Pre-priming: a novel approach to DNA-based vaccination and immunomodulation.

Abstract

The increasing prevalence of allergic diseases, a rise in microbial resistance, and new and emerging pathogens represent major health threats as we enter the new millennium. Traditional protein-based immunotherapy and anti-allergy medications have proven effective in the treatment of the majority of allergic patients. Vaccination has proven to be a potent modality for the prevention of many infectious diseases and a number of effective antimicrobial therapies exist for the treatment of others. However, there are serious deficiencies in our ability to prevent and treat allergic and infectious diseases and new and better therapeutic modalities continue to be needed. Recently, gene vaccination has gained attention as a potential approach for the development of vaccines that prevent and treat both allergic and infectious diseases [7, 14, 25, 29, 32, 38]. It has been shown that gene vaccination induces long-lasting and potent Th1-biased immune responses, which include cytotoxic T lymphocyte (CTL) activity [7, 25, 29, 38]. In contrast, immunization with the same antigen as a protein induces a Th2-biased immune response without CTL activity [29, 31, 38]. The immune response elicited with gene vaccines is well suited for the induction of protection against allergic pathology and the prevention of infection. Furthermore, plasmid immunization has proven effective in the prevention of allergic responses and infection in animal models [7, 14, 25, 32]. However, there is limited evidence that gene vaccination can reverse allergic hypersensitivity and no evidence that gene vaccination can modify the course of an ongoing infection [29].