Properties of Sindbis virus variants from infected Culex tarsalis mosquitoes.

Plaque-purified Sindbis virus was passed three times in Culex tarsalis mosquitoes and progeny viruses were isolated by plaque purification on a cloned line of Aedes albopictus cells. Nine of ten clones examined differed from wild-type (wt) virus with respect to their plaque morphology characteristics in chick embryo fibroblast (CEF) and/or A. albopictus cells. Seven clones were temperature-sensitive and failed to replicate or synthesize viral RNA in CEF cells at 41 degrees C. At 35 degrees C in CEF cells the majority of isolates synthesized less viral RNA than wt virus. In contrast, all cloned isolates synthesized viral RNA more rapidly than wild-type virus in A. albopictus cells.