Experimental Autoimmune Encephalomyelitis (EAE) Model

 

Experimental Autoimmune Encephalomyelitis (EAE) is a relevant preclinical model of multiple sclerosis (MS). MS is a central nervous system chronic inflammatory disease which leads to brain inflammation and demyelination. MS is considered an autoimmune disorder caused by auto-reactive T cells with symptoms including muscle stiffness and paralysis, visual disturbances and blindness, sensory loss, and ataxia. The disease is prone to relapse and remission. There are several different animal models of MS. EAE is widely used model for MS due to similar pathological features of inflammation and demyelination. Among factors that influence the disease, the IL-23/IL-17 axis has been implicated in the pathogenesis of EAE and MS1-3.

EAE can be induced by immunization with the proteins derived from the myelin sheath, such as myelin-oligodendrocyte glycoprotein (MOG), and Complete Freund’s Adjuvant (CFA) accompanied by an intraperitoneal injection of pertussis toxin (PTX) on the day of immunization and two days later. Myelin specific T cells are activated in the periphery, migrate through the blood-brain barrier into the CNS and are reactivated, triggering a series of inflammatory reactions that lead to demyelination and axon cell death, and ultimately to nerve injury and disability. Clinical symptoms are assessed using a standard scoring system that measures the degree of disease induction. Local demyelination and Inflammatory leukocyte infiltration can be visualized by histopathological staining. Biocytogen provides a robust MOG-induced EAE model for efficacy studies. In particular, we generated B-hIL17A mice where the human IL-17A gene is knocked-in and replaces the mouse IL-17A gene, thus providing a genetically humanized mouse EAE model for convenient testing of MS therapeutics targeting the human IL-17A.

Generation of B-hIL17A Mice and its phenotypic analysis

Schematic-of-EAE-Model

Experimental Autoimmune Encephalomyelitis (EAE) is an induced demyelinating disease model that closely resembles the progression and symptoms of the human neurological disease Multiple Sclerosis (MS).

Clinical score of EAE model

Clinical-Score-of-EAE-Model

EAE induction by MOG35–55/CFA Emulsion PTX in 10-week-old B-hIL17A mice (female). Data are expressed as mean ± SEM from a typical experiment (n = 5). MOG: myelin-oligodendrocyte glycoprotein; PTX: pertussis toxin.

Generation of MS/EAE Model and its phenotypic analysis

H&E and IHC staining in mouse EAE model

H-E-and-IHC-Straining-1

HE staining showing lumbar enlargement, 4x. Inset 20x.

H-E-and-IHC-Straining-2

Immunofluorescence (IF) staining of lumbar. Green, MBP; Blue, DAPI. Sections: 4x. Inset: 20x.

Local inflammation of the CNS in B-hIL17A mice (female, n=5) during EAE. On day 45 after MOG/CFA and PTx immunization, spinal cords were removed. The tissue sections were stained with H&E(A,B) and IHC (C,D)(Green, MBP; Blue, DAPI). The sections at the lumbar level are shown. The results showed that the infiltration of inflammatory cells in the MOG group was significantly increased, and the myelin protein was greatly reduced.

Increase of IL-17A+ cells in lymph node of EAE model

Increase-of-IL-17A

IL-17 is primarily produced by CD4 Th17 cells during the development of EAE. To detect IL-17 production, cells from lymph node of B-hIL17A mice (female, n=5) immunized with MOG/CFA were stimulated for 6 hours by PMA and ionomycin in the presence of brefeldin A. IL-17-producing cells were analyzed by FACS, along with IFN-gamma. The percentage of IL-17+CD3+CD4+ T cells in CD3+CD4+ T cells was increased in response to MOG immunization in B-hIL17A mice (left panel).  So was the percentage of IFN-gamma T cells.

Increase of  IL-17A+ cells in CNS of EAE model

Increase-of-IL-17A Increase-of-IL-17A-CNS

CNS (brain) cells of B-hIL17A mice (female, n=5)  immunized with MOG/CFA were stimulated for 6 hours by PMA and ionomycin in the presence of brefeldin A. IL-17-producing cells were analyzed by FACS, along with IFN-gamma. The percentage of IL-17+CD3+CD4+ T cells in CD3+CD4+ T cells was increased in response to MOG immunization in B-hIL17A mice (left panel).  So was percentage of IFN-gamma T cells.

Reference:

[1] Iwakura Y, Ishigame H. The IL-23/IL-17 axis in inflammation.J Clin Invest. 2006 May;116(5):1218-22.

[2] Gaffen SL,et al., The IL-23-IL-17 immune axis: from mechanisms to therapeutic testing. Nat Rev Immunol. 2014 Sep;14(9):585-600. doi: 10.1038/nri3707.

[3] Kuwabara T,et al., The Role of IL-17 and Related Cytokines in Inflammatory Autoimmune Diseases. Mediators Inflamm. 2017;2017:3908061.

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