A bone marrow-derived stroma cell line, ST2, can support the differentiation of fetal thymocytes from the CD4+ CD8+ double negative to the CD4+ CD8+ double positive differentiation stage in vitro.

A bone marrow-derived stroma cell line, ST2, can support the differentiation of fetal thymocytes from the CD4+ CD8+ double negative to the CD4+ CD8+ double positive differentiation stage in vitro.