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Sample records for t-cell proliferative responses

  1. Cytotoxic and proliferative T cell responses in HIV-1-infected Macaca nemestrina.

    OpenAIRE

    Kent, S J; Corey, L; Agy, M B; Morton, W R; McElrath, M J; Greenberg, P D

    1995-01-01

    Macaca nemestrina has been described as an animal model for acute HIV-1 infection. This animal, unlike most infected humans, appears to contain HIV-1 replication. Therefore analysis of HIV-1-specific proliferative and cytotoxic T lymphocyte (CTL) responses following HIV-1 challenge of M. nemestrina may provide information into the role of such responses in both the control of acute HIV infection and protective immunity. Although CD4+ T cell responses to HIV-1 are generally difficult to detect...

  2. Long-term nonprogression and broad HIV-1-specific proliferative T-cell responses

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    Nesrina eImami

    2013-03-01

    Full Text Available Complex mechanisms underlying the maintenance of fully functional, proliferative, HIV-1-specific T-cell responses involve processes from early T-cell development through to the final stages of T-cell differentiation and antigen recognition. Virus-specific proliferative CD4 and CD8 T-cell responses, important for the control of infection, are observed in some HIV-1+ patients during early stages of disease, and are maintained in long-term nonprogressing subjects. In the vast majority of HIV-1+ patients, full immune functionality is lost when proliferative HIV-1-specific T-cell responses undergo a variable progressive decline throughout the course of chronic infection. This appears irreparable despite administration of potent combination antiretroviral therapy, which to date is non-curative, necessitating life-long administration and the development of effective, novel, therapeutic interventions. While a sterilising cure, involving clearance of virus from the host, remains a primary aim, a functional cure may be a more feasible goal with considerable impact on worldwide HIV-1 infection. Such an approach would enable long-term co-existence of host and virus in the absence of toxic and costly drugs. Effective immune homeostasis coupled with a balanced response appropriately targeting conserved viral antigens, in a manner that avoids hyperactivation and exhaustion, may prove to be the strongest correlate of durable viral control. This review describes novel concepts underlying full immune functionality in the context of HIV-1 infection, which may be utilised in future strategies designed to improve upon existing therapy. The aim will be to induce long-term nonprogressor or elite controller status in every infected host, through immune-mediated control of viraemia and reduction of viral reservoirs, leading to lower HIV-1 transmission rates.

  3. Human CD6 Down-Modulation following T-Cell Activation Compromises Lymphocyte Survival and Proliferative Responses

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    Esther Carrasco

    2017-06-01

    Full Text Available Available evidence indicates that the CD6 lymphocyte surface receptor is involved in T-cell developmental and activation processes, by facilitating cell-to-cell adhesive contacts with antigen-presenting cells and likely modulating T-cell receptor (TCR signaling. Here, we show that in vitro activation of human T cells under different TCR-ligation conditions leads to surface downregulation of CD6 expression. This phenomenon was (i concomitant to increased levels of soluble CD6 (sCD6 in culture supernatants, (ii partially reverted by protease inhibitors, (iii not associated to CD6 mRNA down-regulation, and (iv reversible by stimulus removal. CD6 down-modulation inversely correlated with the upregulation of CD25 in both FoxP3− (Tact and FoxP3+ (Treg T-cell subsets. Furthermore, ex vivo analysis of peripheral CD4+ and CD8+ T cells with activated (CD25+ or effector memory (effector memory T cell, CD45RA−CCR7− phenotype present lower CD6 levels than their naïve or central memory (central memory T cell, CD45RA−CCR7+ counterparts. CD6lo/− T cells resulting from in vitro T-cell activation show higher apoptosis and lower proliferation levels than CD6hi T cells, supporting the relevance of CD6 in the induction of proper T-cell proliferative responses and resistance to apoptosis. Accordingly, CD6 transfectants also showed higher viability when exposed to TCR-independent apoptosis-inducing conditions in comparison with untransfected cells. Taken together, these results provide insight into the origin of sCD6 and the previously reported circulating CD6-negative T-cell subset in humans, as well as into the functional consequences of CD6 down-modulation on ongoing T-cell responses, which includes sensitization to apoptotic events and attenuation of T-cell proliferative responses.

  4. Opa+ and Opa- isolates of Neisseria meningitidis and Neisseria gonorrhoeae induce sustained proliferative responses in human CD4+ T cells.

    Science.gov (United States)

    Youssef, Abdel-Rahman; van der Flier, Michiel; Estevão, Silvia; Hartwig, Nico G; van der Ley, Peter; Virji, Mumtaz

    2009-11-01

    T cells may interact with a number of bacterial surface antigens, an encounter which has the potential to downmodulate host immune responses. Neisseria meningitidis, a human colonizer and an agent of septicemia and meningitis, expresses Opa proteins which interact with the CEACAM1 receptor expressed on activated T cells. Since CEACAM1 can act as an inhibitory receptor and T cells in subepithelial tissues may encounter whole bacteria, which often express Opa proteins in vivo, this study assessed primarily if Opa proteins expressed on meningococci affect T-cell functions. In addition, Opa-containing outer membrane vesicles (OMV) have been used as vaccine antigens, and therefore Opa+ and Opa- OMV were also studied. While Opa+ bacteria adhered to CEACAM-expressing T cells, both the Opa+ and Opa- phenotypes induced no to a small transient depression, followed by a prolonged increase in proliferation as well as cytokine production. Such responses were also observed with heat-killed bacteria or OMV. In addition, while anti-CEACAM antibodies alone inhibited proliferation, on coincubation of T cells with bacteria and the antibodies, bacterial effects predominated and were Opa independent. Thus, while Opa proteins of N. meningitidis can bind to T-cell-expressed CEACAM1, this is not sufficient to overcome the T-cell recognition of bacterial factors, which results in a proliferative and cytokine response, an observation consistent with the ability of the host to establish lasting immunity to Opa-expressing meningococci that it frequently encounters. The data also imply that Opa-proficient vaccine preparations may not necessarily inhibit T-cell functions via CEACAM1 binding.

  5. Synergy among rat T cells in the proliferative response to alloantigen

    International Nuclear Information System (INIS)

    Wright, P.W.; Loop, S.M.; Bernstein, I.D.

    1979-01-01

    A synergistic interaction in the proliferative response to alloantigen is described for mixtures of rat thymus and lymph node cells. The optimal conditions for synergy are quantitatively defined. Regression analysis of the slope of the dose-response curve has been utilized to estimate the degree of interaction in thymus--lymph node cell mixtures. The slope of the response of cell mixtures was noted to be significantly greater than the slope for the response of lympth node cells alone. Irradiation was shown to have a differential effect on the response of thymus and lymph node cells in mixtures. Irradiated thymus cells retained the capacity for synergy in mixtures, whereas irradiated lymph node cells did not. Additional studies have demonstrated that both de novo protein synthesis and specific antigen recognition by both responding cell populations in mixtures was required for maximal synergy. These studies demonstrate that synergy cannot be explained as an artifact of altered cell density in vitro. They establish that thymus cells and lymph node cells represent distinct subsets which manifest qualitatively different functions in the proliferative response to alloantigen. Thymus cells can respond directly to alloantigen by proliferation but also have the capacity to amplify the proliferative response of lymph node cells, a capacity which is resistant to X irradiation but requires recognition of alloantigen and de novo protein synthesis. Lymph node cells may similarly respond by proliferation to alloantigen but lack the amplifier activity of thymus cells. Synergy for rat lymphoidcells, like mouse lymphoid cells, has been shown to involve an interaction of thymus-derived lymphocytes

  6. Naturally-acquired influenza-specific CD4+ T-cell proliferative responses are impaired in HIV-infected African adults.

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    Kondwani C Jambo

    Full Text Available Seasonal influenza has been associated with greater morbidity and mortality in AIDS patients. Highly-active antiretroviral therapy (HAART has led to some reduction in influenza-related complications but the nature of naturally-acquired T-cell immunity to influenza virus in an African setting, and how this changes with immune reconstitution following HAART is unknown. We measured influenza-specific CD4(+ T-cell immunity in unimmunized HIV-infected Malawian adults and then investigated immune reconstitution following HAART.Peripheral blood mononuclear cells were isolated from HIV-infected and HIV-uninfected Malawian adults. CFSE proliferation and CD154 expression flow cytometry-based assays were used to measure influenza-specific CD4(+ T-cell immunity.We found lower naturally-acquired proliferative influenza-specific CD4(+ T-cell responses in AIDS patients that was also present in asymptomatic HIV-infected adults with relatively high CD4 counts (>350 cells/µl. Influenza-specific CD4(+ T-cell immune reconstitution in HIV-infected patients on HAART for 12 months was poor despite a marked reduction in viral load and an increase in CD4 count. This poor immune reconstitution was characterised by a low influenza-specific proliferative CD4(+ T-cell response and reduced proportions of CD154-expressing influenza-specific CD4(+ T-cells in peripheral blood.Our data suggest that asymptomatic HIV-infected adults may also be at risk of influenza-related complications and that HAART alone may not circumvent this risk in AIDS patients. This study highlights the need to identify possible interventions early in HIV infection to reduce the risk of influenza and to intensify influenza surveillance in these susceptible African populations.

  7. Opa+ and Opa- isolates of Neisseria meningitidis and Neisseria gonorrhoeae induce sustained proliferative responses in human CD4+ T cells.

    NARCIS (Netherlands)

    Youssef, A.R.; Flier, M. van der; Estevao, S.; Hartwig, N.G.; Ley, P. van der; Virji, M.

    2009-01-01

    T cells may interact with a number of bacterial surface antigens, an encounter which has the potential to downmodulate host immune responses. Neisseria meningitidis, a human colonizer and an agent of septicemia and meningitis, expresses Opa proteins which interact with the CEACAM1 receptor expressed

  8. Peripheral blood T cell proliferative response to chlamydial organisms in gonococcal and non-gonococcal urethritis and presumed pelvic inflammatory disease

    Science.gov (United States)

    Shahmanesh, M.; Brunst, M.; Sukthankar, A.; Pearce, J. H.; Gaston, J. S.

    1999-01-01

    OBJECTIVE: To study peripheral blood mononuclear cell (PBMC) proliferative response to Chlamydia trachomatis elementary bodies in (a) controls, (b) various stages of gonococcal (c) and non-gonococcal urethritis, and (d) women with a clinical diagnosis of pelvic inflammatory disease (PID). METHODS: We categorised 102 men presenting to a GUM clinic with urethritis by organisms (C trachomatis (CT) or Neisseria gonorrhoeae (NG) (both by culture), and whether it was their first (urethritis naive) or subsequent (urethritis experienced) attack. 23 women presenting to the clinic with a clinical diagnosis of PID were also investigated. We measured PBMC proliferative responses to C trachomatis (DK20--an oculogenital strain, serovar E), lysate of McCoy cells (used to propagate chlamydiae), and the recall antigen PPD. Controls were 37 men and women without present or past history of urethritis or chlamydial infection. Results were expressed as the ratio of the stimulation index (SI) obtained with DK20 compared with McCoy cells (DK index), and the ratio of the SI obtained with DK20 compared with PPD (PPD index). RESULTS: The median SI to DK20 in the urethritis was 12.7 which was significantly higher than the controls (7.6, p urethritis patients (17.4) and the controls (22.4). All urethritis patient subgroups had a significantly higher DK index and PPD index than the controls. There was no difference in the PPD and DK index between urethritis naive and urethritis experienced patients and between the culture positive and culture negative urethritis subgroups. In PID patients only the PPD index was significantly higher than the controls. CONCLUSION: Men presenting with urethritis and women presenting with PID both have significantly greater peripheral blood mononuclear cell proliferative responses to the DK20 strain of C trachomatis than controls. A similar T cell proliferative response pattern in urethritis naive patients with either gonococcal or non-gonococcal urethritis could

  9. MiR-155 is overexpressed in patients with atopic dermatitis and modulates T-cell proliferative responses by targeting cytotoxic T lymphocyte-associated antigen 4

    DEFF Research Database (Denmark)

    Sonkoly, Enikö; Janson, Peter; Majuri, Marja-Leena

    2010-01-01

    MicroRNAs (miRNAs) are short noncoding RNAs that suppress gene expression at the posttranscriptional level. Atopic dermatitis is a common chronic inflammatory skin disease characterized by the presence of activated T cells within the skin....

  10. Regulation of T cell responses in atherosclerosis

    NARCIS (Netherlands)

    Puijvelde, Gijsbrecht Henricus Maria van

    2007-01-01

    One of the most important characteristics of atherosclerosis is the chronic inflammatory response in which T cells and NKT cells are very important. In this thesis several methods to modulate the activity of these T and NKT cells in atherosclerosis are described. The induction of regulatory T cells

  11. Mechanisms of HIV non-progression; robust and sustained CD4+ T-cell proliferative responses to p24 antigen correlate with control of viraemia and lack of disease progression after long-term transfusion-acquired HIV-1 infection

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    Geczy Andrew F

    2008-12-01

    Full Text Available Abstract Background Elite non-progressors (plasma viral load Results A survival advantage was conferred on 12 of 13 subjects, who had at least one host genetic factor (HLA, chemokine receptor or TLR polymorphisms or viral attenuating factor (defective nef associated with slow progression. However, antiviral immune responses differentiated the course of disease into and beyond the second decade of infection. A stable p24-specific proliferative response was associated with control of viraemia and retention of non-progressor status, but this p24 response was absent or declined in viraemic subjects. Strong Gag-dominant cytotoxic T lymphocyte (CTL responses were identified in most LTNP, or Pol dominant-CTL in those with nef-defective HIV infection. CTL were associated with control of viraemia when combined with p24 proliferative responses. However, CTL did not prevent late disease progression. Individuals with sustained viral suppression had CTL recognising numerous Gag epitopes, while strong but restricted responses to one or two immunodominant epitopes was effective for some time, but failed to contain viraemia over the course of this study. Viral escape mutants at a HLA B27-restricted Gag-p24 epitope were detected in only 1 of 3 individuals, whereas declining or negative p24 proliferative responses occurred in all 3 concurrent with an increase in viraemia. Conclusion Detectable viraemia at study entry was predictive of loss of LTNP status and/or disease progression in 6 of 8, and differentiated slow progressors from elite LTNP who retained potent virological control. Sustained immunological suppression of viraemia was independently associated with preserved p24 proliferative responses, regardless of the strength and breadth of the CTL response. A decline in this protective p24 response preceded or correlated with loss of non-progressor status and/or signs of disease progression.

  12. Presence of Antigen-Experienced T Cells with Low Grade of Differentiation and Proliferative Potential in Chronic Chagas Disease Myocarditis

    Science.gov (United States)

    Cabeza-Meckert, Patricia; Viotti, Rodolfo; Garelli, Fernando; Favaloro, Liliana E.; Favaloro, Roberto R.; Laguens, Rubén; Laucella, Susana A.

    2014-01-01

    Background The main consequence of chronic Trypanosoma cruzi infection is the development of myocarditis in approximately 20–30% of infected individuals but not until 10–20 years after the initial infection. We have previously shown that circulating interferon-γ-secreting T cells responsive to Trypanosoma cruzi antigens in chronic Chagas disease patients display a low grade of differentiation and the frequency of these T lymphocytes decreases along with the severity of heart disease. This study thought to explore the expression of inhibitory receptors, transcription factors of type 1 or regulatory T cells, and markers of T cell differentiation, immunosenescence or active cell cycle in cardiac explants from patients with advanced Chagas disease myocarditis. Methodology/Principal Findings The expression of different markers for T and B cells as well as for macrophages was evaluated by immunohistochemistry and immunofluorescence techniques in cardiac explants from patients with advanced chronic Chagas disease submitted to heart transplantation. Most infiltrating cells displayed markers of antigen-experienced T cells (CD3+, CD4+, CD8+, CD45RO+) with a low grade of differentiation (CD27+, CD57−, CD45RA−, PD-1−). A skewed T helper1/T cytotoxic 1 profile was supported by the expression of T-bet; whereas FOXP3+ cells were scarce and located only in areas of severe myocarditis. In addition, a significant proliferative capacity of CD3+ T cells, assessed by Ki67 staining, was found. Conclusions/Significance The quality of T cell responses and immunoregulatory mechanisms might determine the pattern of the cellular response and the severity of disease in chronic Trypanosoma cruzi infection. PMID:25144227

  13. Regulatory CD4+CD25+ T cells restrict memory CD8+ T cell responses.

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    Kursar, Mischo; Bonhagen, Kerstin; Fensterle, Joachim; Köhler, Anne; Hurwitz, Robert; Kamradt, Thomas; Kaufmann, Stefan H E; Mittrücker, Hans-Willi

    2002-12-16

    CD4+ T cell help is important for the generation of CD8+ T cell responses. We used depleting anti-CD4 mAb to analyze the role of CD4+ T cells for memory CD8+ T cell responses after secondary infection of mice with the intracellular bacterium Listeria monocytogenes, or after boost immunization by specific peptide or DNA vaccination. Surprisingly, anti-CD4 mAb treatment during secondary CD8+ T cell responses markedly enlarged the population size of antigen-specific CD8+ T cells. After boost immunization with peptide or DNA, this effect was particularly profound, and antigen-specific CD8+ T cell populations were enlarged at least 10-fold. In terms of cytokine production and cytotoxicity, the enlarged CD8+ T cell population consisted of functional effector T cells. In depletion and transfer experiments, the suppressive function could be ascribed to CD4+CD25+ T cells. Our results demonstrate that CD4+ T cells control the CD8+ T cell response in two directions. Initially, they promote the generation of a CD8+ T cell responses and later they restrain the strength of the CD8+ T cell memory response. Down-modulation of CD8+ T cell responses during infection could prevent harmful consequences after eradication of the pathogen.

  14. T-cell responses in malaria

    DEFF Research Database (Denmark)

    Hviid, L; Jakobsen, P H; Abu-Zeid, Y A

    1992-01-01

    vaccine. Despite this, no efficient operative vaccine is currently available. A large amount of information on T-cell responses to malaria antigens has been accumulated, concerning antigens derived from all stages of the parasite life cycle. The present review summarizes some of that information......Malaria is caused by infection with protozoan parasites of the genus Plasmodium. It remains one of the most severe health problems in tropical regions of the world, and the rapid spread of resistance to drugs and insecticides has stimulated intensive research aimed at the development of a malaria......, and discusses factors affecting the responses of T cells to malaria antigens....

  15. T-cell responses in malaria

    DEFF Research Database (Denmark)

    Hviid, L; Jakobsen, P H; Abu-Zeid, Y A

    1992-01-01

    Malaria is caused by infection with protozoan parasites of the genus Plasmodium. It remains one of the most severe health problems in tropical regions of the world, and the rapid spread of resistance to drugs and insecticides has stimulated intensive research aimed at the development of a malaria...... vaccine. Despite this, no efficient operative vaccine is currently available. A large amount of information on T-cell responses to malaria antigens has been accumulated, concerning antigens derived from all stages of the parasite life cycle. The present review summarizes some of that information......, and discusses factors affecting the responses of T cells to malaria antigens....

  16. T-cell response in human leishmaniasis

    DEFF Research Database (Denmark)

    Kharazmi, A; Kemp, K; Ismail, A

    1999-01-01

    from cutaneous leishmaniasis (CL) responded by IFN-gamma production following stimulation with Leishmania antigens whereas cells from patients recovered from visceral leishmaniasis (VL) showed a mixed pattern of IFN-gamma and IL-4 responses. The cells producing these cytokines were predominantly CD4......In the present communication we provide evidence for the existence of a Th1/Th2 dichotomy in the T-cell response to Leishmania antigens in human leishmaniasis. Our data suggest that the pattern of IL-4 and IFN-gamma response is polarised in these patients. Lymphocytes from individuals recovered......+. Furthermore, IL-10 plays an important role in the development of post kala azar dermal leishmaniasis (PKDL) from VL. The balance between the parasitic-specific T-cell response plays an important regulatory role in determining the outcome of Leishmania infections in humans....

  17. T-cell response in human leishmaniasis

    DEFF Research Database (Denmark)

    Kharazmi, A; Kemp, K; Ismail, A

    1999-01-01

    In the present communication we provide evidence for the existence of a Th1/Th2 dichotomy in the T-cell response to Leishmania antigens in human leishmaniasis. Our data suggest that the pattern of IL-4 and IFN-gamma response is polarised in these patients. Lymphocytes from individuals recovered...... from cutaneous leishmaniasis (CL) responded by IFN-gamma production following stimulation with Leishmania antigens whereas cells from patients recovered from visceral leishmaniasis (VL) showed a mixed pattern of IFN-gamma and IL-4 responses. The cells producing these cytokines were predominantly CD4......+. Furthermore, IL-10 plays an important role in the development of post kala azar dermal leishmaniasis (PKDL) from VL. The balance between the parasitic-specific T-cell response plays an important regulatory role in determining the outcome of Leishmania infections in humans....

  18. Dysregulation of T lymphocyte proliferative responses in autoimmunity.

    Directory of Open Access Journals (Sweden)

    Sydney K Elizer

    Full Text Available T cells are critically dependent on cellular proliferation in order to carry out their effector functions. Autoimmune strains are commonly thought to have uncontrolled T cell proliferation; however, in the murine model of autoimmune diabetes, hypo-proliferation of T cells leading to defective AICD was previously uncovered. We now determine whether lupus prone murine strains are similarly hyporesponsive. Upon extensive characterization of T lymphocyte activation, we have observed a common feature of CD4 T cell activation shared among three autoimmune strains-NOD, MRL, and NZBxNZW F1s. When stimulated with a polyclonal mitogen, CD4 T cells demonstrate arrested cell division and diminished dose responsiveness as compared to the non-autoimmune strain C57BL/6, a phenotype we further traced to a reliance on B cell mediated costimulation, which underscores the success of B cell directed immune therapies in preventing T cell mediated tissue injury. In turn, the diminished proliferative capacity of these CD4 T cells lead to a decreased, but activation appropriate, susceptibility to activation induced cell death. A similar decrement in stimulation response was observed in the CD8 compartment of NOD mice; NOD CD8 T cells were distinguished from lupus prone strains by a diminished dose-responsiveness to anti-CD3 mediated stimulation. This distinction may explain the differential pathogenetic pathways activated in diabetes and lupus prone murine strains.

  19. The T Cell Response to Staphylococcus aureus

    Science.gov (United States)

    Bröker, Barbara M.; Mrochen, Daniel; Péton, Vincent

    2016-01-01

    Staphylococcus aureus (S. aureus) is a dangerous pathogen and a leading cause of both nosocomial and community acquired bacterial infection worldwide. However, on the other hand, we are all exposed to this bacterium, often within the first hours of life, and usually manage to establish equilibrium and coexist with it. What does the adaptive immune system contribute toward lifelong control of S. aureus? Will it become possible to raise or enhance protective immune memory by vaccination? While in the past the S. aureus-specific antibody response has dominated this discussion, the research community is now coming to appreciate the role that the cellular arm of adaptive immunity, the T cells, plays. There are numerous T cell subsets, each with differing functions, which together have the ability to orchestrate the immune response to S. aureus and hence to tip the balance between protection and pathology. This review summarizes the state of the art in this dynamic field of research. PMID:26999219

  20. Respiratory syncytial virus-specific CD8(+) memory T cell responses in elderly persons

    NARCIS (Netherlands)

    de Bree, GJ; Heidema, J; van Leeuwen, EMM; van Bleek, GM; Jonkers, RE; Jansen, HM; van Lier, RAW; Out, TA

    2005-01-01

    Background. We investigated respiratory syncytial virus (RSV)-specific CD8(+) memory T cell responses in healthy control participants (n = 31) and in patients with chronic obstructive pulmonary disease (COPD) n = 9), with respect to frequency, memory phenotype, and proliferative requirements.

  1. Regulatory T Cells in Radiotherapeutic Responses

    International Nuclear Information System (INIS)

    Schaue, Dörthe; Xie, Michael W.; Ratikan, Josephine A.; McBride, William H.

    2012-01-01

    Radiation therapy (RT) can extend its influence in cancer therapy beyond what can be attributed to in-field cytotoxicity by modulating the immune system. While complex, these systemic effects can help tip the therapeutic balance in favor of treatment success or failure. Engagement of the immune system is generally through recognition of damage-associated molecules expressed or released as a result of tumor and normal tissue radiation damage. This system has evolved to discriminate pathological from physiological forms of cell death by signaling “danger.” The multiple mechanisms that can be evoked include a shift toward a pro-inflammatory, pro-oxidant microenvironment that can promote maturation of dendritic cells and, in cancer treatment, the development of effector T cell responses to tumor-associated antigens. Control over these processes is exerted by regulatory T cells (Tregs), suppressor macrophages, and immunosuppressive cytokines that act in consort to maintain tolerance to self, limit tissue damage, and re-establish tissue homeostasis. Unfortunately, by the time RT for cancer is initiated the tumor-host relationship has already been sculpted in favor of tumor growth and against immune-mediated mechanisms for tumor regression. Reversing this situation is a major challenge. However, recent data show that removal of Tregs can tip the balance in favor of the generation of radiation-induced anti-tumor immunity. The clinical challenge is to do so without excessive depletion that might precipitate serious autoimmune reactions and increase the likelihood of normal tissue complications. The selective modulation of Treg biology to maintain immune tolerance and control of normal tissue damage, while releasing the “brakes” on anti-tumor immune responses, is a worthy aim with promise for enhancing the therapeutic benefit of RT for cancer.

  2. Regulatory T cells in radiotherapeutic responses

    Directory of Open Access Journals (Sweden)

    Dörthe eSchaue

    2012-08-01

    Full Text Available Radiation therapy (RT can extend its influence in cancer therapy beyond what can be attributed to in-field cytotoxicity by modulating the immune system. While complex, these systemic effects can help tip the therapeutic balance in favor of treatment success or failure. Engagement of the immune system is generally through recognition of damage-associated molecules expressed or released as a result of tumor and normal tissue radiation damage. This system has evolved to discriminate pathological from physiological forms of cell death by signaling danger. The multiple mechanisms that can be evoked include a shift towards a pro-inflammatory, pro-oxidant microenvironment that can promote maturation of dendritic cells and, in cancer treatment, the development of effector T cell responses to tumor-associated antigens. Control over these processes is exerted by regulatory T cells (Tregs, suppressor macrophages and immunosuppressive cytokines that act in consort to maintain tolerance to self, limit tissue damage, and re-establish tissue homeostasis. Unfortunately, by the time RT for cancer is initiated the tumor-host relationship has already been sculpted in favor of tumor growth and against immune-mediated mechanisms for tumor regression. Reversing this situation is a major challenge. However, recent data show that removal of Tregs can tip the balance in favor of the generation of radiation-induced anti-tumor immunity. The clinical challenge is to do so without excessive depletion that might precipitate serious autoimmune reactions and increase the likelihood of normal tissue complications. The selective modulation of Treg biology to maintain immune tolerance and control of normal tissue damage, while releasing the brakes on anti-tumor immune responses, is a worthy aim with promise for enhancing the therapeutic benefit of RT for cancer.

  3. [CD4+ alpha beta T cell and gamma delta T cell responses to BCG in patients with pulmonary tuberculosis--comparison with healthy controls].

    Science.gov (United States)

    Tsukaguchi, K; Okamura, H; Tokuyama, T; Okamoto, Y; Fu, A; Yamamoto, C; Nakaya, M; Kobayashi, A; Yoneda, T; Narita, N

    1997-12-01

    We demonstrated that CD4+ alpha beta (CD4+) and gamma delta T cell subsets from healthy donors had similar effector functions (cytotoxicity and cytokine production) in response to mycobacterial antigens, despite differences in the antigens recognized. To elucidate the pathogenesis of pulmonary tuberculosis, this study was undertaken to compare T cell functions between patients with pulmonary tuberculosis with no complications and healthy controls. Both resting and activated CD4+ and gamma delta T cells from the patient group proliferated in response to live BCG at a significantly lower rate than those from the control group. The cytotoxicity of BCG-pulsed monocytes and IFN-gamma production in both the CD4+ and gamma delta T cells from patients was significantly lower than those of controls. In contrast to IFN-gamma, significantly higher IL-10 production by both CD4+ and gamma delta T cells from patients was detected. The proliferative responses to BCG by CD4+ and gamma delta T cells from patients after antituberculous therapy were partially restored, but remained at lower levels compared with controls. These results suggest that not only a general deterioration in CD4+ and gamma delta T cells effector functions, but also suppressive factors (such as IL-10) might be responsible for the pathogenesis of pulmonary tuberculosis, and that the low response to BCG by both CD4+ and gamma delta T cells in patients with tuberculosis is in part attributable to patient predisposition.

  4. Murine Lung Cancer Increases CD4+ T Cell Apoptosis and Decreases Gut Proliferative Capacity in Sepsis.

    Science.gov (United States)

    Lyons, John D; Mittal, Rohit; Fay, Katherine T; Chen, Ching-Wen; Liang, Zhe; Margoles, Lindsay M; Burd, Eileen M; Farris, Alton B; Ford, Mandy L; Coopersmith, Craig M

    2016-01-01

    Mortality is significantly higher in septic patients with cancer than in septic patients without a history of cancer. We have previously described a model of pancreatic cancer followed by sepsis from Pseudomonas aeruginosa pneumonia in which cancer septic mice have higher mortality than previously healthy septic mice, associated with increased gut epithelial apoptosis and decreased T cell apoptosis. The purpose of this study was to determine whether this represents a common host response by creating a new model in which both the type of cancer and the model of sepsis are altered. C57Bl/6 mice received an injection of 250,000 cells of the lung cancer line LLC-1 into their right thigh and were followed three weeks for development of palpable tumors. Mice with cancer and mice without cancer were then subjected to cecal ligation and puncture and sacrificed 24 hours after the onset of sepsis or followed 7 days for survival. Cancer septic mice had a higher mortality than previously healthy septic mice (60% vs. 18%, p = 0.003). Cancer septic mice had decreased number and frequency of splenic CD4+ lymphocytes secondary to increased apoptosis without changes in splenic CD8+ numbers. Intestinal proliferation was also decreased in cancer septic mice. Cancer septic mice had a higher bacterial burden in the peritoneal cavity, but this was not associated with alterations in local cytokine, neutrophil or dendritic cell responses. Cancer septic mice had biochemical evidence of worsened renal function, but there was no histologic evidence of renal injury. Animals with cancer have a significantly higher mortality than previously healthy animals following sepsis. The potential mechanisms associated with this elevated mortality differ significantly based upon the model of cancer and sepsis utilized. While lymphocyte apoptosis and intestinal integrity are both altered by the combination of cancer and sepsis, the patterns of these alterations vary greatly depending on the models used.

  5. Murine Lung Cancer Increases CD4+ T Cell Apoptosis and Decreases Gut Proliferative Capacity in Sepsis.

    Directory of Open Access Journals (Sweden)

    John D Lyons

    Full Text Available Mortality is significantly higher in septic patients with cancer than in septic patients without a history of cancer. We have previously described a model of pancreatic cancer followed by sepsis from Pseudomonas aeruginosa pneumonia in which cancer septic mice have higher mortality than previously healthy septic mice, associated with increased gut epithelial apoptosis and decreased T cell apoptosis. The purpose of this study was to determine whether this represents a common host response by creating a new model in which both the type of cancer and the model of sepsis are altered.C57Bl/6 mice received an injection of 250,000 cells of the lung cancer line LLC-1 into their right thigh and were followed three weeks for development of palpable tumors. Mice with cancer and mice without cancer were then subjected to cecal ligation and puncture and sacrificed 24 hours after the onset of sepsis or followed 7 days for survival.Cancer septic mice had a higher mortality than previously healthy septic mice (60% vs. 18%, p = 0.003. Cancer septic mice had decreased number and frequency of splenic CD4+ lymphocytes secondary to increased apoptosis without changes in splenic CD8+ numbers. Intestinal proliferation was also decreased in cancer septic mice. Cancer septic mice had a higher bacterial burden in the peritoneal cavity, but this was not associated with alterations in local cytokine, neutrophil or dendritic cell responses. Cancer septic mice had biochemical evidence of worsened renal function, but there was no histologic evidence of renal injury.Animals with cancer have a significantly higher mortality than previously healthy animals following sepsis. The potential mechanisms associated with this elevated mortality differ significantly based upon the model of cancer and sepsis utilized. While lymphocyte apoptosis and intestinal integrity are both altered by the combination of cancer and sepsis, the patterns of these alterations vary greatly depending on

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

    Science.gov (United States)

    León, Beatriz; Ballesteros-Tato, André; Randall, Troy D.

    2014-01-01

    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. PMID:25002751

  7. MMP19 is essential for T cell development and T cell-mediated cutaneous immune responses

    Czech Academy of Sciences Publication Activity Database

    Beck, Inken; Ruckert, R.; Brandt, K.; Mueller, M.S.; Sadowski, T.; Brauer, R.; Schirmacher, P.; Mentlein, R.; Sedláček, Radislav

    2008-01-01

    Roč. 3, č. 6 (2008), e2343-e2343 E-ISSN 1932-6203 Institutional research plan: CEZ:AV0Z50520514; CEZ:AV0Z50520701 Keywords : matrix metalloproteinase * T cell * immune response Subject RIV: EB - Genetics ; Molecular Biology

  8. T Cell Responses: Naive to Memory and Everything in Between

    Science.gov (United States)

    Pennock, Nathan D.; White, Jason T.; Cross, Eric W.; Cheney, Elizabeth E.; Tamburini, Beth A.; Kedl, Ross M.

    2013-01-01

    The authors describe the actions that take place in T cells because of their amazing capacity to proliferate and adopt functional roles aimed at clearing a host of an infectious agent. There is a drastic decline in the T cell population once the primary response is over and the infection is terminated. What remains afterward is a population of T…

  9. Similar Responses of Intestinal T Cells From Untreated Children and Adults With Celiac Disease to Deamidated Gluten Epitopes.

    Science.gov (United States)

    Ráki, Melinda; Dahal-Koirala, Shiva; Yu, Hao; Korponay-Szabó, Ilma R; Gyimesi, Judit; Castillejo, Gemma; Jahnsen, Jørgen; Qiao, Shuo-Wang; Sollid, Ludvig M

    2017-09-01

    Celiac disease is a chronic small intestinal inflammatory disorder mediated by an immune response to gluten peptides in genetically susceptible individuals. Celiac disease is often diagnosed in early childhood, but some patients receive a diagnosis late in life. It is uncertain whether pediatric celiac disease is distinct from adult celiac disease. It has been proposed that gluten-reactive T cells in children recognize deamidated and native gluten epitopes, whereas T cells from adults only recognize deamidated gluten peptides. We studied the repertoire of gluten epitopes recognized by T cells from children and adults. We examined T-cell responses against gluten by generating T-cell lines and T-cell clones from intestinal biopsies of adults and children and tested proliferative response to various gluten peptides. We analyzed T cells from 14 children (2-5 years old) at high risk for celiac disease who were followed for celiac disease development. We also analyzed T cells from 6 adults (26-55 years old) with untreated celiac disease. All children and adults were positive for HLA-DQ2.5. Biopsies were incubated with gluten digested with chymotrypsin (modified or unmodified by the enzyme transglutaminase 2) or the peptic-tryptic digest of gliadin (in native and deamidated forms) before T-cell collection. Levels of T-cell responses were higher to deamidated gluten than to native gluten in children and adults. T cells from children and adults each reacted to multiple gluten epitopes. Several T-cell clones were cross-reactive, especially clones that recognized epitopes from γ-and ω-gliadin. About half of the generated T-cell clones from children and adults reacted to unknown epitopes. T-cell responses to different gluten peptides appear to be similar between adults and children at the time of diagnosis of celiac disease. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  10. To investigate the necessity of STRA6 upregulation in T cells during T cell immune responses.

    Directory of Open Access Journals (Sweden)

    Rafik Terra

    Full Text Available Our earlier study revealed that STRA6 (stimulated by retinoic acid gene 6 was up-regulated within 3 h of TCR stimulation. STRA6 is the high-affinity receptor for plasma retinol-binding protein (RBP and mediates cellular vitamin A uptake. We generated STRA6 knockout (KO mice to assess whether such up-regulation was critical for T-cell activation, differentiation and function. STRA6 KO mice under vitamin A sufficient conditions were fertile without apparent anomalies upon visual inspection. The size, cellularity and lymphocyte subpopulations of STRA6 KO thymus and spleen were comparable to those of their wild type (WT controls. KO and WT T cells were similar in terms of TCR-stimulated proliferation in vitro and homeostatic expansion in vivo. Naive KO CD4 cells differentiated in vitro into Th1, Th2, Th17 as well as regulatory T cells in an analogous manner as their WT counterparts. In vivo experiments revealed that anti-viral immune responses to lymphocytic choriomeningitis virus in KO mice were comparable to those of WT controls. We also demonstrated that STRA6 KO and WT mice had similar glucose tolerance. Total vitamin A levels are dramatically lower in the eyes of KO mice as compared to those of WT mice, but the levels in other organs were not significantly affected after STRA6 deletion under vitamin A sufficient conditions, indicating that the eye is the mouse organ most sensitive to the loss of STRA6. Our results demonstrate that 1 in vitamin A sufficiency, the deletion of STRA6 in T cells does no affect the T-cell immune responses so-far tested, including those depend on STAT5 signaling; 2 STRA6-independent vitamin A uptake compensated the lack of STRA6 in lymphoid organs under vitamin A sufficient conditions in mice; 3 STRA6 is critical for vitamin A uptake in the eyes even in vitamin A sufficiency.

  11. Flow cytometric assessment of chicken T cell-mediated immune responses after Newcastle disease virus vaccination and challenge

    DEFF Research Database (Denmark)

    Dalgaard, T. S.; Norup, L. R.; Pedersen, A.R.

    2010-01-01

    . Despite a delayed NDV-specific antibody response to vaccination, L133 appeared to be better protected than L130 in the subsequent infection challenge as determined by the presence of viral genomes. Peripheral blood was analyzed by flow cytometry and responses in vaccinated/challenged birds were studied...... by 5-color immunophenotyping as well as by measuring the proliferative capacity of NDV-specific T cells after recall stimulation. Immunophenotyping identified L133 as having a significantly lower CD4/CD8 ratio and a lower frequency of γδ T cells than L130 in the peripheral T cell compartment...

  12. ZFAT plays critical roles in peripheral T cell homeostasis and its T cell receptor-mediated response

    International Nuclear Information System (INIS)

    Doi, Keiko; Fujimoto, Takahiro; Okamura, Tadashi; Ogawa, Masahiro; Tanaka, Yoko; Mototani, Yasumasa; Goto, Motohito; Ota, Takeharu; Matsuzaki, Hiroshi; Kuroki, Masahide; Tsunoda, Toshiyuki; Sasazuki, Takehiko; Shirasawa, Senji

    2012-01-01

    Highlights: ► We generated Cd4-Cre-mediated T cell-specific Zfat-deficient mice. ► Zfat-deficiency leads to reduction in the number of the peripheral T cells. ► Impaired T cell receptor-mediated response in Zfat-deficient peripheral T cells. ► Decreased expression of IL-7Rα, IL-2Rα and IL-2 in Zfat-deficient peripheral T cells. ► Zfat plays critical roles in peripheral T cell homeostasis. -- Abstract: ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in apoptosis, development and primitive hematopoiesis. Zfat is highly expressed in T- and B-cells in the lymphoid tissues, however, its physiological function in the immune system remains totally unknown. Here, we generated the T cell-specific Zfat-deficient mice and demonstrated that Zfat-deficiency leads to a remarkable reduction in the number of the peripheral T cells. Intriguingly, a reduced expression of IL-7Rα and the impaired responsiveness to IL-7 for the survival were observed in the Zfat-deficient T cells. Furthermore, a severe defect in proliferation and increased apoptosis in the Zfat-deficient T cells following T cell receptor (TCR) stimulation was observed with a reduced IL-2Rα expression as well as a reduced IL-2 production. Thus, our findings reveal that Zfat is a critical regulator in peripheral T cell homeostasis and its TCR-mediated response.

  13. CD28 expression is required after T cell priming for helper T cell responses and protective immunity to infection.

    Science.gov (United States)

    Linterman, Michelle A; Denton, Alice E; Divekar, Devina P; Zvetkova, Ilona; Kane, Leanne; Ferreira, Cristina; Veldhoen, Marc; Clare, Simon; Dougan, Gordon; Espéli, Marion; Smith, Kenneth G C

    2014-10-27

    The co-stimulatory molecule CD28 is essential for activation of helper T cells. Despite this critical role, it is not known whether CD28 has functions in maintaining T cell responses following activation. To determine the role for CD28 after T cell priming, we generated a strain of mice where CD28 is removed from CD4(+) T cells after priming. We show that continued CD28 expression is important for effector CD4(+) T cells following infection; maintained CD28 is required for the expansion of T helper type 1 cells, and for the differentiation and maintenance of T follicular helper cells during viral infection. Persistent CD28 is also required for clearance of the bacterium Citrobacter rodentium from the gastrointestinal tract. Together, this study demonstrates that CD28 persistence is required for helper T cell polarization in response to infection, describing a novel function for CD28 that is distinct from its role in T cell priming.

  14. Exposure to inhaled isobutyl nitrite reduces T cell-dependent responsiveness

    Energy Technology Data Exchange (ETDEWEB)

    Soderberg, L.S.F.; Barnett, J.B. (Univ. of Arkansas, Little Rock (United States))

    1991-03-11

    Isobutyl nitrite is a drug of abuse popular among male homosexuals and among adolescents. In order to approximate the nitrite exposures of inhalant abusers, mice were treated with 900 ppm isobutyl nitrite in an inhalation chamber for 45 min per day for 14 days. At 72 hr after the last exposure, mice were assayed for immune competence. Under these conditions, mice gained only half the weight of mice exposed to air. The spleens of nitrite exposed mice weighed 15% less and had 24% fewer cells per spleen than controls. Adjusted for equal cell numbers, T cell mitogenic and allogeneic proliferative responses were significantly reduce by 33% and 47%, respectively. Unstimulated spleen cells had elevated levels of IL-2 transcription following exposure to isobutyl nitrite suggesting that nitrite inhalation caused a nonspecific induction of T cells. In contrast, B cell proliferative responses to LPS were unaltered. Exposure to the nitrite reduced the frequency of T-dependent antibody plaque-forming cells (PFC) by 63% and the total number of reduced by 60% after as few as five daily exposures to isobutyl nitrite. Therefore, the data suggest that habitual inhalation of isobutyl nitrite impairs immune competence and that toxicity appears to be directed toward T cell functions.

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Regulatory T Cells and Host Anti-CML Responses

    National Research Council Canada - National Science Library

    Wong, Jr, K. K

    2008-01-01

    CD4+CD25+FoxP-3+ regulatory T-cells (Tregs) suppress immune responses to "self" antigens, but also have been shown to suppress host anti-tumor responses in several human malignancies, including breast, gastrointestinal, and ovarian cancer...

  17. ZFAT plays critical roles in peripheral T cell homeostasis and its T cell receptor-mediated response

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Keiko [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute of Life Sciences for the Next Generation of Women Scientists, Fukuoka University, Fukuoka (Japan); Fujimoto, Takahiro [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Okamura, Tadashi [Division of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo (Japan); Ogawa, Masahiro [Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Tanaka, Yoko [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Mototani, Yasumasa; Goto, Motohito [Division of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo (Japan); Ota, Takeharu; Matsuzaki, Hiroshi [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Kuroki, Masahide [Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Tsunoda, Toshiyuki [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Sasazuki, Takehiko [Institute for Advanced Study, Kyushu University, Fukuoka (Japan); Shirasawa, Senji, E-mail: sshirasa@fukuoka-u.ac.jp [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan)

    2012-08-17

    Highlights: Black-Right-Pointing-Pointer We generated Cd4-Cre-mediated T cell-specific Zfat-deficient mice. Black-Right-Pointing-Pointer Zfat-deficiency leads to reduction in the number of the peripheral T cells. Black-Right-Pointing-Pointer Impaired T cell receptor-mediated response in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Decreased expression of IL-7R{alpha}, IL-2R{alpha} and IL-2 in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Zfat plays critical roles in peripheral T cell homeostasis. -- Abstract: ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in apoptosis, development and primitive hematopoiesis. Zfat is highly expressed in T- and B-cells in the lymphoid tissues, however, its physiological function in the immune system remains totally unknown. Here, we generated the T cell-specific Zfat-deficient mice and demonstrated that Zfat-deficiency leads to a remarkable reduction in the number of the peripheral T cells. Intriguingly, a reduced expression of IL-7R{alpha} and the impaired responsiveness to IL-7 for the survival were observed in the Zfat-deficient T cells. Furthermore, a severe defect in proliferation and increased apoptosis in the Zfat-deficient T cells following T cell receptor (TCR) stimulation was observed with a reduced IL-2R{alpha} expression as well as a reduced IL-2 production. Thus, our findings reveal that Zfat is a critical regulator in peripheral T cell homeostasis and its TCR-mediated response.

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

    Directory of Open Access Journals (Sweden)

    Scott W McPherson

    2012-06-01

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

  19. Metabolic reprogramming towards aerobic glycolysis correlates with greater proliferative ability and resistance to metabolic inhibition in CD8 versus CD4 T cells.

    Directory of Open Access Journals (Sweden)

    Yilin Cao

    Full Text Available T lymphocytes (T cells undergo metabolic reprogramming after activation to provide energy and biosynthetic materials for growth, proliferation and differentiation. Distinct T cell subsets, however, adopt metabolic programs specific to support their needs. As CD4 T cells coordinate adaptive immune responses while CD8 T cells become cytotoxic effectors, we compared activation-induced proliferation and metabolic reprogramming of these subsets. Resting CD4 and CD8 T cells were metabolically similar and used a predominantly oxidative metabolism. Following activation CD8 T cells proliferated more rapidly. Stimulation led both CD4 and CD8 T cells to sharply increase glucose metabolism and adopt aerobic glycolysis as a primary metabolic program. Activated CD4 T cells, however, remained more oxidative and had greater maximal respiratory capacity than activated CD8 T cells. CD4 T cells were also associated with greater levels of ROS and increased mitochondrial content, irrespective of the activation context. CD8 cells were better able, however, to oxidize glutamine as an alternative fuel source. The more glycolytic metabolism of activated CD8 T cells correlated with increased capacity for growth and proliferation, along with reduced sensitivity of cell growth to metabolic inhibition. These specific metabolic programs may promote greater growth and proliferation of CD8 T cells and enhance survival in diverse nutrient conditions.

  20. Healthy human T-Cell Responses to Aspergillus fumigatus antigens.

    Directory of Open Access Journals (Sweden)

    Neelkamal Chaudhary

    2010-02-01

    Full Text Available Aspergillus fumigatus is associated with both invasive and allergic pulmonary diseases, in different hosts. The organism is inhaled as a spore, which, if not cleared from the airway, germinates into hyphal morphotypes that are responsible for tissue invasion and resultant inflammation. Hyphae secrete multiple products that function as antigens, evoking both a protective (T(H1-T(H17 and destructive allergic (T(H2 immunity. How Aspergillus allergens (Asp f proteins participate in the development of allergic sensitization is unknown.To determine whether Asp f proteins are strictly associated with T(H2 responses, or represent soluble hyphal products recognized by healthy hosts, human T cell responses to crude and recombinant products were characterized by ELISPOT. While responses (number of spots producing IFN-gamma, IL-4 or IL-17 to crude hyphal antigen preparations were weak, responses to recombinant Asp f proteins were higher. Recombinant allergens stimulated cells to produce IFN-gamma more so than IL-4 or IL-17. Volunteers exhibited a diverse CD4+ and CD8+ T cell antigen recognition profile, with prominent CD4 T(H1-responses to Asp f3 (a putative peroxismal membrane protein, Asp f9/16 (cell wall glucanase, Asp f11 (cyclophilin type peptidyl-prolyl isomerase and Asp f22 (enolase. Strong IFN-gamma responses were reproduced in most subjects tested over 6 month intervals.Products secreted after conidial germination into hyphae are differentially recognized by protective T cells in healthy, non-atopic individuals. Defining the specificity of the human T cell repertoire, and identifying factors that govern early responses may allow for development of novel diagnostics and therapeutics for both invasive and allergic Aspergillus diseases.

  1. Healthy human T-Cell Responses to Aspergillus fumigatus antigens.

    Science.gov (United States)

    Chaudhary, Neelkamal; Staab, Janet F; Marr, Kieren A

    2010-02-17

    Aspergillus fumigatus is associated with both invasive and allergic pulmonary diseases, in different hosts. The organism is inhaled as a spore, which, if not cleared from the airway, germinates into hyphal morphotypes that are responsible for tissue invasion and resultant inflammation. Hyphae secrete multiple products that function as antigens, evoking both a protective (T(H)1-T(H)17) and destructive allergic (T(H)2) immunity. How Aspergillus allergens (Asp f proteins) participate in the development of allergic sensitization is unknown. To determine whether Asp f proteins are strictly associated with T(H)2 responses, or represent soluble hyphal products recognized by healthy hosts, human T cell responses to crude and recombinant products were characterized by ELISPOT. While responses (number of spots producing IFN-gamma, IL-4 or IL-17) to crude hyphal antigen preparations were weak, responses to recombinant Asp f proteins were higher. Recombinant allergens stimulated cells to produce IFN-gamma more so than IL-4 or IL-17. Volunteers exhibited a diverse CD4+ and CD8+ T cell antigen recognition profile, with prominent CD4 T(H)1-responses to Asp f3 (a putative peroxismal membrane protein), Asp f9/16 (cell wall glucanase), Asp f11 (cyclophilin type peptidyl-prolyl isomerase) and Asp f22 (enolase). Strong IFN-gamma responses were reproduced in most subjects tested over 6 month intervals. Products secreted after conidial germination into hyphae are differentially recognized by protective T cells in healthy, non-atopic individuals. Defining the specificity of the human T cell repertoire, and identifying factors that govern early responses may allow for development of novel diagnostics and therapeutics for both invasive and allergic Aspergillus diseases.

  2. Enhancement of T cell responses as a result of synergy between lower doses of radiation and T cell stimulation.

    Science.gov (United States)

    Spary, Lisa K; Al-Taei, Saly; Salimu, Josephine; Cook, Alexander D; Ager, Ann; Watson, H Angharad; Clayton, Aled; Staffurth, John; Mason, Malcolm D; Tabi, Zsuzsanna

    2014-04-01

    As a side effect of cancer radiotherapy, immune cells receive varying doses of radiation. Whereas high doses of radiation (>10 Gy) can lead to lymphopenia, lower radiation doses (2-4 Gy) represent a valid treatment option in some hematological cancers, triggering clinically relevant immunological changes. Based on our earlier observations, we hypothesized that lower radiation doses have a direct positive effect on T cells. In this study, we show that 0.6-2.4 Gy radiation enhances proliferation and IFN-γ production of PBMC or purified T cells induced by stimulation via the TCR. Radiation with 1.2 Gy also lowered T cell activation threshold and broadened the Th1 cytokine profile. Although radiation alone did not activate T cells, when followed by TCR stimulation, ERK1/2 and Akt phosphorylation increased above that induced by stimulation alone. These changes were followed by an early increase in glucose uptake. Naive (CD45RA(+)) or memory (CD45RA(-)) T cell responses to stimulation were boosted at similar rates by radiation. Whereas increased Ag-specific cytotoxic activity of a CD8(+) T cell line manifested in a 4-h assay (10-20% increase), highly significant (5- to 10-fold) differences in cytokine production were detected in 6-d Ag-stimulation assays of PBMC, probably as a net outcome of death of nonstimulated and enhanced response of Ag-stimulated T cells. T cells from patients receiving pelvic radiation (2.2-2.75 Gy) also displayed increased cytokine production when stimulated in vitro. We report in this study enhanced T cell function induced by synergistic radiation treatment, with potential physiological significance in a wide range of T cell responses.

  3. T-cell activation and early gene response in dogs.

    Science.gov (United States)

    Mortlock, Sally-Anne; Wei, Jerry; Williamson, Peter

    2015-01-01

    T-cells play a crucial role in canine immunoregulation and defence against invading pathogens. Proliferation is fundamental to T-cell differentiation, homeostasis and immune response. Initiation of proliferation following receptor mediated stimuli requires a temporally programmed gene response that can be identified as immediate-early, mid- and late phases. The immediate-early response genes in T-cell activation engage the cell cycle machinery and promote subsequent gene activation events. Genes involved in this immediate-early response in dogs are yet to be identified. The present study was undertaken to characterise the early T-cell gene response in dogs to improve understanding of the genetic mechanisms regulating immune function. Gene expression profiles were characterised using canine gene expression microarrays and quantitative reverse transcription PCR (qRT-PCR), and paired samples from eleven dogs. Significant functional annotation clusters were identified following stimulation with phytohemagluttinin (PHA) (5μg/ml), including the Toll-like receptor signaling pathway and phosphorylation pathways. Using strict statistical criteria, 13 individual genes were found to be differentially expressed, nine of which have ontologies that relate to proliferation and cell cycle control. These included, prostaglandin-endoperoxide synthase 2 (PTGS2/COX2), early growth response 1 (EGR1), growth arrest and DNA damage-inducible gene (GADD45B), phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1), V-FOS FBJ murine osteosarcoma viral oncogene homolog (FOS), early growth response 2 (EGR2), hemogen (HEMGN), polo-like kinase 2 (PLK2) and polo-like kinase 3 (PLK3). Differential gene expression was re-examined using qRT-PCR, which confirmed that EGR1, EGR2, PMAIP1, PTGS2, FOS and GADD45B were significantly upregulated in stimulated cells and ALAS2 downregulated. PTGS2 and EGR1 showed the highest levels of response in these dogs. Both of these genes are involved in cell cycle

  4. T-cell activation and early gene response in dogs.

    Directory of Open Access Journals (Sweden)

    Sally-Anne Mortlock

    Full Text Available T-cells play a crucial role in canine immunoregulation and defence against invading pathogens. Proliferation is fundamental to T-cell differentiation, homeostasis and immune response. Initiation of proliferation following receptor mediated stimuli requires a temporally programmed gene response that can be identified as immediate-early, mid- and late phases. The immediate-early response genes in T-cell activation engage the cell cycle machinery and promote subsequent gene activation events. Genes involved in this immediate-early response in dogs are yet to be identified. The present study was undertaken to characterise the early T-cell gene response in dogs to improve understanding of the genetic mechanisms regulating immune function. Gene expression profiles were characterised using canine gene expression microarrays and quantitative reverse transcription PCR (qRT-PCR, and paired samples from eleven dogs. Significant functional annotation clusters were identified following stimulation with phytohemagluttinin (PHA (5μg/ml, including the Toll-like receptor signaling pathway and phosphorylation pathways. Using strict statistical criteria, 13 individual genes were found to be differentially expressed, nine of which have ontologies that relate to proliferation and cell cycle control. These included, prostaglandin-endoperoxide synthase 2 (PTGS2/COX2, early growth response 1 (EGR1, growth arrest and DNA damage-inducible gene (GADD45B, phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1, V-FOS FBJ murine osteosarcoma viral oncogene homolog (FOS, early growth response 2 (EGR2, hemogen (HEMGN, polo-like kinase 2 (PLK2 and polo-like kinase 3 (PLK3. Differential gene expression was re-examined using qRT-PCR, which confirmed that EGR1, EGR2, PMAIP1, PTGS2, FOS and GADD45B were significantly upregulated in stimulated cells and ALAS2 downregulated. PTGS2 and EGR1 showed the highest levels of response in these dogs. Both of these genes are involved in

  5. T cell response to N-formylated peptides in humans.

    Science.gov (United States)

    Ristori, G; Montesperelli, C; Fiorillo, M T; Battistini, L; Chersi, A; Sorrentino, R; Borsellino, G; Perna, A; Tramonti, D; Cannoni, S; Perrone, M P; Giubilei, F; Riccio, P; Salvetti, M; Buttinelli, C

    2001-09-01

    We present the first evidence of a T lymphocyte response to N-formylated peptides in humans. N-formylated peptide sequences from self (mitochondrial) and foreign (microbial) antigens were used to isolate antigen-specific T cell clones from healthy individuals, including a set of monozygotic twins. The observed response differed from that previously described in mouse (CD4(+) phenotype and MHC class II restriction in humans vs. CD8(+) phenotype and class I restriction in mice). These lymphocytes produce substantial amounts of IFN-gamma. They were isolated in only one of the monozygotic twins, which suggests that their expansion in the healthy immune repertoire is independent of the genetic background. Our result will help in assessing the relevance of N-formylated peptide-specific T cells in protection against infections within the human immune system.

  6. Induction of IL-10- and IFN-gamma-producing T-cell responses by autoreactive T-cells expressing human T-cell leukemia virus type I Tax.

    Science.gov (United States)

    Takatsuka, Natsuko; Hasegawa, Atsuhiko; Takamori, Ayako; Shimizu, Yukiko; Kato, Hirotomo; Ohashi, Takashi; Amagasa, Teruo; Masuda, Takao; Kannagi, Mari

    2009-09-01

    Human T-cell leukemia virus type I (HTLV-I) is associated with adult T-cell leukemia, HTLV-I-associated myelopathy/tropical spastic paraparesis and various autoimmune-like disorders. T-cell immune suppression is also associated with HTLV-I infection. Mechanisms of diverse immune dysregulation in HTLV-I infection are obscure. Here, we investigated a potential link between autoimmunity and immune suppression in HTLV-I infection. G14, an IL-2-dependent HTLV-I-negative CD4(+)CD8(+) T-cell line previously established from an HTLV-I-infected rat, constantly proliferated and produced IFN-gamma. IFN-gamma production by G14 cells was dependent on interactions between CD4 and MHC-II, suggesting that G14 cells recognized self-antigens presented by MHC-II on themselves. To examine immune response to G14 cells, we inoculated G14 cells into syngeneic naive rats. Interestingly, T-cells isolated from these rats vigorously proliferated when stimulated with G14-Tax cells that stably expressed HTLV-I Tax, but not with G14 cells. G14-Tax-mediated T-cell proliferation was abrogated by antibodies to CD80 and CD86 that were up-regulated in G14-Tax cells. T-cells propagated by repetitive G14-Tax cell stimulations in culture with IL-2 expressed CD4, CD25 and cytolytic T lymphocyte-associated antigen 4 (CTLA-4), produced abundant amounts of IL-10 and IFN-gamma in response to G14 cells and suppressed growth of G14 cells mainly through supernatant-mediated mechanisms. Similar IL-10- and IFN-gamma-producing CD4(+)CD25(+)CTLA-4(+) T-cells were predominantly induced in culture of splenocytes from HTLV-I-infected rats following stimulation with G14-Tax cells. These results implied that expression of Tax in the otherwise low immunogenic autoreactive T-cells induced IL-10- and IFN-gamma-producing T-cell responses with regulatory effects against the autoreactive cells. Our findings provide new insights into the complex immune conditions underlying HTLV-I-associated diseases.

  7. Baseline levels of influenza-specific CD4 memory T-cells affect T-cell responses to influenza vaccines.

    Science.gov (United States)

    He, Xiao-Song; Holmes, Tyson H; Sasaki, Sanae; Jaimes, Maria C; Kemble, George W; Dekker, Cornelia L; Arvin, Ann M; Greenberg, Harry B

    2008-07-02

    Factors affecting immune responses to influenza vaccines have not been studied systematically. We hypothesized that T-cell and antibody responses to the vaccines are functions of pre-existing host immunity against influenza antigens. During the 2004 and 2005 influenza seasons, we have collected data on cellular and humoral immune reactivity to influenza virus in blood samples collected before and after immunization with inactivated or live attenuated influenza vaccines in healthy children and adults. We first used cross-validated lasso regression on the 2004 dataset to identify a group of candidate baseline correlates with T-cell and antibody responses to vaccines, defined as fold-increase in influenza-specific T-cells and serum HAI titer after vaccination. The following baseline parameters were examined: percentages of influenza-reactive IFN-gamma(+) cells in T and NK cell subsets, percentages of influenza-specific memory B-cells, HAI titer, age, and type of vaccine. The candidate baseline correlates were then tested with the independent 2005 dataset. Baseline percentage of influenza-specific IFN-gamma(+) CD4 T-cells was identified as a significant correlate of CD4 and CD8 T-cell responses, with lower baseline levels associated with larger T-cell responses. Baseline HAI titer and vaccine type were identified as significant correlates for HAI response, with lower baseline levels and the inactivated vaccine associated with larger HAI responses. Previously we reported that baseline levels of CD56(dim) NK reactivity against influenza virus inversely correlated with the immediate T-cell response to vaccination, and that NK reactivity induced by influenza virus depended on IL-2 produced by influenza-specific memory T-cells. Taken together these results suggest a novel mechanism for the homeostasis of virus-specific T-cells, which involves interaction between memory helper T-cells, CD56(dim) NK and DC. These results demonstrate that assessment of baseline biomarkers may

  8. Baseline levels of influenza-specific CD4 memory T-cells affect T-cell responses to influenza vaccines.

    Directory of Open Access Journals (Sweden)

    Xiao-Song He

    Full Text Available BACKGROUND: Factors affecting immune responses to influenza vaccines have not been studied systematically. We hypothesized that T-cell and antibody responses to the vaccines are functions of pre-existing host immunity against influenza antigens. METHODOLOGY/PRINCIPAL FINDINGS: During the 2004 and 2005 influenza seasons, we have collected data on cellular and humoral immune reactivity to influenza virus in blood samples collected before and after immunization with inactivated or live attenuated influenza vaccines in healthy children and adults. We first used cross-validated lasso regression on the 2004 dataset to identify a group of candidate baseline correlates with T-cell and antibody responses to vaccines, defined as fold-increase in influenza-specific T-cells and serum HAI titer after vaccination. The following baseline parameters were examined: percentages of influenza-reactive IFN-gamma(+ cells in T and NK cell subsets, percentages of influenza-specific memory B-cells, HAI titer, age, and type of vaccine. The candidate baseline correlates were then tested with the independent 2005 dataset. Baseline percentage of influenza-specific IFN-gamma(+ CD4 T-cells was identified as a significant correlate of CD4 and CD8 T-cell responses, with lower baseline levels associated with larger T-cell responses. Baseline HAI titer and vaccine type were identified as significant correlates for HAI response, with lower baseline levels and the inactivated vaccine associated with larger HAI responses. Previously we reported that baseline levels of CD56(dim NK reactivity against influenza virus inversely correlated with the immediate T-cell response to vaccination, and that NK reactivity induced by influenza virus depended on IL-2 produced by influenza-specific memory T-cells. Taken together these results suggest a novel mechanism for the homeostasis of virus-specific T-cells, which involves interaction between memory helper T-cells, CD56(dim NK and DC

  9. Leukocytosis, muscle damage and increased lymphocyte proliferative response after an adventure sprint race

    Directory of Open Access Journals (Sweden)

    R. Tossige-Gomes

    2014-06-01

    Full Text Available The effect of an adventure sprint race (ASR on T-cell proliferation, leukocyte count and muscle damage was evaluated. Seven young male runners completed an ASR in the region of Serra do Espinhaço, Brazil. The race induced a strong leukocytosis (6.22±2.04×103 cells/mm3 before vs 14.81±3.53×103 cells/mm3 after the race, marked by a significant increase of neutrophils and monocytes (P<0.05, but not total lymphocytes, CD3+CD4+ or CD3+CD8+ cells. However, the T-cell proliferative response to mitogenic stimulation was increased (P=0.025 after the race, which contradicted our hypothesis that ASR, as a high-demand competition, would inhibit T-cell proliferation. A positive correlation (P=0.03, r=0.79 was observed between the proliferative response of lymphocytes after the race and the time to complete the race, suggesting that the proliferative response was dependent on exercise intensity. Muscle damage was evident after the race by increased serum levels of aspartate amino transferase (24.99±8.30 vs 50.61±15.76 U/L, P=0.003. The results suggest that humoral factors and substances released by damaged muscle may be responsible for lymphocyte activation, which may be involved in muscle recovery and repair.

  10. Anti-proliferative effects of T cells expressing a ligand-based chimeric antigen receptor against CD116 on CD34+ cells of juvenile myelomonocytic leukemia

    Directory of Open Access Journals (Sweden)

    Yozo Nakazawa

    2016-03-01

    Full Text Available Abstract Background Juvenile myelomonocytic leukemia (JMML is a fatal, myelodysplastic/myeloproliferative neoplasm of early childhood. Patients with JMML have mutually exclusive genetic abnormalities in granulocyte-macrophage colony-stimulating factor (GM-CSF receptor (GMR, CD116 signaling pathway. Allogeneic hematopoietic stem cell transplantation is currently the only curative treatment option for JMML; however, disease recurrence is a major cause of treatment failure. We investigated adoptive immunotherapy using GMR-targeted chimeric antigen receptor (CAR for JMML. Methods We constructed a novel CAR capable of binding to GMR via its ligand, GM-CSF, and generated piggyBac transposon-based GMR CAR-modified T cells from three healthy donors and two patients with JMML. We further evaluated the anti-proliferative potential of GMR CAR T cells on leukemic CD34+ cells from six patients with JMML (two NRAS mutations, three PTPN11 mutations, and one monosomy 7, and normal CD34+ cells. Results GMR CAR T cells from healthy donors suppressed the cytokine-dependent growth of MO7e cells, but not the growth of K562 and Daudi cells. Co-culture of healthy GMR CAR T cells with CD34+ cells of five patients with JMML at effector to target ratios of 1:1 and 1:4 for 2 days significantly decreased total colony growth, regardless of genetic abnormality. Furthermore, GMR CAR T cells from a non-transplanted patient and a transplanted patient inhibited the proliferation of respective JMML CD34+ cells at onset to a degree comparable to healthy GMR CAR T cells. Seven-day co-culture of GMR CAR T cells resulted in a marked suppression of JMML CD34+ cell proliferation, particularly CD34+CD38− cell proliferation stimulated with stem cell factor and thrombopoietin on AGM-S3 cells. Meanwhile, GMR CAR T cells exerted no effects on normal CD34+ cell colony growth. Conclusions Ligand-based GMR CAR T cells may have anti-proliferative effects on stem and progenitor cells in JMML.

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

    Science.gov (United States)

    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

  12. Relative contribution of "determinant selection" and "holes in the T-cell repertoire" to T-cell responses

    DEFF Research Database (Denmark)

    Schaeffer, E B; Sette, A; Johnson, D L

    1989-01-01

    -cell responses. Ia binding and Ia-restricted T-cell immunogenicity could be determined for a total of 54 peptide-MHC combinations. Only 30% of the 54 instances examined involved detectable Ia binding, but they represented almost all (12 of 13) of the immune responses found. However, binding to Ia......Using BALB/c and CBA/J mice, the I-region associated (Ia) binding capacity and T-cell immunogenicity of a panel of 14 overlapping peptides that span the entire sequence of the protein staphylococcal nuclease (Nase) was examined to evaluate major histocompatibility gene complex (MHC) control of T...... was not sufficient to ensure T-cell immunogenicity, since only 70% of the binding events were productive--i.e., were associated with an immune response. Thus, Ia molecules have the expected characteristics of a highly permissive capacity for antigen interaction that allows them to function as restriction elements...

  13. Characterization of the human T cell response to rye grass pollen allergens Lol p 1 and Lol p 5.

    Science.gov (United States)

    Burton, M D; Papalia, L; Eusebius, N P; O'Hehir, R E; Rolland, J M

    2002-12-01

    Knowledge of dominant T cell epitopes of major allergens recognized by allergic individuals is required to improve efficacy and safety of allergen immunotherapy. Rye grass pollen (RGP) is the most important source of seasonal aeroallergens in temperate climates and Lol p 1 and Lol p 5 are the two major IgE-reactive allergens. This study aimed to characterize the T cell response to these allergens using a large panel of RGP-sensitive individuals. Short-term RGP-specific T cell lines (TCL) were generated from 38 RGP-sensitive subjects and stimulated with Lol p 1 and/or Lol p 5 allergens and synthetic 20-mer peptides. Proliferative responses were determined by 3H-thymidine uptake and IL-5 and IFN-gamma in culture supernatants analysed by ELISA. Of 17 subjects tested for reactivity to both allergens 16 (94%) responded to Lol p 1 and/or Lol p 5, establishing these as major T cell-reactive allergens. Sites of T cell reactivity were spread throughout the allergen molecules but regions of high reactivity were found. For Lol p 1 these spanned residues 19-38, 109-128, 154-173, 190-209, and for Lol p 5 37-56, 100-119, 145-164, 154-173, 190-209, 217-236 and 226-245. IL-5 and IFN-gamma were produced by T cells cultured with proliferation-inducing peptides. T cell responses to RGP major allergens have been extensively characterized, providing fundamental information for developing T cell-targeted immunotherapy for RGP allergy.

  14. A response calculus for immobilized T cell receptor ligands

    DEFF Research Database (Denmark)

    Andersen, P S; Menné, C; Mariuzza, R A

    2001-01-01

    To address the molecular mechanism of T cell receptor (TCR) signaling, we have formulated a model for T cell activation, termed the 2D-affinity model, in which the density of TCR on the T cell surface, the density of ligand on the presenting surface, and their corresponding two-dimensional affini...

