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.

C.E. Engeland is listed as co-inventor of a patent regarding RNA Viruses for Cancer Immunovirotherapy owned by Heidelberg University. J.P.W. Heidbuechel has nothing to disclose.

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><tbody><tr><td>Rapid DNA Dephos &amp;amp; Ligation Kit</td><td>Roche Life Science, Mannheim, Germany</td><td>4898117001</td><td></td></tr><tr><td>CloneJET PCR Cloning Kit</td><td>Thermo Fisher Scientific, St. Leon-Rot</td><td>K1231</td><td></td></tr><tr><td>Agarose</td><td>Sigma-Aldrich, Taufkirchen, Germany</td><td>A9539-500G</td><td></td></tr><tr><td>QIAquick Gel Extraction Kit</td><td>QIAGEN, Hilden, Germany</td><td>28704</td><td></td></tr><tr><td>NEB 10-beta Competent &lt;em&gt;E. coli&lt;/em&gt;</td><td>New England Biolabs (NEB), Frankfurt/Main, Germany</td><td>C3019I</td><td></td></tr><tr><td>LB medium after Lennox</td><td>Carl Roth, Karlsruhe, Germany</td><td>X964.1</td><td></td></tr><tr><td>Ampicillin</td><td>Carl Roth, Karlsruhe, Germany</td><td>HP62.1</td><td></td></tr><tr><td>QIAquick Miniprep Kit</td><td>QIAGEN, Hilden, Germany</td><td>27104</td><td></td></tr><tr><td>Restriction enzyme HindIII-HF</td><td>New England Biolabs (NEB), Frankfurt/Main, Germany</td><td>R3104S</td><td></td></tr><tr><td>Dulbecco&#039;s Modified Eagle&#039;s Medium (DMEM)</td><td>Invitrogen, Darmstadt, Germany</td><td>31966-021</td><td></td></tr><tr><td>Fetal bovine serum (FBS)</td><td>Biosera, Boussens, France</td><td>FB-1280/500</td><td></td></tr><tr><td>FugeneHD</td><td>Promega, Mannheim, Germany</td><td>E2311</td><td>may be replaced by transfection reagent of choice</td></tr><tr><td>Kanamycin</td><td>Sigma-Aldrich, Taufkirchen, Germany</td><td>K0129</td><td></td></tr><tr><td>Vero cells</td><td>ATCC, Manassas, VA, USA</td><td>CCL81</td><td></td></tr><tr><td>B16-CD46/ B16-CD20-CD46</td><td>J. Heidbuechel, DKFZ Heidelberg</td><td></td><td>available upon request</td></tr><tr><td>Granta-519</td><td>DSMZ, Braunschweig, Germany</td><td>ACC 342</td><td></td></tr><tr><td>Opti-MEM (serum-free medium)</td><td>Gibco Life Technologies, Darmstadt, Germany</td><td>31985070</td><td></td></tr><tr><td>Colorimetric Cell Viability Kit III (XTT)</td><td>PromoKine, Heidelberg, Germany</td><td>PK-CA20-300-1000</td><td>includes XTT reagent</td></tr><tr><td>Dulbecco&#039;s Phosphate-Buffered Saline (PBS)</td><td>Gibco Life Technologies, Darmstadt, Germany</td><td>14190-094</td><td></td></tr><tr><td>QIAquick Ni-NTA Spin Columns</td><td>QIAGEN, Hilden, Germany</td><td>31014</td><td></td></tr><tr><td>Sodium chloride</td><td>Carl Roth, Karlsruhe, Germany</td><td>3957.3</td><td></td></tr><tr><td>Imidazole</td><td>Carl