CD4+ Perforin+ T Cells in B-CLL: MHC Class II Restriction and Anti-Cytomegalovirus Reactivity.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4979-4979
Author(s):  
James Walton ◽  
Keirissa Lawson ◽  
Maria S. Manoussaka ◽  
Amit Nathwani ◽  
Vincent Emory ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Cell Expansion ◽  
Class Ii ◽  
Cd4 Cells ◽  
Hla Dr ◽  
Ifn Γ ◽  
T Cell Expansion

Abstract Introduction: An expansion of CD4+ T cells expressing perforin (PF) has recently been described in B-CLL and we have previously demonstrated anti-cytomegalovirus (CMV) reactivity within this population (Walton et al; 2004; Blood [ASH annual meeting abstracts] 104:4787). Here we further characterise the anti-CMV response of CD4+PF+ T cells in B-CLL and investigate the role of CMV in CD4+PF+ T cell expansion. Methods: Peripheral blood mononuclear cells (PBMC’s) from 24 untreated B-CLL patients (17 CMV seropositive [SP], 7 CMV seronegative [SN]), 2 SP treated (Campath) patients and 12 healthy age-matched control individuals (8 SP, 4 SN) were fixed, permeabilised and stained with anti-CD4PerCP, anti-IFN-γ-APC and anti-PF-FITC monoclonal antibodies (mABs) (BD). PBMC were cultured for 18 hrs with DOWNE cell lysate (Dade Behring) containing CMV-antigen or lysate alone and with anti-CD28 and anti-CD49d mAbs (BD), in the presence of Brefeldin A (eBiosciences). In blocking experiments PBMC were pre-incubated with anti-HLA DR,DP,DQ mAb (BD) for 1 hour. The CMV specific response was assessed by flow cytometry (Dako Cyan, Summit software) as the percentage of IFN-γ+ cells in PF+ and PF− CD4+ T cell populations. Statistical analysis was performed using the Mann-Whitney U test and Spearman rank correlation. Results: The proportion of CD4+ T cells expressing PF directly ex vivo was significantly higher in SP B-CLL patients (17.5±18.6%) compared to SN patients (2.0±2.3%, p=0.019). In seropositive aged matched controls the percentage of CD4+ cells expressing perforin was positively correlated with the percentage of CMV-reactive CD4+ cells (r=0.976, p<0.01). In contrast, there was no significant correlation in the patient group. However, two patients with relatively large expansions of CD4+PF+ cells (37.7±3.39%) post-Campath treatment had high percentages of CMV-reactive CD4+ cells (10.93±0.62%) compared to SP B-CLL patients (1.34±1.19%) and SP controls (1.31±1.14%), implying Campath related CMV reactivation. The addition of anti-HLA-DR,DP,DQ mAb to patients’ PBMCs, prior to CMV stimulation, led to an 80% (from 3.26% to 0.79%) and 90% (from 3.9% to 0.45%) reduction in the proportion of antigen reactive CD4+ and CD4+PF+ cells respectively. Conclusions: A population of major histocompatibility complex (MHC) class II restricted, CMV reactive, CD4+PF+ T cells exists peripherally, in a large group of CMV SP B-CLL patients. Furthermore, CMV is associated with CD4+PF+ T cell expansion in patients and controls. Our data implies that high numbers of B-CLL cells inhibit anti-viral effector function, leading to increased viral activity and chronic antigenic exposure, potentially driving CD4+PF+ T cell expansion.

