The regulation of herpes simplex virus-specific CTL induction by suppressor cells

The incubation of herpes simplex virus (HSV) immune murine splenocytes with HSV antigens induced suppressor cells which inhibited HSV-specific cytotoxic T lymphocyte (CTL) induction. The cell mediating the suppression was identified as a Thy 1+ Lyt 2+ I-J+ cell. The induction of this suppressor cell required the participation of at least three leukocyte populations. That is, depleting the cultures of either Lyt 1+ or Lyt 2+ splenocytes resulted in a failure to induce suppressor cell activity. Likewise the removal of macrophage-like antigen-presenting cells (APC), in particular I-A- I-J+ APC, abolished suppressor-cell induction. Though the Lyt 2+ I-J+ cells had to be provided by HSV-immune mice, both the APC and the Lyt 1+ cells could be provided by HSV-naive mice. Though the induction of the suppressor cell was virus specific, its action was nonspecific as evidenced by the suppression of influenza-specific CTL induction. The implication of our results for the understanding and manipulation of herpesvirus disease is briefly discussed.