scholarly journals Mucosal immune stimulation with HSV-2 and polyICLC boosts control of viremia in SIVΔNef vaccinated rhesus macaques with breakthrough SIV infection

2020 ◽  
Author(s):  
Meropi Aravantinou ◽  
Olga Mizenina ◽  
Thilo Brill ◽  
Jessica Kenney ◽  
Christine Timmons ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Immune Activation ◽  
Vaccine Efficacy ◽  
Cd4 T Cells ◽  
Hiv Vaccine ◽  
Live Attenuated Vaccine ◽  
Siv Infection ◽  
The Impact

ABSTRACTDevelopment of an effective human immunodeficiency virus (HIV) vaccine is among the highest priorities in the biomedical research agenda. Adjuvants enhance vaccine efficacy, but in the case of HIV, strong or inappropriate immune activation may undermine protection by increasing HIV susceptibility. Co-infection with immunomodulatory pathogens may also impact vaccine efficacy. In the rhesus macaque rectal SIVΔNef live attenuated vaccine model, we utilized a low virulence HSV-2 infection and the double-stranded RNA viral mimic polyICLC as tools to probe the effects of distinct types of immune activation on HIV vaccine efficacy and explore novel correlates of protection from wild type SIV. Rectally administered HSV-2 and polyICLC impacted the protection conferred by mucosal SIVΔNef vaccination by favoring partial protection in animals with breakthrough infection following virulent SIV challenge (“Controllers”). However, SIVΔNef persistence in blood and tissues did not predict protection in this rectal immunization and challenge model. Non-controllers had similar SIVΔNef viremia as completely protected macaques, and while they tended to have less replication competent SIVΔNef in lymph nodes, controllers had no recoverable virus in the lymph nodes. Non-controllers differed from protected macaques immunologically by having a greater frequency of pro-inflammatory CXCR3+CCR6+ CD4 T cells in blood and a monofunctional IFNγ-dominant CD8 T cell response in lymph nodes. Controller phenotype was associated with heightened IFNα production during acute SIV infection and a greater frequency of CXCR5+ CD4 T cells in blood pre-challenge despite a lower frequency of cells with the T follicular helper (Tfh) cell phenotype in blood and lymph nodes. Our results establish novel correlates of immunological control of SIV infection while reinforcing the potential importance of T cell functionality and location in SIVΔNef efficacy. Moreover, this work highlights that triggering of mucosal immunity can aid mucosal vaccine strategies rather than undermine protection.AUTHOR SUMMARYAn efficacious HIV vaccine is essential to contain the HIV pandemic. Vaccine-mediated protection from HIV may be either enhanced or obstructed by mucosal immune activation; thus, the impact of adjuvants and underlying co-infections that lead to immune activation needs to be evaluated. Using the SIV macaque model, we set out to study the impact of underlying infection with HSV-2 or treatment with the adjuvant polyICLC on rectal immunization with the live attenuated vaccine SIVΔNef. We found that neither stimulus impacted complete protection from SIV; however, the combination of HSV-2 and polyICLC improved control of infection in animals that were not completely protected. Compared with non-controller macaques, controllers had less inflammatory T cells before SIV challenge as well as greater gene expression of IFNα and more functional SIV-specific T cells after infection. The results add to our understanding of the mechanisms of SIVΔNef protection and demonstrate that mucosal immune activation does not necessarily undermine protection in mucosal vaccination against HIV.

scholarly journals Differential Dynamics of Regulatory T-Cell and Th17 Cell Balance in Mesenteric Lymph Nodes and Blood following Early Antiretroviral Initiation during Acute Simian Immunodeficiency Virus Infection

2019 ◽  
Vol 93 (19) ◽  
Author(s):  
Alexis Yero ◽  
Omar Farnos ◽  
Henintsoa Rabezanahary ◽  
Gina Racine ◽  
Jérôme Estaquier ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Immune Activation ◽  
Rhesus Macaques ◽  
Mesenteric Lymph Nodes ◽  
Tissue Fibrosis ◽  
Mesenteric Lymph ◽  
Immunodeficiency Virus ◽  
Siv Infection

