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Igg3 Subclass Antibodies Recognize Antigenically Drifted Influenza Viruses And Sars-Cov-2 Variants Through Efficient Bivalent Binding, Marcus J. Bolton, Jefferson J.S. Santos, Claudia P. Arevalo, Trevor Griesman, Megan Watson, Shuk Hang Li, Paul Bates, Holly Ramage, Patrick C. Wilson, Scott E. Hensley

Department of Microbiology and Immunology Faculty Papers

The constant domains of antibodies are important for effector functions, but less is known about how they can affect binding and neutralization of viruses. Here, we evaluated a panel of human influenza virus monoclonal antibodies (mAbs) expressed as IgG1, IgG2, or IgG3. We found that many influenza virus-specific mAbs have altered binding and neutralization capacity depending on the IgG subclass encoded and that these differences result from unique bivalency capacities of the subclasses. Importantly, subclass differences in antibody binding and neutralization were greatest when the affinity for the target antigen was reduced through antigenic mismatch. We found that antibodies expressed …