Secretory immunoglobulin a and herpes keratitis.

The sensitization of herpes simplex virus by immunoglobulin G (IgG) antibodies was studied. Although herpes simplex virus sensitized by IgG could not be neutralized by IgA antibodies known to neutralize a similar number of unsensitized viruses, this protection could be overcome by larger amounts of IgA antibodies. This suggests that the effective neutralization of herpes simplex virus in ocular tissue is dependent on the relative concentrations of IgA and IgG antibodies. In vivo sensitized virus was isolated from chronically infected animals, and this may be the mechanism by which herpes simplex virus persists in animals with high titers of circulating antibodies in their serum.