Characteristics on the adenoviruses. III. Reproductive cycle of types 1 to 4

The strains of types 1 to 4 adenoviruses studied attained maximum combination with host cells, strain HeLa, in 5 to 6 hours. During this adsorption period approximately 75 per cent of the total virus became associated with the host cells. Following adsorption of virus to HeLa cells, these agents underwent cyclic multiplication periods similar to bacterial and other animal viruses. The latent or eclipse period of the multiplication cycle for types 1 and 2 viruses was 17 hours, whereas the types 3 and 4 agents had a latent period 14 to 15 hours in length. The rate of viral propagation during the incremental period was very similar for types 1, 2, and 4 viruses, but was slower for the type 3 agent. During the incremental period of viral propagation newly synthesized virus was not released into the fluid phase of the culture and even after 6 days of viral multiplication when marked cytopathic alterations of the infected HeLa cells had occurred, the spontaneous release was only 2 to 6 per cent of the total virus detectable.