Autoreactive T cells in mercury-induced autoimmunity. Ability to induce the autoimmune disease.

It has been previously shown that autoreactive T cells appear during mercury-induced autoimmunity in Brown-Norway (BN) rats. In the present work, it is shown that: 1) T cells and T helper cells from HgCl2-injected BN rats are able to actively transfer autoimmunity in normal BN rats; the disease transferred is exacerbated when recipients are treated with the antisuppressor/cytotoxic T cell monoclonal antibody (OX8); 2) normal T cells preincubated with HgCl2 are also able to transfer the disease in OX8-treated but not in T cell-depleted rats; and 3) T cells from HgCl2-injected BN rats also transferred the disease in both normal and T cell depleted rats. It is concluded that: 1) autoreactive T cells, and presumably anti-Ia T cells are involved in the pathogenesis of mercury-induced autoimmunity; 2) these autoreactive T cells induce suppressor/cytotoxic T cells to proliferate in normal syngeneic recipients; the fact that this T cell subset did not proliferate in HgCl2-injected BN rats suggests that HgCl2 also affects T suppressor cells; and 3) mercury-induced autoimmunity could result from the additive effect of the emergence of autoreactive T cells and of a defect at the T suppressor level.