Maternal Fetal Transmission of Human Viruses and their Influence on TumorigenesisThe human foetus is separated from the maternal blood by the syncytiotrophoblast induced by endogeneous human retrovirus encoded proteins. This barrier is a highly developed one, which suppors apical basolateral transport of maternal idiotype and anti idiotype IgG, IgG virus complexes. The selective maternal fetal transport of epitope and paratope bearing entities can influence the developping fetal immune system during pregnancy. The bidirectional