An immunofluorescence assay for studying replication of adeno-satellite virus.

The simian adeno-satellite virus apparently cannot multiply unless host cells are co-infected with a 'helper' adenovirus. Following simultaneous infection of green monkey kidney cells with simian adenovirus (SV 15) and its satellite, satellite antigen was first detected by immunofluorescence in the nucleus 10 to 12 hr after inoculation, while adenovirus antigen was first detected at 16 hr. A single cycle of growth for satellite virus was completed in about 24 to 48 hr. Inoculation of satellite-flee adenovirus from 10 to 15 hr before inoculation with satellite proved to be the most efficacious time for shortening the latent period of satellite. Satellite antigen could then be detected as early as 4 hr after inoculation. These results indicate that events in the adenovirus replication cycle must proceed for 10 to 12 hr before satellite can be synthesized. An infectivity titration of satellite based on immunofluorescence was developed. The percentage of fluorescent cells in standard monolayers was determined and the infectious units were calculated from the dilution infecting 1 ~ of cells. Most satellite preparations had titres of l0 s to 109 infectious units/ml, with one infectious unit equivalent to 30 to 100 particles.