Orf Virus-Based Vaccine Vector D1701-V Induces Strong CD8+ T Cell Response against the Transgene but Not against ORFV-Derived Epitopes

The potency of viral vector-based vaccines depends on their ability to induce strong transgene-specific immune response without triggering anti-vector immunity. Previously, Orf virus (ORFV, Parapoxvirus) strain D1701-V was reported as a novel vector mediating protection against viral infections. The short-lived ORFV-specific immune response and the absence of virus neutralizing antibodies enables repeated immunizations and enhancement of humoral immune responses against the inserted antigens. However, only limited information exists about the D1701-V induced cellular immunity. In this study we employed major histocompatibility complex (MHC) ligandomics and immunogenicity analysis to identify ORFV-specific epitopes. Using liquid chromatography-tandem mass spectrometry we detected 36 ORFV-derived MHC I peptides, originating from various proteins. Stimulated splenocytes from ORFV-immunized mice did not exhibit specific CD8+ T cell responses against the tested peptides. In contrast, immunization with ovalbumin-expressing ORFV recombinant elicited strong SIINFEKL-specific CD8+ T lymphocyte response. In conclusion, our data indicate that cellular immunity to the ORFV vector is negligible, while strong CD8+ T cell response is induced against the inserted transgene. These results further emphasize the ORFV strain D1701-V as an attractive vector for vaccine development. Moreover, the presented experiments describe prerequisites for the selection of T cell epitopes exploitable for generation of ORFV-based vaccines by reverse genetics.

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Magnitude and Dynamics of the T-Cell Response to SARS-CoV-2 Infection at Both Individual and Population Levels

10.1101/2020.07.31.20165647 ◽

2020 ◽

Cited By ~ 14

Author(s):

Thomas M Snyder ◽

Rachel M Gittelman ◽

Mark Klinger ◽

Damon H May ◽

Edward J Osborne ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

Cell Response ◽

Vaccine Development ◽

Human Leukocyte ◽

Cd8 T Cell ◽

T Cell Response ◽

Clinical Diagnostics ◽

Cell Repertoire

T cells are involved in the early identification and clearance of viral infections and also support the development of antibodies by B cells. This central role for T cells makes them a desirable target for assessing the immune response to SARS-CoV-2 infection. Here, we combined two high-throughput immune profiling methods to create a quantitative picture of the T-cell response to SARS-CoV-2. First, at the individual level, we deeply characterized 3 acutely infected and 58 recovered COVID-19 subjects by experimentally mapping their CD8 T-cell response through antigen stimulation to 545 Human Leukocyte Antigen (HLA) class I presented viral peptides (class II data in a forthcoming study). Then, at the population level, we performed T-cell repertoire sequencing on 1,815 samples (from 1,521 COVID-19 subjects) as well as 3,500 controls to identify shared "public" T-cell receptors (TCRs) associated with SARS-CoV-2 infection from both CD8 and CD4 T cells. Collectively, our data reveal that CD8 T-cell responses are often driven by a few immunodominant, HLA-restricted epitopes. As expected, the T-cell response to SARS-CoV-2 peaks about one to two weeks after infection and is detectable for at least several months after recovery. As an application of these data, we trained a classifier to diagnose SARS-CoV-2 infection based solely on TCR sequencing from blood samples, and observed, at 99.8% specificity, high early sensitivity soon after diagnosis (Day 3-7 = 85.1% [95% CI = 79.9-89.7]; Day 8-14 = 94.8% [90.7-98.4]) as well as lasting sensitivity after recovery (Day 29+/convalescent = 95.4% [92.1-98.3]). These results demonstrate an approach to reliably assess the adaptive immune response both soon after viral antigenic exposure (before antibodies are typically detectable) as well as at later time points. This blood-based molecular approach to characterizing the cellular immune response has applications in clinical diagnostics as well as in vaccine development and monitoring.

