Development of ELISA based on Bacillus anthracis capsule biosynthesis protein CapA for naturally acquired antibodies against anthrax
Fig 1
Expression and immunoreactivity of candidate proteins.
(A) Coomassie brilliant blue (CBB) staining and (B–D) Western blotting of the proteins in cell pellet fractions of the control and candidate protein-expressing Escherichia coli strains grown in terrific broth. In Western blotting, the proteins in the cell pellets were probed with different antibodies: (B) anti-glutathione S-transferase (GST) immunoglobulin G; (C) horse hyperimmunized anti-Bacillus anthracis serum (PC1); (D) naive horse serum (NC1). Lane 1, Mw, molecular weight marker (in kDa); lane 2, control strain which is E. coli BL21 harboring empty pGEX-6P-2 without IPTG induction; lane 3, control strain which is E. coli BL21 harboring empty pGEX-6P-2 with 0.2 mM IPTG induction; lane 4, E. coli BTZ001 expressing recombinant hypothetical protein (GST-GBAA_RS28110: 44 kDa); lane 5, E. coli BTZ002 expressing recombinant capsule biosynthesis protein CapA (GST-GBAA_RS28240: 72 kDa); lane 6, E. coli BTZ003 expressing recombinant signal peptidase (GST-GBAA_RS28275: 47 kDa); lane 7, E. coli BTZ004 expressing recombinant peptide ABC substrate-binding protein (GST-GBAA_RS28340: 84 kDa); lane 8, E. coli BTZ005 expressing recombinant metal-dependent hydrolase (GST-GBAA_RS28430: 46 kDa). The arrows indicate target proteins in the expected sizes.