Overexpression of SOCS-1 abrogates T-cell differentiation from hematopoietic progenitors.

Fetal liver–derived hematopoietic precursors were infected with the indicated retrovirus constructs and introduced into dGuo-treated FTOC. (A) Single-cell suspensions were obtained from fetal thymic lobes at day 6 or 14 of culture and analyzed for surface expression of CD4 and CD8 or of CD25 and CD117; percentages of cells in each quadrant are shown. The analysis was confined to infected donor cells by gating on GFP expression, as indicated by the rectangular gate in the GFP versus forward light scatter (FSC) dot plots. (B) Single-cell suspensions were obtained from fetal thymic lobes at day 4 of culture and analyzed for the presence of GFP-expressing cells. As control in each set of experiments, fetal thymic lobes receiving no donor cells were also analyzed.