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Nano-Microparticle Platforms in Developing Next-Generation Vaccines

Vaccines ◽

10.3390/vaccines9060606 ◽

2021 ◽

Vol 9 (6) ◽

pp. 606

Author(s):

Giuseppe Cappellano ◽

Hugo Abreu ◽

Chiara Casale ◽

Umberto Dianzani ◽

Annalisa Chiocchetti

Keyword(s):

Immune Response ◽

T Cell ◽

Cell Response ◽

Humoral Response ◽

Cd8 T Cell ◽

T Cell Response ◽

Next Generation ◽

Emerging Viruses ◽

Whole Cells ◽

Effector Functions

The first vaccines ever made were based on live-attenuated or inactivated pathogens, either whole cells or fragments. Although these vaccines required the co-administration of antigens with adjuvants to induce a strong humoral response, they could only elicit a poor CD8+ T-cell response. In contrast, next-generation nano/microparticle-based vaccines offer several advantages over traditional ones because they can induce a more potent CD8+ T-cell response and, at the same time, are ideal carriers for proteins, adjuvants, and nucleic acids. The fact that these nanocarriers can be loaded with molecules able to modulate the immune response by inducing different effector functions and regulatory activities makes them ideal tools for inverse vaccination, whose goal is to shut down the immune response in autoimmune diseases. Poly (lactic-co-glycolic acid) (PLGA) and liposomes are biocompatible materials approved by the Food and Drug Administration (FDA) for clinical use and are, therefore, suitable for nanoparticle-based vaccines. Recently, another candidate platform for innovative vaccines based on extracellular vesicles (EVs) has been shown to efficiently co-deliver antigens and adjuvants. This review will discuss the potential use of PLGA-NPs, liposomes, and EVs as carriers of peptides, adjuvants, mRNA, and DNA for the development of next-generation vaccines against endemic and emerging viruses in light of the recent COVID-19 pandemic.

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CT Antigen-Specific Immune Response From DAC/DC Vaccine Correlates With Clinical Outcome In Patients With Relapsed Neuroblastoma

Blood ◽

10.1182/blood.v122.21.2023.2023 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2023-2023

Author(s):

Deepa Kolaseri Krishnadas ◽

Fanqi Bai ◽

Kenneth Lucas

Keyword(s):

Immune Response ◽

T Cell ◽

Immune Responses ◽

Cell Response ◽

T Cell Response ◽

Specific Immune Response ◽

Cd4 T Cell ◽

Dc Vaccine ◽

Ct Antigen ◽

Ct Antigens

Abstract Neuroblastoma is the most common solid tumor in children in the first year of life. Despite high-dose chemotherapy, irradiation and autologous stem cell transplantation, nearly half of these patients relapse, a group for whom there are limited treatment options. The cancer-testis (CT) antigens MAGE-A1, MAGE-A3 and NY-ESO-1 are expressed on neuroblastoma cells in low levels and we have previously shown that the demethylating chemotherapy drug decitabine (DAC) can upregulate the expression of CT antigens in neuroblastoma. We developed a clinical study combining DAC to upregulate CT antigens followed by a dendritic cell (DC) vaccine targeting CT antigens MAGE-A1, MAGE-A3 and NY-ESO-1. Here we report the effects of DAC/DC vaccine in generating antigen-specific immune response and evaluate if there exists a correlation between development of antigen-specific immune responses and clinical responses. The treatment regimen includes 4 cycles of therapy, each consisting of DAC 10mg/m2/day for 5 days, followed by 2 weekly vaccinations consisting of autologous DC pulsed with overlapping peptide mixes derived from full length MAGE-A1, MAGE-A3 and NY-ESO-1. The number of DC administered in the vaccine was based on patient weight, and ranged from 3 to 10 x106 cells. The topical TLR agonist imiquimod was used at the site of vaccination to facilitate immune responses to the vaccine. Peripheral blood was collected weekly to assess antigen-specific immune response. Peripheral blood mononuclear cells were archived at various time points, stimulated for 24 h with MAGE-A1, MAGE-A3 and NY-ESO-1 peptide mixes and studied for the presence of CD137+ antigen-specific cells by flow cytometry. The regimen was well tolerated and highly feasible. We were able to culture DC for 10/10 neuroblastoma patients enrolled on the study. Development of an antibody or a T cell response to the vaccine was defined as either new onset or a two fold increase in the level of antibodies or number of MAGE-A1, MAGE-A3 and NY-ESO-1 specific, CD137+ T cells over baseline levels. The clinical and immunological outcomes of seven neuroblastoma patients treated so far with the DAC/CT antigen vaccine is summarized in table 1. Two patients are in complete remission, one of whom is two years from completing therapy, and another patient is 9 months from therapy. Both these patients demonstrated an increase in the number of circulating CD3+CD8+CD137+ and CD3+CD4+CD137+ T cells against one of the CT antigens in the vaccine. Of the five patients who had disease progression, one had a partial response to his chemotherapy and radiation resistant tumor 2 months post-vaccine. This patient had an antibody response to these antigens post-vaccination but no CD8+ or CD4+ T cell response. Another patient who had no evidence of disease for 8 months following the last vaccine prior to disease recurrence had an antigen-specific CD8+ T cell response against MAGE-A1, MAGE-A3 and NY-ESO-1 antigens but no CD4+ T cell response. These data indicate that DAC/DC vaccine targeting MAGE-A1, MAGE-A3 and NY-ESO-1 are efficient in generating an antigen-specific immune response in four of seven patients studied and there exist a correlation between the presence of immune response and positive clinical outcome. Disclosures: No relevant conflicts of interest to declare.