  15. Tracking the elusive cytotoxic T cell response in pigs

    DEFF Research Database (Denmark)

    Jungersen, Gregers; Nielsen, Morten; Overgaard, Nana Haahr

    Quantitative and qualitative assessment of antigen-specific cytotoxic T cell (CTL) responses in pigs is not a straightforward process. Through the years we have developed a series of reagents, tools and protocols to characterize peptide-specific CTL responses in pigs. The most common recombinant...... SLA heavy chains were produced and peptide binding motifs were determined by assays measuring the affinity and stability of the peptide-SLA complex (pSLA) interaction. These results have been used to train neural networks to predict the binding of any pSLA (http...... developed a protocol for intraperitoneal delivery of peptides formulated in poly(I:C)/MMG-decorated liposomes (CAF09) to investigate the influence of peptide dose on the generation of CTL vs. antibody responses. Finally, the induced CTL killing was assessed by an in vivo cytotoxicity assay, where purified...

  16. Immunotherapeutic strategies targeting Natural killer T cell responses in cancer

    Science.gov (United States)

    Shissler, Susannah C.; Bollino, Dominique R.; Tiper, Irina V.; Bates, Joshua; Derakhshandeh, Roshanak; Webb, Tonya J.

    2017-01-01

    Natural killer T (NKT) cells are a unique subset of lymphocytes that bridge the innate and adaptive immune system. NKT cells possess a classic αβ T-cell receptor (TCR) that is able to recognize self and foreign glycolipid antigens presented by the nonclassical class I major histocompatibility complex (MHC) molecule, CD1d. Type I NKT cells (referred to as invariant NKT cells) express a semi-invariant Vα14Jα18 TCR in mice and Vα24Jα18 TCR in humans. Type II NKT cells are CD1d-restricted T cells that express a more diverse set of TCR α chains. The two types of NKT cells often exert opposing effects especially in tumor immunity, where Type II cells generally suppress tumor immunity while Type I NKT cells can enhance antitumor immune responses. In this review, we focus on the role of NKT cells in cancer. We discuss their effector and suppressive functions, as well as describe preclinical and clinical studies utilizing therapeutic strategies focused on harnessing their potent anti-tumor effector functions, and conclude with a discussion on potential next steps for the utilization of NKT cell targeted therapies for the treatment of cancer. PMID:27393665

  17. Transcriptional regulation during CD8 T-cell immune responses.

    Science.gov (United States)

    Munitic, Ivana; Evaristo, César; Sung, Hsueh Cheng; Rocha, Benedita

    2010-01-01

    Naïve CD8 T cells differentiate in response to antigen stimulation. They acquire the capacity to express multiple effector molecules and mediate effector functions that contribute to infection control. Once antigen loads are reduced they revert progressively to a less activated status and eventually reach a steady-state referred to as "memory" that is very different from that of naive cells. Indeed, these "memory" cells are "ready-to-go" populations that acquired the capacity to respond more efficiently to antigen stimulation. They modify their cell cycle machinery in order to divide faster; they likely improve DNA repair and other cell survival mechanisms in order to survive during division and thus to generate much larger clones of effector cells; finally, they also mediate effector functions much faster. These modifications are the consequence of changes in the expression of multiple genes, i.e., on the utilization of a new transcription program.

  18. Endogenous Tim-1 (Kim-1) promotes T-cell responses and cell-mediated injury in experimental crescentic glomerulonephritis.

    Science.gov (United States)

    Nozaki, Yuji; Nikolic-Paterson, David J; Snelgrove, Sarah L; Akiba, Hisaya; Yagita, Hideo; Holdsworth, Stephen R; Kitching, A Richard

    2012-05-01

    The T-cell immunoglobulin mucin 1 (Tim-1) modulates CD4(+) T-cell responses and is also expressed by damaged proximal tubules in the kidney where it is known as kidney injury molecule-1 (Kim-1). We sought to define the role of endogenous Tim-1 in experimental T-cell-mediated glomerulonephritis induced by sheep anti-mouse glomerular basement membrane globulin acting as a planted foreign antigen. Tim-1 is expressed by infiltrating activated CD4(+) cells in this model, and we studied the effects of an inhibitory anti-Tim-1 antibody (RMT1-10) on immune responses and glomerular disease. Crescentic glomerulonephritis, proliferative injury, and leukocyte accumulation were attenuated following treatment with anti-Tim-1 antibodies, but interstitial foxp3(+) cell accumulation and interleukin-10 mRNA were increased. T-cell proliferation and apoptosis decreased in the immune system along with a selective reduction in Th1 and Th17 cellular responses both in the immune system and within the kidney. The urinary excretion and renal expression of Kim-1 was reduced by anti-Tim-1 antibodies reflecting diminished interstitial injury. The effects of anti-Tim-1 antibodies were not apparent in the early phase of renal injury, when the immune response to sheep globulin was developing. Thus, endogenous Tim-1 promotes Th1 and Th17 nephritogenic immune responses and its neutralization reduces renal injury while limiting inflammation in cell-mediated glomerulonephritis.

  19. Modulation of immune responses to Mycobacterium bovis in cattle depleted of WC1(+) gamma delta T cells.

    Science.gov (United States)

    Kennedy, Hilary E; Welsh, Michael D; Bryson, David G; Cassidy, Joseph P; Forster, Fiona I; Howard, Christopher J; Collins, Robert A; Pollock, John M

    2002-03-01

    It is accepted that cell-mediated immune responses predominate in mycobacterial infections. Many studies have shown that CD4(+) T cells produce Th1 cytokines, such as gamma interferon (IFN-gamma), in response to mycobacterial antigens and that the cytolytic activity of CD8(+) cells toward infected macrophages is important. However, the extent and manner in which gamma delta T cells participate in this response remain unclear. In ruminants, gamma delta T cells comprise a major proportion of the peripheral blood mononuclear cell population. We have previously shown that WC1(+) gamma delta T cells are involved early in Mycobacterium bovis infection of cattle, but their specific functions are not well understood. Here we describe an in vivo model of bovine tuberculosis in which the WC1(+) gamma delta T cells were depleted from the peripheral circulation and respiratory tract, by infusion of WC1(+)-specific monoclonal antibody, prior to infection. While no effects on disease pathology were observed in this experiment, results indicate that WC1(+) gamma delta T cells, which become significantly activated (CD25(+)) in the circulation of control calves from 21 days postinfection, may play a role in modulating the developing immune response to M. bovis. WC1(+)-depleted animals exhibited decreased antigen-specific lymphocyte proliferative response, an increased antigen-specific production of interleukin-4, and a lack of specific immunoglobulin G2 antibody. This suggests that WC1(+) gamma delta TCR(+) cells contribute, either directly or indirectly, toward the Th1 bias of the immune response in bovine tuberculosis--a hypothesis supported by the decreased innate production of IFN-gamma, which was observed in WC1(+)-depleted calves.

  20. Acrolein in cigarette smoke inhibits T-cell responses.

    Science.gov (United States)

    Lambert, Cherie; McCue, Jesica; Portas, Mary; Ouyang, Yanli; Li, JiMei; Rosano, Thomas G; Lazis, Alexander; Freed, Brian M

    2005-10-01

    Cigarette smoking inhibits T-cell responses in the lungs, but the immunosuppressive compounds have not been fully identified. Cigarette smoke extracts inhibit IL-2, IFN-gamma, and TNF-alpha production in stimulated lymphocytes obtained from peripheral blood, even when the extracts were diluted 100-fold to 1000-fold. The objective of these studies was to identify the immunosuppressive compounds found in cigarette smoke. Gas chromatography/mass spectroscopy and HPLC were used to identify and quantitate volatile compounds found in cigarette smoke extracts. Bioactivity was measured by viability and production of cytokine mRNA and protein levels in treated human lymphocytes. The vapor phase of the cigarette smoke extract inhibited cytokine production, indicating that the immunosuppressive compounds were volatile. Among the volatile compounds identified in cigarette smoke extracts, only the alpha,beta-unsaturated aldehydes, acrolein (inhibitory concentration of 50% [IC50] = 3 micromol/L) and crotonaldehyde (IC50 = 6 micromol/L), exhibited significant inhibition of cytokine production. Although the levels of aldehydes varied 10-fold between high-tar (Camel) and ultralow-tar (Carlton) extracts, even ultralow-tar cigarettes produced sufficient levels of acrolein (34 micromol/L) to suppress cytokine production by >95%. We determined that the cigarette smoke extract inhibited transcription of cytokine genes. The inhibitory effects of acrolein could be blocked with the thiol compound N-acetylcysteine. The vapor phase from cigarette smoke extracts potently suppresses cytokine production. The compound responsible for this inhibition appears to be acrolein.

  1. Antitumor Responses of Invariant Natural Killer T Cells

    Directory of Open Access Journals (Sweden)

    Jennie B. Altman

    2015-01-01

    Full Text Available Natural killer T (NKT cells are innate-like lymphocytes that were first described in the late 1980s. Since their initial description, numerous studies have collectively shed light on their development and effector function. These studies have highlighted the unique requirements for the activation of these lymphocytes and the functional responses that distinguish these cells from other effector lymphocyte populations such as conventional T cells and NK cells. This body of literature suggests that NKT cells play diverse nonredundant roles in a number of disease processes, including the initiation and propagation of airway hyperreactivity, protection against a variety of pathogens, development of autoimmunity, and mediation of allograft responses. In this review, however, we focus on the role of a specific lineage of NKT cells in antitumor immunity. Specifically, we describe the development of invariant NKT (iNKT cells and the factors that are critical for their acquisition of effector function. Next, we delineate the mechanisms by which iNKT cells influence and modulate the activity of other immune cells to directly or indirectly affect tumor growth. Finally, we review the successes and failures of clinical trials employing iNKT cell-based immunotherapies and explore the future prospects for the use of such strategies.

  2. Immunoregulatory mechanisms in Chagas disease: modulation of apoptosis in T-cell mediated immune responses.

    Science.gov (United States)

    Chaves, Ana Thereza; de Assis Silva Gomes Estanislau, Juliana; Fiuza, Jacqueline Araújo; Carvalho, Andréa Teixeira; Ferreira, Karine Silvestre; Fares, Rafaelle Christine Gomes; Guimarães, Pedro Henrique Gazzinelli; de Souza Fagundes, Elaine Maria; Morato, Maria José; Fujiwara, Ricardo Toshio; da Costa Rocha, Manoel Otávio; Correa-Oliveira, Rodrigo

    2016-04-30

    Chronic Chagas disease presents different clinical manifestations ranging from asymptomatic (namely indeterminate) to severe cardiac and/or digestive. Previous results have shown that the immune response plays an important role, although no all mechanisms are understood. Immunoregulatory mechanisms such as apoptosis are important for the control of Chagas disease, possibly affecting the morbidity in chronic clinical forms. Apoptosis has been suggested to be an important mechanism of cellular response during T. cruzi infection. We aimed to further understand the putative role of apoptosis in Chagas disease and its relation to the clinical forms of the disease. Apoptosis of lymphocytes, under antigenic stimuli (soluble T. cruzi antigens - TcAg) where compared to that of non-stimulated cells. Apoptosis was evaluated using the expression of annexin and caspase 3(+) by T cells and the percentage of cells positive evaluated by flow cytometry. In addition activation and T cell markers were used for the identification of TCD4(+) and TCD8(+) subpopulations. The presence of intracellular and plasma cytokines were also evaluated. Analysis of the activation status of the peripheral blood cells showed that patients with Chagas disease presented higher levels of activation determined by the expression of activation markers, after TcAg stimulation. PCR array were used to evaluate the contribution of this mechanism in specific cell populations from patients with different clinical forms of human Chagas disease. Our results showed a reduced proliferative response associated a high expression of T CD4(+)CD62L(-) cells in CARD patients when compared with IND group and NI individuals. We also observed that both groups of patients presented a significant increase of CD4(+) and CD8(+) T cell subsets in undergoing apoptosis after in vitro stimulation with T. cruzi antigens. In CARD patients, both CD4(+) and CD8(+) T cells expressing TNF-α were highly susceptible to undergo apoptosis

  3. Successful generation of primary virus-specific and anti-tumor T-cell responses from the naive donor T-cell repertoire is determined by the balance between antigen-specific precursor T cells and regulatory T cells.

    NARCIS (Netherlands)

    Jedema, I.; Meent, M. van de; Pots, J.M.; Kester, M.G.; Beek, M.T. van der; Falkenburg, J.H.F.

    2011-01-01

    BACKGROUND: One of the major challenges in allogeneic stem cell transplantation is to find a balance between the harmful induction of graft-versus-host disease and the beneficial graft-versus-leukemia and pathogen-specific immune responses. Adoptive transfer of in-vitro generated donor T cells with

  4. Proliferative responses of blood mononuclear cells (BMNC) in a cohort of elderly humans: role of lymphocyte phenotype and cytokine production

    DEFF Research Database (Denmark)

    Bruunsgaard, H.; Pedersen, Agnes Nadelmann; Schroll, M.

    2000-01-01

    Age-related impaired T cell function is associated with increased mortality risk. The purpose of the present study was therefore to identify factors associated with the age-related decreased phytohaemagglutinin (PHA)-induced proliferative response of lymphocytes in a cohort of 174 81-year-old hum......- and IL-2-producing cells were of importance in both elderly and young subjects. Accordingly, a minimum of true naive CD4(+) cells was required for a normal proliferative response to PHA, perhaps by providing sufficient IL-2 which is critical for growth of naive as well as memory cells....

  5. An anti-CD45RO/RB monoclonal antibody modulates T cell responses via induction of apoptosis and generation of regulatory T cells

    OpenAIRE

    Gregori, Silvia; Mangia, Patrizia; Bacchetta, Rosa; Tresoldi, Eleonora; Kolbinger, Frank; Traversari, Catia; Carballido, Josè M.; de Vries, Jan E.; Korthäuer, Ulf; Roncarolo, Maria-Grazia

    2005-01-01

    The effects of a chimeric monoclonal antibody (chA6 mAb) that recognizes both the RO and RB isoforms of the transmembrane protein tyrosine phosphatase CD45 on human T cells were investigated. Chimeric A6 (chA6) mAb potently inhibited antigen-specific and polyclonal T cell responses. ChA6 mAb induced activation-independent apoptosis in CD4+CD45RO/RBhigh T cells but not in CD8+ T cells. In addition, CD4+ T cell lines specific for tetanus toxoid (TT) generated in the presence of chA6 mAb were an...

  6. Human Naive and Memory T Cells Display Opposite Migratory Responses to Sphingosine-1 Phosphate.

    Science.gov (United States)

    Drouillard, Annabelle; Neyra, Antoinette; Mathieu, Anne-Laure; Marçais, Antoine; Wencker, Mélanie; Marvel, Jacqueline; Belot, Alexandre; Walzer, Thierry

    2018-01-15

    The role of sphingosine-1 phosphate (S1P) in leukocyte trafficking has been well deciphered in mice but remains largely unaddressed in humans. In this study, we assessed the ex vivo response to S1P of primary human T cell subsets. We found that tonsil but not blood leukocytes were responsive to S1P gradients, suggesting that T cell responsiveness is regulated during their recirculation in vivo. Tonsil naive T cells were readily chemoattracted by S1P in an FTY720-sensitive, S1PR1-dependent manner. Surprisingly, S1P had the opposite effect on effector memory T cells, resident memory T cells, and recently activated T cells, inhibiting their spontaneous or chemokine-induced migration. This inhibition was also more pronounced for CD4 T cells than for CD8 T cell subsets, and was dependent on S1PR2, as shown using the S1PR2 antagonist JTE-013. S1PR1 was progressively downregulated during T cell differentiation whereas S1PR2 expression remained stable. Our results suggest that the ratio between S1PR1 and S1PR2 governs the migratory behavior of T cell subsets. They also challenge previous models of the role of S1P in lymphocyte recirculation and suggest that S1P promotes retention of memory T cell subsets in secondary lymphoid organs, via S1PR2. Copyright © 2018 by The American Association of Immunologists, Inc.

  7. DX5+ CD4+ T cells modulate CD4+ T-cell response via inhibition of IL-12 production by DCs.

    Science.gov (United States)

    el Bannoudi, Hanane; Han, Wanda G H; Stoop, Jeroen N; Louis-Plence, Pascale; Huizinga, Tom W J; Toes, René E M

    2013-02-01

    DX5(+) CD4(+) T cells have been shown to dampen collagen-induced arthritis and delayed-type hypersensitivity reactions in mice. These cells are also potent modulators of T-helper cell responses through direct effects on CD4(+) T cells in an IL-4 dependent manner. To further characterize this T-cell population, we studied their effect on DCs and the potential consequences on T-cell activation. Here, we show that mouse DX5(+) CD4(+) T cells modulate DCs by robustly inhibiting IL-12 production. This modulation is IL-10 dependent and does not require cell contact. Furthermore, DX5(+) CD4(+) T cells modulate the surface phenotype of LPS-matured DCs. DCs modulated by DX5(+) CD4(+) T-cell supernatant express high levels of the co-inhibitor molecules PDL-1 and PDL-2. OVA-specific CD4(+) T cells primed with DCs exposed to DX5(+) CD4(+) T-cell supernatant produce less IFN-γ than CD4(+) T cells primed by DCs exposed to either medium or DX5(-) CD4(+) T-cell supernatant. The addition of IL-12 to the co-culture with DX5(+) DCs restores IFN-γ production. When IL-10 present in the DX5(+) CD4(+) T-cell supernatant is blocked, DCs re-establish their ability to produce IL-12 and to efficiently prime CD4(+) T cells. These data show that DX5(+) CD4(+) T cells can indirectly affect the outcome of the T-cell response by inducing DCs that have poor Th1 stimulatory function. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The Timing of Stimulation and IL-2 Signaling Regulate Secondary CD8 T Cell Responses

    Science.gov (United States)

    Khan, Shaniya H.; Martin, Matthew D.; Starbeck-Miller, Gabriel R.; Xue, Hai-Hui; Harty, John T.; Badovinac, Vladimir P.

    2015-01-01

    Abstract Memory CD8 T cells provide protection to immune hosts by eliminating pathogen-infected cells during re-infection. While parameters influencing the generation of primary (1°) CD8 T cells are well established, the factors controlling the development of secondary (2°) CD8 T cell responses remain largely unknown. Here, we address the mechanisms involved in the generation and development of 2° memory (M) CD8 T cells. We observed that the time at which 1° M CD8 T cells enter into immune response impacts their fate and differentiation into 2° M CD8 T cells. Late-entry of 1° M CD8 T cells into an immune response (relative to the onset of infection) not only facilitated the expression of transcription factors associated with memory formation in 2° effector CD8 T cells, but also influenced the ability of 2° M CD8 T cells to localize within the lymph nodes, produce IL-2, and undergo Ag-driven proliferation. The timing of stimulation of 1° M CD8 T cells also impacted the duration of expression of the high-affinity IL-2 receptor (CD25) on 2° effector CD8 T cells and their sensitivity to IL-2 signaling. Importantly, by blocking or enhancing IL-2 signaling in developing 2° CD8 T cells, we provide direct evidence for the role of IL-2 in controlling the differentiation of Ag-driven 2° CD8 T cell responses. Thus, our data suggest that the process of 1° M to 2° M CD8 T cell differentiation is not fixed and can be manipulated, a notion with relevance for the design of future prime-boost vaccination approaches. PMID:26431533

  9. Lowering T Cell Activation Thresholds and Deregulating Homeostasis to Facilitate Immunotherapeutic Responses to Treat Prostate Cancer

    National Research Council Canada - National Science Library

    Kwon, Eugene D

    2006-01-01

    ... to develop immune-based therapies for prostate cancer Hence, relatively straightforward manipulations that induce specific T cell responses against prostate tumors or epithelial tissues, especially...

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

    DEFF Research Database (Denmark)

    Norbeck, Oscar; Isa, Adiba; Pöhlmann, Christoph

    2005-01-01

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

  11. T-cell immunosenescence and inflammatory response in atomic bomb survivors.

    Science.gov (United States)

    Kusunoki, Yoichiro; Yamaoka, Mika; Kubo, Yoshiko; Hayashi, Tomonori; Kasagi, Fumiyoshi; Douple, Evan B; Nakachi, Kei

    2010-12-01

    In this paper we summarize the long-term effects of A-bomb radiation on the T-cell system and discuss the possible involvement of attenuated T-cell immunity in the disease development observed in A-bomb survivors. Our previous observations on such effects include impaired mitogen-dependent proliferation and IL-2 production, decreases in naive T-cell populations, and increased proportions of anergic and functionally weak memory CD4 T-cell subsets. In addition, we recently found a radiation dose-dependent increase in the percentages of CD25(+)/CD127(-) regulatory T cells in the CD4 T-cell population of the survivors. All these effects of radiation on T-cell immunity resemble effects of aging on the immune system, suggesting that ionizing radiation might direct the T-cell system toward a compromised phenotype and thereby might contribute to an enhanced immunosenescence. Furthermore, there are inverse, significant associations between plasma levels of inflammatory cytokines and the relative number of naïve CD4 T cells, also suggesting that the elevated levels of inflammatory markers found in A-bomb survivors can be ascribed in part to T-cell immunosenescence. We suggest that radiation-induced T-cell immunosenescence may result in activation of inflammatory responses and may be partly involved in the development of aging-associated and inflammation-related diseases frequently observed in A-bomb survivors.

  12. CD8+T Cell Immune Response in Immunocompetent Mice during Zika Virus Infection.

    Science.gov (United States)

    Huang, Huarong; Li, Shihua; Zhang, Yongli; Han, Xiaojuan; Jia, Baoqian; Liu, Hongtao; Liu, Dandan; Tan, Shuguang; Wang, Qihui; Bi, Yuhai; Liu, William J; Hou, Baidong; Gao, George Fu; Zhang, Fuping

    2017-11-15

    Zika virus (ZIKV) infection causees neurologic complications, including Guillain-Barré syndrome in adults and central nervous system (CNS) abnormalities in fetuses. We investigated the immune response, especially the CD8 + T cell response in C57BL/6 (B6) wild-type (WT) mice, during ZIKV infection. We found that a robust CD8 + T cell response was elicited, major histocompatibility complex class I-restricted CD8 + T cell epitopes were identified, a tetramer that recognizes ZIKV-specific CD8 + T cells was developed, and virus-specific memory CD8 + T cells were generated in these mice. The CD8 + T cells from these infected mice were functional, as evidenced by the fact that the adoptive transfer of ZIKV-specific CD8 + T cells could prevent ZIKV infection in the CNS and was cross protective against dengue virus infection. Our findings provide comprehensive insight into immune responses against ZIKV and further demonstrate that WT mice could be a natural and easy-access model for evaluating immune responses to ZIKV infection. IMPORTANCE ZIKV infection has severe clinical consequences, including Guillain-Barré syndrome in adults, microcephaly, and congenital malformations in fetuses and newborn infants. Therefore, study of the immune response, especially the adaptive immune response to ZIKV infection, is important for understanding diseases caused by ZIKV infection. Here, we characterized the CD8 + T cell immune response to ZIKV in a comprehensive manner and identified ZIKV epitopes. Using the identified immunodominant epitopes, we developed a tetramer that recognizes ZIKV-specific CD8 + T cells in vivo , which simplified the detection and evaluation of ZIKV-specific immune responses. In addition, the finding that tetramer-positive memory CD8 + T cell responses were generated and that CD8 + T cells can traffic to a ZIKV-infected brain greatly enhances our understanding of ZIKV infection and provides important insights for ZIKV vaccine design. Copyright © 2017 American

  13. CD4+ T-cell priming as biomarker to study immune response to preventive vaccines

    Directory of Open Access Journals (Sweden)

    Annalisa eCiabattini

    2013-12-01

    Full Text Available T-cell priming is a critical event in the initiation of the immune response to vaccination since it deeply influences both the magnitude and the quality of the immune response induced. CD4+ T-cell priming, required for the induction of high-affinity antibodies and immune memory, represents a key target for improving and modulating vaccine immunogenicity. A major challenge in the study of in vivo T-cell priming is due to the low frequency of antigen-specific T cells. This review discusses the current knowledge on antigen-specific CD4+ T-cell priming in the context of vaccination, as well as the most advanced tools for the characterization of the in vivo T-cell priming and the opportunities offered by the application of systems biology.

  14. CD4(+) T Cell Priming as Biomarker to Study Immune Response to Preventive Vaccines.

    Science.gov (United States)

    Ciabattini, Annalisa; Pettini, Elena; Medaglini, Donata

    2013-12-04

    T cell priming is a critical event in the initiation of the immune response to vaccination since it deeply influences both the magnitude and the quality of the immune response induced. CD4(+) T cell priming, required for the induction of high-affinity antibodies and immune memory, represents a key target for improving and modulating vaccine immunogenicity. A major challenge in the study of in vivo T cell priming is due to the low frequency of antigen-specific T cells. This review discusses the current knowledge on antigen-specific CD4(+) T cell priming in the context of vaccination, as well as the most advanced tools for the characterization of the in vivo T cell priming and the opportunities offered by the application of systems biology.

  15. CD4+ T Cell Priming as Biomarker to Study Immune Response to Preventive Vaccines

    Science.gov (United States)

    Ciabattini, Annalisa; Pettini, Elena; Medaglini, Donata

    2013-01-01

    T cell priming is a critical event in the initiation of the immune response to vaccination since it deeply influences both the magnitude and the quality of the immune response induced. CD4+ T cell priming, required for the induction of high-affinity antibodies and immune memory, represents a key target for improving and modulating vaccine immunogenicity. A major challenge in the study of in vivo T cell priming is due to the low frequency of antigen-specific T cells. This review discusses the current knowledge on antigen-specific CD4+ T cell priming in the context of vaccination, as well as the most advanced tools for the characterization of the in vivo T cell priming and the opportunities offered by the application of systems biology. PMID:24363656

  16. T cell responses in senior patients with community-acquired pneumonia related to disease severity.

    Science.gov (United States)

    Bian, Lu-Qin; Bi, Ying; Zhou, Shao-Wei; Chen, Zi-Dan; Wen, Jun; Shi, Jin; Mao, Ling; Wang, Ling

    2017-12-01

    Senior individuals older than 65 years of age are at a disproportionally higher risk of developing pneumonia. Impaired capacity to defend against airway infections may be one of the reasons. It is generally believed that weaker regulatory T cell responses may be beneficial to host defense against pathogens. In senior patients with community-acquired bacterial pneumonia, we investigated the frequencies and functions of regulatory T cells. Interestingly, we found that compared to age- and sex-matched healthy controls, senior pneumonia patients presented lower frequencies of Foxp3-expressing and Helios-expressing CD4 + T cells. The quantity of Foxp3 and Helios being expressed, measured by their mRNA transcription levels, was also lower in CD4 + T cells from pneumonia patients. Furthermore, following TCR and TGF-β stimulation, pneumonia patients presented impaired capacity to upregulate Foxp3 and Helios. Functional analyses revealed that CD4 + T cells from pneumonia patients secreted lower amounts of IL-10 and TGF-β, two cytokines critical to regulatory T cell-mediated suppression. Also, the expression of granzyme B and perforin, which were cytolytic molecules potentially utilized by regulatory T cells to mediate the elimination of antigen-presenting cells and effector T cells, were reduced in CD4 + CD25 + T cells from senior pneumonia patients. In addition, the CD4 + CD25 + T cells from senior pneumonia patients presented reduced capacity to suppress effector CD4 + and CD8 + T cell proliferation. Moreover, the value of pneumonia severity index was inversely correlated with several parameters of regulatory T cell function. Together, our results demonstrated that senior pneumonia patients presented a counterintuitive impairment in regulatory T cell responses that was associated with worse prognosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Downregulation of inhibitory SRC Homology 2 Domain-containing Phosphatase-1 (SHP-1) leads to recovery of T cell responses in elderly

    Science.gov (United States)

    2014-01-01

    Background Immune responses are generally impaired in aged mammals. T cells have been extensively studied in this context due to the initial discovery of their reduced proliferative capacity with aging. The decreased responses involve altered signaling events associated with the early steps of T cell activation. The underlying causes of these changes are not fully understood but point to alterations in assembly of the machinery for T cell activation. Here, we have tested the hypothesis that the T cell pool in elderly subjects displayed reduced functional capacities due to altered negative feedback mechanisms that participate in the regulation of the early steps of T cell activation. Such conditions tip the immune balance in favor of altered T cell activation and a related decreased response in aging. Results We present evidence that the tyrosine phosphatase SHP-1, a key regulator of T cell signal transduction machinery is, at least in part, responsible for the impaired T cell activation in aging. We used tyrosine-specific mAbs and Western blot analysis to show that a deregulation of the Csk/PAG loop in activated T cells from elderly individuals favored the inactive form of tyrosine-phosphorylated Lck (Y505). Confocal microscopy analysis revealed that the dynamic movements of these regulatory proteins in lipid raft microdomains was altered in T cells of aged individuals. Enzymic assays showed that SHP-1 activity was upregulated in T cells of aged donors, in contrast to young subjects. Pharmacological inhibition of SHP-1 resulted in recovery of TCR/CD28-dependent lymphocyte proliferation and IL-2 production of aged individuals to levels approaching those of young donors. Significant differences in the active (Y394) and inactive (Y505) phosphorylation sites of Lck in response to T cell activation were observed in elderly donors as compared to young subjects, independently of CD45 isoform expression. Conclusions Our data suggest that the role of SHP-1 in T cell

  18. Time and Antigen-Stimulation History Influence Memory CD8 T Cell Bystander Responses.

    Science.gov (United States)

    Martin, Matthew D; Shan, Qiang; Xue, Hai-Hui; Badovinac, Vladimir P

    2017-01-01

    Memory CD8 T cells can be activated and induced to produce cytokines and increase stores of cytolytic proteins not only in response to cognate antigen (Ag) but also in response to inflammatory cytokines (bystander responses). Importantly, bystander memory CD8 T cell functions have been shown to be dependent upon memory CD8 T cell fitness, since exhausted CD8 T cells have diminished capacity to respond to inflammatory cues. While it is known that memory CD8 T cell functional abilities, including ability to produce cytokines in response to cognate Ag, change with time after initial Ag encounter and upon multiple Ag stimulations (e.g., primary vs. tertiary CD8 T cell responses), it is unknown if bystander memory CD8 T cell responses are influenced by time or by Ag-exposure history. Here, we examined time and Ag-stimulation history-dependent alterations in virus-specific memory CD8 T cell bystander functions in response to inflammatory cytokines and unrelated bacterial infection. We found that expression of cytokine receptors and ability to produce IFN-γ following heterologous infection or incubation with inflammatory cytokines decreases with time following initial Ag encounter and increases with additional Ag encounters, suggesting that the ability to sense inflammation and respond with bystander cytokine production is dependent on age and Ag-stimulation history of memory CD8 T cells. These data shed further light on the regulation of memory CD8 T cell effector functions and have important implications for the development of vaccines designed to elicit protective memory CD8 T cells.

  19. Plasticity of gamma delta T cells: impact on the anti-tumor response

    Directory of Open Access Journals (Sweden)

    Virginie eLafont

    2014-12-01

    Full Text Available The tumor immune microenvironment contributes to tumor initiation, progression and response to therapy. Among the immune cell subsets that play a role in the tumor microenvironment, innate-like T cells that express T cell receptors composed of gamma and delta chains (gamma delta T cells are of particular interest. gamma delta T cells can contribute to the immune response against many tumor types (lymphoma, myeloma, melanoma, breast, colon, lung, ovary and prostate cancer directly through their cytotoxic activity and indirectly by stimulating or regulating the biological functions of other cell types required for the initiation and establishment of the anti-tumor immune response, such as dendritic cells and cytotoxic CD8+ T cells. However, the notion that tumor-infiltrating gamma delta T cells are a good prognostic marker in cancer was recently challenged by studies showing that the presence of these cells in the tumor microenvironment was associated with poor prognosis in both breast and colon cancer. These findings suggest that gamma delta T cells may also display pro-tumor activities. Indeed, breast tumor-infiltrating gamma deltaT cells could exert an immunosuppressive activity by negatively regulating DC maturation. Furthermore, recent studies demonstrated that signals from the microenvironment, particularly cytokines, can confer some plasticity to gamma delta T cells and promote their differentiation into gamma delta T cells with regulatory functions. This review focuses on the current knowledge on the functional plasticity of gamma delta T cells and its effect on their anti-tumor activities. It also discusses the putative mechanisms underlying gamma delta T cell expansion, differentiation and recruitment in the tumor microenvironment.

  20. Parallel detection of antigen-specific T-cell responses by multidimensional encoding of MHC multimers

    DEFF Research Database (Denmark)

    Hadrup, Sine Reker; Bakker, Arnold H; Shu, Chengyi J

    2009-01-01

    The use of fluorescently labeled major histocompatibility complex multimers has become an essential technique for analyzing disease- and therapy-induced T-cell immunity. Whereas classical major histocompatibility complex multimer analyses are well-suited for the detection of immune responses...... to a few epitopes, limitations on human-subject sample size preclude a comprehensive analysis of T-cell immunity. To address this issue, we developed a combinatorial encoding strategy that allows the parallel detection of a multitude of different T-cell populations in a single sample. Detection of T cells...

  1. Mobilization of regulatory T cells in response to carotid injury does not influence subsequent neointima formation.

    Directory of Open Access Journals (Sweden)

    Amit Saxena

    Full Text Available AIM: T cells have been attributed an important role in modulating repair responses following vascular injury. The aim of this study was to investigate the role of different T cell subsets in this context. METHODS AND RESULTS: A non-obstructive collar was introduced to inflict carotid artery injury in mice and subsequent activation of immune cells in draining lymph nodes and spleen were studied by flow cytometry. Carotid artery injury of wild type mice was associated with mobilization of both Th1 type CD4(+IFNγ(+ and regulatory CD4(+CD25(+FoxP3(+ T cells in draining lymph nodes. Studies using FoxP3-green fluorescent protein (GFP transgenic C57/Bl6 mice demonstrated scattered presence of regulatory T cells in the adventitial tissue of injured arteries as well as a massive emigration of regulatory T cells from the spleen in response to carotid injury. However, deletion of antigen presentation to CD4+ T cells (H2(0 mice, as well as deletion of regulatory T cells (through treatment with blocking anti-CD25 antibodies, did not affect neointima formation. Also deletion of antigen presentation to CD8(+ T cells (Tap1(0 mice was without effect on carotid collar-induced neointima formation. CONCLUSION: The results demonstrate that carotid artery injury is associated with mobilization of regulatory T cells. Depletion of regulatory T cells does not, however, influence the subsequent repair processes leading to the formation of a neointima. The results also demonstrate that lack of CD8(+ T cells does not influence neointima formation in presence of functional CD4(+ T cells and B cells.

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

    DEFF Research Database (Denmark)

    Kasprowicz, V; Isa, Adiba; Jeffery, K

    2006-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-05

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

  4. Induction and analysis of antigen-specific T cell responses in melanoma patients and animal models

    NARCIS (Netherlands)

    Bins, Adriaan Dirk

    2007-01-01

    This thesis introduces a novel T cell vaccination method that uses a tattoo machine to inject DNA in the skin of the vaccinee. In comparison to other experimental vaccination methods DNA tattooing is very strong: besides small laboratory animals also large animals mount strong T cell responses upon

  5. Human CD8(+) T-cell differentiation in response to viruses

    NARCIS (Netherlands)

    van Lier, René A. W.; ten Berge, Ineke J. M.; Gamadia, Laila E.

    2003-01-01

    CD8(+) T cells are essential in the defence against viruses. Recently, peptide-HLA class I tetramers have been used to study immune responses to viruses in humans. This approach has indicated consecutive stages of human CD8(+) T-cell development in acute viral infection and has illustrated the

  6. Micronutrient supplementation and T-cell mediated immune responses in patients with tuberculosis in Tanzania

    Science.gov (United States)

    Limited studies exist regarding whether incorporating micronutrient supplements during tuberculosis (TB) treatment may improve cell-mediated immune response. We examine the effect of micronutrient supplementation on lymphocyte proliferation response to mycobacteria or T cell mitogens in a randomize...

  7. An unexpected antibody response to an engineered influenza virus modifies CD8+ T cell responses.

    Science.gov (United States)

    Thomas, Paul G; Brown, Scott A; Yue, Wen; So, Jenny; Webby, Richard J; Doherty, Peter C

    2006-02-21

    The ovalbumin(323-339) peptide that binds H2I-A(b) was engineered into the globular heads of hemagglutinin (H) molecules from serologically non-cross-reactive H1N1 and H3N2 influenza A viruses, the aim being to analyze recall CD4+ T cell responses in a virus-induced respiratory disease. Prime/challenge experiments with these H1ova and H3ova viruses in H2(b) mice gave the predicted, ovalbumin-specific CD4+ T cell response but showed an unexpectedly enhanced, early expansion of viral epitope-specific CD8+ T cells in spleen and a greatly diminished inflammatory process in the virus-infected respiratory tract. At the same time, the primary antibody response to the H3N2 challenge virus was significantly reduced, an effect that has been associated with preexisting neutralizing antibody in other experimental systems. Analysis of serum from the H1ova-primed mice showed low-level binding to H3ova but not to the wild-type H3N2 virus. Experiments with CD4+ T cell-depleted and Ig-/- mice indicated that this cross-reactive Ig is indeed responsible for the modified pathogenesis after respiratory challenge. Furthermore, the effect does not seem to be virus-dose related, although it does require infection. These findings suggest intriguing possibilities for vaccination and, at the same time, emphasize that engineered modifications in viruses may have unintended immunological consequences.

  8. Smac mimetics and oncolytic viruses synergize in driving anticancer T-cell responses through complementary mechanisms.

    Science.gov (United States)

    Kim, Dae-Sun; Dastidar, Himika; Zhang, Chunfen; Zemp, Franz J; Lau, Keith; Ernst, Matthias; Rakic, Andrea; Sikdar, Saif; Rajwani, Jahanara; Naumenko, Victor; Balce, Dale R; Ewanchuk, Ben W; Taylor, Pankaj; Yates, Robin M; Jenne, Craig; Gafuik, Chris; Mahoney, Douglas J

    2017-08-24

    Second mitochondrial activator of caspase (Smac)-mimetic compounds and oncolytic viruses were developed to kill cancer cells directly. However, Smac-mimetic compound and oncolytic virus therapies also modulate host immune responses in ways we hypothesized would complement one another in promoting anticancer T-cell immunity. We show that Smac-mimetic compound and oncolytic virus therapies synergize in driving CD8 + T-cell responses toward tumors through distinct activities. Smac-mimetic compound treatment with LCL161 reinvigorates exhausted CD8 + T cells within immunosuppressed tumors by targeting tumor-associated macrophages for M1-like polarization. Oncolytic virus treatment with vesicular stomatitis virus (VSV ΔM51 ) promotes CD8 + T-cell accumulation within tumors and CD8 + T-cell activation within the tumor-draining lymph node. When combined, LCL161 and VSV ΔM51 therapy engenders CD8 + T-cell-mediated tumor control in several aggressive mouse models of cancer. Smac-mimetic compound and oncolytic virus therapies are both in clinical development and their combination therapy represents a promising approach for promoting anticancer T-cell immunity.Oncolytic viruses (OV) and second mitochondrial activator of caspase (Smac)-mimetic compounds (SMC) synergistically kill cancer cells directly. Here, the authors show that SMC and OV therapies combination also synergize in vivo by promoting anticancer immunity through an increase in CD8 + T-cell response.

  9. Signals involved in T cell activation. I. Phorbol esters enhance responsiveness but cannot replace intact accessory cells in the induction of mitogen-stimulated T cell proliferation

    International Nuclear Information System (INIS)

    Davis, L.; Lipsky, P.E.

    1985-01-01

    The role of accessory cells (AC) in the initiation of mitogen-induced T cell proliferation was examined by comparing the effect of intact macrophages (M phi) with that of 4-β-phorbol 12-myristate 13-acetate (PMA). In high-density cultures, purified guinea pig T cells failed to proliferate in response to stimulation with phytohemagglutinin (PHA), concanavalin A (Con A), or PMA alone. The addition of M phi to PHA or Con A but not PMA-stimulated cultures restored T cell proliferation. The addition of PMA to high-density T cell cultures stimulated with PHA or Con A also permitted [ 3 H]thymidine incorporation, but was less effective than intact M phi in this regard. This action of PMA was dependent on the small number of Ac contaminating the T cell cultures as evidenced by the finding that PMA could not support mitogen responsiveness of T cells that had been depleted of Ia-bearing cells by panning, even when these cells were cultured at high density. A low-density culture system was used to examine in greater detail the possibility that PMA could completely substitute for M phi in promoting T cells activation. In low-density cultures, mitogen-induced T cell proliferation required intact M phi. These results support a model of T cell activation in which AC play at least two distinct roles. The initiation of the response requires a signal conveyed by an intact M phi, which cannot be provided by either a M phi supernatant factor or PMA. The response can be amplified by additional M phi or M phi supernatant factors. PMA can substitute for M phi in this regard and can provide the signal necessary for amplification of T cell proliferation supported by small numbers of intact AC

  10. Multifunctional T-cell Analyses to Study Response and Progression in Adoptive Cell Transfer Immunotherapy

    Science.gov (United States)

    Ma, Chao; Cheung, Ann F.; Chodon, Thinle; Koya, Richard C.; Wu, Zhongqi; Ng, Charles; Avramis, Earl; Cochran, Alistair J.; Witte, Owen N.; Baltimore, David; Chmielowski, Bartosz; Economou, James S.; Comin-Anduix, Begonya; Ribas, Antoni; Heath, James R.

    2013-01-01

    Adoptive cell transfer (ACT) of genetically engineered T cells expressing cancer-specific T-cell receptors (TCR) is a promising cancer treatment. Here, we investigate the in vivo functional activity and dynamics of the transferred cells by analyzing samples from 3 representative patients with melanoma enrolled in a clinical trial of ACT with TCR transgenic T cells targeted against the melanosomal antigen MART-1. The analyses included evaluating 19 secreted proteins from individual cells from phenotypically defined T-cell subpopulations, as well as the enumeration of T cells with TCR antigen specificity for 36 melanoma antigens. These analyses revealed the coordinated functional dynamics of the adoptively transferred, as well as endogenous, T cells, and the importance of highly functional T cells in dominating the antitumor immune response. This study highlights the need to develop approaches to maintaining antitumor T-cell functionality with the aim of increasing the long-term efficacy of TCR-engineered ACT immunotherapy. SIGNIFICANCE A longitudinal functional study of adoptively transferred TCR–engineered lymphocytes yielded revealing snapshots for understanding the changes of antitumor responses over time in ACT immunotherapy of patients with advanced melanoma. PMID:23519018

  11. Regulation of T cell response to leishmania antigens by determinants of histocompatibility leukocyte class I and II molecules

    Directory of Open Access Journals (Sweden)

    Bacellar O.

    1998-01-01

    Full Text Available It has been shown that HLA class I molecules play a significant role in the regulation of the proliferation of T cells activated by mitogens and antigens. We evaluated the ability of mAb to a framework determinant of HLA class I molecules to regulate T cell proliferation and interferon gamma (IFN-g production against leishmania, PPD, C. albicans and tetanus toxoid antigens in patients with tegumentary leishmaniasis and healthy subjects. The anti-major histocompatibility complex (MHC mAb (W6/32 suppressed lymphocyte proliferation by 90% in cultures stimulated with aCD3, but the suppression was variable in cultures stimulated with leishmania antigen. This suppression ranged from 30-67% and was observed only in 5 of 11 patients. IFN-g production against leishmania antigen was also suppressed by anti-HLA class I mAb. In 3 patients IFN-g levels were suppressed by more than 60%, while in the other 2 cultures IFN-g levels were 36 and 10% lower than controls. The suppression by HLA class I mAb to the proliferative response in leishmaniasis patients and in healthy controls varied with the antigens and the patients or donors tested. To determine whether the suppression is directed at antigen presenting cells (APCs or at the responding T cells, experiments with antigen-primed non-adherent cells, separately incubated with W6/32, were performed. Suppression of proliferation was only observed when the W6/32 mAb was added in the presence of T cells. These data provide evidence that a mAb directed at HLA class I framework determinants can suppress proliferation and cytokine secretion in response to several antigens.

  12. Modification of T cell responses by stem cell mobilization requires direct signaling of the T cell by G-CSF and IL-10

    DEFF Research Database (Denmark)

    MacDonald, Kelli P.A.; Le Texier, Laetitia; Zhang, Ping

    2014-01-01

    The majority of allogeneic stem cell transplants are currently undertaken using G-CSF mobilized peripheral blood stem cells. G-CSF has diverse biological effects on a broad range of cells and IL-10 is a key regulator of many of these effects. Using mixed radiation chimeras in which...... the hematopoietic or nonhematopoietic compartments were wild-type, IL-10(-/-), G-CSFR(-/-), or combinations thereof we demonstrated that the attenuation of alloreactive T cell responses after G-CSF mobilization required direct signaling of the T cell by both G-CSF and IL-10. IL-10 was generated principally by radio......, stem cell mobilization with the CXCR4 antagonist AMD3100 did not alter the donor T cell's ability to induce acute GVHD. These studies provide an explanation for the effects of G-CSF on T cell function and demonstrate that IL-10 is required to license regulatory function but T cell production of IL-10...

  13. Regulation of the CD8+ T cell responses against Plasmodium liver stages in mice.

    Science.gov (United States)

    Morrot, Alexandre; Zavala, Fidel

    2004-12-01

    CD8+ T cells induced by immunization with Plasmodium sporozoites play a major role in protective immunity against parasite infection, inhibiting the development of liver stages. The activation of these T cells is initiated just a few hours after exposure to parasites and progresses rapidly through a tightly regulated program. Effector functions in CD8+ T are detectable as early as 24 h after immunization and this event is followed 24-48 h later by an accelerated expansion of the CD8+ T cell numbers which reaches a peak 4-5 days after priming. Concomitantly with the development of anti-parasite activity, CD8+ T cells acquire a self-regulatory role limiting the magnitude of the CD8+ T cell response. Once activated, CD8+ T cells strongly inhibit the priming of additional naive CD8+ T cells by competing for antigen presenting cells. On days 6-8 after immunization, a sudden contraction of this T cell response occurs due to programmed cell death of 70-80% of the activated cells. After this contraction phase, 15-20 days after priming, activated cells establish memory populations. The development and maintenance of these memory populations strictly depends on the presence of CD4+ T cells and IL-4, and probably also IL-7, IL-15 and IL-2. These cytokines, some of which are produced by CD4+ T cells, provide signals to prevents apoptosis and also induce the differentiation of memory sub-populations, most of which acquire definitive phenotypes 20-30 days after immunization.

  14. Stomatin-like protein 2 deficiency in T cells is associated with altered mitochondrial respiration and defective CD4+ T cell responses.

    Science.gov (United States)

    Christie, Darah A; Mitsopoulos, Panagiotis; Blagih, Julianna; Dunn, Stanley D; St-Pierre, Julie; Jones, Russell G; Hatch, Grant M; Madrenas, Joaquín

    2012-11-01

    Stomatin-like protein 2 (SLP-2) is a mostly mitochondrial protein that regulates mitochondrial biogenesis and function and modulates T cell activation. To determine the mechanism of action of SLP-2, we generated T cell-specific SLP-2-deficient mice. These mice had normal numbers of thymocytes and T cells in the periphery. However, conventional SLP-2-deficient T cells had a posttranscriptional defect in IL-2 production in response to TCR ligation, and this translated into reduced CD4(+) T cell responses. SLP-2 deficiency was associated with impaired cardiolipin compartmentalization in mitochondrial membranes, decreased levels of the NADH dehydrogenase (ubiquinone) iron-sulfur protein 3, NADH dehydrogenase (ubiquinone) 1β subcomplex subunit 8, and NADH dehydrogenase (ubiquinone) 1α subcomplex subunit 9 of respiratory complex I, and decreased activity of this complex as well as of complex II plus III of the respiratory chain. In addition, SLP-2-deficient T cells showed a significant increase in uncoupled mitochondrial respiration and a greater reliance on glycolysis. Based on these results, we propose that SLP-2 organizes the mitochondrial membrane compartmentalization of cardiolipin, which is required for optimal assembly and function of respiratory chain complexes. This function, in T cells, helps to ensure proper metabolic response during activation.

  15. RAGE Expression in Human T Cells: A Link between Environmental Factors and Adaptive Immune Responses

    Science.gov (United States)

    Akirav, Eitan M.; Preston-Hurlburt, Paula; Garyu, Justin; Henegariu, Octavian; Clynes, Raphael; Schmidt, Ann Marie; Herold, Kevan C.

    2012-01-01

    The Receptor for Advanced Glycation Endproducts (RAGE) is a scavenger ligand that binds glycated endproducts as well as molecules released during cell death such as S100b and HMGB1. RAGE is expressed on antigen presenting cells where it may participate in activation of innate immune responses but its role in adaptive human immune responses has not been described. We have found that RAGE is expressed intracellularly in human T cells following TCR activation but constitutively on T cells from patients with diabetes. The levels of RAGE on T cells from patients with diabetes are not related to the level of glucose control. It co-localizes to the endosomes. Its expression increases in activated T cells from healthy control subjects but bystander cells also express RAGE after stimulation of the antigen specific T cells. RAGE ligands enhance RAGE expression. In patients with T1D, the level of RAGE expression decreases with T cell activation. RAGE+ T cells express higher levels of IL-17A, CD107a, and IL-5 than RAGE− cells from the same individual with T1D. Our studies have identified the expression of RAGE on adaptive immune cells and a role for this receptor and its ligands in modulating human immune responses. PMID:22509345

  16. Dickkopf-3, a tissue-derived modulator of local T cell responses

    Directory of Open Access Journals (Sweden)

    Michael eMeister

    2015-02-01

    Full Text Available The adaptive immune system protects organisms from harmful environmental insults. In parallel, regulatory mechanisms control immune responses in order to assure preservation of organ integrity. Yet, molecules involved in the control of T cell responses in peripheral tissues are poorly characterized. Here, we investigated the function of Dickkopf-3 in the modulation of local T cell reactivity. Dkk3 is a secreted, mainly tissue derived protein with highest expression in organs considered as immune privileged such as the eye, embryo, placenta and brain. While T cell development and activation status in naïve Dkk3 deficient mice was comparable to littermate controls, we found that Dkk3 contributes to the immunosuppressive microenvironment that protects transplanted, class-I mismatched embryoid bodies from T cell mediated rejection. Moreover, genetic deletion or antibody mediated neutralization of Dkk3 led to an exacerbated experimental autoimmune encephalomyelitis (EAE. This phenotype was accompanied by a change of T cell polarization displayed by an increase of IFNγ producing T cells within in the CNS. In the wild type situation, Dkk3 expression in the brain was up-regulated during the course of EAE in an IFNγ dependent manner. In turn, Dkk3 decreased IFNγ activity and served as part of a negative feedback mechanism. Thus, our findings suggest that Dkk3 functions as a tissue-derived modulator of local CD4+ and CD8+ T cell responses.

  17. T cell Bim levels reflect responses to anti–PD-1 cancer therapy

    Science.gov (United States)

    Dronca, Roxana S.; Liu, Xin; Harrington, Susan M.; Chen, Lingling; Cao, Siyu; Kottschade, Lisa A.; McWilliams, Robert R.; Block, Matthew S.; Nevala, Wendy K.; Thompson, Michael A.; Mansfield, Aaron S.; Park, Sean S.; Markovic, Svetomir N.

    2016-01-01

    Immune checkpoint therapy with PD-1 blockade has emerged as an effective therapy for many advanced cancers; however, only a small fraction of patients achieve durable responses. To date, there is no validated blood-based means of predicting the response to PD-1 blockade. We report that Bim is a downstream signaling molecule of the PD-1 pathway, and its detection in T cells is significantly associated with expression of PD-1 and effector T cell markers. High levels of Bim in circulating tumor-reactive (PD-1+CD11ahiCD8+) T cells were prognostic of poor survival in patients with metastatic melanoma who did not receive anti–PD-1 therapy and were also predictive of clinical benefit in patients with metastatic melanoma who were treated with anti–PD-1 therapy. Moreover, this circulating tumor-reactive T cell population significantly decreased after successful anti–PD-1 therapy. Our study supports a crucial role of Bim in both T cell activation and apoptosis as regulated by PD-1 and PD-L1 interactions in effector CD8+ T cells. Measurement of Bim levels in circulating T cells of patients with cancer may provide a less invasive strategy to predict and monitor responses to anti–PD-1 therapy, although future prospective analyses are needed to validate its utility. PMID:27182556

  18. Shaping Successful and Unsuccessful CD8 T Cell Responses Following Infection

    OpenAIRE

    Cox, Maureen A.; Zajac, Allan J.

    2010-01-01

    CD8 T cells play a vital role in the immunological protection against intracellular pathogens. Ideally, robust effector responses are induced, which eradicate the pathogen, and durable memory CD8 T cells are also established, which help confer protection against subsequent reinfection. The quality and magnitude of these responses is dictated by multiple factors, including their initial interactions with professional antigen-presenting cells, as well as the cytokine milieu and availability of ...

  19. Deletion of BCG Hip1 protease enhances dendritic cell and CD4 T cell responses.

    Science.gov (United States)

    Bizzell, Erica; Sia, Jonathan Kevin; Quezada, Melanie; Enriquez, Ana; Georgieva, Maria; Rengarajan, Jyothi

    2017-12-28

    Dendritic cells (DCs) play a key role in the generation of CD4 T cell responses to pathogens. Mycobacterium tuberculosis (Mtb) harbors immune evasion mechanisms that impair DC responses and prevent optimal CD4 T cell immunity. The vaccine strain Mycobacterium bovis Bacille Calmette-Guérin (BCG) shares many of the immune evasion proteins utilized by Mtb, but the role of these proteins in DC and T cell responses elicited by BCG is poorly understood. We previously reported that the Mtb serine protease, Hip1, promotes sub-optimal DC responses during infection. Here, we tested the hypothesis that BCG Hip1 modulates DC functions and prevents optimal antigen-specific CD4 T cell responses that limit the immunogenicity of BCG. We generated a strain of BCG lacking hip1 (BCGΔhip1) and show that it has superior capacity to induce DC maturation and cytokine production compared with the parental BCG. Furthermore, BCGΔhip1-infected DCs were more effective at driving the production of IFN-γ and IL-17 from antigen-specific CD4 T cells in vitro. Mucosal transfer of BCGΔhip1-infected DCs into mouse lungs induced robust CD4 T cell activation in vivo and generated antigen-specific polyfunctional CD4 T cell responses in the lungs. Importantly, BCGΔhip1-infected DCs enhanced control of pulmonary bacterial burden following Mtb aerosol challenge compared with the transfer of BCG-infected DCs. These results reveal that BCG employs Hip1 to impair DC activation, leading to attenuated lung CD4 T cell responses with limited capacity to control Mtb burden after challenge. ©2017 Society for Leukocyte Biology.

  20. Highly-Immunogenic Virally-Vectored T-cell Vaccines Cannot Overcome Subversion of the T-cell Response by HCV during Chronic Infection

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    Leo Swadling

    2016-08-01

    Full Text Available An effective therapeutic vaccine for the treatment of chronic hepatitis C virus (HCV infection, as an adjunct to newly developed directly-acting antivirals (DAA, or for the prevention of reinfection, would significantly reduce the global burden of disease associated with chronic HCV infection. A recombinant chimpanzee adenoviral (ChAd3 vector and a modified vaccinia Ankara (MVA, encoding the non-structural proteins of HCV (NSmut, used in a heterologous prime/boost regimen induced multi-specific, high-magnitude, durable HCV-specific CD4+ and CD8+ T-cell responses in healthy volunteers, and was more immunogenic than a heterologous Ad regimen. We now assess the immunogenicity of this vaccine regimen in HCV infected patients (including patients with a low viral load suppressed with interferon/ribavirin therapy, determine T-cell cross-reactivity to endogenous virus, and compare immunogenicity with that observed previously in both healthy volunteers and in HCV infected patients vaccinated with the heterologous Ad regimen. Vaccination of HCV infected patients with ChAd3-NSmut/MVA-NSmut was well tolerated. Vaccine-induced HCV-specific T-cell responses were detected in 8/12 patients; however, CD4+ T-cell responses were rarely detected, and the overall magnitude of HCV-specific T-cell responses was markedly reduced when compared to vaccinated healthy volunteers. Furthermore, HCV-specific cells had a distinct partially-functional phenotype (lower expression of activation markers, granzyme B, and TNFα production, weaker in vitro proliferation, and higher Tim3 expression, with comparable Tbet and Eomes expression compared to healthy volunteers. Robust anti-vector T-cells and antibodies were induced, showing that there is no global defect in immunity. The level of viremia at the time of vaccination did not correlate with the magnitude of the vaccine-induced T-cell response. Full-length, next-generation sequencing of the circulating virus demonstrated that T-cells

  1. Highly-Immunogenic Virally-Vectored T-cell Vaccines Cannot Overcome Subversion of the T-cell Response by HCV during Chronic Infection.

    Science.gov (United States)

    Swadling, Leo; Halliday, John; Kelly, Christabel; Brown, Anthony; Capone, Stefania; Ansari, M Azim; Bonsall, David; Richardson, Rachel; Hartnell, Felicity; Collier, Jane; Ammendola, Virginia; Del Sorbo, Mariarosaria; Von Delft, Annette; Traboni, Cinzia; Hill, Adrian V S; Colloca, Stefano; Nicosia, Alfredo; Cortese, Riccardo; Klenerman, Paul; Folgori, Antonella; Barnes, Eleanor

    2016-08-02

    An effective therapeutic vaccine for the treatment of chronic hepatitis C virus (HCV) infection, as an adjunct to newly developed directly-acting antivirals (DAA), or for the prevention of reinfection, would significantly reduce the global burden of disease associated with chronic HCV infection. A recombinant chimpanzee adenoviral (ChAd3) vector and a modified vaccinia Ankara (MVA), encoding the non-structural proteins of HCV (NSmut), used in a heterologous prime/boost regimen induced multi-specific, high-magnitude, durable HCV-specific CD4+ and CD8+ T-cell responses in healthy volunteers, and was more immunogenic than a heterologous Ad regimen. We now assess the immunogenicity of this vaccine regimen in HCV infected patients (including patients with a low viral load suppressed with interferon/ribavirin therapy), determine T-cell cross-reactivity to endogenous virus, and compare immunogenicity with that observed previously in both healthy volunteers and in HCV infected patients vaccinated with the heterologous Ad regimen. Vaccination of HCV infected patients with ChAd3-NSmut/MVA-NSmut was well tolerated. Vaccine-induced HCV-specific T-cell responses were detected in 8/12 patients; however, CD4+ T-cell responses were rarely detected, and the overall magnitude of HCV-specific T-cell responses was markedly reduced when compared to vaccinated healthy volunteers. Furthermore, HCV-specific cells had a distinct partially-functional phenotype (lower expression of activation markers, granzyme B, and TNFα production, weaker in vitro proliferation, and higher Tim3 expression, with comparable Tbet and Eomes expression) compared to healthy volunteers. Robust anti-vector T-cells and antibodies were induced, showing that there is no global defect in immunity. The level of viremia at the time of vaccination did not correlate with the magnitude of the vaccine-induced T-cell response. Full-length, next-generation sequencing of the circulating virus demonstrated that T-cells were

  2. Interferon-Beta Therapy of Multiple Sclerosis Patients Improves the Responsiveness of T Cells for Immune Suppression by Regulatory T Cells

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    Bettina Trinschek

    2015-07-01

    Full Text Available Multiple sclerosis (MS is an inflammatory autoimmune disease characterized by imbalanced immune regulatory networks, and MS patient-derived T effector cells are inefficiently suppressed through regulatory T cells (Treg, a phenomenon known as Treg resistance. In the current study we investigated T cell function in MS patients before and after interferon-beta therapy. We compared cytokine profile, responsiveness for Treg-mediated suppression ex vivo and evaluated reactivity of T cells in vivo using a humanized mouse model. We found that CD4+ and CD8+ T cells of therapy-naive MS patients were resistant to Treg-mediated suppression. Treg resistance is associated with an augmented IL-6 production, enhanced IL-6 receptor expression, and increased PKB/c-Akt phosphorylation. These parameters as well as responsiveness of T cells to Treg-mediated suppression were restored after interferon-beta therapy of MS patients. Following transfer into immunodeficient mice, MS T cells induced a lethal graft versus host disease (GvHD and in contrast to T cells of healthy volunteers, this aggressive T cell response could not be controlled by Treg, but was abolished by anti-IL-6 receptor antibodies. However, magnitude and lethality of GvHD induced by MS T cells was significantly decreased after interferon-beta therapy and the reaction was prevented by Treg activation in vivo. Our data reveals that interferon-beta therapy improves the immunoregulation of autoaggressive T effector cells in MS patients by changing the IL-6 signal transduction pathway, thus restoring their sensitivity to Treg-mediated suppression.

  3. Illuminating the petite picture of T cell memory responses to Listeria monocytogenes.

    Science.gov (United States)

    Tufail, Saba; Badrealam, Khan Farheen; Owais, Mohammad; Zubair, Swaleha

    2013-01-01

    The ease to culture, moderately less safety constraints in handling, and above all, hurdle free induction of an anticipated infection in mouse rendered Listeria monocytogenes the rank of a model organism for studying a variety of host immune responses. Listeria monocytogenes being an intracellular pathogen evokes potent CD8 T cell response during which CD8 T cells pass through a massive expansion phase. This is generally followed by contraction phase wherein majority of activated cells undergo apoptosis leaving behind a population of memory CD8 T cells that has potential to confer enhanced protection upon reencounter with the same pathogen. Functional attributes of various cytokines, transcription factors, receptors, adaptors, and effectors pertaining to the generation of robust memory T cell response have begun to be unravelled for better understanding of memory and opening avenues to create superior vaccine strategies. This review is an attempt to unveil related discoveries along with updating recent advances on this issue.

  4. MHC class I-presented tumor antigen appraisable for T-cell responses against ovarian cancer

    Directory of Open Access Journals (Sweden)

    Jing Yao Wang

    2015-08-01

    Full Text Available The purpose of this study is to assess whether MHC class I-presented tumor antigen is appraisable for T-cell responses against ovarian cancer. In ovarian cancer cell, human leukocyte antigen A2 (HLA-A2 associated with peptides was used to promote the activation of naive T cells so as to activate antigen-specific T cells. 7 or 4 patients were observed grade 1 or 2 injection site reactions, respectively. 5, 2 or 1 patients were observed grade 1, 2 or 3 pain reactions, respectively. 4 or 1 patients were observed grade 1 or 2 induration reactions. Total number mean value of patients experiencing response to the particular peptide was 7.73, and total number mean value of peptides to which the patients responded was 7.45. MHC class I-presented tumor antigen is appraisable for T-cell responses against ovarian cancer in China.

  5. Low-strength T-cell activation promotes Th17 responses.

    Science.gov (United States)

    Purvis, Harriet A; Stoop, Jeroen N; Mann, Jelena; Woods, Steven; Kozijn, Anne E; Hambleton, Sophie; Robinson, John H; Isaacs, John D; Anderson, Amy E; Hilkens, Catharien M U

    2010-12-02

    We show that the strength of T-cell stimulation determines the capability of human CD4(+) T cells to become interleukin-17 (IL-17) producers. CD4(+) T cells received either high- (THi) or low (TLo)-strength stimulation via anti-CD3/CD28 beads or dendritic cells pulsed with superantigen in the presence of pro-Th17 cytokines IL-1β, transforming growth factor β, and IL-23. We found that TLo, but not THi, stimulation profoundly promoted Th17 responses by enhancing both the relative proportion and total number of Th17 cells. Titration of anti-CD3 revealed that low TCR signaling promoted Th17 cells, but only in the presence of anti-CD28. Impaired IL-17 production in THi cells could not be explained by high levels of Foxp3 or transforming growth factor β-latency-associated peptide expressed by THi cells. Nuclear factor of activated T cells was translocated to the nucleus in both THi and TLo cells, but only bound to the proximal region of the IL-17 promoter in TLo cells. The addition of a Ca(2+) ionophore under TLo conditions reversed the pro-Th17 effect, suggesting that high Ca(2+) signaling impairs Th17 development. Although our data do not distinguish between priming of naive T cells versus expansion/differentiation of memory T cells, our results clearly establish an important role for the strength of T-cell activation in regulating Th17 responses.

  6. Responses to recipient and donor B cells by genetically donor T cells from human haploidentical chimeras

    International Nuclear Information System (INIS)

    Schiff, S.; Sampson, H.; Buckley, R.

    1986-01-01

    Following administration of haploidentical stem cells to infants with severe combined immunodeficiency (SCID), mature T cells of donor karyotype appear later in the recipient without causing graft-versus-host disease. To investigate the effect of the host environment on the responsiveness of these genetically donor T cells, blood B and T lymphocytes from 6 SCID recipients, their parental donors and unrelated controls were purified by double SRBC rosetting. T cells were stimulated by irradiated B cells at a 1:1 ratio in 6 day cultures. Engrafted T cells of donor karyotype gave much smaller responses to irradiated genetically recipient B cells than did fresh donor T cells. Moreover, engrafted T cells of donor karyotype from two of the three SCIDs who are longest post-transplantation responded more vigorously (14,685 and 31,623 cpm) than fresh donor T cells (5141 and 22,709 cpm) to donor B cells. These data indicate that T lymphocytes which have matured from donor stem cells in the recipient microenvironment behave differently from those that have matured in the donor

  7. The transcription factor BATF modulates cytokine-mediated responses in T cells.

    Science.gov (United States)

    Sopel, Nina; Graser, Anna; Mousset, Stephanie; Finotto, Susetta

    2016-08-01

    The transcription factor BATF (basic leucine zipper transcription factor, ATF-like), belongs to the AP-1 family of transcription factors and has been shown to be predominantly expressed in cells of haematopoietic origin, especially in B and T cells. In studies using Batf-deficient mice, a profound defect in the differentiation of T helper cells type 17 (Th17) and follicular T helper cells (Tfh) was described, as well as an impairment of antibody production with switched isotypes. More recently BATF has been described to influence also Th2 and Th9 responses in models of murine experimental asthma. In CD8(+) T cells BATF has been found associated with anti-viral responses. This review summarizes the role of BATF in CD4(+) T cell subsets and in CD8(+) T cells, with particular focus on this transcription factor in the setting of allergic asthma. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    The CD3gamma di-leucine-based motif plays a central role in TCR down-regulation. However, little is understood about the role of the CD3gamma di-leucine-based motif in physiological T cell responses. In this study, we show that the expansion in numbers of virus-specific CD8(+) T cells is impaired...... molecule Bcl-2. This resulted in a 2-fold reduction in the clonal expansion of virus-specific CD8(+) T cells during the acute phase of vesicular stomatitis virus and lymphocytic choriomeningitis virus infections. These results identify an important role of CD3gamma-mediated TCR down-regulation in virus......-specific CD8(+) T cell responses....

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    The CD3gamma di-leucine-based motif plays a central role in TCR down-regulation. However, little is understood about the role of the CD3gamma di-leucine-based motif in physiological T cell responses. In this study, we show that the expansion in numbers of virus-specific CD8(+) T cells is impaired...... molecule Bcl-2. This resulted in a 2-fold reduction in the clonal expansion of virus-specific CD8(+) T cells during the acute phase of vesicular stomatitis virus and lymphocytic choriomeningitis virus infections. These results identify an important role of CD3gamma-mediated TCR down-regulation in virus......-specific CD8(+) T cell responses....

  10. A Myc-dependent division timer complements a cell-death timer to regulate T cell and B cell responses.

    Science.gov (United States)

    Heinzel, Susanne; Binh Giang, Tran; Kan, Andrey; Marchingo, Julia M; Lye, Bryan K; Corcoran, Lynn M; Hodgkin, Philip D

    2017-01-01

    T lymphocytes and B lymphocytes integrate activating signals to control the size of their proliferative response. Here we report that such control was achieved by timed changes in the production rate of cell-cycle-regulating proto-oncoprotein Myc, with division cessation occurring when Myc levels fell below a critical threshold. The changing pattern of the level of Myc was not affected by cell division, which identified the regulating mechanism as a cell-intrinsic, heritable temporal controller. Overexpression of Myc in stimulated T cells and B cells did not sustain cell proliferation indefinitely, as a separate 'time-to-die' mechanism, also heritable, was programmed after lymphocyte activation and led to eventual cell loss. Together the two competing cell-intrinsic timed fates created the canonical T cell and B cell immune-response pattern of rapid growth followed by loss of most cells. Furthermore, small changes in these timed processes by regulatory signals, or by oncogenic transformation, acted in synergy to greatly enhance cell numbers over time.