ABSTRACT Increased frequencies of immunosuppressive regulatory T cells (Tregs) are associated with gut lymphoid tissue fibrosis and dysfunction which, in turn, contribute to disease progression in chronic simian immunodeficiency virus/human immunodeficiency virus (SIV/HIV) infection. Mesenteric lymph nodes (MLNs), which drain the large and small intestine, are critical sites for the induction and maintenance of gut mucosal immunity. However, the dynamics of Tregs in MLNs are not well understood due to the lack of accessibility to these tissues in HIV-infected individuals. Here, the dynamics of Tregs in blood and MLNs were assessed in SIV-infected rhesus macaques (RMs) following early antiretroviral drug (ARV) initiation. Early ARV initiation reduced T-cell immune activation, as assessed by HLA-DR/CD39 expression, and prevented the depletion of memory CCR6+ Th17 cells in both blood and MLNs. Untreated animals showed higher frequencies of Tregs, CD39+ Tregs, thymic Tregs, and new memory CD4 populations sharing similarity with Tregs as CTLA4+ PD1– and CTLA4+ PD1– FoxP3+ T cells. Despite early ARV treatment, the frequencies of these Treg subsets remained unchanged within the MLNs and, in contrast to blood normalization, the Th17/Treg ratio remained distorted in MLNs. Furthermore, our results highlighted that the expressions of IDO-1, TGFβ1 and collagen-1 mRNA remained unchanged in MLN of ARV-treated RMs. ARV interruption did not affect T-cell immune activation and Th17/Treg ratios in MLN. Altogether, our data demonstrated that early ARV initiation within the first few days of SIV infection is unable to reduce the frequencies and homing of various subsets of Tregs within the MLNs which, in turn, may result in tissue fibrosis, impairment in MLN function, and HIV persistence. IMPORTANCE Tregs contribute to SIV/HIV disease progression by inhibition of antiviral specific responses and effector T-cell proliferation. Tregs also cause tissue fibrosis via transforming growth factor β1 production and collagen deposition, which are associated with microbial translocation and generalized immune activation. Early ARV initiation upon viral exposure is recommended globally and results in improved immune function recovery and reduced viral persistence. Here, using an acute SIV infection model of rhesus macaques, we demonstrated for the first time that despite clear improvements in mucosal CD4 T cells, in contrast to blood, Treg frequencies in MLNs remained elevated following early ARV initiation. The particular Th17/Treg balance observed in MLNs can contribute, in part, to the maintenance of mucosal fibrosis during suppressive ARV treatment. Our results provide a better understanding of gut mucosal immune dynamics following early ARV initiation. These findings suggest that Treg-based treatments could serve as a novel immunotherapeutic approach to decrease gut mucosal damage during SIV/HIV infections.

scholarly journals Strong TH1-biased CD4 T cell responses are associated with diminished SIV vaccine efficacy

2019 ◽  
Vol 11 (519) ◽  
pp. eaav1800 ◽  
Author(s):  
Venkateswarlu Chamcha ◽  
Pradeep B. J. Reddy ◽  
Sunil Kannanganat ◽  
Courtney Wilkins ◽  
Sailaja Gangadhara ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Vaccine Efficacy ◽  
Cd4 T Cells ◽  
T Cell Responses ◽  
Hiv Vaccine ◽  
Cd4 T Cell ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Hiv Acquisition

Activated CD4 T cells are a major target of HIV infection. Results from the STEP HIV vaccine trial highlighted a potential role for total activated CD4 T cells in promoting HIV acquisition. However, the influence of vaccine insert-specific CD4 T cell responses on HIV acquisition is not known. Here, using the data obtained from four macaque studies, we show that the DNA prime/modified vaccinia Ankara boost vaccine induced interferon γ (IFNγ+) CD4 T cells [T helper 1 (TH1) cells] rapidly migrate to multiple tissues including colon, cervix, and vaginal mucosa. These mucosal TH1 cells persisted at higher frequencies and expressed higher density of CCR5, a viral coreceptor, compared to cells in blood. After intravaginal or intrarectal simian immunodeficiency virus (SIV)/simian-human immunodeficiency virus (SHIV) challenges, strong vaccine protection was evident only in animals that had lower frequencies of vaccine-specific TH1 cells but not in animals that had higher frequencies of TH1 cells, despite comparable vaccine-induced humoral and CD8 T cell immunity in both groups. An RNA transcriptome signature in blood at 7 days after priming immunization from one study was associated with induction of fewer TH1-type CD4 cells and enhanced protection. These results demonstrate that high and persisting frequencies of HIV vaccine–induced TH1-biased CD4 T cells in the intestinal and genital mucosa can mitigate beneficial effects of protective antibodies and CD8 T cells, highlighting a critical role of priming immunization and vaccine adjuvants in modulating HIV vaccine efficacy.

