Replication of measles virus and localization of the viral antigens in long-term infection in organotypic cultures of hamster dorsal-root ganglion.

To investigate measles virus replication and expression of the individual viral proteins in differentiated various types of cells in neural tissues free from immunological effects organotypic cultures of hamster dorsal-root ganglion were employed. Measles virus caused long-term infection up to 100 days in these cultures to which the virus was inoculated after they had been well-organized with myelination. Electron microscopy and immunofluorescence technique demonstrated that the infection proceeded first in cells other than neurons and then gradually spread to neurons leading to degeneration of all neurons. By immunofluorescence staining with monoclonal antibodies against measles virus structural proteins, hemagglutinin (HA), fusion (F) protein, nucleocapsid major (N) protein, phosphorylated (P) protein and matrix (M) protein, all the viral antigens including M protein but except P protein were clearly shown in the cytoplasm of neurons and N and F proteins were observed also in neurites. In non-neuronal cells all the viral antigens including P protein were observed in the cytoplasm. Only N antigen was shown also in the nucleus of all cell types including both neurons and Schwann cells. These findings were discussed in relation to the viral replication pattern in subacute sclerosing panencephalitis.