Table 1.

CD8⁺-mediated suppression is separable from cell lysis

Experiment	CD8+ T cell lines	CD4+ T cell	CD8+	Cytolysis
I	JR-HVS	Single donor (EW)	+*	−
II	NS-HVS	Single donor (DS)	−	+
III	JR-HVS	Donor pool	+	+

^*The plus signs indicate either >90% suppression or >10% cytolysis, both of which are the positive cutoffs for these assays. The negative signs denote <90% suppression or <10% cytolysis. Experiments: I, 98% suppression, 3.4% cytolysis; II, 34.5% suppression, 24% cytolysis; III, >99% suppression, 17.9% cytolysis. Percentage of suppression was calculated based on a control infection in CD4⁺ targets from a pseudotyped virus CD8⁺ suppression assay, and percentage of cytolysis was calculated from a standard chromium release assay (38). NS-HVS cells are nonsuppressing CD8⁺ T cells that were derived from the original JR-HVS cells after long term culture.