Fig 1: Immunization with Env NFL trimer-liposomes elicits apex-directed, cross-neutralizing serum antibodies in all NHPs.a, Surface representation of the HIV-1 Env trimer on the membrane (left) and trimer apex top view, adapted from its simian variant spike (EMDB: EMD-5273) (right). b, BLI binding analysis of Q23 and ZM233 NFL trimers to mature and inferred germ-line reverted RHA1 mAbs (IgL RHA1). c, Diagram of liposome conjugation to trimers (left). Right, negative-stain EM image of trimer-liposomes. Scale bar, 100 nm. The diagram was created using BioRender; Bale, S. https://BioRender.com/bww3j5e (2026). d, Calcium flux binding response of IgL CH01 B cells to Q23 trimer-liposomes or soluble trimer. e, Immunization regimen and NFL trimers used as immunogens. f, EMPEM analysis of NHPs Q7–Q12 after immunization with Q23 and ZM233 NFL trimers (the P2 bleed timepoint). g, The per-epitope (solid lines) and total (dashed line; sum of all per-epitope magnitudes) EMPEM magnitude by animal. The EMPEM magnitude is the average number of antibodies bound per trimer. The V2-apex magnitude is normalized by 3× to account for a 1:1 Fab:trimer binding stoichiometry. BLI and calcium flux experiments were repeated twice with similar results. The negative-stain EM image of trimer-liposomes was selected as a representative of several imaging sessions.Source data