Immunoregulatory properties of the proteins present in human milk.

The immunoregulatory properties of several proteins, isolated from human milk, were investigated. Secretory component and galactothermin exhibited immunoregulatory activities in the in vivo and in vitro assays, generating helper cells, changing the ARFC levels and the resistance of thymocytes to hydrocortisone (HC). In addition, the immunoregulatory action of the P protein and its four fractions was studied. The bulk of the activity was found in the fraction II and III. The results suggest that the postneonatal development of the mammalian immune system is under the surveillance of various immunoregulatory proteins contained in maternal secretory fluids.