Structural insights into a human anti-IFN antibody exerting therapeutic potential for systemic lupus erythematosusOuyang, S., Gong, B., Li, J.-Z., Zhao, L.-X., Wu, W., Zhang, F.-S., Sun, L., Wang, S.-J., Pan, M., Li, C., Liang, W., Shaw, N., Zheng, J., Zhao, G.-P., Wang, Y., Liu, Z.-J., Liang, M.-F.
(2012) J.Mol.Med. --: --
- PubMed: 22307521
- DOI: 10.1007/s00109-012-0866-3
- PubMed Abstract:
Increasing evidences suggest that the type I interferon α (IFN α) plays a critical role in the etiopathogenesis of systemic lupus erythematosus (SLE), which makes it a promising therapeutic target for the treatment of the disease. By screening a larg ...
Increasing evidences suggest that the type I interferon α (IFN α) plays a critical role in the etiopathogenesis of systemic lupus erythematosus (SLE), which makes it a promising therapeutic target for the treatment of the disease. By screening a large size non-immune human antibody library, we have developed a human single-chain antibody (ScFv) AIFN α 1bScFv01 and corresponding whole antibody AIFN α 1bIgG01 to human interferon α 1b (IFN α 1b) with high specificity and high affinity. The IgG antibody could down-regulate the expression of ISG15 and IFIT-1 induced by either recombinant IFN α 1b or naïve IFN α from SLE patients' sera, and reduced total serum IgG and IgM antibodies level in a pristane-primed lupus-like mouse model. The crystal structure of AIFN α 1bScFv01-IFN α 1b complex solved to 2.8 Å resolution revealed that both Pro26-Gln40 region in loop AB and Glu147-Arg150 region in helix E of IFN α 1b contribute to binding with AIFN α 1bScFv01. Four residues of above two regions (Leu30, Asp32, Asp35 and Arg150) are critical for the formation of antigen-antibody complexes. AIFN α 1bScFv01 shares partial epitopes of IFN α 1b with its receptor IFNAR2 but with much higher binding affinity to IFN α 1b than IFNAR2. Thus, AIFN α 1bIgG01 exhibits its neutralizing activity through competition with IFNAR2 to bind with IFN α and prevents the activation of IFN α-mediated signaling pathway. Our results highlight the potential use of the human antibody for modulating the activity of IFN α in SLE.
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.