J.G.E.Y was the recipient of an Ontario Veterinary College PhD Scholarship and an Ontario Graduate Scholarship. This work was funded by Natural Sciences and Engineering Research Council of Canada Discovery Grants to SKW (grant #304737) and LS (grant #401127).

<ol>
	<li>Kim, S. H., Samal, S. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Newcastle+disease+virus+as+a+vaccine+vector+for+development+of+human+and+veterinary+vaccines.">Newcastle disease virus as a vaccine vector for development of human and veterinary vaccines.</a> Viruses. 8 (7), (2016).</li><li>Kortekaas, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rift+Valley+fever+virus+immunity+provided+by+a+paramyxovirus+vaccine+vector.">Rift Valley fever virus immunity provided by a paramyxovirus vaccine vector.</a> Vaccine. 28 (27), 4394-4401 (2010).</li><li>Matveeva, O. V., Kochneva, G. V., Zainutdinov, S. S., Ilyinskaya, G. V., Chumakov, P. 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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Newcastle+disease+virus+(NDV):+brief+history+of+its+oncolytic+strains.">Newcastle disease virus (NDV): brief history of its oncolytic strains.</a> Journal of Clinical Virology. 16 (1), 1-15 (2000).</li><li>Matuszewska, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+vascular+normalization+with+an+oncolytic+virus+enhances+immunotherapy+in+a+preclinical+model+of+advanced-stage+ovarian+cancer.">Combining vascular normalization with an oncolytic virus enhances immunotherapy in a preclinical model of advanced-stage ovarian cancer.</a> Clinical Cancer Research. 25 (5), 1624-1638 (2019).</li><li>McAusland, T. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+vanadyl+sulfate+with+Newcastle+disease+virus+potentiates+rapid+innate+immune-mediated+regression+with+curative+potential+in+murine+cancer+models.">Combining vanadyl sulfate with Newcastle disease virus potentiates rapid innate immune-mediated regression with curative potential in murine cancer models.</a> Molecular Therapy Oncolytics. 20, 306-324 (2021).</li><li>Warner, B. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intranasal+vaccination+with+a+Newcastle+disease+virus-vectored+vaccine+protects+hamsters+from+SARS-CoV-2+infection+and+disease.">Intranasal vaccination with a Newcastle disease virus-vectored vaccine protects hamsters from SARS-CoV-2 infection and disease.</a> iScience. 24 (11), 103219 (2021).</li><li>Sun, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Newcastle+disease+virus+(NDV)+expressing+the+spike+protein+of+SARS-CoV-2+as+a+live+virus+vaccine+candidate.">Newcastle disease virus (NDV) expressing the spike protein of SARS-CoV-2 as a live virus vaccine candidate.</a> EBioMedicine. 62, (2020).</li><li>Sun, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Newcastle+disease+virus+(NDV)+expressing+a+membrane-anchored+spike+as+a+cost-effective+inactivated+SARS-CoV-2+vaccine.">A Newcastle disease virus (NDV) expressing a membrane-anchored spike as a cost-effective inactivated SARS-CoV-2 vaccine.</a> Vaccines. 8 (4), 1-14 (2020).</li><li>Xu, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+Newcastle+disease+virus+mediated+dendritic+cell+activation+and+cross-priming+tumor-specific+immune+responses+ex+vivo.">Evaluation of Newcastle disease virus mediated dendritic cell activation and cross-priming tumor-specific immune responses ex vivo.</a> International Journal of Cancer. 146 (2), 531-541 (2020).</li><li>Burman, B., Pesci, G., Zamarin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Newcastle+disease+virus+at+the+forefront+of+cancer+immunotherapy.">Newcastle disease virus at the forefront of cancer immunotherapy.</a> Cancers. 12 (12), 1-15 (2020).</li><li>Ricca, J. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pre-existing+immunity+to+oncolytic+virus+potentiates+its+immunotherapeutic+efficacy.">Pre-existing immunity to oncolytic virus potentiates its immunotherapeutic efficacy.</a> Molecular Therapy. 26 (4), 1008-1019 (2018).</li><li>Zamarin, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localized+oncolytic+virotherapy+overcomes+systemic+tumor+resistance+to+immune+checkpoint+blockade+immunotherapy.">Localized oncolytic virotherapy overcomes systemic tumor resistance to immune checkpoint blockade immunotherapy.</a> Science Translational Medicine. 6 (226), (2014).</li><li>Schirrmacher, V., van Gool, S., Stuecker, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breaking+therapy+resistance:+an+update+on+oncolytic+Newcastle+disease+virus+for+improvements+of+cancer+therapy.">Breaking therapy resistance: an update on oncolytic Newcastle disease virus for improvements of cancer therapy.</a> Biomedicines. 7 (3), (2019).</li><li>Santry, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+and+purification+of+high-titer+Newcastle+disease+virus+for+use+in+preclinical+mouse+models+of+cancer.">Production and purification of high-titer Newcastle disease virus for use in preclinical mouse models of cancer.</a> Molecular Therapy Methods and Clinical Development. 9, 181-191 (2018).</li><li>Cassel, W. A., Murray, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+ten-year+follow-up+on+stage+II+malignant+melanoma+patients+treated+postsurgically+with+Newcastle+disease+virus+oncolysate.">A ten-year follow-up on stage II malignant melanoma patients treated postsurgically with Newcastle disease virus oncolysate.</a> Medical Oncology and Tumor Pharmacotherapy. 9 (4), 169-171 (1992).</li><li>Plitt, T., Zamarin, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cancer+therapy+with+Newcastle+disease+virus:+rationale+for+new+immunotherapeutic+combinations.">Cancer therapy with Newcastle disease virus: rationale for new immunotherapeutic combinations.</a> Clinical Investigations. 5 (1), 75-87 (2015).</li><li>Arifin, M. A., Mel, M., Abdul Karim, M. 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U., Morgan, L. A. F., Toms, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+of+human+respiratory+syncytial+virus+by+ultracentrifugation+in+iodixanol+density+gradient.">Purification of human respiratory syncytial virus by ultracentrifugation in iodixanol density gradient.</a> Journal of Virological Methods. 147 (2), 328-332 (2008).</li><li>Zhou, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+rapid+and+efficient+purification+of+Citrus+yellow+vein+clearing+virus+by+sucrose+cushion+ultracentrifugation.">A rapid and efficient purification of Citrus yellow vein clearing virus by sucrose cushion ultracentrifugation.</a> Journal of Plant Pathology. 98 (1), 159-161 (2016).</li><li>Zhao, H., Peeters, B. P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recombinant+Newcastle+disease+virus+as+a+viral+vector:+Effect+of+genomic+location+of+foreign+gene+on+gene+expression+and+virus+replication.">Recombinant Newcastle disease virus as a viral vector: Effect of genomic location of foreign gene on gene expression and virus replication.</a> Journal of General Virology. 84 (4), 781-788 (2003).</li><li>Cheng, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+modification+of+oncolytic+Newcastle+disease+virus+for+cancer+therapy.">Genetic modification of oncolytic Newcastle disease virus for cancer therapy.</a> Journal of Virology. 90 (11), 5343-5352 (2016).</li><li>Chen, T. -. F., Jang, J. -. W., Miller, J. 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The authors have no conflicts of interest to declare.

