title: Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test.
abstract: The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.
authors.affiliation: Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.
authors.forename: Bosco Christiano Maciel da
authors.initials: BC
authors.lastname: Silva
authors.affiliation: Laboratório Avançado de Saúde Pública, Fundação Oswaldo Cruz, Salvador, BA, Brasil.
authors.forename: Maria Fernanda Rios
authors.initials: MF
authors.lastname: Grassi
authors.affiliation: Laboratório Avançado de Saúde Pública, Fundação Oswaldo Cruz, Salvador, BA, Brasil.
authors.forename: Raimundo
authors.initials: R
authors.lastname: Coutinho
authors.affiliation: Laboratório Avançado de Saúde Pública, Fundação Oswaldo Cruz, Salvador, BA, Brasil.
authors.forename: Rita Elizabeth Moreira
authors.initials: RE
authors.lastname: Mascarenhas
authors.affiliation: Laboratório Avançado de Saúde Pública, Fundação Oswaldo Cruz, Salvador, BA, Brasil.
authors.forename: Viviana Nilla
authors.initials: VN
authors.lastname: Olavarria
authors.affiliation: Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.
authors.forename: Adriana
authors.initials: A
authors.lastname: Coutinho-Borgo
authors.affiliation: Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.
authors.forename: Jorge
authors.initials: J
authors.lastname: Kalil
authors.affiliation: Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.
authors.forename: Edecio
authors.initials: E
authors.lastname: Cunha Neto
authors.affiliation: Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.
authors.forename: Simone Gonçalves
authors.initials: SG
authors.lastname: Fonseca
mesh_terms: D000328:Adult; D000465:Algorithms; D000942:Antigens, Bacterial / Q000032:analysis; D001426:Bacterial Proteins / Q000097:blood; D015415:Biomarkers / Q000032:analysis; D001938:Brazil; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018833:Chaperonins / Q000097:blood; D058501:Enzyme-Linked Immunospot Assay; D018604:Epitope Mapping; D000939:Epitopes / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology; D064368:Healthy Volunteers; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D028044:Phosphate-Binding Proteins / Q000097:blood; D014374:Tuberculin Test
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D015415:Biomarkers; D000939:Epitopes; C097970:GroESL protein, Bacteria; D006684:HLA-DR Antigens; D028044:Phosphate-Binding Proteins; D007371:Interferon-gamma; D018833:Chaperonins