Interaction between cytomegalovirus and Newcastle disease virus as mediated by intrinsic interference.

Cytomegalovirus (CMV) was demonstrated to induce intrinsic interference to Newcastle disease virus (NDV) in human fibroblast cells under noncytopathic conditions. This interference is unique in that (i) cytomegalovirus is the first DNA virus demonstrated to have this property and (ii) the state of interference was transient and progressively lost as the condition of the cells changed with the development of cytopathic effect. These observations are consistent with the view that the newly formed protein responsible for interference with NDV has a limited half-life and is no longer made when cytopathic conditions are produced by CMV.