Influence of the intestinal epithelium to the plasma cell differentiation injected into the thymus.

Physiological saline solution of enzyme-isolated small intestinal epithelium of rat embryos was injected into the thymus of adult rats, thus increasing the number of epithelial cells in the parenchyma. The effect of the cellular composition of the thymus parenchyma was studied with special regard to plasma cells. Considering the functional importance of epithelial elements in the lymphoepithelial organs, the intervention rendered the thymus similar to the lymphoid organs of the intestinal tract; Plasma cells failed to appear in the thymus, but their number in the lymph nodes surrounding the thymus was considerably increased. It is supposed that under normal circumstances the thymus contains an inhibitory factor, which would make it possible to induce plasma cell transformation, but would inhibit maturation during the presence of the cells in the thymus.