MAPPING OF MULTIPLE HLA CLASS II-RESTRICTED T-CELL EPITOPES OF THE MYCOBACTERIAL 70-KILODALTON HEAT-SHOCK PROTEIN

By combining a DNA subclone and synthetic-peptide approach, we mapped epitopes of the immunogenic mycobacterial 70-kDa heat shock protein (H SP70) recognized by human CD4(+) T-cell clones and lines. In addition, we identified the respective HLA-DR molecules used in antigen present ation. The donor groups used were healthy persons immunized with kille d Mycobacterium leprae and tuberculoid leprosy patients. The results s how that the N-terminal part of the HSP70 molecule contains three diff erent T-cell epitopes, of which two were presented by DR7 (amino acids [aa] 66 to 82 and 210 to 226) and one was presented by DR3 (aa 262 to 274). The C-terminal part contains one epitope (aa 413 to 424) presen ted by HLA-DR2. The C-terminal epitope shows extensive homology to the corresponding region of the human HSP70 sequence. Ah of the T-cell ep itopes identified were presented by only one particular HLA-DR molecul e. We also found that HLA-DR5 and DRw53 can present HSP70 to T cells, demonstrating the presence of additional epitopes not yet defined at t he peptide level. On the basis of the donors used in this study, recog nition of HSP IO at the epitope level seems to be ruled by the restric tion elements expressed by the donor rather than by any difference in reactivity between healthy individuals and patients. In conclusion, my cobacterial HSP70 is relevant to subunit vaccine design since it conta ins a variety of T-cell epitopes presented in the context of multiple HLA-DR molecules.