List Biological Laboratories, Inc. is pleased to announce a key addition to our Clostridium difficile Toxin A and Toxin B product line. Our new product, 155L is a liquid formulation of Toxin B. This product allows for the highest activity level of any of our C.difficile offerings and the most stability.  It already shows stability for several months when stored at 2-8°C and we will continue to update.

This product is offered in a 50 µg size for $450.

We are very excited about the liquid formulation and the flexibility it will allow in the lab. It is now available from stock, and ships on Blue Ice throughout the U.S. and Canada and worldwide with special arrangements.

Clostridium difficile Toxin A
We have enjoyed tremendous success with our Toxin A. We have determined that the best activity and stability post-reconstitution (up to 2 months) is in the 100 µg size, #152C. The price for this product has been lowered from $535 to $300 based on the dramatic improvements in our yield and the substantial growth in overall sales. We are happy to pass this savings on, making it a terrific value for our C.difficile customers.

Clostridium difficile Toxin B
Products 155A and 155B have a newly formulated buffer which allows for highly active Toxin B. After reconstitution, this product is stabile for days when stored at 2-8°C and is now available from stock.

Related Products
We offer a variety of Binary Toxins and Antibodies to complement your C.difficile research. We have Binary Toxins, both A and B subunit. Check our website for more information.

Bulk Product Orders
Should you have need of a substantial quantity of C.difficile in bulk, please let us know what quantity and formulation you desire. With sufficient quantity, we can often tailor to your specific needs. We generally have bulk available for all C.difficile offerings.  We also offer other types of bulk reagents for purchase.

Coming Soon-Pipeline
Clostridium difficile produces and secretes a glutamate dehydrogenase (cdGDH). This enzyme is highly conserved among different ribotypes, and antibodies to cdGDH are often included in detection kits for C. difficile infection (CDI), increasing sensitivity. While cdGDH is available recombinantly, we have isolated and purified the cdGDH from a native strain of C. difficile. In addition to the enzyme, chicken antibodies will be generated and made available soon.

We welcome your feedback on these changes and would love to hear how the new formulations and new products work for you. Please contact us with your comments and feedback.

What is Clostridium Difficile?

Clostridium difficile is the causative agent of antibiotic-associated diarrhea and pseudomembranous colitis.  It produces two major exotoxins, Toxin A and Toxin B; however, about 10% of strains isolated from patients with colitis also contain genes, coding for a unique ADP-ribosylating toxin, CDT Binary Toxin. Additionally, Clostridium difficile produces and secretes a glutamate dehydrogenase (cdGDH).

List Labs offers four new products in the C. difficile family

New product offerings from List Labs cover other proteins produced concurrently with the exotoxins.  These proteins are valuable as alternate markers allowing more sensitive or more accurate determination of C. difficile infections (CDI).

These new products, all related to C. difficile, will be of interest to diagnostic developers, vaccine manufacturers, as well as, to those doing research in infectious diseases.  List Labs is notably offering antigens and antibodies for two C. difficile proteins which are present in C. difficile infections.  These products add to our C. difficile reagents which also include the main virulence factors Toxin A and Toxin B, and the antibodies: Goat Anti-Toxin A, Chicken Anti-Toxin B and Chicken Anti-Toxin B.

The first two products are components of CDT Binary Toxin, an ADP-ribosyltransferase.  This toxin is composed of two independently produced components, the enzymatic subunit A, CdtA, and the binding and translocation subunit B, CdtB, which mediates cell entry of CdtA.  CDT Binary Toxin causes depolymerization of the actin cytoskeleton and formation of microtubule-based membrane protrusions,resulting in cell rounding and cell death, and it is suggested to be involved in enhanced bacterial adhesion and colonization of hypervirulent C. difficile strains.  The cell surface receptor has been identified as lipolysis stimulated lipoprotein receptor (LSR).

CDT Binary Toxin, A Subunit (CDTa), Product # 157, is recombinantly expressed in E. coli and purified using affinity chromatography.  The affinity tag has subsequently been cleaved from the protein prior to packaging.  Binary toxin A subunit has been tested in an in vitro ADP-ribosylation assay.  It is non-toxic and unable to penetrate cells in the absence of the B subunit binding and translocation domain.  Expression and purification of the A subunit from a recombinant setting ensures that there is no possible contamination with the B subunit.

1)      #157A, Binary Toxin from Clostridium difficile A Subunit 20 ug, price $350

CDT Binary Toxin, B Subunit (CDTb), Product # 158, is recombinantly expressed in E. coli, purified using affinity chromatography and the affinity tag cleaved.  Prior to packaging, the B subunit is nicked with trypsin for activation.  The B subunit of the Binary Toxin is non-toxic, and does not contain any enzymatic activity.

2)      #158A, Binary Toxin from Clostridium difficile B Subunit 40 ug, price $350

 The next products are chicken antibodies: Chicken Anti-CDT Binary B subunit antibodies, with and without biotin.  Antibodies have been raised against C. difficile Binary Toxin B Subunit and affinity purified on an antigen column, Product # 758.  These antibodies are suitable for use in Western Blot assays and ELISAs as an effective probe for C. difficile Binary Toxin B Subunit.  Additionally, purified antibody has been labeled with biotin, Product # 759, providing antibodies for both capture and detection.

3)      #758A, Anti – C. difficile Binary Toxin B Subunit (Chicken IgY) 0.1 mg, price $290

4)      #759A, Biotinylated Anti – C. difficile Binary Toxin B Subunit (Chicken IgY) 0.1 mg, price $315

Usage

Use of CDT on subconfluent Caco-2 cells is described by Schwan et al, 2009.  Toxin –induced cellular processes were observed on these cells after one hour treatment with CDT Binary Toxin, a mixture of 20 ng/ml of CDTa and 40 ng/ml of CDTb.

Use our new Citations Finder to see additional citations of how C. Difficile from List Labs has been used in research.

Reference

1. Schwan C., Stecher B., Tzivelekidis T., van Ham M., Rohde M., Hardt WD., Wehland J., Aktories K., (2009) Clostridium difficile Toxin CDT Induces Formation of Microtubule-Based Protrusions and Increases Adherence of Bacteria. PLoS Pathog 5(10): e1000626. PMID: 19834554