Abstract

There have been many postulations about the origin of the plasma cell namely, lymphocytic origin, reticum cell origin and adventia cell origin, etc. Early reports on the plasma cell origin were chiefly on morphologic observations of the resemblance between the plasma cell and the lymphocyte or the intermingled appearance of the two kinds of cells in an inflammatory lesion. The first experimental study on the origin of the plasma cell was performed by Fagrareus (1948) with a conclusion that the reticum cell was the origin of the plasma cell. At the present time, the B-lymphocytic origin of the plasma cell is the most prevailing hypothesis based on various arounds such as in vivo animal experiments, congenital immune-deficiency diseases, and in vitro transformation study of lymphocyte culture. The trends have led many researchers to make an attempt to classify lymphoid tissue tumors into the T-lymphocytes series or the B-lymphocyte ones. According to the theory of the B-lymphocyte origin, the transformation of sensitized B-lymphocytes into plasma cells takes place by meeting an antigen in the peripheral lymphoid tissue such as lymph nodes and spleen. If so, the bone-marrow origin of multiple myeloma and the starting of plasmacytoma in the soft tissue can not be explained reasonably. The confirmation of both defect of plasma cell and lymphocyte in the agammaglobulinemia is also disputable. This brief review was intended to sum up our experimental investigations conducted so far on the origin of plasma cells. The outline is as follows: 1) A whole-body X-ray (400R) irradiation of experimental animalt(rabbits, rats) induced marked regressive changes in the entire lymphoid tissue, causing destruction of mature lymphocytes, proliferation of macrophages within the first few days, and proliferation of plasma cell-series in the next few days. The proliferation of plasma cell series was preceded by an antecedent proliferation of reticular cells and proplasma cells the morphological process of direct transformation of reticular cell into a plasma cell series could be confirmed electronmicroscopically and autoradiographically both in the thymus of rats and in the bursa Fabricius of chickens. 2) A similar erocess of changes due to X-ray irradiation also took place in rats infused with cortisone, DOCA and in adrenalectomized rats. 3) In experiments, where rabbits were inoculated with sensitzed thoracic duct cells or with thoracic duct B-cells combination with antigen into the anterior eyer chambers, a sequential microscopic observation of the smear of the anterior chamber fluid disclosed no transformation lymphocytes into mature plasma cells, 4) In experiments in which both thoracic duct cells and thoracic duct T-cells were inzeeted into the subcutaneous tissue in the back of rabbits, temporal plasmacytopoiesis were induced around the small vessels near the muscle coat or hair follicles, but the injection of UV-irradiated thoracic duct cells could not induce any new building of plasma cells. The plasm-acytopoiesis was supported by in toto newly formed reticular tissue. 5) Newly formed plasma cells in the subcutaneous tissue showed positive IgG fluorescence reaction. 6) The newly formed plasma cells in the follicles of the bursa Fabricius after a whole body X-irradiation (400R) showed also positive IgG fluorescence reaction. The results suggest that plasma cells originate from local reticular cells and those cells are able to produce immunoglobulin. Therefore, it can be concluded that lymphocytes (including T-lymphocytes) have inducing effect in the formation of plasma cells