Screening and activity identification of an anti-idiotype nanobody for Bt Cry1F toxin from the camelid naive antibody phage display library

Anti-idiotypic antibody technology has been widely developed. Here, we prepared the F(ab') 2 fragments of the Cry1F toxin polyclonal antibody as Ab1and screened an anti-idiotype nanobody (VHH) for Bt Cry1F toxin from the camelid naive antibody phage display library. After three cycles of panning, six clones were isolated and subjected to indirect competitive enzyme-linked immunosorbent assay (IC-ELISA) for the detection of the Cry1F toxin. A competition inhibition rate of 47.00% exists between the anti-idiotype nanobody with the highest activity (5B) and Cry1F toxin for F(ab') 2 fragments. The binding abilities between the anti-idiotypic nanobody 5B and brush border membrane vesicles (BBMV) of Ostrinia furnacalis (Guenée) are also good. The anti-idiotypic nanobody 5B expressed through the prokaryotic system has the same activity as in phage form, and mortality compared to controls could reach 23.3% (P