Abstract

It is generally accepted that the plasma cells are transformed from mature lymphocyte through antigenic stimulation, but the origin of the plasma cell is still of dispute. Many authors in our institute, since 1964, have reported that the plasma cell is derived from the reticular cell, by means of autoradiography and electron microscopy, based on the study of the thymus after whole body irradiation cortisone treatments and adrenalectomy. An attempt was made to observe whether IgG was produced by the proliferated pyroninophilic cells in the thymus following whole body X-irradiation or not, and the proliferating mode of the IgG-producing cells by means of immunofluorescent microscopic observation. Normal Sprague-Dawley rat-serum IgG was purified, and anti-rat serum IgG-rabbit immunoglobulin was prepared. Immunofluorescent microscopic observation was made on the thymus from the rat 12, 36, 48, 72 and 96 hours following whole body X-irradiation. The result was as follows; IgG was appeared to be produced by the proliferated pyronlnophilic cellssin the thymus, and the IgG-producing calls were appeared in colony-formation.