In Vitro Evolution of an Influenza Broadly Neutralizing Antibody is Modulated by Hemagglutinin Receptor Specificity

Wu NC, et al., 8:15371, Nat Commun, 2017

The discovery of human broadly neutralizing antibodies (bnAbs) against influenza virus has provided significant contributions toward the development of a universal influenza vaccine. C05, is a bnAb that targets the influenza haemagglutinin (HA) receptor-binding site (RBS). Reported in here is an investigation of the evolution of bnAb C05 by analyzing its functional sequence space. Binding affinities of C05 variants against hemagglutinins from different influenza strains were studied by using Bio-Layer Interferometry (BLI). All BLI assays were performed using a Pall ForteBio Octet RED system. Biotinylated HA0 was immobilized onto Streptavidin biosensor probes and dipped in samples (supernatants from transfected cells or purified Fab). KD value was determined using a 1:1 binding model. When the binding affinities were relatively weak or the non-specific binding (NSB) was observed, a 2:1 heterogeneous ligand model was used to obtain a better fitting. Overall data of this study suggest that the highly conservative substitutions in HA RBS among different influenza strains may modulate the evolution of bnAbs differently.

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