WT1 RNA and protein expression in leukemic cell lines and in CD34⁺ and CD34⁻ cell populations freshly isolated from patients with leukemia and normal donors.

(A) RT-PCR to measure WT1 RNA in leukemic cell lines and in the B-lymphoid cell line C1R-A2. The same cell lines were used as CTL targets in Figure 1C. The amplified WT1 product is 482 bp long. The RNA of the housekeeping ABL gene was amplified to indicate the amount of RNA in each sample. The ABL product is 385 bp long. (B) RT-PCR to measure WT1 RNA expression in purified CD34⁺ and CD34⁻ cell populations from 4 patients with CML and 3 normal donors. The leukemic cell line BV173 served as a positive control for WT1 expression. Similar results were obtained with samples from 6 additional patients with CML. (C) Western blotting to measure WT1 protein expression in leukemia cell lines and in purified CD34⁺ and CD34⁻ cell populations from 2 patients with CML and 2 normal donors. The expression of the housekeeping actin protein was used as an indicator to control for the amount of protein in each sample. The WT1 protein measures approximately 54 kd and the actin protein approximately 42 kd.