FN30-Fc

FN30-Fc is a recombinant fusion protein consisting of the N-terminal 30-kDa module of fibronectin (FN30) fused to an immunoglobulin Fc fragment. It is designed to act as a decoy or blocking agent that interrupts the interaction between fibronectin and the immune checkpoint receptor Leukocyte Immunoglobulin-Like Receptor B4 (LILRB4), also known as ILT3 in humans or gp49B in mice. By blocking this interaction, FN30-Fc modulates B cell activation and class switch recombination, leading to a reduction in the production of pathogenic IgG autoantibodies. In preclinical models of systemic lupus erythematosus (SLE), specifically BXSB/Yaa mice, treatment with FN30-Fc has demonstrated the ability to ameliorate autoimmune glomerulonephritis and reduce glomerular deposition.