scholarly journals T cell immune discriminants of HIV reservoir size in a pediatric cohort of perinatally infected individuals

2021 ◽  
Vol 17 (4) ◽  
pp. e1009533
Author(s):  
Stefano Rinaldi ◽  
Lesley de Armas ◽  
Sara Dominguez-Rodríguez ◽  
Suresh Pallikkuth ◽  
Vinh Dinh ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Cd4 T Cells ◽  
Viral Reservoir ◽  
Molecular Profile ◽  
Viral Control ◽  
Hiv Reservoir ◽  
Hiv Dna

The size of the latent HIV reservoir is associated with the timing of therapeutic interventions and overall health of the immune system. Here, we demonstrate that T cell phenotypic signatures associate with viral reservoir size in a cohort of HIV vertically infected children and young adults under durable viral control, and who initiated anti-retroviral therapy (ART) <2 years old. Flow cytometry was used to measure expression of immune activation (IA), immune checkpoint (ICP) markers, and intracellular cytokine production after stimulation with GAG peptides in CD4 and CD8 T cells from cross-sectional peripheral blood samples. We also evaluated the expression of 96 genes in sort-purified total CD4 and CD8 T cells along with HIV-specific CD4 and CD8 T cells using a multiplexed RT-PCR approach. As a measure of HIV reservoir, total HIV-DNA quantification by real-time PCR was performed. Poisson regression modeling for predicting reservoir size using phenotypic markers revealed a signature that featured frequencies of PD-1+CD4 T cells, TIGIT+CD4 T cells and HIV-specific (CD40L+) CD4 T cells as important predictors and it also shows that time of ART initiation strongly affects their association with HIV-DNA. Further, gene expression analysis showed that the frequencies of PD-1+CD4 T cells associated with a CD4 T cell molecular profile skewed toward an exhausted Th1 profile. Our data provide a link between immune checkpoint molecules and HIV persistence in a pediatric cohort as has been demonstrated in adults. Frequencies of PD-1+ and TIGIT+CD4 T cells along with the frequency of HIV-specific CD4 T cells could be associated with the mechanism of viral persistence and may provide insight into potential targets for therapeutic intervention.

scholarly journals Restriction of HIV-1 replication in macrophages and CD4+ T cells from HIV controllers

Blood ◽  
2011 ◽  
Vol 118 (4) ◽  
pp. 955-964 ◽  
Author(s):  
Asier Sáez-Cirión ◽  
Chiraz Hamimi ◽  
Anna Bergamaschi ◽  
Annie David ◽  
Pierre Versmisse ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Ex Vivo ◽  
Cd4 T Cell ◽  
Viral Reservoir ◽  
Cell Resistance ◽  
Viral Control ◽  
Hiv Controllers ◽  
Hiv 1

Abstract How HIV controllers (HICs) maintain undetectable viremia without therapy is unknown. The strong CD8+ T-cell HIV suppressive capacity found in many, but not all, HICs may contribute to long-lasting viral control. However, other earlier defense mechanisms may be involved. Here, we examined intrinsic HIC cell resistance to HIV-1 infection. After in vitro challenge, monocyte-derived macrophages and anti–CD3-activated CD4+ T cells from HICs showed low HIV-1 susceptibility. CD4 T-cell resistance was independent of HIV-1 coreceptors and affected also SIVmac infection. CD4+ T cells from HICs expressed ex vivo higher levels of p21Waf1/Cip1, which has been involved in the control of HIV-1 replication, than cells from control subjects. However, HIV restriction in anti–CD3-activated CD4+ T cells and macrophages was not associated with p21 expression. Restriction inhibited accumulation of reverse transcripts, leading to reduction of HIV-1 integrated proviruses. The block could be overcome by high viral inocula, suggesting the action of a saturable mechanism. Importantly, cell-associated HIV-1 DNA load was extremely low in HICs and correlated with CD4+ T-cell permissiveness to infection. These results point to a contribution of intrinsic cell resistance to the control of infection and the containment of viral reservoir in HICs.

