Bactericidal Activity Elicited by the Beta C Protein of Group B Streptococci Contrasted with Capsular Polysaccharides

Abstract

While it is well established that the combination of bacterium-specific antibodies and complement may provide bactericidal (BC) activity for gram-negative bacteria (e.g., meningococci) through complement-mediated lysis, gram-positive bacteria, like group B streptococci (GBS), previously appeared to require phagocytic cells in order for complement-mediated killing to occur. However, evidence has now been obtained showing that antibody-dependent, complement-mediated killing has occurred by a mechanism that is not opsonophagocytic (OP); i.e., in the absence of phagocytes.