REDUCTION OF PHAGOCYTOSIS, SURFACE HYDROPHOBICITY AND CHARGE OF SALMONELLA-TYPHIMURIUM 395-MR10 BY REACTION WITH SECRETORY IGA (SIGA)

Abstract

Binding of human colostral secretory Ig[immunoglobulin]A (SIgA) to S. typhimurium 395 MR10 decreased the liability to hydrophobic interaction of the bacteria, as analyzed by hydrophobic interaction chromatography on Octyl-Sepharose and partition in an aqueous polymer 2 phase system consisting of dextran, poly(ethyleneglycol) (PEG) and poly-(ethyleneglycol)-palmitate (P-PEG). SIgA reduced the negative charge of the bacteria. Treatment of the bacteria with centrifuged but not fractionated colostrum added positive charge to the bacteria which was removed by treatment with pepsin. Colostral SIgA reduced the in vitro phagocytosis of S. typhimurium MR10 by polymorphonuclear leukocytes. The adhesion of the bacteria to cellulose membrane filters in the absence of phagocytes was reduced after the interaction with SIgA. The binding of SIgA to bacterial surfaces apparently has hydrophilic and anti-adhesive effects, which may serve to exclude antigen from mucosal surfaces.