scholarly journals IL-10 blockade facilitates DNA vaccine-induced T cell responses and enhances clearance of persistent virus infection

2008 ◽  
Vol 205 (3) ◽  
pp. 533-541 ◽  
Author(s):  
David G. Brooks ◽  
Andrew M. Lee ◽  
Heidi Elsaesser ◽  
Dorian B. McGavern ◽  
Michael B.A. Oldstone
Keyword(s):  
T Cell ◽  
Viral Infection ◽  
Dna Vaccine ◽  
Viral Infections ◽  
T Cell Responses ◽  
Lymphocytic Choriomeningitis ◽  
T Cell Immunity ◽  
Therapeutic Vaccination ◽  
Cell Responses ◽  
Cell Immunity

Therapeutic vaccination is a potentially powerful strategy to establish immune control and eradicate persistent viral infections. Large and multifunctional antiviral T cell responses are associated with control of viral persistence; however, for reasons that were mostly unclear, current therapeutic vaccination approaches to restore T cell immunity and control viral infection have been ineffective. Herein, we confirmed that neutralization of the immunosuppressive factor interleukin (IL)-10 stimulated T cell responses and improved control of established persistent lymphocytic choriomeningitis virus (LCMV) infection. Importantly, blockade of IL-10 also allowed an otherwise ineffective therapeutic DNA vaccine to further stimulate antiviral immunity, thereby increasing T cell responses and enhancing clearance of persistent LCMV replication. We therefore propose that a reason that current therapeutic vaccination strategies fail to resurrect/sustain T cell responses is because they do not alleviate the immunosuppressive environment. Consequently, blocking key suppressive factors could render ineffective vaccines more efficient at improving T cell immunity, and thereby allow immune-mediated control of persistent viral infection.

scholarly journals A Combination of Anti-PD-L1 Treatment and Therapeutic Vaccination Facilitates Improved Retroviral Clearance via Reactivation of Highly Exhausted T Cells

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Torben Knuschke ◽  
Sebastian Kollenda ◽  
Christina Wenzek ◽  
Gennadiy Zelinskyy ◽  
Philine Steinbach ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Combination Therapy ◽  
Viral Infection ◽  
Viral Infections ◽  
T Cell Immunity ◽  
Chronic Viral Infection ◽  
Therapeutic Vaccination ◽  
Chronic Viral Infections ◽  
Cell Immunity

ABSTRACT PD-1-targeted therapies have shown modest antiviral effects in preclinical models of chronic viral infection. Thus, novel therapy protocols are necessary to enhance T cell immunity and viral control to overcome T cell dysfunction and immunosuppression. Here, we demonstrate that nanoparticle-based therapeutic vaccination improved PD-1-targeted therapy during chronic infection with Friend retrovirus (FV). Prevention of inhibitory signals by blocking PD-L1 in combination with therapeutic vaccination with nanoparticles containing the microbial compound CpG and a CD8+ T cell Gag epitope peptide synergistically enhanced functional virus-specific CD8+ T cell responses and improved viral clearance. We characterized the CD8+ T cell populations that were affected by this combination therapy, demonstrating that new effector cells were generated and that exhausted CD8+ T cells were reactivated at the same time. While CD8+ T cells with high PD-1 (PD-1hi) expression turned into a large population of granzyme B-expressing CD8+ T cells after combination therapy, CXCR5-expressing follicular cytotoxic CD8+ T cells also expanded to a high degree. Thus, our study describes a very efficient approach to enhance virus control and may help us to understand the mechanisms of combination immunotherapy reactivating CD8+ T cell immunity. A better understanding of CD8+ T cell immunity during combination therapy will be important for developing efficient checkpoint therapies against chronic viral infections and cancer. IMPORTANCE Despite significant efforts, vaccines are not yet available for every infectious pathogen, and the search for a protective approach to prevent the establishment of chronic infections, i.e., with HIV, continues. Immune checkpoint therapies targeting inhibitory receptors, such as PD-1, have shown impressive results against solid tumors. However, immune checkpoint therapies have not yet been licensed to treat chronic viral infections, since a blockade of inhibitory receptors alone provides only limited benefit, as demonstrated in preclinical models of chronic viral infection. Thus, there is a high interest in the development of potent combination immunotherapies. Here, we tested whether the combination of a PD-L1 blockade and therapeutic vaccination with functionalized nanoparticles is a potent therapy during chronic Friend retrovirus infection. We demonstrate that the combination therapy induced a synergistic reinvigoration of the exhausted virus-specific CD8+ T cell immunity. Taken together, our results provide further information on how to improve PD-1-targeted therapies during chronic viral infection and cancer.

