DNA Vaccine Protects Against Anthrax

"The naked DNA approach is vaccination at its simplest. The gene encoding the vaccine is introduced into the host and expressed in vivo where it stimulates a protective immune response," says Matthew Bell, of the Ohio State University, one of the researchers on the study.

Having previously shown the effectiveness of a DNA vaccine in mice, Bell and his colleagues tested the vaccine on a higher form of mammal: rabbits. The animals were given a vaccine made of DNA that coded for either the lethal factor (LF) or the protective antigen (PA) component of the anthrax toxin in order to stimulate the immune system to produce antibodies against those compounds. The researchers tested the ability of the vaccine to both stimulate antibody production and protect against lethal infection. While the LF-based DNA vaccine appeared to stimulate higher levels of antibodies, only 56% of the rabbits survived an aerosolized spore challenge. In contrast all of the rabbits given the PA-based DNA vaccine survived.

"Although LF stimulates higher antibody titers than PA, immunization with PA induces antibodies that are more capable of neutralizing toxin and conferring protection," says Bell.

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