Regulation of early chicken thymocyte proliferation by transforming growthfactor-beta from thymic stromal cells and thymocytes

We examined expression of TGF-betas in chicken thymic stromal cells and thy mocytes and roles of TGF-betas in thymocyte development within the thymus. Thymic stromal cells expressed TGF-beta 2 and 3 genes but not TGF-beta 4 ge ne. Thymocytes showed expressions of TGF-beta 2, 3 and 4 genes and each TGF -beta gene was expressed more strongly in CD3(-) than CD3(+) thymocytes. Wh en anti-TGF-beta antibody was added with supernatants of stromal cells into thymocyte culture, only proliferative activity of CD3(-) thymocytes was en hanced and the cell in S and G(2)/M compartments of cell cycle increased. T hese results suggest that TGF-beta which is expressed in the thymus may reg ulate the ability of immature thymocytes to progress through the cells cycl e and to differentiate to CD3(+) thymocytes. (C) 2000 Elsevier Science B.V. All rights reserved.