These methods were established in the Virotherapy Group led by Prof. Dr.&#160;Dr. Guy Ungerechts at the National Center for Tumor Diseases in Heidelberg. We are indebted to him and all members of the laboratory team, especially Dr. Tobias Speck, Dr. R&#363;ta Veinalde, Judith F&#246;rster, Birgit Hoyler, and Jessica Albert. This work was supported by the Else Kr&#246;ner-Fresenius-Stiftung (Grant 2015_A78 to C.E. Engeland) and the German National Science Foundation (DFG, grant EN 1119/2-1 to C.E. Engeland). J.P.W. Heidbuechel receives a stipend by the Helmholtz International Graduate School for Cancer Research.

NOTE: [O], [P], and [M] indicate subsections applicable to: OVs in general, (most) paramyxoviruses, or MV only, respectively. [B] indicates sections specific for BTE transgenes.
1 Cloning of Immunomodulator-encoding Transgenes into Measles Virus Vectors
<ol>
	<li>[O] Design insert sequence.
	<ol>
		<li>[O] Decide on an immunomodulator of interest based on literature research or on exploratory data such as genetic screens41 and derive ...

Oncolytic immunotherapy (i.e., OVT in combination with immunomodulation) holds great promise for cancer treatment, demanding further development and optimization of oncolytic viruses encoding immunomodulatory proteins. This protocol describes methods to generate and validate such vectors for subsequent testing in relevant preclinical models and potential future clinical translation into novel anti-cancer therapeutics.
Numerous different oncolytic virus platforms with distinct advantag...

