Studies on Epstein-Barr virus-related antigens. I. Indirect single radial immunodiffusion as a useful method for detection and assay of soluble antigen.

A useful method for the detection and assay of Epstein-Barr virus (EBV)-related soluble antigen has been developed by the application of the indirect single radial immunodiffusion technique which is frequently used for quantitative measurements of immunoglobulins and other soluble proteins. When the extracts of EBV-determined nuclear antigen (EBNA)-positive non-producer cells (Raji and NC-37) were applied to agar plates containing seropositive human serum, followed by overlay with anti-human IgG serum, ring-shaped precipitates with high specificity were clearly evident. The size of such precipitin rings was proportional to the amount of the antigen. This method is simple and applicable for a quantitative assay of a particular EBV-related soluble antigen and antibody and the sensitivity is equivalent to that seen with the complement fixation test.