Non-major histocompatibility system immunogenetic influences in rat renal allograft survival

H-1-incompatible rat renal allograft survival rates are strongly influenced by the non-major histocompatibility system (MHS) genes. The same H-1 (MHS) incompatibility tested on four different non-MHS backgrounds gave widely differing results ranging from 11 to 60% fractional survival between the best and the poorest (P less than 0.01) at 105 days. These results can best be explained if non-H-1 and intra-MHS amplifiers and/or suppressors are invoked.