MAb 3E7 binds weakly to normal cells in citrated whole blood compared with ARH-77 cells in the presence or absence of RTX.

The first 4 bars in each group represent FITC mAb 3E7 binding to blood cells from 2 healthy donors in the absence of ARH-77 cells; the fifth (black) bar denotes binding of FITC mAb 3E7 to PKH26-labeled ARH-77 cells added to whole blood. Binding of FITC mAb 3E7 to monocytes and granulocytes was 3000 to 8000 molecules of equivalent soluble fluorochrome (MESF); the isotype control averaged 2000. The slightly elevated binding of mAb 3E7 to basophils in the presence of RTX was not found in 4 other bloods (not shown). A standard gate of APC CD45 vs side scattering was used to identify basophils, granulocytes, monocytes, and lymphocytes. ARH-77 cells were identified based on the PKH26 label.