Chemokine and chemokine receptor expression in the central nervous system

A decade ago several new cytokines were described that orchestrated the act ivation and migration of immune cells. These newly described cytokines, of which interleukin-8 (IL-8) was a representative member, defined a novel gro up of molecules called chemokines (chemotactic cytokines). Chemokines are l ow molecular weight, 8-12 kDa, basic proteins that have been classified int o four distinct families, CXC, CC, C and CX3C, based on the position of the ir first two conserved cysteine residues. The expression and biological fun ction of chemokines along with their cognate receptors have been well descr ibed on various subsets of leukocytes. Only more recently have these molecu les been described on various cells within the central nervous system. Thes e proinflammatory proteins have been implicated in a variety of diseases wi thin the central nervous system from Multiple Sclerosis to AIDS dementia. W hile chemokines are likely to enhance the evolution of central nervous syst em inflammatory disorders they also have other roles in normal brain functi on and development. This review summarizes the role of chemokines and their receptors in the normal and pathophysiological brain.