Immunomagnetic Depletion of CD25-Expressing T Cells from Donor Blood Removes a Mixed Population of Regulatory and Effector T Cells - Implications for Graft Engineering.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 724-724
Author(s):  
J. Joseph Melenhorst ◽  
Jun Lu ◽  
Edgardo Sosa ◽  
Nancy F. Hensel ◽  
A. John Barrett
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Substantial Proportion ◽  
Absolute Increase ◽  
Cell Responses ◽  
Treg Population

Abstract CD4+CD25+FOXP3+ regulatory T cells (TR) control proliferative CD4 and CD8 T cell responses to self and foreign antigens such as cytomegalovirus (CMV) and tumor-specific antigens. Thus, depletion of CD25-expressing cells from a resting population of T cells prior to antigen stimulation could boost the generation of antigen-specific T cells for adoptive transfer to treat viral infection or tumors. We depleted peripheral blood mononuclear cells (PBMC) from nine CMV seropositive donors using Miltenyi CD25 microbeads (20 μl/107 cells). CD25-depleted or unmanipulated PBMC were stimulated with CMV pp65-expressing antigen presenting cells for 10–14 days with low dose IL-2, and intracellular interferon-gamma (IFNγ) production by flow cytometry was compared between CD25-depleted and -undepleted cultures. An absolute increase in antigen-specific CD4+ and CD8+ T cells was seen after CD25 depletion in 4/8 and 5/8 cultures respectively. However, in other cultures there was a decrease or no change in IFNγ+ CD4+ T cells in CD25-depleted cultures, suggesting that the pp65-specific precursor cells had also been removed. We then used 4 μl beads per 107 PBMC to selectively remove only the CD25bright (predominantly Treg) population in nine donors and confirmed by flow cytometry that only CD25bright cells had been removed from the starting population. However, real-time quantitative PCR (Q-PCR) showed that even though the CD25+ fraction was enriched in FOXP3-expressing cells, a substantial proportion of the CD25-depleted PBMC still expressed FOXP3. Flow cytometric analysis of FOXP3 expression by CD25+ and CD25-negative CD4+ T cells showed that a substantial proportion of CD25- cells expressed FOXP3, confirming that CD25 is not a suitable single marker for depletion of Tregs. Again no reproducible augmentation of antigen-specific T cell responses was observed: one and five donors showing an increase in CD4 and CD8+ antigen-specific T cells, respectively, while the remainder showed a decrease or no change in CD4+ and CD8+ IFNγ-producing cells. These results suggest that removal of CD25+ cells from PBMC using CD25 microbeads removes both Treg and pp65-specific effector CD4+ and CD8+ T cells. Further, since FOXP3 is induced in responder cells as confirmed by FOXP3 Q-PCR, depletion of Treg at the start of the cultures may only transiently alleviate the negative regulation of the antigen response. Thus, CD25 depletion using microbeads is not a reliable method to boost antigen specific T cell expansions because of the inadvertent removal of a portion of the memory response to the antigen. Since it recently has been demonstrated that Treg act as an IL-2 sink, the addition of this cytokine should functionally silence the Tregs while preserving the inflammatory response.

BK Polyomavirus–Specific CD8 T-Cell Expansion In Vitro Using 27mer Peptide Antigens for Developing Adoptive T-Cell Transfer and Vaccination

2020 ◽  
Author(s):  
Maud Wilhelm ◽  
Amandeep Kaur ◽  
Marion Wernli ◽  
Hans H Hirsch
Keyword(s):  
T Cells ◽  
T Cell ◽  
Kidney Transplant ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Bk Polyomavirus

