Screening and identification of mimotopes of the major shrimp allergen tropomyosin using one-bead-one-compound peptide libraries

Abstract

The one-bead-one-compound (OBOC) combinatorial peptide library is a powerful tool to identify ligand and receptor interactions. Here, we applied the OBOC library technology to identify mimotopes specific to the immunoglobulin E (IgE) epitopes of the major shellfish allergen tropomyosin. OBOC peptide libraries with 8-12 amino acid residues were screened with serum samples from patients with shellfish allergy for IgE mimotopes of tropomyosin. Twenty-five mimotopes were identified from the screening and their binding reactivity to tropomyosin-specific IgE was confirmed by peptide ELISA. These mimotopes could be divided into seven clusters based on sequence homology, and epitope mapping by EpiSearch of the clustered mimotopes was performed to characterize and confirm the validity of mimotopes. Five out of six of the predicted epitopes were found to overlap with previously identified epitopes of tropomyosin. To further confirm the mimicry potential of mimotopes, BALB/c mice were immunized with mimotopes conjugated to keyhole limpet hemocyanin and assayed for their capacity to induce tropomyosin-specific antibodies. BALB/c mice that received mimotope immunization were found to have an elevated level of tropomyosin-specific immunoglobulin G, but not mice that received an irrelevant mimotope. This study pioneers the successful application of the OBOC libraries using whole sera to screen and identify multiple shrimp allergen mimotopes and validates their mimicry potential using in vitro, in vivo, and in silico methods.Cellular & Molecular Immunology advance online publication, 14 september 2015; doi:10.1038/cmi.2015.83.

Tropomyosins in mosquito and house dust mite cross‐react at the humoral and cellular level

“…11 The molecular aspects of allergenic cross-reactivity among the different tropomyosins have been studied. These regions coincided with five IgE-binding mimotopes described by Leung et al 18 T-cell epitopes from shrimp and cockroach tropomyosins restricted to multiple MHC class II alleles have also been described. These regions coincided with five IgE-binding mimotopes described by Leung et al 18 T-cell epitopes from shrimp and cockroach tropomyosins restricted to multiple MHC class II alleles have also been described.…”

“…Ayuso et al 16,17 described eight peptides which correspond to five putative cross-reactive IgE-binding epitopes sharing 56%-98% of homology with tropomyosins from shrimp, lobster, HDM and cockroach. These regions coincided with five IgE-binding mimotopes described by Leung et al 18 T-cell epitopes from shrimp and cockroach tropomyosins restricted to multiple MHC class II alleles have also been described. 19,20 Aedes aegypti contains two variants of tropomyosin, Aed a 10.0101 and Aed a 10.0201, 8 which slightly differ in their primary structure.…”

“…The inhibition of IgE reactivity to each tropomyosin was assessed by ELISA activity of Aed a 10.02 in ELISA, these observations provided evidence that Aed a 10.01 and Der p 10 have more common epitopes than Der p 10 and Aed a 10.02. Previously, five highly conserved cross-reactive B-cell epitopes had been identified in tropomyosins from various sources [16][17][18]22,23. Our previous studies have suggested that these regions are conserved in Der p 10 and Aed a 10.01, but to a lesser extent in Aed a 10.02 8.…”

Low-Dose Allergen-Specific Immunotherapy Induces Tolerance in a Murine Model of Shrimp Allergy

“…Serum levels of rMet e 1-specific IgE, IgG 1 , and IgG 2a were measured by ELISA as previously described [16]. In brief, rMet e 1 (0.5 mg/100 mL NaHCO 3 , pH 9.6 coating buffer per well) was coated onto Maxisorp microtiter plates (Nunc, Roskilde, Denmark) and incubated for 3 h at 37°C.…”

Can alternative epitope mapping approaches increase the impact of B‐cell epitopes in food allergy diagnostics?

“…(aa [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60] and Ara h3_140 (aa 418-432), which were recognized by few allergic patients. 72 In comparison, the sensitivity and specificity of intact Ara h 2 were defined as, respectively, 60%-100% and 60%-96%, showing no advantage using these two key marker epitopes.…”