Viruses used as therapeutic agents in preclinical studies must be highly purified to avoid toxicity when administered in vivo15. If adventitious agents or contaminants are not removed, this can lead to severe adverse reactions negating the therapeutic effect of the viral agent28. As NDV is produced in embryonated chicken eggs, there are several contaminating egg proteins, such as ovalbumin, that must be removed prior to its use in vivo in preclinical or cl...

Newcastle Disease Virus, also known as Avian Orthoavulavirus-1, is an enveloped avian paramyxovirus with the potential to be used both as an oncolytic virus or a viral-vectored vaccine1,2,3,4,5,6,7. Most recently, NDV engineered to express the spike protein of SARS-CoV-2 has been characterized as an effective intranasal vaccine in mouse and hamster challenge models7,8,9. When used as a cancer immunotherapy, it results in the recruitment of innate immune cells, specifically natural killer cells, production of type I interferon, and the generation of antitumor-specific T cells10,11,12,13. In addition to these potent immunostimulatory properties, NDV has a strong safety profile and a well-established reverse genetics system14,15. These desirable characteristics have prompted the evaluation of NDV in numerous preclinical and human clinical trials (NCT04871737, NCT01926028, NCT04764422)16,17. To further advance this highly promising, immune-stimulatory viral vector, detailed methods are needed for producing and purifying high-titer, ultra-pure NDV that can be safely administered in vivo.
As NDV is an avian paramyxovirus, it is most frequently amplified in embryonated chicken eggs. While there are cell-based systems available for propagating NDV, most have been unable to produce titers similar to that achieved in embryonated chicken eggs18. Nevertheless, there are some drawbacks to producing NDV in eggs, including the fact that egg-based production is lengthy and not easily scalable, sourcing large quantities of SPF chicken eggs can be problematic, and there exists the potential for contamination with egg allergens13,18,19,20. Recently, one group has shown that Vero cells grown in suspension in serum-free medium can support the replication of NDV to titers comparable to those achieved in eggs, prior to purification21. However, this required serial passaging of the virus to adapt the virus to Vero cells, and the optimization of a method to purify NDV from suspension Vero cells is still required21.
As highlighted previously, methods used for purifying high-titer, in vivo-grade virus vary depending on the virus in question22. There is a well-established reverse genetics system available for the generation of recombinant NDV. This process, involving the use of a cDNA clone, helper plasmids, and a helper virus expressing T7 RNA polymerase, has been previously described in detail15,23. This protocol can be applied to either lentogenic or mesogenic NDV. The virus described in this protocol is a recombinant mesogenic NDV encoding the green fluorescent protein (GFP) from the jellyfish Aequorea victoria inserted between viral P and M genes as an individual transcription unit, as this has previously been described as the optimal site for foreign transgene insertion24.
Enclosed methods outline the purification of NDV based on its size, ranging from 100 to 500 nm, and its density15. This has allowed for the generation of in vivo-grade, high-titer NDV stocks in approximately 3 weeks, starting from when the eggs are received to having a final titer. Techniques frequently used in the large-scale production of egg-based viruses such as tangential flow filtration, depth filtration, and density gradient ultracentrifugation are described, enabling the translation of these methods to larger-scale production. Previously described techniques for the purification of NDV have been improved by the incorporation of a virus-stabilizing buffer, use of iodixanol during density gradient ultracentrifugation, and the description of various quality control measures to ensure in vivo-grade quality15. This has allowed for the purification of in vivo-grade NDV reaching titers as high as 3 &#215; 1010 PFU/mL from 0.8 to 1.0 L of allantoic fluid.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.25% Trypsin</td>
			<td>HyClone</td>
			<td>SH30042.02</td>
			<td></td>
		</tr>
		<tr>
			<td>1 mL Slip-Tip Syringe</td>
			<td>BD</td>
			<td>309659</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mL Luer-Lok Syringe</td>
