# Project 2: Design and screening for immunogens to efficiently elicit anti-HIV-1 bNAbs

> **NIH NIH P01** · CALIFORNIA INSTITUTE OF TECHNOLOGY · 2020 · $845,350

## Abstract

Proj 2: Design and screening for immunogens to efficiently elicit anti-HIV-1 bNAbs PI: Pamela J. Bjorkman
An effective HIV vaccine likely requires induction of Abs against HIV-1 Env that neutralize across the majority
of circulating viral strains (broadly neutralizing antibodies; bNAbs). Because administered bNAbs are protective
against HIV-1 infection in animal models, it is widely believed that a vaccine that elicits bNAbs would prevent
infection. The fact that vaccine efforts have not yet succeeded preventing HIV-1 infection and/or eliciting
bNAbs may relate to the observation that inferred germline (iGL) forms of bNAbs only rarely bind to Env
proteins that are the targets of bNAbs. The germline targeting approach to vaccine design involves engineering
an iGL-binding Env protein that preferentially activates bNAb precursors and selects productive somatic
hypermutations (SHMs) during affinity maturation. Resulting memory B cells are then boosted by sequential
immunogens to shepherd bNAb production by selecting additional productive SHMs. Drs. Bjorkman and
Nussenzweig propose to apply this approach to target two classes of HIV-1 bNAb: a class related to PGT121
that binds to the base of the V3 variable loop and interacts with the N332gp120 glycan (V3/N332 bNAbs), and
IOMA-like bNAbs, a new class of CD4-mimetic CD4 binding site (CD4bs) bNAbs derived from the VH1-2
germline gene segment. The V3/N332 and IOMA classes were chosen because (i) V3/N332 Abs are among
the most potent of bNAbs, are commonly found in HIV-infected individuals who develop bNAbs, and
immunogen studies will be complementary to human clinical trials evaluating passive delivery of the V3/N332
bNAb 10-1074 to HIV-1–infected patients, (ii) IOMA's relatively low number of SHMs and its normal-length
CDRL3 suggest it may be more easily elicited than VRC01-class VH1-2–derived CD4bs bNAbs that are
heavily somatically mutated and contain rare 5-residue CDRL3s, and (iii) immunogen design will be facilitated
by the recent structure of a natively-glycosylated Env trimer bound to the V3/N332 bNAb 10-1074 and to
IOMA. With the goal of creating SOSIP-based Env trimers to target iGLs and shepherd maturation of V3/N332
and IOMA-like bNAbs, Dr. Bjorkman proposes a highly collaborative project with Dr. Nussenzweig to (1)
Solve structures of iGL–immunogen complexes to aid in structure-based immunogen design and library
screens to select immunogens, (2) Use structure-based design combined with library screening to identify
SOSIP trimers that bind V3/N332 iGLs with high affinity, (3) Use structural information to guide construction of
a yeast display library to find rare variants that bind IOMA iGL with high affinity, (4) Combine results from Aims
2 and 3 to create SOSIP-based immunogens that bind iGLs of both bNAbs and evaluate them in wildtype mice
and in mice produced by Dr. Nussenzweig to carry germline-reverted versions of IOMA and 10-1074. These
aims will be repeated using information from new ...

## Key facts

- **NIH application ID:** 9843100
- **Project number:** 5P01AI100148-07
- **Recipient organization:** CALIFORNIA INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** Pamela J Bjorkman
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $845,350
- **Award type:** 5
- **Project period:** — → —

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9843100

## Citation

> US National Institutes of Health, RePORTER application 9843100, Project 2: Design and screening for immunogens to efficiently elicit anti-HIV-1 bNAbs (5P01AI100148-07). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9843100. Licensed CC0.

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