CD4 + c-Met + Itgα4 + T cell subset promotes murine neuroinflammation

Objective c-Met, a tyrosine kinase receptor, is the unique receptor for hepatocyte growth factor (HGF). The HGF/c-Met axis is reported to modulate cell migration, maturation, cytokine production, and antigen presentation. Here, we report that CD4 + c-Met + T cells are detected at increased levels in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS). Methods c-Met expression by CD4 + T cells was analyzed mostly by flow cytometry and by immunohistochemistry from mice and human PBMCs. The in vivo role of CD4 + c-Met + T cells was assessed in EAE. Results CD4 + c-Met + T cells found in the CNS during EAE peak disease are characterized by a pro-inflammatory phenotype skewed towards a Th1 and Th17 polarization, with enhanced adhesion and transmigration capacities correlating with increased expression of integrin α4 (Itgα4). The adoptive transfer of Itgα4-expressing CD4 + Vα3.2 + c-Met + T cells induces increased disease severity compared to CD4 + Vα3.2 + c-Met − T cells. Finally, CD4 + c-Met + T cells are detected in the brain of MS patients, as well as in the blood with a higher level of Itgα4. These results highlight c-Met as an immune marker of highly pathogenic pro-inflammatory and pro-migratory CD4 + T lymphocytes associated with neuroinflammation.