Coexpression of 97A6 antigen and defined CD antigens on CD34⁺ and CD34⁻ BM cells. BM cells were stained with anti-CD34-PerCP, 97A6-PE, and FITC-conjugated antibodies with the indicated specificities. When antibodies with specificities for CD81 (IgG2a), CD164 (IgG3), and CD17 (IgM) were used, the cells were labeled with the indicated antibodies and stained after washing with F(ab′)2 fragments of FITC-conjugated isotype-specific secondary reagents. Expression on CD34⁻ cells (A) and CD34⁺cells (B) was analyzed after gating on the corresponding populations. 250,000 cells of each sample were analyzed on a FACSCalibur flow cytometer.