Selected Grantee Publications
Innate Immune Regulation in HIV Latency Models
Olson et al., Retrovirology. 2022.
https://www.doi.org/10.1186/s12977-022-00599-z
Researchers are interested in developing therapeutic approaches to target latent HIV reservoirs, which are unaffected by antiretroviral therapy. Previous studies suggest that HIV latency might be related to viral RNA sensing, interferon (IFN) signaling, and IFN-stimulated gene (ISG) activation. In this study, the researchers evaluated responses to stimulation by retinoic acid–inducible gene I agonists and IFN in multiple CD4+ T cell line models for HIV latency. The models represented various aspects of latent infection and viral control. Several of the cell lines demonstrated reduced ISG induction, suggesting that long-term latency might be related to dysregulation of the downstream IFN response. These effects likely reflect transcriptional changes occurring within a core set of ISGs and altering IFN responses. Additional studies could provide insight into the functions of these ISGs in HIV latency. Supported by ORIP (P51OD010425), NCATS, and NIAID.
Substitutions in Nef That Uncouple Tetherin and SERINC5 Antagonism Impair Simian Immunodeficiency Virus Replication in Primary Rhesus Macaque Lymphocytes
Janaka et al., Journal of Virology. 2022.
https://www.doi.org/10.1128/jvi.00176-22
Tetherin inhibits the release of certain enveloped viruses from infected host cells. Most simian immunodeficiency viruses (SIVs) use Nef, a nonenzymatic accessory protein, to overcome this restriction. Nef also has been shown to enhance viral infectivity by preventing the incorporation of SERINC5 into virions. Researchers demonstrated previously that tetherin antagonism is necessary for efficient SIV replication in rhesus macaques. They explored this effect by defining substitutions within Nef that distinguish tetherin and SERINC5 antagonism. The researchers engineered an SIV molecular clone with substitutions that uncouple relevant Nef functions. This clone can be used to further study the effects of tetherin and adaptive immune responses. Supported by ORIP (P51OD011106) and NIAID.
A Cellular Trafficking Signal in the SIV Envelope Protein Cytoplasmic Domain Is Strongly Selected for in Pathogenic Infection
Lawrence et al., PLOS Pathogens. 2022.
https://www.doi.org/10.1371/journal.ppat.1010507
Envelope glycoproteins within the cytoplasmic domain of HIV and simian immunodeficiency virus (SIV) include a tyrosine-based motif that mediates endocytosis and polarized sorting in infected cells. Mutation of this tracking signal has been shown to lead to suppressed viral replication and failed systemic immune activation, but the mechanism has not been explored fully. Using rhesus and pigtail macaque models, the researchers demonstrated that molecular clones containing the mutations reconstitute signals for both endocytosis and polarized sorting. Their findings suggest strong selection pressure for these processes during pathogenic HIV and SIV infection. Supported by ORIP (P51OD011104), NCI, and NIAID.
Large Comparative Analyses of Primate Body Site Microbiomes Indicate That the Oral Microbiome Is Unique Among All Body Sites and Conserved Among Nonhuman Primates
Asangba et al., Microbiology Spectrum. 2022.
https://www.doi.org/10.1128/spectrum.01643-21
Microbiomes are critical to host health and disease, but large gaps remain in the understanding of the determinants, coevolution, and variation of microbiomes across body sites and host species. Thus, researchers conducted the largest comparative study of primate microbiomes to date by investigating microbiome community composition at eight distinct body sites in 17 host species. They found that the oral microbiome is unique in exhibiting notable similarity across primate species while being distinct from the microbiomes of all other body sites and host species. This finding suggests conserved oral microbial niche specialization, despite substantial dietary and phylogenetic differences among primates. Supported by ORIP (P51OD010425, P51OD011107, P40OD010965, R01OD010980), NIA, NIAID, and NICHD.
Early Post-Vaccination Gene Signatures Correlate With the Magnitude and Function of Vaccine-Induced HIV Envelope–Specific Plasma Antibodies in Infant Rhesus Macaques
Vijayan et al., Frontiers in Immunology. 2022.
https://www.doi.org/10.3389/fimmu.2022.840976
An effective vaccine is needed to reduce HIV infections, particularly among younger people. The initiation of an HIV vaccine regimen in early life could allow the development of mature HIV‑specific antibody responses that protect against infection. The investigators compared the effects of two vaccine regimens in infant rhesus macaques (sex not specified). Both vaccines induced a rapid innate response, indicated by elevated inflammatory plasma cytokines and altered gene expression. By performing a network analysis, the investigators identified differentially expressed genes associated with B cell activation. These findings suggest that vaccine-induced immunity can be optimized by modulating specific antibody and T cell responses. Supported by ORIP (P51OD011107), NCI, NIAID, and NIDCR.