scholarly journals 643 Vasoactive intestinal peptide as a novel immune checkpoint molecule in activated T cells

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A672-A672
Author(s):  
Sruthi Ravindranathan ◽  
Tenzin Passang Fnu ◽  
Edmund Waller
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vasoactive Intestinal Peptide ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Checkpoint Inhibitors ◽  
Activated T Cells

BackgroundOnly a fraction of cancer patients responds to current antibody-based immune checkpoint inhibitors.1 Our lab has identified vasoactive intestinal peptide-receptor (VIP-R) signaling as a targetable immune checkpoint pathway in cancer. VIP is a small neuropeptide with known immunosuppressive effects on T cells, in particular, CD4+ T cells.2–5 However, little is known about VIP-R signaling in CD8+ T cells. To define mechanisms by which VIP limits T cell activation and function, we studied the regulation of VIP and VIP receptors (VIP-R) in T cells following their activation in vitro and in mouse models of cancer.MethodsT cells from healthy human donors and murine splenocytes were activated using anti-CD3 coated plates. Western blots measured intracellular pre-pro-VIP, along with its cognate receptors; VPAC1 and VPAC2. Purified cultures of CD4+ and CD8+ T cells were used to interrogate the protein expression on specific T cell subsets. Activation and chemokine receptor expression was assessed by flow cytometry to evaluate T cell response to VIP-R antagonists in vitro and in tumor-bearing mice engrafted with pancreatic cancer cell lines.ResultsBoth murine and human T cells upregulate pre-pro-VIP following TCR stimulation with similar kinetics of VIP receptors between species. VIP expression is upregulated in vivo following treatment of tumor-bearing mice with anti-PD1 MoAb. VIP expression is temporally correlated with the upregulation of other co-inhibitory molecules. VPAC1 expression modestly increased in activated T cells while VPAC2 expression decreased. A non-canonical high molecular weight (HMW) form of VPAC2-related protein robustly and transiently increase in activated T cells. Expression of HMW form of VPAC2 is only detected in activated CD4+ T cells. Of note, activated CD4+ but not CD8+ T cells upregulate pre-pro-VIP. Pharmacological inhibition of VIP-R signaling significantly increased CD69+, OX40+, Lag3+, and PD1+ expression in CD4+ subsets compared to activated T cells without VIP-R antagonists (p < 0.05). In contrast, CD8+ T cells upregulate VPAC1 but not VPAC2 receptor following activation. VIP-R antagonist treatment of activated CD8+ T cells significantly decreased CXCR4+ expression (p < 0.05). CXCR3 and CXCR5 expression were not affected by VIP-R antagonist treatment.ConclusionsVIP-R signaling is a novel immune autocrine and paracrine checkpoint pathway in activated CD4+ T cells. Activated CD4+ and CD8+ T cells demonstrate different kinetics of VPAC1 and VPAC2 expression, suggesting different immune-regulatory responses to VIP-R antagonists. Understanding VIP-R signaling induced during T cell activation can lead to specific drugs that target VIP-R pathways to enhance cancer immunotherapy.AcknowledgementsWe thank healthy volunteers for blood samples. The authors also thank the shared resources at Emory University, namely, Emory Flow Cytometry Core (EFCC) and Integrated Cellular Imaging Core (ICI) and Yerkes Nonhuman Primate Genomics Core that provided services or instruments at subsidized cost to conduct some of the reported experiments. This work was supported in part by Katz Foundation funding, Georgia Research Alliance, and Emory School of Medicine Dean's Imagine, Innovate and Impact (I3) venture award to Edmund K. Waller.ReferencesDarvin P, Toor SM, Sasidharan Nair V, Elkord E. Immune checkpoint inhibitors: recent progress and potential biomarkers. Experimental and Molecular Medicine 2018.Wang HY, Jiang XM, Ganea D. The Neuropeptides VIP and PACAP Inhibit IL-2 Transcription by Decreasing c-Jun and Increasing JunB Expression in T Cells. J Neuroimmunol 2000;104(1):68–78.Delgado M. Vasoactive intestinal peptide generates CD4+CD25+ regulatory T Cells in Vivo. J Leukoc Biol 2005.Anderson P, Gonzalez-Rey E. Vasoactive intestinal peptide induces cell cycle arrest and regulatory functions in human T cells at multiple levels. Mol Cell Biol 2010.Delgado M, Ganea D. Vasoactive intestinal peptide: a neuropeptide with pleiotropic immune functions. Amino Acids. NIH Public Access July 2013, 25–39.Ethics ApprovalDe-identified blood samples from consented healthy volunteers (IRB 00046063) were obtained with approval from Institutional Review Boards.

