Differential PI3Kδ Signaling in CD4+ T-cell Subsets Enables Selective Targeting of T Regulatory Cells to Enhance Cancer Immunotherapy

Background: Immune non-responders (INR) are HIV+, ART-controlled (>2 yrs) people who fail to reconstitute their CD4 T cell numbers. Systemic inflammation and markers of T cell senescence and exhaustion are observed in INR. This study aims to investigate T cell senescence and exhaustion and their possible association with soluble immune mediators and to understand the immune profile of HIV-infected INR. Selected participants were <50 years old to control for the confounder of older age.Methods: Plasma levels of IL-6, IP10, sCD14, sCD163, and TGF-β and markers of T cell exhaustion (PD-1, TIGIT) and senescence (CD57, KLRG-1) were measured in ART-treated, HIV+ participants grouped by CD4 T cell counts (n = 63). Immune parameters were also measured in HIV-uninfected, age distribution-matched controls (HC; n = 30). Associations between T cell markers of exhaustion and senescence and plasma levels of immune mediators were examined by Spearman rank order statistics.Results: Proportions of CD4 T cell subsets expressing markers of exhaustion (PD-1, TIGIT) and senescence (CD57, KLRG-1) were elevated in HIV+ participants. When comparing proportions between INR and IR, INR had higher proportions of CD4 memory PD-1+, EM CD57+, TEM TIGIT+ and CD8 EM and TEM TIGIT+ cells. Plasma levels of IL-6, IP10, and sCD14 were elevated during HIV infection. IP10 was higher in INR. Plasma TGF-β levels and CD4 cycling proportions of T regulatory cells were lower in INR. Proportions of CD4 T cells expressing TIGIT, PD-1, and CD57 positively correlated with plasma levels of IL-6. Plasma levels of TGF-β negatively correlated with proportions of TIGIT+ and PD-1+ T cell subsets.Conclusions: INR have lower levels of TGF-β and decreased proportions of cycling CD4 T regulatory cells and may have difficulty controlling inflammation. IP10 is elevated in INR and is linked to higher proportions of T cell exhaustion and senescence seen in INR.

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Sex Disparity in Cord Blood FoxP3+ CD4 T Regulatory Cells in Infants Exposed to Malaria In Utero

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx022 ◽

2017 ◽

Vol 4 (1) ◽

Cited By ~ 7

Author(s):

Mary Prahl ◽

Prasanna Jagannathan ◽

Tara I. McIntyre ◽

Ann Auma ◽

Samuel Wamala ◽

...

Keyword(s):

T Cell ◽

Cord Blood ◽

Disease Susceptibility ◽

T Regulatory Cells ◽

In Utero ◽

T Cell Subsets ◽

Cd4 T Cell ◽

Regulatory Cells ◽

Malaria Exposure ◽

Sex Disparity

Abstract Sex differences in the immune response and in infectious disease susceptibility have been well described, although the mechanisms underlying these differences remain incompletely understood. We evaluated the frequency of cord blood CD4 T cell subsets in a highly malaria-exposed birth cohort of mother-infant pairs in Uganda by sex. We found that frequencies of cord blood regulatory T cell ([Treg] CD4+CD25+FoxP3+CD127lo/−) differed by infant sex, with significantly lower frequencies of Tregs in female than in male neonates (P = .006). When stratified by in utero malaria exposure status, this difference was observed in the exposed, but not in the unexposed infants.

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The Role of CD4 T Cells in the Pathogenesis of Murine AIDS

Journal of Virology ◽

10.1128/jvi.02711-05 ◽

2006 ◽

Vol 80 (12) ◽

pp. 5777-5789 ◽

Cited By ~ 20

Author(s):

Wen Li ◽

William R. Green

Keyword(s):

