We thank L. Brockmann for critical review of the manuscript. This work was supported by NIH 1R01EB030352 and UL1 TR001873.

All animal procedures were performed with approval from the Institutional Animal Care and Use Committee (Columbia University, protocols AC-AABQ5551 and AC-AAAZ4470) using 6-8-week-old female BALB/c or CF57BL/6 mice weighing between 20-25 g. The animals were obtained from a commercial source (see Table of Materials). This protocol is structured around the &#39;days post-activation&#39; of murine T cells, and viral production begins on Day -2. Retrovirus can be stored at -80 &#176;C following initial produ...

Streamlined Protocol for Mouse CAR-T Cell Generation in Syngeneic Models

<ol>
	<li>June, C. H., Sadelain, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chimeric+antigen+receptor+therapy.">Chimeric antigen receptor therapy.</a> N Engl J Med. 379 (1), 64-73 (2018).</li><li>Duncan, B. B., Dunbar, C. E., Ishii, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Applying+a+clinical+lens+to+animal+models+of+car-t+cell+therapies.">Applying a clinical lens to animal models of car-t cell therapies.</a> Mol Ther Methods Clin Dev. 27, 17-31 (2022).</li><li>Hou, A. J., Chen, L. C., Chen, Y. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Navigating+CAR-T+cells+through+the+solid-tumour+microenvironment.">Navigating CAR-T cells through the solid-tumour microenvironment.</a> Nat Rev Drug Discov. 20 (7), 531-550 (2021).</li><li>Campesato, L. F., 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=Blockade+of+the+ahr+restricts+a+treg-macrophage+suppressive+axis+induced+by+l-kynurenine.">Blockade of the ahr restricts a treg-macrophage suppressive axis induced by l-kynurenine.</a> Nat Commun. 11 (1), 4011 (2020).</li><li>Kaneda, M. 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=Pi3kgamma+is+a+molecular+switch+that+controls+immune+suppression.">Pi3kgamma is a molecular switch that controls immune suppression.</a> Nature. 539 (7629), 437-442 (2016).</li><li>Hyrenius-Wittsten, A., Roybal, K. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Paving+new+roads+for+cars.">Paving new roads for cars.</a> Trends Cancer. 5 (10), 583-592 (2019).</li><li>Giavridis, T., 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=CAR+T+cell-induced+cytokine+release+syndrome+is+mediated+by+macrophages+and+abated+by+il-1+blockade.">CAR T cell-induced cytokine release syndrome is mediated by macrophages and abated by il-1 blockade.</a> Nat Med. 24 (6), 731-738 (2018).</li><li>Lanitis, E., 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=Optimized+gene+engineering+of+murine+CAR-T+cells+reveals+the+beneficial+effects+of+il-15+coexpression.">Optimized gene engineering of murine CAR-T cells reveals the beneficial effects of il-15 coexpression.</a> J Exp Med. 218 (2), e20192203 (2021).</li><li>Lambeth, C. R., White, L. J., Johnston, R. E., De Silva, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow+cytometry-based+assay+for+titrating+dengue+virus.">Flow cytometry-based assay for titrating dengue virus.</a> J Clin Microbiol. 43 (7), 3267-3272 (2005).</li><li>Agarwal, S., Wellhausen, N., Levine, B. L., June, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+human+crispr-engineered+CAR-T+cells.">Production of human crispr-engineered CAR-T cells.</a> J Vis Exp. 169, e62299 (2021).</li><li>JoVE Science Education Database. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lab+Animal+Research.">Lab Animal Research.</a> Sterile Tissue Harvest. , (2023).</li><li>Giordano-Attianese, G., 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+computationally+designed+chimeric+antigen+receptor+provides+a+small-molecule+safety+switch+for+t-cell+therapy.">A computationally designed chimeric antigen receptor provides a small-molecule safety switch for t-cell therapy.</a> Nat Biotechnol. 38 (4), 426-432 (2020).</li><li>Kuhn, N. F., 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=Cd40+ligand-modified+chimeric+antigen+receptor+T+cells+enhance+antitumor+function+by+eliciting+an+endogenous+antitumor+response.">Cd40 ligand-modified chimeric antigen receptor T cells enhance antitumor function by eliciting an endogenous antitumor response.</a> Cancer Cell. 35 (3), 473-488.e6 (2019).</li><li>Jin, C., Ma, J., Ramachandran, M., Yu, D., Essand, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CAR+T+cells+expressing+a+bacterial+virulence+factor+trigger+potent+bystander+antitumour+responses+in+solid+cancers.">CAR T cells expressing a bacterial virulence factor trigger potent bystander antitumour responses in solid cancers.</a> Nat Biomed Eng. 6 (7), 830-841 (2022).</li><li>Kurachi, 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=Optimized+retroviral+transduction+of+mouse+T+cells+for+in+vivo+assessment+of+gene+function.">Optimized retroviral transduction of mouse T cells for in vivo assessment of gene function.</a> Nat Protoc. 12 (9), 1980-1998 (2017).</li><li>Jafarzadeh, L., Masoumi, E., Fallah-Mehrjardi, K., Mirzaei, H. R., Hadjati, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prolonged+persistence+of+chimeric+antigen+receptor+(CAR)+T+cell+in+adoptive+cancer+immunotherapy:+Challenges+and+ways+forward.">Prolonged persistence of chimeric antigen receptor (CAR) T cell in adoptive cancer immunotherapy: Challenges and ways forward.</a> Front Immunol. 11, 702 (2020).</li><li>Elkassar, N., Gress, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+IL-7+biology+and+its+use+in+immunotherapy.">An overview of IL-7 biology and its use in immunotherapy.</a> J Immunotoxicol. 7 (1), 1-7 (2010).</li><li>Osinalde, N., 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=Simultaneous+dissection+and+comparison+of+IL-2+and+IL-15+signaling+pathways+by+global+quantitative+phosphoproteomics.">Simultaneous dissection and comparison of IL-2 and IL-15 signaling pathways by global quantitative phosphoproteomics.</a> Proteomics. 15 (2-3), 520-531 (2015).</li><li>Eremenko, E., 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=An+optimized+protocol+for+the+retroviral+transduction+of+mouse+CD4+T+cells.">An optimized protocol for the retroviral transduction of mouse CD4 T cells.</a> STAR Protoc. 2 (3), 100719 (2021).</li><li>Lewis, M. 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=A+reproducible+method+for+the+expansion+of+mouse+CD8++T+lymphocytes.">A reproducible method for the expansion of mouse CD8+ T lymphocytes.</a> J Immunol Methods. 417, 134-138 (2015).</li></ol>

