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Sample records for cd8 epitope display

  1. Dengue virus-reactive CD8+ T cells display quantitative and qualitative differences in their response to variant epitopes of heterologous viral serotypes.

    PubMed

    Bashyam, Hema S; Green, Sharone; Rothman, Alan L

    2006-03-01

    Reactivation of serotype cross-reactive CD8+ memory T lymphocytes is thought to contribute to the immunopathogenesis of dengue disease during secondary infection by a heterologous serotype. Using cytokine flow cytometry, we have defined four novel HLA-A*02-restricted dengue viral epitopes recognized by up to 1.5% of circulating CD8+ T cells in four donors after primary vaccination. All four donors had the highest cytokine response to the epitope NS4b 2353. We also studied the effect of sequence differences in heterologous dengue serotypes on dengue-reactive CD8+ memory T cell cytokine and proliferative responses. The D3 variant of a different NS4b epitope 2423 and the D2 variant of the NS4a epitope 2148 induced the largest cytokine response, compared with their respective heterologous sequences in all donors regardless of the primary vaccination serotype. Stimulation with variant peptides also altered the relative frequencies of the various subsets of cells that expressed IFN-gamma, TNF-alpha, MIP-1beta, and combinations of these cytokines. These results indicate that the prior infection history of the individual as well as the serotypes of the primary and heterologous secondary viruses influence the nature of the secondary response. These differences in the effector functions of serotype cross-reactive memory T cells induced by heterologous variant epitopes, which are both quantitative and qualitative, may contribute to the clinical outcome of secondary dengue infection.

  2. CD8 epitope escape and reversion in acute HCV infection.

    PubMed

    Timm, Joerg; Lauer, Georg M; Kavanagh, Daniel G; Sheridan, Isabelle; Kim, Arthur Y; Lucas, Michaela; Pillay, Thillagavathie; Ouchi, Kei; Reyor, Laura L; Schulze zur Wiesch, Julian; Gandhi, Rajesh T; Chung, Raymond T; Bhardwaj, Nina; Klenerman, Paul; Walker, Bruce D; Allen, Todd M

    2004-12-20

    In the setting of acute hepatitis C virus (HCV) infection, robust HCV-specific CD8+ cytotoxic T lymphocyte (CTL) responses are associated with initial control of viremia. Despite these responses, 70-80% of individuals develop persistent infection. Although viral escape from CD8 responses has been illustrated in the chimpanzee model of HCV infection, the effect of CD8 selection pressure on viral evolution and containment in acute HCV infection in humans remains unclear. Here, we examined viral evolution in an immunodominant human histocompatibility leukocyte antigen (HLA)-B8-restricted NS3 epitope in subjects with acute HCV infection. Development of mutations within the epitope coincided with loss of strong ex vivo tetramer and interferon gamma enzyme-linked immunospot responses, and endogenous expression of variant NS3 sequences suggested that the selected mutations altered processing and presentation of the variant epitope. Analysis of NS3 sequences from 30 additional chronic HCV-infected subjects revealed a strong association between sequence variation within this region and expression of HLA-B8, supporting reproducible allele-specific selection pressures at the population level. Interestingly, transmission of an HLA-B8-associated escape mutation to an HLA-B8 negative subject resulted in rapid reversion of the mutation. Together, these data indicate that viral escape from CD8+ T cell responses occurs during human HCV infection and that acute immune selection pressure is of sufficient magnitude to influence HCV evolution.

  3. Dengue virus-infected human dendritic cells reveal hierarchies of naturally expressed novel NS3 CD8 T cell epitopes.

    PubMed

    Piazza, P; Campbell, D; Marques, E; Hildebrand, W H; Buchli, R; Mailliard, R; Rinaldo, C R

    2014-09-01

    Detailed knowledge of dengue virus (DENV) cell-mediated immunity is limited. In this study we characterize CD8(+) T lymphocytes recognizing three novel and two known non-structural protein 3 peptide epitopes in DENV-infected dendritic cells. Three epitopes displayed high conservation (75-100%), compared to the others (0-50%). A hierarchy ranking based on magnitude and polyfunctionality of the antigen-specific response showed that dominant epitopes were both highly conserved and cross-reactive against multiple DENV serotypes. These results are relevant to DENV pathogenesis and vaccine design.

  4. HLA-B*35-Restricted CD8+-T-Cell Epitope in Mycobacterium tuberculosis Rv2903c

    PubMed Central

    Klein, Michèl R.; Hammond, Abdulrahman S.; Smith, Steve M.; Jaye, Assan; Lukey, Pauline T.; McAdam, Keith P. W. J.

    2002-01-01

    Few human CD8+ T-cell epitopes in mycobacterial antigens have been described to date. Here we have identified a novel HLA-B*35-restricted CD8+ T-cell epitope in Mycobacterium tuberculosis Rv2903c based on a reverse immunogenetics approach. Peptide-specific CD8 T cells were able to kill M. tuberculosis-infected macrophages and produce gamma interferon and tumor necrosis factor alpha. PMID:11796635

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

    PubMed Central

    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

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

    PubMed

    Rosendahl Huber, Sietske K; Luimstra, Jolien J; 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.

  7. Mycobacterium tuberculosis genome-wide screen exposes multiple CD8+ T cell epitopes

    PubMed Central

    Hammond, A S; Klein, M R; Corrah, T; Fox, A; Jaye, A; McAdam, K P; Brookes, R H

    2005-01-01

    Mounting evidence suggests human leucocyte antigen (HLA) class I-restricted CD8+ T cells play a role in protective immunity against tuberculosis yet relatively few epitopes specific for the causative organism, Mycobacterium tuberculosis, are reported. Here a total genome-wide screen of M. tuberculosis was used to identify putative HLA-B*3501 T cell epitopes. Of 479 predicted epitopes, 13 with the highest score were synthesized and used to restimulate lymphocytes from naturally exposed HLA-B*3501 healthy individuals in cultured and ex vivo enzyme-linked immunospot (ELISPOT) assays for interferon (IFN)-γ. All 13 peptides elicited a response that varied considerably between individuals. For three peptides CD8+ T cell lines were expanded and four of the 13 were recognized permissively through the HLA-B7 supertype family. Although further testing is required we show the genome-wide screen to be feasible for the identification of unknown mycobacterial antigens involved in immunity against natural infection. While the mechanisms of protective immunity against M. tuberculosis infection remain unclear, conventional class I-restricted CD8+ T cell responses appear to be widespread throughout the genome. PMID:15762882

  8. TCR contact residue hydrophobicity is a hallmark of immunogenic CD8+ T cell epitopes

    PubMed Central

    Chowell, Diego; Krishna, Sri; Cocita, Clément; Shu, Jack; Tan, Xuefang; Greenberg, Philip D.; Klavinskis, Linda S.; Blattman, Joseph N.; Anderson, Karen S.

    2015-01-01

    Despite the availability of major histocompatibility complex (MHC)-binding peptide prediction algorithms, the development of T-cell vaccines against pathogen and tumor antigens remains challenged by inefficient identification of immunogenic epitopes. CD8+ T cells must distinguish immunogenic epitopes from nonimmunogenic self peptides to respond effectively against an antigen without endangering the viability of the host. Because this discrimination is fundamental to our understanding of immune recognition and critical for rational vaccine design, we interrogated the biochemical properties of 9,888 MHC class I peptides. We identified a strong bias toward hydrophobic amino acids at T-cell receptor contact residues within immunogenic epitopes of MHC allomorphs, which permitted us to develop and train a hydrophobicity-based artificial neural network (ANN-Hydro) to predict immunogenic epitopes. The immunogenicity model was validated in a blinded in vivo overlapping epitope discovery study of 364 peptides from three HIV-1 Gag protein variants. Applying the ANN-Hydro model on existing peptide-MHC algorithms consistently reduced the number of candidate peptides across multiple antigens and may provide a correlate with immunodominance. Hydrophobicity of TCR contact residues is a hallmark of immunogenic epitopes and marks a step toward eliminating the need for empirical epitope testing for vaccine development. PMID:25831525

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

    PubMed

    Shorter, Shayla K; Schnell, Frederick J; McMaster, Sean R; Pinelli, David F; Andargachew, Rakieb; Evavold, Brian D

    2016-01-01

    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.

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

    PubMed Central

    Shorter, Shayla K.; Schnell, Frederick J.; McMaster, Sean R.; Pinelli, David F.; Andargachew, Rakieb; Evavold, Brian D.

    2016-01-01

    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. PMID:26915099

  11. Subdominant CD8 T-cell epitopes account for protection against cytomegalovirus independent of immunodomination.

    PubMed

    Holtappels, Rafaela; Simon, Christian O; Munks, Michael W; Thomas, Doris; Deegen, Petra; Kühnapfel, Birgit; Däubner, Torsten; Emde, Simone F; Podlech, Jürgen; Grzimek, Natascha K A; Oehrlein-Karpi, Silke A; Hill, Ann B; Reddehase, Matthias J

    2008-06-01

    Cytomegalovirus (CMV) infection continues to be a complication in recipients of hematopoietic stem cell transplantation (HSCT). Preexisting donor immunity is recognized as a favorable prognostic factor for the reconstitution of protective antiviral immunity mediated primarily by CD8 T cells. Furthermore, adoptive transfer of CMV-specific memory CD8 T (CD8-T(M)) cells is a therapeutic option for preventing CMV disease in HSCT recipients. Given the different CMV infection histories of donor and recipient, a problem may arise from an antigenic mismatch between the CMV variant that has primed donor immunity and the CMV variant acquired by the recipient. Here, we have used the BALB/c mouse model of CMV infection in the immunocompromised host to evaluate the importance of donor-recipient CMV matching in immundominant epitopes (IDEs). For this, we generated the murine CMV (mCMV) recombinant virus mCMV-DeltaIDE, in which the two memory repertoire IDEs, the IE1-derived peptide 168-YPHFMPTNL-176 presented by the major histocompatibility complex class I (MHC-I) molecule L(d) and the m164-derived peptide 257-AGPPRYSRI-265 presented by the MHC-I molecule D(d), are both functionally deleted. Upon adoptive transfer, polyclonal donor CD8-T(M) cells primed by mCMV-DeltaIDE and the corresponding revertant virus mCMV-revDeltaIDE controlled infection of immunocompromised recipients with comparable efficacy and regardless of whether or not IDEs were presented in the recipients. Importantly, CD8-T(M) cells primed under conditions of immunodomination by IDEs protected recipients in which IDEs were absent. This shows that protection does not depend on compensatory expansion of non-IDE-specific CD8-T(M) cells liberated from immunodomination by the deletion of IDEs. We conclude that protection is, rather, based on the collective antiviral potential of non-IDEs independent of the presence or absence of IDE-mediated immunodomination.

  12. Identification of Zika virus epitopes reveals immunodominant and protective roles for dengue virus cross-reactive CD8(+) T cells.

    PubMed

    Wen, Jinsheng; Tang, William Weihao; Sheets, Nicholas; Ellison, Julia; Sette, Alessandro; Kim, Kenneth; Shresta, Sujan

    2017-03-13

    CD8(+) T cells play an important role in controlling Flavivirus infection, including Zika virus (ZIKV). Here, we have identified 25 HLA-B*0702-restricted epitopes and 1 HLA-A*0101-restricted epitope using interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) and intracellular cytokine staining (ICS) in ZIKV-infected IFN-α/β receptor-deficient HLA transgenic mice. The cross-reactivity of ZIKV epitopes to dengue virus (DENV) was tested using IFN-γ-ELISPOT and IFN-γ-ICS on CD8(+) T cells from DENV-infected mice, and five cross-reactive HLA-B*0702-binding peptides were identified by both assays. ZIKV/DENV cross-reactive CD8(+) T cells in DENV-immune mice expanded post ZIKV challenge and dominated in the subsequent CD8(+) T cell response. ZIKV challenge following immunization of mice with ZIKV-specific and ZIKV/DENV cross-reactive epitopes elicited CD8(+) T cell responses that reduced infectious ZIKV levels, and CD8(+) T cell depletions confirmed that CD8(+) T cells mediated this protection. These results identify ZIKV-specific and ZIKV/DENV cross-reactive epitopes and demonstrate both an altered immunodominance pattern in the DENV-immune setting relative to naive, as well as a protective role for epitope-specific CD8(+) T cells against ZIKV. These results have important implications for ZIKV vaccine development and provide a mouse model for evaluating anti-ZIKV CD8(+) T cell responses of human relevance.

  13. Apoptotic Epitope-Specific CD8+ T Cells and Interferon Signaling Intersect in Chronic Hepatitis C Virus Infection.

    PubMed

    Martini, Helene; Citro, Alessandra; Martire, Carmela; D'Ettorre, Gabriella; Labbadia, Giancarlo; Accapezzato, Daniele; Piconese, Silvia; De Marzio, Paolo; Cavallari, Eugenio N; Calvo, Ludovica; Rizzo, Fabiana; Severa, Martina; Coccia, Eliana M; Grazi, Gian Luca; Di Filippo, Simona; Sidney, John; Vullo, Vincenzo; Sette, Alessandro; Barnaba, Vincenzo

    2016-02-15

    CD8(+) T cells specific to caspase-cleaved antigens derived from apoptotic T cells represent a principal player in chronic immune activation. Here, we found that both apoptotic epitope-specific and hepatitis C virus (HCV)-specific CD8(+) T cells were mostly confined within the effector memory (EM) or terminally differentiated EM CD45RA(+) cell subsets expressing a dysfunctional T-helper 1-like signature program in chronic HCV infection. However, apoptotic epitope-specific CD8(+) T cells produced tumor necrosis factor α and interleukin 2 at the intrahepatic level significantly more than HCV-specific CD8(+) T cells, despite both populations expressing high levels of programmed death 1 receptor. Contextually, only apoptotic epitope-specific CD8(+) T cells correlated with both interferon-stimulated gene levels in T cells and hepatic fibrosis score. Together, these data suggest that, compared with HCV-specific CD8(+) T cells, apoptotic epitope-specific CD8(+) T cells can better sustain chronic immune activation, owing to their capacity to produce tumor necrosis factor α, and exhibit greater resistance to inhibitory signals during chronic HCV infection.

  14. Subdominant/Cryptic CD8 T Cell Epitopes Contribute to Resistance against Experimental Infection with a Human Protozoan Parasite

    PubMed Central

    Dominguez, Mariana R.; Silveira, Eduardo L. V.; de Vasconcelos, José Ronnie C.; de Alencar, Bruna C. G.; Machado, Alexandre V.; Bruna-Romero, Oscar; Gazzinelli, Ricardo T.; Rodrigues, Mauricio M.

    2011-01-01

    During adaptive immune response, pathogen-specific CD8+ T cells recognize preferentially a small number of epitopes, a phenomenon known as immunodominance. Its biological implications during natural or vaccine-induced immune responses are still unclear. Earlier, we have shown that during experimental infection, the human intracellular pathogen Trypanosoma cruzi restricts the repertoire of CD8+ T cells generating strong immunodominance. We hypothesized that this phenomenon could be a mechanism used by the parasite to reduce the breath and magnitude of the immune response, favoring parasitism, and thus that artificially broadening the T cell repertoire could favor the host. Here, we confirmed our previous observation by showing that CD8+ T cells of H-2a infected mice recognized a single epitope of an immunodominant antigen of the trans-sialidase super-family. In sharp contrast, CD8+ T cells from mice immunized with recombinant genetic vaccines (plasmid DNA and adenovirus) expressing this same T. cruzi antigen recognized, in addition to the immunodominant epitope, two other subdominant epitopes. This unexpected observation allowed us to test the protective role of the immune response to subdominant epitopes. This was accomplished by genetic vaccination of mice with mutated genes that did not express a functional immunodominant epitope. We found that these mice developed immune responses directed solely to the subdominant/cryptic CD8 T cell epitopes and a significant degree of protective immunity against infection mediated by CD8+ T cells. We concluded that artificially broadening the T cell repertoire contributes to host resistance against infection, a finding that has implications for the host-parasite relationship and vaccine development. PMID:21779365

  15. Identification and immunogenicity of two new HLA-A*0201-restricted CD8+ T-cell epitopes on dengue NS1 protein.

    PubMed

    Tian, Jiang; Zeng, Gucheng; Pang, Xianwu; Liang, Mifang; Zhou, Junmei; Fang, Danyun; Liu, Yan; Li, Dexin; Jiang, Lifang

    2012-04-01

    Immunopathogenesis of dengue virus (DEN) infection remains poorly studied. Identification and characterization of human CD8(+) T-cell epitopes on DEN are necessary for a better understanding of the immunopathogenesis of dengue infection and would facilitate the development of immunotherapy and vaccines to protect from dengue infection. Here, we identified two new HLA-A*0201-restricted CD8(+) T-cell epitopes, DEN-4 NS1(990)(-998) and DEN-4 NS1(997)(-1005) that are conserved in three or four major DEN serotypes, respectively. Unexpectedly, we found that immunization of HLA-A*0201 transgenic mice with DEN-4 NS1(990)(-998) or DEN-4 NS1(997)(-1005) epitope peptide induced de novo synthesis of tumor necrosis factor (TNF)-α and IFN-γ, two important pro-inflammatory molecules that are hard to be detected directly without in vitro antigenic re-stimulation. Importantly, we demonstrated that CD8(+) T cells specifically activated by DEN-4 NS1(990)(-998) or DEN-4 NS1(997)(-1005) epitope peptide induced de novo synthesis of perforin. Furthermore, we observed that DEN-4 NS1(990)(-998) or DEN-4 NS1(997)(-1005)-specific CD8(+) T cells capable of producing large amounts of perforin, TNF-α and IFN-γ preferentially displayed CD27(+)CD45RA(-), but not CD27(-)CD45RA(+), phenotypes. This study, therefore, suggested the importance of synergistic effects of pro-inflammatory cytokines and cytotoxic molecules which were produced by dengue-specific CD8(+) T cells in immunopathogenesis or anti-dengue immunity during dengue infection.

  16. Identification of a dengue virus-specific HLA-A*0201-restricted CD8+ T cell epitope.

    PubMed

    Wen, Jinsheng; Duan, Zhiliang; Jiang, Lifang

    2010-04-01

    In this study, a combination of epitope-prediction programs and in vitro assays was used to identify dengue virus (DENV)-specific CD8(+) T cell epitopes. Peripheral blood mononuclear cells (PBMCs) isolated from patients who recovered from dengue fever were stimulated with candidate epitope peptides derived from DENV, which were predicted by using SYFPEITHI and RANKpep epitope-prediction programs. The IFN-gamma ELISpot results and the results of intracellular staining of IFN-gamma showed that peptides NS4b_40 (TLYAVATTI), E_256 (QEGAMHTAL), NS3_205 (LPAIVREAI), NS5_210 (SRNSTHEMY), and NS3_207 (AIVREAIKR) could induce the recall response of CD8(+) T cells. Furthermore, the results of the MHC-peptide complex stabilization assay revealed that peptide NS4b_40 (TLYAVATTI) has a high affinity for HLA-A*0201 molecules. The IFN-gamma ELISpot results and staining of intracellular IFN-gamma confirmed that this peptide could induce high-level CD8(+) T cell response in HLA-A*0201 positive PBMCs. Peptide NS4b_40 (TLYAVATTI) was identified as a novel DENV-specific HLA-A*0201-restricted CD8(+) T cell epitope.

  17. Human TCR-αβ+ CD4− CD8− T Cells Can Derive from CD8+ T Cells and Display an Inflammatory Effector Phenotype1

    PubMed Central

    Crispín, José C.; Tsokos, George C.

    2010-01-01

    The origin and function of human double negative (DN) TCR-αβ+ T cells is unknown. They are thought to contribute to the pathogenesis of systemic lupus erythematosus because they expand and accumulate in inflamed organs. In this study, we provide evidence that human TCR-αβ+ CD4− CD8− DN T cells can derive from activated CD8+ T cells. Freshly isolated TCR-αβ+ DN T cells display a distinct gene expression and cytokine production profile. DN cells isolated from peripheral blood as well as DN cells derived in vitro from CD8+ T cells produce a defined array of proinflammatory mediators that includes IL-1β, IL-17, IFN-γ, CXCL3, and CXCL2. These results indicate that, upon activation, CD8+ T cells have the capacity to acquire a distinct phenotype that grants them inflammatory capacity. PMID:19734235

  18. Cross-genotype-reactivity of the immunodominant HCV CD8 T-cell epitope NS3-1073.

    PubMed

    Fytili, P; Dalekos, G N; Schlaphoff, V; Suneetha, P V; Sarrazin, C; Zauner, W; Zachou, K; Berg, T; Manns, M P; Klade, C S; Cornberg, M; Wedemeyer, H

    2008-07-23

    The HCV-specific HLA-A2-restricted NS3(1073) epitope is one of the most frequently recognized epitopes in hepatitis C. NS3(1073)-specific T-cell responses are associated with clearance of acute HCV-infection. Therefore this epitope is an interesting candidate for a HCV-peptide vaccine. However, heterogeneity between genotypes and mutations in the epitope has to be considered as an obstacle. We here identified 34 naturally occurring NS3(1073)-variants, as compared with the wild type genotype-1 variants (CVNGVCWTV/CINGVCWTV) by sequencing sera of 251 Greek and German patients and searching for published HCV-genomes. The frequency of variants among genotype-1 patients was 10%. Importantly, HLA-A2 binding was reduced only in 3 genotype 1 mutants while all non-genotype 1 variants showed strong HLA-A2-binding. By screening 28 variants in ELISPOT assays from T cell lines we could demonstrate that HCV-NS3(1073)-wild-type-specific T-cells displayed cross-genotype-reactivity, in particular against genotypes 4-6 variants. However, single aa changes within the TCR-binding domain completely abolished recognition even in case of conservative aa exchanges within genotype-1. NS3(1073)-specific T-cell lines from recovered, chronically infected, and HCV-negative individuals showed no major difference in the pattern of cross-recognition although the proliferation of NS3(1073)-specific T-cells differed significantly between the groups. Importantly, the recognition pattern against the 28 variants was also identical directly ex vivo in a patient with acute HCV infection and a healthy volunteer vaccinated with the peptide vaccine IC41 containing the NS3(1073)-wild-type peptide. Thus, partial cross-genotype recognition of HCV NS3(1073)-specific CD8 T cells is possible; however, even single aa exchanges can significantly limit the potential efficacy of vaccines containing the NS3(1073)-wild-type peptide.

  19. Epitope-specific CD8+ T cell kinetics rather than viral variability determine the timing of immune escape in simian immunodeficiency virus infection.

    PubMed

    Martyushev, Alexey P; Petravic, Janka; Grimm, Andrew J; Alinejad-Rokny, Hamid; Gooneratne, Shayarana L; Reece, Jeanette C; Cromer, Deborah; Kent, Stephen J; Davenport, Miles P

    2015-05-01

    CD8(+) T cells are important for the control of chronic HIV infection. However, the virus rapidly acquires "escape mutations" that reduce CD8(+) T cell recognition and viral control. The timing of when immune escape occurs at a given epitope varies widely among patients and also among different epitopes within a patient. The strength of the CD8(+) T cell response, as well as mutation rates, patterns of particular amino acids undergoing escape, and growth rates of escape mutants, may affect when escape occurs. In this study, we analyze the epitope-specific CD8(+) T cells in 25 SIV-infected pigtail macaques responding to three SIV epitopes. Two epitopes showed a variable escape pattern and one had a highly monomorphic escape pattern. Despite very different patterns, immune escape occurs with a similar delay of on average 18 d after the epitope-specific CD8(+) T cells reach 0.5% of total CD8(+) T cells. We find that the most delayed escape occurs in one of the highly variable epitopes, and that this is associated with a delay in the epitope-specific CD8(+) T cells responding to this epitope. When we analyzed the kinetics of immune escape, we found that multiple escape mutants emerge simultaneously during the escape, implying that a diverse population of potential escape mutants is present during immune selection. Our results suggest that the conservation or variability of an epitope does not appear to affect the timing of immune escape in SIV. Instead, timing of escape is largely determined by the kinetics of epitope-specific CD8(+) T cells.

  20. Modulation of CD8+ T cell responses to AAV vectors with IgG-derived MHC class II epitopes.

    PubMed

    Hui, Daniel J; Basner-Tschakarjan, Etiena; Chen, Yifeng; Davidson, Robert J; Buchlis, George; Yazicioglu, Mustafa; Pien, Gary C; Finn, Jonathan D; Haurigot, Virginia; Tai, Alex; Scott, David W; Cousens, Leslie P; Zhou, Shangzhen; De Groot, Anne S; Mingozzi, Federico

    2013-09-01

    Immune responses directed against viral capsid proteins constitute a main safety concern in the use of adeno-associated virus (AAV) as gene transfer vectors in humans. Pharmacological immunosuppression has been proposed as a solution to the problem; however, the approach suffers from several potential limitations. Using MHC class II epitopes initially identified within human IgG, named Tregitopes, we showed that it is possible to modulate CD8+ T cell responses to several viral antigens in vitro. We showed that incubation of peripheral blood mononuclear cells with these epitopes triggers proliferation of CD4+CD25+FoxP3+ T cells that suppress killing of target cells loaded with MHC class I antigens in an antigen-specific fashion, through a mechanism that seems to require cell-to-cell contact. Expression of a construct encoding for the AAV capsid structural protein fused to Tregitopes resulted in reduction of CD8+ T cell reactivity against the AAV capsid following immunization with an adenoviral vector expressing capsid. This was accompanied by an increase in frequency of CD4+CD25+FoxP3+ T cells in spleens and lower levels of inflammatory infiltrates in injected tissues. This proof-of-concept study demonstrates modulation of CD8+ T cell reactivity to an antigen using regulatory T cell epitopes is possible.

  1. Vaccination with Altered Peptide Ligands of a Plasmodium berghei Circumsporozoite Protein CD8 T-Cell Epitope: A Model to Generate T Cells Resistant to Immune Interference by Polymorphic Epitopes

    PubMed Central

    Minigo, Gabriela; Flanagan, Katie L.; Slattery, Robyn M.; Plebanski, Magdalena

    2017-01-01

    Many pathogens, including the malaria parasite Plasmodium falciparum, display high levels of polymorphism within T-cell epitope regions of proteins associated with protective immunity. The T-cell epitope variants are often non-cross-reactive. Herein, we show in a murine model, which modifies a protective CD8 T-cell epitope from the circumsporozoite protein (CS) of Plasmodium berghei (SYIPSAEKI), that simultaneous or sequential co-stimulation with two of its putative similarly non-cross-reactive altered peptide ligand (APL) epitopes (SYIPSAEDI or SYIPSAEAI) has radically different effects on immunity. Hence, co-immunization or sequential stimulation in vivo of SYIPSAEKI with its APL antagonist SYIPSAEDI decreases immunity to both epitopes. By contrast, co-immunization with SYIPSAEAI has no apparent initial effect, but it renders the immune response to SYIPSAEKI resistant to being turned off by subsequent immunization with SYIPSAEDI. These results suggest a novel strategy for vaccines that target polymorphic epitopes potentially capable of mutual immune interference in the field, by initiating an immune response by co-immunization with the desired index epitope, together with a carefully selected “potentiator” APL peptide. PMID:28261200

  2. DNA vaccines encoding altered peptide ligands for SSX2 enhance epitope-specific CD8+ T-cell immune responses.

    PubMed

    Smith, Heath A; Rekoske, Brian T; McNeel, Douglas G

    2014-03-26

    Plasmid DNA serves as a simple and easily modifiable form of antigen delivery for vaccines. The USDA approval of DNA vaccines for several non-human diseases underscores the potential of this type of antigen delivery method as a cost-effective approach for the treatment or prevention of human diseases, including cancer. However, while DNA vaccines have demonstrated safety and immunological effect in early phase clinical trials, they have not consistently elicited robust anti-tumor responses. Hence many recent efforts have sought to increase the immunological efficacy of DNA vaccines, and we have specifically evaluated several target antigens encoded by DNA vaccine as treatments for human prostate cancer. In particular, we have focused on SSX2 as one potential target antigen, given its frequent expression in metastatic prostate cancer. We have previously identified two peptides, p41-49 and p103-111, as HLA-A2-restricted SSX2-specific epitopes. In the present study we sought to determine whether the efficacy of a DNA vaccine could be enhanced by an altered peptide ligand (APL) strategy wherein modifications were made to anchor residues of these epitopes to enhance or ablate their binding to HLA-A2. A DNA vaccine encoding APL modified to increase epitope binding elicited robust peptide-specific CD8+ T cells producing Th1 cytokines specific for each epitope. Ablation of one epitope in a DNA vaccine did not enhance immune responses to the other epitope. These results demonstrate that APL encoded by a DNA vaccine can be used to elicit increased numbers of antigen-specific T cells specific for multiple epitopes simultaneously, and suggest this could be a general approach to improve the immunogenicity of DNA vaccines encoding tumor antigens.

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

    PubMed Central

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

    2015-01-01

    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

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

    PubMed

    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.

  5. Different Vaccine Vectors Delivering the Same Antigen Elicit CD8+ T Cell Responses with Distinct Clonotype and Epitope Specificity

    SciTech Connect

    Honda, M.; Robinson, H.; Wang, R.; Kong, W.-P.; Kanekiyo, M.; Akahata, W.; Xu, L.; Matsuo, K.; Natarajan, K.; Asher, T. E.; Price, D. A.; Douek, D. C.; Margulies, D. H.; Nabel, G. J.

    2009-08-15

    Prime-boost immunization with gene-based vectors has been developed to generate more effective vaccines for AIDS, malaria, and tuberculosis. Although these vectors elicit potent T cell responses, the mechanisms by which they stimulate immunity are not well understood. In this study, we show that immunization by a single gene product, HIV-1 envelope, with alternative vector combinations elicits CD8{sup +} cells with different fine specificities and kinetics of mobilization. Vaccine-induced CD8{sup +} T cells recognized overlapping third V region loop peptides. Unexpectedly, two anchor variants bound H-2D{sup d} better than the native sequences, and clones with distinct specificities were elicited by alternative vectors. X-ray crystallography revealed major differences in solvent exposure of MHC-bound peptide epitopes, suggesting that processed HIV-1 envelope gave rise to MHC-I/peptide conformations recognized by distinct CD8{sup +} T cell populations. These findings suggest that different gene-based vectors generate peptides with alternative conformations within MHC-I that elicit distinct T cell responses after vaccination.

  6. Different Vaccine Vectors Delivering the Same Antigen Elicit CD8plus T Cell Responses with Distinct Clonotype and Epitope Specificity

    SciTech Connect

    M Honda; R Wang; W Kong; M Kanekiyo; Q Akahata; L Xu; K Matsuo; K Natarajan; H Robinson; et al.

    2011-12-31

    Prime-boost immunization with gene-based vectors has been developed to generate more effective vaccines for AIDS, malaria, and tuberculosis. Although these vectors elicit potent T cell responses, the mechanisms by which they stimulate immunity are not well understood. In this study, we show that immunization by a single gene product, HIV-1 envelope, with alternative vector combinations elicits CD8{sup +} cells with different fine specificities and kinetics of mobilization. Vaccine-induced CD8{sup +} T cells recognized overlapping third V region loop peptides. Unexpectedly, two anchor variants bound H-2D{sup d} better than the native sequences, and clones with distinct specificities were elicited by alternative vectors. X-ray crystallography revealed major differences in solvent exposure of MHC-bound peptide epitopes, suggesting that processed HIV-1 envelope gave rise to MHC-I/peptide conformations recognized by distinct CD8{sup +} T cell populations. These findings suggest that different gene-based vectors generate peptides with alternative conformations within MHC-I that elicit distinct T cell responses after vaccination.

  7. TCR Affinity Associated with Functional Differences between Dominant and Subdominant SIV Epitope-Specific CD8+ T Cells in Mamu-A*01+ Rhesus Monkeys

    PubMed Central

    Osuna, Christa E.; Gonzalez, Ana Maria; Chang, Hsun-Hsien; Hung, Amy Shi; Ehlinger, Elizabeth; Anasti, Kara; Alam, S. Munir; Letvin, Norman L.

    2014-01-01

    Many of the factors that contribute to CD8+ T cell immunodominance hierarchies during viral infection are known. However, the functional differences that exist between dominant and subdominant epitope-specific CD8+ T cells remain poorly understood. In this study, we characterized the phenotypic and functional differences between dominant and subdominant simian immunodeficiency virus (SIV) epitope-specific CD8+ T cells restricted by the major histocompatibility complex (MHC) class I allele Mamu-A*01 during acute and chronic SIV infection. Whole genome expression analyses during acute infection revealed that dominant SIV epitope-specific CD8+ T cells had a gene expression profile consistent with greater maturity and higher cytotoxic potential than subdominant epitope-specific CD8+ T cells. Flow-cytometric measurements of protein expression and anti-viral functionality during chronic infection confirmed these phenotypic and functional differences. Expression analyses of exhaustion-associated genes indicated that LAG-3 and CTLA-4 were more highly expressed in the dominant epitope-specific cells during acute SIV infection. Interestingly, only LAG-3 expression remained high during chronic infection in dominant epitope-specific cells. We also explored the binding interaction between peptide:MHC (pMHC) complexes and their cognate TCRs to determine their role in the establishment of immunodominance hierarchies. We found that epitope dominance was associated with higher TCR:pMHC affinity. These studies demonstrate that significant functional differences exist between dominant and subdominant epitope-specific CD8+ T cells within MHC-restricted immunodominance hierarchies and suggest that TCR:pMHC affinity may play an important role in determining the frequency and functionality of these cell populations. These findings advance our understanding of the regulation of T cell immunodominance and will aid HIV vaccine design. PMID:24743648

  8. TCR affinity associated with functional differences between dominant and subdominant SIV epitope-specific CD8+ T cells in Mamu-A*01+ rhesus monkeys.

    PubMed

    Osuna, Christa E; Gonzalez, Ana Maria; Chang, Hsun-Hsien; Hung, Amy Shi; Ehlinger, Elizabeth; Anasti, Kara; Alam, S Munir; Letvin, Norman L

    2014-04-01

    Many of the factors that contribute to CD8+ T cell immunodominance hierarchies during viral infection are known. However, the functional differences that exist between dominant and subdominant epitope-specific CD8+ T cells remain poorly understood. In this study, we characterized the phenotypic and functional differences between dominant and subdominant simian immunodeficiency virus (SIV) epitope-specific CD8+ T cells restricted by the major histocompatibility complex (MHC) class I allele Mamu-A*01 during acute and chronic SIV infection. Whole genome expression analyses during acute infection revealed that dominant SIV epitope-specific CD8+ T cells had a gene expression profile consistent with greater maturity and higher cytotoxic potential than subdominant epitope-specific CD8+ T cells. Flow-cytometric measurements of protein expression and anti-viral functionality during chronic infection confirmed these phenotypic and functional differences. Expression analyses of exhaustion-associated genes indicated that LAG-3 and CTLA-4 were more highly expressed in the dominant epitope-specific cells during acute SIV infection. Interestingly, only LAG-3 expression remained high during chronic infection in dominant epitope-specific cells. We also explored the binding interaction between peptide:MHC (pMHC) complexes and their cognate TCRs to determine their role in the establishment of immunodominance hierarchies. We found that epitope dominance was associated with higher TCR:pMHC affinity. These studies demonstrate that significant functional differences exist between dominant and subdominant epitope-specific CD8+ T cells within MHC-restricted immunodominance hierarchies and suggest that TCR:pMHC affinity may play an important role in determining the frequency and functionality of these cell populations. These findings advance our understanding of the regulation of T cell immunodominance and will aid HIV vaccine design.

  9. Positive Selection in CD8+ T-Cell Epitopes of Influenza Virus Nucleoprotein Revealed by a Comparative Analysis of Human and Swine Viral Lineages

    PubMed Central

    Machkovech, Heather M.; Bedford, Trevor; Suchard, Marc A.

    2015-01-01

    ABSTRACT Numerous experimental studies have demonstrated that CD8+ T cells contribute to immunity against influenza by limiting viral replication. It is therefore surprising that rigorous statistical tests have failed to find evidence of positive selection in the epitopes targeted by CD8+ T cells. Here we use a novel computational approach to test for selection in CD8+ T-cell epitopes. We define all epitopes in the nucleoprotein (NP) and matrix protein (M1) with experimentally identified human CD8+ T-cell responses and then compare the evolution of these epitopes in parallel lineages of human and swine influenza viruses that have been diverging since roughly 1918. We find a significant enrichment of substitutions that alter human CD8+ T-cell epitopes in NP of human versus swine influenza virus, consistent with the idea that these epitopes are under positive selection. Furthermore, we show that epitope-altering substitutions in human influenza virus NP are enriched on the trunk versus the branches of the phylogenetic tree, indicating that viruses that acquire these mutations have a selective advantage. However, even in human influenza virus NP, sites in T-cell epitopes evolve more slowly than do nonepitope sites, presumably because these epitopes are under stronger inherent functional constraint. Overall, our work demonstrates that there is clear selection from CD8+ T cells in human influenza virus NP and illustrates how comparative analyses of viral lineages from different hosts can identify positive selection that is otherwise obscured by strong functional constraint. IMPORTANCE There is a strong interest in correlates of anti-influenza immunity that are protective against diverse virus strains. CD8+ T cells provide such broad immunity, since they target conserved viral proteins. An important question is whether T-cell immunity is sufficiently strong to drive influenza virus evolution. Although many studies have shown that T cells limit viral replication in animal

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

    PubMed Central

    2010-01-01

    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 monitor HLA-A2

  11. Phenotypic and Functional Characterization of Herpes Simplex Virus Glycoprotein B Epitope-Specific Effector and Memory CD8+ T Cells from Symptomatic and Asymptomatic Individuals with Ocular Herpes

    PubMed Central

    Khan, Arif A.; Srivastava, Ruchi; Spencer, Doran; Garg, Sumit; Fremgen, Daniel; Vahed, Hawa; Lopes, Patricia P.; Pham, Thanh T.; Hewett, Charlie; Kuang, Jasmine; Ong, Nicolas; Huang, Lei; Scarfone, Vanessa M.; Nesburn, Anthony B.

    2015-01-01

    ABSTRACT Herpes simplex virus 1 (HSV-1) glycoprotein B (gB)-specific CD8+ T cells protect mice from herpes infection and disease. However, whether and which HSV-1 gB-specific CD8+ T cells play a key role in the “natural” protection seen in HSV-1-seropositive healthy asymptomatic (ASYMP) individuals (who have never had clinical herpes disease) remain to be determined. In this study, we have dissected the phenotypes and the functions of HSV-1 gB-specific CD8+ T cells from HLA-A*02:01 positive, HSV-1 seropositive ASYMP and symptomatic (SYMP) individuals (with a history of numerous episodes of recurrent ocular herpes disease). We found the following. (i) Healthy ASYMP individuals maintained a significantly higher proportion of differentiated HSV-1 gB-specific effector memory CD8+ T cells (TEM cells) (CD45RAlow CCR7low CD44high CD62Llow). In contrast, SYMP patients had frequent less-differentiated central memory CD8+ T cells (TCM cells) (CD45RAlow CCR7high CD44low CD62Lhigh). (ii) ASYMP individuals had significantly higher proportions of multifunctional effector CD8+ T cells which responded mainly to gB342–350 and gB561–569 “ASYMP” epitopes, and simultaneously produced IFN-γ, CD107a/b, granzyme B, and perforin. In contrast, effector CD8+ T cells from SYMP individuals were mostly monofunctional and were directed mainly against nonoverlapping gB17–25 and gB183–191 “SYMP” epitopes. (iii) Immunization of an HLA-A*02:01 transgenic mouse model of ocular herpes with “ASYMP” CD8+ TEM cell epitopes, but not with “SYMP” CD8+ TCM cell epitopes, induced a strong CD8+ T cell-dependent protective immunity against ocular herpes infection and disease. Our findings provide insights into the role of HSV-specific CD8+ TEM cells in protection against herpes and should be considered in the development of an effective vaccine. IMPORTANCE A significantly higher proportion of differentiated and multifunctional HSV-1 gB-specific effector memory CD8+ T cells (TEM

  12. HLA-A*0201 restricted CD8+ T-lymphocyte responses to malaria: identification of new Plasmodium falciparum epitopes by IFN-gamma ELISPOT.

    PubMed

    González, J M; Peter, K; Esposito, F; Nebié, I; Tiercy, J M; Bonelo, A; Arévalo-Herrera, M; Valmori, D; Romero, P; Herrera, S; Corradin, G; López, J A

    2000-10-01

    The role of antigen specific CD8+ T-lymphocytes in mediating protection against sporozoite-induced malaria has been well established in murine models. In humans, indirect evidence has accumulated suggesting a similar protective role for antigen-specific CD8+ T-lymphocytes. Nevertheless, the low frequency of circulating specific cells together with the lack of sensitive methods to quantify them has hampered the direct assessment of their function. Using a combination of short-term cell culture and IFN-gamma ELISPOT, we studied CD8+ T-lymphocyte responses to a panel of HLA-A*0201 binding peptides. In addition to confirming the response to already described epitopes, we also identified five new CD8+ T-lymphocyte epitopes. These epitopes are presented in pre-erythrocytic stages gene products of Plasmodium falciparum 7G8 strain and correspond to the following protein segments: circumsporozoite (CS) 64-72, 104-113, 299-308 and 403-411; liver stage antigen (LSA-1) repeat region; sporozoite surface protein 2 or thrombospondin related anonymous protein (SSP2/TRAP) 78-88 and 504-513. Four of these peptides are conserved amongst all published sequences of P. falciparum strains. We conclude that the modified IFN-gamma ELISPOT assay is a sensitive technique to monitor antigen-specific CD8+ T-lymphocyte responses in human malaria which may help in the improvement and assessment of the efficacy of malaria subunit vaccines.

  13. Epitope Mapping with Random Phage Display Library

    PubMed Central

    Midoro-Horiuti, Terumi; Goldblum, Randall M.

    2017-01-01

    Random phage display library is used to map conformational as well as linear epitopes. These libraries are available in varying lengths and with circularization. We provide here a protocol conveying our experience using a commercially available peptide phage display library, which in our hands provides good results. PMID:24515483

  14. HLA-B*27 subtype specificity determines targeting and viral evolution of a hepatitis C virus-specific CD8+ T-cell epitope

    PubMed Central

    Nitschke, Katja; Barriga, Alejandro; Schmidt, Julia; Timm, Jörg; Viazov, Sergei; Kuntzen, Thomas; Kim, Arthur Y.; Lauer, Georg M.; Allen, Todd M.; Gaudieri, Silvana; Rauch, Andri; Lange, Christian M.; Sarrazin, Christoph; Eiermann, Thomas; Sidney, John; Sette, Alessandro; Thimme, Robert; López, Daniel; Neumann-Haefelin, Christoph

    2013-01-01

    Background & Aims HLA-B*27 is associated with spontaneous HCV genotype 1 clearance. HLA-B*27-restricted CD8+ T-cells target three NS5B epitopes. Two of these epitopes are dominantly targeted in the majority of HLA-B*27+ patients. In chronic infection, viral escape occurs consistently in these two epitopes. The third epitope (NS5B2820) was dominantly targeted in an acutely infected patient. This was in contrast, however, to the lack of recognition and viral escape in the large majority of HLA-B*27+ patients. Here, we set out to determine the host factors contributing to selective targeting of this epitope. Methods Four-digit HLA class I typing and viral sequence analyses were performed in 78 HLA-B*27+ patients with chronic HCV genotype 1 infection. CD8+ T-cell analyses were performed in a subset of patients. In addition, HLA/peptide affinity was compared for HLA-B*27:02 and 05. Results The NS5B2820 epitope is only restricted by the HLA-B*27 subtype HLA-B*27:02 (that is frequent in Mediterranean populations), but not by the prototype HLA-B*27 subtype B*27:05. Indeed, the epitope is very dominant in HLA-B*27:02+ patients and is associated with viral escape mutations at the anchor position for HLA-binding in 12 out of 13 HLA-B*27:02+ chronically infected patients. Conclusions The NS5B2820 epitope is immunodominant in the context of HLA-B*27:02, but is not restricted by other HLA-B*27 subtypes. This finding suggests an important role of HLA subtypes in the restriction of HCV-specific CD8+ responses. With minor HLA subtypes covering up to 39% of specific populations, these findings may have important implications for the selection of epitopes for global vaccines. PMID:23978718

  15. Defining the mechanism(s) of protection by cytolytic CD8 T cells against a cryptic epitope derived from a retroviral alternative reading frame

    PubMed Central

    Rutkowski, Melanie R.; Ho, On; Green, William R.

    2009-01-01

    The biological significance of protective CD8 T-cell-mediated responses against non-traditional alternative reading frame epitopes remains relatively unknown. Cytolytic CD8 T cells (CTL) specific for a non-traditional cryptic MHC class I epitope, SYNTGRFPPL, are critically involved in the protection of mice during infection with the LP-BM5 murine retrovirus. The goal of this study was to determine the functional properties of the protective SYNTGRFPPL-specific CTL during LP-BM5 infection of susceptible BALB/c CD8−/− mice. Direct infection experiments and adoptive transfer of CD8 T cells derived from perforin (pfp)−/−, IFNγ−/−, FasL−/− and, as a positive control, wild-type BALB/c mice, were utilized to assess the effector mechanisms responsible for protection. Our results indicate that SYNTGRFPPL-specific effector CTL preferentially utilize perforin-mediated cytolysis to provide protection against LP-BM5-induced pathogenesis, whereas CTL production of IFNγ is not required. Our results also suggest a minimal contribution of FasL/Fas-mediated lysis during the effector response. Collectively, these results provide insight into effector mechanisms utilized by protective CTL directed against non-traditional cryptic epitopes during disease protection. PMID:19539970

  16. Reconstitution of CD8 T Cells Protective against Cytomegalovirus in a Mouse Model of Hematopoietic Cell Transplantation: Dynamics and Inessentiality of Epitope Immunodominance

    PubMed Central

    Holtappels, Rafaela; Lemmermann, Niels A. W.; Podlech, Jürgen; Ebert, Stefan; Reddehase, Matthias J.

    2016-01-01

    Successful reconstitution of cytomegalovirus (CMV)-specific CD8+ T cells by hematopoietic cell transplantation (HCT) gives a favorable prognosis for the control of CMV reactivation and prevention of CMV disease after hematoablative therapy of hematopoietic malignancies. In the transient immunocompromised state after HCT, pre-emptive cytoimmunotherapy with viral epitope-specific effector or memory CD8+ T cells is a promising option to speed up antiviral control. Despite high-coding capacity of CMVs and a broad CD8+ T-cell response on the population level, which reflects polymorphism in major histocompatibility complex class-I (MHC-I) glycoproteins, the response in terms of quantity of CD8+ T cells in any individual is directed against a limited set of CMV-encoded epitopes selected for presentation by the private repertoire of MHC-I molecules. Such epitopes are known as “immunodominant” epitopes (IDEs). Besides host immunogenetics, genetic variance in CMV strains harbored as latent viruses by an individual HCT recipient can also determine the set of IDEs, which complicates a “personalized immunotherapy.” It is, therefore, an important question if IDE-specific CD8+ T-cell reconstitution after HCT is critical or dispensable for antiviral control. As viruses with targeted mutations of IDEs cannot be experimentally tested in HCT patients, we employed the well-established mouse model of HCT. Notably, control of murine CMV (mCMV) after HCT was comparably efficient for IDE-deletion mutant mCMV-Δ4IDE and the corresponding IDE-expressing revertant virus mCMV-Δ4IDE-rev. Thus, antigenicity-loss mutations in IDEs do not result in loss-of-function of a polyclonal CD8+ T-cell population. Although IDE deletion was not associated with global changes in the response to non-IDE epitopes, the collective of non-IDE-specific CD8+ T-cells infiltrates infected tissue and confines infection within nodular inflammatory foci. We conclude from the model, and predict also for human

  17. Protective Effect of Human Leukocyte Antigen B27 in Hepatitis C Virus Infection Requires the Presence of a Genotype-Specific Immunodominant CD8+ T-Cell Epitope

    PubMed Central

    Kersting, Nadine; Fitzmaurice, Karen; Oniangue-Ndza, Cesar; Kemper, Michael N.; Humphreys, Isla; McKiernan, Susan; Kelleher, Dermot; Lohmann, Volker; Bowness, Paul; Huzly, Daniela; Rosen, Hugo R.; Kim, Arthur Y.; Lauer, Georg M.; Allen, Todd M.; Barnes, Eleanor; Roggendorf, Michael; Blum, Hubert E.; Thimme, Robert

    2015-01-01

    Human leukocyte antigen B27 (HLA-B27) is associated with protection in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection. This protective role is linked to single immunodominant HLA-B27-restricted CD8+ T-cell epitopes in both infections. In order to define the relative contribution of a specific HLA-B27-restricted epitope to the natural course of HCV infection, we compared the biological impact of the highly conserved HCV genotype 1 epitope, for which the protective role has been described, with the corresponding region in genotype 3 that differs in its sequence by three amino acid residues. The genotype 3a peptide was not recognized by CD8+ T cells specific for the genotype 1 peptide. Furthermore, patients with acute or chronic infection with HCV genotype 3a did not mount T-cell responses to this epitope region, and their autologous viral sequences showed no evidence of T-cell pressure. Finally, we found a significantly higher frequency of HLA-B27 positivity in patients with chronic HCV genotype 3a infection compared to genotype 1 infection, indicating that there is no protection by HLA-B27 in HCV genotype 3 infection. Conclusion Our data indicate that the protective effect of HLA-B27 is limited to HCV genotype 1 infection and does not expand to other genotypes such as genotype 3a. This can most likely be explained by intergenotype sequence diversity leading to the loss of the immunodominant HLA-B27 epitope in viral strains other than genotype 1. Our results underline the central role of a single HLA-B27-restricted epitope-specific CD8+ T-cell response in mediating protection in HCV genotype 1 infection. PMID:20034048

  18. Polyfunctional CD8(+) T cells are associated with the vaccination-induced control of a novel recombinant influenza virus expressing an HCV epitope.

    PubMed

    Tan, Amabel C L; Eriksson, Emily M Y; Kedzierska, Katherine; Deliyannis, Georgia; Valkenburg, Sophie A; Zeng, Weiguang; Jackson, David C

    2012-05-01

    In hepatitis C virus (HCV) infection, CD8(+) T cell responses have been shown to be important in viral clearance. Examining the efficacy of CD8(+) T cell vaccines against HCV has been limited by the lack of an HCV infectious model in mice and the differences between MHC restriction in humans and mice. Using HLA-A2 transgenic HHD mice, we demonstrate that intranasally delivered Pam2Cys-based lipopeptides containing HLA-A2-restricted HCV epitopes can induce polyfunctional CD8(+) T cell responses in several organs including the liver. To examine the activity of these responses in an infectious context, we developed a recombinant influenza virus that expresses the NS5B(2594-2602) epitope from non-structural protein 5B of hepatitis C virus (PR8-HCV(NS5B)). We showed that mice inoculated with a lipopeptide containing the NS5B epitope had reduced viral loads following challenge with the PR8-HCV(NS5B) virus. This reduction was associated with the induction of NS5B(2594-2602)-specific IFN-γ and TNF-α co-producing CD8(+) T cells. The T cell receptor usage in the NS5B(2594-2602) response was found to exhibit a Vβ8.1/8.2 bias that was characterized by a narrow repertoire and a common CDR3β motif. This work has identified CD8(+) T cell functions induced by lipopeptides that are associated with viral control and demonstrate the potential of lipopeptide-based vaccines as candidates for treatment of HCV infection.

  19. A genital tract peptide epitope vaccine targeting TLR-2 efficiently induces local and systemic CD8 + T cells and protects against herpes simplex virus type 2 challenge

    PubMed Central

    Dasgupta, G; Nesburn, AB; Wu, M; Zhu, X; Carpenter, D; Wechsler, SL; You, S; BenMohamed, L

    2015-01-01

    The next generation of needle-free mucosal vaccines is being rationally designed according to rules that govern the way in which the epitopes are recognized by and stimulate the genital mucosal immune system. We hypothesized that synthetic peptide epitopes extended with an agonist of Toll-like receptor 2 (TLR-2), that are abundantly expressed by dendritic and epithelial cells of the vaginal mucosa, would lead to induction of protective immunity against genital herpes. To test this hypothesis, we intravaginally (IVAG) immunized wild-type B6, TLR-2 (TLR2 −/−) or myeloid differentiation factor 88 deficient (MyD88 −/−) mice with a herpes simplex virus type 2 (HSV-2) CD8 + T-cell peptide epitope extended by a palmitic acid moiety (a TLR-2 agonist). IVAG delivery of the lipopeptide generated HSV-2-specific memory CD8 + cytotoxic T cells both locally in the genital tract draining lymph nodes and systemically in the spleen. Moreover, lipopeptide-immunized TLR2 −/− and MyD88 −/− mice developed significantly less HSV-specific CD8 + T-cell response, earlier death, faster disease progression, and higher vaginal HSV-2 titers compared to lipopeptide-immunized wild-type B6 mice. IVAG immunization with self-adjuvanting lipid-tailed peptides appears to be a novel mucosal vaccine approach, which has attractive practical and immunological features. PMID:19129756

  20. Control of HIV-1 replication in vitro by vaccine-induced human CD8+ T cells through conserved subdominant Pol epitopes

    PubMed Central

    Ahmed, Tina; Borthwick, Nicola J.; Gilmour, Jill; Hayes, Peter; Dorrell, Lucy; Hanke, Tomáš

    2016-01-01

    Objective The specificity of CD8+ T cells is critical for early control of founder/transmitted and reactivated HIV-1. To tackle HIV-1 variability and escape, we designed vaccine immunogen HIVconsv assembled from 14 highly conserved regions of mainly Gag and Pol proteins. When administered to HIV-1-negative human volunteers in trial HIV-CORE 002, HIVconsv vaccines elicited CD8+ effector T cells which inhibited replication of up to 8 HIV-1 isolates in autologous CD4+ cells. This inhibition correlated with interferon-γ production in response to Gag and Pol peptide pools, but direct evidence of the inhibitory specificity was missing. Here, we aimed to define through recognition of which epitopes these effectors inhibit HIV-1 replication. Design CD8+ T-cells from the 3 broadest HIV-1 inhibitors out of 23 vaccine recipients were expanded in culture by Gag or Pol peptide restimulation and tested in viral inhibition assay (VIA) using HIV-1 clade B and A isolates. Methods Frozen PBMCs were expanded first using peptide pools from Gag or Pol conserved regions and tested on HIV-1-infected cells in VIA or by individual peptides for their effector functions. Single peptide specificities responsible for inhibition of HIV-1 replication were then confirmed by single-peptide expanded effectors tested on HIV-1-infected cells. Results We formally demonstrated that the vaccine-elicited inhibitory human CD8+ T cells recognized conserved epitopes of both Pol and Gag proteins. We defined 7 minimum epitopes, of which 3 were novel, presumably naturally subdominant. The effectors were oligofunctional producing several cytokines and chemokines and killing peptide-pulsed target cells. Conclusions These results implicate the use of functionally conserved regions of Pol in addition to the widely used Gag for T-cell vaccine design. Proportion of volunteers developing these effectors and their frequency in circulating PBMC are separate issues, which can be addressed, if needed, by more efficient

  1. Cutting edge: DNAX accessory molecule 1-deficient CD8+ T cells display immunological synapse defects that impair antitumor immunity.

    PubMed

    Ramsbottom, Kelly M; Hawkins, Edwin D; Shimoni, Raz; McGrath, Mairi; Chan, Christopher J; Russell, Sarah M; Smyth, Mark J; Oliaro, Jane

    2014-01-15

    DNAX accessory molecule 1 (DNAM-1) is expressed on all CD8(+) T cells and promotes their activation and effector function. DNAM-1 interacts with LFA-1, a critical molecule for immunological synapse formation between T cells and APCs, and for cytotoxic killing of target cells. Mice that lack DNAM-1 display abnormal T cell responses and antitumor activity; however, the mechanism involved is unclear. In this article, we show that DNAM-1 deficiency results in reduced proliferation of CD8(+) T cells after Ag presentation and impaired cytotoxic activity. We also demonstrate that DNAM-1-deficient T cells show reduced conjugations with tumor cells and decreased recruitment of both LFA-1 and lipid rafts to the immunological synapse, which correlates with reduced tumor cell killing in vitro. This synapse defect may explain why DNAM-1-deficient mice cannot clear tumors in vivo, and highlights the importance of DNAM-1 and the immunological synapse in T cell-mediated antitumor immunity.

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

    PubMed

    Karlsson, Ingrid; Kløverpris, Henrik; Jensen, Kristoffer Jarlov; Stryhn, Anette; Buus, Søren; Karlsson, Annika; Vinner, Lasse; Goulder, Philip; Fomsgaard, Anders

    2012-11-01

    The high HIV-1 prevalence, up to 4.6% in Guinea-Bissau, West Africa, makes it a relevant location for testing of therapeutic vaccines. With the aim of performing a clinical study in Guinea-Bissau, after first testing the vaccine for safety in Denmark, Europe, we here describe the design 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-specific, HLA-restricted T cell specificities using peptide-MHC class I tetramer labeling of CD8(+) T cells from HIV-1-infected individuals. The selected vaccine epitopes are infrequently targeted in HIV-1-infected individuals from both locations. Moreover, we HLA-typed HIV-1-infected individuals and demonstrated that the selected vaccine epitopes, when targeted, are restricted to the five most common HLA supertypes at both locations. Thus, the HLA supertype-directed approach achieved HLA coverage of 95% and 100% of the examined cohorts in Guinea-Bissau and Denmark, respectively. In conclusion, the selected vaccine epitopes match the host populations and HIV-1 strains of these two distant geographic regions, justifying clinical testing in both locations.

  3. Vaccine Targeting of Subdominant CD8+ T Cell Epitopes Increases the Breadth of the T Cell Response upon Viral Challenge, but May Impair Immediate Virus Control.

    PubMed

    Steffensen, Maria A; Pedersen, Louise H; Jahn, Marie L; Nielsen, Karen N; Christensen, Jan P; Thomsen, Allan R

    2016-03-15

    As a result of the difficulties in making efficient vaccines against genetically unstable viruses such as HIV, it has been suggested that future vaccines should preferentially target subdominant epitopes, the idea being that this should allow a greater breadth of the induced T cell response and, hence, a greater efficiency in controlling escape variants. However, to our knowledge the evidence supporting this concept is limited at best. To improve upon this, we used the murine lymphocytic choriomeningitis virus model and adenoviral vectors to compare a vaccine expressing unmodified Ag to a vaccine expressing the same Ag without its immunodominant epitope. We found that removal of the dominant epitope allowed the induction of CD8(+) T cell responses targeting at least two otherwise subdominant epitopes. Importantly, the overall magnitude of the induced T cell responses was similar, allowing us to directly compare the efficiency of these vaccines. Doing this, we observed that mice vaccinated with the vaccine expressing unmodified Ag more efficiently controlled an acute viral challenge. In the course of a more chronic viral infection, mice vaccinated using the vaccine targeting subdominant epitopes caught up with the conventionally vaccinated mice, and analysis of the breadth of the CD8(+) T cell response revealed that this was notably greater in the former mice. However, under the conditions of our studies, we never saw any functional advantage of this. This may represent a limitation of our model, but clearly our findings underscore the importance of carefully weighing the pros and cons of changes in epitope targeting before any implementation.

  4. Sterile Immunity to Malaria after DNA Prime/Adenovirus Boost Immunization Is Associated with Effector Memory CD8+T Cells Targeting AMA1 Class I Epitopes

    PubMed Central

    Sedegah, Martha; Hollingdale, Michael R.; Farooq, Fouzia; Ganeshan, Harini; Belmonte, Maria; Kim, Yohan; Peters, Bjoern; Sette, Alessandro; Huang, Jun; McGrath, Shannon; Abot, Esteban; Limbach, Keith; Shi, Meng; Soisson, Lorraine; Diggs, Carter; Chuang, Ilin; Tamminga, Cindy; Epstein, Judith E.; Villasante, Eileen; Richie, Thomas L.

    2014-01-01

    Background Fifteen volunteers were immunized with three doses of plasmid DNA encoding P. falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1) and boosted with human adenovirus-5 (Ad) expressing the same antigens (DNA/Ad). Four volunteers (27%) demonstrated sterile immunity to controlled human malaria infection and, overall, protection was statistically significantly associated with ELISpot and CD8+ T cell IFN-γ activities to AMA1 but not CSP. DNA priming was required for protection, as 18 additional subjects immunized with Ad alone (AdCA) did not develop sterile protection. Methodology/Principal Findings We sought to identify correlates of protection, recognizing that DNA-priming may induce different responses than AdCA alone. Among protected volunteers, two and three had higher ELISpot and CD8+ T cell IFN-γ responses to CSP and AMA1, respectively, than non-protected volunteers. Unexpectedly, non-protected volunteers in the AdCA trial showed ELISpot and CD8+ T cell IFN-γ responses to AMA1 equal to or higher than the protected volunteers. T cell functionality assessed by intracellular cytokine staining for IFN-γ, TNF-α and IL-2 likewise did not distinguish protected from non-protected volunteers across both trials. However, three of the four protected volunteers showed higher effector to central memory CD8+ T cell ratios to AMA1, and one of these to CSP, than non-protected volunteers for both antigens. These responses were focused on discrete regions of CSP and AMA1. Class I epitopes restricted by A*03 or B*58 supertypes within these regions of AMA1 strongly recalled responses in three of four protected volunteers. We hypothesize that vaccine-induced effector memory CD8+ T cells recognizing a single class I epitope can confer sterile immunity to P. falciparum in humans. Conclusions/Significance We suggest that better understanding of which epitopes within malaria antigens can confer sterile immunity and design of vaccine approaches

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

    PubMed

    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.

  6. CD8+ T cell recognition of epitopes within the capsid of adeno-associated virus 8-based gene transfer vectors depends on vectors' genome.

    PubMed

    Wu, Te-Lang; Li, Hua; Faust, Susan M; Chi, Emily; Zhou, Shangzhen; Wright, Fraser; High, Katherine A; Ertl, Hildegund C J

    2014-01-01

    Self-complementary adeno-associated viral (AAV) vectors expressing human factor IX (hF.IX) have achieved transient or sustained correction of hemophilia B in human volunteers. High doses of AAV2 or AAV8 vectors delivered to the liver caused in several patients an increase in transaminases accompanied by a rise in AAV capsid-specific T cells and a decrease in circulating hF.IX levels suggesting immune-mediated destruction of vector-transduced cells. Kinetics of these adverse events differed in patients receiving AAV2 or AAV8 vectors causing rise in transaminases at 3 versus 8 weeks after vector injection, respectively. To test if CD8+ T cells to AAV8 vectors, which are similar to AAV2 vectors are fully-gutted vectors and thereby fail to encode structural viral proteins, could cause damage at this late time point, we tested in a series of mouse studies how long major histocompatibility (MHC) class I epitopes within AAV8 capsid can be presented to CD8+ T cells. Our results clearly show that depending on the vectors' genome, CD8+ T cells can detect such epitopes on AAV8's capsid for up to 6 months indicating that the capsid of AAV8 degrades slowly in mice.

  7. Gene Expression Driven by a Strong Viral Promoter in MVA Increases Vaccination Efficiency by Enhancing Antibody Responses and Unmasking CD8⁺ T Cell Epitopes.

    PubMed

    Becker, Pablo D; Nörder, Miriam; Weissmann, Sebastian; Ljapoci, Ronny; Erfle, Volker; Drexler, Ingo; Guzmán, Carlos A

    2014-07-22

    Viral vectors are promising tools for vaccination strategies and immunotherapies. However, CD8⁺ T cell responses against pathogen-derived epitopes are usually limited to dominant epitopes and antibody responses to recombinant encoded antigens (Ags) are mostly weak. We have previously demonstrated that the timing of viral Ag expression in infected professional Ag-presenting cells strongly shapes the epitope immunodominance hierarchy. T cells recognizing determinants derived from late viral proteins have a clear disadvantage to proliferate during secondary responses. In this work we evaluate the effect of overexpressing the recombinant Ag using the modified vaccinia virus early/late promoter H5 (mPH5). Although the Ag-expression from the natural promoter 7.5 (P7.5) and the mPH5 seemed similar, detailed analysis showed that mPH5 not only induces higher expression levels than P7.5 during early phase of infection, but also Ag turnover is enhanced. The strong overexpression during the early phase leads to broader CD8 T cell responses, while preserving the priming efficiency of stable Ags. Moreover, the increase in Ag-secretion favors the induction of strong antibody responses. Our findings provide the rationale to develop new strategies for fine-tuning the responses elicited by recombinant modified vaccinia virus Ankara by using selected promoters to improve the performance of this viral vector.

  8. Sequence conservation, HLA-E-Restricted peptide, and best-defined CTL/CD8+ epitopes in gag P24 (capsid) of HIV-1 subtype B

    NASA Astrophysics Data System (ADS)

    Prasetyo, Afiono Agung; Dharmawan, Ruben; Sari, Yulia; Sariyatun, Ratna

    2017-02-01

    Human immunodeficiency virus type 1 (HIV-1) remains a cause of global health problem. Continuous studies of HIV-1 genetic and immunological profiles are important to find strategies against the virus. This study aimed to conduct analysis of sequence conservation, HLA-E-restricted peptide, and best-defined CTL/CD8+ epitopes in p24 (capsid) of HIV-1 subtype B worldwide. The p24-coding sequences from 3,557 HIV subtype B isolates were aligned using MUSCLE and analysed. Some highly conserved regions (sequence conservation ≥95%) were observed. Two considerably long series of sequences with conservation of 100% was observed at base 349-356 and 550-557 of p24 (HXB2 numbering). The consensus from all aligned isolates was precisely the same as consensus B in the Los Alamos HIV Database. The HLA-E-restricted peptide in amino acid (aa) 14-22 of HIV-1 p24 (AISPRTLNA) was found in 55.9% (1,987/3,557) of HIV-1 subtype B worldwide. Forty-four best-defined CTL/CD8+ epitopes were observed, in which VKNWMTETL epitope (aa 181-189 of p24) restricted by B*4801 was the most frequent, as found in 94.9% of isolates. The results of this study would contribute information about HIV-1 subtype B and benefits for further works willing to develop diagnostic and therapeutic strategies against the virus.

  9. Human Memory Cytotoxic T-Lymphocyte (CTL) Responses to Hantaan Virus Infection: Identification of Virus-Specific and Cross-Reactive CD8+ CTL Epitopes on Nucleocapsid Protein

    PubMed Central

    Van Epps, Heather L.; Schmaljohn, Connie S.; Ennis, Francis A.

    1999-01-01

    Hantaan virus, the prototypic member of the Hantavirus genus, causes hemorrhagic fever with renal syndrome in humans. We examined the human memory T-lymphocyte responses of three donors who had previous laboratory-acquired infections with Hantaan virus. We demonstrated virus-specific responses in bulk cultures of peripheral blood mononuclear cells (PBMC) from all donors. Bulk T-cell responses were directed against either Hantaan virus nucleocapsid (N) or G1 protein, and these responses varied between donors. We established both CD4+ and CD8+ N-specific cell lines from two donors and CD4+ G1-specific cell lines from a third donor. All CD8+ cytotoxic T-lymphocyte (CTL) lines recognized one of two epitopes on the nucleocapsid protein: one epitope spanning amino acids 12 to 20 and the other spanning amino acids 421 to 429. The CTL lines specific for amino acids 12 to 20 were restricted by HLA B51, and those specific for amino acids 421 to 429 were restricted by HLA A1. The N-specific CTL lines isolated from these two donors included both Hantaan virus-specific CTLs and hantavirus cross-reactive CTLs. Responses to both epitopes are detectable in short-term bulk cultures of PBMC from one donor, and precursor frequency analysis confirms that CTLs specific for these epitopes are present at relatively high precursor frequencies in the peripheral T-cell pool. These data suggest that infection with Hantaan virus results in the generation of CTL to limited epitopes on the nucleocapsid protein and that infection also results in the generation of cross-reactive T-cell responses to distantly related hantaviruses which cause the distinct hantavirus pulmonary syndrome. This is the first demonstration of human T-lymphocyte responses to Hantaan virus. PMID:10364276

  10. A Novel CD8-Independent High-Avidity Cytotoxic T-Lymphocyte Response Directed against an Epitope in the Phosphoprotein of the Paramyxovirus Simian Virus 5

    PubMed Central

    Gray, Peter M.; Parks, Griffith D.; Alexander-Miller, Martha A.

    2001-01-01

    Adoptive transfer studies have shown that cytotoxic T lymphocytes (CTL) of high avidity, capable of recognizing low levels of peptide-MHC I molecules, are more efficient at reducing viral titers than are low-avidity CTL, thus establishing CTL avidity as a critical parameter for the ability of a CTL to clear virus in vivo. It has been well documented that CTL of high avidity are relatively CD8 independent, whereas low-avidity CTL require CD8 engagement in order to become activated. In this study we have analyzed the antiviral CTL response elicited following infection with the paramyxovirus simian virus 5 (SV5). We have identified the immunodominant and subdominant CTL responses and subsequently assessed the avidity of these responses by their CD8 dependence. This is the first study in which the relationship between immunodominance and CTL avidity has been investigated. The immunodominant response was directed against an epitope present in the viral M protein, and subdominant responses were directed against epitopes present in the P, F, and HN proteins. Similarly to other CTL responses we have analyzed, the immunodominant response and the subdominant F and HN responses were comprised of both high- and low-avidity CTL. However, the subdominant response directed against the epitope present in the P protein is novel, as it is exclusively high avidity. This high-avidity response is independent of both the route of infection and expression by recombinant SV5. A further understanding of the inherent properties of P that elicit only high-avidity CTL may allow for the design of more efficacious vaccine vectors that preferentially elicit high-avidity CTL in vivo. PMID:11581375

  11. A Chimera Containing CD4+ and CD8+ T-Cell Epitopes of the Leishmania donovani Nucleoside Hydrolase (NH36) Optimizes Cross-Protection against Leishmania amazonesis Infection.

