Fig. 2. CCL19 binds equally to all CCR7 variants. 300-19 pre-B cells stably transfected with wild-type CCR7 or the CCR7 mutants were incubated with monobiotinylated CCL19 (1 µg/ml) for 20 minutes at 4°C. CCR7-bound CCL19-biotin was then detected with streptavidin-FITC and monitored by flow cytometry (upper panel). CCR7 cell surface staining was performed with a FITC-labeled CCR7-specific antibody (lower panel). Dashed lines represent untransfected cells stained with the same antibody. FITC-labeled isotype control staining on transfected cells revealed the same results. Results are representative of two experiments.