Tolerance and suppression of immunity to herpes simplex virus: different presentations of antigens induce different types of suppressor cells.

In this report, we examine tolerance (hyporesponsiveness) and suppression of delayed hypersensitivity (DH) to herpes simplex virus (HSV) in mice, using two different forms of tolerogen: HSV particles and HSV-infected spleen cells. The intravenous injection of mice with either HSV particles or spleen cells 7 days before subcutaneous immunization with virus induced a profound state of unresponsiveness. This unresponsive state was mediated, at least in part, by suppressor T cells (Ts), which were demonstrated by passive transfer to naive recipients. However, different types of Ts were induced depending on the form of the tolerogen. The injection of HSV particles induced Ts which suppressed the induction but not the expression of DH. On the other hand, the injection of HSV spleen cells induced two types of Ts: one which inhibited the induction of the DH response and one which inhibited the expression of DH to HSV. Both tolerance and Ts are virus specific (i.e., the DH response to an unrelated virus was not inhibited) but not type specific for HSV type 1 and HSV type 2. Since both virus particles and virus-infected cells may be present in the blood during HSV infection, the induction of this type of immune regulation may influence the outcome of both acute and latent HSV infections.