A newly identified antibody capable of neutralizing the inhalation anthrax toxin in rabbits and monkeys may offer an alternative method of preventing and treating infection in humans say US researchers. Their findings appear in the October 2006 issue of the journal Infection and Immunity.
The intentional use of Bacillus anthracis, the causative agent of anthrax, continues to pose serious threat as a bioterrorism or biowarfare agent. Although vaccines currently available are highly effective, multiple doses are required therefore necessitating antibiotic therapy for those individuals exposed prior to scheduled completion.
Monoclonal antibodies (MAb) are derived from one clone of cells, recognize only one antigen (the protective antigen (PA) component of the anthrax toxin combines with the lethal factor for cell entry) and are described as highly specific and purified. In the study the fully human MAb (now recognized at MAb 1303) was selected after neutralizing the anthrax toxin in transgenic mice. MAb 1303 was then found to offer effective postsymptomatic treatment in rabbits exposed to aerosolized anthrax spores as well as serve as a protective agent in monkeys challenged with aerosolized anthrax spores following a single intramuscular injection.
"Selection of an anti-PA MAb by using a functional assay that is a surrogate for protection has resulted in the identification of a fully human MAb with potent activity in vivo and uncovered a previously unrecognized mechanism of antibody-mediated toxin neutralization that is important for currently used anthrax vaccines," say the researchers.
(L. Vitale, D. Blanset, I. Lowy, T. O'Neill, J. Goldstein, S.F. Little, G.P. Andrews, G. Dorough, R.K. Taylor, T. Keler. 2006. Prophylaxis and therapy of inhalational anthrax by a novel monoclonal antibody to protective antigen that mimics vaccine-induced immunity. Infection and Immunity, 74.10: 5840-5847.)
Materials provided by American Society For Microbiology. Note: Content may be edited for style and length.
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