Innate immunity is triggered by two types of signal from the body’s internal environment: pathogen-associated molecular patterns (PAMPs) and ‘danger signals’ derived from stress or death of the host cell.
In this recent perspective, Michael Irwin and Steven Cole from the Cousins Center for Psychoneuroimmunology discuss a third class of stimulus, in the form of neural and endocrine signals, resulting from macroenvironmental sensing, and its involvement in the reciprocal regulation of neural–immune circuits. The authors highlight some emerging views on the interactions between the ‘extrinsic’ central nervous system (CNS)– leukocyte–CNS regulatory circuit and the immunological ‘intrinsic’ microorganism–leukocyte– microorganism circuit, in the context of microorganismal, macroorganismal and ecological regulatory loops. They suggest that the ‘extrinsic’ regulation by the CNS can either globally suppress immune response gene transcription or steer immune response gene transcriptional profiles away from antiviral programs and towards more robust pro-inflammatory gene expression. The authors point out new therapeutic approaches for inflammatory diseases and discuss the evolutionary basis for the emergence of a third CNS-derived signal, one that controls immune responses.
SOURCE: Nat Rev Immunol 2011, 11:625