scholarly journals Primary B Lymphocytes Infected with Kaposi's Sarcoma-Associated Herpesvirus Can Be ExpandedIn Vitroand Are Recognized by LANA-Specific CD4+T Cells

2016 ◽  
Vol 90 (8) ◽  
pp. 3849-3859 ◽  
Author(s):  
Samantha M. Nicol ◽  
Shereen Sabbah ◽  
Kevin F. Brulois ◽  
Jae U. Jung ◽  
Andrew I. Bell ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
B Lymphocytes ◽  
Immune Evasion ◽  
B Lymphocyte ◽  
T Cell Immunity ◽  
Cell Immunity ◽  
Infected Cells

ABSTRACTKaposi's sarcoma-associated herpesvirus (KSHV) has tropism for B lymphocytes, in which it establishes latency, and can also cause lymphoproliferative disorders of these cells manifesting as primary effusion lymphoma (PEL) and multicentric Castleman disease (MCD). T cell immunity is vital for the control of KSHV infection and disease; however, few models of B lymphocyte infection exist to study immune recognition of such cells. Here, we developed a model of B lymphocyte infection with KSHV in which infected tonsillar B lymphocytes were expanded by providing mitogenic stimuli and then challenged with KSHV-specific CD4+T cells. The infected cells expressed viral proteins found in PELs, namely, LANA and viral IRF3 (vIRF3), albeit at lower levels, with similar patterns of gene expression for the major latency, viral interleukin 6 (vIL-6), and vIRF3 transcripts. Despite low-level expression of open reading frame 50 (ORF50), transcripts for the immune evasion genes K3 and K5 were detected, with some downregulation of cell surface-expressed CD86 and ICAM. The vast majority of infected lymphocytes expressed IgM heavy chains with Igλ light chains, recapitulating the features seen in infected cells in MCD. We assessed the ability of the infected lymphocytes to be targeted by a panel of major histocompatibility complex (MHC) class II-matched CD4+T cells and found that LANA-specific T cells restricted to different epitopes recognized these infected cells. Given that at least some KSHV latent antigens are thought to be poor targets for CD8+T cells, we suggest that CD4+T cells are potentially important effectors for thein vivocontrol of KSHV-infected B lymphocytes.IMPORTANCEKSHV establishes a latent reservoir within B lymphocytes, but few models exist to study KSHV-infected B cells other than the transformed PEL cell lines, which have likely accrued mutations during the transformation process. We developed a model of KSHV-infected primary B lymphocytes that recapitulates features seen in PEL and MCD by gene expression and cell phenotype analysis, allowing the study of T cell recognition of these cells. Challenge of KSHV-infected B cells with CD4+T cells specific for LANA, a protein expressed in all KSHV-infected cells and malignanciesin vivo, showed that these effectors could efficiently recognize such targets. Given that the virus expresses immune evasion genes or uses proteins with intrinsic properties, such as LANA, that minimize epitope recognition by CD8+T cells, CD4+T cell immunity to KSHV may be important for maintaining the virus-host balance.

scholarly journals B Cell–dependent T Cell Responses

2002 ◽  
Vol 196 (10) ◽  
pp. 1277-1290 ◽  
Author(s):  
Ryohei F. Tsuji ◽  
Marian Szczepanik ◽  
Ivana Kawikova ◽  
Vipin Paliwal ◽  
Regis A. Campos ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Classical Model ◽  
T Cell Immunity ◽  
Cell Recruitment ◽  
Cell Responses ◽  
Igm Antibodies ◽  
Cell Immunity ◽  
Challenge Antigen

