, both pro- and anti-inflammatory, that are not typically produced by CD8(+) T cells. These results provide new insights into molecular mechanisms that contribute to the enhanced functionality of human CD8(+) TM and their prominent role in protection and auto-immunity. PMID:27243788

  4. PD-L1 Expression on Retrovirus-Infected Cells Mediates Immune Escape from CD8+ T Cell Killing

    Science.gov (United States)

    Neff, C. Preston; Gibbert, Kathrin; Dietze, Kirsten K.; Werner, Tanja; Liu, Jia; Chen, Lieping; Lang, Karl S.; Palmer, Brent E.; Dittmer, Ulf; Zelinskyy, Gennadiy

    2015-01-01

    Cytotoxic CD8+ T Lymphocytes (CTL) efficiently control acute virus infections but can become exhausted when a chronic infection develops. Signaling of the inhibitory receptor PD-1 is an important mechanism for the development of virus-specific CD8+ T cell dysfunction. However, it has recently been shown that during the initial phase of infection virus-specific CD8+ T cells express high levels of PD-1, but are fully competent in producing cytokines and killing virus-infected target cells. To better understand the role of the PD-1 signaling pathway in CD8+ T cell cytotoxicity during acute viral infections we analyzed the expression of the ligand on retrovirus-infected cells targeted by CTLs. We observed increased levels of PD-L1 expression after infection of cells with the murine Friend retrovirus (FV) or with HIV. In FV infected mice, virus-specific CTLs efficiently eliminated infected target cells that expressed low levels of PD-L1 or that were deficient for PD-L1 but the population of PD-L1high cells escaped elimination and formed a reservoir for chronic FV replication. Infected cells with high PD-L1 expression mediated a negative feedback on CD8+ T cells and inhibited their expansion and cytotoxic functions. These findings provide evidence for a novel immune escape mechanism during acute retroviral infection based on PD-L1 expression levels on virus infected target cells. PMID:26484769

  5. PD-L1 Expression on Retrovirus-Infected Cells Mediates Immune Escape from CD8+ T Cell Killing.

    Directory of Open Access Journals (Sweden)

    Ilseyar Akhmetzyanova

    2015-10-01

    Full Text Available Cytotoxic CD8+ T Lymphocytes (CTL efficiently control acute virus infections but can become exhausted when a chronic infection develops. Signaling of the inhibitory receptor PD-1 is an important mechanism for the development of virus-specific CD8+ T cell dysfunction. However, it has recently been shown that during the initial phase of infection virus-specific CD8+ T cells express high levels of PD-1, but are fully competent in producing cytokines and killing virus-infected target cells. To better understand the role of the PD-1 signaling pathway in CD8+ T cell cytotoxicity during acute viral infections we analyzed the expression of the ligand on retrovirus-infected cells targeted by CTLs. We observed increased levels of PD-L1 expression after infection of cells with the murine Friend retrovirus (FV or with HIV. In FV infected mice, virus-specific CTLs efficiently eliminated infected target cells that expressed low levels of PD-L1 or that were deficient for PD-L1 but the population of PD-L1high cells escaped elimination and formed a reservoir for chronic FV replication. Infected cells with high PD-L1 expression mediated a negative feedback on CD8+ T cells and inhibited their expansion and cytotoxic functions. These findings provide evidence for a novel immune escape mechanism during acute retroviral infection based on PD-L1 expression levels on virus infected target cells.

  6. Molecular analysis of tumor-promoting CD8+ T cells in two-stage cutaneous chemical carcinogenesis.

    Science.gov (United States)

    Kwong, Bernice Y; Roberts, Scott J; Silberzahn, Tobias; Filler, Renata B; Neustadter, Jason H; Galan, Anjela; Reddy, Swapna; Lin, William M; Ellis, Peter D; Langford, Cordelia F; Hayday, Adrian C; Girardi, Michael

    2010-06-01

    T-pro are tumor-infiltrating TCRalphabeta(+)CD8(+) cells of reduced cytotoxic potential that promote experimental two-stage chemical cutaneous carcinogenesis. Toward understanding their mechanism of action, this study uses whole-genome expression analysis to compare T-pro with systemic CD8(+) T cells from multiple groups of tumor-bearing mice. T-pro show an overt T helper 17-like profile (high retinoic acid-related orphan receptor-(ROR)gammat, IL-17A, IL-17F; low T-bet and eomesodermin), regulatory potential (high FoxP3, IL-10, Tim-3), and transcripts encoding epithelial growth factors (amphiregulin, Gro-1, Gro-2). Tricolor flow cytometry subsequently confirmed the presence of TCRbeta(+) CD8(+) IL-17(+) T cells among tumor-infiltrating lymphocytes (TILs). Moreover, a time-course analysis of independent TIL isolates from papillomas versus carcinomas exposed a clear association of the "T-pro phenotype" with malignant progression. This molecular characterization of T-pro builds a foundation for elucidating the contributions of inflammation to cutaneous carcinogenesis, and may provide useful biomarkers for cancer immunotherapy in which the widely advocated use of tumor-specific CD8(+) cytolytic T cells should perhaps accommodate the cells' potential corruption toward the T-pro phenotype. The data are also likely germane to psoriasis, in which the epidermis may be infiltrated by CD8(+) IL-17-producing T cells.

  7. Tc17, a Unique Subset of CD8 T Cells That Can Protect against Lethal Influenza Challenge1

    OpenAIRE

    Hamada, Hiromasa; de la Luz Garcia-Hernandez, Maria; Reome, Joyce B.; Misra, Sara K.; Strutt, Tara M.; McKinstry, Kai K.; Cooper, Andrea M.; Swain, Susan L.; Dutton, Richard W.

    2009-01-01

    We show here that IL-17-secreting CD4 T (Th)17 and CD8 T (Tc)17 effector cells are found in the lung following primary challenge with influenza A and that blocking Ab to IL-17 increases weight loss and reduces survival. Tc17 effectors can be generated in vitro using naive CD8 T cells from OT-I TCR-transgenic mice. T cell numbers expand 20-fold and a majority secretes IL-17, but little IFN-γ. Many of the IL-17-secreting cells also secrete TNF and some secrete IL-2. Tc17 are negative for granzy...

  8. CCR2+ and CCR5+ CD8+ T cells increase during viral infection and migrate to sites of infection

    DEFF Research Database (Denmark)

    Nansen, A; Marker, O; Bartholdy, C;

    2000-01-01

    expression was dominated by CCR1, CCR2 and CCR5. However, despite a stronger initial chemokine signal in VSV-infected mice, only LCMV-induced T cell-dependent inflammation was found to be associated with substantially increased expression of CCR genes. Virus-activated CD8+ T cells were found to express CCR2...... and CCR5, whereas activated monocytes/macrophages expressed CCR1 in addition to CCR2 and CCR5. Together, these CCR profiles readily account for the CCR profile prominent during CD8+-dependent CNS inflammation....

  9. Rapid selection of escape mutants by the first CD8 T cell responses in acute HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette Tina Marie [Los Alamos National Laboratory

    2008-01-01

    The recent failure of a vaccine that primes T cell responses to control primary HIV-1 infection has raised doubts about the role of CD8+ T cells in early HIV-1 infection. We studied four patients who were identified shortly after HIV-1 infection and before seroconversion. In each patient there was very rapid selection of multiple HIV-1 escape mutants in the transmitted virus by CD8 T cells, including examples of complete fixation of non-synonymous substitutions within 2 weeks. Sequencing by single genome amplification suggested that the high rate of virus replication in acute infection gave a selective advantage to virus molecules that contained simultaneous and gained sequential T cell escape mutations. These observations show that whilst early HIV-1 specific CD8 T cells can act against virus, rapid escape means that these T cell responses are unlikely to benefit the patient and may in part explain why current HIV-1 T cell vaccines may not be protective.

  10. Low Intraprostatic DHT Promotes the Infiltration of CD8+ T Cells in BPH Tissues via Modulation of CCL5 Secretion

    Directory of Open Access Journals (Sweden)

    Yu Fan

    2014-01-01

    Full Text Available Clinical studies suggested thatandrogen might be associated with infiltrating T cells in prostate of benign prostatic hyperplasia (BPH patients, but detail of T-cell subset and mechanism still remained unclear. The present study tested the hypothesis that intraprostatic 5α-dihydrotestosterone (DHT exerts effects on T cells recruitment by BPH epithelial cells. Prostate tissues from 64 cases of BPH patients after transurethral resection of prostate (TURP were divided into 2 groups: (1 no medication history; (2 administration of 5α-reductase type II inhibitor-finasteride 5 mg daily for at least 6 months before surgery. Group 2 presented significantly higher CD8+ T cells infiltration than group 1, but no changes in CD4+ T cells (immunohistochemistry and flow cytometry. In vitro study more CD8+ T cell migrated to the prostate tissue lysates from group 2 and BPH-1 cells in low DHT condition. Transcription of chemokine (C-C motif Ligand 5 (CCL5 mRNA in BPH-1 cells and chemokine (C-C motif receptor 5 (CCR5 mRNA in CD8+ T cells were upregulated in low DHT condition (q-PCR. CCL5 expression was also identified to be higher in group 2 prostate tissues by IHC. This study suggested that intraprostatic DHT may participate in regulating inflammatory response which was induced by human prostatic epithelial cell, via modulating CCL5 secretion.

  11. Inhibitory receptor expression depends more dominantly on differentiation and activation than exhaustion of human CD8 T cells

    Directory of Open Access Journals (Sweden)

    Amandine eLegat

    2013-12-01

    Full Text Available Under conditions of chronic antigen stimulation, such as persistent viral infection and cancer, CD8 T cells may diminish effector function, which has been termed exhaustion. Expression of inhibitory Receptors (iRs is often regarded as a hallmark of exhaustion. Here we studied the expression of eight different iRs by CD8 T cells of healthy humans, including CTLA-4, PD1, TIM3, LAG3, 2B4, BTLA, CD160 and KLRG-1. We show that many iRs are expressed upon activation, and with progressive differentiation to effector cells, even in absence of long-term (chronic antigenic stimulation. In particular, we evaluated the direct relationship between iR expression and functionality in CD8 T cells by using anti-CD3 and anti-CD28 stimulation to stimulate all cells and differentiation subsets. We observed a striking upregulation of certain iRs following the cytokine production wave, in agreement with the notion that iRs function as a negative feedback mechanism. Intriguingly, we found no major impairment of cytokine production in cells positive for a broad array of iRs, as previously shown for PD1 in healthy donors. Rather, the expression of the various iRs strongly correlated with T cell differentiation or activation states, or both. Furthermore, we analyzed CD8 T cells from lymph nodes (LNs of melanoma patients. Interestingly, we found altered iR expression and lower cytokine production by T cells from metastatic LNs, but also from non-metastatic LNs, likely due to mechanisms which are not related to exhaustion. Together, our data shows that expression of iRs per se does not mark dysfunctional cells, but is rather tightly linked to activation and differentiation. This study highlights the importance of considering the status of activation and differentiation for the study and the clinical monitoring of CD8 T cells.

  12. Praziquantel Facilitates IFN-γ-Producing CD8+ T Cells (Tc1) and IL-17-Producing CD8+ T Cells (Tc17) Responses to DNA Vaccination in Mice

    OpenAIRE

    Qiang Zou; Xin Yao; Jin Feng; Zhinan Yin; Richard Flavell; Yanxin Hu; Guoxing Zheng; Jin Jin; Youmin Kang; Bing Wu; Xiaoxuan Liang; Congcong Feng; Hu Liu; Weiyi Li; Xianzheng Wang

    2011-01-01

    BACKGROUND: CD8(+) cytotoxic T lymphocytes (CTLs) are crucial for eliminating hepatitis B virus (HBV) infected cells. DNA vaccination, a novel therapeutic strategy for chronic virus infection, has been shown to induce CTL responses. However, accumulated data have shown that CTLs could not be effectively induced by HBV DNA vaccination. METHODOLOGY/PRINCIPAL FINDINGS: Here, we report that praziquantel (PZQ), an anti-schistoma drug, could act as an adjuvant to overcome the lack of potent CTL res...

  13. Decreased numbers of CD4+ naive and effector memory T cells, and CD8+ naïve T cells, are associated with trichloroethylene exposure

    Directory of Open Access Journals (Sweden)

    H Dean eHosgood

    2012-01-01

    Full Text Available Trichloroethylene (TCE is a volatile chlorinated organic compound that is commonly used as a solvent for lipophilic compounds. Although recognized as an animal carcinogen, TCE’s carcinogenic potential in humans is still uncertain. We have carried out a cross-sectional study of 80 workers exposed to TCE and 96 unexposed controls matched on age and sex in Guangdong, China to study TCE’s early biologic effects. We previously reported that the total lymphocyte count and each of the major lymphocyte subsets (i.e., CD4+ T cells, CD8+ T cells, natural killer (NK cells, and B cells were decreased in TCE-exposed workers compared to controls, suggesting a selective effect on lymphoid progenitors and/or lymphocyte survival. To explore which T lymphocyte subsets are affected, we investigated the effect of TCE exposure on the numbers of CD4+ naïve and memory T cells, CD8+ naïve and memory T cells, and regulatory T cells by FACS analysis. Linear regression of each subset was used to test for differences between exposed workers and controls adjusting for potential confounders. We observed that CD4+ and CD8+ naïve T cell counts were about 8% (p = 0.056 and 17% (p = 0.0002 lower, respectively, among exposed workers. CD4+ effector memory T cell counts were decreased by about 20% among TCE exposed workers compared to controls (p = 0.001. The selective targeting of TCE on CD8+ naïve and possibly CD4+ naive T cells, and CD4+ effector memory T cells, provide further insights into the immunosuppression-related response of human immune cells upon TCE exposure.

