Antibodies against mumps virus component proteins

The neutralization (NT) test is regarded as the most reliable method for detection of protective antibodies, but islabor-intensive and time consuming. Enzyme-linked immunosorbent assay (EIA) is frequently used in sero-epidemiologicalstudies because of its simplicity and ease of use. In this study, immunofluorescent (IF) antibodies against nucleocapsid (N),fusion (F), and hemagglutinin-neuraminidase (HN) proteins were investigated in comparison with NT and EIA antibodies. Theantibody against N protein was dominant in serum samples obtained from patients with a previous history of mumps infection.Titers of antibodies against F and HN proteins were very low. Many serum samples were positive for EIA but negative for NT,and no significant correlation was noted between NT and EIA antibodies. Among the three component proteins, correlation ofEIA and IF antibodies with N protein was relatively good. After vaccination with mumps vaccine, EIA positivity was closelyrelated to the IF antibodies against N protein, and after vaccination NT-positive sera became positive for IF antibodiesagainst F and HN proteins. IF antibodies against F and HN proteins were considered to have a strong association with NTantibodies, and those against N protein were considered to have a strong association with EIA antibodies.