Prolonged survival of class II transactivator-deficient cardiac allografts.

Background: Major histocompatibility complex (MHC) antigenic complexes trigger allogeneic T-cell responses and allograft rejection. MHC class II and related antigen processing genes, such as invariant chain (Ii) and H2-DM accessory molecules, are controlled by the master transcriptional regulator, class II transactivator (CIITA). CIITA also up-regulates MHC class I gene expression in vitro.