Selected Grantee Publications
A Participant-Derived Xenograft Model of HIV Enables Long-Term Evaluation of Autologous Immunotherapies
McCann et al., Journal of Experimental Medicine. 2021.
https://doi.org/10.1084/jem.20201908
HIV-specific CD8+ T cells partially control viral replication but rarely provide lasting protection due to immune escape. Investigators showed that engrafting NSG mice with memory CD4+ T cells from HIV+ donors enables evaluation of autologous T cell responses while avoiding graft-versus-host disease. Treating HIV-infected mice with clinically relevant T cell products reduced viremia. In vivo activity was significantly enhanced when T cells were engineered with surface-conjugated nanogels carrying an Interleukin-15 superagonist but was ultimately limited by the pervasive selection of escape mutations, recapitulating human patterns. This “participant-derived xenograft” model provides a powerful tool for developing T cell-based therapies for HIV. Supported by ORIP (R01OD011095), NIAID, NIDA, NIMH, NINDS, and NCATS.
Tract Pathogen-Mediated Inflammation Through Development of Multimodal Treatment Regimen and Its Impact on SIV Acquisition in Rhesus Macaques
Bochart et al., PLOS Pathogens. 2021.
https://doi.org/10.1371/journal.ppat.1009565
In addition to being premier HIV models, rhesus macaques are models for other infectious diseases and colitis, where background colon health and inflammation may confound results. Starting with the standard specific-pathogen-free (SPF) model, researchers established a gastrointestinal pathogen-free (GPF) colony via multimodal therapy (enrofloxacin, azithromycin, fenbendazole, and paromomycin) to eliminate common endemic pathogens (EPs). This treatment combined with continued pathogen exclusion eliminated common EPs, improved mucosal barriers, and reduced mucosal and systemic inflammation without microbiota disruption. GPF animals challenged with SIV intrarectally demonstrated a more controlled and consistent rate of SIV acquisition, suggesting the value of this model for HIV studies. Supported by ORIP (U42OD023038, P51OD011092), NCI, and NIAID.
Psychosocial Stress Alters the Immune Response and Results in Higher Viral Load During Acute SIV Infection in a Pigtailed Macaque Model of HIV
Guerrero-Martin et al., Journal of Infectious Diseases. 2021.
https://doi.org/10.1093/infdis/jiab252
Social distancing is an important countermeasure for a pandemic, but social isolation may also have adverse health outcomes in the context of infectious diseases, such as HIV. Researchers compared commonly measured parameters of HIV progression between singly and socially housed simian immunodeficiency virus (SIV)-infected pigtailed macaques. Throughout acute SIV infection, singly housed pigtailed macaques had a higher viral load in the plasma and cerebrospinal fluid and demonstrated greater CD4+ T cell declines and more CD4+ and CD8+ T cell activation compared to socially housed macaques. These findings suggest that psychosocial stress could augment the progression of HIV infection. Supported by ORIP (U42OD013117, P40OD013117, K01OD018244), NIAID, NINDS, and NIMH.
Modulation of MHC-E Transport by Viral Decoy Ligands Is Required for RhCMV/SIV Vaccine Efficacy
Verweij et al., Science. 2021.
https://doi.org/10.1126/science.abe9233
Rhesus cytomegalovirus (RhCMV) strain 68-1-vectored simian immunodeficiency virus (SIV) vaccines elicit strong CD8+ T cell responses that can clear SIV infections. Peptides targeted by these T cells are presented on major histocompatibility complex (MHC) II and MHC-E rather than MHC-Ia. Researchers showed that VL9 drives intracellular transport of MHC-E and recognition of RhCMV-infected targets by MHC-E-restricted CD8+ T cells. Specific-pathogen-free (SPF) rhesus macaques vaccinated with a mutant 68-1 RhCMV lacking VL9 showed no priming of MHC-E-restricted CD8+ T cells and no protection against SIV, suggesting that future effective CMV-based HIV vaccines will require MHC-E-restricted CD8+ T cell priming. Supported by ORIP (U42OD023038, P51OD011092), NIAID, and NCI.
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.