scholarly journals Enhancing therapeutic vaccination by blocking PD-1–mediated inhibitory signals during chronic infection

2008 ◽  
Vol 205 (3) ◽  
pp. 543-555 ◽  
Author(s):  
Sang-Jun Ha ◽  
Scott N. Mueller ◽  
E. John Wherry ◽  
Daniel L. Barber ◽  
Rachael D. Aubert ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Treatment Strategies ◽  
T Cell Responses ◽  
Lymphocytic Choriomeningitis ◽  
Therapeutic Vaccination ◽  
Chronic Infections ◽  
Viral Control ◽  
Cell Responses ◽  
Cell Immunity

Therapeutic vaccination is a potentially promising strategy to enhance T cell immunity and viral control in chronically infected individuals. However, therapeutic vaccination approaches have fallen short of expectations, and effective boosting of antiviral T cell responses has not always been observed. One of the principal reasons for the limited success of therapeutic vaccination is that virus-specific T cells become functionally exhausted during chronic infections. We now provide a novel strategy for enhancing the efficacy of therapeutic vaccines. In this study, we show that blocking programmed death (PD)-1/PD-L1 inhibitory signals on exhausted CD8+ T cells, in combination with therapeutic vaccination, synergistically enhances functional CD8+ T cell responses and improves viral control in mice chronically infected with lymphocytic choriomeningitis virus. This combinatorial therapeutic vaccination was effective even in the absence of CD4+ T cell help. Thus, our study defines a potent new approach to augment the efficacy of therapeutic vaccination by blocking negative signals. Such an approach may have broad applications in developing treatment strategies for chronic infections in general, and perhaps also for tumors.

scholarly journals Protection from viral rebound after therapeutic vaccination with an adjuvanted DNA vaccine is associated with SIV-specific polyfunctional CD8 T cells in the blood and mesenteric lymph nodes

2020 ◽  
Author(s):  
Hillary C. Tunggal ◽  
Paul V. Munson ◽  
Megan A. O’Connor ◽  
Nika Hajari ◽  
Sandra E. Dross ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Dna Vaccine ◽  
Therapeutic Vaccine ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Viral Rebound ◽  
Cell Responses ◽  
Cell Immunity

AbstractA therapeutic vaccine that induces lasting control of HIV infection has the potential to eliminate the need for lifelong adherence to antiretroviral therapy (ART). This study investigated the efficacy of a therapeutic DNA vaccine delivered with a novel combination of adjuvants and immunomodulators to augment T cell immunity in the blood and gut-associated lymphoid tissue. In SIV-infected rhesus macaques, a DNA vaccine delivered by intradermal electroporation and expressing SIV Env, Gag, and Pol, and a combination of adjuvant plasmids expressing the catalytic A1 subunit of E. coli heat labile enterotoxin (LTA1), IL-12, IL-33, retinaldehyde dehydrogenase 2 and the immunomodulators soluble PD-1 and soluble CD80, significantly enhanced the breadth and magnitude of Gag-specific IFN-γ T cell responses when compared to controls that were mock vaccinated or received the same DNA vaccine delivered by Gene Gun with a single adjuvant, the E. coli heat labile enterotoxin, LT. Notably, the DNA vaccine and adjuvant combination protected 3/5 animals from viral rebound, compared to only 1/4 mock vaccinated animals and 1/5 animals that received the DNA vaccine and LT. The lower viral burden among controllers during analytical treatment interruption significantly correlated with higher polyfunctional CD8+ T-cells (CD8+ T cells expressing 3 or more effector functions) in both mesenteric lymph nodes and blood measured during ART and analytical treatment interruption. Interestingly, controllers also had lower viral loads during acute infection and ART suggesting that inherent host-viral interactions induced prior to ART initiation likely influenced the response to therapeutic vaccination. These data indicate that gut mucosal immune responses combined with effective ART may play a key role in containing residual virus post-ART and highlight the need for therapeutic vaccines and adjuvants that can restore functional quality of peripheral and mucosal T cell responses before and during ART.Author SummaryHIV has caused significant human disease and mortality since its emergence in the 1980s. Furthermore, although antiretroviral therapy (ART) effectively reduces viral replication, stopping ART leads to increased viral loads and disease progression in most HIV-infected people. A therapeutic vaccine could enable HIV-infected people to control their infection without ART, but none of the vaccines that were tested in clinical trials so far have induced long-lasting control of virus replication. Here, we used the SIV rhesus macaque model to test a therapeutic vaccine consisting of DNA expressing SIV proteins and a novel combination of adjuvants to boost virus-specific immune responses. We found that our vaccine strategy significantly enhanced SIV-specific T cell responses when compared to controls and protected 3/5 animals from viral rebound. We determined that lower levels of virus replication post-ART were associated with enhanced T cell immunity in the gut-draining lymph nodes and blood. Our study highlights the critical role of T cell immunity for control of SIV and HIV replication and demonstrates that a successful therapeutic vaccine for HIV will need to elicit potent T cell responses in both the blood and gut-associated tissues.

