Analysis of the HSV-2 early AG-4 antigen.

Genital herpes simplex virus type 2 (HSV-2) infections can be distinguished from present or past HSV-1 infections by an AG-4 antigen complement fixation assay. The assay which utilizes a 4 hour HSV-2 infected cell extract prepared at a multiplicity of infection (MOI) of 1.0 PFU/cell, appears to consist of several viral proteins. Studies using monoclonal antibodies, polyclonal rabbit hyperimmune serum, HSV-1 X HSV-2 intertypic recombinant viruses and polyacrylamide gel electrophoresis suggest that ICP 8 may be one of the major antigens involved in the complement fixing reaction. It is probable that the success of the assay is not due to a true type specificity but rather a threshold phenomenon in which HSV-2 extracts contain more early viral antigens (including ICP 8) and sera from HSV-2 patients contain more complement fixing antibody to these antigens.