Mycobacterium bovis BCG Vaccination Induces Divergent Proinflammatory or Regulatory T Cell Responses in Adults

ABSTRACTMycobacterium bovisbacillus Calmette-Guérin (BCG), the only currently available vaccine against tuberculosis, induces variable protection in adults. Immune correlates of protection are lacking, and analyses on cytokine-producing T cell subsets in protected versus unprotected cohorts have yielded inconsistent results. We studied the primary T cell response, both proinflammatory and regulatory T cell responses, induced by BCG vaccination in adults. Twelve healthy adult volunteers who were tuberculin skin test (TST) negative, QuantiFERON test (QFT) negative, and BCG naive were vaccinated with BCG and followed up prospectively. BCG vaccination induced an unexpectedly dichotomous immune response in this small, BCG-naive, young-adult cohort: BCG vaccination induced either gamma interferon-positive (IFN-γ+) interleukin 2-positive (IL-2+) tumor necrosis factor α-positive (TNF-α+) polyfunctional CD4+T cells concurrent with CD4+IL-17A+and CD8+IFN-γ+T cells or, in contrast, virtually absent cytokine responses with induction of CD8+regulatory T cells. Significant induction of polyfunctional CD4+IFN-γ+IL-2+TNF-α+T cells and IFN-γ production by peripheral blood mononuclear cells (PBMCs) was confined to individuals with strong immunization-induced local skin inflammation and increased serum C-reactive protein (CRP). Conversely, in individuals with mild inflammation, regulatory-like CD8+T cells were uniquely induced. Thus, BCG vaccination either induced a broad proinflammatory T cell response with local inflammatory reactogenicity or, in contrast, a predominant CD8+regulatory T cell response with mild local inflammation, poor cytokine induction, and absent polyfunctional CD4+T cells. Further detailed fine mapping of the heterogeneous host response to BCG vaccination using classical and nonclassical immune markers will enhance our understanding of the mechanisms and determinants that underlie the induction of apparently opposite immune responses and how these impact the ability of BCG to induce protective immunity to TB.

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The Response to Repeated Vaccination with PR1 and WT1 Peptides Admixed in Montanide Adjuvant Is Transient and Fails to Induce Sustained Anti-Leukemia Responses in Patients with Myeloid Malignancies.

Blood ◽

10.1182/blood.v114.22.4096.4096 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4096-4096

Author(s):

Katayoun Rezvani ◽

Agnes S. M. Yong ◽

Stephan Mielke ◽

Behnam Jafarpour ◽

Bipin N. Savani ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cell Response ◽

