DEFENSE FACTORS IN HUMAN-MILK

The newborn infant is more susceptible to infections than older childr en or adults. This is because all three lines of defense against micro bial invasion, ie, barrier functions, innate immunity, and specific im munity, are to a greater or lesser extent immature at birth. Nature's response to the immaturity of the infant's immune system is to provide ready-made defense factors from the mother. This is achieved first by the transplacental passage of IgG antibodies, and later via the breas t milk. Breastfeeding has been shown to decrease morbidity in gastroen teritis, septicemia, otitis media, urinary tract infection, and necrot izing enterocolitis. Breast milk contains a wide variety of defense fa ctors, ie, immunoglobulins, leukocytes, hormones, cytokines, and compl ex oligosaccharides in free form or bound to macromolecules. These fac tors are reviewed and their potential protective effects in the abovem entioned clinical states are discussed.