Expansion of VRC01-class B cells in vivo. (A) Representative flow cytometric plots of iv8-binding naive B cells from one wild-type mouse and one 3BNC60^SI mouse of 10 analyzed (left panels). Arithmetic mean frequency of iv8-binding naive B cells from 10 mice per group. Error bars indicate SEM (right). One representative experiment of three is shown. (B) Representative flow cytometry plots showing proliferation of adoptively transferred 3BNC60^SI cells as indicated by CTV dilution at 5 d after injection of (from left to right) control mAb (ib5, binds glb12 but not gl3BNC60) with Ribi, mAb iv8 with Ribi, iv8 Fab nanoparticles (np) without Ribi, iv8 Fab nanoparticles with Ribi, and CTV-labeled control PGT121 knock-in B cells in response to iv8 Fab nanoparticles with Ribi. One representative animal of four per group is shown from one experiment of three. (C) Flow cytometry plots pregated on total B cells (lymphocytes, singlets, dump⁻, live, B220⁺) indicating frequency of 3BNC60^SI knock-in cells of total B cells at 14 d after injection of the indicated constructs in Ribi adjuvant conjugated to 2W1S peptide or not. One representative animal of two to five per group in one experiment of three. (D) Frequency of 3BNC60^SI knock-in cells in mice injected as in C. Lines indicate arithmetic mean values of individual mice per group, with error bars indicating SEM of two replicate experiments with two to five mice per group per experiment. Statistics were calculated using the Mann–Whitney U test. *, P ≤ 0.05; **, P ≤ 0.01.