Treatment of Established B16 Murine Melanoma Tumors with Tyrp-1 Specific CD4+ Lymphocytes.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3688-3688
Author(s):  
Pawel Muranski ◽  
Andrea Boni ◽  
Crystal M. Paulos ◽  
Kari R. Irvine ◽  
Paul A. Antony ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Solid Tumors ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Tumor Response ◽  
Class Ii ◽  
B16 Melanoma ◽  
Cd4 Cells

Abstract T-cell mediated response against solid tumors has been mostly associated with CD8+ cytotoxic lymphocytes, which act directly on the MHC class I expressing tumors. In the previously published model, gp-100 melanoma antigen-specific pmel-1 CD8+ T cells required co-administration of IL-2 and vaccine to induce significant regression of poorly immunogenic B16 melanoma in mice. MHC class II restricted CD4+ T-cells (T helpers) may have multiple direct and indirect effects on the immune response, but their role in adoptive cell transfer (ACT) therapy of solid tumors remains mainly undefined and based on highly manipulated models involving foreign antigens. In order to investigate the function of tumor specific CD4+ T-cells we have generated a transgenic mouse expressing a TRP-1 T cell receptor (TCR) directed against class II restricted murine melanocyte differentiation antigen tyrp-1. In vitro expanded TRP1 CD4+ cells secreted Th1-like cytokines upon antigen stimulation and caused direct cytotoxic effect against B16 melanoma. In vivo they mediated a highly effective response against large (>1cm2) B16 melanoma tumors after ACT of as few as 2.5×105 cells/mouse into C57B6 animals, which was associated with a massive tumor infiltration with CD11b+, MAC3+, GR1+ cells. TRP-1 T cells caused partial tumor rejection and prolonged survival in MHC class II−/− hosts implying the ability to directly recognize low level MHC class II on the tumor. This suboptimal effect was significantly enhanced after co-transfer of MHC class II+ APCs into MHC class II−/− hosts allowing for antigen cross- presentation. Interestingly, Rag1−/− hosts, deficient in all T and B lymphocytes, demonstrated excellent initial response to treatment, but were not cured and succumbed to late relapse of the melanoma. Long-term responses were even more impaired in Rag1−/− γc−/− hosts, while complete and durable cure was observed in TCRα−/−, CD4−/− and C57B6 mice, suggesting involvement of other arms of the adaptive immune system. Similarly, co-transfer of 0.1×106 CD4+ TRP-1 cells and 1×106 CD8+ pmel-1 cells resulted in effective tumor regression, while the same numbers of each cells transferred individually were not sufficient to initiate a rejection. Introduction of tumor-specific CD4+ cells therefore eliminates the previously sine qua non need for co-administration of vaccine and IL-2 for effective treatment with CD8+ pmel-1 cells. Overall, we show that antigen-specific CD4+ T cells are highly effective in mediating the anti-tumor response by causing both the direct anti-tumor effect and by activating innate and adaptive arms of the immune system. These findings suggest that CD4+ T helper cells may play a key role in improving efficacy of ACT immunotherapy as central activators of the anti-tumor response.

Wilms Tumor Protein-1-Derived 9-Mer Peptide Induces CD4 T-Cell Responses in an HLA-DR Restricted Manner

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4351-4351
Author(s):  
Shigeo Fuji ◽  
Julia Fischer ◽  
Markus Kapp ◽  
Thomas G Bumm ◽  
Hermann Einsele ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Class Ii ◽  
Hla Class Ii ◽  
Cd4 T Cell ◽  
Cell Responses ◽  
Hla Dr ◽  
Ifn Γ

