It also is a marker of cells from the monocyte/macrophage lineage. Lesser doses can be prescribed in order to achieve suppression of monocyte function. Macrophages can be activated to perform functions that a resting monocyte cannot. These MGCs are cells of monocyte or macrophage lineage fused together. "GEMM" stands for granulocyte, erythrocyte, monocyte, megakaryocyte. Like other MGCs they are formed from the fusion of Monocyte/Macrophage precursors. It readily invades and multiplies in a wide variety of fibroblast and monocyte cell lines. Breakdown is responsible for monocyte infiltration and inflammation in the brain. Neutrophils are much more numerous than the longer-lived monocyte/macrophage phagocytes. Osteoclasts also arise from hemopoietic cells of the monocyte/neutrophil lineage, specifically CFU-GM. The source for histiocytes is the monocyte/macrophage line. Similar to their monocyte precursors, they are able to phagocytose foreign materials. Thrombomodulin is also expressed on human mesothelial cell, monocyte and a dendritic cell subset. White blood cells of the monocyte/macrophage lineage are the main target of visna virus. CCL2 augments monocyte anti-tumor activity and it is essential for formation of granulomas.