The immune response of the mammary gland and its significance for the neonate.
The immune response of the mammary gland is dominated by local production of secretory IgA antibodies (SIgA). These milk antibodies, amounting to about 0.5-1 g/day throughout lactation, are directed against food proteins and microorganisms often present in the intestine. This is presumably explained by the enteromammaric link: after antigenic exposure in the Peyer's patches of lymphoid cells they home to various exocrine glands, including the mammary gland. Similarly, lymphoid cells from the bronchial mucosa, may contribute to the antibody-producing cell population in the mammary gland. SIgA antibodies against common foods like cow's milk and soy proteins are regularly found in milk if such proteins are part of the mother's diet. It is possible, but unproven, that milk antibodies can decrease the exposure of the infant's intestinal mucosa to foreign food proteins introduced during continued breast-feeding. Milk SIgA antibodies do not prevent intestinal colonization by microorganisms, against which the milk antibodies are directed. The SIgA antibodies are thought to exert protection primarily by preventing contact between the microorganisms and the mucosal membranes. In this manner, human milk blocks attachment of otitis media-causing strains of pneumococci and H. influenzae to retropharyngeal cells, possibly explaining why breast-feeding may prevent otitis media. Milk antibodies have anti-attachment capacity, but there is also low molecular weight material in the milk with this capacity. It probably consists of analogues to the oligosaccharide receptor for pneumococci on the retropharyngeal cells.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D000941:Antigens / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D001424:Bacterial Infections / Q000276:immunology; D001940:Breast / Q000276:immunology*; D002417:Cattle; D022121:Cholera Vaccines / Q000276:immunology; D004768:Enterotoxins / Q000276:immunology; D004926:Escherichia coli / Q000276:immunology; D005260:Female; D005512:Food Hypersensitivity / Q000276:immunology; D006166:Guatemala; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D007112:Immunity, Maternally-Acquired; D007071:Immunoglobulin A, Secretory / Q000096:biosynthesis*; D007074:Immunoglobulin G / Q000096:biosynthesis; D007223:Infant; D007231:Infant, Newborn; D007774:Lactation; D051379:Mice; D008892:Milk / Q000276:immunology; D008894:Milk Proteins / Q000276:immunology; D008895:Milk, Human / Q000276:immunology; D009092:Mucous Membrane / Q000276:immunology; D010033:Otitis Media / Q000276:immunology; D010154:Pakistan; D010581:Peyer's Patches / Q000276:immunology; D011054:Poliovirus Vaccine, Inactivated / Q000276:immunology; D011247:Pregnancy; D013025:Glycine max / Q000276:immunology; D014734:Vibrio cholerae
D000941:Antigens; D000942:Antigens, Bacterial; D022121:Cholera Vaccines; D004768:Enterotoxins; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D008894:Milk Proteins; D011054:Poliovirus Vaccine, Inactivated