T Cell Responses ◽

Cd8 T Cell ◽

T Cell Response ◽

Gm Csf ◽

Cell Responses ◽

Ifn Γ

Abstract Abstract 4096 Poster Board III-1031 We previously demonstrated the immunogenicity of a combined vaccine approach employing two leukemia-associated antigenic peptides, PR1 and WT1 (Rezvani Blood 2008). Eight patients with myeloid malignancies received one subcutaneous 0.3 mg and 0.5 mg dose each of PR1 and WT1 vaccines in Montanide adjuvant, with 100 μg of granulocyte-macrophage colony-stimulating factor (GM-CSF). CD8+ T-cell responses against PR1 or WT1 were detected in all patients as early as 1 week post-vaccination. However, responses were only sustained for 3-4 weeks. The emergence of PR1 or WT1-specific CD8+ T-cells was associated with a significant but transient reduction in minimal residual disease (MRD) as assessed by WT1 expression, suggesting a vaccine-induced anti-leukemia response. Conversely, loss of response was associated with reappearance of WT1 transcripts. We hypothesized that maintenance of sustained or at least repetitive responses may require frequent boost injections. We therefore initiated a phase 2 study of repeated vaccination with PR1 and WT1 peptides in patients with myeloid malignancies. Five patients with acute myeloid leukemia (AML) and 2 patients with myelodysplastic syndrome (MDS) were recruited to receive 6 injections at 2 week intervals of PR1 and WT1 in Montanide adjuvant, with GM-CSF as previously described. Six of 7 patients completed 6 courses of vaccination and follow-up as per protocol, to monitor toxicity and immunological responses. Responses to PR1 or WT1 vaccine were detected in all patients after only 1 dose of vaccine. However, additional boosting did not further increase the frequency of PR1 or WT1-specific CD8+ T-cell response. In 4/6 patients the vaccine-induced T-cell response was lost after the fourth dose and in all patients after the sixth dose of vaccine. To determine the functional avidity of the vaccine-induced CD8+ T-cell response, the response of CD8+ T-cells to stimulation with 2 concentrations of PR1 and WT1 peptides (0.1 and 10 μM) was measured by IC-IFN-γ staining. Vaccination led to preferential expansion of low avidity PR1 and WT1 specific CD8+ T-cell responses. Three patients (patients 4, 6 and 7) returned 3 months following the 6th dose of PR1 and WT1 peptide injections to receive a booster vaccine. Prior to vaccination we could not detect the presence of PR1 and WT1 specific CD8+ T-cells by direct ex-vivo tetramer and IC-IFN-γ assay or with 1-week cultured IFN-γ ELISPOT assay, suggesting that vaccination with PR1 and WT1 peptides in Montanide adjuvant does not induce memory CD8+ T-cell responses. This observation is in keeping with recent work in a murine model where the injection of minimal MHC class I binding peptides derived from self-antigens mixed with IFA adjuvant resulted in a transient effector CD8+ T cell response with subsequent deletion of these T cells and failure to induce CD8+ T cell memory (Bijker J Immunol 2007). This observation can be partly explained by the slow release of vaccine peptides from the IFA depot without systemic danger signals, leading to presentation of antigen in non-inflammatory lymph nodes by non-professional antigen presenting cells (APCs). An alternative explanation for the transient vaccine-induced immune response may be the lack of CD4+ T cell help. In summary these data support the immunogenicity of PR1 and WT1 peptide vaccines. However new approaches will be needed to induce long-term memory responses against leukemia antigens. To avoid tolerance induction we plan to eliminate Montanide adjuvant and use GM-CSF alone. Supported by observations that the in vivo survival of CD8+ T-effector cells against viral antigens are improved by CD4+ helper cells, we are currently attempting to induce long-lasting CD8+ T-cell responses to antigen by inducing CD8+ and CD4+ T-cell responses against class I and II epitopes of WT1 and PR1. Disclosures: No relevant conflicts of interest to declare.

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Hepatitis C Virus Induces Regulatory T Cells by Naturally Occurring Viral Variants to Suppress T Cell Responses

Clinical and Developmental Immunology ◽

10.1155/2011/806061 ◽

2011 ◽

Vol 2011 ◽

pp. 1-15 ◽

Cited By ~ 17

Author(s):

Matthew F. Cusick ◽

Jennifer J. Schiller ◽

Joan C. Gill ◽

David D. Eckels

Keyword(s):

T Cells ◽

Hepatitis C Virus ◽

Hepatitis C ◽

T Cell ◽

Regulatory T Cell ◽

Cell Response ◽

T Cell Response ◽

Cell Responses ◽

Naturally Occurring ◽

Specific Manner

Regulatory T cell markers are increased in chronically infected individuals with the hepatitis C virus (HCV), but to date, the induction and maintenance of Tregs in HCV infection has not been clearly defined. In this paper, we demonstrate that naturally occurring viral variants suppress T cell responses to cognate NS3358-375in an antigen-specific manner. Of four archetypal variants, S370P induced regulatory T cell markers in comparison to NS3358-375-stimulated CD4 T cells. Further, the addition of variant-specific CD4 T cells back into a polyclonal culture in a dose-dependent manner inhibited the T cell response. These results suggest that HCV is able to induce antigen-specific regulatory T cells to suppress the antiviral T cell response in an antigen-specific manner, thus contributing to a niche within the host that could be conducive to HCV persistence.

