Selected Grantee Publications
Protection of Newborn Macaques by Plant-Derived HIV Broadly Neutralizing Antibodies: A Model for Passive Immunotherapy During Breastfeeding
Rosenberg et al., Journal of Virology. 2021.
https://doi.org/10.1128/JVI.00268-21
Preventing vertical transmission of HIV to newborns is an unmet medical need in resource poor countries. Using a breastfeeding macaque model with multiple simian-human immunodeficiency virus challenge, researchers assessed the protective efficacy of two human broadly neutralizing antibodies (bnAbs) against HIV, PGT121 and VRC07-523, which are produced by a plant expression system. Despite the transient presence of plasma viral RNA, the bnAbs prevented productive infection in all newborns with no sustained plasma viremia, compared to viral loads ranging from 103 to 5x108 in four untreated controls. Thus, plant-expressed antibodies show promise as passive immunoprophylaxis in a breastfeeding model in newborns. Supported by ORIP (U42OD023038, P51OD011092) 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.
Gut Germinal Center Regeneration and Enhanced Antiviral Immunity by Mesenchymal Stem/Stromal Cells
Weber et al., JCI Insight. 2021.
https://doi.org/10.1172/jci.insight.149033
Researchers investigated the effects of mesenchymal stem/stromal cell (MSC) infusions on gut mucosal recovery, antiviral immunity, and viral suppression in SIV-infected rhesus macaques. MSC treatment heightened virus-specific responses and reduced viral load. Clearance of SIV-positive cells from gut mucosal effector sites was correlated with regeneration of germinal centers, restoration of follicular B cells and T follicular helper cells, and enhanced antigen presentation by viral trapping within the follicular dendritic cell network. These changes were associated with enhanced gene expression for type I/II interferon signaling, B cell proliferation, and interleukin 7. MSC treatment also activated metabolic pathways associated with enhanced immunity and viral reduction. Supported by ORIP (P51OD011107) and NIAID.
Antibody-Based CCR5 Blockade Protects Macaques From Mucosal SHIV Transmission
Chang et al., Nature Communications. 2021.
https://doi.org/10.1038/s41467-021-23697-6
The efficacy of antiretroviral therapy (ART) as pre-exposure prophylaxis against HIV is hindered by incomplete patient adherence and ART-resistant variants. Researchers found that competitive inhibition of HIV Env-CCR5 binding via the CCR5-specific antibody Leronlimab protects rhesus macaques against infection following repeated intrarectal challenges with a CCR5-tropic simian-human immunodeficiency virus (SHIVSF162P3). Biweekly injection of Leronlimab at 50 mg/kg provided complete protection from SHIV infection. Tissue biopsies from protected macaques post-challenge revealed complete CCR5 receptor occupancy and an absence of viral DNA. After Leronlimab washout, transfer of hematologic cells into naïve monkeys did not transmit infection, supporting the initiation of clinical trials. Supported by ORIP (P51OD011092, K01OD026561, P40OD028116) 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.
Postpubertal Spermatogonial Stem Cell Transplantation Restores Functional Sperm Production in Rhesus Monkeys Irradiated Before and After Puberty
Shetty et al., Andrology. 2021.
https://onlinelibrary.wiley.com/doi/10.1111/andr.13033
Cancer treatment of prepubertal patients impacts future fertility due to the abolition of spermatogonial stem cells (SSCs). Prepubertal rhesus monkeys (n=6) were unilaterally castrated, and the remaining testes irradiated twice to insure loss of SSCs; the animals were treated with a vehicle or GnRH antagonist for 8 weeks (n=3/treatment). The cryopreserved prepubertal testicular tissue was allergenically transplanted into the intact testes of the monkeys after puberty. Recovery of viable donor epididymal sperm was observed in half the monkeys. These results illustrate that sperm production can be restored in primates by transplantation of testicular cells from cryopreserved untreated prepubertal testes into seminiferous tubules of the remaining testes. Supported by ORIP (P51OD011092), NICHD, and NCI.
