IC100: a novel anti-ASC monoclonal antibody improves functional outcomes in an animal model of multiple sclerosis

Background: The inflammasome adaptor apoptosis-associated speck-like protein containing a CARD (ASC) is involved in immune signaling by bridging the interactions between inflammasome sensors and Caspase-1. Strong experimental evidence has shown that ASC^-/- mice are protected from disease progression in animal models of multiple sclerosis (MS), suggesting that targeting inflammasome activation via ASC inhibition may be a promising therapeutic strategy in MS. Thus, the goal of our study is to test the efficacy of IC100, a novel humanized antibody targeting ASC, in preventing and/or suppressing disease in the experimental autoimmune encephalomyelitis (EAE) model of MS.

Methods: We employed the EAE model of MS where disease was induced by immunization of C57BL/6 mice with myelin oligodendrocyte glycoprotein peptide 35-55 (MOG_35-55). Mice were treated with vehicle or increasing doses of IC100 (10, 30, and 45 mg/kg) and clinical disease course was evaluated up to 35 days post EAE induction. Immune cell infiltration into the spinal cord and microglia responses were assessed.

Results: We show that IC100 treatment reduced the severity of EAE when compared to vehicle-treated controls. At a dose of 30 mg/kg, IC100 significantly reduced the number of CD4⁺ and CD8⁺ T cells and CD11b⁺MHCII⁺ activated myeloid cells entering the spinal cord from the periphery, and reduced the number of total and activated microglia.

Conclusions: These data indicate that IC100 suppresses the immune-inflammatory response that drives EAE development and progression, thereby identifying ASC as a promising target for the treatment of MS as well as Other neurological diseases with a neuroinflammatory component.

ASC; Caspase-1; Experimental autoimmune encephalomyelitis; IC100; IL-1; Inflammasome; Multiple sclerosis; Neuroinflammation; Pycard.