scholarly journals The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism

Immuno ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 119-131
Author(s):  
Jana Palmowski ◽  
Kristina Gebhardt ◽  
Thomas Reichel ◽  
Torsten Frech ◽  
Robert Ringseis ◽  
...  
Keyword(s):  
T Cells ◽  
Oxygen Consumption ◽  
T Cell ◽  
Real Time ◽  
Cd4 T Cells ◽  
Cell Metabolism ◽  
Cd4 T Cell ◽  
Autologous Serum ◽  
Cell Phenotype ◽  
The Impact

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.

scholarly journals Probiotic supplementation reduces inflammatory profiles but does not prevent oral immune perturbations during SIV infection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rhianna Jones ◽  
Kyle Kroll ◽  
Courtney Broedlow ◽  
Luca Schifanella ◽  
Scott Smith ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Rhesus Macaques ◽  
Oral Microbiome ◽  
Probiotic Supplementation ◽  
Siv Infection ◽  
Anti Inflammatory

AbstractHIV/SIV infections lead to massive loss of mucosal CD4 + T cells and breakdown of the epithelial mucosa resulting in severe microbial dysbiosis and chronic immune activation that ultimately drive disease progression. Moreover, disruption of one of the most understudied mucosal environments, the oral cavity, during HIV-induced immunosuppression results in significant microbial and neoplastic co-morbidities and contributes to and predicts distal disease complications. In this study we evaluated the effects of oral probiotic supplementation (PBX), which can stimulate and augment inflammatory or anti-inflammatory pathways, on early SIV infection of rhesus macaques. Our study revealed that similar to the GI mucosae, oral CD4 + T cells were rapidly depleted, and as one of the first comprehensive analyses of the oral microflora in SIV infection, we also observed significant modulation among two genera, Porphyromonas and Actinobacillus, early after infection. Interestingly, although PBX therapy did not substantially protect against oral dysbiosis or ameliorate cell loss, it did somewhat dampen inflammation and T cell activation. Collectively, these data provide one of the most comprehensive evaluations of SIV-induced changes in oral microbiome and CD4 + T cell populations, and also suggest that oral PBX may have some anti-inflammatory properties in lentivirus infections.

scholarly journals Increased Loss of CCR5+ CD45RA− CD4+ T Cells in CD8+ Lymphocyte-Depleted Simian Immunodeficiency Virus-Infected Rhesus Monkeys

2008 ◽  
Vol 82 (11) ◽  
pp. 5618-5630 ◽  
Author(s):  
Ronald S. Veazey ◽  
Paula M. Acierno ◽  
Kimberly J. McEvers ◽  
Susanne H. C. Baumeister ◽  
Gabriel J. Foster ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Simian Immunodeficiency Virus ◽  
Peripheral Blood ◽  
T Cell Responses ◽  
Lymphocyte Depletion ◽  
Cell Responses ◽  
Immunodeficiency Virus ◽  
Siv Infection

