Production and determination of specificity of monoclonal IgG anti-mouse-blastocyst antibodies

Five monoclonal anti-mouse-blastocyst IgG antibodies were raised by intrasplenic immunization of three mice with adhesive-stage mouse blastocysts. Each mouse received a total of 60-70 blastocysts which were either nitrocellulose-immobilized or living but irradiated. Tests for pre-implantation stage-specificity showed that the antibodies differed in specificity. None were specific for surface epitopes. One antibody recognized epitopes only on blastocysts. Other antibodies were able to discriminate between unfertilized and fertilized oocytes, uncompacted and compacted morulae, or delayed and adhesive blastocysts. By applying reduced SDS-PAGE and Western blotting to blastocysts the blastocyst-specific antibody was seen to be bound to a peptide of M(r) 34.