Efficacy of novel bispecific antibody targeting TNF-α/CXCL10 in the treatment of experimental arthritis

Abstract

This study was aimed at generating and investigating the efficacy of a novel monoclonal bispecific antibody (BsAb) for the combined inhibition of tumor necrosis factor-α (TNF-α) and CXCL10 as a treatment option for rheumatoid arthritis (RA). A novel BsAb targeting TNF-α and CXCL10 was generated by conjugating a single-chain variable fragment (scFv) of the anti-CXCL10 monoclonal antibody to the Fc region of adalimumab (ADA). The effects of the BsAb on the inflammatory response in the in vitro and in vivo development of arthritis and joint destruction were evaluated in human TNF transgenic (hTNF-Tg) mice, and K/BxN serum transfer arthritis models. The BsAb inhibited CXCL10-mediated CD8⁺ T cell migration. The binding affinity of the BsAb to TNF-α was comparable to that of ADA and suppressed TNF-α induced cell death and inhibited TNF-α induced ICAM-1 and VCAM-1 in RA fibroblast-like synoviocytes (FLSs). The BsAb decreased the expression of TNFSF11 and the production of IL-6 in RA-FLS cells stimulated with TNF-α and CXCL10. Treatment with the BsAb attenuated the development of arthritis in hTNF-Tg mice and suppressed LPS-induced bone erosion. In the K/BxN serum transfer model, BsAb effectively attenuated ankle swelling, synovial inflammation, cartilage damage, and bone destruction, reducing the activation of osteoclasts. The additional neutralization of TNF-α and CXCL10 from treatment with the novel BsAb was more effective than TNF-α inhibition alone in the in vitro and in vivo models of RA. Thus, the BsAb, targeting both TNF-α and CXCL10, may provide a new therapeutic opportunity for RA patients who fail to respond to the blockade of a single cytokine.

Keywords: ADA = adalimumab; ANOVA = analysis of variance; BsAb = bispecific antibody; CXCL10 = C-X-C motif chemokine 10; FLS = fibroblast-like synoviocytes; GAPDH = glyceraldehyde 3-phosphate dehydrogenase; H&E = hematoxylin and eosin; IC(50) = the half-maximal inhibitory concentration; IL = interleukin; Kd = dissociation constants; LPS = lipopolysaccharide; Mw = molecular weight; O.D. = optical density; PBMCs = peripheral blood mononuclear cells; PBS = phosphate-buffered saline; RANKL = receptor activator of nuclear factor kappa-B ligand; RA = rheumatoid arthritis; SEM = standard error of the mean; SPR = surface plasmon resonance; ScFv = single-chain variable fragment; TNF-α = tumor necrosis factor-α; TRAP = tartrate-resistant acid phosphatase; Tg mouse = transgenic mouse; VH = variable heavy chain; VL = variable light chain; bDMARDs = biological disease-modifying anti-rheumatic drugs; cDNA = complementary DNA; qPCR = quantitative real-time polymerase chain reaction.