  11. Cannabidiol (CBD) induces functional Tregs in response to low-level T cell activation.

    Science.gov (United States)

    Dhital, Saphala; Stokes, John V; Park, Nogi; Seo, Keun Seok; Kaplan, Barbara L F

    2017-02-01

    Many effects of the non-psychoactive cannabinoid, cannabidiol (CBD), have been described in immune responses induced by strong immunological stimuli. It has also been shown that CBD enhances IL-2 production in response to low-level T cell stimulation. Since IL-2, in combination with TGF-β1, are critical for Treg induction, we hypothesized that CBD would induce CD4 + CD25 + FOXP3 + Tregs in response to low-level stimulation. Low-level T cell stimulation conditions were established based on minimal CD25 expression in CD4 + cells using suboptimal PMA/Io (4nM/0.05μM, S/o), ultrasuboptimal PMA/Io (1nM/0.0125μM, Us/o) or soluble anti-CD3/28 (400-800ng each, s3/28). CBD increased CD25 + FOXP3 + cells from CD4 + , CD4 + CD25 + , and CD4 + CD25 - T cells, as well as in CD4 + T cells derived from FOXP3-GFP mice. Most importantly, the Us/o+CBD-induced CD4 + CD25 + Tregs robustly suppressed responder T cell proliferation, demonstrating that the mechanism by which CBD is immunosuppressive under low-level T cell stimulation involves induction of functional Tregs. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. System-wide Analysis of the T Cell Response

    Directory of Open Access Journals (Sweden)

    Ruxandra Covacu

    2016-03-01

    Full Text Available The T cell receptor (TCR controls the cellular adaptive immune response to antigens, but our understanding of TCR repertoire diversity and response to challenge is still incomplete. For example, TCR clones shared by different individuals with minimal alteration to germline gene sequences (public clones are detectable in all vertebrates, but their significance is unknown. Although small in size, the zebrafish TCR repertoire is controlled by processes similar to those operating in mammals. Thus, we studied the zebrafish TCR repertoire and its response to stimulation with self and foreign antigens. We found that cross-reactive public TCRs dominate the T cell response, endowing a limited TCR repertoire with the ability to cope with diverse antigenic challenges. These features of vertebrate public TCRs might provide a mechanism for the rapid generation of protective T cell immunity, allowing a short temporal window for the development of more specific private T cell responses.

  13. rBCG induces strong antigen-specific T cell responses in rhesus macaques in a prime-boost setting with an adenovirus 35 tuberculosis vaccine vector.

    Directory of Open Access Journals (Sweden)

    Isabelle Magalhaes

    Full Text Available BACKGROUND: BCG vaccination, combined with adenoviral-delivered boosts, represents a reasonable strategy to augment, broaden and prolong immune protection against tuberculosis (TB. We tested BCG (SSI1331 (in 6 animals, delivered intradermally and a recombinant (rBCG AFRO-1 expressing perfringolysin (in 6 animals followed by two boosts (delivered intramuscullary with non-replicating adenovirus 35 (rAd35 expressing a fusion protein composed of Ag85A, Ag85B and TB10.4, for the capacity to induce antigen-specific cellular immune responses in rhesus macaques (Macaca mulatta. Control animals received diluent (3 animals. METHODS AND FINDINGS: Cellular immune responses were analyzed longitudinally (12 blood draws for each animal using intracellular cytokine staining (TNF-alpha, IL-2 and IFN-gamma, T cell proliferation was measured in CD4(+, CD8alpha/beta(+, and CD8alpha/alpha(+ T cell subsets and IFN-gamma production was tested in 7 day PBMC cultures (whole blood cell assay, WBA using Ag85A, Ag85B, TB10.4 recombinant proteins, PPD or BCG as stimuli. Animals primed with AFRO-1 showed i increased Ag85B-specific IFN-gamma production in the WBA assay (median >400 pg/ml for 6 animals one week after the first boost with adenoviral-delivered TB-antigens as compared to animals primed with BCG (<200 pg/ml, ii stronger T cell proliferation in the CD8alpha/alpha(+ T cell subset (proliferative index 17% as compared to BCG-primed animals (proliferative index 5% in CD8alpha/alpha(+ T cells. Polyfunctional T cells, defined by IFN-gamma, TNF-alpha and IL-2 production were detected in 2/6 animals primed with AFRO-1 directed against Ag85A/b and TB10.4; 4/6 animals primed with BCG showed a Ag85A/b responses, yet only a single animal exhibited Ag85A/b and TB10.4 reactivity. CONCLUSION: AFRO-1 induces qualitatively and quantitatively different cellular immune responses as compared with BCG in rhesus macaques. Increased IFN-gamma-responses and antigen-specific T cell

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

    Science.gov (United States)

    Bentzen, Amalie Kai; Hadrup, Sine Reker

    2017-05-01

    T cell-mediated recognition of peptide-major histocompatibility complex (pMHC) class I and II molecules is crucial for the control of intracellular pathogens and cancer, as well as for stimulation and maintenance of efficient cytotoxic responses. Such interactions may also play a role in the development of autoimmune diseases. Novel insights into this mechanism are crucial to understanding disease development and establishing new treatment strategies. MHC multimers have been used for detection of antigen-responsive T cells since the first report by Altman et al. showed that tetramerization of pMHC class I molecules provided sufficient stability to T cell receptor (TCR)-pMHC interactions, allowing detection of MHC multimer-binding T cells using flow cytometry. Since this breakthrough the scientific community has aimed for expanding the capacity of MHC multimer-based detection technologies to facilitate large-scale epitope discovery and immune monitoring in limited biological material. Screening of T cell specificity using large libraries of pMHC molecules is suitable for analyses of T cell recognition potentially at genome-wide levels rather than analyses restricted to a selection of model antigens. Such strategies provide novel insights into the immune specificities involved in disease development and response to immunotherapy, and extend fundamental knowledge related to T cell recognition patterns and cross-recognition by TCRs. MHC multimer-based technologies have now evolved from detection of 1-2 different T cell specificities per cell sample, to include more than 1000 evaluable pMHC molecules using novel technologies. Here, we provide an overview of MHC multimer-based detection technologies developed over two decades, focusing primarily on MHC class I interactions.

  15. Direct inhibition of T-cell responses by the Cryptococcus capsular polysaccharide glucuronoxylomannan.

    Directory of Open Access Journals (Sweden)

    Lauren E Yauch

    2006-11-01

    Full Text Available The major virulence factor of the pathogenic fungi Cryptococcus neoformans and C. gattii is the capsule. Glucuronoxylomannan (GXM, the major component of the capsule, is a high-molecular-weight polysaccharide that is shed during cryptococcosis and can persist in patients after successful antifungal therapy. Due to the importance of T cells in the anticryptococcal response, we studied the effect of GXM on the ability of dendritic cells (DCs to initiate a T-cell response. GXM inhibited the activation of cryptococcal mannoprotein-specific hybridoma T cells and the proliferation of OVA-specific OT-II T cells when murine bone marrow-derived DCs were used as antigen-presenting cells. Inhibition of OT-II T-cell proliferation was observed when either OVA protein or OVA323-339 peptide was used as antigen, indicating GXM did not merely prevent antigen uptake or processing. We found that DCs internalize GXM progressively over time; however, the suppressive effect did not require DCs, as GXM directly inhibited T-cell proliferation induced by anti-CD3 antibody, concanavalin A, or phorbol-12-myristate-13-acetate/ionomycin. Analysis of T-cell viability revealed that the reduced proliferation in the presence of GXM was not the result of increased cell death. GXM isolated from each of the four major cryptococcal serotypes inhibited the proliferation of human peripheral blood mononuclear cells stimulated with tetanus toxoid. Thus, we have defined a new mechanism by which GXM can impart virulence: direct inhibition of T-cell proliferation. In patients with cryptococcosis, this could impair optimal cell-mediated immune responses, thereby contributing to the persistence of cryptococcal infections.

  16. Polyfunctional response by ImmTAC (IMCgp100) redirected CD8+and CD4+T cells.

    Science.gov (United States)

    Boudousquie, Caroline; Bossi, Giovanna; Hurst, Jacob M; Rygiel, Karolina A; Jakobsen, Bent K; Hassan, Namir J

    2017-11-01

    The success of immune system-based cancer therapies depends on a broad immune response engaging a range of effector cells and mechanisms. Immune mobilizing monoclonal T cell receptors (TCRs) against cancer (ImmTAC™ molecules: fusion proteins consisting of a soluble, affinity enhanced TCR and an anti-CD3 scFv antibody) were previously shown to redirect CD8 + and CD4 + T cells against tumours. Here we present evidence that IMCgp100 (ImmTAC recognizing a peptide derived from the melanoma-specific protein, gp100, presented by HLA-A*0201) efficiently redirects and activates effector and memory cells from both CD8 + and CD4 + repertoires. Using isolated subpopulations of T cells, we find that both terminally differentiated and effector memory CD8 + T cells redirected by IMCgp100 are potent killers of melanoma cells. Furthermore, CD4 + effector memory T cells elicit potent cytotoxic activity leading to melanoma cell killing upon redirection by IMCgp100. The majority of T cell subsets belonging to both the CD8 + and CD4 + repertoires secrete key pro-inflammatory cytokines (tumour necrosis factor-α, interferon-γ, interleukin-6) and chemokines (macrophage inflammatory protein-1α-β, interferon-γ-inducible protein-10, monocyte chemoattractant protein-1). At an individual cell level, IMCgp100-redirected T cells display a polyfunctional phenotype, which is a hallmark of a potent anti-cancer response. This study demonstrates that IMCgp100 induces broad immune responses that extend beyond the induction of CD8 + T cell-mediated cytotoxicity. These findings are of particular importance because IMCgp100 is currently undergoing clinical trials as a single agent or in combination with check point inhibitors for patients with malignant melanoma. © 2017 The Authors. Immunology Published by John Wiley & Sons Ltd.

  17. Human T cell responses to Japanese encephalitis virus in health and disease.

    Science.gov (United States)

    Turtle, Lance; Bali, Tanushka; Buxton, Gemma; Chib, Savita; Chan, Sajesh; Soni, Mohammed; Hussain, Mohammed; Isenman, Heather; Fadnis, Prachi; Venkataswamy, Manjunatha M; Satishkumar, Vishali; Lewthwaite, Penny; Kurioka, Ayako; Krishna, Srinivasa; Shankar, M Veera; Ahmed, Riyaz; Begum, Ashia; Ravi, Vasanthapuram; Desai, Anita; Yoksan, Sutee; Fernandez, Stefan; Willberg, Christian B; Kloverpris, Henrik N; Conlon, Christopher; Klenerman, Paul; Satchidanandam, Vijaya; Solomon, Tom

    2016-06-27

    Japanese encephalitis (JE) virus (JEV) is an important cause of encephalitis in children of South and Southeast Asia. However, the majority of individuals exposed to JEV only develop mild symptoms associated with long-lasting adaptive immunity. The related flavivirus dengue virus (DENV) cocirculates in many JEV-endemic areas, and clinical data suggest cross-protection between DENV and JEV. To address the role of T cell responses in protection against JEV, we conducted the first full-breadth analysis of the human memory T cell response using a synthetic peptide library. Ex vivo interferon-γ (IFN-γ) responses to JEV in healthy JEV-exposed donors were mostly CD8(+) and targeted nonstructural (NS) proteins, whereas IFN-γ responses in recovered JE patients were mostly CD4(+) and targeted structural proteins and the secreted protein NS1. Among patients, a high quality, polyfunctional CD4(+) T cell response was associated with complete recovery from JE. T cell responses from healthy donors showed a high degree of cross-reactivity to DENV that was less apparent in recovered JE patients despite equal exposure. These data reveal divergent functional CD4(+) and CD8(+) T cell responses linked to different clinical outcomes of JEV infection, associated with distinct targeting and broad flavivirus cross-reactivity including epitopes from DENV, West Nile, and Zika virus. © 2016 Turtle et al.

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

    DEFF Research Database (Denmark)

    Bentzen, Amalie Kai; Hadrup, Sine Reker

    2017-01-01

    detection of 1-2 different T cell specificities per cell sample, to include more than 1000 evaluable pMHC molecules using novel technologies. Here, we provide an overview of MHC multimer-based detection technologies developed over two decades, focusing primarily on MHC class I interactions.......T cell-mediated recognition of peptide-major histocompatibility complex (pMHC) class I and II molecules is crucial for the control of intracellular pathogens and cancer, as well as for stimulation and maintenance of efficient cytotoxic responses. Such interactions may also play a role...... class I molecules provided sufficient stability to T cell receptor (TCR)-pMHC interactions, allowing detection of MHC multimer-binding T cells using flow cytometry. Since this breakthrough the scientific community has aimed for expanding the capacity of MHC multimer-based detection technologies...

  19. Restriction of IL-22-producing T cell responses and differential regulation of regulatory T cell compartments by zinc finger transcription factor Ikaros.

    Science.gov (United States)

    Heller, Jennifer J; Schjerven, Hilde; Li, Shiyang; Lee, Aileen; Qiu, Ju; Chen, Zong-Ming E; Smale, Stephen T; Zhou, Liang

    2014-10-15

    Proper immune responses are needed to control pathogen infection at mucosal surfaces. IL-22-producing CD4(+) T cells play an important role in controlling bacterial infection in the gut; however, transcriptional regulation of these cells remains elusive. In this study, we show that mice with targeted deletion of the fourth DNA-binding zinc finger of the transcription factor Ikaros had increased IL-22-producing, but not IL-17-producing, CD4(+) T cells in the gut. Adoptive transfer of CD4(+) T cells from these Ikaros-mutant mice conferred enhanced mucosal immunity against Citrobacter rodentium infection. Despite an intact in vivo thymic-derived regulatory T cell (Treg) compartment in these Ikaros-mutant mice, TGF-β, a cytokine well known for induction of Tregs, failed to induce Foxp3 expression in Ikaros-mutant CD4(+) T cells in vitro and, instead, promoted IL-22. Aberrant upregulation of IL-21 in CD4(+) T cells expressing mutant Ikaros was responsible, at least in part, for the enhanced IL-22 expression in a Stat3-dependent manner. Genetic analysis using compound mutations further demonstrated that the aryl hydrocarbon receptor, but not RORγt, was required for aberrant IL-22 expression by Ikaros-mutant CD4(+) T cells, whereas forced expression of Foxp3 was sufficient to inhibit this aberrant cytokine production. Together, our data identified new functions for Ikaros in maintaining mucosal immune homeostasis by restricting IL-22 production by CD4(+) T cells. Copyright © 2014 by The American Association of Immunologists, Inc.

  20. Increased sequence diversity coverage improves detection of HIV-Specific T cell responses

    DEFF Research Database (Denmark)

    Frahm, N.; Kaufmann, D.E.; Yusim, K.

    2007-01-01

    The accurate identification of HIV-specific T cell responses is important for determining the relationship between immune response, viral control, and disease progression. HIV-specific immune responses are usually measured using peptide sets based on consensus sequences, which frequently miss res...

  1. Cyperus scariosus Chloroform Fraction Inhibits T cell Responses in ...

    African Journals Online (AJOL)

    Erah

    CSC did not significantly (p < 0.01) suppress Th2 (IL-4) system. Conclusion: The findings from this investigation reveal that C. scariosus causes immunosuppression by inhibiting Th1 cytokines. Keywords: Cyperus scariosus; Immunosuppression; Humoral antibody titre; Cell-mediated immune response; CD 4+ T- helper cells ...

  2. Expanded breadth of the T-cell response to mosaic HIV-1 envelope DNA vaccination

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette [Los Alamos National Laboratory; Fischer, William [Los Alamos National Laboratory; Wallstrom, Timothy [Los Alamos National Laboratory

    2009-01-01

    An effective AIDS vaccine must control highly diverse circulating strains of HIV-1. Among HIV -I gene products, the envelope (Env) protein contains variable as well as conserved regions. In this report, an informatic approach to the design of T-cell vaccines directed to HIV -I Env M group global sequences was tested. Synthetic Env antigens were designed to express mosaics that maximize the inclusion of common potential Tcell epitope (PTE) 9-mers and minimize the inclusion of rare epitopes likely to elicit strain-specific responses. DNA vaccines were evaluated using intracellular cytokine staining (ICS) in inbred mice with a standardized panel of highly conserved 15-mer PTE peptides. I, 2 and 3 mosaic sets were developed that increased theoretical epitope coverage. The breadth and magnitude ofT-cell immunity stimulated by these vaccines were compared to natural strain Env's; additional comparisons were performed on mutant Env's, including gpl60 or gpl45 with or without V regions and gp41 deletions. Among them, the 2 or 3 mosaic Env sets elicited the optimal CD4 and CD8 responses. These responses were most evident in CD8 T cells; the 3 mosaic set elicited responses to an average of 8 peptide pools compared to 2 pools for a set of3 natural Env's. Synthetic mosaic HIV -I antigens can therefore induce T-cell responses with expanded breadth and may facilitate the development of effective T -cell-based HIV -1 vaccines.

  3. IL-15 transpresentation promotes both human T-cell reconstitution and T-cell-dependent antibody responses in vivo

    NARCIS (Netherlands)

    Huntington, Nicholas D.; Alves, Nuno L.; Legrand, Nicolas; Lim, Annick; Strick-Marchand, Helene; Mention, Jean-Jacques; Plet, Ariane; Weijer, Kees; Jacques, Yannick; Becker, Pablo D.; Guzman, Carlos; Soussan, Patrick; Kremsdorf, Dina; Spits, Hergen; Di Santo, James P.

    2011-01-01

    Cytokine immunotherapies targeting T lymphocytes are attractive clinical interventions against viruses and tumors. In the mouse, the homeostasis of memory α/β CD8(+) T cells and natural killer (NK) cells is significantly improved with increased IL-15 bioavailability. In contrast, the role of

  4. Tumor sialylation impedes T cell mediated anti-tumor responses while promoting tumor associated-regulatory T cells

    NARCIS (Netherlands)

    Perdicchio, Maurizio; Cornelissen, Lenneke A. M.; Streng-Ouwehand, Ingeborg; Engels, Steef; Verstege, Marleen I.; Boon, Louis; Geerts, Dirk; van Kooyk, Yvette; Unger, Wendy W. J.

    2016-01-01

    The increased presence of sialylated glycans on the tumor surface has been linked to poor prognosis, yet the effects on tumor-specific T cell immunity are hardly studied. We here show that hypersialylation of B16 melanoma substantially influences tumor growth by preventing the formation of effector

  5. Comparison of antigen-specific T-cell responses of tuberculosis patients using complex or single antigens of Mycobacterium tuberculosis

    DEFF Research Database (Denmark)

    Mustafa, A S; Amoudy, H A; Wiker, H G

    1998-01-01

    We have screened peripheral blood mononuclear cells (PBMC) from tuberculosis (TB) patients for proliferative reactivity and interferon-gamma (IFN-gamma) secretion against a panel of purified recombinant (r) and natural (n) culture filtrate (rESAT-6, nMPT59, nMPT64 and nMPB70) and somatic-derived (r......GroES, rPstS, rGroEL and rDnaK) antigens of Mycobacterium tuberculosis. The responses of PBMC to these defined antigens were compared with the corresponding results obtained with complex antigens, such as whole-cell M. tuberculosis, M. tuberculosis culture filtrate (MT-CF) and cell wall antigens, as well...... as the vaccine strain, Mycobacterium bovis bacillus Calmette-Guerin (BCG). In addition, M. tuberculosis and MT-CF-induced T-cell lines were tested in the same assays against the panel of purified and complex antigens. The compiled data from PBMC and T-cell lines tested for antigen-induced proliferation and IFN...

  6. Aging impairs recipient T cell intrinsic and extrinsic factors in response to transplantation.

    Directory of Open Access Journals (Sweden)

    Hua Shen

    Full Text Available As increasing numbers of older people are listed for solid organ transplantation, there is an urgent need to better understand how aging modifies alloimmune responses. Here, we investigated whether aging impairs the ability of donor dendritic cells or recipient immunity to prime alloimmune responses to organ transplantation.Using murine experimental models, we found that aging impaired the host environment to expand and activate antigen specific CD8(+ T cells. Additionally, aging impaired the ability of polyclonal T cells to induce acute allograft rejection. However, the alloimmune priming capability of donor dendritic cells was preserved with aging.Aging impairs recipient responses, both T cell intrinsic and extrinsic, in response to organ transplantation.

  7. Characterization of CD4 and CD8 T Cell Responses in MuSK Myasthenia Gravis

    Science.gov (United States)

    Yi, JS; Guidon, A; Sparks, S; Osborne, R; Juel, VC; Massey, JM; Sanders, DB; Weinhold, KJ; Guptill, JT

    2014-01-01

    Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T-cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T-cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T-cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T-cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T-cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T-cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in Treg function or number. PMID:24378287

  8. Response of Human T Cells to Tetanus Neurotoxin HCC Sub-Domain: T Cell Cytokine Production and Activation Marker Induced by HCC.

    Science.gov (United States)

    Ghafari-Khamene, Maryam; Torabi-Goudarzi, Saeedeh; Hosseini, Maryam; Haji-Fatahaliha, Mostafa; Sadreddini, Sanam; Seyfi-Najmi, Mehrnosh; Majidi, Jafar; Yousefi, Mehdi

    2015-10-01

    Tetanus is caused by the tetanus neurotoxin (TeNT), a 150 kDa single polypeptide molecule which is cleaved into active two-chain molecules composed of a 50 kDa N-terminal light (L) and a 100 kDa C-terminal heavy (H) chains. Fragment C is further subdivided into two subdomains: the proximal HCN  subdomain and the extreme carboxy subdomain, HCC. HCC is considered as an immunodominant part of TeNT and is responsible for TeNT binding activity to neurons.In the present study, we investigated the ability of recombinant HCC(r HCC) to induce T cell activation. Our results showed that recombinant HCC has a stimulatory effect on IFN-γ secretion by T cells after 48h co-incubation in the presence of anti-TLR-2 Ab. Also, Hcc can induce the expression of CD69 on T cells.Our finding indicated that stimulatory effects of HCC on T cells are TLR-2 independent and anti-TLR-2 inhibitory antibody fails to neutralize HCC stimulatory effects on T cells.Furthermore, HCC  is critical for immunogenic activity of TeNT and is able to induce T cells through TLR-2 independent pathway.

  9. [T cell-mediated immune responses and the recognition of tuberculosis antigens].

    Science.gov (United States)

    Tsujimura, Kunio; Koide, Yukio

    2010-06-01

    T cell-mediated immune responses profoundly contribute to the protection against the re-activation of latently infected Mycobacterium tuberculosis. Th1 cells produce IFN-gamma to activate infected macrophages and promote the formation of granulomas around infected macrophages. CD8+, gamma delta and CD1-restricted T cells also produce IFN-gamma and participate the protective responses against bacterial growth. Th17 cells produce IL-17 to promote the mobilization of immunocompetent cells and contribute to the granuloma formation. On the contrary, Th2 cells and Tregs interfere these protective immune responses.

  10. Primed T cell responses to chemokines are regulated by the immunoglobulin-like molecule CD31.

    Directory of Open Access Journals (Sweden)

    Madhav Kishore

    Full Text Available CD31, an immunoglobulin-like molecule expressed by leukocytes and endothelial cells, is thought to contribute to the physiological regulation T cell homeostasis due to the presence of two immunotyrosine-based inhibitory motifs in its cytoplasmic tail. Indeed, loss of CD31 expression leads to uncontrolled T cell-mediated inflammation in a variety of experimental models of disease and certain CD31 polymorphisms correlate with increased disease severity in human graft-versus-host disease and atherosclerosis. The molecular mechanisms underlying CD31-mediated regulation of T cell responses have not yet been clarified. We here show that CD31-mediated signals attenuate T cell chemokinesis both in vitro and in vivo. This effect selectively affects activated/memory T lymphocytes, in which CD31 is clustered on the cell membrane where it segregates to the leading edge. We provide evidence that this molecular segregation, which does not occur in naïve T lymphocytes, might lead to cis-CD31 engagement on the same membrane and subsequent interference with the chemokine-induced PI3K/Akt signalling pathway. We propose that CD31-mediated modulation of memory T cell chemokinesis is a key mechanism by which this molecule contributes to the homeostatic regulation of effector T cell immunity.

  11. Nasopharyngeal infection by Streptococcus pyogenes requires superantigen-responsive Vβ-specific T cells

    Science.gov (United States)

    Zeppa, Joseph J.; Kasper, Katherine J.; Mohorovic, Ivor; Mazzuca, Delfina M.

    2017-01-01

    The globally prominent pathogen Streptococcus pyogenes secretes potent immunomodulatory proteins known as superantigens (SAgs), which engage lateral surfaces of major histocompatibility class II molecules and T-cell receptor (TCR) β-chain variable domains (Vβs). These interactions result in the activation of numerous Vβ-specific T cells, which is the defining activity of a SAg. Although streptococcal SAgs are known virulence factors in scarlet fever and toxic shock syndrome, mechanisms by how SAgs contribute to the life cycle of S. pyogenes remain poorly understood. Herein, we demonstrate that passive immunization against the Vβ8-targeting SAg streptococcal pyrogenic exotoxin A (SpeA), or active immunization with either wild-type or a nonfunctional SpeA mutant, protects mice from nasopharyngeal infection; however, only passive immunization, or vaccination with inactive SpeA, resulted in high-titer SpeA-specific antibodies in vivo. Mice vaccinated with wild-type SpeA rendered Vβ8+ T cells poorly responsive, which prevented infection. This phenotype was reproduced with staphylococcal enterotoxin B, a heterologous SAg that also targets Vβ8+ T cells, and rendered mice resistant to infection. Furthermore, antibody-mediated depletion of T cells prevented nasopharyngeal infection by S. pyogenes, but not by Streptococcus pneumoniae, a bacterium that does not produce SAgs. Remarkably, these observations suggest that S. pyogenes uses SAgs to manipulate Vβ-specific T cells to establish nasopharyngeal infection. PMID:28794279

  12. Cytotoxic T cell responses to Streptococcus are associated with improved prognosis of oral squamous cell carcinoma.

    Science.gov (United States)

    Wang, Jie; Sun, Feng; Lin, Xiaoyu; Li, Zaiye; Mao, Xiaohe; Jiang, Canhua

    2018-01-01

    Several species of Streptococcus, such as S. salivarius, S. mitis, and S. anginosus, are found to extensively colonize the oral cavity and the upper respiratory tract, and have been shown to increase in patients with oral squamous cell carcinoma (OSCC). Accumulating evidence have revealed that commensal bacteria are involved in antitumor immunity via T cell-mediated mechanisms, but the role of Streptococcus enrichment in OSCC is yet unclear. In this study, we stimulated peripheral blood mononuclear cells from non-cancer controls (NCs) and OSCC patients with S. salivarius, S. mitis, and S. anginosus. We observed that compared to NC subjects, OSCC patients at earlier stages had higher frequencies of granzyme B-expressing CD8 T cells for all Streptococcus species tested, while OSCC patients at more advanced stages had higher frequencies of granzyme B-expressing CD8 T cells for S. anginosus but not other Streptococcus species. In OSCC patients, the Streptococcus-reactive CD8 T cells presented significantly lower levels of PD-1 and TIM-3 expression than Streptococcus-nonreactive CD8 T cells. The clinical outcomes of OSCC patients in our cohort were tracked for 24 months after the resection of the primary tumor. In patients that did not present tumor recurrence, the frequencies of S. salivarius-reactive and S. mitis-reactive CD8 T cells were significantly higher than that in patients that developed recurrent tumor. Furthermore, in patients with tumor recurrence, the duration between primary tumor resection and tumor recurrence was positively associated with the frequencies of S. salivarius-reactive and S. anginosus-reactive CD8 T cells. Together, we demonstrated that Streptococcus-reactive CD8 T cell responses might contribute to antitumor immunity in OSCC patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. CIP2A Promotes T-Cell Activation and Immune Response to Listeria monocytogenes Infection.

    Directory of Open Access Journals (Sweden)

    Christophe Côme

    Full Text Available The oncoprotein Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A is overexpressed in most malignancies and is an obvious candidate target protein for future cancer therapies. However, the physiological importance of CIP2A-mediated PP2A inhibition is largely unknown. As PP2A regulates immune responses, we investigated the role of CIP2A in normal immune system development and during immune response in vivo. We show that CIP2A-deficient mice (CIP2AHOZ present a normal immune system development and function in unchallenged conditions. However when challenged with Listeria monocytogenes, CIP2AHOZ mice display an impaired adaptive immune response that is combined with decreased frequency of both CD4+ T-cells and CD8+ effector T-cells. Importantly, the cell autonomous effect of CIP2A deficiency for T-cell activation was confirmed. Induction of CIP2A expression during T-cell activation was dependent on Zap70 activity. Thus, we reveal CIP2A as a hitherto unrecognized mediator of T-cell activation during adaptive immune response. These results also reveal CIP2AHOZ as a possible novel mouse model for studying the role of PP2A activity in immune regulation. On the other hand, the results also indicate that CIP2A targeting cancer therapies would not cause serious immunological side-effects.

  14. 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

    DEFF Research Database (Denmark)

    Steffensen, Maria A; Pedersen, Louise Holm; Jahn, Marie Louise

    2016-01-01

    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......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...

  15. Allergen and Epitope Targets of Mouse-Specific T Cell Responses in Allergy and Asthma

    Directory of Open Access Journals (Sweden)

    Véronique Schulten

    2018-02-01

    Full Text Available Mouse allergy has become increasingly common, mainly affecting laboratory workers and inner-city households. To date, only one major allergen, namely Mus m 1, has been described. We sought to identify T cell targets in mouse allergic patients. PBMC from allergic donors were expanded with either murine urine or epithelial extract and subsequently screened for cytokine production (IL-5 and IFNγ in response to overlapping peptides spanning the entire Mus m 1 sequence, peptides from various Mus m 1 isoforms [major urinary proteins (MUPs], peptides from mouse orthologs of known allergens from other mammalian species and peptides from proteins identified by immunoproteomic analysis of IgE/IgG immunoblots of mouse urine and epithelial extracts. This approach let to the identification of 106 non-redundant T cell epitopes derived from 35 antigens. Three major T cell-activating regions were defined in Mus m 1 alone. Moreover, our data show that immunodominant epitopes were largely shared between Mus m 1 and other MUPs even from different species, suggesting that sequence conservation in different allergens is a determinant for immunodominance. We further identified several novel mouse T cell antigens based on their homology to known mammalian allergens. Analysis of cohort-specific T cell responses revealed that rhinitis and asthmatic patients recognized different epitope repertoires. Epitopes defined herein can be formulated into an epitope “megapool” used to diagnose mouse allergy and study mouse-specific T cell responses directly ex vivo. This analysis of T cell epitopes provides a good basis for future studies to increase our understanding of the immunopathology associated with MO-allergy and asthma.

  16. The histone deacetylase inhibitor Trichostatin A modulates CD4+ T cell responses

    Directory of Open Access Journals (Sweden)

    Moreira José

    2003-11-01

    Full Text Available Abstract Background Histone deacetylase inhibitors (HDACIs induce hyperacetylation of core histones modulating chromatin structure and affecting gene expression. These compounds are also able to induce growth arrest, cell differentiation, and apoptotic cell death of tumor cells in vitro as well as in vivo. Even though several genes modulated by HDAC inhibition have been identified, those genes clearly responsible for the biological effects of these drugs have remained elusive. We investigated the pharmacological effect of the HDACI and potential anti-cancer agent Trichostatin A (TSA on primary T cells. Methods To ascertain the effect of TSA on resting and activated T cells we used a model system where an enriched cell population consisting of primary T-cells was stimulated in vitro with immobilized anti-CD3/anti-CD28 antibodies whilst exposed to pharmacological concentrations of Trichostatin A. Results We found that this drug causes a rapid decline in cytokine expression, accumulation of cells in the G1 phase of the cell cycle, and induces apoptotic cell death. The mitochondrial respiratory chain (MRC plays a critical role in the apoptotic response to TSA, as dissipation of mitochondrial membrane potential and reactive oxygen species (ROS scavengers block TSA-induced T-cell death. Treatment of T cells with TSA results in the altered expression of a subset of genes involved in T cell responses, as assessed by microarray gene expression profiling. We also observed up- as well as down-regulation of various costimulatory/adhesion molecules, such as CD28 and CD154, important for T-cell function. Conclusions Taken together, our findings indicate that HDAC inhibitors have an immunomodulatory potential that may contribute to the potency and specificity of these antineoplastic compounds and might be useful in the treatment of autoimmune disorders.

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

    Directory of Open Access Journals (Sweden)

    Shayla K Shorter

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

  18. Human T cell responses to Dengue and Zika virus infection compared to Dengue/Zika coinfection.

    Science.gov (United States)

    Badolato-Corrêa, Jessica; Sánchez-Arcila, Juan Camilo; Alves de Souza, Thiara Manuele; Santos Barbosa, Luciana; Conrado Guerra Nunes, Priscila; da Rocha Queiroz Lima, Monique; Gandini, Mariana; Bispo de Filippis, Ana Maria; Venâncio da Cunha, Rivaldo; Leal de Azeredo, Elzinandes; de-Oliveira-Pinto, Luzia Maria

    2017-12-28

    Zika virus (ZIKV) and dengue virus (DENV) co-circulated during latest outbreaks in Brazil, hence, it is important to evaluate the host cross-reactive immune responses to these viruses. So far, little is known about human T cell responses to ZIKV and no reports detail adaptive immune responses during DENV/ZIKV coinfection. Here, we studied T cells responses in well-characterized groups of DENV, ZIKV, or DENV/ZIKV infected patients and DENV-exposed healthy donors. We evaluated chemokine receptors expression and single/multifunctional frequencies of IFNγ, TNF, and IL2-producing T cells during these infections. Even without antigenic stimulation, it was possible to detect chemokine receptors and IFNγ, TNF, and IL2-producing T cells from all individuals by flow cytometry. Additionally, PBMCs' IFNγ response to DENV NS1 protein and to polyclonal stimuli was evaluated by ELISPOT. DENV and ZIKV infections and DENV/ZIKV coinfections similarly induced expression of CCR5, CX3CR1, and CXCR3 on CD4 and CD8 T cells. DENV/ZIKV coinfection decreased the ability of CD4 + T cells to produce IFNγ + , TNF + , TNF  +  IFNγ + , and TNF  +  IL2 + , compared to DENV and ZIKV infections. A higher magnitude of IFNγ response to DENV NS1 was found in donors with a history of dengue infection, however, a hyporesponsiveness was found in acute DENV, ZIKV, or DENV/ZIKV infected patients, even previously infected with DENV. Therefore, we emphasize the potential impact of coinfection on the immune response from human hosts, mainly in areas where DENV and ZIKV cocirculate. © 2017 The Authors. Immunity, Inflammation and Disease Published by John Wiley & Sons Ltd.

  19. Vitamin D-binding protein controls T cell responses to vitamin D

    DEFF Research Database (Denmark)

    Kongsbak, Martin; von Essen, Marina Rode; Levring, Trine Bøegh

    2014-01-01

    BACKGROUND: In vitro studies have shown that the active form of vitamin D3, 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3), can regulate differentiation of CD4+ T cells by inhibiting Th1 and Th17 cell differentiation and promoting Th2 and Treg cell differentiation. However, the serum concentration of 1...... that activated T cells express the 25(OH)D-1α-hydroxylase CYP27B1 that converts 25(OH)D3 to 1,25(OH)2D3, it is still controversial whether activated T cells have the capacity to produce sufficient amounts of 1,25(OH)2D3 to affect vitamin D-responsive genes. Furthermore, it is not known how the vitamin D......-binding protein (DBP) found in high concentrations in serum affects T cell responses to 25(OH)D3. RESULTS: We found that activated T cells express CYP27B1 and have the capacity to produce sufficient 1,25(OH)2D3 to affect vitamin D-responsive genes when cultured with physiological concentrations of 25(OH)D3...

  20. Effector, Memory, and Dysfunctional CD8+ T Cell Fates in the Antitumor Immune Response

    Science.gov (United States)

    2016-01-01

    The adaptive immune system plays a pivotal role in the host's ability to mount an effective, antigen-specific immune response against tumors. CD8+ tumor-infiltrating lymphocytes (TILs) mediate tumor rejection through recognition of tumor antigens and direct killing of transformed cells. In growing tumors, TILs are often functionally impaired as a result of interaction with, or signals from, transformed cells and the tumor microenvironment. These interactions and signals can lead to transcriptional, functional, and phenotypic changes in TILs that diminish the host's ability to eradicate the tumor. In addition to effector and memory CD8+ T cells, populations described as exhausted, anergic, senescent, and regulatory CD8+ T cells have been observed in clinical and basic studies of antitumor immune responses. In the context of antitumor immunity, these CD8+ T cell subsets remain poorly characterized in terms of fate-specific biomarkers and transcription factor profiles. Here we discuss the current characterization of CD8+ T cell fates in antitumor immune responses and discuss recent insights into how signals in the tumor microenvironment influence TIL transcriptional networks to promote CD8+ T cell dysfunction. PMID:27314056

  1. Human T cell responses to the ESAT-6 antigen from Mycobacterium tuberculosis

    DEFF Research Database (Denmark)

    Ravn, P; Demissie, A; Eguale, T

    1999-01-01

    Human T cell responses to ESAT-6 and eight synthetic overlapping peptides were investigated in tuberculosis (TB) patients and control subjects from regions of high and low endemicity for TB. ESAT-6 was recognized by 65% of all tuberculin purified protein derivative-responsive TB patients, whereas...

  2. Human T cell responses induced by vaccination with Mycobacterium bovis bacillus Calmette-Guérin

    DEFF Research Database (Denmark)

    Ravn, P; Boesen, H; Pedersen, B K

    1997-01-01

    as a CD4 response with a Th1-like cytokine pattern and substantial levels of Ag-specific cytotoxicity. The specificity of the T cell response generated was broad and directed to a range of culture filtrate Ag fractions. The study shows that BCG vaccination of previously nonsensitized donors can provide...

  3. Amino acid substitutions in the melanoma antigen recognized by T cell 1 peptide modulate cytokine responses in melanoma-specific T cells

    DEFF Research Database (Denmark)

    Nielsen, M B; Kirkin, A F; Loftus, D

    2000-01-01

    enhances the production of mRNA for interleukin (IL)-5, IL-10, IL-13, IL-15, and interferon-gamma and significantly enhances release of IL-13 and IL-10 from anti-MART-1 cytotoxic T cells. Another heteroclitic peptide, 1L, with an A to L substitution in MART-1(27-35), also enhances the tyrosine...... phosphorylation response in anti-MART-1 cytotoxic CD8+ T cells. Yet, 1L does not enhance the production of T helper cell type 2-like cytokines (IL-10 and IL-13). Together these data show that minor amino acid modifications of immunodominant melanoma peptides profoundly influence the cytokine response in melanoma...

  4. Distribution of T Cells in Rainbow Trout (Oncorhynchus mykiss) Skin and Responsiveness to Viral Infection

    Science.gov (United States)

    Leal, Esther; Granja, Aitor G.; Zarza, Carlos; Tafalla, Carolina

    2016-01-01

    Although the skin constitutes the first line of defense against waterborne pathogens, there is a great lack of information regarding the skin associated lymphoid tissue (SALT) and whether immune components of the skin are homogeneously distributed through the surface of the fish is still unknown. In the current work, we have analyzed the transcription of several immune genes throughout different rainbow trout (Oncorhynchus mykiss) skin areas. We found that immunoglobulin and chemokine gene transcription levels were higher in a skin area close to the gills. Furthermore, this skin area as well as other anterior sections also transcribed significantly higher levels of many different immune genes related to T cell immunity such as T cell receptor α (TCRα), TCRγ, CD3, CD4, CD8, perforin, GATA3, Tbet, FoxP3, interferon γ (IFNγ), CD40L and Eomes in comparison to posterior skin sections. In agreement with these results, immunohistochemical analysis revealed that anterior skin areas had a higher concentration of CD3+ T cells and flow cytometry analysis confirmed that the percentage of CD8+ T lymphocytes was also higher in anterior skin sections. These results demonstrate for the first time that T cells are not homogeneously distributed throughout the teleost skin. Additionally, we studied the transcriptional regulation of these and additional T cell markers in response to a bath infection with viral hemorrhagic septicemia virus (VHSV). We found that VHSV regulated the transcription of several of these T cell markers in both the skin and the spleen; with some differences between anterior and posterior skin sections. Altogether, our results point to skin T cells as major players of teleost skin immunity in response to waterborne viral infections. PMID:26808410

  5. Human Memory CD4+ T Cell Immune Responses against Giardia lamblia

    Science.gov (United States)

    Sørnes, Steinar; Peirasmaki, Dimitra; Svärd, Staffan; Langeland, Nina

    2015-01-01

    The intestinal protozoan parasite Giardia lamblia may cause severe prolonged diarrheal disease or pass unnoticed as an asymptomatic infection. T cells seem to play an important role in the immune response to Giardia infection, and memory responses may last years. Recently, TH17 responses have been found in three animal studies of Giardia infection. The aim of this study was to characterize the human CD4+ T cell responses to Giardia. Peripheral blood mononuclear cells (PBMCs) were obtained from 21 returning travelers with recent or ongoing giardiasis and 12 low-risk healthy controls and stimulated in vitro with Giardia lamblia proteins. Production of tumor necrosis factor alpha (TNF-α), gamma interferon, interleukin-17A (IL-17A), IL-10, and IL-4 was measured in CD4+ effector memory (EM) T cells after 24 h by flow cytometry. After 6 days of culture, activation and proliferation were measured by flow cytometry, while an array of inflammatory cytokine levels in supernatants were measured with multiplex assays. We found the number of IL-17A-producing CD4+ EM T cells, as well as that of cells simultaneously producing both IL-17A and TNF-α, to be significantly elevated in the Giardia-exposed individuals after 24 h of antigen stimulation. In supernatants of PBMCs stimulated with Giardia antigens for 6 days, we found inflammation-associated cytokines, including 1L-17A, as well as CD4+ T cell activation and proliferation, to be significantly elevated in the Giardia-exposed individuals. We conclude that symptomatic Giardia infection in humans induces a CD4+ EM T cell response of which IL-17A production seems to be an important component. PMID:26376930

  6. Norovirus-specific memory T cell responses in adult human donors

    Directory of Open Access Journals (Sweden)

    Maria Malm

    2016-10-01

    Full Text Available Norovirus (NoV is a leading cause of acute gastroenteritis in people of all ages worldwide. NoV specific serum antibodies which block the binding of NoV virus-like particles (VLPs to the cell receptors have been thoroughly investigated. In contrast, only a few publications are available on the NoV capsid VP1 protein-specific T cell responses in humans naturally infected with the virus. Freshly isolated peripheral blood mononuclear cells of eight healthy adult human donors previously exposed to NoV were stimulated with purified VLPs derived from NoV GII.4-1999, GII.4-2012 (Sydney, and GI.3, and IFN-g production was measured by an ELISPOT assay. In addition, 76 overlapping synthetic peptides spanning the entire 539 amino acid sequence of GII.4 VP1 were pooled into two-dimensional matrices and used to identify putative T cell epitopes. Seven of the eight subjects produced IFN-g in response to the peptides and five subjects produced IFN-g in response to the VLPs of the same origin. In general, stronger T cell responses were induced with the peptides in each donor compared to the VLPs. A CD8+ T cell epitope in the shell domain of the VP1 (134SPSQVTMFPHIIVDVRQL151 was identified in two subjects, both having human leukocyte antigen (HLA-A*02:01 allele. To our knowledge, this is the first report using synthetic peptides to study NoV-specific T cell responses in human subjects and identify T cell epitopes.

  7. Altered T-cell responses by the periodontal pathogen Porphyromonas gingivalis.

    Directory of Open Access Journals (Sweden)

    Hazem Khalaf

    Full Text Available Several studies support an association between the chronic inflammatory diseases periodontitis and atherosclerosis with a crucial role for the periodontal pathogen Porphyromonas gingivalis. However, the interplay between this pathogen and the adaptive immune system, including T-cells, is sparsely investigated. Here we used Jurkat T-cells to determine the effects of P. gingivalis on T-cell-mediated adaptive immune responses. We show that viable P. gingivalis targets IL-2 expression at the protein level. Initial cellular events, including ROS production and [Ca(2+](i, were elevated in response to P. gingivalis, but AP-1 and NF-κB activity dropped below basal levels and T-cells were unable to sustain stable IL-2 accumulation. IL-2 was partially restored by Leupeptin, but not by Cathepsin B Inhibitor, indicating an involvement of Rgp proteinases in the suppression of IL-2 accumulation. This was further confirmed by purified Rgp that caused a dose-dependent decrease in IL-2 levels. These results provide new insights of how this periodontal pathogen evades the host adaptive immune system by inhibiting IL-2 accumulation and thus attenuating T-cell proliferation and cellular communication.

  8. Cross-reactive microbial peptides can modulate HIV-specific CD8+ T cell responses.

    Directory of Open Access Journals (Sweden)

    Christopher W Pohlmeyer

    Full Text Available Heterologous immunity is an important aspect of the adaptive immune response. We hypothesized that this process could modulate the HIV-1-specific CD8+ T cell response, which has been shown to play an important role in HIV-1 immunity and control. We found that stimulation of peripheral blood mononuclear cells (PBMCs from HIV-1-positive subjects with microbial peptides that were cross-reactive with immunodominant HIV-1 epitopes resulted in dramatic expansion of HIV-1-specific CD8+ T cells. Interestingly, the TCR repertoire of HIV-1-specific CD8+ T cells generated by ex vivo stimulation of PBMCs using HIV-1 peptide was different from that of cells stimulated with cross-reactive microbial peptides in some HIV-1-positive subjects. Despite these differences, CD8+ T cells stimulated with either HIV-1 or cross-reactive peptides effectively suppressed HIV-1 replication in autologous CD4+ T cells. These data suggest that exposure to cross-reactive microbial antigens can modulate HIV-1-specific immunity.

  9. Otud7b facilitates T cell activation and inflammatory responses by regulating Zap70 ubiquitination.

    Science.gov (United States)

    Hu, Hongbo; Wang, Hui; Xiao, Yichuan; Jin, Jin; Chang, Jae-Hoon; Zou, Qiang; Xie, Xiaoping; Cheng, Xuhong; Sun, Shao-Cong

    2016-03-07

    Signal transduction from the T cell receptor (TCR) is crucial for T cell-mediated immune responses and, when deregulated, also contributes to the development of autoimmunity. How TCR signaling is regulated is incompletely understood. In this study, we demonstrate a ubiquitin-dependent mechanism in which the deubiquitinase Otud7b has a crucial role in facilitating TCR signaling. Upon TCR ligation, Otud7b is rapidly recruited to the tyrosine kinase Zap70, a central mediator of TCR-proximal signaling. Otud7b deficiency attenuates the activation of Zap70 and its downstream pathways and impairs T cell activation and differentiation, rendering mice refractory to T cell-mediated autoimmune and inflammatory responses. Otud7b facilitated Zap70 activation by deubiquitinating Zap70, thus preventing the association of Zap70 with the negative-regulatory phosphatases Sts1 and Sts2. These findings establish Otud7b as a positive regulator of TCR-proximal signaling and T cell activation, highlighting the importance of deubiquitination in regulating Zap70 function. © 2016 Sun et al.

  10. Human CD4+ T cell responses to the dog major allergen Can f 1 and its human homologue tear lipocalin resemble each other.

    Directory of Open Access Journals (Sweden)

    Aino L K Liukko

    Full Text Available Lipocalin allergens form a notable group of proteins, as they contain most of the significant respiratory allergens from mammals. The basis for the allergenic capacity of allergens in the lipocalin family, that is, the development of T-helper type 2 immunity against them, is still unresolved. As immunogenicity has been proposed to be a decisive feature of allergens, the purpose of this work was to examine human CD4+ T cell responses to the major dog allergen Can f 1 and to compare them with those to its human homologue, tear lipocalin (TL. For this, specific T cell lines were induced in vitro from the peripheral blood mononuclear cells of Can f 1-allergic and healthy dog dust-exposed subjects with peptides containing the immunodominant T cell epitopes of Can f 1 and the corresponding TL peptides. We found that the frequency of Can f 1 and TL-specific T cells in both subject groups was low and close to each other, the difference being about two-fold. Importantly, we found that the proliferative responses of both Can f 1 and TL-specific T cell lines from allergic subjects were stronger than those from healthy subjects, but that the strength of the responses within the subject groups did not differ between these two antigens. Moreover, the phenotype of the Can f 1 and TL-specific T cell lines, determined by cytokine production and expression of cell surface markers, resembled each other. The HLA system appeared to have a minimal role in explaining the allergenicity of Can f 1, as the allergic and healthy subjects' HLA background did not differ, and HLA binding was very similar between Can f 1 and TL peptides. Along with existing data on lipocalin allergens, we conclude that strong antigenicity is not decisive for the allergenicity of Can f 1.

  11. Aberrantly Expressed Long Non-Coding RNAs In CD8+T Cells Response to Active Tuberculosis.

    Science.gov (United States)

    Fu, Yurong; Gao, Kunshan; Tao, Enxue; Li, Ruifang; Yi, Zhengjun

    2017-12-01

    Dysregulated expression of long noncoding RNAs (lncRNAs) has been demonstrated as being implicated in a variety of human diseases. In the study we aimed to determine lncRNA profile in CD8 + T cells response to active tuberculosis (TB). We examined the lncRNA expression by microarray in circulating CD8 + T cells isolated from patients with active TB and healthy controls. Change predictions to analysis was used to address functional roles of the deregulated mRNAs. Real-time quantitative PCR (RT-qPCR) was used to validate the microarray result. In total, 328 lncRNAs and 356 mRNAs were differentially expressed in TB CD8 + T cells. Upregulated mRNAs were mainly enriched in cAMP signaling pathway, calcium signaling pathway, and TGF-beta signaling pathway, while downregulated mRNAs were enriched in antigen processing and presentation and natural killer cell mediated cytotoxicity in TB CD8 + T cells. Interestingly, we found that heme oxygenase 1 (HMOX1) was decreased in active TB CD8 + T cells, while its nearby lincRNA XLOC_014219 was upregulated. Subsequent RT-qPCR results confirmed the changes. This is the first research addressing lncRNA expression profiles in active TB CD8 + T cells. The aberrantly expressed lncRNAs observed in the study may provide clues to the dysfunction of CD8 + T cells and so to the pathophysiological properties of active TB. Further studies should focus on the function of lncRNAs involved in active TB. J. Cell. Biochem. 118: 4275-4284, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  12. Myeloid Dendritic Cells (DCs) of Mice Susceptible to Paracoccidioidomycosis Suppress T Cell Responses whereas Myeloid and Plasmacytoid DCs from Resistant Mice Induce Effector and Regulatory T Cells

    Science.gov (United States)

    Pina, Adriana; Frank de Araujo, Eliseu; Felonato, Maíra; Loures, Flávio V.; Feriotti, Claudia; Bernardino, Simone; Barbuto, José Alexandre M.

    2013-01-01

    The protective adaptive immune response in paracoccidioidomycosis, a mycosis endemic among humans, is mediated by T cell immunity, whereas impaired T cell responses are associated with severe, progressive disease. The early host response to Paracoccidioides brasiliensis infection is not known since the disease is diagnosed at later phases of infection. Our laboratory established a murine model of infection where susceptible mice reproduce the severe disease, while resistant mice develop a mild infection. This work aimed to characterize the influence of dendritic cells in the innate and adaptive immunity of susceptible and resistant mice. We verified that P. brasiliensis infection induced in bone marrow-derived dendritic cells (DCs) of susceptible mice a prevalent proinflammatory myeloid phenotype that secreted high levels of interleukin-12 (IL-12), tumor necrosis factor alpha, and IL-β, whereas in resistant mice, a mixed population of myeloid and plasmacytoid DCs secreting proinflammatory cytokines and expressing elevated levels of secreted and membrane-bound transforming growth factor β was observed. In proliferation assays, the proinflammatory DCs from B10.A mice induced anergy of naïve T cells, whereas the mixed DC subsets from resistant mice induced the concomitant proliferation of effector and regulatory T cells (Tregs). Equivalent results were observed during pulmonary infection. The susceptible mice displayed preferential expansion of proinflammatory myeloid DCs, resulting in impaired proliferation of effector T cells. Conversely, the resistant mice developed myeloid and plasmacytoid DCs that efficiently expanded gamma interferon-, IL-4-, and IL-17-positive effector T cells associated with increased development of Tregs. Our work highlights the deleterious effect of excessive innate proinflammatory reactions and provides new evidence for the importance of immunomodulation during pulmonary paracoccidioidomycosis. PMID:23340311

  13. CD8+ T-cell response against MUC1-derived peptides in gastrointestinal cancer survivors.

    Science.gov (United States)

    Dittmann, Jasmin; Keller-Matschke, Karin; Weinschenk, Toni; Kratt, Thomas; Heck, Tobias; Becker, Horst-Dieter; Stevanović, Stefan; Rammensee, Hans-Georg; Gouttefangeas, Cécile

    2005-08-01

    The tumor-associated antigens CEA, MUC1 and Her2/neu are broadly expressed in gastrointestinal tumors, and are attractive candidates for targeting by T-cell-based immunotherapy. However, little is known about the natural cytotoxic T-cell response of patients suffering from colorectal or gastric carcinoma against these three as well as other antigens. Using a quantitative reverse transcription-polymerase chain reaction-based assay for IFN-gamma, we analyzed the CD8+ T-cell repertoire present in the blood of HLA-A2+ gastrointestinal tumor survivors against five known epitopes derived from CEA, MUC1 and Her2/neu. The results show that most of the patients (16 from 22 tested) have detectable, peripheral CD8+ T cells directed against at least one of these three proteins. Interestingly, the majority of these patients reacts to the two MUC1-derived HLA-A*0201 epitopes tested (14 from 16), demonstrating that this protein represents one dominant target for CD8+ T cells in gastrointestinal cancer.

  14. Parallel detection of antigen-specific T cell responses by combinatorial encoding of MHC multimers

    DEFF Research Database (Denmark)

    Andersen, Rikke Sick; Kvistborg, Pia; Frøsig, Thomas Mørch

    2012-01-01

    Fluorescently labeled multimeric complexes of peptide-MHC, the molecular entities recognized by the T cell receptor, have become essential reagents for detection of antigen-specific CD8(+) T cells by flow cytometry. Here we present a method for high-throughput parallel detection of antigen-specif......(+) immune responses during cancer and infectious disease or after immunotherapy. One panel of 28 combinatorially encoded MHC multimers can be prepared in 4 h. Staining and detection takes a further 3 h.......Fluorescently labeled multimeric complexes of peptide-MHC, the molecular entities recognized by the T cell receptor, have become essential reagents for detection of antigen-specific CD8(+) T cells by flow cytometry. Here we present a method for high-throughput parallel detection of antigen......-specific T cells by combinatorial encoding of MHC multimers. Peptide-MHC complexes are produced by UV-mediated MHC peptide exchange and multimerized in the form of streptavidin-fluorochrome conjugates. Eight different fluorochromes are used for the generation of MHC multimers and, by a two...

  15. The phosphorylation state of CD3gamma influences T cell responsiveness and controls T cell receptor cycling

    DEFF Research Database (Denmark)

    Dietrich, J; Backstrom, T; Lauritsen, JP

    1998-01-01

    mediated by the serine/threonine protein phosphatase-2A, but independent on microtubules or actin polymerization. Furthermore, in contrast to ligand-mediated TCR sorting, recycling of the TCR was independent of the tyrosine phosphatase CD45 and the Src tyrosine kinases p56(Lck) and p59(Fyn). Studies......The T cell receptor (TCR) is internalized following activation of protein kinase C (PKC) via a leucine (Leu)-based motif in CD3gamma. Some studies have indicated that the TCR is recycled back to the cell surface following PKC-mediated internalization. The functional state of recycled TCR...

  16. Characterization of Human CD8 T Cell Responses in Dengue Virus-Infected Patients from India.

    Science.gov (United States)

    Chandele, Anmol; Sewatanon, Jaturong; Gunisetty, Sivaram; Singla, Mohit; Onlamoon, Nattawat; Akondy, Rama S; Kissick, Haydn Thomas; Nayak, Kaustuv; Reddy, Elluri Seetharami; Kalam, Haroon; Kumar, Dhiraj; Verma, Anil; Panda, HareKrushna; Wang, Siyu; Angkasekwinai, Nasikarn; Pattanapanyasat, Kovit; Chokephaibulkit, Kulkanya; Medigeshi, Guruprasad R; Lodha, Rakesh; Kabra, Sushil; Ahmed, Rafi; Murali-Krishna, Kaja

    2016-12-15

    Epidemiological studies suggest that India has the largest number of dengue virus infection cases worldwide. However, there is minimal information about the immunological responses in these patients. CD8 T cells are important in dengue, because they have been implicated in both protection and immunopathology. Here, we provide a detailed analysis of HLA-DR + CD38 + and HLA-DR - CD38 + effector CD8 T cell subsets in dengue patients from India and Thailand. Both CD8 T cell subsets expanded and expressed markers indicative of antigen-driven proliferation, tissue homing, and cytotoxic effector functions, with the HLA-DR + CD38 + subset being the most striking in these effector qualities. The breadth of the dengue-specific CD8 T cell response was diverse, with NS3-specific cells being the most dominant. Interestingly, only a small fraction of these activated effector CD8 T cells produced gamma interferon (IFN-γ) when stimulated with dengue virus peptide pools. Transcriptomics revealed downregulation of key molecules involved in T cell receptor (TCR) signaling. Consistent with this, the majority of these CD8 T cells remained IFN-γ unresponsive even after TCR-dependent polyclonal stimulation (anti-CD3 plus anti-CD28) but produced IFN-γ by TCR-independent polyclonal stimulation (phorbol 12-myristate 13-acetate [PMA] plus ionomycin). Thus, the vast majority of these proliferating, highly differentiated effector CD8 T cells probably acquire TCR refractoriness at the time the patient is experiencing febrile illness that leads to IFN-γ unresponsiveness. Our studies open novel avenues for understanding the mechanisms that fine-tune the balance between CD8 T cell-mediated protective versus pathological effects in dengue. Dengue is becoming a global public health concern. Although CD8 T cells have been implicated both in protection and in the cytokine-mediated immunopathology of dengue, how the balance is maintained between these opposing functions remains unknown. We

  17. CD8(+) T Cells Produce the Chemokine CXCL10 in Response to CD27/CD70 Costimulation To Promote Generation of the CD8(+) Effector T Cell Pool

    NARCIS (Netherlands)

    Peperzak, Victor; Veraar, Elise A. M.; Xiao, Yanling; Babala, Nikolina; Thiadens, Klaske; Brugmans, Marieke; Borst, Jannie

    2013-01-01

    Various cell types can produce the chemokine CXCL10 in response to IFN-gamma stimulation. CXCL10 is generally viewed as a proinflammatory chemokine that promotes recruitment of CD8(+) and Th1-type CD4(+) effector T cells to infected or inflamed nonlymphoid tissues. We show that CXCL10 plays a role

  18. Responses of single germinal-center B cells in T-cell-dependent microculture.

    Science.gov (United States)

    George, A; Cebra, J J

    1991-01-01

    B cells purified from the germinal centers (GCs) of murine Peyer's patches can be stimulated in a clonal microculture containing helper T cells and dendritic cells to divide and secrete immunoglobulin. Intraclonal isotype switching occurs, and a variety of immunoglobulin isotypes, including IgA, is secreted. Memory cells, which generate clones secreting IgA exclusively, are only rarely identified in the GC B-cell subset. Such memory cells can, however, be readily identified among unfractionated Peyer's patch B cells, and in non-GC subsets of B cells. The results suggest that the GC does not contain IgA memory cells that can be restimulated in vitro to secrete only IgA. When division of GC B cells is prevented by irradiation or aphidicholin treatment, a large subset that secretes IgA as the sole immunoglobulin isotype is seen, and the output of presumably single B cells is large enough to be scored by RIA. Both helper T cells and dendritic cells are required for the phenomenon. The data indicate that commitment to IgA secretion occurs in Peyer's patch GCs and suggest that the prolific cell division known to be supported in GCs may forestall terminal differentiation of preplasmablasts to immunoglobulin secretion.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ryan D Pardy

    2017-02-01

    Full Text Available 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.

  1. Subclinical doses of the nerve gas sarin impair T cell responses through the autonomic nervous system.

    Science.gov (United States)

    Kalra, Roma; Singh, Shashi P; Razani-Boroujerdi, Seddigheh; Langley, Raymond J; Blackwell, Walter B; Henderson, Rogene F; Sopori, Mohan L

    2002-10-15

    The nerve gas sarin is a potent cholinergic agent, and exposure to high doses may cause neurotoxicity and death. Subclinical exposures to sarin have been postulated to contribute to the Gulf War syndrome; however, the biological effects of subclinical exposure are largely unknown. In this communication, evidence shows that subclinical doses (0.2 and 0.4 mg/m(3)) of sarin administered by inhalation to F344 rats for 1 h/day for 5 or 10 days inhibited the anti-sheep red blood cell antibody-forming cell response of spleen cells without affecting the distribution of lymphocyte subpopulations in the spleen. Moreover, sarin suppressed T cell responses, including the concanavalin A (Con A) and the anti-alphabeta-T cell receptor (TCR) antibody-induced T cell proliferation and the rise in the intracellular calcium following TCR ligation. These concentrations of sarin altered regional but not total brain acetylcholinesterase activity. Interestingly, serum corticosterone levels of the sarin-treated animals were dramatically lower than the control animals, indicating that sarin-induced immunosuppression did not result from the activation of the hypothalamus-pituitary-adrenal (HPA) axis. Pretreatment of animals with the ganglionic blocker chlorisondamine abrogated the inhibitory effects of sarin on spleen cell proliferation in response to Con A and anti-TCR antibodies. These results suggest that the effects of sarin on T cell responsiveness are mediated via the autonomic nervous system and are independent of the HPA axis.

  2. Protective immunization with B16 melanoma induces antibody response and not cytotoxic T cell response

    International Nuclear Information System (INIS)

    Sarzotti, M.; Sriyuktasuth, P.; Klimpel, G.R.; Cerny, J.

    1986-01-01

    C57BL/6 mice immunized with three intraperitoneal injections of syngeneic, irradiated B16 melanoma cells, became resistant to B16 tumor challenge. Immunized mice had high levels of serum antibody against a membrane antigen of B16 cells. The B16 antigen recognized by the anti-B16 sera formed a major band of 90 KD in gel electrophoresis. The anti-B16 antibody was partially protective when mixed with B16 cells and injected into normal recipient mice. Surprisingly, B16 resistance mice were incapable of generating cytotoxic T cells (CTL) specific for the B16 tumor. Both spleen and lymph node cell populations from immunized mice did not generate B16-specific CTL. Allogeneic mice (DBA/2 or C3H) were also unable to generate B16-specific CTL: however, alloreactive CTL produced in these strains of mice by immunization with C57BL/6 lymphocytes, did kill B16 target cells. Interestingly, spleen cells from syngeneic mice immunized with B16 tumor produced 6-fold more interleukin-2 (IL-2) than normal spleen cells, in vitro. These data suggest that immunization with B16 tumor activates a helper subset of T cells (for antibody and IL-2 production) but not the effector CTL response

  3. MAVS Is Essential for Primary CD4+T Cell Immunity but Not for Recall T Cell Responses following an Attenuated West Nile Virus Infection.

    Science.gov (United States)

    Luo, Huanle; Winkelmann, Evandro; Xie, Guorui; Fang, Rong; Peng, Bi-Hung; Li, Li; Lazear, Helen M; Paessler, Slobodan; Diamond, Michael S; Gale, Michael; Barrett, Alan D; Wang, Tian

    2017-03-15

    The use of pathogen recognition receptor (PRR) agonists and the molecular mechanisms involved have been the major focus of research in individual vaccine development. West Nile virus (WNV) nonstructural (NS) 4B-P38G mutant has several features for an ideal vaccine candidate, including significantly reduced neuroinvasiveness, induction of strong adaptive immunity, and protection of mice from wild-type (WT) WNV infection. Here, we determined the role of mitochondrial antiviral signaling protein (MAVS), the adaptor protein for RIG-I-like receptor in regulating host immunity against the NS4B-P38G vaccine. We found that Mavs -/- mice were more susceptible to NS4B-P38G priming than WT mice. Mavs -/- mice had a transiently reduced production of antiviral cytokines and an impaired CD4 + T cell response in peripheral organs. However, antibody and CD8 + T cell responses were minimally affected. NS4B-P38G induced lower type I interferon (IFN), IFN-stimulating gene, and proinflammatory cytokine responses in Mavs -/- dendritic cells and subsequently compromised the antigen-presenting capacity for CD4 + T cells. Interestingly, Mavs -/- mice surviving NS4B-P38G priming were all protected from a lethal WT WNV challenge. NS4B-P38G-primed Mavs -/- mice exhibited equivalent levels of protective CD4 + T cell recall response, a modestly reduced WNV-specific IgM production, but more robust CD8 + T cell recall response. Taken together, our results suggest that MAVS is essential for boosting optimal primary CD4 + T cell responses upon NS4B-P38G vaccination and yet is dispensable for host protection and recall T cell responses during secondary WT WNV infection. IMPORTANCE The production of innate cytokines induced by the recognition of pathogen recognition receptors (PRRs) via their cognate ligands are critical for enhancing antigen-presenting cell functions and influencing T cell responses during microbial infection. The use of PRR agonists and the underlying molecular mechanisms have

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

    Directory of Open Access Journals (Sweden)

    Sarah Hutchinson

    2011-02-01

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

  5. Actin-dependent activation of serum response factor in T cells by the viral oncoprotein tip

    Directory of Open Access Journals (Sweden)

    Katsch Kristin

    2012-03-01

    Full Text Available Abstract Serum response factor (SRF acts as a multifunctional transcription factor regulated by mutually exclusive interactions with ternary complex factors (TCFs or myocardin-related transcription factors (MRTFs. Binding of Rho- and actin-regulated MRTF:SRF complexes to target gene promoters requires an SRF-binding site only, whereas MAPK-regulated TCF:SRF complexes in addition rely on flanking sequences present in the serum response element (SRE. Here, we report on the activation of an SRE luciferase reporter by Tip, the viral oncoprotein essentially contributing to human T-cell transformation by Herpesvirus saimiri. SRE activation in Tip-expressing Jurkat T cells could not be attributed to triggering of the MAPK pathway. Therefore, we further analyzed the contribution of MRTF complexes. Indeed, Tip also activated a reporter construct responsive to MRTF:SRF. Activation of this reporter was abrogated by overexpression of a dominant negative mutant of the MRTF-family member MAL. Moreover, enrichment of monomeric actin suppressed the Tip-induced reporter activity. Further upstream, the Rho-family GTPase Rac, was found to be required for MRTF:SRF reporter activation by Tip. Initiation of this pathway was strictly dependent on Tip's ability to interact with Lck and on the activity of this Src-family kinase. Independent of Tip, T-cell stimulation orchestrates Src-family kinase, MAPK and actin pathways to induce SRF. These findings establish actin-regulated transcription in human T cells and suggest its role in viral oncogenesis.

  6. Increased sequence diversity coverage improves detection of HIV-Specific T cell responses

    DEFF Research Database (Denmark)

    Frahm, N.; Kaufmann, D.E.; Yusim, K.

    2007-01-01

    assay, these "toggled" peptides detected HIV-specific CD4(+) and CD8(+) T cell responses of significantly higher breadth and magnitude than matched consensus peptides. The observed increases were explained by a closer match of the toggled peptides to the autologous viral sequence. Toggled peptides......The accurate identification of HIV-specific T cell responses is important for determining the relationship between immune response, viral control, and disease progression. HIV-specific immune responses are usually measured using peptide sets based on consensus sequences, which frequently miss...... responses to regions where test set and infecting virus differ. In this study, we report the design of a peptide test set with significantly increased coverage of HIV sequence diversity by including alternative amino acids at variable positions during the peptide synthesis step. In an IFN-gamma ELISpot...

  7. Synthetic peptides containing B- and T-cell epitope of dengue virus-2 E domain III provoked B- and T-cell responses.

    Science.gov (United States)

    Li, Shanfeng; Peng, Liang; Zhao, Wei; Zhong, Hua; Zhang, Fuchun; Yan, Ziqiang; Cao, Hong

    2011-05-09

    Our previous work applied a combination of bioinformatics approaches and in vitro assays to identify the dengue-2 virus (DENV-2)-specific B- and T-cell epitopes. In this report, we first evaluated the antigenicity of both B- and T-cell epitopes reacting with different sera against DENV-2 by ELISA as well as the ability of T-cell epitope to activate CD4(+) T-cell producing IFN-γ using ELISPOT, which showed a specific reactivity between either B- or T-cell epitope and DENV-2 antisera, and a significant increase of IFN-γ producing cells in DENV-2 infected mice. Then, a multi-epitope peptide containing the above B-, T-cell epitopes of envelope domain III (EDIII) of DENV-2 and pan-DR epitope (PADRE) was bioinformatically designed and synthesized. The verification of its immunogenicity and protective effect was performed in in vitro and in vivo experiments. The results showed that a high level of antibody in mice elicited by the multi-epitope peptide was detected by ELISA and the anti-peptide sera binding to the vero cells infected with DEN-2 was observed with immunofluorescence test. More importantly, the peptide could induce lymphoproliferation in vitro and a predominant Th1 type of immune response was examined by flow cytometry. We also found that the virus replication in the mice vaccinated with the multi-epitope peptide was obviously less than that of the control groups. These results may provide some important information for the development of dengue vaccine. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Increase in IFNγ(-IL-2(+ cells in recent human CD4 T cell responses to 2009 pandemic H1N1 influenza.

