Innervation of the Immune System

This chapter examines the innervation of lymphoid tissues, and discusses its regulatory role in immunity. To better understand nerve-to-immune system pathways, the authors begin with a brief background on the peripheral nervous system as it relates to innervation of the immune system. Next, the innervation of primary and secondary lymphoid organs and mucosal-associated lymphoid tissue (MALT) is discussed. A brief description of the basic lymphoid organ structure and function precedes each section describing the innervation of each lymphoid tissue in order to provide the basic anatomy needed to understand the nerve distribution, and its importance in immune regulation. The major neurotransmitters of autonomic and sensory nerves colocalize with, and release other neuromediators that modulate the functions of the major neurotransmitters. Sympathetic noradrenergic (NA) nerves display plasticity - the ability of the brain or nerves to change structurally and/or functionally due to changes in the microenvironment.