T Cells from Chronic Lymphocytic Leukemia (CLL) Patients Display Dysregulated Expression of Immune Checkpoint Molecules and Activation Markers Mainly Restricted to CD4+ Cells and Correlated with Disease Activity

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4132-4132
Author(s):  
Marzia Palma ◽  
Giusy Gentilcore ◽  
Fariba Mozaffari ◽  
Kia Heimersson ◽  
Barbro Näsman-Glaser ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Immune Checkpoint ◽  
Cd4 T Cells ◽  
Research Funding ◽  
Immune Checkpoints ◽  
Activated T Cells ◽  
Activation Markers ◽  
Cd8 Cells

Abstract Background CLL patients (pts) have impaired humoral and cellular immune functions, which is largely due to profound defects of T-cells. Regulation and activation of T lymphocytes depend not only on T cell receptor signaling but also on co-signaling receptors delivering either inhibitory or stimulatory signals, known as immune checkpoints. CTLA-4 (cytotoxic T lymphocyte-associated antigen-4) is transiently expressed on activated T cells, binding the same ligands as CD28, inhibiting T-cell activation. Similarly, programmed cell death protein 1 (PD-1) is expressed on activated CD4+ and CD8+ T cells inhibiting T-cell functions upon binding to the ligands B7-H1 (PD-L1, CD274) and B7-DC (PD-L2, CD273). CD137 is an inducible costimulatory receptor expressed by activated T cells. Dysregulated expression of immune checkpoint receptors on T cells of CLL pts may have an impact on T-cell responsiveness and might be a mechanism for the immune deficiency in the disease. Aim To evaluate the expression of the immune checkpoint molecules CTLA-4, PD-1 and CD137 as well as of the cell proliferation marker Ki67, the activation marker CD69 and of CD103, a marker expressed on regulatory T cells, in T cells from CLL pts in different disease phases. Methods Peripheral blood samples were obtained from 69 CLL pts and 13 healthy control donors (HD). Pts were sub-grouped according to disease phase: indolent vs progressive (i.e. fulfilling criteria for active disease). The expression of CTLA-4, PD-1, PD-L1, CD69, CD103, CD137 and Ki-67 was assessed by flow-cytometry on CD4+ and CD8+ T cells. We also analysed the change in expression of these markers on T cells after 72 hours of PHA stimulation. Results CLL pts (n=17) had a significanty higher percentage of proliferating (Ki67+) CD3+ cells compared to HD (n=7) (median 3.7% in progressive vs 1.7% in indolent CLL vs 0.9% in HD, p=0.004 and p=0.04, respectively) (Fig.1). Progressive CLL pts had a significantly higher percentage Ki67+ CD4+ compared to indolent pts as well as HD (p=0.007 and p=0.001, respectively). Both indolent and progressive pts had higher percentage of Ki67+ CD8+ T cells compared to HD (p=0.01 and p=0.03, respectively). The percentage of CTLA-4+ CD4+ and CTLA-4+ CD8+ cells was low in CLL pts as well as in HD. However, the percentage of PD-1+ CD4+ T cells was significantly higher in progressive (n=32) as compared to indolent (n=35) CLL pts (median 40.3% vs 23.3%, p<0.0001) and HD (n=13) (median 21.5%, p<0.0001) (Fig.2) and correlated positively to the white blood cell counts (WBC) at the time of testing (r=0.29, p=0.03), while no difference was found with regard to the percentage of PD-1+ CD8+ T cells. No difference was observed between CLL pts and HD regarding the expression of PD-L1 on T cells. Both the percentage of CD69+ CD4+ and CD137+ CD4+ T cells were significantly higher in progressive as compared to indolent disease and correlated positively to WBC while no difference was found seen in CD8+ T cells. The percentage of CD103+ T cells was significantly lower in progressive compared to and HD within both the CD4+ (p=0.02) and the CD8+ subpopulations (p=0.02). After 72-hrs of PHA stimulation, PD-1 and CTLA-4 expression increased in CD4+ and CD8+ cells to a similar extent in CLL pts and HD, while PD-L1 increased in HD but not in progressive CLL pts (p=0.03 and p=0.007 for CD4+ and CD8+ cells, respectively). CD69 expression increased to a similar extent in CLL pts and HD, while CD137 expression increased more in T cells from progressive pts compared to HD (p=0.03 and 0.01 for the CD4+ and CD8+ cells, respectively). No increase in CD103 on CD8+ T-cells was observed in CLL pts compared to HD (p=0.04 and p=0.01 for the indolent and progressive pts, respectively). Conclusions Progressive CLL pts have more proliferating (Ki67+) T cells in both the CD4+ and CD8+ compartments compared to HD. CD4+ T-cells in progressive CLL pts display an activated phenotype (CD69+) and express the immune co-stimulatory molecule CD137 at a significantly higher level compared to indolent pts and HD. Nevertheless, the expression of the inhibitory immune checkpoint molecule PD-1 is so high that it is reasonable to assume that these cells are heavily impaired in their immune functions. The differences observed in the expression of immune checkpoints and activation markers between CLL pts in different phases of the disease suggest that major changes occur in the CD4+ T-cell compartment during disease progression. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Hansson: Jansse Cilag: Research Funding. Österborg:Janssen, Pharmacyclics, Gilead: Consultancy, Research Funding; Novartis: Research Funding.