538 Harnessing cross-dressing dendritic cells to strengthen anti-tumor immunity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A574-A574
Author(s):  
Ellen Duong ◽  
Timothy Fessenden ◽  
Arjun Bhutkar ◽  
Stefani Spranger
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cancer Cell ◽  
Tumor Immunity ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Cell Responses ◽  
Cell Immunity ◽  
Cross Dressing

BackgroundCytotoxic (CD8+) T-cells are required for tumor eradication and durable anti-tumor immunity.1 The induction of tumor-reactive CD8+ T-cells is predominately attributed to a subset of dendritic cells (DC) called Batf3-driven DC1, given their robust ability to cross-present antigens for T-cell priming and their role in effector T-cell recruitment.2–4 Presence of the DC1 signature in tumors correlates with improved survival and response to immunotherapies.5–7 Yet, most tumors with a DC1 infiltrate still progress, suggesting that while DC1 can initiate tumor-reactive CD8+ T-cell responses, they are unable to sustain them. Therefore, there is a critical need to identify and engage additional stimulatory DC subsets to strengthen anti-tumor immunity and boost immunotherapy responses.MethodsTo identify DC subsets that drive poly-functional CD8+ T-cell responses, we compared the DC infiltrate of a spontaneously regressing tumor with a progressing tumor. Multicolor flow immunophenotyping and single-cell RNA-sequencing were used to profile the DC compartment of both tumors. IFNγ-ELISpot was performed on splenocytes to assess for systemic tumor-reactive T-cell responses. Sorted DC subsets from tumors were co-cultured with TCR-transgenic T-cells ex vivo to evaluate their stimulatory capacity. Cross-dressing (in vivo/ex vivo) was assayed by staining for transfer of tumor-derived H-2b MHC complexes to Balb/c DC, which express the H-2d haplotype. Protective systemic immunity was assayed via contralateral flank tumor outgrowth experiments.ResultsRegressor tumors were infiltrated with more cross-presenting DC1 than progressor tumors. However, tumor-reactive CD8+ T-cell responses and tumor control were preserved in Batf3-/- mice lacking DC1, indicating that anti-tumor immune responses could be induced independent of DC1. Through functional assays, we established that anti-tumor immunity against regressor tumors required CD11c+ DC and cGAS/STING-independent type-I-interferon-sensing. Single-cell RNA-sequencing of the immune infiltrate of regressor tumors revealed a novel CD11b+ DC subset expressing an interferon-stimulated gene signature (ISG+ DC). Flow studies demonstrated that ISG+ DC were more enriched in regressor tumors than progressor tumors. We showed that ISG+ DC could activate CD8+ T-cells by cross-dressing with tumor-derived peptide-MHC complexes, thereby bypassing the requirement for cross-presentation to initiate CD8+ T-cell-driven immunity. ISG+ DC highly expressed cytosolic dsRNA sensors (RIG-I/MDA5) and could be therapeutically harnessed by exogenous addition of a dsRNA analog to drive protective CD8+ T-cell responses in DC1-deficient mice.ConclusionsThe DC infiltrate in tumors can dictate the strength of anti-tumor immunity. Harnessing multiple stimulatory DC subsets, such as cross-presenting DC1 and cross-dressing ISG+ DC, provides a therapeutic opportunity to enhance anti-tumor immunity and increase immunotherapy responses.ReferencesFridman WH, et al. The immune contexture in human tumours: impact on clinical outcome. Nature Reviews Cancer 2012;12(4): p. 298–306.Hildner K, et al. Batf3 deficiency reveals a critical role for CD8alpha+ dendritic cells in cytotoxic T cell immunity. Science 2008;322(5904):p. 1097–100.Spranger S, et al. Tumor-Residing Batf3 dendritic cells are required for effector T cell trafficking and adoptive T cell therapy. Cancer Cell 2017;31(5):p. 711–723.e4.Roberts, EW, et al., Critical role for CD103(+)/CD141(+) dendritic cells bearing CCR7 for tumor antigen trafficking and priming of T cell immunity in melanoma. Cancer Cell 2016;30(2): p. 324–336.Broz ML, et al. Dissecting the tumor myeloid compartment reveals rare activating antigen-presenting cells critical for T cell immunity. Cancer Cell 2014;26(5): p. 638–52.Salmon H., et al., Expansion and activation of CD103(+) dendritic cell progenitors at the tumor site enhances tumor responses to therapeutic PD-L1 and BRAF inhibition. Immunity, 2016. 44(4): p. 924–38.Sánchez-Paulete AR, et al., Cancer immunotherapy with immunomodulatory anti-CD137 and Anti-PD-1 monoclonal antibodies requires BATF3-dependent dendritic cells. Cancer Discov, 2016;6(1):p. 71–9.

