Growth of measles virus in a human macrophagelike cell line: U937

Measles virus infection was established in U937, a continuous human macrophagelike cell line. Unlike cultured human peripheral macrophages, infection resulted in prominent giant cell formation, indicating that these cells are susceptible to viral-induced fusion. Although a high proportion of cells in culture contained measles viral antigen by immunofluorescent assay a relatively small amount of infectious virus was produced. In contrast to continuously cultured human lymphoblastoid cell lines, infection of U937 was lytic, and persistent infection could not be established. The U937 cell line may be useful for further studies of viral interaction with macrophages, including those related to the induction of cell fusion by measles or other syncytium-forming viruses.