Target cells of human adenovirus type 12 in subtentorial brain tissue of newborn mice. I. Cyto-histomorphologic and immunofluorescent microscopic studies.

Human adenovirus type 12 (Ad 12) was inoculated through subtentorial route into inbred newborn mice (C3H/BifB/Ki), and sequential changes of the brain and tumor induction were examined by histological and immunofluorescent methods. Two days after virus inoculation, Ad 12 specific tumor antigen (fluorescent T-antigen) appeared in the cells of ependymal and subventricular matrix layers, choroid plexuses and leptomeninges in the subtentorial as well as the supratentorial brains. After 10 days, these fluorescent positive cells decreased gradually in number but still remained focally beneath the ependyma. Sixty days later, early tumor nodules were detected in the same regions in which remained the fluorescent cells. After 107 days, neurological signs and well-developed tumors were noted in 25 of 63 (30.1%) mice examined. In the cerebellum, both of T-antigens and tumors were limited around the IVth ventricle, but not in the granular layers. Histomorphologically, the tumors were of primitive neuroectodermal origin and consisted of the cells resembling immature matrix cells in the subventricular zone. These findings strongly suggest that the virus has a selective affinity to the remaining matrix cells, but not to cerebellar granular cells, at least, in newborn mice.