Consistent induction of chronic experimental autoimmune encephalomyelitis in C57BL/6 mice for the longitudinal study of pathology and repair

Abstract

Background: While many groups use experimental autoimmune encephalomyelitis (EAE) as a model to uncover therapeutic targets and understand the pathology underlying multiple sclerosis (MS), EAE protocol variability introduces discrepancies in central nervous system (CNS) pathogenesis and clinical disease, limiting the comparability between studies and slowing much-needed translational research.

Optimized method: Here we describe a detailed, reliable protocol for chronic EAE induction in C57BL/6 mice utilizing two injections of myelin oligodendrocyte glycoprotein (35-55) peptide mixed with complete Freund's adjuvant and paired with pertussis toxin.

Results: The active MOG_35-55-EAE protocol presented here induces ascending paralysis in 80-100% of immunized mice. We observe: (1) consistent T cell immune activation, (2) robust CNS infiltration by peripheral immune cells, and (3) perivascular demyelinating lesions concurrent with axon damage in the spinal cord and various brain regions, including the optic nerve, cortex, hippocampus, internal capsule, and cerebellum.

Comparison with existing method(s): Lack of detailed protocols, combined with variability between laboratories, make EAE results difficult to compare and hinder the use of this model for therapeutic development. We provide the most detailed active MOG_35-55-EAE protocol to date. With this protocol, we observe high disease incidence and a consistent, reliable disease course. The resulting pathology is MS-like and includes optic neuritis, perivascular mononuclear infiltration, CNS axon demyelination, and axon damage in both infiltrating lesions and otherwise normal-appearing white matter.

Conclusions: By providing a detailed active MOG_35-55-EAE protocol that yields consistent and robust pathology, we aim to foster comparability between pre-clinical studies and facilitate the discovery of MS therapeutics.

Keywords: Autoimmune; Brain; Clinical score; Demyelination; Experimental autoimmune encephalomyelitis (EAE); Immune cells; Immunohistochemistry; Infiltration; Inflammatory cells; MOG(35-55); Mouse models of multiple sclerosis; Multiple sclerosis (MS); Myelin basic protein; Neurodegeneration; Pertussis toxin; Spinal cord.