Virus-specific IgM and IgG antibody production by B cells during herpes simplex virus type 2-induced immunosuppression as analysed by an immunospot assay.

The mechanism of herpes simplex virus (HSV)-2-induced immunosuppression was analysed by determination of the number of IgM and IgG antibody-secreting B cells in female BALB/c mice using an immunospot assay. Primary HSV-1 or -2 as well as homologous or heterologous booster infections at different times were performed. In accordance with earlier results on humoral antibody generation, in contrast to HSV-1, HSV-2 induced only very low numbers of antibody-producing B cells in dose-response experiments. They appeared late after infection compared to HSV-1. Despite a homologous humoral booster reaction against HSV-1 at day 8 no IgM- or IgG-secreting cells in the spleen could be detected. This non-reactivity of the spleen had vanished 10 days later, when secondary reactions of B cells could be observed. Secondary infections with a high homologous dose of HSV-2 after a low primary dose produced only a low booster response of IgG-secreting B cells. Suppression of humoral antibody production induced by HSV-2 (high dose) waned after more than 50 days, indicating that the HSV-2-induced suppression did not impair antigen presentation or memory cell generation.