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T-Cell and B-Cell Responses After Vaccination against Influenza Virus and Pneumococcus in Chronic Phase CML Patients Treated with Tyrosine Kinase Inhibitors.

Blood ◽

10.1182/blood.v114.22.2214.2214 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2214-2214

Author(s):

Hugues de Lavallade ◽

Melanie Hart ◽

Ian H Gabriel ◽

Peter Kelleher ◽

Abdullah Alsuliman ◽

...

Keyword(s):

T Cells ◽

Influenza Virus ◽

T Cell ◽

B Cell ◽

Cell Response ◽

T Cell Responses ◽

T Cell Response ◽

Healthy Controls ◽

Cell Responses ◽

Tnf Α

Abstract Abstract 2214 Poster Board II-191 Imatinib (IM), nilotinib and dasatinib are remarkably effective as single-agent treatments for chronic myeloid leukemia (CML) in chronic phase (CP). However little is known on their potential impact on the immune system and to date no human in vivo data are available. Data from in vitro and animal studies on the effects of IM on the immune response have been contradictory ranging from impaired antigen-specific T-cell response to enhanced stimulation of tolerant T cells. In addition few data are available to assess potential immunomodulatory effects of the second-generation tyrosine kinase inhibitors (TKIs) nilotinib and dasatinib. Dasatinib has inhibitory activity against a broader range of protein kinases than imatinib including the Src family kinases Lck and Fyn, both of which are associated with T-cell receptor primary signal transduction pathways. Dasatinib may also inhibit B cell signaling through the Lyn pathway which may have potential implications for immunotherapeutic strategies. An understanding of the effects of different TKIs on the immune response will have implications for the development of immunotherapeutic strategies. The aim of this study was to prospectively analyze humoral and cellular immune responses to vaccination against influenza virus (Flu) and Pneumococcus in CP-CML patients treated with IM, dasatinib or nilotinib compared to healthy controls. Fifty CP-CML patients on standard dose TKIs (IM, n=22; dasatinib, n=15; nilotinib, n=13) and 15 healthy controls were vaccinated against Flu (Inflenza vaccine Ph. Eur. 2008/2009, CSL biotherapies) and pneumococcus (Pneumovax II, Sanofi Pasteur MSD). Samples were taken pre and at 1 and 3 months post-vaccination. Titers of IgM and IgG anti-pneumococcal were determined using ELISA technology. A positive response was defined as an IgM serum titer >100 U/ml at 1 month; IgG response was considered positive for IgG >200 U/ml at 1 or 3 months. To investigate possible correlation between B cell subsets and the pneumococcal humoral response we evaluated IgM memory B cells (CD19+ CD27+ IgMhigh IgDlow) and switched memory B cell (CD19+ CD27+ IgM- IgD-) subsets using flow cytometry. We analyzed the immunological T-cell response to influenza virus both quantitatively and qualitatively using flow cytometry for intracellular TNF-α, IFN-gamma and IL2 and the cytotoxicity marker CD107a. A response was considered positive if there was a minimum of 0.10% Flu-specific TNF-α producing T-cells and the percentage of antigen-specific TNF-α producing T-cells was 2-fold or higher compared to pre-vaccination level. Preliminary results on 28 patients and 11 healthy controls have been analyzed thus far. Significantly fewer patients on TKIs mounted an anti-pneumococcal IgM response (IgM serum titer > 100 U/ml) compared to healthy controls (9/28 versus 8/11, p=0.033). An anti-pneumococcal IgM response was detected in 20%, 37.5% and 40% of CML patients on dasatinib, nilotinib and IM respectively, and in 73% of the healthy controls. Moreover, patients on TKI had significantly lower levels of anti-pneumococcal IgM at 1 month compared to healthy controls (median, 84.5 U/ml, range 5 to 200 vs 200 U/ml, range 15 to 200, p=0.006). At 1 month the median levels of IgM in patients on dasatinib, nilotinib and IM were 55 U/ml (range, 12 to 172), 87 U/ml (range, 8-138) and 90 U/ml (range, 5 to 200) respectively. We have so far analyzed CD8 and CD4 T cell responses to Flu vaccination in 15 patients on TKI and 5 healthy controls. Prior to vaccination, T cell responses against Flu were detected in 4/15 patients on TKI and 1/5 healthy controls, indicating pre-existing memory T cell responses to Flu. In these subjects the T-cell response to Flu did not increase significantly after vaccination and as such the response was defined as negative. A significant T-cell response to Flu was seen in 7/15 patients on TKI (median 0.28% TNF-α+CD4+ T cells, range 0.10–2.25%) and in 3/5 healthy control (median 0.79% TNF-α+CD4+T cells, range 0.12–1.34%). These preliminary results suggest that in patients with CML on TKIs the IgM B cell response to vaccination with Pneumovax is significantly impaired compared to healthy controls. We have as yet not detected a significant difference in T-cell response following vaccination with Flu in CML patients on TKIs compared to healthy controls. We are in the process of analyzing the remaining samples. Disclosures: Marin: Novartis: Consultancy, Research Funding.

