Oral Vaccine Containing Salmonella May Protect Against Aerosolized Anthrax

Anthrax is a deadly disease that affects wildlife, livestock and humans and presents a serious threat as a potential biological weapon. Currently, there is a vaccine licensed for use in the US and the United Kingdom, and although effective, it requires multiple injections over several months, is expensive to produce and is only available to military personnel. A safe, effective and long-lasting vaccine available to civilians is necessary to protect mass populations in the event of an attack.

In the study researchers produced Salmonella enterica serovar Typhimurium expressing differing levels of the necessary protective antigen to induce anthrax immunity and orally immunized groups of mice. Following immunization the mice were then challenged with aerosolized anthrax spores. Five of the six mice that received the vaccine containing full expression of the antigen were protected against infection, while the vaccine with reduced antigen levels only provided up to 25 % protection.

"In the present study, we have shown for the first time that orally administered Salmonella expressing PA is able to protect mice against infection caused by airborne B. anthracis," say the researchers.

(M.G.M. Stokes, R.W. Titball, B.N. Neeson, J.E. Galen, N.J. Walker, A.J. Stagg, D.C. Jenner, J.E. Thwaite, J.P. Nataro, L.W.J. Baillie, H.S. Atkins. 2007. Oral administration of a Salmonella enterica-based vaccine expressing Bacillus anthracis protective antigen confers protection against aerosolized B. anthracis. Infection and Immunity, 75. 4: 1827-1834).