Ara h 1 CD4+ T cell epitope-based peptides: candidates for a peanut allergy therapeutic

Clin Exp Allergy. 2013 Jun;43(6):684-97. doi: 10.1111/cea.12113.

Abstract

Background: Peanut allergy is a life-threatening condition; there is currently no cure. While whole allergen extracts are used for specific immunotherapy for many allergies, they can cause severe reactions and even fatalities in peanut allergy.

Objective: To identify short, HLA-degenerate CD4(+) T cell epitope-based peptides of the major peanut allergen Ara h 1 that target allergen-specific T cells without causing IgE-mediated inflammatory cell activation, as candidates for safe peanut-specific immunotherapy.

Methods: Ara h 1-specific CD4(+) T cell lines (TCL) were generated from peripheral blood mononuclear cells (PBMC) of peanut-allergic subjects using CFSE-based methodology. T cell epitopes were identified using CFSE and thymidine-based proliferation assays. Epitope HLA-restriction was investigated using blocking antibodies, HLA-genotyping and epitope prediction algorithms. Functional peanut-specific IgE reactivity to peptides was assessed by basophil activation assay.

Results: A total of 145 Ara h 1-specific TCL were generated from 18 HLA-diverse peanut-allergic subjects. The TCL recognized 20-mer peptides throughout Ara h 1. Nine 20-mers containing the most frequently recognized epitopes were selected and their recognition confirmed in 18 additional peanut-allergic subjects. Ten core epitopes were mapped within these 20-mers. These were HLA-DQ and/or HLA-DR restricted, with each presented on at least two different HLA-molecules. Seven short (≤ 20 aa) non-basophil-reactive peptides encompassing all core epitopes were designed and validated in peanut-allergic donor PBMC T cell assays.

Conclusions and clinical relevance: Short CD4(+) T cell epitope-based Ara h 1 peptides were identified as novel candidates for a safe, T cell targeted peanut-specific immunotherapy for HLA-diverse populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Antigens, Plant / immunology*
  • Basophils / immunology
  • CD4-Positive T-Lymphocytes / immunology*
  • Epitope Mapping
  • Epitopes, T-Lymphocyte / chemistry
  • Epitopes, T-Lymphocyte / immunology*
  • Glycoproteins / immunology*
  • Histocompatibility Antigens Class II / immunology
  • Humans
  • Immunoglobulin E / blood
  • Immunoglobulin E / immunology
  • Lymphocyte Activation / immunology
  • Membrane Proteins
  • Molecular Sequence Data
  • Peanut Hypersensitivity / immunology*
  • Peptides / chemistry
  • Peptides / immunology*
  • Plant Proteins / immunology*

Substances

  • Antigens, Plant
  • Ara h 1 protein, Arachis hypogaea
  • Epitopes, T-Lymphocyte
  • Glycoproteins
  • Histocompatibility Antigens Class II
  • Membrane Proteins
  • Peptides
  • Plant Proteins
  • Immunoglobulin E