Temperature sensitive virus from Aedes albopictus cells chronically infected with Sindbis virus

Cultures of Aedes albopictus cells persistently infected with wild type Sindbis virus (SV W) give rise to small plaque forming mutants which are also temperature sensitive. These mutants, designated SV C, are neutralized by antiserum produced against SV W. Mutant ts clones were isolated from SV C by plaque purification. After serial undiluted passage in BHK or mosquito cells, each of the clones gave rise to ts+ revertants which, however, remained mutant with respect to plaque morphology. Nineteen of 20 clones derived from SV C were RNA+, and one was RNA^- (SV C 2). The RNA synthesizing activity, once induced in infected cells by SV C 2, was stable at the nonpermissive temperature (39.5°C). All clones derived from SV C were inactivated at 60°C much more quickly than was SV W. It was not possible to demonstrate complementation between any of the SV C clones.