Fig. 1.

Cytotoxic activity of human allospecific effector CD8⁺ T lymphocytes. The killing of specific target (human JY B cell line) and irrelevant cell lines (Raji and Daudi) were studied. Cytotoxicity was evaluated by DiOC₁₈(3) – propidium iodide two-color flow cytometric measurement. DiOC₁₈(3)-labeled target cells (10,000 cells per well) were incubated for 3.5 h in the presence of the indicated amounts of effector cells (E/T ratio). For the last 30 min, propidium iodide was added, and the percentage of the live target cells was measured. Specific lysis was calculated as described in Materials and Methods. Results shown represent four independent experiments. (Inset) The result of flow cytometric analysis of CD4/CD8 double-stained forward and side light scatter-gated lymphocytes.