Reduced Antibody Response in Thymectomized Rabbits

Abstract

DESPITE considerable experimental work, the function of the thymus has not yet been clearly delineated. Although it is an organ rich in lymphoid cells, it differs from other lymphoid organs in its failure to produce significant amounts of antibody after antigenic stimulation^1–3 and in its embryonic origin from the endoderm of the third pharyngeal pouch. The thymus is largest relative to body-weight during the period of immunological deficiency early in life and it becomes progressively smaller after the immune responses are fully developed⁴, a growth pattern which suggests its relation to the development of immunological mechanisms. The occurrence in the same patient of the two rare conditions, namely, benign thymoma and acquired agamma-globulinæmia^5–7, suggested a relationship of the thymus to immunological processes. Thymectomy in adult or even in young rabbits^6,8,9 had no effect on their antibody response, but subtotal thymectomy performed on young guinea pigs caused reduced antibody formation in some of the experimental groups¹⁰.