T Cells ◽

T Cell ◽

Nude Mice ◽

Cd4 T Cells ◽

T Regulatory Cells ◽

T Cell Subsets ◽

Cd4 T Cell ◽

Regulatory Cells ◽

Murine Aids

ABSTRACT LP-BM5, a retroviral isolate, induces a disease featuring retrovirus-induced immunodeficiency, designated murine AIDS (MAIDS). Many of the features of the LP-BM5-induced syndrome are shared with human immunodeficiency virus-induced disease. For example, CD4 T cells are critical to the development of MAIDS. In vivo depletion of CD4 T cells before LP-BM5 infection rendered genetically susceptible B6 mice MAIDS resistant. Similarly, MAIDS did not develop in B6.nude mice. However, if reconstituted with CD4 T cells, B6.nude mice develop full-blown MAIDS. Our laboratory has shown that the interaction of B and CD4 T cells that is central to MAIDS pathogenesis requires ligation of CD154 on CD4 T cells with CD40 on B cells. However, it is not clear which additional characteristics of the phenotypically and functionally heterogeneous CD4 T-cell compartment are required. Here, in vivo adoptive transfer experiments using B6.nude recipients are employed to compare the pathogenic abilities of CD4 T-cell subsets defined on the basis of cell surface phenotypic or functional differences. Th1 and Th2 CD4 T cells equally supported MAIDS induction. The rare Thy1.2 − CD4 subset that expands upon LP-BM5 infection was not necessary for MAIDS. Interestingly, CD45RBlow CD4 T cells supported significantly less disease than CD45RBhigh CD4 T cells. Because the decreased MAIDS pathogenesis could not be attributed to inhibition by CD45RBlow CD25+ natural T-regulatory cells, an intrinsic property of the CD45RBlow cells appeared responsible. Similarly, there was no evidence that natural T-regulatory cells played a role in LP-BM5-induced pathogenesis in the context of the intact CD4 T-cell population.

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Phosphoantigen-activated Vγ2Vδ2 T cells antagonize IL-2–induced CD4+CD25+Foxp3+ T regulatory cells in mycobacterial infection

Blood ◽

10.1182/blood-2008-06-162792 ◽

2009 ◽

Vol 113 (4) ◽

pp. 837-845 ◽

Cited By ~ 55

Author(s):

Guangming Gong ◽

Lingyun Shao ◽

Yunqi Wang ◽

Crystal Y. Chen ◽

Dan Huang ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Treatment Regimen ◽

T Regulatory Cells ◽

Mycobacterial Infection ◽

T Cell Subsets ◽

Regulatory Cells ◽

Ifn Γ ◽

Vγ2vδ2 T Cells

Abstract Although Foxp3+ T regulatory cells (Tregs) are well documented for their ability to suppress various immune cells, T-cell subsets capable of counteracting Tregs have not been demonstrated. Here, we assessed phosphoantigen-activated Vγ2Vδ2 T cells for the ability to interplay with Tregs in the context of mycobacterial infection. A short-term IL-2 treatment regimen induced marked expansion of CD4+CD25+Foxp3+ T cells and subsequent suppression of mycobacterium-driven increases in numbers of Vγ2Vδ2 T cells. Surprisingly, activation of Vγ2Vδ2 T cells by adding phosphoantigen Picostim to the IL-2 treatment regimen down-regulated IL-2–induced expansion of CD4+CD25+Foxp3+ T cells. Consistently, in vitro activation of Vγ2Vδ2 T cells by phosphoantigen plus IL-2 down-regulated IL-2–induced expansion of CD4+CD25+Foxp3+ T cells. Interestingly, anti–IFN-γ–neutralizing antibody, not anti–TGF-β or anti–IL-4, reduced the ability of activated Vγ2Vδ2 T cells to down-regulate Tregs, suggesting that autocrine IFN-γ and its network contributed to Vγ2Vδ2 T cells' antagonizing effects. Furthermore, activation of Vγ2Vδ2 T cells by Picostim plus IL-2 treatment appeared to reverse Treg-driven suppression of immune responses of phosphoantigen-specific IFNγ+ or perforin+ Vγ2Vδ2 T cells and PPD-specific IFNγ+αβ T cells. Thus, phos-phoantigen activation of Vγ2Vδ2 T cells antagonizes IL-2–induced expansion of Tregs and subsequent suppression of Ag-specific antimicrobial T-cell responses in mycobacterial infection.

