Human respiratory syncytial virus and Th1 chemokines

The importance of the Type-1 helper (Th1) chemokines in RSV (respiratory syncytial virus) infection has been shown by several studies, in animal models, and in humans. The production of Th1 chemokines within the lower respiratory tract has been shown in patients with RSV bronchiolitis, particularly chemokine (C-X-C motif) ligand (CXCL)10/interferon-γ-inducible protein 10 (IP-10), whose plasma levels were markedly elevated in acute infection. RSV fusion (F) or large (G) protein treatment of fully differentiated primary normal human bronchial epithelial cells induces apical secretion of IP-10 and other chemokines. Exposure to environmental tobacco smoke is associated with an increase in the frequency and severity of respiratory infections, including bronchiolitis, and inhibited RSV-induced Interferon (IFN)-α in plasmacytoid dendritic cells as well as the release of IP-10. Vitamin D in airway epithelium decreases RSV induction of NF-kappaB-driven genes such as IFN-β and IP-10. These findings highlight the role for the IP-10: chemokine (C-X-C motif) receptor (CXCR)3 signaling axis in RSV-infection by recruiting virus-specific T cells into the lung and promoting viral clearance.