Engineering of Organic Solvent-Tolerant Antibody to Sulfonamides by CDR Grafting for Analytical Purposes

The use of organic solvents to extract chemical contaminants for an immunoassay is mostly inevitable. On this occasion, the intolerance of natural antibodies against organic solvent is detrimental to the performance of immunoassays in terms of sensitivity, assay time, accuracy, and precision. Few studies have focused on improving the low tolerance of natural antibodies to organic solvents for analytical purposes. In this study, we engineered the monoclonal antibody (mAb) 4D11 to sulfonamides through CDR grafting by using one proven highly stable humanized antibody (hAb) 4D5 for the first time. The engineered antibody hAb 4D11 showed significantly improved tolerance abilities to acetonitrile (2% to 20%) and methanol (10% to 20%), and retained the highly affinity and class-specificity to sulfonamides. This study provided a general strategy to improve antibody tolerance to organic solvents and was greatly beneficial to the robust development of immunoassays.