Flow cytometric analyses of GPIbα, GPIX, GPV, and GPIIb-IIIa (CD41) surface expression during MK differentiation of CD34⁺ cells.

(A) Cell surface expression of GPIbα, GPIX, GPV (FL1 channel), and GPIIb-IIIa (FL2 channel) was analyzed on days 0, 4, 7, 10, and 14 of culture. Negative control curves represent labeling with PE- and FITC-conjugated IgG₁ (see “Materials and methods”). (B) Dot-plot analysis of cells doubly labeled for GPIIb-IIIa (PE-CD41) and GPIbα (FITC-ALMA.12). The upper right quadrant indicates the percentage of cells doubly positive for GPIIb-IIIa and GPIbα. (C) Percentages of GPIIb⁺/GPIbα⁺, GPIIb⁺/GPIbα⁻, GPIIb⁻/GPIbα⁺, and GPIIb⁻/GPIbα⁻ cells determined by double labeling as in panel B. Results are the means ± SEM of at least 6 separate cultures (C), or from a single experiment representative of at least 6 cultures (A and B).