CpG pretreatment enhances antiviral T-cell immunity against cytomegalovirus

Blood ◽  
2013 ◽  
Vol 122 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Monique L. Ong ◽  
Matthew E. Wikstrom ◽  
Peter Fleming ◽  
Marie J. Estcourt ◽  
Paul J. Hertzog ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Viral Proteins ◽  
T Cell Immunity ◽  
Cross Presentation ◽  
Cell Responses ◽  
Cell Immunity ◽  
Key Points

Key Points Fully functional CD8 T-cell responses, control of infection, and protection from organ pathology are attained without cross-presentation. Direct presentation generates responses that limit disease and ensure host survival despite the presence of immunomodulatory viral proteins.

scholarly journals HCoV- and SARS-CoV-2 Cross-Reactive T Cells in CVID Patients

2020 ◽  
Vol 11 ◽  
Author(s):  
Sophie Steiner ◽  
Franziska Sotzny ◽  
Sandra Bauer ◽  
Il-Kang Na ◽  
Michael Schmueck-Henneresse ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Cross Reactivity ◽  
T Cell Immunity ◽  
Cell Reactivity ◽  
Cd8 Cells ◽  
Cell Responses ◽  
Cell Immunity

The inability of patients with CVID to mount specific antibody responses to pathogens has raised concerns on the risk and severity of SARS-CoV-2 infection, but there might be a role for protective T cells in these patients. SARS-CoV-2 reactive T cells have been reported for SARS-CoV-2 unexposed healthy individuals. Until now, there is no data on T cell immunity to SARS-CoV-2 infection in CVID. This study aimed to evaluate reactive T cells to human endemic corona viruses (HCoV) and to study pre-existing SARS-CoV-2 reactive T cells in unexposed CVID patients. We evaluated SARS-CoV-2- and HCoV-229E and –OC43 reactive T cells in response to seven peptide pools, including spike and nucleocapsid (NCAP) proteins, in 11 unexposed CVID, 12 unexposed and 11 post COVID-19 healthy controls (HC). We further characterized reactive T cells by IFNγ, TNFα and IL-2 profiles. SARS-CoV-2 spike-reactive CD4+ T cells were detected in 7 of 11 unexposed CVID patients, albeit with fewer multifunctional (IFNγ/TNFα/IL-2) cells than unexposed HC. CVID patients had no SARS-CoV-2 NCAP reactive CD4+ T cells and less reactive CD8+ cells compared to unexposed HC. We observed a correlation between T cell reactivity against spike of SARS-CoV-2 and HCoVs in unexposed, but not post COVID-19 HC, suggesting cross-reactivity. T cell responses in post COVID-19 HC could be distinguished from unexposed HC by higher frequencies of triple-positive NCAP reactive CD4+ T cells. Taken together, SARS-CoV-2 reactive T cells are detectable in unexposed CVID patients albeit with lower recognition frequencies and polyfunctional potential. Frequencies of triple-functional reactive CD4+ cells might provide a marker to distinguish HCoV cross-reactive from SARS-CoV-2 specific T cell responses. Our data provides evidence, that anti-viral T cell immunity is not relevantly impaired in most CVID patients.

