Maturation of adult peripheral blood CD38+CD4+ T cells demonstrated by cytokine production in response to a superantigen, TSST-1

This study looks at immunoincompetent CD4+ T cells in adult peripheral blood (APB) using cytokine production in response to a superantigen as a measure of function. We compared the function of APB CD38+CD4+ and CD38−/lowCD4+ T cells to that of cord blood (CB) CD4+ T cells. APB CD4+ T cell blasts produce substantial amounts of IL-2 in response to TSST-1 restimulation, while CB CD4+ T cell blasts produce less. APB CD38+CD4+ T cells produce low levels of IL-4 and IFN-γ in response to TSST-1, even after activation, while APB CD38−/lowCD4+ T cells retain their ability to produce high levels of these cytokines despite high CD38 expression. These results suggest that the developmental stage of APB CD38+CD4+ T cells lies between that of CB CD4+ T cells and APB CD38−/lowCD4+ T cells and that APB CD38+CD45RO−CD4+ T cells gradually cease to express CD38 as they acquire full function. We reconsider CD4+ cell maturation and response to TSST-1 and discuss the implications of T cell maturity on infectious diseases.