Conclusions
We used phage display to screen C5B3 against C5, which was effective in inhibiting cytotoxicity in vitro and preventing CNS pathology in vivo.
Methods
After 5 rounds of phage display, we isolated individual clones and identified phage clones specifically binding to C5 using ELISA. Using aquaporin-4 (AQP4)-transfected cells in vitro, we confirmed whether these scFvs prevented complement-dependent cytotoxicity (CDC) caused by the serum of patients with NMOSD and human complement (hC). We selected an NMOSD mouse model, in which intracerebral NMOSD immunoglobulin G (IgG) and hC injections induce NMOSD-like lesions in vivo.
Objective
Using phage display, we sought to screen single-chain variable fragments (scFvs) against complement C5 to treat neuromyelitis optica spectrum disorder (NMOSD).
Results
We obtained scFvs to test specificity and blocking efficiency. The scFv C5B3 neutralized C5 in the complement activation pathway, which prevented AQP4-IgG-mediated CDC in AQP4-transfected cells. In an NMOSD mouse model, C5B3 prevented AQP4 and astrocyte loss, decreased demyelination, and reduced inflammatory infiltration and membrane attack complex formation in lesions. Conclusions: We used phage display to screen C5B3 against C5, which was effective in inhibiting cytotoxicity in vitro and preventing CNS pathology in vivo.