Abstract Abstract 4351 Wilms‘ tumor protein-1 (WT1) is one of the most investigated tumor-associated antigens (TAA) in hematological malignancies. CD8 T-cell responses against several WT1-derived peptides have been characterized and are known to contribute to disease control after allogeneic hematopoietic stem cell transplantation (HSCT). Also the identification of human leukocyte antigen (HLA) class II-restricted CD4 T-cell epitopes from WT1 is a challenging task of T-cell-based cancer immunotherapy to improve the effectiveness of WT1 peptide vaccination. We found a highly immunogenic WT1 peptide composed of only 9 amino acids having the ability to induce IFN-γ secretion in CD4 T-cells in an HLA DR-restricted manner. This finding is of great interest as it was generally accepted that HLA class II binding peptides are composed of at least 12 amino acids being recognized by CD4 T-cells, whereas HLA class I binding peptides are composed of 8–11 amino acids being recognized by CD8 T-cells (Wang et al Mol. Immunol. 2002). However, both HLA class I and class II molecules bind to primary and secondary peptide anchor motifs covering the central 9–10 amino acids. Thus, considering this common structural basis for peptide binding there is a possibility that the WT1 9-mer peptide binds to HLA class II molecules, and induces CD4 T-cell responses. IFN-γ induction in response to several WT1 9-mer peptides was screened in 24 HLA-A*02:01 positive patients with acute myeloid leukemia or myelodysplastic syndrome after allogeneic HSCT. Responses to one WT1 9-mer peptide were exclusively detected in CD3+CD4+ T-cells of 2 patients after allogeneic HSCT, but not in CD3+CD4+ T-cells of their corresponding HSC donors. CD4+ T-cell responses to this WT1 9-mer peptide exhibited high levels of functional avidity, as IFN-γ induction was detected after stimulation with 100 ng peptide per mL. Peptide-induced IFN-γ production was confirmed with IFN-γ ELISPOT assays and the HLA restriction of the T-cell response was determined by HLA blocking antibodies. The reaction was significantly blocked by anti-pan HLA class II antibody (85 % reduction), but neither by pan-HLA class I nor by anti-HLA A2 antibody. To identify the subtype of HLA class II molecule, blocking assays with antibodies against HLA-DP, HLA-DR and HLA-DQ were performed. IFN-γ induction was completely abrogated by anti-HLA-DR antibody (99 % reduction) (fig 1, p value of unpaired student‘s t-test <0.0001 for the medium control vs anti-pan HLA class II antibody or anti-HLA-DR antibody, respectively). To test whether IFN-γ was exclusively induced in CD4 T cells, CD4 or CD8 T-cells were depleted from PBMC. Whereas CD8 T-cell depletion did not affect IFN-γ induction, CD4 T-cell depletion completely abrogated the WT1 9-mer peptide induced response (fig 2). CD4 T-cells responding to the WT1 9-mer peptide were indicated to be functional cytotoxic T-cells with an effector CD4 T-cell phenotype. Longitudinal analyses demonstrated the persistence and functionality of WT1 9-mer specific CD4 T-cells in PBMC of patients even at day 1368 after allogeneic HSCT. These data indicate for the first time that a TAA-derived 9-mer peptide can induce HLA class II-restricted CD4 T-cell responses. Vaccination with the characterized WT1 9-mer peptide can enhance the induction and maintenance of not only CD4 but also indirect CD8 T-cell responses. Considering that CD4 T-cells play an important role in tumor rejection, the possibility that other TAA-derived 9-mer peptides having the potential to induce CD4 T-cell responses should be explored in other settings of tumor immunology as well to improve vaccination strategies. Disclosures: No relevant conflicts of interest to declare.

Identification of Low Frequency Multiple Novel Aspergillus Fumigatus Specific MHC Class II Epitopes and Rapid Generation of An Aspergillus-Specific T-Cell Product Based On Activation Dependent Expression of CD154.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1170-1170
Author(s):  
Nina Khanna ◽  
Claudia Stuehler ◽  
Sarah Lurati ◽  
Barbara Conrad ◽  
Michaela Kruhm ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Aspergillus Fumigatus ◽  
Cell Lines ◽  
Mhc Class Ii ◽  
Functional Activity ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Cd4 Cells ◽  
Fungal Extracts

