ABSTRACT
The survival of transplanted embryos was also shown to be significantly higher when there was a difference in major histocompatibility complex (MHC) antigens between the parents.5 It has since been observed that the litter size and placental weights were higher in mice preimmunized with
allogeneic paternal strain lymphocytes.6 However, in mice, immunization with syngeneic splenocytes prior to syngeneic mating results in perinatal and postnatal mortality and an increased number of malformations among the progeny.7 Additionally, it has been shown that the sera of habitually aborting women who were immunized with paternal leucocytes improved blastocyst development in culture and reversed the embryotoxic effect of sera from non-immunized women with recurrent miscarriages.8
