Selected Grantee Publications
Recrudescence of Natural Coccidioidomycosis During Combination Antiretroviral Therapy in a Pigtail Macaque Experimentally Infected with Simian Immunodeficiency Virus
Guerriero et al., AIDS Research and Human Retroviruses. 2021.
https://doi.org/10.1089/AID.2020.0228
Coccidioidomycosis is a common fungal infection in people living with HIV, particularly in regions where Coccidioides is endemic, such as the U.S. Southwest. Researchers diagnosed a recrudescent case of previously treated, naturally occurring coccidioidomycosis in a pigtail macaque experimentally infected with simian immunodeficiency virus (SIV) and virally suppressed on combination antiretroviral therapy (cART). Coccidioides IgG antibody titer became detectable before discontinuation of cART, but symptomatic coccidioidomycosis developed after cART withdrawal. This animal was screened and treated in accordance with the guidelines for coccidioidomycosis prevention and treatment. The researchers conclude that macaques with coccidioidomycosis history should be excluded from HIV studies. Supported by ORIP (P51OD010425), NIAID, and NIMH.
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.
Immune Inactivation of Anti-Simian Immunodeficiency Virus Chimeric Antigen Receptor T Cells in Rhesus Macaques
Haeseleer et al., Molecular Therapy–Methods & Clinical Development. 2021.
https://doi.org/10.1016/j.omtm.2021.06.008
Chimeric antigen receptor (CAR) T cell therapies are under development as potential HIV cures. Researchers found that CAR T cells expressing a single-chain variable fragment (scFv) that recognizes V1 or V3 of the SIV envelope eliminated SIV-infected T cells in vitro. However, in vivo infusion of these CAR T cells in rhesus macaques resulted in no detectable antiviral activity. Anti-SIV IgG antibodies in the SIV-infected animals were associated with inhibited CAR T cell effector functions. Thus, lack of in vivo efficacy of CAR T cells might be due to antibodies blocking the interaction between the CAR scFv and its epitope. Supported by ORIP (P51OD011092) 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.
In Vitro and In Vivo Functions of SARS-CoV-2 Infection-Enhancing and Neutralizing Antibodies
Li et al., Cell. 2021.
https://doi.org/10.1016/j.cell.2021.06.021
Antibody-dependent enhancement of infection is a concern for clinical use of antibodies. Researchers isolated neutralizing antibodies against the receptor-binding domain (RBD) or N-terminal domain (NTD) of SARS-CoV-2 spike from COVID-19 patients. Cryo-electron microscopy of RBD and NTD antibodies demonstrated function-specific binding modes. RBD and NTD antibodies mediated both neutralization and infection enhancement in vitro. However, infusion of these antibodies into mice or macaques resulted in suppression of virus replication, demonstrating that antibody-enhanced infection in vitro does not necessarily predict enhanced infection in vivo. RBD-neutralizing antibodies having cross-reactivity against coronaviruses were protective against SARS-CoV-2, the most potent of which was DH1047. Supported by ORIP (P40OD012217, U42OD021458, S10OD018164), NIAID, NCI, NIGMS, and NIH Common Fund.
SARS-CoV-2 Vaccines Elicit Durable Immune Responses in Infant Rhesus Macaques
Garrido et al., Science Immunology. 2021.
https://immunology.sciencemag.org/content/6/60/eabj3684
The immunogenicity of two SARS-CoV-2 vaccines was evaluated in both sexes of infant rhesus macaques (n=8/group). Neither vaccine, stabilized prefusion SARS-CoV-2 S-2P spike (S) protein encoded by mRNA encapsulated in lipid nanoparticles or the purified S protein mixed with 3M-052, a synthetic TLR7/8 agonist in a squalene emulsion, induced adverse effects. Both elicited high magnitude neutralizing antibody titers peaking at week 6. S-specific T cell responses were dominated by IL-17, IFN-γ, or TNF-α. Antibody and cellular responses were stable through week 22. These data provide proof-of concept for a pediatric SARS-CoV-2 vaccine with the potential for durable immunity to decrease transmission of COVID-19. Supported by ORIP (P51OD011107), NIAID, and NCI.
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.
Neutralizing Antibody Vaccine for Pandemic and Pre-Emergent Coronaviruses
Saunders et al., Nature. 2021.
https://doi.org/10.1038/s41586-021-03594-0
SARS-CoV-2 is a new member of the betacoronavirus (beta-CoV) genus, which also includes two common mild beta-CoVs and the life-threatening SARS-CoV-1 and MERS-CoV. Vaccines that elicit protective immunity against SARS-CoV-2 and beta-CoVs that circulate in animals could prevent future pandemics. Researchers designed a novel 24-mer SARS-CoV-2 receptor binding domain-sortase A conjugated nanoparticle vaccine (RBD-scNP). Investigators demonstrated that the immunization of macaques with RBD-scNP, and adjuvanted with 3M-052 and alum, elicits cross-neutralizing antibody responses against bat coronaviruses, SARS-CoV, and multiple SARS-CoV-2 variants of concern. This pioneering approach serves as a multimeric protein platform for the further development of generalized anti-beta-CoV vaccines. Supported by ORIP (U42OD021458), NIAID, and NCI.
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.