scholarly journals In Virologically Suppressed HIV+ Patients, High CD4/CD8 Ratio and Length of Treatment Independently Correlate to the Intracellular Content of Proviral HIV-DNA in Different Types of CD4+ T Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3704-3704
Author(s):  
Andrea Cossarizza ◽  
Sara De Biasi ◽  
Elena Bianchini ◽  
Margherita Digaetano ◽  
Simone Pecorini ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Telomere Length ◽  
Cd4 T Cells ◽  
Digital Pcr ◽  
Cd4 T Cell ◽  
Hiv Reservoir ◽  
Hiv Dna ◽  
Length Of Treatment ◽  
Lymphocyte Populations

Abstract Introduction:Potent antiretroviral drugs block the progression of HIV infection and inhibit virus integration into the host DNA. Response to therapy is typically monitored by counting CD4+ T cells and measuring plasma viral load, which becomes undetectable in most patients. However, at present HIV cannot be eradicated and persists in the host. Robust data are needed to understand the importance and clinical meaning of the residual activity of the virus, and it is crucial to investigate the role of intracellular HIV reservoirs in patients with undetectable viremia. Since HIV establishes latent infection at different degrees within central memory (CM), effector memory (EM) or naïve (TN) CD4+ T cells, measuring the content of HIV-DNA in different lymphocyte populations is a novel approach to follow the infection. Similarly, the residual capacity of the host to reconstitute the immune system can be accurately monitored by measuring: i) the amount of cells expressing signal-joint (sj) T cell receptor (TCR) rearrangement excision circles (sjTREC), that are a marker of homeostatic proliferation, and ii) telomere length, for evaluating cell senescence. Thus, using flow cytometry and cell sorting along with a molecular biology approach based on droplet digital PCR (ddPCR), we have quantified proviral HIV DNA, the amount of sjTREC+ cells and telomere length in different subsets of CD4+ T cells, such as TN, CM and EM. Methods:According to the Declaration of Helsinki, after informed consent and approval by the local Ethical Committee, we enrolled 32 HIV+ patients (mean age 49.0±7.2 years, 11 females) successfully treated for >2 years, with a CD4+ T cell count >500 cells/uL and plasma viremia undetectable from at least one year. After staining with fluorochrome-labeled mAbs, TN, CM and EM CD4+ T cells were sorted with a S3e sorter (Bio-Rad, CA, USA) equipped with a specifically designed biosafety containment hood (Biobubble, UK). Cell purity was always >95%. Proviral HIV-DNA and sjTREC were quantified in each lymphocyte subset with QX200 droplet digital PCR (Bio-Rad); telomere length, expressed as relative T/S (the ratio between telomere length and single gene copy, related to CD178, i.e., Fas Ligand) was quantified with CFX9600 Real time PCR (Bio-Rad). Viro-immunological parameters such as CD4+ and CD8+ T cell counts and percentages, and viral load were collected for each withdrawal together with the clinical characteristics of patients. Results:Considering all patients, HIV proviral DNA, measured as LTR copies/1,000 cells, was significantly lower in TN cells (mean±SEM: 0.77±0.23) compared to CM (2.42±0.38) or to EM (2.34±0.33), with p<0.0001 in both cases. Conversely, TN cells contained a higher number of sjTREC copies/1,000 cells (11.62±1.54) compared to CM (0.99±0.23) or to EM (1.26±0.44); p<0.0001 in both comparisons. No appreciable changes were observed in T/S ratio among CD4+ subsets. The stratification of patients revealed that HIV content was significantly higher in TN and CM T cells of patients with shorter time of treatment. Similarly, stratifying for CD4/CD8 ratio revealed that those with lower ratio had more intracellular HIV. A similar trend was observed also in EM cells, even if it was not statistically significant. The CD4+ T cell count pre-therapy or CD4+ T cell nadir did not influence the HIV reservoir. Conclusions: The importance of recovering a good CD4/CD8 ratio after successful antiretroviral therapy is further underlined by the fact that different amounts of virus were present and well measurable in different CD4+ T cell populations from patients with high or low ratio. The length of treatment was also significantly correlated to a better virological outcome. It is to note that in our patients homeostatic proliferation or cell senescence likely did not affect HIV reservoir. Linking highly purified cell sorting to a molecular biology approach based on ddPCR is crucial to understand what happens to the HIV reservoir when plasma viremia is suppressed. The measure of HIV DNA in selected lymphocyte populations not only will lead to a better comprehension of the features of HIV reservoir and its monitoring, but could also be useful for the development of eradication strategies. 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.

scholarly journals 739 Intratumor childhood vaccine-specific CD4+ T cell recall helps antitumor CD8 T cells

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A770-A770
Author(s):  
Michael Brown ◽  
Zachary McKay ◽  
Yuanfan Yang ◽  
Darell Bigner ◽  
Smita Nair ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Viral Replication ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Antitumor Efficacy ◽  
Polio Vaccine ◽  
Recall Antigen ◽  
Childhood Vaccine

