Cell surface expression of hSCF in thymocytes derived from transgenic mice. (A) Thymocytes from wt control mice were stained with either isotype control (Pharmingen) or mouse antihuman SCF MoAb (Genzyme, Cambridge, MA) and an FITC-conjugated goat F(ab′)2 antimouse IgG secondary. (B) Thymocytes from hSCF²²⁰ mice were stained with either isotype control or mouse antihuman SCF MoAb and an FITC-conjugated goat F(ab′)2 antimouse IgG secondary.