A Novel, Orally Delivered Antibody Therapy and Its Potential to Prevent Infection in Pre-clinical Models.

infection (CDI) is a toxin-mediated infection in the gut and a major burden on healthcare facilities worldwide. We rationalized that it would be beneficial to design an antibody therapy that is delivered to, and is active at the site of toxin production, rather than neutralizing the circulating and luminal toxins after significant damage of the layers of the intestines has occurred. Here we describe a highly potent therapeutic, OraCAb, with high antibody titers and a formulation that protects the antibodies from digestion/inactivation in the gastrointestinal tract.

The structure of the S-layer of Clostridium difficile.

The nosocomially acquired pathogen Clostridium difficile is the primary causative agent of antibiotic associated diarrhoea and causes tens of thousands of deaths globally each year. C. difficile presents a paracrystalline protein array on the surface of the cell known as an S-layer.

The molecular structure of the glycoside hydrolase domain of Cwp19 from Clostridium difficile.

Unlabelled: Clostridium difficile is a burden to healthcare systems around the world, causing tens of thousands of deaths annually. The S-layer of the bacterium, a layer of protein found of the surface of cells, has received a significant amount of attention over the past two decades as a potential target to combat the growing threat presented by C. difficile infections.

Functional significance of active site residues in the enzymatic component of the binary toxin.

binary toxin (CDT) is an ADP-ribosyltransferase which is linked to enhanced pathogenesis of strains. CDT has dual function: domain (CDTa) catalyses the ADP-ribosylation of actin (enzymatic component), whereas domain (CDTb) transports CDTa into the cytosol (transport component). Understanding the molecular mechanism of CDT is necessary to assess its role in infection.

Cwp2 from Clostridium difficile exhibits an extended three domain fold and cell adhesion in vitro.

Unlabelled: Colonization of the gut by Clostridium difficile requires the adhesion of the bacterium to host cells. A range of cell surface located factors have been linked to adhesion including the S-layer protein LMW SLP and the related protein Cwp66. As well as these proteins, the S-layer of C.

Molecular features of the sortase enzyme family.

Bacteria possess complex and varying cell walls with many surface exposed proteins. Sortases are responsible for the covalent attachment of specific proteins to the peptidoglycan of the cell wall of Gram-positive bacteria. Sortase A of Staphylococcus aureus, which is seen as the archetypal sortase, has been shown to be essential for pathogenesis and has therefore received much attention as a potential target for novel therapeutics.

Structure and function of a Clostridium difficile sortase enzyme.

Sortase enzymes are responsible for covalent anchoring of specific proteins to the peptidoglycan of the cell wall of gram-positive bacteria. In some gram-positive bacteria (e.g.

Cwp84, a Clostridium difficile cysteine protease, exhibits conformational flexibility in the absence of its propeptide.

In recent decades, the global healthcare problems caused by Clostridium difficile have increased at an alarming rate. A greater understanding of this antibiotic-resistant bacterium, particularly with respect to how it interacts with the host, is required for the development of novel strategies for fighting C. difficile infections.

The structure of the cysteine protease and lectin-like domains of Cwp84, a surface layer-associated protein from Clostridium difficile.

Clostridium difficile is a major problem as an aetiological agent for antibiotic-associated diarrhoea. The mechanism by which the bacterium colonizes the gut during infection is poorly understood, but undoubtedly involves a myriad of components present on the bacterial surface. The mechanism of C.

Expression, purification, crystallization and preliminary crystallographic analysis of a putative Clostridium difficile surface protein Cwp19.

Cwp19 is a putatively surface-located protein from Clostridium difficile. A recombinant N-terminal protein (residues 27-401) lacking the signal peptide and the C-terminal cell-wall-binding repeats (PFam04122) was crystallized using the sitting-drop vapour-diffusion method and diffracted to 2 Å resolution. The crystal appeared to belong to the primitive monoclinic space group P2(1), with unit-cell parameters a=109.

Super toxins from a super bug: structure and function of Clostridium difficile toxins.

Clostridium difficile, a highly infectious bacterium, is the leading cause of antibiotic-associated pseudomembranous colitis. In 2009, the number of death certificates mentioning C. difficile infection in the U.

Expression, purification and cell cytotoxicity of actin-modifying binary toxin from Clostridium difficile.

Clostridium difficile infection (CDI) is a serious problem within the healthcare environment where the bacterium causes symptoms ranging from mild diarrhoea to life-threatening colitis. In addition to its principal virulence factors, Toxin A and Toxin B, some C. difficile strains produce a binary toxin (CDT) composed of two sub-units namely CDTa and CDTb that are produced and secreted from the cell as two separate polypeptides.

Cwp84, a surface-associated cysteine protease, plays a role in the maturation of the surface layer of Clostridium difficile.

Clostridium difficile is a major and growing problem as a hospital-associated infection that can cause severe, recurrent diarrhea. The mechanism by which the bacterium colonizes the gut during infection is poorly understood but undoubtedly involves protein components within the surface layer (S-layer), which play a role in adhesion. In C.

Structural basis for substrate recognition in the enzymatic component of ADP-ribosyltransferase toxin CDTa from Clostridium difficile.

ADP-ribosylation is one of the favored modes of cell intoxication employed by several bacteria. Clostridium difficile is recognized to be an important nosocomial pathogen associated with considerable morbidity and attributable mortality. Along with its two well known toxins, Toxin A and Toxin B, it produces an ADP-ribosylating toxin that targets monomeric actin of the target cell.