scholarly journals Induction of Protective Cytotoxic T Cell Responses in the Presence of High Titers of  Virus-neutralizing Antibodies: Implications for Passive and Active Immunization

1998 ◽  
Vol 187 (4) ◽  
pp. 649-654 ◽  
Author(s):  
Peter Seiler ◽  
Marie-Anne Bründler ◽  
Christine Zimmermann ◽  
Doris Weibel ◽  
Michael Bruns ◽  
...  
Keyword(s):  
T Cell ◽  
Neutralizing Antibodies ◽  
T Cell Responses ◽  
Lymphocytic Choriomeningitis ◽  
Active Immunization ◽  
Cytotoxic T Cell ◽  
Protective Antibody ◽  
Cell Responses ◽  
Cell Immunity ◽  
Cytotoxic T Cell Responses

The effect of preexistent virus-neutralizing antibodies on the active induction of antiviral T cell responses was studied in two model infections in mice. Against the noncytopathic lymphocytic choriomeningitis virus (LCMV), pretreatment with neutralizing antibodies conferred immediate protection against systemic virus spread and controlled the virus below detectable levels. However, presence of protective antibody serum titers did not impair induction of antiviral cytotoxic T lymphocyte (CTL) responses after infection with 102 PFU of LCMV. These CTLs efficiently protected mice independent of antibodies against challenge with LCMV–glycoprotein recombinant vaccinia virus; they also protected against otherwise lethal lymphocytic choriomeningitis caused by intracerebral challenge with LCMV-WE, whereas transfused antibodies alone did not protect, and in some cases even enhanced, lethal lymphocytic choriomeningitis. Against the cytopathic vesicular stomatitis virus (VSV), specific CTLs and Th cells were induced in the presence of high titers of VSV-neutralizing antibodies after infection with 106 PFU of VSV, but not at lower virus doses. Taken together, preexistent protective antibody titers controlled infection but did not impair induction of protective T cell immunity. This is particularly relevant for noncytopathic virus infections since both virus-neutralizing antibodies and CTLs are essential for continuous virus control. Therefore, to vaccinate against such viruses parallel or sequential passive and active immunization may be a suitable vaccination strategy to combine advantages of both virus-neutralizing antibodies and CTLs.

scholarly journals Long-term follow-up of SARS-CoV-2 convalescents reveals distinct magnitude of spike-specific immunity after viral re-exposure and vaccination

2021 ◽  
Author(s):  
Percy Knolle ◽  
Nina Körber ◽  
Alina Priller ◽  
Sarah Yazici ◽  
Tanja Bauer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Neutralizing Antibodies ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Cell Responses ◽  
Specific Immunity ◽  
Cell Immunity

Abstract Infection with the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is controlled by the host´s immune response1-4, but longitudinal follow-up studies of virus-specific immunity to evaluate protection from re-infection are lacking. Here, we report the results from a prospective study that started during the first wave of the COVID-19 pandemic in spring 2020, where we identified 91 convalescents from mild SARS-CoV-2 infection among 4554 health care workers. We followed the dynamics and magnitude of spike-specific immunity in convalescents during the spontaneous course over ≥ 9 months, after SARS-CoV-2 re-exposure and after BNT162b2 mRNA vaccination. Virus-neutralizing antibodies and spike-specific T cell responses with predominance of IL-2-secreting polyfunctional CD4 T cells continuously declined over 9 months, but remained detectable at low levels. After a single vaccination, convalescents simultaneously mounted strong antibody and T cell responses against the SARS-CoV-2 spike proteins. In naïve individuals, a prime vaccination induced preferentially IL-2-secreting CD4 T cells that preceded production of spike-specific virus-neutralizing antibodies after boost vaccination. Response to vaccination, however, was not homogenous. Compared to four individuals among 455 naïve vaccinees (0.9%), we identified 5/82 (6.1%) convalescents with a delayed response to vaccination. These convalescents had originally developed dysfunctional spike-specific immune responses after SARS-CoV-2 infection, and required prime and boost vaccination to develop strong spike-specific immunity. Importantly, during the second wave of the COVID-19 pandemic in fall/winter of 2021 and prior to vaccination we detected a surge of virus-neutralizing antibodies consistent with re-exposure to SARS-CoV-2 in 6 out of 82 convalescents. The selective increase in virus-neutralizing antibodies occurred without systemic re-activation of spike-specific T cell immunity, whereas a single BNT162b2 mRNA vaccination sufficed to induce strong spike-specific antibody and systemic T cell responses in the same individuals. These results support the notion that BNT162b2 mRNA vaccination synchronizes spike-specific immunity in all convalescents of mild SARS-CoV-2 infection and may provide additional protection from re-infection by inducing more rigorous stimulation of spike-specific T cell immunity than re-exposure with SARS-CoV-2.

