Research Article: Human CD4 + iNKT cells have highly oxidative metabolism and use glycogen reserves to sustain IFN-? production in nutrient-limited environments
Abstract:
Invariant natural killer T (iNKT) cells are promising candidates for allogeneic cellular immunotherapy, but the metabolic pathways that support their effector function in nutrient-limited tumor microenvironments remain poorly defined. Human iNKT cells segregate into CD4 + and CD4?CD8? double-negative (DN) subsets with distinct functional profiles, yet whether they use divergent metabolic strategies to sustain IFN-? production is unknown. Here we show that in vitro -expanded human CD4 + and DN iNKT cells employ distinct metabolic programs that differentially support IFN-? secretion under nutrient stress. DN iNKT cells exhibit higher Glut1 expression and a more glycolytic phenotype, with IFN-? production that is sensitive to extracellular glucose withdrawal and glycolytic inhibition. In contrast, CD4 + iNKT cells display high spare respiratory capacity, preferentially engage glutamine-supported mitochondrial respiration, and maintain IFN-? production despite glucose deprivation or 2-DG inhibitor treatment. CD4 + iNKT cells generated excess ATP through oxidative metabolism, accumulated intracellular glycogen stores during expansion in vitro , and subsequently mobilized this glycogen to support IFN-? production in tumor-exhausted media. Using a xenograft model of EBV-driven B cell lymphoma, we show that adoptively transferred human CD4 + iNKT cells infiltrate tumors in vivo and are associated with elevated intratumoral IFN-?. These findings identify a distinctive combination of high mitochondrial oxidative capacity, glutamine utilization, and glycogen storage that endows human CD4 + iNKT cells with exceptional metabolic resilience, suggesting that CD4 + iNKT-based products may provide a particularly valuable platform for adoptive cellular immunotherapy.
Introduction:
Invariant natural killer T (iNKT) cells are a conserved population of innate T lymphocytes that can mediate potent anti-tumor effects [reviewed in ( 1 – 3 )]. Unlike conventional T cells, which recognize peptide antigens presented by polymorphic MHC molecules, iNKT cells bear a semi-invariant T cell receptor (TCR) that recognizes lipids and glycolipids as antigens presented by CD1d, a non-classical antigen presenting molecule that has minimal polymorphism in human populations ( 4 – 6 ). iNKT cells are thus…
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