    PubMed

    Alves-Silva, Marcus Vinícius; Nico, Dirlei; Morrot, Alexandre; Palatnik, Marcos; Palatnik-de-Sousa, Clarisa B

    2017-01-01

    The Leishmania donovani nucleoside hydrolase (NH36) and NH A34480 of Leishmania amazonensis share 93% of sequence identity. In mice, the NH36 induced protection against visceral leishmaniasis is mediated by a CD4+ T cell response against its C-terminal domain (F3). Besides this CD4+ Th1 response, prevention and cure of L. amazonensis infection require also additional CD8+ and regulatory T-cell responses to the NH36 N-terminal (F1 domain). We investigated if mice vaccination with F1 and F3 domains cloned in tandem, in a recombinant chimera, with saponin, optimizes the vaccine efficacy against L. amazonensis infection above the levels promoted by the two admixed domains or by each domain independently. The chimera induced the highest IgA, IgG, and IgG2a anti-NH36 antibody, IDR, IFN-γ, and IL-10 responses, while TNF-α was more secreted by mice vaccinated with F3 or all F3-contaning vaccines. Additionally, the chimera and the F1 vaccine also induced the highest proportions of CD4+ and CD8+ T cells secreting IL-2, TNF-α, or IFN-γ alone, TNF-α in combination with IL-2 or IFN-γ, and of CD4+ multifunctional cells secreting IL-2, TNF-α, and IFN-γ. Correlating with the immunological results, the strongest reductions of skin lesions sizes were determined by the admixed domains (80%) and by the chimera (84%), which also promoted the most pronounced and significant reduction of the parasite load (99.8%). Thus, the epitope presentation in a recombinant chimera optimizes immunogenicity and efficacy above the levels induced by the independent or admixed F1 and F3 domains. The multiparameter analysis disclosed that the Th1-CD4+ T helper response induced by the chimera is mainly directed against its FRYPRPKHCHTQVA epitope. Additionally, the YPPEFKTKL epitope of F1 induced the second most important CD4+ T cell response, and, followed by the DVAGIVGVPVAAGCT, FMLQILDFYTKVYE, and ELLAITTVVGNQ sequences, also the most potent CD8+ T cell responses and IL-10 secretion. Remarkably

  12. A Chimera Containing CD4+ and CD8+ T-Cell Epitopes of the Leishmania donovani Nucleoside Hydrolase (NH36) Optimizes Cross-Protection against Leishmania amazonesis Infection

    PubMed Central

    Alves-Silva, Marcus Vinícius; Nico, Dirlei; Morrot, Alexandre; Palatnik, Marcos; Palatnik-de-Sousa, Clarisa B.

    2017-01-01

    The Leishmania donovani nucleoside hydrolase (NH36) and NH A34480 of Leishmania amazonensis share 93% of sequence identity. In mice, the NH36 induced protection against visceral leishmaniasis is mediated by a CD4+ T cell response against its C-terminal domain (F3). Besides this CD4+ Th1 response, prevention and cure of L. amazonensis infection require also additional CD8+ and regulatory T-cell responses to the NH36 N-terminal (F1 domain). We investigated if mice vaccination with F1 and F3 domains cloned in tandem, in a recombinant chimera, with saponin, optimizes the vaccine efficacy against L. amazonensis infection above the levels promoted by the two admixed domains or by each domain independently. The chimera induced the highest IgA, IgG, and IgG2a anti-NH36 antibody, IDR, IFN-γ, and IL-10 responses, while TNF-α was more secreted by mice vaccinated with F3 or all F3-contaning vaccines. Additionally, the chimera and the F1 vaccine also induced the highest proportions of CD4+ and CD8+ T cells secreting IL-2, TNF-α, or IFN-γ alone, TNF-α in combination with IL-2 or IFN-γ, and of CD4+ multifunctional cells secreting IL-2, TNF-α, and IFN-γ. Correlating with the immunological results, the strongest reductions of skin lesions sizes were determined by the admixed domains (80%) and by the chimera (84%), which also promoted the most pronounced and significant reduction of the parasite load (99.8%). Thus, the epitope presentation in a recombinant chimera optimizes immunogenicity and efficacy above the levels induced by the independent or admixed F1 and F3 domains. The multiparameter analysis disclosed that the Th1-CD4+ T helper response induced by the chimera is mainly directed against its FRYPRPKHCHTQVA epitope. Additionally, the YPPEFKTKL epitope of F1 induced the second most important CD4+ T cell response, and, followed by the DVAGIVGVPVAAGCT, FMLQILDFYTKVYE, and ELLAITTVVGNQ sequences, also the most potent CD8+ T cell responses and IL-10 secretion. Remarkably

  13. Identification of CD8+ cytotoxic T lymphocyte epitopes from porcine reproductive and respiratory syndrome virus matrix protein in BALB/c mice

    PubMed Central

    2011-01-01

    Twenty-seven nanopeptides derived from the matrix (M) protein of porcine reproductive and respiratory syndrome virus (PRRSV) were screened for their ability to elicit a recall interferon-γ (IFN-γ) response from the splenocytes of BALB/c mice following DNA vaccination and a booster vaccination with recombinant vaccinia virus rWR-PRRSV-M. We identified two peptides (amino acid residues K93FITSRCRL and F57GYMTFVHF) as CD8+ cytotoxic T lymphocyte (CTL) epitopes. These peptides elicited significant numbers of IFN-γ secreting cells, compared with other M nonapeptides and one irrelevant nonapeptide. Bioinformatics analysis showed that the former is an H-2Kd-restricted CTL epitope, and the latter is an H-2Dd-restricted CTL epitope. Multiple amino acid sequence alignment among different PRRSV M sequences submitted to GenBank indicated that these two CTL epitopes are strongly conserved, and they should therefore be considered for further research on the mechanisms of cellular immune responses to PRRSV. PMID:21619712

  14. Selection Pressure in CD8+ T-cell Epitopes in the pol Gene of HIV-1 Infected Individuals in Colombia. A Bioinformatic Approach

    PubMed Central

    Acevedo-Sáenz, Liliana; Ochoa, Rodrigo; Rugeles, Maria Teresa; Olaya-García, Patricia; Velilla-Hernández, Paula Andrea; Diaz, Francisco J.

    2015-01-01

    One of the main characteristics of the human immunodeficiency virus is its genetic variability and rapid adaptation to changing environmental conditions. This variability, resulting from the lack of proofreading activity of the viral reverse transcriptase, generates mutations that could be fixed either by random genetic drift or by positive selection. Among the forces driving positive selection are antiretroviral therapy and CD8+ T-cells, the most important immune mechanism involved in viral control. Here, we describe mutations induced by these selective forces acting on the pol gene of HIV in a group of infected individuals. We used Maximum Likelihood analyses of the ratio of non-synonymous to synonymous mutations per site (dN/dS) to study the extent of positive selection in the protease and the reverse transcriptase, using 614 viral sequences from Colombian patients. We also performed computational approaches, docking and algorithmic analyses, to assess whether the positively selected mutations affected binding to the HLA molecules. We found 19 positively-selected codons in drug resistance-associated sites and 22 located within CD8+ T-cell epitopes. A high percentage of mutations in these epitopes has not been previously reported. According to the docking analyses only one of those mutations affected HLA binding. However, algorithmic methods predicted a decrease in the affinity for the HLA molecule in seven mutated peptides. The bioinformatics strategies described here are useful to identify putative positively selected mutations associated with immune escape but should be complemented with an experimental approach to define the impact of these mutations on the functional profile of the CD8+ T-cells. PMID:25803098

  15. Selection pressure in CD8⁺ T-cell epitopes in the pol gene of HIV-1 infected individuals in Colombia. A bioinformatic approach.

    PubMed

    Acevedo-Sáenz, Liliana; Ochoa, Rodrigo; Rugeles, Maria Teresa; Olaya-García, Patricia; Velilla-Hernández, Paula Andrea; Diaz, Francisco J

    2015-03-20

    One of the main characteristics of the human immunodeficiency virus is its genetic variability and rapid adaptation to changing environmental conditions. This variability, resulting from the lack of proofreading activity of the viral reverse transcriptase, generates mutations that could be fixed either by random genetic drift or by positive selection. Among the forces driving positive selection are antiretroviral therapy and CD8+ T-cells, the most important immune mechanism involved in viral control. Here, we describe mutations induced by these selective forces acting on the pol gene of HIV in a group of infected individuals. We used Maximum Likelihood analyses of the ratio of non-synonymous to synonymous mutations per site (dN/dS) to study the extent of positive selection in the protease and the reverse transcriptase, using 614 viral sequences from Colombian patients. We also performed computational approaches, docking and algorithmic analyses, to assess whether the positively selected mutations affected binding to the HLA molecules. We found 19 positively-selected codons in drug resistance-associated sites and 22 located within CD8+ T-cell epitopes. A high percentage of mutations in these epitopes has not been previously reported. According to the docking analyses only one of those mutations affected HLA binding. However, algorithmic methods predicted a decrease in the affinity for the HLA molecule in seven mutated peptides. The bioinformatics strategies described here are useful to identify putative positively selected mutations associated with immune escape but should be complemented with an experimental approach to define the impact of these mutations on the functional profile of the CD8+ T-cells.

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

    PubMed

    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.

  17. Analysis of the T Cell Response to Zika Virus and Identification of a Novel CD8+ T Cell Epitope in Immunocompetent Mice

    PubMed Central

    Pardy, Ryan D.; Rajah, Maaran M.; Taylor, Nathan G.

    2017-01-01

    Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family. Although ZIKV infection is typically mild and self-limiting in healthy adults, infection has been associated with neurological symptoms such as Guillain-Barré syndrome, and a causal link has been established between fetal microcephaly and ZIKV infection during pregnancy. These risks, and the magnitude of the ongoing ZIKV pandemic, have created an urgent need for the development of animal models to study the immune response to ZIKV infection. Previous animal models have primarily focused on pathogenesis in immunocompromised mice. In this study, we provide a model of ZIKV infection in wild-type immunocompetent C57BL/6 mice, and have provided an analysis of the immune response to infection. We evaluated the activation of several innate immune cell types, and studied the kinetics, phenotype, and functionality of T cell responses to ZIKV infection. Our results demonstrate that ZIKV infection is mild in wild-type immunocompetent C57BL/6 mice, resulting in minimal morbidity. Our data establish that at the peak of the adaptive response, antigen-experienced CD4+ T cells polarize to a Th1 phenotype, and antigen-experienced CD8+ T cells exhibit an activated effector phenotype, producing both effector cytokines and cytolytic molecules. Furthermore, we have identified a novel ZIKV CD8+ T cell epitope in the envelope protein that is recognized by the majority of responding cells. Our model provides an important reference point that will help dissect the impact of polymorphisms in the circulating ZIKV strains on the immune response and ZIKV pathogenesis. In addition, the identification of a ZIKV epitope will allow for the design of tetramers to study epitope-specific T cell responses, and will have important implications for the design and development of ZIKV vaccine strategies. PMID:28231312

  18. Analysis of the T Cell Response to Zika Virus and Identification of a Novel CD8+ T Cell Epitope in Immunocompetent Mice.

    PubMed

    Pardy, Ryan D; Rajah, Maaran M; Condotta, Stephanie A; Taylor, Nathan G; Sagan, Selena M; Richer, Martin J

    2017-02-01

    Zika virus (ZIKV) is an emerging arbovirus of the Flaviviridae family. Although ZIKV infection is typically mild and self-limiting in healthy adults, infection has been associated with neurological symptoms such as Guillain-Barré syndrome, and a causal link has been established between fetal microcephaly and ZIKV infection during pregnancy. These risks, and the magnitude of the ongoing ZIKV pandemic, have created an urgent need for the development of animal models to study the immune response to ZIKV infection. Previous animal models have primarily focused on pathogenesis in immunocompromised mice. In this study, we provide a model of ZIKV infection in wild-type immunocompetent C57BL/6 mice, and have provided an analysis of the immune response to infection. We evaluated the activation of several innate immune cell types, and studied the kinetics, phenotype, and functionality of T cell responses to ZIKV infection. Our results demonstrate that ZIKV infection is mild in wild-type immunocompetent C57BL/6 mice, resulting in minimal morbidity. Our data establish that at the peak of the adaptive response, antigen-experienced CD4+ T cells polarize to a Th1 phenotype, and antigen-experienced CD8+ T cells exhibit an activated effector phenotype, producing both effector cytokines and cytolytic molecules. Furthermore, we have identified a novel ZIKV CD8+ T cell epitope in the envelope protein that is recognized by the majority of responding cells. Our model provides an important reference point that will help dissect the impact of polymorphisms in the circulating ZIKV strains on the immune response and ZIKV pathogenesis. In addition, the identification of a ZIKV epitope will allow for the design of tetramers to study epitope-specific T cell responses, and will have important implications for the design and development of ZIKV vaccine strategies.

  19. Flavivirus-cross-reactive, HLA-DR15-restricted epitope on NS3 recognized by human CD4+ CD8- cytotoxic T lymphocyte clones.

    PubMed

    Kurane, I; Okamoto, Y; Dai, L C; Zeng, L L; Brinton, M A; Ennis, F A

    1995-09-01

    The role of flavivirus-cross-reactive T lymphocytes in recovery from and pathogenesis of flavivirus infections is not known. In the present paper, we have defined a flavivirus-cross-reactive epitope recognized by two CD4+ CD8- cytotoxic T lymphocyte (CTL) clones, JK4 and JK43. The T cell clones were established from the peripheral blood T lymphocytes of a dengue-4-immune donor, using a limiting-dilution method with dengue-4 antigen. These two T cell clones were cross-reactive for dengue virus types 1, 2, 3 and 4, yellow fever virus and West Nile virus, and recognized NS3 protein. The smallest synthetic peptide recognized by these T cell clones was an identical 9 amino acid peptide which contains amino acids 146 to 154 (VIGLYGNGV) of dengue-4 NS3. HLA-DR15 was the restriction allele for recognition of this epitope by JK4 and JK43. JK4 and JK43 both used T cell receptor V alpha 8, but JK4 used V beta 8 and JK43 used V beta 2. This result indicates that this epitope is recognized by two flavivirus-cross-reactive CD4+ T cell clones which originated from different T cells in vivo.

  20. Cross-Protective Immunity to Leishmania amazonensis is Mediated by CD4+ and CD8+ Epitopes of Leishmania donovani Nucleoside Hydrolase Terminal Domains

    PubMed Central

    Nico, Dirlei; Gomes, Daniele Crespo; Alves-Silva, Marcus Vinícius; Freitas, Elisangela Oliveira; Morrot, Alexandre; Bahia, Diana; Palatnik, Marcos; Rodrigues, Mauricio M.; Palatnik-de-Sousa, Clarisa B.

    2014-01-01

    The nucleoside hydrolase (NH) of Leishmania donovani (NH36) is a phylogenetic marker of high homology among Leishmania parasites. In mice and dog vaccination, NH36 induces a CD4+ T cell-driven protective response against Leishmania chagasi infection directed against its C-terminal domain (F3). The C-terminal and N-terminal domain vaccines also decreased the footpad lesion caused by Leishmania amazonensis. We studied the basis of the crossed immune response using recombinant generated peptides covering the whole NH36 sequence and saponin for mice prophylaxis against L. amazonensis. The F1 (amino acids 1–103) and F3 peptide (amino acids 199–314) vaccines enhanced the IgG and IgG2a anti-NH36 antibodies to similar levels. The F3 vaccine induced the strongest DTH response, the highest proportions of NH36-specific CD4+ and CD8+ T cells after challenge and the highest expression of IFN-γ and TNF-α. The F1 vaccine, on the other hand, induced a weaker but significant DTH response and a mild enhancement of IFN-γ and TNF-α levels. The in vivo depletion with anti-CD4 or CD8 monoclonal antibodies disclosed that cross-protection against L. amazonensis infection was mediated by a CD4+ T cell response directed against the C-terminal domain (75% of reduction of the size of footpad lesion) followed by a CD8+ T cell response against the N-terminal domain of NH36 (57% of reduction of footpad lesions). Both vaccines were capable of inducing long-term cross-immunity. The amino acid sequence of NH36 showed 93% identity to the sequence of the NH A34480 of L. amazonensis, which also showed the presence of completely conserved predicted epitopes for CD4+ and CD8+ T cells in F1 domain, and of CD4+ epitopes differing by a single amino acid, in F1 and F3 domains. The identification of the C-terminal and N-terminal domains as the targets of the immune response to NH36 in the model of L. amazonensis infection represents a basis for the rationale development of a bivalent vaccine against

  1. In Silico Analysis of Six Known Leishmania major Antigens and In Vitro Evaluation of Specific Epitopes Eliciting HLA-A2 Restricted CD8 T Cell Response

    PubMed Central

    Seyed, Negar; Zahedifard, Farnaz; Safaiyan, Shima; Gholami, Elham; Doustdari, Fatemeh; Azadmanesh, Kayhan; Mirzaei, Maryam; Saeedi Eslami, Nasir; Khadem Sadegh, Akbar; Eslami far, Ali; Sharifi, Iraj; Rafati, Sima

    2011-01-01

    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 mapping L. major epitopes for

  2. Immunization with a peptide containing MHC class I and II epitopes derived from the tumor antigen SIM2 induces an effective CD4 and CD8 T-cell response.

    PubMed

    Kissick, Haydn T; Sanda, Martin G; Dunn, Laura K; Arredouani, Mohamed S

    2014-01-01

    Here, we sought to determine whether peptide vaccines designed harbor both class I as well as class II restricted antigenic motifs could concurrently induce CD4 and CD8 T cell activation against autologous tumor antigens. Based on our prior genome-wide interrogation of human prostate cancer tissues to identify genes over-expressed in cancer and absent in the periphery, we targeted SIM2 as a prototype autologous tumor antigen for these studies. Using humanized transgenic mice we found that the 9aa HLA-A*0201 epitope, SIM2(237-245), was effective at inducing an antigen specific response against SIM2-expressing prostate cancer cell line, PC3. Immunization with a multi-epitope peptide harboring both MHC-I and MHC-II restricted epitopes induced an IFN-γ response in CD8 T cells to the HLA-A*0201-restricted SIM2(237-245) epitope, and an IL-2 response by CD4 T cells to the SIM2(240-254) epitope. This peptide was also effective at inducing CD8+ T-cells that responded specifically to SIM2-expressing tumor cells. Collectively, the data presented in this study suggest that a single peptide containing multiple SIM2 epitopes can be used to induce both a CD4 and CD8 T cell response, providing a peptide-based vaccine formulation for potential use in immunotherapy of various cancers.

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

    PubMed Central

    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

    2011-01-01

    Summary HLA-A*0201-restricted virus-specific CD8+ cytotoxic T lymphocytes (CTLs) do not appear to control HIV effectively in vivo. To enhance the immunogenicity of a highly conserved subdominant epitope, TV9 (TLNAWVKVV, p24 Gag19–27), mimotopes were designed by screening a large combinatorial nonapeptide library with TV9-specific CTLs 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 CTLs showed that TV9p6 consistently activated crossreactive and equally functional CTLs as measured by cytotoxicity, cytokine production and suppression of HIV replication in vitro. Comparison of TCRB gene usage between CTLs 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 crossreactive clonotypes that are less readily recruited from the naïve T cell pool by the corresponding wildtype 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

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

    PubMed

    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.

  5. The Human CD8+ T Cell Responses Induced by a Live Attenuated Tetravalent Dengue Vaccine Are Directed against Highly Conserved Epitopes

    PubMed Central

    Angelo, Michael A.; Bangs, Derek J.; Sidney, John; Paul, Sinu; Peters, Bjoern; de Silva, Aruna D.; Lindow, Janet C.; Diehl, Sean A.; Whitehead, Stephen; Durbin, Anna; Kirkpatrick, Beth; Sette, Alessandro

    2014-01-01

    ABSTRACT The incidence of infection with any of the four dengue virus serotypes (DENV1 to -4) has increased dramatically in the last few decades, and the lack of a treatment or vaccine has contributed to significant morbidity and mortality worldwide. A recent comprehensive analysis of the human T cell response against wild-type DENV suggested an human lymphocyte antigen (HLA)-linked protective role for CD8+ T cells. We have collected one-unit blood donations from study participants receiving the monovalent or tetravalent live attenuated DENV vaccine (DLAV), developed by the U.S. National Institutes of Health. Peripheral blood mononuclear cells from these donors were screened in gamma interferon enzyme-linked immunosorbent spot assays with pools of predicted, HLA-matched, class I binding peptides covering the entire DENV proteome. Here, we characterize for the first time CD8+ T cell responses after live attenuated dengue vaccination and show that CD8+ T cell responses in vaccinees were readily detectable and comparable to natural dengue infection. Interestingly, whereas broad responses to structural and nonstructural (NS) proteins were observed after monovalent vaccination, T cell responses following tetravalent vaccination were, dramatically, focused toward the highly conserved NS proteins. Epitopes were highly conserved in a vast variety of field isolates and able to elicit multifunctional T cell responses. Detailed knowledge of the T cell response will contribute to the identification of robust correlates of protection in natural immunity and following vaccination against DENV. IMPORTANCE The development of effective vaccination strategies against dengue virus (DENV) infection and clinically significant disease is a task of high global public health value and significance, while also being a challenge of significant complexity. A recent efficacy trial of the most advanced dengue vaccine candidate, demonstrated only partial protection against all four DENV

  6. 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.

    PubMed

    Shi, Jiandong; Sun, Jing; Wu, Meini; Hu, Ningzhu; Li, Jianfan; Li, Yanhan; Wang, Haixuan; Hu, Yunzhang

    2015-01-01

    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.

  7. 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.

    PubMed

    Dommaraju, Kalpana; Kijak, Gustavo; Carlson, Jonathan M; Larsen, Brendan B; Tovanabutra, Sodsai; Geraghty, Dan E; Deng, Wenjie; Maust, Brandon S; Edlefsen, Paul T; Sanders-Buell, Eric; Ratto-Kim, Silvia; deSouza, Mark S; Rerks-Ngarm, Supachai; Nitayaphan, Sorachai; Pitisuttihum, Punnee; Kaewkungwal, Jaranit; O'Connell, Robert J; Robb, Merlin L; Michael, Nelson L; Mullins, James I; Kim, Jerome H; Rolland, Morgane

    2014-01-01

    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.

  8. 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

    PubMed Central

    Dommaraju, Kalpana; Kijak, Gustavo; Carlson, Jonathan M.; Larsen, Brendan B.; Tovanabutra, Sodsai; Geraghty, Dan E.; Deng, Wenjie; Maust, Brandon S.; Edlefsen, Paul T.; Sanders-Buell, Eric; Ratto-Kim, Silvia; deSouza, Mark S.; Rerks-Ngarm, Supachai; Nitayaphan, Sorachai; Pitisuttihum, Punnee; Kaewkungwal, Jaranit; O'Connell, Robert J.; Robb, Merlin L.; Michael, Nelson L.; Mullins, James I.; Kim, Jerome H.; Rolland, Morgane

    2014-01-01

    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. PMID:25350851

  9. A recombinant chimeric protein composed of human and mice-specific CD4(+) and CD8(+) T-cell epitopes protects against visceral leishmaniasis.

    PubMed

    Martins, V T; Duarte, M C; Lage, D P; Costa, L E; Carvalho, A M R S; Mendes, T A O; Roatt, B M; Menezes-Souza, D; Soto, M; Coelho, E A F

    2017-01-01

    In this study, a recombinant chimeric protein (RCP), which was composed of specific CD4(+) and CD8(+) T-cell epitopes to murine and human haplotypes, was evaluated as an immunogen against Leishmania infantum infection in a murine model. BALB/c mice received saline were immunized with saponin or with RCP with or without an adjuvant. The results showed that RCP/saponin-vaccinated mice presented significantly higher levels of antileishmanial IFN-γ, IL-12 and GM-CSF before and after challenge, which were associated with the reduction of IL-4 and IL-10 mediated responses. These animals showed significant reductions in the parasite burden in all evaluated organs, when both limiting dilution and quantitative real-time PCR techniques were used. In addition, the protected animals presented higher levels of parasite-specific nitrite, as well as the presence of anti-Leishmania IgG2a isotype antibodies. In conclusion, the RCP/saponin vaccine could be considered as a prophylactic alternative to prevent against VL.

  10. CCR2+ Inflammatory Dendritic Cells and Translocation of Antigen by Type III Secretion Are Required for the Exceptionally Large CD8+ T Cell Response to the Protective YopE69-77 Epitope during Yersinia Infection

    PubMed Central

    Zhang, Yue; Tam, Jason W.; Mena, Patricio; van der Velden, Adrianus W. M.; Bliska, James B.

    2015-01-01

    During Yersinia pseudotuberculosis infection of C57BL/6 mice, an exceptionally large CD8+ T cell response to a protective epitope in the type III secretion system effector YopE is produced. At the peak of the response, up to 50% of splenic CD8+ T cells recognize the epitope YopE69-77. The features of the interaction between pathogen and host that result in this large CD8+ T cell response are unknown. Here, we used Y. pseudotuberculosis strains defective for production, secretion and/or translocation of YopE to infect wild-type or mutant mice deficient in specific dendritic cells (DCs). Bacterial colonization of organs and translocation of YopE into spleen cells was measured, and flow cytometry and tetramer staining were used to characterize the cellular immune response. We show that the splenic YopE69-77-specific CD8+ T cells generated during the large response are polyclonal and are produced by a “translocation-dependent” pathway that requires injection of YopE into host cell cytosol. Additionally, a smaller YopE69-77-specific CD8+ T cell response (~10% of the large expansion) can be generated in a “translocation-independent” pathway in which CD8α+ DCs cross present secreted YopE. CCR2-expressing inflammatory DCs were required for the large YopE69-77-specific CD8+ T cell expansion because this response was significantly reduced in Ccr2-/- mice, YopE was translocated into inflammatory DCs in vivo, inflammatory DCs purified from infected spleens activated YopE69-77-specific CD8+ T cells ex vivo and promoted the expansion of YopE69-77-specific CD8+ T cells in infected Ccr2-/- mice after adoptive transfer. A requirement for inflammatory DCs in producing a protective CD8+ T cell response to a bacterial antigen has not previously been demonstrated. Therefore, the production of YopE69-77-specific CD8+ T cells by inflammatory DCs that are injected with YopE during Y. pseudotuberculosis infection represents a novel mechanism for generating a massive and protective

  11. Beyond HLA-A*0201: new HLA-transgenic nonobese diabetic mouse models of type 1 diabetes identify the insulin C-peptide as a rich source of CD8+ T cell epitopes.

    PubMed

    Antal, Zoltan; Baker, Jason C; Smith, Carla; Jarchum, Irene; Babad, Jeffrey; Mukherjee, Gayatri; Yang, Yang; Sidney, John; Sette, Alessandro; Santamaria, Pere; DiLorenzo, Teresa P

    2012-06-01

    Type 1 diabetes is an autoimmune disease characterized by T cell responses to β cell Ags, including insulin. Investigations employing the NOD mouse model of the disease have revealed an essential role for β cell-specific CD8(+) T cells in the pathogenic process. As CD8(+) T cells specific for β cell Ags are also present in patients, these reactivities have the potential to serve as therapeutic targets or markers for autoimmune activity. NOD mice transgenic for human class I MHC molecules have previously been employed to identify T cell epitopes having important relevance to the human disease. However, most studies have focused exclusively on HLA-A*0201. To broaden the reach of epitope-based monitoring and therapeutic strategies, we have looked beyond this allele and developed NOD mice expressing human β(2)-microglobulin and HLA-A*1101 or HLA-B*0702, which are representative members of the A3 and B7 HLA supertypes, respectively. We have used islet-infiltrating T cells spontaneously arising in these strains to identify β cell peptides recognized in the context of the transgenic HLA molecules. This work has identified the insulin C-peptide as an abundant source of CD8(+) T cell epitopes. Responses to these epitopes should be of considerable utility for immune monitoring, as they cannot reflect an immune reaction to exogenously administered insulin, which lacks the C-peptide. Because the peptides bound by one supertype member were found to bind certain other members also, the epitopes identified in this study have the potential to result in therapeutic and monitoring tools applicable to large numbers of patients and at-risk individuals.

  12. A Herpes Simplex Virus Type 1 Human Asymptomatic CD8+ T-Cell Epitopes-Based Vaccine Protects Against Ocular Herpes in a “Humanized” HLA Transgenic Rabbit Model

    PubMed Central

    Srivastava, Ruchi; Khan, Arif A.; Huang, Jiawei; Nesburn, Anthony B.; Wechsler, Steven L.; BenMohamed, Lbachir

    2015-01-01

    Purpose. A clinical vaccine that protects from ocular herpes simplex virus type 1 (HSV-1) infection and disease still is lacking. In the present study, preclinical vaccine trials of nine asymptomatic (ASYMP) peptides, selected from HSV-1 glycoproteins B (gB), and tegument proteins VP11/12 and VP13/14, were performed in the “humanized” HLA–transgenic rabbit (HLA-Tg rabbit) model of ocular herpes. We recently reported that these peptides are highly recognized by CD8+ T cells from “naturally” protected HSV-1–seropositive healthy ASYMP individuals (who have never had clinical herpes disease). Methods. Mixtures of three ASYMP CD8+ T-cell peptides derived from either HSV-1 gB, VP11/12, or VP13/14 were delivered subcutaneously to different groups of HLA-Tg rabbits (n = 10) in incomplete Freund's adjuvant, twice at 15-day intervals. The frequency and function of HSV-1 epitope-specific CD8+ T cells induced by these peptides and their protective efficacy, in terms of survival, virus replication in the eye, and ocular herpetic disease were assessed after an ocular challenge with HSV-1 (strain McKrae). Results. All mixtures elicited strong and polyfunctional IFN-γ– and TNF-α–producing CD107+CD8+ cytotoxic T cells, associated with a significant reduction in death, ocular herpes infection, and disease (P < 0.015). Conclusions. The results of this preclinical trial support the screening strategy used to select the HSV-1 ASYMP CD8+ T-cell epitopes, emphasize their valuable immunogenic and protective efficacy against ocular herpes, and provide a prototype vaccine formulation that may be highly efficacious for preventing ocular herpes in humans. PMID:26098469

  13. Eliciting Epitope-Specific CD8+ T Cell Response by Immunization with Microbial Protein Antigens Formulated with α-Galactosylceramide: Theory, Practice, and Protocols.

    PubMed

    Gilchuk, Pavlo; Knight, Frances C; Wilson, John T; Joyce, Sebastian

    2017-01-01

    CD8+ cytotoxic T lymphocytes confer protection against infectious diseases caused by viruses, bacteria, and parasites. Hence, significant efforts have been invested into devising ways to generate CD8+ T cell-targeted vaccines. Generation of microbe-free protein subunit vaccines requires a thorough knowledge of protective target antigens. Such antigens are proteolytically processed peptides presented by MHC class I molecules. To induce a robust antigen-specific CD8+ T cell response through vaccination, it is essential to formulate the antigen with an effective adjuvant. Here, we describe a versatile method for generating high-frequency antigen-specific CD8+ T cells through immunization of mice using the invariant natural killer T cell agonist α-galactosylceramide as the adjuvant.

  14. Signal peptides and trans-membrane regions are broadly immunogenic and have high CD8+ T cell epitope densities: Implications for vaccine development.

    PubMed

    Kovjazin, Riva; Volovitz, Ilan; Daon, Yair; Vider-Shalit, Tal; Azran, Roy; Tsaban, Lea; Carmon, Lior; Louzoun, Yoram

    2011-04-01

    Cell mediated immune response has a major role in controlling the elimination of infectious agents. The rational design of sub-unit peptide vaccines against intracellular pathogens or cancer requires the use of antigenic sequence/s that can induce highly potent, long lasting and antigen-specific responses in the majority of the population. A promising peptide selection strategy is the detection of multi-epitope peptide sequences with an ability to bind multiple MHC alleles. While past research sought the best epitopes based on their specific antigenicity, we ask whether specific defined domains have high epitope densities. Signal peptides and trans-membrane domains were found to have exceptionally high epitope densities. The improved MHC binding of these domains relies on their hydrophobic nature and, in signal peptides, also on their specific sequence. The high epitope density of SP was computed using in-silico methods and corroborated by the high percentage of identified SP epitope in the IEDB (immune epitope database). The enhanced immunogenicity of SP was then experimentally confirmed using a panel of nine peptides derived from Mycobacterium tuberculosis (MTb) proteins used in human PBMC proliferation assays and T cell lines functional assays. Our results show the exceptionally high antigen specific response rates and population coverage to SP sequences compared with non-SP peptide antigens derived from the same proteins. The results suggest a novel scheme for the rational design of T cell vaccines using a domain based rather than an epitope based approach.

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

    PubMed Central

    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

  16. Upregulation of interleukin 7 receptor alpha and programmed death 1 marks an epitope-specific CD8+ T-cell response that disappears following primary Epstein-Barr virus infection.

    PubMed

    Sauce, Delphine; Larsen, Martin; Abbott, Rachel J M; Hislop, Andrew D; Leese, Alison M; Khan, Naeem; Papagno, Laura; Freeman, Gordon J; Rickinson, Alan B

    2009-09-01

    In immunocompetent individuals, the stability of the herpesvirus-host balance limits opportunities to study the disappearance of a virus-specific CD8(+) T-cell response. However, we noticed that in HLA-A 0201-positive infectious mononucleosis (IM) patients undergoing primary Epstein-Barr virus (EBV) infection, the initial CD8 response targets three EBV lytic antigen-derived epitopes, YVLDHLIVV (YVL), GLCTLVAML (GLC), and TLDYKPLSV (TLD), but only the YVL and GLC reactivities persist long-term; the TLD response disappears within 10 to 27 months. While present, TLD-specific cells remained largely indistinguishable from YVL and GLC reactivities in many phenotypic and functional respects but showed unique temporal changes in two markers of T-cell fate, interleukin 7 receptor alpha (IL-7Ralpha; CD127) and programmed death 1 (PD-1). Thus, following the antigen-driven downregulation of IL-7Ralpha seen on all populations in acute IM, in every case, the TLD-specific population recovered expression unusually quickly post-IM. As well, in four of six patients studied, TLD-specific cells showed very strong PD-1 upregulation in the last blood sample obtained before the cells' disappearance. Our data suggest that the disappearance of this individual epitope reactivity from an otherwise stable EBV-specific response (i) reflects a selective loss of cognate antigen restimulation (rather than of IL-7-dependent signals) and (ii) is immediately preceded, and perhaps mediated, by PD-1 upregulation to unprecedented levels.

  17. Toward the development of multi-epitope p53 cancer vaccines: an in vitro assessment of CD8(+) T cell responses to HLA class I-restricted wild-type sequence p53 peptides.

    PubMed

    Sakakura, Koichi; Chikamatsu, Kazuaki; Furuya, Nobuhiko; Appella, Ettore; Whiteside, Theresa L; Deleo, Albert B

    2007-10-01

    Wild-type sequence (wt) p53 peptides are attractive candidates for broadly applicable cancer vaccines. Six HLA-A2 or HLA-A24-restricted wt p53 peptides were evaluated for their ex vivo immunogenicity and their potential for use in cancer vaccines. Peripheral blood mononuclear cells (PBMC) obtained from HLA-A*0201(+) and/or HLA-A*2402(+) normal donors and subjects with squamous cell carcinoma of the head and neck (SCCHN) were analyzed for p53 peptide-specific reactivity in ELISPOT IFN-gamma assays. CD8(+) T cells in 7/10 normal donors (HD) and 11/23 subjects with SCCHN responded to at least one of the wt p53 peptides. CD8(+) T cell precursors responsive to wt p53 epitopes were detected in the circulation of most subjects with early disease, and an elevated blood Tc(1)/Tc(2) ratio distinguished wt p53 peptide responders from non-responders. The identification of multiple wt p53 peptides able to induce cytolytic T lymphocytes in most subjects with cancer promotes the development of multi-epitope p53 vaccines.

  18. Naive CD8⁺ T-cell precursors display structured TCR repertoires and composite antigen-driven selection dynamics.

    PubMed

    Neller, Michelle A; Ladell, Kristin; McLaren, James E; Matthews, Katherine K; Gostick, Emma; Pentier, Johanne M; Dolton, Garry; Schauenburg, Andrea J A; Koning, Dan; Fontaine Costa, Ana Isabel C A; Watkins, Thomas S; Venturi, Vanessa; Smith, Corey; Khanna, Rajiv; Miners, Kelly; Clement, Mathew; Wooldridge, Linda; Cole, David K; van Baarle, Debbie; Sewell, Andrew K; Burrows, Scott R; Price, David A; Miles, John J

    2015-08-01

    Basic parameters of the naive antigen (Ag)-specific T-cell repertoire in humans remain poorly defined. Systematic characterization of this 'ground state' immunity in comparison with memory will allow a better understanding of clonal selection during immune challenge. Here, we used high-definition cell isolation from umbilical cord blood samples to establish the baseline frequency, phenotype and T-cell antigen receptor (TCR) repertoire of CD8(+) T-cell precursor populations specific for a range of viral and self-derived Ags. Across the board, these precursor populations were phenotypically naive and occurred with hierarchical frequencies clustered by Ag specificity. The corresponding patterns of TCR architecture were highly ordered and displayed partial overlap with adult memory, indicating biased structuring of the T-cell repertoire during Ag-driven selection. Collectively, these results provide new insights into the complex nature and dynamics of the naive T-cell compartment.

  19. Characterization of cross-reactive CD8+ T-cell recognition of HLA-A2-restricted HIV-Gag (SLYNTVATL) and HCV-NS5b (ALYDVVSKL) epitopes in individuals infected with human immunodeficiency and hepatitis C viruses.

    PubMed

    Vali, Bahareh; Tohn, Robert; Cohen, Michael J; Sakhdari, Ali; Sheth, Prameet M; Yue, Feng Yun; Wong, David; Kovacs, Colin; Kaul, Rupert; Ostrowski, Mario A

    2011-01-01

    The immunologic mechanisms underlying the faster progression of hepatitis C virus (HCV) disease in the presence of human immunodeficiency virus (HIV) coinfection are not clearly understood. T-cell cross-reactivity between HCV and influenza virus-specific epitopes has been associated with rapid progression of HCV disease (S. Urbani, B. Amadei, P. Fisicaro, M. Pilli, G. Missale, A. Bertoletti, and C. Ferrari, J. Exp. Med. 201:675-680, 2005). We asked whether T-cell cross-reactivity between HCV and HIV could exist during HCV/HIV coinfection and affect pathogenesis. Our search for amino acid sequence homology between the HCV and HIV proteomes revealed two similar HLA-A2-restricted epitopes, HIV-Gag (SLYNTVATL [HIV-SL9]) and HCV-NS5b (ALYDVVSKL [HCV-AL9]). We found that 4 out of 20 HLA-A2-positive (HLA-A2(+)) HIV-infected individuals had CD8(+) T cells that recognized both the HIV-SL9 and HCV-AL9 epitopes. However, the AL9 epitope was generally shown to be a weak agonist. Although HCV-monoinfected individuals in our study did not show AL9-specific responses, we found that about half of HCV/HIV-coinfected individuals had dual responses to both epitopes. High dual T-cell recognition among coinfected subjects was usually due to separate T-cell populations targeting each epitope, as determined by pentamer staining. The one individual demonstrating cross-reactive T cells to both epitopes showed the most advanced degree of liver disease. In coinfected individuals, we observed a positive correlation between the magnitudes of T-cell responses to both the SL9 and the AL9 epitopes, which was also positively associated with the clinical parameter of liver damage. Thus, we find that HIV infection induces T cells that can cross-react to heterologous viruses or prime for T cells that are closely related in sequence. However, the induction of cross-reactive T cells may not be associated with control of disease caused by the heterologous virus. This demonstrates that degeneracy of HIV

  20. Lymphocryptovirus Infection of Nonhuman Primate B Cells Converts Destructive into Productive Processing of the Pathogenic CD8 T Cell Epitope in Myelin Oligodendrocyte Glycoprotein

    PubMed Central

    Jagessar, S. Anwar; Holtman, Inge R.; Hofman, Sam; Morandi, Elena; Heijmans, Nicole; Laman, Jon D.; Gran, Bruno; Faber, Bart W.; van Kasteren, Sander I.; Eggen, Bart J. L.

    2016-01-01

    EBV is the major infectious environmental risk factor for multiple sclerosis (MS), but the underlying mechanisms remain obscure. Patient studies do not allow manipulation in vivo. We used the experimental autoimmune encephalomyelitis (EAE) models in the common marmoset and rhesus monkey to model the association of EBV and MS. We report that B cells infected with EBV-related lymphocryptovirus (LCV) are requisite APCs for MHC-E–restricted autoaggressive effector memory CTLs specific for the immunodominant epitope 40-48 of myelin oligodendrocyte glycoprotein (MOG). These T cells drive the EAE pathogenesis to irreversible neurologic deficit. The aim of this study was to determine why LCV infection is important for this pathogenic role of B cells. Transcriptome comparison of LCV-infected B cells and CD20+ spleen cells from rhesus monkeys shows increased expression of genes encoding elements of the Ag cross-presentation machinery (i.e., of proteasome maturation protein and immunoproteasome subunits) and enhanced expression of MHC-E and of costimulatory molecules (CD70 and CD80, but not CD86). It was also shown that altered expression of endolysosomal proteases (cathepsins) mitigates the fast endolysosomal degradation of the MOG40–48 core epitope. Finally, LCV infection also induced expression of LC3-II+ cytosolic structures resembling autophagosomes, which seem to form an intracellular compartment where the MOG40–48 epitope is protected against proteolytic degradation by the endolysosomal serine protease cathepsin G. In conclusion, LCV infection induces a variety of changes in B cells that underlies the conversion of destructive processing of the immunodominant MOG40–48 epitope into productive processing and cross-presentation to strongly autoaggressive CTLs. PMID:27412414

  1. Efficient epitope mapping by bacteriophage {lambda} surface display

    SciTech Connect

    Kuwabara, I.; Maruyama, H.; Zuberi, R.I.

    1997-01-01

    A bacteriophage {lambda} surface expression system, {lambda}foo, was used for epitope mapping of human galectin-3. We constructed random epitope and peptide libraries and compared their efficiencies in the mapping. The galectin-3 cDNA was randomly digested by DNase I to make random epitope libraries. The libraries were screened by affinity selection using a microtiter plate coated with monoclonal antibodies. Direct DNA sequencing of the selected clones defined two distinct epitope sites consisting of nine and 11 amino-acid residues. Affinity selection of random peptide libraries recovered a number of sequences that were similar to each other but distinct from the galectin-3 sequence. These results demonstrate that a single affinity selection of epitope libraries with antibodies is able to define an epitope determinant as small as nine residues long and is more efficient in epitope mapping than random peptide libraries. 25 refs., 4 figs., 1 tab.

  2. Exposure to Melan-A/MART-126-35 tumor epitope specific CD8(+)T cells reveals immune escape by affecting the ubiquitin-proteasome system (UPS).

    PubMed

    Ebstein, Frédéric; Keller, Martin; Paschen, Annette; Walden, Peter; Seeger, Michael; Bürger, Elke; Krüger, Elke; Schadendorf, Dirk; Kloetzel, Peter-M; Seifert, Ulrike

    2016-05-04

    Efficient processing of target antigens by the ubiquitin-proteasome-system (UPS) is essential for treatment of cancers by T cell therapies. However, immune escape due to altered expression of IFN-γ-inducible components of the antigen presentation machinery and consequent inefficient processing of HLA-dependent tumor epitopes can be one important reason for failure of such therapies. Here, we show that short-term co-culture of Melan-A/MART-1 tumor antigen-expressing melanoma cells with Melan-A/MART-126-35-specific cytotoxic T lymphocytes (CTL) led to resistance against CTL-induced lysis because of impaired Melan-A/MART-126-35 epitope processing. Interestingly, deregulation of p97/VCP expression, which is an IFN-γ-independent component of the UPS and part of the ER-dependent protein degradation pathway (ERAD), was found to be essentially involved in the observed immune escape. In support, our data demonstrate that re-expression of p97/VCP in Melan-A/MART-126-35 CTL-resistant melanoma cells completely restored immune recognition by Melan-A/MART-126-35 CTL. In conclusion, our experiments show that impaired expression of IFN-γ-independent components of the UPS can exert rapid immune evasion of tumor cells and suggest that tumor antigens processed by distinct UPS degradation pathways should be simultaneously targeted in T cell therapies to restrict the likelihood of immune evasion due to impaired antigen processing.

  3. Exposure to Melan-A/MART-126-35 tumor epitope specific CD8+T cells reveals immune escape by affecting the ubiquitin-proteasome system (UPS)

    PubMed Central

    Ebstein, Frédéric; Keller, Martin; Paschen, Annette; Walden, Peter; Seeger, Michael; Bürger, Elke; Krüger, Elke; Schadendorf, Dirk; Kloetzel, Peter-M.; Seifert, Ulrike

    2016-01-01

    Efficient processing of target antigens by the ubiquitin-proteasome-system (UPS) is essential for treatment of cancers by T cell therapies. However, immune escape due to altered expression of IFN-γ-inducible components of the antigen presentation machinery and consequent inefficient processing of HLA-dependent tumor epitopes can be one important reason for failure of such therapies. Here, we show that short-term co-culture of Melan-A/MART-1 tumor antigen-expressing melanoma cells with Melan-A/MART-126-35-specific cytotoxic T lymphocytes (CTL) led to resistance against CTL-induced lysis because of impaired Melan-A/MART-126-35 epitope processing. Interestingly, deregulation of p97/VCP expression, which is an IFN-γ-independent component of the UPS and part of the ER-dependent protein degradation pathway (ERAD), was found to be essentially involved in the observed immune escape. In support, our data demonstrate that re-expression of p97/VCP in Melan-A/MART-126-35 CTL-resistant melanoma cells completely restored immune recognition by Melan-A/MART-126-35 CTL. In conclusion, our experiments show that impaired expression of IFN-γ-independent components of the UPS can exert rapid immune evasion of tumor cells and suggest that tumor antigens processed by distinct UPS degradation pathways should be simultaneously targeted in T cell therapies to restrict the likelihood of immune evasion due to impaired antigen processing. PMID:27143649

  4. Human Asymptomatic Epitopes Identified from the Herpes Simplex Virus Tegument Protein VP13/14 (UL47) Preferentially Recall Polyfunctional Effector Memory CD44high CD62Llow CD8+ TEM Cells and Protect Humanized HLA-A*02:01 Transgenic Mice against Ocular Herpesvirus Infection.

    PubMed

    Srivastava, Ruchi; Khan, Arif A; Garg, Sumit; Syed, Sabrina A; Furness, Julie N; Vahed, Hawa; Pham, Tiffany; Yu, Howard T; Nesburn, Anthony B; BenMohamed, Lbachir

    2017-01-15

    Herpes simplex virus 1 (HSV-1) infection is widespread among humans. The HSV-1 virion protein 13/14 (VP13/14), also known as UL47, is a tegument antigen targeted by CD8(+) T cells from HSV-seropositive individuals. However, whether VP13/14-specific CD8(+) T cells play a role in the natural protection seen in asymptomatic (ASYMP) individuals (individuals who have never had a clinical herpetic disease) has not been elucidated. Using predictive computer-assisted algorithms, we identified 10 potential HLA-A*02:01-restricted CD8(+) T-cell epitopes from the 693-amino-acid sequence of the VP13/14 protein. Three out of 10 epitopes exhibited a high to moderate affinity of binding to soluble HLA-A*02:01 molecules. The phenotype and function of CD8(+) T cells specific for each epitope were compared in HLA-A*02:01-positive ASYMP individuals and symptomatic (SYMP) individuals (individuals who have frequent clinical herpetic diseases) using determination of a combination of tetramer frequency and the levels of granzyme B, granzyme K, perforin, gamma interferon, tumor necrosis factor alpha, and interleukin-2 production and CD107(a/b) cytotoxic degranulation. High frequencies of multifunctional CD8(+) T cells directed against three epitopes, VP13/14 from amino acids 286 to 294 (VP13/14286-294), VP13/14 from amino acids 504 to 512 (VP13/14504-512), and VP13/14 from amino acids 544 to 552 (VP13/14544-552), were detected in ASYMP individuals, while only low frequencies were detected in SYMP individuals. The three epitopes also predominantly recalled more CD45RA(low) CD44(high) CCR7(low) CD62L(low) CD8(+) effector memory T cells (TEM cells) in ASYMP individuals than SYMP individuals. Moreover, immunization of HLA-A*02:01 transgenic mice with the three CD8(+) TEM-cell epitopes from ASYMP individuals induced robust and polyfunctional HSV-specific CD8(+) TEM cells associated with strong protective immunity against ocular herpesvirus infection and disease. Our findings outline the

  5. 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

    PubMed Central

    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

  6. Characterization of cloned class I MHC-restricted, CD8+ anti-Meth A cytotoxic T-lymphocytes: recognition of an epitope derived from the Meth A gp110 tumor rejection antigen.

    PubMed

    Fassanito, M A; Loftus, D; De Leo, R M; Law, L W; Appella, E; De Leo, A B

    1994-08-15

    Meth A gp110 has been tentatively identified as a tumor rejection antigen. Following isolation of a class I major histocompatibility complex (MHC)-restricted, CD8+ anti-Meth A cytotoxic T-lymphocyte (CTL), we sought to determine whether the determinant recognized by this CTL was: (a) functional in tumor rejection of Meth A sarcoma; and (b) derived from Meth A gp110. Initially, we isolated an anti-Meth A CTL-resistant variant of Meth A sarcoma, Meth A4R, by immunoselection. The results of the subsequent analysis of Meth A4R cells showed the CTL-defined determinant as having a functional role in transplantation rejection of Meth A sarcoma. Walker et al. (Proc. Natl. Acad. Sci. USA, 89: 7915-7918, 1993) showed that the cationic lipid, N-[1-(2,3-dioleoyloxy)propyl]-N,N,N- trimethylammonium-methyl sulfate, mediated delivery of a recombinant glycoprotein into the cytosol of target cells, making it available for processing and presentation by class I MHC molecules. As a result, the cells were sensitized for cytolysis by a class I MHC-restricted CD8+ CTL, which recognized an epitope expressed by the glycoprotein. In a similar manner, we treated the SV40-transformed BALB/c cell line, SVBalb, which is relatively insensitive to cytolysis by the anti-Meth A CTL, with Meth A gp110 and N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl sulfate. The sensitivities of the treated cells and control cell lines to the anti-Meth A CTL were then examined. The results of these experiments permit us to conclude that the determinant recognized by the anti-Meth A CTL line is derived from Meth A gp110.

  7. Intravaginal immunization with HPV vectors induces tissue-resident CD8+ T cell responses

    PubMed Central

    Çuburu, Nicolas; Graham, Barney S.; Buck, Christopher B.; Kines, Rhonda C.; Pang, Yuk-Ying S.; Day, Patricia M.; Lowy, Douglas R.; Schiller, John T.

    2012-01-01

    The induction of persistent intraepithelial CD8+ T cell responses may be key to the development of vaccines against mucosally transmitted pathogens, particularly for sexually transmitted diseases. Here we investigated CD8+ T cell responses in the female mouse cervicovaginal mucosa after intravaginal immunization with human papillomavirus vectors (HPV pseudoviruses) that transiently expressed a model antigen, respiratory syncytial virus (RSV) M/M2, in cervicovaginal keratinocytes. An HPV intravaginal prime/boost with different HPV serotypes induced 10-fold more cervicovaginal antigen-specific CD8+ T cells than priming alone. Antigen-specific T cell numbers decreased only 2-fold after 6 months. Most genital antigen-specific CD8+ T cells were intra- or subepithelial, expressed αE-integrin CD103, produced IFN-γ and TNF-α, and displayed in vivo cytotoxicity. Using a sphingosine-1-phosphate analog (FTY720), we found that the primed CD8+ T cells proliferated in the cervicovaginal mucosa upon HPV intravaginal boost. Intravaginal HPV prime/boost reduced cervicovaginal viral titers 1,000-fold after intravaginal challenge with vaccinia virus expressing the CD8 epitope M2. In contrast, intramuscular prime/boost with an adenovirus type 5 vector induced a higher level of systemic CD8+ T cells but failed to induce intraepithelial CD103+CD8+ T cells or protect against recombinant vaccinia vaginal challenge. Thus, HPV vectors are attractive gene-delivery platforms for inducing durable intraepithelial cervicovaginal CD8+ T cell responses by promoting local proliferation and retention of primed antigen-specific CD8+ T cells. PMID:23143305

  8. Application of phage peptide display technology for the study of food allergen epitopes.

    PubMed

    Chen, Xueni; Dreskin, Stephen C

    2016-12-20

    Phage peptide display technology has been used to identify IgE-binding mimotopes (mimics of natural epitopes) that mimic conformational epitopes. This approach is effective in the characterization of those epitopes that are important for eliciting IgE-mediated allergic responses by food allergens and those that are responsible for cross-reactivity among allergenic food proteins. Application of this technology will increase our understanding of the mechanisms whereby food allergens elicit allergic reactions, will facilitate the discovery of diagnostic reagents and may lead to mimotope-based immunotherapy.

  9. Protective Antibody and CD8+ T-Cell Responses to the Plasmodium falciparum Circumsporozoite Protein Induced by a Nanoparticle Vaccine

    PubMed Central

    Kaba, Stephen A.; McCoy, Margaret E.; Doll, Tais A. P. F.; Brando, Clara; Guo, Qin; Dasgupta, Debleena; Yang, Yongkun; Mittelholzer, Christian; Spaccapelo, Roberta; Crisanti, Andrea; Burkhard, Peter; Lanar, David E.

    2012-01-01

    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. PMID:23144750

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

    PubMed Central

    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

  11. Surface Display of Foreign Epitopes on the Lactobacillus brevis S-Layer

    PubMed Central

    Åvall-Jääskeläinen, Silja; Kylä-Nikkilä, Kari; Kahala, Minna; Miikkulainen-Lahti, Terhi; Palva, Airi

    2002-01-01

    So far, the inability to establish viable Lactobacillus surface layer (S-layer) null mutants has hampered the biotechnological applications of Lactobacillus S-layers. In this study, we demonstrate the utilization of Lactobacillus brevis S-layer subunits (SlpA) for the surface display of foreign antigenic epitopes. With an inducible expression system, L. brevis strains producing chimeric S-layers were obtained after testing of four insertion sites in the slpA gene for poliovirus epitope VP1, that comprises 10 amino acids. The epitope insertion site allowing the best surface expression was used for the construction of an integration vector carrying the gene region encoding the c-Myc epitopes from the human c-myc proto-oncogene, which is composed of 11 amino acids. A gene replacement system was optimized for L. brevis and used for the replacement of the wild-type slpA gene with the slpA-c-myc construct. A uniform S-layer, displaying on its surface the desired antigen in all of the S-layer protein subunits, was obtained. The success of the gene replacement and expression of the uniform SlpA-c-Myc recombinant S-layer was confirmed by PCR, Southern blotting MALDI-TOF mass spectrometry, whole-cell enzyme-linked immunosorbent assay, and immunofluorescence microscopy. Furthermore, the integrity of the recombinant S-layer was studied by electron microscopy, which indicated that the S-layer lattice structure was not affected by the presence of c-Myc epitopes. To our knowledge, this is the first successful expression of foreign epitopes in every S-layer subunit of a Lactobacillus S-layer while still maintaining the S-layer lattice structure. PMID:12450814

  12. Surface display of foreign epitopes on the Lactobacillus brevis S-layer.

    PubMed

    Avall-Jääskeläinen, Silja; Kylä-Nikkilä, Kari; Kahala, Minna; Miikkulainen-Lahti, Terhi; Palva, Airi

    2002-12-01

    So far, the inability to establish viable Lactobacillus surface layer (S-layer) null mutants has hampered the biotechnological applications of Lactobacillus S-layers. In this study, we demonstrate the utilization of Lactobacillus brevis S-layer subunits (SlpA) for the surface display of foreign antigenic epitopes. With an inducible expression system, L. brevis strains producing chimeric S-layers were obtained after testing of four insertion sites in the slpA gene for poliovirus epitope VP1, that comprises 10 amino acids. The epitope insertion site allowing the best surface expression was used for the construction of an integration vector carrying the gene region encoding the c-Myc epitopes from the human c-myc proto-oncogene, which is composed of 11 amino acids. A gene replacement system was optimized for L. brevis and used for the replacement of the wild-type slpA gene with the slpA-c-myc construct. A uniform S-layer, displaying on its surface the desired antigen in all of the S-layer protein subunits, was obtained. The success of the gene replacement and expression of the uniform SlpA-c-Myc recombinant S-layer was confirmed by PCR, Southern blotting MALDI-TOF mass spectrometry, whole-cell enzyme-linked immunosorbent assay, and immunofluorescence microscopy. Furthermore, the integrity of the recombinant S-layer was studied by electron microscopy, which indicated that the S-layer lattice structure was not affected by the presence of c-Myc epitopes. To our knowledge, this is the first successful expression of foreign epitopes in every S-layer subunit of a Lactobacillus S-layer while still maintaining the S-layer lattice structure.

  13. Epitope mapping of metuximab on CD147 using phage display and molecular docking.

    PubMed

    He, Bifang; Mao, Canquan; Ru, Beibei; Han, Hesong; Zhou, Peng; Huang, Jian

    2013-01-01

    Metuximab is the generic name of Licartin, a new drug for radioimmunotherapy of hepatocellular carcinoma. Although it is known to be a mouse monoclonal antibody against CD147, the complete epitope mediating the binding of metuximab to CD147 remains unknown. We panned the Ph.D.-12 phage display peptide library against metuximab and got six mimotopes. The following bioinformatics analysis based on mimotopes suggested that metuximab recognizes a conformational epitope composed of more than 20 residues. The residues of its epitope may include T28, V30, K36, L38, K57, F74, D77, S78, D79, D80, Q81, G83, S86, N98, Q100, L101, H102, G103, P104, V131, P132, and K191. The homology modeling of metuximab and the docking of CD147 to metuximab were also performed. Based on the top one docking model, the epitope was predicted to contain 28 residues: AGTVFTTV (23-30), I37, D45, E84, V88, EPMGTANIQLH (92-102), VPP (131-133), Q164, and K191. Almost half of the residues predicted on the basis of mimotope analysis also appear in the docking result, indicating that both results are reliable. As the predicted epitopes of metuximab largely overlap with interfaces of CD147-CD147 interactions, a structural mechanism of metuximab is proposed as blocking the formation of CD147 dimer.

  14. CD4⁺ and CD8⁺ regulatory T cells (Tregs) are elevated and display an active phenotype in patients with chronic HCV mono-infection and HIV/HCV co-infection.

    PubMed

    Hartling, H J; Gaardbo, J C; Ronit, A; Knudsen, L S; Ullum, H; Vainer, B; Clausen, M R; Skogstrand, K; Gerstoft, J; Nielsen, S D

    2012-09-01

    The aim of this study was to examine regulatory T cells (Tregs) in peripheral blood and liver tissue in patients with chronic hepatitis C virus (HCV) mono-infection and in patients with HIV/HCV co-infection. In a cross-sectional study were included 51 patients with chronic HCV infection, 24 patients with HIV/HCV co-infection and 24 healthy individuals. CD4⁺ and CD8⁺ Tregs were determined using flow cytometry. Fibrosis was examined by transient elastography. Inflammation, fibrosis and Tregs were determined in liver biopsies from 12 patients. Increased frequency of CD4⁺ and CD8⁺ Tregs was found in HIV/HCV co-infected patients [median: 6.4% (IQR: 5.7-6.9) and 1.0% (0.7-1.2), respectively] compared to HCV mono-infected patients [5.6% (4.2-6.3), P = 0.01 and 0.5% (0.3-0.7), P < 0.001, respectively]. Furthermore, HCV mono-infected patients had increased frequencies of Tregs compared with healthy controls (P < 0.05). However, no associations between the frequency of Tregs and fibrosis were found. Furthermore, characterization of CD4⁺ Tregs using CD45RA demonstrated a higher frequency of activated Tregs in both HCV mono-infected and HIV/HCV co-infected patients compared with healthy controls. Finally, number of intrahepatic Tregs was associated with both peripheral CD8⁺ Tregs and intrahepatic inflammation. In conclusion, HCV mono-infected patients and particularly HIV/HCV co-infected patients have increased the frequency of CD4⁺ and CD8⁺ Tregs compared with healthy controls. Furthermore, CD4⁺ Tregs in infected patients displayed an active phenotype. Tregs were not associated with fibrosis, but a positive correlation between intrahepatic Tregs and inflammation was found. Taken together, these results suggest a role for Tregs in the pathogenesis of chronic HCV infection.

  15. Infection with Trypanosoma cruzi restricts the repertoire of parasite-specific CD8+ T cells leading to immunodominance.

    PubMed

    Tzelepis, Fanny; de Alencar, Bruna C G; Penido, Marcus L O; Claser, Carla; Machado, Alexandre V; Bruna-Romero, Oscar; Gazzinelli, Ricardo T; Rodrigues, Mauricio M

    2008-02-01

    Interference or competition between CD8(+) T cells restricted by distinct MHC-I molecules can be a powerful means to establish an immunodominant response. However, its importance during infections is still questionable. In this study, we describe that following infection of mice with the human pathogen Trypanosoma cruzi, an immunodominant CD8(+) T cell immune response is developed directed to an H-2K(b)-restricted epitope expressed by members of the trans-sialidase family of surface proteins. To determine whether this immunodominance was exerted over other non-H-2K(b)-restricted epitopes, we measured during infection of heterozygote mice, immune responses to three distinct epitopes, all expressed by members of the trans-sialidase family, recognized by H-2K(b)-, H-2K(k)-, or H-2K(d)-restricted CD8(+) T cells. Infected heterozygote or homozygote mice displayed comparably strong immune responses to the H-2K(b)-restricted immunodominant epitope. In contrast, H-2K(k)- or H-2K(d)-restricted immune responses were significantly impaired in heterozygote infected mice when compared with homozygote ones. This interference was not dependent on the dose of parasite or the timing of infection. Also, it was not seen in heterozygote mice immunized with recombinant adenoviruses expressing T. cruzi Ags. Finally, we observed that the immunodominance was circumvented by concomitant infection with two T. cruzi strains containing distinct immunodominant epitopes, suggesting that the operating mechanism most likely involves competition of T cells for limiting APCs. This type of interference never described during infection with a human parasite may represent a sophisticated strategy to restrict priming of CD8(+) T cells of distinct specificities, avoiding complete pathogen elimination by host effector cells, and thus favoring host parasitism.

  16. Vaccination of stage III/IV melanoma patients with long NY-ESO-1 peptide and CpG-B elicits robust CD8(+) and CD4(+) T-cell responses with multiple specificities including a novel DR7-restricted epitope.

    PubMed

    Baumgaertner, P; Costa Nunes, C; Cachot, A; Maby-El Hajjami, H; Cagnon, L; Braun, M; Derré, L; Rivals, J-P; Rimoldi, D; Gnjatic, S; Abed Maillard, S; Marcos Mondéjar, P; Protti, M P; Romano, E; Michielin, O; Romero, P; Speiser, D E; Jandus, C

    2016-01-01

    Long synthetic peptides and CpG-containing oligodeoxynucleotides are promising components for cancer vaccines. In this phase I trial, 19 patients received a mean of 8 (range 1-12) monthly vaccines s.c. composed of the long synthetic NY-ESO-179-108 peptide and CpG-B (PF-3512676), emulsified in Montanide ISA-51. In 18/18 evaluable patients, vaccination induced antigen-specific CD8(+) and CD4(+) T-cell and antibody responses, starting early after initiation of immunotherapy and lasting at least one year. The T-cells responded antigen-specifically, with strong secretion of IFNγ and TNFα, irrespective of patients' HLAs. The most immunogenic regions of the vaccine peptide were NY-ESO-189-102 for CD8(+) and NY-ESO-183-99 for CD4(+) T-cells. We discovered a novel and highly immunogenic epitope (HLA-DR7/NY-ESO-187-99); 7/7 HLA-DR7(+) patients generated strong CD4(+) T-cell responses, as detected directly ex vivo with fluorescent multimers. Thus, vaccination with the long synthetic NY-ESO-179-108 peptide combined with the strong immune adjuvant CpG-B induced integrated, robust and functional CD8(+) and CD4(+) T-cell responses in melanoma patients, supporting the further development of this immunotherapeutic approach.

  17. Promiscuous Recognition of a Trypanosoma cruzi CD8+ T Cell Epitope among HLA-A2, HLA-A24 and HLA-A1 Supertypes in Chagasic Patients

    PubMed Central

    Guzmán, Fanny; Rosas, Fernando; Thomas, M. Carmen; López, Manuel Carlos; González, John Mario; Cuéllar, Adriana; Puerta, Concepción J.

    2016-01-01

    Background TcTLE is a nonamer peptide from Trypanosoma cruzi KMP-11 protein that is conserved among different parasite strains and that is presented by different HLA-A molecules from the A2 supertype. Because peptides presented by several major histocompatibility complex (MHC) supertypes are potential targets for immunotherapy, the aim of this study was to determine whether MHC molecules other than the A2 supertype present the TcTLE peptide. Methodology/Principal Findings From 36 HLA-A2-negative chagasic patients, the HLA-A genotypes of twenty-eight patients with CD8+ T cells that recognized the TcTLE peptide using tetramer (twenty) or functional (eight) assays, were determined. SSP-PCR was used to identify the A locus and the allelic variants. Flow cytometry was used to analyze the frequency of TcTLE-specific CD8+ T cells, and their functional activity (IFN-γ, TNFα, IL-2, perforin, granzyme and CD107a/b production) was induced by exposure to the TcTLE peptide. All patients tested had TcTLE-specific CD8+ T cells with frequencies ranging from 0.07–0.37%. Interestingly, seven of the twenty-eight patients had HLA-A homozygous alleles: A*24 (5 patients), A*23 (1 patient) and A*01 (1 patient), which belong to the A24 and A1 supertypes. In the remaining 21 patients with HLA-A heterozygous alleles, the most prominent alleles were A24 and A68. The most common allele sub-type was A*2402 (sixteen patients), which belongs to the A24 supertype, followed by A*6802 (six patients) from the A2 supertype. Additionally, the A*3002/A*3201 alleles from the A1 supertype were detected in one patient. All patients presented CD8+ T cells producing at least one cytokine after TcTLE peptide stimulation. Conclusion/Significance These results show that TcTLE is a promiscuous peptide that is presented by the A24 and A1 supertypes, in addition to the A2 supertype, suggesting its potential as a target for immunotherapy. PMID:26974162

  18. The Crystal Structure of CD8alpha,Beta in Complex With YTS156.7.7 Fab And Interaction With Other CD8 Antibodies Define the Binding Mode of CD8alpha,Beta to MHC Class I

    SciTech Connect

    Shore, D.A.; Issafras, H.; Landais, E.; Teyton, L.; Wilson, I.A.

    2009-05-27

    The CD8{alpha}{beta} heterodimer interacts with class I pMHC on antigen-presenting cells as a co-receptor for TCR-mediated activation of cytotoxic T cells. To characterize this immunologically important interaction, we used monoclonal antibodies (mAbs) specific to either CD8{alpha} or CD8{beta} to probe the mechanism of CD8{alpha}{beta} binding to pMHCI. The YTS156.7 mAb inhibits this interaction and blocks T cell activation. To elucidate the molecular basis for this inhibition, the crystal structure of the CD8{alpha}{beta} immunoglobulin-like ectodomains were determined in complex with mAb YTS156.7 Fab at 2.7 {angstrom} resolution. The YTS156.7 epitope on CD8{beta} was identified and implies that residues in the CDR1 and CDR2-equivalent loops of CD8{beta} are occluded upon binding to class I pMHC. To further characterize the pMHCI/CD8{alpha}{beta} interaction, binding of class I tetramers to CD8{alpha}{beta} on the surface of T cells was assessed in the presence of anti-CD8 mAbs. In contrast to YTS156.7, mAb YTS105.18, which is specific for CD8{alpha}, does not inhibit binding of CD8{alpha}{beta} to class I tetramers, indicating the YTS105.18 epitope is not occluded in the pMHCI/CD8{alpha}{beta} complex. Together, these data indicate a model for the pMHCI/CD8{alpha}{beta} interaction similar to that observed for CD8{alpha}{alpha} in the CD8{alpha}{alpha}/pMHCI complex, but in which CD8{alpha} occupies the lower orientation (membrane proximal to the antigen presenting cell), and CD8{beta} occupies the upper position (membrane distal). The implication of this molecular assembly for the function of CD8{alpha}{beta} in T cell activation is discussed.

  19. Expression and immunological characterization of cardamom mosaic virus coat protein displaying HIV gp41 epitopes.

    PubMed

    Damodharan, Subha; Gujar, Ravindra; Pattabiraman, Sathyamurthy; Nesakumar, Manohar; Hanna, Luke Elizabeth; Vadakkuppattu, Ramanathan D; Usha, Ramakrishnan

    2013-05-01

    The coat protein of cardamom mosaic virus (CdMV), a member of the genus Macluravirus, assembles into virus-like particles when expressed in an Escherichia coli expression system. The N and C-termini of the coat protein were engineered with the Kennedy peptide and the 2F5 and 4E10 epitopes of gp41 of HIV. The chimeric proteins reacted with sera from HIV positive persons and also stimulated secretion of cytokines by peripheral blood mononuclear cells from these persons. Thus, a system based on the coat protein of CdMV can be used to display HIV-1 antigens.

  20. The Breadth of Synthetic Long Peptide Vaccine-Induced CD8+ T Cell Responses Determines the Efficacy against Mouse Cytomegalovirus Infection

    PubMed Central

    Panagioti, Eleni; Redeker, Anke; van Duikeren, Suzanne; Franken, Kees LMC; Drijfhout, Jan Wouter; van der Burg, Sjoerd H.

    2016-01-01

    There is an ultimate need for efficacious vaccines against human cytomegalovirus (HCMV), which causes severe morbidity and mortality among neonates and immunocompromised individuals. In this study we explored synthetic long peptide (SLP) vaccination as a platform modality to protect against mouse CMV (MCMV) infection in preclinical mouse models. In both C57BL/6 and BALB/c mouse strains, prime-booster vaccination with SLPs containing MHC class I restricted epitopes of MCMV resulted in the induction of strong and polyfunctional (i.e., IFN-γ+, TNF+, IL-2+) CD8+ T cell responses, equivalent in magnitude to those induced by the virus itself. SLP vaccination initially led to the formation of effector CD8+ T cells (KLRG1hi, CD44hi, CD127lo, CD62Llo), which eventually converted to a mixed central and effector-memory T cell phenotype. Markedly, the magnitude of the SLP vaccine-induced CD8+ T cell response was unrelated to the T cell functional avidity but correlated to the naive CD8+ T cell precursor frequency of each epitope. Vaccination with single SLPs displayed various levels of long-term protection against acute MCMV infection, but superior protection occurred after vaccination with a combination of SLPs. This finding underlines the importance of the breadth of the vaccine-induced CD8+ T cell response. Thus, SLP-based vaccines could be a potential strategy to prevent CMV-associated disease. PMID:27637068

  1. Multivalent display of minimal Clostridium difficile glycan epitopes mimics antigenic properties of larger glycans

    PubMed Central

    Broecker, Felix; Hanske, Jonas; Martin, Christopher E.; Baek, Ju Yuel; Wahlbrink, Annette; Wojcik, Felix; Hartmann, Laura; Rademacher, Christoph; Anish, Chakkumkal; Seeberger, Peter H.

