NEUROTACTIN, A MEMBRANE-ANCHORED CHEMOKINE UP-REGULATED IN BRAIN INFLAMMATION

Chemokines are small secreted proteins that stimulate the directional migration of leukocytes and mediate inflammation(1-4). During screenin g of a murine choroid plexus complementary DNA library, we identified a new chemokine, designated neurotactin. Unlike other chemokines, neur otactin has a unique cysteine pattern, Cys-X-X-X-Cys, and is predicted to be a type 1 membrane protein. Full-length recombinant neurotactin is localized on the surface of transfected 293 cells. Recombinant neur otactin containing the chemokine domain is chemotactic for neutrophils both in vitro and in vivo. Neurotactin messenger RNA is predominantly expressed in normal murine brain and its protein expression in activa ted brain microglia is upregulated in mice with experimental autoimmun e encephalomyelitis, as well as in mice treated with lipopolysaccharid e. Distinct from all other chemokine genes, the neurotactin gene is lo calized to human chromosome 16q. Consequently we propose that neurotac tin represents a new delta-chemokine family and that it may play a rol e in brain inflammation processes.