Allergenic Characterization of 27-kDa Glycoprotein, a Novel Heat Stable Allergen, from the Pupa of Silkworm, Bombyx mori

Abstract

Boiled silkworm pupa is a traditional food in Asia, and patients with silkworm pupa food allergy are common in these regions. Still now only one allergen from silkworm, arginine kinase, has been identified. The purpose of this study was to identify novel food allergens in silkworm pupa by analyzing a protein extract after heat treatment. Heat treated extracts were examined by proteomic analysis. A 27-kDa glycoprotein was identified, expressed in Escherichia coli, and purified. IgE reactivity of the recombinant protein was investigated by ELISA. High molecular weight proteins (above 100 kDa) elicited increased IgE binding after heat treatment compared to that before heat treatment. The molecular identities of these proteins, however, could not be determined. IgE reactivity toward a 27-kDa glycoprotein was also increased after heating the protein extract. The recombinant protein was recognized by IgE antibodies from allergic subjects (33.3%). Glycation or aggregation of protein by heating may create new IgE binding epitopes. Heat stable allergens are shown to be important in silkworm allergy. Sensitization to the 27-kDa glycoprotein from silkworm may contribute to elevation of IgE to silkworm.

Allergic risks of consuming edible insects: A systematic review

“…Of these 25 articles, 8 studied the cross-reactivity/cosensitisation between edible insects, crustaceans and HDM [35][36][37][38][39][40][41][42], 3 identified and characterized allergens of edible insects [43][44][45], 10 were cases reports or case series of food allergy caused by insects (8 case reports [46][47][48][49][50][51][52][53], and 2 case series [54,55]), 3 assessed the frequency of anaphylaxis caused by entomophagy [56][57][58] and 1 assessed the prevalence of allergy among insect-eaters [59].…”

Baculoviral infection reduces the expression of four allergen proteins of silkworm pupa

“…Notably, of the 36 proteins identified in the present study, the mRNA and protein expression of Jafrac1, p27k, arginine kinase, and paramyosin, which are the four known allergens, were significantly downregulated. Studies have shown that the four proteins can induce an IgE‐mediated allergic response in patients (García‐Orozco, Aispuro‐Hernández, Yepiz‐Plascencia, Calderón‐de‐la‐Barca, & Sotelo‐Mundo, ; Jeong et al, ; H. Wang et al, ; Zhao, Li, Kuang, Luo, & Li, ). Moreover, p27k and arginine kinase are thermostable, and thus, their allergenicity cannot be destroyed by heating (García‐Orozco et al, ; Jeong et al, ).…”

“…Studies have shown that the four proteins can induce an IgE‐mediated allergic response in patients (García‐Orozco, Aispuro‐Hernández, Yepiz‐Plascencia, Calderón‐de‐la‐Barca, & Sotelo‐Mundo, ; Jeong et al, ; H. Wang et al, ; Zhao, Li, Kuang, Luo, & Li, ). Moreover, p27k and arginine kinase are thermostable, and thus, their allergenicity cannot be destroyed by heating (García‐Orozco et al, ; Jeong et al, ). Madero et al () showed that the 27‐kDa hemolymph protein of Galleria mellonella , an airborne allergen, shares 54.9% amino acid similarity with p27k of the silkworm, further highlighting its allergenicity.…”

“…However, beyond this characterization and after localization studies in other species, very little is known about this protein. Though p27k appears to be a stable allergen (Jeong et al, ; Madero et al, ), additional studies are necessary to understand the mechanism underlying these effects.…”

“…However, many silkworm pupal proteins including arginine kinase (Binder et al, ), thiol peroxiredoxin (H. Wang, Hu, & Liang, ), and p27k, a putative cuticle protein (Jeong et al, ) can cause allergic reactions in some patients. In India, silk‐related occupations rank the highest with regard to occupational asthma development and incidence (Harindranath, Prakash, & Subba Rao, ).…”