Humoral and cellular immune response in growing rats fed a 10% gluten diet

The effect of protein malnutrition, induced by a diet containing 10% plant wheat gluten, on the immune response system was studied in growing rats. The rats were fed wheat gluten or casein (control) diets, and were the offspring of mothers fed a commercial stock rat diet, a gluten diet, or a casein diet during pregnancy and lactation. Rats fed dietary wheat gluten showed a depressed humoral immune response to antigenic stimulation with sheep red blood cells, regardless of the mother's diet. Both IgG and IgM antibody titers were depressed by the gluten diet, but the effect on IgG was more pronounced. Total hemolysin titers of gluten-fed rats were 41% that of the casein-fed rats. Hemolysin antibodies resistant to 2-mercaptoethanol appeared in the gluten-fed rats 5 days later than in the control rats, and their titers were 38% that of the controls. The number of spleen plaque-forming cells in the experimental rats at the peak of response was lower and delayed by 1 day. An impairment in the cellular immune response, measured by in vitro stimulation of lymphocytes with concanavalin A, was found in the gluten-fed rats. The amount of [3H]methylthymidine incorporated into newly synthesized DNA of lymphocytes taken from lymph nodes of rats fed gluten was 11% that of the control rats. These findings may suggest that a gluten diet, which induces protein malnutrition, affects thymus-dependent immune responses.