Abstract: Objective To express functional BPI_m23-Fcγ1 recombinant bactericidal protein in CHO cells and observe its antibacterial function to drug resistant G^- bacteria usually found in clinical infection.Methods CHO-K1 cells were transfected by pSNAV-signal-syn BPI_m600-Fcγ1₇₀₀ expression vector,positive cell clones which high-expressed BPI_m23-Fcγ1 were selected with Dot blot and cultured in PF-CHO medium to express functional BPI_m23-Fcγ1 recombinant protein.The recombinant bactericidal protein was separated and purified with cation exchange resin(SP sepharose),and detected by Western blot and ELISA.The antibiotic function of BPI_m23-Fcγ1 protein to drug resistant bacteria,such as Klebsiella pneumoniae and E.coli were tested by MIC drug sensitivity test.Results Positive cell clones which high-expressed BPI_m23-Fcγ1 obtained,The expressed quantity of BPI_m23-Fcγ1 protein was about 25⁵0 mg/L.It was proven that this protein was BPI_m23-Fcγ1 recombinant protein by Western blot and ELISA.The protein has the same antibiotic function to Klebsiella pneumoniae and E.coli(drug resistant/sensitive strains).Conclusion Functional BPI_m23-Fcγ1 recombinant protein is obtained in high amount,it can inhibit and kill drug resistant Klebsiella pneumoniae and E.coli effectively at concentration of 0.4 mg/L.

Key words: BPI_m23-Fcγ1 recombinant bactericidal protein, CHO-K1 cell, drug resistant bacteria