scholarly journals CD8+ T-cell recognition of human cytomegalovirus latency-associated determinant pUL138

2010 ◽  
Vol 91 (8) ◽  
pp. 2040-2048 ◽  
Author(s):  
Siok-Keen Tey ◽  
Felicia Goodrum ◽  
Rajiv Khanna
Keyword(s):  
T Cells ◽  
T Cell ◽  
Human Cytomegalovirus ◽  
Cell Response ◽  
Hcmv Infection ◽  
Mononuclear Cells ◽  
T Cell Response ◽  
Cell Recognition ◽  
T Cell Recognition ◽  
Infected Cells

Recent studies have shown that long-term persistence of human cytomegalovirus (HCMV) in mononuclear cells of myeloid lineage is dependent on the UL138 open reading frame, which promotes latent infection. Although T-cell recognition of protein antigens from all stages of lytic HCMV infection is well established, it is not clear whether proteins expressed during latent HCMV infection can also be recognized. This study conducted an analysis of T-cell response towards proteins associated with HCMV latency. Ex vivo analysis of T cells from healthy virus carriers revealed a dominant CD8+ T-cell response to the latency-associated pUL138 protein, which recognized a non-canonical 13 aa epitope in association with HLA-B*3501. These pUL138-specific T cells displayed a range of memory phenotypes that were in general less differentiated than that previously described in T cells specific for HCMV lytic antigens. Antigen-presentation assays revealed that endogenous pUL138 could be presented efficiently by HCMV-infected cells. However, T-cell recognition of pUL138 was dependent on newly synthesized protein, with little presentation from stable, long-lived protein. These data demonstrate that T cells targeting latency-associated protein products exist, although HCMV may limit the presentation of latent proteins, thereby restricting T-cell recognition of latently infected cells.

scholarly journals Human Cytomegalovirus (HCMV)-Specific CD4+ T Cells Are Polyfunctional and Can Respond to HCMV-Infected Dendritic Cells In Vitro

2017 ◽  
Vol 91 (6) ◽  
Author(s):  
Sarah E. Jackson ◽  
George X. Sedikides ◽  
Gavin M. Mason ◽  
Georgina Okecha ◽  
Mark R. Wills
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Human Cytomegalovirus ◽  
Immune Cells ◽  
Cell Response ◽  
T Cell Response ◽  
Cell Responses ◽  
Infected Cells

ABSTRACT Human cytomegalovirus (HCMV) infection and periodic reactivation are generally well controlled by the HCMV-specific T cell response in healthy people. While the CD8+ T cell response to HCMV has been extensively studied, the HCMV-specific CD4+ T cell effector response is not as well understood, especially in the context of direct interactions with HCMV-infected cells. We screened the gamma interferon (IFN-γ) and interleukin-10 (IL-10) responses to 6 HCMV peptide pools (pp65, pp71, IE1, IE2, gB, and US3, selected because they were the peptides most frequently responded to in our previous studies) in 84 donors aged 23 to 74 years. The HCMV-specific CD4+ T cell response to pp65, IE1, IE2, and gB was predominantly Th1 biased, with neither the loss nor the accumulation of these responses occurring with increasing age. A larger proportion of donors produced an IL-10 response to pp71 and US3, but the IFN-γ response was still dominant. CD4+ T cells specific to the HCMV proteins studied were predominantly effector memory cells and produced both cytotoxic (CD107a expression) and cytokine (macrophage inflammatory protein 1β secretion) effector responses. Importantly, when we measured the CD4+ T cell response to cytomegalovirus (CMV)-infected dendritic cells in vitro, we observed that the CD4+ T cells produced a range of cytotoxic and secretory effector functions, despite the presence of CMV-encoded immune evasion molecules. CD4+ T cell responses to HCMV-infected dendritic cells were sufficient to control the dissemination of virus in an in vitro assay. Together, the results show that HCMV-specific CD4+ T cell responses, even those from elderly individuals, are highly functional and are directly antiviral. IMPORTANCE Human cytomegalovirus (HCMV) infection is carried for a lifetime and in healthy people is kept under control by the immune system. HCMV has evolved many mechanisms to evade the immune response, possibly explaining why the virus is never eliminated during the host's lifetime. The dysfunction of immune cells associated with the long-term carriage of HCMV has been linked with poor responses to new pathogens and vaccines when people are older. In this study, we investigated the response of a subset of immune cells (CD4+ T cells) to HCMV proteins in healthy donors of all ages, and we demonstrate that the functionality of CD4+ T cells is maintained. We also show that CD4+ T cells produce effector functions in response to HCMV-infected cells and can prevent virus spread. Our work demonstrates that these HCMV-specific immune cells retain many important functions and help to prevent deleterious HCMV disease in healthy older people.

