Characterization and immunogenicity analysis of glutathi- one S-transferase from Otodectes cynotis.

Otodectes cynotis (ear mite), the primary etiological agent of feline otitis externa, represents a significant veterinary concern due to its high prevalence and treatment challenges. Glutathione S-transferase (GST), a detoxifying and immunogenic enzyme in various parasites, is a potential molecular target for vaccine development. In this study, we cloned and heterologously expressed the GST gene from O. cynotis, confirmed its recombinant protein activity using 1-chloro-2,4-dinitrobenzene (CDNB) as a substrate, and determined its optimal enzymatic conditions (pH 8, 30 °C). Bioinformatic analysis revealed high sequence conservation with arthropod homologs, predicted functional domains, and identified several immunogenic B- and T-cell epitopes. Molecular docking with ethacrynic acid indicated stable binding, suggesting GST as a potential drug target. This study presents the first functional and immunogenic characterization of O. cynotis GST, suggesting its critical role in oxidative stress mitigation and drug detoxification, and supporting its potential as an anti-mite vaccine candidate.