Human Monoclonal Antibodies That Neutralize Pandemic GII.4 Noroviruses Gabriela Alvarado, Khalil Ettayebi, Robert L. Atmar, Robin G. Bombardi, Nurgun Kose, Mary K. Estes, James E. Crowe  Gastroenterology  Volume 155, Issue 6, Pages 1898-1907 (December 2018) DOI: 10.1053/j.gastro.2018.08.039 Copyright © 2018 AGA Institute Terms and Conditions

Figure 1 Neutralization of GII.4 Sydney 2012 using VLPs or live virus. (A) EC50 values for all isolated IgGs and IgAs using a VLP blockade assay and the antibody concentration at which hemagglutination was inhibited when using VLPs and O Rh+ red blood cells. The > symbols indicate blockade EC50 values >100 μg/mL for IgGs or >113 μg/mL for IgAs or HAI titers > 15 μg/mL. (B) The absorbance values when plates were read at optical density (O.D.) 405 nm for selected IgGs and IgAs when antibodies were diluted serially, combined with GII.4 Sydney 2012 VLPs and added to porcine gastric mucin (PGM). (C) Inhibition of replication of GII.4 Sydney 2012 virus using selected IgGs, IgAs, and a nonspecific human monoclonal antibody (mAb) were tested in a human intestinal enteroid system. An additional control for each experiment was virus incubated without an mAb. The IC50 value for each mAb is indicated in each individual graph. The data presented are an average of 2 independent experiments for NORO-263, -250B, -320, -273A, and -318 and a Dengue virus–specific control antibody 2D22. The number of genome equivalents for each concentration tested for each mAb, including the no-antibody control, was the average of 6 replicates tested. Ab, antibody. Gastroenterology 2018 155, 1898-1907DOI: (10.1053/j.gastro.2018.08.039) Copyright © 2018 AGA Institute Terms and Conditions

Figure 2 Competition binding of GII.4-specific mAbs on GII.4 Sydney 2012 P domain with the Octet® Red96 system. Epitope binning was performed using biolayer interferometry. GST-tagged GII.4 Sydney 2012 P domain was loaded onto anti-GST tips; then the first antibody was loaded, followed by loading of the second antibody. The numerical data indicate percent binding of the second antibody in the presence of the first antibody. Yellow, green, and magenta boxes indicate potential binding groups. Gastroenterology 2018 155, 1898-1907DOI: (10.1053/j.gastro.2018.08.039) Copyright © 2018 AGA Institute Terms and Conditions