An efficient fusion protein system for expression of Bacillus anthracis protective antigen as immunogenic and diagnostic antigen

Objective:To produce high quantities of recombinant protective antigen(rPA) for human vaccine and diagnosis.Methods:The PA gene was amplified by PCR with pXO1 plasmid as template. The PCR product was cloned into pMAL-c2X vector using the BamH1 and SalI restriction enzymes.The recombinant plasmid was transformed into Escherichia coli DH5 a strain and then screened for transformation.The expression of protective antigen was analyzed by SDS-PAGE and Western blotting after isopropyl β-D-thiogalactopyranoside(IPTG) induction.Results: The full-length PA gene(2.2 kb) was cloned into pMAL vector system.The recombinant vector was confirmed by restriction enzyme and PCR analysis.The expression of cytoplasmic maltose-binding protein-protective(MBP-P) antigen fusion protein was detected by SDS-PAGE and Western blotting,and obtained a 125 kDa protein band,which was similar to expected size of fusion protein.Conclusions:This expression system can be used in the high production of rPA. After purification and immunization studies,the purified rPA may be used in the development of the human recombinant anthrax vaccine and also in diagnosis of anthrax disease.