Contact sensitivity (CS) is a classic example of in vivo T cell immunity in which skin sensitization with reactive hapten leads to immunized T cells, which are then recruited locally to mediate antigen-specific inflammation after subsequent skin challenge. We have previously shown that T cell recruitment in CS is triggered by local activation of complement, which generates C5a that triggers C5a receptors most likely on mast cells. Here, we show that B-1 cell–derived antihapten IgM antibodies generated within 1 day (d) of immunization combine with local challenge antigen to activate complement to recruit the T cells. These findings overturn three widely accepted immune response paradigms by showing that (a) specific IgM antibodies are required to initiate CS, which is a classical model of T cell immunity thought exclusively due to T cells, (b) CS priming induces production of specific IgM antibodies within 1 d, although primary antibody responses typically begin by day 4, and (c) B-1 cells produce the 1-d IgM response to CS priming, although these cells generally are thought to be nonresponsive to antigenic stimulation. Coupled with previous evidence, our findings indicate that the elicitation of CS is initiated by rapidly formed IgM antibodies. The IgM and challenge antigen likely form local complexes that activate complement, generating C5a, leading to local vascular activation to recruit the antigen-primed effector T cells that mediate the CS response.

scholarly journals Single-Dose Vaccination with a Hepatotropic Adeno-associated Virus Efficiently Localizes T Cell Immunity in the Liver with the Potential To Confer Rapid Protection against Hepatitis C Virus

2019 ◽  
Vol 93 (19) ◽  
Author(s):  
Zelalem A. Mekonnen ◽  
Branka Grubor-Bauk ◽  
Kieran English ◽  
Preston Leung ◽  
Makutiro G. Masavuli ◽  
...  
Keyword(s):  
T Cells ◽  
Hepatitis C ◽  
T Cell ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Effective Vaccine ◽  
Adeno Associated Virus ◽  
Cell Responses ◽  
Cell Immunity

ABSTRACT Hepatitis C virus (HCV) is a significant contributor to the global disease burden, and development of an effective vaccine is required to eliminate HCV infections worldwide. CD4+ and CD8+ T cell immunity correlates with viral clearance in primary HCV infection, and intrahepatic CD8+ tissue-resident memory T (TRM) cells provide lifelong and rapid protection against hepatotropic pathogens. Consequently, we aimed to develop a vaccine to elicit HCV-specific CD4+ and CD8+ T cells, including CD8+ TRM cells, in the liver, given that HCV primarily infects hepatocytes. To achieve this, we vaccinated wild-type BALB/c mice with a highly immunogenic cytolytic DNA vaccine encoding a model HCV (genotype 3a) nonstructural protein (NS5B) and a mutant perforin (pVAX-NS5B-PRF), as well as a recombinant adeno-associated virus (AAV) encoding NS5B (rAAV-NS5B). A novel fluorescent target array (FTA) was used to map immunodominant CD4+ T helper (TH) cell and cytotoxic CD8+ T cell epitopes of NS5B in vivo, which were subsequently used to design a KdNS5B451-459 tetramer and analyze NS5B-specific T cell responses in vaccinated mice in vivo. The data showed that intradermal prime/boost vaccination with pVAX-NS5B-PRF was effective in eliciting TH and cytotoxic CD8+ T cell responses and intrahepatic CD8+ TRM cells, but a single intravenous dose of hepatotropic rAAV-NS5B was significantly more effective. As a T-cell-based vaccine against HCV should ideally result in localized T cell responses in the liver, this study describes primary observations in the context of HCV vaccination that can be used to achieve this goal. IMPORTANCE There are currently at least 71 million individuals with chronic HCV worldwide and almost two million new infections annually. Although the advent of direct-acting antivirals (DAAs) offers highly effective therapy, considerable remaining challenges argue against reliance on DAAs for HCV elimination, including high drug cost, poorly developed health infrastructure, low screening rates, and significant reinfection rates. Accordingly, development of an effective vaccine is crucial to HCV elimination. An HCV vaccine that elicits T cell immunity in the liver will be highly protective for the following reasons: (i) T cell responses against nonstructural proteins of the virus are associated with clearance of primary infection, and (ii) long-lived liver-resident T cells alone can protect against malaria infection of hepatocytes. Thus, in this study we exploit promising vaccination platforms to highlight strategies that can be used to evoke highly functional and long-lived T cell responses in the liver for protection against HCV.

