Neutral glycolipid antigens as developmental markers of mouse teratocarcinoma and early embryos: an immunologic and chemical analysis.

Purified rabbit antibodies to neutral glycolipids were analyzed for their binding to mouse embryonal carcinoma cells (ECC) and preimplantation mouse embryos. Antibodies to globotetraosylceramide first bind to 2 to 4-cell embryos and reach a peak of staining intensity with morulae, whereas anti-Forssman antibodies first bind to late morulae and then, most intensely, to early blastocysts. We compared the binding of a monoclonal anti-Forssman antibody with that of rabbit anti-Forssman antibodies and show that although they react similarly with ECC, they do not do so with morulae: The monoclonal antibody stained weakly and unevenly, whereas the rabbit antiserum produced a uniformly bright immunofluorescent staining. Chemical analyses revealed that globotetraosylceramide is the most abundant glycolipid of F9 ECC and that there is poor correlation between the concentration of individual glycolipids in these cells and their reactivity with antibodies to glycolipid molecules. Interestingly, the 2 Forssman antibody-reactive glycolipids of F9 ECC differ in their mobility on TLC plates from the classical Forssman antigen extracted from sheep red blood cells. This illustrates the potential problems in extrapolating from the coincident binding properties of an anti-glycolipid antibody to the chemical structure or abundance of an antigen in different cell types.