Type specificity of complement-requiring and immunoglobulin M neutralizing antibody in initial herpes simplex virus infections of humans

N J Schmidt, B Forghani, E H Lennette
1975 Infection and Immunity  
Studies comparing the enhancing effect of guinea pig complement on homotypic and heterotypic neutralizing antibodies produced in initial herpes simplex virus (HSV) infections of humans indicated that antibodies to HSV type 1 and HSV type 2 were enhanced to about the same extent, and there was no significant difference in the degree to which complement enhanced homotypic and heterotypic HSV-neutralizing antibody. Homotypic and heterotypic immunoglobulin G neutralizing antibodies were enhanced by
more » ... es were enhanced by complement to as great, or greater, an extent as immunoglobulin M (IgM) HSV antibodies in the same sera. In patients with initial HSV type 1 infections, the IgM neutralizing antibody response was type specific. On the other hand, patients with initial HSV type 2 infections produced both homotypic and heterotypic IgM neutralizing antibody. An initial HSV type 2 infection in an individual previously infected with HSV type 1 elicited the production of IgM neutralizing antibody to both HSV type 1 and HSV type 2. However, patients with recurrent HSV type 1 infections failed to produce IgM antibody to either HSV type during reactivation of the virus. Various investigators have demonstrated enhancement of herpes simplex virus (HSV)-neutralizing antibody by fresh guinea pig complement (5, 6, 8, 10, 12, 13), but information is lacking on the type specificity of complementrequiring neutralizing antibodies in HSV infections of humans, and on the degree to which complement enhances neutralizing antibody in various classes of immunoglobulins in human HSV infections. However, in experimental infections of rabbits, Hampar et al. (5) found that antibodies in different classes of immunoglobulins varied in their complement requirements for neutralization of HSV. It is well established that immunoglobulin M (IgM) antibody is produced in initial infections with HSV, but little has been reported on the type specificity of the response. Hampar et al. (4) reported that, in rabbits immunized with HSV types 1 and 2; the late 19S neutralizing antibodies were highly type specific, whereas early 19S and both early and late 7S antibodies lacked type specificity. Investigators using the indirect hemagglutination (IHA) test for assay of HSV antibody have detected type-specific IgM antibody in early sera from human type 2 HSV infections (1, 9; W. A. Farris, J. A. Stewart, and J. R. Evrard, Abstr. Annu. Meet. Am. Soc. Microbiol. 1974, p. 256, V 337). The present report describes the results of 721 studies on the type specificity of the IgM-neutralizing antibody produced in initial HSV type 1 and type 2 infections, and the enhancing effect of complement on homotypic and heterotypic IgM and immunoglobulin G (IgG) neutralizing antibodies elicited by initial HSV infections. The use of a highly sensitive and specific radioimmunoassay method (B. Forghani, N. J. Schmidt, and E. H. Lennette, J. Clin. Microbiol., in press) for typing HSV antibody permitted accurate determination of the patients' current infecting virus type and indicated whether the patients had previously experienced an infection with the HSV heterotype. MATERIALS AND METHOD)S Neutralization tests. The MacIntyre strain of HSV type 1 (HSV-1), obtained from the American Type Culture Collection, and the Johnson strain of HSV type 2 (HSV-2) were employed for neutralizing antibody assays. The latter strain was isolated in this laboratory from a neonatal herpetic infection and was typed by A. Nahmias. The plaque reduction neutralization test for HSV antibodies was performed as described elsewhere (11) in human fetal diploid lung cells in Linbro FB-6 plates (Linbro Chemical Co., New Haven, Conn.). Hanks balanced salt solution containing 5% inactivated fetal bovine serum was used as a diluent for serum, virus, and guinea pig complement. Tests were conducted in parallel in the absence of fresh guinea pig complement, and in the presence of ap-on May 9, 2020 by guest http://iai.asm.org/ Downloaded from
doi:10.1128/iai.12.4.728-732.1975 fatcat:p2nul4hi35bwpbd4wl5ov6ngc4