Characterization of immune responses to Yersinia pestis infection: resistant versus susceptible mice(129.29)

Abstract

Abstract We have previously reported that inbred B10.T(6R) mice are resistant to Yersinia pestis infection, compared to susceptible strains, e.g. Swiss Webster mice; the mean LD50's for B10.T(6R) females is 14000 CFU's, compared to Swiss Webster females, at 22 CFU's. Interestingly, B10.T(6R) mice demonstrated a more robust pro-inflammatory response early in infection, and a lesser anti-inflammatory response later on, when compared to susceptible Swiss Webster mice. Significantly higher levels of TNF-alpha were detected in B10.T(6R) on day 1 while TNF-alpha responses were delayed in Swiss Webster mice. Conversely, IL-10 levels were not changed in B10.T(6R) mice while IL-10 levels increased significantly in Swiss Webster mice. Yersinia outer membrane proteins (YOP) are translocated into the host cell's cytoplasm via a type three secretion system. After contact with a eukaryotic cell, YOPs then interact with cellular components to disrupt the host's immune response and induce the production of suppressive cytokines, e.g. IL-10. We postulate that the resistant B10.T(6R) strain of mice are able to overcome initial infection with Y. pestis through higher levels of pro-inflammatory cytokines and decreased levels of immune suppressive cytokines later in infection.