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Identification of an HLA-A*0201-Restricted T-Cell Epitope on the MPT51 Protein, a Major Secreted Protein Derived from Mycobacterium tuberculosis, by MPT51 Overlapping Peptide Screening
- Aoshi, Taiki, Nagata, Toshi, Suzuki, Mina, Uchijima, Masato, Hashimoto, Dai, Rafiei, Alireza, Suda, Takafumi, Chida, Kingo, Koide, Yukio
- Infection and immunity 2008 v.76 no.4 pp. 1565-1571
- CD8-positive T-lymphocytes, Mycobacterium tuberculosis, algorithms, epitopes, flow cytometry, interferon-gamma, major histocompatibility complex, mice, plasmids, screening, splenocytes, synthetic peptides, tuberculin, tuberculosis, vaccine development
- CD8⁺ T cells play a pivotal role in protection against Mycobacterium tuberculosis infection. We identified a novel HLA-A*0201-restricted CD8⁺ T-cell epitope on a dominant secreted antigen of M. tuberculosis, MPT51, in HLA-A*0201 transgenic HHD mice. HHD mice were immunized with plasmid DNA encoding MPT51 with gene gun bombardment, and gamma interferon (IFN-γ) production by the immune splenocytes was analyzed. In response to overlapping synthetic peptides covering the mature MPT51 sequence, the splenocytes were stimulated to produce IFN-γ by only one peptide, p51-70. Three-color flow cytometric analysis of intracellular IFN-γ and cell surface CD4 and CD8 staining revealed that the MPT51 p51-70 peptide contains an immunodominant CD8⁺ T-cell epitope. Further analysis using computer algorithms permitted identification of a bona fide T-cell epitope, p53-62. A major histocompatibility complex class I stabilization assay using T2 cells confirmed that this epitope binds to HLA-A*0201. The T cells were capable of lysing MPT51 p53-62 peptide-pulsed T2 cells. In addition, MPT51 p53-62-specific memory CD8⁺ T cells were found in tuberculin skin test-positive HLA-A*0201⁺ healthy individuals. Use of this HLA-A*0201-restricted CD8⁺ T-cell epitope for analysis of the role of MPT51-specific T cells in M. tuberculosis infection and for design of vaccines against tuberculosis is feasible.