ABSTRACT Previously we have shown that CD8+ T cells are critical for containment of simian immunodeficiency virus (SIV) viremia and that rapid and profound depletion of CD4+ T cells occurs in the intestinal tract of acutely infected macaques. To determine the impact of SIV-specific CD8+ T-cell responses on the magnitude of the CD4+ T-cell depletion, we investigated the effect of CD8+ lymphocyte depletion during primary SIV infection on CD4+ T-cell subsets and function in peripheral blood, lymph nodes, and intestinal tissues. In peripheral blood, CD8+ lymphocyte-depletion changed the dynamics of CD4+ T-cell loss, resulting in a more pronounced loss 2 weeks after infection, followed by a temporal rebound approximately 2 months after infection, when absolute numbers of CD4+ T cells were restored to baseline levels. These CD4+ T cells showed a markedly skewed phenotype, however, as there were decreased levels of memory cells in CD8+ lymphocyte-depleted macaques compared to controls. In intestinal tissues and lymph nodes, we observed a significantly higher loss of CCR5+ CD45RA− CD4+ T cells in CD8+ lymphocyte-depleted macaques than in controls, suggesting that these SIV-targeted CD4+ T cells were eliminated more efficiently in CD8+ lymphocyte-depleted animals. Also, CD8+ lymphocyte depletion significantly affected the ability to generate SIV Gag-specific CD4+ T-cell responses and neutralizing antibodies. These results reemphasize that SIV-specific CD8+ T-cell responses are absolutely critical to initiate at least partial control of SIV infection.

scholarly journals Intravenous Arginine Administration Benefits CD4+ T-Cell Homeostasis and Attenuates Liver Inflammation in Mice with Polymicrobial Sepsis

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1047
Author(s):  
Chiu-Li Yeh ◽  
Sharon Angela Tanuseputero ◽  
Jin-Ming Wu ◽  
Yi-Ru Tseng ◽  
Po-Jen Yang ◽  
...  
Keyword(s):  
T Cells ◽  
Single Dose ◽  
Lymph Node ◽  
T Cell ◽  
Lymph Nodes ◽  
Cd4 T Cells ◽  
Cd4 T Cell ◽  
Liver Inflammation ◽  
Aortic Lymph Node ◽  
Inos Inhibitor

This study investigated the effects of a single dose of arginine (Arg) administration at the beginning of sepsis on CD4+ T-cell regulation and liver inflammation in C57BL/6J mice. Mice were divided into normal control (NC), sham (SH), sepsis saline (SS), and sepsis Arg (SA) groups. An inducible nitric oxide (NO) synthase (iNOS) inhibitor was administered to additional sepsis groups to evaluate the role of NO during sepsis. Sepsis was induced using cecal ligation and puncture (CLP). The SS and SA groups received saline or Arg (300 mg/kg body weight) via tail vein 1 h after CLP. Mice were euthanized at 12 and 24 h post-CLP. Blood, para-aortic lymph nodes, and liver tissues were collected for further measurement. The findings showed that sepsis resulted in decreases in blood and para-aortic lymph node CD4+ T-cell percentages, whereas percentages of interleukin (IL)-4- and IL-17-expressing CD4+ T cells were upregulated. Compared to the SS group, Arg administration resulted in maintained circulating and para-aortic lymph node CD4+ T cells, an increased Th1/Th2 ratio, and a reduced Th17/Treg ratio post-CLP. In addition, levels of plasma liver injury markers and expression of inflammatory genes in liver decreased. These results suggest that a single dose of Arg administered after CLP increased Arg availability, sustained CD4+ T-cell populations, elicited more-balanced Th1/Th2/Th17/Treg polarization in the circulation and the para-aortic lymph nodes, and attenuated liver inflammation in sepsis. The favorable effects of Arg were abrogated when an iNOS inhibitor was administered, which indicated that NO may be participated in regulating the homeostasis of Th/Treg cells and subsequent liver inflammation during sepsis.

scholarly journals Allergen-Induced C5a/C5aR1 Axis Activation in Pulmonary CD11b+ cDCs Promotes Pulmonary Tolerance through Downregulation of CD40

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 300 ◽  
Author(s):  
Konstantina Antoniou ◽  
Fanny Ender ◽  
Tillman Vollbrandt ◽  
Yves Laumonnier ◽  
Franziska Rathmann ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
T Cell Proliferation ◽  
C5a Receptor ◽  
The Impact

