Comparative evaluation of four commercially available monoclonal antibodies for culture confirmation of herpes simplex virus infection.

Four fluorescein isothiocyanate-labelled monoclonal antibody typing reagents were compared for intensity of fluorescence and sensitivity in confirming herpes simplex virus (HSV) in cell culture. A total of 125 (50 HSV type 1 [HSV-1] and 75 HSV-2) specimens positive for HSV were concurrently stained with type-specific monoclonal antibodies from Bartels (Bartels Immunodiagnostic Supplies, Inc., Bellevue, Wash.), Kallestad (Pathfinder; Kallestad Diagnostics, Chaska, Minn.), Diagnostic Products Corp. (DPC) (PathoDx; DPC, Los Angeles, Calif.), and Syva (Microtrak; Syva Co., Palo Alto, Calif.). Fifty cultured specimens not displaying HSV-associated cytopathic effect were also stained. Each of the four reagents confirmed the 50 negative cultures and 125 positive cultures. One HSV-1-positive culture was missed by the Kallestad antibody. Ten HSV-1 isolates displayed dull fluorescence when stained with the Syva HSV-2 reagent. The other three reagents stained only the HSV-1 well with these 10 specimens. The Syva and Bartels stains were brighter, in general, than the Kallestad and DPC stains. However, the Kallestad and DPC stains were brilliant enough to allow interpretation without hesitation. The differences in intensity and background staining emphasize the need for laboratories to routinely perform quality checks on their reagents and to test new products which become commercially available.