  14. A temporal role of type I interferon signaling in CD8+ T cell maturation during acute West Nile virus infection.

    Directory of Open Access Journals (Sweden)

    Amelia K Pinto

    2011-12-01

    Full Text Available A genetic absence of the common IFN-α/β signaling receptor (IFNAR in mice is associated with enhanced viral replication and altered adaptive immune responses. However, analysis of IFNAR(-/- mice is limited for studying the functions of type I IFN at discrete stages of viral infection. To define the temporal functions of type I IFN signaling in the context of infection by West Nile virus (WNV, we treated mice with MAR1-5A3, a neutralizing, non cell-depleting anti-IFNAR antibody. Inhibition of type I IFN signaling at or before day 2 after infection was associated with markedly enhanced viral burden, whereas treatment at day 4 had substantially less effect on WNV dissemination. While antibody treatment prior to infection resulted in massive expansion of virus-specific CD8(+ T cells, blockade of type I IFN signaling starting at day 4 induced dysfunctional CD8(+ T cells with depressed cytokine responses and expression of phenotypic markers suggesting exhaustion. Thus, only the later maturation phase of anti-WNV CD8(+ T cell development requires type I IFN signaling. WNV infection experiments in BATF3(-/- mice, which lack CD8-α dendritic cells and have impaired priming due to inefficient antigen cross-presentation, revealed a similar effect of blocking IFN signaling on CD8(+ T cell maturation. Collectively, our results suggest that cell non-autonomous type I IFN signaling shapes maturation of antiviral CD8(+ T cell response at a stage distinct from the initial priming event.

  15. Evidence from Human and Animal Studies: Pathological Roles of CD8+ T Cells in Autoimmune Peripheral Neuropathies

    Science.gov (United States)

    Yang, Mu; Peyret, Corentin; Shi, Xiang Qun; Siron, Nicolas; Jang, Jeong Ho; Wu, Sonia; Fournier, Sylvie; Zhang, Ji

    2015-01-01

    Autoimmune peripheral neuropathies such as Guillain-Barre Syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) affect millions of people worldwide. Despite significant advances in understanding the pathology, the molecular and cellular mechanisms of immune-mediated neuropathies remain elusive. T lymphocytes definitely play an important role in disease pathogenesis and CD4+ T cells have been the main area of research for decades. This is partly due to the fact that the most frequent animal model to study autoimmune peripheral neuropathy is experimental allergic neuritis (EAN). As it is induced commonly by immunization with peripheral nerve proteins, EAN is driven mainly by CD4+ T cells. However, similarly to what has been reported for patients suffering from multiple sclerosis, a significant body of evidence indicates that CD8+ T cells may play a pathogenic role in GBS and CIDP disease development and/or progression. Here, we summarize clinical studies pertaining to the presence and potential role of CD8+ T cells in autoimmune peripheral neuropathies. We also discuss the findings from our most recent studies using a transgenic mouse line (L31 mice) in which the T cell co-stimulator molecule B7.2 (CD86) is constitutively expressed in antigen presenting cells of the nervous tissues. L31 mice spontaneously develop peripheral neuropathy, and CD8+ T cells are found accumulating in peripheral nerves of symptomatic animals. Interestingly, depletion of CD4+ T cells accelerates disease onset and increases disease prevalence. Finally, we point out some unanswered questions for future research to dissect the critical roles of CD8+ T cells in autoimmune peripheral neuropathies. PMID:26528293

  16. Immunotherapy Expands and Maintains the Function of High-Affinity Tumor-Infiltrating CD8 T Cells In Situ.

    Science.gov (United States)

    Moran, Amy E; Polesso, Fanny; Weinberg, Andrew D

    2016-09-15

    Cancer cells harbor high-affinity tumor-associated Ags capable of eliciting potent antitumor T cell responses, yet detecting these polyclonal T cells is challenging. Therefore, surrogate markers of T cell activation such as CD69, CD44, and programmed death-1 (PD-1) have been used. We report in this study that in mice, expression of activation markers including PD-1 is insufficient in the tumor microenvironment to identify tumor Ag-specific T cells. Using the Nur77GFP T cell affinity reporter mouse, we highlight that PD-1 expression can be induced independent of TCR ligation within the tumor. Given this, we characterized the utility of the Nur77GFP model system in elucidating mechanisms of action of immunotherapies independent of PD-1 expression. Coexpression of Nur77GFP and OX40 identifies a polyclonal population of high-affinity tumor-associated Ag-specific CD8(+) T cells, which produce more IFN-γ in situ than OX40 negative and doubles in quantity with anti-OX40 and anti-CTLA4 mAb therapy but not with anti-PD-1 or programmed death ligand-1. Moreover, expansion of these high-affinity CD8 T cells prolongs survival of tumor-bearing animals. Upon chronic stimulation in tumors and after adoptive cell therapy, CD8 TCR signaling and Nur77GFP induction is impaired, and tumors progress. However, this can be reversed and overall survival significantly enhanced after adoptive cell therapy with agonist OX40 immunotherapy. Therefore, we propose that OX40 agonist immunotherapy can maintain functional TCR signaling of chronically stimulated tumor-resident CD8 T cells, thereby increasing the frequency of cytotoxic, high-affinity, tumor-associated Ag-specific cells. PMID:27503208

  17. Evidence from human and animal studies: Pathological roles of CD8+ T cells in autoimmune peripheral neuropathies

    Directory of Open Access Journals (Sweden)

    Mu eYang

    2015-10-01

    Full Text Available Autoimmune peripheral neuropathies such as Guillain Barre Syndrome (GBS and chronic inflammatory demyelinating polyneuropathy (CIDP affect millions of people worldwide. Despite significant advances in understanding the pathology, the molecular and cellular mechanisms of immune-mediated neuropathies remain elusive. T lymphocytes definitely play an important role in disease pathogenesis and CD4+ T cells have been the main area of research for decades. This is partly due to the fact that the most frequent animal model to study autoimmune peripheral neuropathy is experimental allergic neuritis (EAN. As it is induced commonly by immunization with peripheral nerve proteins, EAN is driven mainly by CD4+ T cells. However, similarly to what has been reported for patients suffering from multiple sclerosis, a significant body of evidence indicate that CD8+ T cells may play a pathogenic role in GBS and CIDP disease development and/or progression. Here, we summarize clinical studies pertaining to the presence and potential role of CD8+ T cells in autoimmune peripheral neuropathy. We also discuss the findings from our most recent studies using a transgenic mouse line (L31 mice in which the T cell co-stimulator molecule B7.2 (CD86 is constitutively expressed in antigen presenting cells of the nervous tissues. L31 mice spontaneously develop peripheral neuropathy, and CD8+ T cells are found accumulating in peripheral nerves of symptomatic animals. Interestingly, depletion of CD4+ T cells accelerates disease onset and increases disease prevalence. Finally, we point out some unanswered questions for future research to dissect the critical roles of CD8+ T cells in autoimmune peripheral neuropathies.

  18. Metabolic reprogramming towards aerobic glycolysis correlates with greater proliferative ability and resistance to metabolic inhibition in CD8 versus CD4 T cells.

    Directory of Open Access Journals (Sweden)

    Yilin Cao

    Full Text Available T lymphocytes (T cells undergo metabolic reprogramming after activation to provide energy and biosynthetic materials for growth, proliferation and differentiation. Distinct T cell subsets, however, adopt metabolic programs specific to support their needs. As CD4 T cells coordinate adaptive immune responses while CD8 T cells become cytotoxic effectors, we compared activation-induced proliferation and metabolic reprogramming of these subsets. Resting CD4 and CD8 T cells were metabolically similar and used a predominantly oxidative metabolism. Following activation CD8 T cells proliferated more rapidly. Stimulation led both CD4 and CD8 T cells to sharply increase glucose metabolism and adopt aerobic glycolysis as a primary metabolic program. Activated CD4 T cells, however, remained more oxidative and had greater maximal respiratory capacity than activated CD8 T cells. CD4 T cells were also associated with greater levels of ROS and increased mitochondrial content, irrespective of the activation context. CD8 cells were better able, however, to oxidize glutamine as an alternative fuel source. The more glycolytic metabolism of activated CD8 T cells correlated with increased capacity for growth and proliferation, along with reduced sensitivity of cell growth to metabolic inhibition. These specific metabolic programs may promote greater growth and proliferation of CD8 T cells and enhance survival in diverse nutrient conditions.

  19. Broadly targeted human cytomegalovirus-specific CD4+ and CD8+ T cells dominate the memory compartments of exposed subjects.

    Science.gov (United States)

    Sylwester, Andrew W; Mitchell, Bridget L; Edgar, John B; Taormina, Cara; Pelte, Christian; Ruchti, Franziska; Sleath, Paul R; Grabstein, Kenneth H; Hosken, Nancy A; Kern, Florian; Nelson, Jay A; Picker, Louis J

    2005-09-01

    Human cytomegalovirus (HCMV) infections of immunocompetent hosts are characterized by a dynamic, life-long interaction in which host immune responses, particularly of T cells, restrain viral replication and prevent disease but do not eliminate the virus or preclude transmission. Because HCMV is among the largest and most complex of known viruses, the T cell resources committed to maintaining this balance have never been characterized completely. Here, using cytokine flow cytometry and 13,687 overlapping 15mer peptides comprising 213 HCMV open reading frames (ORFs), we found that 151 HCMV ORFs were immunogenic for CD4(+) and/or CD8(+) T cells, and that ORF immunogenicity was influenced only modestly by ORF expression kinetics and function. We further documented that total HCMV-specific T cell responses in seropositive subjects were enormous, comprising on average approximately 10% of both the CD4(+) and CD8(+) memory compartments in blood, whereas cross-reactive recognition of HCMV proteins in seronegative individuals was limited to CD8(+) T cells and was rare. These data provide the first glimpse of the total human T cell response to a complex infectious agent and will provide insight into the rules governing immunodominance and cross-reactivity in complex viral infections of humans. PMID:16147978

  20. Lineage relationship of CD8+ T cell subsets is revealed by progressive changes in the epigenetic landscape

    Science.gov (United States)

    Crompton, Joseph G.; Narayanan, Manikandan; Cuddapah, Suresh; Roychoudhuri, Rahul; Ji, Yun; Yang, Wenjing; Patel, Shashank J.; Sukumar, Madhusudhanan; Palmer, Douglas C.; Peng, Weiqun; Wang, Ena; Marincola, Francesco M.; Klebanoff, Christopher A.; Zhao, Keji; Tsang, John S.; Gattinoni, Luca; Restifo, Nicholas P.

    2016-01-01

    To better elucidate epigenetic mechanisms that correlate with the dynamic gene expression program observed upon T-cell differentiation, we investigated the genomic landscape of histone modifications in naive and memory CD8+ T cells. Using a ChIP-Seq approach coupled with global gene expression profiling, we generated genome-wide histone H3 lysine 4 (H3K4me3) and H3 lysine 27 (H3K27me3) trimethylation maps in naive, T memory stem cells, central memory cells, and effector memory cells in order to gain insight into how histone architecture is remodeled during T cell differentiation. We show that H3K4me3 histone modifications are associated with activation of genes, while H3K27me3 is negatively correlated with gene expression at canonical loci and enhancers associated with T-cell metabolism, effector function, and memory. Our results also reveal histone modifications and gene expression signatures that distinguish the recently identified T memory stem cells from other CD8+ T-cell subsets. Taken together, our results suggest that CD8+ lymphocytes undergo chromatin remodeling in a progressive fashion. These findings have major implications for our understanding of peripheral T-cell ontogeny and the formation of immunological memory. PMID:25914936

  1. CD8+ T cells prevent antigen-induced antibody-dependent enhancement of dengue disease in mice.

    Science.gov (United States)

    Zellweger, Raphaël M; Eddy, William E; Tang, William W; Miller, Robyn; Shresta, Sujan

    2014-10-15

    Dengue virus (DENV) causes pathologies ranging from the febrile illness dengue fever to the potentially lethal severe dengue disease. A major risk factor for developing severe dengue disease is the presence of subprotective DENV-reactive Abs from a previous infection (or from an immune mother), which can induce Ab-dependent enhancement of infection (ADE). However, infection in the presence of subprotective anti-DENV Abs does not always result in severe disease, suggesting that other factors influence disease severity. In this study we investigated how CD8(+) T cell responses influence the outcome of Ab-mediated severe dengue disease. Mice were primed with aluminum hydroxide-adjuvanted UV-inactivated DENV prior to challenge with DENV. Priming failed to induce robust CD8(+) T cell responses, and it induced nonneutralizing Ab responses that increased disease severity upon infection. Transfer of exogenous DENV-activated CD8(+) T cells into primed mice prior to infection prevented Ab-dependent enhancement and dramatically reduced viral load. Our results suggest that in the presence of subprotective anti-DENV Abs, efficient CD8(+) T cell responses reduce the risk of Ab-mediated severe dengue disease. PMID:25217165

  2. Acute aerobic exercise in humans increases cytokine expression in CD27- but not CD27+ CD8+ T-cells

    NARCIS (Netherlands)

    E.C. LaVoy; J.A. Bosch; T.W. Lowder; R.J. Simpson

    2012-01-01

    Exercise alters the percentage of CD8+ T-cells in the bloodstream expressing type I and type II cytokines. It is unknown if this reflects a change in cytokine expression within individual cells, or whether these observations result from the exercise-induced shift in the proportions of early/intermed

  3. Reprogramming tumor-infiltrating dendritic cells for CD103+CD8+ mucosal T cell differentiation and breast cancer rejection

    Science.gov (United States)

    Wu, Te-Chia; Xu, Kangling; Banchereau, Romain; Marches, Florentina; Yu, Chun I; Martinek, Jan; Anguiano, Esperanza; Pedroza-Gonzalez, Alexander; Snipes, G. Jackson; O’Shaughnessy, Joyce; Nishimura, Stephen; Liu, Yong-Jun; Pascual, Virginia; Banchereau, Jacques; Oh, Sangkon; Palucka, Karolina

    2014-01-01

    Our studies showed that tumor-infiltrating dendritic cells (DC) in breast cancer drive inflammatory T helper 2 (iTh2) cells and protumor inflammation. Here we show that intratumoral delivery of the β-glucan curdlan, a ligand of dectin-1, blocks the generation of iTh2 cells, and prevents breast cancer progression in vivo. Curdlan reprograms tumor-infiltrating DC via the ligation of dectin-1, enabling the DC to become resistant to cancer-derived thymic stromal lymphopoietin (TSLP), to produce IL12p70, and to favor the generation of T helper 1 (Th1) cells. DC activated via dectin-1, but not those activated with TLR-7/8 ligand or poly IC, induce CD8+ T cells to express CD103 (αE integrin), a ligand for cancer cells E-cadherin. Generation of these mucosal CD8+ T cells is regulated by DC-derived integrin αvβ8 and TGF-β activation in a dectin-1-dependent fashion. These CD103+CD8+ mucosal T cells accumulate in the tumors thereby increasing cancer necrosis and inhibiting cancer progression in vivo in a humanized mouse model of breast cancer. Importantly, CD103+CD8+ mucosal T cells elicited by reprogrammed DC can reject established cancer. Thus, reprogramming tumor-infiltrating DC represents a new strategy for cancer rejection. PMID:24795361

  4. Enumeration of CD4 and CD8 T-cells in HIV infection in Zimbabwe using a manual immunocytochemical method

    DEFF Research Database (Denmark)

    Gomo, E; Ndhlovu, P; Vennervald, B J;

    2001-01-01

    Laboratory, Harare, Zimbabwe. SUBJECTS: 41 HIV positive and 11 HIV negative men and women from Harare participating in HIV studies at Blair Research Laboratory, Zimbabwe. MAIN OUTCOME MEASURES: CD4 and CD8 T-cell counts by FC and the IA method. RESULTS: The IA method and FC were highly correlated for CD4...