Activation of the C5/C5a/C5a receptor 1 (C5aR1) axis during allergen sensitization protects from maladaptive T cell activation. To explore the underlying regulatory mechanisms, we analyzed the impact of C5aR1 activation on pulmonary CD11b+ conventional dendritic cells (cDCs) in the context of house-dust-mite (HDM) exposure. BALB/c mice were intratracheally immunized with an HDM/ovalbumin (OVA) mixture. After 24 h, we detected two CD11b+ cDC populations that could be distinguished on the basis of C5aR1 expression. C5aR1− but not C5aR1+ cDCs strongly induced T cell proliferation of OVA-reactive transgenic CD4+ T cells after re-exposure to antigen in vitro. C5aR1− cDCs expressed higher levels of MHC-II and CD40 than their C5aR1+ counterparts, which correlated directly with a higher frequency of interactions with cognate CD4+ T cells. Priming of OVA-specific T cells by C5aR1+ cDCs could be markedly increased by in vitro blockade of C5aR1 and this was associated with increased CD40 expression. Simultaneous blockade of C5aR1 and CD40L on C5aR1+ cDCs decreased T cell proliferation. Finally, pulsing with OVA-induced C5 production and its cleavage into C5a by both populations of CD11b+ cDCs. Thus, we propose a model in which allergen-induced autocrine C5a generation and subsequent C5aR1 activation in pulmonary CD11b+ cDCs promotes tolerance towards aeroallergens through downregulation of CD40.

scholarly journals In Vivo Detection of Dendritic Cell Antigen Presentation to CD4+ T Cells

1997 ◽  
Vol 185 (12) ◽  
pp. 2133-2141 ◽  
Author(s):  
Elizabeth Ingulli ◽  
Anna Mondino ◽  
Alexander Khoruts ◽  
Marc K. Jenkins
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
T Cell Activation ◽  
Cd4 T Cells ◽  
Cell Activation ◽  
Delayed Type Hypersensitivity ◽  
Physical Interaction

Although lymphoid dendritic cells (DC) are thought to play an essential role in T cell activation, the initial physical interaction between antigen-bearing DC and antigen-specific T cells has never been directly observed in vivo under conditions where the specificity of the responding T cells for the relevant antigen could be unambiguously assessed. We used confocal microscopy to track the in vivo location of fluorescent dye-labeled DC and naive TCR transgenic CD4+ T cells specific for an OVA peptide–I-Ad complex after adoptive transfer into syngeneic recipients. DC that were not exposed to the OVA peptide, homed to the paracortical regions of the lymph nodes but did not interact with the OVA peptide-specific T cells. In contrast, the OVA peptide-specific T cells formed large clusters around paracortical DC that were pulsed in vitro with the OVA peptide before injection. Interactions were also observed between paracortical DC of the recipient and OVA peptide-specific T cells after administration of intact OVA. Injection of OVA peptide-pulsed DC caused the specific T cells to produce IL-2 in vivo, proliferate, and differentiate into effector cells capable of causing a delayed-type hypersensitivity reaction. Surprisingly, by 48 h after injection, OVA peptide-pulsed, but not unpulsed DC disappeared from the lymph nodes of mice that contained the transferred TCR transgenic population. These results demonstrate that antigen-bearing DC directly interact with naive antigen-specific T cells within the T cell–rich regions of lymph nodes. This interaction results in T cell activation and disappearance of the DC.

NK Cells Suppress Gvhd by Directly Inhibiting Activated Alloreactive T Cells through An NKG2D-Mediated Mechanism

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 61-61 ◽  
Author(s):  
Janelle A Olson ◽  
Dennis B Leveson-Gower ◽  
Jeanette Baker ◽  
Andreas Beilhack ◽  
Robert Negrin
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Nk Cells ◽  
Nk Cell ◽  
Cell Transplant ◽  
Donor Strain ◽  
Specific Lysis ◽  
Donor T Cells ◽  
The Impact

