In silico identification of cytotoxic T lymphocyte epitopes encoded by RD5 region of Mycobacterium tuberculosis

Introduction: While CD8+ T cells (cytotoxic T lymphocytes, CTLs) play important roles in immunity against Mycobacterium tuberculosis, only a small number of human leukocyte differentiation antigen (HLA) class I-restricted CTL epitopes for TB have been identified. The current study evaluates CTL epitopes of Rv3117 and Rv3120 proteins, two newly found M. tuberculosis region-diffference-5 (RD5)-encoded antigens, and their population coverage. Methodology: The amino acid sequences of the two proteins were subjected to epitope analysis under HLA-A2, A3 and B7 supertype restriction using NetCTL, SYFPEITHI, BIMAS, NetCTLPan, IEDB, NetMHC and NetMHCPan prediction online servers. Results: Eight RD5-encoded CTL epitopes were identified in the two proteins and the average population coverage of these epitopes was 87.2% among populations worldwide. Conclusion: These CTL epitopes that were identified in silico and may have potential use for CD8+ T cell-mediated TB vaccine design.