Abstract:
Stimulated mouse peritoneal macrophagcs were studied to determine the mechanism by which they express resistance to vaccinia virus. Macrophages from non-immunized animals were harvested and infected with vaccinia in vitro. The virus failed to replicate within the macrophage culture. Autoradiographic
studies revealed that no significant viral DNA synthesis occurred in infected macrophages. An uncoating assay yielded evidence that vaccinia did not undergo replicative second stage uncoating within the mouse macrophage. Examination of infected macrophaees with the electron microscope indicated that vaccinia was retained within the phagocytic vacuole of the macrophage where it underwent at least partial degradation. Because no portion of the viral replicative sequence was detected, the stimulated mouse macrophange appears to be a resistant rather than a non-permissive cell type for vaccinia. It is suggested that the level of mouse macrophage activation may be an important factor in vaccinia resistance.
