ABSTRACT

In mammalian gestation, immunologic acceptance and tolerance are paramount for the successful interaction between the embryo/graft and its maternal host. Embryo signaling overcomes the problem that only half the genome is maternal and the other half is paternal, to the extreme example of cross-species pregnancy. The culture media in which embryos were grown in vitro have been shown to have immune regulatory properties. The embryo is then protected from the maternal immune system. However, the mother becomes aware of the embryo a very short time after fertilization due to signaling. The effect on embryo adhesion genes was shown by increased Down syndrome cell adhesion molecules such as SORBS2 and SORBS1 expression. The embryo has the necessary elements to progress through birth and development to adulthood. The environment in which the embryo develops has a great impact on future postnatal life.