Comparison of the Titers of Produced Antibodies against BLF1 and BLF1-STxB Recombinant Proteins in Laboratory Rats

Burkholderia pseudomallei causing Melioidosis and Shigella dysenteriae is the most common cause of diarrhea, and so far no effective vaccine has been produced against these two bacteria. The BLF1 protein of Burkholderia pseudomallei bacteria plays an important role in pathogenesis and infection. Shigella dysentery STxB is one of the most important factors in pathogenesis and also has an adjuvant role. Binding the BLF1 protein with STxB can be a good candidate vaccine. In this study, the antibody titers of BLF1-STxB and BLF1 proteins produced in rats were compared.    In this experimental study, pET28a (+) - blf1-stxB and pET28a (+) - blf1 vectors were transformed into E. coli BL21 (DE3) and confirmed by PCR. The expression of blf1-stxB and blf1 genes was induced by IPTG and the proteins were injected into rats four times after purification of the protein by using an affinity chromatography column. Polyclonal antibodies produced in the serum of rats were measured.   The produced recombinant proteins were approved by SDS-PAGE and Western blotting. ELISA results showed that antibody was produced against the BLF1 antigen and the antibody titer level increased by STxB binding to BLF1, compared with the antibody titer against the BLF1 antigen.   The BLF1-STxB protein had higher antibody titer than BLF1. Due to the structural similarity of STxB subunit with its counterpart in E. coli, it can be a vaccine candidate against Burkholderia pseudomallei, Shigella dysenteriae, enterohemorrhagic E. coli, and enterotoxigenic E. coli.