Hyperactive PI3Kδ predisposes naive T cells to activation via aerobic glycolysis programs

Activated phosphoinositide 3-kinaseδsyndrome(APDS)is an autosomal-dominant combined immunodeficiency disorder resulting from pathogenic gain-of-function(GOF)mutations in the PIK3CD gene.Patients with APDS display abnormal T cell homeostasis.However,the mechanisms by which PIK3CD GOF contributes to this feature remain unknown.Here,with a cohort of children with PIK3CD GOF mutations from multiple regions of China and a corresponding CRISPR/Cas9 gene-edited mouse model,we reported that hyperactive PI3Kδdisrupted TNaive cell homeostasis in the periphery by intrinsically promoting the growth,proliferation,and activation of TNaive cells.Our results showed that PIK3CD GOF resulted in loss of the quiescence-associated gene expression profile in naive T cells and promoted naive T cells to overgrow,hyperproliferate and acquire an activated functional status.Naive PIK3CD GOF T cells exhibited an enhanced glycolytic capacity and reduced mitochondrial respiration in the resting or activated state.Blocking glycolysis abrogated the abnormal splenic T cell pool and reversed the overactivated phenotype induced by PIK3CD GOF in vivo and in vitro.These results suggest that enhanced aerobic glycolysis is required for PIK3CD GOF-induced overactivation of naive T cells and provide a potential therapeutic approach for targeting glycolysis to treat patients with APDS as well as other immune disorders.

Effector cells derived from naive T cells used in tumor immunotherapy of mice bearing B16 melanoma

Background Adoptive cell transfer （ACT） immunotherapy has been used clinically for years to treat malignancies.Improving the killing efficiency of effector cells,such as tumor-specific cytotoxic T lymphocytes （CTLs）,is an important component for enhancing the clinical response of cancer immunotherapy.Hence,we explored a novel method for preparing cancer-specific CTLs using naive T lymphocytes.Methods C57BL/6 mice bearing B16 melanoma tumors were pretreated with cyclophosphamide （CTX） by peritoneal injection.The immunosuppressive influence of CTX on tumor regression and the tumor microenvironment was assessed.Naive T cells and T cell pools were isolated via negative selection using immunomagnetic beads.The proliferative potential and cytokine production of different T cell subpopulations were evaluated in vitro.Tumor-specific CTLs derived from naive T cells （naive CD4＋ T cells：naive CD8＋ T cells=2：1） and pooled T cells were generated in vitro,respectively.B16 melanoma-bearing C57BL/6 mice were pretreated with CTX,followed by ACT immunotherapy using dendritic cell-induced CTLs.The homing abilities of the effector cells and interleukin-2 （IL-2）,interferon-y,granzyme B,and perforin mRNA levels in tumor tissues were evaluated,and the change in tumor volume was measured.Results Mice receiving CTX peritoneal pretreatment injections did not display tumor regression compared with control mice.However,a significant downregulation of splenic Tregs and tumor growth factor-β1 （TGF-β1） and interleukin-10 （IL-10） serum levels was observed （P ＜0.05）.Naive T cells showed a stronger proliferative capacity and elevated cytokine production than did pooled T cells （P ＜0.05）.In addition,effector cells generated from naive T cells displayed more potent antitumor activity in vivo than those derived from pooled T cells （P ＜0.05）.Conclusion Effector cells derived from the naive T cells possess a stronger proliferative potential,homing capacity,and enhanced cytokine production,which leads to a superior antitumor response.