title: In silico prediction of Ara h 2 T cell epitopes in peanut-allergic children.
abstract: BACKGROUND
  Despite the frequency and severity of peanut allergy, the only approved treatment is strict avoidance. Different types of immunotherapy with crude peanut extract are not universally effective and have been associated with relatively high adverse reaction rates.
  
  
  OBJECTIVE
  We sought to determine whether in silico predictive algorithms were useful in identifying candidate peptides for an Ara h 2 peptide-based vaccine using peanut-allergic patients' peripheral blood mononuclear cells (PBMCs) in vitro. A human leucocyte antigen (HLA) distribution analysis was also performed.
  
  
  METHODS
  Major histocompatibility complex (MHC)-class II-binding peptides were predicted using NetMHCIIpan-2.0 and NetMHCII-2.2 algorithms. PBMCs from 80 peanut-allergic patients were stimulated with overlapping 20-mer Ara h 2 peptides. Cell supernatant cytokine profiles were evaluated by multiplex assays. HLA-DRB1* and HLA-DQB1* typing were performed.
  
  
  RESULTS
  Four regions of overlapping sequences induced PBMC proliferation and predominant Th2 cytokine production. HLA genotyping showed 30 different DRB1* allele specificities and eight DQ serological specificities. The in silico analysis revealed similar relevant regions and predicted identical or similar core 9-mer epitopes to those identified in vitro. If relevant peptides, as determined by either in vitro or in silico analysis (15 peptides and 9 core epitopes respectively), were used in a peptide-based vaccine, they would cover virtually all subjects in the cohort studied.
  
  
  CONCLUSIONS
  Four dominant regions in Ara h 2 have been identified, containing sequences that could serve as potential candidates for peptide-based immunotherapy. MHC-class II-based T cell epitope prediction algorithms for HLA-DR and -DQ loci accurately predicted Ara h 2 T cell epitopes in peanut-allergic subjects, suggesting their potential utility in a peptide-based vaccine design for food allergy.
authors.affiliation: Division of Allergy & Immunology and The Jaffe Food Allergy Research Institute, Mount Sinai School of Medicine, New York, NY, USA.
authors.forename: M
authors.initials: M
authors.lastname: Pascal
authors.forename: G N
authors.initials: GN
authors.lastname: Konstantinou
authors.forename: M
authors.initials: M
authors.lastname: Masilamani
authors.forename: J
authors.initials: J
authors.lastname: Lieberman
authors.forename: H A
authors.initials: HA
authors.lastname: Sampson
mesh_terms: D055516:2S Albumins, Plant / Q000737:chemistry / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry / Q000276:immunology*; D005260:Female; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D021183:Peanut Hypersensitivity / Q000276:immunology*; D055815:Young Adult
chemical_list: D055516:2S Albumins, Plant; D052179:Antigens, Plant; C500890:Ara h 2 allergen, Arachis hypogaea; D018984:Epitopes, T-Lymphocyte; D006023:Glycoproteins; D000949:Histocompatibility Antigens Class II