Thermodynamic analysis of the binding of 2F5 (fab and immunoglobulin G forms) to its gp41 epitope reveals a strong influence of the immunoglobulin Fc region on affinity

Abstract

Background: Little is known regarding the thermodynamics of binding of the broadly neutralizing anti-HIV-1 mAb 2F5 to its gp41 epitope. Results: Isothermal titration calorimetry reveals strong differences between IgG and Fab. Conclusion: Residues flanking the core epitope and the immunoglobulin Fc region contribute strongly to affinity by allosteric mechanisms. Significance: The results may help to develop new therapeutics and/or vaccines against HIV and to understanding Ag-Ab recognition. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.