ADHESION MOLECULE EXPRESSION AND RESPONSE TO CHEMOTACTIC AGENTS OF HUMAN MONOCYTE-DERIVED MACROPHAGES

Human monocyte-derived macrophages have been proposed as agents of ant i-tumour immunotherapy. The aim of the present study was to investigat e in vitro the properties of these cells likely to control their recru itment to the sites of inflammation and tumours. The expression of adh esion molecules involved in the binding of monocytes to endothelial ce lls was modified during monocyte-macrophage differentiation, with a si gnificant increase in CD11c, CD14 and intercellular adhesion molecule- 1 (ICAM-1). Monocyte-derived macrophages were sensitive to chemoattrac tants, in particular to the monocyte-specific chemokine monocyte chemo tactic protein-1 (MCP-1). They responded by an increased expression of adhesion molecules and were attracted by the cytokine in an under-aga rose migration assay. The migration response, however, decreased after days 4-5 of monocyte differentiation into macrophage. In conclusion, human monocyte-derived macrophages show alterations of surface structu res involved in the recognition of inflammatory endothelium. This may explain why the cells are poorly recruited to the sites of inflammatio n and tumours when introduced into the circulation.