Effect of diet on adjuvant-induced disease and mitogenic responses of Fisher rats.

Fisher rats from a inbred colony, when fed on a salt-free high-protein diet, developed only a mild arthritis after adjuvant injection. Their spleen cells failed to respond in vitro to concanavalin A (a T-cell mitogen), although they possessed a B-cell function of plaque formation to sheep red blood cells. When a full salt supplement was included in the diet, or magnesium or copper or zinc was included in the drinking water, adjuvant-induced arthritis was severe and the response to the T-cell mitogen was restored. The above results suggest that these trace elements may stabilize or activate certain cell populations needed for some immune responses in rats.