Figure 7.

U937 cells co-stimulate predominantly CD8⁺ T cells in the CD3-dependent proliferation assay. U937cells (irradiated, 10⁴) were in the presence of co-cultured with 2×10⁵ T cells, purified CD4⁺ T cells, or purified CD8⁺ T cells (prepared as outlined in the Materials and Methods) and 0·1 μg/ml CD3 mAb (UCHT1). Proliferation was assessed between 48 and 64 hr of culture by [³H]thymidine incorporation between 48 and 64 hr of culture. The results are expressed as the mean percentage inhibition of T-cell proliferation in triplicate wells ±% error. Similar results have been obtained in at least two other experiments.