Generation of GSTP1-transfected Raji cell clones. Raji cells were transfected with a PcDNA3.1 plasmid with or without an inserted GSTP1 cDNA sequence. Two clones expressing GSTP1 (RG19 and RG20) and 2 without (RV5 and RV7) were selected by Western blot analysis (A) and activity assays (B), as described in “Materials and methods.”