Tuberculosis (TB) is referred to as a disease of the past; however, the reality is TB is one of the top 10 infectious disease that causes death worldwide and a leading killer of HIV-positive people.
According to the World Health Organization, about 1.6 billion people (with the inclusion of 0.3 million among people with HIV) die of TB. TB bacterium known as Mycobacteria tuberculosis (M. tb).
It typically attacks the lungs to cause infectious pulmonary tuberculosis. This spreads to other people via inhalation. However the disease also target other body tissues such as brain, digestive system, bones and urinary tract etc.
Eradication of M. tb is quite challenging due to several factors. Treatment with antibiotics is expensive, current chemotherapeutic regimens require more than 6 months treatment with multiple drugs; increasing occurrence of drug resistance, and the development of potent less expensive new drugs for TB treatment have been slow.
The available Bacillus Calmette-Guerin (BCG) vaccine licensed for human use only provides protection to young children, however it is less effective in adults.
Despite the progress made in the past years searching for a new and more effective TB vaccine, the scientific community is still pursuing this goal due to the complexity of the bacteria.
Thus, there is limited information and understanding of the mechanism through which this bacteria infect and cause disease in human.
M. tb uses multiple strategies to sustain itself in a variety of host environments; and to escape from the host’s immune response. M. tb cell wall represents the major determinants of mycobacterial virulence.
Cell wall protein, lipid and carbohydrate components have been the subject of interest for developing new vaccines; due to the role they play in the survival and virulence of the bacteria.
These cell wall components mediate the interactions between M. tb and the host immune system. Recognition of these components by the host immune system is crucial in determining the subsequent specific immune response against the bacteria.
Considering the crucial role of played by these products in the infection process, the use of these products as a target for vaccine development has dominated the efforts for the development of new generation vaccines against TB.
So far, significant progress has been made in understanding the interaction of these bacteria components; and human immune cells in the field of TB research over the past decades.
However, there are still remarkable challenges that need to be conquered; in order to speed up the development of more efficient vaccines against TB in the next few years.