title: Efficient Ex vivo stimulation of Mycobacterium tuberculosis-specific T cells by genetically detoxified Bordetella pertussis adenylate cyclase antigen toxoids.
abstract: Mycobacterium tuberculosis is a significant threat to global health. Mycobacterium bovis BCG vaccine provides only partial protection, and the skin test reagent used to aid diagnosis of both active and latent tuberculosis, purified protein derivative (PPD), lacks specificity and sensitivity. The use of genetically detoxified Bordetella pertussis adenylate cyclase toxin (CyaA) as a delivery system for two immunodominant proteins of M. tuberculosis that are of greater specificity than PPD, early-secreted antigenic target 6-kDa protein (ESAT-6) and culture filtrate protein 10 (CFP-10), was therefore investigated. CyaA toxoids incorporating these antigens were able to restimulate T cells from more than 91% tuberculosis patients and healthy sensitized donors. Delivery of antigen by CyaA decreased by 10-fold the amount of ESAT-6 and CFP-10 required to restimulate T cells, and in low responders, the overall frequency of gamma interferon-producing cells detected by enzyme-linked immunospot assay was increased (P < 0.01 for both antigens). Delivery of ESAT-6 and CFP-10 by CyaA enabled the detection of both CD4(+) and CD8(+) T cells: these responses could be blocked by inhibition of major histocompatibility complex class II or class I, respectively. Covalent linkage of antigen to the CyaA vector was required for enhancement to occur, as a mixture of mock CyaA toxoid plus recombinant ESAT-6 did not lead to enhancement. In a simplified whole-blood model to detect tuberculosis infection, the frequency of positive responses to CFP-10 was increased by CyaA delivery, a potentially important attribute that could facilitate the identification of latent infection.
authors.affiliation: Wellcome Trust Center for Research in Clinical Tropical Medicine, Imperial College London, Wright Fleming Institute, Norfolk Place, London W2 1PG, United Kingdom. r.j.wilkinson@imperial.ac.uk
authors.forename: Katalin A
authors.initials: KA
authors.lastname: Wilkinson
authors.forename: Marcela
authors.initials: M
authors.lastname: Simsova
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Schölvinck
authors.forename: Peter
authors.initials: P
authors.lastname: Sebo
authors.forename: Claude
authors.initials: C
authors.lastname: Leclerc
authors.forename: H Martin
authors.initials: HM
authors.lastname: Vordermeier
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Dickson
authors.forename: Jillian R
authors.initials: JR
authors.lastname: Brown
authors.forename: Robert N
authors.initials: RN
authors.lastname: Davidson
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Pasvol
authors.forename: Michael
authors.initials: M
authors.lastname: Levin
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Wilkinson
mesh_terms: D000262:Adenylyl Cyclases / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D000328:Adult; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D001886:Bordetella pertussis / Q000201:enzymology / Q000235:genetics / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D016503:Drug Delivery Systems; D005260:Female; D006801:Humans; D016056:Immunodominant Epitopes / Q000008:administration & dosage / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D032581:Tuberculosis Vaccines / Q000235:genetics / Q000276:immunology; D014397:Tuberculosis, Pulmonary / Q000276:immunology / Q000517:prevention & control
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D016056:Immunodominant Epitopes; D011993:Recombinant Fusion Proteins; D032581:Tuberculosis Vaccines; D007371:Interferon-gamma; D000262:Adenylyl Cyclases