Fab-dimerized glycan-reactive antibodies are a structural category of natural antibodies.
Natural antibodies (Abs) can target host glycans on the surface of pathogens. We studied the evolution of glycan-reactive B cells of rhesus macaques and humans using glycosylated HIV-1 envelope (Env) as a model antigen. 2G12 is a broadly neutralizing Ab (bnAb) that targets a conserved glycan patch on Env of geographically diverse HIV-1 strains using a unique heavy-chain (VH) domain-swapped architecture that results in fragment antigen-binding (Fab) dimerization. Here, we describe HIV-1 Env Fab-dimerized glycan (FDG)-reactive bnAbs without VH-swapped domains from simian-human immunodeficiency virus (SHIV)-infected macaques. FDG Abs also recognized cell-surface glycans on diverse pathogens, including yeast and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike. FDG precursors were expanded by glycan-bearing immunogens in macaques and were abundant in HIV-1-naive humans. Moreover, FDG precursors were predominately mutated IgM+IgD+CD27+, thus suggesting that they originated from a pool of antigen-experienced IgM+ or marginal zone B cells.
Williams, Wilton B., R Ryan Meyerhoff, R. J. Edwards, Hui Li, Kartik Manne, Nathan I. Nicely, Rory Henderson, et al. “Fab-dimerized glycan-reactive antibodies are a structural category of natural antibodies.” Cell 184, no. 11 (May 27, 2021): 2955-2972.e25. https://doi.org/10.1016/j.cell.2021.04.042.