Early Treatment With a Combination of Two Potent Neutralizing Antibodies Improves Clinical Outcomes and Reduces Virus Replication and Lung Inflammation in SARS CoV-2 Infected Macaques
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The therapeutic efficacy of a combination of two SARS-CoV-2 monoclonal antibodies (mAbs), C135-LS and C144-LS, were investigated in young adult macaques (3 groups of 4 animals; equal sex distribution). Animals were treated intravenously with low or high doses of C135-LS and C144-LS mAbs or control mAb 24 hours post-infection with SARS-CoV-2.
In Vitro and In Vivo Functions of SARS-CoV-2 Infection-Enhancing and Neutralizing Antibodies
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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.
SARS-CoV-2 Vaccines Elicit Durable Immune Responses in Infant Rhesus Macaques
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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.
Neutralizing Antibody Vaccine for Pandemic and Pre-Emergent Coronaviruses
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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).
Nonhuman Primate Models for SARS-CoV-2 Research: Cryopreservation as a Means to Maintain Critical Models and Enhance the Genetic Diversity of Colonies
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This commentary, written by ORIP staff, addresses the need for improved cryopreservation methods and resources for nonhuman primate (NHP) gametes and embryos to safeguard newly developed NHP models and enhance the genetic diversity of NHP colonies without reliance on animal importations. Cryopreservation also plays critical roles in medical approaches to preserve the fertility of patients who must undergo potentially gonadotoxic treatments, as well as nascent genome editing efforts to develop new NHP models for human diseases.
Sensitive Tracking of Circulating Viral RNA Through All Stages of SARS-CoV-2 Infection
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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.
Best Practices for Correctly Identifying Coronavirus by Transmission Electron Microscopy
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This paper provides strategies for identifying coronaviruses by transmission electron microscopy in ultrathin sections of tissues or tissue cultures. As illustrated by results in the literature, organ damage may be incorrectly attributed to the presence of virus, since images of coronavirus may resemble subcellular organelles. The paper also references numerous biochemical and imaging techniques to aid an investigator in avoiding pseudo positive identifications. Supported by ORIP (S10OD026776) and others.
The SARS-CoV-2 Receptor and Other Key Components of the Renin-Angiotensin-Aldosterone System Related to COVID-19 are Expressed in Enterocytes in Larval Zebrafish
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Hypertension and respiratory inflammation are exacerbated by the Renin-Angiotensin-Aldosterone System (RAAS), which normally protects from dropping blood pressure via Angiotensin II (Ang II) produced by the enzyme Ace. The Ace paralog Ace2 degrades Ang II and serves as the SARS-CoV-2 receptor. To exploit zebrafish to understand the relationship of RAAS to COVID-19, the group conducted genomic and phylogenetic analyses.
BNT162b Vaccines Protect Rhesus Macaques from SARS-CoV-2
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The preclinical development of two BNT162b vaccine candidates, which contain lipid-nanoparticle formulated nucleoside-modified mRNA encoding SARS-CoV-2 spike glycoprotein-derived immunogens, was performed in rhesus macaques at the Southwest National Primate Research Center (SNPRC). BNT162b1 encodes a soluble, secreted, trimerised receptor-binding domain. BNT162b2 encodes the full-length transmembrane spike glycoprotein, locked in its prefusion conformation.
Modified Vaccinia Ankara Vector-Based Vaccine Protects Macaques from SARS-CoV-2 Infection, Immune Pathology and Dysfunction in the Lung
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Any SARS-CoV-2 vaccine may have limitations such as need for ultracold storage, poor induction of CD8+ T cell response, or lack of cross-reactivity with emerging strains. Thus, multiple vaccines may be needed to bring COVID-19 under control. Using rhesus macaques, researchers showed that a modified vaccinia Ankara (MVA) vector-based SARS-CoV-2 vaccine expressing prefusion-stabilized spike protein induced strong neutralizing antibody and CD8+ T cell responses.