Figure 1

Effects of CB2 ligands on IL-6-induced IgM production in SKW6.4 cells. (A) IL-6, but not TPA or LPS, stimulated IgM secretion in a concentration dependent manner. SKW 6.4 cells were incubated for 4 days with the indicated concentrations of IL-6 (white bar), TPA (grey bar) or LPS (black bar). The secreted IgM was determined by ELISA. Background IgM secretion was 119 ng/ml and was subtracted from the IL-6-induced secreted IgM shown. (B) Expression of CB2 receptor in SKW 6.4 and human B malignancy myeloma cells MM1.S and U266. (C) Modulation of IL-6-induced IgM secretion by CB2 ligands. SKW 6.4 cells were incubated for 4 days with CB2 ligands (μM) plus IL-6 (100 U/ml in 0.04% DMSO). The secreted IgM was determined by ELISA. Background IgM secretion was 176 ng/ml and was subtracted from the IL-6-induced secreted IgM shown. Results were expressed as mean ± SD of three assays. (D) Effects of CB2 ligands on SKW6.4 cell proliferation. SKW 6.4 cells were incubated for 4 days with CB2 ligands plus IL-6 (100 U/ml in 0.04% DMSO). Cell DNA synthesis was determined with ³H-Thymidine uptake assay. (E) SKW6.4 cells were exposed to IL-6 (100 U/ml), SR144528 (0.1-10 μM) or vehicle control (0.05% DMSO, v/v) for 4 days. The untreated wells were used as control (Con). The secreted IgM was determined by ELISA. A representative experiment is shown. *P < 0.05 compared with IL-6 treatment alone.