At present, it is not clear whether xenogeneic MHC molecules are recognized by T cells directly or indirectly through self-MHC-restricted presentation in a transplantation setting.
Department of Nephrology & Transplantation, King's College, Guy's, King's and St. Thomas' Medical School, Guy's Hospital, London SE1 9RT, UK. stipo.jurcevic@kcl.ac.uk.