Opsonizing and bactericidal activity of antibodies against common antigen of Enterobacteriaceae.

Domingue, Gerald J. (State University of New York at Buffalo, Buffalo, N.Y.), and Erwin Neter. Opsonizing and bactericidal activity of antibodies against common antigen of Enterobacteriaceae. J. Bacteriol. 91:129-133. 1966.-In addition to the well-known O, H, K, and Vi antigens, Enterobacteriaceae produce a common antigen, which was first identified by hemagglutination tests with Escherichia coli O14 antiserum. Studies on the biological significance of this antigen by in vitro phagocytic experiments have revealed that opsonization is markedly enhanced in the presence of the corresponding antibody, rabbit polymorphonuclear leukocytes, and normal rabbit serum. This effect is specific, because Pseudomonas aeruginosa, which is devoid of this antigen, is not opsonized under these conditions, and removal of the antibody by absorption markedly reduces the uptake of enteric bacteria containing the antigen. Opsonization thus represents another method for the study of this antigen-antibody system. Bactericidal tests have revealed that antibodies against this antigen, engendered in rabbits by different strains of enteric bacteria and various procedures, are bactericidal for E. coli O14 but not for other enteric bacteria, possibly due to previously demonstrated differences between the antigen moieties obtained from these microorganisms.