    Directory of Open Access Journals (Sweden)

    Jason M Weaver

    Full Text Available Human CD4 T cell recall responses to influenza virus are strongly biased towards Type 1 cytokines, producing IFNγ, IL-2 and TNFα. We have now examined the effector phenotypes of CD4 T cells in more detail, particularly focusing on differences between recent versus long-term, multiply-boosted responses. Peptides spanning the proteome of temporally distinct influenza viruses were distributed into pools enriched for cross-reactivity to different influenza strains, and used to stimulate antigen-specific CD4 T cells representing recent or long-term memory. In the general population, peptides unique to the long-circulating influenza A/New Caledonia/20/99 (H1N1 induced Th1-like responses biased toward the expression of IFNγ(+TNFα(+ CD4 T cells. In contrast, peptide pools enriched for non-cross-reactive peptides of the pandemic influenza A/California/04/09 (H1N1 induced more IFNγ(-IL-2(+TNFα(+ T cells, similar to the IFNγ(-IL-2(+ non-polarized, primed precursor T cells (Thpp that are a predominant response to protein vaccination. These results were confirmed in a second study that compared samples taken before the 2009 pandemic to samples taken one month after PCR-confirmed A/California/04/09 infection. There were striking increases in influenza-specific TNFα(+, IFNγ(+, and IL-2(+ cells in the post-infection samples. Importantly, peptides enriched for non-cross-reactive A/California/04/09 specificities induced a higher proportion of Thpp-like IFNγ(-IL-2(+TNFα(+ CD4 T cells than peptide pools cross-reactive with previous influenza strains, which induced more Th1 (IFNγ(+TNFα(+ responses. These IFNγ(-IL-2(+TNFα(+ CD4 T cells may be an important target population for vaccination regimens, as these cells are induced upon infection, may have high proliferative potential, and may play a role in providing future effector cells during subsequent infections.

  9. Only a subset of phosphoantigen-responsive gamma9delta2 T cells mediate protective tuberculosis immunity.

    Science.gov (United States)

    Spencer, Charles T; Abate, Getahun; Blazevic, Azra; Hoft, Daniel F

    2008-10-01

    Mycobacterium tuberculosis and Mycobacterium bovis bacillus Calmette-Guérin (BCG) induce potent expansions of human memory Vgamma(9)(+)Vdelta(2)(+) T cells capable of IFN-gamma production, cytolytic activity, and mycobacterial growth inhibition. Certain phosphoantigens expressed by mycobacteria can stimulate gamma(9)delta(2) T cell expansions, suggesting that purified or synthetic forms of these phosphoantigens may be useful alone or as components of new vaccines or immunotherapeutics. However, we show that while mycobacteria-activated gamma(9)delta(2) T cells potently inhibit intracellular mycobacterial growth, phosphoantigen-activated gamma(9)delta(2) T cells fail to inhibit mycobacteria, although both develop similar effector cytokine and cytolytic functional capacities. gamma(9)delta(2) T cells receiving TLR-mediated costimulation during phosphoantigen activation also failed to inhibit mycobacterial growth. We hypothesized that mycobacteria express Ags, other than the previously identified phosphoantigens, that induce protective subsets of gamma(9)delta(2) T cells. Testing this hypothesis, we compared the TCR sequence diversity of gamma(9)delta(2) T cells expanded with BCG-infected vs phosphoantigen-treated dendritic cells. BCG-stimulated gamma(9)delta(2) T cells displayed a more restricted TCR diversity than phosphoantigen-activated gamma(9)delta(2) T cells. In addition, only a subset of phosphoantigen-activated gamma(9)delta(2) T cells functionally responded to mycobacteria-infected dendritic cells. Furthermore, differential inhibitory functions of BCG- and phosphoantigen-activated gamma(9)delta(2) T cells were confirmed at the clonal level and were not due to differences in TCR avidity. Our results demonstrate that BCG infection can activate and expand protective subsets of phosphoantigen-responsive gamma(9)delta(2) T cells, and provide the first indication that gamma(9)delta(2) T cells can develop pathogen specificity similar to alphabeta T cells. Specific

  10. Antigen-Specific B Cells Reactivate an Effective Cytotoxic T Cell Response against Phagocytosed Salmonella through Cross-Presentation

    NARCIS (Netherlands)

    de Wit, Jelle; Souwer, Yuri; Jorritsma, Tineke; Klaasse Bos, Hanny; ten Brinke, Anja; Neefjes, Jacques; van Ham, S. Marieke

    2010-01-01

    Background: The eradication of facultative intracellular bacterial pathogens, like Salmonella typhi, requires the concerted action of both the humoral immune response and the cytotoxic CD8(+) T cell response. Dendritic cells (DCs) are considered to orchestrate the cytotoxic CD8(+) T cell response

  11. Elevated and cross‐responsive CD1a‐reactive T cells in bee and wasp venom allergic individuals

    Science.gov (United States)

    Subramaniam, Sumithra; Aslam, Aamir; Misbah, Siraj A.; Salio, Mariolina; Cerundolo, Vincenzo; Moody, D Branch

    2015-01-01

    The role of CD1a‐reactive T cells in human allergic disease is unknown. We have previously shown that circulating CD1a‐reactive T cells recognize neolipid antigens generated by bee and wasp venom phospholipase, and here tested the hypothesis that venom‐responsive CD1a‐reactive T cells associate with venom allergy. Circulating T cells from bee and wasp venom allergic individuals, before and during immunotherapy, were exposed to CD1a‐transfected K562 cells in the presence of wasp or bee venom. T‐cell response was evaluated based on IFNγ, GM‐CSF, and IL‐13 cytokine production. Venom allergic individuals showed significantly higher frequencies of IFN‐γ, GM‐CSF, and IL‐13 producing CD1a‐reactive T cells responsive to venom and venom‐derived phospholipase than healthy individuals. Venom‐responsive CD1a‐reactive T cells were cross‐responsive between wasp and bee suggesting shared pathways of allergenicity. Frequencies of CD1a‐reactive T cells were initially induced during subcutaneous immunotherapy, peaking by weeks 5, but then reduced despite escalation of antigen dose. Our current understanding of venom allergy and immunotherapy is largely based on peptide and protein‐specific T cell and antibody responses. Here, we show that lipid antigens and CD1a‐reactive T cells associate with the allergic response. These data have implications for mechanisms of allergy and approaches to immunotherapy. PMID:26518614

  12. Enhancement of T-cell-mediated antitumor response: angiostatic adjuvant to immunotherapy against cancer.

    Science.gov (United States)

    Dings, Ruud P M; Vang, Kieng B; Castermans, Karolien; Popescu, Flavia; Zhang, Yan; Oude Egbrink, Mirjam G A; Mescher, Matthew F; Farrar, Michael A; Griffioen, Arjan W; Mayo, Kevin H

    2011-05-15

    Tumor-released proangiogenic factors suppress endothelial adhesion molecule (EAM) expression and prevent leukocyte extravasation into the tumor. This is one reason why immunotherapy has met with limited success in the clinic. We hypothesized that overcoming EAM suppression with angiogenesis inhibitors would increase leukocyte extravasation and subsequently enhance the effectiveness of cellular immunotherapy. Intravital microscopy, multiple color flow cytometry, immunohistochemistry, and various tumor mouse (normal and T-cell deficient) models were used to investigate the temporal dynamics of cellular and molecular events that occur in the tumor microenvironment during tumor progression and angiostatic intervention. We report that while EAM levels and T-cell infiltration are highly attenuated early on in tumor growth, angiostatic therapy modulates these effects. In tumor models with normal and T-cell-deficient mice, we show the active involvement of the adaptive immune system in cancer and differentiate antiangiogenic effects from antiangiogenic mediated enhancement of immunoextravasation. Our results indicate that a compromised immune response in tumors can be obviated by the use of antiangiogenic agents. Finally, with adoptive transfer studies in mice, we show that a phased combination of angiostatic therapy and T-cell transfer significantly (P response within the tumor microenvironment, in particular as a consequence of the temporal dynamics of EAM levels. Moreover, our results suggest that adjuvant therapy with angiogenesis inhibitors holds promise for cellular immunotherapy in the clinic. ©2011 AACR.

  13. The Fas-Associated Death Domain Protein (FADD) is Required in Apoptosis and TLR-induced Proliferative Responses in B Cells1

    Science.gov (United States)

    Imtiyaz, Hongxia Z.; Rosenberg, Stephen; Zhang, Yuhang; Rahman, Ziaur S. M.; Hou, Ying-Ju; Manser, Tim L.; Zhang, Jianke

    2011-01-01

    The Fas-associated death domain protein FADD/Mort1 is a signaling adaptor protein which mediates the activation of caspase 8 during death receptor-induced apoptosis. Disruption of FADD in germ cells results in death receptor-independent embryonic lethality in mice. Previous studies indicated that in addition to its function in apoptosis, FADD is also required in peripheral T cell homeostasis and TCR-induced proliferative responses. In this report, we generated B cell-specific FADD-deficient mice and showed that deletion of FADD at the pro-B cell stage had minor effects on B cell development in the bone marrow, and resulted in increased splenic and lymph node B cell numbers and decreased peritoneal B1 cell numbers. As in T cells, a FADD deficiency inhibited Fas-induced apoptosis in B cells. However, B cell proliferative responses induced by stimulation of the BCR and CD40 using anti-IgM or anti-CD40 antibodies were unaffected by the absence of FADD. Further analyses revealed that FADD-deficient B cells were defective in proliferative responses induced by treatments with dsRNA and LPS which stimulate TLR3 and TLR4 respectively. Therefore, in addition to its apoptotic function, FADD also plays a role in TLR3- and TLR4-induced proliferative responses in B cells. PMID:16709845

  14. Survivin-specific T-cell reactivity correlates with tumor response and patient survival

    DEFF Research Database (Denmark)

    Becker, Jürgen C; Andersen, Mads H; Hofmeister-Müller, Valeska

    2012-01-01

    Therapeutic vaccination directed to induce an anti-tumoral T-cell response is a field of extensive investigation in the treatment of melanoma. However, many vaccination trials in melanoma failed to demonstrate a correlation between the vaccine-specific immune response and therapy outcome. This has...... been mainly attributed to immune escape by antigen loss, rendering us in the need of new vaccination targets....

  15. Functional signatures of human CD4 and CD8 T cell responses to Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Teresa ePrezzemolo

    2014-04-01

    Full Text Available With 1.4 million deaths and 8.7 million new cases in 2011, tuberculosis (TB remains a global health care problem and together with HIV and Malaria represents the one of the three infectious diseases world-wild. Control of the global TB epidemic has been impaired by the lack of an effective vaccine, by the emergence of drug-resistant forms of Mycobacterium tuberculosis (Mtb and by the lack of sensitive and rapid diagnostics. It is estimated, by epidemiological reports, that one third of the world’s population is latently infected with Mtb, but the majority of infected individuals develops long-lived protective immunity, which controls and contains Mtb in a T cell-dependent manner. Development of TB disease results from interactions among the environment, the host, and the pathogen, and known risk factors include HIV coinfection, immunodeficiency, diabetes mellitus, overcrowding, malnutrition, and general poverty; therefore an effective T cell response determines whether the infection resolves or develops into clinically evident disease. Consequently, there is great interest in determining which T cells subsets mediate anti-mycobacterial immunity, delineating their effector functions. On the other hand, many aspects remain unsolved in understanding why some individuals are protected from Mtb infection while others go on to develop disease.Several studies have demonstrated that CD4+ T cells are involved in protection against Mtb, as supported by the evidence that CD4+ T cell depletion is responsible for Mtb reactivation in HIV-infected individuals. There are many subsets of CD4+ T cells, such as T-helper 1 (Th1, Th2, Th17, and regulatory T cells (Tregs, and all these subsets cooperate or interfere with each other to control infection; the dominant subset may differ between active and latent Mtb infection cases. Mtb-specific CD4+ Th1 cell response is considered to have a protective role for the ability to produce cytokines such as IFN- or TNF

  16. The CD3-zeta chimeric antigen receptor overcomes TCR Hypo-responsiveness of human terminal late-stage T cells.

    Directory of Open Access Journals (Sweden)

    Gunter Rappl

    Full Text Available Adoptive therapy of malignant diseases with tumor-specific cytotoxic T cells showed remarkable efficacy in recent trials. Repetitive T cell receptor (TCR engagement of target antigen, however, inevitably ends up in hypo-responsive cells with terminally differentiated KLRG-1(+ CD57(+ CD7(- phenotype limiting their therapeutic efficacy. We here revealed that hypo-responsiveness of CMV-specific late-stage CD8(+ T cells is due to reduced TCR synapse formation compared to younger cells. Membrane anchoring of TCR components contributes to T cell hypo-responsiveness since dislocation of galectin-3 from the synapse by swainsonine restored both TCR synapse formation and T cell response. Transgenic expression of a CD3-zeta signaling chimeric antigen receptor (CAR recovered hypo-responsive T cells to full effector functions indicating that the defect is restricted to TCR membrane components while synapse formation of the transgenic CAR was not blocked. CAR engineered late-stage T cells released cytokines and mediated redirected cytotoxicity as efficiently as younger effector T cells. Our data provide a rationale for TCR independent, CAR mediated activation in the adoptive cell therapy to avoid hypo-responsiveness of late-stage T cells upon repetitive antigen encounter.

  17. Interferon-beta induces distinct gene expression response patterns in human monocytes versus T cells.

    Directory of Open Access Journals (Sweden)

    Noa Henig

    Full Text Available BACKGROUND: Monocytes, which are key players in innate immunity, are outnumbered by neutrophils and lymphocytes among peripheral white blood cells. The cytokine interferon-β (IFN-β is widely used as an immunomodulatory drug for multiple sclerosis and its functional pathways in peripheral blood mononuclear cells (PBMCs have been previously described. The aim of the present study was to identify novel, cell-specific IFN-β functions and pathways in tumor necrosis factor (TNF-α-activated monocytes that may have been missed in studies using PBMCs. METHODOLOGY/PRINCIPAL FINDINGS: Whole genome gene expression profiles of human monocytes and T cells were compared following in vitro priming to TNF-α and overnight exposure to IFN-β. Statistical analyses of the gene expression data revealed a cell-type-specific change of 699 transcripts, 667 monocyte-specific transcripts, 21 T cell-specific transcripts and 11 transcripts with either a difference in the response direction or a difference in the magnitude of response. RT-PCR revealed a set of differentially expressed genes (DEGs, exhibiting responses to IFN-β that are modulated by TNF-α in monocytes, such as RIPK2 and CD83, but not in T cells or PBMCs. Known IFN-β promoter response elements, such as ISRE, were enriched in T cell DEGs but not in monocyte DEGs. The overall directionality of the gene expression regulation by IFN-β was different in T cells and monocytes, with up-regulation more prevalent in T cells, and a similar extent of up and down-regulation recorded in monocytes. CONCLUSIONS: By focusing on the response of distinct cell types and by evaluating the combined effects of two cytokines with pro and anti-inflammatory activities, we were able to present two new findings First, new IFN-β response pathways and genes, some of which were monocytes specific; second, a cell-specific modulation of the IFN-β response transcriptome by TNF-α.

  18. Fragmentation of SIV-gag vaccine induces broader T cell responses.

    Directory of Open Access Journals (Sweden)

    Adel Benlahrech

    Full Text Available High mutation rates of human immunodeficiency virus (HIV allows escape from T cell recognition preventing development of effective T cell vaccines. Vaccines that induce diverse T cell immune responses would help overcome this problem. Using SIV gag as a model vaccine, we investigated two approaches to increase the breadth of the CD8 T cell response. Namely, fusion of vaccine genes to ubiquitin to target the proteasome and increase levels of MHC class I peptide complexes and gene fragmentation to overcome competition between epitopes for presentation and recognition.three vaccines were compared: full-length unmodified SIV-mac239 gag, full-length gag fused at the N-terminus to ubiquitin and 7 gag fragments of equal size spanning the whole of gag with ubiquitin-fused to the N-terminus of each fragment. Genes were cloned into a replication defective adenovirus vector and immunogenicity assessed in an in vitro human priming system. The breadth of the CD8 T cell response, defined by the number of distinct epitopes, was assessed by IFN-γ-ELISPOT and memory phenotype and cytokine production evaluated by flow cytometry. We observed an increase of two- to six-fold in the number of epitopes recognised in the ubiquitin-fused fragments compared to the ubiquitin-fused full-length gag. In contrast, although proteasomal targeting was achieved, there was a marked reduction in the number of epitopes recognised in the ubiquitin-fused full-length gag compared to the full-length unmodified gene, but there were no differences in the number of epitope responses induced by non-ubiquitinated full-length gag and the ubiquitin-fused mini genes. Fragmentation and ubiquitination did not affect T cell memory differentiation and polyfunctionality, though most responses were directed against the Ad5 vector.Fragmentation but not fusion with ubiquitin increases the breadth of the CD8 T vaccine response against SIV-mac239 gag. Thus gene fragmentation of HIV vaccines may maximise

  19. CD27 instructs CD4+ T cells to provide help for the memory CD8+ T cell response after protein immunization

    NARCIS (Netherlands)

    Xiao, Yanling; Peperzak, Victor; Keller, Anna M.; Borst, Jannie

    2008-01-01

    For optimal quality, memory CD8(+) T cells require CD4(+) T cell help. We have examined whether CD4(+) T cells require CD27 to deliver this help, in a model of intranasal OVA protein immunization. CD27 deficiency reduced the capacity of CD4(+) T cells to support Ag-specific CD8(+) T cell

  20. Kinetics of T cell-activation molecules in response to Mycobacterium tuberculosis antigens

    Directory of Open Access Journals (Sweden)

    Antas Paulo RZ

    2002-01-01

    Full Text Available The phenotypic features acquired subsequent to antigen-specific stimulation in vitro were evaluated by means of the kinetic expressions of CD69 and CD25 activation molecules on T lymphocytes and assayed by flow cytometry in response to PPD, Ag85B, and ferritin in PPD-positive healthy control individuals. In response to PHA, CD69 staining on both CD4+ and CD8+ T cells became initially marked after 4 h, peaked at 24 h, and quickly decreased after 120 h. For CD25, a latter expression was detected around 8 h, having increased after 96 h. As expected, the response rate to the mycobacterial antigens was much lower than that to the mitogen. Positive staining was high after 96 h for CD25 and after 24 h for CD69. CD69 expression was significantly enhanced (p < 0.05 on CD8+ as compared to CD4+ T cells. High levels were also found between 96-120 h. Regarding Ag85B, CD25+ cells were mostly CD4+ instead of CD8+ T cells. Moreover, in response to ferritin, a lower CD25 expression was noted. The present data will allow further characterization of the immune response to new mycobacterial-specific antigens and their evaluation for possible inclusion in developing new diagnostic techniques for tuberculosis as well in a new vaccine to prevent the disease.

  1. Sustained Specific and Cross-Reactive T Cell Responses to Zika and Dengue Virus NS3 in West Africa.

    Science.gov (United States)

    Herrera, Bobby Brooke; Tsai, Wen-Yang; Chang, Charlotte A; Hamel, Donald J; Wang, Wei-Kung; Lu, Yichen; Mboup, Souleymane; Kanki, Phyllis J

    2018-04-01

    Recent studies on the role of T cells in Zika virus (ZIKV) infection have shown that T cell responses to Asian ZIKV infection are important for protection, and that previous dengue virus (DENV) exposure amplifies the protective T cell response to Asian ZIKV. Human T cell responses to African ZIKV infection, however, remain unexplored. Here, we utilized the modified anthrax toxin delivery system to develop a flavivirus enzyme-linked immunosorbent spot (ELISPOT) assay. Using human ZIKV and DENV samples from Senegal, West Africa, our results demonstrate specific and cross-reactive T cell responses to nonstructural protein 3 (NS3). Specifically, we found that T cell responses to NS3 protease are ZIKV and DENV specific, but responses to NS3 helicase are cross-reactive. Sequential sample analyses revealed immune responses sustained many years after infection. These results have important implications for African ZIKV/DENV vaccine development, as well as for potential flavivirus diagnostics based on T cell responses. IMPORTANCE The recent Zika virus (ZIKV) epidemic in Latin America and the associated congenital microcephaly and Guillain-Barré syndrome have raised questions as to why we have not recognized these distinct clinical diseases in Africa. The human immunologic response to ZIKV and related flaviviruses in Africa represents a research gap that may shed light on the mechanisms contributing to protection. The goal of our study was to develop an inexpensive assay to detect and characterize the T cell response to African ZIKV and DENV. Our data show long-term specific and cross-reactive human immune responses against African ZIKV and DENV, suggesting the usefulness of a diagnostic based on the T cell response. Additionally, we show that prior flavivirus exposure influences the magnitude of the T cell response. The identification of immune responses to African ZIKV and DENV is of relevance to vaccine development. Copyright © 2018 American Society for Microbiology.

  2. Next-generation detection of antigen-responsive T cells using DNA barcode-labeled peptidemajor histocompatibility complex I multimers

    DEFF Research Database (Denmark)

    Bentzen, Amalie Kai; Marquard, Andrea Marion; Lyngaa, Rikke Birgitte

    2016-01-01

    diversity of T cell recognition in humans. Consequently it has been impossible to comprehensively analyze T cell responsiveness in cancer, infectious and autoimmune diseases. We present and validate a novel technology that enables parallel detection of numerous different peptide-MHC responsive T cells...... in asingle sample using >1000 different peptide-MHC multimers labeled with individual DNA barcodes. After isolation of MHC multimer binding T cells their recognition are revealed by amplification and sequencing of the MHC multimer-associated DNA barcodes. The relative frequency of the sequenced DNA barcodes...... originating from a given peptide-MHC motif relates to the size of the antigenresponsive T cell population. We have demonstrated the use of large panels of >1000 DNA barcoded MHC multimers for detection of rare T cell populations of virus and cancer-restricted origin in various tissues and compared...

  3. Modeling T cell antigen discrimination based on feedback control of digital ERK responses.

    Directory of Open Access Journals (Sweden)

    2005-11-01

    Full Text Available T-lymphocyte activation displays a remarkable combination of speed, sensitivity, and discrimination in response to peptide-major histocompatibility complex (pMHC ligand engagement of clonally distributed antigen receptors (T cell receptors or TCRs. Even a few foreign pMHCs on the surface of an antigen-presenting cell trigger effective signaling within seconds, whereas 1 x 10(5-1 x 10(6 self-pMHC ligands that may differ from the foreign stimulus by only a single amino acid fail to elicit this response. No existing model accounts for this nearly absolute distinction between closely related TCR ligands while also preserving the other canonical features of T-cell responses. Here we document the unexpected highly amplified and digital nature of extracellular signal-regulated kinase (ERK activation in T cells. Based on this observation and evidence that competing positive- and negative-feedback loops contribute to TCR ligand discrimination, we constructed a new mathematical model of proximal TCR-dependent signaling. The model made clear that competition between a digital positive feedback based on ERK activity and an analog negative feedback involving SH2 domain-containing tyrosine phosphatase (SHP-1 was critical for defining a sharp ligand-discrimination threshold while preserving a rapid and sensitive response. Several nontrivial predictions of this model, including the notion that this threshold is highly sensitive to small changes in SHP-1 expression levels during cellular differentiation, were confirmed by experiment. These results combining computation and experiment reveal that ligand discrimination by T cells is controlled by the dynamics of competing feedback loops that regulate a high-gain digital amplifier, which is itself modulated during differentiation by alterations in the intracellular concentrations of key enzymes. The organization of the signaling network that we model here may be a prototypic solution to the problem of achieving

  4. Alterations in regulatory T cells induced by specific oligosaccharides improve vaccine responsiveness in mice.

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    Marcel A Schijf

    Full Text Available Prophylactic vaccinations are generally performed to protect naïve individuals with or without suppressed immune responsiveness. In a mouse model for Influenza vaccinations the specific alterations of CD4(+CD25(+Foxp3(+ regulatory T-cells (Tregs in the immune modulation induced by orally supplied oligosaccharides containing scGOS/lcFOS/pAOS was assessed. This dietary intervention increased vaccine specific DTH responses. In addition, a significant increased percentage of T-bet(+ (Th1 activated CD69(+CD4(+ T cells (p<0.001 and reduced percentage of Gata-3(+ (Th2 activated CD69(+CD4(+T cells (p<0.001 was detected in the mesenteric lymph nodes (MLN of mice receiving scGOS/lcFOS/pAOS compared to control mice. Although no difference in the number or percentage of Tregs (CD4(+Foxp3(+ could be determined after scGOS/lcFOS/pAOS intervention, the percentage of CXCR3 (+ /T-bet(+ (Th1-Tregs was significantly reduced (p<0.05 in mice receiving scGOS/lcFOS/pAOS as compared to mice receiving placebo diets. Moreover, although no absolute difference in suppressive capacity could be detected, an alteration in cytokine profile suggests a regulatory T cell shift towards a reducing Th1 suppression profile, supporting an improved vaccination response.These data are indicative for improved vaccine responsiveness due to reduced Th1 suppressive capacity in the Treg population of mice fed the oligosaccharide specific diet, showing compartmentalization within the Treg population. The modulation of Tregs to control immune responses provides an additional arm of intervention using alternative strategies possibly leading to the development of improved vaccines.

  5. Bifidobacterium breve attenuates murine dextran sodium sulfate-induced colitis and increases regulatory T cell responses.

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    Bin Zheng

    Full Text Available While some probiotics have shown beneficial effects on preventing or treating colitis development, others have shown no effects. In this study, we have assessed the immunomodulating effects of two probiotic strains, Lactobacillus rhamnosus (L. rhamnosus and Bifidobacterium breve (B. breve on T cell polarization in vitro, using human peripheral blood mononuclear cells (PBMC, and in vivo, using murine dextran sodium sulfate (DSS colitis model. With respect to the latter, the mRNA expression of T cell subset-associated transcription factors and cytokines in the colon was measured and the T helper type (Th 17 and regulatory T cell (Treg subsets were determined in the Peyer's patches. Both L. rhamnosus and B. breve incubations in vitro reduced Th17 and increased Th2 cell subsets in human PBMCs. In addition, B. breve incubation was also able to reduce Th1 and increase Treg cell subsets in contrast to L. rhamnosus. In vivo intervention with B. breve, but not L. rhamnosus, significantly attenuated the severity of DSS-induced colitis. In DSS-treated C57BL/6 mice, intervention with B. breve increased the expression of mRNA encoding for Th2- and Treg-associated cytokines in the distal colon. In addition, intervention with B. breve led to increases of Treg and decreases of Th17 cell subsets in Peyer's patches of DSS-treated mice. B. breve modulates T cell polarization towards Th2 and Treg cell-associated responses in vitro and in vivo. In vivo B. breve intervention ameliorates DSS-induced colitis symptoms and this protective effect may mediated by its effects on the T-cell composition.

  6. Regulation of Gag- and Env-Specific CD8+ T Cell Responses in ART-Naïve HIV-Infected Patients: Potential Implications for Individualized Immunotherapy.

    Science.gov (United States)

    Prebensen, Christian; Lind, Andreas; Dyrhol-Riise, Anne-Ma; Kvale, Dag

    2016-01-01

    Strategies to develop a functional cure for HIV infection will likely require boosting of effector T cell responses to eliminate reactivated, latently infected cells. We have recently explored an assay for assessing antigen-specific regulation of T cell proliferation, which was related to clinical progression in untreated patients and to vaccine efficacy in two trials of therapeutic Gag-based vaccines. We here expand the same assay to further investigate regulation mediated by various inhibitory pathways. Peripheral blood mononuclear cells from 26 asymptomatic HIV-infected, antiretroviral therapy-naïve patients were stimulated with Gag and Env overlapping peptide panels for 5 days. Monoclonal antibodies (mAbs) blocking inhibitory mediators interleukin (IL) 10, transforming growth factor (TGF) β, programmed death ligand (PD-L) 1 and herpes virus entry mediator (HVEM) were added to parallel cultures. Functional T cell regulation (FTR) was defined as the difference in proliferation between stimulated cultures with and without blocking mAbs. FTR was detected in 54% of patients. Blockade of IL-10/PD-L1 and IL10/TGF-β detected all cases with Gag- and Env-associated FTR, respectively. In accordance with previous findings, isolated Env FTR was associated with higher plasma HIV RNA and lower CD4 counts, while patients with both Gag and Env FTR also had higher Gag- and Env-specific proliferative CD8+ T cell responses. There was no association between FTR and frequencies of activated regulatory T cells. In conclusion, we observed substantial heterogeneity in FTR between patients, inhibitory pathways and HIV antigens. FTR may help to individualize immunomodulation and warrants further assessment in clinical immunotherapy trials.

  7. GM-CSF increases the ability of cultured macrophages to support autologous CD4+ T-cell proliferation in response to Dermatophagoides pteronyssinus and PPD antigen.

    Science.gov (United States)

    Caulfield, J J; Hawrylowicz, C M; Kemeny, D M; Lee, T H

    1997-01-01

    Previous studies have demonstrated an infiltration of monocytes and increased levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the asthmatic lung. To study the possible effects of this cytokine upon the differentiation and function of these newly recruited monocytes, we have developed a model in which monocytes isolated from human peripheral blood were differentiated into macrophages in serum in the presence or absence of GM-CSF. After 7 days, the macrophages increased in size and granularity, had increased phagocytic activity, and expressed various adhesion molecules, CD14 and major histocompatibility complex (MHC) class II. The effects of GM-CSF on antigen presentation by cultured macrophages on the antigen-specific proliferative response of CD4+ T cells to Dermatophagoides pteronyssinus or purified protein derivative of tuberculin and the mitogen phytohaemagglutinin was determined. CD4+ T-cell proliferation was reduced when either antigen was presented by macrophages cultured in serum alone, compared with the values obtained with freshly isolated monocytes. However, CD4+ cell proliferation was comparable to that observed with monocytes when antigen was presented by macrophages which had been pre-cultured with 50 U/ml GM-CSF. CD4+ T-cell proliferation to phytohaemagglutinin was similar when all three populations were used as accessory cells. High numbers of macrophages partially suppressed CD4+ T-cell proliferation in response to antigen presented by monocytes, but there was no significant difference between macrophages cultured in the presence or absence of GM-CSF. This data suggests that GM-CSF directs monocyte differentiation into macrophages with an antigen-presenting, rather than a suppressive, phenotype. Elevated levels of GM-CSF in the asthmatic lung may therefore maintain recently recruited monocytes in an inflammatory and T-cell activating state. Images Figure 2 Figure 3 PMID:9370934

  8. Phenotypic and functional characterization of human memory T cell responses to Burkholderia pseudomallei.

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    Patcharaporn Tippayawat

    Full Text Available Infection with the Gram-negative bacterium Burkholderia pseudomallei is an important cause of community-acquired lethal sepsis in endemic regions in southeast Asia and northern Australia and is increasingly reported in other tropical areas. In animal models, production of interferon-gamma (IFN-gamma is critical for resistance, but in humans the characteristics of IFN-gamma production and the bacterial antigens that are recognized by the cell-mediated immune response have not been defined.Peripheral blood from 133 healthy individuals who lived in the endemic area and had no history of melioidosis, 60 patients who had recovered from melioidosis, and 31 other patient control subjects were stimulated by whole bacteria or purified bacterial proteins in vitro, and IFN-gamma responses were analyzed by ELISPOT and flow cytometry.B. pseudomallei was a potent activator of human peripheral blood NK cells for innate production of IFN-gamma. In addition, healthy individuals with serological evidence of exposure to B. pseudomallei and patients recovered from active melioidosis developed CD4(+ (and CD8(+ T cells that recognized whole bacteria and purified proteins LolC, OppA, and PotF, members of the B. pseudomallei ABC transporter family. This response was primarily mediated by terminally differentiated T cells of the effector-memory (T(EMRA phenotype and correlated with the titer of anti-B. pseudomallei antibodies in the serum.Individuals living in a melioidosis-endemic region show clear evidence of T cell priming for the ability to make IFN-gamma that correlates with their serological status. The ability to detect T cell responses to defined B. pseudomallei proteins in large numbers of individuals now provides the opportunity to screen candidate antigens for inclusion in protein or polysaccharide-conjugate subunit vaccines against this important but neglected disease.

  9. Regulatory T Cells and Pro-inflammatory Responses Predominate in Children with Tuberculosis

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    Elizabeth Whittaker

    2017-04-01

    Full Text Available BackgroundFollowing infection with Mycobacterium tuberculosis (M.tb, children are more susceptible to develop disease particularly extrapulmonary disease than adults. The exact mechanisms required for containment of M.tb are not known, but would be important to identify correlates of protection.ObjectiveTo comprehensively analyze key immune responses to mycobacteria between HIV-negative children with extrapulmonary TB (EPTB compared to children with pulmonary TB (PTB or healthy controls.MethodsWhole blood was stimulated in vitro with mycobacteria for 24 h or 6 days to induce effector and memory responses. CD4, CD8, γδ, regulatory T cells, and their related cytokines were measured. Samples of children with tuberculosis (TB disease were analyzed both at time of diagnosis and at the end of TB treatment to determine if any differences were due to TB disease or an underlying host phenotype.ResultsSeventy-six children with TB disease (48 with PTB and 28 with EPTB and 83 healthy controls were recruited to the study. The frequency of CD4+CD25+CD39+FOXP3+ regulatory T cells and secreted IL10 were significantly higher in children with TB compared to healthy controls. IFNγ-, IL17-, and IL22-producing γδ T cells, IL22-producing CD4+ T cells and secreted pro-inflammatory cytokines (IFNγ, IL1β, and TNFα were significantly lower in children with TB disease compared to healthy controls. IFNγ-producing CD4+ T cells and Ki67+-proliferating CD4+ T cells, however, were present in equal numbers in both groups. Following treatment, these immune parameters recovered to “healthy” levels or greater in children with PTB, but not those with extrapulmonary TB.ConclusionIn children with TB disease, a predominantly immune regulatory state is present. These immune findings do not distinguish between children with PTB and EPTB at the time of diagnosis. Following treatment, these inflammatory responses recover in PTB, suggesting that the effect is disease

  10. Rotavirus-specific helper T cell responses in newborns, infants, children, and adults.

    Science.gov (United States)

    Offit, P A; Hoffenberg, E J; Pia, E S; Panackal, P A; Hill, N L

    1992-06-01

    An obstacle to developing a successful rotavirus vaccine has been the inability to consistently correlate the humoral immune response with protection against disease. Transplacental transfer of maternal rotavirus-specific antibodies may obscure the capacity to discriminate an active from a passively acquired humoral immune response in infants. In an attempt to circumvent this problem, an assay was developed to detect rotavirus-specific helper T cells among circulating mononuclear cells. Rotavirus-specific lymphoproliferative responses and rotavirus-specific neutralizing antibody titers in blood were determined in 11 mother/newborn pairs at the time of delivery and in 54 infants, children, and adults ranging in age from 16 days to 40 years. Only 1 of 11 infants tested between 16 days and 6 months of age had detectable rotavirus-specific helper T cell activity whereas 8 of 11 had circulating rotavirus-specific neutralizing antibodies. Acquisition of rotavirus-specific helper T cell activity over the first few years of life correlated with the age at which infants and young children are known to be infected with rotavirus. These findings support the hypothesis that detection of rotavirus-specific lymphoproliferative activity in infants may more accurately determine previous exposure to rotavirus than detection of rotavirus-specific antibodies.

  11. Gamma delta T cell responses associated with the development of tuberculosis in health care workers.

    Science.gov (United States)

    Ordway, Diane J; Pinto, Luisa; Costa, Leonor; Martins, Marta; Leandro, Clara; Viveiros, Miguel; Amaral, Leonard; Arroz, Maria J; Ventura, Fernando A; Dockrell, Hazel M

    2005-03-01

    This study evaluated T cell immune responses to purified protein derivative (PPD) and Mycobacterium tuberculosis (Mtb) in health care workers who remained free of active tuberculosis (HCWs w/o TB), health care workers who went on to develop active TB (HCWs w/TB), non-health care workers who were TB free (Non-HCWs) and tuberculosis patients presenting with minimal (Min TB) or advanced (Adv TB) disease. Peripheral blood mononuclear cells (PBMC) were stimulated with Mtb and PPD and the expression of T cell activation markers CD25+ and HLA-DR+, intracellular IL-4 and IFN-gamma production and cytotoxic responses were evaluated. PBMC from HCWs who developed TB showed decreased percentages of cells expressing CD8+CD25+ in comparison to HCWs who remained healthy. HCWs who developed TB showed increased gammadelta TCR+ cell cytotoxicity and decreased CD3+gammadelta TCR- cell cytotoxicity in comparison to HCWs who remained healthy. PBMC from TB patients with advanced disease showed decreased percentages of CD25+CD4+ and CD25+CD8+ T cells that were associated with increased IL-4 production in CD8+ and gammadelta TCR+ phenotypes, in comparison with TB patients presenting minimal disease. TB patients with advanced disease showed increased gammadelta TCR+ cytotoxicity and reduced CD3+gammadelta TCR- cell cytotoxicity. Our results suggest that HCWs who developed TB show an early compensatory mechanism involving an increase in lytic responses of gammadelta TCR+ cells which did not prevent TB.

  12. Induction of Gag-Specific CD4 T Cell Responses during Acute HIV Infection Is Associated with Improved Viral Control

    Science.gov (United States)

    Schieffer, Miriam; Jessen, Heiko K.; Oster, Alexander F.; Pissani, Franco; Soghoian, Damien Z.; Lu, Richard; Jessen, Arne B.; Zedlack, Carmen; Schultz, Bruce T.; Davis, Isaiah; Ranasinghe, Srinika; Rosenberg, Eric S.; Alter, Galit; Schumann, Ralf R.

    2014-01-01

    ABSTRACT Effector CD4 T cell responses have been shown to be critically involved in the containment and clearance of viral pathogens. However, their involvement in the pathogenesis of HIV infection is less clear, given their additional role as preferred viral targets. We previously demonstrated that the presence of HIV-specific CD4 T cell responses is somewhat associated with HIV control and that specific CD4 T cell functions, such as direct cytolytic activity, can contribute to control of HIV viremia. However, little is known about how the induction of HIV-specific CD4 T cell responses during acute HIV infection influences disease progression and whether responses induced during the early phase of infection are preferentially depleted. We therefore longitudinally assessed, in a cohort of 55 acutely HIV-infected individuals, HIV-specific CD4 T cell responses from acute to chronic infection. Interestingly, we found that the breadth, magnitude, and protein dominance of HIV-specific CD4 T cell responses remained remarkably stable over time. Moreover, we found that the epitopes targeted at a high frequency in acute HIV infection were recognized at the same frequency by HIV-specific CD4 T cells in chronic HIV infection. Interestingly the induction of Gag-specific CD4 T cell responses in acute HIV infection was significantly inversely correlated with viral set point in chronic HIV infection (R = −0.5; P = 0.03), while the cumulative contribution of Env-specific CD4 T cell responses showed the reverse effect. Moreover, individuals with HIV-specific CD4 T cell responses dominantly targeting Gag over Env in acute HIV infection remained off antiretroviral therapy significantly longer (P = 0.03; log rank). Thus, our data suggest that the induction of HIV-specific CD4 T cell responses during acute HIV infection is beneficial overall and does not fuel disease progression. IMPORTANCE CD4 T cells are critical for the clearance and control of viral infections. However, HIV

  13. Differential regulation of T-cell dependent and T-cell independent antibody responses through arginine methyltransferase PRMT1 in vivo.

    Science.gov (United States)

    Hata, Kikumi; Yanase, Noriko; Sudo, Katsuko; Kiyonari, Hiroshi; Mukumoto, Yoshiko; Mizuguchi, Junichiro; Yokosuka, Tadashi

    2016-04-01

    Protein arginine methyltransferase 1 (PRMT1), a major PRMT in mammalian cells, has been shown to play a crucial role in multiple biological functions in vitro. To explore the role of PRMT1 in B cells in vivo, we generated B cell-specific PRMT1-deficient (Prmt1(-/-) ) mice using a Cre-loxP system. Prmt1(-/-) mice showed a defect in B-cell development with diminished levels of serum antibodies. Antibody responses in Prmt1(-/-) mice were absent after stimulation with the type 2 T cell-independent antigen NP-Ficoll but intact after stimulation with the T cell-dependent antigen NP-OVA. Our findings comprise the first evidence showing that PRMT1 is necessary for lymphocyte functions in vivo. © 2016 Federation of European Biochemical Societies.

  14. Bim is required for T-cell allogeneic responses and graft-versus-host disease in vivo

    Science.gov (United States)

    Yu, Yu; Yu, Jing; Iclozan, Cristina; Kaosaard, Kane; Anasetti, Claudio; Yu, Xue-Zhong

    2012-01-01

    Bim, a BH3-only Bcl-2-family protein, is essential for T-cell negative selection in the thymus as well as for the death of activated T cells in the periphery. The role of Bim has been extensively studied in T-cell responses to self-antigens and viral infections. Recent findings on Bim in autoimmunity triggered our interest in investigating whether Bim may play a role in another disease with inflammatory symptoms as graft-versus-host disease (GVHD). Here we report that Bim is required for optimal T-cell responses to alloantigens in vivo and for the development of GVHD. Using murine models of allogeneic bone marrow transplantation (BMT), we found that donor T cells deficient for Bim are impaired in the induction of GVHD primarily due to a significant defect in T cell activation and expansion in vivo. Upon TCR engagement, Bim-/- T cells exhibited selective defects in CD69 expression and phosphorylation of PLCγ1. Our studies uncover a novel aspect of Bim function in T-cell activation with important implications in understanding the mechanisms of T-cell activation and tolerance under allogeneic transplantation. PMID:22432091

  15. Evaluating prediction strategies for identification of T cell responsive mutation-derived neoepitopes in cancer

    DEFF Research Database (Denmark)

    Andersen, Sofie Ramskov; Bjerregaard, Anne-Mette; Fugmann, T.

    2016-01-01

    patients. We investigated the T cell recognition of these personalized peptide libraries using a new technology based on DNA-barcode labeled MHC multimers to detect multiple, potentially > 1000, different neoepitope specific T cell populations in a single sample. Through this unbiased comparison, we......Increasing evidences point to an important role of mutation-derived antigens in immune recognition of cancer. Current strategies for prediction of immunogenic neoepitopes results in large personalized peptide libraries, but only a minority (.... Neoepitopes are of potential valuable as predictors of response to therapy and targets for personalized immunotherapeutic approached. Consequently, there is an unmet need to understand the rules identifying immunogenic neoepitopes. Both tumor mutation mapping via exome sequencing and mass...

  16. Donor exosomes rather than passenger leukocytes initiate alloreactive T cell responses after transplantation

    Science.gov (United States)

    Marino, Jose; Babiker-Mohamed, Mohamed H.; Crosby-Bertorini, Patrick; Paster, Joshua T.; LeGuern, Christian; Germana, Sharon; Abdi, Reza; Uehara, Mayuko; Kim, James I.; Markmann, James F.; Tocco, Georges; Benichou, Gilles

    2016-01-01

    Transplantation of allogeneic organs and tissues represents a lifesaving procedure for a variety of patients affected with end-stage diseases. Although current immunosuppressive therapy prevents early acute rejection, it is associated with nephrotoxicity and increased risks for infection and neoplasia. This stresses the need for selective immune-based therapies relying on manipulation of lymphocyte recognition of donor antigens. The passenger leukocyte theory states that allograft rejection is initiated by recipient T cells recognizing donor major histocompatibility complex (MHC) molecules displayed on graft leukocytes migrating to the host’s lymphoid organs. We revisited this concept in mice transplanted with allogeneic skin, heart, or islet grafts using imaging flow cytometry. We observed no donor cells in the lymph nodes and spleen of skin-grafted mice, but we found high numbers of recipient cells displaying allogeneic MHC molecules (cross-dressed) acquired from donor microvesicles (exosomes). After heart or islet transplantation, we observed few donor leukocytes (100 per million) but large numbers of recipient cells cross-dressed with donor MHC (>90,000 per million). Last, we showed that purified allogeneic exosomes induced proinflammatory alloimmune responses by T cells in vitro and in vivo. Collectively, these results suggest that recipient antigen-presenting cells cross-dressed with donor MHC rather than passenger leukocytes trigger T cell responses after allotransplantation. PMID:27942611

  17. Quantitative imaging of the T cell antitumor response by positron-emission tomography

    Science.gov (United States)

    Dubey, Purnima; Su, Helen; Adonai, Nona; Du, Shouying; Rosato, Antonio; Braun, Jonathan; Gambhir, Sanjiv S.; Witte, Owen N.

    2003-02-01

    We describe a noninvasive, quantitative, and tomographic method to visualize lymphocytes within the whole animal. We used positron-emission tomography (PET) to follow the localization of adoptively transferred immune T lymphocytes. Splenic T cells from animals that had rejected a Moloney murine sarcoma virus/Moloney murine leukemia virus (M-MSV/M-MuLV)-induced tumor were marked with a PET reporter gene, injected into tumor-bearing mice, and imaged in a microPET by using a substrate specific for the reporter. Specific localization of immune T cells to the antigen-positive tumor was detected over time, by sequential imaging of the same animals. Naive T cells did not localize to the tumor site, indicating that preimmunization was required. Autoradiography and immunohistochemistry analysis corroborated the microPET data. The method we have developed can be used to assess the effects of immunomodulatory agents intended to potentiate the immune response to cancer, and can also be useful for the study of other cell-mediated immune responses, including autoimmunity.

  18. Elevated and cross-responsive CD1a-reactive T cells in bee and wasp venom allergic individuals.

    Science.gov (United States)

    Subramaniam, Sumithra; Aslam, Aamir; Misbah, Siraj A; Salio, Mariolina; Cerundolo, Vincenzo; Moody, D Branch; Ogg, Graham

    2016-01-01

    The role of CD1a-reactive T cells in human allergic disease is unknown. We have previously shown that circulating CD1a-reactive T cells recognize neolipid antigens generated by bee and wasp venom phospholipase, and here tested the hypothesis that venom-responsive CD1a-reactive T cells associate with venom allergy. Circulating T cells from bee and wasp venom allergic individuals, before and during immunotherapy, were exposed to CD1a-transfected K562 cells in the presence of wasp or bee venom. T-cell response was evaluated based on IFNγ, GM-CSF, and IL-13 cytokine production. Venom allergic individuals showed significantly higher frequencies of IFN-γ, GM-CSF, and IL-13 producing CD1a-reactive T cells responsive to venom and venom-derived phospholipase than healthy individuals. Venom-responsive CD1a-reactive T cells were cross-responsive between wasp and bee suggesting shared pathways of allergenicity. Frequencies of CD1a-reactive T cells were initially induced during subcutaneous immunotherapy, peaking by weeks 5, but then reduced despite escalation of antigen dose. Our current understanding of venom allergy and immunotherapy is largely based on peptide and protein-specific T cell and antibody responses. Here, we show that lipid antigens and CD1a-reactive T cells associate with the allergic response. These data have implications for mechanisms of allergy and approaches to immunotherapy. © 2015 The Authors. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Multifunctional Analysis of CD4+ T-Cell Response as Immune-Based Model for Tuberculosis Detection

    Directory of Open Access Journals (Sweden)

    Miriam Lichtner

    2015-01-01

    Full Text Available Mono- and multifunctional specific CD4+ and CD8+ T-cell responses were evaluated to improve the immune-based detection of active tuberculosis (TB and latent infection (LTBI. We applied flow cytometry to investigate cytokines profile (IFN-γ, TNF-α, and IL-2 of T cells after stimulation with TB antigens in 28 TB-infected subjects (18 active TB and 10 LTBI and 10 uninfected controls. Cytokines production by CD4+ T cells at single-cell levels was higher in TB-infected subjects than uninfected controls P0.45%, it was possible to differentiate TB-infected (>0.45% by uninfected subjects (0.182%. The magnitude of CD8+ T-cell responses showed no differences between active TB and LTBI. Multifunctional CD4+ T-cell responses could have the potential to identify at single time point subjects without TB infection and patients having active or latent TB.

  20. The Yin and Yang aspects of IL-27 in induction of cancer-specific T-cell responses and immunotherapy.

    Science.gov (United States)

    Li, Ming-Song; Liu, Zhenzhen; Liu, Jin-Qing; Zhu, Xiaotong; Liu, Zhihao; Bai, Xue-Feng

    2015-01-01

    Accumulating evidences from animal studies have indicated that both endogenous and exogenous IL-27, an IL-12 family of cytokine, can increase antitumor T-cell activities and inhibit tumor growth. IL-27 can modulate Treg responses, and program effector T cells into a unique T-effector stem cell (TSEC) phenotype, which enhances T-cell survival in the tumor microenvironment. However, animal studies also suggest that IL-27 induces molecular pathways such as IL-10, PD-L1 and CD39, which may downregulate tumor-specific T-cell responses. In this review paper, we will discuss the Yin and Yang aspects of IL-27 in the induction of tumor-specific T-cell responses, and the potential impacts of these functions of IL-27 in the design of cancer immunotherapy.

  1. Polyfunctional cytokine production by central memory T cells from cattle in response to Mycobacterium bovis infection and BCG vaccination

    Science.gov (United States)

    Polyfunctional T cells simultaneously produce IFN-gamma, IL-2 and TNF-alpha and play relevant roles in several chronic infections, including TB. Mycobacterium bovis infection of cattle elicits ex vivo polyfunctional T cell responses. Vaccine-elicited IFN-gamma Tcm (CD4 plus CD45RO plus CCR7 plus) re...

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

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    Rudragouda Channappanavar

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

  3. Opposite effects of total lymphoid irradiation on T cell-dependent and T cell-independent antibody responses

    Energy Technology Data Exchange (ETDEWEB)

    Tanay, A.; Strober, S.

    1984-02-01

    The effect of total lymphoid irradiation (TLI) on the primary antibody response to the dinitrophenylated heterologous protein, keyhole limpet hemocyanin (DNP-KLH), in complete Freund's adjuvant (CFA), and to the trinitrophenylated polysaccharide antigen, Brucella abortus (TNP-BA), was studied in BALB/c mice. The antibody response to both antigens was diminished in comparison with nonirradiated mice when antigens were injected within 3 days after TLI. When the mice were immunized 30 days after completion of TLI the antibody response to DNP-KLH in CFA was still diminished, but the antibody response to TNP-BA was enhanced 5- to 10-fold as compared with that of control animals. The opposite effect of TLI on the two antibody responses was also observed in a syngeneic primary adoptive transfer system.

  4. Distinctive in vitro effects of T-cell growth cytokines on cytomegalovirus-stimulated T-cell responses of HIV-infected HAART recipients

    International Nuclear Information System (INIS)

    Patterson, Julie; Jesser, Renee; Weinberg, Adriana

    2008-01-01

    Functional immune reconstitution is limited after HAART, maintaining the interest in adjunctive immune-modulators. We compared in vitro the effects of the γ-chain T-cell growth cytokines IL-2, IL-4, IL-7 and IL-15 on cytomegalovirus-stimulated cell-mediated immunity. IL-2 and IL-15 increased cytomegalovirus-specific lymphocyte proliferation in HAART recipients, whereas IL-4 and IL-7 did not. The boosting effect of IL-2 and IL-15 on proliferation correlated with their ability to prevent late apoptosis. However, IL-2 increased the frequency of cells in early apoptosis, whereas IL-15 increased the frequency of fully viable cells. Both IL-2 and IL-15 increased cytomegalovirus-induced CD4 + and CD8 + T-cell proliferation and the synthesis of Th1 and pro-inflammatory cytokines and chemokines. However, only IL-2 increased the frequency of regulatory T cells and Th2 cytokine production, both of which have the potential to attenuate antiviral immune responses. Overall, compared to other γ-chain cytokines, IL-15 had the most favorable profile for boosting antiviral cell-mediated immunity

  5. Salmonella polarises peptide-MHC-II presentation towards an unconventional Type B CD4+ T-cell response.

    Science.gov (United States)

    Jackson, Nicola P; Kang, Yu Hui; Lapaque, Nicolas; Janssen, Hans; Trowsdale, John; Kelly, Adrian P

    2013-04-01

    Distinct peptide-MHC-II complexes, recognised by Type A and B CD4(+) T-cell subsets, are generated when antigen is loaded in different intracellular compartments. Conventional Type A T cells recognize their peptide epitope regardless of the route of processing, whereas unconventional Type B T cells only recognise exogenously supplied peptide. Type B T cells are implicated in autoimmune conditions and may break tolerance by escaping negative selection. Here we show that Salmonella differentially influences presentation of antigen to Type A and B T cells. Infection of bone marrow-derived dendritic cells (BMDCs) with Salmonella enterica serovar Typhimurium (S. Typhimurium) reduced presentation of antigen to Type A T cells but enhanced presentation of exogenous peptide to Type B T cells. Exposure to S. Typhimurium was sufficient to enhance Type B T-cell activation. Salmonella Typhimurium infection reduced surface expression of MHC-II, by an invariant chain-independent trafficking mechanism, resulting in accumulation of MHC-II in multi-vesicular bodies. Reduced MHC-II surface expression in S. Typhimurium-infected BMDCs correlated with reduced antigen presentation to Type A T cells. Salmonella infection is implicated in reactive arthritis. Therefore, polarisation of antigen presentation towards a Type B response by Salmonella may be a predisposing factor in autoimmune conditions such as reactive arthritis. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Immune Responses to Dengue and Zika Viruses—Guidance for T Cell Vaccine Development

    Directory of Open Access Journals (Sweden)

    Claude Roth

    2018-02-01

    Full Text Available Despite numerous efforts to identify the molecular and cellular effectors of the adaptive immunity that induce a long-lasting immunity against dengue or Zika virus infection, the specific mechanisms underlying such protective immunity remain largely unknown. One of the major challenges lies in the high level of dengue virus (DENV seroprevalence in areas where Zika virus (ZIKV is circulating. In the context of such a pre-existing DENV immunity that can exacerbate ZIKV infection and disease, and given the lack of appropriate treatment for ZIKV infection, there is an urgent need to develop an efficient vaccine against DENV and ZIKV. Notably, whereas several ZIKV vaccine candidates are currently in clinical trials, all these vaccine candidates have been designed to induce neutralizing antibodies as the primary mechanism of immune protection. Given the difficulty to elicit simultaneously high levels of neutralizing antibodies against the different DENV serotypes, and the potential impact of pre-existing subneutralizing antibodies induced upon DENV infection or vaccination on ZIKV infection and disease, additional or alternative strategies to enhance vaccine efficacy, through T cell immunity, are now being considered. In this review, we summarize recent discoveries about cross-reactive B and T cell responses against DENV and ZIKV and propose guidelines for the development of safe and efficient T cell vaccines targeting both viruses.

  7. Regulatory T cells in the humoral response of protein deficient mice.

    Science.gov (United States)

    Price, P; Turner, K J

    1979-01-01

    Cell suspensions from the spleen or thymus of mice fed normally or mice that were protein deficient were injected into mice from each dietary group and also syngeneic nudes. Antigen, polyvinyl pyrrolidone (PVP), was injected at the stage of cell transfer and the antibody titres of the recipient animals were compared with those of control animals given only antigen. The regime was repeated using cell suspensions from donor animals which had been primed with antigen. These experiments showed that spleen cells were suppressive only when transferred from deficient to normal mice. Thymocytes generally lacked suppressive effects, except when given to irradiated mice also injected with "normal" spleen cells. However, thymocytes from deficient mice were marginally enhancing in nude mice, deficient mice and older "normals". To explain these results, it is suggested that responses to PVP are determined by distinct "suppressor-inducing" and "suppressor" T cells which act via helper T cells. The latter probably affect B cells directly and largely influence IgG production. It also appears likely that the ratio of helper to suppressor (inducer and effector) T cells is increased by protein deficiency.

  8. Responsiveness of T cells to interleukin-7 is associated with higher CD4+ T cell counts in HIV-1-positive individuals with highly active antiretroviral therapy-induced viral load suppression.

    Science.gov (United States)

    Camargo, Jose F; Kulkarni, Hemant; Agan, Brian K; Gaitan, Alvaro A; Beachy, Lisa A; Srinivas, Sowmya; He, Weijing; Anderson, Stephanie; Marconi, Vincent C; Dolan, Matthew J; Ahuja, Sunil K

    2009-06-15

    Despite suppression of the human immunodeficiency virus type 1 (HIV-1) load by highly active antiretroviral therapy (HAART), recovery of CD4+ T cell counts can be impaired. We investigated whether this impairment may be associated with hyporesponsiveness of T cells to gamma-chain (gammac) cytokines known to influence T cell homeostasis. The responsiveness of T cells to interleukin (IL)-2, IL-7, and IL-15 was determined by assessing cytokine-induced phosphorylation of the signal transducer and activator of transcription 5 (STAT5) in peripheral T cells obtained from 118 HIV-positive subjects and 13 HIV-negative subjects. The responsiveness of T cells to interleukin (IL)-7 but not to IL-2 or IL-15 was lower among HIV-positive subjects than among HIV-negative subjects. Among subjects with viral load suppression, the degree of IL-7 responsiveness (1) correlated with naive CD4+ T cell counts and was a better immune correlate of the prevailing CD4+ T cell count than were levels of human leukocyte antigen-DR1 or programmed death-1, which are predictors of T cell homeostasis during HIV infection; and (2) was greater in subjects with complete (i.e., attainment of >or=500 CD4+ T cells/mm3>or=5 years after initiation of HAART) versus incomplete immunologic responses. The correlation between plasma levels of IL-7 and CD4+ T cell counts during HAART was maximal in subjects with increased IL-7 responsiveness. Responsiveness of T cells to IL-7 is associated with higher CD4+ T cell counts during HAART and thus may be a determinant of the extent of immune reconstitution.

  9. Transamidation of wheat flour inhibits the response to gliadin of intestinal T cells in celiac disease.

    Science.gov (United States)

    Gianfrani, Carmen; Siciliano, Rosa A; Facchiano, Angelo M; Camarca, Alessandra; Mazzeo, Maria F; Costantini, Susan; Salvati, Virginia M; Maurano, Francesco; Mazzarella, Giuseppe; Iaquinto, Gaetano; Bergamo, Paolo; Rossi, Mauro

    2007-09-01

    Celiac disease is characterized by activation of HLA-DQ2/DQ8-restricted intestinal gluten-specific CD4(+) T cells. In particular, gluten becomes a better T-cell antigen following deamidation catalyzed by tissue transglutaminase. To date, the only available therapy is represented by adherence to a gluten-free diet. Here, we examined a new enzyme strategy to preventively abolish gluten activity. Enzyme modifications of the immunodominant alpha-gliadin peptide p56-68 were analyzed by mass spectrometry, and peptide binding to HLA-DQ2 was simulated by modeling studies. Wheat flour was treated with microbial transglutaminase and lysine methyl ester; gliadin was subsequently extracted, digested, and deamidated. Gliadin-specific intestinal T-cell lines (iTCLs) were generated from biopsy specimens from 12 adult patients with celiac disease and challenged in vitro with different antigen preparations. Tissue transglutaminase-mediated transamidation with lysine or lysine methyl ester of p56-68 or gliadin in alkaline conditions inhibited the interferon gamma expression in iTCLs; also, binding to DQ2 was reduced but not abolished, as suggested by in silico analysis. Lysine methyl ester was particularly effective in abrogating the activity of gliadin. Notably, a block in the response was observed when iTCLs were challenged with gliadin extracted from flour pretreated with microbial transglutaminase and lysine methyl ester. Transamidation of wheat flour with a food-grade enzyme and an appropriate amine donor can be used to block the T cell-mediated gliadin activity. Considering the crucial role of adaptive immunity in celiac disease, our findings highlight the potential of the proposed treatment to prevent cereal toxicity.

  10. Interdisciplinary Evaluation of Broadly-Reactive HLA Class II Restricted Epitopes Eliciting HIV-Specific CD4+T Cell Responses

    DEFF Research Database (Denmark)

    Buggert, M.; Norström, M.; Lundegaard, Claus

    2011-01-01

    bioinformatic prediction program NetMHCIIpan to select 64 optimized MHC II restricted epitopes located in the HIV Gag, Pol, Env, Nef and Tat regions. The epitopes were selected to cover the global diversity of the virus (multiple subtypes) and the human immune system(diverse MHC II types). Optimized......Background: CD4+ T cells orchestrate immune protection by ‘‘helping’’ other cells of our immune system to clear viral infections. It is well known that the preferential infection and depletion of CD4+ T cells contributes to hampered systemic T cell help following HIV infection. However......, the functional and immunodominant discrepancies of CD4+ T cell responses targeting promiscuous MHC II restricted HIV epitopes remains poorly defined. Thus, utilization of interdisciplinary approaches might aid revealing broadly- reactive peptides eliciting CD4 + T cell responses. Methods: We utilized the novel...

  11. Induction of CD8+ T-cell responses against subunit antigens by the novel cationic liposomal CAF09 adjuvant

    DEFF Research Database (Denmark)

    Korsholm, Karen Smith; Hansen, Jon; Karlsen, Kasper

    2014-01-01

    Vaccines inducing cytotoxic T-cell responses are required to achieve protection against cancers and intracellular infections such as HIV and Hepatitis C virus. Induction of CD8+ T cell responses in animal models can be achieved by the use of viral vectors or DNA vaccines but so far without much...... clinical success. Here we describe the novel CD8+ T-cell inducing adjuvant, cationic adjuvant formulation (CAF) 09, consisting of dimethyldioctadecylammonium (DDA)-liposomes stabilized with monomycoloyl glycerol (MMG)-1 and combined with the TLR3 ligand, Poly(I:C). Different antigens from tuberculosis (TB......10.3, H56), HIV (Gag p24), HPV (E7) and the model antigen ovalbumin were formulated with CAF09 and administering these vaccines to mice resulted in a high frequency of antigen-specific CD8+ T cells. CAF09 was superior in its ability to induce antigen-specific CD8+ T cells as compared to other...

  12. The CD8 and CD4 T-cell response against Kaposi's sarcoma-associated herpesvirus is skewed towards early and late lytic antigens.

    Directory of Open Access Journals (Sweden)

    Rebecca C Robey

    Full Text Available Kaposi's sarcoma-associated herpesvirus (KSHV is causally related to Kaposi's sarcoma (KS, the most common malignancy in untreated individuals with HIV/AIDS. The adaptive T-cell immune response against KSHV has not been fully characterized. To achieve a better understanding of the antigenic repertoire of the CD8 and CD4 T-cell responses against KSHV, we constructed a library of lentiviral expression vectors each coding for one of 31 individual KSHV open reading frames (ORFs. We used these to transduce monocyte-derived dendritic cells (moDCs isolated from 14 KSHV-seropositive (12 HIV-positive and 7 KSHV-seronegative (4 HIV-positive individuals. moDCs were transduced with up to 3 KSHV ORFs simultaneously (ORFs grouped according to their expression during the viral life cycle. Transduced moDCs naturally process the KSHV genes and present the resulting antigens in the context of MHC class I and II. Transduced moDCs were cultured with purified autologous T cells and the CD8 and CD4 T-cell proliferative responses to each KSHV ORF (or group was assessed using a CFSE dye-based assay. Two pools of early lytic KSHV genes ([ORF8/ORF49/ORF61] and [ORF59/ORF65/K4.1] were frequently-recognized targets of both CD8 and CD4 T cells from KSHV seropositive individuals. One pool of late lytic KSHV genes ([ORF28/ORF36/ORF37] was a frequently-recognized CD8 target and another pool of late genes ([ORF33/K1/K8.1] was a frequently-recognized CD4 target. We report that both the CD8 and CD4 T-cell responses against KSHV are skewed towards genes expressed in the early and late phases of the viral lytic cycle, and identify some previously unknown targets of these responses. This knowledge will be important to future immunological investigations into KSHV and may eventually lead to the development of better immunotherapies for KSHV-related diseases.

  13. T Cell Factor 1-Expressing Memory-like CD8(+) T Cells Sustain the Immune Response to Chronic Viral Infections.

    Science.gov (United States)

    Utzschneider, Daniel T; Charmoy, Mélanie; Chennupati, Vijaykumar; Pousse, Laurène; Ferreira, Daniela Pais; Calderon-Copete, Sandra; Danilo, Maxime; Alfei, Francesca; Hofmann, Maike; Wieland, Dominik; Pradervand, Sylvain; Thimme, Robert; Zehn, Dietmar; Held, Werner

    2016-08-16

    Chronic infections promote the terminal differentiation (or "exhaustion") of T cells and are thought to preclude the formation of memory T cells. In contrast, we discovered a small subpopulation of virus-specific CD8(+) T cells that sustained the T cell response during chronic infections. These cells were defined by, and depended on, the expression of the transcription factor Tcf1. Transcriptome analysis revealed that this population shared key characteristics of central memory cells but lacked an effector signature. Unlike conventional memory cells, Tcf1-expressing T cells displayed hallmarks of an "exhausted" phenotype, including the expression of inhibitory receptors such as PD-1 and Lag-3. This population was crucial for the T cell expansion that occurred in response to inhibitory receptor blockade during chronic infection. These findings identify a memory-like T cell population that sustains T cell responses and is a prime target for therapeutic interventions to improve the immune response in chronic infections. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Responses of Bovine WC1+ γδ T Cells to Protein and Nonprotein Antigens of Mycobacterium bovis

    Science.gov (United States)

    Welsh, Michael D.; Kennedy, Hilary E.; Smyth, Allister J.; Girvin, R. Martyn; Andersen, Peter; Pollock, John M.

    2002-01-01

    WC1+ γδ T cells of Mycobacterium bovis-infected cattle are highly responsive to M. bovis sonic extract (MBSE). In mycobacterial infections of other species, γδ T cells have been shown to respond to protein and nonprotein antigens, but the bovine WC1+ γδ T-cell antigenic targets within MBSE require further definition in terms of the dominance of protein versus nonprotein components. The present study sought to characterize the WC1+ γδ T-cell antigenic targets, together with the role of interleukin-2 (IL-2), in the context of M. bovis infection. This was achieved by testing crude and defined antigens to assess protein versus nonprotein recognition by WC1+ γδ T cells in comparison with CD4+ αβ T cells. Both cell types proliferated strongly in response to MBSE, with CD4+ T cells being the major producers of gamma interferon (IFN-γ). However, enzymatic digestion of the protein in MBSE removed its ability to stimulate CD4+ T-cell responses, whereas some WC1+ γδ T-cell proliferation remained. The most antigenic protein inducing proliferation and IFN-γ secretion in WC1+ γδ T-cell cultures was found to be ESAT-6, which is a potential novel diagnostic reagent and vaccine candidate. In addition, WC1+ γδ T-cell proliferation was observed in response to stimulation with prenyl pyrophosphate antigens (isopentenyl pyrophosphate and monomethyl phosphate). High levels of cellular activation (CD25 expression) resulted from MBSE stimulation of WC1+ γδ T cells from infected animals. A similar degree of activation was induced by IL-2 alone, but for WC1+ γδ T-cell division IL-2 was found to act only as a costimulatory signal, enhancing antigen-driven responses. Overall, the data indicate that protein antigens are important stimulators of WC1+ γδ T-cell proliferation and IFN-γ secretion in M. bovis infection, with nonprotein antigens inducing significant proliferation. These findings have important implications for diagnostic and vaccine development. PMID

  15. Aqueous exposure to Aroclor 1254 modulates the mitogenic response of Atlantic salmon anterior kidney T-cells: Indications of short- and long-term immunomodulation

    Energy Technology Data Exchange (ETDEWEB)

    Iwanowicz, Luke R. [Department of Natural Resources Conservation, University of Massachusetts, Amherst, MA 01003 (United States) and USGS, Leetown Science Center, National Fish Health Research Laboratory, Kearneysville, WV 25430 (United States)]. E-mail: luke_iwanowicz@usgs.gov; Lerner, Darren T. [Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003 (United States); Blazer, Vicki S. [USGS, Leetown Science Center, National Fish Health Research Laboratory, Kearneysville, WV 25430 (United States); McCormick, Stephen D. [Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003 (United States); USGS, Leetown Science Center, Conte Anadromous Fish Research Center, Turners Falls, MA 01376 (United States)

    2005-05-15

    Polychlorinated biphenyls (PCBs) exist as persistent organic pollutants in numerous river systems in the United States. Unfortunately, some of these rivers are sites of active Atlantic salmon restoration programs, and polychlorinated biphenyls have been implicated as ancillary factors contributing to failed salmon restoration. Here, we investigate the immediate and chronic effects of intermediate duration aqueous PCB exposure (1 or 10 {mu}g L{sup -1} Aroclor 1254) on the mitogen-stimulated lymphoproliferative response of Atlantic salmon anterior kidney leukocytes (AKLs). A short-term study was designed to examine immunomodulation in Atlantic salmon smolts immediately following 21 days of aqueous exposure, while a long-term study evaluated chronic impacts in the mitogen response in parr 15 months post-exposure as larvae. The proliferative response of AKLs to the mitogens concanavalin A (CON A), phytohemaglutinnin-P (PHA-P), pokeweed mitogen (PWM), and lipopolysaccharide were used as an indice of immunomodulation. The proliferative response to the T-cell mitogens CON A and PHA-P was significantly increased in the 10 {mu}g L{sup -1} group (n = 10; P = 0.043 and 0.002, respectively) immediately following exposure of smolts. Additionally, The PHA-P response was significantly increased in the 1 {mu}g L{sup -1} exposure group (n = 10, P = 0.036). In fish treated as larvae and tested 15 months later, the PHA-P sensitive populations exhibited elevated proliferation in the 1 and 10 {mu}g L{sup -1} groups (n = 12, P < 0.04) relative to the vehicle control while the PWM response was significantly increased (n = 12, P 0.036) only in the 10 {mu}g L{sup -1} treated groups. These results demonstrate an immunomodulatory effect of PCBs on T-cell mitogen sensitive populations of lymphocytes in Atlantic salmon as well as long-term immunomodulation in PHA-P and PWM sensitive populations.

