Figure 3. Cytotoxic activity of Id-specific T-cell clones.

A, percentage of cytotoxicity measured by ⁵¹Cr-release assay, of T-cell clones against various target cells, including 5TGM1 myeloma cells, unpulsed or Id-pulsed DCs, or B16 tumor cells. B, percentage of apoptotic cells measured by Annexin V-binding assay. T-cell clones were co-cultured with PKH26 red fluorescent pre-labeled 5TGM1 myeloma cells and the cells were collected and analyzed by flow cytometry. A gate was set on the PKH26 positive cell population. 5TGM1 myeloma cells cultured alone were used as control. An effector:target (E:T) ratio of 5:1 was used. Values above histograms represent the percentages of Annexin-V positive myeloma cells. C, pooled data from three experiments showing the percentages of apoptotic 5TGM1 myeloma cells induced by T-cell clones measured by Annexin V-binding assay. CD8⁺ or CD4⁺ T cells from splenocytes of naïve mice served as controls for effector cells. Representative results of three independent experiments are shown. ** P < 0.01 compared with 5TGM1 alone.