Influence of oral lysozyme administration on serum immunoglobulin and intestinal secretory IgA levels in infants.

The influence of lysozyme feeding on the production of serum immunoglobulins and intestinal secretory IgA was studied in full-term and premature infants, from birth up to the age six months. Serum immunoglobulins were not influenced by lysozyme administration. An increase in secretory IgA was found in stool filtrates of full-term lysozyme-fed infants; no secretory IgA was detected in controls. In this way lysozyme feeding partly substituted for passive transfer of secretory IgA from maternal milk.