Abstract Background BK polyomavirus (BKPyV) remains a significant cause of premature kidney transplant failure. In the absence of effective antivirals, current treatments rely on reducing immunosuppression to regain immune control over BKPyV replication. Increasing BKPyV-specific CD8 T cells correlate with clearance of BKPyV DNAemia in kidney transplant patients. We characterized a novel approach for expanding BKPyV-specific CD8 T cells in vitro using 27mer-long synthetic BKPyV peptides, different types of antigen-presenting cells, and CD4 T cells. Methods Langerhans cells and immature or mature monocyte-derived dendritic cells (Mo-DCs) were generated from peripheral blood mononuclear cells of healthy blood donors, pulsed with synthetic peptide pools consisting of 36 overlapping 27mers (27mP) or 180 15mers (15mP). BKPyV-specific CD8 T-cell responses were assessed by cytokine release assays using 15mP or immunodominant 9mers. Results BKPyV-specific CD8 T cells expanded using 27mP and required mature Mo-DCs (P = .0312) and CD4 T cells (P = .0156) for highest responses. The resulting BKPyV-specific CD8 T cells proliferated, secreted multiple cytokines including interferon γ and tumor necrosis factor α, and were functional (CD107a+/PD1–) and cytotoxic. Conclusions Synthetic 27mP permit expanding BKPyV-specific CD8 T-cell responses when pulsing mature Mo-DCs in presence of CD4 T cells, suggesting novel and safe approaches to vaccination and adoptive T-cell therapies for patients before and after kidney transplantation.

Peptide-Induced Antigen-Specific CD4+CD25+FoxP3+ T Cells Suppress Cytotoxicity T Cell Responses Directed Against the AAV Capsid.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3769-3769 ◽  
Author(s):  
Daniel J. Hui ◽  
Etiena Basner-Tschakarjan ◽  
Gary C. Pien ◽  
William D. Martin ◽  
Annie S. DeGroot ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Gene Transfer ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Equity Ownership

Abstract Abstract 3769 Recent advances in adeno-associated viral (AAV) vector-mediated gene transfer continue to offer hope for the correction of monogenic disorders such as hemophilia B. However, unanticipated T cell responses directed against viral capsid epitopes may limit the efficacy of AAV gene transfer. A phase I clinical study in which an AAV2 vector expressing human factor IX (FIX) was delivered systemically provided the first evidence that AAV vector administration at high doses may trigger the expansion of memory CD8+ T cells directed against AAV capsid epitopes. This response was associated with the loss of FIX transgene expression and a transient increase in liver enzymes. Additional studies in human subjects undergoing AAV gene transfer suggest that the capsid antigen load is an important determinant of capsid-specific T cell activation. Thus, strategies for the modulation of capsid T cell responses could contribute to achieving sustained transgene expression following high dose delivery of AAV. MHC class II peptide ligands identified within the human IgG Fc fragment (Tregitopes, Blood 2008;112:3303) have been shown to expand regulatory T cells (Tregs). Restimulation of human peripheral blood mononuclear cells (PBMC) in vitro with AAV capsid antigen in the presence of Tregitopes resulted in the suppression of capsid-specific CD8+ T cells and in the expansion of CD4+CD25+FoxP3+ Tregs. To better define the nature of Tregitope-induced Tregs, we depleted CD25+ cells from PBMC prior to in vitro restimulation. This completely prevented capsid-specific CTL suppression and the expansion of Tregs, suggesting that Tregitopes act by expanding natural Tregs. Cytokine ELISA on conditioned media from PBMC co-cultured with AAV antigen and Tregitopes showed a 50% decrease in IL-2 levels and a >500-fold increase in IL-10 levels. These results suggest that the effect of Tregitopes may be cytokine mediated. To test this hypothesis, we used a transwell system in which the CD4+ T cell fraction of Tregitope-restimulated PBMC was co-cultured with the capsid-specific CD8+ T cells. Without cell contact, a nearly 50% suppression of anti-capsid CD8+ T cell responses was observed. Further evidence supporting the role of cytokine-mediated suppression came from the observation that Tregitope-treated capsid-specific CD8+ T cells appeared to be anergic, and depletion of CD4+ T cells (Tregs) followed by a 24-hour incubation of CD8+CD4− T cells with IL-2 restored >80% of CTL activity. Finally, antigen specificity of Tregitope-induced Tregs was tested by expanding PBMC in vitro with HLA-B*0702-restricted epitopes from either the AAV capsid or the Epstein-Barr Virus (EBV). After in vitro restimulation, negatively-isolated CD4+ T cells expanded in the presence of EBV antigen and Tregitopes were co-incubated with either CD8+ T cells expanded against the AAV capsid or against EBV. Suppression of CTL activity was observed only when EBV Tregs were co-incubated with EBV CD8+ T cells. Similarly, Tregs isolated from AAV and Tregitope cultures suppressed AAV-specific CD8+ T cells but not EBV-specific CD8+T cells. These results suggest that inhibition of CD8+ T cell responses is antigen-specific. We conclude that Tregitopes induce the expansion of Tregs, which can mediate a potent antigen-specific inhibition of CD8+ T cell responses directed to the AAV capsid. Disclosures: Hui: Children's Hospital of Philadelphia: Patents & Royalties. Martin:EpiVax: Employment, Equity Ownership, Patents & Royalties. DeGroot:EpiVax: Employment, Equity Ownership. High:Children's Hospital of Philadelphia: Patents & Royalties. Mingozzi:Children's Hospital of Philadelphia: Patents & Royalties.

