978 SECRETORY IGA ANTIBODIES IN HUMAN MILK AGAINST CANDIDA ALBICANS

Abstract

Secretory IgA (SIgA) antibodies to Candida albicans have previously been detected in pooled human milk by immunofluorescence, and there is some evidence that these antibodies interfere with the adherence of that organism to human buccal epithelial cells (Arch Oral Biol 27:617, 1982). Little is known regarding the mucosal defense against this fungal agent in early infancy. Because of the occurrence of the fungus in the gastrointestinal tract, and the commonness of candidal infections during pregnancy, we hypothesized that high titers of SIgA antibodies to Candida albicans would be frequently present in human milk and would aid in the infant's mucosal defense against this fungus. Milk specimens, collected 2–4 days post-partum from 10 nursing mothers, were centrifuged to remove cells and examined for Candida-specific SIgA antibodies by a micromodification of an enzymelinked immunosorbent assay, utilizing a protein extract of Candid da albicans as the solid phase and an anti-secretory componenthorseradish peroxidase conjugate as the detector. Pooled human colostrum served as a reference standard (titer 1:25). Eight of the subjects studied displayed titers of secretory IgA antibodies to Candida which were >l:16. The range of titers was <1.1 to 1:460 (mean, 1:86; median, 1:32).High titers of SIgA antibodies to Candida albicans found in the majority of milk specimens examined suggest that these antibodies may defend the mucosa of the breast-fed infant against this common opportunistic agent.