Assessing the levels of CB1-R and CB2-R. (A) CEM, HEL-92 (HEL), and HL60 cell lines were cocultured with a biotinylated THC (at B_max concentration) and increasing concentrations of either the CB1-R or CB2-R antagonist (CB1-A or CB2-A). Mean fluorescence, as a measure of biotinylated THC binding, was then assessed by flow cytometry. (B) Similarly, the total cannabinoid-receptor level in each cell line was assessed by coculturing cells with biotinylated THC (Δ9-THC) and each antagonist (CB1-A and CB2-A); all were used at a maximum-blocking concentration. Each data point represents the mean of at least 3 separate experiments, and SDs have only been shown in panel B.