BackgroundPVSRIPO, a recombinant poliovirus derived from the live-attenuated Sabin oral polio vaccine strain, is being tested in multi-institutional phase II clinical trials for recurrent glioblastoma (NCT04479241) and unresectable, PD-1 refractory melanoma (NCT04577807) in combination with PD1 blockade. PVSRIPO capsid is identical to the Sabin vaccine strain and >99% identical to the inactivated Polio vaccine (IPOL, Salk), against which public health mandated childhood vaccination is near universal. In non-vaccinated mice, PVSRIPO mediates antitumor efficacy in a replication-dependent manner via engaging innate inflammation and antitumor T cells. Accordingly, it is anticipated that pre-existing immunity to PVSRIPO impedes antitumor therapy. However, recent evidence indicates that immunological 'recall', or reactivation of memory T cells, may mediate anti-tumor effects.MethodsThe impact of prior polio vs control (KLH) vaccination on intratumor viral replication, tumor inflammation, and overall tumor growth after intratumor PVSRIPO therapy was assessed in murine tumor models. The role of polio capsid and tetanus recall antigens in mediating intratumor inflammation and antitumor efficacy was similarly studied in mice non-permissive to PVSRIPO infection. To mechanistically define antitumor effects of polio recall, B cell and CD8 T cell knockout mice were used, in addition to adoptive transfer of CD4+ T cells from vaccinated mice. Intratumor polio or tetanus recall antigen therapy was performed after OT-I transfer (OVA-specific T cells) in the B16-OVA melanoma model to gauge antitumor T cell activity. Lastly, the inflammatory effects of polio and tetanus antigens was tested in human peripheral blood mononuclear cells (PBMCs).ResultsDespite curtailing intratumor viral replication, prior polio vaccination in mice potentiated subsequent antitumor efficacy of PVSRIPO. Intratumor recall responses induced by polio and tetanus antigens also delayed tumor growth. Recall antigen therapy was associated with marked intratumor influx of eosinophils, conventional CD4+ T cells, and increased expression of IFN-g, TNF, and Granzyme B in tumor infiltrating T cells. The antitumor efficacy of polio recall antigen was mediated by CD4+ T cells, partially depended upon CD8+ T cells, and was impaired by B cells. Both polio and tetanus recall antigen therapy bolstered the antitumor function of tumor-specific OT-I CD8+ T cells. Polio and tetanus antigens induced CXCL10 and type I/II/III IFNs in PBMCs in vitro.ConclusionsChildhood vaccine-specific CD4+ T cells hold cancer immunotherapy potential. In the context of PVSRIPO therapy, antitumor and inflammatory effects of polio vaccine-specific CD4+ T cell recall supersedes inhibitory effects of attenuated intratumor viral replication, and represents a novel mechanism of action.Ethics ApprovalThe animal work described in this study was approved by the Duke University IACUC.