Evidence in Primates Supporting the Use of Chemogenetics for the Treatment of Human Refractory Neuropsychiatric Disorders
Roseboom et al., Molecular Therapy. 2021.
https://doi.org/10.1016/j.ymthe.2021.04.021
A rhesus macaque model for pathological anxiety was used to investigate the feasibility of decreasing anxiety using chemogenetics, known as DREADDs (designer receptors exclusively activated by designer drugs), to reduce amygdala neuronal activity. A low-dose clozapine administration strategy was developed to induce DREADD-mediated amygdala inhibition. Compared to controls, clozapine selectively decreased anxiety-related freezing behavior in the human intruder paradigm in the chemogentic monkeys, while coo vocalizations and locomotion were unaffected. These results are an important step in establishing chemogenetic strategies for patients with refractory neuropsychiatric disorders in which amygdala alterations are central to disease pathophysiology. Supported by ORIP (P51OD011106), NIMH, and NICHD.
Functional Convergence of a Germline-Encoded Neutralizing Antibody Response in Rhesus Macaques Immunized with HCV Envelope Glycoproteins
Chen et al., Immunity. 2021.
https://doi.org/10.1016/j.immuni.2021.02.013
Immunoglobulin heavy chain variable gene IGHV1-69-encoded broadly neutralizing antibodies (bnAbs) targeting the hepatitis C virus (HCV) envelope glycoprotein (Env) E2 are important for protection against HCV infection in humans. An IGHV1-69 ortholog, VH1.36, is preferentially used for bnAbs isolated from rhesus macaques immunized against HCV Env. Researchers investigated the genetic, structural, and functional properties of VH1.36-encoded bnAbs generated by HCV Env vaccination of macaques and compared their findings to IGHV1-69-encoded bnAbs from HCV patients. The investigators found that macaque VH1.36- and human IGHV1-69-encoded bnAbs share many common features, which provides an excellent framework for rational HCV vaccine design and testing. Supported by ORIP (P51OD011133, U42OD010442), NIAID, NCI, and NIGMS.
Sensitive Tracking of Circulating Viral RNA Through All Stages of SARS-CoV-2 Infection
Huang et al., Journal of Clinical Investigation. 2021.
https://www.jci.org/articles/view/146031
Circulating SARS-CoV-2 RNA could represent a more reliable indicator of infection than nasal RNA, but quantitative reverse transcription PCR (RT-qPCR) lacks diagnostic sensitivity for blood samples. Researchers developed a CRISPR-amplified, blood-based COVID-19 (CRISPR-ABC) assay to detect SARS-CoV-2 in plasma. They evaluated the assay using samples from SARS-CoV-2-infected African green monkeys and rhesus macaques, as well as from COVID-19 patients. CRISPR-ABC consistently detected viral RNA in the plasma of the experimentally infected primates from 1 to 28 days after infection. The increases in plasma SARS-CoV-2 RNA in the monkeys preceded rectal swab viral RNA increases. In the patient cohort, the new assay demonstrated 91.2% sensitivity and 99.2% specificity versus RT-qPCR nasopharyngeal testing, and it also detected COVID-19 cases with transient or negative nasal swab RT-qPCR results. These findings suggest that detection of SARS-CoV-2 RNA in blood by CRISPR-augmented RT-PCR could improve COVID-19 diagnosis, facilitate the evaluation of SARS-CoV-2 infection clearance, and help predict the severity of infection. Supported by ORIP (P51OD011104).
Cytomegaloviral Determinants of CD8+ T Cell Programming and RhCMV/SIV Vaccine Efficacy
Malouli et al., Science Immunology. 2021.
https://www.science.org/doi/10.1126/sciimmunol.abg5413
Cytomegalovirus (CMV)-based vaccine vectors were developed to leverage the ability of CMVs to elicit sustained CD4+ and CD8+ T cell responses with broad tissue distribution. The 68-1 rhesus cytomegalovirus (RhCMV) vectors that express simian immunodeficiency virus (SIV) inserts induce major histocompatibility complex E (MHC-E)- and MHC-II-restricted, SIV-specific CD8+T cell responses. The contribution of this unconventional MHC restriction to RhCMV/SIV vaccine efficacy are poorly understood. Researchers demonstrated that these responses result from genetic rearrangements in 68-1 RhCMV that disrupt the function of eight immunomodulatory proteins encoded by the virus. Repair of each of these genes with either RhCMV or human CMV counterparts shifted responses to MHC-Ia-restricted, or MHC-Ia- and MHC-II-restricted, CD8 T cell responses, but repairing the RhCMV genes did not protect against SIV. These findings suggest that MHC-E-restricted CD8+ T cell responses may be critical to protection against SIV. Supported by ORIP (U42OD023038, P51OD011092).