scholarly journals CD40-deficient, Influenza-specific CD8 Memory T Cells Develop and Function Normally in a CD40-sufficient Environment

2003 ◽  
Vol 198 (11) ◽  
pp. 1759-1764 ◽  
Author(s):  
Byung O. Lee ◽  
Louise Hartson ◽  
Troy D. Randall
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Inflammatory Responses ◽  
Classical Model ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cd8 Cells ◽  
Cell Responses

Two models have been proposed to explain the requirement for CD40 signaling in CD8 T cell responses. The first model suggests that CD4 T cells activate antigen-presenting cells (APCs) through CD40 signaling (APC licensing). In turn, licensed APCs are able to prime naive CD8 T cells. The second model suggests that CD154-expressing CD4 T cells activate CD40-bearing CD8 T cells directly. Although the requirement for CD40 in APC licensing can be bypassed by inflammatory responses to pathogens that activate APCs directly, the second model predicts that CD8 responses to all antigens will be dependent on CD40 signaling. Here we determined which model applies to CD8 responses to influenza. We demonstrate that optimal CD8 T cell responses to influenza are dependent on CD40 signaling, however both primary and secondary responses to influenza require CD40 expression on non–T cells. Furthermore, CD40−/− CD8 T cells proliferate and differentiate to the same extent as CD40+/+ CD8 T cells in response to influenza, as long as they have equal access to CD40+/+ APCs. Thus, CD4 T cells do not activate influenza-specific CD8 cells directly through CD40 signaling. Instead, these data support the classical model, in which CD4 T cells provide help to CD8 T cells indirectly by activating APCs through CD40.

The Mutated Region of Cytoplasmatic Nucleophosmine 1 (NPM1) Elicits Both CD4+ and CD8+ T Cell Responses

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2569-2569
Author(s):  
Jochen Greiner ◽  
Yoko Ono ◽  
Susanne Hofmann ◽  
Vanessa Schneider ◽  
Anita Schmitt ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Healthy Volunteers ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Granzyme B ◽  
T Cell Responses ◽  
Interferon Γ ◽  
Cell Responses ◽  
Hla Dr