  16. T-cell responses against Malaria: Effect of parasite antigen diversity and relevance for vaccine development.

    Science.gov (United States)

    Nlinwe, Omarine Nfor; Kusi, Kwadwo Asamoah; Adu, Bright; Sedegah, Martha

    2018-03-21

    The on-going agenda for global malaria elimination will require the development of additional disease control and prevention measures since currently available tools are showing signs of inadequacy. Malaria vaccines are seen as one such important addition to the control arsenal since vaccines have proven to be highly effective public health tools against important human diseases. Both cell-mediated and antibody responses are generally believed to be important for malaria parasite control, although the exact targets of T and B cell responses against malaria have not been clearly defined. However, our current understanding of the immune response to malaria suggests that T cell responses against multiple antigenic targets may potentially be key for the development of a highly efficacious malaria vaccine. This review takes a comprehensive look at the available literature on T cell-mediated immunity against all human stages of the malaria parasite and the effect of antigen diversity on these responses. The implications of these interrelationships for the development of an effective vaccine for malaria are also highlighted. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Persistence of mucosal T-cell responses to herpes simplex virus type 2 in the female genital tract.

    Science.gov (United States)

    Posavad, C M; Zhao, L; Mueller, D E; Stevens, C E; Huang, M L; Wald, A; Corey, L

    2015-01-01

    Relatively little is known about the human T-cell response to herpes simplex virus type 2 (HSV-2) in the female genital tract, a major site of heterosexual HSV-2 acquisition, transmission, and reactivation. In order to understand the role of local mucosal immunity in HSV-2 infection, T-cell lines were expanded from serial cervical cytobrush samples from 30 HSV-2-infected women and examined for reactivity to HSV-2. Approximately 3% of the CD3+ T cells isolated from the cervix were HSV-2 specific and of these, a median of 91.3% were CD4+, whereas a median of 3.9% were CD8+. HSV-2-specific CD4+ T cells expanded from the cervix were not only more frequent than CD8+ T cells but also exhibited greater breadth in terms of antigenic reactivity. T cells directed at the same HSV-2 protein were often detected in serial cervical cytobrush samples and in blood. Thus, broad and persistent mucosal T-cell responses to HSV-2 were detected in the female genital tract of HSV-2+ women suggesting that these cells are resident at the site of HSV-2 infection. Understanding the role of these T cells at this biologically relevant site will be central to the elucidation of adaptive immune mechanisms involved in controlling HSV-2 disease.

  18. Antibody and T cell responses to Fusobacterium nucleatum and Treponema denticola in health and chronic periodontitis.

    Directory of Open Access Journals (Sweden)

    Jieun Shin

    Full Text Available The characteristics of the T cell response to the members of oral flora are poorly understood. We characterized the antibody and T cell responses to FadA and Td92, adhesins from Fusobacterium nucleatum, an oral commensal, and Treponema denticola, a periodontal pathogen, respectively. Peripheral blood and saliva were obtained from healthy individuals and patients with untreated chronic periodontitis (CP, n = 11 paris and after successful treatment of the disease (n = 9. The levels of antigen-specific antibody were measured by ELISA. In plasma, IgG1 was the most abundant isotype of Ab for both Ags, followed by IgA and then IgG4. The levels of FadA-specific salivary IgA (sIgA were higher than Td92-specific sIgA and the FadA-specific IgA levels observed in plasma. However, the periodontal health status of the individuals did not affect the levels of FadA- or Td92-specific antibody. Even healthy individuals contained FadA- and Td92-specific CD4(+ T cells, as determined by the detection of intracytoplasmic CD154 after short-term in vitro stimulation of peripheral blood mononuclear cells (PBMCs with the antigens. Patients with CP tended to possess increased numbers of FadA- and Td92-specific CD4(+ T cells but reduced numbers of Td92-specific Foxp3(+CD4(+ Tregs than the healthy subjects. Both FadA and Td92 induced the production of IFNγ and IL-10 but inhibited the secretion of IL-4 by PBMCs. In conclusion, F. nucleatum induced Th3 (sIgA- and Th1 (IFNγ and IgG1-dominant immune responses, whereas T. denticola induced a Th1 (IFNγ and IgG1-dominant response. This IFNγ-dominant cytokine response was impaired in CP patients, and the Td92-induced IFNγ levels were negatively associated with periodontal destruction in patients. These findings may provide new insights into the homeostatic interaction between the immune system and oral bacteria and the pathogenesis of periodontitis.

  19. Impact of Chronic Viral Infection on T-Cell Dependent Humoral Immune Response

    Directory of Open Access Journals (Sweden)

    Stéphane Rodriguez

    2017-10-01

    Full Text Available During the last decades, considerable efforts have been done to decipher mechanisms supported by microorganisms or viruses involved in the development, differentiation, and function of immune cells. Pathogens and their associated secretome as well as the continuous inflammation observed in chronic infection are shaping both innate and adaptive immunity. Secondary lymphoid organs are functional structures ensuring the mounting of adaptive immune response against microorganisms and viruses. Inside these organs, germinal centers (GCs are the specialized sites where mature B-cell differentiation occurs leading to the release of high-affinity immunoglobulin (Ig-secreting cells. Different steps are critical to complete B-cell differentiation process, including proliferation, somatic hypermutations in Ig variable genes, affinity-based selection, and class switch recombination. All these steps require intense interactions with cognate CD4+ helper T cells belonging to follicular helper lineage. Interestingly, pathogens can disturb this subtle machinery affecting the classical adaptive immune response. In this review, we describe how viruses could act directly on GC B cells, either through B-cell infection or by their contribution to B-cell cancer development and maintenance. In addition, we depict the indirect impact of viruses on B-cell response through infection of GC T cells and stromal cells, leading to immune response modulation.

  20. Immune response of T cells during herpes simplex virus type 1 (HSV-1) infection.

    Science.gov (United States)

    Zhang, Jie; Liu, Huan; Wei, Bin

    Herpes simplex virus type 1 (HSV-1), a neurotropic member of the alphaherpes virus family, is among the most prevalent and successful human pathogens. HSV-1 can cause serious diseases at every stage of life including fatal disseminated disease in newborns, cold sores, eye disease, and fatal encephalitis in adults. HSV-1 infection can trigger rapid immune responses, and efficient inhibition and clearance of HSV-1 infection rely on both the innate and adaptive immune responses of the host. Multiple strategies have been used to restrict host innate immune responses by HSV-1 to facilitate its infection in host cells. The adaptive immunity of the host plays an important role in inhibiting HSV-1 infections. The activation and regulation of T cells are the important aspects of the adaptive immunity. They play a crucial role in host-mediated immunity and are important for clearing HSV-1. In this review, we examine the findings on T cell immune responses during HSV-1 infection, which hold promise in the design of new vaccine candidates for HSV-1.

  1. Transient decomplementation of mice delays onset of experimental autoimmune encephalomyelitis and impairs MOG-specific T cell response and autoantibody production.

    Science.gov (United States)

    Terényi, Nóra; Nagy, Nándor; Papp, Krisztián; Prechl, József; Oláh, Imre; Erdei, Anna

    2009-11-01

    Multiple sclerosis (MS) is the most common inflammatory and demyelinating disease of the central nervous system. In both MS and its animal model experimental autoimmune encephalomyelitis (EAE), it is thought that infiltrating CD4(+) T cells initiate an inflammatory process and collect other immune effectors to mediate tissue damage. The pathophysiology of the disease however remains unclear. Here we focus on the role of the complement system in the pathomechanism of EAE, employing mice with transiently depleted complement activity achieved by a single injection of cobra venom factor (CVF) 2 days before the induction of the disease. Our results show that in decomplemented C57BL/6 mice immunized with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55, the onset of the disease is significantly delayed. In SJL/J mice which develop a relapsing-remitting form of EAE after injection with proteolipid protein (PLP) peptide 139-151, the attenuation of both phases could be observed in CVF-treated animals. In C57BL/6 mice the level of MOG specific autoantibodies and their complement activating capacity evaluated on day 21 were found significantly reduced in animals transiently decomplemented before induction of the disease. The in vitro response of T cells isolated from the lymph nodes of MOG-immunized animals at the onset of EAE was also investigated. We found that the proliferative capacity of MOG-specific T lymphocytes derived from CVF treated animals is significantly reduced, in agreement with the histology of the spinal cords showing a decreased infiltration of CD4(+) T cells in these mice. Our data suggest, that lack of systemic complement at the time of induction of EAE delays the onset and attenuates the course of the disease most probably via diminishing the response of MOG-specific T cells and production of autoantibodies.

  2. T Cell Epitope-Containing Domains of Ragweed Amb a 1 and Mugwort Art v 6 Modulate Immunologic Responses in Humans and Mice.

    Science.gov (United States)

    Sancho, Ana I; Wallner, Michael; Hauser, Michael; Nagl, Birgit; Himly, Martin; Asam, Claudia; Ebner, Christof; Jahn-Schmid, Beatrice; Bohle, Barbara; Ferreira, Fatima

    2017-01-01

    Ragweed (Ambrosia artemisiifolia) and mugwort (Artemisia vulgaris) are the major cause of pollen allergy in late summer. Allergen-specific lymphocytes are crucial for immune modulation during immunotherapy. We sought to generate and pre-clinically characterise highly immunogenic domains of the homologous pectate lyases in ragweed (Amb a 1) and mugwort pollen (Art v 6) for immunotherapy. Domains of Amb a 1 (Amb a 1α) and Art v 6 (Art v 6α) and a hybrid molecule, consisting of both domains, were designed, expressed in E. coli and purified. Human IgE reactivity and allergenicity were assessed by ELISA and mediator release experiments using ragweed and mugwort allergic patients. Moreover, T cell proliferation was determined. Blocking IgG antibodies and cytokine production in BALB/c mice were studied by ELISA and ELISPOT. The IgE binding capacity and in vitro allergenic activity of the Amb a 1 and Art v 6 domains and the hybrid were either greatly reduced or abolished. The recombinant proteins induced T cell proliferative responses comparable to those of the natural allergens, indicative of retained allergen-specific T cell response. Mice immunisation with the hypoallergens induced IL-4, IL-5, IL-13 and IFN-γ production after antigen-specific in vitro re-stimulation of splenocytes. Moreover, murine IgG antibodies that inhibited specific IgE binding of ragweed and mugwort pollen allergic patients were detected. Accumulation of T cell epitopes and deletion of IgE reactive areas of Amb a 1 and Art v 6, modulated the immunologic properties of the allergen immuno-domains, leading to promising novel candidates for therapeutic approach.

  3. T Cell Epitope-Containing Domains of Ragweed Amb a 1 and Mugwort Art v 6 Modulate Immunologic Responses in Humans and Mice.

    Directory of Open Access Journals (Sweden)

    Ana I Sancho

    Full Text Available Ragweed (Ambrosia artemisiifolia and mugwort (Artemisia vulgaris are the major cause of pollen allergy in late summer. Allergen-specific lymphocytes are crucial for immune modulation during immunotherapy. We sought to generate and pre-clinically characterise highly immunogenic domains of the homologous pectate lyases in ragweed (Amb a 1 and mugwort pollen (Art v 6 for immunotherapy.Domains of Amb a 1 (Amb a 1α and Art v 6 (Art v 6α and a hybrid molecule, consisting of both domains, were designed, expressed in E. coli and purified. Human IgE reactivity and allergenicity were assessed by ELISA and mediator release experiments using ragweed and mugwort allergic patients. Moreover, T cell proliferation was determined. Blocking IgG antibodies and cytokine production in BALB/c mice were studied by ELISA and ELISPOT.The IgE binding capacity and in vitro allergenic activity of the Amb a 1 and Art v 6 domains and the hybrid were either greatly reduced or abolished. The recombinant proteins induced T cell proliferative responses comparable to those of the natural allergens, indicative of retained allergen-specific T cell response. Mice immunisation with the hypoallergens induced IL-4, IL-5, IL-13 and IFN-γ production after antigen-specific in vitro re-stimulation of splenocytes. Moreover, murine IgG antibodies that inhibited specific IgE binding of ragweed and mugwort pollen allergic patients were detected.Accumulation of T cell epitopes and deletion of IgE reactive areas of Amb a 1 and Art v 6, modulated the immunologic properties of the allergen immuno-domains, leading to promising novel candidates for therapeutic approach.

  4. Bone marrow function. I. Peripheral T cells are responsible for the increased auto-antiidiotype response of older mice

    International Nuclear Information System (INIS)

    Kim, Y.T.; Goidl, E.A.; Samarut, C.; Weksler, M.E.; Thorbecke, G.J.; Siskind, G.W.

    1985-01-01

    After immunization with trinitrophenyl (TNP)-Ficoll, mice produced both anti-TNP antibodies and auto-anti-idiotype (auto-anti-Id) antibodies specific for the anti-TNP antibody. Older animals produced more auto-anti-Id than did young animals. When mice were exposed to a normally lethal dose of irradiation while their bone marrow (BM) was partially shielded, they survived and slowly (6 wk) regained immune function, as indicated by the number of nucleated cells in their spleen and the in vitro primary plaque-forming cell (PFC) response of their spleen cells to TNP-treated aminoethylated polyacrylamide beads. Recovery is presumably the result of repopulation of the peripheral lymphoid system by cells originating in the BM. By enzyme-linked immunosorbent assay (ELISA), and by hapten-augmentable PFC assay, the authors show that, after recovery from irradiation with their BM shielded, old animals produce low auto-anti-Id responses, like those of young animals. The transfer of splenic T cells into mice irradiated with their BM shielded provided evidence that the magnitude of the auto-anti-Id response is controlled by the peripheral T cells. Thus, mice that received splenic T cells from aged donors produced high levels of auto-anti-Id while those that received splenic T cells from young donors produce low levels of auto-anti-Id

  5. Reduced response to Epstein-Barr virus antigens by T-cells in systemic lupus erythematosus patients

    DEFF Research Database (Denmark)

    Draborg, Anette Holck; Jacobsen, Søren; Westergaard, Marie

    2014-01-01

    OBJECTIVE: Epstein-Barr virus (EBV) has for long been associated with systemic lupus erythematosus (SLE). In this study, we investigated the levels of latent and lytic antigen EBV-specific T-cells and antibodies in SLE patients. METHODS: T cells were analyzed by flow cytometry and antibodies were...... analyzed by enzyme-linked immunosorbent assay. RESULTS: SLE patients showed a significantly reduced number of activated (CD69) T-cells upon ex vivo stimulation with EBV nuclear antigen (EBNA) 1 or EBV early antigen diffuse (EBV-EA/D) in whole blood samples compared with healthy controls. Also, a reduced...... number of T-cells from SLE patients were found to produce interferon-γ upon stimulation with these antigens. Importantly, responses to a superantigen were normal in SLE patients. Compared with healthy controls, SLE patients had fewer EBV-specific T-cells but higher titres of antibodies against EBV...

  6. Unconventional Pro-inflammatory CD4+ T Cell Response in B Cell-Deficient Mice Infected with Trypanosoma cruzi

    Directory of Open Access Journals (Sweden)

    Melisa Gorosito Serrán

    2017-11-01

    Full Text Available Chagas disease, caused by the parasite Trypanosoma cruzi, is endemic in Latin America but has become a global public health concern by migration of infected people. It has been reported that parasite persistence as well as the intensity of the inflammatory immune response are determinants of the clinical manifestations of the disease. Even though inflammation is indispensable for host defense, when deregulated, it can contribute to tissue injury and organ dysfunction. Here, we report the importance of B cells in conditioning T cell response in T. cruzi infection. Mice deficient in mature B cells (muMT mice infected with T. cruzi exhibited an increase in plasma TNF concentration, TNF-producing CD4+ T cells, and mortality. The increase in TNF-producing CD4+ T cells was accompanied by a reduction in IFNγ+CD4+ T cells and a decrease of the frequency of regulatory Foxp3+, IL-10+, and IL17+CD4+ T cells populations. The CD4+ T cell population activated by T. cruzi infection, in absence of mature B cells, had a high frequency of Ly6C+ cells and showed a lower expression of inhibitory molecules such as CTLA-4, PD-1, and LAG3. CD4+ T cells from infected muMT mice presented a high frequency of CD62LhiCD44− cells, which is commonly associated with a naïve phenotype. Through transfer experiments we demonstrated that CD4+ T cells from infected muMT mice were able to condition the CD4+ T cells response from infected wild-type mice. Interestingly, using Blimp-flox/flox-CD23icre mice we observed that in absence of plasmablast/plasma cell T. cruzi-infected mice exhibited a higher number of TNF-producing CD4+ T cells. Our results showed that the absence of B cells during T. cruzi infection affected the T cell response at different levels and generated a favorable scenario for unconventional activation of CD4+ T cell leading to an uncontrolled effector response and inflammation. The product of B cell differentiation, the plasmablast/plasma cells, could be able

  7. Calcium channel antagonist (nifedipine) attenuates Plasmodium berghei-specific T cell immune responses in Balb/C mice.

    Science.gov (United States)

    Moshal, Karni S; Adhikari, Jawahar S; Bist, Kamana; Nair, Unnikrishnan; Dwarakanath, B S; Katyal, Anju; Chandra, Ramesh

    2007-08-01

    Nifedipine and verapamil (Martin et al. Science 1987;235:899-901) are a class of calcium channel blockers involved in the reversal of chloroquine (CQ) drug resistance in CQ-sensitive Plasmodium spp. Nifedipine alters calcium-dependent functions of macrophages and neutrophils during Plasmodium berghei malaria. However, knowledge of nifedipine-induced immunomodulation of T cell functions during P. berghei malaria is still limited. We investigated the effect of nifedipine on the immune status of splenic T cells during P. berghei malaria. The intracellular calcium levels were determined in the FURA-2A/M loaded T cells by spectrofluorometry. Splenic T cell proliferation, phosphatidylserine (PS) externalization, Fas expression and Bcl2/Bax expression were determined by flow cytometry. We report a significant increase in mean percent parasitemia in nifedipine-treated and P. berghei-infected mice. Although nifedipine treatment alone did not affect the resting state free calcium levels in splenic T cells, the rise in intracellular calcium levels of T cells following P. berghei infection was significantly less in nifedipine-treated mice compared to untreated groups at various parasitemia levels. Antigen-specific splenic T cell proliferation and apoptosis was ablated in nifedipine-treated and untreated groups at various parasitemia levels. The study unequivocally reflects the suppression of P. berghei-specific T cell immune responses by nifedipine.

  8. Passive Immunotherapy for Retroviral Disease: Influence of Major Histocompatibility Complex Type and T-Cell Responsiveness

    Science.gov (United States)

    Hasenkrug, Kim J.; Brooks, Diane M.; Chesebro, Bruce

    1995-11-01

    Administration of virus-specific antibodies is known to be an effective early treatment for some viral infections. Such immunotherapy probably acts by antibody-mediated neutralization of viral infectivity and is often thought to function independently of T-cell-mediated immune responses. In the present experiments, we studied passive antibody therapy using Friend murine leukemia virus complex as a model for an immunosuppressive retroviral disease in adult mice. The results showed that antibody therapy could induce recovery from a well-established retroviral infection. However, the success of therapy was dependent on the presence of both CD4^+ and CD8^+ T lymphocytes. Thus, cell-mediated responses were required for recovery from infection even in the presence of therapeutic levels of antibody. The major histocompatibility type of the mice was also an important factor determining the relative success of antibody therapy in this system, but it was less critical for low-dose than for high-dose infections. Our results imply that limited T-cell responsiveness as dictated by major histocompatibility genes and/or stage of disease may have contributed to previous immunotherapy failures in AIDS patients. Possible strategies to improve the efficacy of future therapies are discussed.

  9. Leukemia-associated activating mutation of Flt3 expands dendritic cells and alters T cell responses.

    Science.gov (United States)

    Lau, Colleen M; Nish, Simone A; Yogev, Nir; Waisman, Ari; Reiner, Steven L; Reizis, Boris

    2016-03-07

    A common genetic alteration in acute myeloid leukemia is the internal tandem duplication (ITD) in FLT3, the receptor for cytokine FLT3 ligand (FLT3L). Constitutively active FLT3-ITD promotes the expansion of transformed progenitors, but also has pleiotropic effects on hematopoiesis. We analyzed the effect of FLT3-ITD on dendritic cells (DCs), which express FLT3 and can be expanded by FLT3L administration. Pre-leukemic mice with the Flt3(ITD) knock-in allele manifested an expansion of classical DCs (cDCs) and plasmacytoid DCs. The expansion originated in DC progenitors, was cell intrinsic, and was further enhanced in Flt3(ITD/ITD) mice. The mutation caused the down-regulation of Flt3 on the surface of DCs and reduced their responsiveness to Flt3L. Both canonical Batf3-dependent CD8(+) cDCs and noncanonical CD8(+) cDCs were expanded and showed specific alterations in their expression profiles. Flt3(ITD) mice showed enhanced capacity to support T cell proliferation, including a cell-extrinsic expansion of regulatory T (T reg) cells. Accordingly, these mice restricted alloreactive T cell responses during graft-versus-host reaction, but failed to control autoimmunity without T reg cells. Thus, the FLT3-ITD mutation directly affects DC development, indirectly modulating T cell homeostasis and supporting T reg cell expansion. We hypothesize that this effect of FLT3-ITD might subvert immunosurveillance and promote leukemogenesis in a cell-extrinsic manner. © 2016 Lau et al.

  10. An Analysis of Natural T Cell Responses to Predicted Tumor Neoepitopes

    Directory of Open Access Journals (Sweden)

    Anne-Mette Bjerregaard

    2017-11-01

    Full Text Available Personalization of cancer immunotherapies such as therapeutic vaccines and adoptive T-cell therapy may benefit from efficient identification and targeting of patient-specific neoepitopes. However, current neoepitope prediction methods based on sequencing and predictions of epitope processing and presentation result in a low rate of validation, suggesting that the determinants of peptide immunogenicity are not well understood. We gathered published data on human neopeptides originating from single amino acid substitutions for which T cell reactivity had been experimentally tested, including both immunogenic and non-immunogenic neopeptides. Out of 1,948 neopeptide-HLA (human leukocyte antigen combinations from 13 publications, 53 were reported to elicit a T cell response. From these data, we found an enrichment for responses among peptides of length 9. Even though the peptides had been pre-selected based on presumed likelihood of being immunogenic, we found using NetMHCpan-4.0 that immunogenic neopeptides were predicted to bind significantly more strongly to HLA compared to non-immunogenic peptides. Investigation of the HLA binding strength of the immunogenic peptides revealed that the vast majority (96% shared very strong predicted binding to HLA and that the binding strength was comparable to that observed for pathogen-derived epitopes. Finally, we found that neopeptide dissimilarity to self is a predictor of immunogenicity in situations where neo- and normal peptides share comparable predicted binding strength. In conclusion, these results suggest new strategies for prioritization of mutated peptides, but new data will be needed to confirm their value.

  11. Surfactant Protein-A inhibits Aspergillus fumigatus-induced allergic T-cell responses

    Directory of Open Access Journals (Sweden)

    Russo Scott J

    2005-08-01

    Full Text Available Abstract Background The pulmonary surfactant protein (SP-A has potent immunomodulatory activities but its role and regulation during allergic airway inflammation is unknown. Methods We studied changes in SP-A expression in the bronchoalveolar lavage (BAL using a murine model of single Aspergillus fumigatus (Af challenge of sensitized animals. Results SP-A protein levels in the BAL fluid showed a rapid, transient decline that reached the lowest values (25% of controls 12 h after intranasal Af provocation of sensitized mice. Decrease of SP-A was associated with influx of inflammatory cells and increase of IL-4 and IL-5 mRNA and protein levels. Since levels of SP-A showed a significant negative correlation with these BAL cytokines (but not with IFN-γ, we hypothesized that SP-A exerts an inhibitory effect on Th2-type immune responses. To study this hypothesis, we used an in vitro Af-rechallenge model. Af-induced lymphocyte proliferation of cells isolated from sensitized mice was inhibited in a dose-dependent manner by addition of purified human SP-A (0.1–10 μg/ml. Flow cytometric studies on Af-stimulated lymphocytes indicated that the numbers of CD4+ (but not CD8+ T cells were significantly increased in the parental population and decreased in the third and fourth generation in the presence of SP-A. Further, addition of SP-A to the tissue culture inhibited Af-induced IL-4 and IL-5 production suggesting that SP-A directly suppressed allergen-stimulated CD4+ T cell function. Conclusion We speculate that a transient lack of this lung collectin following allergen exposure of the airways may significantly contribute to the development of a T-cell dependent allergic immune response.

  12. Experimental autoimmune encephalomyelitis in the Wistar rat: dependence of MBP-specific T cell responsiveness on B7 costimulation.

    Science.gov (United States)

    Zhou, Jing; Zhang, Jia-Sheng; Ma, Bao-Li; Mamula, Mark J

    2002-05-01

    Experimental autoimmune encephalomyelitis (EAE) is an animal model of human multiple sclerosis that requires the activation of autoreactive T cells for the expression of pathology. EAE has been most frequently studied in the Lewis rat model as well as in several murine models of EAE including the PLJ and B10PL strains. In the present study we describe a novel model of EAE induced in the Wistar rat strain by immunization with guinea pig spinal cord antigens and pertussis toxin (PT). T cell responses were induced to myelin basic protein. Autoreactive T cells could be totally blocked by the in vitro treatment with CTLA4Ig, a protein that blocks the costimulation of autoreactive T cells. The addition of IL-2 could reverse the inhibition seen in vitro with CTLA4Ig. The effects of inhibition of B7 costimulation were also examined by an analysis of cytokine responses and IL-2 receptor on T cells. CTLA4Ig treatment in vitro reduced the expression of IL-2 receptor on T cells, enhanced T cell apoptosis and decreased the synthesis of IL-2, IFN-gamma and TNF-alpha. CTLA4Ig treatment had no effect on IL-10 synthesis by T cells, a cytokine implicated in the functions of regulatory T cell subsets. Overall, our studies support the rationale of B7 blocking therapies as a potential treatment for models of multiple sclerosis. The induction of EAE in the Wistar rat provides yet another novel model in which to examine the regulation of T cell autoimmunity.

  13. Loss of immunization-induced epitope-specific CD4 T-cell response following anaplasma marginale infection requires presence of the T-cell epitope on the pathogen and is not associated with an increase in lymphocytes

    Science.gov (United States)

    We have shown that in cattle previously immunized with outer membrane proteins, infection with Anaplasma marginale induces a functionally exhausted CD4 T-cell response to the A. marginale immunogen. Furthermore, T-cell responses following infection in nonimmunized cattle had a delayed onset and were...

  14. Differential proliferative responses in subsets of human CD28+ cells delineated by BB27 mAb.

    Science.gov (United States)

    Gouttefangeas, C; Jacquot, S; Meffre, E; Schmid, M; Boumsell, L; Bensussan, A

    1994-03-01

    We report the identification of a novel 140 kDa disulfide-linked dimer expressed by a subset of peripheral blood T lymphocytes. This molecule, which is recognized by mAb BB27, is also detected on cells of the myelomonocytic lineage. In the T cell lineage, its expression is positively modulated after lymphocyte activation. A series of double-labeling experiments revealed that BB27 mAb identifies new CD4 and CD8 cell subsets different from those defined by CD45RA, CD45RO, CD26, CD29, CD31, and CD38. Finally, BB27 mAb also subdivides the CD28 subset. Of the utmost interest is the finding that a proliferative response to CD28 mAb and phorbol myristate acetate stimulation is exclusively obtained in the CD28+BB27+ cell subset, whereas the CD28+BB27- subset fails to proliferate.

  15. HIV-1 transgenic rat CD4+ T cells develop decreased CD28 responsiveness and suboptimal Lck tyrosine dephosphorylation following activation

    International Nuclear Information System (INIS)

    Yadav, Anjana; Pati, Shibani; Nyugen, Anhthu; Barabitskaja, Oxana; Mondal, Prosanta; Anderson, Michael; Gallo, Robert C.; Huso, David L.; Reid, William

    2006-01-01

    Impaired CD4+ T cell responses, resulting in dysregulated T-helper 1 (Th1) effector and memory responses, are a common result of HIV-1 infection. These defects are often preceded by decreased expression and function of the α/β T cell receptor (TCR)-CD3 complex and of co-stimulatory molecules including CD28, resulting in altered T cell proliferation, cytokine secretion and cell survival. We have previously shown that HIV Tg rats have defective development of T cell effector function and generation of specific effector/memory T cell subsets. Here we identify abnormalities in activated HIV-1 Tg rat CD4+ T cells that include decreased pY505 dephosphorylation of Lck (required for Lck activation), decreased CD28 function, reduced expression of the anti-apoptotic molecule Bcl-xL, decreased secretion of the mitogenic lympokine interleukin-2 (IL-2) and increased activation induced apoptosis. These events likely lead to defects in antigen-specific signaling and may help explain the disruption of Th1 responses and the generation of specific effector/memory subsets in transgenic CD4+ T cells

  16. MHC-based detection of antigen-specific CD8(+) T cell responses

    DEFF Research Database (Denmark)

    Hadrup, Sine Reker; Schumacher, Nana Maria Pii

    2010-01-01

    epitopes in limited biological material. These technologies are based on the joint binding of differentially labelled MHC multimers on the T cell surface, thereby providing each antigen-specific T cell population with a unique multicolour code. This strategy of 'combinatorial encoding' enables detection...... of many (at least 25) different T cell populations per sample and should be of broad value for both T cell epitope identification and immunomonitoring...

  17. Systemic T cell response to Toxoplasma gondii antigen in patients with ocular toxoplasmosis.

    Science.gov (United States)

    Fatoohi, Fatih; Cozon, Grégoire Jacques Noël; Wallon, Martine; Kodjikian, Laurent; Peyron, François

    2006-01-01

    Analysis of systemic cellular response to Toxoplasma antigen in patients with ocular toxoplasmosis. Activated (CD25(+)) T cells were detected by flow cytometry after a 7-day culture of whole blood from patients with ocular (n = 16) or asymptomatic (n = 14) toxoplasmosis, and controls (n = 10), in the presence of soluble Toxoplasma antigen (ST-Ag). Interferon (IFN)-gamma, interleukin (IL) 4, and IL-10 were measured in culture supernatants by enzyme-linked immunosorbent assay. Higher percentages of CD25(+) T cells were detected in ST-Ag-activated cultures from Toxoplasma-infected patients, with or without ocular lesions (37.0 +/- 19.1% or 41.1 +/- 19.3%, respectively) than from controls (3.2 +/- 1.2%) (P 0.4) or among congenital, acquired, and undetermined ocular toxoplasmosis (P > 0.2). Higher levels of IFN-gamma were detected in ST-Ag-stimulated blood cultures from infected patients than in those from controls (P 0.05). IL-10 was detected only in activated culture supernatants from three patients with ocular toxoplasmosis and two patients with asymptomatic toxoplasmosis. IL-4 was never produced in ST-Ag-activated cultures. Systemic cellular response to ST-Ag does not differ between the patients with ocular and asymptomatic toxoplasmosis with regard to activation markers and type 1 cytokine production.

  18. T-Cell Mediated Immune Responses Induced in ret Transgenic Mouse Model of Malignant Melanoma

    International Nuclear Information System (INIS)

    Abschuetz, Oliver; Osen, Wolfram; Frank, Kathrin; Kato, Masashi; Schadendorf, Dirk; Umansky, Viktor

    2012-01-01

    Poor response of human malignant melanoma to currently available treatments requires a development of innovative therapeutic strategies. Their evaluation should be based on animal models that resemble human melanoma with respect to genetics, histopathology and clinical features. Here we used a transgenic mouse model of spontaneous skin melanoma, in which the ret transgene is expressed in melanocytes under the control of metallothionein-I promoter. After a short latency, around 25% mice develop macroscopic skin melanoma metastasizing to lymph nodes, bone marrow, lungs and brain, whereas other transgenic mice showed only metastatic lesions without visible skin tumors. We found that tumor lesions expressed melanoma associated antigens (MAA) tyrosinase, tyrosinase related protein (TRP)-1, TRP-2 and gp100, which could be applied as targets for the immunotherapy. Upon peptide vaccination, ret transgenic mice without macroscopic melanomas were able to generate T cell responses not only against a strong model antigen ovalbumin but also against typical MAA TRP-2. Although mice bearing macroscopic primary tumors could also display an antigen-specific T cell reactivity, it was significantly down-regulated as compared to tumor-free transgenic mice or non-transgenic littermates. We suggest that ret transgenic mice could be used as a pre-clinical model for the evaluation of novel strategies of melanoma immunotherapy

  19. T-Cell Mediated Immune Responses Induced in ret Transgenic Mouse Model of Malignant Melanoma

    Directory of Open Access Journals (Sweden)

    Dirk Schadendorf

    2012-04-01

    Full Text Available Poor response of human malignant melanoma to currently available treatments requires a development of innovative therapeutic strategies. Their evaluation should be based on animal models that resemble human melanoma with respect to genetics, histopathology and clinical features. Here we used a transgenic mouse model of spontaneous skin melanoma, in which the ret transgene is expressed in melanocytes under the control of metallothionein-I promoter. After a short latency, around 25% mice develop macroscopic skin melanoma metastasizing to lymph nodes, bone marrow, lungs and brain, whereas other transgenic mice showed only metastatic lesions without visible skin tumors. We found that tumor lesions expressed melanoma associated antigens (MAA tyrosinase, tyrosinase related protein (TRP-1, TRP-2 and gp100, which could be applied as targets for the immunotherapy. Upon peptide vaccination, ret transgenic mice without macroscopic melanomas were able to generate T cell responses not only against a strong model antigen ovalbumin but also against typical MAA TRP-2. Although mice bearing macroscopic primary tumors could also display an antigen-specific T cell reactivity, it was significantly down-regulated as compared to tumor-free transgenic mice or non-transgenic littermates. We suggest that ret transgenic mice could be used as a pre-clinical model for the evaluation of novel strategies of melanoma immunotherapy.

  20. Compensatory T cell responses in IRG-deficient mice prevent sustained Chlamydia trachomatis infections.

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    Jörn Coers

    2011-06-01

    Full Text Available The obligate intracellular pathogen Chlamydia trachomatis is the most common cause of bacterial sexually transmitted diseases in the United States. In women C. trachomatis can establish persistent genital infections that lead to pelvic inflammatory disease and sterility. In contrast to natural infections in humans, experimentally induced infections with C. trachomatis in mice are rapidly cleared. The cytokine interferon-γ (IFNγ plays a critical role in the clearance of C. trachomatis infections in mice. Because IFNγ induces an antimicrobial defense system in mice but not in humans that is composed of a large family of Immunity Related GTPases (IRGs, we questioned whether mice deficient in IRG immunity would develop persistent infections with C. trachomatis as observed in human patients. We found that IRG-deficient Irgm1/m3((-/- mice transiently develop high bacterial burden post intrauterine infection, but subsequently clear the infection more efficiently than wildtype mice. We show that the delayed but highly effective clearance of intrauterine C. trachomatis infections in Irgm1/m3((-/- mice is dependent on an exacerbated CD4(+ T cell response. These findings indicate that the absence of the predominant murine innate effector mechanism restricting C. trachomatis growth inside epithelial cells results in a compensatory adaptive immune response, which is at least in part driven by CD4(+ T cells and prevents the establishment of a persistent infection in mice.

  1. Wildtype p53-specific Antibody and T-Cell Responses in Cancer Patients

    DEFF Research Database (Denmark)

    Pedersen, Anders Elm; Stryhn, Anette; Justesen, Sune

    2011-01-01

    Mutation in the p53 gene based on single amino acid substitutions is a frequent event in human cancer. Accumulated mutant p53 protein is released to antigen presenting cells of the immune system and anti-p53 immune responses even against wt p53 is induced and observed in a number of human cancer...... patients. Detection of antibodies against wt p53 protein has been used as a diagnostic and prognostic marker and discovery of new T-cell epitopes has enabled design of cancer vaccination protocols with promising results. Here, we identified wt p53-specific antibodies in various cancer patients......(264-272) in breast cancer patients and against HLA-A*01:01 binding peptide wt p53(226-234) and HLA-B*07:02 binding peptide wt p53(74-82) in renal cell cancer and breast cancer patients, respectively. Finally, we analyzed antibody and T-cell responses against wt p53 15-mer peptides in patients with metastatic renal...

  2. T-Cell Mediated Immune Responses Induced in ret Transgenic Mouse Model of Malignant Melanoma

    Energy Technology Data Exchange (ETDEWEB)

    Abschuetz, Oliver [Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg and Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, Ruprecht-Karl University of Heidelberg, Mannheim , Heidelberg 69120 (Germany); Osen, Wolfram [Division of Translational Immunology, German Cancer Center, Heidelberg 69120 (Germany); Frank, Kathrin [Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg and Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, Ruprecht-Karl University of Heidelberg, Mannheim , Heidelberg 69120 (Germany); Kato, Masashi [Unit of Environmental Health Sciences, Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Aichi 487-8501 (Japan); Schadendorf, Dirk [Department of Dermatology, University Hospital Essen, Essen 45122 (Germany); Umansky, Viktor, E-mail: v.umansky@dkfz.de [Skin Cancer Unit, German Cancer Research Center (DKFZ), Heidelberg and Department of Dermatology, Venereology and Allergology, University Medical Center Mannheim, Ruprecht-Karl University of Heidelberg, Mannheim , Heidelberg 69120 (Germany)

    2012-04-26

    Poor response of human malignant melanoma to currently available treatments requires a development of innovative therapeutic strategies. Their evaluation should be based on animal models that resemble human melanoma with respect to genetics, histopathology and clinical features. Here we used a transgenic mouse model of spontaneous skin melanoma, in which the ret transgene is expressed in melanocytes under the control of metallothionein-I promoter. After a short latency, around 25% mice develop macroscopic skin melanoma metastasizing to lymph nodes, bone marrow, lungs and brain, whereas other transgenic mice showed only metastatic lesions without visible skin tumors. We found that tumor lesions expressed melanoma associated antigens (MAA) tyrosinase, tyrosinase related protein (TRP)-1, TRP-2 and gp100, which could be applied as targets for the immunotherapy. Upon peptide vaccination, ret transgenic mice without macroscopic melanomas were able to generate T cell responses not only against a strong model antigen ovalbumin but also against typical MAA TRP-2. Although mice bearing macroscopic primary tumors could also display an antigen-specific T cell reactivity, it was significantly down-regulated as compared to tumor-free transgenic mice or non-transgenic littermates. We suggest that ret transgenic mice could be used as a pre-clinical model for the evaluation of novel strategies of melanoma immunotherapy.

  3. Intestinal T-cell responses in celiac disease - impact of celiac disease associated bacteria.

    Directory of Open Access Journals (Sweden)

    Veronika Sjöberg

    Full Text Available A hallmark of active celiac disease (CD, an inflammatory small-bowel enteropathy caused by permanent intolerance to gluten, is cytokine production by intestinal T lymphocytes. Prerequisites for contracting CD are that the individual carries the MHC class II alleles HLA-DQ2 and/or HLA-DQ8 and is exposed to gluten in the diet. Dysbiosis in the resident microbiota has been suggested to be another risk factor for CD. In fact, rod shaped bacteria adhering to the small intestinal mucosa were frequently seen in patients with CD during the "Swedish CD epidemic" and bacterial candidates could later be isolated from patients born during the epidemic suggesting long-lasting changes in the gut microbiota. Interleukin-17A (IL-17A plays a role in both inflammation and anti-bacterial responses. In active CD IL-17A was produced by both CD8(+ T cells (Tc17 and CD4(+ T cells (Th17, with intraepithelial Tc17 cells being the dominant producers. Gluten peptides as well as CD associated bacteria induced IL-17A responses in ex vivo challenged biopsies from patients with inactive CD. The IL-17A response was suppressed in patients born during the epidemic when a mixture of CD associated bacteria was added to gluten, while the reverse was the case in patients born after the epidemic. Under these conditions Th17 cells were the dominant producers. Thus Tc17 and Th17 responses to gluten and bacteria seem to pave the way for the chronic disease with interferon-γ-production by intraepithelial Tc1 cells and lamina propria Th1 cells. The CD associated bacteria and the dysbiosis they might cause in the resident microbiota may be a risk factor for CD either by directly influencing the immune responses in the mucosa or by enhancing inflammatory responses to gluten.

  4. Follicular helper T cells mediate IgE antibody response to airborne allergens.

    Science.gov (United States)

    Kobayashi, Takao; Iijima, Koji; Dent, Alexander L; Kita, Hirohito

    2017-01-01

    T H 2 cells have long been believed to play a pivotal role in allergic immune responses, including IgE antibody production and type 2 cytokine-mediated inflammation and pathology. A new T-cell subset, follicular helper T (T FH ) cells, is specialized in supporting B-cell maturation and antibody production. We sought to investigate the roles of T FH cells in allergic immune responses. Naive mice were exposed to cytokines or natural allergens through the airways. Development of allergic immune responses was analyzed by collecting draining lymph nodes and sera and by challenging the animals. Cytokine reporter mice and gene-deficient mice were used to dissect the immunologic mechanisms. We observed the development of IL-4-producing T FH cells and T H 2 cells in draining lymph nodes after airway exposure to IL-1 family cytokines or natural allergens. T FH and T H 2 cells demonstrated unique phenotypes, tissue localization, and cytokine responses. T FH cells supported the sustained production of IgE antibody in vivo in the absence of other T-cell subsets or even when T H 2 cell functions were severely compromised. Conversely, conditional deficiency of the master regulator Bcl6 in CD4 + T cells resulted in a marked reduction in T FH cell numbers and IgE antibody levels, but type 2 cytokine responses and eosinophilic inflammation in the airways remained unaffected. T FH cells play critical roles in the regulation of IgE antibody production. Allergic immune responses to airborne allergens likely involve 2 distinct subsets of IL-4-producing CD4 + T cells, namely T FH and Th2 cells. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  5. IL-2 and IL-15 regulate CD8+ memory T-cell differentiation but are dispensable for protective recall responses.

    Science.gov (United States)

    Mathieu, Cédric; Beltra, Jean-Christophe; Charpentier, Tania; Bourbonnais, Sara; Di Santo, James P; Lamarre, Alain; Decaluwe, Hélène

    2015-12-01

    The ability to mount effective secondary responses is a cardinal feature of memory CD8(+) T cells. An understanding of the factors that regulate the generation and recall capacities of memory T cells remains to be ascertained. Several cues indicate that two highly related cytokines, IL-2 and IL-15, share redundant functions in this process. To establish their combined roles in memory CD8(+) T-cell development, maintenance, and secondary responses, we compared the outcome of adoptively transferred IL2Rβ(+/-) or IL2Rβ(-/-) CD8(+) T cells after an acute viral infection in mice. Our results demonstrate that both IL-2 and IL-15 signals condition the differentiation of primary and secondary short-lived effector cells by altering the transcriptional network governing lineage choices. These two cytokines also regulate the homeostasis of the memory T-cell pool, with effector memory CD8(+) T cells being the most sensitive to these two interleukins. Noticeably, the inability to respond to both cytokines limits the proliferation and survival of primary and secondary effectors cells, whereas it does not preclude potent cytotoxic functions and viral control either initially or upon rechallenge. Globally, these results indicate that lack of IL-2 and IL-15 signaling modulates the CD8(+) T-cell differentiation program but does not impede adequate effector functions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Rapid selection of escape mutants by the first CD8 T cell responses in acute HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Korber, Bette Tina Marie [Los Alamos National Laboratory

    2008-01-01

    The recent failure of a vaccine that primes T cell responses to control primary HIV-1 infection has raised doubts about the role of CD8+ T cells in early HIV-1 infection. We studied four patients who were identified shortly after HIV-1 infection and before seroconversion. In each patient there was very rapid selection of multiple HIV-1 escape mutants in the transmitted virus by CD8 T cells, including examples of complete fixation of non-synonymous substitutions within 2 weeks. Sequencing by single genome amplification suggested that the high rate of virus replication in acute infection gave a selective advantage to virus molecules that contained simultaneous and gained sequential T cell escape mutations. These observations show that whilst early HIV-1 specific CD8 T cells can act against virus, rapid escape means that these T cell responses are unlikely to benefit the patient and may in part explain why current HIV-1 T cell vaccines may not be protective.

  7. Antigen-specific B cells reactivate an effective cytotoxic T cell response against phagocytosed Salmonella through cross-presentation.

    Science.gov (United States)

    de Wit, Jelle; Souwer, Yuri; Jorritsma, Tineke; Klaasse Bos, Hanny; ten Brinke, Anja; Neefjes, Jacques; van Ham, S Marieke

    2010-09-27

    The eradication of facultative intracellular bacterial pathogens, like Salmonella typhi, requires the concerted action of both the humoral immune response and the cytotoxic CD8(+) T cell response. Dendritic cells (DCs) are considered to orchestrate the cytotoxic CD8(+) T cell response via cross-presentation of bacterial antigens onto MHC class I molecules. Cross-presentation of Salmonella by DCs however, is accompanied by the induction of apoptosis in the DCs. Besides antibody production, B cells are required to clear Salmonella infection for other unknown reasons. Here we show that Salmonella-specific B cells that phagocytose Salmonella upon BCR-ligation reactivate human memory CD8(+) T cells via cross-presentation yielding a Salmonella-specific cytotoxic T cell response. The reactivation of CD8(+) T cells is dependent on CD4(+) T cell help. Unlike the DCs, B cell-mediated cross-presentation of Salmonella does not coincide with apoptosis. B cells form a new player in the activation of the cytotoxic effector arm of the immune response and the generation of effective adaptive immunity in Salmonella infection.

  8. Oral vaccination with lipid-formulated BCG induces a long-lived, multifunctional CD4(+ T cell memory immune response.

    Directory of Open Access Journals (Sweden)

    Lindsay R Ancelet

    Full Text Available Oral delivery of BCG in a lipid formulation (Liporale™-BCG targets delivery of viable bacilli to the mesenteric lymph nodes and confers protection against an aerosol Mycobacterium tuberculosis challenge. The magnitude, quality and duration of the effector and memory immune response induced by Liporale™-BCG vaccination is unknown. Therefore, we compared the effector and memory CD4(+ T cell response in the spleen and lungs of mice vaccinated with Liporale™-BCG to the response induced by subcutaneous BCG vaccination. Liporale™-BCG vaccination induced a long-lived CD4(+ T cell response, evident by the detection of effector CD4(+ T cells in the lungs and a significant increase in the number of Ag85B tetramer-specific CD4(+ T cells in the spleen up to 30 weeks post vaccination. Moreover, following polyclonal stimulation, Liporale™-BCG vaccination, but not s.c. BCG vaccination, induced a significant increase in both the percentage of CD4(+ T cells in the lungs capable of producing IFNγ and the number of multifunctional CD4(+ T cells in the lungs at 30 weeks post vaccination. These results demonstrate that orally delivered Liporale™-BCG vaccine induces a long-lived multifunctional immune response, and could therefore represent a practical and effective means of delivering novel BCG-based TB vaccines.

  9. IL-27 affects helper T cell responses via regulation of PGE2 production by macrophages.

    Science.gov (United States)

    Sato, Yayoi; Hara, Hiromitsu; Okuno, Toshiaki; Ozaki, Naoko; Suzuki, Shinobu; Yokomizo, Takehiko; Kaisho, Tsuneyasu; Yoshida, Hiroki

    2014-08-22

    IL-27 is a heterodimeric cytokine that regulates both innate and adaptive immunity. The immunosuppressive effect of IL-27 largely depends on induction of IL-10-producing Tr1 cells. To date, however, effects of IL-27 on regulation of immune responses via mediators other than cytokines remain poorly understood. To address this issue, we examined immunoregulatory effects of conditional medium of bone marrow-derived macrophages (BMDMs) from WSX-1 (IL-27Rα)-deficient mice and found enhanced IFN-γ and IL-17A secretion by CD4(+) T cells as compared with that of control BMDMs. We then found that PGE2 production and COX-2 expression by BMDMs from WSX-1-deficient mice was increased compared to control macrophages in response to LPS. The enhanced production of IFN-γ and IL-17A was abolished by EP2 and EP4 antagonists, demonstrating PGE2 was responsible for enhanced cytokine production. Murine WSX-1-expressing Raw264.7 cells (mWSX-1-Raw264.7) showed phosphorylation of both STAT1 and STAT3 in response to IL-27 and produced less amounts of PGE2 and COX-2 compared to parental RAW264.7 cells. STAT1 knockdown in parental RAW264.7 cells and STAT1-deficiency in BMDMs showed higher COX-2 expression than their respective control cells. Collectively, our result indicated that IL-27/WSX-1 regulated PGE2 secretion via STAT1-COX-2 pathway in macrophages and affected helper T cell response in a PGE2-mediated fashion. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Effect of anti-IgE therapy on food allergen specific T cell responses in eosinophil associated gastrointestinal disorders

    Directory of Open Access Journals (Sweden)

    Prussin Calman

    2011-04-01

    Full Text Available Abstract Background Anti-IgE therapy inhibits mast cell and basophil activation, blocks IgE binding to both FcεRI and CD23 and down regulates FcεRI expression by antigen (Ag presenting cells (APCs. In addition to its classical role in immediate hypersensitivity, IgE has been shown in vitro to facilitate Ag presentation of allergens, whereby APC bound IgE preferentially takes up allergens for subsequent processing and presentation. The purpose of this study was to determine whether anti-IgE therapy, by blocking facilitated Ag presentation in vivo, attenuates allergen specific Th2 cell responses. Methods To test this hypothesis, food allergen specific T cell responses were examined during a 16-week clinical trial of omalizumab in nine subjects with eosinophilic gastroenteritis and food sensitization. Allergen specific T cell responses were measured using carboxyfluorescein succinimidyl ester dye dilution coupled with intracellular cytokine staining and polychromatic flow cytometry. Four independent indices of allergen specific T cell response (proliferation, Ag dose response, precursor frequency, and the ratio of Th2:Th1 cytokine expression were determined. Results Eight of the 9 subjects had measurable food allergen specific responses, with a median proliferation index of 112-fold. Allergen specific T cell proliferation was limited to CD4 T cells, whereas CD8 T cell did not proliferate. Food allergen specific responses were Th2 skewed relative to tetanus specific responses in the same subjects. In contradistinction to the original hypothesis, anti-IgE treatment did not diminish any of the four measured indices of allergen specific T cell response. Conclusions In sum, using multiple indices of T cell function, this study failed to demonstrate that anti-IgE therapy broadly or potently inhibits allergen specific T cell responses. As such, these data do not support a major role for IgE facilitated Ag presentation augmenting allergen specific T cell

  11. Fecal bacteria from treatment-naive Crohn's disease patients can skew helper T cell responses.

    Science.gov (United States)

    Ma, Fei; Zhang, Yi; Xing, Junjie; Song, Xiaoling; Huang, Ling; Weng, Hao; Wu, Xiangsong; Walker, Emma; Wang, Zhongchuan

    2017-12-01

    Many studies have demonstrated that the inflamed mucosa of Crohn's disease (CD) patients presented a disturbed gut commensal community, and the shift in microbial composition and species variety is associated with disease severity. To establish a link between changes in the intestinal bacterial composition and the alteration of inflammation, we obtained fecal bacteria from CD patients and non-CD controls. The bacteria were then used to stimulate the peripheral blood mononuclear cells (PBMCs) from one non-CD individual. We found that the frequency of IFN-γ- and IL-17-expressing CD4 T cells was significantly higher after stimulation with CD bacteria than with non-CD bacteria, while the frequency of IL-4- and IL-10-expressing CD4 T cells was significantly decreased after stimulation with CD bacteria. A similar trend was observed in the level of cytokine expression and transcription expression. However, this difference was not clear-cut, as overlapping regions were observed between the two groups. With longer stimulation using CD bacteria, the skewing toward Th1/Th17 responses were further increased. This increase depended on the presence of monocytes/macrophages. Interestingly, we also found that B cells presented an inhibitory effect in CD bacteria-mediated skewing toward Th1/Th17 cells and promoted IL-10 secretion in CD bacteria-stimulated PBMCs. Together, our results demonstrated that CD bacteria could promote Th1/Th17 inflammation in a host factor-independent fashion. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Impaired antibody response causes persistence of prototypic T cell-contained virus.

    Directory of Open Access Journals (Sweden)

    Andreas Bergthaler

    2009-04-01

    Full Text Available CD8 T cells are recognized key players in control of persistent virus infections, but increasing evidence suggests that assistance from other immune mediators is also needed. Here, we investigated whether specific antibody responses contribute to control of lymphocytic choriomeningitis virus (LCMV, a prototypic mouse model of systemic persistent infection. Mice expressing transgenic B cell receptors of LCMV-unrelated specificity, and mice unable to produce soluble immunoglobulin M (IgM exhibited protracted viremia or failed to resolve LCMV. Virus control depended on immunoglobulin class switch, but neither on complement cascades nor on Fc receptor gamma chain or Fc gamma receptor IIB. Cessation of viremia concurred with the emergence of viral envelope-specific antibodies, rather than with neutralizing serum activity, and even early nonneutralizing IgM impeded viral persistence. This important role for virus-specific antibodies may be similarly underappreciated in other primarily T cell-controlled infections such as HIV and hepatitis C virus, and we suggest this contribution of antibodies be given consideration in future strategies for vaccination and immunotherapy.

  13. Effect of glucocorticoids on melatonin receptor expression under T-cell activated immune response

    International Nuclear Information System (INIS)

    Tauschanova, P.; Georgiev, G.; Manchev, S.; Konakchieva, R.

    2007-01-01

    The present study was aimed to explore the stress response in rats under conditions of T-cell antigen-activated immune function and to investigate the specific melatonin (MEL) receptor binding in primary and secondary immune tissue of rats employing 2-( 125 I)-iodo melatonin autoradiography and in vitro ligand binding assay. The study revealed that melatonin receptor binding was specifically expressed in discrete areas of the lymphoid sheath of the spleen and in a network of interdigitating cells of the experimental rats. Demonstration of the modulation of MEL receptor binding in the course of a primary immune response under hypercorticalemic conditions indicate that the pineal hormone might interfere in the processes of glucocorticoid-dependent immune competency. (authors)

  14. Synthetic melanin bound to subunit vaccine antigens significantly enhances CD8+ T-cell responses.

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    Antoine F Carpentier

    Full Text Available Cytotoxic T-lymphocytes (CTLs play a key role in immunity against cancer; however, the induction of CTL responses with currently available vaccines remains difficult. Because several reports have suggested that pigmentation and immunity might be functionally linked, we investigated whether melanin can act as an adjuvant in vaccines. Short synthetic peptides (8-35 amino acids long containing T-cell epitopes were mixed with a solution of L-Dopa, a precursor of melanin. The mixture was then oxidized to generate nanoparticles of melanin-bound peptides. Immunization with melanin-bound peptides efficiently triggered CTL responses in mice, even against self-antigens and at a very low dose of peptides (microgram range. Immunization against a tumor antigen inhibited the growth of established tumors in mice, an effect that was abrogated by the depletion of CD8+ lymphocytes. These results demonstrate the efficacy of melanin as a vaccine adjuvant.

  15. Environmental immunogens and T-cell-mediated responses in fibromyalgia: evidence for immune dysregulation and determinants of granuloma formation.

    Science.gov (United States)

    Shanklin, D R; Stevens, M V; Hall, M F; Smalley, D L

    2000-10-01

    Thirty-nine patients with fibromyalgia syndrome (FMS) according to American College of Rheumatology criteria were studied for cell-mediated sensitivity to environmental chemicals. Lymphocytes were tested by standard [(3)H]thymidine incorporation in vitro for T cell memory to 11 chemical substances. Concanavalin A (Con A) was used to demonstrate T cell proliferation. Controls were 25 contemporaneous healthy adults and 252 other concurrent standard controls without any aspect of FMS. Significantly higher (P P > 0.02) SI were found for cadmium and silicon. FMS patients showed sporadic responses to the specific substances tested, with no high-frequency result (>50%) and no obvious pattern. Mitogenic responses to Con A indicated some suppression of T cell functionality in FMS. Possible links between mitogenicity and immunogenic T cell proliferation, certain electrochemical specifics of granuloma formation, maintenance of connective tissue, and the fundamental nature of FMS are considered. Copyright 2000 Academic Press.

  16. Essential role for retinoic acid in the promotion of CD4+ T cell effector responses via retinoic acid receptor alpha

    Science.gov (United States)

    Hall, J.A.; Cannons, J.L.; Grainger, J.R.; Santos, L.M. Dos; Hand, T.W.; Naik, S.; Wohlfert, E.A.; Chou, D.B.; Oldenhove, G.; Robinson, M.; Grigg, M.E.; Kastenmayer, R.; Schwartzberg, P.L.; Belkaid, Y.

    2012-01-01

    SUMMARY Vitamin A and its metabolite, retinoic acid (RA), have recently been implicated in the regulation of immune homeostasis via the peripheral induction of regulatory T cells. Here we show that RA is also required to elicit proinflammatory CD4+ helper T cell responses to infection and mucosal vaccination. Retinoic acid receptor alpha (RARα) is the critical mediator of these effects. Strikingly, antagonism of RAR signaling and deficiency in RARα(Rara−/−) results in a cell autonomous CD4+ T cell activation defect. Altogether, these findings reveal a fundamental role for the RA/RARα axis in the development of both regulatory and inflammatory arms of adaptive immunity and establish nutritional status as a broad regulator of adaptive T cell responses. PMID:21419664

  17. T-cell responses to oncogenic Merkel cell polyomavirus proteins distinguish patients with Merkel cell carcinoma from healthy donors

    DEFF Research Database (Denmark)

    Lyngaa, Rikke; Pedersen, Natasja Wulff; Schrama, David

    2014-01-01

    Purpose: Merkel cell carcinoma (MCC) is a highly aggressive skin cancer with strong evidence of viral carcinogenesis. The association of MCC with the Merkel cell polyomavirus (MCPyV) may explain the explicit immunogenicity of MCC. Indeed, MCPyV-encoded proteins are likely targets for cytotoxic...... immune responses to MCC as they are both foreign to the host and necessary to maintain the oncogenic phenotype. However, to date only a single MCPyV-derived CD8 T-cell epitope has been described, thus impeding specific monitoring of T-cell responses to MCC. Method: To overcome this limitation, we scanned...... the MCPyV oncoprotein large T and small T antigens and the virus capsid protein VP1 for potential T-cell epitopes, and tested for MHC class I affinity. We confirmed the relevance of these epitopes using a high-throughput platform for T-cell enrichment and combinatorial encoding of MHC class I multimers...

  18. The ¿/d T-cell response to Plasmodium falciparum malaria in a population in which malaria is endemic

    DEFF Research Database (Denmark)

    Hviid, L; Kurtzhals, J A; Dodoo, D

    1996-01-01

    Frequencies and absolute numbers of peripheral gamma/delta T cells have been reported to increase after episodes of Plasmodium falciparum malaria in adults with limited or no previous malaria exposure. In contrast, little is known about the gamma/delta T-cell response to malaria in children from...... areas where malaria is endemic, who bear the burden of malaria-related morbidity and mortality. We investigated the gamma/delta T-cell response in 19 Ghanaian children from an area of hyperendemic, seasonal malaria transmission. The children presented with cerebral malaria (n = 7), severe malarial...... anemia (n = 5), or uncomplicated malaria (n = 7) and were monitored from admission until 4 weeks later. We found no evidence of increased frequencies of gamma/delta T cells in any of the patient groups, whereas one adult expatriate studied in Ghana and three adults admitted to the hospital in Copenhagen...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    It is generally accepted that CD8 T cells play a major role in tumor control, yet vaccination aimed at eliciting potent CD8 T cell responses are rarely efficient in clinical trials. To try and understand why this is so, we have generated potent adenoviral vectors encoding the endogenous tumor Ags...... (TA) tyrosinase-related protein-2 (TRP-2) and glycoprotein 100 (GP100) tethered to the invariant chain (Ii). Using these vectors, we sought to characterize the self-TA-specific CD8 T cell response and compare it to that induced against non-self-Ags expressed from a similar vector platform...... construct expressing a foreign (viral) TA induced efficient tumor control. Analyzing the self-TA-specific CD8 T cells, we observed that these could be activated to produce IFN-γ and TNF-α. In addition, surface expression of phenotypic markers and inhibitory receptors, as well as in vivo cytotoxicity...

  20. Primary vaccination with low dose live dengue 1 virus generates a proinflammatory, multifunctional T cell response in humans.

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    Janet C Lindow

    Full Text Available The four dengue virus serotypes (DENV-1-DENV-4 have a large impact on global health, causing 50-100 million cases of dengue fever annually. Herein, we describe the first kinetic T cell response to a low-dose DENV-1 vaccination study (10 PFU in humans. Using flow cytometry, we found that proinflammatory cytokines, IFNγ, TNFα, and IL-2, were generated by DENV-1-specific CD4(+ cells 21 days post-DENV-1 exposure, and their production continued through the latest time-point, day 42 (p<0.0001 for all cytokines. No statistically significant changes were observed at any time-points for IL-10 (p = 0.19, a regulatory cytokine, indicating that the response to DENV-1 was primarily proinflammatory in nature. We also observed little T cell cross-reactivity to the other 3 DENV serotypes. The percentage of multifunctional T cells (T cells making ≥ 2 cytokines simultaneously increased with time post-DENV-1 exposure (p<0.0001. The presence of multifunctional T cells together with neutralizing antibody data suggest that the immune response generated to the vaccine may be protective. This work provides an initial framework for defining primary T cell responses to each DENV serotype and will enhance the evaluation of a tetravalent DENV vaccine.

  1. Anergy-associated T cell antigen presentation. A mechanism of infectious tolerance in experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Mannie, M D; Rendall, S K; Arnold, P Y; Nardella, J P; White, G A

    1996-08-01

    CD4+ T cells promote immune responses against foreign Ags while actively suppressing responses against self Ags. To address how CD4+ T cells ensure self-tolerance, we focused on two CD4+ T helper cells specific for myelin basic protein (MBP). GP2.E5/R1 T cells recognized rat MBP (RMBP) as a partial agonist and mediated mild experimental autoimmune encephalomyelitis (EAE), whereas R2 T cells recognized RMBP with full efficacy and mediated severe EAE. GP2.E5/R1 T cells were more susceptible to anergy induction than R2 T cells. Anergic GP2.E5/R1 T cells lacked proliferative reactivity, but expressed both I-A glycoproteins and high levels of radioresistant APC activity. During induction of anergy, these T cells acquired the ability to present MBP. In a separate subsequent culture without further addition of Ag, anergic GP2.E5/R1 T cells elicited full proliferative and IL-2 production responses by R2 T cells. Unlike activations induced via irradiated splenocytes, irradiated anergic T cells elicited anergy in R2 T cells in the form of a postactivational phase of nonresponsiveness. Anergic GP2.E5/R1 T cells not only transferred anergy to pathogenic R2 T cells in vitro, but these anergic T cells also transferred resistance to EAE in Lewis rats subsequently challenged with guinea pig MBP in CFA. Antagonistic signaling by autologous RMBP was more tolerogenic than that of guinea pig MBP in both in vitro and in vivo models of infectious anergy. We conclude that in the presence of tolerogenic mAb, antagonistic signaling by a self protein elicited the coordinate expression of anergy and T cell-mediated APC activity as a mechanism for the genesis and spread of infectious tolerance.

  2. T cell regulation of the thymus-independent antibody response to trinitrophenylated-Brucella abortus (TNP-BA)

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    Tanay, A.; Strober, S.

    1985-06-01

    The authors have previously observed a reduction of the T cell-dependent primary antibody response to dinitrophenylated keyhole limpet hemocyanin, and an enhancement of the T cell-independent response to trinitrophenylated Brucella abortus (TNP-BA) in BALB/c mice after treatment with total lymphoid irradiation (TLI). To elucidate the relative contribution of T and B cells to the enhanced T cell-independent antibody responses after TLI, a syngeneic primary adoptive transfer system was utilized whereby irradiated hosts were reconstituted with unfractionated spleen cells or a combination of purified T and B cells from TLI-treated and untreated control mice. Antibody responses of purified splenic B cells from TLI-treated BALB/c mice (TLI/B) to TNP-BA were enhanced 10-fold as compared with those of unfractionated (UF) spleen cells or B cells from normal (NL) BALB/c mice (NL/UF and NL/B, respectively). Splenic T cells from normal animals (NL/T) suppressed the anti-TNP-BA response of TLI/B by more than 100-fold. NL/T neither suppressed nor enhanced the response of NL/B. On the other hand, T cells from TLI-treated mice (TLI/T) enhanced by 100-fold the anti-TNP-BA response of NL/B, but neither suppressed nor enhanced the response of TLI/B. Thus, T cells can regulate the T cell-independent antibody response to TNP-BA. However, experimental manipulation of the T and B cell populations is needed to demonstrate the regulatory functions.

  3. CD30 Is Dispensable for T-Cell Responses to Influenza Virus and Lymphocytic Choriomeningitis Virus Clone 13 but Contributes to Age-Associated T-Cell Expansion in Mice

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    Angela C. Zhou

    2017-09-01

    Full Text Available CD30 is a tumor necrosis factor receptor (TNFR family member whose expression is associated with Hodgkin’s disease, anaplastic large cell lymphomas, and other T and B lymphoproliferative disorders in humans. A limited number of studies have assessed the physiological role of CD30/CD30 ligand interactions in control of infection in mice. Here, we assess the role of CD30 in T-cell immunity to acute influenza and chronic lymphocytic choriomeningitis virus (LCMV clone 13 infection, two viral infections in which other members of the TNFR superfamily are important for T-cell responses. We show that CD30 is expressed on activated but not resting CD4 and CD8 T cells in vitro, as well as on regulatory T cells and marginally on T helper 1 cells in vivo during influenza infection. Despite this, CD4 and CD8 T-cell expansion in response to influenza virus was comparable in CD30+/+ and CD30−/− littermates, with no discernable role for the pathway in the outcome of influenza infection. Similarly, during persistent infection with LCMV clone 13, CD30 plays no obvious role in CD4 or CD8 T-cell responses, the level of T-cell exhaustion or viral control. In contrast, in the steady state, we observed increased numbers of total CD4 and CD8 T cells as well as increased numbers of regulatory T cells in unimmunized older (~8 months CD30+/+ but not in CD30−/− age-matched littermates. Naive T-cell numbers were unchanged in the aged CD30+/+ mice compared to their CD30−/− littermate controls, rather the T-cell expansions were explained by an increase in CD4+ and CD8+ CD44mid-hiCD62L− effector memory cells, with a similar trend in the central memory T-cell compartment. In contrast, CD30 did not impact the numbers of T cells in young mice. These data suggest a role for CD30 in the homeostatic regulation of T cells during aging, contributing to memory T-cell expansions, which may have relevance for CD30 expression in human T-cell lymphoproliferative diseases.

  4. Efficacy and toxicity management of CAR-T-cell immunotherapy: a matter of responsiveness control or tumour-specificity?

    Science.gov (United States)

    Alonso-Camino, Vanesa; Harwood, Seandean Lykke; Álvarez-Méndez, Ana; Alvarez-Vallina, Luis

    2016-04-15

    Chimaeric antigen receptor (CAR)-expressing T-cells have demonstrated potent clinical efficacy in patients with haematological malignancies. However, the use of CAR-T-cells targeting solid tumour-associated antigens (TAAs) has been limited by organ toxicities related to activation of T-cell effector functions through the CAR. Most existing CARs recognize TAAs, which are also found in normal tissues. CAR-T-cell-mediated destruction of normal tissues constitutes a major roadblock to CAR-T-cell therapy, and must be avoided or mitigated. There is a broad range of strategies for modulating antigen responsiveness of CAR-T-cells, with varying degrees of complexity. Some of them might ameliorate the acute and chronic toxicities associated with current CAR constructs. However, further embellishments to CAR therapy may complicate clinical implementation and possibly create new immunogenicity issues. In contrast, the development of CARs targeting truly tumour-specific antigens might circumvent on-target/off-tumour toxicities without adding additional complexity to CAR-T-cell therapies, but these antigens have been elusive and may require novel selection strategies for their discovery. © 2016 Authors; published by Portland Press Limited.