Abstract Natural Killer (NK) cells have the ability to suppress graft-versus-host disease (GVHD) while inducing a graft-versus-tumor response (GVT) following murine allogeneic bone marrow transplantation (BMT). Prior studies have shown that NK cells suppress GVHD by eliminating recipient dendritic cells. To assess additional potential mechanisms of GVHD suppression we evaluated the impact of donor NK cells on GVHD-inducing donor T cells. Interleukin-2 activated allogeneic NK cells isolated from C57Bl6 (H-2b) or FVB (H-2q) animals were transplanted along with T cell-depleted bone marrow (TCD-BM) into lethally irradiated BALB/c (H-2d) mice, followed 2 days later by luciferase-expressing CD4+ and CD8+ conventional T cells (Tcon) from the same donor strain (Tcon+NK group). Control mice received TCD-BM on day 0, and luciferase-expressing T cells on day 2 after transplant (Tcon group). Bioluminescence imaging of Tcon+NK mice revealed a significantly lower T cell bioluminescent signal compared to Tcon mice (p=0.01 on day 5 post T cell transplant). We assessed the impact of NK cells on donor T cell activation and proliferation. CFSE proliferation analysis of alloreactive CD4 and CD8 T cells reisolated on day 4 post transplant showed a decreased percentage of dividing donor T cells in the Tcon+NK group. A reduced percentage of T cells in the Tcon+NK group as compared to the Tcon group expressed the T cell activation marker CD25 (11% and 49%, respectively, among donor CD4) and a reduced percentage of T cells from the Tcon+NK group down-regulated CD62L. Reisolated donor T cell numbers were reduced in the Tcon+NK mice compared to Tcon control mice. The impact of donor NK cells on donor Tcon function was addressed by intracellular cytokine staining. Fewer donor T cells reisolated from the spleen and lymph nodes of Tcon+NK mice produced the proinflammatory cytokines IFN-γ and IL-2 on day 3 after transplant. These observations can be explained by an NK cell-mediated induction of apoptosis in the donor Tcon. T cells reisolated from the peripheral lymph nodes of Tcon+NK animals at day 4 post transplant stained higher for the TUNEL apoptosis marker than those from Tcon mice (p<0.0001 for CD4 and CD8). To determine if this increase in apoptosis was due to a direct interaction between the donor T cells and NK cells, donor Tcon were reisolated from transplanted mice and used as targets in a killing assay. We demonstrated direct, specific lysis of these reisolated T cells by activated NK cells, both of which are from the donor strain and thus syngeneic to each other. Donor T cells reisolated from the lymph nodes of transplanted mice upregulated the NKG2D ligand Rae1γ as compared to naïve T cells, as shown by FACS. Further, use of an NKG2D-blocking antibody decreased the specific lysis of donor Tcon reisolated from the lymph nodes by activated NK cells in the in vitro killing assay, compared to an isotype control antibody (p=0.004). These data indicate that NK cells are causing direct, NKG2D-dependent lysis of alloreactive donor T cells in vivo during GVHD induction. Recent data from our laboratory has shown a lack of NKG2D ligand expression on GVHD target tissues in irradiated recipient mice. The tissue-specific expression of NKG2D ligands may explain why allogeneic NK cells do not cause GVHD but do impact donor T cells. We further investigated the ability of T cells in this model to elicit a GVT effect in the presence or absence of NK cells. Using a luciferase-expressing A20 lymphoma cell line, we demonstrated tumor clearance in groups receiving A20+Tcon and A20+Tcon+NK, as measured by A20 bioluminescence signal. Animals in the A20+Tcon+NK group had a lower peak bioluminescent signal than animals in the A20+Tcon group (p=0.03 on day 4 post T cell transplant), indicating an additive GVT effect of the T cells and NK cells. Thus, the T cells in this model are capable of mounting an effective GVT response. In addition to the established mechanism of NK cell-mediated elimination of recipient dendritic cells, we have demonstrated a novel mechanism of NK cell action in murine models of GVHD, whereby the donor NK cells inhibit T cell proliferation and activation and cause direct, NKG2D-mediated lysis of alloreactive donor T cells.