Abstract Abstract 2569 Introduction In AML, mutations in the nucleophosmin (NPM1) gene are one of the most frequent molecular alterations and predominantly occur in AML with normal cytogenetics. Patients with NPM1 mutation without FLT3-ITD mutation show a favourable prognosis of their disease. The functional role of mutated NPM1 for the improved clinical outcome is under evaluation. Immune responses might be involved in the clinical outcome of the disease. In this work, we demonstrate both CD4+ and CD8+ T cell responses against the mutated region of NPM1. Methods The entire amino acid sequences of the NPM1 wild type protein as well as of the mutated cytoplasmic NPM1 types A, B, C and D were screened for HLA-A*0201 binding T cell epitopes using the algorithms of the SYFPEITHI, the Rankpep and the HLA-Bind software programs. Ten peptides with most favourable characteristics were subjected to ELISpot analysis for interferon-γ and granzyme B in 22 healthy volunteers and 27 AML patients to test specific T cell responses of CD8+ T cells. Tetramer assays against the two most interesting epitopes have been performed and chromium release assays have been used to show the cytotoxicity of peptide-specific T cells to lyse T2 cells and leukemic blasts. Moreover, HLA-DR binding epitopes were screened in algorithmic analysis and HLA-DR*0701 binding peptides were exploited to stimulate CD4+ T cells. In the presence of overlapping peptide stimulated CD4+ T cells, NPM1-A specific CD8+ T cells revealed augmented interferon-γ and granzyme B secretion and up-regulation of intracellular interferon-γ. CD4+, CD4-CD8+, CD4-CD8- cell fractions were separated from PBMCs of HLA-A2+DR*0701+ healthy volunteers using a combination of CD4 and CD8 MicroBeads. Results Two epitopes (P3 and P9) derived from the NPM1-mutated protein showed specific T cell responses in healthy volunteers and AML patients. In NPM1-mutated AML patients 33% showed immune responses of CD8+ T cells against peptide P3 and 42% against peptide P9. Specific lysis was detected in chromium release assays NPM1 peptide-primed effector T cells generated from NPM1-mutated AML patients. Tetramer assays showed peptide-specific T cells. To obtain a robust and effective immune response against tumor cells, the activation of CD4 + helper T cells is crucial. Thus NPM1-peptide-A overlapping MHC class II epitopes were searched by primary structure analysis program. Based on plenary search, eight favourable overlapping peptides OL 1–8 were synthesized and exploited for CD4+ T cell stimulation. In granzyme B ELISPOT assay, OL8 co-pulsed NPM1-A CD8+ T cells indicated notable S.I., in contrast other OL1-7 disabled to increase granzyme B secretion. To ensure that Th1 cytokine secretion, under the condition of CD8+ and CD4+ T cells mixed culture, was resulted from NPM1-A CD8+ T cells but not HLA-DR epitope stimulated CD4+ T cells activation, HLA-A2 blocking effect was confirmed in ELISPOT assay. NPM1-A CD8+ T cells co-pulsed with OL6, 7 and 8 showed lesser interferon-γ secretion after HLA-A2 blocking antibody exposure as 73, 35 and 57%. Of note, 83–94% of granzyme B secretion levels were reduced by HLA-A2 blockade administration, and by which NPM1-A CD8+ T cells seemed to be the most probable IFN-gamma and granzyme B producers and CD4+ T cells to interfere with CD8+ T cells. Conclusion Taken together, mutated NPM1 is a promising target structure for specific immunotherapies in AML patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Role for Inducible Costimulator in Control of Salmonella enterica Serovar Typhimurium Infection in Mice

2006 ◽  
Vol 74 (2) ◽  
pp. 1050-1061 ◽  
Author(s):  
Mariana Vidric ◽  
Anna Tafuri Bladt ◽  
Umberto Dianzani ◽  
Tania H. Watts
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Salmonella Enterica ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Inducible Costimulator ◽  
Serovar Typhimurium

ABSTRACT Inducible costimulator (ICOS) is expressed on activated T cells and plays a key role in sustaining and enhancing the effector function of CD4 T cells. Given the function of this molecule in sustaining T-cell responses, we reasoned that ICOS might play an important role in a prolonged infection model, such as Salmonella infection of mice. To test this hypothesis, wild-type (WT) and ICOS-deficient (ICOS−/−) mice were infected systemically with a Salmonella enterica serovar Typhimurium strain expressing the chicken ovalbumin gene (Salmonella-OVA). ICOS−/− mice exhibited greater splenomegaly than WT mice and showed delayed bacterial clearance. The acquired immune response in this model was slow to develop. Maximal T-cell responses to Salmonella-OVA were detected at 3 weeks postinfection in both WT and ICOS−/− mice. CD4 T-cell-dependent gamma interferon production and a class switch to immunoglobulin G2a were severely reduced in ICOS−/− mice. ICOS−/− mice also exhibited a substantial defect in antigen-specific CD8 T-cell responses. In vitro, the effect of anti-ICOS on CD8 T-cell division was greater when CD8 T cells rather than CD4 T cells expressed ICOS, suggesting that the in vivo effects of ICOS on CD8 T cells could be direct. Taken together, these studies show that ICOS plays a critical role in control of Salmonella infection in mice, with effects on antibody, Th1, and CD8 T-cell responses.

