Expression data from cortical tissue of 5XFAD mice treated with 5B8 antibody or IgG control

Activation of innate immunity and deposition of blood-derived fibrin in the central nervous system (CNS) occur in autoimmune and neurodegenerative diseases, including multiple sclerosis (MS) and Alzheimer’s disease (AD). However, mechanisms linking blood-brain barrier (BBB) disruption with neurodegeneration are poorly understood, and exploration of fibrin as a therapeutic target has been limited by its beneficial clotting functions. Here we report the generation of monoclonal antibody 5B8 targeted against the cryptic fibrin epitope γ377-395 to selectively inhibit fibrin-induced inflammation. 5B8 suppressed fibrin-induced proinflammatory gene expression, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, and oxidative stress. In animal models of MS and AD, 5B8 entered the CNS and bound to parenchymal fibrin, and its therapeutic administration reduced innate immune activation and neurodegeneration without interfering with clotting. Thus, fibrin-targeting immunotherapy inhibits autoimmune- and amyloid-driven neurotoxicity and may have clinical benefit without globally suppressing innate immunity or interfering with coagulation in diverse neurological diseases. Cortical tissue was isolated from brains of 5XFAD mice following two months of i.p. injection every other day with 5B8 antibody or control IgG antibody beginning at 3 months of age. RNA was extracted and subsequently processed for hybridization on Affymetrix microarrays. Gene expression data were adjusted for background and normalized using RMA.