Endothelial cell surface SDF-1 expression regulates specific cell arrest under conditions of shear flow. (A) Flow cytometric analysis of surface SDF-1 and CD31 expression in HUVECs (passage 3) and surface SDF-1 expression in HDMECs prior to or after treatment with the enzymes chondroitinase (Chon), heparinase I (Hep I), or heparinase III (Hep III). Filled histograms indicate background staining; open histograms indicate specific staining. (B) Flow cytometric analysis of surface CXCR-4 expression in the Burkitt cell line BL-41, the KSHV-infected primary effusion lymphoma cell line BC-1, and the erythroleukemia cell line K562. (C) BL-41, BC-1, and K562 cells accumulated on HUVEC monolayers either untreated or overlaid with SDF-1 under conditions of physiologic shear stress (1.5 dyne/cm2 for 5 minutes). The results reflect the mean number (± SEM) of adherent cells from 5 randomly selected fields per condition. Representative experiment of 5 performed is shown. (D) Accumulation of BC-1 and K562 cells on HDMEC monolayers either untreated or overlaid with SDF-1 under conditions of shear flow (1.5 dyne/cm2 for 5 minutes). The results reflect the mean number (± SEM) of adherent cells from 5 randomly selected fields per condition. (E) Effects of BC-1 cell treatment with pertussin toxin (PTX) and effects of HUVEC treatment with either anti–SDF-1 mouse monoclonal neutralizing antibody or control mouse IgG1 on the arrest of BC-1 cells under conditions of shear flow. The results reflect the mean number (± SEM) of adherent cells from 5 randomly selected fields per condition. Representative experiment of 3 performed is shown. (F) BC-1 cell arrest under conditions of shear flow on HUVEC monolayers untreated, loaded with SDF-1, treated with heparinase I (Hep I), or treated with chondroitinase (Chon). The results reflect the mean number (± SEM) of adherent cells from 5 randomly selected fields per condition. Representative experiment of 4 performed is shown.