scholarly journals Evaluation of Virus-Specific T Cell Responses in Patients Affected with Myeloproliferative Neoplasms Treated with Ruxolitinib

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1660-1660 ◽  
Author(s):  
Elisa Rumi ◽  
Chiara Cavalloni ◽  
Giuditta Comolli ◽  
Virginia Valeria Ferretti ◽  
Irene Cassaniti ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Inverse Correlation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
P Values ◽  
Cell Responses ◽  
Ebv Dna

Background The classic Ph-negative myeloproliferative neoplasms (MPN) are a group of clonal haematopoietic disorders, including polycythemia vera (PV), essential thrombocythemia (ET) and myelofibrosis (MF) (either primary or secondary), that share the deregulation of JAK-STAT signalling. Over the past few years, there have been significant changes in the therapeutic landscape of MPN, thanks to the approval of the JAK-inhibitor ruxolitinib. Despite its efficacy and beyond its well described haematological toxicity, the drug may also cause an increased risk of reactivation of silent infections (e.g., tuberculosis, hepatitis B virus and varicella zoster virus). Less is known regarding other opportunistic viral pathogens, such as human cytomegalovirus (HCMV) and Epstein-Barr virus (EBV). The aim of this study was to evaluate the viral load and T cell responses to HCMV and EBV in 25 MPN patients (6 PV, 5 ET, 14 MF) treated with ruxolitinib. Methods Peripheral blood was collected monthly for viral genome quantification using real-time PCR (EBV-DNA and HCMV-DNA) and determination of T cell subsets by flow cytometry (absolute number of CD3+, CD3+CD4+, and CD3+CD8+). The T cell responses specific to HCMV and EBV were evaluated monthly using IFN-γ ELISPOT assay. Results were normalized to CD4+ and CD8+ T cell count. Correlations between T cell responses were evaluated by regression models for panel data (with random or fixed effects based on result of Hausman test). P-values <0.05 were considered significant. Results Of 25 patients treated with Ruxolitinib (median time of treatment: 5 years, range: 0.2-10.5 years), 15 (60%) had CD4+ T cells and 7 (28%) had CD8+ T cells below normal ranges. The reduction was observed in all MPN subtypes: CD4+ T cells were reduced in 50% of PV, 80% of ET, 57% of MF; CD8+ T cells were reduced in 33% of PV, 60% of ET and 14% of MF. The reduction was not different based on disease duration (<10 years vs >= 10 years since diagnosis) while it correlated with duration of ruxolitinib treatment: patients receiving ruxolitinib for more than 5 years had more frequently a reduction of CD4+ T cells and/or CD8+ T cells compared with patients treated for less than 5 years (93% vs 45% P 0.021). Moreover, the median number of CD4+ cells and CD8+ cells were lower in patients treated >= 5 years vs <5 years (366 vs 558 cells/μl P = 0.043 and 206 vs 365 cells/μl P = 0.002). During the study, reactivation of EBV was observed in 76% of patients while only 8% experienced reactivations of HCMV ; only one patient (4%) experienced Varicella Zoster Virus clinical reactivation. Both the EBV-specific and CMV-specific CD4+ and CD8+ T cell responses showed an inverse correlation with detectable EBV DNA and HCMV DNA although it was not statistically significant (all p-values>0.2). When normalizing results to CD4 and CD8 T cell counts we observed again an inverse correlation without statistical significance (all p-values>0.1). Both the EBV-specific and CMV-specific CD4+ and CD8+ T cell responses had an inverse correlation with the dosage of ruxolitinib (<= 20 mg/die vs > 20 mg/die) although not statistically significant (all p-values>0.06). Conclusions Our study suggests that a reduction of CD4+ T cells and CD8+ T cells is frequently observed in MPN patients treated with ruxolitinib and is associated with treatment duration (>= 5 years vs <5 years). Reactivation of EBV occurs frequently while reactivation of CMV is less frequent. As the virus-specific T cell responses seem to have a trend to an inverse correlation with detectable EBV DNA and HCMV DNA we hypothesize that an impaired response makes the patient unable to clear the virus. Moreover, the virus-specific T cell responses seem to have a trend to an inverse correlation with ruxolitinib dosage, thus pointing to a potential role of the drug in favouring viral reactivation. To corroborate this hypothesis, virus-specific T cell responses need to be analysed in a larger number of patients with MPN under ruxolitinib treatment. Disclosures Rumi: novartis: Honoraria, Research Funding. Arcaini:Gilead Sciences: Research Funding; Celgene: Speakers Bureau; Bayer, Celgene, Gilead Sciences, Roche, Sandoz, Janssen-Cilag, VERASTEM: Consultancy; Celgene, Roche, Janssen-Cilag, Gilead: Other: Travel expenses.