This protocol describes the steps and reagents necessary for the retroviral transduction of murine T cells to generate CAR-T cells for in vivo studies. Optimizing retroviral transduction conditions achieves robust CAR expression without the need for viral concentration through ultracentrifugation or additional reagents. However, there are multiple modifications that can be applied to this methodology.
While this protocol describes the example generation of a GFP-specific CAR, these me...

Adoptive T cell therapies expressing chimeric antigen receptors (CARs) have revolutionized the field of cancer immunotherapy by harnessing the power of the adaptive immune system to specifically target and eliminate antigen-positive cancer cells1. While the success of CAR-T cell therapies targeting B cell malignancies has been clinically validated, preclinical studies performed in animal models remain vital for the development of new CARs targeting solid tumors. However, limited clinical efficacy has been demonstrated in solid tumor indications thus far, and it is becoming increasingly apparent that individual preclinical models do not accurately predict the pharmacodynamics and clinical efficacy of a living medicine2,3. Therefore, investigators have begun to expand the preclinical study of CAR-T cell products to include parallel assessments in xenograft and syngeneic models of human and murine cancers, respectively.
Unlike xenograft models, where human tumors and T cells are engrafted into immunodeficient mice, syngeneic models enable the examination of CAR-T cell responses in the context of a functional immune system. Specifically, immune-competent mice bearing syngeneic tumors provide a system to study the interaction between adoptively transferred T cells and context-specific milieus - including tumor-associated macrophages (TAMs) and regulatory T cells (Tregs) known to suppress T cell function in the tumor microenvironment (TME)4,5,6. Moreover, syngeneic models offer an additional platform to assess on-target, off-tumor toxicity, and CAR-T cell interaction with host factors that may lead to additional toxicities, including cytokine release syndrome7.
Despite these advantages, the number of syngeneic CAR-T cell studies remains limited. Notably, syngeneic models require autologous engineering of CAR-T cells from the same mouse strain and thus present an additional challenge due to the lack of methodology for efficient murine T cell transduction and ex vivo expansion2,8. This protocol outlines the methods to achieve stable CAR expression through the production of retroviral vectors and optimized T cell transduction. A schematic of the entire process is shown in Figure 1. The use of this approach demonstrates efficient retroviral transduction of murine CAR-T cells and the achievement of high CAR expression without the need for viral concentration through ultracentrifugation. Strategies to change the antigen-specificity of the CAR construct are discussed in addition to the co-expression of additional transgenes.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.45 &#956;m filters</td>
			<td>MilliporeSigma</td>
			<td>SLHVR33RS</td>
			<td></td>
		</tr>
		<tr>
			<td>1 mL syringe&#160;</td>
			<td>Fisher Scientific&#160;</td>