			<td>BD</td>
			<td>302995</td>
			<td></td>
		</tr>
		<tr>
			<td>10% Povidone Iodine Solution</td>
			<td>LORIS</td>
			<td>109-08</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL Conical Tubes</td>
			<td>Thermo-Fisher</td>
			<td>14955240</td>
			<td></td>
		</tr>
		<tr>
			<td>18G x 1 1/2 in Blunt Fill Needle</td>
			<td>BD</td>
			<td>305180</td>
			<td></td>
		</tr>
		<tr>
			<td>18G x 1 1/2 in Precision Glide Needle</td>
			<td>BD</td>
			<td>305196</td>
			<td></td>
		</tr>
		<tr>
			<td>25 G x 5/8 in Needle</td>
			<td>BD</td>
			<td>305122</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Thermo-Fisher</td>
			<td>03446I-100</td>
			<td></td>
		</tr>
		<tr>
			<td>30% Acrylamide/Bis Solution 37.5:1</td>
			<td>BioRad</td>
			<td>1610158</td>
			<td></td>
		</tr>
		<tr>
			<td>4% Paraformaldehyde-PBS</td>
			<td>Thermo-Fisher</td>
			<td>J19943-K2</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL Luer-Lok Syringe</td>
			<td>BD</td>
			<td>309646</td>
			<td></td>
		</tr>
		<tr>
			<td>96 Well Tissue Culture Plate - Flat Bottom</td>
			<td>Greiner Bio One</td>
			<td>655180</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic Acid, Glacial</td>
			<td>Thermo-Fisher</td>
			<td>A38-212</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Froggabio</td>
			<td>A87-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>Alexa-Fluor 488 Goat-Anti-Mouse</td>
			<td>Invitrogen</td>
			<td>A11001</td>
			<td></td>
		</tr>
		<tr>
			<td>Allegra X-14 Centrifuge</td>
			<td>Beckman Coulter</td>
			<td>B08861</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium Persulfate</td>
			<td>BioRad</td>
			<td>161-0700</td>
			<td></td>
		</tr>
		<tr>
			<td>Bleach (5%)</td>
			<td>Thermo-Fisher</td>
			<td>36-102-0599</td>
			<td></td>
		</tr>
		<tr>
			<td>Broad, unserrated tipped forceps</td>
			<td>Thermo-Fisher</td>
			<td>09-753-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Bromophenol Blue</td>
			<td>Sigma-Aldrich</td>
			<td>114405-25G</td>
			<td></td>
		</tr>
		<tr>
			<td>Centramate Cassette Holder</td>
			<td>PALL</td>
			<td>CM018V</td>
			<td></td>
		</tr>
		<tr>
			<td>ChemiDoc XRS+</td>
			<td>BioRad</td>
			<td>1708265</td>
			<td></td>
		</tr>
		<tr>
			<td>CO2 Incubator</td>
			<td>Thermo-Fisher</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Coomassie Brilliant Blue R-259</td>
			<td>Thermo-Fisher</td>
			<td>BP101-50</td>
			<td></td>
		</tr>
		<tr>
			<td>DF1 Cells</td>
			<td>ATCC</td>
			<td>CRL-12203</td>
			<td></td>
		</tr>
		<tr>
			<td>Diet Gel Recovery</td>
			<td>ClearH2O, INC</td>
			<td>72-01-1062</td>
			<td></td>
		</tr>
		<tr>
			<td>Digital 1502 Sportsman Egg Incubator</td>
			<td>Berry Hill</td>
			<td>1502W</td>
			<td></td>
		</tr>
		<tr>
			<td>D-Mannitol</td>
			<td>Sigma-Aldrich</td>
			<td>M4125-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>Egg Candler</td>
			<td>Berry Hill</td>
			<td>A46</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol (70%)</td>
			<td>Thermo-Fisher</td>
			<td>BP82031GAL</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethylenediaminetetraacetic acid (EDTA) solution, pH 8.0, 0.5 M in H2O</td>
			<td>Thermo-Fisher</td>
			<td>BP2482-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Female Threaded Tee fittings, nylon, 1/8 in NPT(F)</td>
			<td>Cole-Parmer</td>
			<td>06349-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Gibco</td>
			<td>12483-020</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine Point High Precision Forceps</td>
			<td>Thermo-Fisher</td>
			<td>22-327379</td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescent Microscope</td>
			<td>ZEISS AXIO</td>
			<td></td>
			<td>Not necessary if not performing IFA or if NDV does not encode a fluorescent protein</td>
		</tr>
		<tr>
			<td>Freeze Dry System Freezone 4.5</td>
			<td>LABCONCO</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>GiBOX Gel Imager</td>
			<td>Syngene</td>
			<td></td>
			<td>Imaging of Agarose Gels</td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Thermo-Fisher</td>
			<td>G33-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>Thermo-Fisher</td>
			<td>BP381-5</td>
			<td></td>
		</tr>
		<tr>
			<td>High Capacity cDNA Reverse Transcriptase Kit</td>
			<td>Thermo-Fisher</td>
			<td>4368814</td>
			<td></td>
		</tr>
		<tr>
			<td>High Glucose Dulbecco&#39;s Modified Essential Medium</td>
			<td>Cytiva</td>
			<td>SH30022.01</td>
			<td></td>
		</tr>
		<tr>
			<td>Humidity Kit</td>
			<td>Berry Hill</td>
			<td>3030</td>
