Appearance and persistence of antibodies against different virus components after regular measles infections.

Different measles virus-specific antibody activities in acute, early (11 to 40 days after rash) and late (4 to 20 years postinfection) convalescent sera and gamma globulin were determined. Early immunoglobulin G antibodies gave a poor neutralization, which was increased 10- to 60-fold by addition of anti-gamma globulin. There was a high degree of correlation between titers of hemolysis-inhibiting (HLI) and hemagglutinating-inhibiting (HI) antibodies. However, in one out of fifteen late convalescent sera an HLI antibody titer of 640 in the presence of titer of only 20 in HI tests with Tween 80-either-treated antigen was found. Similar findings were made with sera from two patients with multiple sclerosis included in a parallel study. A somewhat higher titer of HI antibodies was demonstrable in these three sera when untreated material was used as antigen. These findings are interpreted in the following way. Antibodies against the hemagglutinin can block not only virus-specific agglutination but also lysis of red cells. In contrast, antibodies against the hemolysin, besides blocking the biological activity of this component, carry only a slight HI activity. This HI activity can be detected only by use of antigen preparations containing hemagglutinin-associated hemolysin.Complement-fixation (CF) and immunodiffusion tests (the latter were carried out with antigen preparations treated with 0.25% sodium dodecyl sulfate) demonstrated that, in almost all cases, antibodies against nucleocapsid structures dominated quantitatively among antibodies appearing in connection with and persisting after regular measles infections. Generally, only low titers of antibodies reacting with purified small particle hemagglutinin (HA; 10 to 14S) or additional structural or nonstructural components were identified in CF and immunodiffusion tests.