Application of a gut-immune co-culture system for the study of N-glycan-dependent host-pathogen interactions of Campylobacter jejuni

An in vitro gut-immune co-culture model with apical and basal accessibility, designed to more closely resemble a human intestinal microenvironment, was employed to study the role of the Nlinked protein glycosylation (Pgl) pathway in Campylobacter jejuni pathogenicity. The gutimmune co-culture (GIC) was developed to model important aspects of the human small intestine by the inclusion of mucin producing goblet cells, human enterocytes, and dendritic cells, bringing together a mucus-containing epithelial monolayer with elements of the innate immune system. The utility of the system was demonstrated by characterizing host-pathogen interactions facilitated by N-linked glycosylation, such as host epithelial barrier functions, bacterial invasion and immunogenicity. Changes in human intestinal barrier functions in the presence of 11168 C. jejuni (wildtype) strains were quantified using GICs. The glycosylationdeficient strain 11168 {Delta}pglE was 100-fold less capable of adhering to and invading this intestinal model in cell infectivity assays. Quantification of inflammatory signaling revealed that 11168{Delta}pglE differentially modulated inflammatory responses in different intestinal microenvironments, suppressive in some but activating in others. Virulence-associated outer membrane vesicles produced by wildtype and 11168{Delta}pglE C. jejuni were shown to have differential composition and function, with both leading to immune system activation when provided to the gut-immune co-culture model. This analysis of aspects of C. jejuni infectivity in the presence and absence of its N-linked glycome, is enabled by application of the gut-immune model and we anticipate that this system will be applicable to further studies of C. jejuni and other enteropathogens of interest.