FIGURE 6.

CD300b acts as a modifier of CD300c signaling. A, RBL-2H3 cells stably expressing CD300c-Myc on the cell surface were transfected with CD300b-HA or CD300b ΔIg-HA. Cell surface expression of the different transfectants was checked by flow cytometry using anti-Myc9E10 for CD300c (light gray histogram) and anti-HA12CA5 mAb for CD300b (dark gray histogram). Isotypic mAb was used as negative control (black histogram). B and D, RBL-2H3 transfectants were transiently transfected with 3×NFAT/AP1-Luciferase and TK-Renilla plasmids. Luciferase activity was measured after stimulation for 7 h with the indicated antibodies. Data were normalized as described before. Duplicates were performed for all stimulations. Results are representative of five independent experiments. C, RBL-2H3 transfectants were stimulated with the indicated Abs for assessing hexosaminidase granule release. Data are expressed as a percentage of specific release. Each stimulation point was set up in triplicate. The result is a mean of three independent experiments (*, p ≤ 0.05; **, p ≤ 0.01). N.S., non-significant. Error bars represent standard deviation.