title: Ara h 2 peptides containing dominant CD4+ T-cell epitopes: candidates for a peanut allergy therapeutic.
abstract: BACKGROUND
  Peanut allergy is a life-threatening condition; there is currently no cure. Although whole allergen extracts are used for specific immunotherapy for many allergies, they can cause severe reactions, and even fatalities, in peanut allergy.
  
  
  OBJECTIVE
  This study aimed to identify short, T-cell epitope-based peptides that target allergen-specific CD4(+) T cells but do not bind IgE as candidates for safe peanut-specific immunotherapy.
  
  
  METHODS
  Multiple CD4(+) T-cell lines specific for the major peanut allergen Ara h 2 were generated from PBMCs of 16 HLA-diverse subjects with peanut allergy by using 5,6-carboxyfluorescein diacetate succinimidylester-based methodology. Proliferation and ELISPOT assays were used to identify dominant epitopes recognized by T-cell lines and to confirm recognition by peripheral blood T cells of epitope-based peptides modified for therapeutic production. HLA restriction of core epitope recognition was investigated by using anti-HLA blocking antibodies and HLA genotyping. Serum-IgE peptide-binding was assessed by dot-blot.
  
  
  RESULTS
  Five dominant CD4(+) T-cell epitopes were identified in Ara h 2. In combination, these were presented by HLA-DR, HLA-DP, and HLA-DQ molecules and recognized by T cells from all 16 subjects. Three short peptide variants containing these T-cell epitopes were designed with cysteine-to-serine substitutions to facilitate stability and therapeutic production. Variant peptides showed HLA-binding degeneracy, did not bind peanut-specific serum IgE, and could directly target T(H)2-type T cells in peripheral blood of subjects with allergy.
  
  
  CONCLUSIONS
  Short CD4(+) T-cell epitope-based Ara h 2 peptides were identified as novel candidates for a T-cell-targeted peanut-specific immunotherapy for an HLA-diverse population.
authors.affiliation: Department of Immunology, Monash University, Melbourne, Australia.
authors.forename: Sara R
authors.initials: SR
authors.lastname: Prickett
authors.forename: Astrid L
authors.initials: AL
authors.lastname: Voskamp
authors.forename: April
authors.initials: A
authors.lastname: Dacumos-Hill
authors.forename: Karen
authors.initials: K
authors.lastname: Symons
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Rolland
authors.forename: Robyn E
authors.initials: RE
authors.lastname: O'Hehir
mesh_terms: D055516:2S Albumins, Plant / Q000235:genetics / Q000627:therapeutic use*; D000328:Adult; D052179:Antigens, Plant / Q000235:genetics / Q000627:therapeutic use*; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects*; D018984:Epitopes, T-Lymphocyte / Q000235:genetics / Q000627:therapeutic use*; D006023:Glycoproteins / Q000235:genetics / Q000627:therapeutic use*; D006801:Humans; D007167:Immunotherapy; D021183:Peanut Hypersensitivity / Q000628:therapy*; D010455:Peptides / Q000235:genetics / Q000627:therapeutic use*; D015203:Reproducibility of Results
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D018984:Epitopes, T-Lymphocyte; D006023:Glycoproteins; D010455:Peptides