Herpesvirus vaccines: an update.
The development of vaccines against the herpesviruses has major public health importance because of the wide spectrum of associated clinical disease with this virus in both immunocompetent and immunocompromised populations. Because these viruses establish latent infections capable of subsequent reactivation, both immunotherapeutic and prophylactic vaccine strategies are needed. A range of vaccine formulations has been devised, largely as a result of the rapid growth in knowledge in molecular microbiology and genetic engineering, including live and inactivated whole virus vaccines, and subunit vaccines consisting of recombinant viral glycoproteins in various adjuvants. The live attenuated virus Oka strain vaccine is now licensed for prophylaxis against varicella (VZV) in some countries. Recent studies with herpes simplex viruses (HSV) have demonstrated immunogenicity with glycoprotein vaccines; however, these studies have also highlighted their failure to reduce seroconversion to HSV-2 in high-risk populations. Nevertheless, his work has helped develop comprehensive methodologies for the clinical amd immunological assessment of newer vaccine formulations which have proved successful in animal models. The live attenuated Towne strain vaccine has been shown to prevent severe human cytomegalovirus (CMV) infection in transplant recipients. More recently, subunit antigens and virus vector vaccines against CMV and Epstein Barr virus (EBV) have been devised. Novel attempts to present viral antigens now include the development of plasmid expression vectors for viral nucleic acids and genes as well as engineered live vectors for viral antigens. These new technologies may allow future vaccines to be devised, not only against the 5 well characterised herpes viruses, but also against the recently recognised herpes viruses 6, 7 and 8 whose full clinical spectrum is still unknown.
Jennings
R
R
Division of Molecular and Genetic Medicine and Sheffield Institute for Vaccine Studies, Sheffield, England.
Green
T
T
Kinghorn
G R
GR