A novelO-linked glycan modulatesCampylobacter jejunimajor outer membrane protein-mediated adhesion to human histo-blood group antigens and chicken colonization

Shaun A Cawthraw,Tim Self,Natalie Colborne,Thomas Borén,Karl G Wooldridge,Akhmed Aslam,Jafar Mahdavi,Dlawer A A Ala'Aldeen,Jeroen Stoof,Necmettin Pirinccioglu,Neil J Oldfield,Carina Sihlbom,Liljana Petrovska,Elisabet Carlsohn

doi:10.1098/rsob.130202

Abstract

Campylobacter jejuni is an important cause of human foodborne gastroenteritis; strategies to prevent infection are hampered by a poor understanding of the complex interactions between host and pathogen. Previous work showed that C. jejuni could bind human histo-blood group antigens (BgAgs) in vitro and that BgAgs could inhibit the binding of C. jejuni to human intestinal mucosa ex vivo. Here, the major flagella subunit protein (FlaA) and the major outer membrane protein (MOMP) were identified as BgAg-binding adhesins in C. jejuni NCTC11168. Significantly, the MOMP was shown to be O-glycosylated at Thr268; previously only flagellin proteins were known to be O-glycosylated in C. jejuni. Substitution of MOMP Thr268 led to significantly reduced binding to BgAgs. The O-glycan moiety was characterized as Gal(β1–3)-GalNAc(β1–4)-GalNAc(β1–4)-GalNAcα1-Thr268; modelling suggested that O-glycosylation has a notable effect on the conformation of MOMP and this modulates BgAg-binding capacity. Glycosylation of MOMP at Thr268 promoted cell-to-cell binding, biofilm formation and adhesion to Caco-2 cells, and was required for the optimal colonization of chickens by C. jejuni, confirming the significance of this O-glycosylation in pathogenesis.

Highlights

Campylobacter jejuni is the most common causative agent of bacterial gastroenteritis reported worldwide [1]
We show that flagellins are not the only O-glycosylated proteins in C. jejuni; major outer membrane protein (MOMP) is O-glycosylated, a modification that influences the MOMP conformation and blood group antigens (BgAgs) interactions
Campylobacter jejuni binds a wide range of human histo-BgAgs

Summary

Introduction

Campylobacter jejuni is the most common causative agent of bacterial gastroenteritis reported worldwide [1]. It is responsible for a spectrum of intestinal symptoms, including watery diarrhoea, bloody diarrhoea, vomiting, fever and abdominal cramps. Acute-phase disease is sometimes followed by serious long-term sequelae, including reactive arthritis [3,4], the autoimmune neuropathies Guillain–Barresyndrome (GBS) and Miller–Fisher syndrome [5] and immunoproliferative small intestinal disease [6]. The biochemical structures of gangliosides play a crucial role in the pathogenesis of GBS. Infection with C. jejuni is responsible for 35% of all types of GBS and 20–30% of GBS-linked antibodies are directed against gangliosides [7]

Methods

Results

Discussion

Conclusion