Histopathology of SV40 infection of spinal cord. (A-C) Hematoxylin and eosin-stained sections show extensive demyelination, necrosis and perivascular lymphoplasmacytic cuffing. (C) There are 5- to 7-µm amphophilic intranuclear viral inclusions within glial cells (black arrows). (D) Luxol fast blue stain for myelin demonstrates extensive myelin loss. (E, F) Immunohistochemical stains for SV40 large T Ag- (E) and SV40 VP1 (F) -positive cells reveal comparable expression of early and late SV40 viral proteins. Scale bars: A, 500 µm; B, 100 µm; C; 20 µm, D-F, 100 µm.