Immunoblot of a 15% SDS–PAGE analysis showing purified sFv proteins using protein A chromatography (lane 1, anti-NIP; lane 2, B1; lane 3, B10; and lane 4, H4). Single-chain Fv was purified from bacterial supernatant and eluted protein was visualized with the mouse mAb 9E10, anti-myc tag,24 followed by rabbit anti-mouse peroxidase. The position of 30 000 MW is indicated on the left.