Abstract Abstract 1170 Poster Board I-192 Despite new antifungal drugs, invasive aspergillosis (IA) remains a major cause of morbidity and mortality in patients undergoing myeloablative chemotherapy and allogeneic stem cell transplantation. Invasion of Aspergillus sp. in immuncompetent individuals is primarily controlled by neutrophils, phagocytes and pathogen-specific TH1 CD4+ cells. Therefore, adoptive transfer of Aspergillus-specific CD4+ T-cells could protect patients at risk from IA. Favorable candidates for such an approach are GPI-anchored antigens, which have demonstrated induction of protective adaptive immunity in murine studies. To implement Aspergillus-specific CD4+ T-cells into the clinical setting, we aimed (i) to define which GPI-anchored antigen induces TH1 response, (ii) to map several epitopes and (iii) to generate large amounts of Aspergillus-specific TH1 cells within a short period. Several recombinant proteins were either synthesized or were received by J-P Latge. Amongst all tested proteins, only CRF-1 induced repeatedly TH1 response in healthy individuals. To identify Aspergillus-specific MHC class II epitopes, we mapped peripheral blood mononuclear cells (PBMC) of healthy individuals with a custom made peptide library of CRF-1 consisting of 95 overlapping 15mer peptides. The library was divided into a complete pool, subpools of 10 and 95 single peptides. No precursor frequencies were detected in interferon-gamma (IFN-g)-ELISPOT using the complete and sub-pools. After 7 days of stimulation with subpools, 9 peptides were identified producing high amount of IFN-g in at least 3 donors with different MHC class II alleles (n=6). CD4+ T-cells clones of one peptide were then established by limited dilution cloning. Restriction to DRB1*0401 was identified using LCLs and a tetramer was generated. The peptide-specific T-cell clones showed functional activity against ethanol-inactivated fungus or fungal extracts presented by dendritic cells. To generate Aspergillus-specific TH1 cell lines, we stimulated PBMC with the MHC class II DRB1*0401 restricted peptide. After 7 days of in vitro stimulation (IVS) with interleukin (IL)-2 5U/ml added every other day, tetramer staining was between 0.3 and 11% of CD4+ cells (mean 4.2%, n=5). After 14 days of IVS with 1 restimulation of autologous peptide-pulsed monocytes at a responder: stimulator ratio of 5:1 and IL-7 and IL-15 10ng/ml added after day 7, mean percentages of tetramer staining increased to 37% (range 20-57%, n=4) and absolute cell counts were duplicated. The expansion process was further optimized using IFN-g capture assay and CD154+ MicroBead Kit (Miltenyi). In both assays, PBMC were stimulated for 16 hours, separated by magnetic beads and co-cultured with irradiated autologous PBMC for 14 days using IL-2 5U/ml till day 7 and IL-7 and -15 10ng/ml thereafter. We were unable to expand specific CD4+ cells by IFN-g capture assay in 2 of 3 donors. In contrast, we found that Aspergillus-specific CD4+ cells selected by CD154+ showed comparable tetramer specificity and expansion but higher functional activity in intracellular cytokine assay and IFN-g ELISA than CD4+ cell lines generated from the same donor using the restimulation protocol. The CD4+ cell lines generated by CD154+ expression showed proliferative capacity in CFSE when restimulated with peptides and functional activity in IFN-g ELISA against fungal extracts (n=4). To generate Aspergillus-specific TH1 cell lines recognizing multiple MHC class II epitopes we stimulated PBMC with the previously identified 9 peptides of CRF-1 protein. After 14 days of expansion using CD154+ MicroBead Kit, we measured high IFN-g response towards 4 of 9 peptides (n=3). We are generating T-cell clones and will characterize their HLA-restriction. In summary, we have identified an immunodominant Aspergillus fumigatus protein including 9 MHC class II epitopes. One epitope was characterized specific for an abundant MHC class II allele. CD4+ TH1 cells specific for this epitope can be activated by dendritic cells after uptake of whole fungi or fungal extracts. Furthermore, we have established a GMP-applicable protocol for rapid generation (<14d) of CD4+ T-cell lines specific for Aspergillus fumigatus with low precursor frequency using CD154+ separation. These CD4+ T-cell lines demonstrate functional activity against peptides and fungal extracts that could be prophylactically administered to high risk patients. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Polyclonal expansion of TCR Vbeta 21.3+ CD4+ and CD8+ T cells is a hallmark of Multisystem Inflammatory Syndrome in Children

2021 ◽  
Vol 6 (59) ◽  
pp. eabh1516
Author(s):  
Marion Moreews ◽  
Kenz Le Gouge ◽  
Samira Khaldi-Plassart ◽  
Rémi Pescarmona ◽  
Anne-Laure Mathieu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Expansion ◽  
Healthy Children ◽  
Antigenic Peptides ◽  
T Cell Repertoire ◽  
Cell Repertoire ◽  
Hla Dr ◽  
T Cell Expansion ◽  
Inflammatory Syndrome