    2016-01-01

    Synthetic cell-surface glycans are promising vaccine candidates against Clostridium difficile. The complexity of large, highly antigenic and immunogenic glycans is a synthetic challenge. Less complex antigens providing similar immune responses are desirable for vaccine development. Based on molecular-level glycan–antibody interaction analyses, we here demonstrate that the C. difficile surface polysaccharide-I (PS-I) can be resembled by multivalent display of minimal disaccharide epitopes on a synthetic scaffold that does not participate in binding. We show that antibody avidity as a measure of antigenicity increases by about five orders of magnitude when disaccharides are compared with constructs containing five disaccharides. The synthetic, pentavalent vaccine candidate containing a peptide T-cell epitope elicits weak but highly specific antibody responses to larger PS-I glycans in mice. This study highlights the potential of multivalently displaying small oligosaccharides to achieve antigenicity characteristic of larger glycans. The approach may result in more cost-efficient carbohydrate vaccines with reduced synthetic effort. PMID:27091615

  2. Multivalent display of minimal Clostridium difficile glycan epitopes mimics antigenic properties of larger glycans.

    PubMed

    Broecker, Felix; Hanske, Jonas; Martin, Christopher E; Baek, Ju Yuel; Wahlbrink, Annette; Wojcik, Felix; Hartmann, Laura; Rademacher, Christoph; Anish, Chakkumkal; Seeberger, Peter H

    2016-04-19

    Synthetic cell-surface glycans are promising vaccine candidates against Clostridium difficile. The complexity of large, highly antigenic and immunogenic glycans is a synthetic challenge. Less complex antigens providing similar immune responses are desirable for vaccine development. Based on molecular-level glycan-antibody interaction analyses, we here demonstrate that the C. difficile surface polysaccharide-I (PS-I) can be resembled by multivalent display of minimal disaccharide epitopes on a synthetic scaffold that does not participate in binding. We show that antibody avidity as a measure of antigenicity increases by about five orders of magnitude when disaccharides are compared with constructs containing five disaccharides. The synthetic, pentavalent vaccine candidate containing a peptide T-cell epitope elicits weak but highly specific antibody responses to larger PS-I glycans in mice. This study highlights the potential of multivalently displaying small oligosaccharides to achieve antigenicity characteristic of larger glycans. The approach may result in more cost-efficient carbohydrate vaccines with reduced synthetic effort.

  3. Tomato bushy stunt virus (TBSV), a versatile platform for polyvalent display of antigenic epitopes and vaccine design

    SciTech Connect

    Kumar, Shantanu; Ochoa, Wendy; Singh, Pratik; Hsu, Catherine; Schneemann, Anette; Manchester, Marianne; Olson, Mark; Reddy, Vijay

    2009-05-25

    Viruses-like particles (VLPs) are frequently being used as platforms for polyvalent display of foreign epitopes of interest on their capsid surface to improve their presentation enhancing the antigenicity and host immune response. In the present study, we used the VLPs of Tomato bushy stunt virus (TBSV), an icosahedral plant virus, as a platform to display 180 copies of 16 amino acid epitopes of ricin toxin fused to the C-terminal end of a modified TBSV capsid protein (NDELTA52). Expression of the chimeric recombinant protein in insect cells resulted in spontaneous assembly of VLPs displaying the ricin epitope. Cryo-electron microscopy and image reconstruction of the chimeric VLPs at 22 A resolution revealed the locations and orientation of the ricin epitope exposed on the TBSV capsid surface. Furthermore, injection of chimeric VLPs into mice generated antisera that detected the native ricin toxin. The ease of fusing of short peptides of 15-20 residues and their ability to form two kinds (T = 1, T = 3) of bio-nanoparticles that result in the display of 60 or 180 copies of less constrained and highly exposed antigenic epitopes makes TBSV an attractive and versatile display platform for vaccine design.

  4. Human influenza viruses and CD8(+) T cell responses.

    PubMed

    Grant, Emma J; Quiñones-Parra, Sergio M; Clemens, E Bridie; Kedzierska, Katherine

    2016-02-01

    Influenza A viruses (IAVs) cause significant morbidity and mortality worldwide, despite new strain-specific vaccines being available annually. As IAV-specific CD8(+) T cells promote viral control in the absence of neutralizing antibodies, and can mediate cross-reactive immunity toward distinct IAVs to drive rapid recovery from both mild and severe influenza disease, there is great interest in developing a universal T cell vaccine. However, despite detailed studies in mouse models of influenza virus infection, there is still a paucity of data on human epitope-specific CD8(+) T cell responses to IAVs. This review focuses on our current understanding of human CD8(+) T cell immunity against distinct IAVs and discusses the possibility of achieving a CD8(+) T cell mediated-vaccine that protects against multiple, distinct IAV strains across diverse human populations. We also review the importance of CD8(+) T cell immunity in individuals highly susceptible to severe influenza infection, including those hospitalised with influenza, the elderly and Indigenous populations.

  5. Memory CD8(+) T cells elicited by HIV-1 lipopeptide vaccines display similar phenotypic profiles but differences in term of magnitude and multifunctionality compared with FLU- or EBV-specific memory T cells in humans.

    PubMed

    Figueiredo, Suzanne; Charmeteau, Benedicte; Surenaud, Mathieu; Salmon, Dominique; Launay, Odile; Guillet, Jean-Gérard; Hosmalin, Anne; Gahery, Hanne

    2014-01-16

    Differentiation marker, multifunctionality and magnitude analyses of specific-CD8(+) memory T cells are crucial to improve development of HIV vaccines designed to generate cell-mediated immunity. Therefore, we fully characterized the HIV-specific CD8(+) T cell responses induced in volunteers vaccinated with HIV lipopeptide vaccines for phenotypic markers, tetramer staining, cytokine secretion, and cytotoxic activities. The frequency of ex vivo CD8(+) T cells elicited by lipopeptide vaccines is very rare and central-memory phenotype and functions of these cells were been shown to be important in AIDS immunity. So, we expanded them using specific peptides to compare the memory T cell responses induced in volunteers by HIV vaccines with responses to influenza (FLU) or Epstein Barr virus (EBV). By analyzing the differentiation state of IFN-γ-secreting CD8(+) T cells, we found a CCR7(-)CD45RA(-)CD28(+int)/CD28(-) profile (>85%) belonging to a subset of intermediate-differentiated effector T cells for HIV, FLU, and EBV. We then assessed the quality of the response by measuring various T cell functions. The percentage of single IFN-γ T cell producers in response to HIV was 62% of the total of secreting T cells compared with 35% for FLU and EBV, dual and triple (IFN-γ/IL-2/CD107a) T cell producers could also be detected but at lower levels (8% compared with 37%). Finally, HIV-specific T cells secreted IFN-γ and TNF-α, but not the dual combination like FLU- and EBV-specific T cells. Thus, we found that the functional profile and magnitude of expanded HIV-specific CD8(+) T precursors were more limited than those of to FLU- and EBV-specific CD8(+) T cells. These data show that CD8(+) T cells induced by these HIV vaccines have a similar differentiation profile to FLU and EBV CD8(+) T cells, but that the vaccine potency to induce multifunctional T cells needs to be increased in order to improve vaccination strategies.

  6. Putative phage-display epitopes of the porcine epidemic diarrhea virus S1 protein and their anti-viral activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Porcine epidemic diarrhea virus (PEDV) is a pathogen of swine that causes severe diarrhea and dehydration resulting in substantial morbidity and mortality in newborn piglets. Phage display is a technique with wide application, in particular, the identification of key antigen epitopes for the develop...

  7. Rabbit hemorrhagic disease virus capsid, a versatile platform for foreign B-cell epitope display inducing protective humoral immune responses

    PubMed Central

    Moreno, Noelia; Mena, Ignacio; Angulo, Iván; Gómez, Yolanda; Crisci, Elisa; Montoya, María; Castón, José R.; Blanco, Esther; Bárcena, Juan

    2016-01-01

    Virus-like particles (VLPs), comprised of viral structural proteins devoid of genetic material, are tunable nanoparticles that can be chemically or genetically engineered, to be used as platforms for multimeric display of foreign antigens. Here, we report the engineering of chimeric VLPs, derived from rabbit hemorrhagic disease virus (RHDV) for presentation of foreign B-cell antigens to the immune system. The RHDV capsid comprises 180 copies of a single capsid subunit (VP60). To evaluate the ability of chimeric RHDV VLPs to elicit protective humoral responses against foreign antigens, we tested two B-cell epitopes: a novel neutralizing B-cell epitope, derived from feline calicivirus capsid protein, and a well characterized B-cell epitope from the extracellular domain of influenza A virus M2 protein (M2e). We generated sets of chimeric RHDV VLPs by insertion of the foreign B-cell epitopes at three different locations within VP60 protein (which involved different levels of surface accessibility) and in different copy numbers per site. The immunogenic potential of the chimeric VLPs was analyzed in the mouse model. The results presented here indicated that chimeric RHDV VLPs elicit potent protective humoral responses against displayed foreign B-cell epitopes, demonstrated by both, in vitro neutralization and in vivo protection against a lethal challenge. PMID:27549017

  8. Heterogeneous differentiation patterns of individual CD8+ T cells.

    PubMed

    Gerlach, Carmen; Rohr, Jan C; Perié, Leïla; van Rooij, Nienke; van Heijst, Jeroen W J; Velds, Arno; Urbanus, Jos; Naik, Shalin H; Jacobs, Heinz; Beltman, Joost B; de Boer, Rob J; Schumacher, Ton N M

    2013-05-03

    Upon infection, antigen-specific CD8(+) T lymphocyte responses display a highly reproducible pattern of expansion and contraction that is thought to reflect a uniform behavior of individual cells. We tracked the progeny of individual mouse CD8(+) T cells by in vivo lineage tracing and demonstrated that, even for T cells bearing identical T cell receptors, both clonal expansion and differentiation patterns are heterogeneous. As a consequence, individual naïve T lymphocytes contributed differentially to short- and long-term protection, as revealed by participation of their progeny during primary versus recall infections. The discordance in fate of individual naïve T cells argues against asymmetric division as a singular driver of CD8(+) T cell heterogeneity and demonstrates that reproducibility of CD8(+) T cell responses is achieved through population averaging.

  9. Human immunome, bioinformatic analyses using HLA supermotifs and the parasite genome, binding assays, studies of human T cell responses, and immunization of HLA-A*1101 transgenic mice including novel adjuvants provide a foundation for HLA-A03 restricted CD8+T cell epitope based, adjuvanted vaccine protective against Toxoplasma gondii

    PubMed Central

    2010-01-01

    Background Toxoplasmosis causes loss of life, cognitive and motor function, and sight. A vaccine is greatly needed to prevent this disease. The purpose of this study was to use an immmunosense approach to develop a foundation for development of vaccines to protect humans with the HLA-A03 supertype. Three peptides had been identified with high binding scores for HLA-A03 supertypes using bioinformatic algorhythms, high measured binding affinity for HLA-A03 supertype molecules, and ability to elicit IFN-γ production by human HLA-A03 supertype peripheral blood CD8+ T cells from seropositive but not seronegative persons. Results Herein, when these peptides were administered with the universal CD4+T cell epitope PADRE (AKFVAAWTLKAAA) and formulated as lipopeptides, or administered with GLA-SE either alone, or with Pam2Cys added, we found we successfully created preparations that induced IFN-γ and reduced parasite burden in HLA-A*1101(an HLA-A03 supertype allele) transgenic mice. GLA-SE is a novel emulsified synthetic TLR4 ligand that is known to facilitate development of T Helper 1 cell (TH1) responses. Then, so our peptides would include those expressed in tachyzoites, bradyzoites and sporozoites from both Type I and II parasites, we used our approaches which had identified the initial peptides. We identified additional peptides using bioinformatics, binding affinity assays, and study of responses of HLA-A03 human cells. Lastly, we found that immunization of HLA-A*1101 transgenic mice with all the pooled peptides administered with PADRE, GLA-SE, and Pam2Cys is an effective way to elicit IFN-γ producing CD8+ splenic T cells and protection. Immunizations included the following peptides together: KSFKDILPK (SAG1224-232); AMLTAFFLR (GRA6164-172); RSFKDLLKK (GRA7134-142); STFWPCLLR (SAG2C13-21); SSAYVFSVK(SPA250-258); and AVVSLLRLLK(SPA89-98). This immunization elicited robust protection, measured as reduced parasite burden using a luciferase transfected parasite

  10. MimoPro: a more efficient Web-based tool for epitope prediction using phage display libraries

    PubMed Central

    2011-01-01

    Background A B-cell epitope is a group of residues on the surface of an antigen which stimulates humoral responses. Locating these epitopes on antigens is important for the purpose of effective vaccine design. In recent years, mapping affinity-selected peptides screened from a random phage display library to the native epitope has become popular in epitope prediction. These peptides, also known as mimotopes, share the similar structure and function with the corresponding native epitopes. Great effort has been made in using this similarity between such mimotopes and native epitopes in prediction, which has resulted in better outcomes than statistics-based methods can. However, it cannot maintain a high degree of satisfaction in various circumstances. Results In this study, we propose a new method that maps a group of mimotopes back to a source antigen so as to locate the interacting epitope on the antigen. The core of this method is a searching algorithm that is incorporated with both dynamic programming (DP) and branch and bound (BB) optimization and operated on a series of overlapping patches on the surface of a protein. These patches are then transformed to a number of graphs using an adaptable distance threshold (ADT) regulated by an appropriate compactness factor (CF), a novel parameter proposed in this study. Compared with both Pep-3D-Search and PepSurf, two leading graph-based search tools, on average from the results of 18 test cases, MimoPro, the Web-based implementation of our proposed method, performed better in sensitivity, precision, and Matthews correlation coefficient (MCC) than both did in epitope prediction. In addition, MimoPro is significantly faster than both Pep-3D-Search and PepSurf in processing. Conclusions Our search algorithm designed for processing well constructed graphs using an ADT regulated by CF is more sensitive and significantly faster than other graph-based approaches in epitope prediction. MimoPro is a viable alternative to both

  11. Insert engineering and solubility screening improves recovery of virus-like particle subunits displaying hydrophobic epitopes

    PubMed Central

    Abidin, R S; Lua, L H L; Middelberg, A P J; Sainsbury, F

    2015-01-01

    The Polyomavirus coat protein, VP1 has been developed as an epitope presentation system able to provoke humoral immunity against a variety of pathogens, such as Influenza and Group A Streptococcus. The ability of the system to carry cytotoxic T cell epitopes on a surface-exposed loop and the impact on protein solubility has not been examined. Four variations of three selected epitopes were cloned into surface-exposed loops of VP1, and expressed in Escherichia coli. VP1 pentamers, also known as capsomeres, were purified via a glutathione-S-transferase tag. Size exclusion chromatography indicated severe aggregation of the recombinant VP1 during enzymatic tag removal resulting from the introduction the hydrophobic epitopes. Inserts were modified to possess double aspartic acid residues at each end of the hydrophobic epitopes and a high-throughput buffer condition screen was implemented with protein aggregation monitored during tag removal by spectrophotometry and dynamic light scattering. These analyses showed that the insertion of charged residues at the extremities of epitopes could improve solubility of capsomeres and revealed multiple windows of opportunity for further condition optimization. A combination of epitope design, pH optimization, and the additive l-arginine permitted the recovery of soluble VP1 pentamers presenting hydrophobic epitopes and their subsequent assembly into virus-like particles. PMID:26401641

  12. Globular Head-Displayed Conserved Influenza H1 Hemagglutinin Stalk Epitopes Confer Protection against Heterologous H1N1 Virus

    PubMed Central

    Klausberger, Miriam; Tscheliessnig, Rupert; Neff, Silke; Nachbagauer, Raffael; Wohlbold, Teddy John; Wilde, Monika; Palmberger, Dieter; Krammer, Florian; Jungbauer, Alois; Grabherr, Reingard

    2016-01-01

    Significant genetic variability in the head region of the influenza A hemagglutinin, the main target of current vaccines, makes it challenging to develop a long-lived seasonal influenza prophylaxis. Vaccines based on the conserved hemagglutinin stalk domain might provide broader cross-reactive immunity. However, this region of the hemagglutinin is immunosubdominant to the head region. Peptide-based vaccines have gained much interest as they allow the immune system to focus on relevant but less immunogenic epitopes. We developed a novel influenza A hemagglutinin-based display platform for H1 hemagglutinin stalk peptides that we identified in an epitope mapping assay using human immune sera and synthetic HA peptides. Flow cytometry and competition assays suggest that the identified stalk sequences do not recapitulate the epitopes of already described broadly neutralizing stalk antibodies. Vaccine constructs displaying 25-mer stalk sequences provided up to 75% protection from lethal heterologous virus challenge in BALB/c mice and induced antibody responses against the H1 hemagglutinin. The developed platform based on a vaccine antigen has the potential to be either used as stand-alone or as prime-vaccine in combination with conventional seasonal or pandemic vaccines for the amplification of stalk-based cross-reactive immunity in humans or as platform to evaluate the relevance of viral peptides/epitopes for protection against influenza virus infection. PMID:27088239

  13. Oral administration of genetically modified Bifidobacterium displaying HCV-NS3 multi-epitope fusion protein could induce an HCV-NS3-specific systemic immune response in mice.

    PubMed

    Takei, Saki; Omoto, Chika; Kitagawa, Koichi; Morishita, Naoya; Katayama, Takane; Shigemura, Katsumi; Fujisawa, Masato; Kawabata, Masato; Hotta, Hak; Shirakawa, Toshiro

    2014-05-23

    More than 170 million people worldwide are chronic HCV (Hepatitis C virus) carriers, and about 30% of them will develop progressive liver disease, such as cirrhosis and hepatocellular carcinoma. A combination of pegylated interferon-α with ribavirin, the standard treatment for HCV infection, has been effective in fewer than 50% of patients infected with HCV genotype 1. A strong T cell response against the nonstructural protein 3 (NS3) is important for recovery from acute HCV infection, and an early multi-specific CD4+ helper and CD8+ cytotoxic T cell response is critical for HCV clearance. In the present study, we successfully constructed a genetically modified Bifidobacterium longum (B. longum) displaying recombinant HCV-NS3 peptides containing some CD4 and CD8 epitopes located in the HCV-NS3 region as an oral vaccine against chronic HCV infection. The oral administration of this vaccine could induce NS3-specific immune responses in mice through intestinal mucosal immunity. Our findings suggest that this novel oral vaccine has great potential as a novel oral vaccine against chronic HCV infection.

  14. Specificity and Dynamics of Effector and Memory CD8 T Cell Responses in Human Tick-Borne Encephalitis Virus Infection

    PubMed Central

    Blom, Kim; Braun, Monika; Pakalniene, Jolita; Dailidyte, Laura; Béziat, Vivien; Lampen, Margit H.; Klingström, Jonas; Lagerqvist, Nina; Kjerstadius, Torbjörn; Michaëlsson, Jakob; Lindquist, Lars; Ljunggren, Hans-Gustaf; Sandberg, Johan K.; Mickiene, Aukse; Gredmark-Russ, Sara

    2015-01-01

    Tick-borne encephalitis virus (TBEV) is transferred to humans by ticks. The virus causes tick-borne encephalitis (TBE) with symptoms such as meningitis and meningoencephalitis. About one third of the patients suffer from long-lasting sequelae after clearance of the infection. Studies of the immune response during TBEV-infection are essential to the understanding of host responses to TBEV-infection and for the development of therapeutics. Here, we studied in detail the primary CD8 T cell response to TBEV in patients with acute TBE. Peripheral blood CD8 T cells mounted a considerable response to TBEV-infection as assessed by Ki67 and CD38 co-expression. These activated cells showed a CD45RA-CCR7-CD127- phenotype at day 7 after hospitalization, phenotypically defining them as effector cells. An immunodominant HLA-A2-restricted TBEV epitope was identified and utilized to study the characteristics and temporal dynamics of the antigen-specific response. The functional profile of TBEV-specific CD8 T cells was dominated by variants of mono-functional cells as the effector response matured. Antigen-specific CD8 T cells predominantly displayed a distinct Eomes+Ki67+T-bet+ effector phenotype at the peak of the response, which transitioned to an Eomes-Ki67-T-bet+ phenotype as the infection resolved and memory was established. These transcription factors thus characterize and discriminate stages of the antigen-specific T cell response during acute TBEV-infection. Altogether, CD8 T cells responded strongly to acute TBEV infection and passed through an effector phase, prior to gradual differentiation into memory cells with distinct transcription factor expression-patterns throughout the different phases. PMID:25611738

  15. Chimeric Virus-Like Particle Vaccines Displaying Conserved Enterovirus 71 Epitopes Elicit Protective Neutralizing Antibodies in Mice through Divergent Mechanisms

    PubMed Central

    Ye, Xiaohua; Ku, Zhiqiang; Liu, Qingwei; Wang, Xiaoli; Shi, Jinping; Zhang, Yunfang; Kong, Liangliang; Cong, Yao

    2014-01-01

    Enterovirus 71 (EV71) is a major causative agent of hand, food, and mouth disease, which frequently occurs in young children. Since there are 11 subgenotypes (A, B1 to B5, and C1 to C5) within EV71, an EV71 vaccine capable of protecting against all of these subgenotypes is desirable. We report here the vaccine potential and protective mechanism of two chimeric virus-like particles (VLPs) presenting conserved neutralizing epitopes of EV71. We show that fusions of hepatitis B core antigen (HBc) with the SP55 or SP70 epitope of EV71, designated HBcSP55 and HBcSP70, respectively, can be rapidly generated and self-assembled into VLPs with the epitopes displayed on the surface. Immunization with the chimeric VLPs induced carrier- and epitope-specific antibody responses in mice. Anti-HBcSP55 and anti-HBcSP70 sera, but not anti-HBc sera, were able to neutralize in vitro multiple genotypes and strains of EV71. Importantly, passive immunization with anti-HBcSP55 or anti-HBcSP70 sera protected neonatal mice against lethal EV71 infections. Interestingly, anti-HBcSP70 sera could inhibit EV71 attachment to susceptible cells, whereas anti-HBcSP55 sera could not. However, both antisera were able to neutralize EV71 infection in vitro at the postattachment stage. The divergent mechanism of neutralization and protection conferred by anti-SP70 and anti-SP55 sera is in part attributed to their respective ability to bind authentic viral particles. Collectively, our study not only demonstrates that chimeric VLPs displaying the SP55 and SP70 epitopes are promising candidates for a broad-spectrum EV71 vaccine but also reveals distinct mechanisms of neutralization by the SP55- and SP70-targeted antibodies. PMID:24131712

  16. High-throughput sequencing enhanced phage display enables the identification of patient-specific epitope motifs in serum

    PubMed Central

    Christiansen, Anders; Kringelum, Jens V.; Hansen, Christian S.; Bøgh, Katrine L.; Sullivan, Eric; Patel, Jigar; Rigby, Neil M.; Eiwegger, Thomas; Szépfalusi, Zsolt; Masi, Federico de; Nielsen, Morten; Lund, Ole; Dufva, Martin

    2015-01-01

    Phage display is a prominent screening technique with a multitude of applications including therapeutic antibody development and mapping of antigen epitopes. In this study, phages were selected based on their interaction with patient serum and exhaustively characterised by high-throughput sequencing. A bioinformatics approach was developed in order to identify peptide motifs of interest based on clustering and contrasting to control samples. Comparison of patient and control samples confirmed a major issue in phage display, namely the selection of unspecific peptides. The potential of the bioinformatic approach was demonstrated by identifying epitopes of a prominent peanut allergen, Ara h 1, in sera from patients with severe peanut allergy. The identified epitopes were confirmed by high-density peptide micro-arrays. The present study demonstrates that high-throughput sequencing can empower phage display by (i) enabling the analysis of complex biological samples, (ii) circumventing the traditional laborious picking and functional testing of individual phage clones and (iii) reducing the number of selection rounds. PMID:26246327

  17. Phage display and hybridoma generation of antibodies to human CXCR2 yields antibodies with distinct mechanisms and epitopes.

    PubMed

    Rossant, Christine J; Carroll, Danielle; Huang, Ling; Elvin, John; Neal, Frances; Walker, Edward; Benschop, Joris J; Kim, Eldar E; Barry, Simon T; Vaughan, Tristan J

    2014-01-01

    Generation of functional antibodies against integral membrane proteins such as the G-protein coupled receptor CXCR2 is technically challenging for several reasons, including limited epitope accessibility, the requirement for a lipid environment to maintain structure and their existence in dynamic conformational states. Antibodies to human CXCR2 were generated by immunization in vivo and by in vitro selection methods. Whole cell immunization of transgenic mice and screening of phage display libraries using CXCR2 magnetic proteoliposomes resulted in the isolation of antibodies with distinct modes of action. The hybridoma-derived antibody fully inhibited IL-8 and Gro-α responses in calcium flux and β-arrestin recruitment assays. The phage-display derived antibodies were allosteric antagonists that showed ligand dependent differences in functional assays. The hybridoma and phage display antibodies did not cross-compete in epitope competition assays and mapping using linear and CLIPS peptides confirmed that they recognized distinct epitopes of human CXCR2. This illustrates the benefits of using parallel antibody isolation approaches with different antigen presentation methods to successfully generate functionally and mechanistically diverse antagonistic antibodies to human CXCR2. The method is likely to be broadly applicable to other complex membrane proteins.

  18. HIV-1-Specific CD8 T Cells Exhibit Limited Cross-Reactivity during Acute Infection.

    PubMed

    Du, Victor Y; Bansal, Anju; Carlson, Jonathan; Salazar-Gonzalez, Jesus F; Salazar, Maria G; Ladell, Kristin; Gras, Stephanie; Josephs, Tracy M; Heath, Sonya L; Price, David A; Rossjohn, Jamie; Hunter, Eric; Goepfert, Paul A

    2016-04-15

    Prior work has demonstrated that HIV-1-specific CD8 T cells can cross-recognize variant epitopes. However, most of these studies were performed in the context of chronic infection, where the presence of viral quasispecies makes it difficult to ascertain the true nature of the original antigenic stimulus. To overcome this limitation, we evaluated the extent of CD8 T cell cross-reactivity in patients with acute HIV-1 clade B infection. In each case, we determined the transmitted founder virus sequence to identify the autologous epitopes restricted by individual HLA class I molecules. Our data show that cross-reactive CD8 T cells are infrequent during the acute phase of HIV-1 infection. Moreover, in the uncommon instances where cross-reactive responses were detected, the variant epitopes were poorly recognized in cytotoxicity assays. Molecular analysis revealed that similar antigenic structures could be cross-recognized by identical CD8 T cell clonotypes mobilized in vivo, yet even subtle differences in a single TCR-accessible peptide residue were sufficient to disrupt variant-specific reactivity. These findings demonstrate that CD8 T cells are highly specific for autologous epitopes during acute HIV-1 infection. Polyvalent vaccines may therefore be required to provide optimal immune cover against this genetically labile pathogen.

  19. Identification of a Conserved B-cell Epitope on Reticuloendotheliosis Virus Envelope Protein by Screening a Phage-displayed Random Peptide Library

    PubMed Central

    Xue, Mei; Shi, Xingming; Zhang, Jing; Zhao, Yan; Cui, Hongyu; Hu, Shunlei; Gao, Hongbo; Cui, Xianlan; Wang, Yun-Feng

    2012-01-01

    Background The gp90 protein of avian reticuloendotheliosis-associated virus (REV-A) is an important envelope glycoprotein, which is responsible for inducing protective antibody immune responses in animals. B-cell epitopes on the gp90 protein of REV have not been well studied and reported. Methods and Results This study describes the identification of a linear B-cell epitope on the gp90 protein by screening a phage-displayed 12-mer random peptide library with the neutralizing monoclonal antibody (mAb) A9E8 directed against the gp90. The mAb A9E8 recognized phages displaying peptides with the consensus motif SVQYHPL. Amino acid sequence of the motif exactly matched 213SVQYHPL219 of the gp90. Further identification of the displayed B cell epitope was conducted using a set of truncated peptides expressed as GST fusion proteins and the Western blot results indicated that 213SVQYHPL219 was the minimal determinant of the linear B cell epitope recognized by the mAb A9E8. Moreover, an eight amino acid peptide SVQYHPLA was proven to be the minimal unit of the epitope with the maximal binding activity to mAb A9E8. The REV-A-positive chicken serum reacted with the minimal linear epitopes in Western blot, revealing the importance of the eight amino acids of the epitope in antibody-epitope binding activity. Furthermore, we found that the epitope is a common motif shared among REV-A and other members of REV group. Conclusions and Significance We identified 213SVQYHPL219 as a gp90-specific linear B-cell epitope recognized by the neutralizing mAb A9E8. The results in this study may have potential applications in development of diagnostic techniques and epitope-based marker vaccines against REV-A and other viruses of the REV group. PMID:23185456

  20. Rapid Conformational Epitope Mapping of anti-gp120 Antibodies with a Designed Mutant Panel Displayed on Yeast

    PubMed Central

    Mata-Fink, Jordi; Kriegsman, Barry; Xin, Yu Hui; Zhu, Hanna; Hanson, Melissa; Irvine, Darrell J.; Wittrup, K. Dane

    2013-01-01

    gp120 is a substrate for protein engineering both for HIV immunogen design and as a bait for isolating anti-HIV antibodies from patient samples. In this work we describe the display of a stripped core gp120 on the yeast cell surface. Validation against a panel of neutralizing antibodies confirms that yeast-displayed gp120 presents the CD4 binding site in the correct conformation. We map the epitope of the broadly neutralizing anti-gp120 antibody VRC01 using both a random mutagenesis library and a defined mutant panel, and find the resultant epitope maps are consistent with one another and with the crystallographically identified contact residues. Mapping the VRC01-competitive antibodies b12 and b13 reveals energetic differences in their epitopes that are not obvious from existing crystal structures. These data suggest mutation sets that abrogate binding to broadly neutralizing antibodies with greater specificity than the canonical mutation D368R, useful in rapidly assessing the nature of a vaccine response. PMID:23159556

  1. Costimulatory Effects of an Immunodominant Parasite Antigen Paradoxically Prevent Induction of Optimal CD8 T Cell Protective Immunity

    PubMed Central

    Vasconcelos, Jose R.; Motz, R. Geoffrey; Sullivan, Nicole L.; Gohara, David W.; Blase, Jennifer R.; Di Cera, Enrico; Hoft, Daniel F.

    2016-01-01

    Trypanosoma cruzi infection is controlled but not eliminated by host immunity. The T. cruzi trans-sialidase (TS) gene superfamily encodes immunodominant protective antigens, but expression of altered peptide ligands by different TS genes has been hypothesized to promote immunoevasion. We molecularly defined TS epitopes to determine their importance for protection versus parasite persistence. Peptide-pulsed dendritic cell vaccination experiments demonstrated that one pair of immunodominant CD4+ and CD8+ TS peptides alone can induce protective immunity (100% survival post-lethal parasite challenge). TS DNA vaccines have been shown by us (and others) to protect BALB/c mice against T. cruzi challenge. We generated a new TS vaccine in which the immunodominant TS CD8+ epitope MHC anchoring positions were mutated, rendering the mutant TS vaccine incapable of inducing immunity to the immunodominant CD8 epitope. Immunization of mice with wild type (WT) and mutant TS vaccines demonstrated that vaccines encoding enzymatically active protein and the immunodominant CD8+ T cell epitope enhance subdominant pathogen-specific CD8+ T cell responses. More specifically, CD8+ T cells from WT TS DNA vaccinated mice were responsive to 14 predicted CD8+ TS epitopes, while T cells from mutant TS DNA vaccinated mice were responsive to just one of these 14 predicted TS epitopes. Molecular and structural biology studies revealed that this novel costimulatory mechanism involves CD45 signaling triggered by enzymatically active TS. This enhancing effect on subdominant T cells negatively regulates protective immunity. Using peptide-pulsed DC vaccination experiments, we have shown that vaccines inducing both immunodominant and subdominant epitope responses were significantly less protective than vaccines inducing only immunodominant-specific responses. These results have important implications for T. cruzi vaccine development. Of broader significance, we demonstrate that increasing breadth of T

  2. Long-Term Immunity to Trypanosoma cruzi in the Absence of Immunodominant trans-Sialidase-Specific CD8+ T Cells

    PubMed Central

    Rosenberg, Charles S.; Zhang, Weibo; Bustamante, Juan M.

    2016-01-01

    Trypanosoma cruzi infection drives the expansion of remarkably focused CD8+ T cell responses targeting epitopes encoded by variant trans-sialidase (TS) genes. Infection of C57BL/6 mice with T. cruzi results in up to 40% of all CD8+ T cells committed to recognition of the dominant TSKB20 and subdominant TSKB18 TS epitopes. However, despite this enormous response, these mice fail to clear T. cruzi infection and subsequently develop chronic disease. One possible reason for the failure to cure T. cruzi infection is that immunodomination by these TS-specific T cells may interfere with alternative CD8+ T cell responses more capable of complete parasite elimination. To address this possibility, we created transgenic mice that are centrally tolerant to these immunodominant epitopes. Mice expressing TSKB20, TSKB18, or both epitopes controlled T. cruzi infection and developed effector CD8+ T cells that maintained an activated phenotype. Memory CD8+ T cells from drug-cured TSKB-transgenic mice rapidly responded to secondary T. cruzi infection. In the absence of the response to TSKB20 and TSKB18, immunodominance did not shift to other known subdominant epitopes despite the capacity of these mice to expand epitope-specific T cells specific for the model antigen ovalbumin expressed by engineered parasites. Thus, CD8+ T cell responses tightly and robustly focused on a few epitopes within variant TS antigens appear to neither contribute to, nor detract from, the ability to control T. cruzi infection. These data also indicate that the relative position of an epitope within a CD8+ immunodominance hierarchy does not predict its importance in pathogen control. PMID:27354447

  3. High-dimensional immunomonitoring models of HIV-1–specific CD8 T-cell responses accurately identify subjects achieving spontaneous viral control

    PubMed Central

    Ndhlovu, Zaza M.; Chibnik, Lori B.; Proudfoot, Jacqueline; Vine, Seanna; McMullen, Ashley; Cesa, Kevin; Porichis, Filippos; Jones, R. Brad; Alvino, Donna Marie; Hart, Meghan G.; Stampouloglou, Eleni; Piechocka-Trocha, Alicja; Kadie, Carl; Pereyra, Florencia; Heckerman, David; De Jager, Philip L.; Walker, Bruce D.

    2013-01-01

    The development of immunomonitoring models to determine HIV-1 vaccine efficacy is a major challenge. Studies suggest that HIV-1–specific CD8 T cells play a critical role in subjects achieving spontaneous viral control (HIV-1 controllers) and that they will be important in immune interventions. However, no single CD8 T-cell function is uniquely associated with controller status and the heterogeneity of responses targeting different epitopes further complicates the discovery of determinants of protective immunity. In the present study, we describe immunomonitoring models integrating multiple functions of epitope-specific CD8 T cells that distinguish controllers from subjects with treated or untreated progressive infection. Models integrating higher numbers of variables and trained with the least absolute shrinkage and selection operator (LASSO) variant of logistic regression and 10-fold cross-validation produce “diagnostic tests” that display an excellent capacity to delineate subject categories. The test accuracy reaches 75% area under the receiving operating characteristic curve in cohorts matched for prevalence of protective alleles. Linear mixed-effects model analyses show that the proliferative capacity, cytokine production, and kinetics of cytokine secretion are associated with HIV-1 control. Although proliferative capacity is the strongest single discriminant, integrated modeling of different dimensions of data leverages individual associations. This strategy may have important applications in predictive model development and immune monitoring of HIV-1 vaccine trials. PMID:23233659

  4. A protective role for dengue virus-specific CD8+ T cells.

    PubMed

    Yauch, Lauren E; Zellweger, Raphaël M; Kotturi, Maya F; Qutubuddin, Afrina; Sidney, John; Peters, Bjoern; Prestwood, Tyler R; Sette, Alessandro; Shresta, Sujan

    2009-04-15

    Infection with one of the four serotypes of dengue virus (DENV1-4) can result in a range of clinical manifestations in humans, from dengue fever to the more serious dengue hemorrhagic fever/dengue shock syndrome. Although T cells have been implicated in the immunopathogenesis of secondary infections with heterologous DENV serotypes, the role of T cells in protection against DENV is unknown. In this study, we used a mouse-passaged DENV2 strain, S221, to investigate the role of CD8(+) T cells in the immune response to primary DENV infection. S221 did not replicate well in wild-type mice, but did induce a CD8(+) T cell response, whereas viral replication and a robust CD8(+) T cell response were observed after infection of IFN-alpha/betaR(-/-) mice. Depletion of CD8(+) T cells from IFN-alpha/betaR(-/-) mice before infection resulted in significantly higher viral loads compared with undepleted mice. Mapping the specificity of the CD8(+) T cell response led to the identification of 12 epitopes derived from 6 of the 10 DENV proteins, with a similar immunodominance hierarchy observed in wild-type and IFN-alpha/betaR(-/-) mice. DENV-specific CD8(+) T cells produced IFN-gamma, TNF-alpha, expressed cell surface CD107a, and exhibited cytotoxic activity in vivo. Finally, immunization with four of the immunodominant CD8(+) T cell epitopes enhanced viral clearance. Collectively, our results reveal an important role for CD8(+) T cells in the host defense against DENV and demonstrate that the anti-DENV CD8(+) T cell response can be enhanced by immunization, providing rationale for designing DENV-specific vaccines that induce cell-mediated immunity.

  5. Identification of atherosclerosis-associated conformational heat shock protein 60 epitopes by phage display and structural alignment.

    PubMed

    Perschinka, Hannes; Wellenzohn, Bernd; Parson, Walther; van der Zee, Ruurd; Willeit, Johann; Kiechl, Stefan; Wick, Georg

    2007-09-01

    Autoimmune reactions to HSP60 are believed to play a key role during development of early atherosclerosis. Due to the high degree of phylogenetic conservation between microbial and human HSP60, bacterial infections might be responsible for inducing cross-reactivity to self HSP60, which is expressed on the surface of arterial endothelial cells stressed by classical atherosclerosis risk factors. Conformational epitopes recognized by polyclonal anti-mycobacterial HSP60 antibodies from subjects with atherosclerosis were identified using a phage displayed random library of cyclic constrained 7mer peptides. After five rounds of selection, DNA sequencing of strongly binding clones revealed that one peptide motif (CIGSPSTNC) was present in 64% of all clones, and a second motif (CSFHYQNRC) in 14%. Using a newly developed method for structural alignment of small constrained peptides onto a protein surface, we located the motif present in 14% of all clones on the surface of mycobacterial HSP60. The motif present in 64% of all clones was found on the surface of mycobacterial HSP60 as well as in the homologous region of human HSP60, which makes this epitope a promising candidate for further investigations on cross-reactive epitopes involved in early atherogenesis.

  6. Expanded CD8 T-cell sharing between periphery and CNS in multiple sclerosis

    PubMed Central

    Salou, Marion; Garcia, Alexandra; Michel, Laure; Gainche-Salmon, Anne; Loussouarn, Delphine; Nicol, Bryan; Guillot, Flora; Hulin, Philippe; Nedellec, Steven; Baron, Daniel; Ramstein, Gérard; Soulillou, Jean-Paul; Brouard, Sophie; Nicot, Arnaud B; Degauque, Nicolas; Laplaud, David A

    2015-01-01

    Objective In multiple sclerosis (MS), central nervous system (CNS), cerebrospinal fluid (CSF), and blood display TCR clonal expansions of CD8+ T cells. These clones have been assumed – but never demonstrated – to be similar in the three compartments. Addressing this key question is essential to infer the implication of peripheral clonally expanded CD8+ T cells in the disease. Methods For the first time, TCR Vβ repertoire from paired blood (purified CD8+ and CD4+ T cells), CSF and CNS (22 lesions, various inflammatory and demyelination statuses) samples from three MS patients was studied using complementary determining region 3 (CDR3) spectratyping and high-throughput sequencing. In parallel, blood and CNS clonally expanded CD8+ T cells were characterized by fluorescent staining. Results TCR Vβ repertoire analysis revealed strong sharing of predominant T-cell clones between CNS lesions, CSF, and blood CD8+ T cells. In parallel, we showed that blood oligoclonal CD8+ T cells exhibit characteristics of pathogenic cells, as they displayed a bias toward a memory phenotype in MS patients, with increased expression of CCR5, CD11a and Granzyme B (GZM-B) compared to non oligoclonal counterparts. CNS-infiltrating T cells were mainly CD8 expressing CD11a and GZM-B. Interpretation This study highlights the predominant implication of CD8+ T cells in MS pathophysiology and demonstrates that potentially aggressive CD8+ T cells can be easily identified and characterized from blood and CSF samples. PMID:26125037

  7. Description of an elasmobranch TCR coreceptor: CD8α from Rhinobatos productus

    USGS Publications Warehouse

    Hansen, J.D.; Farrugia, T.J.; Woodson, J.; Laing, K.J.

    2011-01-01

    Cell-mediated immunity plays an essential role for the control and eradication of intracellular pathogens. To learn more about the evolutionary origins of the first signal (Signal 1) for T-cell activation, we cloned CD8α from an elasmobranch, Rhinobatos productus. Similar to full-length CD8α cDNAs from other vertebrates, Rhpr-CD8α (1800 bp) encodes a 219 amino acid open reading frame composed of a signal peptide, an extracellular IgSF V domain and a stalk/hinge region followed by a well-conserved transmembrane domain and cytoplasmic tail. Overall, the mature Rhpr-CD8α protein (201 aa) displays ~30% amino acid identity with mammalian CD8α including absolute conservation of cysteine residues involved in the IgSf V domain fold and dimerization of CD8αα and CD8αβ. One prominent feature is the absence of the LCK association motif (CXC) that is needed for achieving signal 1 in tetrapods. Both elasmobranch and teleost CD8α protein sequences possess a similar but distinctly different motif (CXH) in the cytoplasmic tail. The overall genomic structure of CD8α has been conserved during the course of vertebrate evolution both for the number of exons and phase of splicing. Finally, quantitative RTPCR demonstrated that elasmobranch CD8α is expressed in lymphoid-rich tissues similar to CD8 in other vertebrates. The results from this study indicate the existence of CD8 prior to the emergence of the gnathostomes (>450 MYA) while providing evidence that the canonical LCK association motif in mammals is likely a derived characteristic of tetrapod CD8α, suggesting potential differences for T-cell education and activation in the various gnathostomes.

  8. Multi-scale modeling of the CD8 immune response

    NASA Astrophysics Data System (ADS)

    Barbarroux, Loic; Michel, Philippe; Adimy, Mostafa; Crauste, Fabien

    2016-06-01

    During the primary CD8 T-Cell immune response to an intracellular pathogen, CD8 T-Cells undergo exponential proliferation and continuous differentiation, acquiring cytotoxic capabilities to address the infection and memorize the corresponding antigen. After cleaning the organism, the only CD8 T-Cells left are antigen-specific memory cells whose role is to respond stronger and faster in case they are presented this very same antigen again. That is how vaccines work: a small quantity of a weakened pathogen is introduced in the organism to trigger the primary response, generating corresponding memory cells in the process, giving the organism a way to defend himself in case it encounters the same pathogen again. To investigate this process, we propose a non linear, multi-scale mathematical model of the CD8 T-Cells immune response due to vaccination using a maturity structured partial differential equation. At the intracellular scale, the level of expression of key proteins is modeled by a delay differential equation system, which gives the speeds of maturation for each cell. The population of cells is modeled by a maturity structured equation whose speeds are given by the intracellular model. We focus here on building the model, as well as its asymptotic study. Finally, we display numerical simulations showing the model can reproduce the biological dynamics of the cell population for both the primary response and the secondary responses.

  9. Phenotypic and functional characteristics of IL-21-expressing CD8+ T cells in human nasal polyps

    PubMed Central

    Xiao, Li; Jia, Lei; Bai, Lu; He, Long; Yang, Binyan; Wu, Changyou; Li, Huabin

    2016-01-01

    Although CD4+ T cells are recognized to play an important role in the inflammatory response of nasal polyps (NPs), the biological functions of CD8+ T cells in polypogenesis remain unclear. In this study, we analyzed cell markers, cytokine expression and transcription factors in IL-21-expressing CD8+ T cells in polyp tissues of NP patients. The results showed that the majority of IL-21-producing CD8+ T cells were effector memory cells and they co-expressed IFN-γ. IL-21-expressing CD8+ T cells in polyp tissues expressed higher CXCR5, PD-1, and ICOS levels than cells in control tissues and showed significantly higher T-bet and Bcl-6 expression levels compared with IL-21−CD8+ T cells. Purified polyp CD8+ T cells promoted IgG production from isolated polyp B cells in vitro, and recombinant IL-12 modulated the expression of IL-21, IFN-γ and CD40L in purified polyp CD8+ T cells. Moreover, the percentage of IL-21+CD8+ T cells in polyp tissues was positively correlated with endoscopic and CT scan scores in NP patients. These findings indicated that polyp CD8+ T cells, by co-expressing IL-21 and IFN-γ and other markers, display a Tfh cell functionality, which is associated with the clinical severity of NP patients. PMID:27468819

  10. Salmonella enteritidis fimbriae displaying a heterologous epitope reveal a uniquely flexible structure and assembly mechanism.

    PubMed

    White, A P; Collinson, S K; Banser, P A; Dolhaine, D J; Kay, W W

    2000-02-18

    Two distinct Salmonella fimbrins, AgfA and SefA, comprising thin aggregative fimbriae SEF17 and SEF14, respectively, were each genetically engineered to carry PT3, an alpha-helical 16-amino acid Leishmania T-cell epitope derived from the metalloprotease gp63. To identify regions within AgfA and SefA fimbrins amenable to replacement with this epitope, PCR-generated chimeric fimbrin genes were constructed and used to replace the native chromosomal agfA and sefA genes in Salmonella enteritidis. Immunoblot analysis using anti-SEF17 and anti-PT3 sera demonstrated that all ten AgfA chimeric fimbrin proteins were expressed by S. enteritidis under normal growth conditions. Immunoelectron microscopy confirmed that eight of the AgfA::PT3 proteins were effectively assembled into cell surface-exposed fimbriae. The PT3 replacements in AgfA altered Congo red (CR) binding, cell-cell adhesion and cell surface properties of S. enteritidis to varying degrees. However, these chimeric fimbriae were still highly stable, being resistant to proteinase K digestion and requiring harsh formic acid treatment for depolymerization. In marked contrast to AgfA, none of the chimeric SefA proteins were expressed or assembled into fimbriae. Since each PT3 replacement constituted over 10% of the AgfA amino acid sequence and all ten replacements collectively represented greater than 75% of the entire AgfA primary sequence, the ability of AgfA to accept large sequence substitutions and still assemble into fibers is unique among fimbriae and other structural proteins. This structural flexibility may be related to the novel fivefold repeating sequence of AgfA and its recently proposed structure Proper formation of chimeric fimbrial fibers suggests an unusual assembly mechanism for thin aggregative fimbriae which tolerates aberrant structures. This study opens a range of possibilities for Salmonella thin aggregative fimbriae as a carrier of heterologous epitopes and as an experimental model for studies

  11. Comparison of influenza and SIV specific CD8 T cell responses in macaques.

    PubMed

    Jegaskanda, Sinthujan; Reece, Jeanette C; De Rose, Robert; Stambas, John; Sullivan, Lucy; Brooks, Andrew G; Kent, Stephen J; Sexton, Amy

    2012-01-01

    Macaques are a potentially useful non-human primate model to compare memory T-cell immunity to acute virus pathogens such as influenza virus and effector T-cell responses to chronic viral pathogens such as SIV. However, immunological reagents to study influenza CD8(+) T-cell responses in the macaque model are limited. We recently developed an influenza-SIV vaccination model of pigtail macaques (Macaca nemestrina) and used this to study both influenza-specific and SIV-specific CD8(+) T-cells in 39 pigtail macaques expressing the common Mane-A*10(+) (Mane-A01*084) MHC-I allele. To perform comparative studies between influenza and SIV responses a common influenza nucleoprotein-specific CD8(+) T-cell response was mapped to a minimal epitope (termed RA9), MHC-restricted to Mane-A*10 and an MHC tetramer developed to study this response. Influenza-specific memory CD8(+) T-cell response maintained a highly functional profile in terms of multitude of effector molecule expression (CD107a, IFN-γ, TNF-α, MIP-1β and IL-2) and showed high avidity even in the setting of SIV infection. In contrast, within weeks following active SIV infection, SIV-specific CD8(+) effector T-cells expressed fewer cytokines/degranulation markers and had a lower avidity compared to influenza specific CD8(+) T-cells. Further, the influenza specific memory CD8 T-cell response retained stable expression of the exhaustion marker programmed death-marker-1 (PD-1) and co-stimulatory molecule CD28 following infection with SIV. This contrasted with the effector SIV-specific CD8(+) T-cells following SIV infection which expressed significantly higher amounts of PD-1 and lower amounts of CD28. Our results suggest that strategies to maintain a more functional CD8(+) T-cell response, profile may assist in controlling HIV disease.

  12. Extensive CD4 and CD8 T-cell cross-reactivity between alphaherpesviruses1

    PubMed Central

    Dong, Lichun; Russell, Ronnie M.; Barlow, Russell S.; Haas, Juergen G.; Ramchandani, Meena S.; Johnston, Christine; Buus, Soren; Redwood, Alec J.; White, Katie D.; Mallal, Simon A.; Phillips, Elizabeth J.; Posavad, Christine M.; Wald, Anna; Koelle, David M.

    2015-01-01

    The alphaherpesvirinae subfamily includes HSV types 1 and 2 and the sequence-divergent pathogen varicella zoster virus (VZV). T cells, controlled by TCR and HLA molecules that tolerate limited epitope amino acid variation, might cross-react between these microbes. We show that memory PBMC expansion with either HSV or VZV enriches for CD4 T cell lines that recognize the other agent at the whole virus, protein, and peptide levels, consistent with bi-directional cross-reactivity. HSV-specific CD4 T cells recovered from HSV seronegative persons can be partially explained by such VZV cross-reactivity. HSV-1-reactive CD8 T cells also cross-react with VZV-infected cells, full-length VZV proteins, and VZV peptides, and kill VZV-infected dermal fibroblasts. Mono- and cross-reactive CD8 T cells use distinct TCRB CDR3 sequences. Cross-reactivity to VZV is reconstituted by cloning and expressing TCRA/TCRB receptors from T-cells that are initially isolated using HSV reagents. Overall, we define 13 novel CD4 and CD8 HSV-VZV cross-reactive epitopes and strongly imply additional cross-reactive peptide sets. Viral proteins can harbor both CD4 and CD8 HSV/VZV cross-reactive epitopes. Quantitative estimates of HSV/VZV cross-reactivity for both CD4 and CD8 T cells vary from 10-50%. Based on these findings, we hypothesize host herpesvirus immune history may influence the pathogenesis and clinical outcome of subsequent infections or vaccinations for related pathogens, and that cross-reactive epitopes and TCRs may be useful for multi-alphaherpesvirus vaccine design and adoptive cellular therapy. PMID:26810224

  13. A Conserved Epitope Mapped with a Monoclonal Antibody against the VP3 Protein of Goose Parvovirus by Using Peptide Screening and Phage Display Approaches

    PubMed Central

    Li, Chenxi; Liu, Hongyu; Li, Jinzhe; Liu, Dafei; Meng, Runze; Zhang, Qingshan; Shaozhou, Wulin; Bai, Xiaofei; Zhang, Tingting; Liu, Ming; Zhang, Yun

    2016-01-01

    Background Waterfowl parvovirus (WPV) infection causes high mortality and morbidity in both geese (Anser anser) and Muscovy ducks (Cairina moschata), resulting in significant losses to the waterfowl industries. The VP3 protein of WPV is a major structural protein that induces neutralizing antibodies in the waterfowl. However, B-cell epitopes on the VP3 protein of WPV have not been characterized. Methods and Results To understand the antigenic determinants of the VP3 protein, we used the monoclonal antibody (mAb) 4A6 to screen a set of eight partially expressed overlapping peptides spanning VP3. Using western blotting and an enzyme-linked immunosorbent assay (ELISA), we localized the VP3 epitope between amino acids (aa) 57 and 112. To identify the essential epitope residues, a phage library displaying 12-mer random peptides was screened with mAb 4A6. Phage clone peptides displayed a consensus sequence of YxRFHxH that mimicked the sequence 82Y/FNRFHCH88, which corresponded to amino acid residues 82 to 88 of VP3 protein of WPVs. mAb 4A6 binding to biotinylated fragments corresponding to amino acid residues 82 to 88 of the VP3 protein verified that the 82FxRFHxH88 was the VP3 epitope and that amino acids 82F is necessary to retain maximal binding to mAb 4A6. Parvovirus-positive goose and duck sera reacted with the epitope peptide by dot blotting assay, revealing the importance of these amino acids of the epitope in antibody-epitope binding reactivity. Conclusions and Significance We identified the motif FxRFHxH as a VP3-specific B-cell epitope that is recognized by the neutralizing mAb 4A6. This finding might be valuable in understanding of the antigenic topology of VP3 of WPV. PMID:27191594

  14. Channel catfish CD8a and CD8ß co-receptors characterization expression and polymorphism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study we report the identification and characterization of channel catfish, Ictalurus punctatus CD8a and CD8ß genes. Both genes encode predicted proteins containing a leader, a immunoglobulin superfamily V domain, a stalk/hinge region, a transmembrane region and a positively charged cytoplas...

  15. Induction of a Cross-Reactive CD8+ T Cell Response following Foot-and-Mouth Disease Virus Vaccination▿

    PubMed Central

    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 cell epitopes in FMDV recognized by cattle vaccinated with inactivated FMDV serotype O. Analysis of gamma interferon (IFN-γ)-producing CD8+ T cells responding to stimulation with FMDV-derived peptides revealed one putative CD8+ T cell epitope present within the structural protein P1D, comprising residues 795 to 803 of FMDV serotype O UKG/2001. The restricting major histocompatibility complex (MHC) class I allele was N*02201, expressed by the A31 haplotype. This epitope induced IFN-γ release, proliferation, and target cell killing by αβ CD8+ T cells, but not CD4+ T cells. A protein alignment of representative samples from each of the 7 FMDV serotypes showed that the putative epitope is highly conserved. CD8+ T cells from FMDV serotype O-vaccinated A31+ cattle recognized antigen-presenting cells (APCs) loaded with peptides derived from all 7 FMDV serotypes, suggesting that CD8+ T cells recognizing the defined epitope are cross-reactive to equivalent peptides derived from all of the other FMDV serotypes. PMID:20861264

  16. Display of the Viral Epitopes on Lactococcus lactis: A Model for Food Grade Vaccine against EV71.

    PubMed

    Varma, Nadimpalli Ravi S; Toosa, Haryanti; Foo, Hooi Ling; Alitheen, Noorjahan Banu Mohamed; Nor Shamsudin, Mariana; Arbab, Ali S; Yusoff, Khatijah; Abdul Rahim, Raha

    2013-01-01

    In this study, we have developed a system for display of antigens of Enterovirus type 71 (EV71) on the cell surface of L. lactis. The viral capsid protein (VP1) gene from a local viral isolate was utilized as the candidate vaccine for the development of oral live vaccines against EV71 using L. lactis as a carrier. We expressed fusion proteins in E. coli and purified fusion proteins were incubated with L. lactis. We confirmed that mice orally fed with L. lactis displaying these fusion proteins on its surface were able to mount an immune response against the epitopes of EV71. This is the first example of an EV71 antigen displayed on the surface of a food grade organism and opens a new perspective for alternative vaccine strategies against the EV71. We believe that the method of protein docking utilized in this study will allow for more flexible presentations of short peptides and proteins on the surface of L. lactis to be useful as a delivery vehicle.

  17. Display of the Viral Epitopes on Lactococcus lactis: A Model for Food Grade Vaccine against EV71

    PubMed Central

    Varma, Nadimpalli Ravi S.; Toosa, Haryanti; Foo, Hooi Ling; Alitheen, Noorjahan Banu Mohamed; Nor Shamsudin, Mariana; Arbab, Ali S.; Yusoff, Khatijah; Abdul Rahim, Raha

    2013-01-01

    In this study, we have developed a system for display of antigens of Enterovirus type 71 (EV71) on the cell surface of L. lactis. The viral capsid protein (VP1) gene from a local viral isolate was utilized as the candidate vaccine for the development of oral live vaccines against EV71 using L. lactis as a carrier. We expressed fusion proteins in E. coli and purified fusion proteins were incubated with L. lactis. We confirmed that mice orally fed with L. lactis displaying these fusion proteins on its surface were able to mount an immune response against the epitopes of EV71. This is the first example of an EV71 antigen displayed on the surface of a food grade organism and opens a new perspective for alternative vaccine strategies against the EV71. We believe that the method of protein docking utilized in this study will allow for more flexible presentations of short peptides and proteins on the surface of L. lactis to be useful as a delivery vehicle. PMID:23476790

  18. Epitope mapping and key amino acid identification of anti-CD22 immunotoxin CAT-8015 using hybrid β-lactamase display

    PubMed Central

    Bannister, D.; Popovic, B.; Sridharan, S.; Giannotta, F.; Filée, P.; Yilmaz, N.; Minter, R.

    2011-01-01

    Monoclonal antibodies are a commercially successful class of drug molecules and there are now a growing number of antibodies coupled to toxic payloads, which demonstrate clinical efficacy. Determining the precise epitope of therapeutic antibodies is beneficial in understanding the structure–activity relationship of the drug, but in many cases is not done due to the structural complexity of, in particular, conformational protein epitopes. Using the immunotoxin CAT-8015 as a test case, this study demonstrates that a new methodology, hybrid β-lactamase display, can be employed to elucidate a complex epitope on CD22. Following insertion of random CD22 gene fragments into a permissive site within β-lactamase, proteins expressed in Escherichia coli were first screened for correct folding by resistance to ampicillin and then selected by phage display for affinity to CAT-8015. The optimal protein region recognised by CAT-8015 could then be used as a tool for fine epitope mapping, using alanine-scanning analysis, demonstrating that this technology is well suited to the rapid characterisation of antibody epitopes. PMID:21159620

  19. Epitope mapping and key amino acid identification of anti-CD22 immunotoxin CAT-8015 using hybrid β-lactamase display.

    PubMed

    Bannister, D; Popovic, B; Sridharan, S; Giannotta, F; Filée, P; Yilmaz, N; Minter, R

    2011-04-01

    Monoclonal antibodies are a commercially successful class of drug molecules and there are now a growing number of antibodies coupled to toxic payloads, which demonstrate clinical efficacy. Determining the precise epitope of therapeutic antibodies is beneficial in understanding the structure-activity relationship of the drug, but in many cases is not done due to the structural complexity of, in particular, conformational protein epitopes. Using the immunotoxin CAT-8015 as a test case, this study demonstrates that a new methodology, hybrid β-lactamase display, can be employed to elucidate a complex epitope on CD22. Following insertion of random CD22 gene fragments into a permissive site within β-lactamase, proteins expressed in Escherichia coli were first screened for correct folding by resistance to ampicillin and then selected by phage display for affinity to CAT-8015. The optimal protein region recognised by CAT-8015 could then be used as a tool for fine epitope mapping, using alanine-scanning analysis, demonstrating that this technology is well suited to the rapid characterisation of antibody epitopes.

  20. Measuring the diaspora for virus-specific CD8+ T cells.

    PubMed

    Marshall, D R; Turner, S J; Belz, G T; Wingo, S; Andreansky, S; Sangster, M Y; Riberdy, J M; Liu, T; Tan, M; Doherty, P C

    2001-05-22

    The CD8(+) T cell diaspora has been analyzed after secondary challenge with an influenza A virus that replicates only in the respiratory tract. Numbers of D(b)NP(366)- and D(b)PA(224)-specific CD8(+) T cells were measured by tetramer staining at the end of the recall response, then followed sequentially in the lung, lymph nodes, spleen, blood, and other organs. The extent of clonal expansion did not reflect the sizes of the preexisting memory T cell pools. Although the high-frequency CD8(+) tetramer(+) populations in the pneumonic lung and mediastinal lymph nodes fell rapidly from peak values, the "whole mouse" virus-specific CD8(+) T cell counts decreased only 2-fold over the 4 weeks after infection, then subsided at a fairly steady rate to reach a plateau at about 2 months. The largest numbers were found throughout in the spleen, then the bone marrow. The CD8(+)D(b)NP(366)+ and CD8(+)D(b)PA(224)+ sets remained significantly enlarged for at least 4 months, declining at equivalent rates while retaining the nucleoprotein > acid polymerase immunodominance hierarchy characteristic of the earlier antigen-driven phase. Lowest levels of the CD69 "activation marker" were detected consistently on virus-specific CD8(+) T cells in the blood, then the spleen. Those in the bone marrow and liver were intermediate, and CD69(hi) T cells were very prominent in the regional lymph nodes and the nasal-associated lymphoid tissue. Any population of "resting" CD8(+) memory T cells is thus phenotypically heterogeneous, widely dispersed, and subject to broad homeostatic and local environmental effects irrespective of epitope specificity or magnitude.

  1. CD8 T-cell recognition of acquired alloantigen promotes acute allograft rejection

    PubMed Central

    Harper, Simon J. F.; Ali, Jason M.; Wlodek, Elizabeth; Negus, Marg C.; Harper, Ines G.; Chhabra, Manu; Qureshi, M. Saeed; Mallik, Mekhola; Bolton, Eleanor; Bradley, J. Andrew; Pettigrew, Gavin J.

    2015-01-01

    Adaptive CD8 T-cell immunity is the principal arm of the cellular alloimmune response, but its development requires help. This can be provided by CD4 T cells that recognize alloantigen “indirectly,” as self-restricted allopeptide, but this process remains unexplained, because the target epitopes for CD4 and CD8 T-cell recognition are “unlinked” on different cells (recipient and donor antigen presenting cells (APCs), respectively). Here, we test the hypothesis that the presentation of intact and processed MHC class I alloantigen by recipient dendritic cells (DCs) (the “semidirect” pathway) allows linked help to be delivered by indirect-pathway CD4 T cells for generating destructive cytotoxic CD8 T-cell alloresponses. We show that CD8 T-cell–mediated rejection of murine heart allografts that lack hematopoietic APCs requires host secondary lymphoid tissue (SLT). SLT is necessary because within it, recipient dendritic cells can acquire MHC from graft parenchymal cells and simultaneously present it as intact protein to alloreactive CD8 T cells and as processed peptide alloantigen for recognition by indirect-pathway CD4 T cells. This enables delivery of essential help for generating cytotoxic CD8 T-cell responses that cause rapid allograft rejection. In demonstrating the functional relevance of the semidirect pathway to transplant rejection, our findings provide a solution to a long-standing conundrum as to why SLT is required for CD8 T-cell allorecognition of graft parenchymal cells and suggest a mechanism by which indirect-pathway CD4 T cells provide help for generating effector cytotoxic CD8 T-cell alloresponses at late time points after transplantation. PMID:26420874

  2. Identification of two linear B-cell epitopes from West Nile virus NS1 by screening a phage-displayed random peptide library

    PubMed Central

    2011-01-01

    Background The West Nile virus (WNV) nonstructural protein 1 (NS1) is an important antigenic protein that elicits protective antibody responses in animals and can be used for the serological diagnosis of WNV infection. Although previous work has demonstrated the vital role of WNV NS1-specific antibody responses, the specific epitopes in the NS1 have not been identified. Results The present study describes the identification of two linear B-cell epitopes in WNV NS1 through screening a phage-displayed random 12-mer peptide library with two monoclonal antibodies (mAbs) 3C7 and 4D1 that directed against the NS1. The mAbs 3C7 and 4D1 recognized phages displaying peptides with the consensus motifs LTATTEK and VVDGPETKEC, respectively. Exact sequences of both motifs were found in the NS1 (895LTATTEK901 and 925VVDGPETKEC934). Further identification of the displayed B cell epitopes were conducted using a set of truncated peptides expressed as MBP fusion proteins. The data indicated that 896TATTEK901 and925VVDGPETKEC934 are minimal determinants of the linear B cell epitopes recognized by the mAbs 3C7 and 4D1, respectively. Antibodies present in the serum of WNV-positive horses recognized the minimal linear epitopes in Western blot analysis, indicating that the two peptides are antigenic in horses during infection. Furthermore, we found that the epitope recognized by 3C7 is conserved only among WNV strains, whereas the epitope recognized by 4D1 is a common motif shared among WNV and other members of Japanese encephalitis virus (JEV) serocomplex. Conclusions We identified TATTEK and VVDGPETKEC as NS1-specific linear B-cell epitopes recognized by the mAbs 3C7 and 4D1, respectively. The knowledge and reagents generated in this study may have potential applications in differential diagnosis and the development of epitope-based marker vaccines against WNV and other viruses of JEV serocomplex. PMID:21729328

  3. Complementary Dendritic Cell–activating Function of CD8+ and CD4+ T Cells

    PubMed Central

    Mailliard, Robbie B.; Egawa, Shinichi; Cai, Quan; Kalinska, Anna; Bykovskaya, Svetlana N.; Lotze, Michael T.; Kapsenberg, Martien L.; Storkus, Walter J.; Kalinski, Pawel

    2002-01-01

    Dendritic cells (DCs) activated by CD40L-expressing CD4+ T cells act as mediators of “T helper (Th)” signals for CD8+ T lymphocytes, inducing their cytotoxic function and supporting their long-term activity. Here, we show that the optimal activation of DCs, their ability to produce high levels of bioactive interleukin (IL)-12p70 and to induce Th1-type CD4+ T cells, is supported by the complementary DC-activating signals from both CD4+ and CD8+ T cells. Cord blood– or peripheral blood–isolated naive CD8+ T cells do not express CD40L, but, in contrast to naive CD4+ T cells, they are efficient producers of IFN-γ at the earliest stages of the interaction with DCs. Naive CD8+ T cells cooperate with CD40L-expressing naive CD4+ T cells in the induction of IL-12p70 in DCs, promoting the development of primary Th1-type CD4+ T cell responses. Moreover, the recognition of major histocompatibility complex class I–presented epitopes by antigen-specific CD8+ T cells results in the TNF-α– and IFN-γ–dependent increase in the activation level of DCs and in the induction of type-1 polarized mature DCs capable of producing high levels of IL-12p70 upon a subsequent CD40 ligation. The ability of class I–restricted CD8+ T cells to coactivate and polarize DCs may support the induction of Th1-type responses against class I–presented epitopes of intracellular pathogens and contact allergens, and may have therapeutical implications in cancer and chronic infections. PMID:11854360

  4. Modulating DNA methylation in activated CD8+ T cells inhibits regulatory T cell-induced binding of Foxp3 to the CD8+ T Cell IL-2 promoter.

    PubMed

    Miller, Michelle M; Akaronu, Nnenna; Thompson, Elizabeth M; Hood, Sylvia F; Fogle, Jonathan E

    2015-02-01

    We have previously demonstrated that CD4(+)CD25(+) regulatory T cells (Tregs) activated during the course of feline immunodeficiency virus (FIV) infection suppress CD8(+) CTL function in a TGF-β-dependent fashion, inhibiting IFN-γ and IL-2 production and inducing G1 cell-cycle arrest. In this article, we describe the molecular events occurring at the IL-2 promoter leading to suppression of IL-2 production. These experiments demonstrate that Foxp3 induced by lentivirus-activated Tregs in the CD8(+) target cells binds to the IL-2 promoter, actively repressing IL-2 transcription. We further demonstrate that the chronic activation of CD8(+) T cells during FIV infection results in chromatin remodeling at the IL-2 promoter, specifically, demethylation of CpG residues. These DNA modifications occur during active transcription and translation of IL-2; however, these changes render the IL-2 promoter permissive to Foxp3-induced transcriptional repression. These data help explain, in part, the seemingly paradoxical observations that CD8(+) T cells displaying an activation phenotype exhibit altered antiviral function. Further, we demonstrate that blocking demethylation of CpG residues at the IL-2 promoter inhibits Foxp3 binding, suggesting a potential mechanism for rescue and/or reactivation of CD8(+) T cells. Using the FIV model for lentiviral persistence, these studies provide a framework for understanding how immune activation combined with Treg-mediated suppression may affect CD8(+) T cell IL-2 transcription, maturation, and antiviral function.

  5. Identification of an Immunogenic Mimic of a Conserved Epitope on the Plasmodium falciparum Blood Stage Antigen AMA1 Using Virus-Like Particle (VLP) Peptide Display

    PubMed Central

    Crossey, Erin; Frietze, Kathryn; Narum, David L.; Peabody, David S.; Chackerian, Bryce

    2015-01-01

    We have developed a peptide display platform based on VLPs of the RNA bacteriophage MS2 that combines the high immunogenicity of VLP display with affinity selection capabilities. Random peptides can be displayed on the VLP surface by genetically inserting sequences into a surface-exposed loop of the viral coat protein. VLP-displayed peptides can then be isolated by selection using antibodies, and the VLP selectants can then be used directly as immunogens. Here, we investigated the ability of this platform to identify mimotopes of a highly conserved conformational epitope present on the Plasmodium falciparum blood-stage protein AMA1. Using 4G2, a monoclonal antibody that binds to this epitope and is a potent inhibitor of erythrocyte invasion, we screened three different VLP-peptide libraries and identified specific VLPs that bound strongly to the selecting mAb. We then tested the ability of a handful of selected VLPs to elicit anti-AMA1 antibody responses in mice. Most of the selected VLPs failed to reliably elicit AMA1 specific antibodies. However, one VLP consistently induced antibodies that cross-reacted with AMA1. Surprisingly, this VLP bound to 4G2 more weakly than the other selectants we identified. Taken together, these data demonstrate that VLP-peptide display can identify immunogenic mimics of a complex conformational epitope and illustrate the promise and challenges of this approach. PMID:26147502

  6. B7-H1 Blockade Increases Survival of Dysfunctional CD8+ T Cells and Confers Protection against Leishmania donovani Infections

    PubMed Central

    Joshi, Trupti; Rodriguez, Susana; Perovic, Vladimir; Cockburn, Ian A.; Stäger, Simona

    2009-01-01

    Experimental visceral leishmaniasis (VL) represents an exquisite model to study CD8+ T cell responses in a context of chronic inflammation and antigen persistence, since it is characterized by chronic infection in the spleen and CD8+ T cells are required for the development of protective immunity. However, antigen-specific CD8+ T cell responses in VL have so far not been studied, due to the absence of any defined Leishmania-specific CD8+ T cell epitopes. In this study, transgenic Leishmania donovani parasites expressing ovalbumin were used to characterize the development, function, and fate of Leishmania-specific CD8+ T cell responses. Here we show that L. donovani parasites evade CD8+ T cell responses by limiting their expansion and inducing functional exhaustion and cell death. Dysfunctional CD8+ T cells could be partially rescued by in vivo B7-H1 blockade, which increased CD8+ T cell survival but failed to restore cytokine production. Nevertheless, B7-H1 blockade significantly reduced the splenic parasite burden. These findings could be exploited for the design of new strategies for immunotherapeutic interventions against VL. PMID:19436710

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

    PubMed

    Torti, Nicole; Walton, Senta M; Brocker, Thomas; Rülicke, Thomas; Oxenius, Annette

    2011-10-01

    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.