Oncolytic viruses (OVs) are being developed as anti-cancer therapeutics that specifically replicate within and kill tumor cells while leaving healthy tissues intact. It has now become common understanding that oncolytic virotherapy (OVT), in most cases, does not rely solely on complete tumor lysis by efficient replication and spreading of the virus, but requires additional mechanisms of action for treatment success, including vascular and stromal targeting and, importantly, immune stimulation1,2,3,4. While many early OV studies used&#160;unmodified viruses, current research has profited from an improved biological understanding, virus biobanks that potentially contain novel OVs, and the possibilities offered by genetic engineering in order to create advanced OV platforms5,6,7.
Given the recent success of immunotherapy, immunomodulatory transgenes are of particular interest regarding the genetic engineering of OVs. Targeted expression of such gene products by OV-infected tumor cells reduces toxicity compared to systemic administration. Targeting is achieved either by using viruses with inherent oncoselectivity or by modifying viral tropism8. Local immunomodulation enhances the multi-faceted anti-tumor mechanisms of OVT. Furthermore, this strategy is instrumental in interrogating the interplay between viruses, tumor cells, and the host immune system. To this end, this protocol provides an applicable and adjustable workflow to design, clone, rescue, propagate, and validate oncolytic paramyxovirus (specifically measles virus) vectors encoding such transgenes.
Modulation of the immune response can be achieved by a wide variety of transgene products targeting different steps of the cancer-immunity cycle9, including enhancing tumor antigen recognition [e.g., tumor-associated antigens (TAAs) or inducers of major histocompatibility complex (MHC) class I molecules] over supporting dendritic cell maturation for efficient antigen presentation (cytokines); recruiting and activating desired immune cells such as cytotoxic and helper T cells [chemokines, bispecific T cell engagers (BTEs)]; targeting suppressive cells such as regulatory T cells, myeloid-derived suppressor cells, tumor-associated macrophages, and cancer-associated fibroblasts (antibodies, BTEs, cytokines); and preventing effector cell inhibition and exhaustion (checkpoint inhibitors). Thus, a plethora of biological agents is available. Evaluation of such virus-encoded immunomodulators regarding therapeutic efficacy and possible synergies as well as understanding of respective mechanisms is necessary to improve&#160;cancer therapy.
Negative sense single-stranded RNA viruses of the Paramyxoviridae family are characterized by several features conducive to their use as oncolytic vectors. These include a natural oncotropism, large genomic capacity for transgenes (more than 5 kb)10,11, efficient spreading including syncytia formation, and high immunogenicity12. Therefore, OV platforms based on canine distemper virus13, mumps virus14, Newcastle disease virus15, Sendai virus16,17, simian virus 518, and Tupaia paramyxovirus19 have been developed. Most prominently, live attenuated measles virus vaccine strains (MV) have progressed in preclinical and clinical development20,21. These virus strains have been used for decades for routine immunization with an excellent safety record22. Moreover, there is no risk for insertional mutagenesis due to the strictly cytosolic replication of paramyxoviruses. A versatile reverse genetics system based on anti-genomic cDNA which allows for insertion of transgenes into additional transcription units (ATUs) is available11,23,24. MV vectors encoding sodium-iodide symporter (MV-NIS) for imaging and radiotherapy or soluble carcinoembryonic antigen (MV-CEA) as a surrogate marker for viral gene expression are currently being evaluated in clinical trials (NCT02962167, NCT02068794, NCT02192775, NCT01846091, NCT02364713, NCT00450814, NCT02700230, NCT03456908, NCT00408590, and NCT00408590). Safe administration has been confirmed and cases of anti-tumor efficacy have been reported in previous studies25,26,27,28,29,30 (reviewed by Msaouel et al.31), paving the way for additional oncolytic measles viruses that have been developed and tested preclinically. MV encoding immunomodulatory molecules targeting diverse steps of the cancer-immunity cycle have been shown to delay tumor growth and/or prolong survival in mice, with evidence for immune-mediated efficacy and long-term protective immune memory in syngeneic mouse models. Vector-encoded transgenes include granulocyte-macrophage colony stimulating factor (GM-CSF)32,33, H. pylori neutrophil-activating protein34, immune checkpoint inhibitors35, interleukin-12 (IL-12)36, TAAs37, and BTEs38, which cross-link a tumor surface antigen with CD3 and thus induce anti-tumor activity by polyclonal T cells, irrespective of T cell receptor specificity and co-stimulation (Figure 1). The promising preclinical results obtained for these constructs demand further translational efforts.
Talimogene laherparepvec (T-VEC), a type I herpes simplex virus encoding GM-CSF, is the only oncolytic therapeutic approved by the United States Food and Drug Administration (FDA) and European Medicines Agency (EMA). The phase III study leading to approvals in late 2015 has not only shown efficacy at the site of intra-tumoral injection, but also&#160;abscopal effects (i.e., remissions of non-injected lesions) in advanced melanoma39. T-VEC has since entered additional trials for application in other tumor entities (e.g., non-melanoma skin cancer, NCT03458117; pancreatic cancer, NCT03086642) and for evaluation of combination therapies, especially with immune checkpoint inhibitors (NCT02978625, NCT03256344, NCT02509507, NCT02263508, NCT02965716, NCT02626000, NCT03069378, NCT01740297, and Ribas et al.40).
This demonstrates not only the potential of oncolytic immunotherapy but also the need for further research to identify superior combinations of OVT and immunomodulation. Rational design of additional vectors and their development for preclinical testing is key to this undertaking. This will also advance understanding of underlying mechanisms and has implications for the progression towards more personalized cancer treatment. To this end, this publication presents the methodology for the modification and development of paramyxoviruses for targeted cancer immunotherapy and, more specifically, of oncolytic measles viruses encoding T cell-engaging antibodies (Figure 2).

