Immunologic aspects of human colostrum and milk. III. Fate and absorption of cellular and soluble components in the gastrointestinal tract of the newborn.

A group of formula-fed infants were administered a single feed of poliovirus IgA antibody-rich human colostrum 18 to 72 hr after birth. Subsequently, the presence of IgG, IgA, and IgM immunoglobulin and poliovirus antibody activity was determined in serial serum and fecal samples of the neonates. Absorption of IgA immunoglobulin from the colostrum to the circulation was observed in three infants who were fed with colostrum between 18 and 24 hr after birth. Another group of infants of tuberculin-positive mothers who were being breast fed by their own mothers were followed for the development of in vitro correlates of cell-mediated immunity against tuberculin after prolonged breast feeding. Tuberculin-specific proliferative response was observed in the peripheral blood lymphocytes of two neonates after 5 weeks of breast feeding. The responses were undetectable after 12 weeks, although the infants continued to breast feed. No tuberculin reactivity was observed in the cord lymphocytes. These observations suggest uptake of IgA immunoglobulin and components of cellular immunity in the intestine during the immediate neonatal period.