Inflammation alters young and old CD8 T cells

Inflammation plays a significant role in lung infection caused by Mycobacterium tuberculosis (M.tb), and both adaptive and innate lymphocytes can affect infection control. How inflammation affects infection is understood in a broad sense, including inflammaging (chronic inflammation) seen in the elderly, but the explicit role that inflammation can play in regulation of lymphocyte function is not known. To fill this knowledge gap, we used an acute lipopolysaccharide (LPS) treatment in young mice and studied lymphocyte responses compared to old mice, focusing on CD8 T cell subsets. LPS treatment decreased the total numbers of T cells in the lungs of LPS mice, while also increasing the number of activated T cells. We demonstrate that lung CD8 T cells from LPS mice became capable of an antigen independent innate-like IFN-gamma secretion, dependent on IL-12p70 stimulation, paralleling innate-like IFN-gamma secretion of lung CD8 T cells from old mice. Overall, this study provides information on how acute inflammation can affect lymphocytes, particularly CD8 T cells, which could potentially affect immune control of various disease states. Overall design: RNA-seq analysis was performed on CD8 T cells isolated from the lungs of LPS treated, young, and old mice (4 replicates/group).