  5. CD8 T cell-mediated protection against liver-stage malaria: Lessons from a mouse model

    Directory of Open Access Journals (Sweden)

    John eHarty

    2014-06-01

    Full Text Available Malaria is a major global health problem, with severe mortality in children living is Sub-Saharan Africa, and there is currently no licensed effective vaccine. However, vaccine-induced protection from Plasmodium infection, the causative agent of malaria, was established for humans in small clinical trials and for rodents in the 1960’s. Soon after, a critical role for memory CD8 T cells in vaccine induced protection against Plasmodium liver-stage infection was established in rodent models and is assumed to apply to humans. However, these seminal early studies have led to only modest advances over the ensuing years in our understanding the basic features of memory CD8 T cells required for protection against liver-stage Plasmodium infection, an issue which has likely impeded the development of effective vaccines for humans. Given the ethical and practical limitations in gaining mechanistic insight from human vaccine and challenge studies, animal models still have an important role in dissecting the basic parameters underlying memory CD8 T cell immunity to Plasmodium. Here, we will highlight recent data from our own work in the mouse model of Plasmodium infection that identify quantitative and qualitative features of protective memory CD8 T cell responses. Finally, these lessons will be discussed in the context of recent findings from clinical trials of vaccine–induced protection in controlled human challenge models.

  6. CD8 T-cell-mediated protection against liver-stage malaria: lessons from a mouse model

    Science.gov (United States)

    Van Braeckel-Budimir, Natalija; Harty, John T.

    2014-01-01

    Malaria is a major global health problem, with severe mortality in children living in sub-Saharan Africa, and there is currently no licensed, effective vaccine. However, vaccine-induced protection from Plasmodium infection, the causative agent of malaria, was established for humans in small clinical trials and for rodents in the 1960s. Soon after, a critical role for memory CD8 T cells in vaccine-induced protection against Plasmodium liver-stage infection was established in rodent models and is assumed to apply to humans. However, these seminal early studies have led to only modest advances over the ensuing years in our understanding the basic features of memory CD8 T cells required for protection against liver-stage Plasmodium infection, an issue which has likely impeded the development of effective vaccines for humans. Given the ethical and practical limitations in gaining mechanistic insight from human vaccine and challenge studies, animal models still have an important role in dissecting the basic parameters underlying memory CD8 T-cell immunity to Plasmodium. Here, we will highlight recent data from our own work in the mouse model of Plasmodium infection that identify quantitative and qualitative features of protective memory CD8 T-cell responses. Finally, these lessons will be discussed in the context of recent findings from clinical trials of vaccine-induced protection in controlled human challenge models. PMID:24936199

  7. Identification of a human CD8+ regulatory T cell subset that mediates suppression through the chemokine CC chemokine ligand 4.

    NARCIS (Netherlands)

    Joosten, S.A.; Meijgaarden, K.E. van; Savage, N.D.; Boer, T. de; Triebel, F.; Wal, A. van der; Heer, E. de; Klein, M.R.; Geluk, A.; Ottenhoff, T.H.M.

    2007-01-01

    Regulatory T cells (Treg) comprise multiple subsets and are important in controlling immunity and inflammation. However, the induction and mode of action of the various distinct Treg subsets remain ill defined, particularly in humans. Here, we describe a human CD8+ lymphocyte activation gene-3 (LAG-

  8. Genome-Based In Silico Identification of New Mycobacterium tuberculosis Antigens Activating Polyfunctional CD8+ T Cells in Human Tuberculosis

    DEFF Research Database (Denmark)

    Tang, Sheila Tuyet; van Meijgaarden, Krista E.; Caccamo, Nadia;

    2011-01-01

    infection, because they were absent from M. tuberculosis-noninfected individuals. Control CMV peptide/HLA-A*0201 tetramers stained CD8(+) T cells in M. tuberculosis-infected and noninfected individuals equally, whereas Ebola peptide/HLA-A*0201 tetramers were negative. In conclusion, the M. tuberculosis...

  9. Increased Infiltration of CD8+ T Cells by Dacarbazine in a Patient with Mucosal Penile Melanoma Refractory to Nivolumab

    Science.gov (United States)

    Funazumi, Masato; Arima, Yumi; Kato, Kohei; Nojima, Kohei; Tanaka, Kentaro; Miura, Keiko; Yokozeki, Hiroo

    2016-01-01

    Primary penile melanomas are rare tumors that represent less than 0.1% of all melanomas. We report a case of a 60-year-old Japanese male with a mucosal penile melanoma and describe an increased CD8+ T cell infiltration in brain after dacarbazine (DTIC) administration. After partial penectomy and left inguinal lymphadenectomy, he developed multiple lung, bone, spleen, brain and skin metastases. He was treated with interferon-β, DTIC and nivolumab. However, the metastases were not reduced in size. Immunohistochemistry showed an increase of CD8+ T cell infiltration and programmed death-ligand 1 (PD-L1) expression after the administration of DTIC, but the expression of programmed cell death protein 1 (PD-1) was negative. We speculate that DTIC exerted immunostimulatory effects, but nivolumab was ineffective due to the negative expression of PD-1 and/or an insufficient infiltration of CD8+ T cells. Although this is only one case, this case report could be the first step to discuss the development of effective therapies against melanoma to take advantage of the increased CD8+ T cell infiltration elicited by chemotherapeutic agents. It would be beneficial to pay more attention to the relationship between DTIC and immune checkpoint modulators. PMID:27489432

  10. Increased Infiltration of CD8(+) T Cells by Dacarbazine in a Patient with Mucosal Penile Melanoma Refractory to Nivolumab.

    Science.gov (United States)

    Funazumi, Masato; Namiki, Takeshi; Arima, Yumi; Kato, Kohei; Nojima, Kohei; Tanaka, Kentaro; Miura, Keiko; Yokozeki, Hiroo

    2016-08-01

    Primary penile melanomas are rare tumors that represent less than 0.1% of all melanomas. We report a case of a 60-year-old Japanese male with a mucosal penile melanoma and describe an increased CD8(+) T cell infiltration in brain after dacarbazine (DTIC) administration. After partial penectomy and left inguinal lymphadenectomy, he developed multiple lung, bone, spleen, brain and skin metastases. He was treated with interferon-β, DTIC and nivolumab. However, the metastases were not reduced in size. Immunohistochemistry showed an increase of CD8(+) T cell infiltration and programmed death-ligand 1 (PD-L1) expression after the administration of DTIC, but the expression of programmed cell death protein 1 (PD-1) was negative. We speculate that DTIC exerted immunostimulatory effects, but nivolumab was ineffective due to the negative expression of PD-1 and/or an insufficient infiltration of CD8(+) T cells. Although this is only one case, this case report could be the first step to discuss the development of effective therapies against melanoma to take advantage of the increased CD8(+) T cell infiltration elicited by chemotherapeutic agents. It would be beneficial to pay more attention to the relationship between DTIC and immune checkpoint modulators. PMID:27489432

  11. The Combined Deficiency of Immunoproteasome Subunits Affects Both the Magnitude and Quality of Pathogen- and Genetic Vaccination-Induced CD8+ T Cell Responses to the Human Protozoan Parasite Trypanosoma cruzi

    Science.gov (United States)

    Ersching, Jonatan; Vasconcelos, José R.; Ferreira, Camila P.; Caetano, Braulia C.; Machado, Alexandre V.; Bruna–Romero, Oscar; Baron, Monique A.; Ferreira, Ludmila R. P.; Cunha-Neto, Edécio; Rock, Kenneth L.

    2016-01-01

    The β1i, β2i and β5i immunoproteasome subunits have an important role in defining the repertoire of MHC class I-restricted epitopes. However, the impact of combined deficiency of the three immunoproteasome subunits in the development of protective immunity to intracellular pathogens has not been investigated. Here, we demonstrate that immunoproteasomes play a key role in host resistance and genetic vaccination-induced protection against the human pathogen Trypanosoma cruzi (the causative agent of Chagas disease), immunity to which is dependent on CD8+ T cells and IFN-γ (the classical immunoproteasome inducer). We observed that infection with T. cruzi triggers the transcription of immunoproteasome genes, both in mice and humans. Importantly, genetically vaccinated or T. cruzi-infected β1i, β2i and β5i triple knockout (TKO) mice presented significantly lower frequencies and numbers of splenic CD8+ effector T cells (CD8+CD44highCD62Llow) specific for the previously characterized immunodominant (VNHRFTLV) H-2Kb-restricted T. cruzi epitope. Not only the quantity, but also the quality of parasite-specific CD8+ T cell responses was altered in TKO mice. Hence, the frequency of double-positive (IFN-γ+/TNF+) or single-positive (IFN-γ+) cells specific for the H-2Kb-restricted immunodominant as well as subdominant T. cruzi epitopes were higher in WT mice, whereas TNF single-positive cells prevailed among CD8+ T cells from TKO mice. Contrasting with their WT counterparts, TKO animals were also lethally susceptible to T. cruzi challenge, even after an otherwise protective vaccination with DNA and adenoviral vectors. We conclude that the immunoproteasome subunits are key determinants in host resistance to T. cruzi infection by influencing both the magnitude and quality of CD8+ T cell responses. PMID:27128676

  12. The Combined Deficiency of Immunoproteasome Subunits Affects Both the Magnitude and Quality of Pathogen- and Genetic Vaccination-Induced CD8+ T Cell Responses to the Human Protozoan Parasite Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Jonatan Ersching

    2016-04-01

    Full Text Available The β1i, β2i and β5i immunoproteasome subunits have an important role in defining the repertoire of MHC class I-restricted epitopes. However, the impact of combined deficiency of the three immunoproteasome subunits in the development of protective immunity to intracellular pathogens has not been investigated. Here, we demonstrate that immunoproteasomes play a key role in host resistance and genetic vaccination-induced protection against the human pathogen Trypanosoma cruzi (the causative agent of Chagas disease, immunity to which is dependent on CD8+ T cells and IFN-γ (the classical immunoproteasome inducer. We observed that infection with T. cruzi triggers the transcription of immunoproteasome genes, both in mice and humans. Importantly, genetically vaccinated or T. cruzi-infected β1i, β2i and β5i triple knockout (TKO mice presented significantly lower frequencies and numbers of splenic CD8+ effector T cells (CD8+CD44highCD62Llow specific for the previously characterized immunodominant (VNHRFTLV H-2Kb-restricted T. cruzi epitope. Not only the quantity, but also the quality of parasite-specific CD8+ T cell responses was altered in TKO mice. Hence, the frequency of double-positive (IFN-γ+/TNF+ or single-positive (IFN-γ+ cells specific for the H-2Kb-restricted immunodominant as well as subdominant T. cruzi epitopes were higher in WT mice, whereas TNF single-positive cells prevailed among CD8+ T cells from TKO mice. Contrasting with their WT counterparts, TKO animals were also lethally susceptible to T. cruzi challenge, even after an otherwise protective vaccination with DNA and adenoviral vectors. We conclude that the immunoproteasome subunits are key determinants in host resistance to T. cruzi infection by influencing both the magnitude and quality of CD8+ T cell responses.

  13. Interplay between CD8α+ dendritic cells and monocytes in response to Listeria monocytogenes infection attenuates T cell responses.

    Directory of Open Access Journals (Sweden)

    Dilnawaz Kapadia

    Full Text Available During the course of a microbial infection, different antigen presenting cells (APCs are exposed and contribute to the ensuing immune response. CD8α(+ dendritic cells (DCs are an important coordinator of early immune responses to the intracellular bacteria Listeria monocytogenes (Lm and are crucial for CD8(+ T cell immunity. In this study, we examine the contribution of different primary APCs to inducing immune responses against Lm. We find that CD8α(+ DCs are the most susceptible to infection while plasmacytoid DCs are not infected. Moreover, CD8α(+ DCs are the only DC subset capable of priming an immune response to Lm in vitro and are also the only APC studied that do so when transferred into β2 microglobulin deficient mice which lack endogenous cross-presentation. Upon infection, CD11b(+ DCs primarily secrete low levels of TNFα while CD8α(+ DCs secrete IL-12 p70. Infected monocytes secrete high levels of TNFα and IL-12p70, cytokines associated with activated inflammatory macrophages. Furthermore, co-culture of infected CD8α(+ DCs and CD11b+ DCs with monocytes enhances production of IL-12 p70 and TNFα. However, the presence of monocytes in DC/T cell co-cultures attenuates T cell priming against Lm-derived antigens in vitro and in vivo. This suppressive activity of spleen-derived monocytes is mediated in part by both TNFα and inducible nitric oxide synthase (iNOS. Thus these monocytes enhance IL-12 production to Lm infection, but concurrently abrogate DC-mediated T cell priming.

