Plasma Membrane and Cell Cortex Interactions in Lymphocyte Functions

Abstract

Surfaces of lymphocytes and macrophages in large part determine and control the multiplicity of cellular interactions that characterize immune function. The organization and physiology of cell surfaces are in turn determined by intrinsic plasma membrane markers and receptors and by the state of the underlying cell cortex, which contains the cytoskeleton and cytomusculature. This critical interrelationship between cell cortex and plasma membrane and its role in determining immunologic function are discussed in this chapter. Two general kinds of plasma membrane interactions are considered in detail. The first is an active process of motion and/or recognition initiated in the cortex and usually involving formation of uropode and microvilli where receptors are concentrated. The second is passive recognition in which resting lymphocytes are exposed to ligands that bind to and cluster receptors, thereby perturbing the cells' plasma membranes and initiating the biochemical events of activation. All factors that could interfere in one or another way with membrane organization could modulate cell activation but the most remarkable one is the stringent requirement for clustering shown by lectins and antibodies.