Failure of BCG Necessitates to the Development of New Novel Vaccine

Abstract

The only vaccine available for the deadly disease tuberculosis is Bacillus- Calmette-Guerin (BCG), which is an attenuated vaccine of Mycobacterium bovis. Although this vaccine boosts immune response but it is effective only for 10-20 years, after this there is need to develop immunity against Mycobacterium tuberculosis H37Rv (M. tuberculosis). As the vaccine is botched to provide sustained effects and to protect against disseminated forms of Tuberculosis (TB), it needs a component to heighten antigen specific immune reactions when used in combination with particular vaccine antigens that can also modulate the immune responses to an antigen to advance them. Adjuvants are the one such factor that can be used in vaccines to crack such problems. Many vaccines are under clinical trials in which subunit vaccine has taken attention because they are safer and can be standardized. There are many adjuvants which have been tested in combinations with BCG to increase the activity of vaccine. Mycobacterial antigen 85 A, B, C, present at outer part of cell wall and have great potential as therapeutic approach towards tuberculosis. MPT64 increases T-cell response in tuberculosis patients but there are less evidence about the role of this secreted mycobacterial protein in patients. ESAT 6 is effective T cell antigen and also pore forming toxin which is crucial for the virulence of bacterium. ESAT 6 separately or in compound form with its chaperone CFP- 10 form, regulates host immune response. They efficiently modify innate and adaptive immune response. This review provides an insight in the direction of the vaccine development on the basis of pre-existing credentials.