			<td></td>
		</tr>
		<tr>
			<td>Iodixanol</td>
			<td>Sigma-Aldrich</td>
			<td>D1556</td>
			<td>60% (w/v) solution of iodixanol in water (sterile)</td>
		</tr>
		<tr>
			<td>L-Lysine Monohydrochloride</td>
			<td>Sigma-Aldrich</td>
			<td>62929-100G-F</td>
			<td></td>
		</tr>
		<tr>
			<td>Male and Female Luer-Lok a 1/8 in national pipe thread, NPT</td>
			<td>Cole-Parmer</td>
			<td>41507-44</td>
			<td></td>
		</tr>
		<tr>
			<td>Masterflex L/S Digital Drive</td>
			<td>Cole-Parmer</td>
			<td>RK-07522-20</td>
			<td>Peristaltic Pump with digital display</td>
		</tr>
		<tr>
			<td>Masterflex L/S Easy Load Pump Head for Precision Tubing</td>
			<td>Cole-Parmer</td>
			<td>RK-07514-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Masterflex Silicon tubing (Platinum) L/S 16</td>
			<td>Cole-Parmer</td>
			<td>96420-16</td>
			<td>BioPharm Platinum-Cured Silicone</td>
		</tr>
		<tr>
			<td>MC Pro 5 Thermocycler</td>
			<td>Eppendorf</td>
			<td>EP950040025</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Thermo-Fisher</td>
			<td>A412-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Mini Protean Tetra Cell</td>
			<td>BioRad</td>
			<td>1658000EDU</td>
			<td>SDS-PAGE cast and running appartus</td>
		</tr>
		<tr>
			<td>Mouse-Anti-NDV</td>
			<td>Novus Biologicals</td>
			<td>NBP2-11633</td>
			<td>Clone 6H12</td>
		</tr>
		<tr>
			<td>Normal Goat Serum</td>
			<td>Abcam</td>
			<td>AB7481</td>
			<td></td>
		</tr>
		<tr>
			<td>NP-40</td>
			<td>Thermo-Fisher</td>
			<td>85124</td>
			<td></td>
		</tr>
		<tr>
			<td>Omega Membrane LV Centramate Cassette, 100K</td>
			<td>PALL</td>
			<td>OS100T02</td>
			<td></td>
		</tr>
		<tr>
			<td>Optima XE-90 Ultracentrifuge</td>
			<td>Beckman Coulter</td>
			<td>A94471</td>
			<td></td>
		</tr>
		<tr>
			<td>OWL Easycast B1A Mini Gel Electrophoresis System</td>
			<td>Thermo-Fisher</td>
			<td>B1A</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS 10X Solution</td>
			<td>Thermo-Fisher</td>
			<td>BP399-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly(Ethylene Glycol) Average Mn 20,000</td>
			<td>Sigma-Aldrich</td>
			<td>81300-1KG</td>
			<td></td>
		</tr>
		<tr>
			<td>PowePac 300</td>
			<td>BioRad</td>
			<td></td>
			<td>Model 1655050 - for Agarose gel electrophoresis</td>
		</tr>
		<tr>
			<td>Q5 High Fidelity 2X Master Mix</td>
			<td>New England Biolabs</td>
			<td>M0492S</td>
			<td></td>
		</tr>
		<tr>
			<td>QIA Amp Viral RNA Mini Kit</td>
			<td>Qiagen</td>
			<td>52904</td>
			<td></td>
		</tr>
		<tr>
			<td>RedSafe</td>
			<td>Thermo-Fisher</td>
			<td>50999562</td>
			<td></td>
		</tr>
		<tr>
			<td>Slide-a-lyzer Dialysis Cassette (Extra Strength), 10,000 MWCO 0.5-3 mL</td>
			<td>Thermo-Fisher</td>
			<td>66380</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Dodecyl Sulfate</td>
			<td>Thermo-Fisher</td>
			<td>BP166-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Hydroxide (Pellets)</td>
			<td>Thermo-Fisher</td>
			<td>S318-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Specific pathogen free eggs</td>
			<td>CFIA</td>
			<td>NA</td>
			<td>Supplier will vary depending on location</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Thermo-Fisher</td>
			<td>S5-3</td>
			<td></td>
		</tr>
		<tr>
			<td>Supracap 50 Depth Filter</td>
			<td>PALL</td>
			<td>SC050V100P</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical Scissors</td>
			<td>Thermo-Fisher</td>
			<td>08-951-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Sw41Ti Rotor</td>
			<td>Beckman Coulter</td>
			<td>331362</td>
			<td>Used in protocol step 2.3.1, 2.3.6, 2.3.7</td>
		</tr>
		<tr>
			<td>SX4750 Rotor</td>
			<td>Beckman Coulter</td>
			<td>369702</td>
			<td></td>
		</tr>
		<tr>
			<td>SxX4750 Adaptor for Concial-Bottom Tubes</td>
			<td>Beckman Coulter</td>
			<td>359472</td>
			<td></td>
		</tr>
		<tr>
			<td>TEMED</td>
			<td>Invitrogen</td>
			<td>15524-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Thin-Wall Ultraclear centrifuge tubes (9/16 in x 3 1/2 in)</td>
			<td>Beckman Coulter</td>
			<td>344059</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris Base</td>
			<td>Thermo-Fisher</td>
			<td>BP152-5</td>
			<td></td>
		</tr>
		<tr>
			<td>Tubing Screw Clamp</td>
			<td>PALL</td>
			<td>88216</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Sigma-Aldrich</td>
			<td>P1379-1L</td>
			<td></td>
		</tr>
		<tr>
			<td>Utility Pressure Gauges</td>
			<td>Cole-Parmer</td>
			<td>68355-06</td>
			<td></td>
		</tr>
	</tbody>
</table>