scholarly journals Target Structures of the CD8+-T-Cell Response to Human Cytomegalovirus: the 72-Kilodalton Major Immediate-Early Protein Revisited

1999 ◽  
Vol 73 (10) ◽  
pp. 8179-8184 ◽  
Author(s):  
Florian Kern ◽  
Ingolf Pascal Surel ◽  
Nicole Faulhaber ◽  
Claudia Frömmel ◽  
Jens Schneider-Mergener ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Human Cytomegalovirus ◽  
Cell Response ◽  
Mononuclear Cells ◽  
T Cell Response ◽  
Immediate Early ◽  
Cell Mediated Immunity ◽  
T Cell Epitopes ◽  
Early Protein

ABSTRACT Cell-mediated immunity plays an essential role in the control of infection with the human cytomegalovirus (HCMV). However, only a few CD8+-T-cell epitopes are known, with the majority being contained in the pp65 phosphoprotein, which is believed to dominate the CD8+-T-cell response to HCMV. Here, we have readdressed the issue of CD8+ T cells specific for the 72-kDa major immediate-early protein (IE-1), which is nonstructural but is found very early and throughout the replicative cycle. Using a novel flow-cytometric assay, we were able to identify CD8+-T-cell epitopes (by IE-1 peptide-specific induction of cytokine synthesis) and simultaneously measure the frequency of cells directed against them. For this purpose, 81 pentadecamer peptides covering the complete 491-amino-acid sequence of IE-1 were tested on peripheral blood mononuclear cells of anti-HCMV immunoglobulin G-seropositive donors. At least 10 new epitopes were identified, and the fine specificity and presenting HLA molecule of the first of them was determined. The frequencies of CD8+ T cells directed against IE-1 were similar to those directed against pp65 in donors tested with known pp65-derived peptides. Importantly, additional testing of a corresponding set of peptides covering the complete sequence of pp65 on 10 of these donors identified individuals whose CD8+ T cells recognized IE-1 but not pp65 and vice versa, clearly illustrating that either protein may be a major target. In summary, our results suggest that IE-1 is far more important as a CD8+-T-cell target than current opinion suggests.

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

2010 ◽  
Vol 84 (20) ◽  
pp. 10543-10557 ◽  
Author(s):  
Rebecca P. Payne ◽  
Henrik Kløverpris ◽  
Jonah B. Sacha ◽  
Zabrina Brumme ◽  
Chanson Brumme ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mononuclear Cells ◽  
T Cell Response ◽  
Viral Escape ◽  
Specific Response ◽  
Immune Control ◽  
Antiviral Efficacy ◽  
Infected Cells ◽  
Hiv 1

