Treatment with Recombinant Interleukin-15 (IL-15) Increases the Number of T Cells and Natural Killer (NK) Cells and Levels of Interferon-γ (IFN-γ) in a Rat Model of Sepsis

BACKGROUND: This study aimed to investigate the effects of treatment with recombinant interleukin-15 (IL-15) on T cells, natural killer (NK) cells, and interferon-γ (IFN-γ) on the immune response in a rat cecal ligation and perforation model of sepsis. MATERIAL/METHODS: Sprague-Dawley rats (n=120) were divided into four groups (n=30). A rat model of clinical sepsis was created using cecal ligation and perforation, and 109 rats successfully developed sepsis. Rats were then injected intraperitoneally with 0.5, 1.0, and 1.5 μg of recombinant rat IL-15 or saline. Survival was determined, and the numbers of T cells and NK cells, and the expression levels of IL-15 and IFN-γ were detected in the peripheral blood of rats in each group at 24 h and 48 h. RESULTS: The levels of IL-15 and IFN-γ, as well as the numbers of T cells and NK cells, were significantly increased in the IL-15-treated groups compared with the control group at both 24 h and 48 h (P<0.05). Levels of IL-15 and IFN-γ were significantly increased in the IL-15-treated groups at 48 h compared with 24 h in the control group. Levels of IL-15, the numbers of T cells and NK cells, and the levels of IFN-γ in peripheral blood were significantly lower at 48 h when compared with 24 h (P<0.05). CONCLUSIONS: In a rat model of sepsis, treatment with recombinant IL-15 significantly increased T cell and NK cell numbers, and levels of IFN-γ, and prolonged the survival of rats with sepsis.