The capsular polysaccharide complex of Bacteroides fragilis induces cytokine production from human and murine phagocytic cells.

To stimulate early-phase immunologic events following Bacteroides fragilis infection in the peritoneal cavity, we examined the cytokine response of several cell types to purified capsular polysaccharide complex (CPC) and lipopolysaccharide (LPS) of this organism. Cytokines were produced from murine resident peritoneal (MRP) cells as well as human peripheral blood leukocytes. MRP cells cocultured with either B. fragilis CPC of LPS in vitro produced tumor necrosis factor alpha and interleukin-1alpha (IL-1alpha). In addition, MRP cells challenged with CPC produced IL-10. Human peripheral blood monocytes and polymorphonuclear leukocytes secreted IL-8 when cultured in the presence of CPC.