Phenotypic characteristics of cells involved in induced suppression to murine experimental autoimmune thyroiditis

Suppression of induced experimental autoimmune thyroiditis can be consistently transferred with spleen cells to syngeneic recipients, provided they are first treated with 200 rads irradiation. Treatment with anti-Thy-1 in vivo immediately prior to transfer abrogates the suppression, while depleting B cells has no effect. The in situ induced tolerance can be prevented by treatment with monoclonal antibodies to the Ly-1 or L3T4 molecules either prior to or post tolerization. Anti-Ly-2 treatment has no effect. In the transfer, again treatment of donors with anti-L3T4 prior to transfer prevents the demonstration of suppression in the recipients, while anti-Ly-2 does not affect suppression. These data suggest that the suppression is being mediated either by a CD4+ T suppressor cell or a CD4+ suppressor inducer cell. Preliminary experiments do not support the possibility of a CD8+ suppressor cell being activated in the recipient.