Category: Other - Immune Aberrations in Human Disease
Human immune deficiency virus type I (HIV-1) and Mycobacterium tuberculosis (M.tb) have become intertwined over a past few decades that exacerbates the morbidity and mortality associated with each pathogen alone. In general, many individuals get infected with Mycobacterium tuberculosis, but fails to develop active tuberculosis. the only available vaccine Mycobacterium bovis Bacilli Calmette Guerin (BCG) fails to stop adult TB cases and successful in the pediatric population only. Thus, the development of an effective and improved anti-TB vaccine has become an urgent need for control and elimination of this disease. M.smegmatis strains which are nonpathogenic and commensal in humans are used in this study for cloning two immunodominant antigens namely HspX and Mpt51.The HspX is a latency associated immunodominant antigen of M. tuberculosis. Mpt 51 has been reported to be highly expressed during the re-activation of tuberculosis particularly in HIV positive individuals.
Characterization of recombinant M. smegmatis expressing hspX and mpt51 was carried out by growth curve analysis and induction of the monocytes. Recombinant strain containing hspX was found to play a vital role in the survival of bacterium under stress conditions like acidic and microaerophilic conditions and also changed the morphology of bacterium when compared with the strain containing mpt51. Recombinant strains with hspX differentiated monocytes into macrophages efficiently than the strain with mpt51. The Realtime PCR analysis revealed that Th1 cytokines were more upregulated by M. smegmatis containing hspX than by M. smegmatis containing mpt51. The efficiency of the above vaccine strains will be discussed in detail.