Roth, Karlsruhe, Germany</td><td>I5513-25G</td><td></td></tr><tr><td>Amicon Ultra-15, PLGC Ultracel-PL Membran, 10&amp;nbsp;kDa</td><td>Merck, Darmstadt, Germany</td><td>UFC901024</td><td></td></tr><tr><td>BCA Protein Assay Kit</td><td>Merck Milipore</td><td>71285-3</td><td></td></tr><tr><td>IgG from human serum</td><td>Sigma-Aldrich, Taufkirchen, Germany</td><td>I4506</td><td></td></tr><tr><td>Anti-HA-PE</td><td>Miltenyi Biotech, Bergisch Gladbach, Germany</td><td>130-092-257</td><td>RRID: AB_871939</td></tr><tr><td>Mouse IgG1, kappa Isotype Control, Phycoerythrin Conjugated, Clone MOPC-21 antibody</td><td>BD Biosciences, Heidelberg, Germany</td><td>555749</td><td>RRID: AB_396091</td></tr><tr><td>Anti-HA-biotin antibody, clone 3F10</td><td>Sigma-Aldrich, Taufkirchen, Germany</td><td>12158167001</td><td>RRID: AB_390915</td></tr><tr><td>Anti-Biotin MicroBeads</td><td>Miltenyi Biotech, Bergisch Gladbach, Germany</td><td>130-090-485</td><td></td></tr><tr><td>MS Columns</td><td>Miltenyi Biotech, Bergisch Gladbach, Germany</td><td>130-042-201</td><td></td></tr><tr><td>MiniMACS Separator</td><td>Miltenyi Biotech, Bergisch Gladbach, Germany</td><td>130-042-102</td><td></td></tr><tr><td>MACS MultiStand</td><td>Miltenyi Biotech, Bergisch Gladbach, Germany</td><td>130-042-303</td><td></td></tr><tr><td>RIPA buffer</td><td>Rockland Immunochemicals, Gilbertsville, PA, USA</td><td>MB-030-0050</td><td></td></tr><tr><td>CytoTox 96 Non-Radioactive Cytotoxicity Assay</td><td>Promega, Mannheim, Germany</td><td>G1780</td><td>includes 10x lysis solution, substrate solution (substrate mix and assay buffer), and stop solution</td></tr><tr><td>Cell lifter</td><td>Corning, Reynosa, Mexico</td><td>3008</td><td></td></tr><tr><td>10 cm dishes</td><td>Corning, Oneonta, NY, USA</td><td>430167</td><td></td></tr><tr><td>15 cm dishes</td><td>Greiner Bio-One, Frickenhausen, Germany</td><td>639160</td><td></td></tr><tr><td>96-well plates, U-bottom</td><td>TPP, Trasadingen, Switzerland</td><td>92097</td><td></td></tr><tr><td>96-well plates, flat bottom</td><td>Neolab, Heidelberg, Germany</td><td>353072</td><td></td></tr><tr><td>6-well plates</td><td>Neolab, Heidelberg, Germany</td><td>353046</td><td></td></tr><tr><td>12-well plates</td><td>Neolab, Heidelberg, Germany</td><td>353043</td><td></td></tr><tr><td>50 mL tubes</td><td>nerbe plus, Winsen/Luhe, Germany</td><td>02-572-3001</td><td></td></tr><tr><td>T175 cell culture flasks</td><td>Thermo Fisher Scientific, St. Leon-Rot</td><td>159910</td><td></td></tr><tr><td>0.22 &amp;micro;m filters</td><td>Merck, Darmstadt, Germany</td><td>SLGPM33RS</td><td></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 ...

