Hansen CS, et al. (2016) “Linear epitope mapping of peanut allergens demonstrates individualized and persistent antibody binding patterns.” J Allergy Clin Immunol. 138: 1728-30. doi: 10.1016/j.jaci.2016.06.019
Peanut allergy is considered a major health problem due to its prevalence, persistence, and association with severe symptoms.1 Previous studies suggest that clinical reactivity to allergens might be related to allergen-specific IgE epitope patterns, diversity, and avidity, all of which likely play a role in the effect of IgE on basophils and mast cells.2, 3 Previous peptide microarray-based studies have demonstrated a pronounced heterogeneity in the epitope-binding patterns between individual allergic patients apart from a few immunodominant epitopes.2, 4, 5, 6, 7 Furthermore, elevated IgG4 levels have been associated with protective effects.8Here, high-density peptide arrays were applied to map linear IgE and IgG4 epitopes at the single amino acid level. The peptide arrays contained tiled arrays of 12-mer peptides covering the peanut allergens Ara h 1, 2, 3, 6, 8, and 9. Corresponding peptides with alanine substitutions were used to obtain single amino acid resolution of epitopes and their immune reactivity. Maps of IgE and IgG4 reactivity were obtained for 5 control subjects and 6 severely allergic patients (ages 8-40 years) sampled across 4 to 10 years (see Table E1 and the Methods section in this article’s Online Repository at www.jacionline.org).Sera from peanut-allergic patients (P1-P6) had extensive IgE and IgG4 reactivity against peanut allergens compared with sera from control subjects (see Fig E1 in this article’s Online Repository at www.jacionline.org). Reactivity was mostly toward Ara h 1, 2, and 3 (see Figs E2-E4 in this article’s Online Repository at www.jacionline.org), which corroborates previous studies.2, 5 Corresponding results using alanine substitutions are shown in Fig 1 and Figs E5-E7 in this article’s Online Repository at www.jacionline.org and provide detailed information about the reactivity to the respective epitopes. IgE and IgG4 binding patterns were heterogeneous between patients but very similar for each patient over time. Some regions, for example, region 85-95 of Ara h 1, were reactive to all investigated patient sera, whereas other regions, for example, 285-300 of Ara h 1, were reactive to some but not all patient sera. The majority of these prevalent regions overlapped with previously described prevalent regions (detailed in Table E2 in this article’s Online Repository at www.jacionline.org).