Suppression of autoantibodies is specific for the foreign antigens inducing the autoimmunity.

Mice injected with rat erythrocytes produce erythrocyte autoantibodies and suppressor cells that specifically inhibit the autoimmune response without inhibiting the net production of antibodies against rat erythrocytes. Here it is shown that the suppressor cells bind preferentially to monolayers of rat erythrocytes rather than to erythrocytes from mice or sheep. Suppressor populations depleted of B cells, and cells that adhered to monolayers of rat erythrocytes, lost the ability to suppress the production of autoantibodies in normal mice injected with rat erythrocytes. In contrast, suppressor populations depleted of B cells and cells that adhered to sheep erythrocytes or mouse erythrocytes retained suppressor activity. From these results it is suggested that the regulation of autoantibody production by the suppressor cells in this model may be part of a normal system by which antibody responses to foreign antigens are regulated, and not a unique homeostatic mechanism by which harmful autoimmune responses are eliminated.