The use of an enzyme-labelled assay as an aid to reading micro virus-neutralisation tests.

An indirect immunoperoxidase technique has been developed for the detection of virus-infected cells after completion of a micro virus-neutralisation test. This allows visual rather than microscopic reading of the plates, which is less time-consuming and does not require a technician skilled in distinguishing between specific viral cytopathic effect and non-specific cytotoxicity. The technique proved to be more sensitive than microscopic reading for the detection of low levels of antibody and could be of great use for other viruses which do not produce a marked cytopathic effect on cells or have a slow growth rate, making development of a standard virus-neutralisation test very difficult.