  14. Early priming minimizes the age-related immune compromise of CD8T cell diversity and function.

    Directory of Open Access Journals (Sweden)

    Sophie A Valkenburg

    2012-02-01

    Full Text Available The elderly are particularly susceptible to influenza A virus infections, with increased occurrence, disease severity and reduced vaccine efficacy attributed to declining immunity. Experimentally, the age-dependent decline in influenza-specific CD8(+ T cell responsiveness reflects both functional compromise and the emergence of 'repertoire holes' arising from the loss of low frequency clonotypes. In this study, we asked whether early priming limits the time-related attrition of immune competence. Though primary responses in aged mice were compromised, animals vaccinated at 6 weeks then challenged >20 months later had T-cell responses that were normal in magnitude. Both functional quality and the persistence of 'preferred' TCR clonotypes that expand in a characteristic immunodominance hierarchy were maintained following early priming. Similar to the early priming, vaccination at 22 months followed by challenge retained a response magnitude equivalent to young mice. However, late priming resulted in reduced TCRβ diversity in comparison with vaccination earlier in life. Thus, early priming was critical to maintaining individual and population-wide TCRβ diversity. In summary, early exposure leads to the long-term maintenance of memory T cells and thus preserves optimal, influenza-specific CD8(+ T-cell responsiveness and protects against the age-related attrition of naïve T-cell precursors. Our study supports development of vaccines that prime CD8(+ T-cells early in life to elicit the broadest possible spectrum of CD8(+ T-cell memory and preserve the magnitude, functionality and TCR usage of responding populations. In addition, our study provides the most comprehensive analysis of the aged (primary, secondary primed-early and secondary primed-late TCR repertoires published to date.

  15. The Prognostic Significance of FoxP3+ T Cells and CD8+ T Cells in Colorectal Carcinomas.

    Science.gov (United States)

    Argon, Asuman; Vardar, Enver; Kebat, Tulu; Erdinç, Ömer; Erkan, Nazif

    2016-01-01

    Recent studies report that tumor microenvironment effects prognosis of colorectal cancers. We analyzed the densities of FoxP3+ cells and CD8+ cells, the ratio of FoxP3+/CD8+ cells and the relationship between these parameters, clinicopathological features, and prognosis. A total of 186 colorectal adenocarcinoma were evaluated in terms of clinicopathological features. Immunohistochemically, densities of intratumoral (IT; IT-FoxP3) and nontumoral (NT; NT-FoxP3) FoxP3+ cells and IT-CD8 and NT-CD8 CD8+ cells were calculated. The ratio of Foxp3/CD8 was recorded. IT-FoxP3 and the ratio of IT-FoxP3/IT-CD8 were higher than NT-FoxP3 and the ratio of NT-FoxP3/NT-CD8, respectively. In multivariate analysis, high FoxP3+ cell density is the most important predictive marker after clinical stage and surgical margin positivity in disease-free survival and the most important predictive marker after clinical stage in overall survival (OS). Short OS time was correlated with clinical stage, decrease in IT-FoxP3, increasing age, number of metastatic lymph nodes, surgical margin positivity, satellite tumor nodule, medullary carcinoma, and the number of pericolorectal lymph nodes. The ratio of FoxP3/CD8 increased noticeably in the IT area, but no relationship was found with survival. The relationships of the cells with one another in the tumor microenvironment seem to have many secrets. Studies in large series supported by molecular techniques can illuminate those secrets to some extent. PMID:27481490

  16. CXCR3 expression defines a novel subset of innate CD8+ T cells that enhance immunity against bacterial infection and cancer upon stimulation with IL-15

    OpenAIRE

    Oghumu, Steve; Terrazas, Cesar A.; Varikuti, Sanjay; Kimble, Jennifer; Vadia, Stephen; Yu, Lianbo; Seveau, Stephanie; Abhay R Satoskar

    2014-01-01

    Innate CD8+ T cells are a heterogeneous population with developmental pathways distinct from conventional CD8+ T cells. However, their biology, classification, and functions remain incompletely understood. We recently demonstrated the existence of a novel population of chemokine (C-X-C motif) receptor 3 (CXCR3)-positive innate CD8+ T cells. Here, we investigated the functional properties of this subset and identified effector molecules and pathways which mediate their function. Adoptive trans...

  17. Virus-induced polyclonal T cell activation is followed by apoptosis: partitioning of CD8+ T cells based on alpha 4 integrin expression

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Röpke, C; Thomsen, Allan Randrup

    1996-01-01

    Systemic infection with lymphocytic choriomeningitis virus (LCMV) is accompanied by marked splenomegaly, primarily reflecting the accumulation of CD8(+) T cells with an activated phenotype (e.g. VLA-4hi). Analysis of DNA content using 7-aminoactinomycin-D revealed that as many as 30% of CD8(+) T...... cells are cycling around day 6 post-infection and that virtually all cycling cells express a high level of VLA-4. In accord with the relatively stable CD4+ cell number, only few cycling CD4+ cells were observed. Following virus control, splenic lymphocyte numbers decreased gradually and during...... this period many apoptotic cells were detected in the white pulp using terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling. Flow cytometric analysis of DNA content revealed a high frequency of cells with subnormal levels of DNA in the CD8(+)VLA-4hi subset, whereas the frequency...

  18. Interleukin-2 Enhances the Regulatory Functions of CD4(+)T Cell-Derived CD4(-)CD8(-) Double Negative T Cells.

    Science.gov (United States)

    Cong, Min; Liu, Tianhui; Tian, Dan; Guo, Hongbo; Wang, Ping; Liu, Kai; Lin, Jun; Tian, Yue; Shi, Wen; You, Hong; Jia, Jidong; Zhang, Dong

    2016-08-01

    CD4(+) T cells can be converted to CD4(-)CD8(-) double negative T cells (DN T cells) under appropriate conditions, and IL-2 enhanced the conversion. Here, we investigated the effect of IL-2 on the proliferation and function of converted DN T cells in vitro and in vivo. DN T cells were hyporesponsive when restimulated by mature dendritic cells (mDCs), IL-2 completely restored their responsiveness in vitro. In addition, IL-2 increased the resistance of DN T cells to apoptosis in vivo. DN T cells profoundly inhibited the proliferation of CD4(+)CD25(-) T effector cells triggered by mDCs in vitro, and this suppression was further enhanced by IL-2. Adoptively transferring of DN T cells, in combination with IL-2, inhibited the proliferation and enhanced apoptosis of alloreactive CD4(+) T cells, which resulted in significant prolongation of skin allograft survival time. Perforin plays a key role in the enhancement of DN T cells immune regulation by IL-2. In conclusion, we elucidated that IL-2 promoted DN T cell proliferation and suppressive function. The combination of DN T cells and exogenous IL-2 may represent a novel therapy in the clinical setting to prevent allograft rejection and induce immune tolerance. PMID:27135902

  19. The Herpes Simplex Virus Latency-Associated Transcript Gene Is Associated with a Broader Repertoire of Virus-Specific Exhausted CD8+ T Cells Retained within the Trigeminal Ganglia of Latently Infected HLA Transgenic Rabbits

    Science.gov (United States)

    Srivastava, Ruchi; Dervillez, Xavier; Khan, Arif A.; Chentoufi, Aziz A.; Chilukuri, Sravya; Shukr, Nora; Fazli, Yasmin; Ong, Nicolas N.; Afifi, Rasha E.; Osorio, Nelson; Geertsema, Roger; Nesburn, Anthony B.

    2016-01-01

    ABSTRACT Persistent pathogens, such as herpes simplex virus 1 (HSV-1), have evolved a variety of immune evasion strategies to avoid being detected and destroyed by the host's immune system. A dynamic cross talk appears to occur between the HSV-1 latency-associated transcript (LAT), the only viral gene that is abundantly transcribed during latency, and the CD8+ T cells that reside in HSV-1 latently infected human and rabbit trigeminal ganglia (TG). The reactivation phenotype of TG that are latently infected with wild-type HSV-1 or with LAT-rescued mutant (i.e., LAT+ TG) is significantly higher than TG latently infected with LAT-null mutant (i.e., LAT− TG). Whether LAT promotes virus reactivation by selectively shaping a unique repertoire of HSV-specific CD8+ T cells in LAT+ TG is unknown. In the present study, we assessed the frequency, function, and exhaustion status of TG-resident CD8+ T cells specific to 40 epitopes derived from HSV-1 gB, gD, VP11/12, and VP13/14 proteins, in human leukocyte antigen (HLA-A*0201) transgenic rabbits infected ocularly with LAT+ versus LAT– virus. Compared to CD8+ T cells from LAT– TG, CD8+ T cells from LAT+ TG (i) recognized a broader selection of nonoverlapping HSV-1 epitopes, (ii) expressed higher levels of PD-1, TIM-3, and CTLA-4 markers of exhaustion, and (iii) produced less tumor necrosis factor alpha, gamma interferon, and granzyme B. These results suggest a novel immune evasion mechanism by which the HSV-1 LAT may contribute to the shaping of a broader repertoire of exhausted HSV-specific CD8+ T cells in latently infected TG, thus allowing for increased viral reactivation. IMPORTANCE A significantly larger repertoire of dysfunctional (exhausted) HSV-specific CD8+ T cells were found in the TG of HLA transgenic rabbits latently infected with wild-type HSV-1 or with LAT-rescued mutant (i.e., LAT+ TG) than in a more restricted repertoire of functional HSV-specific CD8+ T cells in the TG of HLA transgenic rabbits latently

  20. Structural Basis of the CD8[alpha beta]/MHC Class I Interaction: Focused Recognition Orients CD8[beta] to a T Cell Proximal Position[superscript 1,2

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui; Natarajan, Kannan; Margulies, David H.; (NIH)

    2009-09-18

    In the immune system, B cells, dendritic cells, NK cells, and T lymphocytes all respond to signals received via ligand binding to receptors and coreceptors. Although the specificity of T cell recognition is determined by the interaction of T cell receptors with MHC/peptide complexes, the development of T cells in the thymus and their sensitivity to Ag are also dependent on coreceptor molecules CD8 (for MHC class I (MHCI)) and CD4 (for MHCII). The CD8{alpha}{beta} heterodimer is a potent coreceptor for T cell activation, but efforts to understand its function fully have been hampered by ignorance of the structural details of its interactions with MHCI. In this study we describe the structure of CD8{alpha}{beta} in complex with the murine MHCI molecule H-2D{sup d} at 2.6 {angstrom} resolution. The focus of the CD8{alpha}{beta} interaction is the acidic loop (residues 222-228) of the {alpha}3 domain of H-2D{sup d}. The {beta} subunit occupies a T cell membrane proximal position, defining the relative positions of the CD8{alpha} and CD8{beta} subunits. Unlike the CD8{alpha}{alpha} homodimer, CD8{alpha}{beta} does not contact the MHCI {alpha}{sub 2}- or {beta}{sub 2}-microglobulin domains. Movements of the CD8{alpha} CDR2 and CD8{beta} CDR1 and CDR2 loops as well as the flexibility of the H-2D{sup d} CD loop facilitate the monovalent interaction. The structure resolves inconclusive data on the topology of the CD8{alpha}{beta}/MHCI interaction, indicates that CD8{beta} is crucial in orienting the CD8{alpha}{beta} heterodimer, provides a framework for understanding the mechanistic role of CD8{alpha}{beta} in lymphoid cell signaling, and offers a tangible context for design of structurally altered coreceptors for tumor and viral immunotherapy.

  1. Human prostate tumor antigen-specific CD8+ regulatory T cells are inhibited by CTLA-4 or IL-35 blockade.

    Science.gov (United States)

    Olson, Brian M; Jankowska-Gan, Ewa; Becker, Jordan T; Vignali, Dario A A; Burlingham, William J; McNeel, Douglas G

    2012-12-15

    Regulatory T cells play important roles in cancer development and progression by limiting the generation of innate and adaptive anti-tumor immunity. We hypothesized that in addition to natural CD4(+)CD25(+) regulatory T cells (Tregs) and myeloid-derived suppressor cells, tumor Ag-specific Tregs interfere with the detection of anti-tumor immunity after immunotherapy. Using samples from prostate cancer patients immunized with a DNA vaccine encoding prostatic acid phosphatase (PAP) and a trans-vivo delayed-type hypersensitivity (tvDTH) assay, we found that the detection of PAP-specific effector responses after immunization was prevented by the activity of PAP-specific regulatory cells. These regulatory cells were CD8(+)CTLA-4(+), and their suppression was relieved by blockade of CTLA-4, but not IL-10 or TGF-β. Moreover, Ag-specific CD8(+) Tregs were detected prior to immunization in the absence of PAP-specific effector responses. These PAP-specific CD8(+)CTLA-4(+) suppressor T cells expressed IL-35, which was decreased after blockade of CTLA-4, and inhibition of either CTLA-4 or IL-35 reversed PAP-specific suppression of tvDTH response. PAP-specific CD8(+)CTLA-4(+) T cells also suppressed T cell proliferation in an IL-35-dependent, contact-independent fashion. Taken together, these findings suggest a novel population of CD8(+)CTLA-4(+) IL-35-secreting tumor Ag-specific Tregs arise spontaneously in some prostate cancer patients, persist during immunization, and can prevent the detection of Ag-specific effector responses by an IL-35-dependent mechanism.