production of high-titer recombinant newcastle disease virus from allantoic fluid

Newcastle disease virus (NDV), also known as avian orthoavulavirus serotype-1, is a negative sense, single-stranded RNA virus that has been developed both as an oncolytic virus and a viral-vectored vaccine. NDV is an attractive therapeutic and prophylactic agent due to its well-established reverse genetics system, potent immunostimulatory properties, and excellent safety profile. When administered as an oncolytic virus or a viral-vectored vaccine, NDV elicits a robust antitumor or antigen-specific immune response, activating both the innate and adaptive arms of the immune system. 
Given these desirable characteristics, NDV has been evaluated in numerous clinical trials and is one of the most well-studied oncolytic viruses. Currently, there are two registered clinical trials involving NDV: one evaluating a recombinant NDV-vectored vaccine for SARS-CoV-2 (NCT04871737), and a second evaluating a recombinant NDV encoding Interleukin-12 in combination with Durvalumab, an antiPD-L1 antibody (NCT04613492). To facilitate further advancement of this highly promising viral vector, simplified methods for generating high-titer, in vivo-grade, recombinant NDV (rNDV) are needed. 
This paper describes a detailed procedure for amplifying rNDV in specified pathogen-free (SPF) embryonated chicken eggs and purifying rNDV from allantoic fluid, with improvements to reduce loss during purification. Also included are descriptions of the recommended quality control assays, which should be performed to confirm lack of contaminants and virus integrity. Overall, this detailed procedure enables the synthesis, purification, and storage of high-titer, in vivo-grade, recombinant, lentogenic, and mesogenic NDV for use in preclinical studies.

Harvesting allantoic fluid 
As allantoic fluid is harvested from embryonated chicken eggs, it should appear clear and transparent. If the fluid appears opaque and yellow, this indicates the presence of contaminants. Inclusion of this allantoic fluid during purification will impede the purification process, as the pressure will quickly rise and surpass 10 psi, resulting in the shearing of the virus and loss of infectious virus. Allantoic fluid that appears bloody suggests that the eggs were inoculate...

Watch this Scientific Journal Video about Production of High-Titer Recombinant Newcastle Disease Virus from Allantoic Fluid at JoVE.com

Production of High-Titer Recombinant Newcastle Disease Virus from Allantoic Fluid

Here we provide a detailed procedure for production, purification, and quantification of high-titer recombinant Newcastle disease virus. This protocol consistently yields &#62; 6 &#215; 109 plaque-forming units/mL, providing virus quantities appropriate for in vivo animal studies. Additional quality control assays to ensure safety in vivo are described.

Newcastle disease virus (NDV), also known as avian orthoavulavirus serotype-1, is a negative sense, single-stranded RNA virus that has been developed both ...

production-high-titer-recombinant-newcastle-disease-virus-from

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JoVE Journal

Cancer Research

3.4K Views.  University of Guelph. Here we provide a detailed procedure for production, purification, and quantification of high-titer recombinant Newcastle disease virus. This protocol consistently yields > 6 × 109 plaque-forming units/mL, providing virus quantities appropriate for in vivo animal studies. Additional quality control assays to ensure safety in vivo are described.

Video: Production of High-Titer Recombinant Newcastle Disease Virus from Allantoic Fluid

Virus Delivery of CRISPR Guides to the Murine Prostate for Gene Alteration

With an increasing incidence of prostate cancer, identification of new tumor drivers or modulators is crucial. Genetically engineered mouse models (GEMM) for prostate cancer are hampered by tumor heterogeneity and its complex microevolution dynamics. Traditional prostate cancer mouse models include, amongst others, germline and conditional knockouts, transgenic expression of oncogenes, and xenograft models. Generation of de novo mutations in these models is complex, time-consuming, and costly. In addition, most of traditional models target the majority of the prostate epithelium, whereas human prostate cancer is well known to evolve as an isolated event in only a small subset of cells. Valuable models need to simulate not only prostate cancer initiation, but also progression to advanced disease.
Here we describe a method to target a few cells in the prostate epithelium by transducing cells by viral particles. The delivery of an engineered virus to the murine prostate allows alteration of gene expression in the prostate epithelia. Virus type and quantity will hereby define the number of targeted cells for gene alteration by transducing a few cells for cancer initiation and many cells for gene therapy. Through surgery-based injection in the anterior lobe, distal from the urinary track, the tumor in this model can expand without impairing the urinary function of the animal. Furthermore, by targeting only a subset of prostate epithelial cells the technique enables clonal expansion of the tumor, and therefore mimics human tumor initiation, progression, as well as invasion through the basal membrane.
This novel technique provides a powerful prostate cancer model with improved physiological relevance. Animal suffering is limited, and since no additional breeding is required, overall animal count is reduced. At the same time, analysis of new candidate genes and pathways is accelerated, which in turn is more cost efficient.

This protocol describes a newly established method for virus delivery to the murine prostate. Using either CRISPR/Cas9 technology, gene overexpression, or Cre recombinase delivery, the technique allows orthotopic alteration of gene expression and implements a novel mouse model for prostate cancer.