Antibody Targeting of Activated Dendritic Cells Prevents AGVHD and Preserves T Cell Immunity.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3240-3240
Author(s):  
Hannah Cullup ◽  
John Wilson ◽  
Alison M. Rice ◽  
Anne M. Dickinson ◽  
David J. Munster ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Immunity ◽  
Mouse Serum ◽  
Human Pbmc ◽  
Cell Immunity ◽  
Life Threatening

Abstract AGVHD is a life threatening complication of allogeneic HSCT, initiated by host and donor DC stimulation of donor T lymphocytes. Current AGVHD prophylaxis targets T lymphocytes, compromising anti-viral and therapeutic anti-leukemic responses. The presence of activated blood DC predicts for clinical AGVHD and we predict that a new strategy targeting therapy to activated DC should prevent alloimmune induction of AGVHD but preserve protective T cell immune responses. CD83 is a cell surface molecule expressed by activated DC. Having shown that a rabbit polyclonal antibody to human CD83 (RA83) depletes activated DC and suppresses alloimmune reactions in vitro, we tested the effect of RA83 treatment on T cell immunity in vitro and its ability to prevent human PBMC induced xenogeneic AGVHD in vivo. The effect of RA83 treatment on T cell numbers, proliferation and cytokine secretion in allogeneic MLR was compared with appropriate controls, including Campath-1H. Allogeneic responses in vitro were mirrored in a DC dependent in vivo model of xenogeneic AGVHD, in which 50×106 human PBMC were injected into an irradiated SCID mouse. Human cytokine levels were measured in MLR tissue culture supernatant (TCSN) and mouse serum at the time of sacrifice. Cytotoxic T cell responses to viral antigens (CMV and FMP) were analysed by specific pentamer analysis and Cr51 release assays, prior to and following HLA restricted peptide antigen specific expansion. RA83 was shown to have NK-mediated ADCC capacity. Cellular proliferation in the allogeneic MLR was reduced by both RA83 and Campath-1H treatment (p= 0.004 and 0.01 respectively vs controls) and both antibodies improved mouse survival in the human xenogenic AGVHD model (RA83: 93%, Campath-1H: 100%, p<0.0001). IFN-g was significantly reduced in the TCSN from MLR treated with RA83 (p=0.0391) and in sera taken from RA83 (p=0.0002) and Campath-1H (p=0.0051) treated mice. Serum IL-4 levels were maintained in RA83 and Campath-1H treated mice. The serum levels of IL-5, IL-8 and TNF in mice treated with RA83 were markedly reduced compared to controls (p=0.0256, 0.0025, 0.025, respectively), and the reductions were similar to those seen in Campath-1H treated mice. Similar numbers of T cells were recovered from RA83 treated and control MLR, and both CMV and FMP specific CD8+ T cells were retained. These cells were readily expanded by peptide pulsing and autologous restimulation and had specific cytotoxic activity comparable to control cultures (see figure). In contrast, Campath-1H treatment removed specific anti-viral responses (vs controls: CMV: p<0.00001 and FMP: p=0.0051). Specific antibody to CD83 depletes activated DC in vitro and prevents xenogeneic human DC dependent AGVHD in vivo. This was accompanied by a Th1 to Th2 skewing of the cytokine response. RA83, but not Campath-1H treatment retained normal numbers of T cells and maintained normal cytotoxic responses to common post-transplant viral infections. Depletion of activated DC may be an effective means of AGVHD control, which maintains T cell immunity to life threatening infections and potentially anti-leukaemia responses. RA83 treatment of allo-MLR preserves T cell anti-CMV immunity RA83 treatment of allo-MLR preserves T cell anti-CMV immunity

HTLV-I bZIP Factor Gene, Encoded by the Minus Strand of HTLV-I Provirus, Is Critical for Pathogenesis of HTLV-I Associated Diseases.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1410-1410
Author(s):  
Yorifumi Satou ◽  
Jun-ichirou Yasunaga ◽  
Mika Yoshida ◽  
Koichi Ohshima ◽  
Masao Matsuoka
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
T Cell ◽  
Gene Transcription ◽  
Minus Strand ◽  
Cell Leukemia ◽  
Human T Cell ◽  
Bzip Factor ◽  
Infected Cells

