Target cells of human adenovirus type 12 in subtentorial brain tissue of newborn mice. II. Cytomorphologic and immunofluorescent microscopic studies in vitro.

The normal subtentorial brain cells of newborn mice (C3H/BifB/Ki) were cultured by the monolayer culture technique. The first subculture was inoculated with human adenovirus type 12 (Ad 12) in an attempt to achieve the transformation of the brain cells. Normal cultured cells were morphologically divided into astrocytic cells (Ac-1 cells and Ac-2 cells), immature brain cells including undifferentiated cells (Ud cells) and glioblastic cells (Gb cells), and fibroblastic cells (Fb cells). Fluorescent T-antigen first appeared in all type of cells and gradually decreased. Later, fluorescent T-antigen remained mainly in the immature brain cells (Gb cells) which grew in clusters on the epithelioid areas of astrocytic cells. From 21 days after Ad 12 infection, transformed foci appeared in such epithelioid areas. Morphologically, the transformed cells resembled immature brain cells, especially Gb cells, in vitro. They often showed rosette-like structures, cystic spaces and trabecular patterns in the subcultures. Tumors which developed through the transplantation of the transformed cells into subcutaneous tissue and brain of mice were quite similar to original brain tumors induced by Ad 12. From these findings it is strongly suggested that, in vitro, the target cells of Ad 12 in the subtentorial tissues of the mouse brain are immature brain cells, probably Gb cells.