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EBV-positive lymphoma patients have a selective deficiency in EBV immunity

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.21032 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 21032-21032

Author(s):

K. N. Heller ◽

P. G. Steinherz ◽

C. S. Portlock ◽

C. Münz

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

Immune Responses ◽

Healthy Volunteers ◽

Cell Response ◽

T Cell Responses ◽

T Cell Response ◽

Specific Immune Response ◽

Cell Responses

21032 Background: Epstein-Barr virus (EBV) asymptomatically establishes persistent infections in more than 90% of the adult population. However, due to effective immune control, only a minority of infected carriers develops spontaneous EBV-associated lymphomas. Since EBV nuclear antigen-1 (EBNA1) is the only protein expressed in all proliferating EBV infected cells we hypothesize that EBNA1 specific immune response is critical in preventing EBV-positive lymphomas. Methods: After informed consent, peripheral blood from healthy volunteers and lymphoma patients (prior to therapy- no evidence of cytopenia) were stimulated (ex vivo) with overlapping peptides covering the immunogenic EBNA1 (aa400–641) sequence. Frequency of EBNA1-specific T-cells were assessed by intracellular cytokine staining and flow cytometric proliferation assays. Cytokine pattern, surface marker phenotype and functional reactivity against EBV specific and control antigens were analyzed. Results: Patient and volunteer immune responses to control antigens and other viruses were assessed and statistically indistinguishable. EBNA1 specific CD4+ T cell responses were detected among 18 of 20 healthy carriers, and among 10 of 16 patients with EBV-negative lymphoma (relative to healthy volunteers p=0.145 via paired student T test). None of the patients with EBV-positive lymphomas (n=8) had a detectable EBNA1-specific CD4+ T-cell response (p<0.003 relative to healthy volunteers and patients with EBV-negative lymphomas). Conclusions: Healthy volunteers and patients with EBV-negative lymphoma have statistically similar EBNA1-specific CD4+ T cell responses. Although patients with EBV-positive lymphoma have intact immune responses to common viruses and antigens, they selectively lack an EBNA1-specific CD4+ T cell response. An intact EBNA1 specific immune response among patients with EBV-negaitve lymphoma implies that lymphoma is not a cause of a selective immune deficiency. On the contrary, these findings suggest that EBNA1-specific CD4+ T cells are critical in the prevention of EBV mediated lymphomas, and a defect in EBNA1 specific immunity may leave EBV carriers suseptible to EBV-positive lymphomas. EBNA1- specific CD4+ T cell function may be a new target for therapies of EBV-associated malignancies. No significant financial relationships to disclose.

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A gammaherpesvirus-secreted activator of Vβ4+ CD8+ T cells regulates chronic infection and immunopathology

Journal of Experimental Medicine ◽

10.1084/jem.20071135 ◽

2008 ◽

Vol 205 (3) ◽

pp. 669-684 ◽

Cited By ~ 46

Author(s):

