title: Evaluation of the contribution of major T cell subsets to IFN-gamma production in TB infection by ELISPOT.
abstract: Interferon gamma remains a key effector molecule that is still widely used as the most informative biomarker for screening human immune responses against tuberculosis, particularly in ELISPOT assays. We investigated the participation of CD4(+) and CD8(+) T lymphocytes in the PBMC responses to Mycobacterium tuberculosis (Mtb) specific antigens in 33 TB cases and 49 contacts. Responses to ESAT-6 were higher than CFP-10. There was no significant difference in responses to both Mtb antigens between cases and contacts. PBMCs response to ESAT-6 but not CFP-10 in cases was significantly reduced by depletion of CD4(+) cells whereas CD8(+) cell depletion had no impact. In conclusion, ESAT-6 is a more recognized antigen in this population, and CD4(+) lymphocytes are the main participants in IFN-gamma response by ELISPOT. Thus, a decline of CD4(+) T lymphocytes below a critical level might affect the sensitivity of IFN-gamma release assays for detecting Mtb infection.
authors.affiliation: Federal College of Veterinary & Medical Laboratory Technology, National Veterinary Research Institute, Vom, Plateau, Nigeria.
authors.forename: Moses D
authors.initials: MD
authors.lastname: Lugos
authors.forename: Ifedayo M O
authors.initials: IM
authors.lastname: Adetifa
authors.forename: Simon
authors.initials: S
authors.lastname: Donkor
authors.forename: Philip C
authors.initials: PC
authors.lastname: Hill
authors.forename: Richard A
authors.initials: RA
authors.lastname: Adegbola
authors.forename: Martin O C
authors.initials: MO
authors.lastname: Ota
mesh_terms: D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D014376:Tuberculosis / Q000175:diagnosis / Q000276:immunology*; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; C072681:Mycobacterium tuberculosis antigens; D007371:Interferon-gamma