title: CD4+ T-cell responses to recombinant hsp65 and hsp18 of M. leprae and their trypsin-digested fragments in leprosy: diversity in HLA-DR restriction.
abstract: Mycobacterium leprae heat-shock proteins hsp65 and hsp18 have received immense attention as major T-cell target antigens in leprosy. Both of these hsps and their tryptic fragments were characterized for their ability to stimulate CD4+ T cells derived from polar leprosy cases and healthy contacts. The optimal digestion of hsps with trypsin yielded four fragments of hsp65--TDB65-1 (24 kDa), TDB65-2 (18 kDa), TDB65-3 (17 kDa), TDB65-4 (14 kDa)-- and three of hsp18--TDB18-1 (10 kDa), TDB18-2 (5 kDa), TDB18-3 (3 kDa). While all of these tryptic fragments and undigested hsps triggered CD4+ T cells from tuberculoid (TT) leprosy patients and healthy contacts (SI > 2), only two fragments--TDB65-2 and TDB18-3--were found to be stimulatory in anergic lepromatous (LL) leprosy patients (SI = 5.27 and 3.0, respectively). Blocking studies using allele-specific anti-DR monoclonal antibodies revealed multiple HLA-Dr restriction, with DR2 providing the strongest restriction in both TT as well as LL leprosy. These findings indicate that M. leprae hsps and their trypsin-digested fragments are promiscuous and recognizable in the context of diverse HLA alleles, of which DR2 is the most efficient restriction element. The 18-kDa fragment of hsp65 and the 3-kDa fragment of hsp18 are the most versatile fragments that could elicit in vitro proliferation in both polar forms of leprosy.
authors.affiliation: Histocompatibility and Immunogenetics Department, All India Institute of Medical Sciences, New Delhi, India.
authors.forename: D K
authors.initials: DK
authors.lastname: Mitra
authors.forename: N K
authors.initials: NK
authors.lastname: Mehra
authors.forename: T K
authors.initials: TK
authors.lastname: Maiti
authors.forename: A
authors.initials: A
authors.lastname: Banerjee
authors.forename: V
authors.initials: V
authors.lastname: Taneja
authors.forename: R
authors.initials: R
authors.lastname: Rajalingam
authors.forename: R K
authors.initials: RK
authors.lastname: Ahuja
authors.forename: B C
authors.initials: BC
authors.lastname: Bhattacharya
mesh_terms: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018834:Chaperonin 60; D018833:Chaperonins / Q000276:immunology*; D006684:HLA-DR Antigens / Q000032:analysis / Q000276:immunology; D006360:Heat-Shock Proteins / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D007918:Leprosy / Q000276:immunology*; D015440:Leprosy, Lepromatous / Q000276:immunology; D015441:Leprosy, Tuberculoid / Q000276:immunology; D008213:Lymphocyte Activation; D009166:Mycobacterium leprae / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology; D014357:Trypsin
chemical_list: D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D018834:Chaperonin 60; D006684:HLA-DR Antigens; D006360:Heat-Shock Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; C074119:heat-shock protein 65, Mycobacterium; C081475:hsp18 protein, bacteria; D014357:Trypsin; D018833:Chaperonins