Rat yolk-sac antigen-2 defined by monoclonal antibodies.

The distribution of the rat yolk-sac antigen-2 (Rat YSA-2) as defined by a monoclonal antibody raised against rat yolk-sac carcinoma cells is described. The antigen is present on rat yolk-sac carcinoma, on parietal yolk-sac endoderm and on the epithelium of fetal and adult gut and of the adult proximal kidney tubules. It is not present on a variety of rat tumors other than yolk-sac carcinomas and not detectable on pre-implantation and post-implantation embryos. Rat YSA-2 differs from YSA-I, other stage-specific embryonic antigens, basement membrane antigens, intestinal and tubular antigens.