DETECTION OF IMMUNOGLOBULIN-M ANTIBODIES TO GLYCOPROTEIN G-2 BY WESTERN-BLOT (IMMUNOBLOT) FOR DIAGNOSIS OF INITIAL HERPES-SIMPLEX VIRUS TYPE-2 GENITAL INFECTIONS

Western blots (immunoblots) for the detection of immunoglobulin M (IgM ) antibodies specific for herpes simplex virus type 1 (HSV-1) and HSV- 2 in patients' sera were developed. The locations of the type-specific glycoprotein G (gpG-2) of HSV-2 (92- and 140-kDa forms) and glycoprot ein C of HSV-1 (gpC-1), which carries mostly type-specific antigenic e pitopes, were checked with specific monoclonal antibodies. Western blo t assays for IgM antibody to gpC-1 or gpG-2 were performed after deple tion of IgG by precipitation with anti-human IgG. In patients with pri mary HSV-2 genital infections, seroconversion of IgM and IgG antibodie s to both the 92- and 140-kDa forms of gpG-2 was observed, although bo th antibodies appeared in convalescent-phase serum after the first wee k. IgM and IgG antibodies to low-molecular-size polypeptides (40 to 65 kDa) were the first antibodies observed in patients with primary infe ction, but these antibodies were cross-reactive with HSV-1 and HSV-2. However, in patients with recurrent HSV-2 infections, IgG antibodies t o both forms of gpG-2 and the low-molecular-size polypeptides were fou nd no matter how early after onset the patient was bled, and IgM to gp G-2 did not appear. In patients with nonprimary initial genital HSV-2 infections, IgG antibody to HSV-1 was demonstrated in the first serum specimen, and HSV-2-specific IgM was found in 39% of the serum specime ns. Hence, the Western blot assay can be used to test for IgM antibody to gpG-2, allowing for the retrospective diagnosis of initial HSV-2 i nfections and its use as a supplementary test to the gpG-2 IgG enzyme- linked immunosorbent assays developed elsewhere. In contrast, IgM anti body to gpG-2 is not usually detected in patients with recurrent HSV-2 infections.