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Macrophages (MΦ) are the most described and characterized target and host of mycobacteria. Like other cells of innate immunity MΦ have a wide range of receptor molecules which interact with different pathogen associated molecular patterns (PAMPs). Immunodominant proteins MPT63 and MPT83 that are synthesized in abundance by Mycobacterium bovis or Mycobacterium tuberculosis strains could be involved in development of tuberculosis infection. The aim of this study was to search for effects of these mycobacterial antigens on target cells. For this aim full-sized sequences of MPT83 (rMPT83full) and MPT63 antigens were cloned into plasmid pET24a(+). The increase of phagocytic activity of murine peritoneal macrophages was demonstrated, but not of macrophage-like cells from J774 cell line, which were treated by rMPT63 and rMPT83full proteins for 24 h. This effect of such antigens can be considered as a way to facilitate the consumption of mycobacterial cells by macrophages to avoid other effector mechanisms of innate and adaptive immunity.

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. [ABSTRACT FROM AUTHOR]