scholarly journals Optimized Protocols for the Propagation and Quantification of Infectious Murine Hepatitis Virus (MHV-A59) Using NCTC Clone 1469 and 929 Cells

2022 ◽  
Vol 5 (1) ◽  
pp. 5
Author(s):  
Tautvydas Shuipys ◽  
Naim Montazeri

Murine hepatitis virus (MHV) is a non-human pathogen betacoronavirus that is evolutionarily and structurally related to the human pathogenic viruses SARS-CoV, MERS-CoV, and SARS-CoV-2. However, unlike the human SARS and MERS viruses, MHV requires a biosafety level 2 laboratory for propagating and safe handling, making it a potentially suitable surrogate virus. Despite this utility, few papers discussed the propagation and quantification of MHV using cell lines readily available in biorepositories making their implementations not easily reproducible. This article provides protocols for propagating and quantifying MHV-A59 using the recommended NCTC clone 1469 and clone 929 cell lines from American Type Culture Collection (ATCC). More specifically, the methods detail reviving cells, routine cell passaging, preparing freeze stocks, infection of NCTC clone 1469 with MHV and subsequent harvesting, and plaque assay quantification of MHV using NCTC clone 929 cells. Using these protocols, a BSL-2 laboratory equipped for cell culture work would generate at least 6.0 log plaque-forming units (PFU) per mL of MHV lysate and provide an optimized overlay assay using either methylcellulose or agarose as overlays for the titration of infectious virus particles. The protocols described here are intended to be utilized for persistence and inactivation studies of coronaviruses.

2021 ◽  
Author(s):  
Austin Blake Featherstone ◽  
Sapna Chitlapilly Dass

Meat processing plants have been at the center of the SARS-CoV-2 pandemic. There are several factors that contribute to the persistence of SARS-CoV-2 in meat processing plants and one of the factors is the formation of a multi-species biofilm with virus. Biofilm can act as a reservoir in protecting, harboring, and dispersing SARS-CoV-2 from biofilm to the meat processing facility environment. We used Murine Hepatitis Virus (MHV) as a surrogate for SARS-CoV-2 virus and meat processing facility drain samples to develop mixed-species biofilms on commonly found materials in processing facilities (Stainless-Steel (SS), PVC and tiles). The results showed that MHV was able to integrate into the environmental biofilm and survived for a period of 5 days at 7C. There was no significate difference between the viral-environmental biofilm biovolumes developed on different materials SS, PVC, and tiles. There was a 2-fold increase in the virus-environmental biofilm biovolume when compared to environmental biofilm by itself. These results indicate a complex virus-environmental biofilm interaction which is providing enhanced protection for the survival of viral particles with the environmental biofilm community.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Rui Yu ◽  
Yunyun Mao ◽  
Kai Li ◽  
Yanfang Zhai ◽  
Yue Zhang ◽  
...  

Coronaviruses (CoVs) are enveloped and harbor an unusually large (30–32 kb) positive-strand linear RNA genome. Highly pathogenic coronaviruses cause severe acute respiratory syndrome (SARS) (SARS-CoV and SARS-CoV-2) and Middle East respiratory syndrome (MERS) (MERS-CoV) in humans. The coronavirus mouse hepatitis virus (MHV) infects mice and serves as an ideal model of viral pathogenesis, mainly because experiments can be conducted using animal-biosafety level-2 (A-BSL2) containment. Human thymosin beta-4 (Tβ4), a 43-residue peptide with an acetylated N-terminus, is widely expressed in human tissues. Tβ4 regulates actin polymerization and functions as an anti-inflammatory molecule and an antioxidant as well as a promoter of wound healing and angiogenesis. These activities led us to test whether Tβ4 serves to treat coronavirus infections of humans. To test this possibility, here, we established a BALB/c mouse model of coronavirus infection using mouse CoV MHV-A59 to evaluate the potential protective effect of recombinant human Tβ4 (rhTβ4). Such a system can be employed under A-BSL2 containment instead of A-BSL3 that is required to study coronaviruses infectious for humans. We found that rhTβ4 significantly increased the survival rate of mice infected with MHV-A59 through inhibiting virus replication, balancing the host’s immune response, alleviating pathological damage, and promoting repair of the liver. These results will serve as the basis for further application of rhTβ4 to the treatment of human CoV diseases such as COVID-19.


Author(s):  
B. G. Uzman ◽  
M. M. Kasac ◽  
H. Saito ◽  
A. Krishan

In conjunction with the cultivation and transplantation of cells from human tumors by the Programs of Microbiology and Immunogenetics, virus surveillance by electron microscopy has been routinely employed. Of particular interest in this regard have been 3 cell lines cultured from lymph nodes or spleen of 2 patients with Hodgkin's disease and 1 patient with Letterer-Siwe's disease. Each of these cell lines when transplanted in Syrian hamster neonates conditioned with anti-lymphocyte serum grew as serially transplantable tumors; from such transplants of the 3 cell lines cell cultures were retrieved.Herpes type virus particles (Figs. 1, 2, 3) were found in the primary cultures of all three lines, in frozen thawed aliquots of same, and in cultures retrieved from their tumors growing by serial transplantation in hamsters. No virus was detected in sections of 25 of the serially transplanted tumors. However, in 10 such tumors there were repeated instances of tubular arrays in the cisternae of the endoplasmic reticulum (Fig. 4). On serologic examination the herpes virus was shown to be the Epstein-Barr virus.