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

Research

JoVE Journal

Cancer Research

9.4K Views.  German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT). Deze methode kan helpen bij het aanpakken van belangrijke uitdagingen op het gebied van kankerimmunotherapie door de ontwikkeling van oncolyctische vectoren voor gerichte immunomodulatie te vergemakkelijken. Het belangrijkste voordeel van het toegepaste omgekeerde genetische systeem is de veelzijdigheid; daarom kunnen vectoren worden aangepast om verschillende onderzoeksvragen aan te pakken en tumoren met diverse immuunhandtekeningen te targeten. De virus voortplanting stappen met name het be...

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

Ex vivo Expansion of Tumor-reactive T Cells by Means of Bryostatin 1/Ionomycin and the Common Gamma Chain Cytokines Formulation

It was reported that breast cancer patients have pre-existing immune responses against their tumors1,2. However, such immune responses fail to provide complete protection against the development or recurrence of breast cancer. To overcome this problem by increasing the frequency of tumor-reactive T cells, adoptive immunotherapy has been employed. A variety of protocols have been used for the expansion of tumor-specific T cells. These protocols, however, are restricted to the use of tumor antigens ex vivo for the activation of antigen-specific T cells. Very recently, common gamma chain cytokines such as IL-2, IL-7, IL-15, and IL-21 have been used alone or in combination for the enhancement of anti-tumor immune responses3. However, it is not clear what formulation would work best for the expansion of tumor-reactive T cells. Here we present a protocol for the selective activation and expansion of tumor-reactive T cells from the FVBN202 transgenic mouse model of HER-2/neu positive breast carcinoma for use in adoptive T cell therapy of breast cancer. The protocol includes activation of T cells with bryostatin-1/ionomycin (B/I) and IL-2 in the absence of tumor antigens for 16 hours. B/I activation mimics intracellular signals that result in T cell activation by increasing protein kinase C activity and intracellular calcium, respectively4. This protocol specifically activates tumor-specific T cells while killing irrelevant T cells. The B/I-activated T cells are cultured with IL-7 and IL-15 for 24 hours and then pulsed with IL-2. After 24 hours, T cells are washed, split, and cultured with IL-7 + IL-15 for additional 4 days. Tumor-specificity and anti-tumor efficacy of the ex vivo expanded T cells is determined.

Ex vivo Expansion of Tumor-reactive T Cells by Means of Bryostatin 1/Ionomycin and the Common Gamma Chain Cytokines Formulation

An efficient protocol for the ex vivo expansion of tumor-reactive T cells from tumor-draining lymph nodes or other secondary lymphoid tissues of tumor-bearing hosts is described. This protocol selectively expands tumor-specific T cells for use in adoptive immunotherapy of breast cancer.

It was reported that breast cancer patients have pre-existing immune responses against their tumors1,2. However, such immune responses fail to provide ...

Immunology and Infection

Generation of Multivirus-specific T Cells to Prevent/treat Viral Infections after Allogeneic Hematopoietic Stem Cell Transplant

Viral infections cause morbidity and mortality in allogeneic hematopoietic stem cell transplant (HSCT) recipients. We and others have successfully generated and infused T-cells specific for Epstein Barr virus (EBV), cytomegalovirus (CMV) and Adenovirus (Adv) using monocytes and EBV-transformed lymphoblastoid cell (EBV-LCL) gene-modified with an adenovirus vector as antigen presenting cells (APCs). As few as 2x105/kg trivirus-specific cytotoxic T lymphocytes (CTL) proliferated by several logs after infusion and appeared to prevent and treat even severe viral disease resistant to other available therapies. The broader implementation of this encouraging approach is limited by high production costs, complexity of manufacture and the prolonged time (4-6 weeks for EBV-LCL generation, and 4-8 weeks for CTL manufacture &#x2013; total 10-14 weeks) for preparation. To overcome these limitations we have developed a new, GMP-compliant CTL production protocol. First, in place of adenovectors to stimulate T-cells we use dendritic cells (DCs) nucleofected with DNA plasmids encoding LMP2, EBNA1 and BZLF1 (EBV), Hexon and Penton (Adv), and pp65 and IE1 (CMV) as antigen-presenting cells. These APCs reactivate T cells specific for all the stimulating antigens. Second, culture of activated T-cells in the presence of IL-4 (1,000U/ml) and IL-7 (10ng/ml) increases and sustains the repertoire and frequency of specific T cells in our lines. Third, we have used a new, gas permeable culture device (G-Rex) that promotes the expansion and survival of large cell numbers after a single stimulation, thus removing the requirement for EBV-LCLs and reducing technician intervention. By implementing these changes we can now produce multispecific CTL targeting EBV, CMV, and Adv at a cost per 106 cells that is reduced by &gt;90%, and in just 10 days rather than 10 weeks using an approach that may be extended to additional protective viral antigens. Our FDA-approved approach should be of value for prophylactic and treatment applications for high risk allogeneic HSCT recipients.

