Selected Grantee Publications
Chronic Immune Activation and Gut Barrier Dysfunction Is Associated with Neuroinflammation in ART-Suppressed SIV+ Rhesus Macaques
Byrnes et al., PLOS Pathogens. 2023.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10085024/
About 40% of people with HIV develop neurocognitive disorders, potentially resulting from persistent infection in the brain and neuroinflammation. Investigators characterized the central nervous system reservoir and immune environment of simian immunodeficiency virus (SIV)–infected rhesus macaques of both sexes during acute, chronic, or antiretroviral therapy (ART)–suppressed infection. They reported that neuroinflammation and blood–brain barrier dysfunction correlated with viremia and immune activation in the gut. Their findings suggest that gastrointestinal tract damage can contribute to neuroimmune activation and inflammation, even in the absence of SIV or HIV infection. This work also has implications for other neurological disorders where chronic inflammation is associated with pathogenesis. Supported by ORIP (P51OD011132, P51OD011092, U42OD011023, R24OD010445), NIAID, NCI, and NIMH.
Human Hematopoietic Stem Cell Engrafted IL-15 Transgenic NSG Mice Support Robust NK Cell Responses and Sustained HIV-1 Infection
Abeynaike et al., Viruses. 2023.
https://www.mdpi.com/1999-4915/15/2/365
A major obstacle to human natural killer (NK) cell reconstitution is the lack of human interleukin‑15 (IL-15) signaling, as murine IL-15 is a poor stimulator of the human IL-15 receptor. Researchers show that immunodeficient NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice expressing a transgene encoding human IL-15 (NSG-Tg(IL-15)) have physiological levels of human IL-15 and support long-term engraftment of human NK cells when transplanted with human umbilical cord blood–derived hematopoietic stem cells (HSCs). These mice demonstrate robust and long-term reconstitution with human immune cells but do not develop graft-versus-host disease, allowing long-term studies of human NK cells. The HSC-engrafted mice can sustain HIV-1 infection, resulting in human NK cell responses. This work provides a robust novel model to study NK cell responses to HIV-1. Supported by ORIP (R24OD026440), NIAID, NCI, and NIDDK.
IL-21 Enhances Influenza Vaccine Responses in Aged Macaques with Suppressed SIV Infection
Kvistad et al., JCI Insight. 2021.
https://doi.org/10.1172/jci.insight.150888
Aging with HIV is associated with low-grade systemic inflammation, immune senescence, and impaired antibody (Ab) responses to such vaccines as influenza (flu). Researchers investigated the role of interleukin (IL)-21, a CD4 T follicular helper cell regulator, on flu vaccine Ab response in rhesus macaques in the context of age and controlled simian immunodeficiency virus (SIV) mac239 infection. They found that IL-21 enhanced flu vaccine-induced Ab responses in SIV+ (anti-retroviral therapy-suppressed) aged rhesus macaques, adjuvanting the flu vaccine by modulating lymph node germinal center activity. Thus, strategies to supplement IL-21 in aging might improve vaccine responses in people aging with HIV. Supported by ORIP (R24OD010947) 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.
Tissue-Specific Transcriptional Profiling of Plasmacytoid Dendritic Cells Reveals a Hyperactivated State in Chronic SIV Infection
Lee et al., PLOS Pathogens. 2021.
https://doi.org/10.1371/journal.ppat.1009674
Persistent immune activation is an obstacle to optimal health for people living with HIV. Using RNA sequencing, researchers investigated the immunostimulatory potential of plasmacytoid dendritic cells (pDCs) in chronic SIV infection in rhesus macaques. They observed that pDCs have highly activated profiles in these animals. In contrast, pDCs from SIV-infected sooty mangabeys (natural hosts for SIV) had expression profiles similar to uninfected animals. In chronically infected rhesus macaques, interferon alpha transcripts were readily detected in lymph node-homing pDCs, but not those from blood. Therefore, pDCs are a major producer of type-I interferon in chronic SIV infection and could be a useful immunotherapy target. Supported by ORIP (R24OD010445, P51OD011132, P51OD011092, S10OD026799) and NIAID.
IL-21 and IFNα Therapy Rescues Terminally Differentiated NK Cells and Limits SIV Reservoir in ART-Treated Macaques
Harper et al., Nature Communications. 2021.
https://doi.org/10.1038/s41467-021-23189-7
Nonpathogenic simian immunodeficiency virus (SIV) infections in natural hosts, such as vervet monkeys, are characterized by a lack of gut microbial translocation, robust secondary lymphoid natural killer cell responses, and limited SIV dissemination in lymph node B-cell follicles. Using antiretroviral therapy-treated, SIV-infected rhesus monkeys—a pathogenic model—researchers showed that interleukin-21 and interferon alpha therapy generate terminally differentiated blood natural killer cells with potent human leukocyte antigen-E-restricted activity in response to SIV envelope peptides. The correlated reduction of replication-competent SIV in lymph node demonstrates that vervet-like natural killer cell differentiation can be rescued in rhesus monkeys to promote viral clearance. Supported by ORIP (P51OD011132, R24OD010947), NIAID, and NCI.
Antibody-Mediated Depletion of Viral Reservoirs is Limited in SIV-Infected Macaques Treated Early With Antiretroviral Therapy
Swanstrom et al., Journal of Clinical Investigation. 2021.
https://doi.org/10.1172/JCI142421
Virus-specific strategies to target the latent HIV reservoir in individuals on combination antiretroviral therapy (cART) have been limited by inefficient induction of viral protein expression. Researchers used rhesus macaques to investigate an antibody-mediated reservoir targeting strategy, targeting the CD4 molecule rather than a viral protein, to deplete potential viral target cells irrespective of infection status. Despite profound CD4+ T cell depletion in blood and lymph nodes, time to viral rebound following cART cessation was not delayed in anti-CD4 treated animals compared with controls, likely due to the limited antibody-mediated cell depletion that occurred in rectal tissue and lymphoid follicles. Supported by ORIP (R24OD010976), NCI, and NIAID.
Epidemiological and Molecular Characterization of a Novel Adenovirus of Squirrel Monkeys After Fatal Infection During Immunosuppression
Rogers et al., Microbial Genomics. 2020.
https://pubmed.ncbi.nlm.nih.gov/32614763/
Adenoviruses frequently cause upper respiratory tract infections, often causing disseminated disease in immunosuppressed patients. A novel adenovirus was identified, squirrel monkey adenovirus 1 (SqMAdV-1), as the cause of a fatal infection in an immunocompromised squirrel monkey (Saimiri boliviensis). A nucleotide polymorphism at the stop codon of the DNA polymerase gene results in a 126 amino acid extension at the carboxy terminus. A single adenovirus variant, SqMAdV-3, has similarity to tufted capuchin (Sapajus apella) adenoviruses. The largest group of adenovirus variants detected, SqMAdV-2.0-2.16, has high similarity (93-99%) to the TMAdV, suggesting that squirrel monkeys may be the natural host of the TMAdV. Supported by ORIP (P40OD010938, R24OD018553), and NIAID.