Reconstruction,expression and characterization of dsFv V_L of human antibody to N terminal fragment of human lipopolysaccharide binding protein / 第三军医大学学报

ABSTRACT

Objective To introduce the mutated gene coding cysteine into the gene of dsFv VL of human antibody to N terminal fragment of lipopolysaccharide binding protein(LBP)and to express,purify the mutated dsFv VL in bacterium.Methods We reconstructed and sequenced the mutated gene of VL of human mAb Fab to LBP by Mega-primer PCR based on point mutagenesis method.Some codes of FWR1 of VL had been replaced by TGT in order to code cysteine.The DNA sequence of reconstructed VL was inserted into vector pET-28a(+),then VL was expressed by E.coli.BL21 star(DE3)and was purified by chromatography.Finally the activity of VL to bind NH-LBP was determined by ELISA.Results The results showed that the cysteine was introduced into the position 21 amino acid of VL to replace the threonine.The gene of VL was about 650 bp and relative molecular weight of VL was 28?103.VL could bind NH-LBP directly.Conclusion These have laid a foundation for producing the dsFv against NH-LBP.