  2. Exploring the induction of preproinsulin-specific Foxp3+ CD4+ Treg cells that inhibit CD8+ T cell-mediated autoimmune diabetes by DNA vaccination

    Science.gov (United States)

    Stifter, Katja; Schuster, Cornelia; Schlosser, Michael; Boehm, Bernhard Otto; Schirmbeck, Reinhold

    2016-01-01

    DNA vaccination is a promising strategy to induce effector T cells but also regulatory Foxp3+ CD25+ CD4+ Treg cells and inhibit autoimmune disorders such as type 1 diabetes. Little is known about the antigen requirements that facilitate priming of Treg cells but not autoreactive effector CD8+ T cells. We have shown that the injection of preproinsulin (ppins)-expressing pCI/ppins vector into PD-1- or PD-L1-deficient mice induced Kb/A12-21-monospecific CD8+ T cells and autoimmune diabetes. A pCI/ppinsΔA12-21 vector (lacking the critical Kb/A12-21 epitope) did not induce autoimmune diabetes but elicited a systemic Foxp3+ CD25+ Treg cell immunity that suppressed diabetes induction by a subsequent injection of the diabetogenic pCI/ppins. TGF-β expression was significantly enhanced in the Foxp3+ CD25+ Treg cell population of vaccinated/ppins-primed mice. Ablation of Treg cells in vaccinated/ppins-primed mice by anti-CD25 antibody treatment abolished the protective effect of the vaccine and enabled diabetes induction by pCI/ppins. Adoptive transfer of Treg cells from vaccinated/ppins-primed mice into PD-L1−/− hosts efficiently suppressed diabetes induction by pCI/ppins. We narrowed down the Treg-stimulating domain to a 15-residue ppins76–90 peptide. Vaccine-induced Treg cells thus play a crucial role in the control of de novo primed autoreactive effector CD8+ T cells in this diabetes model. PMID:27406624

  3. Exploring the induction of preproinsulin-specific Foxp3(+) CD4(+) Treg cells that inhibit CD8(+) T cell-mediated autoimmune diabetes by DNA vaccination.

    Science.gov (United States)

    Stifter, Katja; Schuster, Cornelia; Schlosser, Michael; Boehm, Bernhard Otto; Schirmbeck, Reinhold

    2016-01-01

    DNA vaccination is a promising strategy to induce effector T cells but also regulatory Foxp3(+) CD25(+) CD4(+) Treg cells and inhibit autoimmune disorders such as type 1 diabetes. Little is known about the antigen requirements that facilitate priming of Treg cells but not autoreactive effector CD8(+) T cells. We have shown that the injection of preproinsulin (ppins)-expressing pCI/ppins vector into PD-1- or PD-L1-deficient mice induced K(b)/A12-21-monospecific CD8(+) T cells and autoimmune diabetes. A pCI/ppinsΔA12-21 vector (lacking the critical K(b)/A12-21 epitope) did not induce autoimmune diabetes but elicited a systemic Foxp3(+) CD25(+) Treg cell immunity that suppressed diabetes induction by a subsequent injection of the diabetogenic pCI/ppins. TGF-β expression was significantly enhanced in the Foxp3(+) CD25(+) Treg cell population of vaccinated/ppins-primed mice. Ablation of Treg cells in vaccinated/ppins-primed mice by anti-CD25 antibody treatment abolished the protective effect of the vaccine and enabled diabetes induction by pCI/ppins. Adoptive transfer of Treg cells from vaccinated/ppins-primed mice into PD-L1(-/-) hosts efficiently suppressed diabetes induction by pCI/ppins. We narrowed down the Treg-stimulating domain to a 15-residue ppins76-90 peptide. Vaccine-induced Treg cells thus play a crucial role in the control of de novo primed autoreactive effector CD8(+) T cells in this diabetes model. PMID:27406624

  4. Induction of CD8+ T-cell responses against subunit antigens by the novel cationic liposomal CAF09 adjuvant

    DEFF Research Database (Denmark)

    Korsholm, Karen Smith; Hansen, Jon; Karlsen, Kasper;

    2014-01-01

    previously described CTL-inducing adjuvants, CAF05 (DDA/trehalose dibehenate (TDB)/Poly(I:C)), Aluminium/monophosphoryl lipid-A (MPL) and Montanide/CpG/IL-2. The optimal effect was obtained when the CAF09-adjuvanted vaccine was administered by the i.p. route, whereas s.c. administration primed limited CD8+ T......-cell responses. The CD4+ T cells induced by CAF09 were mainly of an effector-memory-like phenotype and the CD8+ T cells were highly cytotoxic. Finally, in a mouse therapeutic skin tumor model, the HPV-16 E7 antigen formulated in CAF09 significantly reduced the growth of already established subcutaneous E7...

  5. HTLV-1 specific CD8+ T cell function augmented by blockade of 2B4/CD48 interaction in HTLV-1 infection.

    Directory of Open Access Journals (Sweden)

    Chibueze Chioma Ezinne

    Full Text Available CD8+ T cell response is important in the response to viral infections; this response though is regulated by inhibitory receptors. Expression of inhibitory receptors has been positively correlated with CD8+ T cell exhaustion; the consequent effect of simultaneous blockade of these inhibitory receptors on CD8+ T cell response in viral infections have been studied, however, the role of individual blockade of receptor-ligand pair is unclear. 2B4/CD48 interaction is involved in CD8+T cell regulation, its signal transducer SAP (signaling lymphocyte activation molecule (SLAM-associated protein is required for stimulatory function of 2B4/CD244 on lymphocytes hence, we analyzed 2B4/CD244 (natural killer cell receptor and SAP (signaling lymphocyte activation molecule(SLAM-associated protein on total CD8+ and HTLV-1 specific CD8+T cells in HTLV-1 infection and the effect of blockade of interaction with ligand CD48 on HTLV-1 specific CD8+ T cell function. We observed a high expression of 2B4/CD244 on CD8+ T cells relative to uninfected and further upregulation on HTLV-1 specific CD8+ T cells. 2B4+ CD8+ T cells exhibited more of an effector and terminally differentiated memory phenotype. Blockade of 2B4/CD48 interaction resulted in improvement in function via perforin expression and degranulation as measured by CD107a surface mobilization on HTLV-1 specific CD8+ T cells. In the light of these findings, we thus propose an inhibitory role for 2B4/CD48 interaction on CD8+T cell function.

  6. Differential migration of passenger leukocytes and rapid deletion of naive alloreactive CD8 T cells after mouse liver transplantation.

    Science.gov (United States)

    Tay, Szun S; Lu, Bo; Sierro, Fred; Benseler, Volker; McGuffog, Claire M; Bishop, G Alex; Cowan, Peter J; McCaughan, Geoffrey W; Dwyer, Karen M; Bowen, David G; Bertolino, Patrick

    2013-11-01

    Donor passenger leukocytes (PLs) from transplanted livers migrate to recipient lymphoid tissues, where they are thought to induce the deletion of donor-specific T cells and tolerance. Difficulties in tracking alloreactive T cells and PLs in rats and in performing this complex surgery in mice have limited progress in identifying the contribution of PL subsets and sites and the kinetics of T cell deletion. Here we developed a mouse liver transplant model in which PLs, recipient cells, and a reporter population of transgenic CD8 T cells specific for the graft could be easily distinguished and quantified in allografts and recipient organs by flow cytometry. All PL subsets circulated rapidly via the blood as soon as 1.5 hours after transplantation. By 24 hours, PLs were distributed differently in the lymph nodes and spleen, whereas donor natural killer and natural killer T cells remained in the liver and blood. Reporter T cells were activated in both liver and lymphoid tissues, but their numbers dramatically decreased within the first 48 hours. These results provide the first unequivocal demonstration of the differential recirculation of liver PL subsets after transplantation, and show that alloreactive CD8 T cells are deleted more rapidly than initially reported. This model will be useful for dissecting early events leading to the spontaneous acceptance of liver transplants.

  7. Changes of CD8+ T cells in dextran sulfate sodium-induced colitis mice pretreated with oral immune regulation

    Institute of Scientific and Technical Information of China (English)

    YE Yue-fang; JIN Xi; CHEN Shao-hua; YUE Min; LI You-ming

    2012-01-01

    Background It has been reported that CD8+ regulatory cells could be induced upon oral tolerance.The purpose of this study was to investigate the changes of CD8α+ T cells in dextran sulfate sodium (DSS)-induced colitis mice pretreated by oral immune regulation.Methods The effects of five low oral doses of colitis-extracted proteins (CEP) on colitis were evaluated by clinical manifestation and histological lesions.The percentages of CD8α+ T ceils gating on CD3+ T cells were evaluated in the gut-associated lymphoid tissues (GALT) and the spleens by flow cytometry.Differences between the two groups were compared by Student's t test or Mann-Whitney U test.Results Compared to bovine serum albumin (BSA)-fed control mice,administration of CEP resulted in marked alleviation of colitis.The proportion of CD8α+ T cells,not only in intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) of the large intestine (LI) but also in spleen from CEP-fed colitis mice,was significantly higher than that from BSA-fed colitis mice (LI-IELs:(71.5±5.4)% vs.(60.1±4.3)%,P <0.01; LI-LPLs:(60.7±5.2)% vs.(51.9±4.7)%,P<0.01; spleen:(24.1±3.6)% vs.(20.3±4.1)%,P <0.05; n=8).Mucosal repair in repair-period mice five days after termination of DSS treatment was also accompanied by an increase of CD8α+ T cells in large intestinal mucosal lymphocytes (LI-IELs:(72.1±3.7)% vs.(61.5±4.5)%,P <0.01; LI-LPLs:(62.1±5.7)% vs.(52.7±3.6)%,P <0.01; n=8).The proportion of CD3+ T cells increased in Peyer's patches (PPs) and decreased in mesenteric lymph nodes (MLNs) from colitis mice compared to untreated mice,whereas the change pattern of CD3+T cells in PPs and MLNs from CEP-fed colitis mice was just on the contrary.Conclusion Improvement of DSS-induced colitis resulted from oral immune regulation is associated with an increase in CD8α+ T cells in spleen and large intestinal mucosa.

  8. T-cell receptor Vβ repertoire of CD8+ T-lymphocyte subpopulations in cutaneous leishmaniasis patients from the state of Rio de Janeiro, Brazil

    Science.gov (United States)

    Ferraz, Raquel; Cunha, Clarissa Ferreira; Pimentel, Maria Inês; Lyra, Marcelo Rosandiski; Schubach, Armando Oliveira; de Mendonça, Sérgio Coutinho Furtado; Da-Cruz, Alda Maria; Bertho, Alvaro Luiz

    2015-01-01

    In human cutaneous leishmaniasis (CL), the immune response is mainly mediated by T-cells. The role of CD8+ T-lymphocytes, which are related to healing or deleterious functions, in affecting clinical outcome is controversial. The aim of this study was to evaluate T-cell receptor diversity in late-differentiated effector (LDE) and memory CD8+ T-cell subsets in order to create a profile of specific clones engaged in deleterious or protective CL immune responses. Healthy subjects, patients with active disease (PAD) and clinically cured patients were enrolled in the study. Total CD8+ T-lymphocytes showed a disturbance in the expression of the Vβ2, Vβ9, Vβ13.2, Vβ18 and Vβ23 families. The analyses of CD8+T-lymphocyte subsets showed high frequencies of LDE CD8+T-lymphocytes expressing Vβ12 and Vβ22 in PAD, as well as effector-memory CD8+ T-cells expressing Vβ22. We also observed low frequencies of effector and central-memory CD8+ T-cells expressing Vβ2 in PAD, which correlated with a greater lesion size. Particular Vβ expansions point to CD8+ T-cell clones that are selected during CL immune responses, suggesting that CD8+ T-lymphocytes expressing Vβ12 or Vβ22 are involved in a LDE response and that Vβ2 contractions in memory CD8+T-cells are associated with larger lesions. PMID:26107186

  9. Cooperativity of HIV-Specific Cytolytic CD4 T Cells and CD8 T Cells in Control of HIV Viremia

    OpenAIRE

    Johnson, Susan; Eller, Michael; Teigler, Jeffrey E.; Maloveste, Sebastien M.; Schultz, Bruce T.; Soghoian, Damien Z.; Lu, Richard; Oster, Alexander F.; Chenine, Agnès-Laurence; Alter, Galit; Dittmer, Ulf; Marovich, Mary; Merlin L Robb; Michael, Nelson L.; Bolton, Diane

    2015-01-01

    CD4+ T cells play a pivotal role in the control of chronic viral infections. Recently, nontraditional CD4+ T cell functions beyond helper effects have been described, and a role for cytolytic CD4+ T cells in the control of HIV infection has been suggested. We define here the transcriptional, phenotypic, and functional profiles of HIV-specific cytolytic CD4+ T cells. Fluidigm BioMark and multiparameter flow cytometric analysis of HIV-specific cytolytic CD4+ T cells revealed a distinct transcri...

  10. Lymphocytic choriomeningitis virus infection is associated with long-standing perturbation of LFA-1 expression on CD8+ T cells

    DEFF Research Database (Denmark)

    Andersson, E C; Christensen, Jan Pravsgaard; Scheynius, A;

    1995-01-01

    belonged to the CD8+LFA-1hi subset and, correspondingly, the ligand ICAM-1 was found to be up-regulated on endothelial cells in the inflamed meninges. Preincubation of LCMV-primed donor splenocytes with anti-LFA-1 markedly inhibited the transfer of virus-specific delayed-type hypersensitivity to naive...... recipients. Together, these findings indicate that up-regulation of LFA-1 expression is a critical factor involved in directing activated CD8+ T cells to sites of viral infection....

  11. Arsenic trioxide inhibits accelerated allograft rejection mediated by alloreactive CD8(+) memory T cells and prolongs allograft survival time.

