Sema4A inhibits the therapeutic effect of IFN-β in EAE

Approximately one-third of patients with multiple sclerosis (MS) respond poorly to interferon-beta (IFN-β) therapy. Serum Sema4A is increased in MS patients, and those who have high Sema4A do not respond to IFN-β therapy. In this study, we investigated whether recombinant Sema4A abrogates the efficacy of IFN-β in mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Administration of Sema4A concurrently with IFN-β diminished the efficacy of IFN-β in EAE. These effects of Sema4A were attributed to promote Th1 and Th17 differentiation and to increase adhesive activation of T cells to endothelial cells, even in the presence of IFN-β.