Abstract
Adaptive immune cells are regulated by circadian rhythms (CR) under both steady state conditions and during responses to infection. Cytolytic CD8 (+) T cells display variable responses to infection depending upon the time of day of exposure. However, the neuronal signals that entrain these cyclic behaviors remain unknown. Immune cells express a variety of neurotransmitter receptors including nicotinic, glucocorticoid, and adrenergic receptors. Here, we demonstrate that the β2-adrenergic receptor (ADRB2) regulates the periodic oscillation of select core clock genes, such as Per2 and Bmal1 , and selective loss of the Adrb2 gene dramatically perturbs the normal diurnal oscillation of clock gene expression in CD8 (+) T cells. Consequently, their circadian-regulated anti-viral response is dysregulated, and the diurnal development of CD8 (+) T cells into variegated populations of cytolytic T cell (CTL) effectors is dramatically altered in the absence of ADRB2 signaling. Thus, the Adrb2 directly entrains core clock gene oscillation and regulates CR-dependent T cell responses to virus infection as a function of time-of-day of pathogen exposure. ONE SENTENCE SUMMARY: The β2-adrenergic receptor regulates circadian gene oscillation and downstream daily timing of cytolytic T cell responses to virus infection.