Reciprocal regulation of the neural and innate immune systems

Abstract

Have you ever wondered about the underlying mechanism of why you become lethargic when you have an infection, and why you are more susceptible to infection during times of stressful life circumstances? Here, the reciprocal interactions between behaviour and innate immunity to optimize total organism fitness are discussed. Innate immune responses are regulated by microorganisms and cell death, as well as by a third class of stress signal from the nervous and endocrine systems. The innate immune system also feeds back, through the production of cytokines, to regulate the function of the central nervous system (CNS), and this has effects on behaviour. These signals provide an extrinsic regulatory circuit that links physiological, social and environmental conditions, as perceived by the CNS, with transcriptional 'decision-making' in leukocytes. CNS-mediated regulation of innate immune responses optimizes total organism fitness and provides new opportunities for therapeutic control of chronic infectious, inflammatory and neuropsychiatric diseases.