CELLULAR EVENTS DURING THE INDUCTION OF EXPERIMENTAL THYROIDITIS IN THE RABBIT

With a modification of the Jerne plaque technique to enumerate plaque-forming cells (PFC) to bovine and rabbit thyroglobulin, the cellular kinetics of the antibody response were followed during two 5-day series of injections of an aqueous preparation of bovine thyroglobulin. The results support the suggestion that thyroiditis in the rabbit is mediated by antibody. The peak PFC appear in the spleen at the end of the second series of injections and are considerably greater for bovine than for rabbit thyroglobulin. PFC also appear in the thyroid gland; however, the numbers of PFC for bovine and rabbit thyroglobulin were similar, and they did not reach a peak until 7 days after the peak PFC in the spleen. There was an excellent correlation between the appearance of PFC in the thyroid gland and the appearance of thyroid lesions. The disappearance of antibody to rabbit thyroglobulin from the serum also correlated with the appearance of lesions. Migration inhibition factor (MIF) activity was not produced at any time throughout the study when rabbit thyroglobulin was added to peritoneal exudates of immunized rabbits containing circulating antibody to rabbit thyroglobulin. MIF activity was observed when bovine thyroglobulin was added to similar cells in the later stages of the study after lesions were present.