Background: In addition to TCR and costimulatory signals, cytokine signals are required for the differentiation of activated CD8 T cells into memory T cells and their survival. Previously, we have shown that IL-12 priming during initial antigenic stimulation significantly enhanced the survival of activated CD8 T cells and increased the memory cell population. In the present study, we analyzed the mechanisms by which IL-12 priming contributes to activation and survival of CD8 T cells.
Methods: We observed dramatically decreased expression of CD43 in activated CD8 T cells by IL-12 priming. We purified CD43(lo) and CD43(hi) cells after IL-12 priming and analyzed the function and survival of each population both in vivo and in vitro.
Results: Compared to CD43(hi) effector cells, CD43(lo) effector CD8 T cells exhibited reduced cytolytic activity and lower granzyme B expression but showed increased survival. CD43(lo) effector CD8 T cells also showed increased in vivo expansion after adoptive transfer and antigen challenge. The enhanced survival of CD43(lo) CD8 T cells was also partly associated with CD62L expression.
Conclusion: We suggest that CD43 expression regulated by IL-12 priming plays an important role in differentiation and survival of CD8 T cells.
Keywords: CD43; CD8 T cell; IL-12; Survival.