Electron microscope study of the interaction of vaccinia virus with macrophages from immunized and nonimmunized rabbits.

A study using the electron microscope was conducted with the objective of comparing the efficiency of phagocytosis and the subsequent fate of the vaccinia virus in immune and nonimmune rabbit macrophages. Although immune rabbit macrophages inhibited viral replication, they did not differ from permissive nonimmune rabbit macrophages in their ability to ingest the virus. In addition, the immune cells processed the vaccinia virus through the first stage of uncoating as evidenced by the observation of viral cores in the cell cytoplasm. These data support the thesis that the failure of vaccinia replication in immune macrophages is a function of intracellular mechanisms which operate at some point in the replicative sequence after the first stage of uncoating.