Pregnancy-induced H-Y antibodies and their transmission to the foetus in rats.

Rats of DA strain produce H-Y antibodies in response to the stimulation by their male foetuses. About 52% of the rats following a single or multiple pregnancy and 45.5% of litters (female offspring) had detectable levels of H-Y antibodies in their blood serum. The presence of H-Y antibodies did not appear to be correlated with the stage of parity or the number of male foetuses the female bore. H-Y antibodies were detected in the serum of a 27 day post-partum female and her 27 day old female offspring but not in any of the male offspring. It is suggested that H-Y antibodies are transmitted to the foetus in utero and through the milk (colostrum). The possible significance of these findings in relation to the ontogenic role of H-Y antigen is discussed.