A Comparative Study of Related Alphaviruses -- a Naturally Occurring Model of Antigenic Variation in the Getah Sub-group

Abstract

The relative susceptibilities of 6 cell culture lines [from hamster, monkey, pig, toad or mosquito] were compared using 6 closely related alphaviruses. Plaque morphology was used as a parameter for biological differences of these viruses in parallel with plaque reduction neutralization tests. One virus showing mixed plaque sizes was plaque purified and the 2 variants obtained were compared by in vivo and in vitro methods. The implications of plaque variants within a mixed virus population are considered along with possible natural selective mechanisms in the evolution of these related viruses of sympatric distribution.