Different expression systems resulted in varied binding properties of anti-paclitaxel single-chain variable fragment antibody clone 1C2.

The binding properties of recombinant antibody fragments, such as affinity and specificity, determine their usefulness for therapeutic and analytical applications. Anti-paclitaxel single-chain variable fragment clone 1C2 (anti-PT scFv1C2) was expressed using Escherichia coli cell and Bombyx mori larvae expression systems. The binding characteristics of the scFvs were evaluated using indirect competitive ELISA. The linear range of binding between anti-PT scFv1C2 and paclitaxel was significantly different between the anti-PT scFv1C2s derived from E. coli (1.056-5.700 μg/ml) and B. mori (7.813-1000 ng/ml), which indicated that different expression systems resulted in different sensitivities for paclitaxel determination. In addition, the binding specificity of anti-PT scFv1C2 varied between expression systems. This finding implied that the expression system significantly affects the binding properties of recombinant antibodies, especially antibodies against low-molecular-weight targets.