DNA vaccination
DNA vaccination is a technique for protecting against disease by injection with genetically engineered DNA so cells directly produce an antigen, producing a protective immunological response. DNA vaccines have potential advantages over conventional vaccines, including the ability to induce a wider range of immune response types.
Several DNA vaccines are available for veterinary use. Currently no DNA vaccines have been approved for human use. Research is investigating the approach for viral, bacterial and parasitic diseases in humans, as well as for several cancers.
Vaccines have eliminated naturally occurring smallpox, and nearly eliminated polio, while other diseases, such as typhus, rotavirus, hepatitis A and B and others are well controlled. Conventional vaccines cover a small number of diseases, while other infections kill millions of people every year.
First generation vaccines are whole-organism vaccines – either live and weakened, or killed forms. Live, attenuated vaccines, such as smallpox and polio vaccines, are able to induce killer T-cell (TC or CTL) responses, helper T-cell (TH) responses and antibody immunity. However, attenuated forms of a pathogen can convert to a dangerous form and may cause disease in immunocompromised vaccine recipients (such as those with AIDS). While killed vaccines do not have this risk, they cannot generate specific killer T cell responses and may not work at all for some diseases.
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