Immunotherapeutic Potential of Mycobacterium indicus pranii Against Tuberculosis

Mycobacterium indicus pranii (MIP), a nonpathogenic saprophytic mycobacterium, is potential tuberculosis (TB) vaccine candidate as it shares a large number of cross-reactive antigens with M.tb and has demonstrated unique ability for immunomodulation. Studies in animal models of TB have demonstrated its significant prophylactic and therapeutic efficacy against TB. The immunological aspects of MIP-mediated protection include induction of Th1 and Th17 type of response, activation of macrophage effector functions, and CD4+ T cell activation along with enhanced CD8+ T cell cytotoxic activity, thereby resulting in inhibition of the intracellular growth and multiplication of M.tb. When used as a booster to BCG vaccine, MIP conferred higher protection in animal models of TB. Protective efficacy of killed MIP vaccine has been established in clinical trials. Immunotherapeutic potential of this vaccine is confirmed in a recently conducted multicentric clinical trial in category II TB patients, having advanced disease, and was difficult to treat. Moreover, practical implementation of MIP as TB vaccine has a major advantage as it is a cost-effective vaccination strategy for effective control of TB with no adverse effects.