[Genetic immunization--"the biological equivalent of cold fusion"?]

Genetic immunization is a new vaccine technology, where antigen encoding DNA plasmids are directly injected into muscle or skin with the purpose of eliciting an immune response to the gene product. The gene products are correctly glycosylated, folded and expressed by the host cell. This is an advantage when the antigens are difficult to obtain in the desired purity, amount or correctly glycosylated form or when only the genetic sequences are known e.g. HCV. The DNA plasmids are injected into muscles or delivered coated onto gold microparticles into the skin by a particle bombardment device, a "gene gun". Genetic immunization has demonstrated induction of both a specific humoral but also a more broadly reacting cellular immune response in animal models of cancer, mycoplasma, TB, malaria, and many virus infections including influenza and HIV. Thus, the DNA vaccine mimics a live vaccine without the biohazard. Many animal species have responded to genetic immunization and gene vaccine has also been used to induce a desired immuneresponse in patients with cancer and HIV. The technique was first described in 1992 but is developing fast. This review describes the history and principle of the technology, its advantages, problems and possible applications.