Dietary antigens, immune tolerance and atherosclerosis

To test the hypothesis that a systemic immune response to dietary protein can influence the development of experimental arterial disease rabbits were given diets containing 20% soya protein and 20% fat for 11 months. The substantial levels of circulating antisoya antibody were positively correlated with the macroscopic extent of aortic atheroma. In some arterial changes reminiscent of giant cell arteritis were seen. In subsequent similar experiments the breeding stock had been exposed to a soya containing diet, which was also available to their offspring, the experimental animals, in the perinatal period. The lower antibody titres, and much reduced atheroma in this experiment suggested that the animals had been tolerated to soya protein. In further experiments rabbits, bred on a soya free diet showed much higher levels of antisoya antibody and a giant cell reaction was again identified. It is concluded that the magnitude of the antibody response to dietary protein is an important, and previously unrecognised, factor in the development of experimental atherosclerosis.