Follicular Lymphoma Tumor Infiltrating T-Helper (Th) Cells Have the Same Intrinsic Polyfunctional Response Potential Upon Stimulation as Do Reactive and Normal Lymph Node Th Cells Despite Having Skewed Differentiation; Implications for Immunotherapy

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3119-3119
Author(s):  
Shannon P. Hilchey ◽  
Alexander F. Rosenberg ◽  
Ollivier Hyrien ◽  
Shelley Secor-Socha ◽  
Matthew R. Cochran ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Lymph Nodes ◽  
Follicular Lymphoma ◽  
Cd4 T Cells ◽  
Th2 Cells ◽  
T Helper ◽  
Th Cells ◽  
Cytokine Profiles ◽  
Th1 And Th2

Abstract Abstract 3119 Tumor infiltrating T-cells tend to be hypo-functional and this loss of function may be due to intrinsic T-cell defects, impaired antigen (Ag) presentation, and/or suppression induced by extrinsic components of the microenvironment, such as regulatory T-cells (Tregs). Each of these potential mechanisms has distinct implications on the potential efficacy of immunotherapy. To determine the functional potential of follicular lymphoma (FL) derived T-cells, we analyzed, by flow cytometry, T helper (Th) subsets and Staphylococcus enterotoxin B (SEB)-induced cytokine profiles of single cell suspensions from FL involved nodes (FL; n=8), reactive lymph nodes (RLN; n=7) and normal lymph nodes (NLN; n=6; obtained during vascular surgery). SEB was used as it directly triggers the T-cell receptor, abrogating the need for Ag presentation, and overcomes Treg mediated suppression. Herein we show that, relative to NLN, FL has decreased proportions of CD4+ T-cells having either a naïve (CD45RA+) or central memory (CD45RA−CCR7+) phenotype but increased proportions of effector memory T-cells (CD45RA−CCR7−). In addition, a higher percentage of pre-stimulation FL CD4+ T-cells show an activated (CD69+) phenotype as compared to that of RLN or NLN. Upon SEB stimulation, the FL CD4+ T-cells, like those from RLN and NLN, show an additional increase in the proportion of CD69+ cells, demonstrating that the FL derived CD4+ T-cells can be activated even further. We also show that upon stimulation with SEB; (a) the proportion of Th1 cells (IL-2+IFN-g+IL-4−) in FL is similar to that seen in RLN or NLN; (b) in contrast, we observe an increased frequency of primed uncommitted precursor Thpp cells (IL-2+IFN-g−IL-4−) in FL compared to that seen in either RLN or NLN; (c) an increased proportion of Th2 cells in FL compared with NLN and; (d) an increase in the proportion of Th17 cells in FL compared to that in RLN. Lastly, the proportions of FL Th cells producing 3 or 4 cytokines simultaneously, or poly-functional CD4+ T-cells, (PFT; PFT-3 producing IL-2, IFN-g and TNF-a or PFT-4 producing IL-2, IFN-g, TNF-a and MIP-1b), after SEB stimulation is similar to that seen in RLN or NLN. These data suggest that although there is skewed Th cell differentiation in FL, as compared to that of RLN or NLN, the intrinsic ability of the FL Th cells to elicit a clinically relevant effector response (both a Th1 and Th2 response) is fully preserved. In addition, the retention of effector function of FL Th cells is further supported by the fact that the proportions of these Th cells that have poly-functional cytokine profiles after SEB stimulation is similar in FL as compared to RLN or NLN. Indeed, poly-functionality of Th cells has been shown to correlate with the elicitation of protective immunity after vaccination for infectious diseases. Finally, the proportion of uncommitted Thpp cells after SEB stimulation is highest in FL. Thpp cells are non-polarized and can still differentiate into either Th1 or Th2 cells. They can also produce several chemokines and thus may play a role in shaping the FL microenvironment by recruiting other immune-effector cells as well as developing into Th1 and Th2 cells. Taken together, our data shows that FL Th cells are fully functional within the parameters of our assays, suggesting that these cells are intrinsically capable of mediating effective anti-tumor immune responses after immunotherapy. Therefore the hypo-functionality of FL T-cells is likely due to extrinsic factors which suppress T-cell function in vivo. Thus the challenge is to develop immunotherapeutic strategies that overcome these tumor associated extrinsic mechanisms, resulting in effective anti-tumor immunity. Disclosures: No relevant conflicts of interest to declare.

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