A rapid, simple and cost-effective protocol for the generation of donor-derived multivirus-specific CTLs (rCTL) for infusion to allogeneic hematopoietic stem cell transplant (HSCT) recipients at risk of developing CMV, Adv or EBV infections. This manufacturing process is GMP-compliant and should ensure the broader implementation of T-cell immunotherapy beyond specialized centers.

Viral infections cause morbidity and mortality in allogeneic hematopoietic stem cell transplant (HSCT) recipients. We and others have successfully ...

Genome-wide RNAi Screening to Identify Host Factors That Modulate Oncolytic Virus Therapy

High-throughput genome-wide RNAi (RNA interference) screening technology has been widely used for discovering host factors that impact&#160;virus replication. Here we present the application of this technology to uncovering host targets that specifically modulate the replication of Maraba virus, an oncolytic rhabdovirus, and vaccinia virus with the goal of enhancing therapy. While the protocol has been tested for use with oncolytic Maraba virus and oncolytic vaccinia virus, this approach is applicable to other oncolytic viruses and can also be utilized for identifying host targets that modulate virus replication in mammalian cells in general. This protocol describes the development and validation of an assay for high-throughput RNAi screening in mammalian cells, the key considerations and preparation steps important for conducting a primary high-throughput RNAi screen, and a step-by-step guide for conducting a primary high-throughput RNAi screen; in addition, it broadly outlines the methods for conducting secondary screen validation and tertiary validation studies. The benefit of high-throughput RNAi screening is that it allows one to catalogue, in an extensive and unbiased fashion, host factors that modulate any aspect of virus replication for which one can develop an in vitro assay such as infectivity, burst size, and cytotoxicity. It has the power to uncover biotherapeutic targets unforeseen based on current knowledge.

Here we describe a protocol for employing high-throughput RNAi screening to uncover host targets that can be manipulated to enhance oncolytic virus therapy, specifically rhabodvirus and vaccinia virus therapy, but it can be readily adapted to other oncolytic virus platforms or for discovering host genes that modulate virus replication generally.

High-throughput genome-wide RNAi (RNA interference) screening technology has been widely used for discovering host factors that impact&#160;virus ...

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity

In vivo models of pancreatic cancer provide invaluable tools for studying disease dynamics, immune infiltration and new therapeutic strategies. The orthotopic murine model can be performed on large cohorts of immunocompetent mice simultaneously, is relatively inexpensive and preserves the cognate tissue microenvironment. The quantification of T cell infiltration and cytotoxic activity within orthotopic tumors provides a useful indicator of an antitumoral response.
This protocol describes the methodology for surgical generation of orthotopic pancreatic tumors by injection of a low number of syngeneic tumor cells resuspended in 5 &#181;L basement membrane directly into the pancreas. Mice bearing orthotopic tumors take approximately 30 days to reach endpoint, at which point tumors can be harvested and processed for characterization of tumor-infiltrating T cell activity. Rapid enzymatic digestion using collagenase and DNase allows a single-cell suspension to be extracted from tumors. The viability and cell surface markers of immune cells extracted from the tumor are preserved; therefore, it is appropriate for multiple downstream applications, including flow-assisted cell sorting of immune cells for culture or RNA extraction, flow cytometry analysis of immune cell populations. Here, we describe the ex vivo stimulation of T cell populations for intracellular cytokine quantification (IFN&#947; and TNF&#945;) and degranulation activity (CD107a) as a measure of overall cytotoxicity. Whole-tumor digests were stimulated with phorbol myristate acetate and ionomycin for 5 h, in the presence of anti-CD107a antibody in order to upregulate cytokine production and degranulation. The addition of brefeldin A and monensin for the final 4 h was performed to block extracellular transport and maximize cytokine detection. Extra- and intra-cellular staining of cells was then performed for flow cytometry analysis, where the proportion of IFN&#947;+, TNF&#945;+ and CD107a+ CD4+ and CD8+ T cells was quantified.
This method provides a starting base to perform comprehensive analysis of the tumor microenvironment.

Generation of Orthotopic Pancreatic Tumors and Ex vivo Characterization of Tumor-Infiltrating T Cell Cytotoxicity

This protocol describes the surgical generation of orthotopic pancreatic tumors and the rapid digestion of freshly isolated murine pancreatic tumors. Following digestion, viable immune cell populations can be used for further downstream analysis, including ex vivo stimulation of T cells for intracellular cytokine detection by flow cytometry.