    Science.gov (United States)

    Li, Chun; Guan, Tianjun; Gao, Chang; Lin, Yingying; Yan, Guoliang; Zhu, Maoshu; Lv, Chongshan; Xia, Junjie; Qi, Zhongquan

    2015-09-01

    CD8(+) memory T (Tm) cells are a significant barrier to transplant tolerance induction in alloantigen-primed recipients, and are insensitive to existing clinical immunosuppressants. Here, we studied the inhibition of CD8(+) Tm cells by arsenic trioxide (As2O3) for the first time. Alloantigen-primed CD8(+) Tm cells were transferred to T cell immunodeficient nude mice. The mice were subjected to heart allotransplantation, and treated with As2O3. The transplant survival time was determined, and the inhibitory effects of As2O3 on CD8(+) Tm cell-mediated immune rejection were assessed through serological studies and inspection of the transplanted heart and lymphoid organs. We found that As2O3 treatment prolonged the mean survival time of the graft and reduced the number of CD8(+) Tm cells in the spleen and lymph nodes. The expression of the genes encoding interleukin (IL)-2, and IFN-γ was reduced, while expression of IL-10 and transforming growth factor-β was increased in the transplant. Our findings show that As2O3 treatment inhibits allograft rejection mediated by alloreactive CD8(+) Tm cells in the mouse heart transplantation model.

  12. The polyfunctionality of human memory CD8+ T cells elicited by acute and chronic virus infections is not influenced by age.

    Directory of Open Access Journals (Sweden)

    Alina Lelic

    Full Text Available As humans age, they experience a progressive loss of thymic function and a corresponding shift in the makeup of the circulating CD8+ T cell population from naïve to memory phenotype. These alterations are believed to result in impaired CD8+ T cell responses in older individuals; however, evidence that these global changes impact virus-specific CD8+ T cell immunity in the elderly is lacking. To gain further insight into the functionality of virus-specific CD8+ T cells in older individuals, we interrogated a cohort of individuals who were acutely infected with West Nile virus (WNV and chronically infected with Epstein Barr virus (EBV and Cytomegalovirus (CMV. The cohort was stratified into young (60 yrs groups. In the aged cohort, the CD8+ T cell compartment displayed a marked reduction in the frequency of naïve CD8+ T cells and increased frequencies of CD8+ T cells that expressed CD57 and lacked CD28, as previously described. However, we did not observe an influence of age on either the frequency of virus-specific CD8+ T cells within the circulating pool nor their functionality (based on the production of IFNγ, TNFα, IL2, Granzyme B, Perforin and mobilization of CD107a. We did note that CD8+ T cells specific for WNV, CMV or EBV displayed distinct functional profiles, but these differences were unrelated to age. Collectively, these data fail to support the hypothesis that immunosenescence leads to defective CD8+ T cell immunity and suggest that it should be possible to develop CD8+ T cell vaccines to protect aged individuals from infections with novel emerging viruses.

  13. Functional impairment of Tax-specific but not cytomegalovirus-specific CD8+ T lymphocytes in a minor population of asymptomatic human T-cell leukemia virus type 1-carriers

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    Takamori Ayako

    2011-12-01

    Full Text Available Abstract Background Human T-cell leukemia virus type 1 (HTLV-1 causes adult T-cell leukemia (ATL and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP in a small percentage of infected individuals. ATL is often associated with general immune suppression and an impaired HTLV-1-specific T-cell response, an important host defense system. We previously found that a small fraction of asymptomatic HTLV-1-carriers (AC already showed impaired T-cell responses against the major target antigen, Tax. However, it is unclear whether the impaired HTLV-1 Tax-specific T-cell response in these individuals is an HTLV-1-specific phenomenon, or merely reflects general immune suppression. In this study, in order to characterize the impaired HTLV-1-specific T-cell response, we investigated the function of Tax-specific CD8+ T-cells in various clinical status of HTLV-1 infection. Results By using tetramers consisting of HLA-A*0201, -A*2402, or -A*1101, and corresponding Tax epitope peptides, we detected Tax-specific CD8+ T-cells in the peripheral blood from 87.0% of ACs (n = 20/23 and 100% of HAM/TSP patients (n = 18/18 tested. We also detected Tax-specific CD8+ T-cells in 38.1% of chronic type ATL (cATL patients (n = 8/21, although its frequencies in peripheral blood CD8+ T cells were significantly lower than those of ACs or HAM/TSP patients. Tax-specific CD8+ T-cells detected in HAM/TSP patients proliferated well in culture and produced IFN-γ when stimulated with Tax peptides. However, such functions were severely impaired in the Tax-specific CD8+ T-cells detected in cATL patients. In ACs, the responses of Tax-specific CD8+ T-cells were retained in most cases. However, we found one AC sample whose Tax-specific CD8+ T-cells hardly produced IFN-γ, and failed to proliferate and express activation (CD69 and degranulation (CD107a markers in response to Tax peptide. Importantly, the same AC sample contained cytomegalovirus (CMV pp65-specific CD8+ T-cells

  14. Toxin coupled MHC class I tetramers can specifically ablate autoreactive CD8+ T cells and delay diabetes in NOD mice1

    OpenAIRE

    Vincent, Benjamin G.; Young, Ellen F.; Buntzman, Adam S.; Stevens, Rosemary; Kepler, Thomas B.; Tisch, Roland; Frelinger, Jeffrey A.; Hess, Paul R.

    2010-01-01

    There is compelling evidence that self reactive CD8+ T cells are a major factor in development and progression of Type 1 diabetes in animals and humans. Hence, great effort has been expended to define the specificity of autoimmune CD8+ T cells, and to alter their responses. Much work has focused on tolerization of T cells using proteins or peptides. A weakness in this approach is residual autoreactive T cells may be activated and exacerbate disease.

  15. Ex Vivo Restimulation of Human PBMC Expands a CD3+CD4−CD8− γδ + T Cell Population That Can Confound the Evaluation of CD4 and CD8 T Cell Responses to Vaccination

    OpenAIRE

    B. J. Sedgmen; Papalia, L.; Wang, L; Dyson, A. R.; McCallum, H. A.; C. M. Simson; Pearse, M. J.; Maraskovsky, E.; Hung, D; P. P. Eomois; Hartel, G.; Barnden, M. J.; Rockman, S. P.

    2013-01-01

    The measurement of vaccine-induced humoral and CD4+ and CD8+ cellular immune responses represents an important correlate of vaccine efficacy. Accurate and reliable assays evaluating such responses are therefore critical during the clinical development phase of vaccines. T cells play a pivotal role both in coordinating the adaptive and innate immune responses and as effectors. During the assessment of cell-mediated immunity (CMI) in subjects participating in a large-scale influenza vaccine tri...

  16. Cross-clade conservation of HIV type 1 Nef immunodominant regions recognized by CD8+ T cells of HIV type 1 CRF02_AG-infected Ivorian (West Africa).

    Science.gov (United States)

    Inwoley, André; Recordon-Pinson, Patricia; Dupuis, Marion; Gaston, Jessintha; Genête, Mathieu; Minga, Albert; Letourneur, Franck; Rouet, François; Choppin, Jeannine; Fleury, Hervé; Guillet, Jean-Gérard; Andrieu, Muriel

    2005-07-01

    Most HIV vaccine trials in the world are conducted with clade B while most circulating viral strains in Africa are non-B subtypes. We determined whether CD8+ T cells from HIV-1 intersubtype CRF02_AG-infected Ivorian individuals were able to recognize clade B epitopes. CD8+ T cell responses of nine HIV-1 intersubtype CRF02_AG-infected Ivorian patients and nine HIV-1 subtype B-infected French patients were studied using pools of HIV-1 clade B peptides (110 well-defined HIV CD8+ T cell epitopes) in an ELISPOT IFN-gamma assay. There was no difference in the number of recognized peptide pools between Ivorian and French cohorts (mean of four pools in both cases). Ivorian individuals had generated CD8+ T cell responses cross-reactive against HIV-1 subtype B and some individual peptides had been identified. Furthermore, sequence analysis of nef HIV genes of the Ivorian patients and nef cloning in two patients revealed very few variations between HIV- 1 intersubtype CRF02_AG and subtype B in nef immunodominant regions included in HIV clade B lipopeptide vaccines, currently tested in France.

  17. Identification of prostate-specific G-protein coupled receptor as a tumor antigen recognized by CD8(+ T cells for cancer immunotherapy.

    Directory of Open Access Journals (Sweden)

    Satoko Matsueda

    Full Text Available BACKGROUND: Prostate cancer is the most common cancer among elderly men in the US, and immunotherapy has been shown to be a promising strategy to treat patients with metastatic castration-resistant prostate cancer. Efforts to identify novel prostate specific tumor antigens will facilitate the development of effective cancer vaccines against prostate cancer. Prostate-specific G-protein coupled receptor (PSGR is a novel antigen that has been shown to be specifically over-expressed in human prostate cancer tissues. In this study, we describe the identification of PSGR-derived peptide epitopes recognized by CD8(+ T cells in an HLA-A2 dependent manner. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-one PSGR-derived peptides were predicted by an immuno-informatics approach based on the HLA-A2 binding motif. These peptides were examined for their ability to induce peptide-specific T cell responses in peripheral blood mononuclear cells (PBMCs obtained from either HLA-A2(+ healthy donors or HLA-A2(+ prostate cancer patients. The recognition of HLA-A2 positive and PSGR expressing LNCaP cells was also tested. Among the 21 PSGR-derived peptides, three peptides, PSGR3, PSGR4 and PSGR14 frequently induced peptide-specific T cell responses in PBMCs from both healthy donors and prostate cancer patients. Importantly, these peptide-specific T cells recognized and killed LNCaP prostate cancer cells in an HLA class I-restricted manner. CONCLUSIONS/SIGNIFICANCE: We have identified three novel HLA-A2-restricted PSGR-derived peptides recognized by CD8(+ T cells, which, in turn, recognize HLA-A2(+ and PSGR(+ tumor cells. The PSGR-derived peptides identified may be used as diagnostic markers as well as immune targets for development of anticancer vaccines.

  18. Antigen availability determines CD8T cell-dendritic cell interaction kinetics and memory fate decisions.

    Science.gov (United States)

    Henrickson, Sarah E; Perro, Mario; Loughhead, Scott M; Senman, Balimkiz; Stutte, Susanne; Quigley, Michael; Alexe, Gabriela; Iannacone, Matteo; Flynn, Michael P; Omid, Shaida; Jesneck, Jonathan L; Imam, Sabrina; Mempel, Thorsten R; Mazo, Irina B; Haining, W Nicholas; von Andrian, Ulrich H

    2013-09-19

    T cells are activated by antigen (Ag)-bearing dendritic cells (DCs) in lymph nodes in three phases. The duration of the initial phase of transient, serial DC-T cell interactions is inversely correlated with Ag dose. The second phase, characterized by stable DC-T cell contacts, is believed to be necessary for full-fledged T cell activation. Here we have shown that this is not the case. CD8T cells interacting with DCs presenting low-dose, short-lived Ag did not transition to phase 2, whereas higher Ag dose yielded phase 2 transition. Both antigenic constellations promoted T cell proliferation and effector differentiation but yielded different transcriptome signatures at 12 hr and 24 hr. T cells that experienced phase 2 developed long-lived memory, whereas conditions without stable contacts yielded immunological amnesia. Thus, T cells make fate decisions within hours after Ag exposure, resulting in long-term memory or abortive effector responses, correlating with T cell-DCs interaction kinetics. PMID:24054328

  19. Regulatory CD8{sup +} T cells induced by exposure to all-trans retinoic acid and TGF-{beta} suppress autoimmune diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Kishi, Minoru [Department of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan); Yasuda, Hisafumi, E-mail: yasuda@med.kobe-u.ac.jp [Department of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan); Abe, Yasuhisa; Sasaki, Hirotomo; Shimizu, Mami; Arai, Takashi; Okumachi, Yasuyo; Moriyama, Hiroaki; Hara, Kenta; Yokono, Koichi; Nagata, Masao [Department of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)

    2010-03-26

    Antigen-specific regulatory CD4{sup +} T cells have been described but there are few reports on regulatory CD8{sup +} T cells. We generated islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)-specific regulatory CD8{sup +} T cells from 8.3-NOD transgenic mice. CD8{sup +} T cells from 8.3-NOD splenocytes were cultured with IGRP, splenic dendritic cells (SpDCs), TGF-{beta}, and all-trans retinoic acid (ATRA) for 5 days. CD8{sup +} T cells cultured with either IGRP alone or IGRP and SpDCs in the absence of TGF-{beta} and ATRA had low Foxp3{sup +} expression (1.7 {+-} 0.9% and 3.2 {+-} 4.5%, respectively). In contrast, CD8{sup +} T cells induced by exposure to IGRP, SpDCs, TGF-{beta}, and ATRA showed the highest expression of Foxp3{sup +} in IGRP-reactive CD8{sup +} T cells (36.1 {+-} 10.6%), which was approximately 40-fold increase compared with that before induction culture. CD25 expression on CD8{sup +} T cells cultured with IGRP, SpDCs, TGF-{beta}, and ATRA was only 7.42%, whereas CD103 expression was greater than 90%. These CD8{sup +} T cells suppressed the proliferation of diabetogenic CD8{sup +} T cells from 8.3-NOD splenocytes in vitro and completely prevented diabetes onset in NOD-scid mice in cotransfer experiments with diabetogenic splenocytes from NOD mice in vivo. Here we show that exposure to ATRA and TGF-{beta} induces CD8{sup +}Foxp3{sup +} T cells ex vivo, which suppress diabetogenic T cells in vitro and in vivo.

