Reactivity of secretory IgA antibodies in breast milk from 107 Japanese mothers to 20 environmental antigens.

The secretory IgA (sIgA) antibody response to 20 environmental antigens, including microorganisms, toxins, food, and inhaled allergens, was evaluated in the breast milk from 107 Japanese mothers 1-10 days after delivery. Specific sIgA antibody responses were detected in most milk samples against almost all of the antigens tested, although there was a wide variation in the specific sIgA antibody profiles of each individual's milk. With regard to twelve bacterial antigens, highly specific sIgA antibody responses were detected against Escherichia coli, Yersinia enterocolitica, and Pseudomonas aeruginosa. With regard to eight nonbacterial antigens, highly specific sIgA antibody responses were detected against rotavirus, cholera, and pertussis toxins. Similar sIgA antibody profiles were obtained when the 107 milk specimens were divided into colostrum (milk 1-5 days after delivery, n = 36) and transitional milk (milk 6-10 days after delivery, n = 71). This study provides information on the possible protective role of human milk sIgA antibodies and will serve as a baseline for future studies. Copyright 2002 S. Karger AG, Basel