  8. CD8+ T cells specific for the islet autoantigen IGRP are restricted in their T cell receptor chain usage

    PubMed Central

    Fuchs, Yannick F.; Eugster, Anne; Dietz, Sevina; Sebelefsky, Christian; Kühn, Denise; Wilhelm, Carmen; Lindner, Annett; Gavrisan, Anita; Knoop, Jan; Dahl, Andreas; Ziegler, Anette-G.; Bonifacio, Ezio

    2017-01-01

    CD8+ T cells directed against beta cell autoantigens are considered relevant for the pathogenesis of type 1 diabetes. Using single cell T cell receptor sequencing of CD8+ T cells specific for the IGRP265-273 epitope, we examined whether there was expansion of clonotypes and sharing of T cell receptor chains in autoreactive CD8+ T cell repertoires. HLA-A*0201 positive type 1 diabetes patients (n = 19) and controls (n = 18) were analysed. TCR α- and β-chain sequences of 418 patient-derived IGRP265-273-multimer+ CD8+ T cells representing 48 clonotypes were obtained. Expanded populations of IGRP265-273-specific CD8+ T cells with dominant clonotypes that had TCR α-chains shared across patients were observed. The SGGSNYKLTF motif corresponding to TRAJ53 was contained in 384 (91.9%) cells, and in 20 (41.7%) patient-derived clonotypes. TRAJ53 together with TRAV29/DV5 was found in 15 (31.3%) clonotypes. Using next generation TCR α-chain sequencing, we found enrichment of one of these TCR α-chains in the memory CD8+ T cells of patients as compared to healthy controls. CD8+ T cell clones bearing the enriched motifs mediated antigen-specific target cell lysis. We provide the first evidence for restriction of T cell receptor motifs in the alpha chain of human CD8+ T cells with specificity to a beta cell antigen. PMID:28300170

  9. Dengue virus protein recognition by virus-specific murine CD8+ cytotoxic T lymphocytes.

    PubMed Central

    Rothman, A L; Kurane, I; Lai, C J; Bray, M; Falgout, B; Men, R; Ennis, F A

    1993-01-01

    The identification of the protein targets for dengue virus-specific T lymphocytes may be useful for planning the development of subunit vaccines against dengue. We studied the recognition by murine dengue virus-specific major histocompatibility complex class I-restricted, CD8+ cytotoxic T lymphocytes (CTL) of dengue virus proteins using recombinant vaccinia viruses containing segments of the dengue virus genome. CTL from H-2k mice recognized a single serotype-cross-reactive epitope on the nonstructural (NS) protein NS3. CTL from H-2b mice recognized a serotype-cross-reactive epitope that was localized to NS4a or NS4b. CTL from H-2d mice recognized at least three epitopes: a serotype-specific epitope on one of the structural proteins, a serotype-cross-reactive epitope on NS3, and a serotype-cross-reactive epitope on NS1 or NS2a. Our findings demonstrate the limited recognition of dengue virus proteins by CTL from three inbred mouse strains and the predominance of CTL epitopes on dengue virus nonstructural proteins, particularly NS3. Since human dengue virus-specific CTL show similar patterns of recognition, these findings suggest that nonstructural proteins should be considered in designing vaccines against dengue. PMID:7678307

  10. Understanding the Failure of CD8+ T-Cell Vaccination against Simian/Human Immunodeficiency Virus▿

    PubMed Central

    De Boer, Rob J.

    2007-01-01

    Although CD8+ T cells play an important role in controlling viral infections, boosting specific CD8+ T cells by prophylactic vaccination with simian immunodeficiency virus (SIV) epitopes fails to provide sterilizing immunity. Viral replication rates and viral contraction rates after the peak viremia hardly depend on the presence of memory CD8+ T cells. To study these paradoxical findings, we parameterize novel mathematical models for acute SIV and human immunodeficiency virus infection. These models explain that failure of vaccination is due to the fact that effector/target ratios are too low during the viral expansion phase. Because CD8+ T cells require cell-to-cell contacts, immune protection requires high effector/target ratios at the primary site of infection. Effector/target ratios become favorable for immune control at the time of the peak in the viral load when the virus becomes limited by other factors, such as the availability of uninfected target cells. At the viral set point, effector/target ratios are much higher, and perturbations of the number of CD8+ effector cells have a large impact on the viral load. Such protective effector/target ratios are difficult to achieve with nucleic acid- or protein-based vaccines. PMID:17202215

  11. Altered Function in CD8+ T Cells following Paramyxovirus Infection of the Respiratory Tract

    PubMed Central

    Gray, Peter M.; Arimilli, Subhashini; Palmer, Ellen M.; Parks, Griffith D.; Alexander-Miller, Martha A.

    2005-01-01

    For many respiratory pathogens, CD8+ T cells have been shown to play a critical role in clearance. However, there are still many unanswered questions with regard to the factors that promote the most efficacious immune response and the potential for immunoregulation of effector cells at the local site of infection. We have used infection of the respiratory tract with the model paramyxovirus simian virus 5 (SV5) to study CD8+ T-cell responses in the lung. For the present study, we report that over time a population of nonresponsive, virus-specific CD8+ T cells emerged in the lung, culminating in a lack of function in ∼85% of cells specific for the immunodominant epitope from the viral matrix (M) protein by day 40 postinfection. Concurrent with the induction of nonresponsiveness, virus-specific cells that retained function at later times postinfection exhibited an increased requirement for CD8 engagement. This change was coupled with a nearly complete loss of functional phosphoprotein-specific cells, a response previously shown to be almost exclusively CD8 independent. These studies add to the growing evidence for immune dysregulation following viral infection of the respiratory tract. PMID:15731228

  12. Divide, Conquer, and Sense: CD8+CD28− T Cells in Perspective

    PubMed Central

    Arosa, Fernando A.; Esgalhado, André J.; Padrão, Carolina A.; Cardoso, Elsa M.

    2017-01-01

    Understanding the rationale for the generation of a pool of highly differentiated effector memory CD8+ T cells displaying a weakened capacity to scrutinize for peptides complexed with major histocompatibility class I molecules via their T cell receptor, lacking the “signal 2” CD28 receptor, and yet expressing a highly diverse array of innate receptors, from natural killer receptors, interleukin receptors, and damage-associated molecular pattern receptors, among others, is one of the most challenging issues in contemporary human immunology. The prevalence of these differentiated CD8+ T cells, also known as CD8+CD28−, CD8+KIR+, NK-like CD8+ T cells, or innate CD8+ T cells, in non-lymphoid organs and tissues, in peripheral blood of healthy elderly, namely centenarians, but also in stressful and chronic inflammatory conditions suggests that they are not merely end-of-the-line dysfunctional cells. These experienced CD8+ T cells are highly diverse and capable of sensing a variety of TCR-independent signals, which enables them to respond and fine-tune tissue homeostasis. PMID:28096804

  13. Divide, Conquer, and Sense: CD8(+)CD28(-) T Cells in Perspective.

    PubMed

    Arosa, Fernando A; Esgalhado, André J; Padrão, Carolina A; Cardoso, Elsa M

    2016-01-01

    Understanding the rationale for the generation of a pool of highly differentiated effector memory CD8(+) T cells displaying a weakened capacity to scrutinize for peptides complexed with major histocompatibility class I molecules via their T cell receptor, lacking the "signal 2" CD28 receptor, and yet expressing a highly diverse array of innate receptors, from natural killer receptors, interleukin receptors, and damage-associated molecular pattern receptors, among others, is one of the most challenging issues in contemporary human immunology. The prevalence of these differentiated CD8(+) T cells, also known as CD8(+)CD28(-), CD8(+)KIR(+), NK-like CD8(+) T cells, or innate CD8(+) T cells, in non-lymphoid organs and tissues, in peripheral blood of healthy elderly, namely centenarians, but also in stressful and chronic inflammatory conditions suggests that they are not merely end-of-the-line dysfunctional cells. These experienced CD8(+) T cells are highly diverse and capable of sensing a variety of TCR-independent signals, which enables them to respond and fine-tune tissue homeostasis.

  14. Fine epitope mapping of monoclonal antibodies against hemagglutinin of a highly pathogenic H5N1 influenza virus using yeast surface display

    PubMed Central

    Han, Thomas; Sui, Jianhua; Bennett, Andrew S.; Liddington, Robert C.; Donis, Ruben O.; Zhu, Quan; Marasco, Wayne A.

    2011-01-01

    Highly pathogenic H5N1 avian influenza viruses pose a debilitating pandemic threat. Thus, understanding mechanisms of antibody-mediated viral inhibition and neutralization escape is critical. Here, a robust yeast display system for fine epitope mapping of viral surface hemagglutinin (HA)-specific antibodies is demonstrated. The full-length H5 subtype HA (HA0) was expressed on the yeast surface in a correctly folded conformation, determined by binding of a panel of extensively characterized neutralizing human monoclonal antibodies (mAbs). These mAbs target conformationally-dependent epitopes of influenza A HA, which are highly conserved across H5 clades and group 1 serotypes. By separately displaying HA1 and HA2 subunits on yeast, domain mapping of two anti-H5 mAbs, NR2728 and H5-2A, localized their epitopes to HA1. These anti-H5 mAb epitopes were further fine mapped by using a library of yeast-displayed HA1 mutants and selecting for loss of binding without prior knowledge of potential contact residues. By overlaying key mutant residues that impacted binding onto a crystal structure of HA, the NR2728 mAb was found to interact with a fully surface-exposed contiguous patch of residues at the receptor binding site (RBS), giving insight into the mechanism underlying its potent inhibition of virus binding. The non-neutralizing H5-2A mAb was similarly mapped to a highly conserved H5 strain-specific but poorly accessible location on a loop at the trimer HA interface. These data further augment our toolchest for studying HA antigenicity, epitope diversity and accessibility in response to natural and experimental influenza infection and vaccines. PMID:21569761

  15. Prophylactic vaccination with phage-displayed epitope of C. albicans elicits protective immune responses against systemic candidiasis in C57BL/6 mice.

    PubMed

    Yang, Qiong; Wang, Li; Lu, Da-ning; Gao, Rui-juan; Song, Jin-na; Hua, Pan-yu; Yuan, Da-wei

    2005-07-01

    Epitope LKVIRK on 47 kDa of heat shock protein (Hsp) 90 of Candida albicans, corresponding to residues 386-391 of the Hsp90, is recognized by patients recovering from invasive candidiasis. The efficacy of hybrid phage displaying epitope LKVIRK in the N-terminal region of the major coat protein (pVIII) in inducing anti-invasive candidiasis immune response was studied in C57BL/6 mice. Indirect phage-ELISA results demonstrated that the mice immunized with hybrid phage had significantly higher titers of epitope LKVIRK-specific serum IgG as compared to those immunized with heat-killed C. albicans (HK-CA). C57BL/6 mice immunized either with hybrid phage or with wild-type phage also developed significant levels of delayed-type hypersensitivity (DTH) response and splenocyte proliferation, as well as with HK-CA. In addition, high levels of IFN-gamma in the CD4(+) splenocytes from phage-immunized mice were detected as well during 1 week post-inoculation. Furthermore, mice immunized with hybrid phage acquired a resistance to systemic C. albicans infection as confirmed by fewer C. albicans cells in the kidneys, and had a longer lifespan compared to control groups following intravenous challenge with C. albicans. These results indicate that hybrid phage displaying epitope LKVIRK may serve as a potential vaccine conferring a resistance to systemic candidiasis.

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

    PubMed Central

    Liu, Jie; Haddad, Elias K.; Marceau, Joshua; Morabito, Kaitlyn M.; Rao, Srinivas S.; Filali-Mouhim, Ali; Sekaly, Rafick-Pierre; Graham, Barney S.

    2016-01-01

    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. PMID:26943673

  17. High-affinity interactions between peptides and heat shock protein 70 augment CD8+ T lymphocyte immune responses.

    PubMed

    Flechtner, Jessica B; Cohane, Kenya Prince; Mehta, Sunil; Slusarewicz, Paul; Leonard, Alexis Kays; Barber, Brian H; Levey, Daniel L; Andjelic, Sofija

    2006-07-15

    Exogenously delivered antigenic peptides complexed to heat shock proteins (HSPs) are able to enter the endogenous Ag-processing pathway and prime CD8+ CTL. It was determined previously that a hybrid peptide containing a MHC class I-binding epitope and HSP70-binding sequence Javelin (J0) in complex with HSP70 could induce cytotoxic T cell responses in vivo that were more robust than those induced by the minimal epitope complexed with HSP70. The present study introduces a novel, higher-affinity HSP70-binding sequence (J1) that significantly enhances binding of various antigenic peptides to HSP70. A competition binding assay revealed a dissociation constant that was 15-fold lower for the H2-K(b) OVA epitope SIINFEKL-J1 compared with SIINFEKL-J0, indicating a substantially higher affinity for HSP70. Further, modifying the orientation of the hybrid epitope and introducing a cleavable linker sequence between the Javelin and the epitope results in even greater immunogenicity, presumably by greater efficiency of epitope processing. The enhanced immunogenicity associated with Javelin J1 and the cleavable linker is consistently observed with multiple mouse and human epitopes. Thus, by creating a series of epitopes with uniform, high-affinity binding to HSP70, successful multiple epitope immunizations are possible, with equal delivery of each antigenic epitope to the immune system via HSP70. These modified epitopes have the potential for creating successful multivalent vaccines for immunotherapy of both infectious disease and cancer.

  18. Effective Treatment of Established GL261 Murine Gliomas through Picornavirus Vaccination-Enhanced Tumor Antigen-Specific CD8+ T Cell Responses.

    PubMed

    Renner, Danielle N; Jin, Fang; Litterman, Adam J; Balgeman, Alexis J; Hanson, Lisa M; Gamez, Jeffrey D; Chae, Michael; Carlson, Brett L; Sarkaria, Jann N; Parney, Ian F; Ohlfest, John R; Pirko, Istvan; Pavelko, Kevin D; Johnson, Aaron J

    2015-01-01

    Glioblastoma (GBM) is among the most invasive and lethal of cancers, frequently infiltrating surrounding healthy tissue and giving rise to rapid recurrence. It is therefore critical to establish experimental model systems and develop therapeutic approaches that enhance anti-tumor immunity. In the current study, we have employed a newly developed murine glioma model to assess the efficacy of a novel picornavirus vaccination approach for the treatment of established tumors. The GL261-Quad system is a variation of the GL261 syngeneic glioma that has been engineered to expresses model T cell epitopes including OVA257-264. MRI revealed that both GL261 and GL261-Quad tumors display characteristic features of human gliomas such as heterogeneous gadolinium leakage and larger T2 weighted volumes. Analysis of brain-infiltrating immune cells demonstrated that GL261-Quad gliomas generate detectable CD8+ T cell responses toward the tumor-specific Kb:OVA257-264 antigen. Enhancing this response via a single intracranial or peripheral vaccination with picornavirus expressing the OVA257-264 antigen increased anti-tumor CD8+ T cells infiltrating the brain, attenuated progression of established tumors, and extended survival of treated mice. Importantly, the efficacy of the picornavirus vaccination is dependent on functional cytotoxic activity of CD8+ T cells, as the beneficial response was completely abrogated in mice lacking perforin expression. Therefore, we have developed a novel system for evaluating mechanisms of anti-tumor immunity in vivo, incorporating the GL261-Quad model, 3D volumetric MRI, and picornavirus vaccination to enhance tumor-specific cytotoxic CD8+ T cell responses and track their effectiveness at eradicating established gliomas in vivo.

  19. Phenotypic Alterations Involved in CD8+ Treg Impairment in Systemic Sclerosis.

    PubMed

    Negrini, Simone; Fenoglio, Daniela; Parodi, Alessia; Kalli, Francesca; Battaglia, Florinda; Nasi, Giorgia; Curto, Monica; Tardito, Samuele; Ferrera, Francesca; Filaci, Gilberto

    2017-01-01

    Systemic sclerosis (SSc) is a connective tissue disease characterized by tissue fibrosis, vasculopathy, and autoimmunity. Although the exact pathogenetic mechanisms behind SSc remain to be fully elucidated, a great deal of evidence suggests the existence of an unbalanced ratio between the effector and regulatory arms of the immune system. With regard to the T regulatory (Treg) compartment, we observed that CD8+ Treg subsets display functional defects in SSc-affected patients. Since CD127 down-modulation and CD39 upregulation have been observed on Treg subsets, the phenotypic expression of these molecules was analyzed on the CD8+CD28- Treg precursors and on CD8+ Treg cells generated in vitro through interleukin-10 commitment. Immunophenotypic data from SSc patients were compared to those obtained from healthy subjects. The analyses performed on ex vivo-isolated CD8+CD28- Treg precursors did not show any significant differences in CD39 or CD127 expression as compared to values obtained from healthy donors. On the contrary, in vitro-generated CD8+ Tregs obtained from SSc patients displayed reduced expression of the CD39 molecule as compared to controls. Moreover, the percentage of CD127+ cells was significantly higher in in vitro-generated CD8+ Tregs from SSc patients compared to CD8+ Tregs obtained from healthy donors. Taken together, these findings may indicate an impairment of maturation processes affecting CD8+ Treg cells in SSc patients. This impairment of maturation involves phenotypic alterations that are mainly characterized by a deficient CD39 upregulation and a lack of down-modulation of the CD127 molecule.

  20. Phenotypic Alterations Involved in CD8+ Treg Impairment in Systemic Sclerosis

    PubMed Central

    Negrini, Simone; Fenoglio, Daniela; Parodi, Alessia; Kalli, Francesca; Battaglia, Florinda; Nasi, Giorgia; Curto, Monica; Tardito, Samuele; Ferrera, Francesca; Filaci, Gilberto

    2017-01-01

    Systemic sclerosis (SSc) is a connective tissue disease characterized by tissue fibrosis, vasculopathy, and autoimmunity. Although the exact pathogenetic mechanisms behind SSc remain to be fully elucidated, a great deal of evidence suggests the existence of an unbalanced ratio between the effector and regulatory arms of the immune system. With regard to the T regulatory (Treg) compartment, we observed that CD8+ Treg subsets display functional defects in SSc-affected patients. Since CD127 down-modulation and CD39 upregulation have been observed on Treg subsets, the phenotypic expression of these molecules was analyzed on the CD8+CD28− Treg precursors and on CD8+ Treg cells generated in vitro through interleukin-10 commitment. Immunophenotypic data from SSc patients were compared to those obtained from healthy subjects. The analyses performed on ex vivo-isolated CD8+CD28− Treg precursors did not show any significant differences in CD39 or CD127 expression as compared to values obtained from healthy donors. On the contrary, in vitro-generated CD8+ Tregs obtained from SSc patients displayed reduced expression of the CD39 molecule as compared to controls. Moreover, the percentage of CD127+ cells was significantly higher in in vitro-generated CD8+ Tregs from SSc patients compared to CD8+ Tregs obtained from healthy donors. Taken together, these findings may indicate an impairment of maturation processes affecting CD8+ Treg cells in SSc patients. This impairment of maturation involves phenotypic alterations that are mainly characterized by a deficient CD39 upregulation and a lack of down-modulation of the CD127 molecule. PMID:28154567

  1. Trypanosoma cruzi Subverts Host Cell Sialylation and May Compromise Antigen-specific CD8+ T Cell Responses*

    PubMed Central

    Freire-de-Lima, Leonardo; Alisson-Silva, Frederico; Carvalho, Sebastião T.; Takiya, Christina M.; Rodrigues, Maurício M.; DosReis, George A.; Mendonça-Previato, Lucia; Previato, José O.; Todeschini, Adriane R.

    2010-01-01

    Upon activation, cytotoxic CD8+ T lymphocytes are desialylated exposing β-galactose residues in a physiological change that enhances their effector activity and that can be monitored on the basis of increased binding of the lectin peanut agglutinin. Herein, we investigated the impact of sialylation mediated by trans-sialidase, a specific and unique Trypanosoma transglycosylase for sialic acid, on CD8+ T cell response of mice infected with T. cruzi. Our data demonstrate that T. cruzi uses its trans-sialidase enzyme to resialylate the CD8+ T cell surface, thereby dampening antigen-specific CD8+ T cell response that might favor its own persistence in the mammalian host. Binding of the monoclonal antibody S7, which recognizes sialic acid-containing epitopes on the 115-kDa isoform of CD43, was augmented on CD8+ T cells from ST3Gal-I-deficient infected mice, indicating that CD43 is one sialic acid acceptor for trans-sialidase activity on the CD8+ T cell surface. The cytotoxic activity of antigen-experienced CD8+ T cells against the immunodominant trans-sialidase synthetic peptide IYNVGQVSI was decreased following active trans-sialidase- mediated resialylation in vitro and in vivo. Inhibition of the parasite's native trans-sialidase activity during infection strongly decreased CD8+ T cell sialylation, reverting it to the glycosylation status expected in the absence of parasite manipulation increasing mouse survival. Taken together, these results demonstrate, for the first time, that T. cruzi subverts sialylation to attenuate CD8+ T cell interactions with peptide-major histocompatibility complex class I complexes. CD8+ T cell resialylation may represent a sophisticated strategy to ensure lifetime host parasitism. PMID:20106975

  2. The use of hybrid phage displaying antigen epitope and recombinant protein in the diagnosis of systemic Candida albicans infection in rabbits and cancer patients.

    PubMed

    Quanping, Su; Yanyan, Huai; Yicun, Wang; Zhigang, Ju; Yuling, Geng; Li, Wang

    2010-12-01

    Hsp90 and Sap2 are 2 immunodominant antigens of Candida albicans. Both of them can induce the production of antibody. In this article, systemically infected rabbits were used to study the Hsp90 and Sap2 antibody production. Also, pET28a-Hsp90 protein, pET28a-Sap2 protein, hybrid phage displaying LKVIRK epitope, and hybrid phage displaying VKYTS epitope were used for diagnosis of the antibody in cancer patients. The results showed that the Sap2 antibody appeared earlier than Hsp90 antibody in systemically infected rabbits. Meanwhile, both of the antibodies can perform protection in rabbits. The conclusion is that Sap2 antibody, which appears at early stage in systemic candidiasis, may be better than Hsp90 antibody for the diagnosis of invasive candidiasis. For 141 sera of cancer patients, 52 sera were detected Sap2 antibody and 57 sera were detected Hsp90 antibody. Only 14 sera contained both the 2 antibodies. Although recombinant protein was slightly more sensitive than hybrid phage, there was no significant difference between them. For its easy preparation, less expensive hybrid phage displaying antigen epitope may be a better agent for diagnosis of candidiasis.

  3. Systematic identification of immunodominant CD8+ T-cell responses to influenza A virus in HLA-A2 individuals

    PubMed Central

    Wu, Chao; Zanker, Damien; Valkenburg, Sophie; Kedzierska, Katherine; Zou, Quan Ming; Doherty, Peter C.; Chen, Weisan

    2011-01-01

    Immunodominant T-cell responses are important for virus clearance. However, the identification of immunodominant T-cell peptide + HLA glycoprotein epitopes has been hindered by the extent of HLA polymorphism and the limitations of predictive algorithms. A simple, systematic approach has been used here to screen for immunodominant CD8+ T-cell specificities. The analysis targeted healthy HLA-A2+ donors to allow comparison with responses to the well-studied influenza matrix protein 1 epitope. Although influenza matrix protein 1 was consistently detected in all individual samples in our study, the response to this epitope was only immunodominant in three of eight, whereas for the other five, prominent CD8+ T-cell responses tended to focus on various peptides from the influenza nucleoprotein that were not presented by HLA-A2. Importantly, with the four immunodominant T-cell epitopes identified here, only one would have been detected by the current prediction programs. The other three peptides would have been either considered too long or classified as not containing typical HLA binding motifs. Our data stress the importance of systematic analysis for discovering HLA-dependent, immunodominant CD8+ T-cell epitopes derived from viruses and tumors. Focusing on HLA-A2 and predictive algorithms may be too limiting as we seek to develop targeted immunotherapy and vaccine strategies that depend on T cell-mediated immunity. PMID:21562214

  4. Differential in vivo clearance and response to secondary heterologous infections by H2(b)-restricted dengue virus-specific CD8+ T cells.

    PubMed

    Beaumier, Coreen M; Jaiswal, Smita; West, Kim Y; Friberg, Heather; Mathew, Anuja; Rothman, Alan L

    2010-10-01

    Cytotoxic T lymphocytes (CTL) are hypothesized to play a role in clearance during primary dengue virus (DENV) infections, and contribute to immunopathology during secondary heterologous infections in humans. We previously reported skewed T-cell responses to secondary DENV infection in BALB/c (H-2(d)) mice, reproducing characteristics of human DENV infection. To set the stage for using widely available transgenic and knockout mice, we extended these studies to identify DENV-specific T-cell responses in C57BL/6 (H-2(b)) mice. We identified dominant CD8+ T-cell responses to H-2D(b)-restricted epitopes on the DENV NS4a (aa 249-265) and NS5 (aa 521-537) proteins. High frequencies of IFN-γ- and TNF-α-producing T cells directed at both epitopes were detected following primary infection with all four DENV serotypes, and were augmented by secondary DENV infections. In vivo cytotoxicity assays demonstrated rapid clearance of target cells pulsed with the NS4a peptide; in contrast, NS5 peptide-pulsed target cells were poorly cleared in vivo. These data characterize two H-2(b)-restricted T-cell epitopes displaying divergent in vivo function. These results should facilitate further studies of the in vivo effects of DENV-specific T cells, including the use of genetically modified mouse strains.

  5. Protection of rhesus macaques against disease progression from pathogenic SHIV-89.6PD by vaccination with phage-displayed HIV-1 epitopes.

    PubMed

    Chen, X; Scala, G; Quinto, I; Liu, W; Chun, T W; Justement, J S; Cohen, O J; vanCott, T C; Iwanicki, M; Lewis, M G; Greenhouse, J; Barry, T; Venzon, D; Fauci, A S

    2001-11-01

    The antigenic polymorphism of HIV-1 is a major obstacle in developing an effective vaccine. Accordingly, we screened random peptide libraries (RPLs) displayed on phage with antibodies from HIV-infected individuals and identified an array of HIV-specific epitopes that behave as antigenic mimics of conformational epitopes of gp120 and gp41 proteins. We report that the selected epitopes are shared by a collection of HIV-1 isolates of clades A-F. The phage-borne epitopes are immunogenic in rhesus macaques, where they elicit envelope-specific antibody responses. Upon intravenous challenge with 60 MID50 of pathogenic SHIV-89.6PD, all monkeys became infected; however, in contrast to the naive and mock-immunized monkeys, four of five mimotope-immunized monkeys experienced lower levels of peak viremia, followed by viral set points of undetectable or transient levels of viremia and a mild decline of CD4+ T cells, and were protected from progression to AIDS-like illness. These results provide a new approach to the design of broadly protective HIV-1 vaccines.

  6. Identification of a Conserved Linear B-Cell Epitope of Streptococcus dysgalactiae GapC Protein by Screening Phage-Displayed Random Peptide Library

    PubMed Central

    Fan, Ziyao; Zhou, Xue; Yu, Liquan; Sun, Hunan; Wu, Zhijun; Yu, Yongzhong; Song, Baifen; Ma, Jinzhu; Tong, Chunyu; Wang, Xintong; Zhu, Zhanbo; Cui, Yudong

    2015-01-01

    The GapC of Streptococcus dysgalactiae (S. dysgalactiae) is a highly conserved surface protein that can induce protective humoral immune response in animals. However, B-cell epitopes on the S. dysgalactiae GapC have not been well identified. In this study, a monoclonal antibody (mAb5B7) against the GapC1-150 protein was prepared. After passive transfer, mAb5B7 could partially protect mice against S. dysgalactiae infection. Eleven positive phage clones recognized by mAb5B7 were identified by screening phage-displayed random 12-peptide library, most of which matched the consensus motif DTTQGRFD. The motif sequence exactly matches amino acids 48-55 of the S. dysgalactiae GapC protein. In addition, the motif 48DTTQGRFD55 shows high homology among various streptococcus species. Site-directed mutagenic analysis further confirmed that residues D48, T50, Q51, G52 and F54 formed the core motif of 48DTTQGRFD55. This motif was the minimal determinant of the B-cell epitope recognized by the mAb5B7. As expected, epitope-peptide evoked protective immune response against S. dysgalactiae infection in immunized mice. Taken together, this identified conserved B-cell epitope within S. dysgalactiae GapC could provide very valuable insights for vaccine design against S. dysgalactiae infection. PMID:26121648

  7. Vaccine generated immunity targets an HPV16 E7 HLA-A2.1-restricted CD8(+) T cell epitope relocated to an early gene or a late gene of the cottontail rabbit papillomavirus (CRPV) genome in HLA-A2.1 transgenic rabbits.

    PubMed

    Bounds, Callie E; Hu, Jiafen; Cladel, Nancy M; Balogh, Karla; Christensen, Neil D

    2011-02-01

    The newly established HLA-A2.1 transgenic rabbit model has proven useful for testing the immunogenicity of well known and computer-predicted A2-restricted epitopes. In the current study we compared the protective immunity induced to a preferred HPV16 E7 A2-restricted epitope that has been relocated to positions within the CRPV E7 gene and the CRPV L2 gene. Epitope expression from both the E7 protein and the L2 protein resulted in increased protection against viral DNA challenge of the HLA-A2.1 transgenic rabbits as compared to control-vaccinated rabbit groups. These data indicate that proteins expressed at both early and late time points during a natural papillomavirus infection can be targeted by epitope-specific immunity and indicate this immunity is increased to early rather than late expressed proteins of papillomaviruses. This study also highlights the broad utility of the HLAA2.1 transgenic rabbit model for testing numerous immunological factors involved in vaccine generated protective immunity.

  8. Short-Lived Effector CD8 T Cells Induced by Genetically Attenuated Malaria Parasite Vaccination Express CD11c

    PubMed Central

    Cooney, Laura A.; Gupta, Megha; Thomas, Sunil; Mikolajczak, Sebastian; Choi, Kimberly Y.; Gibson, Claire; Jang, Ihn K.; Danziger, Sam; Aitchison, John; Gardner, Malcolm J.; Kappe, Stefan H. I.

    2013-01-01

    Vaccination with a single dose of genetically attenuated malaria parasites can induce sterile protection against sporozoite challenge in the rodent Plasmodium yoelii model. Protection is dependent on CD8+ T cells, involves perforin and gamma interferon (IFN-γ), and is correlated with the expansion of effector memory CD8+ T cells in the liver. Here, we have further characterized vaccine-induced changes in the CD8+ T cell phenotype and demonstrated significant upregulation of CD11c on CD3+ CD8b+ T cells in the liver, spleen, and peripheral blood. CD11c+ CD8+ T cells are predominantly CD11ahi CD44hi CD62L−, indicative of antigen-experienced effector cells. Following in vitro restimulation with malaria-infected hepatocytes, CD11c+ CD8+ T cells expressed inflammatory cytokines and cytotoxicity markers, including IFN-γ, tumor necrosis factor alpha (TNF-α), interleukin-2 (IL-2), perforin, and CD107a. CD11c− CD8+ T cells, on the other hand, expressed negligible amounts of all inflammatory cytokines and cytotoxicity markers tested, indicating that CD11c marks multifunctional effector CD8+ T cells. Coculture of CD11c+, but not CD11c−, CD8+ T cells with sporozoite-infected primary hepatocytes significantly inhibited liver-stage parasite development. Tetramer staining for the immunodominant circumsporozoite protein (CSP)-specific CD8+ T cell epitope demonstrated that approximately two-thirds of CSP-specific cells expressed CD11c at the peak of the CD11c+ CD8+ T cell response, but CD11c expression was lost as the CD8+ T cells entered the memory phase. Further analyses showed that CD11c+ CD8+ T cells are primarily KLRG1+ CD127− terminal effectors, whereas all KLRG1− CD127+ memory precursor effector cells are CD11c− CD8+ T cells. Together, these results suggest that CD11c marks a subset of highly inflammatory, short-lived, antigen-specific effector cells, which may play an important role in eliminating infected hepatocytes. PMID:23980113

  9. Intrinsic transgene immunogenicity gears CD8(+) T-cell priming after rAAV-mediated muscle gene transfer.

    PubMed

    Carpentier, Maxime; Lorain, Stéphanie; Chappert, Pascal; Lalfer, Mélanie; Hardet, Romain; Urbain, Dominique; Peccate, Cécile; Adriouch, Sahil; Garcia, Luis; Davoust, Jean; Gross, David-Alexandre

    2015-04-01

    Antitransgene CD8(+) T-cell responses are an important hurdle after recombinant adeno-associated virus (rAAV) vector-mediated gene transfer. Indeed, depending on the mutational genotype of the host, transgene amino-acid sequences of foreign origin can elicit deleterious cellular and humoral responses. We compared here two different major histocompatibility complex (MHC) class I epitopes of an engineered ovalbumin transgene delivered in muscle tissue by rAAV1 vector and found very different strength of CD8 responses, muscle destruction being correlated with the course of the immunodominant response. We further demonstrate that robust CD8(+) T-cell priming can occur through the cross-presentation pathway but requires the presence of either a strong MHC class II epitope or antibodies to the transgene product. Finally, manipulating transgene subcellular localization, we found that provided we avoid transgene expression in antigen presenting cells, the poorly accessible cytosolic form of ovalbumin transgene lacking strong MHC II epitope, evades CD8(+) T-cell priming and remains permanently expressed in muscle with no immune cell infiltration. Our results demonstrate that the intrinsic immunogenicity of transgenes delivered with rAAV vector in muscle can be manipulated in a rational manner to avoid adverse immune responses.

  10. Intrinsic Transgene Immunogenicity Gears CD8(+) T-cell Priming After rAAV-Mediated Muscle Gene Transfer.

    PubMed

    Carpentier, Maxime; Lorain, Stéphanie; Chappert, Pascal; Lalfer, Mélanie; Hardet, Romain; Urbain, Dominique; Peccate, Cécile; Adriouch, Sahil; Garcia, Luis; Davoust, Jean; Gross, David-Alexandre

    2015-04-01

    Antitransgene CD8(+) T-cell responses are an important hurdle after recombinant adeno-associated virus (rAAV) vector-mediated gene transfer. Indeed, depending on the mutational genotype of the host, transgene amino-acid sequences of foreign origin can elicit deleterious cellular and humoral responses. We compared here two different major histocompatibility complex (MHC) class I epitopes of an engineered ovalbumin transgene delivered in muscle tissue by rAAV1 vector and found very different strength of CD8 responses, muscle destruction being correlated with the course of the immunodominant response. We further demonstrate that robust CD8(+) T-cell priming can occur through the cross-presentation pathway but requires the presence of either a strong MHC class II epitope or antibodies to the transgene product. Finally, manipulating transgene subcellular localization, we found that provided we avoid transgene expression in antigen presenting cells, the poorly accessible cytosolic form of ovalbumin transgene lacking strong MHC II epitope, evades CD8(+) T-cell priming and remains permanently expressed in muscle with no immune cell infiltration. Our results demonstrate that the intrinsic immunogenicity of transgenes delivered with rAAV vector in muscle can be manipulated in a rational manner to avoid adverse immune responses.

  11. Structure-based design of a protein immunogen that displays an HIV-1 gp41 neutralizing epitope.

    PubMed

    Stanfield, Robyn L; Julien, Jean-Philippe; Pejchal, Robert; Gach, Johannes S; Zwick, Michael B; Wilson, Ian A

    2011-12-02

    Antibody Z13e1 is a relatively broadly neutralizing anti-human immunodeficiency virus type 1 antibody that recognizes the membrane-proximal external region (MPER) of the human immunodeficiency virus type 1 envelope glycoprotein gp41. Based on the crystal structure of an MPER epitope peptide in complex with Z13e1 Fab, we identified an unrelated protein, interleukin (IL)-22, with a surface-exposed region that is structurally homologous in its backbone to the gp41 Z13e1 epitope. By grafting the gp41 Z13e1 epitope sequence onto the structurally homologous region in IL-22, we engineered a novel protein (Z13-IL22-2) that contains the MPER epitope sequence for use as a potential immunogen and as a reagent for the detection of Z13e1-like antibodies. The Z13-IL22-2 protein binds Fab Z13e1 with a K(d) of 73 nM. The crystal structure of Z13-IL22-2 in complex with Fab Z13e1 shows that the epitope region is faithfully replicated in the Fab-bound scaffold protein; however, isothermal calorimetry studies indicate that Fab binding to Z13-IL22-2 is not a lock-and-key event, leaving open the question of whether conformational changes upon binding occur in the Fab, in Z13-IL-22, or in both.

  12. Structure-Based Design of a Protein Immunogen that Displays an HIV-1 gp41 Neutralizing Epitope

    SciTech Connect

    Stanfield, Robyn L.; Julien, Jean-Philippe; Pejchal, Robert; Gach, Johannes S.; Zwick, Michael B.; Wilson, Ian A.

    2012-06-27

    Antibody Z13e1 is a relatively broadly neutralizing anti-human immunodeficiency virus type 1 antibody that recognizes the membrane-proximal external region (MPER) of the human immunodeficiency virus type 1 envelope glycoprotein gp41. Based on the crystal structure of an MPER epitope peptide in complex with Z13e1 Fab, we identified an unrelated protein, interleukin (IL)-22, with a surface-exposed region that is structurally homologous in its backbone to the gp41 Z13e1 epitope. By grafting the gp41 Z13e1 epitope sequence onto the structurally homologous region in IL-22, we engineered a novel protein (Z13-IL22-2) that contains the MPER epitope sequence for use as a potential immunogen and as a reagent for the detection of Z13e1-like antibodies. The Z13-IL22-2 protein binds Fab Z13e1 with a K{sub d} of 73 nM. The crystal structure of Z13-IL22-2 in complex with Fab Z13e1 shows that the epitope region is faithfully replicated in the Fab-bound scaffold protein; however, isothermal calorimetry studies indicate that Fab binding to Z13-IL22-2 is not a lock-and-key event, leaving open the question of whether conformational changes upon binding occur in the Fab, in Z13-IL-22, or in both.

  13. Multiple specificities in the murine CD4+ and CD8+ T-cell response to dengue virus.

    PubMed Central

    Rothman, A L; Kurane, I; Ennis, F A

    1996-01-01

    The target epitopes, serotype specificity, and cytolytic function of dengue virus-specific T cells may influence their theoretical roles in protection against secondary infection as well as the immunopathogenesis of dengue hemorrhagic fever. To study these factors in an experimental system, we isolated dengue virus-specific CD4+ and CD8+ T-cell clones from dengue-2 virus-immunized BALB/c mice. The T-cell response to dengue virus in this mouse strain was heterogeneous; we identified at least five different CD4+ phenotypes and six different CD8+ phenotypes. Individual T-cell clones recognized epitopes on the dengue virus pre-M, E, NSl/NS2A, and NS3 proteins and were restricted by the I-Ad, I-Ed, Ld, and Kd antigens. Both serotype-specific and serotype-cross-reactive clones were isolated in the CD4+ and CD8+ subsets; among CD8+ clones, those that recognized the dengue virus structural proteins were serotype specific whereas those that recognized the nonstructural proteins were serotype cross-reactive. All of the CD8+ and one of five CD4+ clones lysed dengue virus-infected target cells. Using synthetic peptides, we identified an Ld-restricted epitope on the E protein (residues 331 to 339, SPCKIPFEI) and a Kd-restricted epitope on the NS3 protein (residues 296 to 310, ARGYISTRVEM GEAA). These data parallel previous findings of studies using human dengue virus-specific T-cell clones. This experimental mouse system may be useful for studying the role of the virus serotype and HLA haplotype on T-cell responses after primary dengue virus infection. PMID:8794288

  14. Dominant influence of an HLA-B27 restricted CD8+ T cell response in mediating HCV clearance and evolution.

    PubMed

    Neumann-Haefelin, Christoph; McKiernan, Susan; Ward, Scott; Viazov, Sergei; Spangenberg, Hans Christian; Killinger, Thomas; Baumert, Thomas F; Nazarova, Natalja; Sheridan, Isabelle; Pybus, Oliver; von Weizsäcker, Fritz; Roggendorf, Michael; Kelleher, Dermot; Klenerman, Paul; Blum, Hubert E; Thimme, Robert

    2006-03-01

    Virus-specific CD8+ T cell responses play an important role in the natural course of infection; however, the impact of certain CD8+ T cell responses in determining clinical outcome has not been fully defined. A well-defined cohort of women inoculated with HCV from a single source showed that HLA-B27 has a strong association with spontaneous clearance. The immunological basis for this association is unknown. However, the finding is especially significant because HLA-B27 has also been shown to have a protective role in HIV infection. We report the identification of an HLA-B27 restricted hepatitis C virus (HCV)-specific CD8+ T cell epitope that is recognized in the majority of recovered HLA-B27 positive women. In chronically HCV-infected individuals, analysis of the corresponding viral sequence showed a strong association between sequence variations within this epitope and expression of HLA-B27, indicating allele-specific selection pressure at the population level. Functional analysis in 3 chronically HCV-infected patients showed that the emerging variant viral epitopes represent escape mutations. In conclusion, our results suggest a dominant role of HLA-B27 in mediating spontaneous viral clearance as well as viral evolution in HCV infection and mechanistically link both associations to a dominant novel CD8+ T cell epitope. These results support the central role of virus-specific CD8+ T cells and the genetically determined restriction of the virus-specific T cell repertoire in HCV infection.

  15. Distinct Kinetics of Effector CD8+ Cytotoxic T Cells after Infection with Trypanosoma cruzi in Naïve or Vaccinated Mice

    PubMed Central

    Tzelepis, Fanny; de Alencar, Bruna C. G.; Penido, Marcus L. O.; Gazzinelli, Ricardo T.; Persechini, Pedro M.; Rodrigues, Mauricio M.

    2006-01-01

    The kinetics of effector CD8+-T-cell responses to specific Trypanosoma cruzi epitopes was investigated after challenge. Our results suggest that the delayed kinetics differs from that observed in other microbial infections and facilitates the establishment of the disease in naïve mice. In contrast, in vaccinated mice, the swift CD8+-T-cell response helps host survival after challenge. PMID:16552083

  16. Private specificities of CD8 T cell responses control patterns of heterologous immunity

    PubMed Central

    Kim, Sung-Kwon; Cornberg, Markus; Wang, Xiaoting Z.; Chen, Hong D.; Selin, Liisa K.; Welsh, Raymond M.

    2005-01-01

    CD8 T cell cross-reactivity between viruses can play roles in protective heterologous immunity and damaging immunopathology. This cross-reactivity is sometimes predictable, such as between lymphocytic choriomeningitis virus (LCMV) and Pichinde virus, where cross-reactive epitopes share six out of eight amino acids. Here, however, we demonstrate more subtle and less predictable cross-reactivity between LCMV and the unrelated vaccinia virus (VV). Epitope-specific T cell receptor usage differed between individual LCMV-infected C57BL/6 mice, even though the mice had similar epitope-specific T cell hierarchies. LCMV-immune mice challenged with VV showed variations, albeit in a distinct hierarchy, in proliferative expansions of and down-regulation of IL-7Rα by T cells specific to different LCMV epitopes. T cell responses to a VV-encoded epitope that is cross-reactive with LCMV fluctuated greatly in VV-infected LCMV-immune mice. Adoptive transfers of splenocytes from individual LCMV-immune donors resulted in nearly identical VV-induced responses in each of several recipients, but responses differed depending on the donor. This indicates that the specificities of T cell responses that are not shared between individuals may influence cross-reactivity with other antigens and play roles in heterologous immunity upon encounter with another pathogen. This variability in cross-reactive T cell expansion that is unique to the individual may underlie variation in the pathogenesis of infectious diseases. PMID:15710651

  17. Extensive Polymorphism and Evidence of Immune Selection in a Highly Dominant Antigen Recognized by Bovine CD8 T Cells Specific for Theileria annulata▿†‖

    PubMed Central

    MacHugh, Niall D.; Weir, William; Burrells, Alison; Lizundia, Regina; Graham, Simon P.; Taracha, Evans L.; Shiels, Brian R.; Langsley, Gordon; Morrison, W. Ivan

    2011-01-01

    Although parasite strain-restricted CD8 T cell responses have been described for several protozoa, the precise role of antigenic variability in immunity is poorly understood. The tick-borne protozoan parasite Theileria annulata infects leukocytes and causes an acute, often fatal lymphoproliferative disease in cattle. Building on previous evidence of strain-restricted CD8 T cell responses to T. annulata, this study set out to identify and characterize the variability of the target antigens. Three antigens were identified by screening expressed parasite cDNAs with specific CD8 T cell lines. In cattle expressing the A10 class I major histocompatibility complex haplotype, A10-restricted CD8 T cell responses were shown to be focused entirely on a single dominant epitope in one of these antigens (Ta9). Sequencing of the Ta9 gene from field isolates of T. annulata demonstrated extensive sequence divergence, resulting in amino acid polymorphism within the A10-restricted epitope and a second A14-restricted epitope. Statistical analysis of the allelic sequences revealed evidence of positive selection for amino acid substitutions within the region encoding the CD8 T cell epitopes. Sequence differences in the A10-restricted epitope were shown to result in differential recognition by individual CD8 T cell clones, while clones also differed in their ability to recognize different alleles. Moreover, the representation of these clonal specificities within the responding CD8 T cell populations differed between animals. As well as providing an explanation for incomplete protection observed after heterologous parasite challenge of vaccinated cattle, these results have important implications for the choice of antigens for the development of novel subunit vaccines. PMID:21300773

  18. Variable epitope library carrying heavily mutated survivin-derived CTL epitope variants as a new class of efficient vaccine immunogen tested in a mouse model of breast cancer

    PubMed Central

    NoeDominguez-Romero, Allan; Zamora-Alvarado, Rubén; Servín-Blanco, Rodolfo; Pérez-Hernández, Erendira G; Castrillon-Rivera, Laura E; Munguia, Maria Elena; Acero, Gonzalo; Govezensky, Tzipe; Gevorkian, Goar; Manoutcharian, Karen

    2014-01-01

    The antigenic variability of tumor cells leading to dynamic changes in cancer epitope landscape along with escape from immune surveillance by down-regulating tumor antigen expression/presentation and immune tolerance are major obstacles for the design of effective vaccines. We have developed a novel concept for immunogen construction based on introduction of massive mutations within the epitopes targeting antigenically variable pathogens and diseases. Previously, we showed that these immunogens carrying large combinatorial libraries of mutated epitope variants, termed as variable epitope libraries (VELs), induce potent, broad and long lasting CD8+IFN-γ+ T-cell response as well as HIV-neutralizing antibodies. In this proof-of-concept study, we tested immunogenic properties and anti-tumor effects of the VELs bearing survivin-derived CTL epitope (GWEPDDNPI) variants in an aggressive metastatic mouse 4T1 breast tumor model. The constructed VELs had complexities of 10,500 and 8,000 individual members, generated as combinatorial M13 phage display and synthetic peptide libraries, respectively, with structural composition GWXPXDXPI, where X is any of 20 natural amino acids. Statistically significant tumor growth inhibition was observed in BALB/c mice immunized with the VELs in both prophylactic and therapeutic settings. Vaccinated mice developed epitope-specific spleen cell and CD8+ IFN-γ+ T-cell responses that recognize more than 50% of the panel of 87 mutated epitope variants, as demonstrated in T-cell proliferation assays and FACS analysis. These data indicate the feasibility of the application of this new class of immunogens based on VEL concept as an alternative approach for the development of molecular vaccines against cancer. PMID:25483665

  19. Variable epitope library carrying heavily mutated survivin-derived CTL epitope variants as a new class of efficient vaccine immunogen tested in a mouse model of breast cancer.

    PubMed

    NoeDominguez-Romero, Allan; Zamora-Alvarado, Rubén; Servín-Blanco, Rodolfo; Pérez-Hernández, Erendira G; Castrillon-Rivera, Laura E; Munguia, Maria Elena; Acero, Gonzalo; Govezensky, Tzipe; Gevorkian, Goar; Manoutcharian, Karen

    2014-01-01

    The antigenic variability of tumor cells leading to dynamic changes in cancer epitope landscape along with escape from immune surveillance by down-regulating tumor antigen expression/presentation and immune tolerance are major obstacles for the design of effective vaccines. We have developed a novel concept for immunogen construction based on introduction of massive mutations within the epitopes targeting antigenically variable pathogens and diseases. Previously, we showed that these immunogens carrying large combinatorial libraries of mutated epitope variants, termed as variable epitope libraries (VELs), induce potent, broad and long lasting CD8+IFN-γ+ T-cell response as well as HIV-neutralizing antibodies. In this proof-of-concept study, we tested immunogenic properties and anti-tumor effects of the VELs bearing survivin-derived CTL epitope (GWEPDDNPI) variants in an aggressive metastatic mouse 4T1 breast tumor model. The constructed VELs had complexities of 10,500 and 8,000 individual members, generated as combinatorial M13 phage display and synthetic peptide libraries, respectively, with structural composition GWXPXDXPI, where X is any of 20 natural amino acids. Statistically significant tumor growth inhibition was observed in BALB/c mice immunized with the VELs in both prophylactic and therapeutic settings. Vaccinated mice developed epitope-specific spleen cell and CD8+ IFN-γ+ T-cell responses that recognize more than 50% of the panel of 87 mutated epitope variants, as demonstrated in T-cell proliferation assays and FACS analysis. These data indicate the feasibility of the application of this new class of immunogens based on VEL concept as an alternative approach for the development of molecular vaccines against cancer.

  20. Differential targeting of viral components by CD4+ versus CD8+ T lymphocytes in dengue virus infection.

    PubMed

    Rivino, Laura; Kumaran, Emmanuelle A P; Jovanovic, Vojislav; Nadua, Karen; Teo, En Wei; Pang, Shyue Wei; Teo, Guo Hui; Gan, Victor Chih Hao; Lye, David C; Leo, Yee Sin; Hanson, Brendon J; Smith, Kenneth G C; Bertoletti, Antonio; Kemeny, David M; MacAry, Paul A

    2013-03-01

    Dengue virus (DENV) is the principal arthropod-borne viral pathogen afflicting human populations. While repertoires of antibodies to DENV have been linked to protection or enhanced infection, the role of T lymphocytes in these processes remains poorly defined. This study provides a comprehensive overview of CD4(+) and CD8(+) T cell epitope reactivities against the DENV 2 proteome in adult patients experiencing secondary DENV infection. Dengue virus-specific T cell responses directed against an overlapping 15mer peptide library spanning the DENV 2 proteome were analyzed ex vivo by enzyme-linked immunosorbent spot assay, and recognition of individual peptides was further characterized in specific T cell lines. Thirty novel T cell epitopes were identified, 9 of which are CD4(+) and 21 are CD8(+) T cell epitopes. We observe that whereas CD8(+) T cell epitopes preferentially target nonstructural proteins (NS3 and NS5), CD4(+) epitopes are skewed toward recognition of viral components that are also targeted by B lymphocytes (envelope, capsid, and NS1). Consistently, a large proportion of dengue virus-specific CD4(+) T cells have phenotypic characteristics of circulating follicular helper T cells (CXCR5 expression and production of interleukin-21 or gamma interferon), suggesting that they are interacting with B cells in vivo. This study shows that during a dengue virus infection, the protein targets of human CD4(+) and CD8(+) T cells are largely distinct, thus highlighting key differences in the immunodominance of DENV proteins for these two cell types. This has important implications for our understanding of how the two arms of the human adaptive immune system are differentially targeted and employed as part of our response to DENV infection.

  1. Killing of Targets by CD8+ T Cells in the Mouse Spleen Follows the Law of Mass Action

    PubMed Central

    Ganusov, Vitaly V.; Barber, Daniel L.; De Boer, Rob J.

    2011-01-01

    It has been difficult to correlate the quality of CD8 T cell responses with protection against viral infections. To investigate the relationship between efficacy and magnitude of T cell responses, we quantify the rate at which individual CD8 effector and memory T cells kill target cells in the mouse spleen. Using mathematical modeling, we analyze recent data on the loss of target cells pulsed with three different peptides from the mouse lymphocytic choriomeningitis virus (LCMV) in mouse spleens with varying numbers of epitope-specific CD8 T cells. We find that the killing of targets follows the law of mass-action, i.e., the death rate of individual target cells remains proportional to the frequency (or the total number) of specific CD8 T cells in the spleen despite the fact that effector cell densities and effector to target ratios vary about a 1000-fold. The killing rate of LCMV-specific CD8 T cells is largely independent of T cell specificity and differentiation stage. Our results thus allow one to calculate the critical T cell concentration at which growth of a virus with a given replication rate can be prevented from the start of infection by memory CD8 T cell response. PMID:21283669

  2. Full-Breadth Analysis of CD8+ T-Cell Responses in Acute Hepatitis C Virus Infection and Early Therapy

    PubMed Central

    Lauer, Georg M.; Lucas, Michaela; Timm, Joerg; Ouchi, Kei; Kim, Arthur Y.; Day, Cheryl L.; zur Wiesch, Julian Schulze; 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.

    2005-01-01

    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

  3. Prolonged presence of effector-memory CD8 T cells in the central nervous system after dengue virus encephalitis.

    PubMed

    van der Most, Robbert G; Murali-Krishna, Kaja; Ahmed, Rafi

    2003-01-01

    Dengue virus infection in the central nervous system (CNS) of immunized mice results in a strong influx of CD8 T cells into the brain. Whereas the kinetics of the splenic antiviral response are conventional, i.e. expansion followed by a rapid drop in the frequency of specific CD8 T cells, dengue virus-specific CD8 T cells are retained in the CNS at a high frequency. These CD8 T cells display a partially activated phenotype (CD69(high), Ly-6A/E(high), CD62L(low)), characteristic for effector-memory T cells. CD43 expression, visualized by staining with the 1B11 mAb, decreased in time, suggesting that these persisting CD8 T cells differentiated into memory cells. These data add to the growing evidence implicating the CNS as a non-lymphoid tissue capable of supporting prolonged T cell survival/maintenance.

  4. Definition of the HLA-A2 restricted peptides recognized by human CD8+ effector T cells by flow-assisted sorting of the CD8+ CD45RA+ CD28- T cell subpopulation.

    PubMed

    Höhn, H; Jülch, M; Pilch, H; Kortsik, C; Tully, G; Neukirch, C; Freitag, K; Maeurer, M

    2003-01-01

    In response to antigenic stimulation, naive MHC-class I restricted and antigen-specific CD8+ CD45RA+ CD28+ T cells undergo clonal expansion, differentiate into CD8+ CD45RO+ memory T cells and convert to CD8+ CD45RA+ CD28- T cells displaying potent immune effector functions upon re-encounter with the nominal antigen. We show that the effector CD8+ CD45RA+ CD28- T cell subset is expanded in peripheral blood lymphocytes (PBL) from patients with human papilloma virus (HPV)+ cervical lesions as well as in PBL from patients with pulmonary tuberculosis. Flow-cytometric cell sorted CD8+ CD45RA+ CD28- and CD8+ CD45RA+ CD28- T cells were tested for recognition of HLA-A2 restricted peptides derived either from the human papillomavirus (HPV)16-E7 gene product, or from M. tuberculosis antigens. Mostly CD8+ CD45+ CD28- T cells define antigen/peptide-specific and MHC-restricted responses. These data were confirmed in PBL from patients with tuberculosis using HLA-A2 tetramer-complexes loaded with a peptide from the M. tuberculosis Ag85b antigen by flow cytometry. The sorting of this T cell subset enables to determine the fine specificity of CD8+ effector T cells without the need for in vitro manipulation.

  5. CD8 T cells and Mycobacterium tuberculosis infection.

    PubMed

    Lin, Philana Ling; Flynn, JoAnne L

    2015-05-01

    Tuberculosis is primarily a respiratory disease that is caused by Mycobacterium tuberculosis. M. tuberculosis can persist and replicate in macrophages in vivo, usually in organized cellular structures called granulomas. There is substantial evidence for the importance of CD4 T cells in control of tuberculosis, but the evidence for a requirement for CD8 T cells in this infection has not been proven in humans. However, animal model data support a non-redundant role for CD8 T cells in control of M. tuberculosis infection. In humans, infection with this pathogen leads to generation of specific CD8 T cell responses. These responses include classical (MHC Class I restricted) and non-classical CD8 T cells. Here, we discuss the potential roles of CD8 T cells in defense against tuberculosis, and our current understanding of the wide range of CD8 T cell types seen in M. tuberculosis infection.

  6. Comprehensive mapping of functional epitopes on dengue virus glycoprotein E DIII for binding to broadly neutralizing antibodies 4E11 and 4E5A by phage display.

    PubMed

    Frei, Julia C; Kielian, Margaret; Lai, Jonathan R

    2015-11-01

    Here we investigated the binding of Dengue virus envelope glycoprotein domain III (DIII) by two broadly neutralizing antibodies (bNAbs), 4E11 and 4E5A. There are four serotypes of Dengue virus (DENV-1 to -4), whose DIII sequences vary by up to 49%. We used combinatorial alanine scanning mutagenesis, a phage display approach, to map functional epitopes (those residues that contribute most significantly to the energetics of antibody-antigen interaction) on these four serotypes. Our results showed that 4E11, which binds strongly to DENV-1, -2, and -3, and moderately to DENV-4, recognized a common conserved core functional epitope involving DIII residues K310, L/I387, L389, and W391. There were also unique recognition features for each serotype, suggesting that 4E11 has flexible recognition requirements. Similar scanning studies for the related bNAb 4E5A, which binds more tightly to DENV-4, identified broader functional epitopes on DENV-1. These results provide useful information for immunogen and therapeutic antibody design.

  7. Targeting Non-classical Myelin Epitopes to Treat Experimental Autoimmune Encephalomyelitis

    PubMed Central

    Wang, Xiaohua; Zhang, Jintao; Baylink, David J.; Li, Chih-Huang; Watts, Douglas M.; Xu, Yi; Qin, Xuezhong; Walter, Michael H.; Tang, Xiaolei

    2016-01-01

    Qa-1 epitopes, the peptides that bind to non-classical major histocompatibility complex Ib Qa-1 molecules and are recognized by Qa-1-restricted CD8+ regulatory T (Treg) cells, have been identified in pathogenic autoimmune cells that attack myelin sheath in experimental autoimmune encephalomyelitis (EAE, an animal model for multiple sclerosis [MS]). Additionally, immunization with such epitopes ameliorates the EAE. However, identification of such epitopes requires knowledge of the pathogenic autoimmune cells which are largely unknown in MS patients. Hence, we asked whether the CD8+ Treg cells could directly target the myelin sheath to ameliorate EAE. To address this question, we analyzed Qa-1 epitopes in myelin oligodendrocyte glycoprotein (MOG that is a protein in myelin sheath). Here, we report identification of a MOG-specific Qa-1 epitope. Immunization with this epitope suppressed ongoing EAE, which was abrogated by CD8+ T cell depletion. Additionally, the epitope immunization activated the epitope-specific CD8+ T cells which specifically accumulated in the CNS-draining cervical lymph nodes. Finally, CD8+ T cells primed by the epitope immunization transferred EAE suppression. Hence, this study reveals a novel regulatory mechanism mediated by the CD8+ Treg cells. We propose that immunization with myelin-specific HLA-E epitopes (human homologues of Qa-1 epitopes) is a promising therapy for MS. PMID:27796368

  8. CD8+ T Cells in Leishmania Infections: Friends or Foes?

    PubMed Central

    Stäger, Simona; Rafati, Sima

    2012-01-01

    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 of Leishmania infections, following vaccination, and as potential immunotherapeutic targets. PMID:22566891

  9. Consensus nomenclature for CD8(+) T cell phenotypes in cancer.

    PubMed

    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

    2015-04-01

    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.

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

    PubMed Central

    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

  11. Impaired functional responses in follicular lymphoma CD8(+)TIM-3(+) T lymphocytes following TCR engagement.

    PubMed

    Gravelle, Pauline; Do, Catherine; Franchet, Camille; Mueller, Sabina; Oberic, Lucie; Ysebaert, Loïc; Larocca, Luigi Maria; Hohaus, Stefan; Calmels, Marie-Noëlle; Frenois, François-Xavier; Kridel, Robert; Gascoyne, Randy D; Laurent, Guy; Brousset, Pierre; Valitutti, Salvatore; Laurent, Camille

    2016-01-01

    Upregulation of T cell immunoglobulin-3 (TIM-3) has been associated with negative regulation of the immune response in chronic infection and cancer, including lymphoma. Here, we investigated the possible correlation between TIM-3 expression by ex vivo cytotoxic T cells (CTL) from follicular lymphoma (FL) biopsies and their functional unresponsiveness that could limit the favorable impact of CTL on disease progression. We report a high percentage of CD8(+)TIM-3(+)T cells in lymph nodes of FL patients. When compared to their CD8(+)TIM-3(-) counterparts, CD8(+)TIM-3(+) T cells exhibited defective cytokine production following TCR engagement. Furthermore, CD8(+)TIM-3(+) T cells display ex vivo markers of lytic granule release and remain unresponsive to further TCR-induced activation of the lytic machinery. Although confocal microscopy showed that TIM-3 expression on CD8(+) T cells correlated with minor alterations of immunological synapse, a selective reduction of ERK signaling in CD8(+)TIM-3(+)T cells was observed by phospho-flow analysis. Finally, short relapse-free survival despite rituximab(R)-chemotherapy was observed in patients with high content of TIM-3(+) cells and a poor infiltrate of granzyme B(+) T cells in FL lymph nodes. Together, our data indicate that, besides selective TCR early signaling defects, TIM-3 expression correlates with unresponsiveness of ex vivo CD8(+) T cells in FL. They show that scores based on the combination of exhaustion and cytolytic markers in FL microenvironment might be instrumental to identify patients at early risk of relapses following R-chemotherapy.

  12. Initial HIV-1 antigen-specific CD8+ T cells in acute HIV-1 infection inhibit transmitted/founder virus replication.

    PubMed

    Freel, Stephanie A; Picking, Ralph A; Ferrari, Guido; Ding, Haitao; Ochsenbauer, Christina; Kappes, John C; Kirchherr, Jennifer L; Soderberg, Kelly A; Weinhold, Kent J; Cunningham, Coleen K; Denny, Thomas N; Crump, John A; Cohen, Myron S; McMichael, Andrew J; Haynes, Barton F; Tomaras, Georgia D

    2012-06-01

    CD8-mediated virus inhibition can be detected in HIV-1-positive subjects who naturally control virus replication. Characterizing the inhibitory function of CD8(+) T cells during acute HIV-1 infection (AHI) can elucidate the nature of the CD8(+) responses that can be rapidly elicited and that contribute to virus control. We examined the timing and HIV-1 antigen specificity of antiviral CD8(+) T cells during AHI. Autologous and heterologous CD8(+) T cell antiviral functions were assessed longitudinally during AHI in five donors from the CHAVI 001 cohort using a CD8(+) T cell-mediated virus inhibition assay (CD8 VIA) and transmitted/founder (T/F) viruses. Potent CD8(+) antiviral responses against heterologous T/F viruses appeared during AHI at the first time point sampled in each of the 5 donors (Fiebig stages 1/2 to 5). Inhibition of an autologous T/F virus was durable to 48 weeks; however, inhibition of heterologous responses declined concurrent with the resolution of viremia. HIV-1 viruses from 6 months postinfection were more resistant to CD8(+)-mediated virus inhibition than cognate T/F viruses, demonstrating that the virus escapes early from CD8(+) T cell-mediated inhibition of virus replication. CD8(+) T cell antigen-specific subsets mediated inhibition of T/F virus replication via soluble components, and these soluble responses were stimulated by peptide pools that include epitopes that were shown to drive HIV-1 escape during AHI. These data provide insights into the mechanisms of CD8-mediated virus inhibition and suggest that functional analyses will be important for determining whether similar antigen-specific virus inhibition can be induced by T cell-directed vaccine strategies.

  13. CD8+ T Cells Specific to Apoptosis-Associated Antigens Predict the Response to Tumor Necrosis Factor Inhibitor Therapy in Rheumatoid Arthritis

    PubMed Central

    Citro, Alessandra; Scrivo, Rossana; Martini, Helene; Martire, Carmela; De Marzio, Paolo; Vestri, Anna Rita; Sidney, John; Sette, Alessandro; Barnaba, Vincenzo; Valesini, Guido

    2015-01-01

    CD8+ T cells specific to caspase-cleaved antigens derived from apoptotic T cells (apoptotic epitopes) represent a principal player in chronic immune activation, which is known to amplify immunopathology in various inflammatory diseases. The purpose of the present study was to investigate the relationship involving these autoreactive T cells, the rheumatoid arthritis immunopathology, and the response to tumor necrosis factor-α inhibitor therapy. The frequency of autoreactive CD8+ T cells specific to various apoptotic epitopes, as detected by both enzyme-linked immunospot assay and dextramers of major histocompatibility complex class I molecules complexed with relevant apoptotic epitopes, was longitudinally analyzed in the peripheral blood of rheumatoid arthritis patients who were submitted to etanercept treatment (or other tumor necrosis factor inhibitors as a control). The percentage of apoptotic epitope-specific CD8+ T cells was significantly higher in rheumatoid arthritis patients than in healthy donors, and correlated with the disease activity. More important, it was significantly more elevated in responders to tumor necrosis factor-α inhibitor therapy than in non-responders before the start of therapy; it significantly dropped only in the former following therapy. These data indicate that apoptotic epitope-specific CD8+ T cells may be involved in rheumatoid arthritis immunopathology through the production of inflammatory cytokines and that they may potentially represent a predictive biomarker of response to tumor necrosis factor-α inhibitor therapy to validate in a larger cohort of patients. PMID:26061065

  14. Immunization with a mimotope of GD2 ganglioside induces CD8+ T cells that recognize cell adhesion molecules on tumor cells.

    PubMed

    Wierzbicki, Andrzej; Gil, Margaret; Ciesielski, Michael; Fenstermaker, Robert A; Kaneko, Yutaro; Rokita, Hanna; Lau, Joseph T; Kozbor, Danuta

    2008-11-01

    The GD2 ganglioside expressed on neuroectodermal tumor cells has been used as a target for passive and active immunotherapy in patients with malignant melanoma and neuroblastoma. We have reported that immunization of mice with a 47-LDA mimotope of GD2, isolated from a phage display peptide library with anti-GD2 mAb 14G2a, induces MHC class I-restricted CD8(+) T cell responses to syngeneic neuroblastoma tumor cells. The cytotoxic activity of the vaccine-induced CTLs was independent of GD2 expression, suggesting recognition of a novel tumor-associated Ag cross-reacting with 47-LDA. Glycan microarray and immunoblotting studies using 14G2a mAb demonstrated that this Ab is highly specific for the entire carbohydrate motif of GD2 but also cross-reacts with a 105 kDa glycoprotein expressed by GD2(+) and GD2(-) neuroblastoma and melanoma cells. Functional studies of tumor cells grown in three-dimensional collagen cultures with 14G2a mAb showed decreases in matrix metalloproteinase-2 activation, a process regulated by the 105 kDa-activated leukocyte cell adhesion molecule (ALCAM/CD166). A recombinant CD166 glycoprotein was shown to be recognized by 14G2a Ab and inhibition of CD166 expression by RNA interference ablated the cell sensitivity to lysis by 47-LDA-induced CD8(+) T cells in vitro and in vivo. The binding of 14G2a to CD166 was not disruptable by a variety of exo- and endo-glycosidases, implying recognition of a non-glycan epitope on CD166. These results suggest that the vaccine-induced CTLs recognize a 47-LDA cross-reactive epitope expressed by CD166, and reveal a novel mechanism of induction of potent tumor-specific cellular responses by mimotopes of tumor-associated carbohydrate Ags.

  15. 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.

    PubMed

    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.

  16. Specific mutation of a gammaherpesvirus-expressed antigen in response to CD8 T cell selection in vivo.

    PubMed

    Loh, Joy; Popkin, Daniel L; Droit, Lindsay; Braaten, Douglas C; Zhao, Guoyan; Zhang, Xin; Vachharajani, Punit; Myers, Nancy; Hansen, Ted H; Virgin, Herbert W

    2012-03-01

    Herpesviruses are thought to be highly genetically stable, and their use as vaccine vectors has been proposed. However, studies of the human gammaherpesvirus, Epstein-Barr virus, have found viral isolates containing mutations in HLA class I-restricted epitopes. Using murine gammaherpesvirus 68 expressing ovalbumin (OVA), we examined the stability of a gammaherpesvirus antigenic locus under strong CD8 T cell selection in vivo. OVA-specific CD8 T cells selected viral isolates containing mutations in the OVA locus but minimal alterations in other genomic regions. Thus, a CD8 T cell response to a gammaherpesvirus-expressed antigen that is not essential for replication or pathogenesis can result in selective mutation of that antigen in vivo. This finding may have relevance for the use of herpesvirus vectors for chronic antigen expression in vivo.

  17. Comprehensive analysis of dengue virus-specific responses supports an HLA-linked protective role for CD8+ T cells.

    PubMed

    Weiskopf, Daniela; Angelo, Michael A; de Azeredo, Elzinandes L; Sidney, John; Greenbaum, Jason A; Fernando, Anira N; Broadwater, Anne; Kolla, Ravi V; De Silva, Aruna D; de Silva, Aravinda M; Mattia, Kimberly A; Doranz, Benjamin J; Grey, Howard M; Shresta, Sujan; Peters, Bjoern; Sette, Alessandro

    2013-05-28

    The role of CD8(+) T cells in dengue virus infection and subsequent disease manifestations is not fully understood. According to the original antigenic sin theory, skewing of T-cell responses induced by primary infection with one serotype causes less effective response upon secondary infection with a different serotype, predisposing individuals to severe disease. A comprehensive analysis of CD8(+) responses in the general population from the Sri Lankan hyperendemic area, involving the measurement of ex vivo IFNγ responses associated with more than 400 epitopes, challenges the original antigenic sin theory. Although skewing of responses toward primary infecting viruses was detected, this was not associated with impairment of responses either qualitatively or quantitatively. Furthermore, we demonstrate higher magnitude and more polyfunctional responses for HLA alleles associated with decreased susceptibility to severe disease, suggesting that a vigorous response by multifunctional CD8(+) T cells is associated with protection from dengue virus disease.

