Selected Grantee Publications
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.
Whole-Genome Sequences of Six Borrelia recurrentis Strains Obtained via PacBio Sequencing
Gaber et al., Microbiology Resource Announcements. 2025.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11895452
The spirochetal bacterium Borrelia recurrentis causes louse-borne relapsing fever (LBRF), which leads to significant morbidity and mortality in several African countries. Previous sequencing studies of B. recurrentis demonstrated discrepancies and did not accurately define the antigenic variation system. In this study, researchers used long-read PacBio technology to conduct whole-genome sequencing of six B. recurrentis strains that had been isolated from LBRF patients earlier. The resulting sequences of each genome included one linear chromosome and five linear plasmids, whose average size was 1,284,895 bp, with the mean GC content being 27.5%. Supported by ORIP (T32OD011083) 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.
Quorum Sensing LuxR Proteins VjbR and BabR Jointly Regulate Brucella abortus Survival During Infection
Caudill et al., Journal of Bacteriology. 2025.
https://pubmed.ncbi.nlm.nih.gov/40013834
Brucella abortus is a zoonotic bacterial pathogen that causes brucellosis, a persistent chronic infection that is globally endemic. B. abortus uses quorum sensing to escape immune clearance attempts, regulate virulence, and cause persistent infection within hosts. B. abortus quorum sensing system comprises two LuxR proteins, VjbR and BabR, as well as two signals, dodecanoyl (C12 AHL) and 3-oxododecanoyl (3-OXO-C12 AHL) homoserine lactone. Using chronic infection 6- to 7-week-old C57Bl/6 and BALB/c male and female mouse models, researchers found that the ΔvjbRΔbabR double-deletion strain was attenuated compared with single mutants. These results demonstrate that both quorum sensing proteins, VjbR and BabR, coordinate to maintain survival. This study helps further characterize the Brucella quorum sensing systems and indicates that further attention should be given to the joint interactions between VjbR and BabR in controlling virulence. Supported by ORIP (T32OD028239) and NIAID.
Liver-Specific Transgenic Expression of Human NTCP In Rhesus Macaques Confers HBV Susceptibility on Primary Hepatocytes
Rust et al., PNAS. 2025.
https://pubmed.ncbi.nlm.nih.gov/39937851
This study establishes the first transgenic nonhuman primate model for hepatitis B virus (HBV). Male and female rhesus macaques were engineered to express the human HBV receptor, NTCP (hNTCP), specifically in the liver. Researchers used PiggyBac transposon technology to introduce a liver-specific NTCP transgene into embryos, which were then implanted into surrogate females. The resulting offspring expressed hNTCP in hepatocytes and demonstrated high susceptibility to HBV infection. This model overcomes the species-specific limitations of HBV research, providing a powerful tool for studying HBV biology and evaluating HBV treatments in a clinically relevant model system. Supported by ORIP (P51OD011092), NIDA, and NIAID.
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.
Recombinant Simian Varicella Virus–Simian Immunodeficiency Virus Vaccine Induces T and B Cell Functions and Provides Partial Protection Against Repeated Mucosal SIV Challenges in Rhesus Macaques
Pahar et al., Viruses. 2022.
https://www.doi.org/10.3390/v14122819
An effective vaccine is needed urgently to control the global HIV epidemic completely by 2030. Recombinant simian varicella virus (rSVV) vaccines expressing SIV antigens offer a potential new approach in the evaluation of HIV vaccine candidates. Building on their previous findings, the investigators induced systemic and mucosal immune responses with live, attenuated rSVV vaccinations followed by SIV group–specific antigen and SIV envelope protein boosts in female rhesus macaques treated with repeated intravaginal SIV challenges. Their findings demonstrate that the vaccination with protein boosts induces a 37.5% efficacy rate against pathogenic SIV challenge by generating mucosal memory, virus‑specific neutralizing antibodies, binding antibodies, and polyfunctional T cell responses. Supported by ORIP (P51OD011104) and NIAID.
Gut Microbiome Dysbiosis in Antibiotic-Treated COVID-19 Patients Is Associated with Microbial Translocation and Bacteremia
Bernard-Raichon et al., Nature Communications. 2022.
https://www.doi.org/10.1038/s41467-022-33395-6
The investigators demonstrated that SARS-CoV-2 infection induced gut microbiome dysbiosis in male mice. Samples collected from human COVID-19 patients of both sexes also revealed substantial gut microbiome dysbiosis. Analysis of blood culture results testing for secondary microbial bloodstream infections with paired microbiome data indicated that bacteria might translocate from the gut into the systemic circulation of COVID-19 patients. These results were consistent with a direct role for gut microbiome dysbiosis in enabling dangerous secondary infections during COVID-19. Supported by ORIP (S10OD021747), NCI, NHLBI, NIAID, and NIDDK.
Transient T Cell Expansion, Activation, and Proliferation in Therapeutically Vaccinated Simian Immunodeficiency Virus–Positive Macaques Treated with N-803
Harwood et al., Journal of Virology. 2022.
https://www.doi.org/10.1128/jvi.01424-22
Many HIV vaccine strategies induce neutralizing antibodies and CD8+ T cells, but more information on these protective immune responses is needed. Researchers hypothesized that CD8+ T cells elicited by vaccination during antiretroviral therapy (ART) would be recalled and boosted by treatment with N-803 after ART discontinuation. They tested this approach in male Mauritian cynomolgus macaques infected with simian immunodeficiency virus. The regimen enhanced the frequency of Gag-specific lymphocytes with phenotypes associated with activation, proliferation, and memory in the peripheral blood and lymph nodes of vaccinated animals. These results help demonstrate N-803’s potential as an immunomodulatory agent for treatment of HIV. Supported by ORIP (P51OD011106) and NIAID.
Long-Term Evolutionary Adaptation of SIVcpz toward HIV-1 Using a Humanized Mouse Model
Schmitt et al., Journal of Medical Primatology. 2022.
https://www.doi.org/10.1111/jmp.12616
Chimpanzee-derived simian immunodeficiency viruses (SIVcpz) are thought to have evolved into the highly pathogenic HIV-1 Group M, but the genetic adaptations required for SIV progenitor viruses to become pathogenic and established as HIVs in the human population have remained unclear. Using humanized mice of both sexes, researchers mimicked the evolution of SIVcpz into HIV-1 Group M through serial passaging. After four generations, the researchers observed increased initial viral load, increased CD4+ T cell decline, and nonsynonymous substitutions. Overall, these data indicate increased viral fitness and pathogenicity. This work also demonstrates the utility of humanized mice in recreating the adaptive pressures necessary for the evolution of SIVcpz into HIV-1. Supported by ORIP (P51OD011104, P51OD011106), NCATS, and NIAID.