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

    Science.gov (United States)

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

    2016-01-01

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

  6. An Enhanced ELISPOT Assay for Sensitive Detection of Antigen-Specific T Cell Responses to Borrelia burgdorferi

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    Gottfried H. Kellermann

    2013-09-01

    Full Text Available Lyme Borreliosis is an infectious disease caused by the spirochete Borrelia burgdorferi that is transmitted through the bite of infected ticks. Both B cell-mediated humoral immunity and T cell immunity develop during natural Borrelia infection. However, compared with humoral immunity, the T cell response to Borrelia infection has not been well elucidated. In this study, a novel T cell-based assay was developed and validated for the sensitive detection of antigen-specific T cell response to B. burgdorferi. Using interferon-g as a biomarker, we developed a new enzyme-linked immunospot method (iSpot Lyme™ to detect Borrelia antigen-specific effector/memory T cells that were activated in vivo by exposing them to recombinant Borrelia antigens ex vivo. To test this new method as a potential laboratory diagnostic tool, we performed a clinical study with a cohort of Borrelia positive patients and healthy controls. We demonstrated that the iSpot Lyme assay has a significantly higher specificity and sensitivity compared with the Western Blot assay that is currently used as a diagnostic measure. A comprehensive evaluation of the T cell response to Borrelia infection should, therefore, provide new insights into the pathogenesis, diagnosis, treatment and monitoring of Lyme disease.

  7. Interplay between CD8α+ dendritic cells and monocytes in response to Listeria monocytogenes infection attenuates T cell responses.

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    Dilnawaz Kapadia

    2011-04-01

    Full Text Available During the course of a microbial infection, different antigen presenting cells (APCs are exposed and contribute to the ensuing immune response. CD8α(+ dendritic cells (DCs are an important coordinator of early immune responses to the intracellular bacteria Listeria monocytogenes (Lm and are crucial for CD8(+ T cell immunity. In this study, we examine the contribution of different primary APCs to inducing immune responses against Lm. We find that CD8α(+ DCs are the most susceptible to infection while plasmacytoid DCs are not infected. Moreover, CD8α(+ DCs are the only DC subset capable of priming an immune response to Lm in vitro and are also the only APC studied that do so when transferred into β2 microglobulin deficient mice which lack endogenous cross-presentation. Upon infection, CD11b(+ DCs primarily secrete low levels of TNFα while CD8α(+ DCs secrete IL-12 p70. Infected monocytes secrete high levels of TNFα and IL-12p70, cytokines associated with activated inflammatory macrophages. Furthermore, co-culture of infected CD8α(+ DCs and CD11b+ DCs with monocytes enhances production of IL-12 p70 and TNFα. However, the presence of monocytes in DC/T cell co-cultures attenuates T cell priming against Lm-derived antigens in vitro and in vivo. This suppressive activity of spleen-derived monocytes is mediated in part by both TNFα and inducible nitric oxide synthase (iNOS. Thus these monocytes enhance IL-12 production to Lm infection, but concurrently abrogate DC-mediated T cell priming.

  8. Vaccination targeting human HER3 alters the phenotype of infiltrating T cells and responses to immune checkpoint inhibition.

    Science.gov (United States)

    Osada, Takuya; Morse, Michael A; Hobeika, Amy; Diniz, Marcio A; Gwin, William R; Hartman, Zachary; Wei, Junping; Guo, Hongtao; Yang, Xiao-Yi; Liu, Cong-Xiao; Kaneko, Kensuke; Broadwater, Gloria; Lyerly, H Kim

    2017-01-01

    Expression of human epidermal growth factor family member 3 (HER3), a critical heterodimerization partner with EGFR and HER2, promotes more aggressive biology in breast and other epithelial malignancies. As such, inhibiting HER3 could have broad applicability to the treatment of EGFR- and HER2-driven tumors. Although lack of a functional kinase domain limits the use of receptor tyrosine kinase inhibitors, HER3 contains antigenic targets for T cells and antibodies. Using novel human HER3 transgenic mouse models of breast cancer, we demonstrate that immunization with recombinant adenoviral vectors encoding full length human HER3 (Ad-HER3-FL) induces HER3-specific T cells and antibodies, alters the T cell infiltrate in tumors, and influences responses to immune checkpoint inhibitions. Both preventative and therapeutic Ad-HER3-FL immunization delayed tumor growth but were associated with both intratumoral PD-1 expressing CD8 + T cells and regulatory CD4 + T cell infiltrates. Immune checkpoint inhibition with either anti-PD-1 or anti-PD-L1 antibodies increased intratumoral CD8 + T cell infiltration and eliminated tumor following preventive vaccination with Ad-HER3-FL vaccine. The combination of dual PD-1/PD-L1 and CTLA4 blockade slowed the growth of tumor in response to Ad-HER3-FL in the therapeutic model. We conclude that HER3-targeting vaccines activate HER3-specific T cells and induce anti-HER3 specific antibodies, which alters the intratumoral T cell infiltrate and responses to immune checkpoint inhibition.

  9. Intranasal delivery of cholera toxin induces th17-dominated T-cell response to bystander antigens.

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    Jee-Boong Lee

    Full Text Available Cholera toxin (CT is a potent vaccine adjuvant, which promotes mucosal immunity to protein antigen given by nasal route. It has been suggested that CT promotes T helper type 2 (Th2 response and suppresses Th1 response. We here report the induction of Th17-dominated responses in mice by intranasal delivery of CT. This dramatic Th17-driving effect of CT, which was dependent on the B subunit, was observed even in Th1 or Th2-favored conditions of respiratory virus infection. These dominating Th17 responses resulted in the significant neutrophil accumulation in the lungs of mice given CT. Both in vitro and in vivo treatment of CT induced strongly augmented IL-6 production, and Th17-driving ability of CT was completely abolished in IL-6 knockout mice, indicating a role of this cytokine in the Th17-dominated T-cell responses by CT. These data demonstrate a novel Th17-driving activity of CT, and help understand the mechanisms of CT adjuvanticity to demarcate T helper responses.

  10. Interplay between virus-specific effector response and Foxp3 regulatory T cells in measles virus immunopathogenesis.

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    Caroline I Sellin

    Full Text Available Measles is a highly contagious childhood disease associated with an immunological paradox: although a strong virus-specific immune response results in virus clearance and the establishment of a life-long immunity, measles infection is followed by an acute and profound immunosuppression leading to an increased susceptibility to secondary infections and high infant mortality. In certain cases, measles is followed by fatal neurological complications. To elucidate measles immunopathology, we have analyzed the immune response to measles virus in mice transgenic for the measles virus receptor, human CD150. These animals are highly susceptible to intranasal infection with wild-type measles strains. Similarly to what has been observed in children with measles, infection of suckling transgenic mice leads to a robust activation of both T and B lymphocytes, generation of virus-specific cytotoxic T cells and antibody responses. Interestingly, Foxp3(+CD25(+CD4(+ regulatory T cells are highly enriched following infection, both in the periphery and in the brain, where the virus intensively replicates. Although specific anti-viral responses develop in spite of increased frequency of regulatory T cells, the capability of T lymphocytes to respond to virus-unrelated antigens was strongly suppressed. Infected adult CD150 transgenic mice crossed in an interferon receptor type I-deficient background develop generalized immunosuppression with an increased frequency of CD4(+CD25(+Foxp3(+ T cells and strong reduction of the hypersensitivity response. These results show that measles virus affects regulatory T-cell homeostasis and suggest that an interplay between virus-specific effector responses and regulatory T cells plays an important role in measles immunopathogenesis. A better understanding of the balance between measles-induced effector and regulatory T cells, both in the periphery and in the brain, may be of critical importance in the design of novel approaches

  11. iNKT cells suppress the CD8+ T cell response to a murine Burkitt's-like B cell lymphoma.

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    Ryan L Bjordahl

    Full Text Available The T cell response to B cell lymphomas differs from the majority of solid tumors in that the malignant cells themselves are derived from B lymphocytes, key players in immune response. B cell lymphomas are therefore well situated to manipulate their surrounding microenvironment to enhance tumor growth and minimize anti-tumor T cell responses. We analyzed the effect of T cells on the growth of a transplantable B cell lymphoma and found that iNKT cells suppressed the anti-tumor CD8(+ T cell response. Lymphoma cells transplanted into syngeneic wild type (WT mice or Jalpha18(-/- mice that specifically lack iNKT cells grew initially at the same rate, but only the mice lacking iNKT cells were able to reject the lymphoma. This effect was due to the enhanced activity of tumor-specific CD8(+ T cells in the absence of iNKT cells, and could be partially reversed by reconstitution of iNKT cells in Jalpha 18(-/- mice. Treatment of tumor-bearing WT mice with alpha -galactosyl ceramide, an activating ligand for iNKT cells, reduced the number of tumor-specific CD8(+ T cells. In contrast, lymphoma growth in CD1d1(-/- mice that lack both iNKT and type II NKT cells was similar to that in WT mice, suggesting that type II NKT cells are required for full activation of the anti-tumor immune response. This study reveals a tumor-promoting role for iNKT cells and suggests their capacity to inhibit the CD8(+ T cell response to B cell lymphoma by opposing the effects of type II NKT cells.

  12. Estradiol-induced vaginal mucus inhibits antigen penetration and CD8(+) T cell priming in response to intravaginal immunization.

    Science.gov (United States)

    Seavey, Matthew M; Mosmann, Tim R

    2009-04-14

    Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8(+) T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APCs) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8(+) T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8(+) T cell priming after insemination or vaginal vaccination.

  13. Estradiol-induced vaginal mucus inhibits antigen penetration and CD8+ T cell priming in response to intravaginal immunization

    Science.gov (United States)

    Seavey, Matthew M.; Mosmann, Tim R.

    2010-01-01

    Although vaginal immunization has been explored as a strategy to induce mucosal immunity in the female reproductive tract, this site displays unique immunological features that probably evolved to inhibit anti-paternal T cell responses after insemination to allow successful pregnancy. We previously demonstrated that estradiol, which induces an estrus-like state, prevented CD8+ T cell priming during intravaginal immunization of mice. We now show that estradiol prevented antigen loading of vaginal antigen presenting cells (APC) after intravaginal immunization. Histological examination confirmed that estradiol prevented penetration of peptide antigen into the vaginal wall. Removal of the estradiol-induced mucus barrier by mucinase partially restored antigen loading of vaginal APC and CD8+ T cell proliferation in vivo. The estradiol-induced mucus barrier may thus prevent exposure to antigens delivered intravaginally, supplementing additional estradiol-dependent mechanism(s) that inhibit CD8+ T cell priming after insemination or vaginal vaccination. PMID:19428849

  14. T-cell responses targeting HIV Nef uniquely correlate with infected cell frequencies after long-term antiretroviral therapy.

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    Allison S Thomas

    2017-09-01

    Full Text Available HIV-specific CD8+ T-cell responses limit viral replication in untreated infection. After the initiation of antiretroviral therapy (ART, these responses decay and the infected cell population that remains is commonly considered to be invisible to T-cells. We hypothesized that HIV antigen recognition may persist in ART-treated individuals due to low-level or episodic protein expression. We posited that if persistent recognition were occurring it would be preferentially directed against the early HIV gene products Nef, Tat, and Rev as compared to late gene products, such as Gag, Pol, and Env, which have higher barriers to expression. Using a primary cell model of latency, we observed that a Nef-specific CD8+ T-cell clone exhibited low-level recognition of infected cells prior to reactivation and robust recognition shortly thereafter. A Gag-specific CD8+ T-cell clone failed to recognized infected cells under these conditions, corresponding with a lack of detectable Gag expression. We measured HIV-specific T-cell responses in 96 individuals who had been suppressed on ART for a median of 7 years, and observed a significant, direct correlation between cell-associated HIV DNA levels and magnitudes of IFN-γ-producing Nef/Tat/Rev-specific T-cell responses. This correlation was confirmed in an independent cohort (n = 18. Correlations were not detected between measures of HIV persistence and T-cell responses to other HIV antigens. The correlation with Nef/Tat/Rev-specific T-cells was attributable to Nef-specific responses, the breadth of which also correlated with HIV DNA levels. These results suggest that ongoing Nef expression in ART-treated individuals drives preferential maintenance and/or expansion of T-cells reactive to this protein, implying sensing of infected cells by the immune system. The direct correlation, however, suggests that recognition does not result in efficient elimination of infected cells. These results raise the possibility that

  15. Persistence of T-cell immune response induced by two acellular pertussis vaccines in children five years after primary vaccination.

    Science.gov (United States)

    Palazzo, Raffaella; Carollo, Maria; Bianco, Manuela; Fedele, Giorgio; Schiavoni, Ilaria; Pandolfi, Elisabetta; Villani, Alberto; Tozzi, Alberto E; Mascart, Françoise; Ausiello, Clara M

    2016-01-01

    The resurgence of pertussis suggests the need for greater efforts to understand the long-lasting protective responses induced by vaccination. In this paper we dissect the persistence of T memory responses induced by primary vaccination with two different acellular pertussis (aP) vaccines, hexavalent Hexavac® vaccine (Hexavac) (Sanofi Pasteur MSD) and Infanrix hexa® (Infanrix) (Glaxo-SmithKline Biologicals). We evaluated magnitude and duration of T-cell responses to pertussis toxin (PT) by measuring T-cell proliferation, cytokines (IL-2 and IFNγ) production and memory subsets in two groups of children 5 years after primary vaccination. Some of the enrolled children received only primary vaccination, while others had the pre-school boost dose. Positive T-cell responses to PT were detected in 36% of children. Percentage of responsive children, T-cell proliferation and CD4IL-2+ cells were significantly higher in the children primed with Hexavac than in those who received Infanrix vaccine. No major effects of the boost on PT-specific proliferation were observed. Overall, our data documented a persistence of T-cell memory against PT in a minor fraction of children 5 years after primary vaccination. The different responses induced by Hexavac and Infanrix vaccine could rely on differences in PT inactivation process or excipients/adjuvants formulations.

  16. T-cell Responses in Individuals Infected with Zika Virus and in Those Vaccinated Against Dengue Virus

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    Dominic Paquin-Proulx

    2017-06-01

    Full Text Available Background: The outbreak of Zika virus (ZIKV infection in Brazil has raised concerns that infection during pregnancy could cause microcephaly and other severe neurodevelopmental malformations in the fetus. The mechanisms by which ZIKV causes fetal abnormalities are largely unknown. The importance of pre-infection with dengue virus (DENV, or other flaviviruses endemic to Brazil, remains to be investigated. It has been reported that antibodies directed against DENV can increase ZIKV infectivity by antibody dependent enhancement (ADE, suggesting that a history of prior DENV infection might worsen the outcome of ZIKV infection. Methods: We used bioinformatics tools to design 18 peptides from the ZIKV envelope containing predicted HLA-I T-cell epitopes and investigated T-cell cross-reactivity between ZIKV-infected individuals and DENV-vaccinated subjects by IFNg ELISPOT. Results: Three peptides induced IFNg production in both ZIKV-infected subjects and in DENV-vaccinated individuals. Flow cytometry indicated that 1 ZIKV peptide induced a CD4+ T-cell response in DENV-vaccinated subjects. Conclusions: We demonstrated that vaccination against DENV induced a T-cell response against ZIKV and identified one such CD4+ T-cell epitope. The ZIKV-reactive CD4+ T cells induced by DENV vaccination and identified in this study could contribute to the appearance of cross-reactive antibodies mediating ADE.

  17. T-cell Responses in Individuals Infected with Zika Virus and in Those Vaccinated Against Dengue Virus.

    Science.gov (United States)

    Paquin-Proulx, Dominic; Leal, Fabio E; Terrassani Silveira, Cassia G; Maestri, Alvino; Brockmeyer, Claudia; Kitchen, Shannon M; Cabido, Vinicius D; Kallas, Esper G; Nixon, Douglas F

    2017-01-01

    The outbreak of Zika virus (ZIKV) infection in Brazil has raised concerns that infection during pregnancy could cause microcephaly and other severe neurodevelopmental malformations in the fetus. The mechanisms by which ZIKV causes fetal abnormalities are largely unknown. The importance of pre-infection with dengue virus (DENV), or other flaviviruses endemic to Brazil, remains to be investigated. It has been reported that antibodies directed against DENV can increase ZIKV infectivity by antibody dependent enhancement (ADE), suggesting that a history of prior DENV infection might worsen the outcome of ZIKV infection. We used bioinformatics tools to design 18 peptides from the ZIKV envelope containing predicted HLA-I T-cell epitopes and investigated T-cell cross-reactivity between ZIKV-infected individuals and DENV-vaccinated subjects by IFNγ ELISPOT. Three peptides induced IFNγ production in both ZIKV-infected subjects and in DENV-vaccinated individuals. Flow cytometry indicated that 1 ZIKV peptide induced a CD4+ T-cell response in DENV-vaccinated subjects. We demonstrated that vaccination against DENV induced a T-cell response against ZIKV and identified one such CD4+ T-cell epitope. The ZIKV-reactive CD4+ T cells induced by DENV vaccination and identified in this study could contribute to the appearance of cross-reactive antibodies mediating ADE.

  18. Human Neutrophil Clearance of Bacterial Pathogens Triggers Anti-Microbial γδ T Cell Responses in Early Infection

    Science.gov (United States)

    Roberts, Gareth W.; Heuston, Sinéad; Brown, Amanda C.; Chess, James A.; Toleman, Mark A.; Gahan, Cormac G. M.; Hill, Colin; Parish, Tanya; Williams, John D.; Davies, Simon J.; Johnson, David W.; Topley, Nicholas; Moser, Bernhard; Eberl, Matthias

    2011-01-01

    Human blood Vγ9/Vδ2 T cells, monocytes and neutrophils share a responsiveness toward inflammatory chemokines and are rapidly recruited to sites of infection. Studying their interaction in vitro and relating these findings to in vivo observations in patients may therefore provide crucial insight into inflammatory events. Our present data demonstrate that Vγ9/Vδ2 T cells provide potent survival signals resulting in neutrophil activation and the release of the neutrophil chemoattractant CXCL8 (IL-8). In turn, Vγ9/Vδ2 T cells readily respond to neutrophils harboring phagocytosed bacteria, as evidenced by expression of CD69, interferon (IFN)-γ and tumor necrosis factor (TNF)-α. This response is dependent on the ability of these bacteria to produce the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), requires cell-cell contact of Vγ9/Vδ2 T cells with accessory monocytes through lymphocyte function-associated antigen-1 (LFA-1), and results in a TNF-α dependent proliferation of Vγ9/Vδ2 T cells. The antibiotic fosmidomycin, which targets the HMB-PP biosynthesis pathway, not only has a direct antibacterial effect on most HMB-PP producing bacteria but also possesses rapid anti-inflammatory properties by inhibiting γδ T cell responses in vitro. Patients with acute peritoneal-dialysis (PD)-associated bacterial peritonitis – characterized by an excessive influx of neutrophils and monocytes into the peritoneal cavity – show a selective activation of local Vγ9/Vδ2 T cells by HMB-PP producing but not by HMB-PP deficient bacterial pathogens. The γδ T cell-driven perpetuation of inflammatory responses during acute peritonitis is associated with elevated peritoneal levels of γδ T cells and TNF-α and detrimental clinical outcomes in infections caused by HMB-PP positive microorganisms. Taken together, our findings indicate a direct link between invading pathogens, neutrophils, monocytes and microbe-responsive γδ T cells in early

  19. Age-Stratified T Cell Responses in Children Infected with Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Alexandra Dreesman

    2017-09-01

    Full Text Available Tuberculosis (TB in young children differs from adult TB in that the risk of rapid progression to active TB (aTB is higher in children than in adults. The reasons for this increased risk are not fully understood. Early differentiation remains difficult between children at risk to develop aTB from those who will remain healthy and develop a latent TB infection (LTBI. Biomarkers to differentiate aTB from LTBI in children, especially in very young children, are urgently needed. To identify M. tuberculosis-specific functional T cell subsets related to clinical manifestations in children, we enrolled 87 children exposed to M. tuberculosis. After standard clinical assessment, the children were classified as aTB, LTBI, or uninfected. Their CD4+ T cell cytokine profiles (IFN-γ, TNF-α, IL-2, IL-17 were analyzed at the single-cell level by flow cytometry after stimulation with three mycobacterial antigens, purified protein derivative (PPD, early-secreted-antigenic target-6 (ESAT-6, or heparin-binding hemagglutinin (HBHA. This approach identified age-related discriminative markers between aTB and LTBI. Whereas among the 3- to 15-year-old children, an excellent discrimination between aTB and LTBI was provided by comparing the ratio between the proportions of ESAT-6-induced IFN-γsingle+ and ESAT-6-induced TNF-αsingle+CD4+ T lymphocytes, this was not the case for children younger than 3 years. By contrast, in this group (<3years, the analysis of HBHA-induced IL-17single+CD4+ T lymphocytes allowed us to identify children with LTBI by the high proportion of this cellular lymphocyte subset, whereas this was not the case for children with aTB. The analysis at the single-cell level of T cell immune responses induced by mycobacterial antigens are, thus, different in infected children younger or older than 3 years of age. HBHA-induced IL-17 production by CD4+ T lymphocytes was associated with protection only in children under 3 years who are at high risk

  20. IL-10/IFNγ co-expressing CD4(+) T cells induced by IL-10 DC display a regulatory gene profile and downmodulate T cell responses

    NARCIS (Netherlands)

    Boks, Martine A.; Kager-Groenland, Judith R.; van Ham, S. Marieke; ten Brinke, Anja

    2016-01-01

    Induced regulatory T cells (iTreg) are imperative for tolerance induction and spreading of infectious tolerance. Ex vivo generated tolerogenic dendritic cells (tDCs) have strong therapeutic potential to induce antigen-specific iTreg. We previously demonstrated that IL-10 tDC-primed T cells are very

  1. Signs of impaired immunoregulation and enhanced effector T-cell responses in the primary antiphospholipid syndrome.

    Science.gov (United States)

    Jakiela, B; Iwaniec, T; Plutecka, H; Celinska-Lowenhoff, M; Dziedzina, S; Musial, J

    2016-04-01

    We investigated whether primary antiphospholipid syndrome (PAPS) is characterized by a deficiency in immunoregulatory pathways, a phenomenon recently implicated in the pathogenesis of autoimmune diseases. Serum levels of immunoregulatory (e.g., IL-10 and TGF-β1) and proinflammatory (e.g., IL-17A) cytokines were measured in PAPS, systemic lupus erythematosus (SLE) with secondary APS (SAPS), or without APS, and in healthy controls (n = 40 in each group). In a subgroup of PAPS patients we also compared phenotype and function (flow cytometry) of regulatory T-cells (Treg) and cytokine production by effector T-cells. Our major finding was decreased levels of TGF-β1 in PAPS and SAPS as compared to SLE without APS and controls. TGF-β1 was the lowest in PAPS patients showing high levels of aPL IgG with significant negative correlation with the titer. SLE patients were characterized by lower serum levels of IL-2 and increased IL-17A, as compared to the other groups. The numbers of circulating Treg cells and their phenotype (e.g., FoxP3 isoforms) were not disturbed in PAPS. However, surface expression of latency associated peptide (binds TGF-β) in activated FoxP3 + cells and in vitro production of TGF-β1 were decreased in PAPS patients with high titers of aPL IgG. Moreover, frequencies of cytokine producing effector T-helper cells (including Th17) were significantly elevated in this group. PAPS patients with high titers of aPL IgG antibodies were characterized by decreased systemic levels of TGF-β1 and its impaired production in vitro, suggesting impaired immunoregulation and enhanced adaptive autoimmune responses leading to the production of aPL antibodies. © The Author(s) 2015.

  2. Dendritic cell, monocyte and T cell activation and response to glatiramer acetate in multiple sclerosis

    DEFF Research Database (Denmark)

    Sellebjerg, F; Hesse, D; Limborg, S

    2012-01-01

    , monocytes and dendritic cells (DC) in relation to disease activity in MS patients treated with GA. Methods: Flow cytometry was used to study the activation of CD4+ T cells and T cell subsets (CD25high and CD26high cells), monocytes and DCs in a cross-sectional study of 39 untreated and 29 GA-treated MS...

  3. CD8 T-cells and E-cadherin in host responses against oropharyngeal candidiasis

    Science.gov (United States)

    Quimby, K.; Lilly, E.A.; Zacharek, M.; McNulty, K.; Leigh, J.E.; Vazquez, J.E.; Fidel, P.L.

    2011-01-01

    Oropharyngeal candidiasis (OPC) is the most common oral infection in HIV+ persons. Previous studies suggest a role for CD8+ T-cells against OPC when CD4+ T-cells are lost, but enhanced susceptibility to infection occurs when CD8+ T-cell migration is inhibited by reduced tissue E-cadherin. Objective Conduct a longitudinal study of tissue CD8+ T-cells and E-cadherin expression before, during, and after episodes of OPC. Methods Oral fungal burden was monitored and tissue was evaluated for CD8+ T-cells and E-cadherin over a one-year period in HIV+ persons with a history of, or an acute episode of OPC. Results While longitudinal analyses precluded formal interpretations, point prevalence analyses of the dataset revealed that when patients experiencing OPC were successfully treated, tissue E-cadherin expression was similar to patients who had not experienced OPC, and higher numbers of CD8+ T-cells were distributed throughout OPC− tissue under normal expression of E-cadherin. Conclusion These results suggest that 1) reduction in tissue E-cadherin expression in OPC+ patients is not permanent, and 2) high numbers of CD8+ T-cells can be distributed throughout OPC− tissue under normal E-cadherin expression. Together these results extend our previous studies and continue to support a role for CD8+ T-cells in host defense against OPC. PMID:21958417

  4. Chloroquine inhibits T cell proliferation by interfering with IL-2 production and responsiveness

    NARCIS (Netherlands)

    Landewé, R. B.; Miltenburg, A. M.; Verdonk, M. J.; Verweij, C. L.; Breedveld, F. C.; Daha, M. R.; Dijkmans, B. A.

    1995-01-01

    Chloroquine (Chl) is an anti-rheumatic drug that is widely used in the treatment of rheumatoid arthritis (RA). It seems that T cells are important in the pathogenesis of RA, but it is not known whether Chl acts via inhibition of T cell function. We here present evidence that Chl, just like

  5. Phenotypic differences of CD4(+) T cells in response to red blood cell immunization in transfused sickle cell disease patients.

    Science.gov (United States)

    Vingert, Benoît; Tamagne, Marie; Habibi, Anoosha; Pakdaman, Sadaf; Ripa, Julie; Elayeb, Rahma; Galacteros, Frédéric; Bierling, Philippe; Ansart-Pirenne, Hélène; Bartolucci, Pablo; Noizat-Pirenne, France

    2015-06-01

    Alloimmunization against red blood cells (RBCs) is the main immunological risk associated with transfusion in patients with sickle cell disease (SCD). However, about 50-70% of SCD patients never get immunized despite frequent transfusion. In murine models, CD4(+) T cells play a key role in RBC alloimmunization. We therefore explored and compared the CD4(+) T-cell phenotypes and functions between a group of SCD patients (n = 11) who never became immunized despite a high transfusion regimen and a group of SCD patients (n = 10) who had become immunized (at least against Kidd antigen b) after a low transfusion regimen. We studied markers of CD4(+) T-cell function, including TLR, that directly control lymphocyte function, and their spontaneous cytokine production. We also tested responders for the cytokine profile in response to Kidd antigen b peptides. Low TLR2/TLR3 expression and, unexpectedly, strong expression of CD40 on CD4(+) T cells were associated with the nonresponder status, whereas spontaneous expression of IL-10 by CD4(+) T cells and weak Tbet expression were associated with the responder status. A Th17 profile was predominant in responders when stimulated by Jb(k) . These findings implicate CD4(+) T cells in alloimmunization in humans and suggest that they may be exploited to differentiate responders from nonresponders. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Antigen-Experienced CD4lo T Cells Are Linked to Deficient Contraction of the Immune Response in Autoimmune Diabetes

    Directory of Open Access Journals (Sweden)

    Sean Linkes

    2010-01-01

    Full Text Available Following proper activation, naïve “CD4lo” T cells differentiate into effector T cells with enhanced expression of CD4 -“CD4hi” effectors. Autoimmune diabetes-prone NOD mice display a unique set of antigen-experienced “CD4lo” T cells that persist after primary stimulation. Here, we report that a population of such cells remained after secondary and tertiary TCR stimulation and produced cytokines upon antigenic challenge. However, when NOD blasts were induced in the presence of rIL-15, the number of antigen-experienced “CD4lo” T cells was significantly reduced. Clonal contraction, mediated in part by CD95-dependent activation-induced cell death (AICD, normally regulates the accumulation of “CD4hi” effectors. Interestingly, CD95 expression was dramatically reduced on the AICD-resistant NOD “CD4lo” T cells. Thus, while autoimmune disease has often been attributed to the engagement of robust autoimmunity, we suggest that the inability to effectively contract the immune response distinguishes benign autoimmunity from progressive autoimmune diseases that are characterized by chronic T cell-mediated inflammation.

  7. TRAV7-2*02 Expressing CD8⁺ T Cells Are Responsible for Palladium Allergy.

    Science.gov (United States)

    Takeda, Yuri; Suto, Yoshiko; Ito, Koyu; Hashimoto, Wataru; Nishiya, Tadashi; Ueda, Kyosuke; Narushima, Takayuki; Takahashi, Tetsu; Ogasawara, Kouetsu

    2017-05-31

    While metallic biomaterials have led to an improvement in the quality of life, metal allergies, especially to palladium (Pd), has caused a recent increase in allergic patients. Metal allergy is known to be a T cell-mediated delayed-type hypersensitivity (DTH); however, the pathogenic T cell subsets and the specific T cell receptor (TCR) have not been identified. Therefore, we attempted to identify the pathogenic T cells responsible for Pd allergy. We found that activating CD8⁺ T cells significantly increased and that the TRAV (TCRα variable) 7-2*02 chain skewed in Pd allergic mice. Furthermore, adoptive transfer experiments revealed that in vitro-cultured Pd-stimulated antigen presenting cells (APCs) function as memory APCs with recipient mice developing Pd allergy and that the frequency of TRAV7-2*02 increases the same as conventional Pd allergic mice. In contrast, neither proliferation of CD8⁺ T cells nor increasing of TRAV7-2*02 was observed in major histocompatibility complex I (MHC I)-deficient Pd-APCs transferred to mice. Taken together, we revealed that TRAV7-2*02-expressing CD8⁺ T cells are the pathogenic T cells for the development of Pd allergy. We also identified the CDR3 consensus motif of pathogenic TCRs as CAAXSGSWQLIF in TRAV7-2*02/TRAJ (TCRα junction)22*01 positive cells. These results suggest that the specific TCRs represent novel targets for the development of diagnostics and treatments for metal allergy.

  8. Specific immunotherapy modifies allergen-specific CD4+ T cell responses in an epitope-dependent manner

    Science.gov (United States)

    Wambre, Erik; DeLong, Jonathan H.; James, Eddie A.; Torres-Chinn, Nadia; Pfützner, Wolfgang; Möbs, Christian; Durham, Stephen R.; Till, Stephen J.; Robinson, David; Kwok, William W.

    2014-01-01

    Background Understanding the mechanisms by which the immune system induces and controls allergic inflammation at the T cell epitope level is critical for the design of new allergy vaccine strategies. Objective To characterize allergen-specific T cell responses linked with allergy or peripheral tolerance and to determine how CD4+ T cell responses to individual allergen-derived epitopes change over allergen-specific immunotherapy (ASIT). Methods Timothy grass pollen (TGP) allergy was used as a model for studying grass pollen allergies. The breadth, magnitude, epitope hierarchy and phenotype of the DR04:01-restricted TGP-specific T cell responses in ten grass pollen allergic, five non-atopic and six allergy vaccine-treated individuals was determined using an ex vivo pMHCII-tetramer approach. Results CD4+ T cells in allergic individuals are directed to a broad range of TGP epitopes characterized by defined immunodominance hierarchy patterns and with distinct functional profiles that depend on the epitope recognized. Epitopes that are restricted specifically to either TH2 or TH1/TR1 responses were identified. ASIT was associated with preferential deletion of allergen-specific TH2 cells and without significant change in frequency of TH1/TR1 cells. Conclusions Preferential allergen-specific TH2-cells deletion after repeated high doses antigen stimulation can be another independent mechanism to restore tolerance to allergen during immunotherapy. PMID:24373351

  9. Immunodominant Dengue Virus-Specific CD8+ T Cell Responses Are Associated with a Memory PD-1+ Phenotype.

    Science.gov (United States)

    de Alwis, Ruklanthi; Bangs, Derek J; Angelo, Michael A; Cerpas, Cristhiam; Fernando, Anira; Sidney, John; Peters, Bjoern; Gresh, Lionel; Balmaseda, Angel; de Silva, Aruna D; Harris, Eva; Sette, Alessandro; Weiskopf, Daniela

    2016-05-01

    Dengue disease is a large public health problem that mainly afflicts tropical and subtropical regions. Understanding of the correlates of protection against dengue virus (DENV) is poor and hinders the development of a successful human vaccine. The present study aims to define DENV-specific CD8(+)T cell responses in general and those of HLA alleles associated with dominant responses in particular. In human blood donors in Nicaragua, we observed a striking dominance of HLA B-restricted responses in general and of the allele B*35:01 in particular. Comparing these patterns to those in the general population of Sri Lanka, we found a strong correlation between restriction of the HLA allele and the breadth and magnitude of CD8(+)T cell responses, suggesting that HLA genes profoundly influence the nature of responses. The majority of gamma interferon (IFN-γ) responses were associated with effector memory phenotypes, which were also detected in non-B*35:01-expressing T cells. However, only the B*35:01 DENV-specific T cells were associated with marked expression of the programmed death 1 protein (PD-1). These cells did not coexpress other inhibitory receptors and were able to proliferate in response to DENV-specific stimulation. Thus, the expression of particular HLA class I alleles is a defining characteristic influencing the magnitude and breadth of CD8 responses, and a distinct, highly differentiated phenotype is specifically associated with dominant CD8(+)T cells. These results are of relevance for both vaccine design and the identification of robust correlates of protection in natural immunity. Dengue is an increasingly significant public health problem as its mosquito vectors spread over greater areas; no vaccines against the virus have yet been approved. An important step toward vaccine development is defining protective immune responses; toward that end, we here characterize the phenotype of the immunodominant T cell responses. These DENV-reactive T cells express

  10. Prospective analysis of human cytomegalovirus DNAemia and specific CD8+ T cell responses in lung transplant recipients.

    Science.gov (United States)

    Weseslindtner, L; Kerschner, H; Steinacher, D; Nachbagauer, R; Kundi, M; Jaksch, P; Simon, B; Hatos-Agyi, L; Scheed, A; Klepetko, W; Puchhammer-Stöckl, E

    2012-08-01

    In lung transplant recipients (LuTRs), human cytomegalovirus (HCMV) DNAemia may be associated with HCMV disease and reduced survival of the allograft. Because T cells are essential for controlling HCMV replication, we investigated in this prospective study whether the kinetics of plasma HCMV DNA loads in LuTRs are associated with HCMV-specific CD8+ T cell responses, which were longitudinally assessed using a standardized assay. Sixty-seven LuTRs were monitored during the first year posttransplantation, with a mean of 17 HCMV DNA PCR quantifications and 11.5 CD8+ T cell tests performed per patient. HCMV-specific CD8+ T cell responses displayed variable kinetics in different patients, differed significantly before the onset of HCMV DNAemia in LuTRs who subsequently experienced episodes of DNAemia with high (>1000 copies/mL) and low plasma DNA levels (p = 0.0046, Fisher's exact test), and were absent before HCMV disease. In HCMV-seropositive LuTRs, high-level DNAemia requiring preemptive therapy occurred more frequently when HCMV-specific CD8+ T cell responses fluctuated, were detected only after HCMV DNA detection, or remained undetectable (p = 0.0392, Fisher's exact test). Thus, our data indicate that HCMV-specific CD8+ T cells influence the magnitude of HCMV DNAemia episodes, and we propose that a standardized measurement of CD8+ T cell immunity might contribute to monitoring the immune status of LuTRs posttransplantation. © Copyright 2012 The American Society of Transplantation and the American Society of Transplant Surgeons.

  11. Persistent enteric murine norovirus infection is associated with functionally suboptimal virus-specific CD8 T cell responses.

    Science.gov (United States)

    Tomov, Vesselin T; Osborne, Lisa C; Dolfi, Douglas V; Sonnenberg, Gregory F; Monticelli, Laurel A; Mansfield, Kathleen; Virgin, Herbert W; Artis, David; Wherry, E John

    2013-06-01

    Norovirus (NV) gastroenteritis is a major contributor to global morbidity and mortality, yet little is known about immune mechanisms leading to NV control. Previous studies using the murine norovirus (MNV) model have established a key role for T cells in MNV clearance. Despite these advances, important questions remain regarding the magnitude, location, and dynamics of the MNV-specific T cell response. To address these questions, we identified MNV-specific major histocompatibility complex (MHC) class I immunodominant epitopes using an overlapping peptide screen. One of these epitopes (amino acids 519 to 527 of open reading frame 2 [ORF2(519-527)]) was highly conserved among all NV genogroups. Using MHC class I peptide tetramers, we tracked MNV-specific CD8 T cells in lymphoid and mucosal sites during infection with two MNV strains with distinct biological behaviors, the acutely cleared strain CW3 and the persistent strain CR6. Here, we show that enteric MNV infection elicited robust T cell responses primarily in the intestinal mucosa and that MNV-specific CD8 T cells dynamically regulated the expression of surface molecules associated with activation, differentiation, and homing. Furthermore, compared to MNV-CW3 infection, chronic infection with MNV-CR6 resulted in fewer and less-functional CD8 T cells, and this difference was evident as early as day 8 postinfection. Finally, MNV-specific CD8 T cells were capable of reducing the viral load in persistently infected Rag1(-/-) mice, suggesting that these cells are a crucial component of NV immunity. Collectively, these data provide fundamental new insights into the adaptive immune response to two closely related NV strains with distinct biological behaviors and bring us closer to understanding the correlates of protective antiviral immunity in the intestine.

  12. Effective CD4+ T-cell restoration in gut-associated lymphoid tissue of HIV-infected patients is associated with enhanced Th17 cells and polyfunctional HIV-specific T-cell responses.

    Science.gov (United States)

    Macal, M; Sankaran, S; Chun, T-W; Reay, E; Flamm, J; Prindiville, T J; Dandekar, S

    2008-11-01

    Human immunodeficiency virus (HIV) infection leads to severe CD4+ T-cell depletion in gut-associated lymphoid tissue (GALT) that persists despite the initiation of highly active antiretroviral therapy (HAART). It is not known whether restoration of gut mucosal CD4+ T cells and their functions is feasible during therapy and how that relates to immune correlates and viral reservoirs. Intestinal biopsies and peripheral blood samples from HIV-infected patients who were either HAART naive or on long-term HAART were evaluated. Our data demonstrated that gut CD4+ T-cell restoration ranged from modest (50%), compared with uninfected controls. Despite persistent CD4+ T-cell proviral burden and residual immune activation in GALT during HAART, effective CD4+ T-cell restoration (>50%) was achieved, which was associated with enhanced Th17 CD4+ T-cell accumulation and polyfunctional anti-HIV cellular responses. Our findings suggest that a threshold of>50% CD4+ T-cell restoration may be sufficient for polyfunctional HIV-specific T cells with implications in the evaluation of vaccines and therapeutics.

  13. PD-L1 Expression Induced by the 2009 Pandemic Influenza A(H1N1 Virus Impairs the Human T Cell Response

    Directory of Open Access Journals (Sweden)

    Nuriban Valero-Pacheco

    2013-01-01

    Full Text Available PD-L1 expression plays a critical role in the impairment of T cell responses during chronic infections; however, the expression of PD-L1 on T cells during acute viral infections, particularly during the pandemic influenza virus (A(H1N1pdm09, and its effects on the T cell response have not been widely explored. We found that A(H1N1pdm09 virus induced PD-L1 expression on human dendritic cells (DCs and T cells, as well as PD-1 expression on T cells. PD-L1 expression impaired the T cell response against A(H1N1pdm09 by promoting CD8+ T cell death and reducing cytokine production. Furthermore, we found increased PD-L1 expression on DCs and T cells from influenza-infected patients from the first and second 2009 pandemic waves in Mexico City. PD-L1 expression on CD8+ T cells correlated inversely with T cell proportions in patients infected with A(H1N1pdm09. Therefore, PD-L1 expression on DCs and T cells could be associated with an impaired T cell response during acute infection with A(H1N1pdm09 virus.

  14. A statistical framework for modeling HLA-dependent T cell response data.

    Directory of Open Access Journals (Sweden)

    Jennifer Listgarten

    2007-10-01

    Full Text Available The identification of T cell epitopes and their HLA (human leukocyte antigen restrictions is important for applications such as the design of cellular vaccines for HIV. Traditional methods for such identification are costly and time-consuming. Recently, a more expeditious laboratory technique using ELISpot assays has been developed that allows for rapid screening of specific responses. However, this assay does not directly provide information concerning the HLA restriction of a response, a critical piece of information for vaccine design. Thus, we introduce, apply, and validate a statistical model for identifying HLA-restricted epitopes from ELISpot data. By looking at patterns across a broad range of donors, in conjunction with our statistical model, we can determine (probabilistically which of the HLA alleles are likely to be responsible for the observed reactivities. Additionally, we can provide a good estimate of the number of false positives generated by our analysis (i.e., the false discovery rate. This model allows us to learn about new HLA-restricted epitopes from ELISpot data in an efficient, cost-effective, and high-throughput manner. We applied our approach to data from donors infected with HIV and identified many potential new HLA restrictions. Among 134 such predictions, six were confirmed in the lab and the remainder could not be ruled as invalid. These results shed light on the extent of HLA class I promiscuity, which has significant implications for the understanding of HLA class I antigen presentation and vaccine development.

  15. Breadth of T cell responses after immunization with adenovirus vectors encoding ancestral antigens or polyvalent papillomavirus antigens

    DEFF Research Database (Denmark)

    Ragonnaud, Emeline; Pedersen, Anders Gorm; Holst, Peter Johannes

    2017-01-01

    - either by inducing cross-reactive T cells or by administering a polyvalent vaccine. To test these strategies, we designed 3 ancestral and 2 circulating sequences based on the two domains of the E1 and E2 proteins of papillomaviruses (PVs) that exhibit the highest degree of conservation in comparison...... circulating strains and a putative ancestor of oncogenic HPVs, we showed that the ancestral vaccine antigen has to be approximately 90% identical to the circulating PVs before a marked drop of ~90% mean CD8+ T cell responses ensues. Interestingly, the combination of two or three type-specific PV vaccines did...... not induce a significant decrease of the CD8+ T cell response to the individual targeted PV types. Polyvalent HPV vaccine based on the E1 and E2 proteins seem to be capable of triggering responses towards more than one type of PV while the cross-reactivity of ancestral vaccine seems insufficient...

  16. Triggering DTH and CTL activity by fd filamentous bacteriophages: role of CD4+ T cells in memory responses.

    Science.gov (United States)

    Del Pozzo, Giovanna; Mascolo, Dina; Sartorius, Rossella; Citro, Alessandra; Barba, Pasquale; D'Apice, Luciana; De Berardinis, Piergiuseppe

    2010-01-01

    The ability of fd bacteriophage particles to trigger different arms of the immune system has been previously shown by us with particular emphasis on the ability of phages to raise CTL responses in vitro and in vivo. Here we show that fd virions in the absence of adjuvants are able to evoke a DTH reaction mediated by antigen specific CD8+ T cells. In addition, we analyzed the induction of CTL responses in mice depleted of CD4+ T cells, and we observed that short-term secondary CTL responses were induced in the absence of CD4+ T cells while induction of long-term memory CTLs required the presence of CD4+ T lymphocytes. These results examine the cellular mechanism at the basis of fd efficiency and provide new elements to further validate the use of fd particles for eliciting and monitoring antigen-specific CTLs.

  17. In Vitro Use of Autologous Dendritic Cells Improves Detection of T Cell Responses to Hepatitis B Virus (HBV) Antigens

    NARCIS (Netherlands)

    Carotenuto, Patrizia; Artsen, Andre; Niesters, Hubert G.; Osterhaus, Albert D.; Pontesilli, Oscar

    T lymphocyte responses to hepatitis B virus (HBV) core antigen (HBcAg) are vigorous and easily detectable in vitro during recovery from acute hepatitis B but significantly weaker in patients with chronic HBV infection. In contrast, T cell responses to hepatitis B surface antigen (HBsAg) are almost

  18. Characterization of the specific CD4+ T cell response against the F protein during chronic hepatitis C virus infection.

    Directory of Open Access Journals (Sweden)

    De-Yong Gao

    Full Text Available BACKGROUND: The hepatitis C virus (HCV Alternate Reading Frame Protein (ARFP or F protein presents a double-frame shift product of the HCV core gene. We and others have previously reported that the specific antibodies against the F protein could be raised in the sera of HCV chronically infected patients. However, the specific CD4(+ T cell responses against the F protein during HCV infection and the pathological implications remained unclear. In the current study, we screened the MHC class II-presenting epitopes of the F protein through HLA-transgenic mouse models and eventually validated the specific CD4(+ T cell responses in HCV chronically infected patients. METHODOLOGY: DNA vaccination in HLA-DR1 and-DP4 transgenic mouse models, proliferation assay to test the F protein specific T cell response, genotyping of Chronic HCV patients and testing the F-peptide stimulated T cell response in the peripheral blood mononuclear cell (PBMC by in vitro expansion and interferon (IFN- γ intracellular staining. PRINCIPAL FINDINGS: At least three peptides within HCV F protein were identified as HLA-DR or HLA-DP4 presenting epitopes by the proliferation assays in mouse models. Further study with human PBMCs evidenced the specific CD4(+ T cell responses against HCV F protein as well in patients chronically infected with HCV. CONCLUSION: The current study provided the evidence for the first time that HCV F protein could elicit specific CD4(+ T cell response, which may provide an insight into the immunopathogenesis during HCV chronic infection.

  19. Functional phenotype of synovial monocytes modulating inflammatory T-cell responses in rheumatoid arthritis (RA.

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    Bo Ruem Yoon

    Full Text Available Monocytes function as crucial innate effectors in the pathogenesis of chronic inflammatory diseases, including autoimmunity, as well as in the inflammatory response against infectious pathogens. Human monocytes are heterogeneous and can be classified into three distinct subsets based on CD14 and CD16 expression. Although accumulating evidence suggests distinct functions of monocyte subsets in inflammatory conditions, their pathogenic roles in autoimmune diseases remain unclear. Thus, we investigated the phenotypic and functional characteristics of monocytes derived from synovial fluid and peripheral blood in RA patients in order to explore the pathogenic roles of these cells. In RA patients, CD14+CD16+, but not CD14dimCD16+, monocytes are predominantly expanded in synovial fluid and, to a lesser degree, in peripheral blood. Expression of co-signaling molecules of the B7 family, specifically CD80 and CD276, was markedly elevated on synovial monocytes, while peripheral monocytes of RA and healthy controls did not express these molecules without stimulation. To explore how synovial monocytes might gain these unique properties in the inflammatory milieu of the synovial fluid, peripheral monocytes were exposed to various stimuli. CD16 expression on CD14+ monocytes was clearly induced by TGF-β, although co-treatment with IL-1β, TNF-α, or IL-6 did not result in any additive effects. In contrast, TLR stimulation with LPS or zymosan significantly downregulated CD16 expression such that the CD14+CD16+ monocyte subset could not be identified. Furthermore, treatment of monocytes with IFN-γ resulted in the induction of CD80 and HLA-DR expression even in the presence of TGF-β. An in vitro assay clearly showed that synovial monocytes possess the unique capability to promote Th1 as well as Th17 responses of autologous peripheral CD4 memory T cells. Our findings suggest that the cytokine milieu of the synovial fluid shapes the unique features of synovial

  20. Chitin recognition via chitotriosidase promotes pathologic type-2 helper T cell responses to cryptococcal infection.

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    Darin L Wiesner

    2015-03-01

    Full Text Available Pulmonary mycoses are often associated with type-2 helper T (Th2 cell responses. However, mechanisms of Th2 cell accumulation are multifactorial and incompletely known. To investigate Th2 cell responses to pulmonary fungal infection, we developed a peptide-MHCII tetramer to track antigen-specific CD4+ T cells produced in response to infection with the fungal pathogen Cryptococcus neoformans. We noted massive accruement of pathologic cryptococcal antigen-specific Th2 cells in the lungs following infection that was coordinated by lung-resident CD11b+ IRF4-dependent conventional dendritic cells. Other researchers have demonstrated that this dendritic cell subset is also capable of priming protective Th17 cell responses to another pulmonary fungal infection, Aspergillus fumigatus. Thus, higher order detection of specific features of fungal infection by these dendritic cells must direct Th2 cell lineage commitment. Since chitin-containing parasites commonly elicit Th2 responses, we hypothesized that recognition of fungal chitin is an important determinant of Th2 cell-mediated mycosis. Using C. neoformans mutants or purified chitin, we found that chitin abundance impacted Th2 cell accumulation and disease. Importantly, we determined Th2 cell induction depended on cleavage of chitin via the mammalian chitinase, chitotriosidase, an enzyme that was also prevalent in humans experiencing overt cryptococcosis. The data presented herein offers a new perspective on fungal disease susceptibility, whereby chitin recognition via chitotriosidase leads to the initiation of harmful Th2 cell differentiation by CD11b+ conventional dendritic cells in response to pulmonary fungal infection.

  1. Chitin Recognition via Chitotriosidase Promotes Pathologic Type-2 Helper T Cell Responses to Cryptococcal Infection

    Science.gov (United States)

    Wiesner, Darin L.; Specht, Charles A.; Lee, Chrono K.; Smith, Kyle D.; Mukaremera, Liliane; Lee, S. Thera; Lee, Chun G.; Elias, Jack A.; Nielsen, Judith N.; Boulware, David R.; Bohjanen, Paul R.; Jenkins, Marc K.; Levitz, Stuart M.; Nielsen, Kirsten

    2015-01-01

    Pulmonary mycoses are often associated with type-2 helper T (Th2) cell responses. However, mechanisms of Th2 cell accumulation are multifactorial and incompletely known. To investigate Th2 cell responses to pulmonary fungal infection, we developed a peptide-MHCII tetramer to track antigen-specific CD4+ T cells produced in response to infection with the fungal pathogen Cryptococcus neoformans. We noted massive accruement of pathologic cryptococcal antigen-specific Th2 cells in the lungs following infection that was coordinated by lung-resident CD11b+ IRF4-dependent conventional dendritic cells. Other researchers have demonstrated that this dendritic cell subset is also capable of priming protective Th17 cell responses to another pulmonary fungal infection, Aspergillus fumigatus. Thus, higher order detection of specific features of fungal infection by these dendritic cells must direct Th2 cell lineage commitment. Since chitin-containing parasites commonly elicit Th2 responses, we hypothesized that recognition of fungal chitin is an important determinant of Th2 cell-mediated mycosis. Using C. neoformans mutants or purified chitin, we found that chitin abundance impacted Th2 cell accumulation and disease. Importantly, we determined Th2 cell induction depended on cleavage of chitin via the mammalian chitinase, chitotriosidase, an enzyme that was also prevalent in humans experiencing overt cryptococcosis. The data presented herein offers a new perspective on fungal disease susceptibility, whereby chitin recognition via chitotriosidase leads to the initiation of harmful Th2 cell differentiation by CD11b+ conventional dendritic cells in response to pulmonary fungal infection. PMID:25764512

  2. Sequential Dysfunction and Progressive Depletion of Candida albicans-Specific CD4 T Cell Response in HIV-1 Infection

    Science.gov (United States)

    Liu, Fengliang; Fan, Xiuzhen; Auclair, Sarah; Ferguson, Monique; Sun, Jiaren; Soong, Lynn; Hou, Wei; Redfield, Robert R.; Birx, Deborah L.; Ratto-Kim, Silvia; Robb, Merlin L.; Kim, Jerome H.; Michael, Nelson L.; Hu, Haitao

    2016-01-01

    Loss of immune control over opportunistic infections can occur at different stages of HIV-1 (HIV) disease, among which mucosal candidiasis caused by the fungal pathogen Candida albicans (C. albicans) is one of the early and common manifestations in HIV-infected human subjects. The underlying immunological basis is not well defined. We have previously shown that compared to cytomegalovirus (CMV)-specific CD4 cells, C. albicans-specific CD4 T cells are highly permissive to HIV in vitro. Here, based on an antiretroviral treatment (ART) naïve HIV infection cohort (RV21), we investigated longitudinally the impact of HIV on C. albicans- and CMV-specific CD4 T-cell immunity in vivo. We found a sequential dysfunction and preferential depletion for C. albicans-specific CD4 T cell response during progressive HIV infection. Compared to Th1 (IFN-γ, MIP-1β) functional subsets, the Th17 functional subsets (IL-17, IL-22) of C. albicans-specific CD4 T cells were more permissive to HIV in vitro and impaired earlier in HIV-infected subjects. Infection history analysis showed that C. albicans-specific CD4 T cells were more susceptible to HIV in vivo, harboring modestly but significantly higher levels of HIV DNA, than CMV-specific CD4 T cells. Longitudinal analysis of HIV-infected individuals with ongoing CD4 depletion demonstrated that C. albicans-specific CD4 T-cell response was preferentially and progressively depleted. Taken together, these data suggest a potential mechanism for earlier loss of immune control over mucosal candidiasis in HIV-infected patients and provide new insights into pathogen-specific immune failure in AIDS pathogenesis. PMID:27280548

  3. The Subcellular Location of Ovalbumin in Plasmodium berghei Blood Stages Influences the Magnitude of T-Cell Responses

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    Lin, Jing-Wen; Shaw, Tovah N.; Annoura, Takeshi; Fougère, Aurélie; Bouchier, Pascale; Chevalley-Maurel, Séverine; Kroeze, Hans; Franke-Fayard, Blandine; Janse, Chris J.; Couper, Kevin N.

    2014-01-01

    Model antigens are frequently introduced into pathogens to study determinants that influence T-cell responses to infections. To address whether an antigen's subcellular location influences the nature and magnitude of antigen-specific T-cell responses, we generated Plasmodium berghei parasites expressing the model antigen ovalbumin (OVA) either in the parasite cytoplasm or on the parasitophorous vacuole membrane (PVM). For cytosolic expression, OVA alone or conjugated to mCherry was expressed from a strong constitutive promoter (OVAhsp70 or OVA::mCherryhsp70); for PVM expression, OVA was fused to HEP17/EXP1 (OVA::Hep17hep17). Unexpectedly, OVA expression in OVAhsp70 parasites was very low, but when OVA was fused to mCherry (OVA::mCherryhsp70), it was highly expressed. OVA expression in OVA::Hep17hep17 parasites was strong but significantly less than that in OVA::mCherryhsp70 parasites. These transgenic parasites were used to examine the effects of antigen subcellular location and expression level on the development of T-cell responses during blood-stage infections. While all OVA-expressing parasites induced activation and proliferation of OVA-specific CD8+ T cells (OT-I) and CD4+ T cells (OT-II), the level of activation varied: OVA::Hep17hep17 parasites induced significantly stronger splenic and intracerebral OT-I and OT-II responses than those of OVA::mCherryhsp70 parasites, but OVA::mCherryhsp70 parasites promoted stronger OT-I and OT-II responses than those of OVAhsp70 parasites. Despite lower OVA expression levels, OVA::Hep17hep17 parasites induced stronger T-cell responses than those of OVA::mCherryhsp70 parasites. These results indicate that unconjugated cytosolic OVA is not stably expressed in Plasmodium parasites and, importantly, that its cellular location and expression level influence both the induction and magnitude of parasite-specific T-cell responses. These parasites represent useful tools for studying the development and function of antigen

  4. Antibody and T-cell responses associated with experimental human malaria infection or vaccination show limited relationships.

    Science.gov (United States)

    Walker, Karen M; Okitsu, Shinji; Porter, David W; Duncan, Christopher; Amacker, Mario; Pluschke, Gerd; Cavanagh, David R; Hill, Adrian V S; Todryk, Stephen M

    2015-05-01

    This study examined specific antibody and T-cell responses associated with experimental malaria infection or malaria vaccination, in malaria-naive human volunteers within phase I/IIa vaccine trials, with a view to investigating inter-relationships between these types of response. Malaria infection was via five bites of Plasmodium falciparum-infected mosquitoes, with individuals reaching patent infection by 11-12 days, having harboured four or five blood-stage cycles before drug clearance. Infection elicited a robust antibody response against merozoite surface protein-119 , correlating with parasite load. Classical class switching was seen from an early IgM to an IgG1-dominant response of increasing affinity. Malaria-specific T-cell responses were detected in the form of interferon-γ and interleukin-4 (IL-4) ELIspot, but their magnitude did not correlate with the magnitude of antibody or its avidity, or with parasite load. Different individuals who were immunized with a virosome vaccine comprising influenza antigens combined with P. falciparum antigens, demonstrated pre-existing interferon-γ, IL-2 and IL-5 ELIspot responses against the influenza antigens, and showed boosting of anti-influenza T-cell responses only for IL-5. The large IgG1-dominated anti-parasite responses showed limited correlation with T-cell responses for magnitude or avidity, both parameters being only negatively correlated for IL-5 secretion versus anti-apical membrane antigen-1 antibody titres. Overall, these findings suggest that cognate T-cell responses across a range of magnitudes contribute towards driving potentially effective antibody responses in infection-induced and vaccine-induced immunity against malaria, and their existence during immunization is beneficial, but magnitudes are mostly not inter-related. © 2014 John Wiley & Sons Ltd.

  5. Functional Specialization of Skin Dendritic Cell Subsets in Regulating T Cell Responses

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    Clausen, Björn E.; Stoitzner, Patrizia

    2015-01-01

    Dendritic cells (DC) are a heterogeneous family of professional antigen-presenting cells classically recognized as most potent inducers of adaptive immune responses. In this respect, Langerhans cells have long been considered to be prototypic immunogenic DC in the skin. More recently this view has considerably changed. The generation of in vivo cell ablation and lineage tracing models revealed the complexity of the skin DC network and, in particular, established the existence of a number of phenotypically distinct Langerin+ and negative DC populations in the dermis. Moreover, by now we appreciate that DC also exert important regulatory functions and are required for the maintenance of tolerance toward harmless foreign and self-antigens. This review summarizes our current understanding of the skin-resident DC system in the mouse and discusses emerging concepts on the functional specialization of the different skin DC subsets in regulating T cell responses. Special consideration is given to antigen cross-presentation as well as immune reactions toward contact sensitizers, cutaneous pathogens, and tumors. These studies form the basis for the manipulation of the human counterparts of the murine DC subsets to promote immunity or tolerance for the treatment of human disease. PMID:26557117

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

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    Raquel Tayar Nogueira

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

  7. Association of Neisseria gonorrhoeae Opa(CEA with dendritic cells suppresses their ability to elicit an HIV-1-specific T cell memory response.

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    Qigui Yu

    Full Text Available Infection with Neisseria gonorrhoeae (N. gonorrhoeae can trigger an intense local inflammatory response at the site of infection, yet there is little specific immune response or development of immune memory. Gonococcal surface epitopes are known to undergo antigenic variation; however, this is unlikely to explain the weak immune response to infection since individuals can be re-infected by the same serotype. Previous studies have demonstrated that the colony opacity-associated (Opa proteins on the N. gonorrhoeae surface can bind human carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1 on CD4⁺ T cells to suppress T cell activation and proliferation. Interesting in this regard, N. gonorrhoeae infection is associated with impaired HIV-1 (human immunodeficiency virus type 1-specific cytotoxic T-lymphocyte (CTL responses and with transient increases in plasma viremia in HIV-1-infected patients, suggesting that N. gonorrhoeae may also subvert immune responses to co-pathogens. Since dendritic cells (DCs are professional antigen presenting cells (APCs that play a key role in the induction of an adaptive immune response, we investigated the effects of N. gonorrhoeae Opa proteins on human DC activation and function. While morphological changes reminiscent of DC maturation were evident upon N. gonorrhoeae infection, we observed a marked downregulation of DC maturation marker CD83 when the gonococci expressing CEACAM1-specific Opa(CEA, but not other Opa variants. Consistent with a gonococcal-induced defect in maturation, Opa(CEA binding to CEACAM1 reduced the DCs' capacity to stimulate an allogeneic T cell proliferative response. Moreover, Opa(CEA-expressing N. gonorrhoeae showed the potential to impair DC-dependent development of specific adaptive immunity, since infection with Opa(CEA-positive gonococci suppressed the ability of DCs to stimulate HIV-1-specific memory CTL responses. These results reveal a novel mechanism to explain

  8. Association of Neisseria gonorrhoeae Opa(CEA) with dendritic cells suppresses their ability to elicit an HIV-1-specific T cell memory response.

    Science.gov (United States)

    Yu, Qigui; Chow, Edith M C; McCaw, Shannon E; Hu, Ningjie; Byrd, Daniel; Amet, Tohti; Hu, Sishun; Ostrowski, Mario A; Gray-Owen, Scott D

    2013-01-01

    Infection with Neisseria gonorrhoeae (N. gonorrhoeae) can trigger an intense local inflammatory response at the site of infection, yet there is little specific immune response or development of immune memory. Gonococcal surface epitopes are known to undergo antigenic variation; however, this is unlikely to explain the weak immune response to infection since individuals can be re-infected by the same serotype. Previous studies have demonstrated that the colony opacity-associated (Opa) proteins on the N. gonorrhoeae surface can bind human carcinoembryonic antigen-related cellular adhesion molecule 1 (CEACAM1) on CD4⁺ T cells to suppress T cell activation and proliferation. Interesting in this regard, N. gonorrhoeae infection is associated with impaired HIV-1 (human immunodeficiency virus type 1)-specific cytotoxic T-lymphocyte (CTL) responses and with transient increases in plasma viremia in HIV-1-infected patients, suggesting that N. gonorrhoeae may also subvert immune responses to co-pathogens. Since dendritic cells (DCs) are professional antigen presenting cells (APCs) that play a key role in the induction of an adaptive immune response, we investigated the effects of N. gonorrhoeae Opa proteins on human DC activation and function. While morphological changes reminiscent of DC maturation were evident upon N. gonorrhoeae infection, we observed a marked downregulation of DC maturation marker CD83 when the gonococci expressing CEACAM1-specific Opa(CEA), but not other Opa variants. Consistent with a gonococcal-induced defect in maturation, Opa(CEA) binding to CEACAM1 reduced the DCs' capacity to stimulate an allogeneic T cell proliferative response. Moreover, Opa(CEA)-expressing N. gonorrhoeae showed the potential to impair DC-dependent development of specific adaptive immunity, since infection with Opa(CEA)-positive gonococci suppressed the ability of DCs to stimulate HIV-1-specific memory CTL responses. These results reveal a novel mechanism to explain why

  9. Protective Efficacy in Sheep of Adenovirus-Vectored Vaccines against Bluetongue Virus Is Associated with Specific T Cell Responses

    Science.gov (United States)

    Martín, Verónica; Pascual, Elena; Avia, Miguel; Peña, Lourdes; Valcárcel, Félix; Sevilla, Noemí

    2015-01-01

    Bluetongue virus (BTV) is an economically important Orbivirus of the Reoviridae family that causes a hemorrhagic disease in ruminants. Its control has been achieved by inactivated-vaccines that have proven to protect against homologous BTV challenge although unable to induce long-term immunity. Therefore, a more efficient control strategy needs to be developed. Recombinant adenovirus vectors are lead vaccine candidates for protection of several diseases, mainly because of their potency to induce potent T cell immunity. Here we report the induction of humoral and T-cell mediated responses able to protect animals against BTV challenge by recombinant replication-defective human adenovirus serotype 5 (Ad5) expressing either VP7, VP2 or NS3 BTV proteins. First we used the IFNAR(-/-) mouse model system to establish a proof of principle, and afterwards we assayed the protective efficacy in sheep, the natural host of BTV. Mice were completely protected against BTV challenge, developing humoral and BTV-specific CD8+- and CD4+-T cell responses by vaccination with the different rAd5. Sheep vaccinated with Ad5-BTV-VP2 and Ad5-BTV-VP7 or only with Ad5-BTV-VP7 and challenged with BTV showed mild disease symptoms and reduced viremia. This partial protection was achieved in the absence of neutralizing antibodies but strong BTV-specific CD8+ T cell responses in those sheep vaccinated with Ad5-BTV-VP7. These data indicate that rAd5 is a suitable vaccine vector to induce T cell immunity during BTV vaccination and provide new data regarding the relevance of T cell responses in protection during BTV infection. PMID:26619062

  10. A DNA vaccine encoding multiple HIV CD4 epitopes elicits vigorous polyfunctional, long-lived CD4+ and CD8+ T cell responses.

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    Daniela Santoro Rosa

    Full Text Available T-cell based vaccines against HIV have the goal of limiting both transmission and disease progression by inducing broad and functionally relevant T cell responses. Moreover, polyfunctional and long-lived specific memory T cells have been associated to vaccine-induced protection. CD4(+ T cells are important for the generation and maintenance of functional CD8(+ cytotoxic T cells. We have recently developed a DNA vaccine encoding 18 conserved multiple HLA-DR-binding HIV-1 CD4 epitopes (HIVBr18, capable of eliciting broad CD4(+ T cell responses in multiple HLA class II transgenic mice. Here, we evaluated the breadth and functional profile of HIVBr18-induced immune responses in BALB/c mice. Immunized mice displayed high-magnitude, broad CD4(+/CD8(+ T cell responses, and 8/18 vaccine-encoded peptides were recognized. In addition, HIVBr18 immunization was able to induce polyfunctional CD4(+ and CD8(+ T cells that proliferate and produce any two cytokines (IFNγ/TNFα, IFNγ/IL-2 or TNFα/IL-2 simultaneously in response to HIV-1 peptides. For CD4(+ T cells exclusively, we also detected cells that proliferate and produce all three tested cytokines simultaneously (IFNγ/TNFα/IL-2. The vaccine also generated long-lived central and effector memory CD4(+ T cells, a desirable feature for T-cell based vaccines. By virtue of inducing broad, polyfunctional and long-lived T cell responses against conserved CD4(+ T cell epitopes, combined administration of this vaccine concept may provide sustained help for CD8(+ T cells and antibody responses- elicited by other HIV immunogens.

  11. Transfer of mRNA Encoding Invariant NKT Cell Receptors Imparts Glycolipid Specific Responses to T Cells and γδT Cells.

    Science.gov (United States)

    Shimizu, Kanako; Shinga, Jun; Yamasaki, Satoru; Kawamura, Masami; Dörrie, Jan; Schaft, Niels; Sato, Yusuke; Iyoda, Tomonori; Fujii, Shin-Ichiro

    2015-01-01

    Cell-based therapies using genetically engineered lymphocytes expressing antigen-specific T cell receptors (TCRs) hold promise for the treatment of several types of cancers. Almost all studies using this modality have focused on transfer of TCR from CD8 cytotoxic T lymphocytes (CTLs). The transfer of TCR from innate lymphocytes to other lymphocytes has not been studied. In the current study, innate and adaptive lymphocytes were transfected with the human NKT cell-derived TCRα and β chain mRNA (the Vα24 and Vβ11 TCR chains). When primary T cells transfected with NKT cell-derived TCR were subsequently stimulated with the NKT ligand, α-galactosylceramide (α-GalCer), they secreted IFN-γ in a ligand-specific manner. Furthermore when γδT cells were transfected with NKT cell-derived TCR mRNA, they demonstrated enhanced proliferation, IFN-γ production and antitumor effects after α-GalCer stimulation as compared to parental γδT cells. Importantly, NKT cell TCR-transfected γδT cells responded to both NKT cell and γδT cell ligands, rendering them bi-potential innate lymphocytes. Because NKT cell receptors are unique and universal invariant receptors in humans, the TCR chains do not yield mispaired receptors with endogenous TCR α and β chains after the transfection. The transfection of NKT cell TCR has the potential to be a new approach to tumor immunotherapy in patients with various types of cancer.

  12. Increased CD8+ T cell response to Epstein-Barr virus lytic antigens in the active phase of multiple sclerosis.

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    Daniela F Angelini

    Full Text Available It has long been known that multiple sclerosis (MS is associated with an increased Epstein-Barr virus (EBV seroprevalence and high immune reactivity to EBV and that infectious mononucleosis increases MS risk. This evidence led to postulate that EBV infection plays a role in MS etiopathogenesis, although the mechanisms are debated. This study was designed to assess the prevalence and magnitude of CD8+ T-cell responses to EBV latent (EBNA-3A, LMP-2A and lytic (BZLF-1, BMLF-1 antigens in relapsing-remitting MS patients (n = 113 and healthy donors (HD (n = 43 and to investigate whether the EBV-specific CD8+ T cell response correlates with disease activity, as defined by clinical evaluation and gadolinium-enhanced magnetic resonance imaging. Using HLA class I pentamers, lytic antigen-specific CD8+ T cell responses were detected in fewer untreated inactive MS patients than in active MS patients and HD while the frequency of CD8+ T cells specific for EBV lytic and latent antigens was higher in active and inactive MS patients, respectively. In contrast, the CD8+ T cell response to cytomegalovirus did not differ between HD and MS patients, irrespective of the disease phase. Marked differences in the prevalence of EBV-specific CD8+ T cell responses were observed in patients treated with interferon-β and natalizumab, two licensed drugs for relapsing-remitting MS. Longitudinal studies revealed expansion of CD8+ T cells specific for EBV lytic antigens during active disease in untreated MS patients but not in relapse-free, natalizumab-treated patients. Analysis of post-mortem MS brain samples showed expression of the EBV lytic protein BZLF-1 and interactions between cytotoxic CD8+ T cells and EBV lytically infected plasma cells in inflammatory white matter lesions and meninges. We therefore propose that inability to control EBV infection during inactive MS could set the stage for intracerebral viral reactivation and disease relapse.

