identification of mycobacterium tuberculosis ctl epitopes restricted by hla-a*0201 in hhd mice

cd8+ t cells are thought to play an important role in protective immunity to tuberculosis. the major histocompatibility complex class i subtype hla-a*0201 is one of the most prevalent class i alleles, with a frequency of over 30% in most populations. hla-a*0201 transgenic, h-2db/mouse beta2-microglobulin double-knockout mice (hhd) which express human hla-a*0201 but no mouse class i, was shown to provide a powerful model for studying induction of hla-a*0201-restricted immune responses in vivo. methods: hhd mice were immunized with plasmid dna encoding mpb51 by using a gene gun, and ifn-g production from the immune spleen cells was analyzed in response to a synthetic overlapping peptide library covering the mature mpb51 sequence. catatonic t lymphocytes (ctl) activity was measured using cytotoxicity assay and the three-color flowcytometry was used to reveal ifn-g-producing immune spleen cells. results: our findings were shown that only one peptide, p51-70, appeared to stimulate the immune splenocytes to produce ifn-g. flow cytometric analysis with intracellular ifn-g and the t-cell phenotype revealed that the p51-70 peptide contains an immunodominant cd8+ t-cell epitope. further analysis with computer-assisted algorithms permitted identification of a t-cell nona mer epitope, p54-62. finally, we proved that the p54-62/hla-a*0201 complex is strongly recognized by hla class i-restricted cd8+ mpb51-specific ctl cells. conclusion: these results suggest that vaccination with mpb51 gene elicited mpb51-specific ctl. in addition, the p54-62 epitope thus represent potential subunit component for the design of vaccines against tuberculosis.