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

    PubMed Central

    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

  19. CD8+ T cells from HLA-B*57 elite suppressors effectively suppress replication of HIV-1 escape mutants

    PubMed Central

    2013-01-01

    Background Elite Controllers or Suppressors (ES) are HIV-1 positive individuals who maintain plasma viral loads below the limit of detection of standard clinical assays without antiretroviral therapy. Multiple lines of evidence suggest that the control of viral replication in these patients is due to a strong and specific cytotoxic T lymphocyte (CTL) response. The ability of CD8+ T cells to control HIV-1 replication is believed to be impaired by the development of escape mutations. Surprisingly, viruses amplified from the plasma of ES have been shown to contain multiple escape mutations, and it is not clear how immunologic control is maintained in the face of virologic escape. Results We investigated the effect of escape mutations within HLA*B-57-restricted Gag epitopes on the CD8+ T cell mediated suppression of HIV-1 replication. Using site directed mutagenesis, we constructed six NL4-3 based viruses with canonical escape mutations in one to three HLA*B-57-restricted Gag epitopes. Interestingly, similar levels of CTL-mediated suppression of replication in autologous primary CD4+ T cells were observed for all of the escape mutants. Intracellular cytokine staining was performed in order to determine the mechanisms involved in the suppression of the escape variants. While low baseline CD8+ T cells responses to wild type and escape variant peptides were seen, stimulation of PBMC with either wild type or escape variant peptides resulted in increased IFN-γ and perforin expression. Conclusions These data presented demonstrate that CD8+ T cells from ES are capable of suppressing replication of virus harboring escape mutations in HLA-B*57-restricted Gag epitopes. Additionally, our data suggest that ES CD8+ T cells are capable of generating effective de novo responses to escape mutants. PMID:24330837

  20. Active evasion of CTL mediated killing and low quality responding CD8+ T cells contribute to persistence of brucellosis.

    PubMed

    Durward, Marina; Radhakrishnan, Girish; Harms, Jerome; Bareiss, Claire; Magnani, Diogo; Splitter, Gary A

    2012-01-01

    Brucellosis is a common zoonotic disease that remains endemic in many parts of the world. Dissecting the host immune response during this disease provides insight as to why brucellosis is often difficult to resolve. We used a Brucella epitope specific in vivo killing assay to investigate the ability of CD8+ T cells to kill targets treated with purified pathogenic protein. Importantly, we found the pathogenic protein TcpB to be a novel effector of adaptive immune evasion by inhibiting CD8+ T cell killing of Brucella epitope specific target cells in mice. Further, BALB/c mice show active Brucella melitensis infection beyond one year, many with previously unreported focal infection of the urogenital area. A fraction of CD8+ T cells show a CD8+ Tmem phenotype of LFA-1hi, CD127hi, KLRG-1lo during the course of chronic brucellosis, while the CD8+ T cell pool as a whole had a very weak polyfunctional cytokine response with diminished co-expression of IFN-γ with TNFα and/or IL-2, a hallmark of exhaustion. When investigating the expression of these 3 cytokines individually, we observed significant IFN-γ expression at 90 and 180 days post-infection. TNFα expression did not significantly exceed or fall below background levels at any time. IL-2 expression did not significantly exceeded background, but, interestingly, did fall significantly below that of uninfected mice at 180 days post-infection. Brucella melitensis evades and blunts adaptive immunity during acute infection and our findings provide potential mechanisms for the deficit observed in responding CD8+ T cells during chronic brucellosis.

  1. Masked Selection: A Straightforward and Flexible Approach for the Selection of Binders Against Specific Epitopes and Differentially Expressed Proteins by Phage Display*

    PubMed Central

    Even-Desrumeaux, Klervi; Nevoltris, Damien; Lavaut, Marie Noelle; Alim, Karima; Borg, Jean-Paul; Audebert, Stéphane; Kerfelec, Brigitte; Baty, Daniel; Chames, Patrick

    2014-01-01

    Phage display is a well-established procedure to isolate binders against a wide variety of antigens that can be performed on purified antigens, but also on intact cells. As selection steps are performed in vitro, it is possible to focus the outcome of the selection on relevant epitopes by performing some additional steps, such as depletion or competitive elutions. However in practice, the efficiency of these steps is often limited and can lead to inconsistent results. We have designed a new selection method named masked selection, based on the blockade of unwanted epitopes to favor the targeting of relevant ones. We demonstrate the efficiency and flexibility of this method by selecting single-domain antibodies against a specific portion of a fusion protein, by selecting binders against several members of the seven transmembrane receptor family using transfected HEK cells, or by selecting binders against unknown breast cancer markers not expressed on normal samples. The relevance of this approach for antibody-based therapies was further validated by the identification of four of these markers, Epithelial cell adhesion molecule, Transferrin receptor 1, Metastasis cell adhesion molecule, and Sushi containing domain 2, using immunoprecipitation and mass spectrometry. This new phage display strategy can be applied to any type of antibody fragments or alternative scaffolds, and is especially suited for the rapid discovery and identification of cell surface markers. PMID:24361863

  2. Contribution of herpesvirus specific CD8 T cells to anti-viral T cell response in humans.

    PubMed

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

    2010-08-19

    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, 12 with Dengue, 12 with Influenza, 3 with Adenovirus infection and 3 with fevers of unknown etiology. Virus-specific (EBV, HCMV, Influenza) pentamer+ and total CD8 T cells were analyzed for activation (CD38/HLA-DR), proliferation (Ki-67/Bcl-2(low)) and cytokine production. We observed that all acute viral infections trigger an expansion of activated/proliferating CD8 T cells, which differs in size depending on the infection but is invariably inflated by CD8 T cells specific for persistent herpesviruses (HCMV/EBV). CD8 T cells specific for other non-related non persistent viral infection (i.e. Influenza) were not activated. IL-15, which is produced during acute viral infections, is the likely contributing mechanism driving the selective activation of herpesvirus specific CD8 T cells. In addition we were able to show that herpesvirus specific CD8 T cells displayed an increased ability to produce the anti-viral cytokine interferon-gamma during the acute phase of heterologous viral infection. Taken together, these data demonstrated that activated herpesvirus specific CD8 T cells inflate the activated/proliferating CD8 T cells population present during acute viral infections in human and can contribute to the heterologous anti-viral T cell response.

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

    SciTech Connect

    Ganusov, Vitaly V

    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

  4. Mosaic vaccines elicit CD8+ T lymphocyte responses that confer enhanced immune coverage of diverse HIV strains in monkeys.

    PubMed

    Santra, Sampa; Liao, Hua-Xin; Zhang, Ruijin; Muldoon, Mark; Watson, Sydeaka; Fischer, Will; Theiler, James; Szinger, James; Balachandran, Harikrishnan; Buzby, Adam; Quinn, David; Parks, Robert J; Tsao, Chun-Yen; Carville, Angela; Mansfield, Keith G; Pavlakis, George N; Felber, Barbara K; Haynes, Barton F; Korber, Bette T; Letvin, Norman L

    2010-03-01

    An effective HIV vaccine must elicit immune responses that recognize genetically diverse viruses. It must generate CD8+ T lymphocytes that control HIV replication and CD4+ T lymphocytes that provide help for the generation and maintenance of both cellular and humoral immune responses against the virus. Creating immunogens that can elicit cellular immune responses against the genetically varied circulating isolates of HIV presents a key challenge for creating an HIV vaccine. Polyvalent mosaic immunogens derived by in silico recombination of natural strains of HIV are designed to induce cellular immune responses that recognize genetically diverse circulating virus isolates. Here we immunized rhesus monkeys by plasmid DNA prime and recombinant vaccinia virus boost with vaccine constructs expressing either consensus or polyvalent mosaic proteins. As compared to consensus immunogens, the mosaic immunogens elicited CD8+ T lymphocyte responses to more epitopes of each viral protein than did the consensus immunogens and to more variant sequences of CD8+ T lymphocyte epitopes. This increased breadth and depth of epitope recognition may contribute both to protection against infection by genetically diverse viruses and to the control of variant viruses that emerge as they mutate away from recognition by cytotoxic T lymphocytes.

  5. Broadly targeted CD8+ T cell responses restricted by major histocompatibility complex E

    SciTech Connect

    Hansen, Scott G.; Wu, Helen L.; Burwits, Benjamin J.; Hughes, Colette M.; Hammond, Katherine B.; Ventura, Abigail B.; Reed, Jason S.; Gilbride, Roxanne M.; Ainslie, Emily; Morrow, David W.; Ford, Julia C.; Selseth, Andrea N.; Pathak, Reesab; Malouli, Daniel; Legasse, Alfred W.; Axthelm, Michael K.; Nelson, Jay A.; Gillespie, Geraldine M.; Walters, Lucy C.; Brackenridge, Simon; Sharpe, Hannah R.; Lopez, Cesar Augusto; Fruh, Klaus; Korber, Bette Tina; McMichael, Andrew J.; Gnanakaran, Sandrasegaram; Sacha, Jonah B.; Picker, Louis J.

    2016-02-12

    Major histocompatibility complex (MHC)-E is a highly conserved, ubiquitously expressed, nonclassical, MHC-Ib molecule with limited polymorphism primarily involved in regulation of NK cell reactivity via interaction with NKG2/CD94 receptors. We found that vaccination of rhesus macaques with Rh157.5/.4 gene-deleted rhesus Cytomegalovirus (RhCMV) vectors uniquely diverts MHC-E function to presentation of highly diverse peptide epitopes to CD8α/β+ T cells, approximately 4 distinct epitopes per 100 amino acids, in all tested protein antigens. Computational structural analysis revealed that a relatively stable, open binding groove in MHC-E attains broad peptide binding specificity by imposing a similar backbone configuration on bound peptides with few restrictions based on amino acid side chains. Since MHC-E is up-regulated on cells infected with HIV/SIV and other persistent viruses to evade NK cell activity, MHC-E-restricted CD8+ T cell responses have the potential to exploit pathogen immune evasion adaptations, a capability that might endow these unconventional responses with superior efficacy.

  6. Broadly targeted CD8+ T cell responses restricted by major histocompatibility complex E

    DOE PAGES

    Hansen, Scott G.; Wu, Helen L.; Burwits, Benjamin J.; ...

    2016-02-12

    Major histocompatibility complex (MHC)-E is a highly conserved, ubiquitously expressed, nonclassical, MHC-Ib molecule with limited polymorphism primarily involved in regulation of NK cell reactivity via interaction with NKG2/CD94 receptors. We found that vaccination of rhesus macaques with Rh157.5/.4 gene-deleted rhesus Cytomegalovirus (RhCMV) vectors uniquely diverts MHC-E function to presentation of highly diverse peptide epitopes to CD8α/β+ T cells, approximately 4 distinct epitopes per 100 amino acids, in all tested protein antigens. Computational structural analysis revealed that a relatively stable, open binding groove in MHC-E attains broad peptide binding specificity by imposing a similar backbone configuration on bound peptides with fewmore » restrictions based on amino acid side chains. Since MHC-E is up-regulated on cells infected with HIV/SIV and other persistent viruses to evade NK cell activity, MHC-E-restricted CD8+ T cell responses have the potential to exploit pathogen immune evasion adaptations, a capability that might endow these unconventional responses with superior efficacy.« less

  7. Defining CD8+ T cell determinants during human viral infection in populations of Asian ethnicity.

    PubMed

    Rivino, Laura; Tan, Anthony T; Chia, Adeline; Kumaran, Emmanuelle A P; Grotenbreg, Gijsbert M; MacAry, Paul A; Bertoletti, Antonio

    2013-10-15

    The identification of virus-specific CD8(+) T cell determinants is a fundamental requirement for our understanding of viral disease pathogenesis. T cell epitope mapping strategies increasingly rely on algorithms that predict the binding of peptides to MHC molecules. There is, however, little information on the reliability of predictive algorithms in the context of human populations, in particular, for those expressing HLA class I molecules for which there are limited experimental data available. In this study, we evaluate the ability of NetMHCpan to predict antiviral CD8(+) T cell epitopes that we identified with a traditional approach in patients of Asian ethnicity infected with Dengue virus, hepatitis B virus, or severe acute respiratory syndrome coronavirus. We experimentally demonstrate that the predictive power of algorithms defining peptide-MHC interaction directly correlates with the amount of training data on which the predictive algorithm has been constructed. These results highlight the limited applicability of the NetMHCpan algorithm for populations expressing HLA molecules for which there are little or no experimental binding data, such as those of Asian ethnicity.

  8. Contribution of TCR signaling strength to CD8+ T cell peripheral tolerance mechanisms.

    PubMed

    Smith, Trevor R F; Verdeil, Gregory; Marquardt, Kristi; Sherman, Linda A

    2014-10-01

    Peripheral tolerance mechanisms are in place to prevent T cells from mediating aberrant immune responses directed against self and environmental Ags. Mechanisms involved in the induction of peripheral tolerance include T cell-intrinsic pathways, such as anergy or deletion, or exogenous tolerance mediated by regulatory T cells. We have previously shown that the density of peptide-MHC class I recognized by the TCR determines whether CD8(+) T cells undergo anergy or deletion. Specifically, using a TCR-transgenic CD8(+) T cell model, we demonstrated that persistent peripheral exposure to low- or high-dose peptides in the absence of inflammatory signals resulted in clonal deletion or anergy of the T cell, respectively. In this study, by altering the affinity of the peptide-MHC tolerogen for TCR, we have confirmed that this mechanism is dependent on the level of TCR signaling that the CD8(+) T cell receives. Using altered peptide ligands (APLs) displaying high TCR affinities, we show that increasing the TCR signaling favors anergy induction. Conversely, using APLs displaying a decreased TCR affinity tilted our system in the direction of deletional tolerance. We demonstrate how differential peripheral CD8(+) T cell tolerance mechanisms are controlled by both the potency and density of MHC class I-peptide tolerogen.

  9. Heteroclitic Peptides Increase Proliferation and Reduce Evidence of Human Immunodeficiency Virus-Specific CD8⁺ T Cell Dysfunction.

    PubMed

    Adegoke, Adeolu; Gladney, Krista; Gallant, Maureen; Grant, Michael

    2015-10-01

    Human immunodeficiency virus (HIV)-specific CD8(+) T cell dysfunction parallels disease progression; therefore, restoring potent HIV-specific CD8(+) T cell responses is a key therapeutic goal. Certain CD8(+) T cell peptide epitope variants, termed heteroclitic, enhance cytokine production by the HIV-specific CD8(+) T cells of some individuals. In this study, we investigated whether heteroclitic peptides that enhance cytokine production by HIV-specific CD8(+) T cells also reduce functional and phenotypic evidence of HIV-specific CD8(+) T cell exhaustion in those instances. Twenty-four variant peptides of human histocompatibility-linked leukocyte antigen (HLA)-A2-restricted reference HIV peptide epitopes designated as A2-7; Nef 83→91, A2-8; Nef 135→143, A2-Gag; Gag 77→85 and A2-9; Gag 433→440 were synthesized with conservative and semiconservative amino acid substitutions at positions 3, 5, and 7 or 3, 5, and 8 of Gag 433→440. Variants that enhanced interferon-gamma (IFN-γ) and/or interleukin-2 (IL-2) production in enzyme-linked immunospot assays (29 cases overall) were subsequently tested by 7-day in vitro peptide stimulation for their effects on HIV-specific CD8(+) T cell proliferation and programmed death-1 (PD-1) expression. Heteroclitic variants enhanced HIV-specific CD8(+) T cell proliferation by >20% in 13/29 cases tested, reduced PD-1 expression on proliferating cells by 15-50% in 10 cases, and reduced PD-1 expression on proliferating cells by >50% in 3 cases. In five cases, the same heteroclitic peptide increased proliferation by >20% and reduced PD-1 expression by >15%. These data demonstrate that heteroclitic peptides can alter the magnitude and character of HIV-specific CD8(+) cell responses relative to reference peptides and may have a unique immunotherapeutic value in therapeutic vaccines.

  10. CD8+ T-Cell Responses in Hepatitis B and C: The (HLA-) A, B, and C of Hepatitis B and C.

    PubMed

    Nitschke, Katja; Luxenburger, Hendrik; Kiraithe, Muthamia M; Thimme, Robert; Neumann-Haefelin, Christoph

    Approximately 500 million people are chronically infected with the hepatitis B virus (HBV) or hepatitis C virus (HCV) worldwide and are thus at high risk of progressive liver disease, leading to liver fibrosis, cirrhosis and ultimately hepatocellular cancer. Virus-specific CD8+ T-cells play a major role in viral clearance in >90% of adult patients who clear HBV and in approximately 30% of patients who clear HCV in acute infection. However, several mechanisms contribute to the failure of the adaptive CD8+ T-cell response in those patients who progress to chronic infection. These include viral mutations leading to escape from the CD8+ T-cell response as well as exhaustion and dysfunction of virus-specific CD8+ T-cells. Antiviral efficacy of the virus-specific CD8+ T-cell response also strongly depends on its restriction by specific human leukocyte antigens (HLA) class I alleles. Our review will summarize the role of HLA-A, B and C-restricted CD8+ T-cells in HBV and HCV infection. Due to the current lack of a comprehensive database of HBV- and HCV-specific CD8+ T-cell epitopes, we also provide a summary of the repertoire of currently well-described HBV- and HCV-specific CD8+ T-cell epitopes. A better understanding of the factors that contribute to the success or failure of virus-specific CD8+ T-cells may help to develop new therapeutic options for HBV eradication in patients with chronic HBV infection (therapeutic vaccination and/or immunomodulation) as well as a prophylactic vaccine against HCV infection.

  11. Enhancing Human Immunodeficiency Virus-Specific CD8+ T Cell Responses with Heteroclitic Peptides

    PubMed Central

    Adegoke, Adeolu Oyemade; Grant, Michael David

    2015-01-01

    Human immunodeficiency virus (HIV)-specific CD8+ T cells play a critical role in containing HIV replication and delaying disease progression. However, HIV-specific CD8+ T cells become progressively more “exhausted” as chronic HIV infection proceeds. Symptoms of T cell exhaustion range from expression of inhibitory receptors and selective loss of cytokine production capacity through reduced proliferative potential, impaired differentiation into effector cells and increased susceptibility to apoptosis. While effective combination antiretroviral therapy (cART) durably reduces HIV viremia to undetectable levels, this alone does not restore the full pluripotency of HIV-specific CD8+ T cells. In a number of studies, a subset of peptide epitope variants categorized as heteroclitic, restimulated more potent cellular immune responses in vitro than did the native, immunizing peptides themselves. This property of heteroclitic peptides has been exploited in experimental cancer and chronic viral infection models to promote clearance of transformed cells and persistent viruses. In this review, we consider the possibility that heteroclitic peptides could improve the efficacy of therapeutic vaccines as part of HIV immunotherapy or eradication strategies. We review literature on heteroclitic peptides and illustrate their potential to beneficially modulate the nature of HIV-specific T cell responses toward those found in the small minority of HIV-infected, aviremic cART-naïve persons termed elite controllers or long-term non-progressors. Our review suggests that the efficacy of HIV vaccines could be improved by identification, testing, and incorporation of heteroclitic variants of native HIV peptide epitopes. PMID:26257743

  12. Lack of variant specific CD8+ T-cell response against mutant and pre-existing variants leads to outgrowth of particular clones in acute hepatitis C

    PubMed Central

    2013-01-01

    Background CTL escape mutations have been described during acute hepatitis C in patients who developed chronic disease later on. Our aim was to investigate the mutual relationship between HCV specific CD8+ T cells and evolution of the viral sequence during early acute HCV infection. Results We sequenced multiple clones of NS3 1406 epitope in 4 HLA-A*02 patients with acute hepatitis C genotype 1b infection. Pentamers specific for the variants were used to monitor the corresponding CD8+ T cell response. We observed outgrowth of mutations, which induced only a weak and thus potentially insufficient CD8+ T cell response. In one patient we observed outgrowth of variant epitopes with similarities to a different genotype rather than de novo mutations most probably due to a lack of responsiveness to these likely pre-existing variants. We could show that in acute hepatitis C CTL escape mutations occur much earlier than demonstrated in previous studies. Conclusions The adaption of the virus to a new host is characterized by a high and rapid variability in epitopes under CD8+ T cell immune pressure. This adaption takes place during the very early phase of acute infection and strikingly some sequences were reduced below the limit of detection at some time points but were detected at high frequency again at later time points. Independent of the observed variability, HCV-specific CD8+ T cell responses decline and no adaption to different or new antigens during the course of infection could be detected. PMID:24073713

  13. Self-specific CD8+ T cells maintain a semi-naive state following lymphopenia-induced proliferation.

    PubMed

    Johnson, Lisa D S; Jameson, Stephen C

    2010-05-15

    Upon transfer into T cell-deficient hosts, naive CD8(+) T cells typically undergo lymphopenia-induced proliferation (LIP, also called homeostatic proliferation) and develop the phenotypic and functional characteristics of memory CD8(+) T cells. However, the capacity of T cells with self-peptide/MHC specificity to respond in this way has not been intensively studied. We examined pmel-1 TCR transgenic CD8(+) T cells that are specific for an epitope from gp100, a protein expressed by melanoma cells and normal melanocytes. Despite their self-specificity, naive pmel-1 cells were inefficient at LIP in typical lymphopenic hosts. In CD132 (common gamma-chain)-deficient hosts, pmel-1 CD8(+) T cells underwent extensive proliferation, but, surprisingly, the majority of these cells retained certain naive phenotypic traits (CD44(low), CD122(low)) rather than acquiring the expected central-memory phenotype. Following LIP, pmel-1 T cells acquired the capacity to control B16F10 tumor growth, but only in common gamma-chain-deficient host mice. Together, these data suggest that LIP does not always favor expansion of self-specific CD8 T cells and that sustained extensive lymphopenia is required for such cells to exhibit tumor control.

  14. Prolonged antigen presentation by immune complex-binding dendritic cells programs the proliferative capacity of memory CD8 T cells.

    PubMed

    León, Beatriz; Ballesteros-Tato, André; Randall, Troy D; Lund, Frances E

    2014-07-28

    The commitment of naive CD8 T cells to effector or memory cell fates can occur after a single day of antigenic stimulation even though virus-derived antigens (Ags) are still presented by DCs long after acute infection is resolved. However, the effects of extended Ag presentation on CD8 T cells are undefined and the mechanisms that regulate prolonged Ag presentation are unknown. We showed that the sustained presentation of two different epitopes from influenza virus by DCs prevented the premature contraction of the primary virus-specific CD8 T cell response. Although prolonged Ag presentation did not alter the number of memory CD8 T cells that developed, it was essential for programming the capacity of these cells to proliferate, produce cytokines, and protect the host after secondary challenge. Importantly, prolonged Ag presentation by DCs was dependent on virus-specific, isotype-switched antibodies (Abs) that facilitated the capture and cross-presentation of viral Ags by FcγR-expressing DCs. Collectively, our results demonstrate that B cells and Abs can regulate the quality and functionality of a subset of antiviral CD8 T cell memory responses and do so by promoting sustained Ag presentation by DCs during the contraction phase of the primary T cell response.

  15. Phenotypical and functional evaluation of CD8+/S6F1+ T lymphocytes in haemophiliac individuals with HIV-1 infection.

    PubMed Central

    Cavallin, F; Traldi, A; Zambello, R

    1993-01-01

    In this study we investigated the distribution of the S6F1 antigen, an epitope of the lymphocyte function-associated antigen, on CD8+ T lymphocytes in a series of 15 HIV-1+ and 20 HIV-1- haemophiliac patients. MoAbs recognizing the S6F1 antigen have been claimed to distinguish between killer effectors (brightly S6F1+ stained) and suppressor cells (dimly S6F1+ stained) within the CD8+ lymphoid population. In addition, we tried to find a correlation between the spontaneous in vitro immunoglobulin synthesis from patients' peripheral blood lymphocytes and the pattern of S6F1 expression. Although the total number of double-positive CD8+/S6F1+ cells was similar in both HIV-1+ and HIV-1- haemophiliac patients, a significant increase in the CD8+/S6F1+ population bright versus dim was documented in HIV-1-infected with respect to HIV-1- haemophiliacs (bright/dim ratio 3.97 +/- 0.61 versus 0.75 +/- 0.1, respectively, P < 0.005). This finding was correlated to a significant increase in spontaneous in vitro immunoglobulin production in HIV-1+ subjects compared with control haemophiliacs (P < 0.005). Purified CD8+ lymphocytes from HIV-1+ subjects showed a reduced suppressor activity on mitogen-induced immunoglobulin production. Taken together, these data suggest that HIV-1 infection favours the generation of CD8+/S6F1+ bright cells with putative cytotoxic-associated function, leading to a progressive reduction in the number of CD8+/S6F1+ dim suppressor lymphocytes. This phenomenon may contribute to the polyclonal hypergammaglobulinaemia present in HIV-1+ haemophiliac patients. PMID:8324903

  16. A role for the histone H2A deubiquitinase MYSM1 in maintenance of CD8(+) T cells.

    PubMed

    Förster, Michael; Boora, Rupinder K; Petrov, Jessica C; Fodil, Nassima; Albanese, Isabella; Kim, Jamie; Gros, Philippe; Nijnik, Anastasia

    2017-05-01

    Several previous studies outlined the importance of the histone H2A deubiquitinase MYSM1 in the regulation of stem cell quiescence and haematopoiesis. In this study we investigated the role of MYSM1 in T-cell development. Using mouse models that allow conditional Mysm1 ablation at late stages of thymic development, we found that MYSM1 is intricately involved in the maintenance, activation and survival of CD8(+) T cells. Mysm1 ablation resulted in a twofold reduction in CD8(+) T-cell numbers, and also led to a hyperactivated CD8(+) T-cell state accompanied by impaired proliferation and increased pro-inflammatory cytokine production after ex vivo stimulation. These phenotypes coincided with an increased apoptosis and preferential up-regulation of p53 tumour suppressor protein in CD8(+) T cells. Lastly, we examined a model of experimental cerebral malaria, in which pathology is critically dependent on CD8(+) T cells. In the mice conditionally deleted for Mysm1 in the T-cell compartment, CD8(+) T-cell numbers remained reduced following infection, both in the periphery and in the brain, and the mice displayed improved survival after parasite challenge. Collectively, our data identify MYSM1 as a novel factor for CD8(+) T cells in the immune system, increasing our understanding of the role of histone H2A deubiquitinases in cytotoxic T-cell biology.

  17. Superior induction and maintenance of protective CD8 T cells in mice infected with mouse cytomegalovirus vector expressing RAE-1γ.

    PubMed

    Trsan, Tihana; Busche, Andreas; Abram, Maja; Wensveen, Felix M; Lemmermann, Niels A; Arapovic, Maja; Babic, Marina; Tomic, Adriana; Golemac, Mijo; Brinkmann, Melanie M; Jäger, Wiebke; Oxenius, Annette; Polic, Bojan; Krmpotic, Astrid; Messerle, Martin; Jonjic, Stipan

    2013-10-08

    Due to a unique pattern of CD8 T-cell response induced by cytomegaloviruses (CMVs), live attenuated CMVs are attractive candidates for vaccine vectors for a number of clinically relevant infections and tumors. NKG2D is one of the most important activating NK cell receptors that plays a role in costimulation of CD8 T cells. Here we demonstrate that the expression of CD8 T-cell epitope of Listeria monocytogenes by a recombinant mouse CMV (MCMV) expressing the NKG2D ligand retinoic acid early-inducible protein 1-gamma (RAE-1γ) dramatically enhanced the effectiveness and longevity of epitope-specific CD8 T-cell response and conferred protection against a subsequent challenge infection with Listeria monocytogenes. Unexpectedly, the attenuated growth in vivo of the CMV vector expressing RAE-1γ and its capacity to enhance specific CD8 T-cell response were preserved even in mice lacking NKG2D, implying additional immune function for RAE-1γ beyond engagement of NKG2D. Thus, vectors expressing RAE-1γ represent a promising approach in the development of CD8 T-cell-based vaccines.

  18. Superior induction and maintenance of protective CD8 T cells in mice infected with mouse cytomegalovirus vector expressing RAE-1γ

    PubMed Central

    Tršan, Tihana; Busche, Andreas; Abram, Maja; Wensveen, Felix M.; Lemmermann, Niels A.; Arapović, Maja; Babić, Marina; Tomić, Adriana; Golemac, Mijo; Brinkmann, Melanie M.; Jäger, Wiebke; Oxenius, Annette; Polić, Bojan; Krmpotić, Astrid; Messerle, Martin; Jonjić, Stipan

    2013-01-01

    Due to a unique pattern of CD8 T-cell response induced by cytomegaloviruses (CMVs), live attenuated CMVs are attractive candidates for vaccine vectors for a number of clinically relevant infections and tumors. NKG2D is one of the most important activating NK cell receptors that plays a role in costimulation of CD8 T cells. Here we demonstrate that the expression of CD8 T-cell epitope of Listeria monocytogenes by a recombinant mouse CMV (MCMV) expressing the NKG2D ligand retinoic acid early-inducible protein 1-gamma (RAE-1γ) dramatically enhanced the effectiveness and longevity of epitope-specific CD8 T-cell response and conferred protection against a subsequent challenge infection with Listeria monocytogenes. Unexpectedly, the attenuated growth in vivo of the CMV vector expressing RAE-1γ and its capacity to enhance specific CD8 T-cell response were preserved even in mice lacking NKG2D, implying additional immune function for RAE-1γ beyond engagement of NKG2D. Thus, vectors expressing RAE-1γ represent a promising approach in the development of CD8 T-cell–based vaccines. PMID:24052528

  19. Associations of HLA-A, HLA-B and HLA-C Alleles Frequency with Prevalence of Herpes Simplex Virus Infections and Diseases Across Global Populations: Implication for the Development of an Universal CD8+ T-Cell Epitope-Based Vaccine

    PubMed Central

    Samandary, Sarah; Kridane-Miledi, Hédia; Sandoval, Jacqueline S.; Choudhury, Zareen; Langa-Vives, Francina; Spencer, Doran; Chentoufi, Aziz A.; Lemonnier, François A.; BenMohamed, Lbachir

    2014-01-01

    A significant portion of the world’s population is infected with herpes simplex virus type 1 and/or type 2 (HSV-1 and/or HSV-2), that cause a wide range of diseases including genital herpes, oro-facial herpes, and the potentially blinding ocular herpes. While the global prevalence and distribution of HSV-1 and HSV-2 infections cannot be exactly established, the general trends indicate that: (i) HSV-1 infections are much more prevalent globally than HSV-2; (ii) Over half billion people worldwide are infected with HSV-2; (iii) the sub-Saharan African populations account for a disproportionate burden of genital herpes infections and diseases; (iv) the dramatic differences in the prevalence of herpes infections between regions of the world appear to be associated with differences in the frequencies of human leukocyte antigen (HLA) alleles. The present report: (i) analyzes the prevalence of HSV-1 and HSV-2 infections across various regions of the world; (ii) analyzes potential associations of common HLA-A, HLA-B and HLA-C alleles with the prevalence of HSV-1 and HSV-2 infections in the Caucasoid, Oriental, Hispanic and Black major populations; and (iii) discusses how our recently developed HLA-A, HLA-B, and HLA-C transgenic/H-2 class I null mice will help validate HLA/herpes prevalence associations. Overall, high prevalence of herpes infection and disease appears to be associated with high frequency of HLA-A*24, HLA-B*27, HLA-B*53 and HLA-B*58 alleles. In contrast, low prevalence of herpes infection and disease appears to be associated with high frequency of HLA-B*44 allele. The finding will aid in developing a T-cell epitope-based universal herpes vaccine and immunotherapy. PMID:24798939

  20. Associations of HLA-A, HLA-B and HLA-C alleles frequency with prevalence of herpes simplex virus infections and diseases across global populations: implication for the development of an universal CD8+ T-cell epitope-based vaccine.

    PubMed

    Samandary, Sarah; Kridane-Miledi, Hédia; Sandoval, Jacqueline S; Choudhury, Zareen; Langa-Vives, Francina; Spencer, Doran; Chentoufi, Aziz A; Lemonnier, François A; BenMohamed, Lbachir

    2014-08-01

    A significant portion of the world's population is infected with herpes simplex virus type 1 and/or type 2 (HSV-1 and/or HSV-2), that cause a wide range of diseases including genital herpes, oro-facial herpes, and the potentially blinding ocular herpes. While the global prevalence and distribution of HSV-1 and HSV-2 infections cannot be exactly established, the general trends indicate that: (i) HSV-1 infections are much more prevalent globally than HSV-2; (ii) over a half billion people worldwide are infected with HSV-2; (iii) the sub-Saharan African populations account for a disproportionate burden of genital herpes infections and diseases; (iv) the dramatic differences in the prevalence of herpes infections between regions of the world appear to be associated with differences in the frequencies of human leukocyte antigen (HLA) alleles. The present report: (i) analyzes the prevalence of HSV-1 and HSV-2 infections across various regions of the world; (ii) analyzes potential associations of common HLA-A, HLA-B and HLA-C alleles with the prevalence of HSV-1 and HSV-2 infections in the Caucasoid, Oriental, Hispanic and Black major populations; and (iii) discusses how our recently developed HLA-A, HLA-B, and HLA-C transgenic/H-2 class I null mice will help validate HLA/herpes prevalence associations. Overall, high prevalence of herpes infection and disease appears to be associated with high frequency of HLA-A(∗)24, HLA-B(∗)27, HLA-B(∗)53 and HLA-B(∗)58 alleles. In contrast, low prevalence of herpes infection and disease appears to be associated with high frequency of HLA-B(∗)44 allele. The finding will aid in developing a T-cell epitope-based universal herpes vaccine and immunotherapy.

  1. Discovering neutralizing antibodies targeting the stem epitope of H1N1 influenza hemagglutinin with synthetic phage-displayed antibody libraries.

    PubMed

    Tung, Chao-Ping; Chen, Ing-Chien; Yu, Chung-Ming; Peng, Hung-Pin; Jian, Jhih-Wei; Ma, Shiou-Hwa; Lee, Yu-Ching; Jan, Jia-Tsrong; Yang, An-Suei

    2015-10-12

    Broadly neutralizing antibodies developed from the IGHV1-69 germline gene are known to bind to the stem region of hemagglutinin in diverse influenza viruses but the sequence determinants for the antigen recognition, including neutralization potency and binding affinity, are not clearly understood. Such understanding could inform designs of synthetic antibody libraries targeting the stem epitope on hemagglutinin, leading to artificially designed antibodies that are functionally advantageous over antibodies from natural antibody repertoires. In this work, the sequence space of the complementarity determining regions of a broadly neutralizing antibody (F10) targeting the stem epitope on the hemagglutinin of a strain of H1N1 influenza virus was systematically explored; the elucidated antibody-hemagglutinin recognition principles were used to design a phage-displayed antibody library, which was then used to discover neutralizing antibodies against another strain of H1N1 virus. More than 1000 functional antibody candidates were selected from the antibody library and were shown to neutralize the corresponding strain of influenza virus with up to 7 folds higher potency comparing with the parent F10 antibody. The antibody library could be used to discover functionally effective antibodies against other H1N1 influenza viruses, supporting the notion that target-specific antibody libraries can be designed and constructed with systematic sequence-function information.

  2. A conformational epitope mapped in the bovine herpesvirus type 1 envelope glycoprotein B by phage display and the HSV-1 3D structure.

    PubMed

    Almeida, Greyciele R; Goulart, Luiz Ricardo; Cunha-Junior, Jair P; Bataus, Luiz A M; Japolla, Greice; Brito, Wilia M E D; Campos, Ivan T N; Ribeiro, Cristina; Souza, Guilherme R L

    2015-08-01

    The selected dodecapeptide (1)DRALYGPTVIDH(12) from a phage-displayed peptide library and the crystal structure of the envelope glycoprotein B (Env gB) from Herpes Simplex Virus type 1 (HSV-1) led us to the identification of a new discontinuous epitope on the Bovine herpesvirus type 1 (BoHV-1) Env gB. In silico analysis revealed a short BoHV-1 gB motif ((338)YKRD(341)) within a epitope region, with a high similarity to the motifs shared by the dodecapeptide N-terminal region ((5)YxARD(1)) and HSV-1 Env gB ((326)YARD(329)), in which the (328)Arg residue is described to be a neutralizing antibody target. Besides the characterization of an antibody-binding site of the BoHV-1 Env gB, we have demonstrated that the phage-fused peptide has the potential to be used as a reagent for virus diagnosis by phage-ELISA assay, which discriminated BoHV-1 infected serum samples from negative ones.

  3. Measles Virus Epitope Presentation by HLA: Novel Insights into Epitope Selection, Dominance, and Microvariation

    PubMed Central

    Schellens, Ingrid M.; Meiring, Hugo D.; Hoof, Ilka; Spijkers, Sanne N.; Poelen, Martien C. M.; van Gaans-van den Brink, Jacqueline A. M.; Costa, Ana I.; Vennema, Harry; Keşmir, Can; van Baarle, Debbie; van Els, Cécile A. C. M.

    2015-01-01

    Immunity to infections with measles virus (MV) can involve vigorous human leukocyte antigen (HLA) class I-restricted CD8+ cytotoxic T cell (CTL) responses. MV, albeit regarded monotypic, is known to undergo molecular evolution across its RNA genome. To address which regions of the MV proteome are eligible for recognition by CD8+ CTLs and how different HLA class I loci contribute to the epitope display, we interrogated the naturally processed and presented MV peptidome extracted from cell lines expressing in total a broad panel of 16 different common HLA-A, -B, and -C molecules. The repertoire and abundance of MV peptides were bona fide identified by nanoHPLC–MS/MS. ­Eighty-nine MV peptides were discovered and assignment to an HLA-A, -B, or -C allele, based on HLA-peptide affinity prediction, was in most cases successful. Length variation and presentation by multiple HLA class I molecules was common in the MV peptidome. More than twice as many unique MV epitopes were found to be restricted by HLA-B than by HLA-A, while MV peptides with supra-abundant expression rates (>5,000 cc) were rather associated with HLA-A and HLA-C. In total, 59 regions across the whole MV proteome were identified as targeted by HLA class I. Sequence coverage by epitopes was highest for internal proteins transcribed from the MV-P/V/C and -M genes and for hemagglutinin. At the genome level, the majority of the HLA class I-selected MV epitopes represented codons having a higher non-synonymous mutation rate than silent mutation rate, as established by comparison of a set of 58 unique full length MV genomes. Interestingly, more molecular variation was seen for the epitopes expressed at rates ≥1,000 cc. These data for the first time indicate that HLA class I broadly samples the MV proteome and that CTL pressure may contribute to the genomic evolution of MV. PMID:26579122

  4. Identification of a conserved JEV serocomplex B-cell epitope by screening a phage-display peptide library with a mAb generated against West Nile virus capsid protein

    PubMed Central

    2011-01-01

    Background The West Nile virus (WNV) capsid (C) protein is one of the three viral structural proteins, encapsidates the viral RNA to form the nucleocapsid, and is necessary for nuclear and nucleolar localization. The antigenic sites on C protein that are targeted by humoral immune responses have not been studied thoroughly, and well-defined B-cell epitopes on the WNV C protein have not been reported. Results In this study, we generated a WNV C protein-specific monoclonal antibody (mAb) and defined the linear epitope recognized by the mAb by screening a 12-mer peptide library using phage-display technology. The mAb, designated as 6D3, recognized the phages displaying a consensus motif consisting of the amino acid sequence KKPGGPG, which is identical to an amino acid sequence present in WNV C protein. Further fine mapping was conducted using truncated peptides expressed as MBP-fusion proteins. We found that the KKPGGPG motif is the minimal determinant of the linear epitope recognized by the mAb 6D3. Western blot (WB) analysis demonstrated that the KKPGGPG epitope could be recognized by antibodies contained in WNV- and Japanese encephalitis virus (JEV)-positive equine serum, but was not recognized by Dengue virus 1-4 (DENV1-4)-positive mice serum. Furthermore, we found that the epitope recognized by 6D3 is highly conserved among the JEV serocomplex of the Family Flaviviridae. Conclusion The KKPGGPG epitope is a JEV serocomplex-specific linear B-cell epitope recognized by the 6D3 mAb generated in this study. The 6D3 mAb may serve as a novel reagent in development of diagnostic tests for JEV serocomplex infection. Further, the identification of the B-cell epitope that is highly conserved among the JEV serocomplex may support the rationale design of vaccines against viruses of the JEV serocomplex. PMID:21375771

  5. Heightened self-reactivity associated with selective survival, but not expansion, of naïve virus-specific CD8+ T cells in aged mice

    PubMed Central

    Quinn, Kylie M.; Zaloumis, Sophie G.; Cukalac, Tania; Kan, Wan-Ting; Sng, Xavier Y. X.; Mirams, Michiko; Watson, Katherine A.; Doherty, Peter C.; Thomas, Paul G.; Handel, Andreas; La Gruta, Nicole L.

    2016-01-01

    In advanced age, decreased CD8+ cytotoxic T-lymphocyte (CTL) responses to novel pathogens and cancer is paralleled by a decline in the number and function of naïve CTL precursors (CTLp). Although the age-related fall in CD8+ T-cell numbers is well established, neither the underlying mechanisms nor the extent of variation for different epitope specificities have been defined. Furthermore, naïve CD8+ T cells expressing high levels of CD44 accumulate with age, but it is unknown whether this accumulation reflects their preferential survival or an age-dependent driver of CD8+ T-cell proliferation. Here, we track the number and phenotype of four influenza A virus (IAV)-specific CTLp populations in naïve C57BL/6 (B6) mice during aging, and compare T-cell receptor (TCR) clonal diversity for the CD44hi and CD44lo subsets of one such population. We show differential onset of decline for several IAV-specific CD8+ T-cell populations with advanced age that parallel age-associated changes in the B6 immunodominance hierarchy, suggestive of distinct impacts of aging on different epitope-specific populations. Despite finding no evidence of clonal expansions in an aged, epitope-specific TCR repertoire, nonrandom alterations in TCR usage were observed, along with elevated CD5 and CD8 coreceptor expression. Collectively, these data demonstrate that naïve CD8+ T cells expressing markers of heightened self-recognition are selectively retained, but not clonally expanded, during aging. PMID:26787864

  6. RSV-specific airway resident memory CD8+ T cells and differential disease severity after experimental human infection.

    PubMed

    Jozwik, Agnieszka; Habibi, Maximillian S; Paras, Allan; Zhu, Jie; Guvenel, Aleks; Dhariwal, Jaideep; Almond, Mark; Wong, Ernie H C; Sykes, Annemarie; Maybeno, Matthew; Del Rosario, Jerico; Trujillo-Torralbo, Maria-Belen; Mallia, Patrick; Sidney, John; Peters, Bjoern; Kon, Onn Min; Sette, Alessandro; Johnston, Sebastian L; Openshaw, Peter J; Chiu, Christopher

    2015-12-21

    In animal models, resident memory CD8+ T (Trm) cells assist in respiratory virus elimination but their importance in man has not been determined. Here, using experimental human respiratory syncytial virus (RSV) infection, we investigate systemic and local virus-specific CD8+ T-cell responses in adult volunteers. Having defined the immunodominance hierarchy, we analyse phenotype and function longitudinally in blood and by serial bronchoscopy. Despite rapid clinical recovery, we note surprisingly extensive lower airway inflammation with persistent viral antigen and cellular infiltrates. Pulmonary virus-specific CD8+ T cells display a CD69+CD103+ Trm phenotype and accumulate to strikingly high frequencies into convalescence without continued proliferation. While these have a more highly differentiated phenotype, they express fewer cytotoxicity markers than in blood. Nevertheless, their abundance before infection correlates with reduced symptoms and viral load, implying that CD8+ Trm cells in the human lung can confer protection against severe respiratory viral disease when humoral immunity is overcome.

  7. An inducible transgenic mouse breast cancer model for the analysis of tumor antigen specific CD8+ T-cell responses

    PubMed Central

    Bruns, Michael; Wanger, Jara; Utermöhlen, Olaf; Deppert, Wolfgang

    2015-01-01

    In Simian virus 40 (SV40) transgenic BALB/c WAP-T mice tumor development and progression is driven by SV40 tumor antigens encoded by inducible transgenes. WAP-T mice constitute a well characterized mouse model for breast cancer with strong similarities to the corresponding human disease. BALB/c mice mount only a weak cellular immune response against SV40 T-antigen (T-Ag). For studying tumor antigen specific CD8+ T-cell responses against transgene expressing cells, we created WAP-TNP mice, in which the transgene additionally codes for the NP118–126-epitope contained within the nucleoprotein of lymphocytic choriomeningitis virus (LCMV), the immune-dominant T-cell epitope in BALB/c mice. We then investigated in WAP-TNP mice the immune responses against SV40 tumor antigens and the NP-epitope within the chimeric T-Ag/NP protein (T-AgNP). Analysis of the immune-reactivity against T-Ag in WAP-T and of T-AgNP in WAP-TNP mice revealed that, in contrast to wild type (wt) BALB/c mice, WAP-T and WAP-TNP mice were non-reactive against T-Ag. However, like wtBALB/c mice, WAP-T as well as WAP-TNP mice were highly reactive against the immune-dominant LCMV NP-epitope, thereby allowing the analysis of NP-epitope specific cellular immune responses in WAP-TNP mice. LCMV infection of WAP-TNP mice induced a strong, LCMV NP-epitope specific CD8+ T-cell response, which was able to specifically eliminate T-AgNP expressing mammary epithelial cells both prior to tumor formation (i.e. in cells of lactating mammary glands), as well as in invasive tumors. Elimination of tumor cells, however, was only transient, even after repeated LCMV infections. Further studies showed that already non-infected WAP-TNP tumor mice contained LCMV NP-epitope specific CD8+ T-cells, albeit with strongly reduced, though measurable activity. Functional impairment of these ‘endogenous’ NP-epitope specific T-cells seems to be caused by expression of the programmed death-1 protein (PD1), as anti-PD1 treatment of

  8. Imaging CD8+ T cells during diverse viral infections

    PubMed Central

    Hickman, Heather D

    2015-01-01

    CD8+ T cells play a critical role in host defense against pathogens and tumors. Much of our current knowledge of the activation and subsequent effector activities of CD8+ T cells has been gained using ex vivo approaches examining the T cell population en masse for surface phenotype, activation status and the production of effector molecules. Thus, the precise behaviors and diversity of individual CD8+ T cells responding to virus infection in vivo have not been extensively explored, leaving many unanswered questions relevant to the rational design of antiviral vaccines and therapeutics. Recently, intravital multiphoton microscopy (MPM) has been used to image CD8+ T cell priming after infection with disparate viral pathogens ranging from small RNA viruses encoding few proteins to DNA viruses producing hundreds of viral proteins (many immunomodulatory). After priming, effector CD8+ T cells have been visualized in virus-infected tissue, both during primary infection and after transitioning to tissue resident memory cells (TRM). Here, I highlight recent advances in our understanding of antiviral CD8+ T cell responses revealed through intravital MPM. PMID:28243513

  9. CD39 Expression Identifies Terminally Exhausted CD8+ T Cells.

    PubMed

    Gupta, Prakash K; Godec, Jernej; Wolski, David; Adland, Emily; Yates, Kathleen; Pauken, Kristen E; Cosgrove, Cormac; Ledderose, Carola; Junger, Wolfgang G; Robson, Simon C; Wherry, E John; Alter, Galit; Goulder, Philip J R; Klenerman, Paul; Sharpe, Arlene H; Lauer, Georg M; Haining, W Nicholas

    2015-10-01

    Exhausted T cells express multiple co-inhibitory molecules that impair their function and limit immunity to chronic viral infection. Defining novel markers of exhaustion is important both for identifying and potentially reversing T cell exhaustion. Herein, we show that the ectonucleotidse CD39 is a marker of exhausted CD8+ T cells. CD8+ T cells specific for HCV or HIV express high levels of CD39, but those specific for EBV and CMV do not. CD39 expressed by CD8+ T cells in chronic infection is enzymatically active, co-expressed with PD-1, marks cells with a transcriptional signature of T cell exhaustion and correlates with viral load in HIV and HCV. In the mouse model of chronic Lymphocytic Choriomeningitis Virus infection, virus-specific CD8+ T cells contain a population of CD39high CD8+ T cells that is absent in functional memory cells elicited by acute infection. This CD39high CD8+ T cell population is enriched for cells with the phenotypic and functional profile of terminal exhaustion. These findings provide a new marker of T cell exhaustion, and implicate the purinergic pathway in the regulation of T cell exhaustion.

  10. NADPH oxidase deficiency underlies dysfunction of aged CD8+ Tregs

    PubMed Central

    Wen, Zhenke; Shimojima, Yasuhiro; Shirai, Tsuyoshi; Li, Yinyin; Ju, Jihang; Yang, Zhen; Tian, Lu; Goronzy, Jörg J.

    2016-01-01

    Immune aging results in progressive loss of both protective immunity and T cell–mediated suppression, thereby conferring susceptibility to a combination of immunodeficiency and chronic inflammatory disease. Here, we determined that older individuals fail to generate immunosuppressive CD8+CCR7+ Tregs, a defect that is even more pronounced in the age-related vasculitic syndrome giant cell arteritis. In young, healthy individuals, CD8+CCR7+ Tregs are localized in T cell zones of secondary lymphoid organs, suppress activation and expansion of CD4 T cells by inhibiting the phosphorylation of membrane-proximal signaling molecules, and effectively inhibit proliferative expansion of CD4 T cells in vitro and in vivo. We identified deficiency of NADPH oxidase 2 (NOX2) as the molecular underpinning of CD8 Treg failure in the older individuals and in patients with giant cell arteritis. CD8 Tregs suppress by releasing exosomes that carry preassembled NOX2 membrane clusters and are taken up by CD4 T cells. Overexpression of NOX2 in aged CD8 Tregs promptly restored suppressive function. Together, our data support NOX2 as a critical component of the suppressive machinery of CD8 Tregs and suggest that repairing NOX2 deficiency in these cells may protect older individuals from tissue-destructive inflammatory disease, such as large-vessel vasculitis. PMID:27088800

  11. Simian immunodeficiency virus infection of CD8+ lymphocytes in vivo.

    PubMed Central

    Dean, G A; Reubel, G H; Pedersen, N C

    1996-01-01

    To determine the lymphoid target cells of simian immunodeficiency virus (SIV) in vivo, peripheral blood lymphocytes (PBL) and lymph node lymphocytes (LNL) were positively selected (>97% purity) for surface expression of CD4, CD8, or CD20 and then analyzed for SIV provirus using semiquantitative DNA amplification. We found provirus in CD4+ and CD8+ lymphocytes but none in CD20+ lymphocytes. During acute SIV infection (< or = 214 days postinoculation), the percentage of PBL and LNL CD4+ cells containing proviral DNA ranged from 0.2 to 20% and from 0.2 to 2%, respectively. Proviral burden in the CD8+ population of either PBL or LNL ranged from 0.01 to 0.2%. Virus isolation by cocultivation was positive for both CD4+ and CD8+ purified populations. No difference in proviral burden was observed between PBL and LNL subsets during acute SIV infection. Up to 19.4% of positively selected CD8+ cells also expressed CD4, and thus the provirus may reside within a dual-positive population. This dual-positive population may represent activated lymphocytes that are particularly susceptible to infection and may provide an opportunity for virus entry into the CD8+ CD4- lymphocytes in vivo. PMID:8764081

  12. CD8(+) T cell-mediated immunity during Trypanosoma cruzi infection: a path for vaccine development?

    PubMed

    Dos Santos Virgilio, Fernando; Pontes, Camila; Dominguez, Mariana Ribeiro; Ersching, Jonatan; Rodrigues, Mauricio Martins; Vasconcelos, José Ronnie

    2014-01-01

    MHC-restricted CD8(+) T cells are important during infection with the intracellular protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. Experimental studies performed in the past 25 years have elucidated a number of features related to the immune response mediated by these T cells, which are important for establishing the parasite/host equilibrium leading to chronic infection. CD8(+) T cells are specific for highly immunodominant antigens expressed by members of the trans-sialidase family. After infection, their activation is delayed, and the cells display a high proliferative activity associated with high apoptotic rates. Although they participate in parasite control and elimination, they are unable to clear the infection due to their low fitness, allowing the parasite to establish the chronic phase when these cells then play an active role in the induction of heart immunopathology. Vaccination with a number of subunit recombinant vaccines aimed at eliciting specific CD8(+) T cells can reverse this path, thereby generating a productive immune response that will lead to the control of infection, reduction of symptoms, and reduction of disease transmission. Due to these attributes, activation of CD8(+) T lymphocytes may constitute a path for the development of a veterinarian or human vaccine.

  13. CD8+ T Cell-Mediated Immunity during Trypanosoma cruzi Infection: A Path for Vaccine Development?

    PubMed Central

    dos Santos Virgilio, Fernando; Pontes, Camila; Dominguez, Mariana Ribeiro; Ersching, Jonatan; Rodrigues, Mauricio Martins; Vasconcelos, José Ronnie

    2014-01-01

    MHC-restricted CD8+ T cells are important during infection with the intracellular protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. Experimental studies performed in the past 25 years have elucidated a number of features related to the immune response mediated by these T cells, which are important for establishing the parasite/host equilibrium leading to chronic infection. CD8+ T cells are specific for highly immunodominant antigens expressed by members of the trans-sialidase family. After infection, their activation is delayed, and the cells display a high proliferative activity associated with high apoptotic rates. Although they participate in parasite control and elimination, they are unable to clear the infection due to their low fitness, allowing the parasite to establish the chronic phase when these cells then play an active role in the induction of heart immunopathology. Vaccination with a number of subunit recombinant vaccines aimed at eliciting specific CD8+ T cells can reverse this path, thereby generating a productive immune response that will lead to the control of infection, reduction of symptoms, and reduction of disease transmission. Due to these attributes, activation of CD8+ T lymphocytes may constitute a path for the development of a veterinarian or human vaccine. PMID:25104879

  14. Tumor antigen-specific CD8(+) T cells are negatively regulated by PD-1 and Tim-3 in human gastric cancer.

    PubMed

    Lu, Xu; Yang, Lin; Yao, Daxing; Wu, Xuan; Li, Jingpo; Liu, Xuesong; Deng, Lijuan; Huang, Caiting; Wang, Yue; Li, Dan; Liu, Jingwei

    2017-03-01

    Cytotoxic CD8 T lymphocytes that are present in tumors and capable of recognizing tumor epitopes are nevertheless generally important in eliciting tumor rejection. NY-ESO-1 is a major target of CD8(+) T cell recognition in gastric cancer (GC) and is among the most immunogenic tumor antigens defined to date. Thus, identifying the immune escape mechanisms responsible for inducing tumor-specific CD8(+) T cell dysfunction may reveal effective strategies for immunotherapy. In an effort to understand in vivo tolerance mechanisms, we assessed the phenotype and function of NY-ESO-1-specific CD8(+) T cells derived from peripheral blood lymphocytes (PBLs) and tumor-associated lymphocytes (TALs) of GC patients. Here, we report that Tim-3 expression defines a subpopulation of PD-1(+) exhausted NY-ESO-1-specific CD8(+) T cell and PD-1(+)Tim-3(+) CD8(+) T cells represented the largest subset of NY-ESO-1-specific CD8(+) T cells in GC patients. Functionally, CD8(+)PD-1(+)Tim-3(+) T cells were more impaired in IFN-γ, TNF-α and IL-2 production compared with PD-1(+)Tim-3(-) or PD-1(-)Tim-3(-) subsets. Dual blockade of Tim-3 and PD-1 during T-cell priming efficiently augmented proliferation and cytokine production by NY-ESO-1-specific CD8(+) T cells could potentially be improved by therapeutic targeting of these inhibitory receptors, indicating that antitumor function of NY-ESO-1-specific CD8(+) T cells could potentially be improved by therapeutic targeting of these inhibitory receptors.

  15. Protective Role of Cross-Reactive CD8 T Cells Against Dengue Virus Infection.

    PubMed

    Elong Ngono, Annie; Chen, Hui-Wen; Tang, William W; Joo, Yunichel; King, Kevin; Weiskopf, Daniela; Sidney, John; Sette, Alessandro; Shresta, Sujan

    2016-11-01

    Infection with one of the four dengue virus serotypes (DENV1-4) presumably leads to lifelong immunity against the infecting serotype but not against heterotypic reinfection, resulting in a greater risk of developing Dengue Hemorrhagic Fever/Dengue Shock Syndrome (DHF/DSS) during secondary infection. Both antibodies and T cell responses have been implicated in DHF/DSS pathogenesis. According to the T cell-based hypothesis termed "original antigenic sin," secondary DENV infection is dominated by non-protective, cross-reactive T cells that elicit an aberrant immune response. The goal of our study was to compare the roles of serotype-specific and cross-reactive T cells in protection vs. pathogenesis during DENV infection in vivo. Specifically, we utilized IFN-α/βR(-/-) HLA*B0702 transgenic mice in the context of peptide vaccination with relevant human CD8 T cell epitopes. IFN-α/βR(-/-) HLA*B0702 transgenic mice were immunized with DENV serotype 2 (DENV2)-specific epitopes or variants found in any of the other three serotypes (DENV1, DENV3 or DENV4), followed by challenge with DENV. Although cross-reactive T cell responses were lower than responses elicited by serotype-specific T cells, immunization with either serotype-specific or variant peptide epitopes enhanced viral clearance, demonstrating that both serotype-specific and cross-reactive T cells can contribute to protection in vivo against DENV infection.

  16. Protective Efficacy of Individual CD8+ T Cell Specificities in Chronic Viral Infection §§

    PubMed Central

    Johnson, Susan; Bergthaler, Andreas; Graw, Frederik; Flatz, Lukas; Bonilla, Weldy V.; Siegrist, Claire-Anne; Lambert, Paul-Henri; Regoes, Roland R.; Pinschewer, Daniel D.

    2014-01-01

    Specific CD8+ T cells (CTLs) play an important role in resolving protracted infection with hepatitis B and C virus in humans and lymphocytic choriomeningitis virus (LCMV) in mice. The contribution of individual CTL specificities to chronic virus control, as well as epitope-specific patterns in timing and persistence of antiviral selection pressure remain, however, incompletely defined. To monitor and characterize the antiviral efficacy of individual CTL specificities throughout the course of chronic infection, we co-inoculated mice with a mixture of wildtype LCMV and genetically engineered CTL epitope-deficient mutant virus. A quantitative longitudinal assessment of viral competition revealed that mice continuously exerted CTL selection pressure on the persisting virus population. The timing of selection pressure characterized individual epitope specificities, and its magnitude varied considerably between individual mice. This longitudinal assessment of “antiviral efficacy” provides a novel parameter to characterize CTL responses in chronic viral infection. It demonstrates remarkable perseverance of all antiviral CTL specificities studied, thus raising hope for therapeutic vaccination in the treatment of persistent viral diseases. PMID:25567678

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

    PubMed Central

    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

  18. Collapse of Cytolytic Potential in SIV-Specific CD8+ T Cells Following Acute SIV Infection in Rhesus Macaques

    PubMed Central

    Roberts, Emily R.; Carnathan, Diane G.; Li, Hui; Shaw, George M.; Silvestri, Guido

    2016-01-01

    Poor maintenance of cytotoxic factor expression among HIV-specific CD8+ T cells, in part caused by dysregulated expression of the transcription factor T-bet, is associated with HIV disease progression. However, the precise evolution and context in which CD8+ T cell cytotoxic functions become dysregulated in HIV infection remain unclear. Using the rhesus macaque (RM) SIV infection model, we evaluated the kinetics of SIV-specific CD8+ T cell cytolytic factor expression in peripheral blood, lymph node, spleen, and gut mucosa from early acute infection through chronic infection. We identified rapid acquisition of perforin and granzyme B expression in SIV-specific CD8+ T cells in blood, secondary lymphoid tissues and gut mucosa that collapsed rapidly during the transition to chronic infection. The evolution of this expression profile was linked to low expression of T-bet and occurred independent of epitope specificity, viral escape patterns and tissue origin. Importantly, during acute infection SIV-specific CD8+ T cells that maintained T-bet expression retained the ability to express granzyme B after stimulation, but this relationship was lost in chronic infection. Together, these data demonstrate the loss of cytolytic machinery in SIV-specific CD8+ T cells in blood and at tissue sites of viral reservoir and active replication during the transition from acute to chronic infection. This phenomenon occurs despite persistent high levels of viremia suggesting that an inability to maintain properly regulated cytotoxic T cell responses in all tissue sites enables HIV/SIV to avoid immune clearance, establish persistent viral reservoirs in lymphoid tissues and gut mucosa, and lead ultimately to immunopathogenesis and death. PMID:28036372

  19. Peripheral self-reactivity regulates antigen-specific CD8 T-cell responses and cell division under physiological conditions

    PubMed Central

    Swee, Lee Kim; Tan, Zhen Wei; Sanecka, Anna; Yoshida, Nagisa; Patel, Harshil; Grotenbreg, Gijsbert; Ploegh, Hidde L.

    2016-01-01

    T-cell identity is established by the expression of a clonotypic T-cell receptor (TCR), generated by somatic rearrangement of TCRα and β genes. The properties of the TCR determine both the degree of self-reactivity and the repertoire of antigens that can be recognized. For CD8 T cells, the relationship between TCR identity—hence reactivity to self—and effector function(s) remains to be fully understood and has rarely been explored outside of the H-2b haplotype. We measured the affinity of three structurally distinct CD8 T-cell-derived TCRs that recognize the identical H-2 Ld-restricted epitope, derived from the Rop7 protein of Toxoplasma gondii. We used CD8 T cells obtained from mice generated by somatic cell nuclear transfer as the closest approximation of primary T cells with physiological TCR rearrangements and TCR expression levels. First, we demonstrate the common occurrence of secondary rearrangements in endogenously rearranged loci. Furthermore, we characterized and compared the response of Rop7-specific CD8 T-cell clones upon Toxoplasma gondii infection as well as effector function and TCR signalling upon antigenic stimulation in vitro. Antigen-independent TCR cross-linking in vitro uncovered profound intrinsic differences in the effector functions between T-cell clones. Finally, by assessing the degree of self-reactivity and comparing the transcriptomes of naive Rop7 CD8 T cells, we show that lower self-reactivity correlates with lower effector capacity, whereas higher self-reactivity is associated with enhanced effector function as well as cell cycle entry under physiological conditions. Altogether, our data show that potential effector functions and basal proliferation of CD8 T cells are set by self-reactivity thresholds. PMID:27881740

  20. Proteasomes generate spliced epitopes by two different mechanisms and as efficiently as non-spliced epitopes

    PubMed Central

    Ebstein, F.; Textoris-Taube, K.; Keller, C.; Golnik, R.; Vigneron, N.; Van den Eynde, B. J.; Schuler-Thurner, B.; Schadendorf, D.; Lorenz, F. K. M.; Uckert, W.; Urban, S.; Lehmann, A.; Albrecht-Koepke, N.; Janek, K.; Henklein, P.; Niewienda, A.; Kloetzel, P. M.; Mishto, M.

    2016-01-01

    Proteasome-catalyzed peptide splicing represents an additional catalytic activity of proteasomes contributing to the pool of MHC-class I-presented epitopes. We here biochemically and functionally characterized a new melanoma gp100 derived spliced epitope. We demonstrate that the gp100mel47–52/40–42 antigenic peptide is generated in vitro and in cellulo by a not yet described proteasomal condensation reaction. gp100mel47–52/40–42 generation is enhanced in the presence of the β5i/LMP7 proteasome-subunit and elicits a peptide-specific CD8+ T cell response. Importantly, we demonstrate that different gp100mel-derived spliced epitopes are generated and presented to CD8+ T cells with efficacies comparable to non-spliced canonical tumor epitopes and that gp100mel-derived spliced epitopes trigger activation of CD8+ T cells found in peripheral blood of half of the melanoma patients tested. Our data suggest that both transpeptidation and condensation reactions contribute to the frequent generation of spliced epitopes also in vivo and that their immune relevance may be comparable to non-spliced epitopes. PMID:27049119

  1. Identification of protective Lassa virus epitopes that are restricted by HLA-A2.

    PubMed

    Botten, Jason; Alexander, Jeff; Pasquetto, Valerie; Sidney, John; Barrowman, Polly; Ting, Joey; Peters, Bjoern; Southwood, Scott; Stewart, Barbara; Rodriguez-Carreno, Maria P; Mothe, Bianca; Whitton, J Lindsay; Sette, Alessandro; Buchmeier, Michael J

    2006-09-01

    Recovery from Lassa virus (LASV) infection usually precedes the appearance of neutralizing antibodies, indicating that cellular immunity plays a primary role in viral clearance. To date, the role of LASV-specific CD8(+) T cells has not been evaluated in humans. To facilitate such studies, we utilized a predictive algorithm to identify candidate HLA-A2 supertype epitopes from the LASV nucleoprotein and glycoprotein precursor (GPC) genes. We identified three peptides (GPC(42-50), GLVGLVTFL; GPC(60-68), SLYKGVYEL; and GPC(441-449), YLISIFLHL) that displayed high-affinity binding (< or =98 nM) to HLA-A*0201, induced CD8(+) T-cell responses of high functional avidity in HLA-A*0201 transgenic mice, and were naturally processed from native LASV GPC in human HLA-A*0201-positive target cells. HLA-A*0201 mice immunized with either GPC(42-50) or GPC(60-68) were protected against challenge with a recombinant vaccinia virus that expressed LASV GPC. The epitopes identified in this study represent potential diagnostic reagents and candidates for inclusion in epitope-based vaccine constructs. Our approach is applicable to any pathogen with existing sequence data, does not require manipulation of the actual pathogen or access to immune human donors, and should therefore be generally applicable to category A through C agents and other emerging pathogens.

  2. Functional heterogeneity of human effector CD8+ T cells.

    PubMed

    Takata, Hiroshi; Naruto, Takuya; Takiguchi, Masafumi

    2012-02-09

    Effector CD8(+) T cells are believed to be terminally differentiated cells having cytotoxic activity and the ability to produce effector cytokines such as INF-γ and TNF-α. We investigated the difference between CXCR1(+) and CXCR1(-) subsets of human effector CD27(-)CD28(-)CD8(+) T cells. The subsets expressed cytolytic molecules similarly and exerted substantial cytolytic activity, whereas only the CXCR1(-) subset had IL-2 productivity and self-proliferative activity and was more resistant to cell death than the CXCR1(+) subset. These differences were explained by the specific up-regulation of CAMK4, SPRY2, and IL-7R in the CXCR1(-) subset and that of pro-apoptotic death-associated protein kinase 1 (DAPK1) in the CXCR1(+) subset. The IL-2 producers were more frequently found in the IL-7R(+) subset of the CXCR1(-) effector CD8(+) T cells than in the IL-7R(-) subset. IL-7/IL-7R signaling promoted cell survival only in the CXCR1(-) subset. The present study has highlighted a novel subset of effector CD8(+) T cells producing IL-2 and suggests the importance of this subset in the homeostasis of effector CD8(+) T cells.

  3. Immune signatures of protective spleen memory CD8 T cells

    PubMed Central

    Brinza, Lilia; Djebali, Sophia; Tomkowiak, Martine; Mafille, Julien; Loiseau, Céline; Jouve, Pierre-Emmanuel; de Bernard, Simon; Buffat, Laurent; Lina, Bruno; Ottmann, Michèle; Rosa-Calatrava, Manuel; Schicklin, Stéphane; Bonnefoy, Nathalie; Lauvau, Grégoire; Grau, Morgan; Wencker, Mélanie; Arpin, Christophe; Walzer, Thierry; Leverrier, Yann; Marvel, Jacqueline

    2016-01-01

    Memory CD8 T lymphocyte populations are remarkably heterogeneous and differ in their ability to protect the host. In order to identify the whole range of qualities uniquely associated with protective memory cells we compared the gene expression signatures of two qualities of memory CD8 T cells sharing the same antigenic-specificity: protective (Influenza-induced, Flu-TM) and non-protective (peptide-induced, TIM) spleen memory CD8 T cells. Although Flu-TM and TIM express classical phenotypic memory markers and are polyfunctional, only Flu-TM protects against a lethal viral challenge. Protective memory CD8 T cells express a unique set of genes involved in migration and survival that correlate with their unique capacity to rapidly migrate within the infected lung parenchyma in response to influenza infection. We also enlighten a new set of poised genes expressed by protective cells that is strongly enriched in cytokines and chemokines such as Ccl1, Ccl9 and Gm-csf. CCL1 and GM-CSF genes are also poised in human memory CD8 T cells. These immune signatures are also induced by two other pathogens (vaccinia virus and Listeria monocytogenes). The immune signatures associated with immune protection were identified on circulating cells, i.e. those that are easily accessible for immuno-monitoring and could help predict vaccines efficacy. PMID:27883012

  4. Immune Signature of Enhanced Functional Avidity CD8+ T Cells in vivo Induced by Vaccinia Vectored Vaccine

    PubMed Central

    Hu, Zhidong; Zhu, Lingyan; Wang, Jing; Wan, Yanmin; Yuan, Songhua; Chen, Jian; Ding, Xiangqing; Qiu, Chenli; Zhang, Xiaoyan; Qiu, Chao; Xu, Jianqing

    2017-01-01

    Functional avidity of T cells is a critical determinant for clearing viral infection and eliminating tumor. Understanding how functional avidity is maintained in T cells is imperative for immunotherapy. However, studies systematically characterize T cell with high functional avidity induced in vivo are still lacking. Previously, we and others found vaccinia vectored vaccine (VACV) induced antigen-specific CD8+ T cells with relatively high functional avidity to those from DNA vaccine. Herein, we used functional, immune phenotyping and transcriptomic studies to define the immune signature of these CD8+ T cells with high functional avidity. Antigen-specific CD8+ T cells induced by VACV executed superior in vivo killing activity and displayed a distinct transcriptional profile, whereas no significantly differences were found in composition of memory sub-populations and cytokine poly-functionality. Transcriptional analyses revealed unique features of VACV induced CD8+ T cells in several biological processes, including transport, cell cycle, cell communication and metabolic processes. In summary, we characterize CD8+ T cells of high functional avidity induced in vivo by VACV, which not only improves our understanding of adaptive T cell immunity in VACV vaccination, but also provides clues to modulate functional avidity of CD8+ T cells for T cell based immunotherapy. PMID:28155878

  5. Investigation of alpha nascent polypeptide-associated complex functions in a human CD8+ T cell ex vivo expansion model using antisense oligonucleotides

    PubMed Central

    Al-Shanti, N; Steward, C G; Garland, R J; Rowbottom, A W

    2004-01-01

    In order to determine molecules involved in the differentiation and proliferation of human CD8+ cells, two ex vivo expansion models were established: coculture of freshly purified human CD8+ cells with irradiated autologous feeders (AF) or stimulation with anti-CD3. Two different proliferation kinetics of CD8+ cells and expression patterns of CD57 were observed between these conditions. Differential display reverse transcriptase–polymerase chain reaction was applied to investigate the differential expression of mRNA species between CD8+ CD57+ and CD8+ CD57– populations. A differentially expressed RNA species called alpha nascent polypeptide associated complex (α NAC) was found at a higher level in CD8+ CD57– cells than in CD8+ CD57+ cells. In the presence of AF, the expression of α NAC was reduced on culturing whilst proliferation increased. Similarly, in cultures stimulated with anti-CD3, α NAC reverted to its inactive form and differentiation and proliferation increased. Using a phosphorothioate-modified oligodeoxynucleotide antisense directed specifically against α NAC mRNA, protein expression was inhibited and increased CD8+ cell proliferation and CD25 expression were observed irrespective of the culture conditions. This suggests that α NAC protein is antiproliferative molecule. This is the first description of the function of the α NAC protein in human CD8+ T cells. PMID:15196207

  6. Initiation of Antiretroviral Therapy (ART) at Different Stages of HIV-1 Disease Is Not Associated with the Proportion of Exhausted CD8+ T Cells.

