Chapter category: Viruses
CX3C Chemokine Mimicry by Respiratory Syncytial Virus G Glycoprotein
Chapter authors:
Ralph A. Tripp
Chemokines are small disulphide-linked polypeptides that act as potent chemoattractants for many cell types including lymphocytes, monocytes, macrophages, neutrophils and NK cells. As described in chapter 1 chemokines are divided into subfamilies based upon cysteine signature motifs termed C, CC, CXC and CX3C and have roles in immunity and inflammation affecting cell trafficking and activation. The only described CX3C chemokine is fractalkine, an unusual chemokine in that it exists both as a membrane bound protein and as a cleaved soluble molecule. Several viruses have evolved strategies to alter immune responses by expressing proteins that mimic chemokines or their receptors. The G glycoprotein of respiratory syncytial virus (RSV) was recently shown to contain a CX3C chemokine motif that competes with fractalkine for binding to its receptor, CX3CR1, induces fractalkinelike leukocyte chemotaxis, and facilitates virus infection. The implications of this finding in the biology of RSV infection and disease pathogenesis are discussed.