scholarly journals 754 TIGIT-PVR is a key immune checkpoint and therapeutic target in HPV-positive head and neck squamous cell carcinomas

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A788-A788
Author(s):  
Xiuning Le ◽  
Minghao Dang ◽  
Venkatesh Hegde ◽  
Bo Jiang ◽  
Ravaen Slay ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Murine Model ◽  
Immune Checkpoint ◽  
Therapeutic Target ◽  
Therapeutic Efficacy ◽  
Cd8 T Cell ◽  
Immune Checkpoints ◽  
Rna Seq

BackgroundHuman papillomavirus (HPV)-positive head and neck squamous cell carcinoma (HPV+ HNSCC) is a disease that has moderate response to anti-PD-1/L1 immune checkpoint blockade, with the response rates less than 20% and median progression-free survival less than 3 months. A greater understanding of tumor intrinsic and extrinsic factors that restrict anti-tumor immunity in the tumor immune microenvironment (TIME) is needed to identify other immune checkpoints to enhance therapeutic efficacy.MethodsTwo cohorts (TCGA n=72 and a separate cohort n=84) of surgically resected, treatment-naïve HPV+ HNSCC with RNA-seq were analyzed to understand the immune features. In addition, single-cell RNA-seq and TCR-seq were performed on 18 cases to further delineate the immune molecules' interactions. An immune-competent murine HPV+ HNSCC model was used to preliminarily evaluate the therapeutic efficacy.ResultsIn two bulk-sequenced HPV+ HNSCC cohorts, TIGIT ligands PVR and NECTIN2 were found to associate with an epithelial-to-mesenchymal gene expression signature, suppression of IFNα and IFNγ signaling, a stromal-enriched or immune-excluded TIME, and poor survival. Single-cell RNA-seq of over 72,000 cells of HPV+ HNSCC revealed that the PVR/NECTIN ligand TIGIT was highly prevalent in T-cells (34%), significantly higher than PD1- (20%, p<0.01). There is an enrichment of cell-cell interactions mediated by TIGIT-PVR/NECTIN2 in the TIME of HPV+HNSCC versus normal tonsil. TIGIT was the most differentially upregulated immune checkpoint on clonally expanded CD8+T-cells and was abundant on antigen-experienced, tissue-resident memory CD8+T-cell and T-regulatory subsets. TIGIT ligands PVR, NECTIN1, and NECTIN2 were abundant on mature regulatory dendritic cells (DCs), immunosuppressive plasmacytoid (p)DCs, and macrophages, respectively. TIGIT and PD-1 co-blockade in the mEER syngeneic murine model significantly reduced tumor growth, improved survival, restored effector function of HPV16E7-specific CD8+T cells, natural killer cells, and DCs, and conferred tumor re-challenge protection.ConclusionsTIGIT-PVR/NECTIN receptors/ligands are more abundant than PD-1/L1 in the TIME of HPV+ HNSCC. Co-blockade of TIGIT and PD-1 immune checkpoints enhanced anti-tumor efficacy in a CD8+ T-cell-dependent manner and conferred long-term immune protection in a murine model. Our study nominates TIGIT as a therapeutic target for HPV+ HNSCC.

