CULTURE OF HUMAN THYMIC EPITHELIAL CELLS AND THEIR SECRETORY PRODUCTS
Zhang He-yun,Zhao Yu-wei,Zhu Jia-zhen,Tang Guo-zhi,and Jin Yi-feng (Department of Biochemistry,Nanjing University Nanjing,China)
A human thymic culture dominated by reticulo-epithelial cells was obtained by re-ducing the calf serum concentration and ad-ding triiodothyronine(T_3) to the RPMI 1640 medium.The thymic epithelial subculture cells keep their normal morphological characters within a duration of 90 days in this modified medium.The proliferating cells formed the re-ticular structure which appeared at the 14 th day.The cytochemical and electron microsco-pic observation indicated that most of the cul-tured cells contain a great deal of secretory granuls,vesicles,tonofibrils and desmosomes showing the characters of epithelial cells. All media collection at different time with 3-4 days interval were mixed.The thy-mosin was partially purified from the secre-tion with a bioassay.The results showed tha the cell products have activities to increase the number of rosette forming cells and decrease the TDT level of thymocytes,these facts in-dicated that the cell products have the activi-ty of thymic hormone. According to the facts of morphology,cytochemistry and bioassays,we incline to consider that it is a thymic reticulo-epithelial cells dominated culture.