Expression of Mycobacterium tuberculosis proteins MPT63 and MPT83 as a fusion: purification, refolding and immunological characterization

Proteins MPT63 and MPT83 which are common for both Mycobacterium tuberculosis and Mycobacterium bovis, due to their high immunogenicity, are thought to play a promising role in the development of immunodiagnostic reagents and vaccines. To enhance the antigenic and immunogenic properties of these proteins, fragments of the mpt83 and mpt63 genes were fused in tandem. In this article we present an effective method for the MPT63-MPT83 fusion product purification by metal-affinity chromatography and in vitro refolding. Our results demonstrate that the antigenic properties of the recombinant proteins obtained are comparable to their native analogues. The anti-rMPT63 and anti-rMPT83 sera were found to be highly reactive against the rMPT63-MPT83 fusion protein, which suggests that the fusion protein retains the antigenic properties of the parent proteins. Our results may potentially contribute to the development of improved diagnostic tools or vaccines against human and/or cattle tuberculosis.