With an increasing incidence of prostate cancer, identification of new tumor drivers or modulators is crucial. Genetically engineered mouse models (GEMM) ...

Methods for Evaluating the Role of c-Fos and Dusp1 in Oncogene Dependence

The demonstration of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) has heralded a new era in cancer therapeutics. However, a small population of cells does not respond to TKI treatment, resulting in minimal residual disease (MRD); even the most potent TKIs fail to eradicate these cells. These MRD cells serve as a reservoir to develop resistance to therapy. Why TKI treatment is ineffective against MRD cells is not known. Growth factor signaling is implicated in supporting the survival of MRD cells during TKI treatment, but a mechanistic understanding is lacking. Recent studies demonstrated that an elevated c-Fos and Dusp1 expression as a result of convergent oncogenic and growth factor signaling in MRD cells mediate TKI resistance. The genetic and chemical inhibition of c-Fos and Dusp1 renders CML exquisitely sensitive to TKIs and cures CML in both genetic and humanized mouse models. We identified these target genes using multiple microarrays from TKI-sensitive and -resistant cells. Here, we provide methods for target validation using in vitro and in vivo mouse models. These methods can easily be applied to any target for genetic validation and therapeutic development.

Here, we describe protocols for the genetic and chemical validation of c-Fos and Dusp1 as a drug target in leukemia using in vitro and in vivo genetic and humanized mouse models. This method can be applied to any target for genetic validation and therapeutic development.

The demonstration of tyrosine kinase inhibitors (TKIs) in treating chronic myeloid leukemia (CML) has heralded a new era in cancer therapeutics. However, ...

Neutrophil Extracellular Traps Generated by Low Density Neutrophils Obtained from Peritoneal Lavage Fluid Mediate Tumor Cell Growth and Attachment

Activated neutrophils release neutrophil extracellular traps (NETs), which can capture and destroy microbes. Recent studies suggest that NETs are involved in various disease processes, such as autoimmune disease, thrombosis, and tumor metastases. Here, we show a detailed in vitro technique to detect NET activity during the trapping of free tumor cells, which grow after attachment to NETs. First, we collected low density neutrophils (LDN) from postoperative peritoneal lavage fluid from patients who underwent laparotomies. Short-term culturing of LDN resulted in massive NET formation that was visualized with green fluorescent nuclear and chromosome counterstain. After co-incubation of human gastric cancer cell lines MKN45, OCUM-1, and NUGC-4 with the NETs, many tumor cells were trapped by the NETs. Subsequently, the attachment was completely abrogated by the degradation of NETs with DNase I. Time-lapse video revealed that tumor cells trapped by the NETs did not die but instead grew vigorously in a continuous culture. These methods may be applied to the detection of adhesive interactions between NETs and various types of cells and materials.

Here, we present a method in which human low-density neutrophils (LDN), recovered from postoperative peritoneal lavage fluid, produce massive neutrophil extracellular traps (NETs) and efficiently trap free tumor cells that subsequently grow.

Activated neutrophils release neutrophil extracellular traps (NETs), which can capture and destroy microbes. Recent studies suggest that NETs are involved ...

A Simple Migration/Invasion Workflow Using an Automated Live-cell Imager

Cancer cell mobility is crucial for the initiation of metastasis. Therefore, investigation of the cell movement and invasive capacity is of great significance. Migration assays provide basic insight of cell movement at a 2D level, whereas invasion assays are more physiologically relevant, mimicking in vivo cancer cell dislodgment from the original site and invading through the extracellular matrix. The current protocol provides a single workflow for migration and invasion assays. Together with the integrated automated microscopic camera for real-time HD images and built-in analysis module, it gives researchers a time-efficient, simple and reproducible experimental option. This protocol also includes substitutions for the consumables and alternative analysis methods for users to choose from.

The current protocol describes an integrated method investigating cancer cell migration and invasion on a single platform in real-time, providing an easily reproducible and time-efficient option to study cell mobility and morphology.

Cancer cell mobility is crucial for the initiation of metastasis. Therefore, investigation of the cell movement and invasive capacity is of great ...

Evaluating Cell Death Using Cell-Free Supernatant of Probiotics in Three-Dimensional Spheroid Cultures of Colorectal Cancer Cells

This manuscript describes a protocol to evaluate cancer cell deaths in three dimensional (3D) spheroids of multicellular types of cancer cells using supernatants from Lactobacillus fermentum cell culture, considered as probiotics cultures. The use of 3D cultures to test Lactobacillus cell-free supernatant (LCFS) are a better option than testing in 2D monolayers, especially as L. fermentum can produce anti-cancer effects within the gut. L. fermentum supernatant was identified to possess increased anti-proliferative effects against several colorectal cancer (CRC) cells in 3D culture conditions. Interestingly, these effects were strongly related to the culture model, demonstrating the notable ability of L. fermentum to induce cancer cell death. Stable spheroids were generated from diverse CRCs (colorectal cancer cells) using the protocol presented below. This protocol of generating 3D spheroid is time saving and cost effective. This system was developed to easily investigate the anti-cancer effects of LCFS in multiple types of CRC spheroids. As expected, CRC spheroids treated with LCFS strongly induced cell death during the experiment and expressed specific apoptosis molecular markers as analyzed by qRT-PCR, western blotting, and FACS analysis. Therefore, this method is valuable for exploring cell viability and evaluating the efficacy of anti-cancer drugs.

