Selected Grantee Publications
- Clear All
- 49 results found
- Nonhuman Primate Models
- 2022
Infection Order Outweighs the Role of CD4+ T Cells in Tertiary Flavivirus Exposure
Marzan-Rivera et al., iScience. 2022.
https://www.doi.org/10.1016/j.isci.2022.104764
The link between CD4+ T and B cells in immune responses to Dengue virus (DENV) and Zika virus (ZIKV) and their roles in cross-protection during heterologous infection are poorly known. The authors used CD4+ lymphocyte depletions to dissect the impact of cellular immunity on humoral responses during tertiary flavivirus infection in male macaques. CD4+ depletion in DENV/ZIKV–primed animals, followed by DENV, resulted in dysregulated adaptive immune responses. They show a delay in DENV-specific antibody titers and binding and neutralization in the DENV/ZIKV–primed, CD4-depleted animals but not in ZIKV/DENV–primed, CD4-depleted animals. This study confirms the role of CD4+ cells in priming an early humoral response during sequential flavivirus infections and suggests that the order of exposure affects the outcome of a tertiary infection. Supported by ORIP (P40OD012217), NIAID, and NIGMS.
A Clade C HIV-1 Vaccine Protects Against Heterologous SHIV Infection by Modulating IgG Glycosylation and T Helper Response in Macaques
Sahoo et al., Science Immunology. 2022.
https://www.doi.org/10.1126/sciimmunol.abl4102
Vaccines for HIV-1 capable of generating a broadly cross-reactive neutralizing antibody response are needed urgently. The researchers tested the protective efficacy of a clade C HIV-1 vaccination regimen in male rhesus macaques. The vaccine was administered either orally using a needle-free injector or via parenteral injection. Significant protection was observed for both vaccination routes following the simian–human immunodeficiency virus (SHIV) challenge, with an estimated efficacy of 68% per exposure. The glycosylation profile of IgG and HIV-resistant helper T cell response contributes to the protection. Supported by ORIP (P51OD011132), NIAID, and NIDCR.
Allogeneic MHC‑Matched T‑Cell Receptor Α/Β‑Depleted Bone Marrow Transplants in SHIV‑Infected, ART‑Suppressed Mauritian Cynomolgus Macaques
Weinfurter et al., Scientific Reports. 2022.
https://www.doi.org/10.1038/s41598-022-16306-z
Allogeneic hematopoietic stem cell transplants are effective in reducing HIV reservoirs following antiretroviral therapy (ART). A better understanding of this mechanism could enable the development of safer and more efficacious HIV treatment regimens. In this study, the researchers used a Mauritian cynomolgus macaque model to study the effects of allogeneic major histocompatibility complex–matched α/β T cell–depleted bone marrow cell transplantation following infection with simian–human immunodeficiency virus (SHIV). The macaques began ART 6 to 16 weeks post-infection. In three of the four macaques, SHIV DNA was undetectable in blood but persisted in other tissues. These results suggest that extended ART likely is needed to eradicate the HIV reservoir following transplantation. In future studies, full donor engraftment should be balanced with suppression of graft-versus-host disease. Supported by ORIP (P51OD011106, R24OD021322), and NCI.
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.
Myeloid Cell Tropism Enables MHC-E–Restricted CD8+ T Cell Priming and Vaccine Efficacy by the RhCMV/SIV Vaccine
Hansen et al., Science Immunology. 2022.
https://www.doi.org/10.1126/sciimmunol.abn9301
Simian immunodeficiency virus (SIV) vaccines based on strain 68-1 rhesus cytomegalovirus vectors have been shown to arrest viral replication early in primary infection. The specific characteristics underlying this effect are not understood fully. In this study, the researchers used host microRNA–mediated vector tropism restriction to demonstrate that the targeted responses are dependent on vector infection of distinct cell types in a rhesus macaque model. Only vectors programmed to elicit major histocompatibility complex E–restricted CD8+ T cell responses provided protection against SIV challenge. These findings could be applied in the development of other vaccines for cancers and infectious diseases. Supported by ORIP (P51OD011092), NCI, 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.
The Ex Vivo Pharmacology of HIV-1 Antiretrovirals Differs Between Macaques and Humans
Herrera et al., iScience. 2022.
https://www.doi.org/10.1016/j.isci.2022.104409
Nonhuman primates (NHPs) are used widely for studies of antiretroviral (ARV)–based pre‑exposure prophylaxis (PrEP), but more work is needed to address dose–efficacy discrepancies between NHP studies and human clinical trials of PrEP candidates. Investigators explored the use of colorectal and cervicovaginal ex vivo mucosal tissue explants as a bridging model between NHPs and humans. They reported differences in inhibitory potency of drug combinations between NHP and human mucosal tissue explants. These findings suggest that tissue explants can help researchers refine and interpret NHP ARV studies. Supported by ORIP (P51OD011104) and NIAID.
Altered Expression of ACE2 and Co-Receptors of SARS-CoV-2 in the Gut Mucosa of the SIV Model of HIV/AIDS
Hu et al., Frontiers in Microbiology. 2022.
https://www.doi.org/10.3389/fmicb.2022.879152
The investigators assessed the influence of pre-existing HIV infection—which is known to target the gut mucosal immune system—on the vulnerability to SARS-CoV-2 infection and disease. Using a rhesus macaque model (sex not specified), they investigated changes in the expression of ACE2 and other SARS-CoV-2 receptors and related pathways. Simian immunodeficiency virus (SIV) infection resulted in sustained or increased ACE2 expression in an inflamed and immune-impaired gut mucosal microenvironment. These changes are likely to increase susceptibility to SARS-CoV-2 infection and disease severity. Taken together, these results demonstrate the utility of SIV models to fill knowledge gaps related to HIV infection and coinfections. Supported by ORIP (P51OD011107) and NIAID.
Generation of SIV-Resistant T Cells and Macrophages from Nonhuman Primate Induced Pluripotent Stem Cells with Edited CCR5 Locus
D’Souza et al., Stem Cell Reports. 2022.
https://www.doi.org/10.1016/j.stemcr.2022.03.003
Genetically modified T cells have shown promise as a potential therapy for HIV. A renewable source of T cells from induced pluripotent stem cells (iPSCs) could help to further research progress in this area. The researchers used Mauritian cynomolgus macaques to generate simian immunodeficiency virus (SIV)–resistant T cells and macrophages from iPSCs. These engineered cells demonstrated impaired capacity for differentiation into CD4+CD8+ T cells. T cells and macrophages from the edited iPSCs did not support SIV replication. These findings could be applied to the development of new HIV therapies. Supported by ORIP (R24OD021322, P51OD011106) and NHLBI.