scholarly journals Donor Lymphocyte Infusions Correct Deficiency of Naive T Cells and Improve T-Cell Competence after Allogeneic Haematopoietic Stem Cell Transplantation with Lymphocyte Depletion

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2233-2233
Author(s):  
Monera Al Rukhayes ◽  
Victoria T Potter ◽  
Pilar Perez-Abellan ◽  
Jesus Feliu ◽  
Lajos Floro ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Healthy Volunteers ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Haematopoietic Stem Cell ◽  
Naive T Cells ◽  
Lymphocyte Depletion ◽  
Naïve T Cells ◽  
Repertoire Diversity

Abstract Lymphocyte-depletion effectively reduces risk of graft versus host disease (GvHD) after allogeneic haematopoietic stem cell transplantation (allo-HSCT), but risk of infections and malignant disease relapse remains high. We have previously reported that pre-emptive donor lymphocyte infusions (pDLI) given to patients after allo-HSCT for myeloid malignancies to reverse falling donor T-cell chimerism improve overall and relapse-free survival. GvHD rates after pDLI were not high and grade rarely severe. To investigate the basis for better outcome after pDLI, we have assessed recovery of lymphocyte subsets, T-cell receptor (TCR) diversity and T-cell functional competence after allo-HSCT with fludarabine and busulphan in cohorts of 59 patients (median age 59) given alemtuzumab for lymphocyte-depletion and 34 patients (median age 58) given anti-thymocyte globulin (ATG). Lymphocytes were significantly less depleted with ATG compared to alemtuzumab (Day 30: Median 3.9 x 108/liter versus 2.3x108/liter, P=0.03) but numbers for both ATG and alemtuzumab remained significantly below the normal range (median 2.34x109/liter for 11 aged-matched healthy volunteers) for at least one year (Day 360 P<0.005: Median 8.35 x 108/liter after ATG; median 1.04 x 109/liter after alemtuzumab). Lymphocyte subset composition was similar after ATG or alemtuzumab, and abnormal. Notable, the T-cell population comprised only memory and effector T cells early after HSCT. These cells expressed significantly higher levels of Ki67 than T cells from healthy volunteers (Day 30 P<0.005: Median CD4 T cells 41.3% Ki67+ after ATG, 66% after alemtuzumab compared to 2.51% for healthy volunteers; median CD8 T cells 18.5% Ki67+ after ATG, 50.8% after alemtuzumab compared to 2.58% for healthy volunteers). This marker is indicative of homeostatic proliferation likely driven by increased levels of IL7 and IL15 detected in the serum of patients early after HSCT compared to healthy volunteers (Day 30 P=0.066 and P<0.005 respectively). Higher frequency of T cells expressing the proliferation marker in patients treated with alemtuzumab was associated with high frequencies of T cells expressing the PD1 marker, indicative of exhaustion (Day 30 P<0.005: Median CD4 T cells 84.0% PD1+ after alemtuzumab compared to 6.35% for healthy volunteers; median CD8 T cells 49.1% PD1+ after alemtuzumab compared to 12.3% for healthy volunteers). Expression of PD1 by T cells was near normal in patients treated with ATG. Naïve T cells were typically absent for at least six months after HSCT following lymphocyte depletion with ATG or alemtuzumab, and any subsequent recovery was poor. In contrast, the naïve T-cell population increased rapidly in patients after pDLI (n=18). Six of these patients received pDLI early after HSCT (at 3-5 months) and naïve T-cell recovery was significantly enhanced at six months compared to patients that did not receive pDLI (Day 180 P<0.005: Median 19.25% naïve CD4 T cells compared to 1.36%; median 23.5% naïve CD8 T cells compared to 3.48%). Naïve T cells are the main source of repertoire diversity and responsible for responses to antigens not previously encountered. Analysis of the TCR β chain repertoire of five patients by deep sequencing revealed that pDLI boosts repertoire diversity. For example, unique TCR β chain sequences increased 31-fold in 150 days after pDLI compared to a 2-fold increase during a similar period for another patient that did not receive DLI. Furthermore, instances of emergence of public clonotypes specific for CMV or EBV that were not detected before DLI were seen in virus-positive patients whose donors were virus-negative. Emergence and rapid expansion of donor-derived clonotypes to frequencies up to 6.75% suggests that naïve T cells present in the DLI had been primed upon encounter with virus in the patient. In vitro stimulation with overlapping 15-mer peptide libraries for CMV antigens and EBV antigens followed by assessment of activation marker expression and interferon-γ, MIP-1β, and TNF-α production showed that virus-specific T-cell responses increased in magnitude and poly-functionality after DLI. These findings show that DLI replenishes naïve T cells and restores ability to respond to viral antigens previously unseen. By inference, this may extend to leukaemia antigens and underlie the reduced rate of malignant disease relapse seen in patients given pDLI. Disclosures No relevant conflicts of interest to declare.

