RT-PCR. RT-PCR of ZAP70 (top) and GAPDH (bottom). (A) Jurkat cell line; (B) Raji cell line; (C-E) CD19⁺ cells from the peripheral blood of 3 healthy donors; (F) primary T-ALL leukemic cells; (G-I) 3 E2A/PBX1⁺ leukemic cells; (J-L) 3 ALL1/AF4⁺ leukemic cells; and (W) negative control.