A fully human connective tissue growth factor blocking monoclonal antibody ameliorates experimental rheumatoid arthritis through inhibiting angiogenesis

Abstract

Background: Connective tissue growth factor (CTGF) plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA) by facilitating angiogenesis and is a promising therapeutic target for RA treatment. Herein, we generated a fully human CTGF blocking monoclonal antibody (mAb) through phage display technology. Results: A single-chain fragment variable (scFv) with a high affinity to human CTGF was isolated through screening a fully human phage display library. We carried out affinity maturation to elevate its affinity for CTGF and reconstructed it into a full-length IgG1 format for further optimization. Surface plasmon resonance (SPR) data showed that full-length antibody IgG mut-B2 bound to CTGF with a dissociation constant (KD) as low as 0.782 nM. In the collagen-induced arthritis (CIA) mice, IgG mut-B2 alleviated arthritis and decreased the level of pro-inflammatory cytokines in a dose-dependent manner. Furthermore, we confirmed that the TSP-1 domain of CTGF is essential for the interaction. Additionally, the results of Transwell assays, tube formation experiments, and chorioallantoic membrane (CAM) assays showed that IgG mut-B2 could effectively inhibit angiogenesis. Conclusion: The fully human mAb that antagonizes CTGF could effectively alleviate arthritis in CIA mice, and its mechanism is tightly associated with the TSP-1 domain of CTGF.