Abstract Human T-cell leukemia virus type I (HTLV-I) causes adult T-cell leukemia (ATL) in about 5% of carriers after a long latent period. HTLV-I is one of complex retrovirus, which encodes accessory genes to control viral replication and proliferation of infected cells. Previous studies reported the pleiotropic actions of tax gene in proliferation of infected cells and leukemogenesis. However, tax gene expression in ATL cells is disrupted by several mechanisms. Our previous study showed that the 5′-LTR of HTLV-I is frequently hypermethylated or deleted in ATL cells, while the 3′-LTR remains unmethylated and intact. These findings suggest the involvement of the 3′-LTR in leukemogenesis. Transcription from the minus strand of HTLV-I has been reported, and the HTLV-I bZIP factor (HBZ) was subsequently found to inhibit Tax-mediated transactivation of viral gene transcription from the 5′-LTR by heterodimerizing with either CREB2, c-Jun or JunB. Based on these previous studies, we hypothesized that HBZ had an important role in ATL cells. We first identified the transcription start site of HBZ gene in the 3′-LTR and found the novel splicing form. The HBZ gene transcription could be detected in all ATL cases and two of three HTLV-I asymptomatic carriers. Suppression of HBZ gene transcription by short hairpin RNA inhibits proliferation of ATL cells. In addition, HBZ gene expression promotes proliferation of a human T-cell line. Transcriptional profiling showed that BTG2, which is known as an antiproliferative molecule, and MX-1, which has an antiviral function, were down regulated. In addition, HBZ up-regulated the transcription of E2F-1 and its target genes. These results suggest that HBZ is associated with the proliferation and survival of HTLV-I infected cells. Furthermore, HBZ mutant analyses suggested that HBZ promotes T-cell proliferation in its RNA form, while HBZ protein suppresses Tax-mediated viral transcription through the 5′-LTR. The studies of microarrays showed that transcriptional changes by HBZ gene could be categorized into two groups: those caused by HBZ RNA and HBZ protein. HBZ protein enhanced the transcription of cellular genes in transfected cells such as GRAP2, an adaptor molecule in the downstream signaling of T cell receptor, which should be important in pathogenesis by HBZ. To analyze the function of HBZ gene in vivo, we generated transgenic (Tg) mice expressing HBZ under the control of the mouse CD4 promoter/enhancer. The percentage of CD4 T cells increased in splenocytes of the Tg mice. In addition, proliferation induced by cross-linking with an immobilized anti-CD3 antibody was augmented in thymocytes of these Tg mice. These data indicate that the HBZ gene promotes proliferation of CD4 T cells in vivo. Interestingly, one of three strains of HBZ mice spontaneously develops dermatitis at about 3–4 months of age. Histological analyses revealed severe dermatitis with massive dermal and epidermal infiltration of lymphocytes. In other strains of transgenic mice, which did not present dermatitis, infiltration of lymphocytes was also observed. In HTLV-I carriers with high provirus loads, infiltration of CD4 T-lymphocytes into the skin has been reported. The spontaneous dermatitis in the HBZ mice resembles to that observed in HTLV-I infected individuals. Taken together, these data suggest that HBZ gene is implicated not only in oncogenesis by HTLV-I, but also in HTLV-I associated diseases.

Blocking VIP Signaling Abrogates Upregulation Of PD1 and Increases Proliferation Of Allo-Reactive T-Cells In a Mixed Lymphocyte Reaction

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1041-1041
Author(s):  
Emily R Summerbell ◽  
Cynthia R. Giver ◽  
Sravanti Rangaraju ◽  
Katarzyna Anna Darlak ◽  
Edmund K. Waller
Keyword(s):  
Flow Cytometry ◽  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
T Cell Immunity ◽  
T Cell Proliferation ◽  
Cell Immunity

