Selected Grantee Publications
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- niaid
- Vaccines/Therapeutics
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Structural Mapping of Polyclonal IgG Responses to HA After Influenza Virus Vaccination or Infection
León et al., mBio. 2025.
https://pubmed.ncbi.nlm.nih.gov/39912630
Seasonal influenza viruses cause hundreds of thousands of deaths each year and up to a billion infections; under the proper circumstances, influenza A viruses with pandemic potential could threaten the lives of millions more. Many promising universal flu vaccine candidates currently focus on guiding immune responses to highly conserved epitopes on the central stem of the influenza hemagglutinin (HA) viral fusion protein. To support the further development of these stem-targeting vaccine candidates, researchers used negative stain electron microscopy to assess the prevalence of central stem-targeting antibodies in individuals (male and female) who were exposed to influenza antigens through traditional vaccination or natural infection during the 2018–2019 flu season. Results demonstrated humoral IgGs targeting highly conserved regions on both H1 and H3 subtype HAs found in both vaccinated and infected patients. Results from this study support the need for further characterization of protective responses toward conserved epitopes and provide a baseline for examining antibody responses. Supported by ORIP (K01OD036063) and NIAID.
Structures of Respiratory Syncytial Virus G Bound to Broadly Reactive Antibodies Provide Insights into Vaccine Design
Juarez et al., Scientific Reports. 2025.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11906780
Respiratory syncytial virus (RSV) is one of the leading causes of severe lower respiratory infection in both infants and older adults. RSV viral entry and modulation of the host immunity is mediated by attachment glycoprotein RSV G binding to the chemokine receptor CX3CR1. Antibodies isolated from RSV-exposed individuals have shown great promise in host protection. Researchers using an ORIP-funded electron microscope, in conjunction with X-ray crystallography, have solved the structure of these antibodies bound to the RSV G protein and identified a novel dual antibody binding region. The presence of dual antibody binding sites indicates the potential to elicit antibody responses that resist virus escape. These findings will help develop next-generation RSV prophylactics and provide insight for new concepts in vaccine design. Supported by ORIP (S10OD027012, S10OD025097), NIAID, NHGRI, and NIGMS.
Suppression of Viral Rebound by a Rev-Dependent Lentiviral Particle in SIV-Infected Rhesus Macaques
Hetrick et al., Gene Therapy. 2025.
https://pubmed.ncbi.nlm.nih.gov/39025983/
Viral reservoirs are a current major barrier that prevents an effective cure for patients with HIV. Antiretroviral therapy (ART) effectively suppresses viral replication, but ART cessation leads to viral rebound due to the presence of viral reservoirs. Researchers conducted in vivo testing of simian immunodeficiency virus (SIV) Rev-dependent vectors in SIVmac239-infected male and female Indian rhesus macaques, 3–6 years of age, to target viral reservoirs. Treatment with the SIV Rev-dependent vector reduced viral rebound and produced neutralizing antibodies following ART cessation. These results indicate the potential to self-control plasma viremia through a neutralizing antibody-based mechanism elicited by administration of Rev-dependent vectors. This research could guide future studies focused on investigating multiple vector injections and quantifying cell-mediated immune responses. Supported by ORIP (P51OD011104, P40OD028116), NIAID, and NIMH.
Indoleamine-2,3-Dioxygenase Inhibition Improves Immunity and Is Safe for Concurrent Use with cART During Mtb/SIV Coinfection
Singh et al., JCI Insight. 2024.
https://pubmed.ncbi.nlm.nih.gov/39114981/
HIV and tuberculosis (TB) coinfection can lead to TB reactivation that is caused by chronic immune system activation. Researchers explored indoleamine-2,3-dioxygenase (IDO) inhibition as a host-directed therapy (HDT) to mitigate immune suppression and TB reactivation in a rhesus macaque Mycobacterium tuberculosis (Mtb)/simian immunodeficiency virus (SIV) model. The IDO inhibitor D-1-methyl tryptophan improved T-cell immunity, reduced tissue damage, and controlled TB-related inflammation without interfering with the efficacy of combinatorial antiretroviral therapy (cART). These findings support IDO inhibition as a potential HDT in HIV/TB coinfection, providing a strategy to balance immune control while preventing TB reactivation in cART-treated patients. Supported by ORIP (S10OD028732, U42OD010442, S10OD028653) and NIAID.
Potent Broadly Neutralizing Antibodies Mediate Efficient Antibody-Dependent Phagocytosis of HIV-Infected Cells
Snow et al., PLOS Pathogens. 2024.
https://pubmed.ncbi.nlm.nih.gov/39466835
This study investigates the role of potent broadly neutralizing antibodies (bNAbs) in mediating antibody-dependent cellular phagocytosis (ADCP) of HIV-infected cells. Researchers developed a novel cell-based approach to assess the ADCP of HIV-infected cells expressing natural conformations of the viral envelope glycoprotein, which allows the virus to infect a host cell. The findings in this study demonstrate that bNAbs facilitate efficient ADCP, highlighting their potential in controlling HIV infection by promoting immune clearance of infected cells. This study provides valuable insights into antibody-mediated immune mechanisms and supports the development of antibody-based therapies and vaccines targeting HIV. Supported by ORIP (P51OD011106) and NIAID.
