In vitro Polio virus inhibition by two guanidino-pyrimidines

AbstractThe SARS-CoV-2 virus responsible for the COVID-19 pandemic has so far infected more than 100 million people globally, and continues to undergo genomic evolution. Emerging SARS-CoV-2 variants show increased infectivity and may lead to resistance against immune responses of previously immunized individuals or existing therapeutics, especially antibody-based therapies.Several monoclonal antibody therapeutics authorized for emergency use or in development start to lose potency against various SARS-CoV-2 variants. Cocktails of two different monoclonal antibodies constitute a promising approach to protect against such variants as long as both antibodies are potent, but come with increased development complexity and therefore cost. As an alternative, we developed two multi-specific DARPin® therapeutics, each combining three independent DARPin® domains binding the SARS-CoV-2 spike protein in one molecule, to potently neutralize the virus and overcome virus escape.Here, we show in a panel of in vitro studies that both multi-specific DARPin® therapeutics, ensovibep (MP0420) and MP0423, are highly potent against the new circulating SARS-CoV-2 variants B.1.1.7 (UK variant) and B.1.351 (South African variant) and the most frequent emerging mutations in the spike protein. Additionally, viral passaging experiments show potent protection by ensovibep and MP0423 against development of escape mutations. Furthermore, we demonstrate that the cooperative binding of the individual modules in a multi-specific DARPin® antiviral is key for potent virus inhibition and protection from escape variants. These results, combined with the relatively small size and high production yields of DARPin® molecules, suggests ensovibep and MP0423 as superior alternatives to monoclonal antibody cocktails for global supply and demonstrate the strength of the DARPin® platform for achieving potent and lasting virus inhibition for SARS-CoV-2 and possibly other viruses.

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L-Asparaginase from the BCG Strain of Mycobacterium bovis. I. Purification and In Vitro Immunosuppressive Properties

Canadian Journal of Biochemistry ◽

10.1139/o72-157 ◽

1972 ◽

Vol 50 (11) ◽

pp. 1149-1157 ◽

Cited By ~ 11

Author(s):

Eugenia Soru ◽

M. Teodorescu ◽

Odette Zaharia ◽

Judith Szabados ◽

Karin Rudescu

Keyword(s):

Spleen Cell ◽

Mycobacterium Bovis ◽

Cell Cultures ◽

Cell Transformation ◽

Polyacrylamide Gel Electrophoresis ◽

Gel Filtration ◽

Blast Cell ◽

Polio Virus ◽

Negative Adsorption

L-Asparaginase isolated from the BCG strain of Mycobacterium bovis has been purified approximately 100-fold by negative adsorption on Ca-phosphate gel, batchwise adsorption and column chromatography on DEAE-Sephadex, gel filtration through Bio Gel P-200, and crystallization.The final enzyme preparation appeared to be pure on the basis of cellulose acetate and polyacrylamide gel electrophoresis, immunodiffusion, and immunoelectrophoresis in agar gel.Inhibition by crystalline BCG L-asparaginase of blast cell transformation was demonstrated by means of thymidine-3H incorporation in phytohemagglutinin-stimulated rabbit spleen cell cultures. This effect was not observed with heat-inactivated enzyme.Antibody synthesis in spleen cell cultures which were secondarily stimulated in vitro with polio virus was also depressed.Intradermal inoculation of crystalline BCG L-asparaginase in BCG-sensitized guinea pigs gave no significant tuberculin type reaction.