In vivo models of pancreatic cancer provide invaluable tools for studying disease dynamics, immune infiltration and new therapeutic strategies. The ...

Tumor Transplantation for Assessing the Dynamics of Tumor-Infiltrating CD8+ T Cells in Mice

T cell-mediated immunity plays a crucial role in immune responses against tumors, with cytotoxic T lymphocytes (CTLs) playing the leading role in eradicating cancerous cells. However, the origins and replenishment of tumor antigen-specific CD8+ T cells within the tumor microenvironment (TME) remain obscure. This protocol employs the B16F10-OVA melanoma cell line, which stably expresses the surrogate neoantigen, ovalbumin (OVA), and TCR transgenic OT-I mice, in which over 90% of CD8+ T cells specifically recognize the OVA-derived peptide OVA257-264 (SIINFEKL) bound to the class I major histocompatibility complex (MHC) molecule H2-Kb. These features enable the study of antigen-specific T cell responses during tumorigenesis.
Combining this model with tumor transplantation surgery, tumor tissues from donors were transplanted into tumor-matched syngeneic recipient mice to precisely trace the influx of recipient-derived immune cells into transplanted donor tissues, allowing the analysis of the immune responses of tumor-inherent and periphery-originated antigen-specific CD8+ T cells. A dynamic transition was found to occur between these two populations. Collectively, this experimental design has provided another approach to precisely investigate the immune responses of CD8+ T cells in TME, which will shed new light on tumor immunology.

Tumor Transplantation for Assessing the Dynamics of Tumor-Infiltrating CD8+ T Cells in Mice

Here, we present a tumor transplantation protocol for the characterization of tumor-inherent and periphery-derived tumor-infiltrated lymphocytes in a mouse tumor model. Specific tracing of the influx of recipient-derived immune cells with flow cytometry reveals the dynamics of the phenotypic and functional changes of these cells during antitumor immune responses.

T cell-mediated immunity plays a crucial role in immune responses against tumors, with cytotoxic T lymphocytes (CTLs) playing the leading role in ...

In Vivo Immunogenicity Screening of Tumor-Derived Extracellular Vesicles by Flow Cytometry of Splenic T Cells

Immunogenic cell death of tumors, caused by chemotherapy or irradiation, can trigger tumor-specific T cell responses by releasing danger-associated molecular patterns and inducing the production of type I interferon. Immunotherapies, including checkpoint inhibition, primarily rely on preexisting tumor-specific T cells to unfold a therapeutic effect. Thus, synergistic therapeutic approaches that exploit immunogenic cell death as an intrinsic anti-cancer vaccine may improve their responsiveness. However, the spectrum of immunogenic factors released by cells under therapy-induced stress remains incompletely characterized, especially regarding extracellular vesicles (EVs). EVs, nano-scale membranous particles emitted from virtually all cells, are considered to facilitate intercellular communication and, in cancer, have been shown to mediate cross-priming against tumor antigens. To assess the immunogenic effect of EVs derived from tumors under various conditions, adaptable, scalable, and valid methods are sought-for. Therefore, herein a relatively easy and robust approach is presented to assess EVs' in vivo immunogenicity. The protocol is based on flow cytometry analysis of splenic T cells after in vivo immunization of mice with EVs, isolated by precipitation-based assays from tumor cell cultures under therapy or steady-state conditions. For example, this work shows that oxaliplatin exposure of B16-OVA murine melanoma cells resulted in the release of immunogenic EVs that can mediate the activation of tumor-reactive cytotoxic T cells. Hence, screening of EVs via in vivo immunization and flow cytometry identifies conditions under which immunogenic EVs can emerge. Identifying conditions of immunogenic EV release provides an essential prerequisite to testing EVs' therapeutic efficacy against cancer and exploring the underlying molecular mechanisms to ultimately unveil new insights into EVs' role in cancer immunology.

