title: Extensive sequence homology between the mycobacterium leprae LSR (12 kDa) antigen and its Mycobacterium tuberculosis counterpart.
abstract: The Mycobacterium leprae LSR (12 kDa) protein antigen has been reported to mimic whole cell M. leprae in T cell responses across the leprosy spectrum. In addition, B cell responses to specific sequences within the LSR antigen have been shown to be associated with immunopathological responses in leprosy patients with erythema nodosum leprosum. We have in the present study applied the M. leprae LSR DNA sequence as query to search for the presence of homologous genes within the recently completed Mycobacterium tuberculosis genome database (Sanger Centre, UK). By using the BLASTN search tool, a homologous M. tuberculosis open reading frame (336 bp), encoding a protein antigen of 12.1 kDa, was identified within the cosmid MTCY07H7B.25. The gene is designated Rv3597c within the M. tuberculosis H37Rv genome. Sequence alignment revealed 93% identity between the M. leprae and M. tuberculosis antigens at the amino acid sequence level. The finding that some B and T cell epitopes were localized to regions with amino acid substitutions may account for the putative differential responsiveness to this antigen in tuberculosis and leprosy.
authors.affiliation: Department of Vaccinology, National Institute of Public Health, P.O. Box 4404, Torhov, N-0403, Oslo, Norway. fredrik.oftung@folkehelsa.no
authors.forename: F
authors.initials: F
authors.lastname: Oftung
authors.forename: A S
authors.initials: AS
authors.lastname: Mustafa
authors.forename: H G
authors.initials: HG
authors.lastname: Wiker
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000737:chemistry*; D006801:Humans; D008969:Molecular Sequence Data; D009166:Mycobacterium leprae / Q000235:genetics / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C084997:LSR2 protein, Mycobacterium leprae; D011993:Recombinant Fusion Proteins