J Immunol. 2004 Jan 1; 172(1): 550-9
Klein RS, Izikson L, Means T, Gibson HD, Lin E, Sobel RA, Weiner HL, Luster AD.
Center for Immunology and Inflammatory Diseases, Division of Rheumatology, Allergy and Immunology, Massachusetts General Hospital East, Harvard Medical School, Building 149, 13th Street, Charlestown, MA 02129, USA.
In multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), autoaggressive T cells traffic into the CNS and induce disease.
Infiltration of these pathogenic T cells into the CNS has been correlated with the expression of the chemokine IFN-inducible protein (IP)10/CXC chemokine ligand (CXCL)10, a chemoattractant for activated T cells, and its receptor CXCR3, in the CNS of both MS patients and mice with EAE.
In the present study, we report that targeted deletion of IP-10 did not diminish the expression, severity, or histopathology of EAE induced by active immunization with 100 micro g of myelin oligodendrocyte glycoprotein peptide (MOG)p35-55.
However, we found that IP-10-deficient mice had a lower threshold for expression of disease compared with wild-type littermates.
EAE induced by immunization with 5 micro g of MOGp35-55 resulted in more severe disease characterized by a greater number of CNS lesions and infiltrating mononuclear cells in IP-10-deficient mice compared with wild-type controls.
IP-10-deficient mice immunized with MOGp35-55 demonstrated increased levels of IFN-inducible T cell alpha-chemokine/CXCL11 mRNA in the CNS and decreased levels of monokine induced by IFN-gamma/CXCL9 mRNA in draining lymph nodes, suggesting differential compensation for loss of IP-10 in lymphoid vs parenchymal tissue compartments.
EAE in IP-10-deficient mice induced by low-dose immunization was associated with enhanced Ag-specific Th1 responses in the draining lymph node, which corresponded with diminished lymph node TGF-beta1 expression.
Our data demonstrated that IP-10 was not required for the trafficking of pathogenic T cells into the CNS in EAE but played an unexpected role in determining the threshold of disease susceptibility in the periphery.