Relative binding activities and specificity of anti-IN–scFvs. (a) The relative binding of anti-IN–scFvs to 200 ng of HIV-1 IN, PR, and BSA was evaluated by ELISA. The anti-LANA1 scFv (BM10) was used as a control antibody. Optical density at 405 nm was measured. Shown are average values of three independent experiments. (b) The indicated amounts of purified HIV-1 IN protein were separated by 15% SDS-PAGE and transferred to nitrocellulose membranes. For immunodetection, purified anti-IN–scFv clones 7, 104, 135, 142, and 144 were used (20 μg/mL). HRP-conjugated anti-HA mAb was used as a secondary antibody. HIV-1 PR at 800 nM was used to test anti-IN specificity and anti-LANA1 scFv (BM10) was used as a control antibody. Molecular weight is indicated in kDa.