Differential chemotactic responsiveness of monocyte subsets to pCCL2. (A) Isolated monocytes were subjected to chemotaxis induced by CCL2 or kept under identical conditions (input) for 3 h. Input cells (1), cells that did not migrate (2) or cells that migrated (3) were recovered and the expression of Tük4 and SLA II analysed by two-colour flow cytometry. Dot plots correspond to a representative experiment out of four performed. (B) Isolated monocytes were cultured for 3 h in Teflon containers in the presence of supernatants of CHO cells transfected with pCCL2-GFP or InvCCL2-GFP, and the expression of Tük4 and SLA-II analysed by two colour flow cytometry. 10 000 cells were acquired.