Suppression of allosensitization in vitro by cells from tolerant rats.

Lymph node cells from AVN rats tolerant to Lew antigens after neonatal induction of tolerance, which did not react in the mixed lymphocyte culture and cytotoxicity assays, were tested for the presence of suppressor cells. Sensitization of lymphocytes from normal rats was inhibited by the addition of lymph node cells from these tolerant rats. The mixed lymphocyte culture reaction of lymph node cells from normal AVN rats with the irradiated Lew cells was inhibited when lymphocytes from tolerant rats were added. In contrast, the cytotoxicity of immune lymphocytes was not inhibited by the addition of lymph node cells from tolerant rats. Neither did a 24-h or 48-h co-cultivation of immune lymph node cells with lymphocytes from tolerant AVN rats suppress the cytotoxicity.