Graft rejection across transgene-encoded MHC class II molecules.

To investigate the capacity of class II gene products of the major histocompatibility complex to serve as targets for allograft rejection, we have used lines of transgenic mice which express such genes on a common genetic background. These lines allow us to test the function of single class II molecules, or of single chains of the class II heterodimers, in graft rejection or tolerance induction. Our data show that some class II molecules (A alpha, A beta) can induce very efficient rejection, while others are relatively inert (E), and that tolerance induction requires matching for both chains of the target class II heterodimers.