Here methods are presented to understand anti-cancer effects of Lactobacillus cell-free supernatant (LCFS). Colorectal cancer cell lines show cell deaths when treated with LCFS in 3D cultures. The process of generating spheroids can be optimized depending on the scaffold and the analysis methods presented are useful for evaluating the involved signaling pathways.

This manuscript describes a protocol to evaluate cancer cell deaths in three dimensional (3D) spheroids of multicellular types of cancer cells using ...

A Murine Ommaya Xenograft Model to Study Direct-Targeted Therapy of Leptomeningeal Disease

Leptomeningeal disease (LMD) is an uncommon type of central nervous system (CNS) metastasis to the cerebral spinal fluid (CSF). The most common cancers that cause LMD are breast and lung cancers and melanoma. Patients diagnosed with LMD have a very poor prognosis and generally survive for only a few weeks or months. One possible reason for the lack of efficacy of systemic therapy against LMD is the failure to achieve therapeutically effective concentrations of drug in the CSF because of an intact and relatively impermeable blood-brain barrier (BBB) or blood-CSF barrier across the choroid plexus. Therefore, directly administering drugs intrathecally or intraventricularly may overcome these barriers. This group has developed a model that allows for the effective delivery of therapeutics (i.e., drugs, antibodies, and cellular therapies) chronically and the repeated sampling of CSF to determine drug concentrations and target modulation in the CSF (when the tumor microenvironment is targeted in mice). The model is the murine equivalent of a magnetic resonance imaging-compatible Ommaya reservoir, which is used clinically. This model, which is affixed to the skull, has been designated as the &#34;Murine Ommaya.&#34; As a therapeutic proof of concept, human epidermal growth factor receptor 2 antibodies (clone 7.16.4) were delivered into the CSF via the Murine Ommaya to treat mice with LMD from human epidermal growth factor receptor 2-positive breast cancer. The Murine Ommaya increases the efficiency of drug delivery using a miniature access port and prevents the wastage of excess drug; it does not interfere with CSF sampling for molecular and immunological studies. The Murine Ommaya is useful for testing novel therapeutics in experimental models of LMD.

Here, we describe a murine xenograft model that functionally resembles an Ommaya reservoir in patients. We developed the Murine Ommaya to study novel therapeutics for the universally fatal leptomeningeal disease.

Leptomeningeal disease (LMD) is an uncommon type of central nervous system (CNS) metastasis to the cerebral spinal fluid (CSF). The most common cancers ...

Portal Vein Injection of Colorectal Cancer Organoids to Study the Liver Metastasis Stroma

Hepatic metastasis of colorectal cancer (CRC) is a leading cause of cancer-related death. Cancer-associated fibroblasts (CAFs), a major component of the tumor microenvironment, play a crucial role in metastatic CRC progression and predict poor patient prognosis. However, there is a lack of satisfactory mouse models to study the crosstalk between metastatic cancer cells and CAFs. Here, we present a method to investigate how liver metastasis progression is regulated by the metastatic niche and possibly could be restrained by stroma-directed therapy. Portal vein injection of CRC organoids generated a desmoplastic reaction, which faithfully recapitulated the fibroblast-rich histology of human CRC liver metastases. This model was tissue-specific with a higher tumor burden in the liver when compared to an intra-splenic injection model, simplifying mouse survival analyses. By injecting luciferase-expressing tumor organoids, tumor growth kinetics could be monitored by in vivo imaging. Moreover, this preclinical model provides a useful platform to assess the efficacy of therapeutics targeting the tumor mesenchyme. We describe methods to examine whether adeno-associated virus-mediated delivery of a tumor-inhibiting stromal gene to hepatocytes could remodel the tumor microenvironment and improve mouse survival. This approach enables the development and assessment of novel therapeutic strategies to inhibit hepatic metastasis of CRC.

Portal vein injection of colorectal cancer (CRC) organoids generates stroma-rich liver metastasis. This mouse model of CRC hepatic metastasis represents a useful tool to study tumor-stroma interactions and develop novel stroma-directed therapeutics such as adeno-associated virus-mediated gene therapies.

Hepatic metastasis of colorectal cancer (CRC) is a leading cause of cancer-related death. Cancer-associated fibroblasts (CAFs), a major component of the ...

A Three-Dimensional Spheroid Model to Investigate the Tumor-Stromal Interaction in Hepatocellular Carcinoma

The aggressiveness and lack of well-tolerated and widely effective treatments for advanced hepatocellular carcinoma (HCC), the predominant form of liver cancer, rationalize its rank as the second most common cause of cancer-related death. Preclinical models need to be adapted to recapitulate the human conditions to select the best therapeutic candidates for clinical development and aid the delivery of personalized medicine. Three-dimensional (3D) cellular spheroid models show promise as an emerging in vitro alternative to two-dimensional (2D) monolayer cultures. Here, we describe a 3D tumor spheroid&#160;model which exploits the ability of individual cells to aggregate when maintained in hanging droplets, and is more representative of an in vivo environment than standard monolayers. Furthermore, 3D spheroids can be produced by combining homotypic or heterotypic cells, more reflective of the cellular heterogeneity in vivo, potentially enabling the study of environmental interactions that can influence progression and treatment responses. The current research optimized the cell density to form 3D homotypic and heterotypic tumor spheroids by immobilizing cell suspensions on the lids of standard 10 cm3 Petri dishes. Longitudinal analysis was performed to generate growth curves for homotypic versus heterotypic tumor/fibroblasts spheroids. Finally, the proliferative impact of fibroblasts (COS7 cells) and liver myofibroblasts (LX2) on homotypic tumor (Hep3B) spheroids was investigated. A seeding density of 3,000 cells (in 20 &#181;L media) successfully yielded Huh7/COS7 heterotypic spheroids, which displayed a steady increase in size up to culture day 8, followed by growth retardation. This finding was corroborated using Hep3B homotypic spheroids cultured in LX2 (human hepatic stellate cell line) conditioned medium (CM). LX2 CM triggered the proliferation of Hep3B spheroids compared to control tumor spheroids. In conclusion, this protocol has shown that 3D tumor spheroids can be used as a simple, economical, and prescreen in vitro tool to study tumor-stromal interactions more comprehensively.