    PubMed

    Jensen, Sanne Skov; Fomsgaard, Anders; Larsen, Tine Kochendorf; Tingstedt, Jeanette Linnea; Gerstoft, Jan; Kronborg, Gitte; Pedersen, Court; Karlsson, Ingrid

    2015-01-01

    CD8+ T cell-restricted immunity is important in the control of HIV-1 infection, but continued immune activation results in CD8+ T cell dysfunction. Early initiation of antiretroviral treatment (ART) and the duration of ART have been associated with immune reconstitution. Here, we evaluated whether restoration of CD8+ T cell function in HIV-1-infected individuals was dependent on early initiation of ART. HIV-specific CD107a, IFNγ, IL-2, TNFα and MIP-1β expression by CD8+ T cells and the frequency of CD8+ T cells expressing PD-1, 2B4 and CD160 were measured by flow cytometry. The frequency of CD8+ T cells expressing the inhibitory markers PD-1, 2B4 and CD160 was lower in ART-treated individuals compared with ART-naïve individuals and similar to the frequency in HIV-uninfected controls. The expression of the three markers was similarly independent of when therapy was initiated. Individuals treated before seroconversion displayed an HIV-specific CD8+ T cell response that included all five functional markers; this was not observed in individuals treated after seroconversion or in ART-naïve individuals. In summary, ART appears to restore the total CD8+ T cell population to a less exhausted phenotype, independent of the time point of initiation. However, to preserve multifunctional, HIV-1-specific CD8+ T cells, ART might have to be initiated before seroconversion.

  7. TLR4 ligands lipopolysaccharide and monophosphoryl lipid a differentially regulate effector and memory CD8+ T Cell differentiation.

    PubMed

    Cui, Weiguo; Joshi, Nikhil S; Liu, Ying; Meng, Hailong; Kleinstein, Steven H; Kaech, Susan M

    2014-05-01

    Vaccines formulated with nonreplicating pathogens require adjuvants to help bolster immunogenicity. The role of adjuvants in Ab production has been well studied, but how they influence memory CD8(+) T cell differentiation remains poorly defined. In this study we implemented dendritic cell-mediated immunization to study the effects of commonly used adjuvants, TLR ligands, on effector and memory CD8(+) T cell differentiation in mice. Intriguingly, we found that the TLR4 ligand LPS was far more superior to other TLR ligands in generating memory CD8(+) T cells upon immunization. LPS boosted clonal expansion similar to the other adjuvants, but fewer of the activated CD8(+) T cells died during contraction, generating a larger pool of memory cells. Surprisingly, monophosphoryl lipid A (MPLA), another TLR4 ligand, enhanced clonal expansion of effector CD8(+) T cells, but it also promoted their terminal differentiation and contraction; thus, fewer memory CD8(+) T cells formed, and MPLA-primed animals were less protected against secondary infection compared with those primed with LPS. Furthermore, gene expression profiling revealed that LPS-primed effector cells displayed a stronger pro-memory gene expression signature, whereas the gene expression profile of MPLA-primed effector cells aligned closer with terminal effector CD8(+) T cells. Lastly, we demonstrated that the LPS-TLR4-derived "pro-memory" signals were MyD88, but not Toll/IL-1R domain-containing adapter inducing IFN-β, dependent. This study reveals the influential power of adjuvants on the quantity and quality of CD8(+) T cell memory, and that attention to adjuvant selection is crucial because boosting effector cell expansion may not always equate with more memory T cells or greater protection.

  8. Prostate stem cell antigen: Identification of immunogenic peptides and assessment of reactive CD8+ T cells in prostate cancer patients.

    PubMed

    Kiessling, Andrea; Schmitz, Marc; Stevanovic, Stefan; Weigle, Bernd; Hölig, Kristina; Füssel, Monika; Füssel, Susanne; Meye, Axel; Wirth, Manfred P; Rieber, Ernst Peter

    2002-12-01

    Identification of TAAs recognized by CD8(+) CTLs paved the way for new concepts in cancer therapy. In view of the heterogeneity of tumors and their diverse escape mechanisms, CTL-based cancer therapy largely depends on an appropriate number of TAAs. In prostate cancer, the number of antigens defined as suitable targets of CTLs remains rather limited. PSCA is widely distributed in prostate cancer. In this report, we define immunogenic peptides of PSCA which are recognized by circulating CD8(+) T cells from prostate cancer patients and able to activate CTLs in vitro. Screening the amino acid sequence of PSCA for peptides containing a binding motif for HLA-A*0201 resulted in 8 candidate peptides. Specificity and affinity of peptide binding were verified in a competition assay. Frequencies of CD8(+) T lymphocytes reactive against selected epitopes were determined in the blood of prostate cancer patients using the ELISPOT assay. Increased frequencies were revealed for CD8(+) T cells recognizing the peptides ALQPGTALL and AILALLPAL. CTLs from prostate cancer patients were raised against these 2 peptides in vitro when presented by autologous DCs. They specifically recognized peptide-pulsed T2 target cells and prostate cancer cells that were HLA-A*0201- and PSCA-positive, indicating that these peptides were naturally generated by tumor cells. These data suggest that PSCA is a promising target for the immunotherapy of prostate cancer.

  9. The CD8alpha(+) dendritic cell is responsible for inducing peripheral self-tolerance to tissue-associated antigens.

    PubMed

    Belz, Gabrielle T; Behrens, Georg M N; Smith, Chris M; Miller, Jacques F A P; Jones, Claerwen; Lejon, Kristina; Fathman, C Garrison; Mueller, Scott N; Shortman, Ken; Carbone, Francis R; Heath, William R

    2002-10-21

    We previously described a mechanism for the maintenance of peripheral self-tolerance. This involves the cross-presentation of tissue-associated antigens by a bone marrow-derived cell type that stimulates the proliferation and ultimate deletion of self-reactive CD8 T cells. This process has been referred to as cross-tolerance. Here, we characterize the elusive cell type responsible for inducing cross-tolerance as a CD8alpha(+) dendritic cell (DC). To achieve this aim, transgenic mice were generated expressing yellow fluorescent protein (YFP) linked to CTL epitopes for ovalbumin and glycoprotein B (gB) of herpes simplex virus under the rat insulin promoter (RIP). Although tracking of YFP was inconclusive, the use of a highly sensitive gB-specific hybridoma that produced beta-galactosidase on encounter with antigen, enabled detection of antigen presentation by cells isolated from the pancreatic lymph node. This showed that a CD11c(+)CD8alpha(+) cell was responsible for cross-tolerance, the same DC subset as previously implicated in cross-priming. These data indicate that CD8alpha(+) DCs play a critical role in both tolerance and immunity to cell-associated antigens, providing a potential mechanism by which cytotoxic T lymphocyte can be immunized to viral antigens while maintaining tolerance to self.

  10. Immunoproteasomes are essential for clearance of Listeria monocytogenes in nonlymphoid tissues but not for induction of bacteria-specific CD8+ T cells.

    PubMed

    Strehl, Britta; Joeris, Thorsten; Rieger, Melanie; Visekruna, Alexander; Textoris-Taube, Kathrin; Kaufmann, Stefan H E; Kloetzel, Peter-Michael; Kuckelkorn, Ulrike; Steinhoff, Ulrich

    2006-11-01

    Microbial infections induce the replacement of constitutive proteasomes by immunoproteasomes (I-proteasomes). I-proteasomes support efficient generation of MHC class I epitopes and influence immunodominance hierarchies of CD8(+) T cells. Recently, the function of I-proteasomes in antimicrobial responses was challenged by showing that the lack of I-proteasomes has no effect on induction and function of lymphocytic choriomeningitis virus-specific CD8(+) T cells. Here, we show that infection with Listeria monocytogenes rapidly induces I-proteasomes in nonlymphoid tissues, which leads to enhanced generation of protection relevant CD8(+) T cell epitopes. I-proteasome-deficient mice (beta5i(-/-) mice) exhibited normal frequencies of L. monocytogenes-specific CD8(+) T cells. However, clearance of L. monocytogenes in liver but not spleen was significantly impaired in I-proteasome-deficient mice. In summary, our studies demonstrate that induction of I-proteasomes is required for CD8(+) T cell-mediated elimination of L. monocytogenes from nonlymphoid but not lymphoid tissues.

  11. Tracking antigen-specific CD8⁺ T cells using MHC class I multimers.

    PubMed

    Alanio, Cécile; Bouvier, Isabelle; Jusforgues-Saklani, Hélène; Albert, Matthew L

    2013-01-01

    The tracking of epitope-specific T cells is a useful approach for the study of adaptive immune responses. This protocol describes how Major Histocompatibility Complex Class I (MHC-I) multimers can be used to stain, enrich, and enumerate (rare) populations of CD8(+) T cells specific for a given antigen. It provides the detailed steps for multimer labeling, magnetic enrichment, and cytometric analysis. Additionally, it provides informations for multiplexing experiments in order to achieve simultaneous detection of multiple antigenic specificities, and strategies for coupling the protocol with functional assays (e.g., intracellular cytokine staining). Future developments in cytometric systems (e.g., mass spectroscopy-based cytometry) and gene expression studies (e.g., single cell PCR) will extend these approaches and provide an unprecedented assessment of the immune repertoire.

  12. CD8-positive Mycosis Fungoides Masquerading as Pyoderma Gangrenosum

    PubMed Central

    Saha, Maitrayee; Jain, Bhawna Bhutoria; Chattopadhyay, Sarbani; Podder, Indrashis

    2016-01-01

    Mycosis fungoides (MF), a primary cutaneous T-cell lymphoma, accounts for <1% of non-Hodgkin lymphomas. The diagnosis of classic MF is based on a constellation of typical clinical presentation, histopathology, immunohistochemistry, and T-cell monoclonality detected by molecular studies. Rarely, atypical clinical presentation may occur. The typical immunohistochemical phenotype is, CD2 +ve, CD3 +ve, CD5 +ve, CD4 +ve, and CD8 − ve. Here, we report a rare case of CD8 +ve MF in a 43-year-male patient who was clinically diagnosed as pyoderma gangrenosum initially. The atypical presentation and rarity of such case have prompted this report. PMID:27688458

  13. DNA immunization combined with scFv phage display identifies antagonistic GCGR specific antibodies and reveals new epitopes on the small extracellular loops.

    PubMed

    van der Woning, Bas; De Boeck, Gitte; Blanchetot, Christophe; Bobkov, Vladimir; Klarenbeek, Alex; Saunders, Michael; Waelbroeck, Magali; Laeremans, Toon; Steyaert, Jan; Hultberg, Anna; De Haard, Hans

    2016-01-01

    The identification of functional monoclonal antibodies directed against G-protein coupled receptors (GPCRs) is challenging because of the membrane-embedded topology of these molecules. Here, we report the successful combination of llama DNA immunization with scFv-phage display and selections using virus-like particles (VLP) and the recombinant extracellular domain of the GPCR glucagon receptor (GCGR), resulting in glucagon receptor-specific antagonistic antibodies. By immunizing outbred llamas with plasmid DNA containing the human GCGR gene, we sought to provoke their immune system, which generated a high IgG1 response. Phage selections on VLPs allowed the identification of mAbs against the extracellular loop regions (ECL) of GCGR, in addition to multiple VH families interacting with the extracellular domain (ECD) of GCGR. Identifying mAbs binding to the ECL regions of GCGR is challenging because the large ECD covers the small ECLs in the energetically most favorable 'closed conformation' of GCGR. Comparison of Fab with scFv-phage display demonstrated that the multivalent nature of scFv display is essential for the identification of GCGR specific clones by selections on VLPs because of avid interaction. Ten different VH families that bound 5 different epitopes on the ECD of GCGR were derived from only 2 DNA-immunized llamas. Seven VH families demonstrated interference with glucagon-mediated cAMP increase. This combination of technologies proved applicable in identifying multiple functional binders in the class B GPCR context, suggesting it is a robust approach for tackling difficult membrane proteins.

  14. Identification of Effective Subdominant Anti-HIV-1 CD8+ T Cells Within Entire Post-infection and Post-vaccination Immune Responses

    PubMed Central

    Hancock, Gemma; Yang, Hongbing; Yorke, Elisabeth; Wainwright, Emma; Bourne, Victoria; Frisbee, Alyse; Payne, Tamika L.; Berrong, Mark; Ferrari, Guido; Chopera, Denis; Hanke, Tomas; Mothe, Beatriz; Brander, Christian; McElrath, M. Juliana; McMichael, Andrew; Goonetilleke, Nilu; Tomaras, Georgia D.; Frahm, Nicole; Dorrell, Lucy

    2015-01-01

    Defining the components of an HIV immunogen that could induce effective CD8+ T cell responses is critical to vaccine development. We addressed this question by investigating the viral targets of CD8+ T cells that potently inhibit HIV replication in vitro, as this is highly predictive of virus control in vivo. We observed broad and potent ex vivo CD8+ T cell-mediated viral inhibitory activity against a panel of HIV isolates among viremic controllers (VC, viral loads <5000 copies/ml), in contrast to unselected HIV-infected HIV Vaccine trials Network (HVTN) participants. Viral inhibition of clade-matched HIV isolates was strongly correlated with the frequency of CD8+ T cells targeting vulnerable regions within Gag, Pol, Nef and Vif that had been identified in an independent study of nearly 1000 chronically infected individuals. These vulnerable and so-called “beneficial” regions were of low entropy overall, yet several were not predicted by stringent conservation algorithms. Consistent with this, stronger inhibition of clade-matched than mismatched viruses was observed in the majority of subjects, indicating better targeting of clade-specific than conserved epitopes. The magnitude of CD8+ T cell responses to beneficial regions, together with viral entropy and HLA class I genotype, explained up to 59% of the variation in viral inhibitory activity, with magnitude of the T cell response making the strongest unique contribution. However, beneficial regions were infrequently targeted by CD8+ T cells elicited by vaccines encoding full-length HIV proteins, when the latter were administered to healthy volunteers and HIV-positive ART-treated subjects, suggesting that immunodominance hierarchies undermine effective anti-HIV CD8+ T cell responses. Taken together, our data support HIV immunogen design that is based on systematic selection of empirically defined vulnerable regions within the viral proteome, with exclusion of immunodominant decoy epitopes that are irrelevant

  15. PD-1 and Tim-3 regulate the expansion of tumor antigen-specific CD8+ T cells induced by melanoma vaccines

    PubMed Central

    Fourcade, Julien; Sun, Zhaojun; Pagliano, Ornella; Chauvin, Joe-Marc; Sander, Cindy; Janjic, Bratislav; Tarhini, Ahmad A.; Tawbi, Hussein A.; Kirkwood, John M.; Moschos, Stergios; Wang, Hong; Guillaume, Philippe; Luescher, Immanuel F.; Krieg, Arthur; Anderson, Ana C.; Kuchroo, Vijay K.; Zarour, Hassane M.

    2014-01-01

    Although melanoma vaccines stimulate tumor antigen (TA)-specific CD8+ T cells, objective clinical responses are rarely observed. To investigate this discrepancy, we evaluated the character of vaccine-induced CD8+ T cells with regard to the inhibitory T cell co-receptors PD-1 and Tim-3 in metastatic melanoma patients who were administered tumor vaccines. The vaccines included incomplete Freund's adjuvant (IFA), CpG oligodeoxynucleotide (CpG) and the HLA-A2-restricted analog peptide NY-ESO-1 157-165V, either by itself or in combination with the pan-DR epitope NY-ESO-1 119-143. Both vaccines stimulated rapid TA-specific CD8+ T-cell responses detected ex vivo, however, TA-specific CD8+ T cells produced more IFN-γ and exhibited higher lytic function upon immunization with MHC class I and class II epitopes. Notably, the vast majority of vaccine-induced CD8+ T cells upregulated PD-1 and a minority also upregulated Tim-3. Levels of PD-1 and Tim-3 expression by vaccine-induced CD8+ T cells at the time of vaccine administration correlated inversely with their expansion in vivo. Dual blockade of PD-1 and Tim-3 enhanced the expansion and cytokine production of vaccine-induced CD8+ T cells in vitro. Collectively, our findings support the use of PD-1 and Tim-3 blockades with cancer vaccines to stimulate potent antitumor T cell responses and increase the likelihood of clinical responses in advanced melanoma patients. PMID:24343228

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

    PubMed Central

    O’Flaherty, Brigid M.; Matar, Caline G.; Wakeman, Brian S.; Garcia, AnaPatricia; Wilke, Carol A.; Courtney, Cynthia L.; Moore, Bethany B.; Speck, Samuel H.

    2015-01-01

    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. PMID:26317335

  17. Modulation of HCV-specific CD8 effector T-cell function with antiviral effect in infectious hepatitis C virus co-culture model.

    PubMed

    Ojiro, Keisuke; Qu, Xiaowang; Cho, Hyosun; Park, Jang-June; Vuidepot, Annelise; Lissin, Nikolai; Molloy, Peter E; Bennett, Alan; Jakobsen, Bent K; Kaplan, David E; Riley, James L; Chang, Kyong-Mi

    2017-03-08

    Antiviral effects of hepatitis C virus (HCV)-specific CD8 T-cells have been shown in HCV replicon, but not in authentic infectious cell culture system (HCVcc). Here, we developed tools to examine the antigenicity of HCV-infected HLA A2+ Huh7.5 hepatoma cells (Huh7.5A2) in activating HCV-specific CD8 T-cells with downstream antiviral effects. Infectious HCV epitope mutants encoding well-defined genotype 1a-derived HLA A2-restricted HCV NS3 1073 or NS5 2594 epitope were generated from genotype 2a-derived HCV clone (Jc1Gluc2A) by site-directed mutagenesis. CD8 T-cell lines specific for NS3 1073 and NS5 2594 were expanded from HCV-seropositive persons by peptide stimulation in-vitro or engineered from HCV-seronegative donor T-cells by lentiviral transduction of HCV-specific T-cell receptors. HCV-specific CD8 T-cells were co-cultured with Huh7.5 cells that were pulsed with titrating doses of HCV epitope peptides or infected with HCV epitope mutants. HCV-specific CD8 T-cell activation (CD107, IFNγ, MIP-1β, TNFα) was dose-dependent on peptide concentrations and relative percentages of HCV-infected Huh7.5A2 cells. HCV-infected Huh7.5A2 cells activated HCV-specific CD8 T-cells at levels comparable to 0.1-2μM pulsed peptides, providing a novel estimate at which endogenously processed HCV epitopes are presented in HCV-infected cells. While HCV-specific CD8 T-cell activation with cytolytic and antiviral effects was blunted by PD-L1 expression on HCV-infected Huh7.5A2 cells with improved viability of Huh7.5A2 cells, PD-1 blockade reversed this effect with enhanced cytolytic elimination of HCV-infected Huh7.5A2 cells. Our findings using infectious HCVcc system show that HCV-specific CD8 T-cell function is modulated by antigen expression levels, percentage of HCV-infected cells and PD-1/PD-L1 pathways, with antiviral and cytotoxic effects.IMPORTANCE We developed several novel molecular and immunological tools to study interactions between HCV, HCV-infected hepatocytes and HCV

  18. Regulatory T Cell Effect on CD8(+) T Cell Responses to Human Herpesvirus 8 Infection and Development of Kaposi's Sarcoma.

    PubMed

    Lepone, Lauren M; Rappocciolo, Giovanna; Piazza, Paolo A; Campbell, Diana M; Jenkins, Frank J; Rinaldo, Charles R

    2017-03-02

    We assessed CD8(+) T cell reactivity to human herpesvirus 8 (HHV-8; Kaposi's sarcoma [KS]-associated herpesvirus) and the role of CD4(+)CD25(hi)FoxP3(+) regulatory T cells (Treg) in HHV-8- and HIV-coinfected participants of the Multicenter AIDS Cohort Study who did or did not develop KS. There were similarly low CD8(+) T cell interferon-γ responses to MHC class I-restricted epitopes of HHV-8 lytic and latent proteins over 5.7 years before KS in participants who developed KS compared to those who did not. T cell reactivity to HHV-8 antigens was low relative to responses to a combination of cytomegalovirus, Epstein-Barr virus and influenza A virus (CEF) peptide epitopes, and dominant HIV peptide epitopes. There was no change in %Treg in the HHV-8- and HIV-coinfected participants who did not develop KS, whereas there was a significant increase in %Treg in HHV-8- and HIV-coinfected participants who developed KS beginning 1.8 years before development of KS. Removal of Treg enhanced HHV-8-specific T cell responses in HHV-8- and HIV-coinfected participants who did or did not develop KS, with a similar pattern observed in response to CEF and HIV peptides. Thus, long-term, low levels of anti-HHV-8 CD8(+) T cell reactivity were present in both HHV-8- and HIV-coinfected men who did and did not develop KS. This was related to moderately enhanced Treg function.

  19. Protective immune responses against systemic candidiasis mediated by phage-displayed specific epitope of Candida albicans heat shock protein 90 in C57BL/6J mice.

    PubMed

    Wang, Guiyun; Sun, Meiyan; Fang, Jinbo; Yang, Qiong; Tong, Haibin; Wang, Li

    2006-08-28

    Specific epitope (DEPAGE) of Candida albicans heat shock protein 90 (SE-CA-HSP90) was successfully expressed on the surface of filamentous phage fd, fused to the major coat protein pVIII. Protective immune responses mediated by hybrid-phage expressing SE-CA-HSP90 in C57BL/6J mice were evaluated in this paper. The results showed that hybrid-phage particles induced the specific antibody response against SE-CA-HSP90, enhanced delayed-type hypersensitivity (DTH) response, natural killer (NK) cell activity and concanavalin A (ConA)-induced splenocyte proliferation. Furthermore, this study demonstrated that hybrid-phage-immunized mice had fewer colony forming unites (CFU) in the kidneys compared with wild-type phage-immunized mice and TE (1.0mM EDTA, 0.01M Tris-HCl, pH 8.0)-injected mice and showed statistically significant survival advantage over TE-injected group. In conclusion, the results suggest that the hybrid-phage displaying SE-CA-HSP90 may be considered as a potential candidate for producing vaccines against systemic candidiasis.

  20. CD8 Co-receptor promotes susceptibility of CD8+ T cells to transforming growth factor-β (TGF-β)-mediated suppression

    PubMed Central

    Zloza, Andrew; Jagoda, Michael C.; Lyons, Gretchen E.; Graves, Michael C.; Kohlhapp, Frederick J.; O’Sullivan, Jeremy A.; Lacek, Andrew T.; Nishimura, Michael I.

    2015-01-01

    CD8+ T cell function depends on a finely orchestrated balance of activation/suppression signals. While the stimulatory role of the CD8 co-receptor and pleiotropic capabilities of TGF-β have been studied individually, the influence of CD8 co-receptor on TGF-β function in CD8+ T cells is unknown. Here, we show that while CD8 enhances T cell activation, it also enhances susceptibility to TGF-β-mediated immune suppression. Using Jurkat cells expressing a full-length, truncated or no αβCD8 molecule, we demonstrate that cells expressing full-length αβCD8 were highly susceptible, αβCD8-truncated cells were partially susceptible, and CD8-deficient cells were completely resistant to suppression by TGF-β. Additionally, we determined that inhibition of Lck rendered mouse CD8+ T cells highly resistant to TGF-β suppression. Resistance was not associated with TGF-β receptor expression but did correlate with decreased Smad3 and increased Smad7 levels. These findings highlight a previously unrecognized third role for CD8 co-receptor which appears to prepare activated CD8+ T cells for response to TGF-β. Based on the important role which TGF-β-mediated suppression plays in tumor immunology, these findings unveil necessary considerations in formulation of CD8+ T cell-related cancer immunotherapy strategies. PMID:21193909

  1. CD8low CD100− T Cells Identify a Novel CD8 T Cell Subset Associated with Viral Control during Human Hantaan Virus Infection

    PubMed Central

    Liu, Bei; Ma, Ying; Zhang, Yusi; Zhang, Chunmei; Yi, Jing; Zhuang, Ran; Yu, Haitao; Yang, Angang

    2015-01-01

    ABSTRACT Hantaan virus (HTNV) infection can cause a severe lethal hemorrhagic fever with renal syndrome (HFRS) in humans. CD8+ T cells play a critical role in combating HTNV infections. However, the contributions of different CD8+ T cell subsets to the immune response against viral infection are poorly understood. Here, we identified a novel subset of CD8+ T cells characterized by the CD8low CD100− phenotype in HFRS patients. The CD8low CD100− subset accounted for a median of 14.3% of the total CD8+ T cells in early phase of HFRS, and this percentage subsequently declined in the late phase of infection, whereas this subset was absent in healthy controls. Furthermore, the CD8low CD100− cells were associated with high activation and expressed high levels of cytolytic effector molecules and exhibited a distinct expression profile of effector CD8+ T cells (CCR7+/− CD45RA− CD127high CD27int CD28low CD62L−). When stimulated with specific HTNV nucleocapsid protein-derived peptide pools, most responding CD8+ cells (gamma interferon [IFN-γ] positive and/or tumor necrosis factor alpha [TNF-α] positive) were CD8low CD100− cells. The frequency of CD8low CD100− cells among HTNV-specific CD8+ T cells was higher in milder cases than in more severe cases. Importantly, the proportion of the CD8low CD100− subset among CD8+ T cells in early phase of HFRS was negatively correlated with the HTNV viral load, suggesting that CD8low CD100− cells may be associated with viral clearance. The contraction of the CD8low CD100− subset in late phase of infection may be related to the consistently high expression levels of PD-1. These results may provide new insights into our understanding of CD8+ T cell-mediated protective immunity as well as immune homeostasis after HTNV infection in humans. IMPORTANCE CD8+ T cells play important roles in the antiviral immune response. We found that the proportion of CD8low CD100− cells among CD8+ T cells from HFRS patients was

  2. A new EV71 VP3 epitope in norovirus P particle vector displays neutralizing activity and protection in vivo in mice.

    PubMed

    Jiang, Liping; Fan, Rongjun; Sun, Shiyang; Fan, Peihu; Su, Weiheng; Zhou, Yan; Gao, Feng; Xu, Fei; Kong, Wei; Jiang, Chunlai

    2015-11-27

    Enterovirus 71 (EV71) and Coxsackievirus A16 (CVA16), as the main agents causing hand, foot and mouth disease (HFMD), have become a serious public health concern in the Asia-Pacific region. Recently, various neutralizing B cell epitopes of EV71 were identified as targets for promising vaccine candidates. Structural studies of Picornaviridae indicated that potent immunodominant epitopes typically lie in the hypervariable loop of capsid surfaces. However, cross-neutralizing antibodies and cross-protection between EV71 and CVA16 have not been observed. Therefore, we speculated that divergent sequences of the two viruses are key epitopes for inducing protective neutralizing responses. In this study, we selected 10 divergent epitope candidates based on alignment of the EV71 and CVA16 P1 amino acid sequences using the Multalin interface page, and these epitopes are conserved among all subgenotypes of EV71. Simultaneously, by utilizing the norovirus P particle as a novel vaccine delivery carrier, we identified the 71-6 epitope (amino acid 176-190 of VP3) as a conformational neutralizing epitope against EV71 in an in vitro micro-neutralization assay as well as an in vivo protection assay in mice. Altogether, these results indicated that the incorporation of the 71-6 epitope into the norovirus P domain can provide a promising candidate for an effective synthetic peptide-based vaccine against EV71.

  3. Mathematical Model Reveals the Role of Memory CD8 T Cell Populations in Recall Responses to Influenza

    PubMed Central

    Zarnitsyna, Veronika I.; Handel, Andreas; McMaster, Sean R.; Hayward, Sarah L.; Kohlmeier, Jacob E.; Antia, Rustom

    2016-01-01

    The current influenza vaccine provides narrow protection against the strains included in the vaccine, and needs to be reformulated every few years in response to the constantly evolving new strains. Novel approaches are directed toward developing vaccines that provide broader protection by targeting B and T cell epitopes that are conserved between different strains of the virus. In this paper, we focus on developing mathematical models to explore the CD8 T cell responses to influenza, how they can be boosted, and the conditions under which they contribute to protection. Our models suggest that the interplay between spatial heterogeneity (with the virus infecting the respiratory tract and the immune response being generated in the secondary lymphoid organs) and T cell differentiation (with proliferation occurring in the lymphoid organs giving rise to a subpopulation of resident T cells in the respiratory tract) is the key to understand the dynamics of protection afforded by the CD8 T cell response to influenza. Our results suggest that the time lag for the generation of resident T cells in the respiratory tract and their rate of decay following infection are the key factors that limit the efficacy of CD8 T cell responses. The models predict that an increase in the level of central memory T cells leads to a gradual decrease in the viral load, and, in contrast, there is a sharper protection threshold for the relationship between the size of the population of resident T cells and protection. The models also suggest that repeated natural influenza infections cause the number of central memory CD8 T cells and the peak number of resident memory CD8 T cells to reach their plateaus, and while the former is maintained, the latter decays with time since the most recent infection. PMID:27242779

  4. Subtractive phage display selection from canine visceral leishmaniasis identifies novel epitopes that mimic Leishmania infantum antigens with potential serodiagnosis applications.

    PubMed

    Costa, Lourena E; Lima, Mayara I S; Chávez-Fumagalli, Miguel A; Menezes-Souza, Daniel; Martins, Vivian T; Duarte, Mariana C; Lage, Paula S; Lopes, Eliane G P; Lage, Daniela P; Ribeiro, Tatiana G; Andrade, Pedro H R; de Magalhães-Soares, Danielle F; Soto, Manuel; Tavares, Carlos A P; Goulart, Luiz R; Coelho, Eduardo A F

    2014-01-01

    Visceral leishmaniasis (VL) is a zoonotic disease that is endemic to Brazil, where dogs are the main domestic parasite reservoirs, and the percentages of infected dogs living in regions where canine VL (CVL) is endemic have ranged from 10% to 62%. Despite technological advances, some problems have been reported with CVL serodiagnosis. The present study describes a sequential subtractive selection through phage display technology from polyclonal antibodies of negative and positive sera that resulted in the identification of potential bacteriophage-fused peptides that were highly sensitive and specific to antibodies of CVL. A negative selection was performed in which phage clones were adhered to purified IgGs from healthy and Trypanosoma cruzi-infected dogs to eliminate cross-reactive phages. The remaining supernatant nonadhered phages were submitted to positive selection against IgG from the blood serum of dogs that were infected with Leishmania infantum. Phage clones that adhered to purified IgGs from the CVL-infected serum samples were selected. Eighteen clones were identified and their reactivities tested by a phage enzyme-linked immunosorbent assay (phage-ELISA) against the serum samples from infected dogs (n = 31) compared to those from vaccinated dogs (n = 21), experimentally infected dogs with cross-reactive parasites (n = 23), and healthy controls (n = 17). Eight clones presented sensitivity, specificity, and positive and negative predictive values of 100%, and they showed no cross-reactivity with T. cruzi- or Ehrlichia canis-infected dogs or with dogs vaccinated with two different commercial CVL vaccines in Brazil. Our study identified eight mimotopes of L. infantum antigens with 100% accuracy for CVL serodiagnosis. The use of these mimotopes by phage-ELISA proved to be an excellent assay that was reproducible, simple, fast, and inexpensive, and it can be applied in CVL-monitoring programs.

  5. MicroRNA Expression Patterns of CD8+ T Cells in Acute and Chronic Brucellosis

    PubMed Central

    Budak, Ferah; Bal, S. Haldun; Tezcan, Gulcin; Guvenc, Furkan; Akalin, E. Halis; Goral, Guher; Deniz, Gunnur

    2016-01-01

    Although our knowledge about Brucella virulence factors and the host response increase rapidly, the mechanisms of immune evasion by the pathogen and causes of chronic disease are still unknown. Here, we aimed to investigate the immunological factors which belong to CD8+ T cells and their roles in the transition of brucellosis from acute to chronic infection. Using miRNA microarray, more than 2000 miRNAs were screened in CD8+ T cells of patients with acute or chronic brucellosis and healthy controls that were sorted from peripheral blood with flow cytometry and validated through qRT-PCR. Findings were evaluated using GeneSpring GX (Agilent) 13.0 software and KEGG pathway analysis. Expression of two miRNAs were determined to display a significant fold change in chronic group when compared with acute or control groups. Both miRNAs (miR-126-5p and miR-4753-3p) were decreased (p <0.05 or fold change > 2). These miRNAs have the potential to be the regulators of CD8+ T cell-related marker genes for chronic brucellosis infections. The differentially expressed miRNAs and their predicted target genes are involved in MAPK signaling pathway, cytokine-cytokine receptor interactions, endocytosis, regulation of actin cytoskeleton, and focal adhesion indicating their potential roles in chronic brucellosis and its progression. It is the first study of miRNA expression analysis of human CD8+ T cells to clarify the mechanism of inveteracy in brucellosis. PMID:27824867

  6. Analysis of a successful HCV-specific CD8+ T cell response in patients with recurrent HCV-infection after orthotopic liver transplantation.

    PubMed

    Gruener, Norbert Hubert; Jung, Maria-Christina; Ulsenheimer, Axel; Gerlach, Joern Tilman; Zachoval, Reinhart; Diepolder, Helmut Michael; Baretton, Gustavo; Schauer, Rolf; Pape, Gerd Rudolf; Schirren, Carl Albrecht

    2004-12-01

    Virus-specific CD8+ T cells play a major role in antiviral immune defenses; their significance in the transplant setting, however, is unclear. In the present study, we asked whether hepatitis C virus (HCV)-specific CD8+ T cells were detectable in the presence of an immunosuppressive treatment and whether the HCV-specific CD8+ T cell response correlates with treatment outcome in patients who receive interferon (IFN)-alpha / ribavirin therapy after orthotopic liver transplantation (OLTx). Liver- and blood-derived T cell lines of 21 patients after OLTx were studied before, at the end of, and after antiviral treatment. Virus-specific IFN-gamma production in response to a panel of previously identified HCV-specific epitopes restricted by the human leukocyte antigen (HLA) class I molecules A2, A3, B7, B35, and B44 of structural and nonstructural HCV protein was determined by enzyme-linked immunospot (ELISPOT) assay. Before treatment, only low numbers of HCV-specific CD8+ T cells were detectable. In 6 patients with a sustained virological response, a significant, multispecific, and sustained CD8+ T cell response was detectable, which was mainly found in the peripheral blood. Nonresponders and transient responders showed undetectable, weak, or transient HCV-specific CD8+ T cell responses. (Sustained responders vs. transient and nonresponders: Wilcoxon rank-signed test; P < .01). In conclusion, our data indicate that despite immunosuppression, HCV-specific CD8+ T cells are detectable in patients with recurrent HCV infection after OLTx and that a significant, multispecific, and long-lasting HCV-specific CD8+ T cell response contributes to viral elimination.

  7. Modulation of CD4+ T Cell-Dependent Specific Cytotoxic CD8+ T Cells Differentiation and Proliferation by the Timing of Increase in the Pathogen Load

    PubMed Central

    Tzelepis, Fanny; Persechini, Pedro M.; Rodrigues, Mauricio M.

    2007-01-01

    Background Following infection with viruses, bacteria or protozoan parasites, naïve antigen-specific CD8+ T cells undergo a process of differentiation and proliferation to generate effector cells. Recent evidences suggest that the timing of generation of specific effector CD8+ T cells varies widely according to different pathogens. We hypothesized that the timing of increase in the pathogen load could be a critical parameter governing this process. Methodology/Principal Findings Using increasing doses of the protozoan parasite Trypanosoma cruzi to infect C57BL/6 mice, we observed a significant acceleration in the timing of parasitemia without an increase in mouse susceptibility. In contrast, in CD8 deficient mice, we observed an inverse relationship between the parasite inoculum and the timing of death. These results suggest that in normal mice CD8+ T cells became protective earlier, following the accelerated development of parasitemia. The evaluation of specific cytotoxic responses in vivo to three distinct epitopes revealed that increasing the parasite inoculum hastened the expansion of specific CD8+ cytotoxic T cells following infection. The differentiation and expansion of T. cruzi-specific CD8+ cytotoxic T cells is in fact dependent on parasite multiplication, as radiation-attenuated parasites were unable to activate these cells. We also observed that, in contrast to most pathogens, the activation process of T. cruzi-specific CD8+ cytotoxic T cells was dependent on MHC class II restricted CD4+ T cells. Conclusions/Significance Our results are compatible with our initial hypothesis that the timing of increase in the pathogen load can be a critical parameter governing the kinetics of CD4+ T cell-dependent expansion of pathogen-specific CD8+ cytotoxic T cells. PMID:17460760

  8. The NK Cell Response to Mouse Cytomegalovirus Infection Affects the Level and Kinetics of the Early CD8+ T-Cell Response

    PubMed Central

    Mitrović, Maja; Arapović, Jurica; Jordan, Stefan; Fodil-Cornu, Nassima; Ebert, Stefan; Vidal, Silvia M.; Krmpotić, Astrid; Reddehase, Matthias J.

    2012-01-01

    Natural killer (NK) cells and CD8+ T cells play a prominent role in the clearance of mouse cytomegalovirus (MCMV) infection. The role of NK cells in modulating the CD8+ T-cell response to MCMV infection is still the subject of intensive research. For analyzing the impact of NK cells on mounting of a CD8+ T-cell response and the contribution of these cells to virus control during the first days postinfection (p.i.), we used C57BL/6 mice in which NK cells are specifically activated through the Ly49H receptor engaged by the MCMV-encoded ligand m157. Our results indicate that the requirement for CD8+ T cells in early MCMV control inversely correlates with the engagement of Ly49H. While depletion of CD8+ T cells has only a minor effect on the early control of wild-type MCMV, CD8+ T cells are essential in the control of Δm157 virus. The frequencies of virus epitope-specific CD8+ T cells and their activation status were higher in mice infected with Δm157 virus. In addition, these mice showed elevated levels of alpha interferon (IFN-α) and several other proinflammatory cytokines as early as 1.5 days p.i. Although the numbers of conventional dendritic cells (cDCs) were reduced later during infection, particularly in Δm157-infected mice, they were not significantly affected at the peak of the cytokine response. Altogether, we concluded that increased antigen load, preservation of early cDCs' function, and higher levels of innate cytokines collectively account for an enhanced CD8+ T-cell response in C57BL/6 mice infected with a virus unable to activate NK cells via the Ly49H–m157 interaction. PMID:22156533

  9. Stalk region of beta-chain enhances the coreceptor function of CD8.

    PubMed

    Wong, Jenny S; Wang, Xiaosong; Witte, Torsten; Nie, Linghu; Carvou, Nicolas; Kern, Petra; Chang, Hsiu-Ching

    2003-07-15

    CD8 glycoproteins are expressed as either alphaalpha homodimers or alphabeta heterodimers on the surface of T cells. CD8alphabeta is a more efficient coreceptor than the CD8alphaalpha for peptide Ag recognition by TCR. Each CD8 subunit is composed of four structural domains, namely, Ig-like domain, stalk region, transmembrane region, and cytoplasmic domain. In an attempt to understand why CD8alphabeta is a better coreceptor than CD8alphaalpha, we engineered, expressed, and functionally tested a chimeric CD8alpha protein whose stalk region is replaced with that of CD8beta. We found that the beta stalk region enhances the coreceptor function of chimeric CD8alphaalpha to a level similar to that of CD8alphabeta. Surprisingly, the beta stalk region also restored functional activity to an inactive CD8alpha variant, carrying an Ala mutation at Arg(8) (R8A), to a level similar to that of wild-type CD8alphabeta. Using the R8A variant of CD8alpha, a panel of anti-CD8alpha Abs, and three MHC class I (MHCI) variants differing in key residues known to be involved in CD8alpha interaction, we show that the introduction of the CD8beta stalk leads to a different topology of the CD8alpha-MHCI complex without altering the overall structure of the Ig-like domain of CD8alpha or causing the MHCI to employ different residues to interact with the CD8alpha Ig domain. Our results show that the stalk region of CD8beta is capable of fine-tuning the coreceptor function of CD8 proteins as a coreceptor, possibly due to its distinct protein structure, smaller physical size and the unique glycan adducts associated with this region.

  10. Comparative evaluation of the CD4+CD8+ and CD4+CD8- lymphocytes in the immune response to porcine rubulavirus.

    PubMed

    Hernández, J; Garfias, Y; Nieto, A; Mercado, C; Montaño, L F; Zenteno, E

    2001-05-30

    The porcine immune system is unique in the expression of CD4+CD8+ (double-positive, DP) lymphocytes. These cells have been associated with immunological memory due to their gradual increase with age, the expression of memory phenotype and their ability to respond to recall viral antigen. This work analyzes the biological function of CD4+CD8- and CD4+CD8+ lymphocytes in the immune response to porcine rubulavirus (PRv). CD4+CD8- cells isolated from pigs 3 weeks after infection with porcine rubulavirus proliferated in response to homologous virus and generated lymphoblasts which were predominantly of the CD4+CD8+ phenotype, whereas stimulation with mitogen induced proliferation but did not switch the phenotype. CD4+CD8- lymphocytes isolated after 10 weeks of infection proliferated in response to phytohemagglutinin (PHA) but did not proliferate in response to homologous virus and did not change their phenotype, whereas CD4+CD8+ lymphocytes proliferated in response to PHA and to viral antigen. The cytokine profile of both lymphocyte populations showed the presence of IL-2 and IL-10 transcripts, quantitation demonstrated that CD4+CD8+ cells expressed mainly IL-10, whereas CD4+CD8- lymphocytes expressed primarily IL-2. Our results show that CD4+CD8- lymphocytes in the early phase of porcine rubulavirus infection can be converted to double-positive cells expressing IL-10 in an antigen-dependent manner, and that CD4+CD8- T-cells late in infection do not acquire CD8.

  11. CD8+ T cell immunity against human respiratory syncytial virus.

    PubMed

    Rossey, Iebe; Sedeyn, Koen; De Baets, Sarah; Schepens, Bert; Saelens, Xavier

    2014-10-21

    Human respiratory syncytial virus (HRSV) was first discovered in the 1950s, but despite decades of research, a licensed vaccine against it is not available. Epidemiological studies indicate that antibodies directed against the fusion protein (F) partially correlate with protection. In addition, an F-specific monoclonal antibody is licensed as a prophylactic treatment in children who are at high risk of developing complications following HRSV infection. Therefore, most HRSV-oriented vaccination strategies focus on inducing a humoral immune response against F. In the quest for the development of a safe HRSV vaccine, the induction of a T cell immune response has received a lot less attention. T cell immunity directed against HRSV has not been associated unequivocally with protection against HRSV and CD4(+) T helper cell responses may even worsen disease due to HRSV. However, many studies support a protective role for CD8(+) T cells in clearance of HRSV from the lungs. In this review we highlight the clinical and experimental evidence in favor of a CD8(+) T lymphocyte-based vaccination strategy to protect against HRSV. First, we describe how T cell responses and T cell memory are induced in the lungs upon respiratory viral infection. HRSV has evolved mechanisms that hamper CD8(+) T cell priming and effector functions. We appraise the information on HRSV-specific CD8(+) T cell immunity gained from laboratory mouse studies, taking into account the advantages and limitations of this animal model and, where possible, the accordance with clinical evidence. Finally, we focus on recent efforts to develop T cell based vaccines against HRSV.

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

    PubMed

    Xu, Weidong; Watts, Douglas M; Costanzo, Margaret C; Tang, Xiaolei; Venegas, Leon A; Jiao, Feng; Sette, Alessandro; Sidney, John; Sewell, Andrew K; Wooldridge, Linda; Makino, Shinji; Morrill, John C; Peters, Clarence J; Kan-Mitchell, June

    2013-01-01

    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.

  13. The Nucleocapsid Protein of Rift Valley Fever Virus Is a Potent Human CD8+ T Cell Antigen and Elicits Memory Responses

    PubMed Central

    Xu, Weidong; Watts, Douglas M.; Costanzo, Margaret C.; Tang, Xiaolei; Venegas, Leon A.; Jiao, Feng; Sette, Alessandro; Sidney, John; Sewell, Andrew K.; Wooldridge, Linda; Makino, Shinji; Morrill, John C.; Peters, Clarence J.; Kan-Mitchell, June

    2013-01-01

    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, N121–129) 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. PMID:23527138

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

    PubMed

    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.

  15. Synthesis and characterisation of self-assembled and self-adjuvanting asymmetric multi-epitope lipopeptides of ovalbumin.

    PubMed

    Eskandari, Sharareh; Stephenson, Rachel J; Fuaad, Abdullah Ahmad; Apte, Simon H; Doolan, Denise L; Toth, Istvan

    2015-01-12

    Designing a lipopeptide (LP) vaccine with a specific asymmetric arrangement of epitopes may result in an improved display of antigens, increasing host-cell recognition and immunogenicity. This study aimed to synthesise and characterise the physicochemical properties of a library of asymmetric LP-based vaccine candidates that contained multiple CD4(+) and CD8(+) T-cell epitopes from the model protein antigen, ovalbumin. These fully synthetic vaccine candidates were prepared by microwave-assisted solid phase peptide synthesis. The C12 or C16 lipoamino acids were coupled to the N or C terminus of the OVA CD4 peptide epitope. The OVA CD4 LPs and OVA CD8 peptide constructs were then conjugated using azide-alkyne Huisgen cycloaddition to give multivalent synthetic vaccines. Physiochemical characterisation of these vaccines showed a tendency to self-assemble in aqueous media. Changes in lipid length and position induced self-assembly with significant changes to their morphology and secondary structure as shown by transmission electron microscopy and circular dichroism.

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

    SciTech Connect

    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

    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.

  17. Self-tolerance eliminates CD4+ T, but not CD8+ T or B, cells corrupting cancer immunotherapy

    PubMed Central

    Snook, Adam E.; Magee, Michael S.; Schulz, Stephanie; Waldman, Scott A.

    2014-01-01

    Self-tolerance, presumably through elimination of all lineages of self antigen-specific lymphocytes (CD4+ T, CD8+ T and B cells), creates a formidable barrier to cancer immunotherapy. In contrast to this prevailing paradigm, we demonstrate that for some antigens self-tolerance reflects selective elimination of antigen-specific CD4+ T, but preservation of CD8+ T and B, cell populations. Antigen-specific CD4+ T cell tolerance is the primary mechanism restricting immunotherapeutic responses to the endogenous self antigen guanylyl cyclase c (GUCY2C) in colorectal cancer. Although CD4+ T cell tolerance blocks antitumor immunity, it offers a unique solution to the inefficacy of cancer vaccines through recruitment of self antigen-independent CD4+ T cell help. Incorporating foreign antigen-specific MHC class II epitopes into self antigen-targeted vaccines against GUCY2C, as well as vaccines targeting endogenous self antigens in melanoma and breast cancer, reconstituted CD4+ T cell help, revealing the latent functional capacity of self antigen-specific CD8+ T and B cell pools, producing durable antitumor immunity without autoimmunity. Identification of self antigens characterized by selective CD4+ T cell tolerance and abrogation of such tolerance through self antigen-independent T cell help is essential for future immunotherapeutic strategies. PMID:24771148

  18. Cooperativity Between CD8+ T Cells, Non-Neutralizing Antibodies, and Alveolar Macrophages Is Important for Heterosubtypic Influenza Virus Immunity

    PubMed Central

    Laidlaw, Brian J.; Decman, Vilma; Ali, Mohammed-Alkhatim A.; Abt, Michael C.; Wolf, Amaya I.; Monticelli, Laurel A.; Mozdzanowska, Krystyna; Angelosanto, Jill M.; Artis, David; Erikson, Jan; Wherry, E. John

    2013-01-01

    Seasonal epidemics of influenza virus result in ∼36,000 deaths annually in the United States. Current vaccines against influenza virus elicit an antibody response specific for the envelope glycoproteins. However, high mutation rates result in the emergence of new viral serotypes, which elude neutralization by preexisting antibodies. T lymphocytes have been reported to be capable of mediating heterosubtypic protection through recognition of internal, more conserved, influenza virus proteins. Here, we demonstrate using a recombinant influenza virus expressing the LCMV GP33-41 epitope that influenza virus-specific CD8+ T cells and virus-specific non-neutralizing antibodies each are relatively ineffective at conferring heterosubtypic protective immunity alone. However, when combined virus-specific CD8 T cells and non-neutralizing antibodies cooperatively elicit robust protective immunity. This synergistic improvement in protective immunity is dependent, at least in part, on alveolar macrophages and/or other lung phagocytes. Overall, our studies suggest that an influenza vaccine capable of eliciting both CD8+ T cells and antibodies specific for highly conserved influenza proteins may be able to provide heterosubtypic protection in humans, and act as the basis for a potential “universal” vaccine. PMID:23516357

  19. Memory CD8+ T cells from naturally-acquired primary dengue virus infection are highly cross-reactive

    PubMed Central

    Friberg, Heather; Burns, Lynne; Woda, Marcia; Kalayanarooj, Siripen; Endy, Timothy P.; Stephens, Henry A.F.; Green, Sharone; Rothman, Alan L.; Mathew, Anuja

    2010-01-01

    Cross-reactive memory T cells induced by primary infection with one of the four serotypes of dengue virus (DENV) are hypothesized to play an immunopathological role in secondary heterologous DENV infection. To define the T cell response to heterologous serotypes, we isolated HLA-A*1101-restricted epitope-specific CD8+ T cell lines from primary DENV-immune donors. Cell lines exhibited marked cross-reactivity towards peptide variants representing the four DENV serotypes in tetramer binding and functional assays. Many clones responded similarly to homologous and heterologous serotypes with striking cross-reactivity between the DENV-1 and DENV-3 epitope variants. In vitro-stimulated T cell lines consistently revealed a hierarchical induction of MIP-1β > degranulation > TNFα > IFNγ, which depended on the concentration of agonistic peptide. Phosphoflow assays demonstrated peptide dose-dependent phosphorylation of ERK1/2, which correlated with cytolysis, degranulation, and induction of TNFα and IFNγ but not MIP-1β production. This is the first study to demonstrate significant DENV serotype-cross-reactivity of CD8+ T cells after naturally-acquired primary infection. We also demonstrate qualitatively different T cell receptor signaling after stimulation with homologous and heterologous peptides. Our data support a model whereby the order of sequential DENV infections influences the immune response to secondary heterologous DENV infection, contributing to varying disease outcomes. PMID:20421879

  20. Memory CD8+ T cells from naturally acquired primary dengue virus infection are highly cross-reactive.

    PubMed

    Friberg, Heather; Burns, Lynne; Woda, Marcia; Kalayanarooj, Siripen; Endy, Timothy P; Stephens, Henry A F; Green, Sharone; Rothman, Alan L; Mathew, Anuja

    2011-01-01

    Cross-reactive memory T cells induced by primary infection with one of the four serotypes of dengue virus (DENV) are hypothesized to have an immunopathological function in secondary heterologous DENV infection. To define the T-cell response to heterologous serotypes, we isolated HLA-A(*)1101-restricted epitope-specific CD8(+) T-cell lines from primary DENV-immune donors. Cell lines exhibited marked cross-reactivity toward peptide variants representing the four DENV serotypes in tetramer binding and functional assays. Many clones responded similarly to homologous and heterologous serotypes with striking cross-reactivity between the DENV-1 and DENV-3 epitope variants. In vitro-stimulated T-cell lines consistently revealed a hierarchical induction of MIP-1β>degranulation>tumor necrosis factor α (TNFα)>interferon-γ (IFNγ), which depended on the concentration of agonistic peptide. Phosphoflow assays showed peptide dose-dependent phosphorylation of ERK1/2, which correlated with cytolysis, degranulation, and induction of TNFα and IFNγ, but not MIP-1β production. This is the first study to show significant DENV serotype-cross-reactivity of CD8(+) T cells after naturally acquired primary infection. We also show qualitatively different T-cell receptor signaling after stimulation with homologous and heterologous peptides. Our data support a model whereby the order of sequential DENV infections influences the immune response to secondary heterologous DENV infection, contributing to varying disease outcomes.

  1. Live attenuated Salmonella displaying HIV-1 10E8 epitope on fimbriae: systemic and mucosal immune responses in BALB/c mice by mucosal administration

    PubMed Central

    Li, Qing-Hai; Jin, Gang; Wang, Jia-Ye; Li, Hai-Ning; Liu, Huidi; Chang, Xiao-Yun; Wang, Fu-Xiang; Liu, Shu-Lin

    2016-01-01

    The HIV-1 membrane proximal external region (MPER) that is targeted by several broadly neutralizing antibodies (BNAbs) has been considered a potential immunogen for vaccine development. However, to date the immunogenicity of these BNAb epitopes has not been made sufficiently adequate. In the present work, we used live attenuated Salmonella as a platform to present the HIV-1 MPER 10E8 epitope in the fimbriae. The insertion of the 10E8 epitope into the fimbriae had no significant influence on the expression and the absorption capacity of bacterial fimbriae, nor on the virulence and invasiveness of the attenuated Salmonella. After oral administration of the vaccine construct to mice followed by 10E8 epitope peptide boost, specific antibody responses in serum and mucosa as well as memory lymphocytes in spleen and plasma cells in bone marrow were induced. We also found that the live attenuated Salmonella vector directed the immunity toward Th1 bias, induced Th1 and Th2 cytokine responses and stimulated significant B cell differentiation into GC B, memory B and plasma cells. Therefore, we propose that the live attenuated Salmonella constitutively expressing HIV-1 BNAb epitopes on the fimbriae will be an effective approach to improving immune microenvironment and enhancing the immunogenicity of HIV-1 epitope vaccines. PMID:27411313

  2. An intact signal peptide on dengue virus E protein enhances immunogenicity for CD8(+) T cells and antibody when expressed from modified vaccinia Ankara.

    PubMed

    Quinan, Bárbara R; Flesch, Inge E A; Pinho, Tânia M G; Coelho, Fabiana M; Tscharke, David C; da Fonseca, Flávio G

    2014-05-23

    Dengue is a global public health concern and this is aggravated by a lack of vaccines or antiviral therapies. Despite the well-known role of CD8(+) T cells in the immunopathogenesis of Dengue virus (DENV), only recent studies have highlighted the importance of this arm of the immune response in protection against the disease. Thus, the majority of DENV vaccine candidates are designed to achieve protective titers of neutralizing antibodies, with less regard for cellular responses. Here, we used a mouse model to investigate CD8(+) T cell and humoral responses to a set of potential DENV vaccines based on recombinant modified vaccinia virus Ankara (rMVA). To enable this study, we identified two CD8(+) T cell epitopes in the DENV-3 E protein in C57BL/6 mice. Using these we found that all the rMVA vaccines elicited DENV-specific CD8(+) T cells that were cytotoxic in vivo and polyfunctional in vitro. Moreover, vaccines expressing the E protein with an intact signal peptide sequence elicited more DENV-specific CD8(+) T cells than those expressing E proteins in the cytoplasm. Significantly, it was these same ER-targeted E protein vaccines that elicited antibody responses. Our results support the further development of rMVA vaccines expressing DENV E proteins and add to the tools available for dengue vaccine development.

  3. Induction of rapid apoptosis for class I MHC molecule-restricted CD8(+) HIV-1 gp160-specific murine activated CTLs by free antigenic peptide in vivo.

    PubMed

    Nakagawa, Yohko; Shimizu, Masumi; Norose, Yoshihiko; Takahashi, Megumi; Takahashi, Hidemi

    2013-01-01

    We have previously reported that the cytotoxic activity of murine CD8(+) CTLs specific for HIV-1 gp160 envelope protein was markedly inhibited in vitro by brief exposure to a free epitope peptide P18-I10 (aa: RGPGRAFVTI) using the epitope-specific CTL line (LINE-IIIB) or a clone (RT-1). We have also shown that recently stimulated P18-I10-specific murine CTLs rapidly fell into apoptosis in vitro after brief exposure to the free epitope peptide. In the present study, we examined whether similar inactivation or apoptosis of recently stimulated CTLs occurred in vivo by exposure to the free epitope peptide using TCR transgenic (Tg-RT-1) mice expressing TCRαβ genes of CTL clone RT-1. When the Tg mice were inoculated with recombinant vaccinia virus expressing HIV-1-IIIB gp160 genes followed by injection of P18-I10 epitope peptide, apparent reduction in the number of CTLs determined by flow cytometry using H-2D(d)/P18-I10 pentamer was observed within a few hours after the injection. Most of the H-2D(d)/P18-I10 pentamer-stained cells were positive for Annexin V and apoptosis was confirmed by microscopic analyses. Moreover, when mice were pretreated with immunosuppressive agents, such as cyclosporin A and tacrolimus (FK506), induction of apoptosis by P18-I10 was significantly inhibited and CTL cytotoxicity was maintained. These results suggest that the rapid loss of virus-specific CD8(+) CTLs might occur in vivo through apoptosis in the early stages of viral infection when activated CTLs may encounter viral epitope(s) released from virus-infected cells attacked by CTLs and we can prevent the loss by pretreatment with immunosuppressive agents.

  4. T Cell Receptor Vβ Staining Identifies the Malignant Clone in Adult T cell Leukemia and Reveals Killing of Leukemia Cells by Autologous CD8+ T cells

    PubMed Central

    Witkover, Aviva; Tanaka, Yuetsu; Fields, Paul; Bangham, Charles R. M.

    2016-01-01

    There is growing evidence that CD8+ cytotoxic T lymphocyte (CTL) responses can contribute to long-term remission of many malignancies. The etiological agent of adult T-cell leukemia/lymphoma (ATL), human T lymphotropic virus type-1 (HTLV-1), contains highly immunogenic CTL epitopes, but ATL patients typically have low frequencies of cytokine-producing HTLV-1-specific CD8+ cells in the circulation. It remains unclear whether patients with ATL possess CTLs that can kill the malignant HTLV-1 infected clone. Here we used flow cytometric staining of TCRVβ and cell adhesion molecule-1 (CADM1) to identify monoclonal populations of HTLV-1-infected T cells in the peripheral blood of patients with ATL. Thus, we quantified the rate of CD8+-mediated killing of the putative malignant clone in ex vivo blood samples. We observed that CD8+ cells from ATL patients were unable to lyse autologous ATL clones when tested directly ex vivo. However, short in vitro culture restored the ability of CD8+ cells to kill ex vivo ATL clones in some donors. The capacity of CD8+ cells to lyse HTLV-1 infected cells which expressed the viral sense strand gene products was significantly enhanced after in vitro culture, and donors with an ATL clone that expressed the HTLV-1 Tax gene were most likely to make a detectable lytic CD8+ response to the ATL cells. We conclude that some patients with ATL possess functional tumour-specific CTLs which could be exploited to contribute to control of the disease. PMID:27893842

  5. T Cell Receptor Vβ Staining Identifies the Malignant Clone in Adult T cell Leukemia and Reveals Killing of Leukemia Cells by Autologous CD8+ T cells.

    PubMed

    Rowan, Aileen G; Witkover, Aviva; Melamed, Anat; Tanaka, Yuetsu; Cook, Lucy B M; Fields, Paul; Taylor, Graham P; Bangham, Charles R M

    2016-11-01

    There is growing evidence that CD8+ cytotoxic T lymphocyte (CTL) responses can contribute to long-term remission of many malignancies. The etiological agent of adult T-cell leukemia/lymphoma (ATL), human T lymphotropic virus type-1 (HTLV-1), contains highly immunogenic CTL epitopes, but ATL patients typically have low frequencies of cytokine-producing HTLV-1-specific CD8+ cells in the circulation. It remains unclear whether patients with ATL possess CTLs that can kill the malignant HTLV-1 infected clone. Here we used flow cytometric staining of TCRVβ and cell adhesion molecule-1 (CADM1) to identify monoclonal populations of HTLV-1-infected T cells in the peripheral blood of patients with ATL. Thus, we quantified the rate of CD8+-mediated killing of the putative malignant clone in ex vivo blood samples. We observed that CD8+ cells from ATL patients were unable to lyse autologous ATL clones when tested directly ex vivo. However, short in vitro culture restored the ability of CD8+ cells to kill ex vivo ATL clones in some donors. The capacity of CD8+ cells to lyse HTLV-1 infected cells which expressed the viral sense strand gene products was significantly enhanced after in vitro culture, and donors with an ATL clone that expressed the HTLV-1 Tax gene were most likely to make a detectable lytic CD8+ response to the ATL cells. We conclude that some patients with ATL possess functional tumour-specific CTLs which could be exploited to contribute to control of the disease.

  6. Estimating In Vivo Death Rates of Targets due to CD8 T-Cell-Mediated Killing▿ †

    PubMed Central

    Ganusov, Vitaly V.; De Boer, Rob J.

    2008-01-01

    Despite recent advances in immunology, several key parameters determining virus dynamics in infected hosts remain largely unknown. For example, the rate at which specific effector and memory CD8 T cells clear virus-infected cells in vivo is hardly known for any viral infection. We propose a framework to quantify T-cell-mediated killing of infected or peptide-pulsed target cells using the widely used in vivo cytotoxicity assay. We have reanalyzed recently published data on killing of peptide-pulsed splenocytes by cytotoxic T lymphocytes and memory CD8 T cells specific to NP396 and GP276 epitopes of lymphocytic choriomeningitis virus (LCMV) in the mouse spleen. Because there are so many effector CD8 T cells in spleens of mice at the peak of the immune response, NP396- and GP276-pulsed targets are estimated to have very short half-lives of 2 and 14 min, respectively. After the effector numbers have diminished, i.e., in LCMV-immune mice, the half-lives become 48 min and 2.8 h for NP396- and GP276-expressing targets, respectively. Analysis of several alternative models demonstrates that the estimates of half-life times of peptide-pulsed targets are not affected when changes are made in the model assumptions. Our report provides a unifying framework to compare killing efficacies of CD8 T-cell responses specific to different viral and bacterial infections in vivo, which may be used to compare efficacies of various cytotoxic-T-lymphocyte-based vaccines. PMID:18815293

  7. An immunodominant HLA-A*1101-restricted CD8+ T-cell response targeting hepatitis B surface antigen in chronic hepatitis B patients.

    PubMed

    Chen, Xiaoling; Wang, Wenbo; Wang, Shufeng; Meng, Gang; Zhang, Mengjun; Ni, Bing; Wu, Yuzhang; Wang, Li

    2013-12-01

    Hepatitis B virus (HBV) infection is a worldwide public health problem. HBV-specific CD8(+) CTLs are vital for viral clearance. Identification of immunodominant CTL epitopes from HBV-associated antigens is necessary for therapeutic vaccine development. We showed that the HLA-A*1101 allele is one of the most common alleles in both healthy individuals and chronic hepatitis B (CHB) patients in the Chongqing area, China. However, less than 10% of epitopes of HBV-associated antigens have been identified in an HLA-A*1101 context. Here, we describe an immunodominant CD8(+) T-cell response targeting a hepatitis B surface antigen determinant (HBs(295-304)) restricted by HLA-A*1101 in both healthy individuals and CHB patients. Moreover, HBs(295-304) is more immunogenic for CTL induction than a known naturally HLA-A*1101-processed epitope from hepatitis B core antigen (HBc(88-96)). Therefore, the newly identified epitope, HBs(295-304), will benefit the development of immunotherapeutic approaches for HBV infection.

  8. Cytomegalovirus Reinfections Stimulate CD8 T-Memory Inflation

    PubMed Central

    Trgovcich, Joanne; Kincaid, Michelle; Thomas, Alicia; Griessl, Marion; Zimmerman, Peter; Dwivedi, Varun; Bergdall, Valerie; Klenerman, Paul

    2016-01-01

    Cytomegalovirus (CMV) has been shown to induce large populations of CD8 T-effector memory cells that unlike central memory persist in large quantities following infection, a phenomenon commonly termed “memory inflation”. Although murine models to date have shown very large and persistent CMV-specific T-cell expansions following infection, there is considerable variability in CMV-specific T-memory responses in humans. Historically such memory inflation in humans has been assumed a consequence of reactivation events during the life of the host. Because basic information about CMV infection/re-infection and reactivation in immune competent humans is not available, we used a murine model to test how primary infection, reinfection, and reactivation stimuli influence memory inflation. We show that low titer infections induce “partial” memory inflation of both mCMV specific CD8 T-cells and antibody. We show further that reinfection with different strains can boost partial memory inflation. Finally, we show preliminary results suggesting that a single strong reactivation stimulus does not stimulate memory inflation. Altogether, our results suggest that while high titer primary infections can induce memory inflation, reinfections during the life of a host may be more important than previously appreciated. PMID:27870919

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

    PubMed Central

    Strangward, Patrick; Dandamudi, Durga B.; Coles, Jonathan A.; Villegas-Mendez, Ana; Gallego-Delgado, Julio; van Rooijen, Nico; Zindy, Egor; Rodriguez, Ana; Brewer, James M.; Couper, Kevin N.; Dustin, Michael L.

    2015-01-01

    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. PMID:26562533

  10. High Frequency of CD8 Positive Lymphocyte Infiltration Correlates with Lack of Lymph Node Involvement in Early Rectal Cancer

    PubMed Central

    Däster, Silvio; Eppenberger-Castori, Serenella; Hirt, Christian; Zlobec, Inti; Delko, Tarik; Nebiker, Christian A.; Soysal, Savas D.; Amicarella, Francesca; Iezzi, Giandomenica; Sconocchia, Giuseppe; Heberer, Michael; Lugli, Alessandro; Spagnoli, Giulio C.; Kettelhack, Christoph; Terracciano, Luigi; Oertli, Daniel; von Holzen, Urs; Tornillo, Luigi; Droeser, Raoul A.

    2014-01-01

    Aims. A trend towards local excision of early rectal cancers has prompted us to investigate if immunoprofiling might help in predicting lymph node involvement in this subgroup. Methods. A tissue microarray of 126 biopsies of early rectal cancer (T1 and T2) was stained for several immunomarkers of the innate and the adaptive immune response. Patients' survival and nodal status were analyzed and correlated with infiltration of the different immune cells. Results. Of all tested markers, only CD8 (P = 0.005) and TIA-1 (P = 0.05) were significantly more frequently detectable in early rectal cancer biopsies of node negative as compared to node positive patients. Although these two immunomarkers did not display prognostic effect “per se,” CD8+ and, marginally, TIA-1 T cell infiltration could predict nodal involvement in univariate logistic regression analysis (OR 0.994; 95% CI 0.992–0.996; P = 0.009 and OR 0.988; 95% CI 0.984–0.994; P = 0.05, resp.). An algorithm significantly predicting the nodal status in early rectal cancer based on CD8 together with vascular invasion and tumor border configuration could be calculated (P < 0.00001). Conclusion. Our data indicate that in early rectal cancers absence of CD8+ T-cell infiltration helps in predicting patients' nodal involvement. PMID:25609852

  11. RSV-specific airway resident memory CD8+ T cells and differential disease severity after experimental human infection

    PubMed Central

    Jozwik, Agnieszka; Habibi, Maximillian S.; Paras, Allan; Zhu, Jie; Guvenel, Aleks; Dhariwal, Jaideep; Almond, Mark; Wong, Ernie H. C.; Sykes, Annemarie; Maybeno, Matthew; Del Rosario, Jerico; Trujillo-Torralbo, Maria-Belen; Mallia, Patrick; Sidney, John; Peters, Bjoern; Kon, Onn Min; Sette, Alessandro; Johnston, Sebastian L.; Openshaw, Peter J.; Chiu, Christopher

    2015-01-01

    In animal models, resident memory CD8+ T (Trm) cells assist in respiratory virus elimination but their importance in man has not been determined. Here, using experimental human respiratory syncytial virus (RSV) infection, we investigate systemic and local virus-specific CD8+ T-cell responses in adult volunteers. Having defined the immunodominance hierarchy, we analyse phenotype and function longitudinally in blood and by serial bronchoscopy. Despite rapid clinical recovery, we note surprisingly extensive lower airway inflammation with persistent viral antigen and cellular infiltrates. Pulmonary virus-specific CD8+ T cells display a CD69+CD103+ Trm phenotype and accumulate to strikingly high frequencies into convalescence without continued proliferation. While these have a more highly differentiated phenotype, they express fewer cytotoxicity markers than in blood. Nevertheless, their abundance before infection correlates with reduced symptoms and viral load, implying that CD8+ Trm cells in the human lung can confer protection against severe respiratory viral disease when humoral immunity is overcome. PMID:26687547

  12. CD8+ T cells of chronic HCV-infected patients express multiple negative immune checkpoints following stimulation with HCV peptides.

    PubMed

    Barathan, Muttiah; Mohamed, Rosmawati; Vadivelu, Jamuna; Chang, Li Yen; Vignesh, Ramachandran; Krishnan, Jayalakshmi; Sigamani, Panneer; Saeidi, Alireza; Ram, M Ravishankar; Velu, Vijayakumar; Larsson, Marie; Shankar, Esaki M

    2017-03-01

    Hepatitis C virus (HCV)-specific CD4+ and CD8+ T cells are key to successful viral clearance in HCV disease. Accumulation of exhausted HCV-specific T cells during chronic infection results in considerable loss of protective functional immune responses. The role of T-cell exhaustion in chronic HCV disease remains poorly understood. Here, we studied the frequency of HCV peptide-stimulated T cells expressing negative immune checkpoints (PD-1, CTLA-4, TRAIL, TIM-3 and BTLA) by flow cytometry, and measured the levels of Th1/Th2/Th17 cytokines secreted by T cells by a commercial Multi-Analyte ELISArray™ following in vitro stimulation of T cells using HCV peptides and phytohemagglutinin (PHA). HCV peptide-stimulated CD4+ and CD8+ T cells of chronic HCV (CHC) patients showed significant increase of CTLA-4. Furthermore, HCV peptide-stimulated CD4+ T cells of CHC patients also displayed relatively higher levels of PD-1 and TRAIL, whereas TIM-3 was up-regulated on HCV peptide-stimulated CD8+ T cells. Whereas the levels of IL-10 and TGF-β1 were significantly increased, the levels of pro-inflammatory cytokines IL-2, TNF-α, IL-17A and IL-6 were markedly decreased in the T cell cultures of CHC patients. Chronic HCV infection results in functional exhaustion of CD4+ and CD8+ T cells likely contributing to viral persistence.