ABSTRACT The association between HLA-B*2705 and the immune control of human immunodeficiency virus type 1 (HIV-1) has previously been linked to the targeting of the HLA-B*2705-restricted Gag epitope KRWIILGLNK (KK10) by CD8+ T cells. In order to better define the mechanisms of the HLA-B*2705 immune control of HIV, we first characterized the CD8+ T-cell responses of nine highly active antiretroviral therapy (HAART)-naïve B*2705-positive subjects. Unexpectedly, we observed a strong response to an HLA-B*2705-restricted Pol epitope, KRKGGIGGY (KY9), in 8/9 subjects. The magnitude of the KY9 response was only marginally lower than that of the KK10-specific response (median, 695 versus 867 spot-forming cells [SFC]/million peripheral blood mononuclear cells [PBMCs]; not significant [NS]), and viral escape mutants were observed in both KY9 and KK10, resulting from selection pressure driven by the respective CD8+ T-cell response. By comparing inhibitions of viral replication by CD8+ T cells specific for the Gag KK10, Pol KY9, and Vpr VL9 HLA-B*2705-restricted epitopes, we observed a consistent hierarchy of antiviral efficacy (Gag KK10 > Pol KY9 > Vpr VL9). This hierarchy was associated with early recognition of HIV-1-infected cells, within 6 h of infection, by KK10- and KY9-specific CD8+ T cells but not until 18 h postinfection by VL9-specific CD8+ T cells. There was no association between antiviral efficacy and proliferative capacity, cytotoxicity, polyfunctionality, or T-cell receptor (TCR) avidity. These data are consistent with previous studies indicating an important role for the B*2705-Gag KK10 response in the control of HIV but also suggest a previously unrecognized role played by the subdominant Pol-specific KY9 response in HLA-B*2705-mediated control of HIV and that the recognition of HIV-infected cells by CD8+ T cells early in the viral life cycle may be important for viral containment in HIV-infected individuals.

scholarly journals Primary HIV-1 Strains Use Nef To Downmodulate HLA-E Surface Expression

2019 ◽  
Vol 93 (20) ◽  
Author(s):  
Thomas van Stigt Thans ◽  
Janet I. Akko ◽  
Annika Niehrs ◽  
Wilfredo F. Garcia-Beltran ◽  
Laura Richert ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Line ◽  
Nk Cell ◽  
Cytoplasmic Tail ◽  
Cytotoxic T Cell ◽  
Cell Recognition ◽  
T Cell Recognition ◽  
Infected Cells ◽  
Hiv 1

ABSTRACTHuman immunodeficiency virus type 1 (HIV-1) has evolved elaborate ways to evade immune cell recognition, including downregulation of classical HLA class I (HLA-I) from the surfaces of infected cells. Recent evidence identified HLA-E, a nonclassical HLA-I, as an important part of the antiviral immune response to HIV-1. Changes in HLA-E surface levels and peptide presentation can prompt both CD8+T-cell and natural killer (NK) cell responses to viral infections. Previous studies reported unchanged or increased HLA-E levels on HIV-1-infected cells. Here, we examined HLA-E surface levels following infection of CD4+T cells with primary HIV-1 strains and observed that a subset downregulated HLA-E. Two primary strains of HIV-1 that induced the strongest reduction in surface HLA-E expression were chosen for further testing. Expression of single Nef or Vpu proteins in a T-cell line, as well as tail swap experiments exchanging the cytoplasmic tail of HLA-A2 with that of HLA-E, demonstrated that Nef modulated HLA-E surface levels and targeted the cytoplasmic tail of HLA-E. Furthermore, infection of primary CD4+T cells with HIV-1 mutants showed that a lack of functional Nef (and Vpu to some extent) impaired HLA-E downmodulation. Taken together, the results of this study demonstrate for the first time that HIV-1 can downregulate HLA-E surface levels on infected primary CD4+T cells, potentially rendering them less vulnerable to CD8+T-cell recognition but at increased risk of NKG2A+NK cell killing.IMPORTANCEFor almost two decades, it was thought that HIV-1 selectively downregulated the highly expressed HLA-I molecules HLA-A and HLA-B from the cell surface in order to evade cytotoxic-T-cell recognition, while leaving HLA-C and HLA-E molecules unaltered. It was stipulated that HIV-1 infection thereby maintained inhibition of NK cells via inhibitory receptors that bind HLA-C and HLA-E. This concept was recently revised when a study showed that primary HIV-1 strains reduce HLA-C surface levels, whereas the cell line-adapted HIV-1 strain NL4-3 lacks this ability. Here, we demonstrate that infection with distinct primary HIV-1 strains results in significant downregulation of surface HLA-E levels. Given the increasing evidence for HLA-E as an important modulator of CD8+T-cell and NKG2A+NK cell functions, this finding has substantial implications for future immunomodulatory approaches aimed at harnessing cytotoxic cellular immunity against HIV.

scholarly journals Targeting Human-Cytomegalovirus-Infected Cells by Redirecting T Cells Using an Anti-CD3/Anti-Glycoprotein B Bispecific Antibody

