Prediction and identification of HLA-A * 0201 restricted CD8+ CTL epitope in Mycobacterium tuberculosis Ag85C / 第二军医大学学报

ABSTRACT

Objective: To predict and identify HLA-A * 0201 restricted CD8+ CTL epitopes in Mycobacterium tuberculosis (Mtb) antigen Ag85C, so as to provide evidence for epitope-based study for tuberculosis (TB) vaccine. Methods: The online database SYFPEITHI was applied to predict the potential HLA-A * 0201 restricted epitopes from Ag85C, an antigen of Mycobacterium tuberculosis. T2 cell line was used to assay the affinity between the predicted peptides and HLA-A * 0201 molecules. The specific CTL lines were induced from peripheral blood mononuclear cells (PBMCs) of HLA-A * 0201 positive TB patients and PPD+ healthy donors by peptides with high binding affinity to HLA-A * 0201 molecules. IFN-γ production, in vitro proliferation and cytotoxicity of peptide-induced CTL were determined to screen HLA-A * 0201 restricted CD8+ CTL epitopes from those candidates. Results: Fourteen potential epitopes were identified from the SYFPEITHI database. After binding affinity assay, 3 of the 14 peptides (170-178 aa, 317-325 aa, and 144-153 aa) were found to have high binding affinity to HLA-A * 0201 molecules. However, only one peptide (144-153 aa) stimulated its specific CTL to release IFN-γ, proliferate in vitro and produce specific cytotoxicity. Conclusion: We have successfully identified a HLA-A * 0201 restricted CD8+ CTL epitope of Mtb Ag85C-FLTREMPAWL(144-153 aa), which might be a candidate epitope for TB vaccine designing. Our findings provides a basis for developing novel and effective anti-TB vaccine.