Abstract Introduction Vasoactive intestinal peptide (VIP) is a neuropeptide hormone that suppresses Th1 immunity and inhibits antiviral immunity. Decreased Th1 immunity is problematic for allogeneic bone marrow transplant (allo-BMT) patients requiring T-cell immunity against blood cancers (Graft-versus-Tumor) and against secondary infections such as CMV. VIPhyb, a modified VIP peptide, is a VIP receptor antagonist that decreases VIP signaling. VIP-knockout mice and mice treated with VIPhyb after allo-BMT are known to have better antiviral immunity and survival after CMV infection without increasing GvHD (Li et al. PLoS One. 2013 May 27;8(5):e63381) (Li et al. Blood. 2013 Mar 21;121(12):2347-51.), thus making VIPhyb of interest for pharmacological use in humans to improve the efficacy of allo-BMT The effects of VIPhyb on T-cell immunity are not yet fully profiled. This study aimed to analyze the effects of VIPhyb on CD4+ and CD8+ T-cell proliferation and activation in order to better understand the mechanistic implications of VIP inhibition on T-cell adaptive immunity. This study also aimed to show that mixed lymphocyte reactions (MLRs), an in vitro allo-BMT model, could be used to provide rapid and reliable results that are consistent with in vivo data. It was hypothesized that VIPhyb would increase T-cell immunity as profiled by: increased T-cell proliferation, CD69 and PD1 co-upregulation in early T-cell activation, and PD1 downregulation in T-cells after initial activation. Methods Splenocytes from two histoincompatible mice were cultured together at 37°C in a 1:1 ratio in a one-way MLR. BALB/c splenocytes (stimulators) were irradiated at 20Gy, and Pepboy splenocytes (responders) were labeled with CFSE to trace proliferation. VIPhyb was added daily to the cell cultures in doses of 0.1μM, 0.3μM, 1μM, or 3μM. Treatment groups were compared to a PBS control. Proliferation, CD69, and PD1 were assessed by flow cytometry on the BD FACSAria. All results are shown as mean ± SEM (n=3). One-way ANOVA tests with Dunnett post-tests were calculated using Prism software. *p < 0.05; **p < 0.01; ***p < 0.001 Results VIPhyb increased CD4+ and CD8+ T-cell proliferation: 3, 5, and 7 days after initiating a one-way MLR, CFSE expression of Pepboy responder T-cells was assessed using flow cytometry (Figure 1). As the VIPhyb dose increased, the percentage of initial splenocytes that underwent proliferation increased in both CD4+ and CD8+ T-cells. VIPhyb increased early T-cell CD69 expression and abrogated later PD1 upregulation in CD8+ T-cells: 3, 5, and 7 days after initiating a one-way MLR, expression levels of CD69 and PD1 on Pepboy responder T-cells were assessed by flow cytometry. Significant upregulation of CD69 on CD4+ and CD8+ T-cells on day 3 occurred with increasing VIPhyb doses (Figures 2A and 2B). PD1 was co-upregulated with CD69 during early activation, and VIPhyb significantly decreased PD1 expression on CD8+ T-cells on days 5 and 7 (Figures 2C and 2D). Conclusions VIPhyb increased T-cell proliferation; CD8+ T-cells were affected more significantly. VIPhyb increased early co-upregulation of CD69 and PD1 in all T-cells and significantly decreased later CD8+ T-cell PD1 expression, indicating that VIPhyb increases T-cell activation. We hypothesize that the decreased PD1 expression will be critical for understanding the pathways involved in VIP inhibition. Importantly, since it has been shown in vivo that VIPhyb does not increase GvHD, then it can be assumed that the VIPhyb-induced T-cell proliferation and activation will increase GvL and adaptive immunity without increasing alloreactivity. Notably, these results are consistent with published in vivo data, which demonstrates that the MLR can be used as a faster method of analyzing pharmacological compounds than in vivo experiments. Given these results, VIPhyb is still of interest as a potential therapy for allo-BMT patients. Disclosures: No relevant conflicts of interest to declare.