Multiple Inflammatory Syndrome in Children (MIS-C) is a delayed and severe complication of SARS-CoV-2 infection that strikes previously healthy children. As MIS-C combines clinical features of Kawasaki disease and Toxic Shock Syndrome (TSS), we aimed to compare the immunological profile of pediatric patients with these different conditions. We analyzed blood cytokine expression, and the T cell repertoire and phenotype in 36 MIS-C cases, which were compared to 16 KD, 58 TSS, and 42 COVID-19 cases. We observed an increase of serum inflammatory cytokines (IL-6, IL-10, IL-18, TNF-α, IFNγ, CD25s, MCP1, IL-1RA) in MIS-C, TSS and KD, contrasting with low expression of HLA-DR in monocytes. We detected a specific expansion of activated T cells expressing the Vβ21.3 T cell receptor β chain variable region in both CD4 and CD8 subsets in 75% of MIS-C patients and not in any patient with TSS, KD, or acute COVID-19; this correlated with the cytokine storm detected. The T cell repertoire returned to baseline within weeks after MIS-C resolution. Vβ21.3+ T cells from MIS-C patients expressed high levels of HLA-DR, CD38 and CX3CR1 but had weak responses to SARS-CoV-2 peptides in vitro. Consistently, the T cell expansion was not associated with specific classical HLA alleles. Thus, our data suggested that MIS-C is characterized by a polyclonal Vβ21.3 T cell expansion not directed against SARS-CoV-2 antigenic peptides, which is not seen in KD, TSS and acute COVID-19.

The lymphoid chemokine CCL21 costimulates naïve T cell expansion and Th1 polarization of non-regulatory CD4+ T cells

2004 ◽  
Vol 231 (1-2) ◽  
pp. 75-84 ◽  
Author(s):  
Kenneth Flanagan ◽  
Dorota Moroziewicz ◽  
Heesun Kwak ◽  
Heidi Hörig ◽  
Howard L. Kaufman
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Cell Expansion ◽  
T Cell Expansion ◽  
Th1 Polarization ◽  
Naïve T Cell ◽  
Naive T Cell

Induction and Break of Immune Tolerance to Human FVIII in a HLA-DRB1*1501 Humanized Hemophilic Mouse Model

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2280-2280
Author(s):  
Katharina Nora Steinitz ◽  
Brigitte Binder ◽  
Christian Lubich ◽  
Rafi Uddin Ahmad ◽  
Markus Weiller ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Mouse Model ◽  
Mhc Class Ii ◽  
Immune Tolerance ◽  
Cd4 T Cells ◽  
Hemophilia A ◽  
Class Ii ◽  
T Cell Epitopes

