Factor-induced differentiation and activation of macrophages.

The cells of the mononuclear phagocyte lineage, namely monocytes and macrophages secrete over 50 proteins. This impressive versatility is regulated both internally, during the cells' maturation, and by events in the extracellular environment which activate the cells. Differentiation and activation are profoundly influenced by a variety of cytokines and these interactions were among the themes of a recently reported meeting.