Micro-neutralization test for mumps virus using the 96-well tissue culture plate and PAP (peroxidase-antiperoxidase) staining technique.

A rapid micro-test method for mumps virus neutralization was developed. In this method, a 96-well tissue culture plate was used for preparation of cell monolayers and the PAP staining technique was used for visualization of mumps virus infected cells. Clusters of infected cells were observed as a focus and the numbers of foci could be counted by the naked eye 2 days after the infection. A linear relationship between virus dilutions and focus numbers was observed. When neutralizing antibodies in sera from cases of natural mumps infection were assayed, a good correlation was observed between those obtained by the focus reduction method applying the micromethod and those obtained by the ordinary plaque method. Our results indicate that this micromethod is useful in mumps virus neutralization tests and it has many advantages over other methods previously reported.