Sarkar, Sanghita

Abstract We have previously demonstrated that inbred B10.T(6R) mice are resistant to Yesinia pestis (KIM5 strain) and resistance decreases with age. It has been shown that Y. pestis is cleared by neutrophil engulfment. We evaluate here the potential contribution of IL-1β, a proinflammatory cytokine important for neutrophil recruitment and activation. IL-1β levels were measured from spleens and sera collected 60 and 72 hour post infection from young (resistant) and middle-aged (susceptible) B10.T(6R) mice and control (susceptible) C57BL/6. Splenic IL-1β production was statistically higher in young B10.T(6R), compared with both middle-aged B10.T(6R) and C57BL/6 mice. Serum IL-1β levels were also moderately higher in young B10.T(6R) mice when compared to middle aged B10.T(6R) and C57BL/6 mice. IL-1β produced by Y. pestis-infected peritoneal-derived macrophages taken from uninfected young and middle-aged B10.T(6R) mice and C57BL/6 mice was measured at 2,4,8 and 24 hour. IL-1β levels were significantly elevated in peritoneal macrophages infected in vitro from young B10.T(6R) mice compared to decreased levels in both middle-aged B10.T(6R) and C57BL/6 derived peritoneal macrophages. These studies suggest a direct correlation between elevated IL-1β levels and resistance to Y. pestis infection observed in young B10.T(6R) mice.