Full therapeutic IgG1 antibody complex with FcγIIa/b and FcγIIIa receptors examined using all-atom molecular dynamics simulations

ABSTRACT Monoclonal antibodies are emerging as the predominant type of biological drug. Their inherent advantages such as target specificity, long serum half-life and lower toxicity profile ensure that pharmaceutical companies will continue develop this technology ([1]). We have performed molecular dynamics simulations of full therapeutic antibody- Fcγ receptor complexes to obtain insights into their interactions with various FcγRs to discover possible future improvements of mAbs. Affinity of bound monoclonal antibodies was assessed using two different free energy calculation methods the MM/GBSA and the Bennet acceptance ration (BAR)[2,3]. Obtained results for MM/GBSA binding affinity between different FcγRs were in agreement with the reference experiment. G236A mutation was assessed but we could not establish an increase in affinity. BAR results show increased affinity across all FcγRs for the mutated mAb, but this result is not in line with the data in reference article. Novel interactions between the Fab region of the antibody and the FcγRs were discovered which may hold possible leads for future improvement of antibodies.