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Cytomegalovirus-Specific T Cells Are Elicited Early After Umbilical Cord Blood Transplant but Fail to Expand In Vivo and Control Virus Replication

Blood ◽

10.1182/blood.v118.21.1974.1974 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1974-1974

Author(s):

Suzanne M. McGoldrick ◽

Abraham Guerrero ◽

Tori N. Yamamoto ◽

Colleen Delaney ◽

Stanley R. Riddell

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cell Response ◽

Cd8 T Cell ◽

T Cell Response ◽

Cd4 T Cell ◽

Time Points ◽

Cell Responses ◽

Ifn Γ

Abstract Abstract 1974 Cytomegalovirus (CMV) is a major infectious complication in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) and has been linked to deficiencies of virus-specific T cell immunity. Compared to bone marrow or peripheral blood stem cell transplants, recipients of single or double umbilical cord blood transplants (UCBT) receive lower numbers of donor T cells that have not previously been primed to CMV and are at increased risk for early and recurrent CMV infections. At our institution, the rate of CMV reactivation in CMV seropositive patients undergoing CBT is close to 100% with standard dose Acyclovir as prophylaxis [Delaney unpublished data]. Here, we systematically analyzed the kinetics of recovery, durability, and specificity of CMV-specific CD8+ and CD4+ T cell responses in UCBT recipients. CD8 T cell responses to CMV were analyzed by interferon γ (IFN-γ) intracellular cytokine staining after stimulating recipient peripheral blood mononuclear cells (PBMC) obtained at various time points after CBT with autologous patient fibroblasts infected with the RV798 virus, which is a mutant CMV strain that lacks the viral US genes that downregulate class I MHC and can present all potentially immunogenic epitopes of the virus. The mean absolute CD8 T cell counts were 59, 93 and 213 cells/μl and the mean CD4 T cell counts were 154, 223 and 397 cells/μl in PBMC at day 56, 180 and 365 respectively. Direct assays of PBMC after a 4–6 hour stimulation with RV798-infected fibroblasts did not detect a significant frequency of IFN-γ+ CD8+ T cells in CBT recipients, in contrast to normal CMV+ donors that exhibited frequencies of CD8+ T cells of 2–10%. However, IFN-γ+ CMV specific CD8 T cells were readily detectable in PBMC obtained as early as day 42 after UCBT from 8 out of 8 CMV positive CBT recipients after a 10 day stimulation with RV798 infected fibroblasts. These responses were sustained at multiple time points through day 365 post transplant. This result was not a consequence of in vitro priming of CD8 T cells by prolonged stimulation with RV798 since we did not detect a CMV-specific T cell response in 3 out of 3 CMV seronegative recipients at any time through day 365 with the same assay. To assess CD4+ T cell responses, we performed lymphoproliferative assays (LPA) by stimulating patient PBMC obtained at the same time points with whole CMV antigen. The proportion of patients with a positive response at day 56, 80, 180 and 365 was 0.38, 0.50, 0.88, and 1.0 respectively. All of the CMV positive CBT recipients in our study had multiple occurrences of CMV reactivation throughout the first year post CBT requiring antiviral drug therapy. The CMV-specific CD8 T cell response in normal CMV+ individuals recognizes a large number of distinct dominant and subdominant antigens and a potential explanation for the failure to control