A fluoroimmunoassay for measurement and visualization of antibody bound to surface antigens of HSV-infected cells.

An assay based on quantitative spectrofluorometry of surface immunofluorescence was applied to the study of reactions between antibody and surface antigens of viable HSV-infected cells in suspension. Fluorescence was expressed in terms of photon counts per second. Both the direct and indirect fluorescent antibody techniques proved acceptable for assay of surface reactions, yielding values of specific fluorescence as high as eight times those of controls. Fluorescence microscopy of cell populations assayed by spectrofluorometry allowed for simultaneous visual examination of surface antigens. Comparison of the fluoroimmunoassay with the 51Cr-release test for cytolytic antibody to HSV-induced surface antigens revealed the latter to be the more sensitive, with antibody titres ranging up to four times those detected by fluoroimmunoassay. General correlation between the two assays was found using both rabbit and human sources of antisera.