Comparison of the Inhibition Mechanisms of Adalimumab and Infliximab in Treating Tumor Necrosis Factor α-Associated Diseases from a Molecular View

Abstract

Background:The epitope and the TNF␣ inhabitation mechanism of Adalimumab remain unclear. Results: The crystal structure of the TNF␣ in complex with Adalimumab is reported at a resolution of 3.1 Å. Conclusion:The epitope of Adalimumab provided information that Adalimumab may have clinical advantage compared with Infliximab. Significance: These data reveal the Adalimumab's mechanism of TNF␣ inhibition and its advantages compared with other TNF inhibitors in clinical practice. TNF␣-targeting therapy with the use of the drugs Etanercept, Infliximab, and Adalimumab is used in the clinical treatment of various inflammatory and immune diseases. Although all of these reagents function to disrupt the interaction between TNF␣ and its receptors, clinical investigations showed the advantages of Adalimumab treatment compared withEtanercept and Infliximab. However, the underlying molecular mechanism of action of Adalimumab remains unclear. In our previous work, we presented structural data on how Infliximab binds with the E-F loop of TNF␣ and functions as a TNF␣ receptorbinding blocker. To further elucidate the variations between TNF␣ inhibitors, we solved the crystal structure of TNF␣ in complex with Adalimumab Fab. The structural observation and the mutagenesis analysis provided direct evidence for identifying the Adalimumab epitope on TNF␣ and revealed the mechanism of Adalimumab inhibition of TNF␣ by occupying the TNF␣ receptor-binding site. The larger antigenantibody interface in TNF␣ Adalimumab also provided information at a molecular level for further understanding the clinical advantages of Adalimumab therapy compared with Infliximab.TNF is an immunity-modulating cytokine required for immune processes. The unregulated activities of TNFs can lead to the development of inflammatory diseases. Excess amounts of TNF␣ expressed in cells are associated with the development of immune diseases, including rheumatoid arthritis, Crohn's disease, psoriatic arthritis, and inflammatory bowel disease (1, 2). The function of TNF␣ requires smooth interaction with its two receptors, TNF receptor 1 (TNFR1) 4 and TNF receptor 2 (TNFR2). Blocking the interaction between TNF␣ and TNFRs has successfully been developed as a therapy in treating inflammatory or autoimmune diseases (3,4). TNF␣ neutralization therapies, including the use of a soluble TNFR2-Fc recombinant (Etanercept), a mouse-human chimera mAb (Infliximab), or a human mAb (Adalimumab), have been introduced in the past decades for the management of rheumatoid arthritis and other immune diseases (5).Although all of these TNF␣ blockers function by interrupting the TNF␣-TNFR interaction, information on whether the different TNF␣ inhibitors have similar clinical efficacy remains controversial because of the lack of randomized clinical trial meta-analyses. In the early stages of clinical usage of Infliximab, its discontinuation was reported to result in loss of response. This largely affected patients who received long term treatment and later discontinued use (6). Approximately 10% of...

Real-life experience with switching TNF-α inhibitors in ankylosing spondylitis

“…Most of these side effects were mild or moderate infusion reactions, which were sometimes overweighed and resulted in earlier switches than it would have been necessary. But these side effects, and of course the secondary loss of efficacy, can be explained by the unique chemical structure of this drug (25). The chimeric monoclonal antobody induces production of anti-drug antibodies more intensively than the humanised ones (adalimumab and golimumab) and the receptor fusion protein etanercept.…”

EFab domain substitution as a solution to the light-chain pairing problem of bispecific antibodies

“…Finally, we report the crystal structure of the antibody adalimumab Fab with the EFab domain substitution. In comparison with the previously reported adalimumab Fab and IgE Fc structures, 18,19 the adalimumab EFab shows a high degree of similarity in the variable domains. However, clear differences in the relative domain orientation of variable domains with respect to constant domains are observed that do not appear to have a detrimental effect on target antigen binding.…”

“…The VH and VL domains exhibit typical geometry and the overall variable domain structure within the framework regions and complementarity-determining regions is very similar between the adalimumab EFab and adalimumab Fab (PDB id: 4NYL, 3WD5) (Figure 5A). 19 A superposition of the VH and VL domains of EFab and Fab show a root mean square deviation (rmsd) of 0.37 Å (Cα atoms only) (Figure 5B), demonstrating the high structural similarity. In contrast, when the Cϵ2 domains of the EFab are superimposed to the Cϵ2 domains of the IgE Fc (PDB id: 2WQR) 16 the rmsd of the Cα atoms is 1.32 Å, indicating less structural similarity (Figure 5B).…”

“…The monovalent binding kinetics of adalimumab EFab to human tumor necrosis factor (TNF) were determined using surface plasmon resonance (SPR) and compared to the WT Fab (Figure 7), which has been previously reported. 19 The substitution of the EFab domain slowed the association rate slightly from 3.9 x 10 6  M −1 s −1 to 2.5 x 10 6  M −1 s −1 while it increased the off rate from 5.8 x 10 6  M −1 s −1 to 8.0 x 10 6  M −1 s −1 (Table S1). The impact on affinity was two-fold lower (from 0.15 nM to 0.32 nM).

10.1080/19420862.2018.1519631-F0007Figure 7.SPR sensograms performed on a Biacore T200 at 25°C in HBS-EBP buffer with a CM5 chip, with hTNFalpha-Fc capture by immobilized anti-hFc antibody.

…”

Expression, purification, crystallization and preliminary X-ray analysis of the HER3–9E12 Fab complex

“…Moreover, comparing the epitopes of different antibodies to the same antigen has garnered significant interest in the field of antibody engineering and targeted therapy. For example, the comparison of the different epitopes of adalimumab and infliximab in complex with TNF using crystallography provided direct evidence of the adalimumab epitope as well as information on a molecular level to further understand the clinical advantages of adalimumab versus infliximab therapy (Hu et al, 2013). Thus, we launched a crystallographic study to investigate the precise epitope of HER3 recognized by 9E12.…”