The bispecific antibody aimed at the vicious circle of IL-1β and IL-17A, is beneficial for the collagen-induced rheumatoid arthritis of mice through NF-κB signaling pathway.

Rheumatoid arthritis (RA) is a chronic, systemic and autoimmune disease with overexpression inflammation cytokines. The biological therapy targeting these inflammatory cytokines has been applied for the clinic. Drugs aimed at a single target are ineffective in some patients with RA. However, double-target and multi-target drugs have huge advantages in therapy. Interleukin-1β (IL-1β) and Interleukin-17A (IL-17A) are the keys to inflammatory factors in RA. The bispecific antibody(BsAb)against both human IL-1β and human IL-17A was formed and expressed in E. coli. The binding specificity and efficiency of the BsAb was tested by enzyme-linked immunosorbent assay, Western blotting and several cells experiments including THP-1, 3T3-L1 and L929 in vitro. Different doses of BsAb (5, 2, 0.8mg/kg) were compared in collagen-induced arthritis (CIA) mice, with Adalimumab and Dexamethasone as the positive control. The effects on mice were determined by the degree of arthritis severity, cytokines levels, the level of IgG against CII and rheumatoid factor level in serum, the transcription levels of relative cytokines in the spleen, and histological damage. Furthermore, the activation of NF-κB was analyzed by Western blotting. In conclusion, BsAb can bind with IL-1β and IL-17A to alleviate the severity of arthritis, to decrease the levels of inflammation cytokines in serum, to down-regulate the expression of IL-1β, IL-2, IL-6, IL-17A, TNF-α, IFN-γ, and MMP-3, to up-regulate the expression of IL-10, to relieve histological damage and to inhibit bone destruction. BsAb inhibited nuclear translocation of the p65 subunit and cytoplasm IκB-α degradation by blocking IL-1β and IL-17A, the upstream of NF-κB pathway. High doses of BsAb had a more beneficial effect on CIA mice than Adalimumab and Dexamethasone. Thus, these results indicate that BsAb can be regarded as an ideal candidate for RA therapy.