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Introduction: In many studies, immunogenicity of Brucella proteins such as P39 in animals is investigated. In this study, we evaluated antigenicity of recombinant P39 from Brucella abortus in patients with Brucellosis. Materials and Methods: In this experimental study, at first recombinant P39 was produced in Escherichia coli. Sera reactivity of six infected individuals against the recombinant P39 protein was analysed by Western Blot. Results: Data indicated that P39 protein from Brucella abortus was recognized by patients, sera antibodies. Conclusion: Our data showed that recombinant P39 protein can be detected as an antigen by sera in infected human. Therefore, recombinant P39 have same epitopes with natural form of this antigen.

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Background: Vibrio cholera toxin B (CTB) subunit is the pentameric non-toxic portion of cholera toxin (CT) which is responsible for the holotoxin binding to the GM1 ganglioside receptor present on nucleated cells. this study was to produce, purify, and verify recombinant CTB (rCTB) subunitin prokaryotic system. Materials and Methods: In this experimental study, rCTB expression vector (pET-28a) which could be induced in E. coli (BL21) was designed and synthesized. Then the recombinant expression strains containing the result of IPTG interaction were induced and the rCTB was generated on small and large scales. The rCTB produced through Ni2+-charged resin, after refolding and free of possible CTA contaminants, was extracted. After purification, rCTB was verified by Western blotting. Results: The results indicated the level of purification to be about 480µg of purified active pentameric rCTB for each liter of the induced culture. Also, Western blotting analysis showed that recombinant CTB is strongly and specifically recognized by polyclonal antibodies against the cholera toxin. Conclusion: The findings of this study demonstrated that E.coli is an available host for production of CTB. In addition, the designed host and vector can be used in large scale production of this protein