In Vivo Immunogenicity Screening of Tumor-Derived Extracellular Vesicles by Flow Cytometry of Splenic T Cells

This manuscript describes how to assess in vivo immunogenicity of tumor cell-derived extracellular vesicles (EVs) using flow cytometry. EVs derived from tumors undergoing treatment-induced immunogenic cell death seem particularly relevant in tumor immunosurveillance. This protocol exemplifies the assessment of oxaliplatin-induced immunostimulatory tumor EVs but can be adapted to various settings.

Immunogenic cell death of tumors, caused by chemotherapy or irradiation, can trigger tumor-specific T cell responses by releasing danger-associated ...

Experimental Melanoma Immunotherapy Model Using Tumor Vaccination with a Hematopoietic Cytokine

Fms-like tyrosine kinase 3 ligand (Flt3L) is a hematopoietic cytokine that promotes the survival and differentiation of dendritic cells (DCs). It has been used in tumor vaccines to activate innate immunity and enhance antitumor responses. This protocol demonstrates a therapeutic model using cell-based tumor vaccine consisting of Flt3L-expressing B16-F10 melanoma cells along with phenotypic and functional analysis of immune cells in the tumor microenvironment (TME). Procedures for cultured tumor cell preparation, tumor implantation, cell irradiation, tumor size measurement, intratumoral immune cell isolation, and flow cytometry analysis are described. The overall goal of this protocol is to provide a preclinical solid tumor immunotherapy model, and a research platform to study the relationship between tumor cells and infiltrating immune cells. The immunotherapy protocol described here can be combined with other therapeutic modalities, such as immune checkpoint blockade (anti-CTLA-4, anti-PD-1, anti-PD-L1 antibodies) or chemotherapy in order to improve the cancer therapeutic effect of melanoma.

The protocol presents a cancer immunotherapy model using cell-based tumor vaccination with Flt3L-expressing B16-F10 melanoma. This protocol demonstrates the procedures, including preparation of cultured tumor cells, tumor implantation, cell irradiation, measurement of tumor growth, isolation of intratumoral immune cells, and flow cytometry analysis.

Fms-like tyrosine kinase 3 ligand (Flt3L) is a hematopoietic cytokine that promotes the survival and differentiation of dendritic cells (DCs). It has been ...

Handling of the Cotton Rat in Studies for the Pre-clinical Evaluation of Oncolytic Viruses

Oncolytic viruses are a novel anticancer therapy with the ability to target tumor cells, while leaving healthy cells intact. For this strategy to be successful, recent studies have shown that involvement of the host immune system is essential. Therefore, oncolytic virotherapy should be evaluated within the context of an immunocompetent model. Furthermore, the study of antitumor therapies in tolerized animal models may better recapitulate results seen in clinical trials. Cotton rats, commonly used to study respiratory viruses, are an attractive model to study oncolytic virotherapy as syngeneic models of mammary carcinoma and osteosarcoma are well established. However, there is a lack of published information on the proper handling procedure for these highly excitable rodents. The handling and capture approach outlined minimizes animal stress to facilitate experimentation. This technique hinges upon the ability of the researcher to keep calm during handling and perform procedures in a timely fashion. Finally, we describe how to prepare cotton rat mammary tumor cells for consistent subcutaneous tumor formation, and how to perform intratumoral and intraperitoneal injections. These methods can be applied to a wide range of studies furthering the development of the cotton rat as a relevant pre-clinical model to study antitumor therapy.

Cotton rats are extremely excitable and have a strong flight-or-fight response. A handling method optimized to reduce the stress of the animals is described which will make cotton rats more accessible as a preclinical model.

Oncolytic viruses are a novel anticancer therapy with the ability to target tumor cells, while leaving healthy cells intact.  For this strategy to be ...