CMV after CBT is that the T cell response may not be sufficiently diverse. We analyzed the specificity of CMV specific CD8+ T cells that developed after CBT in 4 recipients by assessing recognition of COS cells transfected with the class I HLA restricting alleles and with a CMV plasmid library consisting of 142 ORFs, subdivided into pools. A response was seen in 3 out of 4 patients to at least 3 different CMV antigens by day 80 post CBT, including previously defined dominant epitopes in pp65 and this diversity was maintained through 6–12 months post transplant. One patient had a less diverse response early post CBT and the response changed over time to include recognition of new epitopes. Collectively, our results demonstrate that CD8+ and CD4+ T cells are primed to CMV antigens very early after CBT despite the infusion of limited numbers of naïve T cells and the administration of post transplant immunosuppression. The inability to control CMV infection may be due to a quantitative deficiency of CMV-specific T cells resulting from the inability of CMV-specific T cells to expand in vivo to numbers sufficient to eliminate virus replication. Disclosures: No relevant conflicts of interest to declare.

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γδ T Cells in Immunity Induced by Mycobacterium bovis Bacillus Calmette-Guérin Vaccination

Infection and Immunity ◽

10.1128/iai.72.3.1504-1511.2004 ◽

2004 ◽

Vol 72 (3) ◽

pp. 1504-1511 ◽

Cited By ~ 43

Author(s):

Jinhee Lee ◽

Keumhwa Choi ◽

Michael R. Olin ◽

Sang-Nae Cho ◽

Thomas W. Molitor

Keyword(s):

T Cells ◽

T Cell ◽

Mycobacterium Bovis ◽

Γδ T Cells ◽

T Cell Responses ◽

Γδ T Cell ◽

Bcg Vaccination ◽

Cell Responses ◽

Ifn Γ ◽

Time Point

ABSTRACT Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccination is efficacious for newborns or adults with no previous exposure to environmental mycobacteria. To determine the relative contribution and the nature of γδ T-cell receptor-positive T cells in newborns, compared to CD4+ T cells, in immunity induced by M. bovis BCG vaccination, 4-week-old specific-pathogen-free pigs were vaccinated with M. bovis BCG and monitored by following the γδ T-cell immune responses. A flow cytometry-based proliferation assay and intracellular staining for gamma interferon (IFN-γ) were used to examine γδ T-cell responses. Pigs were found to mount Th1-like responses to M. bovis BCG vaccination as determined by immunoproliferation and IFN-γ production. The γδ T-cell lymphoproliferation and IFN-γ production to stimulation with mycobacterial antigens were significantly enhanced by M. bovis BCG vaccination. The relative number of proliferating γδ T cells after stimulating peripheral blood mononuclear cells with Mycobacterium tuberculosis H37Rv culture filtrate protein was higher than that of CD4+ T cells at an early time point after M. bovis BCG vaccination, but CD4+ T cells were found to be more abundant at a later time point. Although the γδ T-cell responses were dependent on the presence of CD4+ T cells for the cytokine interleukin-2, the enhanced γδ T cells were due to the intrinsic changes of γδ T cells caused by M. bovis BCG vaccination rather than being due solely to help from CD4+ T cells. Our study shows that γδ T cells from pigs at early ages are functionally enhanced by M. bovis BCG vaccination and suggests an important role for this T-cell subset in acquired immunity conferred by M. bovis BCG vaccination.