<table border="0" cellpadding="0" cellspacing="0" style="width:833px;" width="833">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Rapid DNA Dephos &#38; Ligation Kit</td>
			<td style="width:312px;">Roche Life Science, Mannheim, Germany</td>
			<td style="width:123px;">4898117001</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">CloneJET PCR Cloning Kit</td>
			<td style="width:312px;">Thermo Fisher Scientific, St. Leon-Rot</td>
			<td style="width:123px;">K1231</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Agarose</td>
			<td style="width:312px;">Sigma-Aldrich, Taufkirchen, Germany</td>
			<td style="width:123px;">A9539-500G</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">QIAquick Gel Extraction Kit</td>
			<td style="width:312px;">QIAGEN, Hilden, Germany</td>
			<td style="width:123px;">28704</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:244px;">NEB 10-beta Competent E. coli</td>
			<td style="width:312px;">New England Biolabs (NEB), Frankfurt/Main, Germany</td>
			<td style="width:123px;">C3019I</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">LB medium after Lennox</td>
			<td style="width:312px;">Carl Roth, Karlsruhe, Germany</td>
			<td style="width:123px;">X964.1</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Ampicillin</td>
			<td style="width:312px;">Carl Roth, Karlsruhe, Germany</td>
			<td style="width:123px;">HP62.1</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">QIAquick Miniprep Kit</td>
			<td style="width:312px;">QIAGEN, Hilden, Germany</td>
			<td style="width:123px;">27104</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:244px;">Restriction enzyme HindIII-HF</td>
			<td style="width:312px;">New England Biolabs (NEB), Frankfurt/Main, Germany</td>
			<td style="width:123px;">R3104S</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:244px;">Dulbecco&#39;s Modified Eagle&#39;s Medium (DMEM)</td>
			<td style="width:312px;">Invitrogen, Darmstadt, Germany</td>
			<td style="width:123px;">31966-021</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Fetal bovine serum (FBS)</td>
			<td style="width:312px;">Biosera, Boussens, France</td>
			<td style="width:123px;">FB-1280/500</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:244px;">FugeneHD</td>
			<td style="width:312px;">Promega, Mannheim, Germany</td>
			<td style="width:123px;">E2311</td>
			<td style="width:155px;">may be replaced by transfection reagent of choice</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Kanamycin</td>
			<td style="width:312px;">Sigma-Aldrich, Taufkirchen, Germany</td>
			<td style="width:123px;">K0129</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Vero cells</td>
			<td style="width:312px;">ATCC, Manassas, VA, USA</td>
			<td style="width:123px;">CCL81</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">B16-CD46/ B16-CD20-CD46</td>
			<td style="width:312px;">J. Heidbuechel, DKFZ Heidelberg</td>
			<td style="width:123px;"></td>
			<td style="width:155px;">available upon request</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Granta-519</td>
			<td style="width:312px;">DSMZ, Braunschweig, Germany</td>
			<td style="width:123px;">ACC 342</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Opti-MEM (serum-free medium)</td>
			<td style="width:312px;">Gibco Life Technologies, Darmstadt, Germany</td>
			<td style="width:123px;">31985070</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Colorimetric Cell Viability Kit III (XTT)</td>
			<td style="width:312px;">PromoKine, Heidelberg, Germany</td>
			<td style="width:123px;">PK-CA20-300-1000</td>
			<td style="width:155px;">includes XTT reagent</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:244px;">Dulbecco&#39;s Phosphate-Buffered Saline (PBS)</td>
			<td style="width:312px;">Gibco Life Technologies, Darmstadt, Germany</td>
			<td style="width:123px;">14190-094</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">QIAquick Ni-NTA Spin Columns</td>
			<td style="width:312px;">QIAGEN, Hilden, Germany</td>
			<td style="width:123px;">31014</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Sodium chloride</td>
			<td style="width:312px;">Carl Roth, Karlsruhe, Germany</td>
			<td style="width:123px;">3957.3</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Imidazole</td>
			<td style="width:312px;">Carl Roth, Karlsruhe, Germany</td>
			<td style="width:123px;">I5513-25G</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:244px;">Amicon Ultra-15, PLGC Ultracel-PL Membran, 10&#160;kDa</td>
			<td style="width:312px;">Merck, Darmstadt, Germany</td>
			<td style="width:123px;">UFC901024</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">BCA Protein Assay Kit</td>
			<td style="width:312px;">Merck Milipore</td>
			<td style="width:123px;">71285-3</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">IgG from human serum</td>
			<td style="width:312px;">Sigma-Aldrich, Taufkirchen, Germany</td>
			<td style="width:123px;">I4506</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Anti-HA-PE</td>
			<td style="width:312px;">Miltenyi Biotech, Bergisch Gladbach, Germany</td>
			<td style="width:123px;">130-092-257</td>
			<td style="width:155px;">RRID: AB_871939</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:244px;">Mouse IgG1, kappa Isotype Control, Phycoerythrin Conjugated, Clone MOPC-21 antibody</td>
			<td style="width:312px;">BD Biosciences, Heidelberg, Germany</td>
			<td style="width:123px;">555749</td>
			<td style="width:155px;">RRID: AB_396091</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Anti-HA-biotin antibody, clone 3F10</td>
			<td style="width:312px;">Sigma-Aldrich, Taufkirchen, Germany</td>
			<td style="width:123px;">12158167001</td>
			<td style="width:155px;">RRID: AB_390915</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Anti-Biotin MicroBeads</td>
			<td style="width:312px;">Miltenyi Biotech, Bergisch Gladbach, Germany</td>
			<td style="width:123px;">130-090-485</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">MS Columns</td>
			<td style="width:312px;">Miltenyi Biotech, Bergisch Gladbach, Germany</td>
			<td style="width:123px;">130-042-201</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">MiniMACS Separator</td>
			<td style="width:312px;">Miltenyi Biotech, Bergisch Gladbach, Germany</td>
			<td style="width:123px;">130-042-102</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">MACS MultiStand</td>
			<td style="width:312px;">Miltenyi Biotech, Bergisch Gladbach, Germany</td>
			<td style="width:123px;">130-042-303</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:244px;">RIPA buffer</td>
			<td style="width:312px;">Rockland Immunochemicals, Gilbertsville, PA, USA</td>
			<td style="width:123px;">MB-030-0050</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:244px;">CytoTox 96 Non-Radioactive Cytotoxicity Assay</td>
			<td style="width:312px;">Promega, Mannheim, Germany</td>
			<td style="width:123px;">G1780</td>
			<td style="width:155px;">includes 10x lysis solution, substrate solution (substrate mix and assay buffer), and stop solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">Cell lifter</td>
			<td style="width:312px;">Corning, Reynosa, Mexico</td>
			<td style="width:123px;">3008</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">10 cm dishes</td>
			<td style="width:312px;">Corning, Oneonta, NY, USA</td>
			<td style="width:123px;">430167</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">15 cm dishes</td>
			<td style="width:312px;">Greiner Bio-One, Frickenhausen, Germany</td>
			<td style="width:123px;">639160</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">96-well plates, U-bottom</td>
			<td style="width:312px;">TPP, Trasadingen, Switzerland</td>
			<td style="width:123px;">92097</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">96-well plates, flat bottom</td>
			<td style="width:312px;">Neolab, Heidelberg, Germany</td>
			<td style="width:123px;">353072</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">6-well plates</td>
			<td style="width:312px;">Neolab, Heidelberg, Germany</td>
			<td style="width:123px;">353046</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">12-well plates</td>
			<td style="width:312px;">Neolab, Heidelberg, Germany</td>
			<td style="width:123px;">353043</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">50 mL tubes</td>
			<td style="width:312px;">nerbe plus, Winsen/Luhe, Germany</td>
			<td style="width:123px;">02-572-3001</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">T175 cell culture flasks</td>
			<td style="width:312px;">Thermo Fisher Scientific, St. Leon-Rot</td>
			<td style="width:123px;">159910</td>
			<td style="width:155px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:244px;">0.22 &#181;m filters</td>
			<td style="width:312px;">Merck, Darmstadt, Germany</td>
			<td style="width:123px;">SLGPM33RS</td>
			<td style="width:155px;"></td>
		</tr>
	</tbody>
</table>

