Computational Mapping of Class I HLA-A Specific Cytotoxic T Lymphocyte Epitopes of Mycobacterium tuberculosis and Their Potential Role in Vaccine Design

Objective: Tuberculosis (TB) caused by Mycobacterium tuberculosis (M. tb) is one of the deadliest diseases causing millions of deaths worldwide. Bacillus Calmette-Guerin (BCG) is the only vaccine that has been used in many countries where TB is prevalent. Despite vaccination, this disease prevails in many of the developing countries, necessitating the development of an effective vaccine against TB. Since M. tb acts as an intracellular pathogen, cell-mediated immune response plays an important role in disease control. Therefore, screening of CD8+ T cell epitopes of M. tb antigens could aid in the development of an effective vaccine against TB. In the current study, a reverse vaccinology approach was utilized to predict and map cytotoxic T lymphocyte (CTL) epitopes in the virulent proteins that are also essential for M. tb. Materials and Methods: Database of Essential Genes and Virulence Factor Database were used for identifying the virulent proteins of M. tb and their antigenicity was assessed using VaxiJen server. Various immunoinformatics tools were used to predict MHC class I binding, MHC processing, immunogenicity, toxicity and allergenicity. Results: Twelve M. tb antigens were selected for the prediction analyses using various tools. The results indicated the presence of 20 novel CTL epitopes predicted against human HLA-A alleles. This study has also screened for multiple allele binding epitopes that could be used as a vaccine component. Conclusion: This study has yielded a few hitherto unreported CTL epitopes binding to class I HLA-A alleles. Further experimental validation is necessary for confirming their potential as vaccine candidates.