Complement-fixing antibody to the AG-4 antigen in herpes simplex virus type 2-infected patients.

Sera collected from confirmed herpes simplex virus type 2 (HSV-2) patients were found to be devoid of complement-fixing antibody to the AG-4 antigen at the time of the herpes lesion outbreak in 10 out of 13 cases. However, 1 to 4 weeks after HSV-2 lesion appearance, 28 out of 30 patients acquired complement-fixing antibody to the AG-4 antigen. The sera of these patients contained immunoglobulin M antibody activity and the ability to immunoprecipitate a 160,000-molecular weight early HSV-2 antigen (the AG-4 antigen). Also, these sera were used to show that a variety of anti-herpes virus compounds had a negligible effect on AG-4 production in HSV-2-infected HEp-2 cells. The majority of the compounds tested (including acycloguanosine and phosphonoformate) are known to inhibit late antigen production, suggesting that the AG-4 antigen is an early antigen. It is probably an immediate early antigen (alpha) as it is formed in the presence of cycloheximide and actinomycin D, a treatment which is used to accumulate alpha proteins.