Subacute sclerosing panencephalitis: isolation and ultrastructural characterization of a measles-like virus from brain obtained at autopsy.

Abstract

Brain tissue was obtained at autopsy from a patient with subacute sclerosing panencephalitis (SSPE) and kept frozen for nine months prior to attempts at virus isolation. Mixed cultures of trypsinized brain material and Vero monkey kidney cells developed cytopathic changes resembling those associated with measles virus. The cytopathogenic effect (CPE) was transferred by cells, and in later passages, also by culture supernatants. Cells and supematants from cultures showing CPE agglutinated monkey red cells. Haemagglutinationinhibition, immunofluorescent and neutralization experiments showed the cytopathogenic agent to be serologically similar to measles virus. Gel precipitation experiments, on the other hand, indicated differences in antigenic composition between the SSPE cultures and cultures of a vaccine (Edmonston) strain of measles virus. Ultrastructural studies revealed cytoplasmic inclusions of nucleocapsids in the SSPE cultures. The appearance and diameter of the SSPE nucleocapsids differed from those of the vaccine strain. Budding and complete viral particles were seen in both SSPE and vaccine strain cultures. It is concluded that the SSPE agent isolated here is most probably a measles virus, but in some respects different from the Edmonston strain of measles virus.