Dynamics and Origin of Rebound Viremia in SHIV-Infected Infant Macaques Following Interruption of Long-Term ART
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Animal models that recapitulate human COVID-19 disease are critical for understanding SARS-CoV-2 viral and immune dynamics, mechanisms of disease, and testing of vaccines and therapeutics. A group of male pigtail macaques (PTMs) were euthanized either 6- or 21-days after SARS-CoV-2 viral challenge and demonstrated mild-to-moderate COVID-19 disease.
Antiretroviral Therapy Timing Impacts Latent Tuberculosis Infection Reactivation in a Tuberculosis/Simian Immunodeficiency Virus Coinfection Model
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In the rhesus macaque model for Mycobacterium tuberculosis plus simian immunodeficiency virus (SIV) co-infection, chronic immune activation rather than depletion of CD4+ T cells correlates with reactivation of latent tuberculosis infection (LTBI). Researchers administered combined antiretroviral therapy (cART) at 2 weeks post-SIV co-infection to study whether restoration of CD4+ T cell immunity occurred more broadly, and whether this prevented LTBI compared to cART initiated at 4 weeks post-SIV.
Monoclonal Antibodies Protect Aged Rhesus Macaques From SARS-CoV-2-Induced Immune Activation and Neuroinflammation
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In aged diabetic female rhesus macaques, prophylactic administration of neutralizing monoclonal antibodies (mAbs) effectively limits SARS-CoV-2 replication in both the upper and lower respiratory tract, and decreases immune activation, including reducing interferon-induced chemokines and limiting effector CD4 T cell influx into the cerebrospinal fluid.
Blastocyst Development After Fertilization with In Vitro Spermatids Derived From Nonhuman Primate Embryonic Stem Cells
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Rhesus macaque pluripotent stem cells were differentiated into spermatogenic germ cell linages and matured in vitro to form spermatids that were capable of fertilizing oocytes (female or germ cells involved in reproduction) by intracytoplasmic spermatid injection (i.e., the egg is fertilized outside the body and the sperm is injected through a needle into the egg). Successful in vitro preimplantation embryo development was observed in approximately 12% of zygotes. The data suggest potential mechanisms to address male infertility.
Deciphering the Role of Mucosal Immune Responses and the Cervicovaginal Microbiome in Resistance to HIV Infection in HIV-Exposed Seronegative Women
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Identifying correlates of protection in HIV-exposed seronegative (HESN) individuals requires identification of HIV-specific local immune responses. Researchers performed a comprehensive investigation of the vaginal mucosa and cervicovaginal microbiome in HESN women. They found elevated antiviral cytokines, soluble immunoglobulins, activated NK cells, CXCR5+ CD8+ T cells, and T follicular helper cells in HESN women compared to HIV-unexposed healthy women. They also found greater bacterial diversity and increased abundance of Gardnerella species in the mucosa of HESN women.
CD4+ T Cells Are Dispensable for Induction of Broad Heterologous HIV Neutralizing Antibodies in Rhesus Macaques
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Researchers investigated the humoral response in vaccinated rhesus macaques with CD4+ T cell depletion, using the VC10014 DNA protein co-immunization vaccine platform (with gp160 plasmids and gp140 trimeric proteins derived from an HIV-1 infected subject). Both CD4+-depleted and non-depleted animals developed comparable Tier 1 and 2 heterologous HIV-1 neutralizing plasma antibody titers. Thus, primates generate HIV neutralizing antibodies in the absence of robust CD4+ T cell help, which has important implications for vaccine development.
Comparative Cellular Analysis of Motor Cortex in Human, Marmoset and Mouse
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Investigators used high-throughput transcriptomic and epigenomic profiling of more than 450,000 single nuclei in humans, marmosets, and mice, to characterize the cellular makeup of the primary motor cortex (M1), which exhibits similarities that mirror evolutionary distance and are consistent between the transcriptome and epigenome. Despite the overall conservation, many species-dependent specializations are apparent.
A Novel Non-Human Primate Model of Pelizaeus-Merzbacher Disease
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Pelizaeus-Merzbacher disease (PMD) in humans is a severe hypomyelinating disorder of the central nervous system (CNS) linked to mutations in the proteolipid protein-1 (PLP1) gene. Investigators report on three spontaneous cases of male neonatal rhesus macaques (RMs) with clinical symptoms of hypomyelinating disease. Genetic analysis revealed that the parents of these related RMs carried a rare, hemizygous missense variant in exon 5 of the PLP1 gene.
Prior Infection With SARS-CoV-2 WA1/2020 Partially Protects Rhesus Macaques Against Re-Infection With B.1.1.7 and B.1.351 Variants
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Using the rhesus macaque model, researchers addressed whether natural immunity induced by the original SARS-CoV-2 WA1/2020 strain protects against re-challenge with B.1.1.7 and B.1.351, known as the alpha and beta variants of concern, respectively. The investigators infected rhesus macaques with WA1/2020 and re-challenged them on day 35 with WA1/2020 or with the alpha or beta variants. Natural immunity to WA1/2020 led to robust protection against re-challenge with WA1/2020, partial protection against beta, and an intermediate degree of protection against alpha.
Improving Rigor and Reproducibility in Nonhuman Primate Research
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Investigators across interdisciplinary fields consider approaches to enhance rigor and producibility in nonhuman primate (NHP) research. Given their similarity to humans, NHPs are often the animal model of choice for translational/preclinical biomedical research. However, availability of NHPs is limited. Hence, increased rigor is required to maximize the information gained from NHP studies.