Bs: pre-incubate the cells with 0.5 g of mAb 2.4G2 (anti-mouse CD16/CD32, to block binding of FcR) per million cells for 5?0 minutes on ice prior to staining, then add 0.25 g/ml of FITC-labeled anti-mouse F4/80 or FITC-labeled anti-mouse CD11b to the cells in each tube, mix gently and incubate for 30 min in the dark. All staining procedures were carried out at 4 . Cells were then washed 3 times an