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Weixu Meng ◽  
Aimin Tang ◽  
Xiaohua Ye ◽  
Xun Gui ◽  
Leike Li ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Human Cytomegalovirus ◽  
T Cell Activation ◽  
Cell Activation ◽  
Bispecific Antibody ◽  
Hcmv Infection ◽  
Glycoprotein B ◽  
Transplant Recipients ◽  
Infected Cells

ABSTRACTThe host immune response to human cytomegalovirus (HCMV) is effective against HCMV reactivation from latency, though not sufficient to clear the virus. T cells are primarily responsible for the control of viral reactivation. When the host immune system is compromised, as in transplant recipients with immunosuppression, HCMV reactivation and progressive infection can cause serious morbidity and mortality. Adoptive T cell therapy is effective for the control of HCMV infection in transplant recipients. However, it is a highly personalized therapeutic regimen and is difficult to implement in routine clinical practice. In this study, we explored a bispecific-antibody strategy to direct non-HCMV-specific T cells to recognize and exert effector functions against HCMV-infected cells. Using a knobs-into-holes strategy, we constructed a bispecific antibody in which one arm is specific for CD3 and can trigger T cell activation, while the other arm, specific for HCMV glycoprotein B (gB), recognizes and marks HCMV-infected cells based on the expression of viral gB on their surfaces. We showed that this bispecific antibody was able to redirect T cells with specificity for HCMV-infected cellsin vitro. In the presence of HCMV infection, the engineered antibody was able to activate T cells with no HCMV specificity for cytokine production, proliferation, and the expression of phenotype markers unique to T cell activation. These results suggested the potential of engineered bispecific antibodies, such as the construct described here, as prophylactic or therapeutic agents against HCMV reactivation and infection.

Adjuvant Immunization of HLA-A2–Positive Melanoma Patients With a Modified gp100 Peptide Induces Peptide-Specific CD8+ T-Cell Responses

2003 ◽  
Vol 21 (8) ◽  
pp. 1562-1573 ◽  
Author(s):  
John W. Smith ◽  
Edwin B. Walker ◽  
Bernard A. Fox ◽  
Daniel Haley ◽  
Ketura P. Wisner ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Response ◽  
Mononuclear Cells ◽  
Peptide Vaccine ◽  
Flow Cytometric Analysis ◽  
T Cell Response ◽  
Median Frequency ◽  
Peripheral Blood Mononuclear ◽  
Tetramer Binding

Purpose: To measure the CD8+ T-cell response to a melanoma peptide vaccine and to compare an every-2-weeks with an every-3-weeks vaccination schedule. Patients and Methods: Thirty HLA-A2–positive patients with resected stage I to III melanoma were randomly assigned to receive vaccinations every 2 weeks (13 vaccines) or every 3 weeks (nine vaccines) for 6 months. The synthetic, modified gp100 peptide, g209–2M, and a control peptide, HPV16 E7, were mixed in incomplete Freund’s adjuvant and injected subcutaneously. Peripheral blood mononuclear cells obtained before and after vaccination by leukapheresis were analyzed using a fluorescence-based HLA/peptide-tetramer binding assay and cytokine flow cytometry. Results: Vaccination induced an increase in peptide-specific T cells in 28 of 29 patients. The median frequency of CD8+ T cells specific for the g209–2M peptide increased markedly from 0.02% before to 0.34% after vaccination (P < .0001). Eight patients (28%) exhibited peptide-specific CD8+ T-cell frequencies greater than 1%, including two patients with frequencies of 4.96% and 8.86%, respectively. Interferon alfa-2b–treated patients also had significant increases in tetramer-binding cells (P < .0001). No difference was observed between the every-2-weeks and the every-3-weeks vaccination schedules (P = .59). Conclusion: Flow cytometric analysis of HLA/peptide-tetramer binding cells was a reliable means of quantifying the CD8+ T-cell response to peptide immunization. This assay may be suitable for use in future trials to optimize different vaccination strategies. Concurrent interferon treatment did not inhibit the development of a peptide-specific immune response and vaccination every 2 weeks, and every 3 weeks produced similar results.

Sign in / Sign up

Export Citation Format

Share Document