  13. Modelling and Simulation of the Dynamics of the Antigen-Specific T Cell Response Using Variable Structure Control Theory.

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    Anet J N Anelone

    Full Text Available Experimental and mathematical studies in immunology have revealed that the dynamics of the programmed T cell response to vigorous infection can be conveniently modelled using a sigmoidal or a discontinuous immune response function. This paper hypothesizes strong synergies between this existing work and the dynamical behaviour of engineering systems with a variable structure control (VSC law. These findings motivate the interpretation of the immune system as a variable structure control system. It is shown that dynamical properties as well as conditions to analytically assess the transition from health to disease can be developed for the specific T cell response from the theory of variable structure control. In particular, it is shown that the robustness properties of the specific T cell response as observed in experiments can be explained analytically using a VSC perspective. Further, the predictive capacity of the VSC framework to determine the T cell help required to overcome chronic Lymphocytic Choriomeningitis Virus (LCMV infection is demonstrated. The findings demonstrate that studying the immune system using variable structure control theory provides a new framework for evaluating immunological dynamics and experimental observations. A modelling and simulation tool results with predictive capacity to determine how to modify the immune response to achieve healthy outcomes which may have application in drug development and vaccine design.

  14. Modelling and Simulation of the Dynamics of the Antigen-Specific T Cell Response Using Variable Structure Control Theory.

    Science.gov (United States)

    Anelone, Anet J N; Spurgeon, Sarah K

    2016-01-01

    Experimental and mathematical studies in immunology have revealed that the dynamics of the programmed T cell response to vigorous infection can be conveniently modelled using a sigmoidal or a discontinuous immune response function. This paper hypothesizes strong synergies between this existing work and the dynamical behaviour of engineering systems with a variable structure control (VSC) law. These findings motivate the interpretation of the immune system as a variable structure control system. It is shown that dynamical properties as well as conditions to analytically assess the transition from health to disease can be developed for the specific T cell response from the theory of variable structure control. In particular, it is shown that the robustness properties of the specific T cell response as observed in experiments can be explained analytically using a VSC perspective. Further, the predictive capacity of the VSC framework to determine the T cell help required to overcome chronic Lymphocytic Choriomeningitis Virus (LCMV) infection is demonstrated. The findings demonstrate that studying the immune system using variable structure control theory provides a new framework for evaluating immunological dynamics and experimental observations. A modelling and simulation tool results with predictive capacity to determine how to modify the immune response to achieve healthy outcomes which may have application in drug development and vaccine design.

  15. Modelling and Simulation of the Dynamics of the Antigen-Specific T Cell Response Using Variable Structure Control Theory

    Science.gov (United States)

    2016-01-01

    Experimental and mathematical studies in immunology have revealed that the dynamics of the programmed T cell response to vigorous infection can be conveniently modelled using a sigmoidal or a discontinuous immune response function. This paper hypothesizes strong synergies between this existing work and the dynamical behaviour of engineering systems with a variable structure control (VSC) law. These findings motivate the interpretation of the immune system as a variable structure control system. It is shown that dynamical properties as well as conditions to analytically assess the transition from health to disease can be developed for the specific T cell response from the theory of variable structure control. In particular, it is shown that the robustness properties of the specific T cell response as observed in experiments can be explained analytically using a VSC perspective. Further, the predictive capacity of the VSC framework to determine the T cell help required to overcome chronic Lymphocytic Choriomeningitis Virus (LCMV) infection is demonstrated. The findings demonstrate that studying the immune system using variable structure control theory provides a new framework for evaluating immunological dynamics and experimental observations. A modelling and simulation tool results with predictive capacity to determine how to modify the immune response to achieve healthy outcomes which may have application in drug development and vaccine design. PMID:27861537

  16. Follicular helper T cells poise immune responses to the development of autoimmune pathology.

    Science.gov (United States)

    Gómez-Martín, Diana; Díaz-Zamudio, Mariana; Romo-Tena, Jorge; Ibarra-Sánchez, María J; Alcocer-Varela, Jorge

    2011-04-01

    Follicular helper T cells (T(FH)) have been implicated as a lineage that provides sufficient help to B cells in order to become professional antibody producers. This T helper subset is characterized by a distinctive cell-surface phenotype (CD4(+)CD57(+)CXCR5(+)) and cytokine profile (IL-21, IL-6, and IL-27) as well as transcriptional program (BCL-6, ICOS, and PD-1). Evidence supports the concept that T(FH) subset development, as well as for other lineages, is dependent on microenvironment cues that modulate a particular transcriptional program, susceptible to plasticity. Recently, it has been shown that BCL-6 and IL-21 act as master regulators for the development and function of T(FH) cells. Moreover, costimulation via ICOS, as well as signaling proteins such as SAP constitute required elements of the regulatory network that modulates T(FH) functions. T(FH) dysregulation has been implicated in the development of autoimmune pathology, such as SLE. Indeed, the Sanroque mice associated to the mutation of Roquin, a ubiquitin ligase, essential for the regulation of ICOS and germinal center responses, constitutes a model that shares features with human SLE. Recently, the expansion of "circulating T(FH) cells" (CD4(+)CXCR5(+)ICOS(high)PD1(high)) has been described for a subset of SLE patients that share T(FH) dependent features of disease with Sanroque mice, such as glomerulonephritis and cytopenias. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Profiling the Targets of Protective CD8+ T Cell Responses to Infection

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    Joseph T. Bruder

    2017-12-01

    Full Text Available T cells are critical effectors of host immunity that target intracellular pathogens, such as the causative agents of HIV, tuberculosis, and malaria. The development of vaccines that induce effective cell-mediated immunity against such pathogens has proved challenging; for tuberculosis and malaria, many of the antigens targeted by protective T cells are not known. Here, we report a novel approach for screening large numbers of antigens as potential targets of T cells. Malaria provides an excellent model to test this antigen discovery platform because T cells are critical mediators of protection following immunization with live sporozoite vaccines and the specific antigen targets are unknown. We generated an adenovirus array by cloning 312 highly expressed pre-erythrocytic Plasmodium yoelii antigens into adenovirus vectors using high-throughput methodologies. The array was screened to identify antigen-specific CD8+ T cells induced by a live sporozoite vaccine regimen known to provide high levels of sterile protection mediated by CD8+ T cells. We identified 69 antigens that were targeted by CD8+ T cells induced by this vaccine regimen. The antigen that recalled the highest frequency of CD8+ T cells, PY02605, induced protective responses in mice, demonstrating proof of principle for this approach in identifying antigens for vaccine development.

  18. Local and Systemic CD4+ T Cell Exhaustion Reverses with Clinical Resolution of Pulmonary Sarcoidosis

    Directory of Open Access Journals (Sweden)

    Charlene Hawkins

    2017-01-01

    Full Text Available Investigation of the Th1 immune response in sarcoidosis CD4+ T cells has revealed reduced proliferative capacity and cytokine expression upon TCR stimulation. In other disease models, such cellular dysfunction has been associated with a step-wise, progressive loss of T cell function that results from chronic antigenic stimulation. T cell exhaustion is defined by decreased cytokine production upon TCR activation, decreased proliferation, increased expression of inhibitory cell surface receptors, and increased susceptibility to apoptosis. We characterized sarcoidosis CD4+ T cell immune function in systemic and local environments among subjects undergoing disease progression compared to those experiencing disease resolution. Spontaneous and TCR-stimulated Th1 cytokine expression and proliferation assays were performed in 53 sarcoidosis subjects and 30 healthy controls. PD-1 expression and apoptosis were assessed by flow cytometry. Compared to healthy controls, sarcoidosis CD4+ T cells demonstrated reductions in Th1 cytokine expression, proliferative capacity (p<0.05, enhanced apoptosis (p<0.01, and increased PD-1 expression (p<0.001. BAL-derived CD4+ T cells also demonstrated multiple facets of T cell exhaustion (p<0.05. Reversal of CD4+ T cell exhaustion was observed in subjects undergoing spontaneous resolution (p<0.05. Sarcoidosis CD4+ T cells exhibit loss of cellular function during progressive disease that follows the archetype of T cell exhaustion.

  19. NY-ESO-1- and survivin-specific T-cell responses in the peripheral blood from patients with glioma.

    Science.gov (United States)

    Liu, Zhenjiang; Poiret, Thomas; Persson, Oscar; Meng, Qingda; Rane, Lalit; Bartek, Jiri; Karbach, Julia; Altmannsberger, Hans-Michael; Illies, Christopher; Luo, Xiaohua; Harvey-Peredo, Inti; Jäger, Elke; Dodoo, Ernest; Maeurer, Markus

    2018-02-01

    The prognosis for patients with glioblastoma is grim. Ex vivo expanded tumor-associated antigen (TAA)-reactive T-cells from patients with glioma may represent a viable source for anticancer-directed cellular therapies. Immunohistochemistry was used to test the survivin (n = 40 samples) and NY-ESO-1 (n = 38 samples) protein expression in tumor specimens. T-cells from peripheral blood were stimulated with TAAs (synthetic peptides) in IL-2 and IL-7, or using a combination of IL-2, IL-15 and IL-21. CD4 + and CD8 + T-cells were tested for antigen-specific proliferation by flow cytometry, and IFN-γ production was tested by ELISA. Twenty-eight out of 38 cancer specimens exhibited NY-ESO-1 protein expression, 2/38 showed a strong universal (4+) NY-ESO-1 staining, and 9/40 cancer lesions exhibited a strong (4+) staining for survivin. We could detect antigen-specific IFN-γ responses in 25% blood samples for NY-ESO-1 and 30% for survivin. NY-ESO-1-expanded T-cells recognized naturally processed and presented epitopes. NY-ESO-1 or survivin expression in glioma represents viable targets for anticancer-directed T-cells for the biological therapy of patients with glioma.

  20. Semiallogenic fusions of MSI+ tumor cells and activated B cells induce MSI-specific T cell responses

    Directory of Open Access Journals (Sweden)

    Klier Ulrike

    2011-09-01

    Full Text Available Abstract Background Various strategies have been developed to transfer tumor-specific antigens into antigen presenting cells in order to induce cytotoxic T cell responses against tumor cells. One approach uses cellular vaccines based on fusions of autologous antigen presenting cells and allogeneic tumor cells. The fusion cells combine antigenicity of the tumor cell with optimal immunostimulatory capacity of the antigen presenting cells. Microsatellite instability caused by mutational inactivation of DNA mismatch repair genes results in translational frameshifts when affecting coding regions. It has been shown by us and others that these mutant proteins lead to the presentation of immunogenic frameshift peptides that are - in principle - recognized by a multiplicity of effector T cells. Methods We chose microsatellite instability-induced frameshift antigens as ideal to test for induction of tumor specific T cell responses by semiallogenic fusions of microsatellite instable carcinoma cells with CD40-activated B cells. Two fusion clones of HCT116 with activated B cells were selected for stimulation of T cells autologous to the B cell fusion partner. Outgrowing T cells were phenotyped and tested in functional assays. Results The fusion clones expressed frameshift antigens as well as high amounts of MHC and costimulatory molecules. Autologous T cells stimulated with these fusions were predominantly CD4+, activated, and reacted specifically against the fusion clones and also against the tumor cell fusion partner. Interestingly, a response toward 6 frameshift-derived peptides (of 14 tested could be observed. Conclusion Cellular fusions of MSI+ carcinoma cells and activated B cells combine the antigen-presenting capacity of the B cell with the antigenic repertoire of the carcinoma cell. They present frameshift-derived peptides and can induce specific and fully functional T cells recognizing not only fusion cells but also the carcinoma cells. These

  1. Chemokine Expression in Retinal Pigment Epithelial ARPE-19 Cells in Response to Coculture with Activated T Cells

    DEFF Research Database (Denmark)

    Juel, Helene Bæk; Faber, Carsten; Udsen, Maja

    2012-01-01

    -cell–derived cytokines by upregulating expression of multiple chemokines related to microglial, T-cell, and monocyte chemotaxis and activation. This inflammatory stress response may have implications for immune homeostasis in the retina, and for the further understanding of inflammatory ocular diseases such as uveitis......Purpose. To investigate the effects of T-cell–derived cytokines on gene and protein expression of chemokines in a human RPE cell line (ARPE-19). Methods. We used an in vitro coculture system in which the RPE and CD3/CD28–activated T-cells were separated by a membrane. RPE cell expression...

  2. Dichotomy in the human CD4+ T-cell response to Leishmania parasites

    DEFF Research Database (Denmark)

    Kemp, M; Kurtzhals, J A; Kharazmi, A

    1994-01-01

    Leishmania parasites cause human diseases ranging from self-healing cutaneous ulcers to fatal systemic infections. In addition, many individuals become infected without developing disease. In mice the two subsets of CD4+ T cells, Th1 and Th2, have different effects on the outcome of experimental...... Leishmania infections. Th1 cells producing interferon-gamma (IFN-gamma) mediate resistance, whereas Th2 cells producing interleukin-4 (IL-4) and IL-10 are associated with susceptibility and exacerbation. Evidence is accumulating that a Th1/Th2 dichotomy in the T-cell response to Leishmania exists also...

  3. Semiallogenic fusions of MSI+ tumor cells and activated B cells induce MSI-specific T cell responses

    International Nuclear Information System (INIS)

    Garbe, Yvette; Klier, Ulrike; Linnebacher, Michael

    2011-01-01

    Various strategies have been developed to transfer tumor-specific antigens into antigen presenting cells in order to induce cytotoxic T cell responses against tumor cells. One approach uses cellular vaccines based on fusions of autologous antigen presenting cells and allogeneic tumor cells. The fusion cells combine antigenicity of the tumor cell with optimal immunostimulatory capacity of the antigen presenting cells. Microsatellite instability caused by mutational inactivation of DNA mismatch repair genes results in translational frameshifts when affecting coding regions. It has been shown by us and others that these mutant proteins lead to the presentation of immunogenic frameshift peptides that are - in principle - recognized by a multiplicity of effector T cells. We chose microsatellite instability-induced frameshift antigens as ideal to test for induction of tumor specific T cell responses by semiallogenic fusions of microsatellite instable carcinoma cells with CD40-activated B cells. Two fusion clones of HCT116 with activated B cells were selected for stimulation of T cells autologous to the B cell fusion partner. Outgrowing T cells were phenotyped and tested in functional assays. The fusion clones expressed frameshift antigens as well as high amounts of MHC and costimulatory molecules. Autologous T cells stimulated with these fusions were predominantly CD4 + , activated, and reacted specifically against the fusion clones and also against the tumor cell fusion partner. Interestingly, a response toward 6 frameshift-derived peptides (of 14 tested) could be observed. Cellular fusions of MSI + carcinoma cells and activated B cells combine the antigen-presenting capacity of the B cell with the antigenic repertoire of the carcinoma cell. They present frameshift-derived peptides and can induce specific and fully functional T cells recognizing not only fusion cells but also the carcinoma cells. These hybrid cells may have great potential for cellular immunotherapy and

  4. T-cell responses before and after the fifth consecutive acellular pertussis vaccination in 4-year-old Dutch children.

    Science.gov (United States)

    Schure, Rose-Minke; Hendrikx, Lotte H; de Rond, Lia G H; Oztürk, Kemal; Sanders, Elisabeth A M; Berbers, Guy A M; Buisman, Anne-Marie

    2012-11-01

    Immunization with acellular pertussis vaccine (aP) induces higher specific antibody levels and fewer adverse reactions than does immunization with the whole-cell vaccine (wP). However, antibody levels in infants induced by both types of pertussis vaccines wane already after 1 year. Therefore, long-term T-cell responses upon vaccination might play a role in protection against pertussis. In a cross-sectional study (ISRCTN65428640), we investigated T-helper (Th) cell immune responses in wP- or aP-vaccinated children before and after an aP low-dose or high-dose preschool booster at 4 years of age in The Netherlands. T cells were stimulated with pertussis vaccine antigens. The numbers of gamma interferon-producing cells and Th1, Th2, Th17, and interleukin-10 (IL-10) cytokine concentrations were determined. In addition, pertussis-specific IgE levels were measured in plasma. Children being vaccinated with aP vaccinations at 2, 3, 4, and 11 months of age still showed higher pertussis-specific T-cell responses at 4 years of age than did wP-vaccinated children. These T-cell responses failed to show a typical increase in cytokine production after a fifth aP vaccination but remained high after a low-dose booster and seemed to decline even after a high-dose booster. Importantly, elevated IgE levels were induced after this booster vaccination. In contrast, wP-vaccinated children had only low prebooster T-cell responses, and these children showed a clear postbooster T-cell memory response even after a low-dose booster vaccine. Four high-dose aP vaccinations in infancy induce high T-cell responses still present even 3 years after vaccination and enhanced IgE responses after preschool booster vaccination. Therefore, studies of changes in vaccine dosage, timing of pertussis (booster) vaccinations, and the possible association with local side effects are necessary.

  5. Differential immunodominance hierarchy of CD8+ T-cell responses in HLA-B*27

    DEFF Research Database (Denmark)

    Adland, Emily; Hill, Matilda; Lavandier, Nora

    2018-01-01

    The well-characterized association between HLA-B*27:05 and protection against HIV disease progression has been linked to immunodominant HLA-B*27:05- restricted CD8+ T-cell responses toward the conserved Gag KK10 (residues 263 to 272) and polymerase (Pol) KY9 (residues 901 to 909) epitopes. We stu...

  6. Heat shock protein gp96 adjuvant induces T cell responses and cross-protection to a split influenza vaccine.

    Science.gov (United States)

    Ju, Ying; Fan, Hongxia; Liu, Jun; Hu, Jun; Li, Xinghui; Li, Changfei; Chen, Lizhao; Gao, Qiang; Gao, George F; Meng, Songdong

    2014-05-13

    The commonly used inactivated or split influenza vaccines induce only induce minimal T cell responses and are less effective in preventing heterologous virus infection. Thus, developing cross-protective influenza vaccines against the spread of a new influenza virus is an important strategy against pandemic emergence. Here we demonstrated that immunization with heat shock protein gp96 as adjuvant led to a dramatic increased antigen-specific T cell response to a pandemic H1N1 split vaccine. Notably, gp96 elicited a cross-protective CD8(+) T cell response to the internal conserved viral protein NP. Although the split pH1N1vaccine alone has low cross-protective efficiency, adding gp96 as an adjuvant effectively improved the cross-protection against challenge with a heterologous virus in mice. Our study reveals the novel property of gp96 in boosting the T cell response against conserved epitopes of influenza virus and its potential use as an adjuvant for human pre-pandemic inactivated influenza vaccines against different viral subtypes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Redundancy of direct priming and cross-priming in tumor-specific CD8(+) T cell responses

    NARCIS (Netherlands)

    Wolkers, M. C.; Stoetter, G.; Vyth-Dreese, F. A.; Schumacher, T. N.

    2001-01-01

    Against a subset of human cancers, vigorous tumor-specific CD8(+) T cell responses can develop either spontaneously or upon allogeneic transplantation. However, the parameters that determine the induction of such pronounced anti-tumor immunity remain ill defined. To dissect the conditions required

  8. Sterilizing immunity to influenza virus infection requires local antigen-specific T cell response in the lungs.

    Science.gov (United States)

    Dutta, Avijit; Huang, Ching-Tai; Lin, Chun-Yen; Chen, Tse-Ching; Lin, Yung-Chang; Chang, Chia-Shiang; He, Yueh-Chia

    2016-09-06

    Sterilizing immunity is a unique immune status, which prevents effective virus infection into the host. It is different from the immunity that allows infection but with subsequent successful eradication of the virus. Pre-infection induces sterilizing immunity to homologous influenza virus challenge in ferret. In our antigen-specific experimental system, mice pre-infected with PR8 influenza virus through nasal route are likewise resistant to reinfection of the same strain of virus. The virus is cleared before establishment of effective infection. Intramuscular influenza virus injection confers protection against re-infection with facilitated virus clearance but not sterilizing immunity. Pre-infection and intramuscular injection generates comparable innate immunity and antibody response, but only pre-infection induces virus receptor reduction and efficient antigen-specific T cell response in the lungs. Pre-infection with nH1N1 influenza virus induces virus receptor reduction but not PR8-specific T cell immune response in the lungs and cannot prevent infection of PR8 influenza virus. Pre-infection with PR8 virus induced PR8-specific T cell response in the lungs but cannot prevent infection of nH1N1 virus either. These results reveal that antigen-specific T cell immunity is required for sterilizing immunity.

  9. Complement modulation of T cell immune responses during homeostasis and disease.

    Science.gov (United States)

    Clarke, Elizabeth V; Tenner, Andrea J

    2014-11-01

    The complement system is an ancient and critical effector mechanism of the innate immune system as it senses, kills, and clears infectious and/or dangerous particles and alerts the immune system to the presence of the infection and/or danger. Interestingly, an increasing number of reports have demonstrated a clear role for complement in the adaptive immune system as well. Of note, a number of recent studies have identified previously unknown roles for complement proteins, receptors, and regulators in T cell function. Here, we will review recent data demonstrating the influence of complement proteins C1q, C3b/iC3b, C3a (and C3aR), and C5a (and C5aR) and complement regulators DAF (CD55) and CD46 (MCP) on T cell function during homeostasis and disease. Although new concepts are beginning to emerge in the field of complement regulation of T cell function, future experiments should focus on whether complement is interacting directly with the T cell or is having an indirect effect on T cell function via APCs, the cytokine milieu, or downstream complement activation products. Importantly, the identification of the pivotal molecular pathways in the human systems will be beneficial in the translation of concepts derived from model systems to therapeutic targeting for treatment of human disorders. © 2014 Society for Leukocyte Biology.

  10. Polymorphisms in Protein Tyrosine Phosphatase Non-receptor Type 2 and 22 (PTPN2/22 Are Linked to Hyper-Proliferative T-Cells and Susceptibility to Mycobacteria in Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Robert C. Sharp

    2018-01-01

    Full Text Available A shared genetic pre-disposition, chronic inflammation, and treatment with similar biologics between Rheumatoid arthritis (RA and Crohn's disease (CD have intrigued us to investigate whether the two disorders share trigger association or possible causation. We hypothesized earlier that Single Nucleotide Polymorphisms (SNPs in the negative regulators Protein Tyrosine Phosphatase Non-receptor type 2 and 22 (PTPN2/22 lead to a dysregulated immune response, susceptibility to environmental triggers, and continued apoptosis as seen in chronic inflammation in RA and CD. To test the hypothesis, peripheral leukocytes samples from 132 consented subjects were genotyped for 9 SNPs in PTPN2/22 using TaqMan™ genotyping. The effect of the SNPs on PTPN2/22 and IFN-γ expression was determined using real time PCR. T-cell proliferation and response to phytohematoagglutonin (PHA mitogen and mycobacterial antigens were determined by BrdU proliferation assay. Blood samples were also analyzed for the Mycobacterium avium subspecies paratuberculosis (MAP IS900 gene by nPCR. Out of 9 SNPs examined, heterozygous (TC or minor (CC alleles of PTPN2:rs478582 occurred in 79% RA compared to 60% healthy controls (p-values ≤ 0.05; OR = 2.28. Similarly, heterozygous (GA or minor (AA alleles of PTPN22:rs2476601 occurred in 29% RA compared to 6% healthy controls (p-values ≤ 0.05; OR = 5.90. PTPN2/22 expression in RA was decreased by 1.2-fold compared to healthy controls. PTPN2:rs478582 upregulated IFN-γ in RA by 1.5-fold. Combined PTPN2:rs478582 and PTPN22:rs2476601 increased T-cell proliferation by 2.7-fold when treated with PHA. Surprisingly, MAP DNA was detected in 34% of RA samples compared to 8% healthy controls, (p-values ≤ 0.05, OR = 5.74. RA samples with PTPN2:rs478582 and/or PTPN22:rs2476601 were more positive for MAP than samples without polymorphisms. Combined occurrence of PTPN2:rs478582 and PTPN22:rs2476601 in association with the presence of MAP has

  11. Quantitative analysis of the acute and long-term CD4(+) T-cell response to a persistent gammaherpesvirus

    DEFF Research Database (Denmark)

    Christensen, Jan Pravsgaard; Doherty, P C

    1999-01-01

    in the mediastinal lymph nodes and then in the cervical lymph nodes and the spleen. The numbers of MHV-68-specific CD4(+) T cells generated in congenic mice homozygous for disruption of the beta2-microglobulin gene tended to be higher, indicating that the absence of the CD8(+) set in this group resulted......The murine gammaherpesvirus 68 (MHV-68) replicates in respiratory epithelial cells, where it establishes a persistent, latent infection limited predominantly to B lymphocytes. The virus-specific CD4(+) T-cell response in C57BL/6 mice challenged intranasally with MHV-68 is detected first...... in a compensatory response. The peak frequency within the splenic CD4(+) T-cell population may reach 1:50 in the acute response; it then drops to 1:400 to 1:500 within 4 months and stays at that level in the very long term. Sorting for L-selectin (CD62L) expression established that all virus-specific CD4(+) T cells...

  12. Enhanced cross-presentation and improved CD8+ T cell responses after mannosylation of synthetic long peptides in mice.

    Science.gov (United States)

    Rauen, Judith; Kreer, Christoph; Paillard, Arlette; van Duikeren, Suzanne; Benckhuijsen, Willemien E; Camps, Marcel G; Valentijn, A Rob P M; Ossendorp, Ferry; Drijfhout, Jan W; Arens, Ramon; Burgdorf, Sven

    2014-01-01

    The use of synthetic long peptides (SLP) has been proven to be a promising approach to induce adaptive immune responses in vaccination strategies. Here, we analyzed whether the efficiency to activate cytotoxic T cells by SLP-based vaccinations can be increased by conjugating SLPs to mannose residues. We could demonstrate that mannosylation of SLPs results in increased internalization by the mannose receptor (MR) on murine antigen-presenting cells. MR-mediated internalization targeted the mannosylated SLPs into early endosomes, from where they were cross-presented very efficiently compared to non-mannosylated SLPs. The influence of SLP mannosylation was specific for cross-presentation, as no influence on MHC II-restricted presentation was observed. Additionally, we showed that vaccination of mice with mannosylated SLPs containing epitopes from either ovalbumin or HPV E7 resulted in enhanced proliferation and activation of antigen-specific CD8+ T cells. These findings demonstrate that mannosylation of SLPs augments the induction of a cytotoxic T cell response in vitro and in vivo and might be a promising approach to induce cytotoxic T cell responses in e.g. cancer therapy and anti-viral immunity.

  13. Archaeosome Adjuvant Overcomes Tolerance to Tumor-Associated Melanoma Antigens Inducing Protective CD8+ T Cell Responses

    Directory of Open Access Journals (Sweden)

    Lakshmi Krishnan

    2010-01-01

    Full Text Available Vesicles comprised of the ether glycerolipids of the archaeon Methanobrevibacter smithii (archaeosomes are potent adjuvants for evoking CD8+ T cell responses. We therefore explored the ability of archaeosomes to overcome immunologic tolerance to self-antigens. Priming and boosting of mice with archaeosome-antigen evoked comparable CD8+ T cell response and tumor protection to an alternate boosting strategy utilizing live bacterial vectors for antigen delivery. Vaccination with melanoma antigenic peptides TRP181-189 and Gp10025-33 delivered in archaeosomes resulted in IFN-γ producing antigen-specific CD8+ T cells with strong cytolytic capability and protection against subcutaneous B16 melanoma. Targeting responses against multiple antigens afforded prolonged median survival against melanoma challenge. Entrapment of multiple peptides within the same vesicle or admixed formulations were both effective at evoking CD8+ T cells against each antigen. Melanoma-antigen archaeosome formulations also afforded therapeutic protection against established B16 tumors when combined with depletion of T-regulatory cells. Overall, we demonstrate that archaeosome adjuvants constitute an effective choice for formulating cancer vaccines.

  14. Local suppression of T cell responses by arginase-induced L-arginine depletion in nonhealing leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Manuel Modolell

    2009-07-01

    Full Text Available The balance between T helper (Th 1 and Th2 cell responses is a major determinant of the outcome of experimental leishmaniasis, but polarized Th1 or Th2 responses are not sufficient to account for healing or nonhealing. Here we show that high arginase activity, a hallmark of nonhealing disease, is primarily expressed locally at the site of pathology. The high arginase activity causes local depletion of L-arginine, which impairs the capacity of T cells in the lesion to proliferate and to produce interferon-gamma, while T cells in the local draining lymph nodes respond normally. Healing, induced by chemotherapy, resulted in control of arginase activity and reversal of local immunosuppression. Moreover, competitive inhibition of arginase as well as supplementation with L-arginine restored T cell effector functions and reduced pathology and parasite growth at the site of lesions. These results demonstrate that in nonhealing leishmaniasis, arginase-induced L-arginine depletion results in impaired T cell responses. Our results identify a novel mechanism in leishmaniasis that contributes to the failure to heal persistent lesions and suggest new approaches to therapy.

  15. Inhibition of viral replication reduces regulatory T cells and enhances the antiviral immune response in chronic hepatitis B.

    Science.gov (United States)

    Stoop, Jeroen N; van der Molen, Renate G; Kuipers, Ernst J; Kusters, Johannes G; Janssen, Harry L A

    2007-04-25

    Regulatory T cells (Treg) play a key role in the impaired immune response that is typical for a chronic Hepatitis B virus (HBV) infection. To gain more insight in the mechanism that is responsible for this impaired immune response, the effect of viral load reduction resulting from treatment with the nucleotide analogue adefovir dipivoxil on the percentages of Treg and HBV-specific T-cell responses was analyzed. Peripheral blood mononuclear cells (PBMC) of 12 patients were collected at baseline and during treatment. In parallel to the decline in viral load, we found a decline in circulating Treg, combined with an increase in HBV core antigen-specific IFN-gamma production and proliferation. The production of IL10 did not decrease during therapy. In conclusion, adefovir induced viral load reduction results in a decline of circulating Treg together with a partial recovery of the immune response.

  16. Inhibition of viral replication reduces regulatory T cells and enhances the antiviral immune response in chronic hepatitis B

    International Nuclear Information System (INIS)

    Stoop, Jeroen N.; Molen, Renate G. van der; Kuipers, Ernst J.; Kusters, Johannes G.; Janssen, Harry L.A.

    2007-01-01

    Regulatory T cells (Treg) play a key role in the impaired immune response that is typical for a chronic Hepatitis B virus (HBV) infection. To gain more insight in the mechanism that is responsible for this impaired immune response, the effect of viral load reduction resulting from treatment with the nucleotide analogue adefovir dipivoxil on the percentages of Treg and HBV-specific T-cell responses was analyzed. Peripheral blood mononuclear cells (PBMC) of 12 patients were collected at baseline and during treatment. In parallel to the decline in viral load, we found a decline in circulating Treg, combined with an increase in HBV core antigen-specific IFN-γ production and proliferation. The production of IL10 did not decrease during therapy. In conclusion, adefovir induced viral load reduction results in a decline of circulating Treg together with a partial recovery of the immune response

  17. Prevotella intermedia Stimulates Expansion of Vβ-Specific CD4+ T Cells

    Science.gov (United States)

    Leung, K.-P.; Torres, Barbara A.

    2000-01-01

    Recent evidence suggests that certain periodontal pathogens preferentially stimulate T cells expressing specific variable regions on the β chain (Vβ) of the T-cell receptor, which may indicate the presence of a superantigen. Superantigens are microbial proteins that activate large numbers of CD4+ T cells in a Vβ-specific manner. The purpose of this study was to determine whether Prevotella intermedia, a putative periodontal pathogen, activates populations of specific Vβ on CD4+ T cells. Among the bacterial strains tested, P. intermedia strain 17, a clinical isolate, induced the strongest proliferative response in peripheral blood mononuclear cells. Antibodies raised against whole cells of this organism blocked the proliferative activity. P. intermedia-induced proliferation was T-cell specific and required the presence of antigen-presenting cells. Flow cytometric analysis showed that CD4+ T-cell subsets expressing Vβ8, Vβ12, and Vβ17 expanded in response to P. intermedia strain 17. The ability of P. intermedia to stimulate CD4+-T-cell proliferation was further supported by the production profiles of key T-cell cytokines, gamma interferon and interleukin-2. The data collectively suggest that certain strains of P. intermedia can activate Vβ-specific T cells in a manner similar to that of other known microbial superantigens. PMID:10948175

  18. Regulatory B and T cell responses in patients with autoimmune thyroid disease and healthy controls

    DEFF Research Database (Denmark)

    Kristensen, Birte

    2016-01-01

    Autoimmune diseases occur due to faulty self-tolerance. Graves' disease (GD) and Hashimoto's thyroiditis (HT) are classic examples of organ-specific autoimmune diseases. GD is an auto-antibody-mediated disease where autoantibodies are produced against the thyroid stimulating hormone receptor (TSHR......). HT is primarily a T-cell mediated disease, and whether B cells play a pathogenic role in the pathogenesis is still unclear. Both GD and HT are characterized by infiltration of the thyroid gland by self-reactive T cells and B cells. In the first paper of this thesis, the role of regulatory B cells...... (Bregs) and regulatory T cells (Tregs) were investigated in the context of GD and HT. First, we studied the role of the thyroid self-antigen, thyroglobulin (TG) in healthy donors. The self-antigen TG, but not the foreign recall antigen tetanus toxoid (TT), was able to induce interleukin 10 (IL-10...

  19. T-cell autophagy deficiency increases mortality and suppresses immune responses after sepsis.

    Directory of Open Access Journals (Sweden)

    Chih-Wen Lin

    Full Text Available Although the role of autophagy in sepsis has been characterized in several organs, its role in the adaptive immune system remains to be ascertained. This study aimed to investigate the role of autophagy in sepsis-induced T cell apoptosis and immunosuppression, using knockout mice with T cell specific deletion of autophagy essential gene Atg7.Sepsis was induced in a cecal ligation and puncture (CLP model, with T-cell-specific Atg7-knockout mice compared to control mice. Autophagic vacuoles examined by electron microscopy were decreased in the spleen after CLP. Autophagy proteins LC3-II and ATG7, and autophagosomes and autolysosomes stained by Cyto-ID Green and acridine orange were decreased in CD4+ and CD8+ splenocytes at 18 h and 24 h after CLP. This decrease in autophagy was associated with increased apoptosis of CD4+ and CD8+ after CLP. Moreover, mice lacking Atg7 in T lymphocytes showed an increase in sepsis-induced mortality, T cell apoptosis and loss of CD4+ and CD8+ T cells, in comparison to control mice. This was accompanied by suppressed cytokine production of Th1/Th2/Th17 by CD4+ T cells, reduced phagocytosis in macrophages and decreased bacterial clearance in the spleen after sepsis.These results indicated that sepsis led to down-regulation of autophagy in T lymphocytes, which may result in enhanced apoptosis induction and decreased survival in sepsis. Autophagy may therefore play a protective role against sepsis-induced T lymphocyte apoptosis and immunosuppression.

  20. Interferon-γ Prevents Death of Bystander Neurons during CD8 T Cell Responses in the Brain

    Science.gov (United States)

    Richter, Kirsten; Hausmann, Jürgen; Staeheli, Peter

    2009-01-01

    T cells restricted to neurotropic viruses are potentially harmful as their activity may result in the destruction of neurons. In the Borna disease virus (BDV) model, antiviral CD8 T cells entering the brain of infected mice cause neurological disease but no substantial loss of neurons unless the animals lack interferon-γ (IFN-γ). We show here that glutamate receptor antagonists failed to prevent BDV-induced neuronal loss in IFN-γ-deficient mice, suggesting that excitotoxicity resulting from glutamate receptor overstimulation is an unlikely explanation for the neuronal damage. Experiments with IFN-γ-deficient mice lacking eosinophils indicated that these cells, which specifically accumulate in the infected brains of IFN-γ-deficient mice, are not responsible for CA1 neuronal death. Interestingly, BDV-induced damage of CA1 neurons was reduced significantly in IFN-γ-deficient mice lacking perforin, suggesting a key role for CD8 T cells in this pathological process. Specific death of hippocampal CA1 neurons could be triggered by adoptive transfer of BDV-specific CD8 T cells from IFN-γ-deficient mice into uninfected mice that express transgene-encoded BDV antigen at high level in astrocytes. These results indicate that attack by CD8 T cells that cause the death of CA1 neurons might be directed toward regional astrocytes and that IFN-γ protects vulnerable CA1 neurons from collateral damage resulting from exposure to potentially toxic substances generated as a result of CD8 T cell-mediated impairment of astrocyte function. PMID:19359516

  1. Mechanisms of cyclic nucleotide phosphodiesterases in modulating T cell responses in murine graft-versus-host disease.

    Directory of Open Access Journals (Sweden)

    Michael Weber

    Full Text Available Graft-versus-host disease (GvHD is a key contributor to the morbidity and mortality after allogeneic hematopoetic stem cell transplantation (HSCT. Regulatory Foxp3(+ CD4(+ T cells (Treg suppress conventional T cell activation and can control GvHD. In our previous work, we demonstrate that a basic mechanism of Treg mediated suppression occurs by the transfer of cyclic adenosine monophosphate (cAMP to responder cells. Whether this mechanism is relevant for Treg mediated suppression of GvHD is currently unknown. To address this question, bone marrow and T cells from C57BL/6 mice were transferred into lethally irradiated BALB/c recipients, and the course of GvHD and survival were monitored. Transplanted recipients developed severe GvHD that was strongly ameliorated by the transfer of donor Treg cells. Towards the underlying mechanisms, in vitro studies revealed that Treg communicated with DCs via gap junctions, resulting in functional inactivation of DC by a metabolic pathway involving cAMP that is modulated by the phosphodiesterase (PDE 4 inhibitor rolipram. PDE2 or PDE3 inhibitors as well as rolipram suppressed allogeneic T cell activation, indirectly by enhancing Treg mediated suppression of DC activation and directly by inhibiting responder T cell proliferation. In line with this, we observed a cooperative suppression of GvHD upon Treg transfer and additional rolipram treatment. In conclusion, we propose that an important pathway of Treg mediated control of GvHD is based on a cAMP dependent mechanism. These data provide the basis for future concepts to manipulate allogeneic T cell responses to prevent GvHD.

  2. Soluble common gamma chain exacerbates COPD progress through the regulation of inflammatory T cell response in mice

    Directory of Open Access Journals (Sweden)

    Lee B

    2017-03-01

    Full Text Available Byunghyuk Lee,1 Eunhee Ko,1 Jiyeon Lee,2 Yuna Jo,1 Hyunju Hwang,1 Tae Sik Goh,1,3 Myungsoo Joo,2 Changwan Hong1 1Department of Anatomy and Cell Biology, Pusan National University School of Medicine, 2Division of Applied Medicine, School of Korean Medicine, Pusan National University, Yangsan, 3Department of Orthopedic Surgery, Medical Research Institute, Pusan National University School of Medicine, Busan, South Korea Abstract: Cigarette smoking (CS is a major cause of considerable morbidity and mortality by inducing lung cancer and COPD. COPD, a smoking-related disorder, is closely related to the alteration of immune system and inflammatory processes that are specifically mediated by T cells. Soluble common gamma chain (sγc has recently been identified as a critical regulator of the development and differentiation of T cells. We examined the effects of sγc in a cigarette smoke extract (CSE mouse model. The sγc level in CSE mice serum is significantly downregulated, and the cellularity of lymph node (LN is systemically reduced in the CSE group. Overexpression of sγc enhances the cellularity and IFNγ production of CD8 T cells in LN and also enhances Th1 and Th17 differentiation of CD4 T cells in the respiratory tract. Mechanistically, the downregulation of sγc expression mediated by CSE is required to prevent excessive inflammatory T cell responses. Therefore, our data suggest that sγc may be one of the target molecules for the control of immunopathogenic progresses in COPD. Keywords: COPD, T cell, soluble common gamma chain, cytokine

  3. Mycobacterium leprae-Infected Macrophages Preferentially Primed Regulatory T Cell Responses and Was Associated with Lepromatous Leprosy.

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    Degang Yang

    2016-01-01

    Full Text Available The persistence of Mycobacterium leprae (M. leprae infection is largely dependent on the types of host immune responses being induced. Macrophage, a crucial modulator of innate and adaptive immune responses, could be directly infected by M. leprae. We therefore postulated that M. leprae-infected macrophages might have altered immune functions.Here, we treated monocyte-derived macrophages with live or killed M. leprae, and examined their activation status and antigen presentation. We found that macrophages treated with live M. leprae showed committed M2-like function, with decreased interleukin 1 beta (IL-1beta, IL-6, tumor necrosis factor alpha (TNF-alpha and MHC class II molecule expression and elevated IL-10 and CD163 expression. When incubating with naive T cells, macrophages treated with live M. leprae preferentially primed regulatory T (Treg cell responses with elevated FoxP3 and IL-10 expression, while interferon gamma (IFN-gamma expression and CD8+ T cell cytotoxicity were reduced. Chromium release assay also found that live M. leprae-treated macrophages were more resistant to CD8+ T cell-mediated cytotoxicity than sonicated M. leprae-treated monocytes. Ex vivo studies showed that the phenotype and function of monocytes and macrophages had clear differences between L-lep and T-lep patients, consistent with the in vitro findings.Together, our data demonstrate that M. leprae could utilize infected macrophages by two mechanisms: firstly, M. leprae-infected macrophages preferentially primed Treg but not Th1 or cytotoxic T cell responses; secondly, M. leprae-infected macrophages were more effective at evading CD8+ T cell-mediated cytotoxicity.

  4. Ionizing radiation affects generation of MART-1-specific cytotoxic T cell responses by dendritic cells

    International Nuclear Information System (INIS)

    Liao, Y.P.; Wang, C.-C.; McBride, W.H.

    2003-01-01

    Full text: The human MART-1/Melan-A (MART-1) melanoma tumor antigen is known to be recognized by cytotoxic T lymphocytes (CTLs) and several groups are using this target for clinical immunotherapy. Most approaches use dendritic cells (DCs) that are potent antigen presentation cells for initiating CTL responses. In order for CTL recognition to occur, DCs must display 9-residue antigenic peptides on MHC class I molecules. These peptides are generated by proteasome degradation and then transported through the endoplasmic reticulum to the cell surface where they stabilize MHC class I expression. Our previous data showed that irradiation inhibits proteasome function and, therefore, we hypothesized that irradiation may inhibit antigen processing and CTL activation, as has been shown for proteasome inhibitors. To study the importance of irradiation effects on DCs, we studied the generation MART-1-specific CTL responses. Preliminary data showed that irradiation of murine bone marrow derived DCs did not affect expression of MHC class I, II, CD80, or CD86, as assessed by flow cytometric analyses 24-hour after irradiation. The effect of irradiation on MART-1 antigen processing by DCs was evaluated using DC transduced with adenovirus MART-1 (AdVMART1). C57BL/6 mice were immunized with AdVMART1 transduced DCs, with and without prior irradiation. IFN-γ production was measured by ELISPOT assays after 10-14 days of immunization. Prior radiation treatment resulted in a significant decrease in MART-1-specific T cell responses. The ability of irradiated and non-irradiated AdVMART1/DC vaccines to protect mice against growth of murine B16 tumors, which endogenously express murine MART-1, was also examined. AdVMART1/DC vaccination protected C57BL/6 mice against challenge with viable B16 melanoma cells while DCs irradiated (10 Gy) prior to AdVMART1 transduction abrogated protection. These results suggest that proteasome inhibition in DCs by irradiation may be a possible pathway in

  5. T Cell Response in Patients with Implanted Biological and Mechanical Prosthetic Heart Valves

    OpenAIRE

    Barbarash, L.; Kudryavtsev, I.; Rutkovskaya, N.; Golovkin, A.

    2016-01-01

    The study was aimed at assessing T cell subsets of peripheral blood from recipients of long-term functioning (more than 60 months) biological and mechanical heart valve prostheses. The absolute and relative number of CD4 and CD8 T cell subsets was analyzed: na?ve (N, CD45RA+CD62L+), central memory (CM, CD45RA?CD62L+), effector memory (EM, CD45RA?CD62L?), and terminally differentiated CD45RA-positive effector memory (TEMRA, CD45RA+CD62L?) in 25 persons with biological and 7 with mechanical pro...

  6. Nutritional imbalances and infections affect the thymus: consequences on T-cell-mediated immune responses.

    Science.gov (United States)

    Savino, Wilson; Dardenne, Mireille

    2010-11-01

    The thymus gland, where T lymphocyte development occurs, is targeted in malnutrition secondary to protein energy deficiency. There is a severe thymic atrophy, resulting from massive thymocyte apoptosis (particularly affecting the immature CD4+CD8+ cell subset) and decrease in cell proliferation. The thymic microenvironment (the non-lymphoid compartment that drives intrathymic T-cell development) is also affected in malnutrition: morphological changes in thymic epithelial cells were found, together with a decrease of thymic hormone production, as well as an increase of intrathymic contents of extracellular proteins. Profound changes in the thymus can also be seen in deficiencies of vitamins and trace elements. Taking Zn deficiency as an example, there is a substantial thymic atrophy. Importantly, marginal Zn deficiency in AIDS subjects, children with diarrhoea and elderly persons, significantly impairs the host's immunity, resulting in an increased risk of opportunistic infections and mortality; effects that are reversed by Zn supplementation. Thymic changes also occur in acute infectious diseases, including a severe thymic atrophy, mainly due to the depletion of CD4+CD8+ thymocytes, decrease in thymocyte proliferation, in parallel to densification of the epithelial network and increase in the extracellular matrix contents, with consequent disturbances in thymocyte migration and export. In conclusion, the thymus is targeted in several conditions of malnutrition as well as in acute infections. These changes are related to the impaired peripheral immune response seen in malnourished and infected individuals. Thus, strategies inducing thymus replenishment should be considered as adjuvant therapeutics to improve immunity in malnutrition and/or acute infectious diseases.

  7. T cells' immunological synapses induce polarization of brain astrocytes in vivo and in vitro: a novel astrocyte response mechanism to cellular injury.

    Science.gov (United States)

    Barcia, Carlos; Sanderson, Nicholas S R; Barrett, Robert J; Wawrowsky, Kolja; Kroeger, Kurt M; Puntel, Mariana; Liu, Chunyan; Castro, Maria G; Lowenstein, Pedro R

    2008-08-20

    Astrocytes usually respond to trauma, stroke, or neurodegeneration by undergoing cellular hypertrophy, yet, their response to a specific immune attack by T cells is poorly understood. Effector T cells establish specific contacts with target cells, known as immunological synapses, during clearance of virally infected cells from the brain. Immunological synapses mediate intercellular communication between T cells and target cells, both in vitro and in vivo. How target virally infected astrocytes respond to the formation of immunological synapses established by effector T cells is unknown. Herein we demonstrate that, as a consequence of T cell attack, infected astrocytes undergo dramatic morphological changes. From normally multipolar cells, they become unipolar, extending a major protrusion towards the immunological synapse formed by the effector T cells, and withdrawing most of their finer processes. Thus, target astrocytes become polarized towards the contacting T cells. The MTOC, the organizer of cell polarity, is localized to the base of the protrusion, and Golgi stacks are distributed throughout the protrusion, reaching distally towards the immunological synapse. Thus, rather than causing astrocyte hypertrophy, antiviral T cells cause a major structural reorganization of target virally infected astrocytes. Astrocyte polarization, as opposed to hypertrophy, in response to T cell attack may be due to T cells providing a very focused attack, and thus, astrocytes responding in a polarized manner. A similar polarization of Golgi stacks towards contacting T cells was also detected using an in vitro allogeneic model. Thus, different T cells are able to induce polarization of target astrocytes. Polarization of target astrocytes in response to immunological synapses may play an important role in regulating the outcome of the response of astrocytes to attacking effector T cells, whether during antiviral (e.g. infected during HIV, HTLV-1, HSV-1 or LCMV infection), anti

  8. T cells' immunological synapses induce polarization of brain astrocytes in vivo and in vitro: a novel astrocyte response mechanism to cellular injury.

    Directory of Open Access Journals (Sweden)

    Carlos Barcia

    2008-08-01

    Full Text Available Astrocytes usually respond to trauma, stroke, or neurodegeneration by undergoing cellular hypertrophy, yet, their response to a specific immune attack by T cells is poorly understood. Effector T cells establish specific contacts with target cells, known as immunological synapses, during clearance of virally infected cells from the brain. Immunological synapses mediate intercellular communication between T cells and target cells, both in vitro and in vivo. How target virally infected astrocytes respond to the formation of immunological synapses established by effector T cells is unknown.Herein we demonstrate that, as a consequence of T cell attack, infected astrocytes undergo dramatic morphological changes. From normally multipolar cells, they become unipolar, extending a major protrusion towards the immunological synapse formed by the effector T cells, and withdrawing most of their finer processes. Thus, target astrocytes become polarized towards the contacting T cells. The MTOC, the organizer of cell polarity, is localized to the base of the protrusion, and Golgi stacks are distributed throughout the protrusion, reaching distally towards the immunological synapse. Thus, rather than causing astrocyte hypertrophy, antiviral T cells cause a major structural reorganization of target virally infected astrocytes.Astrocyte polarization, as opposed to hypertrophy, in response to T cell attack may be due to T cells providing a very focused attack, and thus, astrocytes responding in a polarized manner. A similar polarization of Golgi stacks towards contacting T cells was also detected using an in vitro allogeneic model. Thus, different T cells are able to induce polarization of target astrocytes. Polarization of target astrocytes in response to immunological synapses may play an important role in regulating the outcome of the response of astrocytes to attacking effector T cells, whether during antiviral (e.g. infected during HIV, HTLV-1, HSV-1 or LCMV

  9. An unstable Th epitope of P. falciparum fosters central memory T cells and anti-CS antibody responses.

    Directory of Open Access Journals (Sweden)

    Carlos A Parra-López

    Full Text Available Malaria is transmitted by Plasmodium-infected anopheles mosquitoes. Widespread resistance of mosquitoes to insecticides and resistance of parasites to drugs highlight the urgent need for malaria vaccines. The most advanced malaria vaccines target sporozoites, the infective form of the parasite. A major target of the antibody response to sporozoites are the repeat epitopes of the circumsporozoite (CS protein, which span almost one half of the protein. Antibodies to these repeats can neutralize sporozoite infectivity. Generation of protective antibody responses to the CS protein (anti-CS Ab requires help by CD4 T cells. A CD4 T cell epitope from the CS protein designated T* was previously identified by screening T cells from volunteers immunized with irradiated P. falciparum sporozoites. The T* sequence spans twenty amino acids that contains multiple T cell epitopes restricted by various HLA alleles. Subunit malaria vaccines including T* are highly immunogenic in rodents, non-human primates and humans. In this study we characterized a highly conserved HLA-DRβ1*04:01 (DR4 restricted T cell epitope (QNT-5 located at the C-terminus of T*. We found that a peptide containing QNT-5 was able to elicit long-term anti-CS Ab responses and prime CD4 T cells in HLA-DR4 transgenic mice despite forming relatively unstable MHC-peptide complexes highly susceptible to HLA-DM editing. We attempted to improve the immunogenicity of QNT-5 by replacing the P1 anchor position with an optimal tyrosine residue. The modified peptide QNT-Y formed stable MHC-peptide complexes highly resistant to HLA-DM editing. Contrary to expectations, a linear peptide containing QNT-Y elicited almost 10-fold lower long-term antibody and IFN-γ responses compared to the linear peptide containing the wild type QNT-5 sequence. Some possibilities regarding why QNT-5 is more effective than QNT-Y in inducing long-term T cell and anti-CS Ab when used as vaccine are discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Promiscuous survivin peptide induces robust CD4+ T-cell responses in the majority of vaccinated cancer patients.

    Science.gov (United States)

    Widenmeyer, Melanie; Griesemann, Heinrich; Stevanović, Stefan; Feyerabend, Susan; Klein, Reinhild; Attig, Sebastian; Hennenlotter, Jörg; Wernet, Dorothee; Kuprash, Dmitri V; Sazykin, Alexei Y; Pascolo, Steve; Stenzl, Arnulf; Gouttefangeas, Cécile; Rammensee, Hans-Georg

    2012-07-01

    CD4(+) T cells have been shown to be crucial for the induction and maintenance of cytotoxic T cell responses and to be also capable of mediating direct tumor rejection. Therefore, the anticancer therapeutic efficacy of peptide-based vaccines may be improved by addition of HLA class II epitopes to stimulate T helper cells. Survivin is an apoptosis inhibiting protein frequently overexpressed in tumors. Here we describe the first immunological evaluation of a survivin-derived CD4(+) T cell epitope in a multipeptide immunotherapy trial for prostate carcinoma patients. The survivin peptide is promiscuously presented by several human HLA-DRB1 molecules and, most importantly, is naturally processed by dendritic cells. In vaccinated patients, it was able to induce frequent, robust and multifunctional CD4(+) T cell responses, as monitored by IFN-γ ELISPOT and intracellular cytokine staining. Thus, this HLA-DR restricted epitope is broadly immunogenic and should be valuable for stimulating T helper cells in patients suffering from a wide range of tumors. Copyright © 2011 UICC.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Strong vaccine-induced CD8 T-cell responses have cytolytic function in a chimpanzee clearing HCV infection.

    Directory of Open Access Journals (Sweden)

    Babs E Verstrepen

    Full Text Available 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.

  14. Prolonged antigen presentation is required for optimal CD8+ T cell responses against malaria liver stage parasites.

    Directory of Open Access Journals (Sweden)

    Ian A Cockburn

    2010-05-01

    Full Text Available Immunization with irradiated sporozoites is currently the most effective vaccination strategy against liver stages of malaria parasites, yet the mechanisms underpinning the success of this approach are unknown. Here we show that the complete development of protective CD8+ T cell responses requires prolonged antigen presentation. Using TCR transgenic cells specific for the malaria circumsporozoite protein, a leading vaccine candidate, we found that sporozoite antigen persists for over 8 weeks after immunization--a remarkable finding since irradiated sporozoites are incapable of replication and do not differentiate beyond early liver stages. Persisting antigen was detected in lymphoid organs and depends on the presence of CD11c+ cells. Prolonged antigen presentation enhanced the magnitude of the CD8+ T cell response in a number of ways. Firstly, reducing the time primed CD8+ T cells were exposed to antigen in vivo severely reduced the final size of the developing memory population. Secondly, fully developed memory cells expanded in previously immunized mice but not when transferred to naïve animals. Finally, persisting antigen was able to prime naïve cells, including recent thymic emigrants, to become functional effector cells capable of eliminating parasites in the liver. Together these data show that the optimal development of protective CD8+ T cell immunity against malaria liver stages is dependent upon the prolonged presentation of sporozoite-derived antigen.

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

    DEFF Research Database (Denmark)

    Kloverpris, Henrik; Karlsson, Ingrid; Bonde, Jesper

    2009-01-01

    with seven CD8 T-cell epitopes and three CD4 T-cell epitopes. Epitope-specific responses were evaluated by intracellular cytokine staining for interferon-gamma, tumor necrosis factor alpha and interleukin-2 and/or pentamer labeling 3 weeks prior to, 10 weeks after and 32 weeks after the first immunization....... RESULTS:: Previously undetected T-cell responses specific for one or more epitopes were induced in all 12 individuals. Half of the participants had sustained CD4 T-cell responses 32 weeks after immunization. No severe adverse effects were observed. No overall or sustained change in viral load or CD4 T...

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

    Directory of Open Access Journals (Sweden)

    Stephen A Kaba

    Full Text Available 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.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.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.

  17. An Arthritis-Suppressive and Treg Cell-Inducing CD4+ T Cell Epitope is Functional in the Context of HLA-Restricted T Cell Responses

    NARCIS (Netherlands)

    De Wolf, Charlotte; Van Der Zee, Ruurd; Den Braber, Ineke; Glant, Tibor; Maill??re, Bernard; Favry, Emmanuel; Van Lummel, Menno; Koning, Frits; Hoek, Aad; Ludwig, Irene; Van Eden, Willem; Broere, Femke

    2016-01-01

    Previously, we have shown that mycobacterial heat shock protein 70 (HSP70)-derived peptide B29 induces B29-specific regulatory T cells, which suppressed experimental arthritis in mice by cross-recognition of their mammalian HSP70 homologs (1). The aim of this study is to characterize the B29 binding

  18. Interleukin-2 promotes antigenic reactivity of rested T cells but prolongs the postactivational refractory phase of activated T cells.

    Science.gov (United States)

    Norris, M S; McConnell, T J; Mannie, M D

    2001-07-10

    IL-2 is a principal autocrine growth factor that promotes T-cell activation and proliferation. However, IL-2 has also been implicated as a key intermediate in the induction and maintenance of self-tolerance in vivo. The purpose of this study was to assess whether the differential regulatory activity of IL-2 was related to the activation status of responder T cells. In cultures of rested myelin basic protein (MBP)-specific T cells, IL-2 not only induced IL-2R alpha but also augmented surface expression of several other activation-associated glycoproteins including OX40, LFA-1, B7.1, B7.2, TCR, and CD4. Pretreatment of T cells with IL-2 also up-regulated subsequent antigen reactivity in assays of MBP-stimulated proliferation and IL-2 production and also promoted proliferative responsiveness to IL-2. In cultures of activated T cells, however, IL-2 inhibited subsequent reactivity to antigen or IL-2 and thereby prolonged a phase of postactivational refractoriness. Exposure of preactivated T cells to IL-2 also inhibited subsequent responses to the mitogenic combination of PMA, ionomycin, and IL-2 without enhancing cell death. These data support the concept that the inhibitory activity of IL-2 is dependent upon the activation status of T cells and is manifest as impaired cell cycle progression in response to a variety of IL-2-dependent stimuli. Copyright 2001 Academic Press.

  19. Modification of the intestinal postirradiation proliferative response by intraabdominal H-4-II-E2 tumors

    International Nuclear Information System (INIS)

    Evans, M.J.; Kovacs, C.J.; Schenken, L.L.; Burholt, D.R.

    1981-01-01

    Intraperitoneal injection of H-4-II-E 2 tumor cells gave rise to a number of individually growing intraabdominal tumors concentrated at sites of high abdominal vascularization. During tumor growth, both tumor and intestinal crypt cell proliferative activity were progressively depressed. A linear reduction of [ 3 H]TdR incorporation occurred in individual tumors independent of tumor size, suggesting that total tumor burden determines the proliferative status of individual tumors. Cytokinetic jejunal crypt analyses indicated that both a reduction in crypt cellularity and an abbreviated cell cycle transit time were noted during the depression of proliferative activity in the jejunum. In tumor-bearing rats the migration rate of cells from the jejunal crypt through the villus was reduced in response to a reduction in total cell production in the crypt. The life span of the epithelial cell in both tumor-bearing and normal rats was similar due to a reduction in villus cellularity in the tumor-bearing animals. Following abdominal irradiation of the tumor, the magnitude, but not the time course of hyperproliferative intestinal recovery, was influenced by the tumor mass. For nontumor-bearing animals, maximal hyperproliferation (>200% of control) occurred 96 hr postradiation. With increasing tumor burden the compensatory proliferative response to radiation was progressively reduced

  20. Distinct modulation of allergic T cell responses by subcutaneous versus sublingual allergen-specific immunotherapy

    DEFF Research Database (Denmark)

    Schulten, Véronique; Tripple, Victoria; Andersen, Kristian Aasbjerg

    2016-01-01

    10 months of treatment compared to baseline was detected in both treatment groups. FACS analysis revealed that IL-10 production was associated with CD4(+) T cells that also produced IFNγ, and therefore may be associated with an IL-10-secreting type 1 cell phenotype. CONCLUSION AND CLINICAL RELEVANCE...

  1. CD1c tetramers detect ex vivo T cell responses to processed phosphomycoketide antigens

    NARCIS (Netherlands)

    Ly, Dalam; Kasmar, Anne G.; Cheng, Tan-Yun; de Jong, Annemieke; Huang, Shouxiong; Roy, Sobhan; Bhatt, Apoorva; van Summeren, Ruben P.; Altman, John D.; Jacobs, William R.; Adams, Erin J.; Minnaard, Adriaan J.; Porcelli, Steven A.; Moody, Branch; Jacobs Jr., William R.

    2013-01-01

    CD1c is expressed with high density on human dendritic cells (DCs) and B cells, yet its antigen presentation functions are the least well understood among CD1 family members. Using a CD1c-reactive T cell line (DN6) to complete an organism-wide survey of M. tuberculosis lipids, we identified C32

  2. Polyfunctional CD4+ T cell responses to a set of pathogenic arenaviruses provide broad population coverage

    OpenAIRE

    Kotturi, Maya F; Botten, Jason; Maybeno, Matt; Sidney, John; Glenn, Jean; Bui, Huynh-Hoa; Oseroff, Carla; Crotty, Shane; Peters, Bjoern; Grey, Howard; Altmann, Daniel M; Buchmeier, Michael J; Sette, Alessandro

    2010-01-01

    Abstract Background Several arenaviruses cause severe hemorrhagic fever and aseptic meningitis in humans for which no licensed vaccines are available. A major obstacle for vaccine development is pathogen heterogeneity within the Arenaviridae family. Evidence in animal models and humans indicate that T cell and antibody-mediated immunity play important roles in controlling arenavirus in...

  3. Tolerization of an established αb-crystallin-reactive T-cell response by intravenous antigen

    NARCIS (Netherlands)

    Verbeek, R.; Mark, K. van der; Wawrousek, E.F.; Plomp, A.C.; Noort, J.M. van

    2007-01-01

    Tolerance induction to prevent activation of a naïve T-cell repertoire has been well documented in rodents and can be readily achieved by intravenous, oral or intranasal administration of antigen in the absence of adjuvants. In autoimmune diseases such as multiple sclerosis (MS) the presence of an

  4. CCR9+ T cells contribute to the resolution of the inflammatory response in a mouse model of intestinal amoebiasis.

    Science.gov (United States)

    Rojas-López, A E; Soldevila, G; Meza-Pérez, S; Dupont, G; Ostoa-Saloma, P; Wurbel, M A; Ventura-Juárez, J; Flores-Romo, L; García-Zepeda, E A

    2012-08-01

    Analysis of the mechanisms underlying the inflammatory response in amoebiasis is important to understand the immunopathology of the disease. Mucosal associated effector and regulatory T cells may play a role in regulating the inflammatory immune response associated to Entamoeba histolytica infection in the colon. A subpopulation of regulatory T cells has recently been identified and is characterized by the expression of the chemokine receptor CCR9. In this report, we used CCR9 deficient (CCR9(-/-)) mice to investigate the role of the CCR9(+) T cells in a murine model of E. histolytica intestinal infection. Intracecal infection of CCR9(+/+), CCR9(+/-) and CCR9(-/-) mice with E. histolytica trophozoites, revealed striking differences in the development and nature of the intestinal inflammatory response observed between these strains. While CCR9(+/+) and CCR9(+/-) mice were resistant to the infection and resolved the pathogen-induced inflammatory response, CCR9(-/-) mice developed a chronic inflammatory response, which was associated with over-expression of the cytokines IFN-γ, TNF-α, IL-4, IL-6 and IL-17, while IL-10 was not present. In addition, increased levels of CCL11, CCL20 and CCL28 chemokines were detected by qRT-PCR in CCR9(-/-) mice. E. histolytica trophozoites were identified in the lumen of the cecum of CCR9(-/-) mice at seven days post infection (pi), whereas in CCR9(+/+) mice trophozoites disappeared by day 1 pi. Interestingly, the inflammation observed in CCR9(-/-) mice, was associated with a delayed recruitment of CD4(+)CD25(+)FoxP3(+) T cells to the cecal epithelium and lamina propria, suggesting that this population may play a role in the early regulation of the inflammatory response against E. histolytica, likely through IL-10 production. In support of these data, CCR9(+) T cells were also identified in colon tissue sections obtained from patients with amoebic colitis. Our data suggest that a population of CCR9(+)CD4(+)CD25(+)FoxP3(+) T cells may

  5. The descrease of the in vitro proliferative response of zinc-treated stressed mice's thymic lymphocytes.

    Science.gov (United States)

    García-Tamayo, F; Malpica López, N; Aguirre, M; Terrazas-Valdés, L I

    1999-01-01

    Prolonged stimulation of newborn mice by intraperitoneal injections with inactivated staphylococci induces a chronic neonatal inflammatory reaction and an associated oxidative-stress response. The chronically stimulated animals exhibit anorexy. show a reduction in their body weight and undergo a depression in both antibody synthesis andin vitro proliferativc response of Con A-stimulated splenic T-lymphocytes. These stressed animals also develop adrenal hyperplasia, hypozincamia and thymic hypoplasia. Despite this stress-mediated thymic involution, Con-A stimulated T-lymphocytes from thymus displayed increased theirin vitro proliferative response. Results of the present work show that intramuscular injections of zinc acetate in stressed mice, one single dose (5 microg) every other day for two weeks, reduce both the zinc concentration in the thymus gland and thein vitro proliferative response of their Con A-stimulated T-lymphocytes. The results suggest that prophylactic administration of zinc can have benefical consequences on the immunity of chronically stressed mice.

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

    Directory of Open Access Journals (Sweden)

    Amita Joshi

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

  7. Mathematical modeling of interleukin-27 induction of anti-tumor T cells response.

    Directory of Open Access Journals (Sweden)

    Kang-Ling Liao

    Full Text Available Interleukin-12 is a pro-inflammatory cytokine which promotes Th1 and cytotoxic T lymphocyte activities, such as Interferon-[Formula: see text] secretion. For this reason Interleukin-12 could be a powerful therapeutic agent for cancer treatment. However, Interleukin-12 is also excessively toxic. Interleukin-27 is an immunoregulatory cytokine from the Interleukin-12 family, but it is not as toxic as Interleukin-12. In recent years, Interleukin-27 has been considered as a potential anti-tumor agent. Recent experiments in vitro and in vivo have shown that cancer cells transfected with IL-27 activate CD8+ T cells to promote the secretion of anti-tumor cytokines Interleukin-10, although, at the same time, IL-27 inhibits the secretion of Interferon-[Formula: see text] by CD8+ T cells. In the present paper we develop a mathematical model based on these experimental results. The model involves a dynamic network which includes tumor cells, CD8+ T cells and cytokines Interleukin-27, Interleukin-10 and Interferon-[Formula: see text]. Simulations of the model show how Interleukin-27 promotes CD8+ T cells to secrete Interleukin-10 to inhibit tumor growth. On the other hand Interleukin-27 inhibits the secretion of Interferon-[Formula: see text] by CD8+ T cells which somewhat diminishes the inhibition of tumor growth. Our numerical results are in qualitative agreement with experimental data. We use the model to design protocols of IL-27 injections for the treatment of cancer and find that, for some special types of cancer, with a fixed total amount of drug, within a certain range, continuous injection has better efficacy than intermittent injections in reducing the tumor load while the treatment is ongoing, although the decrease in tumor load is only temporary.

  8. Antigen recognition and immunomodulation by gamma delta T cells in bovine tuberculosis.

    Science.gov (United States)

    Rhodes, S G; Hewinson, R G; Vordermeier, H M

    2001-05-01

    This report describes the in vitro proliferative responses of peripheral blood gammadelta T cells to defined mycobacterial protein Ags and the immunomodulatory effect of gammadelta T cells in cattle infected with Mycobacterium bovis. gammadelta T cell responses were specific to M. bovis infection because they were detected in cattle either experimentally or naturally infected with M. bovis, but were not present in uninfected controls. Proliferating gammadelta T cell cultures produced enhanced levels of IFN-gamma and TGF-beta, but not IL-2 in response to the more immunodominant mycobacterial AGS: Depletion of gammadelta T cells from PBMC resulted in an increased Ag-specific proliferation in half the animals tested, indicating a suppressive effect of gammadelta T cells upon other (alphabeta) T cell responses. Because gammadelta T cells constitute a major T cell population in the peripheral blood of cattle, the activities of gammadelta T cells described in this report could make a significant contribution to the immune response in bovine tuberculosis.

