Fig. 4: Isolation and characterization of heterologous HIV-1 neutralizing mAbs in neonatal SHIV infection.

A Overview of BEAM-Ab (10X Genomics) pipeline and analytical plan used to isolate antigen-reactive B cells from representative RMs that generated plasma heterologous HIV-1 nAbs following neonatal SHIV infection. B Summary of BEAM-Ab assay outcomes from two representative RMs, V093 and V055, from which we isolated heterologous HIV-1 Env binding and nAbs; DH1518.1, DH1518.2 and DH1523. C Binding profile of DH1518.1, DH1518.2, and DH1523. MAb binding was measured via ELISA at OD450nm against heterologous and autologous SOSIP trimers used as B cell baits in BEAM-Ab. D (Left) NSEM structure of DH1518.1 (green) in complex with T250SOSIP trimer (gray). Candidate glycans within the mAb binding site are shown in different colors and labeled on the trimer. (Right) Overlay of DH1518.1 (green) and DH1518.2 (purple) in complex with the same T250 trimer. NSEM was performed with IgGs. E Neutralization curves of DH1518.1, DH1518.2, and DH1523 with maximal neutralization titers against sensitive heterologous tier 2 HIV-1 strains and MuLV. The percent viral quasi-species neutralized per virus at different mAb concentration is shown and the dash lines indicate 0 and 50% neutralization points; the latter may be used to determine IC50 titer that achieves optimal neutralization. F Summary of neutralization titer and breadth of DH1518.1 and DH1518.2 against a panel of 119 heterologous tier 2 HIV-1 strains as well as the reference HIV-1 neutralization global panel of 9 heterologous strains; both panels were tested in separate laboratories. G Neutralization epitope mapping for DH1518.1 and DH1518.2 against HIV-1 25710, a representative sensitive heterologous tier 2 HIV-1 strain shown in panel (E). MAbs were tested for neutralization of HIV-1 bearing wild-type or mutant Env. Mutations were created to disrupt V2-apex (N160K), V3-glycan (N332A) and CD4BS (N280D) bnAb epitopes. Neutralization assays were performed in TZM-bl cells and titers reported as IC50 in µg/ml as shown in the neutralization key. B, C, E, G Source data are provided as a Source Data file.