Evaluation of a monoclonal antibody typing system for herpes simplex virus

This study compared conventional viral isolation (VI) in cell cultures with a commercial product--Virgo antigen detection system--for the identification and typing of herpes simplex virus (HSV). The system is designed to identify and type HSV from direct lesion smears (DS) and from cell culture smears (CS) infected with a swab from the patient's lesion by means of an indirect fluorescence assay (IFA) using HSV type-common and HSV-2 type-specific monoclonal antibodies. A total of 71 coded specimens manifesting clinical characteristics consistent with HSV were included in this evaluation from which DS, CS, and VI were performed. Specimens were taken from a variety of intraoral and extraoral sites, from both recurrent and primary lesions, and at various stages of lesion progression. The results showed that HSV was not detected in 22 of the 71 specimens by either DS, CS, or VI. Forty-nine specimens were positive by both CS and VI; 47 of these were typed as HSV-1 and 2 were typed as HSV-2. Thirty-eight of the 49 positive CS and VI specimens also were positive by DS. The remaining 11 DS slides did not have sufficient cells for analysis. It was concluded that the success of a valid DS test depended on the stage of the lesion and the sampling technique. The sensitivity and specificity of CS and DS were 100% and 82%, respectively, for detection of virus when compared with VI. When done properly with an adequate number of cells from the lesion, the DS proved to be an accurate and rapid (2 hours) procedure.