paramyxoviruses for tumor-targeted immunomodulation: design and evaluation ex vivo

Successful cancer immunotherapy has the potential to achieve long-term tumor control. Despite recent clinical successes, there remains an urgent need for safe and effective therapies tailored to individual tumor immune profiles. Oncolytic viruses enable the induction of anti-tumor immune responses as well as tumor-restricted gene expression. This protocol describes the generation and ex vivo analysis of immunomodulatory oncolytic vectors. Focusing on measles vaccine viruses encoding bispecific T cell engagers as an example, the general methodology can be adapted to other virus species and transgenes. The presented workflow includes the design, cloning, rescue, and propagation of recombinant viruses. Assays to analyze replication kinetics and lytic activity of the vector as well as functionality of the isolated immunomodulator ex vivo are included, thus facilitating the generation of novel agents for further development in preclinical models and ultimately clinical translation.

Figure 1&#160;illustrates the mechanism of action of oncolytic measles viruses encoding bispecific T cell engagers. A flowchart depicting the workflow of this protocol is presented in Figure 2. Figure 3 shows an example of a modified oncolytic measles virus genome. This provides a visual representation of the specific changes applied to the measles virus anti-genome and particular fe...

Watch this Scientific Journal Video about Paramyxoviruses for Tumor-targeted Immunomodulation: Design and Evaluation Ex Vivo at JoVE.com

Paramyxoviruses for Tumor-targeted Immunomodulation: Design and Evaluation Ex Vivo

This protocol describes a detailed workflow for the generation and ex vivo characterization of oncolytic viruses for expression of immunomodulators, using measles viruses encoding bispecific T cell engagers as an example. Application and adaptation to other vector platforms and transgenes will accelerate the development of novel immunovirotherapeutics for clinical translation.

