Targeting Design of Human Anti-idiotypic Genetically Engineered Antibody for Simulating the Structure and Insecticidal Function of Bt Cry1C Toxin.

The β-type anti-Id (Ab2β) is considered to have potential for simulating the structure and function of the antigen. In this study, a β-type anti-Id (3A7 anti-I-GEAb) of the Cry1C toxin was captured from a GEAb library. Subsequently, a higher activity of mutant (3A7 mutant 8) was obtained from the mutagenesis library based on 3A7 anti-I-GEAb. The LD 50 values of 3A7 anti-I-GEAb and 3A7 mutant 8 reach up to 38.9% and 46.8% of Cry1C toxin for P. xylostella and reach up to 32.9% and 37.4% of Cry1C toxin for H. armigera . Additionally, an IC-ELISA was established based on 3A7 mutant 8 (as the coated "antigen"), with an LOD value of 0.35 ng/mL, exhibiting good accuracy and stability for detecting Cry1C toxin in spiked samples. The present β-type anti-I-GEAb not only exhibits insecticidal activity similar to Cry1C toxin, offering potential for environmentally friendly pest management, but it can also replace the Cry1C toxin structure to establish a highly sensitive and specific IC-ELISA for monitoring Cry1C toxin.