Andrew G. Evans ◽

Janice M. Moser ◽

Laurie T. Krug ◽

Veranika Pozharskaya ◽

Ana L. Mora ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cd8 T Cells ◽

Cell Response ◽

Cell Activation ◽

Cd8 T Cell ◽

T Cell Response ◽

Murine Gammaherpesvirus

Little is known about herpesvirus modulation of T cell activation in latently infected individuals or the implications of such for chronic immune disorders. Murine gammaherpesvirus 68 (MHV68) elicits persistent activation of CD8+ T cells bearing a Vβ4+ T cell receptor (TCR) by a completely unknown mechanism. We show that a novel MHV68 protein encoded by the M1 gene is responsible for Vβ4+ CD8+ T cell stimulation in a manner reminiscent of a viral superantigen. During infection, M1 expression induces a Vβ4+ effector T cell response that resists functional exhaustion and appears to suppress virus reactivation from peritoneal cells by means of long-term interferon-γ (IFNγ) production. Mice lacking an IFNγ receptor (IFNγR−/−) fail to control MHV68 replication, and Vβ4+ and CD8+ T cell activation by M1 instead contributes to severe inflammation and multiorgan fibrotic disease. Thus, M1 manipulates the host CD8+ T cell response in a manner that facilitates latent infection in an immunocompetent setting, but promotes disease during a dysregulated immune response. Identification of a viral pathogenecity determinant with superantigen-like activity for CD8+ T cells broadens the known repertoire of viral immunomodulatory molecules, and its function illustrates the delicate balance achieved between persistent viruses and the host immune response.

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Initial viral load determines the magnitude of the human CD8 T cell response to yellow fever vaccination

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1500475112 ◽

2015 ◽

Vol 112 (10) ◽

pp. 3050-3055 ◽

Cited By ~ 70

Author(s):

Rama S. Akondy ◽

Philip L. F. Johnson ◽

Helder I. Nakaya ◽

Srilatha Edupuganti ◽

Mark J. Mulligan ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Viral Load ◽

T Cell ◽

Yellow Fever ◽

Cd8 T Cells ◽

Cell Response ◽

Cd8 T Cell ◽

T Cell Response ◽

Virus Load

CD8 T cells are a potent tool for eliminating intracellular pathogens and tumor cells. Thus, eliciting robust CD8 T-cell immunity is the basis for many vaccines under development. However, the relationship between antigen load and the magnitude of the CD8 T-cell response is not well-described in a human immune response. Here we address this issue by quantifying viral load and the CD8 T-cell response in a cohort of 80 individuals immunized with the live attenuated yellow fever vaccine (YFV-17D) by sampling peripheral blood at days 0, 1, 2, 3, 5, 7, 9, 11, 14, 30, and 90. When the virus load was below a threshold (peak virus load < 225 genomes per mL, or integrated virus load < 400 genome days per mL), the magnitude of the CD8 T-cell response correlated strongly with the virus load (R2∼ 0.63). As the virus load increased above this threshold, the magnitude of the CD8 T-cell responses saturated. Recent advances in CD8 T-cell–based vaccines have focused on replication-incompetent or single-cycle vectors. However, these approaches deliver relatively limited amounts of antigen after immunization. Our results highlight the requirement that T-cell–based vaccines should deliver sufficient antigen during the initial period of the immune response to elicit a large number of CD8 T cells that may be needed for protection.

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Immunization with a Mixture of HIV Env DNA and VLP Vaccines Augments Induction of CD8 T Cell Responses

Journal of Biomedicine and Biotechnology ◽

10.1155/2010/497219 ◽

2010 ◽

Vol 2010 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

Ling Ye ◽

Zhiyuan Wen ◽

Ke Dong ◽

Lei Pan ◽

Zhigao Bu ◽

...

Keyword(s):

Immune Response ◽

T Cell ◽

Dna Vaccine ◽

Cell Response ◽

T Cell Responses ◽

Cd8 T Cell ◽

T Cell Response ◽

Antibody Responses ◽

Cell Responses ◽

Virus Like Particle

The immune response induced by immunization with HIV Env DNA and virus-like particle (VLP) vaccines was investigated. Immunization with the HIV Env DNA vaccine induced a strong CD8 T cell response but relatively weak antibody response against the HIV Env whereas immunization with VLPs induced higher levels of antibody responses but little CD8 T cell response. Interestingly, immunization with a mixture the HIV Env DNA and VLP vaccines induced enhanced CD8 T cell and antibody responses. Further, it was observed that the mixing of DNA and VLP vaccines during immunization is necessary for augmenting induction of CD8 T cell responses and such augmentation of CD8 T cell responses was also observed by mixing the HIV Env DNA vaccine with control VLPs. These results show that immunization with a mixture of DNA and VLP vaccines combines advantages of both vaccine platforms for eliciting high levels of both antibody and CD8 T cell responses.

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