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Lentiviral Engineered T Regulatory Cells Effectively Inhibit Lymphocytes Alloreactivity across Major HLA Barriers

Blood ◽

10.1182/blood.v112.11.3515.3515 ◽

2008 ◽

Vol 112 (11) ◽

pp. 3515-3515

Author(s):

Dario Sangiolo ◽

Noela Jordaney ◽

Giulia Mesiano ◽

Paola Circosta ◽

Angela Elia ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Culture Medium ◽

T Regulatory Cells ◽

Stable Expression ◽

T Cell Subsets ◽

Cell Transplant ◽

Regulatory Cells ◽

Cd4 Cells

Abstract Adoptive immunotherapy strategies enrolling T regulatory cells (Tregs) might have a great potential in modulating donor T cells alloreactivity after Hematopoetic Cell Transplant (HCT). In murine models of HCT Tregs were shown to promote engraftment and contribute controlling graft versus host disease (GVHD) while still not conclusive data are available on humans. Ex-vivo engineering conventional CD4+ T cells to over-express the transcription factor FOXP3 is an intriguing approach to overcome the main difficulty of obtaining large amount of Tregs for experimental studies. Reports of retrovirus-mediated expression of FOXP3 not consistently resulted in functional Tregs while, recently, a lentivirus-mediated strategy was successfully reported to result in homogeneous and stable expression of FOXP3. Lentiviral transduced Tregs were able to suppress a polyclonal proliferation of CD4 purified lymphocytes stimulated with soluble Ab anti-CD3. In our study we generated lentiviral engineered Tregs (eng-Tregs) and investigated their inhibitory effect on unselected lymphocytes alloreactivity across major HLA barriers. Within the bulk lymphocytes population we separately tracked the suppressive influence of eng-Tregs on both CD4+ and CD8+ T cells. To obtain eng-Tregs, CD4+ T cells were purified from healthy donors and transduced with a bidirectional lentiviral vector encoding for FOXP3 and the truncated Nerve Growth Factor Receptor (ΔNGFR). Prior to transduction CD4+ cells were activated for 72 hours with IL2 (100U/ml), IL7 (20ng/ml) and soluble Ab anti-CD3 (200 ng/ml, only IL2 was added to the culture medium after transduction. The lentiviral transduction efficiency ranged from 8 to 25%, ΔNGFR+ T cells were positively selected and tested for their ability to suppress a mixed lymphocyte reaction across major HLA barriers. Effector peripheral blood mononuclear cells (PBMC) were collected from the same donors from whom eng-Tregs were generated. Effector PBMC were stained with CFSE in oder to separately track the alloreactive proliferation of both CD8+ and CD4+ subsets of T cells. Eng-Tregs were added on day 0 and HLA-mismatched irradiated PBMC were used as stimulators; both eng-Tregs and irradiated stimulators were used in a 1:1 ratio with the effectors. No cytokines or additional soluble stimulators were added to the MLR culture medium. The alloreactive proliferation of T cell subsets was determined by evaluating the logarithmic decrease of CFSE fluorescence intensity. The flow cytometry analysis on day +7 showed that alloreactive proliferation of both CD4+ and CD8+ effector cells was significantly inhibited (>75%) by the addition of eng-Tregs compared to controls. In order to rule out a possible role played by the naturally present Tregs (nat-Tregs), the effectors were depleted of the CD4+CD25high subpopulation before the MLR started. The observed alloreactive proliferation was higher after the depletion of nat-Tregs but still it could be significantly inhibited by the addition of eng-Tregs. Eng-Tregs did not significantly expanded when cultured in vitro (up to 2 weeks) with IL2 (100U/ml) but maintained a stable expression of the transgene and retained their suppressive capacity. Our data show that lentiviral engineered Tregs can efficiently down-modulate both CD4+ and CD8+ T cell alloreactivity across major HLA barriers. The observed independence from the presence of nat-Tregs might be important in future experimental HCT settings where the adoptive infusion of eng-Tregs might encounter a great variability in the number and activity of recipient’s nat-Tregs. The possibility of transducing a potentially unlimited number of CD4+ cells makes this strategy appealing for future pre-clinical studies to control GVHD in HCT settings.

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