Figure 2.

Surface expression of p75/AIRM1 or CD33 antigens in fresh or cultured CD34⁺ myeloid precursors isolated from cord blood and effect of anti-p75/AIRM1 or anti-CD33 mAb on their in vitro induced proliferation. A highly purified CD34⁺ cell population that did not express either p75/AIRM1 or CD33 antigen (A Left) was cultured with SCF and GM-CSF. The surface expression of p75/AIRM1 or CD33 was analyzed at different culture intervals, as indicated. In B, CD34⁺ populations isolated from different cord blood samples were analyzed for proliferation either in the absence of mAbs or in the presence of mAbs specific for p75/AIRM1, CD33, CD34, or IRp60 molecules. The data indicate the percentage of cell recovery (at day 6) in the indicated culture conditions vs. control culture (containing no mAb). Bars indicate the mean (±SE) of five independent experiments.