Negative effect of CTLA-4 on induction of T-cell immunity in vivo to B7-1+, but not B7-2+, murine myelogenous leukemia

Blood ◽  
2002 ◽  
Vol 99 (6) ◽  
pp. 2146-2153 ◽  
Author(s):  
James L. LaBelle ◽  
Carrie A. Hanke ◽  
Bruce R. Blazar ◽  
Robert L. Truitt
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
T Cell Immunity ◽  
Myelogenous Leukemia ◽  
Cell Immunity ◽  
B7 Molecules ◽  
Negative Effect

Abstract B7 molecules provide important costimulatory signals to T cells, and B7 genes have been introduced into B7-negative tumor cells to enhance their immunogenicity. However, the role of B7 molecules in inducing tumor immunity is controversial because of conflicting results and reports of differential signaling through the B7 molecules and their ligands CD28 and CTLA-4. In this study, we compared the effect of B7-1 (CD80) and B7-2 (CD86) on the induction of T-cell immunity to C1498, a murine myelogenous leukemia. When cultured with exogenous cytokines in vitro, C1498/B7-1 and C1498/B7-2 induced syngeneic CD8+ T cells to kill parental C1498. In vivo, C1498/B7-1 grew progressively after subcutaneous injection, whereas C1498/B7-2 completely regressed after transient growth in naive mice. Spontaneous rejection of C1498/B7-2 resulted in immunity to challenge doses of C1498 and C1498/B7-1. Antibody-depletion studies in vivo showed that CD8+ T cells rejected C1498/B7-2, whereas only natural killer cells affected the growth of C1498/B7-1. Two approaches were used to determine whether preferential interaction of B7-1 with CTLA-4 contributed to the failure of C1498/B7-1 to activate CD8+ T cells in vivo. First, CTLA-4 specific monoclonal antibody was used to block B7-1–CTLA-4 interaction. Second, CTLA-4 deletional mutant (−/−) bone marrow chimeras were used as tumor hosts. In both systems, there was a significant increase in the rate of rejection of C1498/B7-1 tumors. Resistance to C1498/B7-1 in CTLA-4−/− hosts was mediated by CD8+ T cells. Blocking or deletion of CTLA-4 did not affect the growth of parental C1498, indicating that B7-1 was important for the induction of CD8+ T-cell immunity in the absence of CTLA-4.

scholarly journals A Role of Influenza Virus Exposure History in Determining Pandemic Susceptibility and CD8+T Cell Responses

2016 ◽  
Vol 90 (15) ◽  
pp. 6936-6947 ◽  
Author(s):  
Sergio M. Quiñones-Parra ◽  
E. Bridie Clemens ◽  
Zhongfang Wang ◽  
Hayley A. Croom ◽  
Lukasz Kedzierski ◽  
...  
Keyword(s):  
T Cells ◽  
Influenza Virus ◽  
T Cell ◽  
Immune Evasion ◽  
Memory T Cells ◽  
Influenza Viruses ◽  
T Cell Immunity ◽  
Antigenic Peptides ◽  
Cell Immunity ◽  
Resident Memory T Cells

ABSTRACTNovel influenza viruses often cause differential infection patterns across different age groups, an effect that is defined as heterogeneous demographic susceptibility. This occurred during the A/H2N2 pandemic, when children experienced higher influenza attack rates than adults. Since the recognition of conserved epitopes across influenza subtypes by CD8+cytotoxic T lymphocytes (CTLs) limit influenza disease, we hypothesized that conservation of CTL antigenic peptides (Ag-p) in viruses circulating before the pH2N2-1957 may have resulted in differential CTL immunity. We compared viruses isolated in the years preceding the pandemic (1941 to 1957) to which children and adults were exposed to viruses circulating decades earlier (1918 to 1940), which could infect adults only. Consistent with phylogenetic models, influenza viruses circulating from 1941 to 1957, which infected children, shared with pH2N2 the majority (∼89%) of the CTL peptides within the most immunogenic nucleoprotein, matrix 1, and polymerase basic 1, thus providing evidence for minimal pH2N2 CTL escape in children. Our study, however, identified potential CTL immune evasion from pH2N2 irrespective of age, within HLA-A*03:01+individuals for PB1471-L473V/N476I variants and HLA-B*15:01+population for NP404–414-V408I mutant. Further experiments using the murine model of B-cell-deficient mice showed that multiple influenza infections resulted in superior protection from influenza-induced morbidity, coinciding with accumulation of tissue-resident memory CD8+T cells in the lung. Our study suggests that protection against H2N2-1957 pandemic influenza was most likely linked to the number of influenza virus infections prior to the pandemic challenge rather than differential preexisting CTL immunity. Thus, the regimen of a CTL-based vaccine/vaccine-component may benefit from periodic boosting to achieve fully protective, asymptomatic influenza infection.IMPORTANCEDue to a lack of cross-reactive neutralizing antibodies, children are particularly susceptible to influenza infections caused by novel viral strains. Preexisting T cell immunity directed at conserved viral regions, however, can provide protection against influenza viruses, promote rapid recovery and better clinical outcomes. When we asked whether high susceptibility of children (compared to adults) to the pandemic H2N2 influenza strain was associated with immune evasion from T-cell immunity, we found high conservation within T-cell antigenic regions in pandemic H2N2. However, the number of influenza infections prior to the challenge was linked to protective, asymptomatic infections and establishment of tissue-resident memory T cells. Our study supports development of vaccines that prime and boost T cells to elicit cross-strain protective T cells, especially tissue-resident memory T cells, for lifelong immunity against distinct influenza viruses.

