One easy way to remove NK cells and monocytes is to incubate with leucyl leucyl methyl ester (LLME) and leucyl methyl ester (LME). The compounds cause quite specific lysis of NK cells and monocytes without doing anything to T-cells and B-cells. They were described by Lipsky's group. Josiah Wedgwood (wedgwood at msvax.mssm.edu)