Alphavirus expression vectors

Abstract

Publisher Summary This chapter describes the mechanics, including how alphaviruses function as expression vectors and some features that make them useful. It also describes some of the ways in which alphaviruses have been used and some potential ways they can be of value. Alphaviruses are positive-strand RNA-enveloped viruses. Three of them, Sindbis virus, Semliki Forest virus, and Venezuelan equine encephalitis virus, are becoming widely recognized as expression vectors. The most versatile of these vectors are replicons in which the structural protein genes are replaced by a heterologous gene. They can be packaged into virus-like particles by the use of defective helpers that provide the structural proteins. Alphaviruses and their replicons are normally cytopathic in cultured vertebrate cells, but replicons that have a mutation in one of the nonstructural protein genes have a decreased level of viral RNA synthesis and show either reduced or no cytopathogenicity in some cultured cells, in particular baby hamster kidney cells. Apart from these improvements, alphavirus vectors are beginning to demonstrate their value as vaccines and possibly also for expression in neurons.