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Feline parvovirus propagates in cat bone marrow cultures and inhibits hematopoietic colony formation in vitro

Blood ◽

10.1182/blood.v74.1.71.71 ◽

1989 ◽

Vol 74 (1) ◽

pp. 71-81 ◽

Cited By ~ 15

Author(s):

GJ Kurtzman ◽

L Platanias ◽

L Lustig ◽

N Frickhofen ◽

NS Young

Keyword(s):

Bone Marrow ◽

Colony Formation ◽

Neutralizing Antibodies ◽

Gm Csf ◽

Virus Inhibition ◽

Myeloid Progenitor Cells ◽

Bone Marrow Cultures ◽

Infected Cells ◽

Feline Parvovirus

Abstract Feline parvovirus (FPV) causes leukopenia in naturally infected cats. We investigated the mechanism of hematopoietic depression by this virus in feline bone marrow cultured in vitro. In suspension cultures we demonstrated FPV propagation and replication using DNA molecular hybridization. Viral RNA and DNA were observed by in situ hybridization in about 10% of marrow cells at day 3. Granulocytes and their precursors were virtually absent from infected cultures after six days. Infected cells showed viral capsid protein predominantly in nuclei by immunofluorescence. In clonal assays, FPV most efficiently inhibited hematopoietic colony formation by myeloid progenitor cells (CFU-GM), but erythroid colony formation (BFU-E and CFU-E-derived) was also depressed in the presence of virus. Inhibition of colony formation could be abrogated by physical inactivation of the virus or preincubation with specific neutralizing antibodies. Recombinant human colony stimulating factors GM-CSF and G-CSF supported feline myelopoiesis in progenitor assays, and FPV completely inhibited factor dependent colony formation.

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Rubella Virus: Inhibition in vitro by Amantadine Hydrochloride

Science ◽

10.1126/science.145.3639.1443 ◽

1964 ◽

Vol 145 (3639) ◽

pp. 1443-1444 ◽

Cited By ~ 41

Author(s):

H. F. Maassab ◽

K. W. Cochran

Keyword(s):

Rubella Virus ◽

Virus Inhibition

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In-vitro Evaluation of Antiviral Activity of Moringa oleifera Extracts against Polio virus

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2020/v32i2430815 ◽

2020 ◽

pp. 101-109

Author(s):

Halidu Mhya Adamu ◽

Mahmud Yerima Iliyasu ◽

Mohammed Nuru Yakubu ◽

Adamu Babayo Samaila ◽

Ahmed Faruk Umar

Keyword(s):

Antiviral Activity ◽

Moringa Oleifera ◽

Virus Stock ◽

Polio Virus ◽

Plant Parts ◽

Laboratory Techniques ◽

The University ◽

Virus Isolates ◽

Virus Strains

Background: Moringa oleifera plant parts extract have been utilized tremendously in traditional medicine, having various pharmaceutical activities such as antifungal, antibacterial and antiviral properties. Aim: This study was carried out to evaluate antiviral activity of aqueous extract of Moringa leaves, seeds and flowers against Polio virus isolates (Vaccine Strains P1&P3), MDG-17-04852; MDG-17-04881. Study Design: This is a baseline study carried out to determine the efficacy of Moringa oleifera in the treatment of poliomyelitis. Place and Duration of Study: This study was carried out at the University of Maiduguri Teaching Hospital Maiduguri and Abubakar Tafawa Balewa University, Bauchi from September 2018 to October, 2019. Methods: Phytochemical substances was extracted and screened from the Moringa using standard laboratory techniques. Continuous cell line L20B cells was used to isolate polio virus. Polio virus stock was prepared and titration was carried out to determine TCID50 by Kerber’s formula, L-d(S - 0.5). Cytotoxicity of the extracts was evaluated using the end-point cytopathic effect assay. Antiviral assay and Polio virus Intratypic Differentiation (ITD) was performed using Real-Time PCR. Results: The results revealed present of Tannins in leaves and flowers, Alkaloids and Saponins in all the extracts, Glycosides and Steroids in leaves and Flavonoids in flowers only. Cytotoxicity of the extracts shows 50% effects in 100mg and 50mg concentrations, while 33.3% and 16.7% was observed in 25mg and 12.5mg (P>.05). The titration of the tissue culture infective dose 50% (TCID50) shows that Polio virus type 1and 3 had a titre value of 106.5 and 106.25 respectively. The ITD results observed presence of Sl1 and Sl3 from the extracts. Conclusion: This study found that the Moringa extracts did not neutralized the Polio virus strains studied, as the phytochemicals show no antiviral activity. Therefore further study is needed in this area to ascertain its antiviral potentials against poliomyelitis.