Obesity Alters Pathology and Treatment Response in Inflammatory Disease
Bapat et al., Nature. 2022.
https://www.doi.org/10.1038/s41586-022-04536-0
Obesity and metabolic disease have been shown to affect immunotherapeutic outcomes. By studying classical type 2 T helper cells (TH2) in lean and obese male mouse models for atopic dermatitis, investigators found that the biologic therapies protected lean mice but exacerbated disease in obese mice. RNA sequencing and genome analyses revealed decreased activity of nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) in TH2 cells in obese mice when compared to lean mice, indicating that PPARγ is required to prevent aberrant non-TH2 inflammation. Understanding the effects of obesity on immunological disease could inform a potential precision medicine approach to target obesity-induced immune dysregulation. Supported by ORIP (S10OD023689), NIAID, NCI, NIDDK, and NIGMS.
Complex Decay Dynamics of HIV Virions, Intact and Defective Proviruses, and 2LTR Circles Following Initiation of Antiretroviral Therapy
White et al., PNAS. 2022.
https://doi.org/10.1073/pnas.2120326119
In people living with HIV-1 (PLWH) who start antiretroviral therapy (ART), virus in blood decreases rapidly to below detection, but remaining infected cells may become part of the latent reservoir. Researchers investigated viral decay dynamics and identified decay processes with pronounced differences between intact and defective proviruses. Infected cells that survive second-phase decay may down-regulate HIV-1 gene expression and enter the stable latent reservoir. This research provides insight into meaningful latent reservoir markers and mechanisms for elimination of cells with intact viral genomes. Supported by ORIP (R01OD011095) and NIAID.
Dynamics and Origin of Rebound Viremia in SHIV-Infected Infant Macaques Following Interruption of Long-Term ART
Obregon-Perko et al., JCI Insight. 2021.
https://pubmed.ncbi.nlm.nih.gov/34699383/
Animal models that recapitulate human COVID-19 disease are critical for understanding SARS-CoV-2 viral and immune dynamics, mechanisms of disease, and testing of vaccines and therapeutics. A group of male pigtail macaques (PTMs) were euthanized either 6- or 21-days after SARS-CoV-2 viral challenge and demonstrated mild-to-moderate COVID-19 disease. Pulmonary infiltrates were dominated by T cells, virus-targeting T cells were predominantly CD4+, increases in circulating inflammatory and coagulation markers, pulmonary pathologic lesions, and the development of neutralizing antibodies were observed. Collectively, the data suggests PTMs are a valuable model to study COVID-19 pathogenesis and may be useful for testing vaccines and therapeutics. Supported by ORIP (P51OD011104) and NIAID.
Circulating Integrin α4β7+ CD4 T Cells Are Enriched for Proliferative Transcriptional Programs in HIV Infection
Lakshmanappa et al., Federation of European Biochemical Societies Letters. 2021.
https://doi.org/10.1002/1873-3468.14163
HIV preferentially infects α4β7+ CD4 T cells, forming latent reservoirs that contribute to HIV persistence, yet the properties of α4β7+ CD4 T cells are poorly understood. Investigating HIV-infected humans and SHIV-infected rhesus macaques, investigators demonstrated that α4β7+ CD4 T cells in blood are enriched for genes regulating cell cycle progression and cellular metabolism. In contrast, rectal α4β7+ CD4 T cells exhibited a core tissue-residency gene expression program. These features were conserved across primate species, suggesting that the tissue environment influences memory T-cell transcriptional networks. These findings provide an important foundation for understanding the role of α4β7 in HIV infection. Supported by ORIP (K01OD023034, R24OD010976) and NIAID.
PD-1 Blockade and Vaccination Provide Therapeutic Benefit Against SIV by Inducing Broad and Functional CD8+ T Cells in Lymphoid Tissue
Rahman et al., Science Immunology. 2021.
https://doi.org/10.1126/sciimmunol.abh3034
Effective HIV therapies must induce functional CD8+ T cells and clear latent viral reservoirs during antiretroviral therapy (ART). Using a rhesus macaque model, researchers showed that therapeutic vaccination under ART using a CD40L plus TLR7 agonist-adjuvanted DNA/modified vaccinia Ankara vaccine regimen induced robust SIV-specific CD4+ and CD8+ T cell responses. Addition of an anti-PD-1 antibody to the SIV vaccine increased cytotoxic CD8+ T cells in lymph nodes after ART interruption, correlating to the control of virus and prolonged survival compared with the vaccine alone. Thus, combining immune checkpoint blockade with vaccination may be a promising avenue toward an HIV cure. Supported by ORIP (P51OD011132) and NIAID.