Progressive invasion of cell nuclei by measles virus in persistently infected human cells.

The distribution of measles virus antigens in an auto-degenerating persistently infected human cell line (AV3A1/MV) was examined by a direct fluorescent antibody technique. The appearance of virus antigens in cell nuclei increased with time and passage number, and correlated to a decrease in cell replication rates and increases in cellular pathology and mortality. Nuclei which had been invaded by virus antigens were frequently swollen and the cells tended to have round rather than cuboidal morphologies. The correlation between cell degeneration and viral nuclear invasion in this system suggests that quantification of viral nuclear invasion may be useful as a pathological marker of relative cell morbidity in persistent measles virus infections.