Effect of IL-6 on antigen-specific CD8+ T cell activation in vitro

Interleukin 6 (IL-6) is a pleiotropic cytokine with diverse roles in homeostasis, inflammation, and cancer. Here we performed transcriptional profiling of OT-I CD8+ T cells activated in the presence or absence of IL-6. In this study, splenocytes from wild type C57BL/6J mice were incubated with SIINFEKL peptide for two days to activate OT-I CD8+ T cells. SIINFEKL was then withdrawn, T cells were rested in medium with IL-2 for three days, and CD8+ T cells were restimulated with anti-CD3 + anti-CD28 antibodies and purified by FACS for RNA sequencing analysis on day 7. Throughout this culture period, some cells were treated with anti-IL6R antibody (clone MR16-1, 5 ug/ml), isotype control antibody (5 ug/ml), recombinant IL-6 (10 ng/ml), or recombinant hyper-IL-6 (IL-6 linked to IL6R; 20 ng/ml). Experimental conditions were run in triplicate, for a total of 15 samples. Conclusion: Neutralization of endogenous IL-6 signaling (with anti-IL6R antibody) enhances effector differentiation of CD8+ T cells, while addition of exogenous IL-6 or hyper-IL-6 suppresses effector differentiation. Activation of TCR-transgenic T cells in vitro with cognate peptide in the presence or absence of IL-6 signaling inhibitors or recombinant IL-6.