Altered Expression of ACE2 and Co-Receptors of SARS-CoV-2 in the Gut Mucosa of the SIV Model of HIV/AIDS
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The investigators assessed the influence of pre-existing HIV infection—which is known to target the gut mucosal immune system—on the vulnerability to SARS-CoV-2 infection and disease. Using a rhesus macaque model (sex not specified), they investigated changes in the expression of ACE2 and other SARS-CoV-2 receptors and related pathways. Simian immunodeficiency virus (SIV) infection resulted in sustained or increased ACE2 expression in an inflamed and immune-impaired gut mucosal microenvironment.
Generation of SIV-Resistant T Cells and Macrophages from Nonhuman Primate Induced Pluripotent Stem Cells with Edited CCR5 Locus
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Genetically modified T cells have shown promise as a potential therapy for HIV. A renewable source of T cells from induced pluripotent stem cells (iPSCs) could help to further research progress in this area. The researchers used Mauritian cynomolgus macaques to generate simian immunodeficiency virus (SIV)–resistant T cells and macrophages from iPSCs. These engineered cells demonstrated impaired capacity for differentiation into CD4+CD8+ T cells. T cells and macrophages from the edited iPSCs did not support SIV replication.
Adverse Biobehavioral Effects in Infants Resulting from Pregnant Rhesus Macaques’ Exposure to Wildfire Smoke
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Exposure to wildfire smoke (WFS) is a growing health concern as wildfires increase in number and size due to climate change. Researchers found that developing rhesus monkeys exposed to WFS from the Camp Fire in California (November 2018) during the first third of gestation exhibited greater inflammation, blunted cortisol, more passive behavior, and memory impairment compared to animals conceived after smoke had dissipated. Analysis of a historical control cohort did not support the alternative hypothesis that conception timing alone explained the results.
Antimicrobial Prophylaxis Does Not Improve Post-Surgical Outcomes in SIV/SHIV–Uninfected or SIV/SHIV–Infected Macaques (Macaca mulatta and Macaca fascicularis) Based on a Retrospective Analysis
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Some institutions routinely administer antimicrobial prophylaxis to nonhuman primates prior to surgery to prevent surgical site infections. In this study, the investigators assessed the influence of antimicrobial prophylaxis on complication rates in macaques of both sexes receiving peripheral lymph node (PLN) and laparoscopic biopsies. After PLN biopsies, no significant differences were observed between animals that received antimicrobial prophylaxis and those that did not. After laparoscopic biopsies, complication rates were greater in animals that received antimicrobial prophylaxis.
Early Post-Vaccination Gene Signatures Correlate With the Magnitude and Function of Vaccine-Induced HIV Envelope–Specific Plasma Antibodies in Infant Rhesus Macaques
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An effective vaccine is needed to reduce HIV infections, particularly among younger people. The initiation of an HIV vaccine regimen in early life could allow the development of mature HIV‑specific antibody responses that protect against infection. The investigators compared the effects of two vaccine regimens in infant rhesus macaques (sex not specified). Both vaccines induced a rapid innate response, indicated by elevated inflammatory plasma cytokines and altered gene expression.
A Potent Myeloid Response Is Rapidly Activated in the Lungs of Premature Rhesus Macaques Exposed to Intra-Uterine Inflammation
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Up to 40% of preterm births are associated with histological chorioamnionitis (HCA), which can lead to neonatal mortality, sepsis, respiratory disease, and neurodevelopmental problem. Researchers used rhesus macaques to comprehensively describe HCA-induced fetal mucosal immune responses and delineate the individual roles of IL-1β and TNFα in HCA-induced fetal pathology. Their data indicate that the fetal innate immune system can mount a rapid, multifaceted pulmonary immune response to in utero exposure to inflammation.
Presence of Natural Killer B Cells in Simian Immunodeficiency Virus–Infected Colon That Have Properties and Functions Similar to Those of Natural Killer Cells and B Cells but Are a Distinct Cell Population
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HIV infection of the gut is associated with increased mucosal inflammation, and the role of natural killer B (NKB) cells in this process requires further investigation. In this study, the researchers used rhesus and cynomolgus macaque models to characterize the function and characteristics of NKB cells in response to simian immunodeficiency virus (SIV) infection. They reported that NKB cells can kill target cells, proliferate, and express several inflammatory cytokines.
Phagocytosis by an HIV Antibody Is Associated with Reduced Viremia Irrespective of Enhanced Complement Lysis
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Researchers used the bNAb 10E8v4 targeting the HIV Env protein to examine the role of antibody-mediated effector and complement (C′) activity when 10E8v4 was administered prophylactically to rhesus monkeys challenged with simian-human immunodeficiency virus (SHIV). With sub-protective dosing, the researchers found a 78–88% reduction in post-acute viremia that was associated with 10E8v4–mediated phagocytosis.
Vaccine-Induced, High-Magnitude HIV Env-Specific Antibodies with Fc-Mediated Effector Functions Are Insufficient to Protect Infant Rhesus Macaques against Oral SHIV Infection
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A tailored, effective HIV vaccine is needed to prevent mother-to-child viral transmission. In nonhuman primate models, infection with simian–human immunodeficiency virus (SHIV) can be prevented by administering broadly neutralizing HIV envelope (Env)–specific antibodies. Investigators tested the efficacy of an intramuscular vaccine regimen against SHIV infection in male and female infant rhesus macaques. The vaccine induced Env-specific antibodies in plasma, with antibody-dependent cellular cytotoxicity and phagocytic function.
CAR/CXCR5–T Cell Immunotherapy Is Safe and Potentially Efficacious in Promoting Sustained Remission of SIV Infection
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HIV and simian immunodeficiency virus (SIV) replication are concentrated within the B cell follicles of secondary lymphoid tissues. In this study, the researchers developed immunotherapeutic chimeric antigen receptor (CAR) T cells that home to follicles and clear SIV-infected cells in a rhesus macaque model. The CAR T cells localized to the follicle, replicated, and interacted directly with infected cells. Most of the treated animals maintained lower viral loads in the blood and follicles, compared to control animals.