Regulation of Herpes Simplex Virus-specific Lymphoproliferation by Suppressor Cells

We investigated the regulation of the herpes simplex virus (HSV)-specific lymphoproliferative response (LPR) by suppressor cells. The chief cell types in HSV-immune splenocytes proliferating in response to the antigen were Lyt 1+ and Lyt 2+ T cells, which accounted for approximately 60 and 40% of the response, respectively. Because the total responsiveness of splenocytes was enhanced after depletion of Lyt 2+ cells, the LPR was assumed to be subject to regulation by an Lyt 2+ suppressor cell. This was shown to be the case with an experimental design in which suppressor cell activity was induced in one culture, the cells were irradiated, and the effects on LPR were measured in a test antigen-stimulated culture. The cell responsible for suppression was shown to be Lyt 2+ IJ+, and the actual suppressor effect was not antigen specific. Cellular requirements for the generation of suppression were also investigated. The three distinct cell types that appeared to be required were Lyt 2+ and Lyt 1+ T cells and an IJ+ antigen-presenting cell. Of the three cell types, only the Lyt 2+ cell needed to be from HSV-immune animals. The implications of our model system for the better understanding of the role of immunity in herpesvirus pathogenesis are discussed.