857 LAMP1 targeting of the large T antigen of merkel cell polyomavirus elicits potent CD4+ T cell responses and prevents tumor growth

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A910-A910
Author(s):  
Claire Buchta Rosean ◽  
Claire Buchta Rosean ◽  
Pratima Sinha ◽  
David Koelle ◽  
Paul Nghiem ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
T Antigen ◽  
T Cell Response ◽  
Cd4 T Cell ◽  
Merkel Cell ◽  
Cell Responses

BackgroundThe majority of Merkel cell carcinomas (MCC), a rare and highly-aggressive type of neuroendocrine skin cancer, are associated with Merkel cell polyomavirus (MCPyV) infection. MCPyV integrates into the host genome, resulting in expression of a truncated form of the viral large T antigen (LT) in infected cells, and making LT an attractive target for therapeutic cancer vaccines. While induction of tumor-reactive CD8+ T cells is a major goal of cancer therapy, CD4+ T cells provide essential support to CD8+ T cells by promoting their expression of cytotoxic effector molecules and increasing their migratory capacity. Cytokines secreted by CD4+ T cells, such as IFNγ, can also exert desirable effects on the tumor microenvironment. Therefore, we set out to design a cancer vaccine that promotes potent, antigen-specific CD4+ T cell responses to MCPyV-LT.MethodsTo activate antigen-specific CD4+ T cells in vivo, we utilized our nucleic acid platform, UNITE (UNiversal Intracellular Targeted Expression), which fuses a tumor-associated antigen with lysosomal-associated membrane protein 1 (LAMP1). This lysosomal targeting technology results in enhanced antigen presentation and a balanced T cell response. LTS220A, encoding a mutated form of MCPyV-LT that abrogates its pro-oncogenic properties, was introduced into the UNITE platform. LTS220A-UNITE, known as ITI-3000, was administered to female C57BL/6 mice intradermally in the ear with electroporation.ResultsITI-3000 promoted a potent, antigen-specific CD4+ T cell response to MCPyV-LT. Vaccination with ITI-3000 significantly delayed and slowed growth of B16F10 tumors expressing LTS220A in prophylactic and therapeutic settings, respectively. ITI-3000 induced a favorable tumor microenvironment (TME), including significantly enhanced numbers of CD4+ T cells, CD8+ T cells, NK cells, and NKT cells. Tumor-infiltrating myeloid cells were reduced in frequency in vaccinated mice and polarized towards an anti-tumor phenotype. Cytokine analysis of the TME showed significantly enhanced levels of cytokines associated with anti-tumor immune responses in ITI-3000-vaccinated mice, including IFNγ, TNFα, IL-2, and IL-1β. Additionally, ITI-3000 synergized with PD-1 blockade, further reducing tumor burden and enhancing survival in mice receiving combination therapy.ConclusionsWe find that DNA vaccination with ITI-3000 using the UNITE platform enhances CD4+ T cell responses to MCPyV-LT and results in anti-tumor immune responses in a mouse model of Merkel cell carcinoma.Ethics ApprovalThis study was approved by Immunomic Therapeutics’ Institutional Animal Care and Use Committee, protocol number 16-11-002.

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

2016 ◽  
Vol 162 ◽  
pp. 91-99 ◽  
Author(s):  
Martine A. Boks ◽  
Judith R. Kager-Groenland ◽  
S. Marieke van Ham ◽  
Anja ten Brinke
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Regulatory Gene ◽  
T Cell Responses ◽  
Gene Profile ◽  
Cell Responses

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

2005 ◽  
Vol 79 (15) ◽  
pp. 9419-9429 ◽  
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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