  13. CD8+ Treg cells suppress CD8+ T cell-responses by IL-10-dependent mechanism during H5N1 influenza virus infection.

    PubMed

    Zou, Qiang; Wu, Bing; Xue, Jia; Fan, Xiaoxu; Feng, Congcong; Geng, Shuang; Wang, Ming; Wang, Bin

    2014-01-01

    Although Treg-cell-mediated suppression during infection or autoimmunity has been described, functions of Treg cells during highly pathogenic avian influenza virus infection remain poorly characterized. Here we found that in Foxp3-GFP transgenic mice, CD8(+) Foxp3(+) Treg cells, but not CD4(+) Foxp3(+) Treg cells, were remarkably induced during H5N1 infection. In addition to expressing CD25, the CD8(+) Foxp3(+) Treg cells showed a high level of GITR and produced IL-10. In an adoptive transfer model, CD8(+) Treg cells suppressed CD8(+) T-cell responses and promoted H5N1 virus infection, resulting in enhanced mortality and increased virus load in the lung. Furthermore, in vitro neutralization of IL-10 and studies with IL-10R-deficient mice in vitro and in vivo demonstrated an important role for IL-10 production in the capacity of CD8(+) Treg cells to inhibit CD8(+) T-cell responses. Our findings identify a previously unrecognized role of CD8(+) Treg cells in the negative regulation of CD8(+) T-cell responses and suggest that modulation of CD8(+) Treg cells may be a therapeutic strategy to control H5N1 viral infection.

  14. TIL therapy broadens the tumor-reactive CD8(+) T cell compartment in melanoma patients.

    PubMed

    Kvistborg, Pia; Shu, Chengyi Jenny; Heemskerk, Bianca; Fankhauser, Manuel; Thrue, Charlotte Albæk; Toebes, Mireille; van Rooij, Nienke; Linnemann, Carsten; van Buuren, Marit M; Urbanus, Jos H M; Beltman, Joost B; Thor Straten, Per; Li, Yong F; Robbins, Paul F; Besser, Michal J; Schachter, Jacob; Kenter, Gemma G; Dudley, Mark E; Rosenberg, Steven A; Haanen, John B A G; Hadrup, Sine Reker; Schumacher, Ton N M

    2012-07-01

    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-induced T cell reactivity against a panel of 145 melanoma-associated CD8(+) T cell epitopes. Using this approach, we demonstrate that individual tumor-infiltrating lymphocyte cell products from melanoma patients contain unique patterns of reactivity against shared melanoma-associated antigens, and that the combined magnitude of these responses is surprisingly low. Importantly, TIL therapy increases the breadth of the tumor-reactive T cell compartment in vivo, and T cell reactivity observed post-therapy can almost in full be explained by the reactivity observed within the matched cell product. These results establish the value of high-throughput monitoring for the analysis of immuno-active therapeutics and suggest that the clinical efficacy of TIL therapy can be enhanced by the preparation of more defined tumor-reactive T cell products.

  15. TIL therapy broadens the tumor-reactive CD8+ T cell compartment in melanoma patients

    PubMed Central

    Kvistborg, Pia; Shu, Chengyi Jenny; Heemskerk, Bianca; Fankhauser, Manuel; Thrue, Charlotte Albæk; Toebes, Mireille; van Rooij, Nienke; Linnemann, Carsten; van Buuren, Marit M.; Urbanus, Jos H.M.; Beltman, Joost B.; thor Straten, Per; Li, Yong F.; Robbins, Paul F.; Besser, Michal J.; Schachter, Jacob; Kenter, Gemma G.; Dudley, Mark E.; Rosenberg, Steven A.; Haanen, John B.A.G.; Hadrup, Sine Reker; Schumacher, Ton N.M.

    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-induced T cell reactivity against a panel of 145 melanoma-associated CD8+ T cell epitopes. Using this approach, we demonstrate that individual tumor-infiltrating lymphocyte cell products from melanoma patients contain unique patterns of reactivity against shared melanoma-associated antigens, and that the combined magnitude of these responses is surprisingly low. Importantly, TIL therapy increases the breadth of the tumor-reactive T cell compartment in vivo, and T cell reactivity observed post-therapy can almost in full be explained by the reactivity observed within the matched cell product. These results establish the value of high-throughput monitoring for the analysis of immuno-active therapeutics and suggest that the clinical efficacy of TIL therapy can be enhanced by the preparation of more defined tumor-reactive T cell products. PMID:22754759

  16. CD4 and CD8 T cell responses to tumour-associated Epstein-Barr virus antigens in nasopharyngeal carcinoma patients.

    PubMed

    Lin, Xiaorong; Gudgeon, Nancy H; Hui, Edwin P; Jia, Hui; Qun, Xue; Taylor, Graham S; Barnardo, Martin C N M; Lin, C Kit; Rickinson, Alan B; Chan, Anthony T C

    2008-07-01

    Nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-associated tumour common in Southern Chinese populations, is a potentially important target for T cell-based immunotherapy. The tumour cells are HLA class I- and II-positive and express a limited subset of EBV latent proteins, namely the nuclear antigen EBNA1 and the latent membrane proteins LMP2 and (in some cases) LMP1. To ask whether the tumour develops in the presence of a potentially protective host response or in its absence, we set out to determine the prevailing levels of CD4+ and CD8+ T cell memory to these proteins in NPC patients at tumour diagnosis. We first screened healthy Chinese donors against Chinese strain EBNA1, LMP1 and LMP2 sequences in Elispot assays of interferon-gamma release and identified the immunodominant CD4+ and CD8+ epitope peptides presented by common Chinese HLA alleles. Then, comparing 60 patients with >70 healthy controls on peptide epitope mini-panels, we found that T cell memory to CD4 epitopes in all three proteins was unimpaired in the blood of patients at diagnosis. In most cases NPC patients also showed detectable responses to CD8 epitopes relevant to their HLA type, the one consistent exception being the absence in patients of a B*4001-restricted response to LMP2. We infer that NPC arises in patients whose prevailing levels of T cell memory to tumour-associated EBV proteins is largely intact; the therapeutic goal must therefore be to re-direct the existing memory repertoire more effectively against antigen-expressing tumour cells.

  17. Targeting CD8+ T-cell tolerance for cancer immunotherapy

    PubMed Central

    Jackson, Stephanie R; Yuan, Jinyun; Teague, Ryan M

    2014-01-01

    In the final issue of Science in 2013, the American Association of Science recognized progress in the field of cancer immunotherapy as the ‘Breakthrough of the Year.’ The achievements were actually twofold, owing to the early success of genetically engineered chimeric antigen receptors (CAR) and to the mounting clinical triumphs achieved with checkpoint blockade antibodies. While fundamentally very different, the common thread of these independent strategies is the ability to prevent or overcome mechanisms of CD8+ T-cell tolerance for improved tumor immunity. Here we discuss how circumventing T-cell tolerance has provided experimental insights that have guided the field of clinical cancer immunotherapy to a place where real breakthroughs can finally be claimed. PMID:25290416

  18. Targeting CD8+ T-cell tolerance for cancer immunotherapy.

    PubMed

    Jackson, Stephanie R; Yuan, Jinyun; Teague, Ryan M

    2014-01-01

    In the final issue of Science in 2013, the American Association of Science recognized progress in the field of cancer immunotherapy as the 'Breakthrough of the Year.' The achievements were actually twofold, owing to the early success of genetically engineered chimeric antigen receptors (CAR) and to the mounting clinical triumphs achieved with checkpoint blockade antibodies. While fundamentally very different, the common thread of these independent strategies is the ability to prevent or overcome mechanisms of CD8(+) T-cell tolerance for improved tumor immunity. Here we discuss how circumventing T-cell tolerance has provided experimental insights that have guided the field of clinical cancer immunotherapy to a place where real breakthroughs can finally be claimed.

  19. Expansion of CD8+ cells in autoimmune hemolytic anemia.

    PubMed

    Smirnova, S Ju; Sidorova, Ju V; Tsvetaeva, N V; Nikulina, O F; Biderman, B V; Nikulina, E E; Kulikov, S M; Sudarikov, A B

    2016-01-01

    Autoimmune hemolytic anemia (AIHA) is a rare blood disease associated with the production of auto-antibodies and autoimmune hemolysis. A critical role of B-cells in the development of AIHA has been demonstrated before. Here, we present the analysis of the clonal T-cell populations in patients with AIHA. Thirty-three patients with AIHA were included in this study. Thirteen patients with other anemias, 14 patients with other autoimmune conditions (SLE - 6, RA - 8) and 20 healthy donors were included in the study as a control group. The clonality of T-cell was evaluated by the assessment of the T-cell receptor gamma and beta chain gene rearrangements (TCRG and TCRB). The incidence of T-cell monoclonality detected in patients with AIHA was significantly higher compared to the control group. The persistence of T-cell clones did not correlate with the level of hemoglobin and other signs of remission or relapse and did not disappear after the therapy and clinical improvement (observation period was between 1 and 10 years). There was no correlation between the T-cell clonality and the gender, age, splenectomy, duration or severity of the disease. Fractionation of T-lymphocytes (CD4+, CD8+, CD4+25+) revealed that the monoclonal T-cells belonged to the CD8+ sub-population. We assume that besides a possible causative role of the T-cell clones in AIHA to autoimmune process, these clones do not directly participate in the development and maintenance of hemolysis. Most of the AIHA patients (48.5%) demonstrated a T-cell monoclonality, which requires monitoring and should be distinguished from T-cell tumors.

  20. Nonantigen specific CD8+ T suppressor lymphocytes originate from CD8+CD28- T cells and inhibit both T-cell proliferation and CTL function.

    PubMed

    Filaci, Gilberto; Fravega, Marco; Negrini, Simone; Procopio, Francesco; Fenoglio, Daniela; Rizzi, Marta; Brenci, Sabrina; Contini, Paola; Olive, Daniel; Ghio, Massimo; Setti, Maurizio; Accolla, Roberto S; Puppo, Francesco; Indiveri, Francesco

    2004-02-01

    Nonantigen specific CD8+ suppressor T lymphocytes (CD8+ Ts) inhibit T-cell proliferation of antigen-specific T lymphocytes. The impossibility to generate in vitro these cells has been correlated with the appearance of relapses in patients affected by autoimmune diseases, suggesting the involvement of these cells in immune regulation. This study was aimed to identify circulating precursors and to characterize the phenotype and mechanism of action of CD8+ Ts. We found that CD8+ Ts can be generated in vitro from CD8+CD28- T lymphocytes, but not from CD8+CD28+ T cells. A key role in their generation is played by monocytes that secrete interleukin-10 (IL-10) after granulocyte macrophage-colony-stimulating factor (GM-CSF) stimulation. Cell-to-cell direct interaction between CD8+CD28- T cells and monocytes does not play a role in the generation of CD8+ Ts. CD8+ Ts have a CD45RA+, CD27-, CCR7-, IL-10Ralpha+ phenotype and a TCR Vbeta chain repertoire overlapping that of autologous circulating CD8+ T cells. This phenotype is typical of T lymphocytes previously expanded due to antigen stimulation. Their suppressive effect on T-cell proliferation targets both antigen presenting cells, such as dendritic cells, and antigen-specific T lymphocytes, and is mediated by IL-10. CD8+ Ts suppress also the antigen-specific cytotoxic activity of CTL decreasing the expression of HLA class I molecules on target cells through IL-10 secretion. These findings can be helpful for the better understanding of immune regulatory circuits and for the definition of new pathogenic aspects in autoimmunity and tumor immunology.

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

    PubMed Central

    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. PMID:26498650

  2. Acute Virus Control Mediated by Licensed NK Cells Sets Primary CD8+ T Cell Dependence on CD27 Costimulation.

    PubMed

    Teoh, Jeffrey J; Gamache, Awndre E; Gillespie, Alyssa L; Stadnisky, Michael D; Yagita, Hideo; Bullock, Timothy N J; Brown, Michael G

    2016-12-01

    NK cells represent a critical first-line of immune defense against a bevy of viral pathogens, and infection can provoke them to mediate supportive and suppressive effects on virus-specific adaptive immunity. In mice expressing MHC class I D(k) (D(k)), a major murine CMV (MCMV) resistance factor and self-ligand of the inhibitory Ly49G2 (G2) receptor, licensed G2(+) NK cells provide essential host resistance against MCMV infection. Additionally G2(+) NK cell responses to MCMV increase the rate and extent of dendritic cell (DC) recovery, as well as early priming of CD8(+) T cell effectors in response to MCMV. However, relatively little is known about the NK cell effect on costimulatory ligand patterns displayed by DCs or on ensuing effector and memory T cell responses. In this study, we found that CD27-dependent CD8(+) T cell priming and differentiation are shaped by the efficiency of NK responses to virus infection. Surprisingly, differences in specific NK responses to MCMV in D(k)-disparate mice failed to distinguish early DC costimulatory patterns. Nonetheless, although CD27 deficiency did not impede licensed NK-mediated resistance, CD70 and CD27 were required to efficiently prime and regulate effector CD8(+) T cell differentiation in response to MCMV, which eventually resulted in biased memory T cell precursor formation in D(k) mice. In contrast, CD8(+) T cells accrued more slowly in non-D(k) mice and eventually differentiated into terminal effector cells regardless of CD27 stimulation. Disparity in this requirement for CD27 signaling indicates that specific virus control mediated by NK cells can shape DC costimulatory signals needed to prime CD8(+) T cells and eventual T cell fate decisions.

  3. CD8α+β− and CD8α+β+ plasmacytoid dendritic cells induce Foxp3+ regulatory T cells and prevent the induction of airway hyperreactivity

    PubMed Central

    Lombardi, Vincent; Speak, Anneliese O.; Kerzerho, Jérôme; Szely, Natacha; Akbari, Omid

    2012-01-01

    Dendritic cells (DCs) control the balance between protection against pathogens and tolerance to innocuous or self-antigens. Here, we demonstrate for the first time that mouse plasmacytoid DCs (pDCs) can be segregated into three distinct populations, exhibiting phenotypic and functional differences, according to their surface expression of CD8α or CD8β as CD8α−β−, CD8α+β− or CD8α+β+. In a mouse model of lung inflammation, adoptive transfer of CD8α+β− or CD8α+β+ pDCs prevents the development of airway hyperreactivity. The tolerogenic features of these subsets are associated with increased production of retinoic acid, which leads to the enhanced induction of Foxp3+ regulatory T cells compared to CD8α−β− pDCs. Our data thus identify subsets of pDCs with potent tolerogenic functions that may contribute to the maintenance of tolerance in mucosal sites such as the lungs. PMID:22472775

  4. IL-12-mediated STAT4 signaling and TCR signal strength cooperate in the induction of CD40L in human and mouse CD8+ T cells.

    PubMed

    Stark, Regina; Hartung, Anett; Zehn, Dietmar; Frentsch, Marco; Thiel, Andreas

    2013-06-01

    CD40L is one of the key molecules bridging the activation of specific T cells and the maturation of professional and nonprofessional antigen-presenting cells including B cells. CD4(+) T cells have been regarded as the major T-cell subset that expresses CD40L upon cognate activation; however, we demonstrate here that a putative CD8(+) helper T-cell subset expressing CD40L is induced in human and murine CD8(+) T cells in vitro and in mice immunized with antigen-pulsed dendritic cells. IL-12 and STAT4-mediated signaling was the major instructive cytokine signal boosting the ability of CD8(+) T cells to express CD40L both in vitro and in vivo. Additionally, TCR signaling strength modulated CD40L expression in CD8(+) T cells after primary differentiation in vitro as well as in vivo. The induction of CD40L in CD8(+) T cells regulated by IL-12 and TCR signaling may enable CD8(+) T cells to respond autonomously of CD4(+) T cells. Thus, we propose that under proinflammatory conditions, a self-sustaining positive feedback loop could facilitate the efficient priming of T cells stimulated by high affinity peptide displaying APCs.

  5. Defects in the Acquisition of Tumor-Killing Capability of CD8+ Cytotoxic T Cells in Streptozotocin-Induced Diabetic Mice

    PubMed Central

    Chen, Shu-Ching; Su, Yu-Chia; Lu, Ya-Ting; Ko, Patrick Chow-In; Chang, Pei-Yu; Lin, Hung-Ju; Ho, Hong-Nerng; Lai, Yo-Ping

    2014-01-01

    Emerging evidences have shown that diabetes mellitus not only raises risk but also heightens mortality rate of cancer. It is not clear, however, whether antitumor CD8+ cytotoxic T lymphocyte (CTL) response is down-modulated in diabetic hosts. We investigated the impact of hyperglycemia on CTLs' acquisition of tumor-killing capability by utilizing streptozotocin-induced diabetic (STZ-diabetic) mice. Murine diabetes was induced by intraperitoneal injection of STZ (200 mg/kg) in C57BL/6 mice, 2C-T cell receptor (TCR) transgenic and P14-TCR transgenic mice. The study found that, despite harboring intact proliferative capacity measured with CFSE labeling and MTT assay, STZ-diabetic CD8+ CTLs displayed impaired effector functions. After stimulation, STZ-diabetic CD8+ CTLs produced less perforin and TNFα assessed by intracellular staining, as well as expressed less CD103 protein. Furthermore, adoptive transfer of STZ-diabetic P14 CD8+ effector cells showed an insufficient recruitment to the B16.gp33 melanoma and inadequate production of perforin, granzyme B and TNFα determined by immunohistochemistry in the tumor milieu. As a result, STZ-diabetic CD8+ effector cells were neither able to eliminate tumor nor to improve survival of tumor-bearing mice. Taken together, our data suggest that CD8+ CTLs are crippled to infiltrate into tumors and thus fail to acquire tumor-killing capability in STZ-diabetic hosts. PMID:25390652

  6. Alterations in levels of CD28-/CD8+ suppressor cell precursor and CD45RO+/CD4+ memory T lymphocytes in the peripheral blood of multiple sclerosis patients.

    PubMed Central

    Crucian, B; Dunne, P; Friedman, H; Ragsdale, R; Pross, S; Widen, R

    1995-01-01

    A comprehensive peripheral blood immunophenotype analysis of 16 multiple sclerosis (MS) patients was performed by three-color flow cytometric analysis, and the results were compared with those for age-matched healthy controls. The cell subsets quantified included T cells (CD3+), B cells (CD19+), NK cells (CD56+), CD4+ and CD8+ T cells, cytotoxic (CD28+) and suppressor precursor (CD28-) CD8+ T cells, CD45RA+ and CD45RO+ T cells (CD4+ and CD8+), and CD5+ T and B cells. Analysis of MS patients' peripheral blood revealed essentially normal levels of total T, B, and NK cells. In agreement with results obtained by other investigators, it was found that MS patients had an increased CD4/CD8 ratio, primarily due to a decrease in CD8+ T cells. MS patients were found to have a significantly decreased level of suppressor precursor (CD28-) CD8+ T cells compared with that of controls but to have normal levels of cytotoxic (CD28+) CD8+ T cells. These data indicate that MS patients do not have a general decrease in CD8+ T cells but that they have a specific decrease in the suppressor precursor subset only and normal levels of cytotoxic CD8+ T cells. MS patients also had a significant increase in memory (CD45RO+) CD4+ T cells and displayed a trend towards a decrease in naive (CD45RA+) T cells in the peripheral blood. PMID:7697540

  7. A spatial view of the CD8+ T-cell response: the case of HCV.

    PubMed

    Racanelli, Vito; Leone, Patrizia; Grakoui, Arash

    2011-11-01

    In viral infections, a memory T-cell population comprises multiple subtypes of cells, distributed in diverse anatomic compartments and possibly re-circulating among them. Accordingly, memory T cells display distinct phenotypes and functions, depending on the nature of the infecting virus, the anatomic location of the infection, and the differences between the sites of active infection and T-cell collection. This paper explores the body compartments where virus-specific CD8(+) T cells have been found during chronic hepatitis C virus infection, describes the cells' memory qualities, and discusses how they are spatially regulated, in comparison with other human viral infections. Understanding the role of compartmentalization and diversity of HCV-specific memory T-cell subsets may be the key to developing effective immunotherapies.

  8. Pre-TCR signaling and CD8 gene bivalent chromatin resolution during thymocyte development.

    PubMed

    Harker, Nicola; Garefalaki, Anna; Menzel, Ursula; Ktistaki, Eleni; Naito, Taku; Georgopoulos, Katia; Kioussis, Dimitris

    2011-06-01

    The CD8 gene is silent in CD4(-)CD8(-) double-negative thymocytes, expressed in CD4(+)CD8(+) double-positive cells, and silenced in cells committing to the CD4(+) single-positive (SP) lineage, remaining active in the CD8(+) SP lineage. In this study, we show that the chromatin of the CD8 locus is remodeled in C57BL/6 and B6/J Rag1(-/-) MOM double-negative thymocytes as indicated by DNaseI hypersensitivity and widespread bivalent chromatin marks. Pre-TCR signaling coincides with chromatin bivalency resolution into monovalent activating modifications in double-positive and CD8 SP cells. Shortly after commitment to CD4 SP cell lineage, monovalent repressive characteristics and chromatin inaccessibility are established. Differential binding of Ikaros, NuRD, and heterochromatin protein 1α on the locus during these processes may participate in the complex regulation of CD8.

  9. Phenotypic and functional evaluation of CD3+CD4−CD8− T cells in human CD8 immunodeficiency

    PubMed Central

    Bernardo, Iván; Mancebo, Esther; Aguiló, Ignacio; Anel, Alberto; Allende, Luis M.; Guerra-Vales, Juan M.; Ruiz–Contreras, Jesús; Serrano, Antonio; Talayero, Paloma; de la Calle, Oscar; Gonzalez-Santesteban, Cecilia; Paz-Artal, Estela

    2011-01-01

    Background Human CD8 immunodeficiency is characterized by undetectable CD8+ lymphocytes and an increased population of CD4−CD8− (double negative) T lymphocytes. Design and Methods We hypothesized that the double negative subset corresponds to the cellular population that should express CD8 and is committed to the cytotoxic T lymphocyte lineage. To assess this, we determined the phenotype and function of peripheral blood mononuclear cells and/or magnetically isolated double negative T lymphocytes from two CD8-deficient patients. To analyze the expression and co-localization with different organelles, 293T cells were transfected with plasmids bearing wild-type or mutated CD8α. Results CD8α mutated protein was retained in the cytoplasm of transfected cells. The percentages of double negative cells in patients were lower than the percentages of CD8+ T cells in healthy controls. Double negative cells mostly had an effector or effector memory phenotype whereas naïve T cells were under-represented. A low concentration of T-cell receptor excision circles together with a skewed T-cell receptor-V repertoire were observed in the double negative population. These data suggest that, in the absence of CD8 co-receptor, the thymic positive selection functions suboptimally and a limited number of mature T-cell clones would emerge from the thymus. In vitro, the double negative cells showed a mild defect in cytotoxic function and decreased proliferative capacity. Conclusions It is possible that the double negative cells are major histocompatibility complex class-I restricted T cells with cytolytic function. These results show for the first time in humans that the presence of the CD8 co-receptor is dispensable for cytotoxic ability, but that it affects the generation of thymic precursors committed to the cytotoxic T lymphocyte lineage and the proliferation of mature cytotoxic T cells. PMID:21546492

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

    PubMed

    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.

  11. A recombinant fusion protein displaying murine and human MHC class I- and II-specific epitopes protects against Leishmania amazonensis infection.

    PubMed

    Martins, Vívian T; Lage, Daniela P; Duarte, Mariana C; Carvalho, Ana Maria R S; Costa, Lourena E; Mendes, Tiago A O; Vale, Danniele L; Menezes-Souza, Daniel; Roatt, Bruno M; Tavares, Carlos A P; Soto, Manuel; Coelho, Eduardo A F

    2017-03-01

    Tegumentary leishmaniasis (TL) constitutes a major public health problem with significant morbidity worldwide. Synthetic peptide-based vaccines are attractive candidates to protect against leishmaniasis, since T cell-specific epitopes can be delivery to antigen-presenting cells, leading to the generation of a Th1 cell-mediated immunity. In this context, the present study aims to evaluate the immunogenicity and protective efficacy of a vaccine composed of major histocompatibility complex class I and II-restricted epitopes derived from four Leishmania infantum proteins to protect mice against Leishmania amazonensis infection. This recombinant fusion protein was administered in BALB/c mice alone or with saponin. As controls, animals received saline or saponin. In the results, the administration of the recombinant protein plus saponin induced a specific IFN-γ, IL-12 and GM-CSF production, as well as high IgG2a isotype antibody levels, which protected mice against a challenge using L. amazonensis promastigotes. Lower parasite burden was found in the infected footpads, liver, spleen and draining lymph node of vaccinated mice, when compared to those from the control groups. In addition, protection was associated with a lower IL-4 and IL-10 response, which was accompanied by the antileishmanial nitrite production by spleen cells of the animals. Interestingly, the recombinant protein administered alone induced a partial protection against challenge. In conclusion, this study shows a new vaccine candidate based on T cell-specific epitopes that was able to induce protection against L. amazonensis infection.

  12. Functional and phenotypic characterization of peptide-vaccine-induced HCV-specific CD8+ T cells in healthy individuals and chronic hepatitis C patients.

    PubMed

    Schlaphoff, Verena; Klade, Christoph S; Jilma, Bernd; Jelovcan, Sandra B; Cornberg, Markus; Tauber, Erich; Manns, Michael P; Wedemeyer, Heiner

    2007-09-17

    Only very limited information on phenotype and function of vaccine-induced CD8+ T cells is available for humans. We investigated hepatitis C virus-specific CD8+ T cells after vaccination with the HCV peptide-vaccine IC41 which includes 5 MHC-class I and 3 MHC class-II-restricted epitopes. In healthy subjects, IC41 induced both HCV-specific central memory as well as effector CD8+ T cells which rapidly expanded upon antigen exposure in vitro. IFNgamma production was dependent on formulation of the synthetic peptides with the adjuvant poly-l-arginine. In chronic HCV patients, the frequency of HCV-specific CD8+ T cells increased after vaccination with a decline of CD45RA-positive effector memory cells in some but not all patients. Thus, this study suggests that HCV-specific memory cells can be induced by peptide vaccination and that a reversion of functional impaired phenotypes by therapeutic vaccination is possible in chronic HCV infection.

  13. Coexpression of PD-1, 2B4, CD160 and KLRG1 on exhausted HCV-specific CD8+ T cells is linked to antigen recognition and T cell differentiation.

    PubMed

    Bengsch, Bertram; Seigel, Bianca; Ruhl, Marianne; Timm, Jörg; Kuntz, Martin; Blum, Hubert E; Pircher, Hanspeter; Thimme, Robert

    2010-06-10

    Exhausted CD8+ T cell responses during chronic viral infections are defined by a complex expression pattern of inhibitory receptors. However, very little information is currently available about the coexpression patterns of these receptors on human virus-specific CD8+ T cells and their correlation with antiviral functions, T cell differentiation and antigen recognition. We addressed these important aspects in a cohort of 38 chronically HCV infected patients and found a coexpression of inhibitory receptors such as 2B4, CD160 and KLRG1 in association with PD-1 in about half of the HCV-specific CD8+ T cell responses. Importantly, this exhaustive phenotype was associated with low and intermediate levels of CD127 expression, an impaired proliferative capacity, an intermediate T cell differentiation stage and absence of sequence variations within the corresponding epitopes, indicating ongoing antigen triggering. In contrast, a low expression of inhibitory receptors by the remaining HCV-specific CD8+ T cells occurred in concert with a CD127hi phenotype, an early T cell differentiation stage and presence of viral sequence variations within the corresponding epitopes. In sum, these results suggest that T cell exhaustion contributes to the failure of about half of HCV-specific CD8+ T cell responses and that it is determined by a complex interplay of immunological (e.g. T cell differentiation) and virological (e.g. ongoing antigen triggering) factors.

  14. Mosaic vaccines elicit CD8+ T cell responses in monkeys that confer immune coverage of diverse HIV strains

    SciTech Connect

    Fischer, Will; Korber, Bette

    2009-01-01

    Creation of a successful HIV vaccine will require the development of a strategy to generate cellular immunity with sufficient cross-clade breadth to deal with the extreme genetic diversity of the virus. Polyvalent mosaic immunogens derived from in silica recombination of natural strains of HIV are designed to induce cellular immune responses that maximally cover the sequence diversity of circulating virus isolates. Immunization of rhesus monkeys with plasmid DNA and recombinant vaccinia virus vaccine constructs expressing either consensus immunogens or polyvalent mosaic immunogens elicited a CD4+ T lymphocyte-biased response with comparably broad epitope-specific total T lymphocyte specificities. However, immunization with the mosaic immunogens induced HIV-specific CD8+ T lymphocyte responses with markedly greater depth and breadth. Therefore, the use of polyvalent mosaic immunogens is a promising strategy for a global vaccine for HIV.

  15. An RNA nanoparticle vaccine against Zika virus elicits antibody and CD8+ T cell responses in a mouse model.

    PubMed

    Chahal, Jasdave S; Fang, Tao; Woodham, Andrew W; Khan, Omar F; Ling, Jingjing; Anderson, Daniel G; Ploegh, Hidde L

    2017-03-21

    The Zika virus (ZIKV) outbreak in the Americas and South Pacific poses a significant burden on human health because of ZIKV's neurotropic effects in the course of fetal development. Vaccine candidates against ZIKV are coming online, but immunological tools to study anti-ZIKV responses in preclinical models, particularly T cell responses, remain sparse. We deployed RNA nanoparticle technology to create a vaccine candidate that elicited ZIKV E protein-specific IgG responses in C57BL/6 mice as assayed by ELISA. Using this tool, we identified a unique H-2D(b)-restricted epitope to which there was a CD8(+) T cell response in mice immunized with our modified dendrimer-based RNA nanoparticle vaccine. These results demonstrate that this approach can be used to evaluate new candidate antigens and identify immune correlates without the use of live virus.

  16. Defining CD8+ T cells that provide the proliferative burst after PD-1 therapy

    PubMed Central

    Im, Se Jin; Hashimoto, Masao; Gerner, Michael Y.; Lee, Junghwa; Kissick, Haydn T.; Burger, Matheus C.; Shan, Qiang; Hale, J. Scott; Lee, Judong; Nasti, Tahseen H.; Sharpe, Arlene H.; Freeman, Gordon J.; Germain, Ronald N.; Nakaya, Helder I.; Xue, Hai-Hui; Ahmed, Rafi

    2017-01-01

    Chronic viral infections are characterized by a state of CD8+ T-cell dysfunction that is associated with expression of the programmed cell death 1 (PD-1) inhibitory receptor1–4. A better understanding of the mechanisms that regulate CD8+ T cell responses during chronic infection is required to improve immunotherapies that restore function in exhausted CD8+ T cells. Here we identify a population of virus-specific CD8+ T cells that proliferate after blockade of the PD-1 inhibitory pathway in mice chronically infected with lymphocytic choriomeningitis virus (LCMV). These LCMV-specific CD8+ T cells expressed the PD-1 inhibitory receptor but also expressed several costimulatory molecules such as ICOS and CD28. This CD8+ T cell subset was characterized by a unique gene signature that was related to that of CD4+ T follicular helper (TFH) cells, CD8+ T cell memory precursors and haematopoietic stem cell progenitors, but that was distinct from that of CD4+ TH1 cells and CD8+ terminal effectors. This CD8+ T cell population was found only in lymphoid tissues and resided predominantly in the T cell zones along with naïve CD8+ T cells. These PD-1+ CD8+ T cells resembled stem cells during chronic LCMV infection, undergoing self-renewal and also differentiating into the terminally exhausted CD8+ T cells that were present in both lymphoid and non-lymphoid tissues. The proliferative burst after PD-1 blockade came almost exclusively from this CD8+ T cell subset. Notably, the transcription factor TCF1 had a cell intrinsic and essential role in the generation of this CD8+ T cell subset. These findings provide a better understanding of T cell exhaustion and have implications in the optimization of PD-1-directed immunotherapy in chronic infections and cancer. PMID:27501248

  17. 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

    PubMed Central

    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

  18. Malaria DNA vaccine gp96NTD-CSP elicits both CSP-specific antibody and CD8(+) T cell response.

    PubMed

    Tan, Zhangping; Zhou, TaoLi; Zheng, Hong; Ding, Yan; Xu, Wenyue

    2015-06-01

    It is ideal for the pre-erythrocytic stage subunit vaccine to induce both CSP-specific antibody and CD8(+) T cell response. Here, we designed a novel malaria DNA vaccine gp96NTD-CSP, which was constructed by fusing the full-length of CSP with the N-terminal domain of gp96 that deleted the endoplasmic reticulum-localized motif KDEL, and investigated its protective efficacy. We found that the fusion protein gp96NTD-CSP was mainly distributed on the surface of eukaryotic cells after transfection and could be sensed as a "danger signal" by the host immune system. Interestingly, both liver parasite burden and parasitemia in mice immunized with gp96NTD-CSP were significantly lower than those in the mice immunized either with gp96NTD, CSP, or gp96NTD-SYVPSAEQI, which was constructed by fusing the CSP-specific CD8(+) T cell epitope with the N-terminal domain of gp96 deleted with KDEL. Consistently, both the level of CSP-specific antibody and the frequency of IFN-γ secreted-CSP-specific CD8(+) T cells were much higher in mice immunized with gp96NTD-CSP than those in the mice immunized either with gp96NTD, CSP, or gp96NTD-SYVPSAEQI. Our results suggest that the malaria DNA vaccine gp96NTD-CSP could induce both humoral and cellular immune responses, which is attributed to the adjuvant effect of gp96NTD and full-length CSP.

  19. Tumor-associated CD8+ T cell tolerance induced by bone marrow-derived immature myeloid cells.

    PubMed

    Kusmartsev, Sergei; Nagaraj, Srinivas; Gabrilovich, Dmitry I

    2005-10-01

    T cell tolerance is a critical element of tumor escape. However, the mechanism of tumor-associated T cell tolerance remains unresolved. Using an experimental system utilizing the adoptive transfer of transgenic T cells into naive recipients, we found that the population of Gr-1+ immature myeloid cells (ImC) from tumor-bearing mice was able to induce CD8+ T cell tolerance. These ImC accumulate in large numbers in spleens, lymph nodes, and tumor tissues of tumor-bearing mice and are comprised of precursors of myeloid cells. Neither ImC from control mice nor progeny of tumor-derived ImC, including tumor-derived CD11c+ dendritic cells, were able to render T cells nonresponsive. ImC are able to take up soluble protein in vivo, process it, and present antigenic epitopes on their surface and induce Ag-specific T cell anergy. Thus, this is a first demonstration that in tumor-bearing mice CD8+ T cell tolerance is induced primarily by ImC that may have direct implications for cancer immunotherapy.

  20. Tumor associated CD8+ T-cell tolerance induced by bone marrow derived immature myeloid cells1

    PubMed Central

    Kusmartsev, Sergei; Nagaraj, Srinivas; Gabrilovich, Dmitry I.

    2005-01-01

    T-cell tolerance is a critical element of tumor escape. However, the mechanism of tumor-associated T-cell tolerance remains unresolved. Using an experimental system employing the adoptive transfer of transgenic T cells into naïve recipients, we found that the population of Gr-1+ immature myeloid cells (ImC) from tumor-bearing mice was able to induce CD8+ T-cell tolerance. These ImC accumulate in large numbers in spleens, lymph nodes, and tumor tissues of tumor-bearing mice and are comprised of precursors of myeloid cells. Neither ImC from control mice nor progeny of tumor-derived ImC including tumor-derived CD11c+ DCs were able to render T cells non-responsive. ImC are able to take-up soluble protein in vivo, process it, and present antigenic epitopes on their surface and induce antigen-specific T-cell anergy. Thus, this is a first demonstration that in tumor-bearing mice CD8+ T-cell tolerance is induced primarily by ImC that may have direct implications for cancer immunotherapy. PMID:16177103

  1. Strong vaccine-induced CD8 T-cell responses have cytolytic function in a chimpanzee clearing HCV infection.

    PubMed

    Verstrepen, Babs E; Verschoor, Ernst J; Fagrouch, Zahra C; Mooij, Petra; de Groot, Natasja G; Bontrop, Ronald E; Bogers, Willy M; Heeney, Jonathan L; Koopman, Gerrit

    2014-01-01

    A single correlate of effective vaccine protection against chronic HCV infection has yet to be defined. In this study, we analyzed T-cell responses in four chimpanzees, immunized with core-E1-E2-NS3 and subsequently infected with HCV1b. Viral clearance was observed in one animal, while the other three became chronically infected. In the animal that cleared infection, NS3-specific CD8 T-cell responses were observed to be more potent in terms of frequency and polyfunctionality of cytokine producing cells. Unique to this animal was the presence of killing-competent CD8 T-cells, specific for NS3 1258-1272, being presented by the chimpanzee MHC class I molecule Patr-A*03∶01, and a high affinity recognition of this epitope. In the animals that became chronically infected, T-cells were able to produce cytokines against the same peptide but no cytolysis could be detected. In conclusion, in the animal that was able to clear HCV infection not only cytokine production was observed but also cytolytic potential against specific MHC class I/peptide-combinations.

  2. CDR3 clonotype and amino acid motif diversity of BV19 expressing circulating human CD8 T cells

    PubMed Central

    Yassai, Maryam B.; Demos, Wendy; Janczak, Teresa; Naumova, Elena N.; Gorski, Jack

    2015-01-01

    Generating a detailed description of human T cell repertoire diversity is an important goal in the study of human immunology. The circulation is the source of most T cells used for studies in humans. Here we use high throughput sequencing of TCR BV19 transcripts from CD8 T cells derived from unmanipulated PBMC from an older HLA-A2 individual to provide a quantitative and qualitative description of the clonotypic CDR3 nucleotide and amino acid composition of the TCR β-chain from this subset of circulating CD8 T cells. Aggregated samples from six time points spanning ~ 1.5 years were analyzed to smooth possible temporal fluctuation. BV19 encompasses the well studied RS-encoding clonotypes involved in recognition of the M158–66 epitope from influenza A in HLA-A2 individuals. The clonotype distribution was diverse, complex and self-similar. The amino acid composition was generally skewed in favor of glycines and there were specific amino acids observed at higher frequency at the NDN start position. The motif repertoire distribution was also diverse, complex and self-similar with respect to CDR3 length, NDN start and length. PMID:26593155

  3. Plasmodium vivax but Not Plasmodium falciparum Blood-Stage Infection in Humans Is Associated with the Expansion of a CD8+ T Cell Population with Cytotoxic Potential

    PubMed Central

    Burel, Julie G.; Apte, Simon H.; McCarthy, James S.; Doolan, Denise L.

    2016-01-01

    P. vivax and P. falciparum parasites display different tropism for host cells and induce very different clinical symptoms and pathology, suggesting that the immune responses required for protection may differ between these two species. However, no study has qualitatively compared the immune responses to P. falciparum or P. vivax in humans following primary exposure and infection. Here, we show that the two species differ in terms of the cellular immune responses elicited following primary infection. Specifically, P. vivax induced the expansion of a subset of CD8+ T cells expressing the activation marker CD38, whereas P. falciparum induced the expansion of CD38+ CD4+ T cells. The CD38+ CD8+ T cell population that expanded following P. vivax infection displayed greater cytotoxic potential compared to CD38- CD8+ T cells, and compared to CD38+ CD8+ T cells circulating during P. falciparum infection. We hypothesize that P. vivax infection leads to a stronger CD38+ CD8+ T cell activation because of its preferred tropism for MHC-I-expressing reticulocytes that, unlike mature red blood cells, can present antigen directly to CD8+ T cells. This study provides the first line of evidence to suggest an effector role for CD8+ T cells in P. vivax blood-stage immunity. It is also the first report of species-specific differences in the subset of T cells that are expanded following primary Plasmodium infection, suggesting that malaria vaccine development may require optimization according to the target parasite. Trial Registration anzctr.org.au ACTRN12612000814875; anzctr.org.au ACTRN12613000565741; anzctr.org.au ACTRN12613001040752; ClinicalTrials.gov NCT02281344; anzctr.org.au ACTRN12612001096842; anzctr.org.au ACTRN12613001008718 PMID:27930660

  4. Early HLA-B*57-Restricted CD8+ T Lymphocyte Responses Predict HIV-1 Disease Progression

    PubMed Central

    Ibarrondo, F. Javier; Sugar, Catherine A.; Hausner, Mary Ann; Shih, Roger; Ng, Hwee L.; Detels, Roger; Margolick, Joseph B.; Rinaldo, Charles R.; Phair, John; Jacobson, Lisa P.; Yang, Otto O.

    2012-01-01

    Although HLA-B*57 (B57) is associated with slow progression to disease following HIV-1 infection, B57 heterozygotes display a wide spectrum of outcomes, including rapid progression, viremic slow progression, and elite control. Efforts to identify differences between B57-positive (B57+) slow progressors and B57+ rapid progressors have largely focused on cytotoxic T lymphocyte (CTL) phenotypes and specificities during chronic stages of infection. Although CTL responses in the early months of infection are likely to be the most important for the long-term rate of HIV-1 disease progression, few data on the early CTL responses of eventual slow progressors have been available. Utilizing the Multicenter AIDS Cohort Study (MACS), we retrospectively examined the early HIV-1-specific CTL responses of 14 B57+ individuals whose time to development of disease ranged from 3.5 years to longer than 25 years after infection. In general, a greater breadth of targeting of epitopes from structural proteins, especially Gag, as well as of highly conserved epitopes from any HIV-1 protein, correlated with longer times until disease. The single elite controller in the cohort was an outlier on several correlations of CTL targeting and time until disease, consistent with reports that elite control is typically not achieved solely by protective HLA-mediated CTLs. When targeting of individual epitopes was analyzed, we found that early CTL responses to the IW9 (ISPRTLNAW) epitope of Gag, while generally subdominant, correlated with delayed progression to disease. This is the first study to identify early CTL responses to IW9 as a correlate of protection in persons with HLA-B*57. PMID:22811521

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

    PubMed Central

    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

  6. Clinically Relevant Reactivation of Polyomavirus BK (BKPyV) in HLA-A02-Positive Renal Transplant Recipients Is Associated with Impaired Effector-Memory Differentiation of BKPyV-Specific CD8+ T Cells

    PubMed Central

    Remmerswaal, Ester B. M.; Heutinck, Kirstin M.; ten Brinke, Anja; Feltkamp, Mariet C. W.; van der Weerd, Neelke C.; van der Pant, Karlijn A. M. I.; Bemelman, Frederike J.; van Lier, René A. W.; ten Berge, Ineke J. M.

    2016-01-01

    Polyomavirus BK (BKPyV) frequently reactivates in immunosuppressed renal transplant recipients (RTRs) and may lead to graft loss due to BKPyV-induced interstitial nephritis (BKVN). Little is known on the differentiation of CD8+ T cells targeting BKPyV in RTRs. Here we investigated whether BKPyV-specific CD8+ T cell differentiation differs in RTRs with varying degrees of BKPyV reactivation and/or BKVN. Using combinatorial encoding with tetramers carrying BKPyV major capsid protein (VP1) and large T antigen protein (LTAG) epitopes, we investigated CD8+ T cell responses to BKPyV in longitudinally obtained PBMC samples from 46 HLA-A02-positive RTRs and 20 healthy adults. We were also able to isolate BKPyV-specific CD8+ T cells from five renal allografts, two of which were affected by BKVN. Before transplantation, BKPyV-specific CD8+ T cells targeting VP1 and LTAG epitopes appeared predominantly as central-memory and CD27+/CD28+ effector-memory (TEM), and naïve-like PD-1-expressing cells, respectively. After viral reactivation, BKPyV-specific CD8+ T cells assumed CD28− TEM and TEMRA states in patients who were able to control BKPyV, whereas differentiation lagged behind in patients with severe viral reactivation or BKVN. Furthermore, VP1-specific CD69+/CD103+ tissue-resident memory (TRM) cells accumulated in BKVN-affected allografts but lacked signs of effector differentiation. In contrast, granzyme B-expressing effector cells were detected in allografts not affected by BKVN. In conclusion, effector-memory differentiation of BKPyV-specific CD8+ T cells in patients with high viral load or BKVN is impaired. Further characterization of the specific mechanisms behind this altered cellular differentiation is necessary to develop therapies that can prevent the emergence of BKVN. PMID:27723787

  7. Extracellular domains of CD8α and CD8ß subunits are sufficient for HLA class I restricted helper functions of TCR-engineered CD4(+) T cells.

    PubMed

    van Loenen, Marleen M; Hagedoorn, Renate S; de Boer, Renate; Falkenburg, J H Frederik; Heemskerk, Mirjam H M

    2013-01-01

    By gene transfer of HLA-class I restricted T-cell receptors (TCRs) (HLA-I-TCR) into CD8(+) as well as CD4(+) T-cells, both effector T-cells as well as helper T-cells can be generated. Since most HLA-I-TCRs function best in the presence of the CD8 co-receptor, the CD8αß molecule has to be co-transferred into the CD4(+) T-cells to engineer optimal helper T-cells. In this study, we set out to determine the minimal part of CD8αβ needed for optimal co-receptor function in HLA-I-TCR transduced CD4(+) T-cells. For this purpose, we transduced human peripheral blood derived CD4(+) T-cells with several HLA-class I restricted TCRs either with or without co-transfer of different CD8 subunits. We demonstrate that the co-transduced CD8αβ co-receptor in HLA-I-TCR transduced CD4(+) T-cells behaves as an adhesion molecule, since for optimal antigen-specific HLA class I restricted CD4(+) T-cell reactivity the extracellular domains of the CD8α and ß subunits are sufficient.

  8. Human CTLs to wild-type and enhanced epitopes of a novel prostate and breast tumor-associated protein, TARP, lyse human breast cancer cells.

    PubMed

    Oh, SangKon; Terabe, Masaki; Pendleton, C David; Bhattacharyya, Anu; Bera, Tapan K; Epel, Malka; Reiter, Yoram; Phillips, John; Linehan, W Marston; Kasten-Sportes, Claude; Pastan, Ira; Berzofsky, Jay A

    2004-04-01

    Vaccine therapy for prostate and breast cancer may have potential for treating these major causes of death in males and females, respectively. Critical to the development of tumor-specific vaccines is finding and characterizing novel antigens to be recognized by CD8(+) T cells. To define new CD8(+) T-cell tumor antigens, we determined two wild-type HLA-A2 epitopes from a recently found tumor-associated protein, TARP (T-cell receptor gamma alternate reading frame protein), expressed in prostate and breast cancer cells. We were also able to engineer epitope-enhanced peptides by sequence modifications. Both wild-type and enhanced epitopes induced peptide-specific CD8(+) T-cell responses in A2K(b) transgenic mice. In vitro restimulation of human CD8(+) T cells from a prostate cancer patient resulted in CD8(+) T cells reactive to the peptide epitopes that could lyse HLA-A2(+) human breast cancer cells (MCF-7) expressing TARP. Epitope-specific human CD8(+) T cells were also enumerated in patients' peripheral blood by tetramer staining. Our data suggest that HLA-A2-binding TARP epitopes and enhanced epitopes discovered in this study could be incorporated into a potential vaccine for both breast and prostate cancer.

  9. Dendritic cells drive memory CD8 T-cell homeostasis via IL-15 transpresentation

    PubMed Central

    Stonier, Spencer W.; Ma, Lisa J.; Castillo, Eliseo F.

    2008-01-01

    Interleukin-15 (IL-15) is crucial for the development of naive and memory CD8 T cells and is delivered through a mechanism called transpresentation. Previous studies showed that memory CD8 T cells require IL-15 transpresentation by an as yet unknown cell of hematopoietic origin. We hypothesized that dendritic cells (DCs) transpresent IL-15 to CD8 T cells, and we examined this by developing a transgenic model that limits IL-15 transpresentation to DCs. In this study, IL-15 transpresentation by DCs had little effect on restoring naive CD8 T cells but contributed to the development of memory-phenotype CD8 T cells. The generation of virus-specific, memory CD8 T cells was partially supported by IL-15Rα+ DCs through the preferential enhancement of a subset of KLRG-1+CD27− CD8 T cells. In contrast, these DCs were largely sufficient in driving normal homeostatic proliferation of established memory CD8 T cells, suggesting that memory CD8 T cells grow more dependent on IL-15 transpresentation by DCs. Overall, our study clearly supports a role for DCs in memory CD8 T-cell homeostasis but also provides evidence that other hematopoietic cells are involved in this function. The identification of DCs fulfilling this role will enable future studies to better focus on mechanisms regulating T-cell homeostasis. PMID:18812469

  10. Mcl-1 regulates effector and memory CD8 T-cell differentiation during acute viral infection.

    PubMed

    Kim, Eui Ho; Neldner, Brandon; Gui, Jingang; Craig, Ruth W; Suresh, M

    2016-03-01

    Mcl-1, an anti-apoptotic member of Bcl-2 family maintains cell viability during clonal expansion of CD8 T cells, but the cell intrinsic role of Mcl-1 in contraction of effectors or the number of memory CD8 T cells is unknown. Mcl-1 levels decline during the contraction phase but rebound to high levels in memory CD8 T cells. Therefore, by overexpressing Mcl-1 in CD8 T cells we asked whether limiting levels of Mcl-1 promote contraction of effectors and constrain CD8 T-cell memory. Mcl-1 overexpression failed to affect CD8 T-cell expansion, contraction or the magnitude of CD8 T-cell memory. Strikingly, high Mcl-1 levels enhanced mTOR phosphorylation and augmented the differentiation of terminal effector cells and effector memory CD8 T cells to the detriment of poly-cytokine-producing central memory CD8 T cells. Taken together, these findings provided unexpected insights into the role of Mcl-1 in the differentiation of effector and memory CD8 T cells.

  11. Dendritic cells drive memory CD8 T-cell homeostasis via IL-15 transpresentation.

    PubMed

    Stonier, Spencer W; Ma, Lisa J; Castillo, Eliseo F; Schluns, Kimberly S

    2008-12-01

    Interleukin-15 (IL-15) is crucial for the development of naive and memory CD8 T cells and is delivered through a mechanism called transpresentation. Previous studies showed that memory CD8 T cells require IL-15 transpresentation by an as yet unknown cell of hematopoietic origin. We hypothesized that dendritic cells (DCs) transpresent IL-15 to CD8 T cells, and we examined this by developing a transgenic model that limits IL-15 transpresentation to DCs. In this study, IL-15 transpresentation by DCs had little effect on restoring naive CD8 T cells but contributed to the development of memory-phenotype CD8 T cells. The generation of virus-specific, memory CD8 T cells was partially supported by IL-15Ralpha(+) DCs through the preferential enhancement of a subset of KLRG-1(+)CD27(-) CD8 T cells. In contrast, these DCs were largely sufficient in driving normal homeostatic proliferation of established memory CD8 T cells, suggesting that memory CD8 T cells grow more dependent on IL-15 transpresentation by DCs. Overall, our study clearly supports a role for DCs in memory CD8 T-cell homeostasis but also provides evidence that other hematopoietic cells are involved in this function. The identification of DCs fulfilling this role will enable future studies to better focus on mechanisms regulating T-cell homeostasis.

  12. Functional Signatures of Human CD4 and CD8 T Cell Responses to Mycobacterium tuberculosis.

    PubMed

    Prezzemolo, Teresa; Guggino, Giuliana; La Manna, Marco Pio; Di Liberto, Diana; Dieli, Francesco; Caccamo, Nadia

    2014-01-01

    contribute to the recruitment and activation of innate immune cells, like monocytes and granulocytes. Thus, while other antigen (Ag)-specific T cells such as CD8(+) T cells, natural killer (NK) cells, γδ T cells, and CD1-restricted T cells can also produce IFN-γ during Mtb infection, they cannot compensate for the lack of CD4(+) T cells. The detection of Ag-specific cytokine production by intracellular cytokine staining (ICS) and the use of flow cytometry techniques are a common routine that supports the studies aimed at focusing the role of the immune system in infectious diseases. Flow cytometry permits to evaluate simultaneously the presence of different cytokines that can delineate different subsets of cells as having "multifunctional/polyfunctional" profile. It has been proposed that polyfunctional T cells, are associated with protective immunity toward Mtb, in particular it has been highlighted that the number of Mtb-specific T cells producing a combination of IFN-γ, IL-2, and/or TNF-α may be correlated with the mycobacterial load, while other studies have associated the presence of this particular functional profile as marker of TB disease activity. Although the role of CD8 T cells in TB is less clear than CD4 T cells, they are generally considered to contribute to optimal immunity and protection. CD8 T cells possess a number of anti-microbial effector mechanisms that are less prominent or absent in CD4 Th1 and Th17 T cells. The interest in studying CD8 T cells that are either MHC-class Ia or MHC-class Ib-restricted, has gained more attention. These studies include the role of HLA-E-restricted cells, lung mucosal-associated invariant T-cells (MAIT), and CD1-restricted cells. Nevertheless, the knowledge about the role of CD8(+) T cells in Mtb infection is relatively new and recent studies have delineated that CD8 T cells, which display a functional profile termed "multifunctional," can be a better marker of protection in TB than CD4(+) T cells. Their effector

  13. Enforced OX40 Stimulation Empowers Booster Vaccines to Induce Effective CD4+ and CD8+ T Cell Responses against Mouse Cytomegalovirus Infection

    PubMed Central

    Panagioti, Eleni; Boon, Louis; Arens, Ramon; van der Burg, Sjoerd H.

    2017-01-01

    There is an imperative need for effective preventive vaccines against human cytomegalovirus as it poses a significant threat to the immunologically immature, causing congenital disease, and to the immune compromised including transplant recipients. In this study, we examined the efficacy of synthetic long peptides (SLPs) as a CD4+ and CD8+ T cell-eliciting preventive vaccine approach against mouse CMV (MCMV) infection. In addition, the use of agonistic OX40 antibodies to enhance vaccine efficacy was explored. Immunocompetent C57BL/6 mice were vaccinated in a prime-boost vaccination regiment with SLPs comprising various MHC class I- and II-restricted peptide epitopes of MCMV-encoded antigens. Enforced OX40 stimulation resulted in superior MCMV-specific CD4+ as CD8+ T cell responses when applied during booster SLP vaccination. Vaccination with a mixture of SLPs containing MHC class II epitopes and OX40 agonistic antibodies resulted in a moderate reduction of the viral titers after challenge with lytic MCMV infection. Markedly, the combination of SLP vaccines containing both MHC class I and II epitopes plus OX40 activation during booster vaccination resulted in polyfunctional (i.e., IFN-γ+, TNF+, IL-2+) CD4+ and CD8+ T cell responses that were even higher in magnitude when compared to those induced by the virus, and this resulted in the best containment of virus dissemination. Our results show that the induction of strong T cell responses can be a fundamental component in the design of vaccines against persistent viral infections. PMID:28265272

  14. Differences in hepatitis C virus (HCV)-specific CD8 T-cell phenotype during pegylated alpha interferon and ribavirin treatment are related to response to antiviral therapy in patients chronically infected with HCV.

    PubMed

    Caetano, Joana; Martinho, António; Paiva, Artur; Pais, Beatriz; Valente, Cristina; Luxo, Cristina

    2008-08-01

    CD8 T cells play a major role in antiviral immune responses. Their importance for progression to chronic hepatitis C and response to treatment are still unclear. To address these issues, hepatitis C virus (HCV)-specific CD8 T-cell responses were monitored, at the single-cell level, using HLA class I pentamers specific for HCV core and HCV NS3 epitopes, in 23 chronically infected patients during treatment with pegylated alpha interferon and ribavirin. Patients who presented a sustained-response to therapy had stronger HCV-specific CD8 T-cell responses at all time points studied. Moreover, there were clear differences in the phenotypes of these cells during therapy: in responder patients, terminally differentiated effector cells increased more rapidly, and their frequency was always higher than in nonresponder patients. Sustained-responder patients also showed a higher frequency of HCV-specific CD8 T cells producing cytotoxic factors. Overall, a late and inefficient differentiation process of HCV-specific CD8 T cells might be associated with lack of response to treatment. A better knowledge of the mechanisms underlying this impairment may be important for the development of new therapeutic strategies to maintain, restore, or increase CD8 T-cell effectiveness in chronic HCV infection.

  15. Differential mechanisms of memory CD8 T cell maintenance by individual myeloid cell types

    PubMed Central

    Frasca, Loredana; Stonier, Spencer W.; Overwijk, Willem W.; Schluns, Kimberly S.

    2010-01-01

    This study tested the hypothesis that individual myeloid subsets have a differential ability to maintain memory CD8 T cells via IL-15. Although DCs support IL-15-mediated homeostasis of memory CD8 T cells in vivo, whether various DC subsets and other myeloid cells similarly mediate homeostasis is unknown. Therefore, we studied the ability of different myeloid cells to maintain memory CD8 T cells in vitro. Using an in vitro cocoulture system that recapitulated known roles of DCs and IL-15 on memory CD8 T cells, all in vitro-derived or ex vivo-isolated DCs maintained CD8 T cells better than rIL-15 alone, and FLT-3L-DCs are the most efficient compared with GM-DCs, BM-derived macrophages, or freshly isolated DCs. Although FLT-3L-DCs were the least effective at inducing CD8 T cell proliferation, FLT-3L-DCs promoted better CD8 T cell survival and increased Bcl-2 and MCL-2 expression in CD8 T cells. T cell maintenance correlated only partially with DC expression of IL-15Rα and IL-15, suggesting that DCs provided additional support signals. Indeed, in the absence of IL-15 signals, CD70/CD27 further supported CD8 T cell maintenance. IFN-α enhanced CD70 expression by DCs, resulting in increased proliferation of CD8 T cells. Overall, this study supports our hypothesis by demonstrating that specific DC subtypes had a greater capacity to support memory CD8 T cell maintenance and did so through different mechanisms. Furthermore, this study shows that IL-15 trans-presentation can work in conjunction with other signals, such as CD70/CD27 interactions, to mediate CD8 T cell homeostasis efficiently. PMID:20354106

  16. Expression of CD8alpha identifies a distinct subset of effector memory CD4+ T lymphocytes.

    PubMed

    Macchia, Iole; Gauduin, Marie-Claire; Kaur, Amitinder; Johnson, R Paul

    2006-10-01

    Circulating CD4+ CD8+ T lymphocytes have been described in the peripheral blood of humans and several animal species. However, the origin and functional properties of these cells remain poorly understood. In the present study, we evaluated the frequency, phenotype and function of peripheral CD4+ CD8+ T cells in rhesus macaques. Two distinct populations of CD4+ CD8+ T cells were identified: the dominant one was CD4hi CD8lo and expressed the CD8alphaalpha homodimer, while the minor population was CD4lo CD8hi and expressed the CD8alphabeta heterodimer. The majority of CD4hi CD8alphalo T cells exhibited an activated effector/memory phenotype (CCR5lo CD7- CD28- HLA-DR+) and expressed relatively high levels of granzyme B. Intracellular cytokine staining assays demonstrated that the frequency of cytomegalovirus-specific T cells was enriched five-fold in CD4hi CD8alphalo T cells compared to single-positive CD4+ T cells, whereas no consistent enrichment was observed for simian immunodeficiency virus (SIV)-specific T cells. Cross-sectional studies of SIV-infected animals demonstrated that the frequency of CD4hi CD8alphalo T cells was lower in wild-type SIV-infected animals compared to uninfected controls, although prospective studies of SIV-infected animals demonstrated depletion of CD4hi CD8alphalo lymphocytes only in a subset of animals. Taken together, these data suggest that CD4+ T cells expressing CD8alpha represent an effector/memory subset of CD4+ T cells and that this cell population can be depleted during the course of SIV infection.

  17. Peripheral Proinsulin Expression Controls Low-Avidity Proinsulin-Reactive CD8 T Cells in Type 1 Diabetes.

    PubMed

    Thayer, Terri C; Pearson, James A; De Leenheer, Evy; Hanna, Stephanie J; Boldison, Joanne; Davies, Joanne; Tsui, Adrian; Ahmed, Sartaj; Easton, Peter; Siew, Lai Khai; Wen, Li; Wong, F Susan

    2016-11-01

    Low-avidity autoreactive CD8 T cells (CTLs) escape from thymic negative selection, and peripheral tolerance mechanisms are essential for their regulation. We report the role of proinsulin (PI) expression on the development and activation of insulin-specific CTLs in the NOD mouse model of type 1 diabetes. We studied insulin B-chain-specific CTL from different T-cell receptor transgenic mice (G9Cα(-/-)) expressing normal PI1 and PI2 or altered PI expression levels. In the absence of PI2 (Ins2(-/-)), CTL in pancreatic lymph nodes (PLNs) were more activated, and male G9Cα(-/-) mice developed T1D. Furthermore, when the insulin-specific CTLs developed in transgenic mice lacking their specific PI epitope, the CTLs demonstrated increased cytotoxicity and proliferation in vitro and in vivo in the PLNs after adoptive transfer into NOD recipients. Dendritic cell-stimulated proliferation of insulin-specific T cells was reduced in the presence of lymph node stromal cells (LNSCs) from NOD mice but not from mice lacking the PI epitope. Our study shows that LNSCs regulate CTL activation and suggests that exposure to PI in the periphery is very important in maintenance of tolerance of autoreactive T cells. This is relevant for human type 1 diabetes and has implications for the use of antigen-specific therapy in tolerance induction.

  18. Broad HIV-1 inhibition in vitro by vaccine-elicited CD8+ T cells in African adults

    PubMed Central

    Mutua, Gaudensia; Farah, Bashir; Langat, Robert; Indangasi, Jackton; Ogola, Simon; Onsembe, Brian; Kopycinski, Jakub T; Hayes, Peter; Borthwick, Nicola J; Ashraf, Ambreen; Dally, Len; Barin, Burc; Tillander, Annika; Gilmour, Jill; De Bont, Jan; Crook, Alison; Hannaman, Drew; Cox, Josephine H; Anzala, Omu; Fast, Patricia E; Reilly, Marie; Chinyenze, Kundai; Jaoko, Walter; Hanke, Tomáš; HIV-CORE 004 study group, the

    2016-01-01

    We are developing a pan-clade HIV-1 T-cell vaccine HIVconsv, which could complement Env vaccines for prophylaxis and be a key to HIV cure. Our strategy focuses vaccine-elicited effector T-cells on functionally and structurally conserved regions (not full-length proteins and not only epitopes) of the HIV-1 proteome, which are common to most global variants and which, if mutated, cause a replicative fitness loss. Our first clinical trial in low risk HIV-1-negative adults in Oxford demonstrated the principle that naturally mostly subdominant epitopes, when taken out of the context of full-length proteins/virus and delivered by potent regimens involving combinations of simian adenovirus and poxvirus modified vaccinia virus Ankara, can induce robust CD8+ T cells of broad specificities and functions capable of inhibiting in vitro HIV-1 replication. Here and for the first time, we tested this strategy in low risk HIV-1-negative adults in Africa. We showed that the vaccines were well tolerated and induced high frequencies of broadly HIVconsv-specific plurifunctional T cells, which inhibited in vitro viruses from four major clades A, B, C, and D. Because sub-Saharan Africa is globally the region most affected by HIV-1/AIDS, trial HIV-CORE 004 represents an important stage in the path toward efficacy evaluation of this highly rational and promising vaccine strategy. PMID:27617268

  19. Induction of potent CD8+ T-cell responses by novel biodegradable nanoparticles carrying human immunodeficiency virus type 1 gp120.

    PubMed

    Wang, Xin; Uto, Tomofumi; Akagi, Takami; Akashi, Mitsuru; Baba, Masanori

    2007-09-01

    The mainstream of recent anti-AIDS vaccines is a prime/boost approach with multiple doses of the target DNA of human immunodeficiency virus type 1 (HIV-1) and recombinant viral vectors. In this study, we have attempted to construct an efficient protein-based vaccine using biodegradable poly(gamma-glutamic acid) (gamma-PGA) nanoparticles (NPs), which are capable of inducing potent cellular immunity. A significant expansion of CD8+ T cells specific to the major histocompatibility complex class I-restricted gp120 epitope was observed in mice intranasally immunized once with gp120-carrying NPs but not with gp120 alone or gp120 together with the B-subunit of cholera toxin. Both the gp120-encapsulating and -immobilizing forms of NPs could induce antigen-specific spleen CD8+ T cells having a functional profile of cytotoxic T lymphocytes. Long-lived memory CD8+ T cells could also be elicited. Although a substantial decay in the effector memory T cells was observed over time in the immunized mice, the central memory T cells remained relatively constant from day 30 to day 238 after immunization. Furthermore, the memory CD8+ T cells rapidly expanded with boosting with the same immunogen. In addition, gamma-PGA NPs were found to be a much stronger inducer of antigen-specific CD8+ T-cell responses than nonbiodegradable polystyrene NPs. Thus, gamma-PGA NPs carrying various HIV-1 antigens may have great potential as a novel priming and/or boosting tool in current vaccination regimens for the induction of cellular immune responses.

  20. IFN-{gamma}+ CD8+ T Lymphocytes: Possible Link Between Immune and Radiation Responses in Tumor-Relevant Hypoxia

    SciTech Connect

    De Ridder, Mark Jiang Heng; Esch, Gretel van; Law, Kalun; Monsaert, Christinne; Berge, Dirk L. van den; Verellen, Dirk; Verovski, Valeri N.; Storme, Guy A.

    2008-07-01

    Activated T lymphocytes are known to kill tumor cells by triggering cytolytic mechanisms; however, their ability to enhance radiation responses remains unclear. This study examined the radiosensitizing potential of mouse CD8+ T cells, obtained by T-cell-tailored expansion and immunomagnetic purification. Activated CD8+ T cells displayed an interferon (IFN)-{gamma}+ phenotype and enhanced by 1.8-fold the radiosensitivity of EMT-6 tumor cells in 1% oxygen, which modeled tumor-relevant hypoxia. Radiosensitization was counteracted by neutralizing IFN-{gamma} or by blocking the inducible isoform of nitric oxide synthase, thus delineating the immune-tumor cell interaction through the IFN-{gamma} secretion pathway. Reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and fluorescence-activated cell sorter data in agreement detected downregulation of the IFN-{gamma} gene by hypoxia, which caused IFN-{gamma} deficiency next to radioresistance. Therefore, immune and radiation responses are likely to be allied in the hypoxic tumor microenvironment, and CD8+ T cells may bridge immunostimulatory and radiosensitizing strategies.

  1. Human CD8+ T Cells in Asthma: Possible Pathways and Roles for NK-Like Subtypes

    PubMed Central

    Lourenço, Olga; Fonseca, Ana Mafalda; Taborda-Barata, Luis

    2016-01-01

    Asthma affects approximately 300 million people worldwide and is the most common chronic lung disease, which usually is associated with bronchial inflammation. Most research has focused upon the role of CD4+ T cells, and relatively few studies have addressed the phenotypic and functional roles of CD8+ T cell types and subtypes. Human NK-like CD8+ T cells may involve cells that have been described as CD8+CD28−, CD8+CD28−CD57+, CD8+CD27−, or CD8+ effector memory (TEM) cells, among other. However, most of the data that are available regarding these various cell types were obtained in murine models did not thoroughly characterize these cells with phenotypically or functionally or did not involve asthma-related settings. Nevertheless, one may conceptualize three principal roles for human NK-like CD8+ T cells in asthma: disease-promoting, regulatory, and/or tissue repair. Although evidence for some of these roles is scarce, it is possible to extrapolate some data from overlapping or related CD8+ T cell phenotypes, with caution. Clearly, further research is warranted, namely in terms of thorough functional and phenotypic characterization of human NK-like CD8+ T cells in human asthma of varying severity. PMID:28066445

  2. Chinese goose (Anser cygnoides) CD8a: cloning, tissue distribution and immunobiological in splenic mononuclear cells.

    PubMed

    Zhao, Qiurong; Liu, Fei; Chen, Shun; Yan, Xiaoling; Qi, Yulin; Wang, Mingshu; Jia, Renyong; Zhu, Dekang; Liu, Mafeng; Chen, Xiaoyue; Cheng, Anchun

    2013-10-25

    CD8 molecule is a cell membrane glycoprotein, which plays an important role in cell-mediated immunity. Here, we identified Chinese goose CD8α (goCD8α) gene for the first time. The full-length cDNA of goCD8α is 1459bp in length and contains a 711bp open reading frame. Phylogenetic analysis shows that the waterfowl CD8α formed a monophyletic group. Semi-quantitative RT-PCR analysis showed that transcripts of goCD8α mRNA were high in the immune-related organs and mucosal immune system in gosling, and high in thymus and spleen comparing to other immune-related tissues in goose. The obvious increase of CD8α expression was observed in spleen of acute new type gosling viral enteritis virus (NGVEV) infected bird, while the increase of CD8α were observed in the thymus, bursa of fabricius, and cecum of chronic infected bird. The CD8α mRNA transcription level in spleen mononuclear cells was significantly up-regulated when stimulated by phytohemagglutinin, but not by lipopolysaccharide in vitro.

  3. Genetic determinism in the relationship between human CD4+ and CD8+ T lymphocyte populations?

    PubMed

    Ahmadi, K R; Hall, M A; Norman, P; Vaughan, R W; Snieder, H; Spector, T D; Lanchbury, J S

    2001-11-01

    The adaptive immune system in mammals acts in a coordinated manner to eliminate environmentally derived pathogens. Humans, mice and rats show within species variation in the levels and ratios of their peripheral CD4+ and CD8+ T cells and to a significant degree this variation is under the control of polymorphic genes. Whether genes act separately to specify CD4+ and CD8+ subpopulation levels or whether CD8+ variation is controlled through gene and environmental action on CD4+ cells or vice versa, is not known. We use a quantitative modelling approach in identical and non-identical female human twins to delineate the lines of control which act upon and between CD4+ and CD8+ subsets. The major findings of the study are: (1) genetic variation controls CD8+ T cell levels through two major routes-the first is via an effect on CD4+ T cells which accounts for the observed co-variation between CD4+ and CD8+ T cells, the second is through direct action on CD8+ T cell levels. (2) No evidence of a gene effect from CD8+ T cells on CD4+ cells is observed. Our findings have implications for the evolution of the complex defence system of which CD4+ and CD8+ T cells are a crucial part and encourage further work towards locating common pleiotropic quantitative trait loci responsible for variation in numbers of T cells.

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

    PubMed Central

    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

  5. Loss of DNAM-1 contributes to CD8+ T cell exhaustion in chronic HIV-1 infection

    PubMed Central

    Cella, Marina; Presti, Rachel; Vermi, William; Lavender, Kerry; Turnbull, Emma; Ochsenbauer-Jambor, Christina; Kappes, John C.; Ferrari, Guido; Kessels, Lisa; Williams, Ian; McMichael, Andrew J.; Haynes, Barton F.; Borrow, Persephone; Colonna, Marco

    2011-01-01

    Summary The hallmark of chronic viral infections is a progressive exhaustion of antigen specific CD8+ T cells that leads to persisting viral replication. It is generally believed that exhaustion is a consequence of the accumulation of multiple inhibitory receptors on CD8+ T cells that makes them dysfunctional. Here we show that during human chronic HIV-1 infection a CD8+ T cell positive costimulatory pathway mediated by DNAM-1 is also disrupted. Thus, DNAM-1 downregulation on CD8+ T cells aggravates the impairment of CTL effector function in chronic HIV-1 infection. PMID:20201043

  6. Cutting edge: innate memory CD8+ T cells are distinct from homeostatic expanded CD8+ T cells and rapidly respond to primary antigenic stimuli.