  9. Global transcriptional characterization of CD8+ T cell memory.

    Science.gov (United States)

    Böttcher, Jan; Knolle, Percy A

    2015-02-01

    The differentiation of memory CD8T cells after acute infections comprises generation of functionally distinct populations that either have proliferative potential or display cytotoxic effector functions and that either recirculate into lymphoid tissues or remain tissue-resident. The development of these functionally distinct cell populations is dictated by defined signals from the microenvironment that result in a coordinated expression of a network of transcription factors, which determine the functionality of memory T cells. Distinct transcriptional regulation observed during chronic viral infection that results in generation of T cells that control viral replication in the absence of immunopathology suggests the existence of so far unappreciated functional adaptation of T cell function to the particular need during chronic infections to control infection and avoid immunopathology. Furthermore, the non-canonical generation of CD8T cell memory outside of lymphoid tissues in the liver in the absence of inflammation is correlated with a distinct transcriptional profile and indicates further complexity in the commensurate immune response to infectious pathogens that escape innate immunity. Taken together, distinct profiles of transcriptional regulation are linked to CD8T cells with different functions and provide important mechanistic insight into the continuous functional adaptation of CD8T cells to generate a commensurate immune response to infectious challenges. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Antibody-independent control of gamma-herpesvirus latency via B cell induction of anti-viral T cell responses.

    Directory of Open Access Journals (Sweden)

    Kelly B McClellan

    2006-06-01

    Full Text Available B cells can use antibody-dependent mechanisms to control latent viral infections. It is unknown whether this represents the sole function of B cells during chronic viral infection. We report here that hen egg lysozyme (HEL-specific B cells can contribute to the control of murine gamma-herpesvirus 68 (gammaHV68 latency without producing anti-viral antibody. HEL-specific B cells normalized defects in T cell numbers and proliferation observed in B cell-/- mice during the early phase of gammaHV68 latency. HEL-specific B cells also reversed defects in CD8 and CD4 T cell cytokine production observed in B cell-/- mice, generating CD8 and CD4 T cells necessary for control of latency. Furthermore, HEL-specific B cells were able to present virally encoded antigen to CD8 T cells. Therefore, B cells have antibody independent functions, including antigen presentation, that are important for control of gamma-herpesvirus latency. Exploitation of this property of B cells may allow enhanced vaccine responses to chronic virus infection.

  11. Emulsified phosphatidylserine, simple and effective peptide carrier for induction of potent epitope-specific T cell responses.

    Directory of Open Access Journals (Sweden)

    Toru Ichihashi

    Full Text Available BACKGROUND: To induce potent epitope-specific T cell immunity by a peptide-based vaccine, epitope peptides must be delivered efficiently to antigen-presenting cells (APCs in vivo. Therefore, selecting an appropriate peptide carrier is crucial for the development of an effective peptide vaccine. In this study, we explored new peptide carriers which show enhancement in cytotoxic T lymphocyte (CTL induction capability. METHODOLOGY/PRINCIPAL FINDINGS: Data from an epitope-specific in vivo CTL assay revealed that phosphatidylserine (PS has a potent adjuvant effect among candidate materials tested. Further analyses showed that PS-conjugated antigens were preferentially and efficiently captured by professional APCs, in particular, by CD11c(+CD11b(+MHCII(+ conventional dendritic cells (cDCs compared to multilamellar liposome-conjugates or unconjugated antigens. In addition, PS demonstrated the stimulatory capacity of peptide-specific helper T cells in vivo. CONCLUSIONS/SIGNIFICANCE: This work indicates that PS is the easily preparable efficient carrier with a simple structure that delivers antigen to professional APCs effectively and induce both helper and cytotoxic T cell responses in vivo. Therefore, PS is a promising novel adjuvant for T cell-inducing peptide vaccines.

  12. Emulsified phosphatidylserine, simple and effective peptide carrier for induction of potent epitope-specific T cell responses.

    Science.gov (United States)

    Ichihashi, Toru; Satoh, Toshifumi; Sugimoto, Chihiro; Kajino, Kiichi

    2013-01-01

    To induce potent epitope-specific T cell immunity by a peptide-based vaccine, epitope peptides must be delivered efficiently to antigen-presenting cells (APCs) in vivo. Therefore, selecting an appropriate peptide carrier is crucial for the development of an effective peptide vaccine. In this study, we explored new peptide carriers which show enhancement in cytotoxic T lymphocyte (CTL) induction capability. Data from an epitope-specific in vivo CTL assay revealed that phosphatidylserine (PS) has a potent adjuvant effect among candidate materials tested. Further analyses showed that PS-conjugated antigens were preferentially and efficiently captured by professional APCs, in particular, by CD11c(+)CD11b(+)MHCII(+) conventional dendritic cells (cDCs) compared to multilamellar liposome-conjugates or unconjugated antigens. In addition, PS demonstrated the stimulatory capacity of peptide-specific helper T cells in vivo. This work indicates that PS is the easily preparable efficient carrier with a simple structure that delivers antigen to professional APCs effectively and induce both helper and cytotoxic T cell responses in vivo. Therefore, PS is a promising novel adjuvant for T cell-inducing peptide vaccines.

  13. The primary response of human gamma/delta + T cells to Mycobacterium tuberculosis is restricted to V gamma 9-bearing cells

    OpenAIRE

    1991-01-01

    We have previously reported that peripheral blood gamma/delta + T cells proliferate in high frequency (1 in 2-20) in response to heat-killed Mycobacterium tuberculosis (M.tb.). In the present study, the T cell receptor phenotype of mycobacteria-responsive human gamma/delta + T cells was analyzed in primary cultures with a set of monoclonal antibodies (mAbs) directed against V gamma 9, V delta 1, and V delta 2. When unseparated T cells were stimulated with M.tb., all proliferating gamma/delta ...

  14. Novel primary thymic defect with T lymphocytes expressing gamma delta T cell receptor

    DEFF Research Database (Denmark)

    Geisler, C; Pallesen, G; Platz, P

    1989-01-01

    . Immunoprecipitation and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that most of the gamma delta T cell receptors existed as disulphide-linked heterodimers. Proliferative responses to mitogens were severely reduced, but specific antibody responses after vaccination could be detected...

  15. Involvement of CD8+ T cell-mediated immune responses in LcrV DNA vaccine induced protection against lethal Yersinia pestis challenge.

    Science.gov (United States)

    Wang, Shixia; Goguen, Jon D; Li, Fusheng; Lu, Shan

    2011-09-09

    Yersinia pestis (Y. pestis) is the causative pathogen of plague, a highly fatal disease for which an effective vaccine, especially against mucosal transmission, is still not available. Like many bacterial infections, antigen-specific antibody responses have been traditionally considered critical, if not solely responsible, for vaccine-induced protection against Y. pestis. Studies in recent years have suggested the importance of T cell immune responses against Y. pestis infection but information is still limited about the details of Y. pestis antigen-specific T cell immune responses. In current report, studies are conducted to identify the presence of CD8+ T cell epitopes in LcrV protein, the leading antigen of plague vaccine development. Furthermore, depletion of CD8+ T cells in LcrV DNA vaccinated Balb/C mice led to reduced protection against lethal intranasal challenge of Y. pestis. These findings establish that an LcrV DNA vaccine is able to elicit CD8+ T cell immune responses against specific epitopes of this key plague antigen and that a CD8+ T cell immune response is involved in LcrV DNA vaccine-elicited protection. Future studies in plague vaccine development will need to examine if the presence of detectable T cell immune responses, in particular CD8+ T-cell immune responses, will enhance the protection against Y. pestis in higher animal species or humans. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Combined Use of Mycobacterium tuberculosis–Specific CD4 and CD8 T-Cell Responses Is a Powerful Diagnostic Tool of Active Tuberculosis

    Science.gov (United States)

    Rozot, Virginie; Patrizia, Amelio; Vigano, Selena; Mazza-Stalder, Jesica; Idrizi, Elita; Day, Cheryl L.; Perreau, Matthieu; Lazor-Blanchet, Catherine; Ohmiti, Khalid; Goletti, Delia; Bart, Pierre-Alexandre; Hanekom, Willem; Scriba, Thomas J.; Nicod, Laurent; Pantaleo, Giuseppe; Harari, Alexandre

    2015-01-01

    Immune-based assays are promising tools to help to formulate diagnosis of active tuberculosis. A multiparameter flow cytometry assay assessing T-cell responses specific to Mycobacterium tuberculosis and the combination of both CD4 and CD8 T-cell responses accurately discriminated between active tuberculosis and latent infection. PMID:25362202

  17. Prognostic value of HIV-1 Gag-specific CD4+ T-cell responses for progression to AIDS analyzed in a prospective cohort study

    NARCIS (Netherlands)

    Jansen, Christine A.; de Cuyper, Iris M.; Hooibrink, Berend; van der Bij, Akke K.; van Baarle, Debbie; Miedema, Frank

    2006-01-01

    The causal relationship between HIV-specific CD4+ T-cell responses and viral control and the effect of these responses on the natural history of HIV infection is unclear. In a detailed longitudinal study, functional HIV-1 Gag-specific CD4+ T cells were analyzed in long-term asymptomatic individuals

  18. Antigen entrapped in the escheriosomes leads to the generation of CD4(+) helper and CD8(+) cytotoxic T cell response.

    Science.gov (United States)

    Syed, Faisal M; Khan, Masood A; Nasti, Tahseen H; Ahmad, Nadeem; Mohammad, Owais

    2003-06-02

    In previous study, we demonstrated the potential of Escherichia coli (E. coli) lipid liposomes (escheriosomes) to undergo membrane-membrane fusion with cytoplasmic membrane of the target cells including professional antigen presenting cells. Our present study demonstrates that antigen encapsulated in escheriosomes could be successfully delivered simultaneously to the cytosolic as well as endosomal processing pathways of antigen presenting cells, leading to the generation of both CD4(+) T-helper and CD8(+) cytotoxic T cell response. In contrast, encapsulation of same antigen in egg phosphatidyl-choline (egg PC) liposomes, just like antigen-incomplete Freund's adjuvant (IFA) complex, has inefficient access to the cytosolic pathway of MHC I-dependent antigen presentation and failed to generate antigen-specific CD8(+) cytotoxic T cell response. However, both egg PC liposomes as well as escheriosomes-encapsulated antigen elicited strong humoral immune response in immunized animals but antibody titre was significantly higher in the group of animals immunized with escheriosomes-encapsulated antigen. These results imply usage of liposome-based adjuvant as potential candidate vaccine capable of eliciting both cell-mediated as well as humoral immune responses. Furthermore, antigen entrapped in escheriosomes stimulates antigen-specific CD4(+) T cell proliferation and also enhances the level of IL-2, IFN-gamma and IL-4 in the immunized animals.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    Development of methods for efficient in vitro stimulation and expansion of peptide specific CD8(+) T cells is compelling not only with respect to adoptive T cell therapy but also regarding analysis of T cell responses and search for new immunogenic peptides. In the present study, a new approach...... cells (NA-PBMCs) with PB-MHC/CMVp resulted in significant expansion of CMVp specific CD8(+) T cells, which was comparable to that achieved by CMVp pulsed mature dendritic cells (DCs). By repeated exposure of NA-PBMCs to PB-MHC/CMVp more than 60% CMVp specific CD8(+) T cells, representing a 240-fold...... expansion, were reached after only two stimulations. Although stimulation with PB-MHC/CMVp clearly demonstrated efficient peptide specific expansion of CD8(+) T cells, there was a tendency to proliferative exhaustion of the cells after 3-4 stimulations. Thus, it will be of interest to examine the effect...

  20. Evaluating prediction strategies for identification of T cell responsive mutation-derived neoepitopesin cancer

    DEFF Research Database (Denmark)

    Andersen, Malene Rask; Bjerregaard, Anne-Mette; Fugmann, T.

    2016-01-01

    Increasing evidences point to an important role of mutation-derived antigens in immune recognition of cancer. Current strategies for prediction of immunogenic neoepitopes results in large personalized peptide libraries, but only a minority (... a study in which all the above mentioned strategies are assessed in three melanoma patients. Predicted large peptide libraries matching the HLA expression of the patients was identified and selected based on any of the strategies given above. This resulted in a total of ~3000 peptides for the three...... patients. We investigated the T cell recognition of these personalized peptide libraries using a new technology based on DNA-barcode labeled MHC multimers to detect multiple, potentially > 1000, different neoepitope specific T cell populations in a single sample. Through this unbiased comparison, we...

  1. T Cell Response in Patients with Implanted Biological and Mechanical Prosthetic Heart Valves.

    Science.gov (United States)

    Barbarash, L; Kudryavtsev, I; Rutkovskaya, N; Golovkin, A

    2016-01-01

    The study was aimed at assessing T cell subsets of peripheral blood from recipients of long-term functioning (more than 60 months) biological and mechanical heart valve prostheses. The absolute and relative number of CD4 and CD8 T cell subsets was analyzed: naïve (N, CD45RA(+)CD62L(+)), central memory (CM, CD45RA(-)CD62L(+)), effector memory (EM, CD45RA(-)CD62L(-)), and terminally differentiated CD45RA-positive effector memory (TEMRA, CD45RA(+)CD62L(-)) in 25 persons with biological and 7 with mechanical prosthesis compared with 48 apparently healthy volunteers. The relative and absolute number of central memory and naïve CD3(+)CD8(+) in patients with biological prosthesis was decreased (p biological heart valve prostheses.

  2. Pentoxifylline reverses chronic experimental Chagasic cardiomyopathy in association with repositioning of abnormal CD8+ T-cell response.

    Directory of Open Access Journals (Sweden)

    Isabela Resende Pereira

    2015-03-01

    Full Text Available Chronic chagasic cardiomyopathy (CCC, the main clinical sign of Chagas disease, is associated with systemic CD8+ T-cell abnormalities and CD8-enriched myocarditis occurring in an inflammatory milieu. Pentoxifylline (PTX, a phosphodiesterase inhibitor, has immunoregulatory and cardioprotective properties. Here, we tested PTX effects on CD8+ T-cell abnormalities and cardiac alterations using a model of experimental Chagas' heart disease.C57BL/6 mice chronically infected by the Colombian Trypanosoma cruzi strain and presenting signs of CCC were treated with PTX. The downmodulation of T-cell receptors on CD8+ cells induced by T. cruzi infection was rescued by PTX therapy. Also, PTX reduced the frequency of CD8+ T-cells expressing activation and migration markers in the spleen and the activation of blood vessel endothelial cells and the intensity of inflammation in the heart tissue. Although preserved interferon-gamma production systemically and in the cardiac tissue, PTX therapy reduced the number of perforin+ cells invading this tissue. PTX did not alter parasite load, but hampered the progression of heart injury, improving connexin 43 expression and decreasing fibronectin overdeposition. Further, PTX reversed electrical abnormalities as bradycardia and prolonged PR, QTc and QRS intervals in chronically infected mice. Moreover, PTX therapy improved heart remodeling since reduced left ventricular (LV hypertrophy and restored the decreased LV ejection fraction.PTX therapy ameliorates critical aspects of CCC and repositioned CD8+ T-cell response towards homeostasis, reinforcing that immunological abnormalities are crucially linked, as cause or effect, to CCC. Therefore, PTX emerges as a candidate to treat the non-beneficial immune deregulation associated with chronic Chagas' heart disease and to improve prognosis.

  3. Pentoxifylline Reverses Chronic Experimental Chagasic Cardiomyopathy in Association with Repositioning of Abnormal CD8+ T-Cell Response

    Science.gov (United States)

    Pereira, Isabela Resende; Vilar-Pereira, Glaucia; Moreira, Otacilio Cruz; Ramos, Isalira Peroba; Gibaldi, Daniel; Britto, Constança; Moraes, Milton Ozório; Lannes-Vieira, Joseli

    2015-01-01

    Background Chronic chagasic cardiomyopathy (CCC), the main clinical sign of Chagas disease, is associated with systemic CD8+ T-cell abnormalities and CD8-enriched myocarditis occurring in an inflammatory milieu. Pentoxifylline (PTX), a phosphodiesterase inhibitor, has immunoregulatory and cardioprotective properties. Here, we tested PTX effects on CD8+ T-cell abnormalities and cardiac alterations using a model of experimental Chagas’ heart disease. Methodology/Principal Findings C57BL/6 mice chronically infected by the Colombian Trypanosoma cruzi strain and presenting signs of CCC were treated with PTX. The downmodulation of T-cell receptors on CD8+ cells induced by T. cruzi infection was rescued by PTX therapy. Also, PTX reduced the frequency of CD8+ T-cells expressing activation and migration markers in the spleen and the activation of blood vessel endothelial cells and the intensity of inflammation in the heart tissue. Although preserved interferon-gamma production systemically and in the cardiac tissue, PTX therapy reduced the number of perforin+ cells invading this tissue. PTX did not alter parasite load, but hampered the progression of heart injury, improving connexin 43 expression and decreasing fibronectin overdeposition. Further, PTX reversed electrical abnormalities as bradycardia and prolonged PR, QTc and QRS intervals in chronically infected mice. Moreover, PTX therapy improved heart remodeling since reduced left ventricular (LV) hypertrophy and restored the decreased LV ejection fraction. Conclusions/Significance PTX therapy ameliorates critical aspects of CCC and repositioned CD8+ T-cell response towards homeostasis, reinforcing that immunological abnormalities are crucially linked, as cause or effect, to CCC. Therefore, PTX emerges as a candidate to treat the non-beneficial immune deregulation associated with chronic Chagas' heart disease and to improve prognosis. PMID:25789471

  4. Targeting of non-dominant antigens as a vaccine strategy to broaden T-cell responses during chronic viral infection

    DEFF Research Database (Denmark)

    Holst, Peter Johannes; Jensen, Benjamin Anderschou Holbech; Ragonnaud, Emeline

    2015-01-01

    challenge with live virus, the CD8+ T cells specific for vaccine-encoded epitopes, displayed a phenotype typically associated with prolonged/persistent antigenic stimulation marked by high levels of KLRG-1, as compared to T cells reacting to epitopes not included in the vaccine. Notably, this association...... by vaccination. In addition, our findings suggest that prior adenoviral vaccination is not likely to negatively impact the long-term and protective immune response induced and maintained by a vaccine-attenuated chronic viral infection.......In this study, we compared adenoviral vaccine vectors with the capacity to induce equally potent immune responses against non-dominant and immunodominant epitopes of murine lymphocytic choriomeningitis virus (LCMV). Our results demonstrate that vaccination targeting non-dominant epitopes...

  5. An Analysis of Natural T Cell Responses to Predicted Tumor Neoepitopes

    DEFF Research Database (Denmark)

    Bjerregaard, Anne-Mette; Nielsen, Morten; Jurtz, Vanessa Isabell

    2017-01-01

    Personalization of cancer immunotherapies such as therapeutic vaccines and adoptive T-cell therapy may benefit from efficient identification and targeting of patient-specific neoepitopes. However, current neoepitope prediction methods based on sequencing and predictions of epitope processing and ...... predicted binding strength. In conclusion, these results suggest new strategies for prioritization of mutated peptides, but new data will be needed to confirm their value....

  6. T Cell Response in Patients with Implanted Biological and Mechanical Prosthetic Heart Valves

    Directory of Open Access Journals (Sweden)

    L. Barbarash

    2016-01-01

    Full Text Available The study was aimed at assessing T cell subsets of peripheral blood from recipients of long-term functioning (more than 60 months biological and mechanical heart valve prostheses. The absolute and relative number of CD4 and CD8 T cell subsets was analyzed: naïve (N, CD45RA+CD62L+, central memory (CM, CD45RA−CD62L+, effector memory (EM, CD45RA−CD62L−, and terminally differentiated CD45RA-positive effector memory (TEMRA, CD45RA+CD62L− in 25 persons with biological and 7 with mechanical prosthesis compared with 48 apparently healthy volunteers. The relative and absolute number of central memory and naïve CD3+CD8+ in patients with biological prosthesis was decreased (p<0.001. Meanwhile the number of CD45RA+CD62L−CD3+CD8+ and CD3+CD4+ was increased (p<0.001. Patients with mechanical prosthesis had increased absolute and relative number of CD45RA+CD62L−CD3+CD8+ cells (p=0.006. Also the relative number of CD3+CD4+ cells was reduced (p=0.04. We assume that altered composition of T cell subsets points at development of xenograft rejection reaction against both mechanical and biological heart valve prostheses.

  7. Characterization of the Specific CD4+ T Cell Response against the F Protein during Chronic Hepatitis C Virus Infection

    OpenAIRE

    Gao, De-Yong; Jin, Gen-Di; Yao, Bi-Lian; Zhang, Dong-Hua; Gu, Lei-Lei; Lu, Zhi-Meng; Gong, Qiming; Lone, Yu-Chun; Deng, Qiang; Zhang, Xin-Xin

    2010-01-01

    International audience; BACKGROUND: The hepatitis C virus (HCV) Alternate Reading Frame Protein (ARFP or F protein) presents a double-frame shift product of the HCV core gene. We and others have previously reported that the specific antibodies against the F protein could be raised in the sera of HCV chronically infected patients. However, the specific CD4(+) T cell responses against the F protein during HCV infection and the pathological implications remained unclear. In the current study, we...

  8. Diverse patterns of T-cell response against multiple newly identified human Y chromosome-encoded minor histocompatibility epitopes.

    Science.gov (United States)

    Ofran, Yishai; Kim, Haesook T; Brusic, Vladimir; Blake, Loren; Mandrell, Michael; Wu, Catherine J; Sarantopoulos, Stefanie; Bellucci, Roberto; Keskin, Derin B; Soiffer, Robert J; Antin, Joseph H; Ritz, Jerome

    2010-03-01

    Donor T cells respond to minor histocompatibility antigens (mHA), resulting in both graft-versus-host disease and graft versus leukemia after allogeneic hematopoietic stem cell transplantation. Because relatively few mHAs are known, we developed a new approach to predict and subsequently validate candidate mHA. We developed an algorithm based on genetic disparities between Y chromosome-encoded and X chromosome-encoded proteins and known requirements for binding to HLA class I molecules to predict Y chromosome-derived, HLA A*0201-restricted peptides (HY) and ranked peptides based on potential immunogenicity. We evaluated T-cell responses to 41 candidate peptides in 28 male recipients with female donors (FM), 22 male recipients with male donors (MM), and 26 normal individuals. All patients and donors were HLA A*0201 positive. Thirteen peptides derived from five proteins elicited significantly greater T-cell responses in FM patients compared with MM patients and in normal females compared with normal males. Six peptides were more immunogenic than the only previously known HLA A*0201-restricted Y-encoded mHA. Twenty-seven of 28 FM patients responded to at least one HY peptide, but despite a common Y chromosome mismatch and expression of HLA A*0201, each patient responded to a unique set of peptides. Novel HLA A*0201-restricted HY epitopes can be predicted and validated in patients after allogeneic hematopoietic stem cell transplantation. Highly diverse patterns of T-cell response against these epitopes have been identified. Prospective monitoring of responses to large panels of immunogenic peptides can facilitate the identification of clinically relevant targets of graft-versus-host disease and graft versus leukemia.

  9. Immunosenescent CD57+CD4+ T-cells Accumulate and Contribute to Interferon-γ Responses in HIV Patients Responding Stably to ART

    Directory of Open Access Journals (Sweden)

    Sonia Fernandez

    2011-01-01

    Full Text Available HIV-infected individuals responding to antiretroviral therapy (ART after severe CD4+ T-cell depletion may retain low responses to recall antigens [eg: cytomegalovirus (CMV] and altered expression of T-cell co-stimulatory molecules consistent with immunosenescence. We investigated the capacity of phenotypically senescent cells to generate cytokines in HIV patients receiving long-term ART (n = 18 and in healthy controls (n = 10. Memory T-cells were assessed by interferon (IFN-γ ELISpot assay and flow cytometrically via IFN-γ or IL-2. Proportions of CD57brightCD28null CD4+ T-cells correlated with IFN-γ responses to CMV (p = 0.009 and anti-CD3 (p = 0.002 in HIV patients only. Proportions of CD57brightCD28null CD8+ T-cells and CD8+ T-cell IFN-γ responses to CMV peptides correlated in controls but not HIV patients. IL-2 was predominantly produced by CD28+T-cells from all donors, whereas IFN-γ was mostly produced by CD57+ T-cells. The findings provide evidence of an accumulation of immunosenescent T-cells able to make IFN-γ. This may influence the pathogenesis of secondary viral infections in HIV patients receiving ART.

  10. Hyperreactive onchocerciasis is characterized by a combination of Th17-Th2 immune responses and reduced regulatory T cells.

    Directory of Open Access Journals (Sweden)

    Gnatoulma Katawa

    2015-01-01

    Full Text Available Clinical manifestations in onchocerciasis range from generalized onchocerciasis (GEO to the rare but severe hyperreactive (HO/sowda form. Since disease pathogenesis is associated with host inflammatory reactions, we investigated whether Th17 responses could be related to aggravated pathology in HO. Using flow cytometry, filarial-specific cytokine responses and PCR arrays, we compared the immune cell profiles, including Th subsets, in individuals presenting the two polar forms of infection and endemic normals (EN. In addition to elevated frequencies of memory CD4+ T cells, individuals with HO showed accentuated Th17 and Th2 profiles but decreased CD4+CD25hiFoxp3+ regulatory T cells. These profiles included increased IL-17A+, IL-4+, RORC2+ and GATA3+CD4+ T cell populations. Flow cytometry data was further confirmed using a PCR array since Th17-related genes (IL-17 family members, IL-6, IL-1β and IL-22 and Th2-related (IL-4, IL-13, STAT6 genes were all significantly up-regulated in HO individuals. In addition, stronger Onchocerca volvulus-specific Th2 responses, especially IL-13, were observed in vitro in hyperreactive individuals when compared to GEO or EN groups. This study provides initial evidence that elevated frequencies of Th17 and Th2 cells form part of the immune network instigating the development of severe onchocerciasis.

  11. Impairment of the humoral and CD4+ T cell responses in HTLV-1-infected individuals immunized with tetanus toxoid

    Science.gov (United States)

    Souza, Anselmo; Santos, Silvane; Carvalho, Lucas P.; Grassi, Maria Fernanda R.; Carvalho, Edgar M.

    2016-01-01

    T cells from HTLV-1-infected individuals have a decreased ability to proliferate after stimulation with recall antigens. This abnormality may be due to the production of regulatory cytokine or a dysfunctional antigen presentation. The aims of this study were to evaluate the antibody production and cytokine expression by lymphocytes before and after immunization with tetanus toxoid (TT) and to evaluate the immune response of monocytes after stimulation with TT and frequency of dendritic cells (DC) subsets. HTLV-1 carriers (HC) and uninfected controls with negative serology for TT were immunized with TT, and the antibody titers were determined by ELISA as well as the cell activation markers expression by monocytes. The frequencies of DC subsets were determined by flow cytometry. Following immunization, the IgG anti-TT titers and the frequency of CD4+ T cells expressing IFN-γ, TNF and IL-10 in response to TT were lower in the (HC) than in the controls. Additionally, monocytes from HC did not exhibit increased HLA-DR expression after stimulation with TT, and presented low numbers of DC subsets, therefore, it’s necessary to perform functional studies with antigen-presenting cells. Collectively, our finding suggests that HC present an impairment of the humoral and CD4+ T cell immune responses after vaccination. PMID:27282836

  12. Impairment of the humoral and CD4(+) T cell responses in HTLV-1-infected individuals immunized with tetanus toxoid.

    Science.gov (United States)

    Souza, Anselmo; Santos, Silvane; Carvalho, Lucas P; Grassi, Maria Fernanda R; Carvalho, Edgar M

    2016-08-01

    T cells from HTLV-1-infected individuals have a decreased ability to proliferate after stimulation with recall antigens. This abnormality may be due to the production of regulatory cytokine or a dysfunctional antigen presentation. The aims of this study were to evaluate the antibody production and cytokine expression by lymphocytes before and after immunization with tetanus toxoid (TT) and to evaluate the immune response of monocytes after stimulation with TT and frequency of dendritic cells (DC) subsets. HTLV-1 carriers (HC) and uninfected controls (UC) with negative serology for TT were immunized with TT, and the antibody titers were determined by ELISA as well as the cell activation markers expression by monocytes. The frequencies of DC subsets were determined by flow cytometry. Following immunization, the IgG anti-TT titers and the frequency of CD4(+) T cells expressing IFN-γ, TNF-α and IL-10 in response to TT were lower in the HC than in the UC. Additionally, monocytes from HC did not exhibit increased HLA-DR expression after stimulation with TT, and presented low numbers of DC subsets, therefore, it's necessary to perform functional studies with antigen-presenting cells. Collectively, our finding suggests that HC present an impairment of the humoral and CD4(+) T cell immune responses after vaccination. Copyright © 2016 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

  13. In Vitro Responsiveness of γδ T Cells from Mycobacterium bovis-Infected Cattle to Mycobacterial Antigens: Predominant Involvement of WC1+ Cells

    Science.gov (United States)

    Smyth, Allister J.; Welsh, Michael D.; Girvin, R. Martyn; Pollock, John M.

    2001-01-01

    It is generally accepted that protective immunity against tuberculosis is generated through the cell-mediated immune (CMI) system, and a greater understanding of such responses is required if better vaccines and diagnostic tests are to be developed. γδ T cells form a major proportion of the peripheral blood mononuclear cells (PBMC) in the ruminant system and, considering data from other species, may have a significant role in CMI responses in bovine tuberculosis. This study compared the in vitro responses of αβ and γδ T cells from Mycobacterium bovis-infected and uninfected cattle. The results showed that, following 24 h of culture of PBMC with M. bovis-derived antigens, the majority of γδ T cells from infected animals became highly activated (upregulation of interleukin-2R), while a lower proportion of the αβ T-cell population showed activation. Similar responses were evident to a lesser degree in uninfected animals. Study of the kinetics of this response showed that γδ T cells remained significantly activated for at least 7 days in culture, while activation of αβ T cells declined during that period. Subsequent analysis revealed that the majority of activated γδ T cells expressed WC1, a 215-kDa surface molecule which is not expressed on human or murine γδ T cells. Furthermore, in comparison with what was found for CD4+ T cells, M. bovis antigen was found to induce strong cellular proliferation but relatively little gamma interferon release by purified WC1+ γδ T cells. Overall, while the role of these cells in protective immunity remains unclear, their highly activated status in response to M. bovis suggests an important role in antimycobacterial immunity, and the ability of γδ T cells to influence other immune cell functions remains to be elucidated, particularly in relation to CMI-based diagnostic tests. PMID:11119493

  14. Diethylstilbestrol alters positive and negative selection of T cells in the thymus and modulates T-cell repertoire in the periphery

    International Nuclear Information System (INIS)

    Brown, Nicole; Nagarkatti, Mitzi; Nagarkatti, Prakash S.

    2006-01-01

    Prenatal exposure to diethylstilbestrol (DES) is known to cause altered immune functions and increased susceptibility to autoimmune disease in humans. In the current study, we investigated the effects of DES on T-cell differentiation in the thymus using the HY-TCR transgenic (Tg) mouse model in which the female mice exhibit positive selection of T cells bearing the Tg TCR, while the male mice show negative selection of such T cells. In female HY-TCR-Tg mice, exposure to DES showed more pronounced decrease in thymic cellularity when compared to male mice. Additionally, female mice also showed a significant decrease in the proportion of double-positive (DP) T cells in the thymus and HY-TCR-specific CD8 + T cells in the periphery. Male mice exhibiting negative selection also showed decreased thymic cellularity following DES exposure. Moreover, the male mice showed increased proportion of double-negative (DN) T cells in the thymus and decreased proportion of CD8 + T cells. The density of expression of HY-TCR on CD8 + cells was increased following DES exposure in both females and males. Finally, the proliferative response of thymocytes to mitogens and peripheral lymph node T cells to male H-Y antigen was significantly altered in female and male mice following DES treatment. Taken together, these data suggest that DES alters T-cell differentiation in the thymus by interfering with positive and negative selection processes, which in turn modulates the T-cell repertoire in the periphery

  15. Autoantibodies in autoimmune thyroid disease promote immune complex formation with self antigens and increase B cell and CD4+ T cell proliferation in response to self antigens

    DEFF Research Database (Denmark)

    Nielsen, Claus Henrik; Hegedüs, Laszlo; Leslie, Robert Graham Quinton

    2004-01-01

    B cells are centrally involved as antigen-presenting cells in certain autoimmune diseases. To establish whether autoantibodies form immune complexes (IC) with self-antigens in autoimmune thyroid disease (AITD) and promote B cell uptake of self-antigen, sera from patients with Hashimoto's thyroidi......B cells are centrally involved as antigen-presenting cells in certain autoimmune diseases. To establish whether autoantibodies form immune complexes (IC) with self-antigens in autoimmune thyroid disease (AITD) and promote B cell uptake of self-antigen, sera from patients with Hashimoto......'s thyroiditis (HT), Graves' disease (GD) and healthy controls were incubated with human thyroglobulin (Tg) before adding normal peripheral blood mononuclear cells. The deposition of immunoglobulins and C3 fragments on B cells was then assessed. Inclusion of Tg in serum from HT patients promoted B cell capture...... of Tg by boiling reduced the proliferative responses. The data indicate that anti-Tg antibodies associated with AITD facilitate the formation of complement-activating Tg/anti-Tg complexes, binding of IC to B cells, and the subsequent proliferation of B and T cell subsets. This represents a novel...

  16. Plasmacytoid Dendritic Cells Mediate the Regulation of Inflammatory Type T Cell Response for Optimal Immunity against Respiratory Chlamydia Pneumoniae Infection

    Science.gov (United States)

    Joyee, Antony George; Yang, Xi

    2013-01-01

    Chlamydia pneumoniae (Cpn) infection is a leading cause for a variety of respiratory diseases and has been implicated in the pathogenesis of chronic inflammatory diseases. The regulatory mechanisms in host defense against Cpn infection are less understood. In this study, we investigated the role of plasmacytoid dendritic cells (pDCs) in immune regulation in Cpn respiratory tract infection. We found that in vivo depletion of pDCs increased the severity of infection and lung pathology. Mice depleted of pDC had greater body weight loss, higher lung bacterial burden and excessive tissue inflammation compared to the control mice. Analysis of specific T cell cytokine production pattern in the lung following Cpn infection revealed that pDC depleted mice produced significantly higher amounts of inflammatory cytokines, especially TNF-α, but lower IL-10 compared to the controls. In particular, pDC depleted mice showed pathogenic T cell responses characterized by inflammatory type-1 (CD8 and CD4) and inflammatory Th2 cell responses. Moreover, pDC depletion dramatically reduced CD4 regulatory T cells (Tregs) in the lungs and draining lymph nodes. Furthermore, pDC-T cell co-culture experiments showed that pDCs isolated from Cpn infected mice were potent in inducing IL-10 producing CD4 Tregs. Together, these findings provide in vivo evidence for a critical role of pDCs in homeostatic regulation of immunity during Cpn infection. Our findings highlight the importance of a ‘balanced’ immune response for host protective immunity and preventing detrimental immunopathology during microbial infections. PMID:24386207

  17. The contribution of non-conventional T cells and NK cells in the mycobacterial-specific IFNγ response in Bacille Calmette-Guerin (BCG-immunized infants.

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    Christel Zufferey

    Full Text Available BACKGROUND: The Mycobacterium bovis Bacille Calmette-Guérin (BCG vaccine is given to >120 million infants each year worldwide. Most studies investigating the immune response to BCG have focused on adaptive immunity. However the importance of TCR-gamma/delta (γδ T cells and NK cells in the mycobacterial-specific immune response is of increasing interest. METHODS: Participants in four age-groups were BCG-immunized. Ten weeks later, in vitro BCG-stimulated blood was analyzed for NK and T cell markers, and intracellular IFNgamma (IFNγ by flow cytometry. Total functional IFNγ response was calculated using integrated median fluorescence intensity (iMFI. RESULTS: In infants and children, CD4 and CD4-CD8- (double-negative (DN T cells were the main IFNγ-expressing cells representing 43-56% and 27-37% of total CD3+ IFNγ+ T cells respectively. The iMFI was higher in DN T cells compared to CD4 T cells in all age groups, with the greatest differences seen in infants immunized at birth (p=0.002 or 2 months of age (p<0.0001. When NK cells were included in the analysis, they accounted for the majority of total IFNγ-expressing cells and, together with DN Vδ2 γδ T cells, had the highest iMFI in infants immunized at birth or 2 months of age. CONCLUSION: In addition to CD4 T cells, NK cells and DN T cells, including Vδ2 γδ T cells, are the key populations producing IFNγ in response to BCG immunization in infants and children. This suggests that innate immunity and unconventional T cells play a greater role in the mycobacterial immune response than previously recognized and should be considered in the design and assessment of novel tuberculosis vaccines.

  18. Optimization of interferon gamma ELISPOT assay to detect human cytomegalovirus specific T-cell responses in solid organ transplants.

    Science.gov (United States)

    Abate, Davide; Saldan, Alda; Forner, Gabriella; Tinto, Daniel; Bianchin, Alice; Palù, Giorgio

    2014-02-01

    Assessing the CMV specific CMI in transplant subjects represents a promising strategy to determine the risk of infection on individual basis. In this study 61 adult CMV IgG seropositive solid organ transplant recipients were examined in order to improve the efficacy of CMI detection. For this purpose, pair-wise comparisons were conducted comparing positive control stimuli PWM and PMA/iono and CMV stimuli, pp65 peptide pool and whole CMV particle. Rosette pre-depletion of blood was also investigated for detecting CD4+ or CD8+ T-cell responses using the IFN-g ELISPOT assay. In the time-points 30-180 days after transplantation, PMA/iono produced statistically significant higher responses compared to PWM, probably because PMA/iono activation pathway is independent from the effect of immunosuppressive drugs. The data showed that 11% of transplant patients displayed very low or undetectable responses to pp65 peptide pool antigen while having sustained high responses to whole CMV particle. In addition, in all the subjects analyzed, CMI responses to CMV particle produced a statistically significant higher number of spots compared to pp65 peptide pool antigen. Rosette pre-depletion of whole blood proved to be effective in detecting CD4+ or CD8+ T-cell responses similarly to flow cytometry. Taken together, the following recommendations are suggested to optimize the CMV-ELISPOT for transplantation settings: (1) use PMA/iono as positive control; (2) whole virus particle should be used to avoid peptide-related false negative responses; (3) a rosette pre-depletion step may be useful to detect CD4+ or CD8+ T-cell responses. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. HLA Class I Binding 9mer Peptides from Influenza A Virus Induce CD4(+) T Cell Responses

    DEFF Research Database (Denmark)

    Wang, M. J.; Larsen, Mette Voldby; Nielsen, Morten

    2010-01-01

    Background: Identification of human leukocyte antigen class I (HLA-I) restricted cytotoxic T cell (CTL) epitopes from influenza virus is of importance for the development of new effective peptide-based vaccines. Methodology/Principal Findings: In the present work, bioinformatics was used to predict...... 9mer peptides derived from available influenza A viral proteins with binding affinity for at least one of the 12 HLA-I supertypes. The predicted peptides were then selected in a way that ensured maximal coverage of the available influenza A strains. One hundred and thirty one peptides were...... synthesized and their binding affinities for the HLA-I supertypes were measured in a biochemical assay. Influenza-specific T cell responses towards the peptides were quantified using IFN gamma ELISPOT assays with peripheral blood mononuclear cells (PBMC) from adult healthy HLA-I typed donors as responder...

  20. Hesperidin Inhibits Inflammatory Response Induced by Aeromonas hydrophila Infection and Alters CD4+/CD8+ T Cell Ratio

    Directory of Open Access Journals (Sweden)

    Abdelaziz S. A. Abuelsaad

    2014-01-01

    Full Text Available Background. Aeromonas hydrophila is an opportunistic bacterial pathogen that is associated with a number of human diseases. Hesperidin (HES has been reported to exert antioxidant and anti-inflammatory activities. Objectives. The aim of this study was to investigate the potential effect of HES treatment on inflammatory response induced by A. hydrophila infection in murine. Methods. A. hydrophila-infected mice were treated with HES at 250 mg/kg b.wt./week for 4 consecutive weeks. Phagocytosis, reactive oxygen species production, CD4+/CD8+ T cell ratio, and CD14 expression on intestinal infiltrating monocytes were evaluated. The expression of E-selectin and intercellular adhesion molecule 1 on stimulated HUVECs and RAW macrophage was evaluated. Results. Percentage of CD4+ T cells in the intestinal tissues of infected treated mice was highly significantly increased; however, phagocytic index, ROS production, CD8+ T cells percentage, and CD14 expression on monocytes were significantly reduced. On the other hand, HES significantly inhibited A-LPS- and A-ECP-induced E-selectin and ICAM-1 expression on HUVECs and ICAM-1 expression on RAW macrophage. Conclusion. Present data indicated that HES has a potential role in the suppression of inflammatory response induced by A. hydrophila toxins through downmodulation of ROS production and CD14 and adhesion molecules expression, as well as increase of CD4+/CD8+ cell ratio.

  1. Assessing the Prognostic Value of Preoperative Carcinoembryonic Antigen-Specific T-Cell Responses in Colorectal Cancer

    Science.gov (United States)

    Scurr, Martin J.; Brown, Clare M.; Costa Bento, Diana F.; Betts, Gareth J.; Rees, Brian I.; Hills, Robert K.; Gallimore, Awen; Godkin, Andrew

    2015-01-01

    Current dogma suggests that tumor-reactive IFN-γ–producing (TH1-type) T-cells are beneficial to patient outcome; however, the clinical consequence of these responses with respect to long-term prognosis in colorectal cancer (CRC) is not understood. Here, we compared the utility of preoperative, peripheral blood–derived IFN-γ+ T-cell responses specific to carcinoembryonic antigen (CEA), 5T4, or control antigens (n = 64) with tumor staging and clinical details (n = 87) in predicting five-year outcome of CRC patients who underwent resection with curative intent. Although disease recurrence was more likely in patients with stage III tumors, the presence of preoperative, CEA-specific IFN-γ–producing T-cells identified patients at a statistically significantly greater risk of tumor recurrence following surgical resection, irrespective of tumor stage (odds ratio = 5.00, 95% confidence interval = 1.96 to 12.77, two-sided P antigens, including 5T4, did not reflect outcome. Whilst these results initially appear surprising, they could improve prognostication and help redirect adjuvant treatments. PMID:25669203

  2. Toll-Like Receptor Mediated Modulation of T Cell Response by Commensal Intestinal Microbiota as a Trigger for Autoimmune Arthritis

    Directory of Open Access Journals (Sweden)

    Rebecca Rogier

    2015-01-01

    Full Text Available In autoimmune diseases, a disturbance of the balance between T helper 17 (Th17 and regulatory T cells (Tregs is often observed. This disturbed balance is also the case in rheumatoid arthritis (RA. Genetic predisposition to RA confers the presence of several polymorphisms mainly regulating activation of T lymphocytes. However, the presence of susceptibility factors is neither necessary nor sufficient to explain the disease development, emphasizing the importance of environmental factors. Multiple studies have shown that commensal gut microbiota is of great influence on immune homeostasis and can trigger the development of autoimmune diseases by favoring induction of Th17 cells over Tregs. However the mechanism by which intestinal microbiota influences the Th cell balance is not completely understood. Here we review the current evidence supporting the involvement of commensal intestinal microbiota in rheumatoid arthritis, along with a potential role of Toll-like receptors (TLRs in modulating the relevant Th cell responses to trigger autoimmunity. A better understanding of TLR triggering by intestinal microbiota and subsequent T cell activation might offer new perspectives for manipulating the T cell response in RA patients and may lead to the discovery of new therapeutic targets or even preventive measures.

  3. Variability in Tuberculosis Granuloma T Cell Responses Exists, but a Balance of Pro- and Anti-inflammatory Cytokines Is Associated with Sterilization

    Science.gov (United States)

    Gideon, Hannah Priyadarshini; Phuah, JiaYao; Myers, Amy J.; Bryson, Bryan D.; Rodgers, Mark A.; Coleman, M. Teresa; Maiello, Pauline; Rutledge, Tara; Marino, Simeone; Fortune, Sarah M.; Kirschner, Denise E.; Lin, Philana Ling; Flynn, JoAnne L.

    2015-01-01

    Lung granulomas are the pathologic hallmark of tuberculosis (TB). T cells are a major cellular component of TB lung granulomas and are known to play an important role in containment of Mycobacterium tuberculosis (Mtb) infection. We used cynomolgus macaques, a non-human primate model that recapitulates human TB with clinically active disease, latent infection or early infection, to understand functional characteristics and dynamics of T cells in individual granulomas. We sought to correlate T cell cytokine response and bacterial burden of each granuloma, as well as granuloma and systemic responses in individual animals. Our results support that each granuloma within an individual host is independent with respect to total cell numbers, proportion of T cells, pattern of cytokine response, and bacterial burden. The spectrum of these components overlaps greatly amongst animals with different clinical status, indicating that a diversity of granulomas exists within an individual host. On average only about 8% of T cells from granulomas respond with cytokine production after stimulation with Mtb specific antigens, and few “multi-functional” T cells were observed. However, granulomas were found to be “multi-functional” with respect to the combinations of functional T cells that were identified among lesions from individual animals. Although the responses generally overlapped, sterile granulomas had modestly higher frequencies of T cells making IL-17, TNF and any of T-1 (IFN-γ, IL-2, or TNF) and/or T-17 (IL-17) cytokines than non-sterile granulomas. An inverse correlation was observed between bacterial burden with TNF and T-1/T-17 responses in individual granulomas, and a combinatorial analysis of pair-wise cytokine responses indicated that granulomas with T cells producing both pro- and anti-inflammatory cytokines (e.g. IL-10 and IL-17) were associated with clearance of Mtb. Preliminary evaluation suggests that systemic responses in the blood do not accurately

  4. Influenza-specific T cells from older people are enriched in the late effector subset and their presence inversely correlates with vaccine response.

    Science.gov (United States)

    Wagar, Lisa E; Gentleman, Beth; Pircher, Hanspeter; McElhaney, Janet E; Watts, Tania H

    2011-01-01

    T cells specific for persistent pathogens accumulate with age and express markers of immune senescence. In contrast, much less is known about the state of T cell memory for acutely infecting pathogens. Here we examined T cell responses to influenza in human peripheral blood mononuclear cells from older (>64) and younger (<40) donors using whole virus restimulation with influenza A (A/PR8/34) ex vivo. Although most donors had pre-existing influenza reactive T cells as measured by IFNγ production, older donors had smaller populations of influenza-responsive T cells than young controls and had lost a significant proportion of their CD45RA-negative functional memory population. Despite this apparent dysfunction in a proportion of the older T cells, both old and young donors' T cells from 2008 could respond to A/California/07/2009 ex vivo. For HLA-A2+ donors, MHC tetramer staining showed that a higher proportion of influenza-specific memory CD8 T cells from the 65+ group co-express the markers killer cell lectin-like receptor G1 (KLRG1) and CD57 compared to their younger counterparts. These markers have previously been associated with a late differentiation state or immune senescence. Thus, memory CD8 T cells to an acutely infecting pathogen show signs of advanced differentiation and functional deterioration with age. There was a significant negative correlation between the frequency of KLRG1(+)CD57(+) influenza M1-specific CD8 T cells pre-vaccination and the ability to make antibodies in response to vaccination with seasonal trivalent inactivated vaccine, whereas no such trend was observed when the total CD8(+)KLRG1(+)CD57(+) population was analyzed. These results suggest that the state of the influenza-specific memory CD8 T cells may be a predictive indicator of a vaccine responsive healthy immune system in old age.

  5. Influenza-specific T cells from older people are enriched in the late effector subset and their presence inversely correlates with vaccine response.

    Directory of Open Access Journals (Sweden)

    Lisa E Wagar

    Full Text Available T cells specific for persistent pathogens accumulate with age and express markers of immune senescence. In contrast, much less is known about the state of T cell memory for acutely infecting pathogens. Here we examined T cell responses to influenza in human peripheral blood mononuclear cells from older (>64 and younger (<40 donors using whole virus restimulation with influenza A (A/PR8/34 ex vivo. Although most donors had pre-existing influenza reactive T cells as measured by IFNγ production, older donors had smaller populations of influenza-responsive T cells than young controls and had lost a significant proportion of their CD45RA-negative functional memory population. Despite this apparent dysfunction in a proportion of the older T cells, both old and young donors' T cells from 2008 could respond to A/California/07/2009 ex vivo. For HLA-A2+ donors, MHC tetramer staining showed that a higher proportion of influenza-specific memory CD8 T cells from the 65+ group co-express the markers killer cell lectin-like receptor G1 (KLRG1 and CD57 compared to their younger counterparts. These markers have previously been associated with a late differentiation state or immune senescence. Thus, memory CD8 T cells to an acutely infecting pathogen show signs of advanced differentiation and functional deterioration with age. There was a significant negative correlation between the frequency of KLRG1(+CD57(+ influenza M1-specific CD8 T cells pre-vaccination and the ability to make antibodies in response to vaccination with seasonal trivalent inactivated vaccine, whereas no such trend was observed when the total CD8(+KLRG1(+CD57(+ population was analyzed. These results suggest that the state of the influenza-specific memory CD8 T cells may be a predictive indicator of a vaccine responsive healthy immune system in old age.

  6. The ¿/d T-cell response to Plasmodium falciparum malaria in a population in which malaria is endemic

    DEFF Research Database (Denmark)

    Hviid, L; Kurtzhals, J A; Dodoo, D

    1996-01-01

    Frequencies and absolute numbers of peripheral gamma/delta T cells have been reported to increase after episodes of Plasmodium falciparum malaria in adults with limited or no previous malaria exposure. In contrast, little is known about the gamma/delta T-cell response to malaria in children from ...

  7. Critical role for CD1d-restricted invariant NKT cells in stimulating intrahepatic CD8 T-cell responses to liver antigen

    NARCIS (Netherlands)

    Sprengers, Dave; Sillé, Fenna C. M.; Derkow, Katja; Besra, Gurdyal S.; Janssen, Harry L. A.; Schott, Eckart; Boes, Marianne

    2008-01-01

    V alpha14 invariant natural killer T cells (iNKT) are localized in peripheral tissues such as the liver rather than lymphoid tissues. Therefore, their role in modulating the stimulation of conventional, major histocompatibility complex (MHC)-restricted T-cell responses has remained ambiguous. We

  8. Broadening CD4(+) and CD8(+) T Cell Responses against Hepatitis C Virus by Vaccination with NS3 Overlapping Peptide Panels in Cross-Priming Liposomes

    DEFF Research Database (Denmark)

    Filskov, Jonathan; Mikkelsen, Marianne; Hansen, Paul R.

    2017-01-01

    and was as potent a CD8+ T cell inducer as an adenovirus-vectored vaccine expressing NS3. Importantly, the cellular responses are dominated by multifunctional T cells, such as gamma interferon-positive (IFN-γ+) tumor necrosis factor alpha-positive (TNF-α+) coproducers, and displayed cytotoxic capacity in mice...

  9. Cryptococcosis-IRIS is Associated With Lower Cryptococcus-specific IFN-γ Responses Before Antiretroviral Therapy but Not Higher T-Cell Responses During Therapy

    Science.gov (United States)

    Chang, Christina C.; Lim, Andrew; Omarjee, Saleha; Levitz, Stuart M.; Gosnell, Bernadett I.; Spelman, Tim; Elliott, Julian H.; Carr, William H.; Moosa, Mohamed-Yunus S.; Ndung'u, Thumbi; Lewin, Sharon R.; French, Martyn A.

    2013-01-01

    Background. Cryptococcosis-associated immune reconstitution inflammatory syndrome (C-IRIS) may be driven by aberrant T-cell responses against cryptococci. We investigated this in human immunodeficiency virus (HIV)–infected patients with treated cryptococcal meningitis (CM) commencing combination antiretroviral therapy (cART). Methods. Mitogen- and cryptococcal mannoprotein (CMP)–activated (CD25+CD134+) CD4+ T cells and -induced production of interferon-gamma (IFN-γ), IL-10, and CXCL10 were assessed in whole blood cultures in a prospective study of 106 HIV–CM coinfected patients. Results. Patients with paradoxical C-IRIS (n = 27), compared with patients with no neurological deterioration (no ND; n = 63), had lower CMP-induced IFN-γ production in 24-hour cultures pre-cART and 4 weeks post-cART (P = .0437 and .0257, respectively) and lower CMP-activated CD4+ T-cell counts pre-cART (P = .0178). Patients surviving to 24 weeks had higher proportions of mitogen-activated CD4+ T cells and higher CMP-induced CXCL10 and IL-10 production in 24-hour cultures pre-cART than patients not surviving (P = .0053, .0436 and .0319, respectively). C-IRIS was not associated with higher CMP-specific T-cell responses before or during cART. Conclusion. Greater preservation of T-cell function and higher CMP-induced IL-10 and CXCL10 production before cART are associated with improved survival while on cART. Lower CMP-induced IFN-γ production pre-cART, but not higher CMP-specific T-cell responses after cART, were risk factors for C-IRIS. PMID:23766525

  10. Early growth response gene-2 (Egr-2 regulates the development of B and T cells.

    Directory of Open Access Journals (Sweden)

    Suling Li

    2011-04-01

    Full Text Available Understanding of how transcription factors are involved in lymphocyte development still remains a challenge. It has been shown that Egr-2 deficiency results in impaired NKT cell development and defective positive selection of T cells. Here we investigated the development of T, B and NKT cells in Egr-2 transgenic mice and the roles in the regulation of distinct stages of B and T cell development.The expression of Egr1, 2 and 3 were analysed at different stages of T and B cell development by RT-PCT and results showed that the expression was strictly regulated at different stages. Forced expression of Egr-2 in CD2(+ lymphocytes resulted in a severe reduction of CD4(+CD8(+ (DP cells in thymus and pro-B cells in bone marrow, which was associated with reduced expression of Notch1 in ISP thymocytes and Pax5 in pro-B cells, suggesting that retraction of Egr-2 at the ISP and pro-B cell stages is important for the activation of lineage differentiation programs. In contrast to reduction of DP and pro-B cells, Egr-2 enhanced the maturation of DP cells into single positive (SP T and NKT cells in thymus, and immature B cells into mature B cells in bone marrow.Our results demonstrate that Egr-2 expressed in restricted stages of lymphocyte development plays a dynamic, but similar role for the development of T, NKT and B cells.

  11. CD4 T cells mediate both positive and negative regulation of the immune response to HIV infection: complex role of T follicular helper cells and Regulatory T cells in pathogenesis

    Directory of Open Access Journals (Sweden)

    Chansavath ePhetsouphanh

    2015-01-01

    Full Text Available HIV-1 infection results in chronic activation of cells in lymphoid tissue, including T cells, B cells and myeloid lineage cells. The resulting characteristic hyperplasia is an amalgam of proliferating host immune cells in the adaptive response, increased concentrations of innate response mediators due to viral and bacterial products, and homeostatic responses to inflammation. While it is generally thought that CD4 T cells are greatly depleted, in fact, two types of CD4 T cells appear to be increased, namely regulatory T cells (Tregs and T follicular helper cells (Tfh. These cells have opposing roles, but may both be important in the pathogenic process. Whether Tregs are failing in their role to limit lymphocyte activation is unclear, but there is no doubt now that Tfh are associated with B cell hyperplasia and increased germinal centre activity. Antiretroviral therapy (ART may reduce the lymphocyte activation, but not completely, and therefore there is a need for interventions that selectively enhance normal CD4 function without exacerbating Tfh, B cell or Treg dysfunction.

  12. IL4I1: an inhibitor of the CD8⁺ antitumor T-cell response in vivo.

    Science.gov (United States)

    Lasoudris, Fanette; Cousin, Céline; Prevost-Blondel, Armelle; Martin-Garcia, Nadine; Abd-Alsamad, Issam; Ortonne, Nicolas; Farcet, Jean-Pierre; Castellano, Flavia; Molinier-Frenkel, Valérie

    2011-06-01

    The L-phenylalanine oxidase IL4I1 inhibits T-cell proliferation in vitro through H(2) O(2) production, and is highly expressed in tumor-associated macrophages. IL4I1 is also detected by immunohistochemistry in neoplastic cells from several B-cell lymphomas and some non-lymphoid tumors. To evaluate IL4I1's effect on tumor growth, we developed a mouse melanoma model constitutively coexpressing IL4I1 and the GP33 epitope. After GP33 vaccination, tumors developed more frequently in mice injected with IL4I1-expressing cells in comparison with mice receiving control cells. Tumor escape was preceded by a rapid diminution of IFN-γ-producing cytotoxic antitumor CD8(+) T cells. Moreover, tumor incidence was already increased when only 20% of the injected cells expressed IL4I1. The minimal IL4I1 activities leading to tumor escape were close to those detected in human melanoma and mesothelioma. Thus, we demonstrate the immunosuppressive functions of IL4I1 in vivo and suggest that IL4I1 facilitates human tumor growth by inhibiting the CD8(+) antitumor T-cell response. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. IL4I1: an inhibitor of the CD8(+) antitumor T-cell response in vivo

    Science.gov (United States)

    Lasoudris, Fanette; Cousin, Céline; Prevost-Blondel, Armelle; Martin-Garcia, Nadine; Abd-Alsamad, Issam; Ortonne, Nicolas; Farcet, Jean-Pierre; Castellano, Flavia; Molinier-Frenkel, Valérie

    2011-01-01

    The L-phenylalanine oxidase IL4I1 inhibits T-cell proliferation in vitro through H2O2 production, and is highly expressed in tumor-associated macrophages. IL4I1 is also detected by immunohistochemistry in neoplastic cells from several B-cell lymphomas and some non-lymphoid tumors. To evaluate IL4I1 effect on tumor growth, we developed a mouse melanoma model constitutively coexpressing IL4I1 and the GP33 epitope. After GP33 vaccination, tumors developed more frequently in mice injected with IL4I1-expressing cells in comparison to mice receiving control cells. Tumor escape was preceded by a rapid diminution of IFN-γ producing cytotoxic antitumor CD8+ T cells. Moreover, tumor incidence was already increased when only 20% of the injected cells expressed IL4I1. The minimal IL4I1 activities leading to tumor escape were close to those detected in human melanoma and mesothelioma. Thus, we demonstrate the immunosuppressive functions of IL4I1 in vivo and suggest that IL4I1 facilitates human tumor growth by inhibiting the CD8+ antitumor T-cell response. PMID:21469114

  14. Dichotomy of the human T cell response to Leishmania antigens. I. Th1-like response to Leishmania major promastigote antigens in individuals recovered from cutaneous leishmaniasis

    DEFF Research Database (Denmark)

    Kemp, M; Hey, A S; Kurtzhals, J A

    1994-01-01

    The T cell response to antigens from Leishmania major promastigotes was investigated in peripheral blood mononuclear cells from Sudanese individuals with a history of cutaneous leishmaniasis (CL), Sudanese individuals with positive DTH reaction in the leishmanin skin test but with no history of s...... or subclinical L. major infection is an IFN-gamma-producing Th1-like response....

  15. Hibernation is associated with depression of T-cell independent humoral immune responses in the 13-lined ground squirrel.

    Science.gov (United States)

    Bouma, Hjalmar R; Henning, Robert H; Kroese, Frans G M; Carey, Hannah V

    2013-03-01

    Mammalian hibernation consists of periods of low metabolism and body temperature (torpor), interspersed by euthermic arousal periods. The function of both the innate and adaptive immune system is suppressed during hibernation. In this study, we analyzed the humoral adaptive immune response to a T-cell independent (TI-2) and a T-cell dependent (TD) antigen. Thirteen-lined ground squirrels were immunized in summer or during hibernation with either a TI-2 or TD antigen on day 0 and day 14. Blood was drawn on day 0, 7, 14, 21 and 28. Both types of antigens induced a significant rise in antibody titer in summer animals. Much to our surprise, however, only immunization with the TD antigen, and not with the TI-2 antigen induced a humoral response in hibernators. Flow cytometric analysis of CD4 (helper T-lymphocytes), CD8 (cytotoxic T-lymphocytes) and CD45RA (B-lymphocytes) in blood, spleen and lymph nodes ruled out massive apoptosis as explanation of the absent TI humoral response during hibernation. Rather, reduced TI-2 stimulation of B-lymphocytes, possibly due to lowered serum complement during torpor, may explain the reduced antibody production in response to a TI-2 antigen. These results demonstrate that hibernation diminishes the capacity to induce a TI-2 humoral immune response, while the capacity to induce a humoral response to a TD antigen is maintained. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Cytotoxic T lymphocyte responses in allogeneic radiation bone marrow chimeras. The chimeric host strictly dictates the self-repertoire of Ia-restricted T cells but not H-2K/D-restricted T cells

    International Nuclear Information System (INIS)

    Bradley, S.M.; Kruisbeek, A.M.; Singer, A.

    1982-01-01

    The present report has used fully H-2 allogeneic radiation bone marrow chimeras to assess the role of host restriction elements in determining the self-specificity of Ia- and H-2K/D-restricted T cells that participate in the generation of trinitrophenyl (TNP)-specific cytotoxic T lymphocytes (CTL). It was demonstrated that there exists a stringent requirement for the recognition of host thymic-type Ia determinants, but there exists only a preference for host thymic-type H-2K/D determinants. Indeed, once the stringent requirement for recognition of host Ia determinants was fulfilled, anti-TNP CTL were generated in response to TNP-modified stimulators that expressed either donor-type or host-type H-2K/D determinants. The CTL that were generated in response to TNP-modified donor-type stimulators were shown to be specific for TNP and restricted to the non-thymic H-2K/D determinants of the chimeric donor. Thus, these results demonstrate in a single immune response that the thymic hypothesis accurately predicts the self-specificity expressed by Ia-restricted T cells, but does not fully account for the self-specificity expressed by H-2K/D-restricted T cells. These results are consistent with the concept that H-2K/D-restricted T cells, but not Ia-restricted T cells, can differentiate into functional competence either intrathymically or extra-thymically. The results demonstrate that the generation of anti-TNP CTL responses involve two parallel sets of major histocompatibility complex-restricted cell interactions, an Ia-restricted TH-accessory cell interaction required for TH cell activation, and an H-2K/D-restricted pCTL-stimulator cell interaction required for pCTL stimulation. The interaction between activated TH cells and stimulated pCTL is mediated, at least in part, by nonspecific soluble helper factors

  17. Low antigen dose formulated in CAF09 adjuvant Favours a cytotoxic T-cell response following intraperitoneal immunization in Göttingen minipigs

    DEFF Research Database (Denmark)

    Overgaard, Nana Haahr; Frøsig, Thomas Mørch; Jakobsen, Jeanne Toft

    2017-01-01

    in order to generate a certain type of immune response. To investigate this area further, we used Göttingen minipigs asan animal model especially due to the similar body size and high degree of immunome similarity between humans and pigs. In this study, we show that both a humoral and a cell......-dose immunization. Independent of antigen dose, intraperitoneal administration of antigen increased the amount of TT-specific cytotoxic CD8β+ T cells within the cytokine-producing T-cell pool when compared to the non-cytokine producing T-cell compartment. Taken together, these results demonstrate that a full...... protein formulated in the CAF09 adjuvant and administered to pigs via the intraperitoneal route effectively generates a cytotoxic T-cell response. Moreover, we confirm the inverse relationship between the antigen dose and the induction of polyfunctional T cells in a large animal model. These finding can...

  18. Generalized Liver- and Blood-Derived CD8+ T-Cell Impairment in Response to Cytokines in Chronic Hepatitis C Virus Infection.

    Directory of Open Access Journals (Sweden)

    Stephanie C Burke Schinkel

    Full Text Available Generalized CD8+ T-cell impairment in chronic hepatitis C virus (HCV infection and the contribution of liver-infiltrating CD8+ T-cells to the immunopathogenesis of this infection remain poorly understood. It is hypothesized that this impairment is partially due to reduced CD8+ T-cell activity in response to cytokines such as IL-7, particularly within the liver. To investigate this, the phenotype and cytokine responsiveness of blood- and liver-derived CD8+ T-cells from healthy controls and individuals with HCV infection were compared. In blood, IL-7 receptor α (CD127 expression on bulk CD8+ T-cells in HCV infection was no different than controls yet was lower on central memory T-cells, and there were fewer naïve cells. IL-7-induced signalling through phosphorylated STAT5 was lower in HCV infection than in controls, and differed between CD8+ T-cell subsets. Production of Bcl-2 following IL-7 stimulation was also lower in HCV infection and inversely related to the degree of liver fibrosis. In liver-derived CD8+ T-cells, STAT5 activation could not be increased with cytokine stimulation and basal Bcl-2 levels of liver-derived CD8+ T-cells were lower than blood-derived counterparts in HCV infection. Therefore, generalized CD8+ T-cell impairment in HCV infection is characterized, in part, by impaired IL-7-mediated signalling and survival, independent of CD127 expression. This impairment is more pronounced in the liver and may be associated with an increased potential for apoptosis. This generalized CD8+ T-cell impairment represents an important immune dysfunction in chronic HCV infection that may alter patient health.

  19. Vitamin D receptor signals regulate effector and memory CD8 T cell responses to infections in mice.

    Science.gov (United States)

    Yuzefpolskiy, Yevgeniy; Baumann, Florian M; Penny, Laura A; Studzinski, George P; Kalia, Vandana; Sarkar, Surojit

    2014-12-01

    Vitamin D insufficiency is associated with broad-ranging human disease sequelae such as bone disease, cancer, cardiovascular disease, allergy, autoimmune disorders, diabetes, and infectious diseases. Disease risk and severity of a large proportion of the nonskeletal disorders heavily involve the cytotoxic cluster of differentiation (CD) 8 T lymphocyte (CTL) arm of cellular adaptive immunity. Considering the importance of vitamin D in CTL-dependent diseases, there is a critical need for systematic in-depth explorations into the role of vitamin D deficiency in generation and maintenance of CTL immunity during infections and vaccinations. With the use of wild-type (WT) vitamin D-sufficient mice and the vitamin D receptor knockout (Vdr(-/-)) mouse model of in vivo deficiency of vitamin D signaling, we systematically analyzed the impact of vitamin D deficiency on antigen-specific effector and memory CD8 T cell responses to acute viral and bacterial infections. WT and Vdr(-/-) mice were infected with lymphocytic choriomeningitis virus, a natural mouse pathogen, and antigen-specific CTL responses were analyzed during priming, expansion, contraction, and memory phases. Magnitude, breadth, cytokine production, and localization of antiviral effector and memory CTLs to lymphoid and nonlymphoid tissues were specifically assessed. The absence of vitamin D signals led to 1) aberrant CD8 T cell effector differentiation (∼2-fold lower granzyme B and reduced B cell lymphoma 2; P ≤ 0.05) and enhanced contraction (∼15% increase; P ≤ 0.05) in antigen-specific CTLs; 2) a significantly restricted (P ≤ 0.05) breadth of the antigen-specific CD8 T cell effector and memory repertoire; and 3) preferential localization of effector (∼2.5-fold increase; P ≤ 0.01) and memory (∼5-fold increase; P ≤ 0.001) CD8 T cells to the lymph nodes compared to nonlymphoid tissues. Our data show a previously unrecognized impact of vitamin D deficiency on the quantity, quality, breadth, and

  20. Global Assessment of Dengue Virus-Specific CD4+ T Cell Responses in Dengue-Endemic Areas

    Directory of Open Access Journals (Sweden)

    Alba Grifoni

    2017-10-01

    Full Text Available BackgroundDengue is a major public health problem worldwide. Assessment of adaptive immunity is important to understanding immunopathology and to define correlates of protection against dengue virus (DENV. To enable global assessment of CD4+ T cell responses, we mapped HLA-DRB1-restricted DENV-specific CD4+ T cell epitopes in individuals previously exposed to DENV in the general population of the dengue-endemic region of Managua, Nicaragua.MethodsHLA class II epitopes in the population of Managua were identified by an in vitro IFNγ ELISPOT assay. CD4+ T cells purified by magnetic bead negative selection were stimulated with HLA-matched epitope pools in the presence of autologous antigen-presenting cells, followed by pool deconvolution to identify specific epitopes. The epitopes identified in this study were combined with those previously identified in the DENV endemic region of Sri Lanka, to generate a “megapool” (MP consisting of 180 peptides specifically designed to achieve balanced HLA and DENV serotype coverage. The DENV CD4MP180 was validated by intracellular cytokine staining assays.ResultsWe detected responses directed against a total of 431 epitopes, representing all 4 DENV serotypes, restricted by 15 different HLA-DRB1 alleles. The responses were associated with a similar pattern of protein immunodominance, overall higher magnitude of responses, as compared to what was observed previously in the Sri Lanka region. Based on these epitope mapping studies, we designed a DENV CD4 MP180 with higher and more consistent coverage, which allowed the detection of CD4+ T cell DENV responses ex vivo in various cohorts of DENV exposed donors worldwide, including donors from Nicaragua, Brazil, Singapore, Sri Lanka, and U.S. domestic flavivirus-naïve subjects immunized with Tetravalent Dengue Live-Attenuated Vaccine (TV005. This broad reactivity reflects that the 21 HLA-DRB1 alleles analyzed in this and previous studies account for more than 80

  1. Characterization of T-cell responses against IκBα in cancer patients

    DEFF Research Database (Denmark)

    Munir, Shamaila; Frøsig, Thomas Mørch; Hansen, Morten

    2012-01-01

    The nuclear factor κ light chain enhancer of activated B cells (NFκB) is constitutively active in most cancers, controlling multiple cellular processes including proliferation, invasion and resistance to therapy. NFκB is primarily regulated through the association with inhibitory proteins...... that are known as inhibitors of NFκB (IκBs). Increased NFκB activity in tumor cells h