scholarly journals Loss of Resistance to Mousepox during Chronic Lymphocytic Choriomeningitis Virus Infection Is Associated with Impaired T-Cell Responses and Can Be Rescued by Immunization

2019 ◽  
Vol 94 (5) ◽  
Author(s):  
Pedro Alves-Peixoto ◽  
Maria Férez ◽  
Cory J. Knudson ◽  
Carolina R. Melo-Silva ◽  
Colby Stotesbury ◽  
...  
Keyword(s):  
T Cell ◽  
Chronic Infection ◽  
Viral Infections ◽  
Acute Infection ◽  
T Cell Responses ◽  
Lymphocytic Choriomeningitis ◽  
Lymphocytic Choriomeningitis Virus ◽  
T Cell Response ◽  
Cell Responses ◽  
Chronic Viral Infections

ABSTRACT It is well established that chronic viral infections can cause immune suppression, resulting in increased susceptibility to other infectious diseases. However, the effects of chronic viral infection on T-cell responses and vaccination against highly pathogenic viruses are not well understood. We have recently shown that C57BL/6 (B6) mice lose their natural resistance to wild-type (WT) ectromelia virus (ECTV) when chronically infected with lymphocytic choriomeningitis virus (LCMV) clone 13 (CL13). Here we compared the T-cell response to ECTV in previously immunologically naive mice that were chronically infected with CL13 or that were convalescent from acute infection with the Armstrong (Arm) strain of LCMV. Our results show that mice that were chronically infected with CL13 but not those that had recovered from Arm infection have highly defective ECTV-specific CD8+ and CD4+ T-cell responses to WT ECTV. These defects are at least partly due to the chronic infection environment. In contrast to mice infected with WT ECTV, mice chronically infected with CL13 survived without signs of disease when infected with ECTV-Δ036, a mutant ECTV strain that is highly attenuated. Strikingly, mice chronically infected with CL13 mounted a strong CD8+ T-cell response to ECTV-Δ036 and survived without signs of disease after a subsequent challenge with WT ECTV. Our work suggests that enhanced susceptibility to acute viral infections in chronically infected individuals can be partly due to poor T-cell responses but that sufficient T-cell function can be recovered and resistance to acute infection can be restored by immunization with highly attenuated vaccines. IMPORTANCE Chronic viral infections may result in immunosuppression and enhanced susceptibility to infections with other pathogens. For example, we have recently shown that mice chronically infected with lymphocytic choriomeningitis virus (LCMV) clone 13 (CL13) are highly susceptible to mousepox, a disease that is caused by ectromelia virus and that is the mouse homolog of human smallpox. Here we show chronic CL13 infection severely disrupts the expansion, proliferation, activation, and cytotoxicity of T cells in response due at least in part to the suppressive effects of the chronic infection milieu. Notably, despite this profound immunodeficiency, mice chronically infected with CL13 could be protected by vaccination with a highly attenuated variant of ECTV. These results demonstrate that protective vaccination of immunosuppressed individuals is possible, provided that proper immunization tools are used.

HLA-Class I Alleles Impact Susceptibility To EBV+ Classical Hodgkin Lymphoma By Altering EBV Latent Antigen-Specific CD8+ T-Cell Immune Hierarchies

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 630-630
Author(s):  
Maher K Gandhi ◽  
Rebekah M Brennan ◽  
Leesa Wockner ◽  
Pratip K Chattopadhyay ◽  
Mario Roederer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Hla Class I ◽  
Cd8 T Cell ◽  
T Cell Immunity ◽  
Class I ◽  
Cell Responses ◽  
Cell Immunity