Administration of Anti-HIV-1 Broadly Neutralizing Monoclonal Antibodies With Increased Affinity to Fcγ Receptors During Acute SHIV AD8-EO Infection
Dias et al., Nature Communications. 2024.
https://www.nature.com/articles/s41467-024-51848-y
Anti-HIV broadly neutralizing antibodies (bNAbs) mediate virus neutralization and antiviral effector functions through Fab and Fc domains, respectively. This study investigated the efficacy of wild-type (WT) bNAbs and modified bNAbs with enhanced affinity for Fcγ receptors (S239D/I332E/A330L [DEL]) after acute simian-HIVAD8-EO (SHIVAD8-EO) infection in male and female rhesus macaques. The emergence of the virus in the plasma and lymph nodes occurred earlier in macaques given DEL bNAbs than in those given WT bNAbs. Overall, the administration of DEL bNAbs revealed higher levels of immune responses. The results suggest that bNAbs with an enhanced Fcγ receptor affinity offer a potential therapeutic strategy by targeting HIV more effectively during early infection stages. Supported by ORIP (P40OD028116), NCI, and NIAID.
Comparison of the Immunogenicity of mRNA-Encoded and Protein HIV-1 Env-ferritin Nanoparticle Designs
Mu et al., Journal of Virology. 2024.
https://journals.asm.org/doi/10.1128/jvi.00137-24
Inducing broadly neutralizing antibodies (bNAbs) against HIV-1 remains a challenge because of immune system limitations. This study compared the immunogenicity of mRNA-encoded membrane-bound envelope (Env) gp160 to HIV-1 Env-ferritin nanoparticle (NP) technology in inducing anti-HIV-1 bNAbs. Membrane-bound mRNA encoding gp160 was more immunogenic than the Env-ferritin NP design in DH270 UCA KI mice, but at lower doses. These results suggest further analysis of mRNA design expression and low-dose immunogenicity studies are necessary for anti-HIV-1 bNAbs. Supported by ORIP (P40OD012217, U42OD021458) and NIAID.
Anti–PD-1 Chimeric Antigen Receptor T Cells Efficiently Target SIV-Infected CD4+ T Cells in Germinal Centers
Eichholtz et al., The Journal of Clinical Investigation. 2024.
https://pubmed.ncbi.nlm.nih.gov/38557496/
Researchers conducted adoptive transfer of anti–programmed cell death protein 1 (PD-1) chimeric antigen receptor (CAR) T cells in simian immunodeficiency virus (SIV)–infected rhesus macaques of both sexes on antiretroviral therapy (ART). In some macaques, anti–PD-1 CAR T cells expanded and persisted concomitant with the depletion of PD-1+ memory T cells—including lymph node CD4+ follicular helper T cells—associated with depletion of SIV RNA from the germinal center. Following CAR T infusion and ART interruption, SIV replication increased in extrafollicular portions of lymph nodes, plasma viremia was higher, and disease progression accelerated, indicating that anti–PD-1 CAR T cells depleted PD-1+ T cells and eradicated SIV from this immunological sanctuary. Supported by ORIP (U42OD011123, U42OD010426, P51OD010425, P51OD011092), NCI, NIAID, and NIDDK.
Vaccination Induces Broadly Neutralizing Antibody Precursors to HIV gp41
Schiffner et al., Nature Immunology. 2024.
https://pubmed.ncbi.nlm.nih.gov/38816615
Primary immunogens that induce rare broadly neutralizing antibody (bnAb) precursor B cells are needed to develop vaccines against viruses of high antigenic diversity. 10E8-class bnAbs must possess a long, heavy chain complementarity determining region 3 (HCDR3) with a specific binding motif. Researchers developed germline-targeting epitope scaffolds with an affinity for 10E8-class precursors that exhibited epitope structural mimicry and bound bnAb-precursor human naive B cells in ex vivo screens. Protein nanoparticles induced bnAb-precursor responses in stringent mouse models and rhesus macaques, and mRNA-encoded nanoparticles triggered similar responses in mice. This study showed that germline-targeting epitope scaffold nanoparticles can elicit rare bnAb-precursor B cells with predefined binding specificities and HCDR3 features. Supported by ORIP (P51OD011132, U42OD011023), NIAID, and NIGMS.
Broad Receptor Tropism and Immunogenicity of a Clade 3 Sarbecovirus
Lee et al., Cell Host and Microbe. 2023.
https://www.sciencedirect.com/science/article/pii/S1931312823004225
Investigators showed that the S glycoprotein of the clade 3 sarbecovirus PRD-0038 in the African Rhinolophus bat has a broad angiotensin-converting enzyme 2 (ACE2) usage and that receptor-binding domain (RBD) mutations further expand receptor promiscuity and enable human ACE2 utilization. They generated a cryogenic electron microscopy structure of the RBD bound to ACE2, explaining receptor tropism and highlighting differences between SARS-CoV-1 and SARS-CoV-2. PRD‑0038 S vaccination elicits greater titers of antibodies cross-reacting with vaccine-mismatched clade 2 and clade 1a sarbecoviruses, compared with SARS-CoV-2. These findings underline a potential molecular pathway for zoonotic spillover of a clade 3 sarbecovirus, as well as the need to develop pan-sarbecovirus vaccines and countermeasures. Supported by ORIP (S10OD032290, S10OD026959, S10OD021644), NIAID, NCI, and NIGMS.