IL-7 signaling imparts polyfunctionality and stemness potential to CD4⁺ T cells

Abstract

The functional status of CD4 C T cells is a critical determinant of antitumor immunity. Polyfunctional CD4 C T cells possess the ability to concomitantly produce multiple Th1-type cytokines, exhibiting a functional attribute desirable for cancer immunotherapy. However, the mechanisms by which these cells are induced are neither defined nor it is clear if these cells can be used therapeutically to treat cancer. Here, we report that CD4C T cells exposed to exogenous IL-7 during antigenic stimulation can acquire a polyfunctional phenotype, characterized by their ability to simultaneously express IFNg, IL-2, TNFa and granzyme B. This IL-7-driven polyfunctional phenotype was associated with increased histone acetylation in the promoters of the effector genes, indicative of increased chromatin accessibility. Moreover, forced expression of a constitutively active (CA) form of STAT5 recapitulated IL-7 in inducing CD4 C T-cell polyfunctionality. Conversely, the expression of a dominant negative (DN) form of STAT5 abolished the ability of IL-7 to induce polyfunctional CD4 C T cells. These in-vitro-generated polyfunctional CD4 C T cells can traffic to tumor and expand intratumorally in response to immunization. Importantly, adoptive transfer of polyfunctional CD4C T cells following lymphodepletive chemotherapy was able to eradicate large established tumors. This beneficial outcome was associated with the occurrence of antigen epitope spreading, activation of the endogenous CD8C T cells and persistence of donor CD4 C T cells exhibiting memory stem cell attributes. These findings indicate that IL-7 signaling can impart polyfunctionality and stemness potential to CD4 C T cells, revealing a previously unknown property of IL-7 that can be exploited in adoptive T-cell immunotherapy.

Alteration of Tumor Metabolism by CD4+ T Cells Leads to TNF-α-Dependent Intensification of Oxidative Stress and Tumor Cell Death

“…It was unclear whether polyfunctional CD4+ T cells really relied on TNF-α to promote ROS induction in tumor cells following chemotherapy. We previously reported that antigenic stimulation of CD4+ T cells in the presence of recombinant IL-7 gave rise to polyfunctional CD4+ T cells proficient in TNF-α and IFNγ production (Ding et al, 2016). We prepared polyfunctional CD4+ T cells (pCD4), which were proficient in TNF-α and IFNγ production, and activated control CD4+ T cells (cCD4), which were poor producers of these cytokines (Figure 5F).…”

“…Antioxidants GSHree and mitoTEMPO were used at 6 mM and 100 μM, respectively. To prepare conditional medium from T cells, polyfunctional CD4+ T cells were generated as previously described (Ding et al, 2016). Briefly, splenocytes from HA-specific TCR-Tg mice (6.5) were stimulated with 2 μg/ml HA peptide in the presence or absence of rmIL7.…”

Mesothelin-specific Immune Responses Predict Survival of Patients With Brain Metastasis

“…IL-7 has been shown to increase expansion of circulating human CD4 and CD8 T cells, with a positive effect on T-cell receptor (TCR) repertoire diversification and reduction in Treg numbers ( Sportes et al, 2008 ). Furthermore, recent preclinical studies have shown that IL-7 treatment promotes CD4 T cell poly-functionality leading to tumor containment ( Ding et al, 2016 ). In combination with IL-12 pre-priming of antigen-experienced CD8 T cells, IL-7 can induce cellular proliferation after IL-12 withdrawal ( Johnson et al, 2016 ).…”

Transcriptional Profiling of CD8+ CMV-Specific T Cell Functional Subsets Obtained Using a Modified Method for Isolating High-Quality RNA From Fixed and Permeabilized Cells

“…In this study, we demonstrated that STAT5 activity is required for antigen-induced polyfunctionality and maximal proliferation in healthy subjects, and that a strong association between STAT5 signaling with polyfunctional T cells is maintained in immunosuppressed patients. STAT5 has been shown to play a critical role in antigen-specific effector and memory cell survival and proliferation, although its role in polyfunctional T cell activity has not previously been explored ( 69 – 75 , 83 , 85 , 86 ). STAT5 activity downstream of TCR and/or IL-2 has also been shown to function as a stabilizer of gene regulation initiated following antigen re-exposure ( 84 ).…”

“…Additionally, transfection with constitutively-active STAT5 has been associated with superior anti-tumor activity in mouse models of malignancy, and CAR-T cells engineered toward increased STAT5 activity demonstrate improved proliferation and polyfunctionality while preventing terminal differentiation ( 71 , 72 , 74 , 75 , 86 ). Several studies have also demonstrated that ex-vivo expansion of antigen-specific T cells in the presence of IL-7, an upstream regulator of STAT5 activity, is associated with a STAT5-dependent increase in polyfunctional cells ( 69 – 74 , 85 , 87 – 89 ). This is of particular interest given that polyfunctional T cells have increased surface expression of IL-7R, which regulates IL-7 activity.…”