Peptides Derived From Mutated BCR-ABL Elicit T Cell Immunity In CML Patients

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 887-887
Author(s):  
Ann Cai ◽  
Derin Keskin ◽  
Anselmo Alonso ◽  
David DeLuca ◽  
Wandi Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Responses ◽  
T Cell Immunity ◽  
Myelogenous Leukemia ◽  
Class I ◽  
Immunogenic Tumor ◽  
Cell Responses ◽  
Cell Immunity

Abstract Abstract 887 Over 20 BCR-ABL mutations have been identified that result in imatinib resistance and relapse of chronic myelogenous leukemia (CML). CML is highly responsive to immunological manipulations and we therefore hypothesized that mutated BCR-ABL-derived peptides could serve as immunogenic tumor-specific targets. Herein, we present a multi-step strategy for identifying tumor-specific T cell epitopes generated from gene mutation. We first investigated whether peptides derived from 24 frequent BCR-ABL mutations could potentially bind 8 common class I MHC molecules by applying the well-validated prediction servers IEDB and NetMHC to tiled 9- and 10-mers around each mutation. More than 60 peptides were predicted to bind to one or more of the following alleles with IC50<1000: A*0201, A*0301, A*1101, B*0702, B*0801, B*1501, A*0101 or A*2402. From NetMHC, 24 of 84 (29%) were predicted as high (IC50<50), 42 (50%) as intermediate (IC50=50-500), and 18 (21%) as weak binders (1000> IC50>500). From IEDB, 9 of 61 (15%) were predicted as high, 35 (57%) as intermediate and 17 (38%) as weak binders. 24 of 84 mutated peptides (29%) and 24 of 61 mutated peptides (39%) were predicted as binding with at least two-fold higher affinity compared to parental peptides, using NetMHC and IEDB, respectively. These predictions indicated that cells from 7 of 9 imatinib-resistant CML patients had the potential to present at least one mutated BCR-ABL derived peptide by binding autologous HLA alleles (with IC50<1000). CML cells from 3 of the 5 patients had an E255K mutation and expressed HLA-A3, and were predicted to generate two promising candidate peptides: E255K-A247-255 (KLGGGQYGK, IEDB IC50=113; NetMHC IC50=192) and E255K-B255-263 (KVYEGVWKK, IEDB IC50=29; NetMHC IC50=28). Both peptides were predicted to bind HLA-A*0301 at least ten-fold more tightly than parental peptides. Using a competitive MHC binding assay, we confirmed that E255K-A and –B were high binders with IC50 scores of 208nM and 17nM, respectively and that they both had at least ten-fold fold greater affinity than parental peptides. In addition, E255K-B also bound to the other HLA-A3 superfamily members HLA-A*1101, HLA-A*3001, HLA-A*3101, HLA-A*6801 (IC50: 39–603nM). We next successfully generated T cell lines against E255K-B but not E255 K-A from a normal HLA-A3+ donor that demonstrated greater specificity against the mutated peptide (2330±325 SFC/million cells, by IFNγ-ELISPOT) than the parental peptide (1270±42 SFC/million cells). E255K-B is endogenously processed and presented since E255K-B reactive T cells also responded to HLA-A3+ antigen-presenting cells (APCs) that were transfected with a minigene encompassing 227 base pairs surrounding the E255K mutation (1900±85 SFC/million cells). Finally, we assessed the potential for E255K-B to stimulate T cell responses in CML patients. E255K-B elicits T cell immunity in vivo in that we could detect antigen-specific CD8+ T cell reactivity from two HLA-A3+ CML patients bearing the E255K mutation by IFNγ-ELISPOT and by antigen-specific tetramer staining. T cell responses could be abrogated in the presence of class I blocking antibody w6/32. For both patients, reactive T cells were polyfunctional, expressing GM-CSF, IP10 and TNFα in response to APCs pulsed with mutated peptide or expressing the E255K minigene. For Patient 2, E255K reactivity developed only in the setting of donor-derived engraftment following curative allogeneic stem cell transplantation. Further analysis to explore the kinetics of mutated peptide-specific immunity in relationship to burden of mutation-expressing leukemia cells is in progress. Our studies have demonstrated that leukemia-driven genetic alterations can provide immunogenic tumor-specific antigen targets associated with clinical response in vivo. Importantly, even though BCR-ABL mutations generate resistance to imatinib, they also create novel epitopes that can be effectively recognized by cytotoxic CD8+ T cells. Our studies support the development of specific, nontoxic and personalized vaccination strategies for eradication of drug-resistant CML. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Reduced immune-regulatory molecule expression on human colonic memory CD4 T cells in older adults

