Fig. 4.

Lysis of HLA–A24 tumor cells expressing MAGE-4. a LB831-RCC is an A*2403 renal cell carcinoma cell line and LB017-HNSCC an A*2402 squamous cell carcinoma of the head and neck. K562 is a target for natural killer cells. The tumor cell lines were treated for 6 days with 50 U/ml IFN-γ. Targets were ⁵¹Cr-labeled and, if indicated, pulsed for 5 min with 1 μg/ml of MAGE-4 peptide NYKRCFPVI. CTL clone 13 was added at the indicated effector-to-target ratios and chromium release was measured after 4 h. b Unlabeled LG2-EBV competitor cells were added to 1,000 ⁵¹Cr-labeled targets before adding CTL 13 at an effector-to-target ratio of 10. If indicated, LG2-EBV were pulsed for 30 min at room temperature with 5 μg/ml of peptide NYKRCFPVI, and washed