CB2 agonist reverses the inhibitory effect of SR144528 on IL-6-induced IgM secretion. SKW 6.4 cells were exposed to CB2 selective agonist HU308 (5 μM), SR144528 (10 μM) or their combination for 4 days in the presence of IL-6 (100 U/ml). IgM in the culture supernatants was measured by ELISA. Background IgM secretion was 126 ng/ml and was subtracted from the IL-6-induced secreted IgM shown. Results were expressed as mean ± SD of three assays. *P < 0.05 compared with the control (IL-6 treated alone).