A full length of F-SC1-Ig fusion protein recognizes the BCB10 pre-B cell line. Either the F-SC1- or CD44-Ig/pEFBOS plasmid was transfected into 293T cells. (A) Supernatants from each transfected sample were immunoprecipitated with proteinG-Sepharose. Western blot was perfomed by using horseradish peroxidase–conjugated goat antihuman Ig and the ECL chemiluminescence detection system. Samples were evaluated under reducing conditions. (B) BCB10 cells were stained with supernatants from each transfected sample, followed by FITC-goat antihuman IgG (shaded histograms). Hanks' solution with (right) or without (left) 5 mmol/L EDTA was used as washing buffer. Negative control stainings obtained with CD44-Ig are also shown (open histograms).