Virus Control in Vaccinated Rhesus Macaques Is Associated with Neutralizing and Capturing Antibodies Against the SHIV Challenge Virus but Not with V1V2 Vaccine–Induced Anti-V2 Antibodies Alone
Hessell et al., Journal of Immunology. 2021.
https://doi.org/10.4049/jimmunol.2001010
In the RV144 human immunodeficiency virus (HIV) vaccine trial, the only immune response associated with reduced infection was a high level of antibodies (Abs) targeting the second variable (V2) loop of the HIV envelope protein (Env). The mechanism underlying this suggested contribution of V2 Abs to protection remains unknown. Researchers tested the role of vaccine-induced anti-V2 Abs in rhesus macaques. Three vaccines strategies were designed to induce only V1V2 Abs before simian-human immunodeficiency virus (SHIV) challenge. Vaccine-induced V2 Abs did not independently control SHIV infection. However, neutralizing and virus capture anti-Env Abs were found to correlate with SHIV control. Supported by ORIP (P51OD011092) and NIAID.
Persistence of Viral RNA in Lymph Nodes in ART-suppressed SIV/SHIV-Infected Rhesus Macaques
Cadena et al., Nature Communications. 2021.
https://doi.org/10.1038/s41467-021-21724-0
The long-lived viral reservoir is a key obstacle to curing HIV/AIDS, yet the features of that reservoir during antiretroviral therapy (ART) remain poorly understood. Researchers undertook a comprehensive analysis of the SIV/SHIV reservoir in multiple lymphoid and non-lymphoid tissues from SIV/SHIV-infected rhesus macaques suppressed with ART for one year. Their findings support a model in which the tissue viral reservoir is rapidly and broadly seeded early during acute infection. Viral RNA persists lymphoid tissues despite a long period of suppressive ART. Therefore, viral latency does not appear to be universally transcriptionally silent; the reservoir may include a spectrum of latency depths. Supported by ORIP (R01OD024917) and NIAID.
New SHIVs and Improved Design Strategy for Modeling HIV-1 Transmission, Immunopathogenesis, Prevention, and Cure
Li et al., Journal of Virology. 2021.
https://doi.org/10.1128/JVI.00071-21
Researchers knew that substitution of HIV-1 Env residue 375-serine by aromatic residues enhances binding to rhesus CD4 enabling primary HIV-1 Envs to support replication as simian-human immunodeficiency virus (SHIV) chimeras in rhesus monkeys. The investigators constructed SHIVs containing 10 primary Envs corresponding to HIV-1 subtypes A, B, C, AE, and AG. Only one with histidine at Env375 replicated efficiently in rhesus cells. Replacement of wild-type Env375 residues by tryptophan, tyrosine, phenylalanine, or histidine in the other 9 SHIVs led to efficient replication. These new SHIVs transmit via mucosal routes like HIV-1 and have use for vaccine testing in nonhuman primates. Supported by ORIP (U42OD021458, P40OD012217), NIAID, and NCI.
Polyfunctional Tier 2–Neutralizing Antibodies Cloned Following HIV-1 Env Macaque Immunization Mirror Native Antibodies in a Human Donor
Spencer et al., Journal of Immunology. 2021.
https://doi.org/10.4049/jimmunol.2001082
HIV vaccine efforts are limited by viral strain diversity and the shielding of neutralization epitopes on the viral envelope, yet isolation of broadly neutralizing antibodies from infected individuals suggests the potential for eliciting protective antibodies through vaccination. Researchers cloned 58 monoclonal antibodies (mAbs) from a rhesus monkey immunized with envelope glycoprotein immunogens from an HIV-1 clade C–infected volunteer. Twenty mAbs exhibited some neutralizing activity. Cloned mAbs targeting the V3 region and CD4 binding site were capable of tier 2 (i.e., moderate) neutralization. This study demonstrates partial recapitulation of the human donor’s humoral immune response through nonhuman primate vaccination. Supported by ORIP (P51OD011092) and NIAID.
Modified Adenovirus Prime–Protein Boost Clade C HIV Vaccine Strategy Results in Reduced Viral DNA in Blood and Tissues Following Tier 2 SHIV Challenge
Malherbe et al., Frontiers in Immunology. 2021.
https://doi.org/10.3389/fimmu.2020.626464
Researchers conducted a comparative vaccine challenge study in rhesus macaques. One group of monkeys was vaccinated using co-immunization with DNA Gag and Env expression plasmids and trimeric Env gp140 glycoprotein. The other group was primed with two replicating simian adenovirus-vectored vaccines expressing Gag and boosted with trimeric Env gp140. Both strategies elicited antigen-specific humoral and cellular immune responses, but neither approach provided significant protection from viral acquisition upon repeated mucosal challenges with a heterologous Tier 2 SHIV. Nevertheless, both regimens significantly lowered cell-associated viral DNA in multiple tissues, thus potentially dampening the infection and providing clues for further vaccine development. Supported by ORIP (U42OD023038, P51OD011092) and NIAID.