Medicine

Tailoring In Vivo Cytotoxicity Assays to Study Immunodominance in Tumor-specific CD8+ T Cell Responses

Carboxyfluorescein succinimidyl ester (CFSE)-based in vivo cytotoxicity assays enable sensitive and accurate quantitation of CD8+ cytolytic T lymphocyte (CTL) responses elicited against tumor- and pathogen-derived peptides. They offer several advantages over traditional killing assays. First, they permit the monitoring of CTL-mediated cytotoxicity within architecturally intact secondary lymphoid organs, typically in the spleen. Second, they allow for mechanistic studies during the priming, effector and recall phases of CTL responses. Third, they provide useful platforms for vaccine/drug efficacy testing in a truly in vivo setting. Here, we provide an optimized protocol for the examination of concomitant CTL responses against more than one peptide epitope of a model tumor antigen (Ag), namely, simian virus 40 (SV40)-encoded large T Ag (T Ag). Like most other clinically relevant tumor proteins, T Ag harbors many potentially immunogenic peptides. However, only four such peptides induce detectable CTL responses in C57BL/6 mice. These responses are consistently arranged in a hierarchical order based on their magnitude, which forms the basis for TCD8 &#8220;immunodominance&#8221; in this powerful system. Accordingly, the bulk of the T Ag-specific TCD8 response is focused against a single immunodominant epitope while the other three epitopes are recognized and responded to only weakly. Immunodominance compromises the breadth of antitumor TCD8 responses and is, as such, considered by many as an impediment to successful vaccination against cancer. Therefore, it is important to understand the cellular and molecular factors and mechanisms that dictate or shape TCD8 immunodominance. The protocol we describe here is tailored to the investigation of this phenomenon in the T Ag immunization model, but can be readily modified and extended to similar studies in other tumor models. We provide examples of how the impact of experimental immunotherapeutic interventions can be measured using in vivo cytotoxicity assays.

Tailoring In Vivo Cytotoxicity Assays to Study Immunodominance in Tumor-specific CD8+ T Cell Responses

We describe here a flow cytometry-based in vivo killing assay that enables examination of immunodominance in cytotoxic T lymphocyte (CTL) responses to a model tumor antigen. We provide examples of how this elegant assay may be employed for mechanistic studies and for drug efficacy testing.

Carboxyfluorescein succinimidyl ester (CFSE)-based in vivo cytotoxicity assays enable sensitive and accurate quantitation of CD8+ cytolytic T lymphocyte ...

Rapid In Vivo Assessment of Adjuvant's Cytotoxic T Lymphocytes Generation Capabilities for Vaccine Development

The assessment of modern sub-unit vaccines reveals that the generation of neutralizing antibodies is important but not sufficient for adjuvant selection. Therefore, adjuvants with both humoral and cellular immuno-stimulatory capabilities that are able to promote cytotoxic T lymphocytes (CTL) responses are urgently needed. Thus, faithful monitoring of adjuvant candidates that induce cross-priming and subsequently enhance CTL generation represents a crucial step in vaccine development. In here we present an application for a method that uses SIINFEKL-specific (OT-I) T cells to monitor the cross-presentation of the model antigen ovalbumin (OVA) in vivo in the presence of different adjuvant candidates. This method represents a rapid test to select adjuvants with the best cross-priming capabilities. The proliferation of CD8+ T cells is the most valuable indication of cross-priming and it is also regarded as a correlate of adjuvant-induced cross-presentation. This feature can be evaluated in different immune organs like lymph nodes and spleen. The extent of the CTL generation can also be monitored, thereby giving insights on the nature of a local (draining lymph node mainly) or a systemic response (distant lymph nodes and/or spleen). This technique further allows multiple modifications for testing drugs that can inhibit specific cross-presentation pathways and also offers the possibility to be used in different strains of conventional and genetically modified mice. In summary, the application that we present here will be useful for vaccine laboratories in industry or academia that develop or modify chemical adjuvants for vaccine research and development.

Rapid In Vivo Assessment of Adjuvant's Cytotoxic T Lymphocytes Generation Capabilities for Vaccine Development

We present here an application for a standard immunological technique (CFSE stained OT-I proliferation) intended to rapidly monitor adjuvant-mediated cytotoxic T lymphocyte (CTL) generation in vivo. This fast estimation of CTL capacities is useful for the development of prophylactic vaccines against intracellular pathogens as well as therapeutic cancer vaccines.

The assessment of modern sub-unit vaccines reveals that the generation of neutralizing antibodies is important but not sufficient for adjuvant selection. ...

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

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