DNA vaccines against enteric infections.

The first DNA vaccines for prevention of infectious diseases were described in 1993 and have since been shown to generate protective humoral and cellular immune responses to numerous infectious agents. For enteric infections, protective immunity has been obtained with DNA vaccines against several enteric viral, bacterial, and parasitic agents. Inoculation of DNA vaccines has generally been by intramuscular injection or by gene gun delivery of vaccine DNA-coated gold microparticles into the skin. Administration of DNA vaccines by the oral route would target the vaccines to enteric mucosal tissues, as well as providing a convenient means for vaccine delivery. Orally administered plasmid DNAs encapsulated in polymeric microparticles or inserted in live bacterial vectors have been effective in animal models for rotavirus DNA vaccines and Listeria monocytogenes DNA vaccines, respectively. Human trials of enteric DNA vaccines have not been initiated, but trials of veterinary vaccines have shown promise.