[Gene cloning and expression of human bactericidal/permeability-increasing protein]

The gene of human bactericidal/permeability-increasing protein (BPI) was cloned from peripheral blood lymphocytes of a normal Chinese individual. The result of sequencing showed the gene is 1452 bp encoding a 27-residue signal peptide and a 456-residue matured protein, and it has six nucleotide variations compared with the sequence reported which results in 4 different amino acids. In order to get recombinant BPI, the gene was cloned into an expressing plasmid and expressed in CHO cells. The recombinant protein was purified using cation-exchange chromatography and its bioactivity was proved with bactericidal assays.