scholarly journals IL-15 regulates susceptibility of CD4+ T cells to HIV infection

2018 ◽  
Vol 115 (41) ◽  
pp. E9659-E9667 ◽  
Author(s):  
Lara Manganaro ◽  
Patrick Hong ◽  
Matthew M. Hernandez ◽  
Dionne Argyle ◽  
Lubbertus C. F. Mulder ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Hiv Infection ◽  
Memory Cell ◽  
Viral Reservoir ◽  
Cell Infection ◽  
Hiv Reservoir ◽  
Sam Domain ◽  
Reservoir Stimulation ◽  
Immune Profiling

HIV integrates into the host genome to create a persistent viral reservoir. Stimulation of CD4+ memory T lymphocytes with common γc-chain cytokines renders these cells more susceptible to HIV infection, making them a key component of the reservoir itself. IL-15 is up-regulated during primary HIV infection, a time when the HIV reservoir established. Therefore, we investigated the molecular and cellular impact of IL-15 on CD4+ T-cell infection. We found that IL-15 stimulation induces SAM domain and HD domain-containing protein 1 (SAMHD1) phosphorylation due to cell cycle entry, relieving an early block to infection. Perturbation of the pathways downstream of IL-15 receptor (IL-15R) indicated that SAMHD1 phosphorylation after IL-15 stimulation is JAK dependent. Treating CD4+ T cells with Ruxolitinib, an inhibitor of JAK1 and JAK2, effectively blocked IL-15–induced SAMHD1 phosphorylation and protected CD4+ T cells from HIV infection. Using high-resolution single-cell immune profiling using mass cytometry by TOF (CyTOF), we found that IL-15 stimulation altered the composition of CD4+ T-cell memory populations by increasing proliferation of memory CD4+ T cells, including CD4+ T memory stem cells (TSCM). IL-15–stimulated CD4+ TSCM, harboring phosphorylated SAMHD1, were preferentially infected. We propose that IL-15 plays a pivotal role in creating a self-renewing, persistent HIV reservoir by facilitating infection of CD4+ T cells with stem cell-like properties. Time-limited interventions with JAK1 inhibitors, such as Ruxolitinib, should prevent the inactivation of the endogenous restriction factor SAMHD1 and protect this long-lived CD4+ T-memory cell population from HIV infection.

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