Expression of IL-13 and response to IL-13 of the HL-derived cell line L-1236.

(A-B) Cytospin preparations of L-1236 cells were examined by in situ hybridization with antisense (A) and sense (B) probes for IL-13 (original magnifications, × 1400). Black-colored silver grains denote mRNA expression. IL-13⁺ cells were detected with the antisense probe, whereas no signal was obtained with the control sense probe. (C-D) HL-derived cell lines L-1236 (●) and L-540 (○) and control LCL-GK (▾) cells were treated with either 20 μg/mL anti–IL-13 antibody (C) or 20 μg/mL of an isotype control (D). Proliferation was measured at 24, 48, and 72 hours by [³H]-thymidine incorporation. The y-axis shows the proliferation of the treated cells as a percentage of the corresponding untreated control, calculated as the mean of triplicate samples. (E) L-1236 cells were treated with various doses of anti–IL-13 antibody and [³H]-thymidine incorporation was measured at 72 hours. The value of 56 446 cpm (untreated control at 72 hours) was taken as 100% proliferation. (F) L-1236 cells were treated with various doses of exogenous IL-13 and [³H]-thymidine incorporation was measured at 48 hours. The value of 34 688 cpm (untreated control at 48 hours) was taken as 100% proliferation. These experiments were repeated twice with similar results.