Fig. 2: WIN332 elicits serum antibodies that target the V3-glycan epitope and neutralize serially more glycosylated viruses including low activity against the fully glycosylated autologous virus.
a,b, EMPEM results showing the binding of Fabs (colored) purified from the serum of WIN332-primed NHP 1 and 3 to WIN332 (gray; a) and NHP 1, 2 and 3 to RC1 (gray; b). c, Close-up views highlighting the interactions of the Fabs from NHP 1 and 3 (blue and red) with the Asn160 glycan of WIN332. WIN332 Env density is shown in gray with the model of RC1 (Protein Data Bank (PDB) 6ORO) with Asn332 glycan removed fit in (RC1 trimer ΔAsn332 glycan). d, Densities of NHP 1 Fab (green) bound to RC1 (gray) with RC1 model fit in (PDB 6ORO). Close-up views highlighting accommodation of Asn332 and Asn301 glycans on RC1. e–g, Comparison of Fab densities from NHP 1 (green), NHP 2 (dark blue) and NHP 3 (purple) with EPTC112 (pink), BG18 (orange) and PGT121 (cyan) Fab densities. h, Representative results of TZM-bl neutralization assays using purified immunoglobulins from the serum of WIN332-primed NHPs (n = 4) against pseudoviruses carrying gradually more native-looking Env proteins. 5MUT and BG505 (BG505 Thr332Asn) are fully glycosylated pseudoviruses. BG505 Asn301Ala is a modified version of the BG505 pseudovirus with a mutation that knocks out the V3-glycan epitope by removing the Asn301 glycan. Pie charts represent the V3-glycan epitope, and colored slices indicate present glycans.
