Genetic exclusion and stable complementation of Sindbis virus.

In an effort to enhance genetic interactions by eliminating spatial or physical barriers between variants of Sindbis virus MgCl2 was used to aggregate infecting viral particles. Mixing viral samples in a 1:1 ratio with 0.5 M MgCl2 produced maximal reduction in plaque forming units (PFU) with minimal cell damage due to MgCl2. Aggregate size was determined to be about 7 PFU. Samples taken at 3,5 and 10 hours after infection with mixed aggregates composed of large and small plaque forming virus indicated that only one type of genome was represented among the progeny particles. In addition, aggregation enhanced complementation and the progeny were stable after several cycles of sonication and passage.