Generation of an Insecticidal Human Domain Antibody from a Phage Library Targeting Plutella xylostella Brush-Border Membrane Vesicles

The importance of protein-based materials in agricultural pest control has received increasing attention in recent years. Herein, Plutella xylostella brush-border membrane vesicles (BBMVs) were used as a target to screen for human domain antibodies with insecticidal activity. Three rounds of panning of the phage display library yielded the domain antibody C4D, which competed with the Cry1Ac toxin to bind to P. xylostella BBMVs. Against P. xylostella larvae, the recombinant soluble C4D protein showed an LC50 of 1.57 μg/cm2 (95% fiducial limits: 0.83–2.54). Using pull-down assays and liquid chromatography–tandem mass spectrometry, we identified the C4D binding partner in P. xylostella midgut BBMVs to be a cadherin-like protein. Bio-Layer Interferometry assay revealed that the dissociation constant between soluble C4D and P. xylostella cadherin-like protein was 2.99 × 10−6 M. Thus, the present study explored strategies to generate insecticidal antibodies, and the human domain antibody C4D identified and characterized in this study can serve as a framework for generating novel insecticidal agents.