Fig. 1.
Cytotoxicity and intracellular Ca++ release of 4D4 CTL clone are inhibited by the CD158a receptor.
(A) Cytotoxicity of CD158a+ CTL clone 4D4 was assessed at a 3:1 E/T ratio against RCC and EBV-B–transformed cell lines (LCL) derived from 3 patients: autologous RCC-7 (HLA-A2, Cw4), allogeneic RCC-6 (HLA-A2, Cw3), and RCC-5 (HLA-A9, Cw3). Cytotoxicity was determined in absence (medium) or presence of anti–HLA-B/C or control anti–HLA-DR mAbs (1 of 5 experiments is shown). Error bars indicate standard deviation. (B) Flow cytometry analysis of [Ca++]i release by Fluo3-am–loaded CTL stimulated for 1 minute at 37°C with PKH26-labeled target cells. Percentages correspond to CTL conjugates with calcium release of total CTLs. Target cell profile of LCL-7 alone is represented (left panel). (C) [Ca++]imeasurements were calculated from mean fluorescence values (see “Materials and methods”). Determination of [Ca++]i release by CTLs stimulated by RCC cells (left panel), LCL-6 or LCL-7, coated or not with mAbs (right panel).