# Eliciting neutralizing antibodies and B cell responses using novel HIV Env immunogens in non-human primates

> **NIH NIH P01** · SCRIPPS RESEARCH INSTITUTE, THE · 2024 · $3,442,683

## Abstract

Neutralizing antibodies are likely to be required for an effective HIV-1 vaccine. However, few candidate vaccines
efficiently elicit broadly neutralizing antibodies (bNAbs) following vaccination. Recently, the VRC working group
has elicited fusion peptide-directed bNAbs in guinea pigs and non-human primates (NHPs). Similarly, we recently
elicited bNAbs in rabbits following heterologous NFL (uncleaved) trimer-liposome prime:boosting at Scripps
where we activated B cell responses with targeted N-glycan deletions in the priming immunizations
(Dubrovskaya et al, Immunity 2019). We isolated two rabbit bNAbs that recapitulate the serum activity. These
bNAbs are directed against two distinct sites of Env vulnerability. The elicitation of neutralizing responses was
enhanced by targeted N-glycan deletion, high-density liposomal array and heterologous trimer restorative
boosting Env. In independent experiments in guinea pigs, we have elicited bNAbs in multiple animals also using
a N-glycan deletion, heterologous Env NFL prime:boost approach. These recent outcomes are encouraging
inroads toward the successful solution of a 3-decade-long problem. The new era of near-native trimeric spike
mimics, coupled with particulate array, structure-informed design and high-resolution analysis of Env-specific B
cell and lymph node responses, afford new opportunities to more efficiently elicit bNAbs. We propose an
integrated, multi-faceted approach blending the expertise of world leaders in HIV Env trimer design, analysis of
B cell responses and Abs following vaccination, NHP immune tissue analysis and EM-based analysis of ongoing
immune responses and high-resolution Ab:trimer interactions. We will use well-ordered trimer prime:boosting
that elicited bNAbs in rabbits and guinea pigs to elicit such responses in NHPs, translating success in small
animals to NHPs using novel immunogen design and presentation in Project 1 (Wyatt) and immunization of NFL
trimers into NHPs via Core B (Silvestri). We will use “real-time” serum Fab-to-trimer binding evaluated by EM
polyclonal IgG epitope mapping (EMPEM) in Core C (Ward) in complement with rapid mAb NGS-based mAb
cloning, sequencing and functional expression in Project 2 (Karlsson Hedestam). In collaboration with the VRC
(Mascola) we will define either non-neutralizing mAbs to mask unwanted non-neutralizing epitopes or to better
display the epitopes of cross-neutralizing mAbs. We will compare NFL trimer-liposomes to cell surface NFL trimer
array expressed from the exciting mRNA lipid encapsulation technology. We will assess if immunization in the
juvenile NHP B cell repertoire compared to adult macaques will better generate bNAbs as is observed during
human infection. To follow our discovery of a tier 2 CD4bs-directed bNAb following trimer-liposome vaccination,
termed E70, we will target the CD4bs by directed NFL trimer deglycosylation in the NHPs. Based on our recent
discovery of the very broadly neutralizing vaccine-induced mAb,...

## Key facts

- **NIH application ID:** 10800812
- **Project number:** 5P01AI157299-04
- **Recipient organization:** SCRIPPS RESEARCH INSTITUTE, THE
- **Principal Investigator:** Richard Thomas Wyatt
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $3,442,683
- **Award type:** 5
- **Project period:** 2021-02-04 → 2026-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10800812

## Citation

> US National Institutes of Health, RePORTER application 10800812, Eliciting neutralizing antibodies and B cell responses using novel HIV Env immunogens in non-human primates (5P01AI157299-04). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10800812. Licensed CC0.

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