Human monocyte-derived macrophages and dendritic cells as targets for biomaterial cytocompatibility studies using an improved in vitro culture system.
Since macrophage plays a key role in the biocompatibility process, neoplastic macrophage cell lines and human blood monocytes are commonly used as target cells for in vitro biomaterial tolerance evaluation. However, tumor cells profoundly differ from normal tissue cells and monocytes are only precursors of macrophages. It has become possible to generate recently, under adherent-free conditions, fully mature macrophages and dendritic cells from human blood monocytes in the presence of GM-CSF and GM-CSF + IL4 respectively. In the present work, we examined the effects of titanium-alloy on morphology, adhesion, cell phenotype and TNF-alpha release activity of such differentiated cells grown in hydrophobic teflon bags. Scanning electron microscopy showed that macrophages substantially adhered and spread on titanium-alloy surface throughout the culture period, whereas only a few dendritic cells were adherent. The phenotype of both cell types remained unchanged in the presence of the tested material. However, titanium-alloy stimulated the secretion of TNF-alpha by the macrophages of some donors. This model of culture may offer new insights into the biomaterial evaluation and may be useful for studying individual responses induced by biomaterials.