Human Cytomegalovirus: Properties of the Complement-Fixing Antigen

Abstract

Summary The correlation between infectivity, virus particle counts, and complement-fixing activity was studied with cell-associated and fluid phase preparations of two strains of human cytomegalovirus. CF antigen was detected only in cellassociated virus preparations and was not found in fluid phase virus preparations. The CF antigen obtained from cell-associated virus preparations was found to be stable at 4°C but was unstable at 37°C, which is just the reverse behavior of cytomegalovirus infectivity. When subjected to ultracentrifugation at speeds which sedimented virtually all of the virus particles, about 50% of the CF antigen behaved as a subviral “soluble” component and remained in the supernatant fluid.