Abstract Abstract 2280 Development of neutralizing antibodies against FVIII is the major complication in the treatment of patients with hemophilia A. Although several genetic and environmental risk factors have been identified, it remains unclear why some patients develop antibodies while others do not. Understanding the underlying mechanisms that drive the decision of the immune system whether or not to make antibodies against FVIII would help to design novel therapeutics. We used a new humanized hemophilic mouse model that expresses the human MHC-class II molecule HLA-DRB1*1501 on the background of a complete knock out of all murine MHC-class II genes. Initial studies had indicated that only a fraction of these mice developed antibodies when intravenously (i.v.) treated with human FVIII. These findings which resemble the situation in patients with severe hemophilia A, evoked the question if the lack of antibody development in non-responder mice reflects the induction of specific immune tolerance after i.v. application of FVIII or represent non-responsiveness for other reasons. We addressed this question by choosing another application route (subcutaneous, s.c.) and by combining i.v. application with a concomitant activation of the innate immune system applying LPS, a well characterized ligand for toll-like receptor 4, together with FVIII. Both strategies resulted in the development of antibodies in all mice included in the study what suggested that non-responsiveness against i.v. FVIII does not reflect an inability to develop antibodies against FVIII. Next, we asked if i.v. FVIII does induce immune tolerance in non-responder mice. We pretreated mice with i.v. FVIII, selected non-responder mice and challenged them with s.c. FVIII. None of the mice developed antibodies what indicated that i.v. pretreatment had induced immune tolerance in non-responder mice. Currently, we test the hypothesis that immune tolerance after i.v. application is induced and maintained by FVIII-specific regulatory T cells. The differences in responder rates after i.v. and s.c. application of FVIII raised the question if there are differences in FVIII T-cell epitopes involved in the initial activation of FVIII-specific CD4+ T cells. We obtained spleen cells from mice treated with either i.v. or s.c. FVIII and generated CD4+ T-cell hybridoma libraries that were tested for peptide specificities. For this purpose we used a FVIII peptide library containing 15 mers with an offset of 3 amino acids. Our results indicate that the pattern of FVIII-specific T-cell epitopes involved in the activation of FVIII-specific CD4+ T cells after i.v. and s.c. application of FVIII is almost identical and represents a small set of FVIII peptides distributed over the A1, A2, B, A3 and C1 domains. Based on our results we conclude that the new HLA-DRB1*1501 hemophilic mouse model represents an interesting opportunity to uncover the mechanisms that drive the decision of the immune system whether or not to develop antibodies against FVIII. Disclosures: Steinitz: Baxter BioScience: Employment. Binder:Baxter BioScience: Employment. Lubich:Baxter BioScience: Employment. Ahmad:Baxter BioScience: Employment. Weiller:Baxter BioScience: Employment. de la Rosa:Baxter BioScience: Employment. Schwarz:Baxter BioScience: Employment. Scheiflinger:Baxter BioScience: Employment. Reipert:Baxter Innovations GmbH: Employment.

Perforin Is Important For Both CD4+ and CD8+ T Cell-Mediated Graft-Versus-Tumor Effect But Plays Differential Roles In CD4+ and CD8+ T Cell Expansion After Allogeneic Transplantation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3255-3255
Author(s):  
Nicholas Leigh ◽  
Guanglin Bian ◽  
Wei Du ◽  
George L. Chen ◽  
Hong Liu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cell Expansion ◽  
Cd8 T Cell ◽  
Cd4 T Cell ◽  
T Cell Proliferation ◽  
T Cell Expansion ◽  
Time Point

