The effects of binding mouse IgA to dinitrophenylated Salmonella typhimurium on physicochemical properties and interaction with phagocytic cells.

The binding of mouse IgA antibody to DNP-conjugated bacteria enhanced the hydrophobic interaction when measured in dextran-poly(ethyleneglycol) two-phase systems and hydrophobic interaction chromatography. Similarly the interaction with polymorphonuclear leukocytes in vitro increased. In contrast, the rate of clearance of IgA-reacted bacteria from the blood stream of mice, after intravenous injection, was reduced under the conditions tested. Our data showed, with respect to increased hydrophobic interaction and opsonization, that binding of IgA antibody to bacteria produced less pronounced effects than those of IgG antibody binding. In contrast, secretory IgA antibody binding has been shown to reduce hydrophobic interaction and phagocytosis. Thus, serum IgA antibody has properties intermediate to IgG and SIgA with respect to hydrophobicity and opsonization.