Expression and Modulation of IFN- γ -Inducible Chemokines (IP-10,Mig,and I-TAC) in Human Brain Endothelium and Astrocytes: Possible Relevance for the Immune Invasion of the Central Nervous System and the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS) mediated by blood-derived immune cells invading the CNS. This invasion could be determined by chemokines, and their role within the MS-affected brain is still poorly defined. We investigated the expression by RT-PCR and protein release by ELISA of the interferon-γ (IFN-γ)-inducible chemokines in human brain microvascular endothelial cells (HBMECs) and astrocytes. The monokine induced by IFN-γ (Mig) behaves as a homing chemokine constitutively expressed in HBMECs and astrocytes, whereas the IFN-γ-inducible 10-kDa protein (IP-10) and IFN-inducible T cell alpha-chemoattractant (I-TAC) are induced only after inflammatory stimuli. The biologic activity of IFN-γ-inducible chemokines from an endothelial source was analyzed, and the transendothelial migration of activated lymphocytes was partly antagonized by specific antibodies, especially anti-Mig antibody. Our data highlight the capability of cells of the CNS to activate the chemoattractant machinery in a proinflammatory environment and in MS.