Comprehensive in vitro models that faithfully recapitulate the relevant human disease are lacking. The current study presents three-dimensional (3D) tumor spheroid creation and culture, a reliable in vitro tool to study the tumor-stromal interaction in human hepatocellular carcinoma.

The aggressiveness and lack of well-tolerated and widely effective treatments for advanced hepatocellular carcinoma (HCC), the predominant form of liver ...

High-Resolution Ultrasonography for the Analysis of Orthotopic ATC Tumors in a Genetically Engineered Mouse Model

Anaplastic thyroid carcinoma (ATC) is associated with a poor prognosis and short median survival time, but no effective treatment improves the outcomes significantly. Genetically engineered murine models that mimic ATC&#39;s progression may help researchers to study treatments for this disease. Crossing three different genotypes of mice, a TPO-cre/ERT2; BrafCA/wt; Trp53&#916;ex2-10/&#916;ex2-10&#160;transgenic ATC model was developed. The ATC murine model was induced by an intraperitoneal injection of tamoxifen with overexpression of BrafV600E and deletion of Trp53, and the tumors were generated within about 1 month. High-resolution ultrasound was applied to investigate the tumor initiation and progression, and the dynamic growth curve was obtained by measuring the tumor sizes. Compared to magnetic resonance imaging (MRI) and computed tomography scanning, ultrasound has advantages in observing the ATC murine model, such as being noninvasive, portable, in real-time, and without radiation exposure. High-resolution ultrasound is suitable for dynamic and multiple measurements. However, ultrasonographic examination of the thyroid in mice requires relevant anatomical knowledge and experience. This article provides a detailed procedure for utilizing high-resolution ultrasound to scan tumors in the transgenic ATC model. Meanwhile, ultrasonic parameter adjustment, ultrasound scanning skills, anesthesia and recovery of the animals, and other elements that need attention during the process are listed.

The present protocol describes high-frequency ultrasonography for visualizing the entire mouse thyroid gland and monitoring the growth of anaplastic thyroid carcinoma.

Anaplastic thyroid carcinoma (ATC) is associated with a poor prognosis and short median survival time, but no effective treatment improves the outcomes ...

Murine Model for Studying Leptomeningeal Disease Using Circulating Tumor Cells

Ex Vivo Culture of Circulating Tumor Cells in the Cerebral Spinal Fluid from Melanoma Patients to Study Melanoma&#45;Associated Leptomeningeal Disease

Melanoma-associated leptomeningeal disease (M-LMD) occurs when circulating tumor cells (CTCs) enter into the cerebral spinal fluid (CSF) and colonize the meninges, the membrane layers that protect the brain and the spinal cord. Once established, the prognosis for M-LMD patients is dismal, with overall survival ranging from weeks to months. This is primarily due to a paucity in our understanding of the disease and, as a consequence, the availability of effective treatment options. Defining the underlying biology of M-LMD will significantly improve the ability to adapt available therapies for M-LMD treatment or design novel inhibitors for this universally fatal disease. A major barrier, however, lies in obtaining sufficient quantities of CTCs from the patient-derived CSF (CSF-CTCs) to conduct preclinical experiments, such as molecular characterization, functional analysis, and in vivo efficacy studies. Culturing CSF-CTCs ex vivo has also proven to be challenging. To address this, a novel protocol for the culture of patient-derived M-LMD CSF-CTCs ex vivo and in vivo is developed. The incorporation of conditioned media produced by human meningeal cells (HMCs) is found to be critical to the procedure. Cytokine array analysis reveals that factors produced by HMCs, such as insulin-like growth factor-binding proteins (IGFBPs) and vascular endothelial growth factor-A (VEGF-A), are important in supporting CSF-CTC survival ex vivo. Here, the usefulness of the isolated patient-derived CSF-CTC lines is demonstrated in determining the efficacy of inhibitors that target the insulin-like growth factor (IGF) and mitogen-activated protein kinase (MAPK) signaling pathways. In addition, the ability to intrathecally inoculate these cells in vivo to establish murine models of M-LMD that can be employed for preclinical testing of approved or novel therapies is shown. These tools can help unravel the underlying biology driving CSF-CTC establishment in the meninges and identify novel therapies to reduce the morbidity and mortality associated with M-LMD.

Author Spotlight: Assessing the Potential of Circulating Tumor Cells in Leptomeningeal Disease Research

This article describes a protocol for the propagation of cerebral spinal fluid-circulating tumor cells (CSF-CTCs) collected from patients with melanoma-associated leptomeningeal disease (M-LMD) to develop preclinical models to study M-LMD.

Melanoma-associated leptomeningeal disease (M-LMD) occurs when circulating tumor cells (CTCs) enter into the cerebral spinal fluid (CSF) and colonize the ...