Successful cancer immunotherapy has the potential to achieve long-term tumor control. Despite recent clinical successes, there remains an urgent need for ...

This method can help address key challenges in the field of cancer immunotherapy by facilitating the development of oncolyctic vectors for targeted immunomodulation. The main advantage of the applied reverse genetic system is its versatility;therefore, vectors can be adapted to address various research questions and target tumors with diverse immune signatures. The virus propagation steps especially determining the optimal time point to harvest virus are difficult to learn from a text protocol because syncytia formation must be assessed visually over time.To begin design and clone recombinant immunomodulatory vectors as described in the manuscript. This protocol describes specific steps for the development of an oncolytic measles vaccine vector, encoding a bispecific T cell engager. To rescue measles virus from cDNA, 24 hours before transfection plate measles virus producer cells evenly on a 6 wall plate.Seed 200, 000 cells in 2 milliliters DMEM containing 10 percent FBS per well to achieve 65 to 75 percent confluency at the time of transfection. Mix 5 micrograms of recombinant DNA encoding the measles virus antigenome that will be used to transfect the cells. Appropriate plasmids and a fluorescent reporter in a total volume of 200 microliters of DMEM.Add 18.6 microliters of liposomal transfection reagent to the mixture and immediately flick the tube to mix. Incubate this transfection mix for 25 minutes at room temperature. To transfect the MV producer cells remove the medium from the 6 well plate grown to 65 to 75 percent confluency and add 1.8 milliliters of DMEM with 2 percent FBS and 50 micrograms per milliliter Kanamycin per well.Then add the transfection mix dropwise to each well and swirl carefully. Incubate the cells overnight at 37 degrees Celsius and 5 percent carbon dioxide. On the following day replace the medium with 2 milliliters of fresh DMEM with 2 percent FBS and 50 micrograms per milliliter Kanamycin and repeat this when medium becomes acidic recognized by the yellow color.Use a microscope to observe cells daily for reporter gene expression and syncytia formation. When large syncytia consisting of 20 or more cells are visible or when cells become too dense harvest the virus. 24 hours before the anticipated harvest seed approximately 1.5 million MV producer cells in 12 milliliters of DMEM with 10 percent FBS on 10 centimeter dishes to achieve 65 to 75 percent confluency at the time of virus inoculation.To collect the virus progyny use a cell scraper to carefully scrape adherent producer cells from the 6 wall plate with transfected cells. Transfer the medium containing the scraped cells into a centrifuge tube. Centrifuge for at least 2500 times G and 4 degrees Celsius for 5 minutes to remove cell debris.After centrifugation mix the cell-free supernatant with serum free medium to a final volume of 4 milliliters to prepare inoculum. Remove the medium from the 10 centimeter dish with MV producer cells and add the inoculum to the cells. Incubate for at least 2 hours at 37 degrees Celsius and 5 percent carbon dioxide.After incubation add 6 milliliters of DMEM with 10 percent FBS and incubate cells overnight. Then replace the medium with 12 milliliters of fresh DMEM with 10 percent FBS and incubate at 37 degrees Celsius and 5 percent carbon dioxide until harvesting. Observe the cells at least twice daily.Before syncytia burst when membrane disruption become visible harvest the virus. To harvest the first passage remove supernatant from the plate and add 600 microliters of serum free medium. Then use a cell lifter to scrape the cells and transfer to a clean tube.Immediately after that freeze the virus suspension in liquid nitrogen and store at 80 degrees Celsius for at least 24 hours to ensure thorough freezing. To determine titers of virus stocks in octuplicates per aliquot using 96 wall plates. First pull the producer cells from T75 cell culture flasks into 50 milliliter conical tube.Count the cells and adjust the cell suspension to 150, 000 cells per milliliter in DMEM with 10 percent FBS. Add 90 microliters of DMEM with 10 percent FBS per well of a 96 wall plate. Then add 10 microliters from one aliquot of the virus stock to all 8 wells in the first column of the plate.Mix thoroughly by pipetting up and down at least 10 times. Use a multichannel pipette to transfer 10 microliters of each well, from the first to the second column, and mix thoroughly by pipetting up and down. Repeat this for each column to obtain serial tenfold dilutions of the virus using fresh pipette tips for each dilution step.Discard 10 microliters from each well of the last column. Add 100 microliters of cell suspension with 150, 000 cells per milliliter to each well making sure there are no cell clumps. Incubate at 37 degrees Celsius, 5 percent carbon dioxide for 48 hours.Check for syncytia using a light microscope. Count