Titration of Newcastle disease virus and its neutralizing antibodies in microplates by a modified hemadsorption and...

Using the microtiter system, titration of Newcastle disease virus infectivity and neutralizing antibodies was carried out in chicken embryo fibroblasts grown in "U" or flat-bottomed plates. Infectivity was detected by a combined hemadsorption-hemagglutination method. Inhibition of that reaction indicated the presence of neutralizing antibodies. A 24-h microneutralization test was developed and compared to the plaque neutralization and microhemagglutination inhibition test. Reproducibility of the microneutralization test was statistically analyzed.