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Feline parvovirus propagates in cat bone marrow cultures and inhibits hematopoietic colony formation in vitro

Blood ◽

10.1182/blood.v74.1.71.bloodjournal74171 ◽

1989 ◽

Vol 74 (1) ◽

pp. 71-81

Author(s):

GJ Kurtzman ◽

L Platanias ◽

L Lustig ◽

N Frickhofen ◽

NS Young

Keyword(s):

Bone Marrow ◽

Colony Formation ◽

Neutralizing Antibodies ◽

Gm Csf ◽

Virus Inhibition ◽

Myeloid Progenitor Cells ◽

Bone Marrow Cultures ◽

Infected Cells ◽

Feline Parvovirus

Feline parvovirus (FPV) causes leukopenia in naturally infected cats. We investigated the mechanism of hematopoietic depression by this virus in feline bone marrow cultured in vitro. In suspension cultures we demonstrated FPV propagation and replication using DNA molecular hybridization. Viral RNA and DNA were observed by in situ hybridization in about 10% of marrow cells at day 3. Granulocytes and their precursors were virtually absent from infected cultures after six days. Infected cells showed viral capsid protein predominantly in nuclei by immunofluorescence. In clonal assays, FPV most efficiently inhibited hematopoietic colony formation by myeloid progenitor cells (CFU-GM), but erythroid colony formation (BFU-E and CFU-E-derived) was also depressed in the presence of virus. Inhibition of colony formation could be abrogated by physical inactivation of the virus or preincubation with specific neutralizing antibodies. Recombinant human colony stimulating factors GM-CSF and G-CSF supported feline myelopoiesis in progenitor assays, and FPV completely inhibited factor dependent colony formation.

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Reliable Estimation of CD8 T Cell Inhibition of In Vitro HIV-1 Replication

Frontiers in Immunology ◽

10.3389/fimmu.2021.666991 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yinyan Xu ◽

Ann Marie Weideman ◽

Maria Abad-Fernandez ◽

Katie R. Mollan ◽

Sallay Kallon ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Cd8 T Cell ◽

People Living With Hiv ◽

Viral Inhibition ◽

Hiv Replication ◽

Virus Inhibition ◽

Hiv 1

The HIV-1 viral inhibition assay (VIA) measures CD8 T cell-mediated inhibition of HIV replication in CD4 T cells and is increasingly used for clinical testing of HIV vaccines and immunotherapies. The VIA has multiple sources of variability arising from in vitro HIV infection and co-culture of two T cell populations. Here, we describe multiple modifications to a 7-day VIA protocol, the most impactful being the introduction of independent replicate cultures for both HIV infected-CD4 (HIV-CD4) and HIV-CD4:CD8 T cell cultures. Virus inhibition was quantified using a ratio of weighted averages of p24+ cells in replicate cultures and the corresponding 95% confidence interval. An Excel template is provided to facilitate calculations. Virus inhibition was higher in people living with HIV suppressed on antiretroviral therapy (n=14, mean: 40.0%, median: 43.8%, range: 8.2 to 73.3%; p < 0.0001, two-tailed, exact Mann-Whitney test) compared to HIV-seronegative donors (n = 21, mean: -13.7%, median: -14.4%, range: -49.9 to 20.9%) and was stable over time (n = 6, mean %COV 9.4%, range 0.9 to 17.3%). Cross-sectional data were used to define 8% inhibition as the threshold to confidently detect specific CD8 T cell activity and determine the minimum number of culture replicates and p24+ cells needed to have 90% statistical power to detect this threshold. Last, we note that, in HIV seronegative donors, the addition of CD8 T cells to HIV infected CD4 T cells consistently increased HIV replication, though the level of increase varied markedly between donors. This co-culture effect may contribute to the weak correlations observed between CD8 T cell VIA and other measures of HIV-specific CD8 T cell function.

