Non-human transgenic mammals carrying transferred genes comprising a regulator gene acting on cells at a site where extra-acute rejection arises and a human N-acetylglucosamine transferase III (GnT-III) gene optionally together with a human complement controlling factor gene. These transgenic mammals show a decrease in a-Gal antigen in cells at the site where extra-acute rejection arises optionally together with the expression of the human complement-controlling factor. Thus, these mammals are highly effective in inhibiting extra-acute rejection which causes troubles in discordant heterotransplantation. Namely, transgenic mammals appropriately usable in organ transplantation are provided.
