Polymorphonuclear neutrophil chemotaxis induced and inhibited by Bacteroides spp.

A possible virulence factor for Bacteroides subcutaneous abscesses has been found. The effect of Bacteroides culture filtrate and outer membrane on chemotaxis of rabbit peritoneal polymorphonuclear (PMN) neutrophils was assayed in Boyden chambers and via exocytosis of N-acetyl-beta-glucosaminidase. Both Bacteroides culture filtrate and outer membrane elicited some chemotaxis, as measured in the Boyden chamber; however, they had little effect upon exocytosis in cytochalasin B-treated PMN neutrophils. In the presence of serum complement, they completely abolished PMN neutrophil movement in the Boyden chamber assay, yet they gave a definite positive response for the exocytosis assay in the presence of serum complement or activated complement fragment.