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HIV Vaccine Designs and Strategies

Vaccine Design

How Does this Vaccine Work?

Issues for HIV Vaccine

DNA
  1. A few HIV genes are inserted into a backbone of DNA known as plasmid
  2. The vaccine is injected into muscle of the recipient where the HIV genes are expressed into proteins.
  3. The viral proteins are degraded into small peptide fragments, which are then presented by molecules on the cell surface. T cells recognizing these molecules generate an immune response.
No DNA vaccines have yet been approved for use in humans by the FDA. FDA guidance on DNA vaccines can be found on FDA's Considerations for Plasmid DNA Vaccines for Infectious Disease Indications
Live Vectors: (Viral and Bacterial)
  1. The HIV or SIV genes are inserted into the genomes of live, infectious, but non-disease-causing forms of viruses (e.g., adenovirus) or bacteria (e.g., Bacille Calmette-Guerin (BCG).
  2. These vectors shuttle “foreign” genes along with their own into cells.
  3. HIV proteins generated from these recombinant genes inside the cell are either secreted or displayed on the cell surface and presented to the immune system.
  1. The development of viral vectors has been robust, with a few entering Phase III trials.
  2. Only a few bacterial vectors are under development in small and large animal models, and some Phase I trials.  The complex nature of bacteria hampers the development of bacterial vector systems.
Viral Proteins or Viral Peptides Chemically synthesized pieces of HIV peptides or proteins that elicit strong T and B cell responses. Peptide-based preparations require the addition of an adjuvant to enhance immunogenicity. At present, alum is the only adjuvant authorized by FDA for general medical use, however many products are being tested, and some are in clinical trials.
Virus-like Particles (VLPs)
  1. Empty, non-infectious shells of the HIV envelope protein; they mimic the outer coat of the virus but lack a genome inside and cannot reproduce.
  2. Because VLPs resemble the virus, they can induce high titers of neutralizing antibodies to protect against viral challenge.
VLPs represent an exciting new strategy for HIV vaccines but it has been difficult to make them reproducibly.

Last Updated July 27, 2012

Last Reviewed July 27, 2012