Saturday, 14 December 2013

Insight into anthrax infection


An anthrax infection can be fatal even when the infectious agent is no longer detected. Research carried out at EPFL reveals the way its lethal factor manages to turn invisible to the immune system.

The bacterium responsible for anthrax develops a strategy reminiscent of the Trojan horse tale. Its pathogenic factor is able to penetrate inside a cell in such a way that it becomes completely invisible to both the immune system and medical analysis. Furthermore, it manages to exit the cell several days later, and then it continues to poison other cells.

In a new study, researchers focused in the way the anthrax toxin was able to get inside the cell. Composed of two elements -- a "protective antigen" and a "lethal factor," the toxin does not merely create a passage across the cellular membrane. Instead, it introduces itself by endocytosis, a process by means of which the pathogen is "swallowed" by the cell. Once inside the cell, anthrax's lethal factor is sheltered by the cell's membrane, forming an "endosome," in which it can wait for several days. Then, it can either be released inside the cell, causing it to malfunction, or it can be released towards the external environment inside small vesicles -- called exosomes -- and get into another cell.

For further details, refer to the following paper:

Laurence Abrami, Lucia Brandi, Mahtab Moayeri, Michael J. Brown, Bryan A. Krantz, Stephen H. Leppla, F. Gisou van der Goot. Hijacking Multivesicular Bodies Enables Long-Term and Exosome-Mediated Long-Distance Action of Anthrax Toxin. Cell Reports, 2013; DOI: 10.1016/j.celrep.2013.10.019

Posted by Tim Sandle