NEUTROPHILS PREVENT EXTRACELLULAR COLONIZATION OF THE LIVER MICROVASCULATURE BY SALMONELLA-TYPHIMURIUM

The early course of hepatic infection with the facultative intracellul ar bacterial pathogen Salmonella typhimurium was examined in control m ice and in mice selectively depleted of neutrophils by treatment with a granulocyte-specific monoclonal antibody. The results show that >200 -fold more salmonellae were recovered in livers of the latter group of mice than in livers of the former group by 24 h of parenterally initi ated infection. Comparative histological examination of the livers fro m both groups of mice indicated that neutrophils participate in early anti-Salmonella defense in the liver in part by aborting infection in permissive hepatocytes and by inhibiting extracellular bacterial colon ization of the hepatic microvasculature. It is shown in addition that systemic salmonellosis was also severely exacerbated in neutropenic mi ce infected intragastrically with the pathogen.