Chemokines and their receptors in neurobiology: perspectives in physiology and homeostasis.

Chemokines are a large family of small secreted proteins (8-14 kDa) associated with the trafficking of leukocytes in physiological immunosurveillance as well as inflammatory cell recruitment in different disease processes. A limited repertoire of chemokines and their specific cognate receptors are detectable in cells of the CNS such as microglia, astrocytes and neurons under physiological conditions. Coupled with distinct patterns of ligand and receptor expression in various pathologies including multiple sclerosis, trauma, neuro-AIDS, Alzheimer's disease, stroke, neuro- and glioblastomas, such phenomena have fueled the strong belief that chemokines must fulfill significant and potentially diverse functional roles in the CNS.