Use of protein A-treated sera in unmasking herpes simplex virus type 1 (HSV-1) immunoglobulin A and identifying HSV-1 immunoglobulin G as the predominant neutralizing antibody

Abstract

Treatment of human sera with protein A reduced the amounts of immunoglobulin G (IgG), IgA, and IgM detected by radial immunodiffusion. This treatment also decreased the amount of herpes-specific IgG and IgM detected by radioimmunoassay, whereas it increased and even unmasked the amount of herpesspecific IgA detected. Comparison of protein A-treated sera with untreated sera indicated that herpes simplex virus type 1 IgG was responsible for more than 92 to 99% of the serum neutralizing activity.

Virus-specific immunoglobulin G subclasses in herpes simplex and varicella-zoster virus infections

“…Beck (1) found anti-HSV activity in the IgG3 fraction as determined in a neutralization test. These findings differ from those obtained by Ratner et al (13), who showed a decreased neutralizing activity to HSV in sera after protein A treatment. In our assay, virus-specific IgGl, IgG3, and IgG4 antibodies could be detected in sera from healthy persons known to have IgG anti-HSV.…”

“…The common occurrence of both IgGl and IgG3 with antiherpes reactivity could explain why Beck found antiviral IgG3 (1), whereas Ratner et al (13) found antiherpes activity in sera without IgG3. The differences in neutralizing capacity may be due to differences in methodology or to the choice of sera used in their tests.…”