Rejection of cultured thyroid allografts by the transfer of sensitized LYT 2+ T cells.

Cultured BALB/c (H-2d) thyroid allografts, which are accepted permanently in fully immunocompetent allogeneic CBA/H (H-2k) recipients, are rejected following the transfer of immune spleen cells generated by immunization of recipient-strain mice with P815 (H-2d) which, like the cultured thyroid, expresses only class I major histocompatibility (MHC) antigens. Depletion of Lyt 2+ T cells from the transferred population abolished the capacity of immune spleen cells to trigger rejection, whereas depletion of L3T4+ T cells was without effect. Transfer of in-vitro-activated H-2d specific Lyt 2+ T cells also triggered rejection of cultured thyroid allografts. The results are consistent with previous studies showing that sensitized Lyt 2+ T cells are required for rejection of cultured pancreatic islet allografts, which also express only class I MHC antigens. These results are in accord with the notion that Lyt 2+ T cells are activated by and are active against class I MHC antigens.