2021 ◽  
Vol 9 (2) ◽  
pp. 307
Author(s):  
Evelyn J. Franco ◽  
Xun Tao ◽  
Kaley C. Hanrahan ◽  
Jieqiang Zhou ◽  
Jürgen B. Bulitta ◽  
...  

Chikungunya virus (CHIKV) is an alphavirus associated with a broad tissue tropism for which no antivirals or vaccines are approved. This study evaluated the antiviral potential of favipiravir (FAV), interferon-alpha (IFN), and ribavirin (RBV) against CHIKV as mono- and combination-therapy in cell lines that are clinically relevant to human infection. Cells derived from human connective tissue (HT-1080), neurons (SK-N-MC), and skin (HFF-1) were infected with CHIKV and treated with different concentrations of FAV, IFN, or RBV. Viral supernatant was sampled daily and the burden was quantified by plaque assay on Vero cells. FAV and IFN were the most effective against CHIKV on various cell lines, suppressing the viral burden at clinically achievable concentrations; although the degree of antiviral activity was heavily influenced by cell type. RBV was not effective and demonstrated substantial toxicity, indicating that it is not a feasible candidate for CHIKV. The combination of FAV and IFN was then assessed on all cell lines. Combination therapy enhanced antiviral activity in HT-1080 and SK-N-MC cells, but not in HFF-1 cells. We developed a pharmacokinetic/pharmacodynamic model that described the viral burden and inhibitory antiviral effect. Simulations from this model predicted clinically relevant concentrations of FAV plus IFN completely suppressed CHIKV replication in HT-1080 cells, and considerably slowed down the rate of viral replication in SK-N-MC cells. The model predicted substantial inhibition of viral replication by clinical IFN regimens in HFF-1 cells. Our results highlight the antiviral potential of FAV and IFN combination regimens against CHIKV in clinically relevant cell types.


Virology ◽  
1984 ◽  
Vol 137 (2) ◽  
pp. 297-304 ◽  
Author(s):  
Dennis P. Jackson ◽  
Dean H. Percy ◽  
Vincent L. Morris

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adrian Creanga ◽  
Rebecca A. Gillespie ◽  
Brian E. Fisher ◽  
Sarah F. Andrews ◽  
Julia Lederhofer ◽  
...  

AbstractBroadly neutralizing antibodies (bnAbs) have been developed as potential countermeasures for seasonal and pandemic influenza. Deep characterization of these bnAbs and polyclonal sera provides pivotal understanding for influenza immunity and informs effective vaccine design. However, conventional virus neutralization assays require high-containment laboratories and are difficult to standardize and roboticize. Here, we build a panel of engineered influenza viruses carrying a reporter gene to replace an essential viral gene, and develop an assay using the panel for in-depth profiling of neutralizing antibodies. Replication of these viruses is restricted to cells expressing the missing viral gene, allowing it to be manipulated in a biosafety level 2 environment. We generate the neutralization profile of 24 bnAbs using a 55-virus panel encompassing the near-complete diversity of human H1N1 and H3N2, as well as pandemic subtype viruses. Our system offers in-depth profiling of influenza immunity, including the antibodies against the hemagglutinin stem, a major target of universal influenza vaccines.


1965 ◽  
Vol 24 (1) ◽  
pp. 57-78 ◽  
Author(s):  
J. F. David-Ferreira ◽  
R. A. Manaker

Samples taken at different intervals of time from suspension cultures of the NCTC 1469 line of mouse liver—derived (ML) cells infected with a mouse hepatitis virus have been studied with the electron microscope. The experiments revealed that the viruses are incorporated into the cells by viropexis within 1 hour after being added to the culture. An increasing number of particles are found later inside dense cytoplasmic corpuscles similar to lysosomes. In the cytoplasm of the cells from the samples taken 7 hours after inoculation, two organized structures generally associated and never seen in the controls are observed: one consists of dense material arranged in a reticular disposition (reticular inclusion); the other is formed by small tubules organized in a complex pattern (tubular body). No evidence has been found concerning their origin. Their significance is discussed. With the progression of the infection a system of membrane-bounded tubules and cisternae is differentiated in the cytoplasm of the ML cells. In the lumen of these tubules or cisternae, which are occupied by a dense material, numerous virus particles are observed. The virus particles which originate in association with the limiting membranes of tubules and cisternae are released into their lumen by a "budding" process. The virus particles are 75 mµ in diameter and possess a nucleoid constituted of dense particles or rods limiting an electron transparent core. The virus limiting membrane is sometimes covered by an outer layer of a dense material. In the cells from the samples taken 14 to 20 hours after inoculation, larger zones of the cell cytoplasm are occupied by inclusion bodies formed by channels or cisternae with their lumens containing numerous virus particles. In the samples taken 20 hours or more after the inoculation numerous cells show evident signs of degeneration.


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