syncytia in each well of the column with the highest dilution factor containing visible syncytia. For viruses encoding a fluorescent reporter, syncytia can be counted using fluorescence microscopy.For analysis of measles virus replication kinetics one day prior to infection seed 100, 000 vero cells in 1 milliliter of DMEM with 10 percent FBS per well on 12 wall plates with at least 2 wells for each time point of interest. To infect the cells replace the medium with 300 microliters of serum free medium containing the respective amount of the virus. Incubate at 37 degrees Celsius and 5 percent carbon dioxide for at least 2 hours.Remove inoculum and add 1 milliliter of DMEM with 10 percent FBS and continue incubation. At relevant time points after infection harvest viral progyny by directly scraping cells into the medium. Transfer contents from each well to an individual tube.Snap freeze in liquid nitrogen and store at 80 degrees Celsius until titration and then proceed as described in the manuscript. To begin evaluation of BTE induced cell mediated cytotoxicity by LDH release, first isolate secreted transgene products expressed by virus infected target cells and isolate immune effector cells as described in the manuscript. Then seed target cells in a U-bottom 96 wall plate and include samples as described in the manuscript.Add previously isolated immunomodulators at desired concentrations to the respective samples. Add immune defector cells at desired ratios and add medium to a total volume of 100 microliters per well. Incubate for the desired previously determined time frames at 37 degrees Celsius and 5 percent carbon dioxide.45 minutes before sample collection add 10 microliters of 10X Lysis Solution to wells containing T max samples and the corresponding medium controls and continue incubation. Centrifuge the cells at 250 times G for 4 minutes. Transfer 50 microliters of supernatant from each well to wells of a flat bottom 96 wall plate making sure not to transfer the cells.After preparing substrate solution according the manufacturer add 50 microliters to each well. Incubate at room temperature in the dark for 30 minutes or until T max samples turn deep red. After incubation add 50 microliters of stop solution to each well.Centrifuge for 1 minute at 4000 times G and then use a hollowed needle to remove air bubbles. Measure optical absorbance at 490 nanometers and calculate as described in the manuscript. After inoculation with unmodified and BTE encoding oncolytic measles viruses growth curves of the compared vectors on vero cells appear similar.Cell viability curves on mc38 murine colorectal carcinoma cells stably expressing human carcinoembryonic antigen and the MV receptors CD46 after inoculation show that lytic activity of the transgene encoding virus lags behind in the murine tumor cell line. Flow cytometry of target antigen expressing cells incubated with BTE's at five different dilutions showed BTE binding by cells in a concentration dependent manner. In immunoblot after magnetic pull down of BTE associated cells showed that when non targeting BTE's were used there were no detectable amounts of cells;whereas when targeting BTE samples were used bound cells were present in the elution fraction.BTE mediated target antigen specific and concentration dependent cytotoxicity of murine T cells is indicated by representative LDH release assay and shows that in the present example 15 percent specific cell killing was achieved at a relatively high BTE concentration of 1 microgram per milliliter compared to reference cells. While attempting this procedure, it is important to remember to regularly monitor cells to check progression of infection. Don't forget that recombinant measles vaccine strains though attenuated may be hazardous especially to immuno-suppressed individuals.Avoid exposure by following the appropriate bio safety procedures. Individuals handling viruses should be vaccinated before performing these methods. Following this procedure viral expression of further transgenes can be achieved in order to analyze virus hosts interactions and therapeutic effects.The development of these techniques has paved the way for researchers in the field of biotherapy to explore the effects of locally expressed immunomodulators in numerous tumorous entities;In Vitro, In Vivo, and also in clinical trials.

paramyxoviruses-for-tumor-targeted-immunomodulation-design-evaluation

Research

JoVE Journal

Cancer Research

9.3K visualizações.  German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT). Este método pode ajudar a enfrentar os principais desafios no campo da imunoterapia contra o câncer, facilitando o desenvolvimento de vetores oncolíticos para imunomodulação direcionada. A principal vantagem do sistema genético reverso aplicado é sua versatilidade;portanto, vetores podem ser adaptados para abordar várias questões de pesquisa e tumores alvo com diversas assinaturas imunológicas. As etapas de propagação do vírus especialmente determinando o ponto de tempo ideal par...