CXCL10 and trafficking of virus-specific T cells during coronavirus-induced demyelination

Chronic expression of CXC chemokine ligand 10 (CXCL10) in the central nervous system (CNS) following infection with the neurotropic JHM strain of mouse hepatitis virus (JHMV) is associated with an immune-mediated demyelinating disease. Treatment of mice with anti-CXCL10 neutralizing antibody results in limited CD4+ T cell infiltration into the CNS accompanied by a reduction in white matter damage. The current study determines the antigen-specificity of the T lymphocytes present during chronic disease and evaluates how blocking CXCL10 signaling affects retention of virus-specific T cells within the CNS. CXCL10 neutralization selectively reduced accumulation and/or retention of virus-specific CD4+ T cells, yet exhibited limited effect on virus-specific CD8+ T cells. The response of CXCL10 neutralization on virus-specific T cell subsets is not due to differential expression of the CXCL10 receptor CXCR3 on T cells as there was no appreciable difference in receptor expression on virus-specific T cells during either acute or chronic disease. These findings emphasize the importance of virus-specific CD4+ T cells in amplifying demyelination in JHMV-infected mice. In addition, differential signals are required for trafficking and retention of virus-specific CD4+ and CD8+ T cells during chronic demyelination in JHMV-infected mice.