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Role of Thymic Output in Regulating CD8 T-Cell Homeostasis during Acute and Chronic Viral Infection

Journal of Virology ◽

10.1128/jvi.79.15.9419-9429.2005 ◽

2005 ◽

Vol 79 (15) ◽

pp. 9419-9429 ◽

Cited By ~ 29

Author(s):

Nicole E. Miller ◽

Jennifer R. Bonczyk ◽

Yumi Nakayama ◽

M. Suresh

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cell Response ◽

Viral Infections ◽

T Cell Responses ◽

Cd8 T Cell ◽

T Cell Response ◽

Cell Responses ◽

Lcmv Infection

ABSTRACT Although it is well documented that CD8 T cells play a critical role in controlling chronic viral infections, the mechanisms underlying the regulation of CD8 T-cell responses are not well understood. Using the mouse model of an acute and chronic lymphocytic choriomeningitis virus (LCMV) infection, we have examined the relative importance of peripheral T cells and thymic emigrants in the elicitation and maintenance of CD8 T-cell responses. Virus-specific CD8 T-cell responses were compared between mice that were either sham thymectomized or thymectomized (Thx) at ∼6 weeks of age. In an acute LCMV infection, thymic deficiency did not affect either the primary expansion of CD8 T cells or the proliferative renewal and maintenance of virus-specific lymphoid and nonlymphoid memory CD8 T cells. Following a chronic LCMV infection, in Thx mice, although the initial expansion of CD8 T cells was normal, the contraction phase of the CD8 T-cell response was exaggerated, which led to a transient but striking CD8 T-cell deficit on day 30 postinfection. However, the virus-specific CD8 T-cell response in Thx mice rebounded quickly and was maintained at normal levels thereafter, which indicated that the peripheral T-cell repertoire is quite robust and capable of sustaining an effective CD8 T-cell response in the absence of thymic output during a chronic LCMV infection. Taken together, these findings should further our understanding of the regulation of CD8 T-cell homeostasis in acute and chronic viral infections and might have implications in the development of immunotherapy.

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DNA gag/Adenovirus Type 5 (Ad5) gag and Ad5 gag/Ad5 gag Vaccines Induce Distinct T-Cell Response Profiles

Journal of Virology ◽

10.1128/jvi.00620-08 ◽

2008 ◽

Vol 82 (16) ◽

pp. 8161-8171 ◽

Cited By ~ 40

Author(s):

Kara S. Cox ◽

James H. Clair ◽

Michael T. Prokop ◽

Kara J. Sykes ◽

Sheri A. Dubey ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Response ◽

T Cell Responses ◽

Adenovirus Type ◽

T Cell Response ◽

Cell Responses ◽

Response Profiles ◽

Adenovirus Type 5 ◽

Hiv 1

ABSTRACT Results from Merck's phase II adenovirus type 5 (Ad5) gag/pol/nef test-of-concept trial showed that the vaccine lacked efficacy against human immunodeficiency virus (HIV) infection in a high-risk population. Among the many questions to be explored following this outcome are whether (i) the Ad5 vaccine induced the quality of T-cell responses necessary for efficacy and (ii) the lack of efficacy in the Ad5 vaccine can be generalized to other vector approaches intended to induce HIV type 1 (HIV-1)-specific T-cell responses. Here we present a comprehensive evaluation of the T-cell response profiles from cohorts of clinical trial subjects who received the HIV CAM-1 gag insert delivered by either a regimen with DNA priming followed by Ad5 boosting (n = 50) or a homologous Ad5/Ad5 prime-boost regimen (n = 70). The samples were tested using a statistically qualified nine-color intracellular cytokine staining assay measuring interleukin-2 (IL-2), tumor necrosis factor alpha, macrophage inflammatory protein 1β, and gamma interferon production and expression of CD107a. Both vaccine regimens induced CD4+ and CD8+ HIV gag-specific T-cell responses which variably expressed several intracellular markers. Several trends were observed in which the frequencies of HIV-1-specific CD4+ T cells and IL-2 production from antigen-specific CD8+ T cells in the DNA/Ad5 cohort were more pronounced than in the Ad5/Ad5 cohort. Implications of these results for future vaccine development will be discussed.

