Long-term suppressor cell lines. II. Suppressor-target interactions.

Long-term nonhybridized murine suppressor T cell (Ts) lines, some of which have been in culture for over one year, are genetically restricted in their ability to suppress proliferation of primed lymph node cells (LNC). The genetic restriction maps to the I region of the major histocompatibility complex and resides in either the I-A, I-E or I-J locus. Suppressive activity is only slightly decreased following irradiation of the Ts with 2000 rds. The target for suppressive activity expressed by Ts cell lines is the helper T cell as suggested by experiments in which LNC proliferation was maximally suppressed when Ts were present early in the assay culture. The identity of the target cell was confirmed by experiments in which Ts were shown to suppress the anti-human gamma globulin plaque-forming cell response resulting from co-culture of primed B cells with cloned human gamma globulin-specific helper T cells.