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Stephanie M. Dillon ◽  
Tezha A. Thompson ◽  
Allison J. Christians ◽  
Martin D. McCarter ◽  
Cara C. Wilson
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Older Persons ◽  
Age Groups ◽  
T Cell Immunity ◽  
Cd4 T Cell ◽  
Cell Immunity ◽  
Memory Cd4 T Cells

Abstract Background The etiology of the low-level chronic inflammatory state associated with aging is likely multifactorial, but a number of animal and human studies have implicated a functional decline of the gastrointestinal immune system as a potential driver. Gut tissue-resident memory T cells play critical roles in mediating protective immunity and in maintaining gut homeostasis, yet few studies have investigated the effect of aging on human gut T cell immunity. To determine if aging impacted CD4 T cell immunity in the human large intestine, we utilized multi-color flow cytometry to measure colonic lamina propria (LP) CD4 T cell frequencies and immune-modulatory marker expression in younger (mean ± SEM: 38 ± 1.5 yrs) and older (77 ± 1.6 yrs) adults. To determine cellular specificity, we evaluated colon LP CD8 T cell frequency and phenotype in the same donors. To probe tissue specificity, we evaluated the same panel of markers in peripheral blood (PB) CD4 T cells in a separate cohort of similarly aged persons. Results Frequencies of colonic CD4 T cells as a fraction of total LP mononuclear cells were higher in older persons whereas absolute numbers of colonic LP CD4 T cells per gram of tissue were similar in both age groups. LP CD4 T cells from older versus younger persons exhibited reduced CTLA-4, PD-1 and Ki67 expression. Levels of Bcl-2, CD57, CD25 and percentages of activated CD38+HLA-DR+ CD4 T cells were similar in both age groups. In memory PB CD4 T cells, older age was only associated with increased CD57 expression. Significant age effects for LP CD8 T cells were only observed for CTLA-4 expression, with lower levels of expression observed on cells from older adults. Conclusions Greater age was associated with reduced expression of the co-inhibitory receptors CTLA-4 and PD-1 on LP CD4 T cells. Colonic LP CD8 T cells from older persons also displayed reduced CTLA-4 expression. These age-associated profiles were not observed in older PB memory CD4 T cells. The decline in co-inhibitory receptor expression on colonic LP T cells may contribute to local and systemic inflammation via a reduced ability to limit ongoing T cell responses to enteric microbial challenge.

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

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

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

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