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The Polyomavirus BK Large T-Antigen-Derived Peptide Elicits an HLA-DR Promiscuous and Polyfunctional CD4+T-Cell Response

Clinical and Vaccine Immunology ◽

10.1128/cvi.00487-10 ◽

2011 ◽

Vol 18 (5) ◽

pp. 815-824 ◽

Cited By ~ 17

Author(s):

Bala Ramaswami ◽

Iulia Popescu ◽

Camila Macedo ◽

Chunqing Luo ◽

Ron Shapiro ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

T Cell ◽

Cell Response ◽

T Antigen ◽

T Cell Response ◽

Peptide Sequence ◽

Large T Antigen ◽

Hla Dr ◽

Ifn Γ

ABSTRACTBK virus (BKV) nephropathy and hemorrhagic cystitis are increasingly recognized causes of disease in renal and hematopoietic stem cell transplant recipients, respectively. Functional characterization of the immune response to BKV is important for clinical diagnosis, prognosis, and vaccine design. A peptide mix (PepMix) and overlapping (OPP) or random (RPP) peptide pools derived from BKV large T antigen (LTA) were used to restimulate 14-day-expanded peripheral blood mononuclear cells (PBMC) from 27 healthy control subjects in gamma interferon (IFN-γ)-specific enzyme-linked immunospot (ELISPOT) assays. A T-cell response to LTA PepMix was detected in 15/27 subjects. A response was frequently observed with peptides derived from the helicase domain (9/15 subjects), while the DNA binding and host range domains were immunologically inert (0/15 subjects). For all nine subjects who responded to LTA peptide pools, the immune response could be explained largely by a 15-mer peptide designated P313. P313-specific CD4+T-cell clones demonstrated (i) stringent LTA peptide specificity; (ii) promiscuous recognition in the context of HLA-DR alleles; (iii) cross recognition of homologous peptides from the polyomavirus simian virus 40 (SV40); (iv) an effector memory phenotype, CD107a expression, and intracellular production of IFN-γ and tumor necrosis factor alpha (TNF-α); (v) cytotoxic activity in a chromium release assay; and (vi) the ability to directly present cognate antigen to autologous T cells. In conclusion, T-cell-mediated immunity to BKV in healthy subjects is associated with a polyfunctional population of CD4+T cells with dual T-helper and T-cytotoxic properties. HLA class II promiscuity in antigen presentation makes the targeted LTA peptide sequence a suitable candidate for inclusion in immunotherapy protocols.

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Activation-induced Markers Detect Vaccine-Specific CD4+ T Cell Responses Not Measured by Assays Conventionally Used in Clinical Trials

Vaccines ◽

10.3390/vaccines6030050 ◽

2018 ◽

Vol 6 (3) ◽

pp. 50 ◽

Cited By ~ 6

Author(s):

Georgina Bowyer ◽

Tommy Rampling ◽

Jonathan Powlson ◽

Richard Morter ◽

Daniel Wright ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cell Response ◽

