Abstract
The mechanisms underlying rejection of grafted neural tissue are still being defined. Mechanisms relevant to genetically engineered cells are of current interest. To date, attention has focused on major histocompatibility complex (MHC) antigens as targets of graft rejection. Yet even when there is no MHC disparity, as when the patient's own cells are genetically altered, there is still a potential for graft rejection, directed against the novel antigens. We illustrate this in a rat model.