The development and proliferation of the trophoblast from ectopic mouse embryo allografts of increasing gestational age

Abstract

The development and proliferation of trophoblast from ectopic mouse embryo allografts and isografts of increasing gestational age in nonimmune and specifically preimmunized hosts was studied. Specific preimmunization of recipients significantly inhibited hemorrhagic nodule development from 3-3 1/2 and 4-4 1/1 day post coitum homozygous blastocysts and from 5-5 1/2 day homozygous egg cylinders. Preimmunization had no effect on the percentage of hemorrhagic nodules which developed from 6-6 1/2 day homozygous egg cylinders. Hemorrhagic nodule development was significantly increased for F1 hybrid allografts compared to homozygous allografts to preimmunized recipients. Coincident with the immune inhibition of hemorrhagic nodule formation was the microscopic finding that in some cases trophoblast cells developed without subsequent proliferation in preimmunized hosts.