Abstract Graft versus tumor (GVT) effect is the desired and integral outcome for successful allogeneic bone marrow transplantation (allo-BMT) for cancer patients. This effect is dependent on T cell mediated recognition and elimination of residual host tumor cells present after allo-BMT. T cell killing is mediated primarily via three pathways: perforin/granzymes, Fas/FasL, and cytotoxic cytokines. Recent work from our lab has revealed a detrimental role for granzyme B (GzmB) in GVT effect due to its role in activation induced cell death (AICD) of CD8+ T cells. As a result, GzmB-/- CD8+ T cells exhibited higher expansion after allo-BMT and subsequently provided better tumor control. Our current study sought to determine the role of perforin (Prf1) in GVT effect mediated by both CD4+ and CD8+ T cells. Using the MHC-mismatched C57BL/6 (H-2b) to BALB/c (H-2d) allo-BMT model, we first confirmed previous findings that when transplanting CD8+ T cells along with T cell depleted (TCD) BM cells, donor CD8+ T cells require Prf1 to mediate GVT effect against allogeneic A20 lymphoma (Fig 1A, Prf1-/- (n=4) vs WT (n=4), *P<0.05). In addition, our data suggest that Prf1 is also required for CD4+ T cells to effectively mediate GVT effect against A20, as transplant with Prf1-/- CD4+CD25- T cells does not control tumor growth as well as WT controls (Fig 1B). Our previous work showed that GzmB deficiency allows for less AICD and subsequently more CD8+ T cell expansion. New data now show a similar effect for Prf1 in CD8+ T cell accumulation, as Prf1-/- CD8+ T cells outcompete WT CD8+ T cells (CD45.1+) when these two genotypes are mixed in equal numbers and transplanted into tumor bearing BALB/c mice (n=5/time point, *P=0.02 day 9)(Fig 1C). This competitive advantage was due to less AICD in the Prf1-/- CD8+ T cells. However, Prf1 appears to be required for efficient GVT activity, because the higher number of Prf1-/- CD8+ T cells are still less capable than WT counterparts in controlling tumor growth. We next tested the effect of Prf1 in AICD in CD4+CD25- T cells, and again co-transplanted WT CD45.1+ and Prf1-/- CD4+CD25- T cells into tumor bearing mice for a competition assay. Unexpectedly, WT CD4+CD25- T cells accumulate to significantly higher numbers when in direct competition with Prf1-/- CD4+CD25- T cells (n=4/time point, **,P<0.01)(Fig 1D). When we measured apoptotic cells with Annexin V staining, we found that WT CD4+CD25- T cells still had significantly more AICD (Prf1-/- 38.3 ± 4.2% vs. WT 48.1 ± 5.1%, P<0.01 on day 7 post-BMT; Prf1-/- 12.7 ± 1.0% vs. WT 18.1 ± 3.4%, P<0.03 on day 9 post-BMT). This result suggests that while Prf1 has an important role in AICD, it may also play a role in another feature of CD4+ T cell biology. We then explored the hypothesis that may Prf1 promote CD4+ T cell proliferation by evaluating Hoescht staining on day 9 post-BMT. Preliminary results suggest that Prf1 may enhance T cell proliferation, as Prf1-/- CD4+ T cells have less actively dividing cells at this time point. Therefore, Prf1 appears to have a surprising role after allo-BMT in sustaining T cell expansion for CD4+ T cells, but not for CD8+ T cells. Another factor influencing GVT effect may be T cell phenotype. Our previous work with CD8+ T cells suggests that more effector memory (CD62LLOWCD44HIGH) T cells accumulate in the absence of GzmB, and that GzmB-/- CD8+ T cells exhibited higher GVT activity than WT controls. We now found that while Prf1-/- CD4+ T cells also skewed towards the effector memory phenotype (CD62LLOWCD44HIGH), loss of Prf1 still reduced the ability of CD4+ T cells to control tumor growth in this model of allo-BMT. In summary, our results suggest that Prf1 plays an important role in GVT responses mediated not only by CD8+ T cells but also by CD4+ T cells, which were shown in previous literature to mainly utilize Fas ligand and cytokine systems to mediate GVT activity. In addition, Prf1 can cause AICD to both CD4+ and CD8+ T cells after allo-BMT. While Prf1-induced AICD reduces CD8+ T cell expansion, Prf1 appears to play a previously unrecognized role enhancing CD4+ T cell proliferation via an unidentified mechanism. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The Early Kinetics of Cytomegalovirus-Specific CD8+ T-Cell Responses Are Not Affected by Antigen Load or the Absence of Perforin or Gamma Interferon

2008 ◽  
Vol 82 (10) ◽  
pp. 4931-4937 ◽  
Author(s):  
Daniel M. Andrews ◽  
Christopher E. Andoniou ◽  
Peter Fleming ◽  
Mark J. Smyth ◽  
Mariapia A. Degli-Esposti
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Expansion ◽  
T Cell Responses ◽  
Gamma Interferon ◽  
Murine Cytomegalovirus ◽  
Cell Responses ◽  
Ifn Γ ◽  
T Cell Expansion ◽  
Kinetics Of

ABSTRACT Both innate and adaptive immune responses participate in the control of murine cytomegalovirus (mCMV) infection. In some mouse strains, like BALB/c, the control of infection relies on the activities of CD8+ T cells. mCMV-specific CD8+ T-cell responses are unusual in that, even after mCMV has been controlled in the periphery, the numbers of circulating virus-specific CD8+ T cells remain high compared to those observed in other viral infections. To better understand the generation and maintenance of mCMV-specific CD8+ T-cell responses, we evaluated how antigen load and effector molecules, such as perforin (Prf) and gamma interferon (IFN-γ), influence these responses during acute infection in vivo. Viral burden affected the magnitude, but not the early kinetics, of antigen-specific CD8+ T-cell responses. Similarly, the magnitude of virus-specific CD8+ T-cell expansion was affected by Prf and IFN-γ, but contraction of antigen-specific responses occurred normally in both Prf- and IFN-γ-deficient mice. These data indicate that control of mCMV-specific CD8+ T-cell expansion and contraction is more complex than anticipated and, despite the role of Prf or IFN-γ in controlling viral replication, a full program of T-cell expansion and contraction can occur in their absence.