  20. Human brain endothelial cells endeavor to immunoregulate CD8 T cells via PD-1 ligand expression in multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Pittet Camille L

    2011-11-01

    Full Text Available Abstract Background Multiple sclerosis (MS, an inflammatory disease of the central nervous system (CNS, is characterized by blood-brain barrier (BBB disruption and massive infiltration of activated immune cells. Engagement of programmed cell death-1 (PD-1 expressed on activated T cells with its ligands (PD-L1 and PD-L2 suppresses T cell responses. We recently demonstrated in MS lesions elevated PD-L1 expression by glial cells and absence of PD-1 on many infiltrating CD8 T cells. We have now investigated whether human brain endothelial cells (HBECs, which maintain the BBB, can express PD-L1 or PD-L2 and thereby modulate T cells. Methods We used primary cultures of HBECs isolated from non-tumoral CNS tissue either under basal or inflamed conditions. We assessed the expression of PD-L1 and PD-L2 using qPCR and flow cytometry. Human CD8 T cells were isolated from peripheral blood of healthy donors and co-cultured with HBECs. Following co-culture with HBECs, proliferation and cytokine production by human CD8 T cells were measured by flow cytometry whereas transmigration was determined using a well established in vitro model of the BBB. The functional impact of PD-L1 and PD-L2 provided by HBECs was determined using blocking antibodies. We performed immunohistochemistry for the detection of PD-L1 or PD-L2 concurrently with caveolin-1 (a cell specific marker for endothelial cells on post-mortem human brain tissues obtained from MS patients and normal controls. Results Under basal culture conditions, PD-L2 is expressed on HBECs, whilst PD-L1 is not detected. Both ligands are up-regulated under inflammatory conditions. Blocking PD-L1 and PD-L2 leads to increased transmigration and enhanced responses by human CD8 T cells in co-culture assays. Similarly, PD-L1 and PD-L2 blockade significantly increases CD4 T cell transmigration. Brain endothelium in normal tissues and MS lesions does not express detectable PD-L1; in contrast, all blood vessels in normal

  1. Label Free Detection of CD4+ and CD8+ T Cells Using the Optofluidic Ring Resonator

    Directory of Open Access Journals (Sweden)

    John T. Gohring

    2010-06-01

    Full Text Available We have demonstrated label free detection of CD4+ and CD8+ T-Lymphocyte whole cells and CD4+ T-Lymphocyte cell lysis using the optofluidic ring resonator (OFRR sensor. The OFRR sensing platform incorporates microfluidics and photonics in a setup that utilizes small sample volume and achieves a fast detection time. In this work, white blood cells were isolated from healthy blood and the concentrations were adjusted to match T-Lymphocyte levels of individuals infected with HIV. Detection was accomplished by immobilizing CD4 and CD8 antibodies on the inner surface of the OFRR. Sensing results show excellent detection of CD4+ and CD8+ T-Lymphocyte cells at medically significant concentrations with a detection time of approximately 30 minutes. This work will lead to a rapid and low-cost sensing device that can provide a CD4 and CD8 count as a measure of HIV progression.

  2. Location and dynamics of the immunodominant CD8 T cell response to SIVΔnef immunization and SIVmac251 vaginal challenge.

    Directory of Open Access Journals (Sweden)

    Arun K Sasikala-Appukuttan

    Full Text Available Live-attenuated SIV vaccines (LAVs have been the most effective to date in preventing or partially controlling infection by wild-type SIV in non-human primate models of HIV-1 transmission to women acting by mechanisms of protection that are not well understood. To gain insights into mechanisms of protection by LAVs that could aid development of effective vaccines to prevent HIV-1 transmission to women, we used in situ tetramer staining to determine whether increased densities or changes in the local distribution of SIV-specific CD8 T cells correlated with the maturation of SIVΔnef vaccine-induced protection prior to and after intra-vaginal challenge with wild-type SIVmac251. We evaluated the immunodominant Mamu-A1*001:01/Gag (CM9 and Mamu-A1*001:01/Tat (SL8 epitope response in genital and lymphoid tissues, and found that tetramer+ cells were present at all time points examined. In the cervical vaginal tissues, most tetramer+ cells were distributed diffusely throughout the lamina propria or co-localized with other CD8 T cells within lymphoid aggregates. The distribution and densities of the tetramer+ cells at the portal of entry did not correlate with the maturation of protection or change after challenge. Given these findings, we discuss the possibility that changes in other aspects of the immune system, including the quality of the resident population of virus-specific effector CD8 T cells could contribute to maturation of protection, as well as the potential for vaccine strategies that further increase the size and quality of this effector population to prevent HIV-1 transmission.

  3. Identification of cytotoxic T lymphocyte epitopes on swine viruses: multi-epitope design for universal T cell vaccine.

    Directory of Open Access Journals (Sweden)

    Yu-Chieh Liao

    Full Text Available Classical swine fever (CSF, foot-and-mouth disease (FMD and porcine reproductive and respiratory syndrome (PRRS are the primary diseases affecting the pig industry globally. Vaccine induced CD8(+ T cell-mediated immune response might be long-lived and cross-serotype and thus deserve further attention. Although large panels of synthetic overlapping peptides spanning the entire length of the polyproteins of a virus facilitate the detection of cytotoxic T lymphocyte (CTL epitopes, it is an exceedingly costly and cumbersome approach. Alternatively, computational predictions have been proven to be of satisfactory accuracy and are easily performed. Such a method enables the systematic identification of genome-wide CTL epitopes by incorporating epitope prediction tools in analyzing large numbers of viral sequences. In this study, we have implemented an integrated bioinformatics pipeline for the identification of CTL epitopes of swine viruses including the CSF virus (CSFV, FMD virus (FMDV and PRRS virus (PRRSV and assembled these epitopes on a web resource to facilitate vaccine design. Identification of epitopes for cross protections to different subtypes of virus are also reported in this study and may be useful for the development of a universal vaccine against such viral infections among the swine population. The CTL epitopes identified in this study have been evaluated in silico and possibly provide more and wider protection in compared to traditional single-reference vaccine design. The web resource is free and open to all users through http://sb.nhri.org.tw/ICES.

  4. Pleural mesothelial cells promote expansion of IL-17-producing CD8+ T cells in tuberculous pleural effusion.

    Science.gov (United States)

    Li, X; Zhou, Q; Yang, W B; Xiong, X Z; Du, R H; Zhang, J C

    2013-05-01

    IL-17-producing CD8(+) T lymphocytes (Tc17 cells) have recently been detected in many cancers and autoimmune diseases. However, the possible implication of Tc17 cells in tuberculous pleural effusion remains unclarified. In this study, distribution and phenotypic features of Tc17 cells in both tuberculous pleural effusion (TPE) and peripheral blood from patients with tuberculosis were determined. The effects of proinflammatory cytokines and local accessory cells (pleural mesothelial cells) on Tc17 cell expansion were also explored. We found that TPE contained more Tc17 cells than the blood. Compared with IFN-γ-producing CD8(+) T cells, Tc17 cells displayed higher expression of chemokine receptors (CCRs) and lower expression of cytotoxic molecules. In particularly, Tc17 cells in TPE exhibited high expression levels of CCR6, which could migrate in response to CCL20. Furthermore, IL-1β, IL-6, IL-23, or their various combinations could promote Tc17 cell expansion from CD8(+) T cells, whereas the proliferative response of Tc17 cells to above cytokines was lower than that of Th17 cells. Pleural mesothelial cells (PMCs) were able to stimulate Tc17 cell expansion via cell contact in an IL-1β/IL-6/IL-23 independent fashion. Thus this study demonstrates that Tc17 cells marks a subset of non-cytotoxic, CCR6(+) CD8(+) T lymphocytes with low proliferative capacity. The overrepresentation of Tc17 cells in TPE may be due to Tc17 cell expansion stimulated by pleural proinflammatory cytokines and to recruitment of Tc17 cells from peripheral blood. Additionally, PMCs may promote the production of IL-17 by CD8(+) T cells at sites of TPE via cell-cell interactions. PMID:23299924

  5. Intratumoral Interleukin-21 Increases Antitumor Immunity, Tumor-infiltrating CD8(+) T-cell Density and Activity, and Enlarges Draining Lymph Nodes

    DEFF Research Database (Denmark)

    Sondergaard, H.; Galsgaard, E.D.; Bartholomaeussen, M.;

    2010-01-01

    generally benefits the tumor microenvironment and activates tumor-draining LNs. Overall, our data suggest that IL-21 augments CD8(+) T-cell-mediated antitumor immunity through increased proliferation and effector function and acts both on tumor-infiltrating CD8(+) T cells as well as on the draining LNs......, and investigated the mechanisms by which IL-21 enhances CD8(+) T-cell-mediated antitumor immunity. We found that in comparison to subcutaneous administration, IT administration of IL-21 more potently inhibited tumor growth and increased survival. This correlated with increased densities of tumor-infiltrating CD8...

  6. Decreased memory B cells and increased CD8 memory T cells in blood of breastfed children: the generation R study.

    Directory of Open Access Journals (Sweden)

    Michelle A E Jansen

    Full Text Available Breastfeeding provides a protective effect against infectious diseases in infancy. Still, immunological evidence for enhanced adaptive immunity in breastfed children remains inconclusive.To determine whether breastfeeding affects B- and T-cell memory in the first years of life.We performed immunophenotypic analysis on blood samples within a population-based prospective cohort study. Participants included children at 6 months (n=258, 14 months (n=166, 25 months (n=112 and 6 years of age (n=332 with both data on breastfeeding and blood lymphocytes. Total B- and T-cell numbers and their memory subsets were determined with 6-color flow cytometry. Mothers completed questionnaires on breastfeeding when their children were aged 2, 6, and 12 months. Multiple linear regression models with adjustments for potential confounders were performed.Per month continuation of breastfeeding, a 3% (95% CI -6, -1 decrease in CD27+IgM+, a 2% (95 CI % -5, -1 decrease in CD27+IgA+ and a 2% (95% CI -4, -1 decrease in CD27-IgG+ memory B cell numbers were observed at 6 months of age. CD8 T-cell numbers at 6 months of age were 20% (95% CI 3, 37 higher in breastfed than in non-breastfed infants. This was mainly found for central memory CD8 T cells and associated with exposure to breast milk, rather than duration. The same trend was observed at 14 months, but associations disappeared at older ages.Longer breastfeeding is associated with increased CD8 T-cell memory, but not B-cell memory numbers in the first 6 months of life. This transient skewing towards T cell memory might contribute to the protective effect against infectious diseases in infancy.

  7. Serial Assessment of Immune Status by Circulating CD8+ Effector T Cell Frequencies for Posttransplant Infectious Complications

    Directory of Open Access Journals (Sweden)

    Shinji Uemoto

    2008-01-01

    Full Text Available To clarify the role of CD8+ effector T cells for infectious complications, 92 recipients were classified according to the hierarchical clustering of preoperative CD8+CD45 isoforms: Group I was naive, Group II was effector memory, and Group III was effector (E T cell-dominant. The posttransplant infection rates progressively increased from 29% in Group I to 64.3% in Group III recipients. The posttransplant immune status was compared with the pretransplant status, based on the measure (% difference and its graphical form (scatter plot. In Groups I and II, both approaches showed a strong upward deviation from pretransplant status upon posttransplant infection, indicating an enhanced clearance of pathogens. In Group III, in contrast, both approaches showed a clear downward deviation from preoperative status, indicating deficient cytotoxicity. The % E difference and scatter plot can be used as a useful indicator of a posttransplant infectious complication.

  8. Local hyperthermia treatment of tumors induces CD8+ T cell-mediated resistance against distal and secondary tumors

    Science.gov (United States)

    Zhang, Peisheng; Chen, Lei; Baird, Jason R.; Demidenko, Eugene; Turk, Mary Jo; Hoopes, P. Jack; Conejo-Garcia, Jose R.; Fiering, Steven

    2014-01-01

    Combinatorial use of iron oxide nanoparticles (IONPs) and an alternating magnetic filed (AMF) can induce local hyperthermia in tumors in a controlled and uniform manner. Heating B16 primary tumors at 43°C for 30 minutes activated dendritic cells (DCs) and subsequently CD8+ T cells in the draining lymph node (dLN) and conferred resistance against rechallenge with B16 (but not unrelated Lewis Lung carcinoma) given 7 days post hyperthermia on both the primary tumor side and the contralateral side in a CD8+ T cell-dependent manner. Mice with heated primary tumors also resisted rechallenge given 30 days post hyperthermia. Mice with larger heated primary tumors had greater resistance to secondary tumors. No rechallenge resistance occurred when tumors were heated at 45°C. Our results demonstrate the promising potential of local hyperthermia treatment applied to identified tumors in inducing anti-tumor immune responses that reduce the risk of recurrence and metastasis. PMID:24566274

  9. CD8 T-cell responses against cyclin B1 in breast cancer patients with tumors overexpressing p53

    DEFF Research Database (Denmark)

    Sørensen, Rikke Baek; Andersen, Rikke Sick; Svane, Inge Marie;

    2009-01-01

    PURPOSE: This study aimed to examine CD8 T-cell reactivity in breast cancer patients against cyclin B1-derived peptides restricted by the human leukocyte antigen (HLA)-A2 molecule. EXPERIMENTAL DESIGN: Peripheral blood mononuclear cells from 36 breast cancer patients were analyzed by enzyme...... protein in biopsies from the patients by immune histochemistry. Combined data showed that anti-cyclin B1 reactivity was predominantly detected in patients with tumors characterized by elevated expression of p53. Interestingly, no reactivity was detected against six peptides derived from the p53 protein...... CD8 T-cell response against at least one of the peptides; strongest reactivity was detected against the CB9L2 peptide. Because the level of cyclin B1 has been shown to be influenced by the level of p53, which in turn is elevated in cancer cells because of point mutation, we analyzed the level of p53...

