Transfer of anaphylactic antibodies from mother to young in the rat.

The transfer of anaphylactic antibodies of classes IgE and IgGa from immunized female rats to babies was examined during primary and secondary immunization by injection, and also in rats infested with Trichinella spiralis. IgE antibodies were never detected in the blood of the babies, although they were sometimes detected in the milk in their stomachs. Similarly, no IgE antibodies were found in the serum of babies from mothers infested with Trichinella spiralis during pregnancy. IgGa antibodies were present in the serum and milk of the mothers following secondary immunization, and were readily absorbed through the intestine of the babies.