Epstein-Barr virus promotes T cell dysregulation in a humanized mouse model of multiple sclerosis

Infection with the human-tropic Epstein-Barr virus (EBV) is a strong risk factor for multiple sclerosis (MS), though the underlying mechanisms remain unclear. To investigate the immunomodulatory effects of latent EBV infection, we induced experimental autoimmune encephalomyelitis (EAE) in immunocompromised mice humanized with peripheral blood mononuclear cells (PBMCs) from individuals with or without a history of EBV infection and/or a diagnosis of relapsing MS. HuPBMC EAE mice generated from EBV seronegative healthy donors were less susceptible to developing severe clinical disease than EBV seropositive healthy donor and RRMS cohorts. Donor EBV seropositivity and RRMS led to a significant incremental increase in the number of brain and spinal cord infiltrating effector T cells, in the absence of viral reactivation, due to enhanced proliferation of donor T cells and reduced regulatory T cell expansion. The data indicate that a history of EBV infection, further compounded by a diagnosis of RRMS, promotes T cell-mediated disease in a novel humanized mouse model of MS. SUMMARYIn a novel humanized mouse model of multiple sclerosis (MS), donor history of Epstein-Barr virus (EBV) infection exacerbates disease severity by skewing the balance of effector and regulatory T cells in the brain and spinal cord. These results reveal an immunomodulatory mechanism by which latent EBV infection could predispose to the development of autoimmune disease.