Detection of soluble scFv. A Soluble scFv-M6-1B9 was separated on 12% SDS-PAGE, electroblotted onto PVDF membrane, and probed with peroxidase-conjugated mAb anti-HA (lane 1) and anti-His mAb (lane 2). The immunoreactive bands were visualized by ECL substrate detection system. The molecular weight is indicated. B CD147-BCCP (open columns) or SVV-BCCP (black columns) was captured on the avidin-coated wells. Soluble scFv-M6-1B9 was subsequently added and the bound scFv was detected by peroxidase-conjugated mAb anti-HA. C CD147-BCCP (lane 1) or SVV-BCCP (lane 2) proteins were separated on 12% SDS-PAGE, electroblotted onto a PVDF membrane, and then probed with soluble scFv-M6-1B9. The scFv was detected using peroxidase-conjugated mAb anti-HA. The positions of molecular mass markers are shown on the left. D CD147 on U937 cells was stained with soluble scFv-M6-1B9 and then probed by mouse anti-HA-biotin. Subsequently, FITC-conjugated sheep anti-mouse immunoglobulins antibody was added. Monoclonal antibody M6-1B9 was used as a control system for detecting CD147 on U937 cells. The immunofluorescence on cells stained with soluble scFv-M6-1B9 (bold line) or mAb M6-1B9 (thin line) is shown. The dashed line represents background fluorescence of negative control mAb. The y axis represents the number of events on a linear scale; the x axis shows the fluorescence intensity on a logarithmic scale.