Phagocytic capacity of ECs measured by flow cytometry.

Nonapoptotic B-CLL cells were labeled with the fluorophore TAMRA, as described in “Materials and methods.” (A) Dot-plot (FSC/SSC) of ECs and TAMRA-labeled B-CLL cells after 3 days of coculture is shown. Gate R1 was drawn around ECs according to FSC/SSC criteria. Dot plots of FL1 (y-axis)/FL2 (x-axis): (Ai) CD45 expression (FL1) and FL2-autofluorescence of ECs only; (Aii) CD45 and TAMRA (FL2) signals on ECs gated on R1 after 3 days of coculture. (B) Ingestion kinetics of apoptotic cells by ECs after 1, 2, and 3 days of coculture. Values represent means of triplicate samples from one representative experiment. SEM was always less than 5%.