For example, C. jejuni adhesion to Caco-2 cell receptors was inhibited by certain lectins [9]. Campylobacter is capable of producing a variety of glycoproteins, some of which are

cell-surface Protein Tyrosine Kinase inhibitor located [10]. Inactivation of the N-linked glycosylation system reduces bacterial ability to adhere to epithelial cells and thereby colonise the gastrointestinal tract [11, 12]. These findings suggest a possible role of some bacterial cell surface surface-located bacterial N-linked glycoproteins in interaction with host cell receptors. Van Sorge and colleagues [13] demonstrated interaction of N-linked glycoproteins of C. jejuni with C-type lectins of Macrophage Galactose-type lectins (MGL). In similarity with other pathogens, the production of cell surface structures interacting with C-type lectins may assist C. jejuni in the evasion of the host immune response [14, 15]. Another cell surface structure that may affect bacterial interaction with host cell receptors is a capsular polysaccharide (CPS) [16–19]. Inactivation of the capsule production machinery in strain 81–176 led to a two-fold decrease in adhesion to INT407 cells [20]. Similar findings were observed in another capsule Z-VAD-FMK cell line deficient mutant, 81116/kpsE[21].

However, these data were not supported by complementation studies. Moreover, they are in disagreement with other studies where the absence of capsule showed increased adhesion of C. jejuni strain 11168H to Caco-2 cells [16]. The contradictory results may be a consequence of differences in assay conditions, bacterial strains and tissue cell lines. In general, the capsules may play different roles in bacterial

attachment. This depends on the nature of a bacterial pathogen, and on the structural features of the capsules and adhesins. For example, F1 capsule of a Yersinia pestis prevents fimbrial CYTH4 adhesins from interaction with host cell receptors [22], while production of a capsule by Neisseria meningitidis does not affect PilC1 adhesin-mediated bacterial attachment [23]. In this study we developed and evaluated an in vitro ELISA-like assay for the investigation of C. jejuni interaction with host cell receptors. The assay was successfully used to study a role of capsule in attachment using SBA (Soya bean agglutinin) lectin as an analogue of a host cell receptor. In addition, using targeted mutagenesis (supported by complementation analysis) we investigated a role of PEB3 and JlpA adhesins in this interaction. Furthermore, using real time PCR, we found that peb3 and a capsule-related gene are differentially expressed. The results of these experiments suggest an interplay between bacterial capsule and adhesins in interaction with host cells. Results Dose-dependent specific binding of C. jejuni cells to immobilised SBA lectin In order to investigate the mechanisms and factors involved in C.