scholarly journals Endogenous human cytomegalovirus gB is presented efficiently by MHC class II molecules to CD4+ CTL

2005 ◽  
Vol 202 (8) ◽  
pp. 1109-1119 ◽  
Author(s):  
Nagendra R. Hegde ◽  
Claire Dunn ◽  
David M. Lewinsohn ◽  
Michael A. Jarvis ◽  
Jay A. Nelson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Glial Cells ◽  
Human Cytomegalovirus ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Host Cells ◽  
Cd4 T Cell

Human cytomegalovirus (HCMV) infects endothelial, epithelial, and glial cells in vivo. These cells can express MHC class II proteins, but are unlikely to play important roles in priming host immunity. Instead, it seems that class II presentation of endogenous HCMV antigens in these cells allows recognition of virus infection. We characterized class II presentation of HCMV glycoprotein B (gB), a membrane protein that accumulates extensively in endosomes during virus assembly. Human CD4+ T cells specific for gB were both highly abundant in blood and cytolytic in vivo. gB-specific CD4+ T cell clones recognized gB that was expressed in glial, endothelial, and epithelial cells, but not exogenous gB that was fed to these cells. Glial cells efficiently presented extremely low levels of endogenous gB—expressed by adenovirus vectors or after HCMV infection—and stimulated CD4+ T cells better than DCs that were incubated with exogenous gB. Presentation of endogenous gB required sorting of gB to endosomal compartments and processing by acidic proteases. Although presentation of cellular proteins that traffic into endosomes is well known, our observations demonstrate for the first time that a viral protein sorted to endosomes is presented exceptionally well, and can promote CD4+ T cell recognition and killing of biologically important host cells.

scholarly journals Genetic Dissection of Primary and Secondary Responses to a Widespread Natural Pathogen of the Gut,Eimeria vermiformis

2000 ◽  
Vol 68 (11) ◽  
pp. 6273-6280 ◽  
Author(s):  
Adrian L. Smith ◽  
Adrian C. Hayday
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Primary Response ◽  
Class I ◽  
Class Ii Mhc ◽  
Ifn Γ ◽  
Αβ T Cells

ABSTRACT Because most pathogens initially challenge the body at epithelial surfaces, it is important to dissect the mechanisms that underlie T-cell responses to infected epithelial cells in vivo. The coccidian parasites of the genus Eimeria are protozoan gut pathogens that elicit a potent, protective immune response in a wide range of host species. CD4+ αβ T cells and gamma interferon (IFN-γ) are centrally implicated in the primary immunoprotective response. To define any additional requirements for the primary response and to develop a comparison between the primary and the secondary response, we have studied Eimeria infections of a broad range of genetically altered mice. We find that a full-strength primary response depends on β2-microglobulin (class I major histocompatibility complex [MHC] and class II MHC and on IFN-γ and interleukin-6 (IL-6) but not on TAP1, perforin, IL-4, Fas ligand, or inducible nitric oxide synthetase. Indeed, MHC class II-deficient and IFN-γ-deficient mice are as susceptible to primary infection as mice deficient in all αβ T cells. Strikingly, the requirements for a highly effective αβ-T-cell-driven memory response are less stringent, requiring neither IFN-γ nor IL-6 nor class I MHC. The class II MHC dependence was also reduced, with adoptively transferable immunity developing in MHC class II−/− mice. Besides the improved depiction of an immune response to a natural gut pathogen, the finding that effective memory can be elicited in the absence of primary effector responses appears to create latitude in the design of vaccine strategies.

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