    PubMed

    Huang, Weishan; Hu, Jianfang; August, Avery

    2013-03-15

    Innate memory phenotype (IMP) CD8(+) T cells are nonconventional αβ T cells exhibiting features of innate immune cells and are significantly increased in the absence of ITK. Their developmental path and function are not clear. In this study, we show hematopoietic MHC class I (MHCI)-dependent generation of Ag-specific IMP CD8(+) T cells using bone marrow chimeras. Wild-type bone marrow gives rise to IMP CD8(+) T cells in MHCI(-/-) recipients, resembling those in Itk(-/-) mice, but distinct from those derived via homeostatic proliferation, and independent of recipient thymus. In contrast, MHCI(-/-) bone marrow does not lead to IMP CD8(+) T cells in wild-type recipients. OTI IMP CD8(+) T cells generated via this method exhibited enhanced early response to Ag without prior primary stimulation. Our findings suggest a method to generate Ag-specific "naive" CD8(+) IMP T cells, as well as demonstrate that they are not homeostatic proliferation cells and can respond promptly in an Ag-specific fashion.

  7. Comparison of naïve and central memory derived CD8(+) effector cell engraftment fitness and function following adoptive transfer.

    PubMed

    Wang, Xiuli; Wong, ChingLam W; Urak, Ryan; Taus, Ellie; Aguilar, Brenda; Chang, Wen-Chung; Mardiros, Armen; Budde, Lihua E; Brown, Christine E; Berger, Carolina; Forman, Stephen J; Jensen, Michael C

    Human CD8(+) effector T cells derived from CD45RO(+)CD62L(+) precursors enriched for central memory (TCM) precursors retain the capacity to engraft and reconstitute functional memory upon adoptive transfer, whereas effectors derived from CD45RO(+)CD62L(-) precursors enriched for effector memory precursors do not. Here we sought to compare the engraftment fitness and function of CD8(+) effector T cells derived from CD45RA(+)CD62L(+) precursors enriched for naïve and stem cell memory precursors (TN/SCM) with that of TCM. We found that cytotoxic T cells (CTLs) derived from TCM transcribed higher levels of CD28, FOS, INFγ, Eomesodermin (Eomes), and lower levels of BCL2L11, maintained higher levels of phosphorylated AKT, and displayed enhanced sensitivity to the proliferative and anti-apoptotic effects of γ-chain cytokines compared to CTLs derived from TN/SCM. Higher frequencies of CTLs derived from TCM retained CD28 expression and upon activation secreted higher levels of IL-2. In NOD/Scid IL-2RγC(null) mice, CD8(+) TCM derived CTLs engrafted to higher frequencies in response to human IL-15 and mounted robust proliferative responses to an immunostimulatory vaccine. Similarly, CD8(+) TCM derived CD19CAR(+) CTLs exhibited superior antitumor potency following adoptive transfer compared to their CD8(+) TN/SCM derived counterparts. These studies support the use of TCM enriched cell products for adoptive therapy of cancer.

  8. Dynamics of SIV-specific CXCR5+ CD8 T cells during chronic SIV infection

    PubMed Central

    Mylvaganam, Geetha H.; Rios, Daniel; Abdelaal, Hadia M.; Iyer, Smita; Tharp, Gregory; Mavinger, Maud; Hicks, Sakeenah; Chahroudi, Ann; Ahmed, Rafi; Bosinger, Steven E.; Williams, Ifor R.; Skinner, Pamela J.; Velu, Vijayakumar

    2017-01-01

    A significant challenge to HIV eradication is the elimination of viral reservoirs in germinal center (GC) T follicular helper (Tfh) cells. However, GCs are considered to be immune privileged for antiviral CD8 T cells. Here, we show a population of simian immunodeficiency virus (SIV)-specific CD8 T cells express CXCR5 (C-X-C chemokine receptor type 5, a chemokine receptor required for homing to GCs) and expand in lymph nodes (LNs) following pathogenic SIV infection in a cohort of vaccinated macaques. This expansion was greater in animals that exhibited superior control of SIV. The CXCR5+ SIV-specific CD8 T cells demonstrated enhanced polyfunctionality, restricted expansion of antigen-pulsed Tfh cells in vitro, and possessed a unique gene expression pattern related to Tfh and Th2 cells. The increase in CXCR5+ CD8 T cells was associated with the presence of higher frequencies of SIV-specific CD8 T cells in the GC. Following TCR-driven stimulation in vitro, CXCR5+ but not CXCR5– CD8 T cells generated both CXCR5+ as well as CXCR5– cells. However, the addition of TGF-β to CXCR5– CD8 T cells induced a population of CXCR5+ CD8 T cells, suggesting that this cytokine may be important in modulating these CXCR5+ CD8 T cells in vivo. Thus, CXCR5+ CD8 T cells represent a unique subset of antiviral CD8 T cells that expand in LNs during chronic SIV infection and may play a significant role in the control of pathogenic SIV infection. PMID:28159893

  9. IL-15 regulates memory CD8+ T cell O-glycan synthesis and affects trafficking

    PubMed Central

    Nolz, Jeffrey C.; Harty, John T.

    2014-01-01

    Memory and naive CD8+ T cells exhibit distinct trafficking patterns. Specifically, memory but not naive CD8+ T cells are recruited to inflamed tissues in an antigen-independent manner. However, the molecular mechanisms that regulate memory CD8+ T cell trafficking are largely unknown. Here, using murine models of infection and T cell transfer, we found that memory but not naive CD8+ T cells dynamically regulate expression of core 2 O-glycans, which interact with P- and E-selectins to modulate trafficking to inflamed tissues. Following infection, antigen-specific effector CD8+ T cells strongly expressed core 2 O-glycans, but this glycosylation pattern was lost by most memory CD8+ T cells. After unrelated infection or inflammatory challenge, memory CD8+ T cells synthesized core 2 O-glycans independently of antigen restimulation. The presence of core 2 O-glycans subsequently directed these cells to inflamed tissue. Memory and naive CD8+ T cells exhibited the opposite pattern of epigenetic modifications at the Gcnt1 locus, which encodes the enzyme that initiates core 2 O-glycan synthesis. The open chromatin configuration in memory CD8+ T cells permitted de novo generation of core 2 O-glycans in a TCR-independent, but IL-15–dependent, manner. Thus, IL-15 stimulation promotes antigen-experienced memory CD8+ T cells to generate core 2 O-glycans, which subsequently localize them to inflamed tissues. These findings suggest that CD8+ memory T cell trafficking potentially can be manipulated to improve host defense and immunotherapy. PMID:24509081

  10. Description of an ectothermic TCR coreceptor, CD8 alpha, in rainbow trout.

    PubMed

    Hansen, J D; Strassburger, P

    2000-03-15

    We have cloned the first CD8 alpha gene from an ectothermic source using a degenerate primer for Ig superfamily V domains. Similar to homologues in higher vertebrates, the rainbow trout CD8 alpha gene encodes a 204-aa mature protein composed of two extracellular domains including an Ig superfamily V domain and hinge region. Differing from mammalian CD8 alpha V domains, lower vertebrate (trout and chicken) sequences do not contain the extra cysteine residue (C strand) involved in the abnormal intrachain disulfide bridging within the CD8 alpha V domain of mice and rats. The trout membrane proximal hinge region contains the two essential cysteine residues involved in CD8 dimerization (alpha alpha or alpha beta) and threonine, serine, and proline residues which may be involved in multiple O-linked glycosylation events. Although the transmembrane region is well conserved in all CD8 alpha sequences analyzed to date, the putative trout cytoplasmic region differs and, in fact, lacks the consensus p56lck motif common to other CD8 alpha sequences. We then determined that the trout CD8 alpha genomic structure is similar to that of humans (six exons) but differs from that of mice (five exons). Additionally, Northern blotting and RT-PCR demonstrate that trout CD8 alpha is expressed at high levels within the thymus and at weaker levels in the spleen, kidney, intestine, and peripheral blood leukocytes. Finally, we show that trout CD8 alpha can be expressed on the surface of cells via transfection. Together, our results demonstrate that the basic structure and expression of CD8 alpha has been maintained for more than 400 million years of evolution.

  11. TIGIT and PD-1 impair tumor antigen–specific CD8+ T cells in melanoma patients

    PubMed Central

    Chauvin, Joe-Marc; Pagliano, Ornella; Fourcade, Julien; Sun, Zhaojun; Wang, Hong; Sander, Cindy; Kirkwood, John M.; Chen, Tseng-hui Timothy; Maurer, Mark; Korman, Alan J.; Zarour, Hassane M.

    2015-01-01

    T cell Ig and ITIM domain (TIGIT) is an inhibitory receptor expressed by activated T cells, Tregs, and NK cells. Here, we determined that TIGIT is upregulated on tumor antigen–specific (TA-specific) CD8+ T cells and CD8+ tumor-infiltrating lymphocytes (TILs) from patients with melanoma, and these TIGIT-expressing CD8+ T cells often coexpress the inhibitory receptor PD-1. Moreover, CD8+ TILs from patients exhibited downregulation of the costimulatory molecule CD226, which competes with TIGIT for the same ligand, supporting a TIGIT/CD226 imbalance in metastatic melanoma. TIGIT marked early T cell activation and was further upregulated by T cells upon PD-1 blockade and in dysfunctional PD-1+TIM-3+ TA-specific CD8+ T cells. PD-1+TIGIT+, PD-1–TIGIT+, and PD-1+TIGIT– CD8+ TILs had similar functional capacities ex vivo, suggesting that TIGIT alone, or together with PD-1, is not indicative of T cell dysfunction. However, in the presence of TIGIT ligand–expressing cells, TIGIT and PD-1 blockade additively increased proliferation, cytokine production, and degranulation of both TA-specific CD8+ T cells and CD8+ TILs. Collectively, our results show that TIGIT and PD-1 regulate the expansion and function of TA-specific CD8+ T cells and CD8+ TILs in melanoma patients and suggest that dual TIGIT and PD-1 blockade should be further explored to elicit potent antitumor CD8+ T cell responses in patients with advanced melanoma. PMID:25866972

  12. CD3+CD8+CD28− T Lymphocytes in Patients with Lupus Nephritis

    PubMed Central

    Krajewska, Magdalena

    2016-01-01

    The results of studies on the CD3+CD8+CD28− cells in SLE are inconsistent since several analyses describe CD3+CD8+CD28− as either immunosuppressive or cytotoxic. The aim of this study is to inquire whether the quantitative changes of CD3+CD8+CD28− T lymphocytes subpopulation are related to the clinical status of patients with lupus nephritis. Evaluation of Foxp3 expression on CD3+CD8+CD28− cells may shed some light on functional properties of these cells. 54 adult SLE patients and 19 sex and age matched healthy volunteers were enrolled in the study. There were 15 patients in inactive (SLEDAI ≤ 5) and 39 in active (SLEDAI > 5) phase of disease. We determined absolute count of CD3+CD8+CD28− and CD3+CD8+CD28−Foxp3+ subpopulations by flow cytometry. We observed a statistically significant increase in absolute count and percentage of CD3+CD8+CD28− in SLE patients compared to HC (p < 0.001). Moreover there was significant positive correlation between increasing absolute count of CD3+CD8+CD28− cells and disease activity measured by SLEDAI (rs = 0.281, p = 0.038). Active LN patients had increased absolute count of CD3+CD8+CD28− cells compared to HC. Positive correlation of CD3+CD8+CD28− number with disease activity, and lack of Foxp3 expression on these cells, suggests that CD3+CD8+CD28− lymphocytes might be responsible for an increased proinflammatory response in the exacerbation of SLE. PMID:27446964

  13. Dynamics of SIV-specific CXCR5+ CD8 T cells during chronic SIV infection.

    PubMed

    Mylvaganam, Geetha H; Rios, Daniel; Abdelaal, Hadia M; Iyer, Smita; Tharp, Gregory; Mavinger, Maud; Hicks, Sakeenah; Chahroudi, Ann; Ahmed, Rafi; Bosinger, Steven E; Williams, Ifor R; Skinner, Pamela J; Velu, Vijayakumar; Amara, Rama R

    2017-02-21

    A significant challenge to HIV eradication is the elimination of viral reservoirs in germinal center (GC) T follicular helper (Tfh) cells. However, GCs are considered to be immune privileged for antiviral CD8 T cells. Here, we show a population of simian immunodeficiency virus (SIV)-specific CD8 T cells express CXCR5 (C-X-C chemokine receptor type 5, a chemokine receptor required for homing to GCs) and expand in lymph nodes (LNs) following pathogenic SIV infection in a cohort of vaccinated macaques. This expansion was greater in animals that exhibited superior control of SIV. The CXCR5+ SIV-specific CD8 T cells demonstrated enhanced polyfunctionality, restricted expansion of antigen-pulsed Tfh cells in vitro, and possessed a unique gene expression pattern related to Tfh and Th2 cells. The increase in CXCR5+ CD8 T cells was associated with the presence of higher frequencies of SIV-specific CD8 T cells in the GC. Following TCR-driven stimulation in vitro, CXCR5+ but not CXCR5- CD8 T cells generated both CXCR5+ as well as CXCR5- cells. However, the addition of TGF-β to CXCR5- CD8 T cells induced a population of CXCR5+ CD8 T cells, suggesting that this cytokine may be important in modulating these CXCR5+ CD8 T cells in vivo. Thus, CXCR5+ CD8 T cells represent a unique subset of antiviral CD8 T cells that expand in LNs during chronic SIV infection and may play a significant role in the control of pathogenic SIV infection.

  14. CD4/CD8 ratio and CD8 counts predict CD4 response in HIV-1-infected drug naive and in patients on cART

    PubMed Central

    Sauter, Rafael; Huang, Ruizhu; Ledergerber, Bruno; Battegay, Manuel; Bernasconi, Enos; Cavassini, Matthias; Furrer, Hansjakob; Hoffmann, Matthias; Rougemont, Mathieu; Günthard, Huldrych F; Held, Leonhard

    2016-01-01

    Abstract Plasma HIV viral load is related to declining CD4 lymphocytes. The extent to which CD8 cells, in addition to RNA viral load, predict the depletion of CD4 cells is not well characterized so far. We examine if CD8 cell count is a prognostic factor for CD4 cell counts during an HIV infection. A longitudinal analysis is conducted using data from the Swiss HIV cohort study collected between January 2000 and October 2014. Linear mixed regression models were applied to observations from HIV-1-infected treatment naive patients (NAIVE) and cART-treated patients to predict the short-term evolution of CD4 cell counts. For each subgroup, it was quantified to which extent CD8 cell counts or CD4/CD8 ratios are prognostic factors for disease progression. In both subgroups, 2500 NAIVE and 8902 cART patients, past CD4 cells are positively (P < 0.0001) and past viral load is negatively (P < 0.0001) associated with the outcome. Including additionally past CD8 cell counts improves the fit significantly (P < 0.0001) and increases the marginal explained variation 31.7% to 40.7% for the NAIVE and from 44.1% to 50.7% for the cART group. The past CD4/CD8 ratio (instead of the past CD8 level) is positively associated with the outcome, increasing the explained variation further to 41.8% for NAIVE and 51.9% for cART. PMID:27759638

  15. Molecular profiling of CD8 T cells in autochthonous melanoma identifies Maf as driver of exhaustion

    PubMed Central

    Giordano, Marilyn; Henin, Coralie; Maurizio, Julien; Imbratta, Claire; Bourdely, Pierre; Buferne, Michel; Baitsch, Lukas; Vanhille, Laurent; Sieweke, Michael H; Speiser, Daniel E; Auphan-Anezin, Nathalie; Schmitt-Verhulst, Anne-Marie; Verdeil, Grégory

    2015-01-01

    T cells infiltrating neoplasms express surface molecules typical of chronically virus-stimulated T cells, often termed “exhausted” T cells. We compared the transcriptome of “exhausted” CD8 T cells infiltrating autochthonous melanomas to those of naïve and acutely stimulated CD8 T cells. Despite strong similarities between transcriptional signatures of tumor- and virus-induced exhausted CD8 T cells, notable differences appeared. Among transcriptional regulators, Nr4a2 and Maf were highly overexpressed in tumor-exhausted T cells and significantly upregulated in CD8 T cells from human melanoma metastases. Transduction of murine tumor-specific CD8 T cells to express Maf partially reproduced the transcriptional program associated with tumor-induced exhaustion. Upon adoptive transfer, the transduced cells showed normal homeostasis but failed to accumulate in tumor-bearing hosts and developed defective anti-tumor effector responses. We further identified TGFβ and IL-6 as main inducers of Maf expression in CD8 T cells and showed that Maf-deleted tumor-specific CD8 T cells were much more potent to restrain tumor growth in vivo. Therefore, the melanoma microenvironment contributes to skewing of CD8 T cell differentiation programs, in part by TGFβ/IL-6-mediated induction of Maf. PMID:26139534

  16. IL-15 promotes activation and expansion of CD8+ T cells in HIV-1 infection

    PubMed Central

    Younes, Souheil-Antoine; Freeman, Michael L.; Mudd, Joseph C.; Shive, Carey L.; Reynaldi, Arnold; Estes, Jacob D.; Deleage, Claire; Lucero, Carissa; Anderson, Jodi; Schacker, Timothy W.; Davenport, Miles P.; McCune, Joseph M.; Hunt, Peter W.; Lee, Sulggi A.; Debernardo, Robert L.; Jacobson, Jeffrey M.; Canaday, David H.; Sekaly, Rafick-Pierre; Sieg, Scott F.; Lederman, Michael M.

    2016-01-01

    In HIV-1–infected patients, increased numbers of circulating CD8+ T cells are linked to increased risk of morbidity and mortality. Here, we identified a bystander mechanism that promotes CD8 T cell activation and expansion in untreated HIV-1–infected patients. Compared with healthy controls, untreated HIV-1–infected patients have an increased population of proliferating, granzyme B+, CD8+ T cells in circulation. Vβ expression and deep sequencing of CDR3 revealed that in untreated HIV-1 infection, cycling memory CD8 T cells possess a broad T cell repertoire that reflects the repertoire of the resting population. This suggests that cycling is driven by bystander activation, rather than specific antigen exposure. Treatment of peripheral blood mononuclear cells with IL-15 induced a cycling, granzyme B+ phenotype in CD8+ T cells. Moreover, elevated IL-15 expression in the lymph nodes of untreated HIV-1–infected patients correlated with circulating CD8+ T cell counts and was normalized in these patients following antiretroviral therapy. Together, these results suggest that IL-15 drives bystander activation of CD8+ T cells, which predicts disease progression in untreated HIV-1–infected patients and suggests that elevated IL-15 may also drive CD8+ T cell expansion that is linked to increased morbidity and mortality in treated patients. PMID:27322062

  17. Phenotypical and functional alterations of CD8 regulatory T cells in primary biliary cirrhosis

    PubMed Central

    Bernuzzi, Francesca; Fenoglio, Daniela; Battaglia, Florinda; Fravega, Marco; Gershwin, M. Eric; Indiveri, Francesco; Ansari, Aftab A.; Podda, Mauro; Invernizzi, Pietro; Filaci, Gilberto

    2011-01-01

    The mechanisms that lead to loss of tolerance in autoimmune disease have remained both elusive and diverse, including both genetic predisposition and generic dysregulation of critical mononuclear cell subsets. In primary biliary cirrhosis (PBC), patients exhibit a multilineage response to the E2 component of pyruvate dehydrogenase involving antibody as well as autoreactive CD4 and CD8 responses. Recent data from murine models of PBC have suggested that a critical mechanism of biliary destruction is mediated by liver-infiltrating CD8 cells. Further, the number of autoreactive liver-infiltrating CD4 and CD8 cells is significantly higher in liver than blood in patients with PBC. Based on this data, we have studied the frequencies and phenotypic characterization of both CD4 and CD8 regulatory T cell components in both patients with PBC and age–sex matched controls. Our data is striking and indicate that CD8 Treg populations from PBC patients, but not controls, have significant phenotypic alterations, including increased expression of CD127 and reduced CD39. Furthermore, in vitro induction of CD8 Tregs by incubation with IL10 is significantly reduced in PBC patients. Importantly, the frequencies of circulating CD4+CD25+ and CD8+ and CD28− T cell subpopulations are not significantly different between patients and controls. In conclusion, these data identify the CD8 Treg subset as a regulatory T cell subpopulation altered in patients with PBC. PMID:20638239

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

    PubMed Central

    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-2b) 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

  19. Pathogenic CD8 T Cells in Multiple Sclerosis and Its Experimental Models

    PubMed Central

    Huseby, Eric S.; Huseby, Priya G.; Shah, Shivanee; Smith, Rebecca; Stadinski, Brian D.

    2012-01-01

    A growing body of evidence suggests that autoreactive CD8 T cells contribute to the disease process in multiple sclerosis (MS). Lymphocytes in MS plaques are biased toward the CD8 lineage, and MS patients harbor CD8 T cells specific for multiple central nervous system (CNS) antigens. Currently, there are relatively few experimental model systems available to study these pathogenic CD8 T cells in vivo. However, the few studies that have been done characterizing the mechanisms used by CD8 T cells to induce CNS autoimmunity indicate that several of the paradigms of how CD4 T cells mediate CNS autoimmunity do not hold true for CD8 T cells or for patients with MS. Thus, myelin-specific CD4 T cells are likely to be one of several important mechanisms that drive CNS disease in MS patients. The focus of this review is to highlight the current models of pathogenic CNS-reactive CD8 T cells and the molecular mechanisms these lymphocytes use when causing CNS inflammation and damage. Understanding how CNS-reactive CD8 T cells escape tolerance induction and induce CNS autoimmunity is critical to our ability to propose and test new therapies for MS. PMID:22566945

  20. CD152 (CTLA-4) regulates effector functions of CD8+ T lymphocytes by repressing Eomesodermin.

    PubMed

    Hegel, Johannes K; Knieke, Karin; Kolar, Paula; Reiner, Steven L; Brunner-Weinzierl, Monika C

    2009-03-01

    CD8(+) T lymphocytes are required for effective host defense against pathogens and also for mediating effector responses against uncontrolled proliferating self-tissues. In this study, we determine that individual CD8(+) T cells are tightly controlled in their effector functions by CD152 (CTLA-4). We demonstrate that signals induced by CD152 reduce the frequency of IFN-gamma and granzyme B expressing CD8(+) T cells independently of the transcription factors T-bet or cKrox by selectively inhibiting accumulation of Eomesodermin mRNA and protein. Ectopic expression of Eomesodermin reversed the CD152-mediated inhibition of effector molecule production. Additionally, enhanced cytotoxicity of individual CD8(+) T cells differentiated in the absence of CD152 signaling was determined in vivo. These novel insights extend our understanding of how immune responses of CD8(+) T cells are selectively modulated.

  1. 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

    PubMed Central

    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

  2. Krüppel-like factor KLF10 regulates transforming growth factor receptor II expression and TGF-β signaling in CD8+ T lymphocytes.

    PubMed

    Papadakis, Konstantinos A; Krempski, James; Reiter, Jesse; Svingen, Phyllis; Xiong, Yuning; Sarmento, Olga F; Huseby, April; Johnson, Aaron J; Lomberk, Gwen A; Urrutia, Raul A; Faubion, William A

    2015-03-01

    KLF10 has recently elicited significant attention as a transcriptional regulator of transforming growth factor-β1 (TGF-β1) signaling in CD4(+) T cells. In the current study, we demonstrate a novel role for KLF10 in the regulation of TGF-β receptor II (TGF-βRII) expression with functional relevance in antiviral immune response. Specifically, we show that KLF10-deficient mice have an increased number of effector/memory CD8(+) T cells, display higher levels of the T helper type 1 cell-associated transcription factor T-bet, and produce more IFN-γ following in vitro stimulation. In addition, KLF10(-/-) CD8(+) T cells show enhanced proliferation in vitro and homeostatic proliferation in vivo. Freshly isolated CD8(+) T cells from the spleen of adult mice express lower levels of surface TGF-βRII (TβRII). Congruently, in vitro activation of KLF10-deficient CD8(+) T cells upregulate TGF-βRII to a lesser extent compared with wild-type (WT) CD8(+) T cells, which results in attenuated Smad2 phosphorylation following TGF-β1 stimulation compared with WT CD8(+) T cells. Moreover, we demonstrate that KLF10 directly binds to the TGF-βRII promoter in T cells, leading to enhanced gene expression. In vivo viral infection with Daniel's strain Theiler's murine encephalomyelitis virus (TMEV) also led to lower expression of TGF-βRII among viral-specific KLF10(-/-) CD8(+) T cells and a higher percentage of IFN-γ-producing CD8(+) T cells in the spleen. Collectively, our data reveal a critical role for KLF10 in the transcriptional activation of TGF-βRII in CD8(+) T cells. Thus, KLF10 regulation of TGF-βRII in this cell subset may likely play a critical role in viral and tumor immune responses for which the integrity of the TGF-β1/TGF-βRII signaling pathway is crucial.

  3. The small heat shock protein 27 is a key regulator of CD8+ CD57+ lymphocyte survival.

    PubMed

    Wood, Karen L; Voss, Oliver H; Huang, Qin; Parihar, Arti; Mehta, Neeraj; Batra, Sanjay; Doseff, Andrea I

    2010-05-15

    Differences in CD8(+)CD57(-) and CD8(+)CD57(+) lymphocyte lifespan have been documented. Lower numbers and shorter lifespan are characteristic of CD8(+)CD57(+) in normal individuals. However, CD8(+)CD57(+) are expanded in certain disease states including T cell large granular leukemia and other hematologic malignancies. The mechanisms responsible for the differences in CD8(+)CD57(-) and CD8(+)CD57(+) lifespan remain elusive. In this study, we demonstrate that the small heat shock protein (Hsp) 27 is a key regulator of CD8(+)CD57(+) lymphocyte lifespan. We found that Hsp27 expression is significantly lower in CD8(+)CD57(+) than in CD8(+)CD57(-) lymphocytes. In contrast, Hsp60 and Hsp70 are expressed at comparable levels. Unlike other antiapoptotic Bcl-2-like molecules, the expression of Hsp27 tightly correlates with CD8(+)CD57(+) and CD8(+)CD57(-) lifespan. We demonstrate that Hsp27 overexpression in CD8(+)CD57(+) lymphocytes to levels found normally in CD8(+)CD57(-) lymphocytes decreased apoptosis. Accordingly, silencing of Hsp27 in CD8(+)CD57(-) lymphocytes increased apoptosis. Collectively these results demonstrate that Hsp27 is a critical regulator of normal CD8(+)CD57(+) lifespan supporting its use as a marker of lifespan in this lineage, and suggest a mechanism responsible for the decreased apoptosis and clonal expansion characteristic of certain disease states.

  4. NK Cells Help Induce Anti-Hepatitis B Virus CD8+ T Cell Immunity in Mice.

    PubMed

    Zheng, Meijuan; Sun, Rui; Wei, Haiming; Tian, Zhigang

    2016-05-15

    Although recent clinical studies demonstrate that NK cell function is impaired in hepatitis B virus (HBV)-persistent patients, whether or how NK cells play a role in anti-HBV adaptive immunity remains to be explored. Using a mouse model mimicking acute HBV infection by hydrodynamic injection of an HBV plasmid, we observed that although serum hepatitis B surface Ag and hepatitis B envelope Ag were eliminated within 3 to 4 wk, HBV might persist for >8 wk in CD8(-/-) mice and that adoptive transfer of anti-HBV CD8(+) T cells restored the ability to clear HBV in HBV-carrier Rag1(-/-) mice. These results indicate that CD8(+) T cells are critical in HBV elimination. Furthermore, NK cells increased IFN-γ production after HBV plasmid injection, and NK cell depletion led to significantly increased HBV persistence along with reduced frequency of hepatitis B core Ag-specific CD8(+) T cells. Adoptive transfer of IFN-γ-sufficient NK cells restored donor CD8(+) T cell function, indicating that NK cells positively regulated CD8(+) T cells via secreting IFN-γ. We also observed that NK cell depletion correlated with decreased effector memory CD8(+) T cell frequencies. Importantly, adoptive transfer experiments showed that NK cells were involved in anti-HBV CD8(+) T cell recall responses. Moreover, DX5(+)CD49a(-) conventional, but not DX5(-)CD49a(+) liver-resident, NK cells were involved in improving CD8(+) T cell responses against HBV. Overall, the current study reveals that NK cells, especially DX5(+)CD49a(-) conventional NK cells, promote the antiviral activity of CD8(+) T cell responses via secreting IFN-γ in a mouse model mimicking acute HBV infection.

  5. An MHC class Ib-restricted CD8+ T cell response to lymphocytic choriomeningitis virus.

    PubMed

    Chen, Lili; Jay, David C; Fairbanks, Jared D; He, Xiao; Jensen, Peter E

    2011-12-15

    Conventional MHC class Ia-restricted CD8(+) T cells play a dominant role in the host response to virus infections, but recent studies indicate that T cells with specificity for nonclassical MHC class Ib molecules may also participate in host defense. To investigate the potential role of class Ib molecules in anti-viral immune responses, K(b-/-)D(b-/-)CIITA(-/-) mice lacking expression of MHC class Ia and class II molecules were infected with lymphocytic choriomeningitis virus (LCMV). These animals have a large class Ib-selected CD8(+) T cell population and they were observed to mediate partial (but incomplete) virus clearance during acute LCMV infection as compared with K(b-/-)D(b-/-)β(2)-microglobulin(-/-) mice that lack expression of both MHC class Ia and class Ib molecules. Infection was associated with expansion of splenic CD8(+) T cells and induction of granzyme B and IFN-γ effector molecules in CD8(+) T cells. Partial virus clearance was dependent on CD8(+) cells. In vitro T cell restimulation assays demonstrated induction of a population of β(2)-microglobulin-dependent, MHC class Ib-restricted CD8(+) T cells with specificity for viral Ags and yet to be defined nonclassical MHC molecules. MHC class Ib-restricted CD8(+) T cell responses were also observed after infection of K(b-/-)D(b-/-)mice despite the low number of CD8(+) T cells in these animals. Long-term infection studies demonstrated chronic infection and gradual depletion of CD8(+) T cells in K(b-/-)D(b-/-)CIITA(-/-) mice, demonstrating that class Ia molecules are required for viral clearance. These findings demonstrate that class Ib-restricted CD8(+) T cells have the potential to participate in the host immune response to LCMV.

  6. Prevalent CD8+ T cell response against one peptide/MHC complex in autoimmune diabetes

    PubMed Central

    Anderson, Brad; Park, Bjung-Ju; Verdaguer, Joan; Amrani, Abdelaziz; Santamaria, Pere

    1999-01-01

    Spontaneous autoimmune diabetes in nonobese diabetic (NOD) mice is the result of a CD4+ and CD8+ T cell-dependent autoimmune process directed against the pancreatic beta cells. CD8+ T cells play a critical role in the initiation and progression of diabetes, but the specificity and diversity of their antigenic repertoire remain unknown. Here, we define the structure of a peptide mimotope that elicits the proliferation, cytokine secretion, differentiation, and cytotoxicity of a diabetogenic H-2Kd-restricted CD8+ T cell specificity (NY8.3) that uses a T cell receptor α (TCRα) rearrangement frequently expressed by CD8+ T cells propagated from the earliest insulitic lesions of NOD mice (Vα17-Jα42 elements, often joined by the N-region sequence M-R-D/E). Stimulation of splenic CD8+ T cells from single-chain 8.3-TCRβ-transgenic NOD mice with this mimotope leads to preferential expansion of T cells bearing an endogenously derived TCRα chain identical to the one used by their islet-associated CD8+ T cells, which is also identical to the 8.3-TCRα sequence. Cytotoxicity assays using islet-derived CD8+ T cell clones from nontransgenic NOD mice as effectors and peptide-pulsed H-2Kd-transfected RMA-S cells as targets indicate that nearly half of the CD8+ T cells recruited to islets in NOD mice specifically recognize the same peptide/H-2Kd complex. This work demonstrates that beta cell-reactive CD8+ T cells mount a prevalent response against a single peptide/MHC complex and provides one peptide ligand for CD8+ T cells in autoimmune diabetes. PMID:10430939

  7. Protective and Pathogenic Roles of CD8+ T Lymphocytes in Murine Orientia tsutsugamushi Infection

    PubMed Central

    Hauptmann, Matthias; Kolbaum, Julia; Lilla, Stefanie; Wozniak, David; Gharaibeh, Mohammad; Fleischer, Bernhard; Keller, Christian A.

    2016-01-01

    T cells are known to contribute to immune protection against scrub typhus, a potentially fatal infection caused by the obligate intracellular bacterium Orientia (O.) tsutsugamushi. However, the contribution of CD8+ T cells to protection and pathogenesis during O. tsutsugamushi infection is still unknown. Using our recently developed BALB/c mouse model that is based on footpad inoculation of the human-pathogenic Karp strain, we show that activated CD8+ T cells infiltrate spleen and lung during the third week of infection. Depletion of CD8+ T cells with monoclonal antibodies resulted in uncontrolled pathogen growth and mortality. Adoptive transfer of CD8+ T cells from infected animals protected naïve BALB/c mice from lethal outcome of intraperitoneal challenge. In C57Bl/6 mice, the pulmonary lymphocyte compartment showed an increased percentage of CD8+ T cells for at least 135 days post O. tsutsugamushi infection. Depletion of CD8+ T cells at 84 days post infection caused reactivation of bacterial growth. In CD8+ T cell-deficient beta 2-microglobulin knockout mice, bacterial replication was uncontrolled, and all mice succumbed to the infection, despite higher serum IFN-γ levels and stronger macrophage responses in liver and lung. Moreover, we show that CD8+ T cells but not NKT cells were required for hepatocyte injury: elevated concentrations of serum alanine aminotransferase and infection-induced subcapsular necrotic liver lesions surrounded by macrophages were found in C57Bl/6 and CD1d-deficient mice, but not in beta 2-microglobulin knockout mice. In the lungs, peribronchial macrophage infiltrations also depended on CD8+ T cells. In summary, our results demonstrate that CD8+ T cells restrict growth of O. tsutsugamushi during acute and persistent infection, and are required to protect from lethal infections in BALB/c and C57BL/6 mice. However, they also elicit specific pathologic tissue lesions in liver and lung. PMID:27606708

  8. A Low Peripheral Blood CD4/CD8 Ratio Is Associated with Pulmonary Emphysema in HIV

    PubMed Central

    Attia, Engi F.; Akgün, Kathleen M.; Soo Hoo, Guy W.; Freiberg, Matthew S.; Butt, Adeel A.; Wongtrakool, Cherry; Goetz, Matthew Bidwell; Brown, Sheldon T.; Graber, Christopher J.; Huang, Laurence; Crothers, Kristina

    2017-01-01

    Objectives The prevalence of emphysema is higher among HIV-infected (HIV+) individuals compared to HIV-uninfected persons. While greater tobacco use contributes, HIV-related effects on immunity likely confer additional risk. Low peripheral blood CD4+ to CD8+ T-lymphocyte (CD4/CD8) ratio may reflect chronic inflammation in HIV and may be a marker of chronic lung disease in this population. Therefore, we sought to determine whether the CD4/CD8 ratio was associated with chronic obstructive pulmonary disease (COPD), particularly the emphysema subtype, in a cohort of HIV+ subjects. Methods We performed a cross-sectional analysis of 190 HIV+ subjects enrolled in the Examinations of HIV Associated Lung Emphysema (EXHALE) study. Subjects underwent baseline laboratory assessments, pulmonary function testing and chest computed tomography (CT) analyzed for emphysema severity and distribution. We determined the association between CD4/CD8 ratio and emphysema, and the association between CD4/CD8 ratio and pulmonary function markers of COPD. Results Mild or greater emphysema (>10% lung involvement) was present in 31% of subjects. Low CD4/CD8 ratio was associated with >10% emphysema in multivariable models, adjusting for risk factors including smoking, current and nadir CD4 count and HIV RNA level. Those with CD4/CD8 ratio <0.4 had 6.3 (1.1–39) times the odds of >10% emphysema compared to those with a ratio >1.0 in fully adjusted models. A low CD4/CD8 ratio was also associated with reduced diffusion capacity (DLCO). Conclusions A low CD4/CD8 ratio was associated with emphysema and low DLCO in HIV+ subjects, independent of other risk factors and clinical markers of HIV. The CD4/CD8 ratio may be a useful, clinically available, marker for risk of emphysema in HIV+ subjects in the antiretroviral therapy (ART) era. PMID:28122034

  9. Isolation of human CD4/CD8 double-positive, graft-versus-host disease-protective, minor histocompatibility antigen-specific regulatory T cells and of a novel HLA-DR7-restricted HY-specific CD4 clone.

    PubMed

    Eljaafari, Assia; Yuruker, Ozel; Ferrand, Christophe; Farre, Annie; Addey, Caroline; Tartelin, Marie-Laure; Thomas, Xavier; Tiberghien, Pierre; Simpson, Elizabeth; Rigal, Dominique; Scott, Diane

    2013-01-01

    Minor histocompatibility (H) Ags are classically described as self-peptides derived from intracellular proteins that are expressed at the cell surface by MHC class I and class II molecules and that induce T cell alloresponses. We have isolated three different T cell populations from a skin biopsy of a patient suffering from acute graft-versus-host disease following sex-mismatched HLA-identical bone marrow transplantation. The first population was: 1) CD4(+)/CD8(+) double-positive; 2) specific for an HLA class I-restricted autosomal Ag; 3) expressed a Tr1 profile with high levels of IL-10, but low IL-2 and IFN-γ; and 4) exerted regulatory function in the presence of recipient APCs. The second was CD8 positive, specific for an HLA class I-restricted autosomally encoded minor H Ag, but was only weakly cytotoxic. The third was CD4 single positive, specific for an HLA-DR7-restricted HY epitope and exerted both proliferative and cytotoxic functions. Identification of the peptide recognized by these latter cells revealed a new human HY epitope, TGKIINFIKFDTGNL, encoded by RPS4Y and restricted by HLA-DR7. In this paper, we show human CD4/CD8 double-positive, acute graft-versus-host disease-protective, minor H Ag-specific regulatory T cells and identify a novel HLA-DR7/ HY T cell epitope, encoded by RPS4Y, a potential new therapeutic target.

  10. Generation of functional, antigen-specific CD8+ human T cells from cord blood stem cells using exogenous Notch and tetramer-TCR signaling.

    PubMed

    Fernandez, Irina; Ooi, Tracy P; Roy, Krishnendu

    2014-01-01

    In vitro differentiation of mouse and human stem cells into early T cells has been successfully demonstrated using artificial Notch signaling systems. However, generation of mature, antigen-specific, functional T cells, directly from human stem cells has remained elusive, except when using stromal coculture of stem cells retrovirally transfected with antigen-specific T cell receptors (TCRs). Here we show that human umbilical cord blood (UCB)-derived CD34+CD38-/low hematopoietic stem cells can be successfully differentiated into functional, antigen-specific cytotoxic CD8+ T cells without direct stromal coculture or retroviral TCR transfection. Surface-immobilized Notch ligands (DLL1) and stromal cell conditioned medium successfully induced the development of CD1a+CD7+ and CD4+CD8+ early T cells. These cells, upon continued culture with cytomegalovirus (CMV) or influenza-A virus M1 (GIL) epitope-loaded human leukocyte antigen (HLA)-A*0201 tetramers, resulted in the generation of a polyclonal population of CMV-specific or GIL-specific CD8+ T cells, respectively. Upon further activation with antigen-loaded target cells, these antigen-specific, stem cell-derived T cells exhibited cytolytic functionality, specifically CD107a surface mobilization, interferon gamma (IFNg) production, and Granzyme B secretion. Such scalable, in vitro generation of functional, antigen-specific T cells from human stem cells could eventually provide a readily available cell source for adoptive transfer immunotherapies and also allow better understanding of human T cell development.

  11. Angiotensin II type-1 receptor (AT1R) regulates expansion, differentiation, and functional capacity of antigen-specific CD8+ T cells

    PubMed Central

    Silva-Filho, João Luiz; Caruso-Neves, Celso; Pinheiro, Ana Acacia Sá

    2016-01-01

    Angiotensin II (Ang II) and its receptor AT1 (AT1R), an important effector axis of renin-angiotensin system (RAS), have been demonstrated to regulate T-cell responses. However, these studies characterized Ang II and AT1R effects using pharmacological tools, which do not target only Ang II/AT1R axis. The specific role of AT1R expressed by antigen-specific CD8+ T cells is unknown. Then we immunized transgenic mice expressing a T-cell receptor specific for SIINFEKL epitope (OT-I mice) with sporozoites of the rodent malaria parasite Plasmodium berghei expressing the cytotoxic epitope SIINFEKL. Early priming events after immunization were not affected but the expansion and contraction of AT1R-deficient (AT1R−/−) OT-I cells was decreased. Moreover, they seemed more activated, express higher levels of CTLA-4, PD-1, LAG-3, and have decreased functional capacity during the effector phase. Memory AT1R−/− OT-I cells exhibited higher IL-7Rα expression, activation, and exhaustion phenotypes but less cytotoxic capacity. Importantly, AT1R−/− OT-I cells show better control of blood parasitemia burden and ameliorate mice survival during lethal disease induced by blood-stage malaria. Our study reveals that AT1R in antigen-specific CD8+ T cells regulates expansion, differentiation, and function during effector and memory phases of the response against Plasmodium, which could apply to different infectious agents. PMID:27782175

  12. Vaccination of rhesus monkeys with synthetic peptide in a fusogenic proteoliposome elicits simian immunodeficiency virus-specific CD8+ cytotoxic T lymphocytes

    PubMed Central

    1992-01-01

    An effective vaccine against the human immunodeficiency virus should be capable of eliciting both an antibody and a cytotoxic T lymphocyte (CTL) response. However, when viral proteins and peptides are formulated with traditional immunological adjuvants and inoculated via a route acceptable for use in humans, they have not been successful at eliciting virus-specific, major histocompatibility complex (MHC) class I-restricted CTL. We have designed a novel viral subunit vaccine by encapsulating a previously defined synthetic peptide CTL epitope of the simian immunodeficiency virus (SIV) gag protein within a proteoliposome capable of attaching to and fusing with plasma membranes. Upon fusing, the encapsulated contents of this proteoliposome can enter the MHC class I processing pathway through the cytoplasm. In this report, we show that after a single intramuscular vaccination, rhesus monkeys develop a CD8+ cell-mediated, MHC class I-restricted CTL response that recognizes the synthetic peptide immunogen. The induced CTL also demonstrate antiviral immunity by recognizing SIV gag protein endogenously processed by target cells infected with SIV/vaccinia recombinant virus. These results demonstrate that virus-specific, MHC class I-restricted, CD8+ CTL can be elicited by a safe, nonreplicating viral subunit vaccine in a primate model for acquired immune deficiency syndrome. Moreover, the proteoliposome vaccine formation described can include multiple synthetic peptide epitopes, and, thus, offers a simple means of generating antiviral cell-mediated immunity in a genetically heterogeneous population. PMID:1460429

  13. CD4+ T cells are not required for the induction of dengue virus-specific CD8+ T cell or antibody responses but contribute to protection after vaccination.

    PubMed

    Yauch, Lauren E; Prestwood, Tyler R; May, Monica M; Morar, Malika M; Zellweger, Raphaël M; Peters, Bjoern; Sette, Alessandro; Shresta, Sujan

    2010-11-01

    The contribution of T cells to the host response to dengue virus (DENV) infection is not well understood. We previously demonstrated a protective role for CD8(+) T cells during primary DENV infection using a mouse-passaged DENV strain and IFN-α/βR(-/-) C57BL/6 mice, which are susceptible to DENV infection. In this study, we examine the role of CD4(+) T cells during primary DENV infection. Four I-A(b)-restricted epitopes derived from three of the nonstructural DENV proteins were identified. CD4(+) T cells expanded and were activated after DENV infection, with peak activation occurring on day 7. The DENV-specific CD4(+) T cells expressed intracellular IFN-γ, TNF, IL-2, and CD40L, and killed peptide-pulsed target cells in vivo. Surprisingly, depletion of CD4(+) T cells before DENV infection had no effect on viral loads. Consistent with this observation, CD4(+) T cell depletion did not affect the DENV-specific IgG or IgM Ab titers or their neutralizing activity, or the DENV-specific CD8(+) T cell response. However, immunization with the CD4(+) T cell epitopes before infection resulted in significantly lower viral loads. Thus, we conclude that whereas CD4(+) T cells are not required for controlling primary DENV infection, their induction by immunization can contribute to viral clearance. These findings suggest inducing anti-DENV CD4(+) T cell responses by vaccination may be beneficial.

  14. Trogocytosis is a gateway to characterize functional diversity in melanoma-specific CD8+ T cell clones.

    PubMed

    Uzana, Ronny; Eisenberg, Galit; Sagi, Yael; Frankenburg, Shoshana; Merims, Sharon; Amariglio, Ninette; Yefenof, Eitan; Peretz, Tamar; Machlenkin, Arthur; Lotem, Michal

    2012-01-15

    Trogocytosis, the transfer of membrane patches from target to immune effector cells, is a signature of tumor-T cell interaction. In this study, we used the trogocytosis phenomenon to study functional diversity within tumor-specific T cell clones with identical TCR specificity. MART-1(26-35)-specific CD8 T cell clones, which differed in their trogocytosis capacity (low [2D11], intermediate [2G1], high [2E2]), were generated from melanoma patients. Functional evaluation of the clones showed that the percentage of trogocytosis-capable T cells closely paralleled each clone's IFN-γ and TNF-α production, lysosome degranulation, and lysis of peptide-pulsed targets and unmodified melanoma. The highly cytotoxic 2E2 clone displayed the highest TCR peptide binding affinity, whereas the low-activity 2D11 clone showed TCR binding to peptide-MHC in a CD8-dependent manner. TCR analysis revealed Vβ16 for clones 2E2 and 2G1 and Vβ14 for 2D11. When peptide-affinity differences were bypassed by nonspecific TCR stimulation, clones 2E2 and 2D11 still manifested distinctive signaling patterns. The high-activity 2E2 clone displayed prolonged phosphorylation of ribosomal protein S6, an integrator of MAPK and AKT activation, whereas the low-activity 2D11 clone generated shorter and weaker phosphorylation. Screening the two clones with identical TCR Vβ by immunoreceptor array showed higher phosphorylation of NK, T, and B cell Ag (NTB-A), a SLAM family homophilic receptor, in clone 2E2 compared with 2G1. Specific blocking of NTB-A on APCs markedly reduced cytokine production by CD8 lymphocytes, pointing to a possible contribution of NTB-A costimulation to T cell functional diversity. This finding identifies NTB-A as a potential target for improving anti-cancer immunotherapy.

  15. Immunogenicity of adenovirus-derived porcine parvovirus-like particles displaying B and T cell epitopes of foot-and-mouth disease.

    PubMed

    Pan, Qunxing; Wang, Hui; Ouyang, Wei; Wang, Xiaoli; Bi, Zhenwei; Xia, Xingxia; Wang, Yongshan; He, Kongwang

    2016-01-20

    Virus-like particles (VLPs) vaccines combine many of the advantages of whole-virus vaccines and recombinant subunit vaccines, integrating key features that underlay their immunogenicity, safety and protective potential. We have hypothesized here the effective insertion of the VP1 epitopes (three amino acid residues 21-40, 141-160 and 200-213 in VP1, designated VPe) of foot-and-mouth disease (FMDV) within the external loops of PPV VP2 could be carried out without altering assembly based on structural and antigenic data. To investigate the possibility, development of two recombinant adenovirus rAd-PPV:VP2-FMDV:VPe a or rAd-PPV:VP2-FMDV:VPe b were expressed in HEK-293 cells. Out of the two insertion strategies tested, one of them tolerated an insert of 57 amino acids in one of the four external loops without disrupting the VLPs assembly. Mice were inoculated with the two recombinant adenoviruses, and an immunogenicity study showed that the highest levels of FMDV-specific humoral responses and T cell proliferation could be induced by rAd-PPV:VP2-FMDV:VPe b expressing hybrid PPV:VLPs (FMDV) in the absence of an adjuvant. Then, the protective efficacy of inoculating swine with rAd-PPV:VP2-FMDV:VPe b was tested. All pigs inoculated with rAd-PPV:VP2-FMDV:VPe b were protected from viral challenge, meanwhile the neutralizing antibody titers were significantly higher than those in the group inoculated with swine FMD type O synthetic peptide vaccine. Our results clearly demonstrate the potential usefulness of adenovirus-derived PPV VLPs as a vaccine strategy in prevention of FMDV.

  16. Transduction of SIV-Specific TCR Genes into Rhesus Macaque CD8+ T Cells Conveys the Ability to Suppress SIV Replication

    PubMed Central

    Barsov, Eugene V.; Trivett, Matthew T.; Minang, Jacob T.; Sun, Haosi; Ohlen, Claes; Ott, David E.

    2011-01-01

    Background The SIV/rhesus macaque model for HIV/AIDS is a powerful system for examining the contribution of T cells in the control of AIDS viruses. To better our understanding of CD8+ T-cell control of SIV replication in CD4+ T cells, we asked whether TCRs isolated from rhesus macaque CD8+ T-cell clones that exhibited varying abilities to suppress SIV replication could convey their suppressive properties to CD8+ T cells obtained from an uninfected/unvaccinated animal. Principal Findings We transferred SIV-specific TCR genes isolated from rhesus macaque CD8+ T-cell clones with varying abilities to suppress SIV replication in vitro into CD8+ T cells obtained from an uninfected animal by retroviral transduction. After sorting and expansion, transduced CD8+ T-cell lines were obtained that specifically bound their cognate SIV tetramer. These cell lines displayed appropriate effector function and specificity, expressing intracellular IFNγ upon peptide stimulation. Importantly, the SIV suppression properties of the transduced cell lines mirrored those of the original TCR donor clones: cell lines expressing TCRs transferred from highly suppressive clones effectively reduced wild-type SIV replication, while expression of a non-suppressing TCR failed to reduce the spread of virus. However, all TCRs were able to suppress the replication of an SIV mutant that did not downregulate MHC-I, recapitulating the properties of their donor clones. Conclusions Our results show that antigen-specific SIV suppression can be transferred between allogenic T cells simply by TCR gene transfer. This advance provides a platform for examining the contributions of TCRs versus the intrinsic effector characteristics of T-cell clones in virus suppression. Additionally, this approach can be applied to develop non-human primate models to evaluate adoptive T-cell transfer therapy for AIDS and other diseases. PMID:21886812

  17. Apoptosis of tumor infiltrating effector TIM-3+CD8+ T cells in colon cancer.

    PubMed

    Kang, Chiao-Wen; Dutta, Avijit; Chang, Li-Yuan; Mahalingam, Jayashri; Lin, Yung-Chang; Chiang, Jy-Ming; Hsu, Chen-Yu; Huang, Ching-Tai; Su, Wan-Ting; Chu, Yu-Yi; Lin, Chun-Yen

    2015-10-23

    TIM-3 functions to enforce CD8+ T cell exhaustion, a dysfunctional state associated with the tolerization of tumor microenvironment. Here we report apoptosis of IFN-γ competent TIM-3+ population of tumor-infiltrating CD8+ T cells in colon cancer. In humans suffering from colorectal cancer, TIM-3+ population is higher in cancer tissue-resident relative to peripheral blood CD8+ T cells. Both the TIM-3+ and TIM-3- cancer tissue-resident CD8+ T cells secrete IFN-γ of comparable levels, although apoptotic cells are more in TIM-3+ compared to TIM-3- population. In mouse CT26 colon tumor model, majority of tumor-infiltrating CD8+ T cells express TIM-3 and execute cytolysis function with higher effector cytokine secretion and apoptosis in TIM-3+ compared to TIM-3- population. The tumor cells secrete galectin-9, which increases apoptosis of tumor-infiltrating CD8+ T cells. Galectin-9/TIM-3 signaling blockade with anti-TIM-3 antibody reduces the apoptosis and in addition, inhibits tumor growth in mice. The blockade increases therapeutic efficacy of cyclophosphamide to treat tumor in mice as well. These results reveal a previously unexplored role of TIM-3 on tumor-infiltrating CD8+ T cells in vivo.

  18. Antigen Exposure History Defines CD8 T Cell Dynamics and Protection during Localized Pulmonary Infections

    PubMed Central

    Van Braeckel-Budimir, Natalija; Martin, Matthew D.; Hartwig, Stacey M.; Legge, Kevin L.; Badovinac, Vladimir P.; Harty, John T.

    2017-01-01

    Unlike systemic infections, little is known about the role of repeated localized infections on (re)shaping pathogen-specific memory CD8 T cell responses. Here, we used primary (1°) and secondary (2°) intranasal influenza virus infections of mice as a model to study intrinsic memory CD8 T cell properties. We show that secondary antigen exposure, relative to a single infection, generates memory CD8 T cell responses of superior magnitude in multiple tissue compartments including blood, spleen, draining lymph nodes, and lung. Unexpectedly, regardless of the significantly higher number of 2° memory CD8 T cells, similar degree of protection against pulmonary challenge was observed in both groups of mice containing 1° or 2° memory CD8 T cells. Mechanistically, using pertussis toxin-induced migration block, we showed that superior antigen-driven proliferation and ability to relocate to the site of infection allowed 1° memory CD8 T cells to accumulate in the infected lung during the first few days after challenge, compensating for the initially lower cell numbers. Taken together, the history of antigen exposures to localized pulmonary infections, through altering basic cell biology, dictates dynamic properties of protective memory CD8 T cell responses. This knowledge has important implications for a design of novel and an improvement of existing vaccines and immunization strategies. PMID:28191007

  19. CD8+ tumor-infiltrating lymphocytes predict favorable prognosis in malignant pleural mesothelioma after resection.

    PubMed

    Yamada, Noriyuki; Oizumi, Satoshi; Kikuchi, Eiki; Shinagawa, Naofumi; Konishi-Sakakibara, Jun; Ishimine, Atsushi; Aoe, Keisuke; Gemba, Kenichi; Kishimoto, Takumi; Torigoe, Toshihiko; Nishimura, Masaharu

    2010-10-01

    Defects in human leukocyte antigen (HLA) class I expression may allow tumor cells to escape immune recognition. T cell infiltration is associated with a good prognosis in many cancers. However, the role of HLA class I expression and tumor-infiltrating lymphocytes (TILs) in malignant pleural mesothelioma (MPM) has not been fully analyzed. In the present study, we investigated the immune profiles and conducted outcome analyses of MPM patients. HLA class I expression and TILs (CD4(+), CD8(+), and NK cells) were detected by immunohistochemistry in a series of 44 MPM cases. To detect HLA class I expression, specimens were stained with the anti-pan HLA class I monoclonal antibody EMR8-5. The expression of HLA class I was positive in all patients. There was no case that showed negative HLA class I expression. The density of CD4(+) and CD8(+) TILs were strongly correlated (R = 0.76, p < 0.001). A high density of CD8(+) TILs was a significantly better prognostic factor for the survival of patients with extrapleural pneumonectomy (p < 0.05). Multivariate analysis revealed that a high density of CD8(+) TILs is an independent prognostic factor for patients who underwent extrapleural pneumonectomy. The presence of intratumoral CD8(+) T cells was correlated with an improved clinical outcome, raising the possibility that CD8(+) T cells might play a pivotal role in the antitumor immune response against MPMs. Thus, the stimulation of CD8(+) lymphocytes might be an efficacious immunotherapy for MPM patients.

  20. The possible role of virus-specific CD8(+) memory T cells in decidual tissue.

    PubMed

    van Egmond, A; van der Keur, C; Swings, G M J S; Scherjon, S A; Claas, F H J

    2016-02-01

    The most abundant lymphocyte present in decidual tissue is the CD8(+) T cell. It has been shown that most decidual CD8(+) T cells have an effector-memory phenotype, but expressed reduced levels of perforin and granzyme B compared with the peripheral CD8(+) effector-memory T cells. The specificity of these CD8(+) memory T cells has yet to be determined. One hypothesis is that the decidual memory T cells are virus-specific T cells that should protect the fetus against incoming pathogens. As virus-specific CD8(+) memory T cells can cross-react with human leukocyte alloantigens, an alternative, but not mutually exclusive, hypothesis is that these CD8(+) T cells are fetus-specific. Using virus-specific tetramers, we found increased percentages of virus-specific CD8(+) T cells in decidual tissue compared with peripheral blood after uncomplicated pregnancy. So far, no evidence has been obtained for a cross-reactive response of these virus-specific T cells to fetal human leukocyte antigens. These results suggest that the virus-specific memory T cells accumulate in the placenta to protect the fetus from a harmful infection.

  1. Type I interferons regulate eomesodermin expression and the development of unconventional memory CD8(+) T cells.

    PubMed

    Martinet, Valérie; Tonon, Sandrine; Torres, David; Azouz, Abdulkader; Nguyen, Muriel; Kohler, Arnaud; Flamand, Véronique; Mao, Chai-An; Klein, William H; Leo, Oberdan; Goriely, Stanislas

    2015-05-08

    CD8(+) T-cell memory phenotype and function are acquired after antigen-driven activation. Memory-like cells may also arise in absence of antigenic exposure in the thymus or in the periphery. Eomesodermin (Eomes) is a key transcription factor for the development of these unconventional memory cells. Herein, we show that type I interferon signalling in CD8(+) T cells directly activates Eomes gene expression. Consistent with this observation, the phenotype, function and age-dependent expansion of 'virtual memory' CD8(+) T cells are strongly affected in absence of type I interferon signalling. In addition, type I interferons induce a sustained expansion of 'virtual memory' CD8(+) T cells in an Eomes-dependent fashion. We further show that the development of 'innate thymic' CD8(+) T cells is dependent on the same pathway. In conclusion, we demonstrate that type I interferon signalling in CD8(+) T cells drives Eomes expression and thereby regulates the function and homeostasis of memory-like CD8(+) T cells.

  2. Antiviral CD8-mediated responses in chronic HCV carriers with HBV superinfection.

    PubMed

    Boni, Carolina; Amadei, Barbara; Urbani, Simona; Fisicaro, Paola; Zerbini, Alessandro; Mori, Cristina; Missale, Gabriele; Bertoni, Roberto; Azzurri, Annalisa; Del Prete, Gianfranco; Ferrari, Carlo

    2004-08-01

    Hepatitis B virus (HBV) superinfection in chronic hepatitis C represents a natural model to investigate whether or not hepatitis C virus (HCV) can influence priming and maturation of antiviral T cells; whether or not HBV superinfection, which is known to determine control of HCV replication, can restore HCV-specific T cell responsiveness; and whether or not cytokines stimulated by HBV infection can contribute to HCV control. To address these issues, the function of CD8 cells specific for HBV and HCV was studied longitudinally in two chronic HCV patients superinfected with HBV. Patients with acute hepatitis B were also examined. Frequency and function of HBV tetramer+ CD8 cells were comparable in patients acutely infected with HBV with or without chronic HCV infection. HBV-specific CD8 cell function was efficiently expressed irrespective of serum HCV-RNA levels. Moreover, fluctuations of HCV viremia at the time of HBV superinfection were not associated with evident changes of CD8 responsiveness to HCV. Finally, no correlation was found between serum levels of interferon alpha, interleukin (IL)-12, IL-10, or IL-18 and control of HCV replication. In conclusion, HCV did not affect the induction of primary and memory HBV-specific CD8 responses. HCV-specific CD8 responses were undetectable when HCV-RNA was negative, showing that inhibition of HCV replication in the setting of a HBV superinfection was not sufficient to induce a restoration of CD8 reactivity against HCV.

  3. Antigen persistence is required for dendritic cell licensing and CD8+ T cell cross-priming.

    PubMed

    Jusforgues-Saklani, Hélène; Uhl, Martin; Blachère, Nathalie; Lemaître, Fabrice; Lantz, Olivier; Bousso, Philippe; Braun, Deborah; Moon, James J; Albert, Matthew L

    2008-09-01

    It has been demonstrated that CD4(+) T cells require Ag persistence to achieve effective priming, whereas CD8(+) T cells are on "autopilot" after only a brief exposure. This finding presents a disturbing conundrum as it does not account for situations in which CD8(+) T cells require CD4(+) T cell help. We used a physiologic in vivo model to study the requirement of Ag persistence for the cross-priming of minor histocompatibility Ag-specific CD8(+) T cells. We report inefficient cross-priming in situations in which male cells are rapidly cleared. Strikingly, the failure to achieve robust CD8(+) T cell activation is not due to a problem with cross-presentation. In fact, by providing "extra help" in the form of dendritic cells (DCs) loaded with MHC class II peptide, it was possible to achieve robust activation of CD8(+) T cells. Our data suggest that the "licensing" of cross-presenting DCs does not occur during their initial encounter with CD4(+) T cells, thus accounting for the requirement for Ag persistence and suggesting that DCs make multiple interactions with CD8(+) T cells during the priming phase. These findings imply that long-lived Ag is critical for efficient vaccination protocols in which the CD8(+) T cell response is helper-dependent.

  4. Alpha tumor necrosis factor contributes to CD8{sup +} T cell survival in the transition phase

    SciTech Connect

    Shi, Meiqing; Ye, Zhenmin; Umeshappa, Keshav Sokke; Moyana, Terence; Xiang, Jim . E-mail: jxiang@scf.sk.ca

    2007-08-31

    Cytokine and costimulation signals determine CD8{sup +} T cell responses in proliferation phase. In this study, we assessed the potential effect of cytokines and costimulations to CD8{sup +} T cell survival in transition phase by transferring in vitro ovalbumin (OVA)-pulsed dendritic cell-activated CD8{sup +} T cells derived from OVA-specific T cell receptor transgenic OT I mice into wild-type C57BL/6 mice or mice with designated gene knockout. We found that deficiency of IL-10, IL-12, IFN-{gamma}, CD28, CD40, CD80, CD40L, and 41BBL in recipients did not affect CD8{sup +} T cell survival after adoptive transfer. In contrast, TNF-{alpha} deficiency in both recipients and donor CD8{sup +} effector T cells significantly reduced CD8{sup +} T cell survival. Therefore, our data demonstrate that the host- and T cell-derived TNF-{alpha} signaling contributes to CD8{sup +} effector T cell survival and their transition to memory T cells in the transition phase, and may be useful information when designing vaccination.

  5. Relapsing-remitting CNS autoimmunity mediated by GFAP-specific CD8 T cells

    PubMed Central

    Sasaki, Katsuhiro; Bean, Angela; Shah, Shivanee; Schutten, Elizabeth; Huseby, Priya G.; Peters, Bjorn; Shen, Zu T.; Vanguri, Vijay; Liggitt, Denny; Huseby, Eric S.

    2014-01-01

    Multiple Sclerosis (MS) is an inflammatory disease of the CNS that causes the demyelination of nerve cells and destroys oligodendrocytes, neurons and axons. Historically, MS has been thought to be a CD4 T cell-mediated autoimmune disease of CNS white matter. However, recent studies have identified CD8 T cell infiltrates and gray matter lesions in MS patients. These findings suggest that CD8 T cells, and CNS antigens other than myelin proteins may be involved during the MS disease process. Here we show that CD8 T cells reactive to glial fibrillary acidic protein (GFAP), a protein expressed in astrocytes, can avoid tolerance mechanisms, and depending upon the T cell triggering event, drive unique aspects of inflammatory CNS autoimmunity. In GFAP-specific CD8 T cell receptor transgenic (BG1) mice, tissue resident memory-like CD8 T cells spontaneously infiltrate the gray matter and white matter of the CNS, resulting in a relapsing-remitting CNS autoimmunity. The frequency, severity and remissions from spontaneous disease are controlled by the presence of polyclonal B cells. In contrast, a viral trigger induces GFAP-specific CD8 T effector cells to exclusively target the meninges and vascular/perivascular space of the gray and white matter of the brain, causing a rapid, acute CNS disease. These findings demonstrate that the type of CD8 T cell-triggering event can determine the presentation of distinct CNS autoimmune disease pathologies. PMID:24591371

  6. In Vivo Magnetic Resonance Imaging of CD8+ T Lymphocytes Recruiting to Glioblastoma in Mice.

    PubMed

    Li, Anning; Wu, Yue; Tang, Feng; Li, Wei; Feng, Xiaoyuan; Yao, Zhenwei

    2016-11-01

    Noninvasive in vivo tracking of adopted immune cells would help improve immunotherapy on glioblastoma. In this study, the authors tried to track adoptive CD8+ T lymphocytes in an in situ GL261 glioblastoma mouse model with magnetic resonance imaging (MRI). CD8+ T lymphocytes from spleen of preimmunized GL261 glioblastoma mice were labeled with superparamagnetic iron oxide, with polylysine as transfection agent. From Prussian blue staining, the labeling efficiency was 0.77% ± 0.06%, without altering cell viability and function. From anti-CD8, and anti-dextran staining, superparamagnetic iron oxide could be seen in the cytoplasm. In vitro imaging of agar gel mixtures with different concentrations of labeled CD8+ T lymphocytes was done with a 3.0T MR T2*WI sequence. Higher cell concentrations showed lower signal values. Twenty-four hours after tail vein injection of labeled and unlabeled CD8+ T lymphocytes, imaging of GL261 mice brain showed black spots at the periphery of the tumor in the labeled group only. Brain tumor pathology further verified infiltration of labeled CD8+ T lymphocytes in the tumor. Thus, preimmunized CD8+ T lymphocytes could be efficiently labeled with superparamagnetic iron oxide and tracked both in vitro and in vivo with 3.0T MRI.

  7. Potentiating the antitumour response of CD8+ T cells by modulating cholesterol metabolism

    PubMed Central

    Yang, Wei; Bai, Yibing; Xiong, Ying; Zhang, Jin; Chen, Shuokai; Zheng, Xiaojun; Meng, Xiangbo; Li, Lunyi; Wang, Jing; Xu, Chenguang; Yan, Chengsong; Wang, Lijuan; Chang, Catharine C. Y.; Chang, Ta-Yuan; Zhang, Ti; Zhou, Penghui; Song, Bao-Liang; Liu, Wanli; Sun, Shao-cong; Liu, Xiaolong; Li, Bo-liang; Xu, Chenqi

    2016-01-01

    CD8+ T cells have a central role in antitumour immunity, but their activity is suppressed in the tumour microenvironment1–4. Reactivating the cytotoxicity of CD8+ T cells is of great clinical interest in cancer immunotherapy. Here we report a new mechanism by which the antitumour response of mouse CD8+ T cells can be potentiated by modulating cholesterol metabolism. Inhibiting cholesterol esterification in T cells by genetic ablation or pharmacological inhibition of ACAT1, a key cholesterol esterification enzyme5, led to potentiated effector function and enhanced proliferation of CD8+ but not CD4+ T cells. This is due to the increase in the plasma membrane cholesterol level of CD8+ T cells, which causes enhanced T-cell receptor clustering and signalling as well as more efficient formation of the immunological synapse. ACAT1-deficient CD8+ T cells were better than wild-type CD8+ T cells at controlling melanoma growth and metastasis in mice. We used the ACAT inhibitor avasimibe, which was previously tested in clinical trials for treating atherosclerosis and showed a good human safety profile6,7, to treat melanoma in mice and observed a good antitumour effect. A combined therapy of avasimibe plus an anti-PD-1 antibody showed better efficacy than monotherapies in controlling tumour progression. ACAT1, an established target for atherosclerosis, is therefore also a potential target for cancer immunotherapy. PMID:26982734

  8. Targeting the genital tract mucosa with a lipopeptide/recombinant adenovirus prime/boost vaccine induces potent and long-lasting CD8+ T cell immunity against herpes: importance of MyD88.

    PubMed

    Zhang, Xiuli; Dervillez, Xavier; Chentoufi, Aziz Alami; Badakhshan, Tina; Bettahi, Ilham; Benmohamed, Lbachir

    2012-11-01

    Targeting of the mucosal immune system of the genital tract with subunit vaccines has failed to induce potent and durable local CD8(+) T cell immunity, which is crucial for protection against many sexually transmitted viral pathogens, including HSV type 2 (HSV-2), which causes genital herpes. In this study, we aimed to investigate the potential of a novel lipopeptide/adenovirus type 5 (Lipo/rAdv5) prime/boost mucosal vaccine for induction of CD8(+) T cell immunity to protect the female genital tract from herpes. The lipopeptide vaccine and the rAdv5 vaccine express the immunodominant HSV-2 CD8(+) T cell epitope (gB(498-505)), and both were delivered intravaginally in the progesterone-induced B6 mouse model of genital herpes. Compared with mice immunized with the homologous lipopeptide/lipopeptide (Lipo/Lipo) vaccine, the Lipo/rAdv5 prime/boost immunized mice 1) developed potent and sustained HSV-specific CD8(+) T cells, detected in both the genital tract draining nodes and in the vaginal mucosa; 2) had significantly lower virus titers; 3) had decreased overt signs of genital herpes disease; and 4) did not succumb to lethal infection (p < 0.005) after intravaginal HSV-2 challenge. Polyfunctional CD8(+) T cells, producing IFN-γ, TNF-α, and IL-2 and exhibiting cytotoxic activity, were associated with protection (p < 0.005). The protective CD8(+) T cell response was significantly compromised in the absence of the adapter MyD88 (p = 0.0001). Taken together, these findings indicate that targeting of the vaginal mucosa with a Lipo/rAdv5 prime/boost vaccine elicits a potent, MyD88-dependent, and long-lasting mucosal CD8(+) T cell protective immunity against sexually transmitted herpes infection and disease.

  9. In Situ Staining and Laser Capture Microdissection of Lymph Node Residing SIV Gag-Specific CD8+ T cells—A Tool to Interrogate a Functional Immune Response Ex Vivo

    PubMed Central

    Tjernlund, Annelie; Burgener, Adam; Lindvall, Jessica M.; Peng, Tao; Zhu, Jia; Öhrmalm, Lars; Picker, Louis J.; Broliden, Kristina; McElrath, M. Juliana; Corey, Lawrence

    2016-01-01

    While a plethora of data describes the essential role of systemic CD8+ T cells in the control of SIV replication little is known about the local in situ CD8+ T cell immune responses against SIV at the intact tissue level, due to technical limitations. In situ staining, using GagCM9 Qdot 655 multimers, were here combined with laser capture microdissection to detect and collect SIV Gag CM9 specific CD8+ T cells in lymph node tissue from SIV infected rhesus macaques. CD8+ T cells from SIV infected and uninfected rhesus macaques were also collected and compared to the SIV GagCM9 specific CD8+ T cells. Illumina bead array and transcriptional analyses were used to assess the transcriptional profiles and the three different CD8+ T cell populations displayed unique transcriptional patterns. This pilot study demonstrates that rapid and specific immunostaining combined with laser captu