Plasmid-based vaccination with candidate anthrax vaccine antigens induces durable type 1 and type 2 T-helper immune responses.

The current anthrax vaccine imparts protective immunity by generating a humoral immune response against a single antigen, the PA exotoxin subunit. While this response neutralizes the two anthrax exotoxins and protects the recipient from toxin-related mortality, the recipient is not protected from spore germination, infection, and/or bacteremia. Moreover, protective immunity against PA must be generated via a lengthy injection schedule and maintained by a yearly booster.

A retrogen plasmid-based vaccine generates high titer antibody responses against the autologous cancer antigen survivin and demonstrates anti-tumor efficacy.

We describe the use of retrogen plasmid-based vaccine technology to break tolerance and to generate a robust, dose-dependent antibody response against the self cancer antigen, survivin. We further demonstrate that this phenomenon is due to the incorporation of the survivin antigen into the retrogen system rather than to some peculiarity unique to survivin. In contrast to other genetic immunization methods designed to produce antibody responses, the retrogen system results in a broad range of antibody isotypes, indicative of both a Th-1 and a Th-2 CD4+ response.