Characterization of the Blastocystis‐specific faecal IgA immune response in pigs

W. Wang, L. Cuttell, R. J. Traub, H. Owen, H. Bielefeldt‐Ohmann

Blastocystis is an intestinal protist found in many species including humans and pigs. It has a controversial pathogenesis and has been implicated as a potential cause of irritable bowel syndrome. Our previous studies identified pigs as potential animal models for blastocystosis by demonstrating that they were likely natural hosts of Blastocystis and can harbour subtypes (ST) in common with humans. Furthermore our finding of a lack of intestinal histopathology associated with Blastocystis infection in pigs is also a consistent finding in examined infected humans. In this study we aimed to identify and characterise the Blastocystis-specific mucosal IgA response in pigs by immunoblotting, using pig faecal antibodies and Blastocystis antigen. Faeces from 233 pigs representing three age groups (sows/boars, growers/weaners, piglets) and including five dexamethasone-immunosuppressed research pigs were tested. The majority (81.5%) of the pigs had faecal IgA reactivity against Blastocystis proteins of molecular weights of 17.5 to 120kDa. Reactivity to a >250kDa protein was found in 18.5% of pigs. Notably, immunosuppressed pigs and piglets were statistically more likely to have reactivity to this protein compared to growers/weaners and sows/boars respectively. These results corroborate other findings suggesting that compromised immunity may predispose to blastocystosis and support our contention that pigs are potentially good models for pathogenesis studies. This article is protected by copyright. All rights reserved.