Clostridium difficile is a widespread bacterium and it affects thousands of patients, posing a danger to their health and life. The costs associated with treatment are estimated at 10 to 20 billion dollars only in North America. Scientists from the University of Calgary at the National Research Council in Canada carried out a research on Clostridum difficile and expect success thanks to the use of antibodies from a llama.

Clostridium difficile is a Gram positive rod, forming spores and having the ability to move. This bacterium occurs commonly in the environment and is a part of animal normal gut flora. Moreover, it resides also in gut of infants and young children, without causing symptoms of disease, probably due to the lack of appropriate receptors for these bacteria. According to some sources, the presence of C. difficile can be detected even in 70% of children. In adults C. difficile is the cause of pseudomembranous colitis, whose symptoms are diarrhea (sometimes with an admixture of blood), abdominal pain and fever. More severe symptoms can lead to dehydration and shock or even death. These bacteria are naturally resistant to many antibiotics, therefore, medicines of first choice are metronidazole and vancomycin. Metronidazole is administered orally, and although it is absorbed in the first part of digestive tract, usually is effective. Vancomycin is applied parenterally. Unfortunately, the resistance among different strains of C. difficile grows, also against these antibiotics. Therefore, an alternative treatment of infections is being searched.

Scientists from the University of Calgary discovered that simple antibody can neutralize toxins secreted by C. difficile. Publication concerning this news appeared on 18 March in the Journal of Biological Chemistry. It is estimated that approximately 2% of hospitalized patients are resided with those rods which begin to overrun the colon after disturbance of intestines homeostasis. Chronically sick patients are unable to cope with the infection, even with the aid of drugs. C. difficile produces two types of toxins – A and B, which damage cells in the intestines by binding to the glycoproteins placed on the surface, preventing the proper functioning of the cell. However, it was possible to obtain an antibody abolishing their harmful effects. Llama came with help.

LLamas produce antibodies similar to the human ones, but in their serum there are also antibodies of a very simple construction, made only from one domain. They are up to 10-times smaller than other antibodies. Thanks to this property they can be easily isolated and modified in any way and after that they can be tested in many studies. Specially prepared antibodies can be used as a medicament. Currently they are being used in the experiments with C. difficile. It appeared that llama antibodies neutralize the toxins produced by the rods, but the exact mechanism of this action is not yet fully understood. This is the stage for further research of the scientists who use these antibodies as medication in pseudomembranous colitis. In addition, simultaneously new studies are being carried out to use the same antibodies in other infectious diseases.

Author: MD, PhD Karolina Kłoda

Source:
1. G. Hussack, M. Arbabi-Ghahroudi, H. van Faassen, J. G. Songer, K. K.- S. Ng, R. MacKenzie, J. Tanha. Neutralization of Clostridium difficile Toxin A with Single-domain Antibodies Targeting the Cell Receptor Binding Domain. Journal of Biological Chemistry, 2011; 286 (11): 8961 DOI: 10.1074/jbc.M110.198754.
2. University of Calgary (2011, March 18). Hospital infections: Unique antibody from llamas provide weapon against Clostridium difficile. ScienceDaily. Retrieved March 19, 2011, from http://www.sciencedaily.com­ /releases/2011/03/110318111927.htm.
3. http://en.wikipedia.org/wiki/Clostridium_difficile