Functional screening and expression cloning of Cdc42 as mediator of immunoresistance. (A) Schematic diagram of the library expression and screening strategies. (B) PCR amplification (left panel; first lane: DNA marker) and sequence (right panel) of the vector-encoded cDNA of clone A4. The vector-encoded EcoRI restriction site is underlined; the Cdc42 open reading frame is shaded. (C) The 5-hour ⁵¹Cr release assay of cA2K^b MEFs (□ indicates parental MEFs; ■, clone A4) coincubated with allo-A2 CTLs. Mean values plus or minus SD of a representative experiment are shown.