THE ROLE OF THE MAJOR HISTOCOMPATIBILITY COMPLEX IN BOVINE EMBRYO-TRANSFER

An intact maternal immune system is not essential for successful repro duction but there is good evidence indicating that it plays an importa nt role during pregnancy. The most prominent candidates for maternal i mmune recognition are the Major Histocompatibility Complex (MHC) antig ens. We have investigated the role of embryo-recipient MHC-compatibili ty in vivo by studying pregnancies after transfer of embryos into 100% compatible or 100% incompatible heifers. Our results showed that MHC antigens are selectively recognized by the immune system of the recipi ent and suggest that they can influence the outcome of pregnancy. If t hese results can be confirmed in larger scale studies, new strategies to improve ET pregnancy rates could be applied. (C) 1996 by Elsevier S cience Inc.