Abstract
Skin graft rejection was previously shown to be mediated by sensitized lymphocytes bearing the Thy-1+, Ly-1+2-3- cell surface phenotype and these cells were further characterized using antisera to the Ly-5, 6, and 7 specificities. By using an adoptive transfer system in which ATXBM mice (CBA/H) received sensitized cells treated with antiserum and complement, it was shown that the cells mediating skin graft rejection were of the Ly-5+6-7+ phenotype. Other studies have demonstrated that cytotoxic T cells are Ly-5+6+7-, whereas helper T cells are Ly-5+6-7+, so that the T cells-mediating graft rejection is again clearly distinguished from the cytotoxic T. cell. At this time, however, it is not possible to separate the T cells mediating helper T cell functions, delayed-type hypersensitivity (DTH), and allograft rejections.