Translational mobility of concanavalin A receptors in normal and neoplastic glial cells.

The dynamics of cell-associated Concanavalin A (Con A) in astrocytes of the newborn rat (RNA), the rat glioma (AC), and the human glioblastoma (GB) were studied in vitro by fluorescence and electron microscopy. Con A receptors on the cell surface were seen usually as a continuous thin layer, and Con A accumulations in fluorescence microscopy were actually Con A receptors on complicatedly infolded cell membrane and collection of Con A pinosomes. No capping occurred in the three types of glial cells. The translational movement of Con A receptors on the cell surface was rapid in the AC, slow in the RNA, and intermediate in the GB, and partly associated with Con A internalization. Con A pinosomes were more numerous in the RNA compared with those in the AC and the GB. Colchicine accelerated the translational mobility of surface Con A receptors more markedly in the AC and the GB than in the RNA. The translational movement Con A receptors, when treated with cytochalasin B, was retarded in the RNA and the GB and rather accelerated in the AC. Con A pinosomes were decreased in the three types of glial cells by treatment with colchicine or cytochalasin B.