Structural Insights into the Neutralization Properties of the Fully Human, Anti-interferon Monoclonal Antibody Sifalimumab.

ABSTRACT: We report the three-dimensional structure of human interferon ?-2A (IFN-?2A) bound to the Fab fragment of a therapeutic monoclonal antibody (sifalimumab; IgG1/?). The structure of the corresponding complex was solved at a resolution of 3.0 Å using molecular replacement and constitutes the first reported structure of a human type I IFN bound to a therapeutic antibody. This study revealed the major contribution made by the first complementarity-determining region in each of sifalimumab light and heavy chains. These data also provided the molecular basis for sifalimumab mechanism of action. We propose that its interferon-neutralizing properties are the result of direct competition for IFN-?2A binding to the IFN receptor subunit 1 (IFNAR1) and do not involve inhibiting IFN-?2A binding to the IFN receptor subunit 2 (IFNAR2).

SUBMITTER: Oganesyan V 

PROVIDER: S-EPMC4463443 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature