Interspecies interactions of arboviruses. III. Competition for virus envelope antigens in mixed Getah and Sindbis virus populations.

Interactions of Getah and Sindbis virus populations in mixed infections of 5 tissue systems were competitive or neutral. The type of interaction is regulated by the host cell and virus population density. On reproduction in mouse brains and SPEV cell cultures the mixed population exhibited antigenic markers of Getah virus; in Syrian hamster kidney and chick embryo cell cultures those of Sindbis virus; and in Chinese hamster kidney cell cultures the antigenic markers of both viruses. Mixed populations with monospecific antigenic characteristics contained genomes of both viruses detectable by the TC marker (dual spetrum of cytopathogenicity). Clonal analysis of such populations confirmed the occurrence of genome masking and demonstrated the formation of genotypically mixed particles. Possible mechanisms of the antigenic dominance of one virus and selective blocking of functions of the other virus are discussed.