  10. Repression of the DNA-binding inhibitor Id3 by Blimp-1 limits CD8+ T cell memory formation

    Science.gov (United States)

    Ji, Yun; Pos, Zoltan; Rao, Mahadev; Klebanoff, Christopher A.; Yu, Zhiya; Sukumar, Madhusudhanan; Reger, Robert N.; Palmer, Douglas C.; Borman, Zachary A.; Muranski, Pawel; Wang, Ena; Schrump, David S.; Marincola, Francesco M.; Restifo, Nicholas P.; Gattinoni, Luca

    2011-01-01

    Blimp-1 is a transcriptional repressor that promotes the differentiation of CD8+ T cells into short-lived KLRG-1+ effector cells (SLEC), but how it operates remains poorly defined. Here we show that Blimp-1 binds and represses the Id3 promoter in SLEC. Repression of Id3 by Blimp-1 was dispensable for SLEC development but limited their capacity to persist as memory cells. Enforced expression of Id3 was sufficient to rescue SLEC survival and enhanced recall responses. Id3 function was mediated in part through inhibition of E2a transcriptional activity and induction of genes regulating genome stability. These findings identify a Blimp-1-Id3-E2a axis as a key molecular switch that determines whether effector CD8+ T cells are programmed to die or enter the memory pool. PMID:22057288

  11. Impaired virus control and severe CD8+ T-cell-mediated immunopathology in chimeric mice deficient in gamma interferon receptor expression on both parenchymal and hematopoietic cells

    DEFF Research Database (Denmark)

    Henrichsen, Pernille; Bartholdy, Christina; Christensen, Jan Pravsgaard;

    2005-01-01

    Bone marrow chimeras were used to determine the cellular target(s) for the antiviral activity of gamma interferon (IFN-gamma). By transfusing such mice with high numbers of naive virus-specific CD8(+) T cells, a system was created in which the majority of virus-specific CD8(+) T cells would be...

  12. TIL therapy broadens the tumor-reactive CD8(+) T cell compartment in melanoma patients

    DEFF Research Database (Denmark)

    Kvistborg, Pia; Shu, Chengyi Jenny; Heemskerk, Bianca;

    2012-01-01

    There is strong evidence that both adoptive T cell transfer and T cell checkpoint blockade can lead to regression of human melanoma. However, little data are available on the effect of these cancer therapies on the tumor-reactive T cell compartment. To address this issue we have profiled therapy-...

  13. Clinical, immunological and treatment-related factors associated with normalised CD4+/CD8+ T-cell ratio: effect of naïve and memory T-cell subsets.

    LENUS (Irish Health Repository)

    Tinago, Willard

    2014-01-01

    Although effective antiretroviral therapy(ART) increases CD4+ T-cell count, responses to ART vary considerably and only a minority of patients normalise their CD4+\\/CD8+ ratio. Although retention of naïve CD4+ T-cells is thought to predict better immune responses, relationships between CD4+ and CD8+ T-cell subsets and CD4+\\/CD8+ ratio have not been well described.

  14. Generalized Liver- and Blood-Derived CD8+ T-Cell Impairment in Response to Cytokines in Chronic Hepatitis C Virus Infection.

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    Stephanie C Burke Schinkel

    Full Text Available Generalized CD8+ T-cell impairment in chronic hepatitis C virus (HCV infection and the contribution of liver-infiltrating CD8+ T-cells to the immunopathogenesis of this infection remain poorly understood. It is hypothesized that this impairment is partially due to reduced CD8+ T-cell activity in response to cytokines such as IL-7, particularly within the liver. To investigate this, the phenotype and cytokine responsiveness of blood- and liver-derived CD8+ T-cells from healthy controls and individuals with HCV infection were compared. In blood, IL-7 receptor α (CD127 expression on bulk CD8+ T-cells in HCV infection was no different than controls yet was lower on central memory T-cells, and there were fewer naïve cells. IL-7-induced signalling through phosphorylated STAT5 was lower in HCV infection than in controls, and differed between CD8+ T-cell subsets. Production of Bcl-2 following IL-7 stimulation was also lower in HCV infection and inversely related to the degree of liver fibrosis. In liver-derived CD8+ T-cells, STAT5 activation could not be increased with cytokine stimulation and basal Bcl-2 levels of liver-derived CD8+ T-cells were lower than blood-derived counterparts in HCV infection. Therefore, generalized CD8+ T-cell impairment in HCV infection is characterized, in part, by impaired IL-7-mediated signalling and survival, independent of CD127 expression. This impairment is more pronounced in the liver and may be associated with an increased potential for apoptosis. This generalized CD8+ T-cell impairment represents an important immune dysfunction in chronic HCV infection that may alter patient health.

  15. Vaccination with an adenoviral vector encoding the tumor antigen directly linked to invariant chain induces potent CD4(+) T-cell-independent CD8(+) T-cell-mediated tumor control

    DEFF Research Database (Denmark)

    Sorensen, Maria R; Holst, Peter J; Pircher, Hanspeter;

    2009-01-01

    of the vaccine antigen to invariant chain (Ii). To evaluate this strategy we used a mouse model, in which an immunodominant epitope (GP33) of the LCMV glycoprotein (GP) represents the tumor-associated neoantigen. Prophylactic vaccination of C57BL/6 mice with a replication-deficient human adenovirus 5 vector...... vaccination with adenovirus expressing GP alone (Ad-GP), or GP and Ii unlinked (Ad-GP+Ii). Ad-Ii-GP- induced tumor control depended on an improved generation of the tumor-associated neoantigen-specific CD8(+) T-cell response and was independent of CD4(+) T cells. IFN-gamma was shown to be a key player during...

  16. Development of Virus-Specific CD4+ and CD8+ Regulatory T Cells Induced by Human Herpesvirus 6 Infection

    OpenAIRE

    Wang, Fang; Chi, Jing; Peng, Guangyong; Zhou, Feng; Wang, Jinfeng; Li, Lingyun; Feng, Dongju; Xie, Fangyi; Gu, Bin; Qin, Jian; CHEN, YUN; Yao, Kun

    2014-01-01

    Human herpesvirus 6 (HHV-6) is an important immunosuppressive and immunomodulatory virus. The mechanisms by which HHV-6 establishes latency and immunosuppression in its host are not well understood. Here we characterized HHV-6-specific T cells in peripheral blood mononuclear cells (PBMCs) from HHV-6-infected donors. Our results showed that HHV-6 infection could induce both CD4+ and CD8+ HHV-6-specific regulatory T (Treg) cells. These HHV-6-specific Treg cells had potent suppressive activity a...

  17. Genetically Attenuated Plasmodium berghei Liver Stages Persist and Elicit Sterile Protection Primarily via CD8 T Cells

    OpenAIRE

    Mueller, Ann-Kristin; Deckert, Martina; Heiss, Kirsten; Goetz, Kristin; Matuschewski, Kai; Schlüter, Dirk

    2007-01-01

    Live-attenuated Plasmodium liver stages remain the only experimental model that confers complete sterile protection against malaria. Irradiation-attenuated Plasmodium parasites mediate protection primarily by CD8 T cells. In contrast, it is unknown how genetically attenuated liver stage parasites provide protection. Here, we show that immunization with uis3(−) sporozoites does not cause breakthrough infection in T and B-cell-deficient rag1−/− and IFN-γ−/− mice. However, protection was abolish...

  18. HIV Replication Is Not Controlled by CD8+ T Cells during the Acute Phase of the Infection in Humanized Mice

    OpenAIRE

    Petit, Nicolas Y.; Lambert-Niclot, Sidonie; Marcelin, Anne-Geneviève; Garcia, Sylvie; Marodon, Gilles

    2015-01-01

    International audience HIV replication follows a well-defined pattern during the acute phase of the infection in humans. After reaching a peak during the first few weeks after infection, viral replication resolves to a set-point thereafter. There are still uncertainties regarding the contribution of CD8 + T cells in establishing this set-point. An alternative explanation, supported by in silico modeling, would imply that viral replication is limited by the number of available targets for i...

  19. CD8+ T cells Mediate RAS-induced Psoriasis-like Skin Inflammation Through IFN-γ

    OpenAIRE

    Gunderson, Andrew J.; Mohammed, Javed; Horvath, Frank; Podolsky, Michael, J.; Anderson, Cherie; Glick, Adam B.

    2012-01-01

    The RAS signaling pathway is constitutively activated in psoriatic keratinocytes. We expressed activated H-RASV12G in suprabasal keratinocytes of adult mice and observed rapid development of a psoriasis-like skin phenotype characterized by basal keratinocyte hyperproliferation, acanthosis, hyperkeratosis, intraepidermal neutrophil microabscesses and increased Th1/Th17 and Tc1/Tc17 skin infiltration. The majority of skin infiltrating CD8+ T cells co-expressed IFN-γ and IL-17A. When RAS was exp...

  20. Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity

    Directory of Open Access Journals (Sweden)

    II Kim Jae

    2010-10-01

    Full Text Available Abstract Background Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through in vitro and in vivo studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism. Methods In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB. Proliferation assay based on [3H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8+ T cell was compared by JAM test. Results Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight and histological analysis of the lung metastasis (gross analysis and histological staining. Reduced expression of Cox-2 (mRNA and protein from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8+ T cells by increasing the proliferation capacity and their cytolytic activity. Conclusions Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8+ T cells.

  1. CCR5 plays a key role in the early memory CD8+ T cell response to respiratory virus infections

    OpenAIRE

    Kohlmeier, Jacob E.; Miller, Shannon C.; Smith, Joanna; Lu, Bao; Gerard, Craig; Cookenham, Tres; Roberts, Alan D.; Woodland, David L

    2008-01-01

    Innate recognition of invading pathogens in peripheral tissues results in the recruitment of circulating memory CD8+ T cells to sites of localized inflammation during the early phase of a recall response. However, the mechanisms that control the rapid recruitment of these cells to peripheral sites are poorly understood, particularly in relation to influenza and parainfluenza infections of the respiratory tract. In this study, we demonstrate a crucial role for CCR5 in the accelerated recruitme...

  2. Hesperidin Inhibits Inflammatory Response Induced by Aeromonas hydrophila Infection and Alters CD4+/CD8+ T Cell Ratio

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    Abdelaziz S. A. Abuelsaad

    2014-01-01

    Full Text Available Background. Aeromonas hydrophila is an opportunistic bacterial pathogen that is associated with a number of human diseases. Hesperidin (HES has been reported to exert antioxidant and anti-inflammatory activities. Objectives. The aim of this study was to investigate the potential effect of HES treatment on inflammatory response induced by A. hydrophila infection in murine. Methods. A. hydrophila-infected mice were treated with HES at 250 mg/kg b.wt./week for 4 consecutive weeks. Phagocytosis, reactive oxygen species production, CD4+/CD8+ T cell ratio, and CD14 expression on intestinal infiltrating monocytes were evaluated. The expression of E-selectin and intercellular adhesion molecule 1 on stimulated HUVECs and RAW macrophage was evaluated. Results. Percentage of CD4+ T cells in the intestinal tissues of infected treated mice was highly significantly increased; however, phagocytic index, ROS production, CD8+ T cells percentage, and CD14 expression on monocytes were significantly reduced. On the other hand, HES significantly inhibited A-LPS- and A-ECP-induced E-selectin and ICAM-1 expression on HUVECs and ICAM-1 expression on RAW macrophage. Conclusion. Present data indicated that HES has a potential role in the suppression of inflammatory response induced by A. hydrophila toxins through downmodulation of ROS production and CD14 and adhesion molecules expression, as well as increase of CD4+/CD8+ cell ratio.

  3. Tomatine Adjuvantation of Protective Immunity to a Major Pre-erythrocytic Vaccine Candidate of Malaria is Mediated via CD8+ T Cell Release of IFN-γ

    Directory of Open Access Journals (Sweden)

    Karen G. Heal

    2010-01-01

    Full Text Available The glycoalkaloid tomatine, derived from the wild tomato, can act as a powerful adjuvant to elicit an antigen-specific cell-mediated immune response to the circumsporozoite (CS protein, a major pre-erythrocytic stage malaria vaccine candidate antigen. Using a defined MHC-class-I-restricted CS epitope in a Plasmodium berghei rodent model, antigen-specific cytotoxic T lymphocyte activity and IFN-γ secretion ex vivo were both significantly enhanced compared to responses detected from similarly stimulated splenocytes from naive and tomatine-saline-immunized mice. Further, through lymphocyte depletion it is demonstrated that antigen-specific IFN-γ is produced exclusively by the CD8+ T cell subset. We conclude that the processing of the P. berghei CS peptide as an exogenous antigen and its presentation via MHC class I molecules to CD8+ T cells leads to an immune response that is an in vitro correlate of protection against pre-erythrocytic malaria. Further characterization of tomatine as an adjuvant in malaria vaccine development is indicated.

  4. HIV-specific CD8~+ T cell responses to HXB2 Gag and Nef peptide pools in Chinese HIV/AIDS patients

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    HXB2 is primarily used as a template strain in developing HIV vaccines in Europe and the US. However,it is not yet known whether the strain can induce strong HIV-specific CD8+ T cell responses in Chinese HIV/AIDS patients. In the present study,two groups of subjects were investigated:9 AIDS patients and 7 long-term nonprogressors (LTNPs). HIV-specific CD8+ T cell responses were examined in all patients through the ELISPOT assay. CD4+ T cell counts,CD8+ T cell counts,viral load and HIV subtype of each patient were also measured. Thailand B virus strain was identified among all the patients. The breadth and magnitude of HIV-specific CD8+ T cell responses in the LTNPs group are greater than those in the AIDS group (P<0.01). There is a positive correlation between magnitude of HIV-specific CD8+ T cell responses and CD4+ T cells,and a negative correlation between HIV-specific CD8+ T cell responses and mean viral load. In summary,the HIV-specific CD8+ T cell responses to the HXB2 Gag and Nef peptide pools are considerable in Chinese HIV/AIDS patients infected with Thailand B virus strain. HIV-1 vaccines based on HXB2 strain that can induce extensive immunity may be helpful for Chinese.