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Phyto-fabricated Cr2O3 nanoparticle for multifunctional biomedical applications

Nanomedicine ◽

10.2217/nnm-2020-0129 ◽

2020 ◽

Vol 15 (17) ◽

pp. 1653-1669

Author(s):

Hamza Elsayed Ahmed Mohamed ◽

Shakeeb Afridi ◽

Ali Talha Khalil ◽

Tanzeel Zohra ◽

Muhammad Ali ◽

...

Keyword(s):

Biological Properties ◽

In Vitro Assays ◽

X Ray Diffraction ◽

Potential Measurement ◽

Polio Virus ◽

X Ray ◽

Selected Area Electron Diffraction ◽

Transmission Electron ◽

Vis Spectroscopy

Aim: The biosynthesis of chromium oxide nanoparticles (Cr2O3 NPs), using Hyphaene thebaica as a bioreductant, for assessment of their potential nanomedicinal applications. Materials & methods: Biosynthesized Cr2O3 NPs were characterized by x-ray diffraction, Fourier-transform infrared spectroscopy, energy dispersive x-ray spectroscopy, scanning and transmission electron microscopy, selected area electron diffraction, UV–Vis spectroscopy and ζ-potential measurement. In vitro assays were used to assess the biological properties of Cr2O3 NPs. Results: Nanoparticles with size approximately 25–38 nm were obtained with a characteristic Cr–O vibration at 417 cm-1. A broad spectrum antimicrobial potential and antioxidant nature is reported. Slight inhibition of polio virus and biocompatibility at low doses was observed. Conclusion: We conclude a multifunctional nature of biogenic Cr2O3 NPs.

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Antiviral Activity and Mode of Action Studies of Ribavirin and Mycophenolic Acid against Orthopoxviruses in Vitro

Antiviral Chemistry and Chemotherapy ◽

10.1177/095632020101200602 ◽

2001 ◽

Vol 12 (6) ◽

pp. 327-335 ◽

Cited By ~ 52

Author(s):

Donald F Smee ◽

Mike Bray ◽

John W Huggins

Keyword(s):

Mycophenolic Acid ◽

Mode Of Action ◽

Inosine Monophosphate Dehydrogenase ◽

3T3 Cells ◽

African Green Monkey Kidney ◽

Cell Monolayers ◽

Virus Inhibition ◽

Vaccinia Viruses ◽

Complete Reversal

Two inhibitors of cellular inosine monophosphate dehydrogenase, mycophenolic acid (MPA) and ribavirin, were evaluated for inhibitory activity against orthopoxviruses. Unrelated antipoxvirus agents tested for comparison included 6-azauridine, cidofovir (HPMPC) and cyclic HPMPC. MPA inhibited camelpox, cowpox, monkeypox and vaccinia viruses by 50% in plaque reduction assays at 0.2–3 μM in African green monkey kidney (Vero 76) and mouse 3T3 cells. Ribavirin was considerably more active in 3T3 cells (50% inhibition at 2-l2 μM) than in Vero 76 cells (inhibitory at 30–250 μM) against these viruses. In cytotoxicity assays, MPA and ribavirin were more toxic to replicating cells than to stationary cell monolayers, with greater toxicity seen in 3T3 than in Vero 76 cells. The superior antiviral potency and increased toxicity of ribavirin in 3T3 cells was related to greater accumulation of mono-, di- and triphosphate forms of the drug compared with Vero 76 cells. For both MPA and ribavirin, virus inhibition was closely correlated to the extent of suppression of intracellular guanosine triphosphate (GTP) pools. Treatment with extracellular guanosine (which restored intracellular GTP levels) did not lead to complete reversal of the anticowpox virus activity of ribavirin. This suggests that other modes of virus inhibition also appear to contribute to the anti-orthopoxvirus activity of ribavirin. Biological differences in mode of action and immunosuppressive potential between ribavirin and MPA may account for why the former compound is active against orthopoxvirus infections in animals and the latter inhibitor is not.

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