New Insights into the Mechanism of Action of PirAB from Vibrio Parahaemolyticus

Abstract

PirAB toxins secreted by <i>Vibrio parahaemolyticus</i> (<i>Vp</i>) harbor the pVA1 virulence plasmid, which causes acute hepatopancreatic necrosis disease (AHPND), an emerging disease in Penaeid shrimp that can cause 70-100% mortality and that has resulted in great economic losses since its first appearance. The cytotoxic effect of PirAB^Vp on the epithelial cells of the shrimp hepatopancreas (Hp) has been extensively documented. New insights into the biological role of the PirB^Vp subunit show that it has lectin-like activity and recognizes mucin-like O-glycosidic structures in the shrimp Hp. The search for toxin receptors can lead to a better understanding of the infection mechanisms of the pathogen and the prevention of the host disease by blocking toxin-receptor interactions using a mimetic antagonist. There is also evidence that <i>Vp</i> AHPND changes the community structure of the microbiota in the surrounding water, resulting in a significant reduction of several bacterial taxa, especially <i>Neptuniibacter</i> spp. Considering these findings, the PirAB^vp toxin could exhibit a dual role of damaging the shrimp Hp while killing the surrounding bacteria.