Chapter 22 Early Gene Expression in the Activation of Mononuclear Phagocytes

Abstract

Publisher Summary This chapter discusses the current extent of information on early genes in macrophage activation. The activation of mononuclear phagocytes by various stimuli represents an excellent model for studying the regulation and function of early genes. Although mononuclear phagocytes (such as neutrophils) can be rapidly stimulated by chemotactic stimuli, such as formylated peptides or platelet activating factor (PAF), physiological activation with regard to macrophages is reserved for the development of increased competence to complete complex functions, such as the destruction of facultative-intracellular microorganisms or tumor cells. This activation, which is complexly regulated by multiple inductive and suppressive stimuli, requires ∼24 hrs for completion. Macrophage activation can be formally defined as the acquisition of competence to perform or complete a complex function, manifested by the altered expression of separate and independently regulated gene products. This may serve as a useful definition for cellular activation in general and, indeed, has been applied to the activation of endothelial cells.