IL-15 Improves Aging-Induced Persistent T Cell Exhaustion in Mouse Models of Repeated Sepsis

Aging is a grave problem in sepsis, and T cell exhaustion is the main cause of sepsis-induced immunosuppression. Sepsis- and aging-induced T cell exhaustion is related to secondary infection with a poor long-term outcome in the elderly. However, the trend, impact, and mechanism of T cell exhaustion are still unclear. Interleukin (IL)-15 improves survival rate of septic mice via its antiapoptotic effect on T cells; however, it is still unclear how IL-15 reverses prolonged T cell exhaustion in aged septic mice. The purpose of this study was to clarify the trend of sepsis-induced T cell exhaustion and whether IL-15 prevents aging-induced persistent T cell exhaustion in septic mice. Preserved cecal slurry was injected intraperitoneally into young (6-week-old) and aged mice (18–24-month-old) 4 times, to induce clinically relevant repeated sepsis. IL-15 (1.5 μg) or phosphate-buffered saline was injected subcutaneously 3 times, body weight was serially measured, and peripheral blood cells from their cheek were serially collected for 50 days. Sepsis-induced T cell exhaustion was significantly severe in aged mice than in young mice and was accompanied with decreased naive CD4+ and CD8+ T cells (P 
Source: Shock - Category: Emergency Medicine Tags: Basic Science Aspects Source Type: research