SIGNR1-negative red pulp macrophages protect against acute streptococcal sepsis after Leishmania donovani-induced loss of marginal zone macrophages

Abstract

Marginal zone macrophages in the murine spleen play an important role in the capture of blood-borne pathogens and are viewed as an essential component of host defense against the development of pneumococcal sepsis. However, we and others have previously described the loss of marginal zone macrophages associated with the splenomegaly that follows a variety of viral and protozoal infections; this finding raises the question of whether these infected mice would become more susceptible to secondary pneumococcal infection. Contrary to expectations, we found that mice lacking marginal zone macrophages resulting from Leishmania donovani infection have increased resistance to Streptococcus pneumonia..