Abstract: Total RNA was extracted from the hybridoma cells which was prepared through human serum albumin immunized mice and reverse transcribed to cDNA by specific primers. Antibody fragments of VH and VL were amplified by RT-PCR and spliced with CH and CL genes of humanized Fab to construct a human-mouse chimeric single-chain antibody fragment (scFv). The scFv was cloned into pBY vector and transformed into E. coli BL21-trxB(DE3) cells for expression. Through the optimization of fermentation conditions, the soluble expression yield of scFv reached 1.23 g/L and 2.49 g/L in flask and 5 L fermenter respectively. 

Key words: chimeric antibody, scFv, soluble expression, ELISA, optimization of fermentation conditions