DAUDI SUPERNATANT, UNLIKE OTHER H-Y-ANTIGEN SOURCES, EXERTS A SEX-REVERSING EFFECT ON EMBRYONIC CHICK GONAD DIFFERENTIATION

In vitro cultures of intact chick gonads (organ cultures) and reaggreg ation cultures of dispersed gonad cells (roller cultures) were made. G onads or gonad cells from 7-day-old chick embryos, at the stage when s ex-specific differentiation begins, were cultured in the presence of p resumed H-Y antigen-containing supernatants, or co-cultured in the pre sence of H-Y antigen-producing cell lines. The H-Y antigen-producing c ells tested were of human, mouse, bovine and chicken origin. During or gan culture, addition of supernatant of the human lymphoma cell line D audi, or co-culture with Daudi cells, stimulated a clear proliferation of the germinal epithelium in male gonads, indicating feminization. A similar effect was obtained by treatment with estradiol. In reaggrega tion culture, the increase in nuclear size of germ cells was chosen as a parameter for feminization. A significant increase of germ cell nuc lear size was observed in gonads cultured in the presence of Daudi sup ernatant. In both organ cultures and reaggregation cultures, other tes ted H-Y antigen sources and semi-purified H-Y antigen fractions did no t exert significant effects on differentiation of the gonads or on the average area of the germ cell nuclei. These findings suggest that it is not H-Y antigen, but another protein produced by Daudi cells, that might be responsible for the sex-reversing effects.