Function of the lipopolysaccharide-binding protein of Periplaneta americana as an opsonin.

Previously, we reported the purification of an LPS-binding protein from the hemolymph of the American cockroach that was specific for E. coli LPS. In this study we found that this protein participated in the clearance of E. coli cells injected into the abdominal cavity of the cockroach, and that hemocytes ingested E. coli cells treated with this LPS-binding protein in vitro. These findings suggest that this LPS-binding protein acts as an opsonin.