A newly identified inhibitor of the anthrax toxin may be used to develop a safer and more effective vaccine and act as a therapeutic agent after exposure say researchers from Massachusetts and Germany. Their findings appear in the June 2005 issue of the journal Infection and Immunity.
Anthrax is a highly contagious and toxic disease that results from infection with the bacterium Bacillus anthracis. If not caught immediately, those infected may die within a matter of days. Anthrax poses a deadly threat as a potential biological weapon placing added emphasis on the need for a safe and effective vaccine. The vaccine currently available doesn't protect against the bacilli and may be hazardous to its host when used immediately after exposure.
In the study researchers infected two groups of mice with anthrax and immunized one group with a dominant-negative inhibitor (DNI) and the other with a protective antigen (PA) currently used in the anthrax vaccine. They monitored the mice for several weeks and found that DNI alone produced higher immune responses than PA. Due to DNI's ability to inhibit the anthrax toxin, researchers also believe that DNI-based vaccines may increase immunity and provide therapeutic activity when administered postexposure.
"The strong immunogenicity and retained antigenicity of DNI suggest that DNI is a promising and potentially safer candidate for use in an anthrax vaccine than PA," say the researchers. "Moreover, in the event of anthrax infection, the administration of DNI can serve not only as an antitoxic therapy as an immediate response but also as a prophylactic vaccine to prevent late-onset or future anthrax infection."
(B.A. Aulinger, M.H. Roehrl, J.J. Mekalanos, R.J. Collier, J.Y. Wang. 2005. Combining anthrax vaccine and therapy: a dominant-negative inhibitor of anthrax toxin
Contact: Carrie Patterson
American Society for Microbiology