Viral Vectors ◽

Comprehensive Evaluation ◽

T Cell Responses ◽

T Cell Response ◽

Cell Responses ◽

Vaccine Immunogenicity ◽

Sensitivity Specificity

Immunogenicity of T cell-inducing vaccines, such as viral vectors or DNA vaccines and Bacillus Calmette-Guérin (BCG), are frequently assessed by cytokine-based approaches. While these are sensitive methods that have shown correlates of protection in various vaccine studies, they only identify a small proportion of the vaccine-specific T cell response. Responses to vaccination are likely to be heterogeneous, particularly when comparing prime and boost or assessing vaccine performance across diverse populations. Activation-induced markers (AIM) can provide a broader view of the total antigen-specific T cell response to enable a more comprehensive evaluation of vaccine immunogenicity. We tested an AIM assay for the detection of vaccine-specific CD4+ and CD8+ T cell responses in healthy UK adults vaccinated with viral vectored Ebola vaccine candidates, ChAd3-EBO-Z and MVA-EBO-Z. We used the markers, CD25, CD134 (OX40), CD274 (PDL1), and CD107a, to sensitively identify vaccine-responsive T cells. We compared the use of OX40+CD25+ and OX40+PDL1+ in CD4+ T cells and OX40+CD25+ and CD25+CD107a+ in CD8+ T cells for their sensitivity, specificity, and associations with other measures of vaccine immunogenicity. We show that activation-induced markers can be used as an additional method of demonstrating vaccine immunogenicity, providing a broader picture of the global T cell response to vaccination.

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Safety Profile of a Virus-Like Particle-Based Vaccine Targeting Self-Protein Interleukin-5 in Horses

Vaccines ◽

10.3390/vaccines8020213 ◽

2020 ◽

Vol 8 (2) ◽

pp. 213 ◽

Cited By ~ 4

Author(s):

Sigridur Jonsdottir ◽

Victoria Fettelschoss ◽

Florian Olomski ◽

Stephanie C. Talker ◽

Jelena Mirkovitch ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

B Cell ◽

Mononuclear Cells ◽

Clinical Signs ◽

T Cell Response ◽

Type I ◽

Cell Responses ◽

Virus Like Particle ◽

Ifn Γ

Background: Insect bite hypersensitivity (IBH) is an eosinophilic allergic dermatitis of horses caused by type I/IVb reactions against mainly Culicoides bites. The vaccination of IBH-affected horses with equine IL-5 coupled to the Cucumber mosaic virus-like particle (eIL-5-CuMVTT) induces IL-5-specific auto-antibodies, resulting in a significant reduction in eosinophil levels in blood and clinical signs. Objective: the preclinical and clinical safety of the eIL-5-CuMVTT vaccine. Methods: The B cell responses were assessed by longitudinal measurement of IL-5- and CuMVTT-specific IgG in the serum and plasma of vaccinated and unvaccinated horses. Further, peripheral blood mononuclear cells (PBMCs) from the same horses were re-stimulated in vitro for the proliferation and IFN-γ production of specific T cells. In addition, we evaluated longitudinal kidney and liver parameters and the general blood status. An endogenous protein challenge was performed in murine IL-5-vaccinated mice. Results: The vaccine was well tolerated as assessed by serum and cellular biomarkers and also induced reversible and neutralizing antibody titers in horses and mice. Endogenous IL-5 stimulation was unable to re-induce anti-IL-5 production. The CD4+ T cells of vaccinated horses produced significantly more IFN-γ and showed a stronger proliferation following stimulation with CuMVTT as compared to the unvaccinated controls. Re-stimulation using E. coli-derived proteins induced low levels of IFNγ+CD4+ cells in vaccinated horses; however, no IFN-γ and proliferation were induced following the HEK-eIL-5 re-stimulation. Conclusions: Vaccination using eIL-5-CuMVTT induces a strong B-cell as well as CuMVTT-specific T cell response without the induction of IL-5-specific T cell responses. Hence, B-cell unresponsiveness against self-IL-5 can be bypassed by inducing CuMVTT carrier-specific T cells, making the vaccine a safe therapeutic option for IBH-affected horses.

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