Glutathione S-transferase (GST) of American Cockroach, Periplaneta americana: Classes, Isoforms, and Allergenicity

Nitat Sookrung,Anchalee Tungtrongchitr,Pongsakorn Tantilipikorn,Nitaya Indrawattana,Nawannaporn Saelim,Watee Seesuay,Wanpen Chaicumpa,Rojana Poolphol,Onrapak Reamtong,Chaweewan Bunnag

doi:10.1038/s41598-017-18759-z

Abstract

Insect glutathione S-transferases (GSTs) play important roles in insecticide/drug resistance and stress response. Medically, GSTs of house dust mites (Dermatophagoides pteronyssinus and Blomia tropicalis) and German cockroach (Blattella germanica) are human allergens. In this study, classes, isoforms and B-cell and allergenic epitopes of GST of American cockroach, Periplaneta americana, the predominant species in the tropics and subtropics were investigated for the first time. Enzymatically active native and recombinant P. americana-GSTs bound to IgE in sera of all P. americana allergic patients that were tested. By gel-based proteomics and multiple sequence alignments, the native GST comprises three isoforms of delta and sigma classes. All isoforms interacted with serum IgE of the cockroach allergic subjects. Molecularly, the protein contains six B-cell epitopes; two epitopes located at β1-α1 and β4-α3 regions bound to patients’ serum IgE, indicating that they are allergenic. P. americana are ubiquitous and their GST can sensitize humans to allergic diseases; thus, the protein should be included in the allergen array for component resolved diagnosis (CRD) of allergic patients, either by skin prick test or specific IgE determination. The GST is suitable also as a target of environmental allergen detection and quantification for intervention of cockroach sensitization and allergic morbidity.

Highlights

Negative to all allergens tested Negative to all allergens tested Negative to all allergens tested Negative to all allergens tested Negative to all allergens tested
Gene sequence coding for full-length P. americana-Glutathione S-transferases (GSTs) (648 bp) was cloned into pKRX-T cloning vector and subcloned into pET20b+ protein expression vector
Glutathione S-transferases (GSTs) are indispensable enzymes which insects use to protect themselves against oxidative damage and stress and insecticide toxicity[30]

Summary

Introduction

All insect GSTs are cytosolic and further subdivided into at least six classes including delta, epsilon, omega, sigma, theta, and zeta, based on phylogenetic analysis[23]. It was reported that increased levels of GST activity contributed to increase detoxification capacity and resistance of the insects to several insecticides[28,29,30,31]. GST of many organisms have been reported as human allergens including Dermatophagoides pteronyssinus (Der p 8)[32,33], Bromia tropicalis (Blo t 8)[34], Blattella germanica or German CR (Bla g 5)[35], Alternaria alternata[36], Ascaris lumbricoides and Ascaris suis (Asc s 1 and Asc s 3)[34,37]. The B. germanica GSTs, i.e., sigma BgGSTS1 and delta BgGSTD1 have been reported as potent human allergens[35,38]. In this study, P. americana GST classes, isoforms, allergenicity, and B cell epitopes were investigated

Methods

Results

Conclusion