Abstract In Epstein-Barr virus (EBV) classical Hodgkin lymphoma (EBV+ cHL), Hodgkin-Reed Sternberg cell antigen presentation is intact, with viral expression restricted to sub-dominant latent-antigens including LMP1/2A. Large epidemiological studies have reported differential HLA-class I (HLA-I) susceptibility to EBV+ cHL. The functional basis for these observations is unknown. HLA-I molecules present viral peptides for recognition by CD8+ T-cells, and it may be that the relative risk of developing EBV+ cHL is due to HLA-I alleles influencing the magnitude of CD8+ T-cell immunity against relevant EBV-specific antigens. However this remains speculative, with immunological evidence lacking. Several non-HLA-I linked genetic susceptibility loci have been identified, and HLA-I associations may simply represent markers for genes of diverse functions that are in linkage disequilibrium to the HLA-I region. We undertook an Australasian Leukaemia and Lymphoma Group study to address this fundamental question, utilizing 4 distinct but complimentary experimental approaches. 1. 9 EBV+ cHL and 11 EBV-ve cHL pre-therapy PBMC samples were tested for ex-vivo IFNγ, TNFα and CD107a CD8+ T-cell immunity, using overlapping LMP1 and LMP2A peptide pools. The non-HRS expressed EBV-lytic protein BZLF1 was a control. Highly stringent FACS gating was used to maximize specificity. Results were interrogated using Profile and SPICE analysis. Interestingly IFNγ, TNFα and CD107 CD8+ T-cell responses in HLA-A*02 EBV+ cHL (but not EBV-ve cHL) patients were greater than non-HLA-A*02 (LMP1 p=0.002; LMP2A p=0.03; combined LMP1/LMP2A p=0.005), whereas BZLF1 was equivalent, indicating that HLA-I provides differential CD8+ T-cell immunity against relevant EBV-latent antigens in EBV+ cHL but not EBV-ve cHL. 2. However, up to 4 different HLA-A/B molecules can potentially present relevant EBV-derived epitopes in each individual, adding a confounding layer of complexity to single allele-based effects. To overcome this and enhance sensitivity, we used the mutant HLA-I 721.221 cell-line (pulsed with LMP2A), transfected with either HLA-A*01, HLA-A*02, HLA-A*03 or HLA-B*08 alleles, as antigen presenting cells to in-vitro expand LMP2A-specific CD8+ T-cells from HLA-A*02 heterozygotes. This found ∼90% of the HLA-I LMP2A response was restricted through HLA-A*02. 3. In contrast to EBV+ cHL, in EBV-post-transplant lymphoproliferative disorders (EBV+ PTLD) the immunogenic EBNA3A/3B/3C latent-antigens are expressed. We compared HLA-I associations in 110 cHL (35% EBV+ cHL) to 153 PTLD (63% EBV+ PTLD) patients. Using Bonferoni corrected statistics, we confirmed that HLA-A*02 and HLA-A*01 homozygotes had lower and higher susceptibility to EBV+ cHL respectively, and that HLA-B*37 was positively associated. Notably, no HLA-I associations with EBV+ PTLD were found. 4. To investigate the impact of HLA-I on the hierarchy of CD8+ T-cell immunity to sub-dominant (LMP1/2A) and immune-dominant (EBNA3A/3B/3C) EBV-latent proteins, we analysed the diversity of HLA-class I restricted T-cells in 30 healthy EBV+ participants. To supplement 30 ‘defined' (i.e. validated) HLA-I EBV-latent antigen epitopes and expand HLA-I coverage, we identified 31 ‘SYFPEITHI' bioinformatically ‘predicted' peptide epitopes for HLA-A*01, HLA-A*03 or HLA-B*37 restricted EBV-latent antigens. All SYFPEITHI scores were ≥21, and thermal stability circular dichroism analysis (HLA-A*01) or MHC stabilization assays on T2 cells (HLA-A*03) confirmed peptide binding to HLA-I. Ex-vivo CD107 CD8+ T-cell assays for the 61 peptides, found that sub-dominant LMP1/2A-specific peptide responses were largely confined to HLA-A*02 (Fig 1A), whilst immuno-dominant CD8+ T-cell responses were stimulated by peptides presented by numerous HLA-I alleles (Fig 1B). These data combined illustrate that differential HLA-I-associated susceptibility to EBV+ cHL reflects altered EBV latent antigen-specific CD8+ T-cell immune hierarchies. For lymphomas expressing a restricted set of poorly immunogenic proteins, even modest CD8+ T-cell responses against relevant tumor-associated proteins confer protection, with broad implications for EBV-vaccine design. Studies are required to determine if similar mechanisms are applicable to non-lymphoid EBV+ malignancies with restricted latency such as undifferentiated nasopharngeal carcinoma. Disclosures: No relevant conflicts of interest to declare.

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