A highly sensitive method for the detection of cell surface antigens on preimplantation mouse embryos

An enzyme-linked immunosorbent assay (ELISA) was developed to detect H-2 antigens on preimplantation mouse embryos. The presence of these antigens was shown on early blastocysts from the outbred strain CF1. The assay consists of treating the embryos with purified anti-H-2 monoclonal antibodies followed by treatment with rabbit anti-IgG and protein A-beta-galactosidase conjugate. Removal of the zonae pellucidae by pronase did not change the sensitivity of the assay. However, longer treatment of the embryo surface with pronase eliminated the binding of the anti-H-2 antibodies. The embryo ELISA was shown to be more sensitive than an embryo cytotoxicity assay also described in this paper. The ELISA technique should be useful for future studies of the surface of early embryos.