Virus-like particles resemble viruses, but are non-infectious because they do not contain any viral genetic material. The expression of viral structural proteins, such as Envelope or Capsid, can result in the self-assembly of virus like particles (VLPs). VLPs derived from the Hepatitis B virus and composed of the small HBV derived surface antigen (HBsAg) were described over 40 years ago from patient sera. More recently, VLPs have been produced from components of a wide variety of virus families including Parvoviridae (e.g. adeno-associated virus), Retroviridae (e.g. HIV), and Flaviviridae (e.g. Hepatitis C virus). VLPs can be produced in a variety of cell culture systems including mammalian cell lines, insect cell lines, yeast, and plant cells.

VLPs are often used in studies to identify protein components required for viral assembly. VLPs are also a useful tool for the development of vaccines. VLPs contain repetitive high density displays of viral surface proteins which present conformational viral epitopes that can elicit strong T cell and B cell immune responses. Additionally, since VLPs lack genetic material, they provide a safer alternative to attenuated viruses. VLPs have already been used to develop FDA approved vaccines for Hepatitis B and human papillomavirus. More recently, VLPs have been used to develop a pre-clinical vaccine against chikungunya virus.

Gene therapy efforts are focused on utilizing VLPs as a delivery system for genes or other therapeutics.

Research suggests that VLP vaccines against influenza virus could provide stronger and longer lasting protection against flu viruses than conventional vaccines. Production may begin as soon as the genetic sequence of the virus strain becomes available and it may take as little as 12 weeks, compared to 9 months for traditional vaccines. In early clinical trials, VLP vaccines for influenza appeared to provide complete protection against both the Influenza A virus subtype H5N1 and the 1918 flu pandemic. Novavax and Protein Sciences have both run clinical trials of their VLP flu vaccines.

Source: Wikipedia (All text is available under the terms of the Creative Commons Attribution-ShareAlike License)