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⁺ Lyt2⁺ 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 lyht 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.