title: Ara h 1-reactive T cells in individuals with peanut allergy.
abstract: BACKGROUND
  Effective immunotherapy for peanut allergy is hampered by a lack of understanding of peanut-reactive CD4(+) T cells.
  
  
  OBJECTIVE
  To identify, characterize, and track Ara h 1-reactive cells in subjects with peanut allergy by using Ara h 1-specific class II tetramers.
  
  
  METHODS
  Tetramer-guided epitope mapping was used to identify the antigenic peptides within the peanut allergen Ara h 1. Subsequently, HLA class II/Ara h 1-specific tetramers were used to determine the frequency and phenotype of Ara h 1-reactive T cells in subjects with peanut allergy. Cytokine profiles of Ara h 1-reactive T cells were also determined.
  
  
  RESULTS
  Multiple Ara h 1 epitopes with defined HLA restriction were identified. Ara h 1-specific CD4(+) T cells were detected in all of the subjects with peanut allergy tested. Ara h 1-reactive T cells in subjects with allergy expressed CCR4 but did not express CRTH2. The percentage of Ara h1-reactive cells that expressed the β7 integrin was low compared with total CD4(+) T cells. Ara h 1- reactive cells that secreted IFN-γ, IL-4, IL-5, IL-10, and IL-17 were detected.
  
  
  CONCLUSIONS
  In individuals with peanut allergy, Ara h 1-reactive T cells occurred at moderate frequencies, were predominantly CCR4(+) memory cells, and produced IL-4. Class II tetramers can be readily used to detect Ara h 1-reactive T cells in the peripheral blood of subjects with peanut allergy without in vitro expansion and would be effective for tracking peanut-reactive CD4(+) T cells during immunotherapy.
authors: Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA.
authors: Jonathan H
authors: JH
authors: DeLong
authors: Kelly Hetherington
authors: KH
authors: Simpson
authors: Erik
authors: E
authors: Wambre
authors: Eddie A
authors: EA
authors: James
authors: David
authors: D
authors: Robinson
authors: William W
authors: WW
authors: Kwok
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000737:chemistry / Q000276:immunology*; D010367:Arachis / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte; D005260:Female; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D015847:Interleukin-4 / Q000096:biosynthesis; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D008969:Molecular Sequence Data; D021183:Peanut Hypersensitivity / Q000276:immunology*; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology*; D054398:Receptors, CCR4 / Q000378:metabolism; D055815:Young Adult
chemical_list: D052179:Antigens, Plant; C500889:Ara h 1 protein, Arachis hypogaea; C515354:CCR4 protein, human; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; D006023:Glycoproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D054398:Receptors, CCR4; D015847:Interleukin-4