Sendai virus infection in the brains of mice: distribution of viral antigens studied with monoclonal antibodies.

Newborn and 12- and 21-day-old mice were inoculated intracerebrally with Sendai virus. Titers of infectious virus peaked on days 1-2 after infection and had disappeared after three days in 12- and 21-day-old mice and six days in newborn mice. The levels of infectious virus in the brain declined before the appearance of serum antibodies, which in newborn mice was delayed until day 12. Immunofluorescence analysis showed viral antigens in neurons and their dendritic processes 12 and 24 days after infection in newborn animals but not in older ones. Immunofluorescent staining with monoclonal antibodies to five major structural components of Sendai virus--the nucleocapsid, polymerase, matrix, fusion, and hemagglutinin-neuraminidase proteins--showed that all were present in choroid plexus epithelial cells and ependymal cells during acute infection. However, during acute and persistent infections in neurons, the first three antigens were found, but the last two--surface glycoproteins--were lacking or found at low levels.