Immunological properties of surface proteins of Clostridium difficile

Abstract

Sera from patients with Clostridium difficile-associated disease (CDAD) and sera from a control group were analysed by an ELISA to detect antibodies directed against four surface proteins and toxins A and B of C. difficile. The surface proteins were the flagellar cap protein FliD, the flagellin FliC, the adhesin Cwp66 divided into two domains, Cwp66-Nterminal and Cwp66-Cterminal, and the fibronectin-binding protein Fbp68. For each antigen, antibody levels in the CDAD patient group and in the control group were compared. In the CDAD patient group, the mean of the antibody levels decreased from Cwp66-Cterminal to Fbp68, FliD, toxins B and A, Cwp66-Nterminal and finally FliC, suggesting different immunogenic properties among these adhesins. For Cwp66-Nterminal, FliC, FliD and Fbp68, the antibody level observed in the control group was higher than in the CDAD group with a statistically significant difference whereas the antibody level for toxins A and B was not statistically different. In conclusion, this study suggests that during the clinical course of disease, C. difficile adhesins are able to induce an immune response which could play a role in the defence mechanism of the host.

The host immune response to Clostridium difficile infection

“…The intestinal epithelium is also able to sense other C. difficile proteins, including SLPs, cell-wall proteins Cwp66 and Cwp84 and flagellin via specific cell surface toll-like receptors (TLRs) including TLR4 and TLR5 [Jarchum et al 2011;Ryan et al 2011]. Once the protective epithelial barrier has been breached, TcdA, TcdB and other C. difficile proteins come into contact with submucosal macrophages, monocytes and dentritic cells and trigger dissemination of the inflammatory cascade via further release of proinflammatory cytokines IL-1a, IL-1b, IL-6, IL-8 and tumour necrosis factor-a [Linevsky et al 1997;Pothoulakis, 1996;Flegel et al 1991;MeloFilho et al 1997;Bianco et al 2011;Pechine et al 2005a;Ryan et al 2011;Vohra and Poxton, 2012].…”

“…Immunoglobulin G A high IgG response to C. difficile toxins and surface proteins at the time of colonization is thought to protect against development of CDI [Pechine et al 2005a;Kyne et al 2000;Mulligan et al 1993]. Once a patient has developed symptomatic CDI, serum IgG responses to TcdA, B and nontoxin antigens on day 12 post onset of diarrhoea have been shown to be higher in patients who experience a single episode of CDI compared with patients with recurrent CDI [Kyne et al 2001].…”

A real-time quantitative PCR assay for evaluating Clostridium difficile adherence to differentiated intestinal Caco-2 cells

“…Moreover, the flagellar proteins FliC (flagellin) and FliD (flagellar cap protein) bind to axenic mouse mucus possibly facilitating the initial penetration of the intestinal mucus layer (Tasteyre et al, 2001). CDI patients are known to produce serum antibodies to one or more of these cellsurface proteins during infection, emphasizing their potential role in pathogenesis and generating a protective host immune response (Pechine et al, 2005;Wright et al, 2008).…”

“…Moreover, the flagellar proteins FliC (flagellin) and FliD (flagellar cap protein) bind to axenic mouse mucus possibly facilitating the initial penetration of the intestinal mucus layer (Tasteyre et al, 2001). CDI patients are known to produce serum antibodies to one or more of these cellsurface proteins during infection, emphasizing their potential role in pathogenesis and generating a protective host immune response (Pechine et al, 2005;Wright et al, 2008).Several in vitro C. difficile adherence assays have been described (Cerquetti et al, 2002;Drudy et al, 2001;Eveillard et al, 1993; Waligora et al, 1999). There is, however, a lack of standardization in these C. difficile adhesion protocols with respect to the type and state of confluency of the tissue culture cells employed in addition to the duration and atmospheric conditions of the assays.…”

New and emerging therapies for Clostridium difficile infection

“…48 Ideally, C. difficile vaccines could include targets that reduce primary colonisation as well as toxin neutralisation. A key issue for trials is which subjects will best benefit from vaccination.…”