In-silico Strategy for the Affinity Improvement of the Anti-TNF-α Antibody Drug by Site-Directed Mutagenesis Approach

Rheumatoid arthritis (RA) is an autoimmune disorder and one of the most common immunemediateddiseases [۱, ۲]. In patients with rheumatoid arthritis, significant damage is usually caused inthe joints of the hands and feet. Monoclonal antibody (mAb) is a type of targeted drug therapy for thetreatment of RA. These drugs specifically target tumor necrosis factor-alpha (TNF-α) and othercytokines that are closely related to RA. This approach reduces the side effects of traditional treatments[۳]. Adalimumab is an anti-TNF-α mAb and used for RA treatment [۴] .Complementary determiningregions (CDRs) from the Adalimumab are regions that bind to the TNF-α .The type of amino acids atthe site of TNF-α and CDR interaction is important. Site-directed mutagenesis is one of the methodswhich is used to improve the affinity of mAbs [۵, ۶]. In this study, the structure of TNF-α in complexwith Adalimumab was extracted from ۳dw۵ PDB code. SabDab server was applied to determine thesequences of CDRs. Moreover, SWISS-MODEL server was applied for modeling the three-dimensionalstructure of anti-TNF-α mAb, TNF-α and mutated anti-TNF-α mAbs .Pymol software was used todetermine the mAb-epitope binding site. Then, HADDOCK server was used to investigate theinteraction between mAbs and TNF-α .HADDOCK results showed that some of the mutations such asthe substitution of serine ۱۰۶ with arginine improved binding affinity. The effect of this mutation wasalso investigated with the mCSM-AB۲ web server and the binding affinity improvement was confirmed.Strategies for optimization of therapeutic mAbs can be applied to improve the function of mAbs.

کلیدواژه ها:

Site-directed mutagenesis ، Affinity ، Monoclonal antibody ، Rheumatoid arthritis ، Bioinformatics tools