The effect of antibody on latent pseudorabies virus infection in vitro

Cytosine arabinoside (Ara C) inhibited the synthesis of pseudorabies virus when Vero cells were infected at a multiplicity of infection of 0.0001-0.05 PFU per cell. On removal of Ara C, infectious virus reappeared after a latent period of 3-5 days. The activation of latent virus was not influenced by elevating the temperature to 40 degrees C at the time of Ara C removal but it was prevented by antiviral antibody. When antiviral IgG was added into the culture fluid of cells either during the incubation with Ara C, or after removal of the inhibitor, the number of infectious centres was reduced to about 10%. The role of antiviral IgG in the maintenance of latency is discussed.