Glycan-masked engineered outer domains of HIV-1 gp120 and their use
Inventors
Chen, Xuejun • Boyington, Jeffrey • Holdsworth, Hongying Duan • Cheng, Cheng • Mascola, John R.
Assignees
US Department of Health and Human Services
Publication Number
US-11235056-B2
Publication Date
2022-02-01
Expiration Date
2038-03-26
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Abstract
Embodiments of immunogens based on the outer domain of HIV-1 gp120 and methods of their use and production are disclosed. Nucleic acid molecules encoding the immunogens are also provided. In several embodiments, the immunogens can be used to prime an immune response to gp120 in a subject, for example, to treat or prevent an HIV-1 infection in the subject.
Core Innovation
Embodiments of immunogens based on the engineered outer domain of human immunodeficiency virus type 1 (HIV-1) gp120 (eOD) are disclosed, which have been modified to include selective N-linked glycosylation sites (glycan-masking) to reduce off-target immune activation and improve immune focusing. These immunogens specifically bind to VRC01-class broadly neutralizing antibodies (bnAbs) and their inferred germline precursors, thereby activating a neutralizing antibody response targeting the conserved CD4-binding site (CD4bs) of gp120.
The major problem the invention addresses is the difficulty in eliciting protective immune responses to HIV-1, particularly to epitopes recognized by VRC01-class bnAbs. HIV-1 Env gp120 is heavily glycosylated and has evolved mechanisms to evade immune recognition. Available germline-targeting immunogens, such as the eOD-GT8 60 mer, while capable of activating VRC01-class precursors, also elicit a substantial off-target immune response, producing antibodies to non-CD4bs epitopes. This off-target response undermines the effectiveness of immunizations by diluting or distracting from the desired VRC01-class antibody activation.
To solve this, the disclosed immunogens introduce specific glycan sequons at strategic non-CD4bs positions on eOD-GT8 to mask off-target epitopes without compromising binding to VRC01-class antibodies or their precursors. This glycan-masking approach reduces antigenicity for non-CD4bs antibodies and enhances immunogenicity focusing, leading to a higher proportion of CD4bs-specific antibody responses and an increased elicitation of VRC01-class precursor antibodies in vivo. The eOD can be presented as a multimer on self-assembling protein nanoparticles (such as lumazine synthase 60 mer) or linked to carrier proteins or membranes to improve immunogenicity and utility.
Claims Coverage
The claims include three independent claims covering an isolated immunogen comprising an engineered gp120 outer domain and methods of inducing an immune response using the immunogen or compositions including it. Three main inventive features are extracted.
Engineered gp120 outer domain with specific amino acid sequences
The immunogen comprises an engineered gp120 outer domain comprising an amino acid sequence according to SEQ ID NO: 79 (Mut49), SEQ ID NO: 80 (Mut50), or SEQ ID NO: 16 (Mut16), which are glycan-masked variants derived from eOD-GT8 to reduce off-target immune activation.
Immune focusing by selective glycan-masking preserving CD4bs binding
The engineered gp120 outer domain specifically binds to VRC01-class broadly neutralizing antibodies and their inferred germline revertants, inducing an immune response that targets the VRC01 binding site of gp120, including activation of memory B cells where at least 50% bind to the VRC01 binding site.
Immunogen presentation using self-assembling protein nanoparticles and carriers
The engineered gp120 outer domain is linked directly or by a peptide linker to a self-assembling protein nanoparticle subunit, such as a lumazine synthase subunit (including specific SEQ ID NOs or close variants), or to a carrier protein, optionally by a glycine-serine peptide linker of no more than 30 amino acids (e.g., SEQ ID NO: 50) to form multimeric nanoparticles or conjugate immunogens.
The claims cover isolated immunogens of specific glycan-masked gp120 outer domains capable of focusing immune responses toward the CD4 binding site, their multimerization on protein nanoparticles including lumazine synthase 60 mers, linkage to carriers, and their use in compositions and methods of inducing protective immune responses against HIV-1.
Stated Advantages
The immunogens provide a substantially more focused immune response to the CD4-binding site of gp120 compared to prior eOD immunogens.
Glycan-masking reduces off-target non-CD4bs antibody responses, increasing the proportion and titer of CD4bs-specific antibodies and memory B cells.
Improved elicitation of VRC01-class precursor antibodies, which are capable of maturing into broadly neutralizing antibodies against diverse HIV-1 strains.
The immunogens maintain high affinity binding to VRC01-class antibodies and their inferred germline precursors, enabling more effective priming of a neutralizing immune response.
Documented Applications
Immunogens can be used to prime an immune response to the CD4 binding site of gp120 in a subject to treat or prevent HIV-1 infection.
Used as vaccines or immunogenic compositions administered alone or in prime-boost vaccination protocols, including boosting with HIV-1 Env ectodomain proteins.
Use in methods of generating immune responses that activate memory B cells targeting the VRC01 binding site and promote production of IGHV1-2*02 containing antibodies (germline precursors of VRC01-class bnAbs).
Generation of virus-like particles or protein nanoparticles displaying the engineered gp120 outer domain for immunization purposes.
Use in diagnostic or research applications as probes to detect and quantify CD4bs-directed antibodies.
Interested in licensing this patent?