Evaluating the Performance of PPE44, HSPX, ESAT-6 and CFP-10 Factors in Tuberculosis Subunit Vaccines

Mycobacterium tuberculosis (M. tuberculosis) is an intracellular pathogen causing long-term infection in humans that mainly attacks macrophages and can escape from the immune system with the various mechanisms. The only FDA-approved vaccine against M. tuberculosis (MTB) is Mycobacterium bovis bacillus Calmette-Guérin (BCG). The protection of this vaccine typically lasts 10–15 years. Due to the increasing number of people becoming ill with MTB each year worldwide, the need to develop a new effective treatment against the disease has been increased. During the past two decades, the research budget for TB vaccine has quadrupled to over half a billion dollars. Most of these research projects were based on amplifying and stimulating the response of T-cells and developing the subunit vaccines. Additionally, these studies have demonstrated that secretory and immunogenic proteins of MTB play a key role in the pathogenesis of the bacteria. Therefore, these proteins were used to develop the new subunit vaccines. In this review, based on the use of these proteins in the successful new subunit vaccines, the PPE44, HSPX, CFP-10 and ESAT-6 antigens were selected and the role of these antigens in designing and developing new subunit vaccines against TB and for the prevention of TB were investigated.

In Silico Design of Multi-Epitope ESAT-6:Ag85b:Fcγ2a Fusion Protein as a Novel Candidate for Tuberculosis Vaccine

: Mycobacterium tuberculosis (MTB), which is the causative agent of tuberculosis (TB), is among the most important infectious bacteria with high morbidity and mortality rates worldwide. Bacilli Calmette-Guerin (BCG) vaccine has been discovered for about a century, and it is considered as a major vaccine for humans. However, some factors, such as its attenuated nature and its inefficacy against the latent form of the disease, have led to the use of alternative vaccines. Multi-epitope subunit vaccines are new-generation vaccines that are being developed in clinical trial phases. For the production of a subunit vaccine, the selection of immunodominant antigens and targeted delivery systems to antigen presenting cells (APCs) are considered as basic parameters. In the present study, we designed the novel multi-epitope ESAT-6:Ag85B:Fcγ2a, which was evaluated completely by various online tools as an optimum vaccine against TB. The early secreted antigenic target of 6 kDa (ESAT-6) and antigen 85B (Ag85B) are two immunodominant antigens, and Fcγ2a is a targeted delivery system. This vaccine candidate can be used for future preclinical studies.