Song, RuijiangOren, Deena A.Franco, DavidSeaman, MichaelHo, David D.2014-07-072013Song, Ruijiang, Deena A. Oren, David Franco, Michael S. Seaman, and David D. Ho. 2013. “Strategic addition of an N-linked glycan to a monoclonal antibody improves its HIV-1-neutralizing activity.” Nature biotechnology 31 (11): 10.1038/nbt.2677. doi:10.1038/nbt.2677. http://dx.doi.org/10.1038/nbt.2677.1087-0156http://nrs.harvard.edu/urn-3:HUL.InstRepos:12406952Ibalizumab is a humanized monoclonal antibody that binds human CD4—a key receptor for HIV—and blocks HIV-1 infection. However, HIV-1 strains with mutations resulting in loss of an N-linked glycan from the V5 loop of the envelope protein gp120 are resistant to ibalizumab. Previous structural analysis suggests that this glycan fills a void between the gp120 V5 loop and the ibalizumab L chain, perhaps causing steric hindrance that disrupts viral entry. If this void contributes to HIV-1 resistance to ibalizumab, we reasoned that ‘refilling’ it by engineering an N-linked glycan into the ibalizumab L chain at a position spatially proximal to gp120 V5 may restore susceptibility to ibalizumab. Indeed, one such ibalizumab variant neutralized 100% of 118 tested diverse HIV-1 strains in vitro, including ten strains resistant to parental ibalizumab. These findings demonstrate that the strategic placement of a glycan in the variable region of a monoclonal antibody can substantially enhance its activity.en-USJournal Article2014-07-0710.1038/nbt.2677