Flow cytometric analysis of human hematopoietic cell lineages. Whole blood was stained with fluoresceinated-CD148 as described in Materials and Methods and analyzed on a FACScan flow cytometer. (A) Erythrocytes and platelets were analyzed after selecting cell populations by side scatter and forward size. In parallel, after washing, erythrocytes were lysed by incubating with lysis buffer and the different leukocyte populations were selected on basis of cell scatter and forward size characteristics. Histograms for fluorescence of simultaneously stained lymphocytes, monocytes, and granulocytes have been superimposed. (B) PBL were obtained from normal healthy donors by Ficoll-Hypaque gradient density centrifugation and lymphocyte populations were analyzed by two color fluorescence by using fluoresceinated 143-41 MoAb and comercially available PE-labeled CD3 and CD19 MoAb. The appropiate negative control FITC- and PE-labeled MoAbs were used to establish the marker position. The staining intensity of PE-labeled cells is shown in the vertical axis with 143-41–FITC staining on the horizontal axis.