Age-related macular degeneration (AMD) is one of the main causes of visual impairment in adults. Visual deterioration is more prominent in neovascular AMD with choroidal neovascularization (CNV). Clinical and postmortem studies suggested that complement system activation might induce CNV. In this study, we demonstrated that an anti-mouse complement component 5 (C5) antibody targeting MG4 domain of β chain effectively inhibited CNV which was induced by laser photocoagulation in mice. The targeted epitope of this anti-C5 antibody was different from that of currently utilized anti-C5 antibody (eculizumab) in the MG7 domain in which a single nucleotide polymorphism (R885H/C) results in poor response to eculizumab. Even with targeting MG4 domain, this anti-C5 antibody reduced production of C5a, monocyte chemoattractant protein-1 and vascular endothelial growth factor to prevent infiltration of F4/80-positive cells into CNV lesions and formation of CNV. Furthermore, anti-C5 antibody targeting MG4 domain induced no definite toxicity in normal retina. These results demonstrated that anti-C5 antibody targeting MG4 domain inhibited CNV in neovascular AMD.
Keywords: MG4 domain; age-related macular degeneration; choroidal neovascularization; complement component 5; therapeutic antibody.