Biology subjects

Cardin, R. D.

Publications and source records attributed to Cardin, R. D..

3 recordsLinked to original sources

bioRxiv2022

Development of a mouse salivary gland-derived mesenchymal cell line for immunological studies of murine cytomegalovirus

The salivary glands are a crucial site of replication for human cytomegalovirus (HCMV) and its murine counterpart, murine cytomegalovirus (MCMV). Studies of MCMV often involve the use of BALB/c strain mice, but most in vitro assays are carried out in the NIH 3T3 cell line, which is derived from Swiss Albino mice. This report describes a BALB/c-derived mouse salivary gland cell line immortalized using the SV40 large T antigen. Cells stained positive for PDGFR1 and negative for E-cadherin and PECAM-1, indicating mesenchymal origin. This cell line, which has been named murine salivary gland mesenchymal (mSGM), shows promise as a tool for ex vivo immunological assays due to its MHC haplotype match with the BALB/c mouse strain. In addition, plaque assays using mSGM rather than NIH 3T3 cells are significantly more sensitive for detecting low concentrations of MCMV particles. Finally, it is demonstrated that mSGM cells express all 3 BALB/c MHC class I isotypes and are susceptible to T cell-mediated ex vivo cytotoxicity assays, leading to many possible uses in immunological studies of MCMV.

microbiology↗

bioRxiv2022

Nirmatrelvir, an orally active Mpro inhibitor, is a potent inhibitor of SARS-CoV-2 Variants of Concern

New variants of SARS-CoV-2 with potential for enhanced transmission, replication, and immune evasion capabilities continue to emerge causing reduced vaccine efficacy and/or treatment failure. As of January 2021, the WHO has defined five variants of concern (VOC): B.1.1.7 (Alpha, ), B.1.351 (Beta, {beta}), P.1 (Gamma, {gamma}), B.1.617.2 (Delta, {delta}), and B.1.1.529 (Omicron, o). To provide a therapeutic option for the treatment of COVID-19 and variants, Nirmatrelvir, the antiviral component of PAXLOVID, an oral outpatient treatment recently authorized for conditional or emergency use treatment of COVID-19, was developed to inhibit SARS-CoV-2 replication. Nirmatrelvir (PF-07321332) is a specific inhibitor of coronavirus main protease (Mpro, also referred to as 3CLpro), with potent antiviral activity against several human coronaviruses, including SARS-CoV-2, SARS-CoV, and MERS (Owen et al, Science 2021. doi: 10.1126/science.abl4784). Here, we evaluated PF-07321332 against the five SARS-CoV-2 VOC (, {beta}, {gamma}, {delta},, o) and two Variants of Interest or VOI, C.37 ({lambda}) and B.1.621 (), using qRT-PCR in VeroE6 cells lacking the P-glycoprotein (Pgp) multidrug transporter gene (VeroE6 P-gp knockout cells). Nirmatrelvir potently inhibited USA-WA1/2020 strain, and , {beta}, {gamma}, {lambda}, {delta}, , and o variants in VeroE6 P-gp knockout cells with mean EC50 values 38.0 nM, 41.0 nM, 127.2 nM, 24.9 nM, 21.2 nM, 15.9 nM, 25.7 nM and 16.2 nM, respectively. Sequence analysis of the Mpro encoded by the variants showed ~100% identity of active site amino acid sequences, reflecting the essential role of Mpro during viral replication leading to ability of Nirmatrelvir to exhibit potent activity across all the variants.

microbiology↗

bioRxiv2022

Nirmatrelvir, Molnupiravir, and Remdesivir maintain potent in vitro activity against the SARS-CoV-2 Omicron variant

Variants of SARS-CoV-2 have become a major public health concern due to increased transmissibility, and escape from natural immunity, vaccine protection, and monoclonal antibody therapeutics. The highly transmissible Omicron variant has up to 32 mutations within the spike protein, many more than previous variants, heightening these concerns of immune escape. There are now multiple antiviral therapeutics that have received approval for emergency use by the FDA and target both the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) and the main protease (Mpro), which have accumulated fewer mutations in known SARS-CoV-2 variants. Here we test nirmatrelvir (PF-07321332), and other clinically relevant SARS-CoV-2 antivirals, against a panel of SARS-CoV-2 variants, including the novel Omicron variant, in live-virus antiviral assays. We confirm that nirmatrelvir and other clinically relevant antivirals all maintain activity against all variants tested, including Omicron.

microbiology↗