title: A novel allergen-adjuvant conjugate suitable for specific immunotherapy of respiratory allergy.
abstract: BACKGROUND
  Several approaches to find a better adjuvant, focus immunomodulation, and reduce allergenicity are under investigation to improve the efficacy and safety of specific immunotherapy.
  
  
  OBJECTIVE
  We performed an investigation of the in vitro and in vivo effects of a purified allergen chemically conjugated to a novel 8-OH modified adenine as an adjuvant.
  
  
  METHODS
  Purified group 2 major allergen from house dust mite chemically conjugated to 4-(6-amino-9-benzyl-8-hydroxy-9H-purin-2-ylsulfanyl)-butyric acid succinimidyl ester was analyzed by using mass spectrometry. The adduct (nDer p 2-Conj) was assayed for Toll-like receptor activation on transfected HEK293 cells, stimulation of innate cells, and effects on the functional phenotype of specific T-cell lines and clones by means of flow cytometry, real-time PCR, and expression of TH-related transcription factors. Lung cells and sera of nDer p 2-Conj-sensitized C57Bl/6 mice were studied by means of cytology, histology, real-time PCR, and ELISA.
  
  
  RESULTS
  nDer p 2-Conj stimulated IL-12 and IFN-α production from monocytes and plasmacytoid dendritic cells, respectively, retaining the ability to trigger Toll-like receptor 7 exclusively, and expanded human allergen-specific lymphocytes with reduced ability to produce T(H)2-related cytokines and increased IFN-γ levels, as based on GATA-3/T-bet expression. In vivo adduct-sensitized mice exhibited reduced eosinophil infiltration and IL-13 expression in the airways, IFN-γ upregulation together with IgE downregulation, and an increase in allergen-specific IgG(2a) levels in sera. The conjugate exhibited reduced ability to activate human FcεRI(+) cells without inducing T(H)17 cells or autoantibodies.
  
  
  CONCLUSIONS
  The codelivery of an allergen with a modified adenine as a conjugate inducing modulatory cytokines from innate cells redirects in vitro and in vivo pathogenic TH2 responses without eliciting harmful effects.
authors.affiliation: Department of Experimental and Clinical Medicine, Centre for Research, Transfer and High Education DENOTHE, University of Florence, Florence, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Filì
authors.forename: Alessandra
authors.initials: A
authors.lastname: Vultaggio
authors.forename: Elisa
authors.initials: E
authors.lastname: Cardilicchia
authors.forename: Cinzia
authors.initials: C
authors.lastname: Manuelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Casini
authors.forename: Francesca
authors.initials: F
authors.lastname: Nencini
authors.forename: Laura
authors.initials: L
authors.lastname: Maggi
authors.forename: Sara
authors.initials: S
authors.lastname: Pratesi
authors.forename: Giulia
authors.initials: G
authors.lastname: Petroni
authors.forename: Francesca
authors.initials: F
authors.lastname: Boscaro
authors.forename: Antonio
authors.initials: A
authors.lastname: Guarna
authors.forename: Ernesto G
authors.initials: EG
authors.lastname: Occhiato
authors.forename: Sergio
authors.initials: S
authors.lastname: Romagnani
authors.forename: Enrico
authors.initials: E
authors.lastname: Maggi
authors.forename: Paola
authors.initials: P
authors.lastname: Parronchi
mesh_terms: D000818:Animals; D039741:Antigens, Dermatophagoides / Q000276:immunology*; D060829:Arthropod Proteins / Q000276:immunology*; D015551:Autoimmunity; D001491:Basophils / Q000276:immunology; D003888:Desensitization, Immunologic; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D006967:Hypersensitivity / Q000628:therapy*; D007113:Immunity, Innate; D007073:Immunoglobulin E / Q000276:immunology; D007371:Interferon-gamma / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D018418:Th2 Cells / Q000276:immunology; D051193:Toll-Like Receptors / Q000502:physiology
chemical_list: D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; C451163:Dermatophagoides pteronyssinus antigen p 2; D051193:Toll-Like Receptors; D007073:Immunoglobulin E; D007371:Interferon-gamma