CD45 Antibodies. A monoclonal antib

CD45 Antibodies. A monoclonal antibody to the CD45 antigen is used in combination with CD34 to provide an additional parameter for identification of the CD34+ cell population. Primitive blast cells characteristically express CD45 at low to intermediate levels. This feature, in combination with relatively low side-angle light scatter properties, is useful in positively identifying normal and leukemic blast cells (31-33), and a variation in this blast cell gating approach (33) was instrumental in our basic methodology to identify true CD34+ cells (25). The CD45 staining pattern is also useful as an indicator of the effectiveness of the red cell lysis step, as well as distinguishing white blood cells (WBC) from contaminating events, such as platelets, platelet aggregates, and other debris that can bind low levels of PE-conjugated CD34 antibodies.