LCM virus antigen was visualized in infected tissue cultures and mouse tissues by the direct immunofluorescent procedure. In all instances, antigen was localized to the cytoplasm.
In intracerebrally infected mice, antigen was almost completely restricted to meninges, choroid plexus, and ependyma; at no time were neurons involved. Mice infected by intraperitoneal inoculation of a viscerotropic strain demonstrated antigen chiefly in liver parenchyma, splenic reticulum, bronchi, and alveolar cells.
Congenitally infected mice showed antigen in almost all cell types observed, but generally in only a minority of cells; infection was often focal in distribution. Liver, kidney, pregnant uterus, and trophoblast were most extensively involved. No antigen was observable in ova of a pregnant mouse.