			<td>14-955-450</td>
			<td></td>
		</tr>
		<tr>
			<td>1.5 mL microcentrifuge tubes&#160;</td>
			<td>Fisher Scientific&#160;</td>
			<td>05-408-135</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mL syringe&#160;</td>
			<td>BD</td>
			<td>14-823-16E</td>
			<td></td>
		</tr>
		<tr>
			<td>100 &#956;m strainer</td>
			<td>Corning</td>
			<td>07-201-432</td>
			<td></td>
		</tr>
		<tr>
			<td>15 cm TC treated cell culture dishes</td>
			<td>ThermoFisher Scientific&#160;</td>
			<td>130183</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL conical tubes&#160;</td>
			<td>Falcon</td>
			<td>14-959-70C</td>
			<td></td>
		</tr>
		<tr>
			<td>40 &#956;m strainer&#160;</td>
			<td>Corning</td>
			<td>07-201-430</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL conical tubes&#160;</td>
			<td>Falcon</td>
			<td>14-959-49A</td>
			<td></td>
		</tr>
		<tr>
			<td>70 &#956;m strainer</td>
			<td>Corning</td>
			<td>07-201-431</td>
			<td></td>
		</tr>
		<tr>
			<td>Attune NxT Flow Cytometer&#160;</td>
			<td>ThermoFisher Scientific&#160;</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>BALB/C, 6-8 week old&#160;</td>
			<td>Jackson Laboratory</td>
			<td>651</td>
			<td></td>
		</tr>
		<tr>
			<td>B-Mercaptoethanol&#160;</td>
			<td>Gibco</td>
			<td>21985023</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin&#160;</td>
			<td>GOLDBIO</td>
			<td>A-420-500</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM Medium</td>
			<td>Gibco</td>
			<td>11965092</td>
			<td></td>
		</tr>
		<tr>
			<td>Dulbecco&#39;s Phosphate Buffered Saline (PBS), without Calcium and Magnesium&#160;</td>
			<td>Gibco</td>
			<td>14-190-250</td>
			<td></td>
		</tr>
		<tr>
			<td>DynaMag-2 Magnet&#160;</td>
			<td>Invitrogen</td>
			<td>12-321-D</td>
			<td></td>
		</tr>
		<tr>
			<td>EasySep Magnet&#160;</td>
			<td>Stemcell Technologies</td>
			<td>18000</td>
			<td></td>
		</tr>
		<tr>
			<td>EasySep Mouse T cell Isolation Kit</td>
			<td>Stemcell Technologies</td>
			<td>19851</td>
			<td></td>
		</tr>
		<tr>
			<td>FACS buffer&#160;</td>
			<td>BD</td>
			<td>BDB554657</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)&#160;</td>
			<td>Corning</td>
			<td>MT35011CV</td>
			<td></td>
		</tr>
		<tr>
			<td>GlutaMAX</td>
			<td>Gibco</td>
			<td>35-050-061</td>
			<td></td>
		</tr>
		<tr>
			<td>G-Rex6</td>
			<td>Wilson Wolf</td>
			<td>80240M&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES Buffer Solution&#160;</td>
			<td>Gibco</td>
			<td>15-630-080</td>
			<td></td>
		</tr>
		<tr>
			<td>Human recombinant IL-15&#160;</td>
			<td>Miltenyi Biotec</td>
			<td>130-095-765</td>
			<td></td>
		</tr>
		<tr>
			<td>Human recombinant IL-2</td>
			<td>Miltenyi Biotec</td>
			<td>130-097-748</td>
			<td></td>
		</tr>
		<tr>
			<td>Human recombinant IL-7</td>
			<td>Miltenyi Biotec</td>
			<td>130-095-363</td>
			<td></td>
		</tr>
		<tr>
			<td>Lipofectamine 3000</td>
			<td>Invitrogen</td>
			<td>L3000008</td>
			<td></td>
		</tr>
		<tr>
			<td>MEM Non-Essential Amino Acids Solution&#160;</td>
			<td>Gibco</td>
			<td>11140-050</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-CD3 BV421</td>
			<td>Biolegend</td>
			<td>100228</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-CD3/CD28 Dynabeads</td>
			<td>Gibco</td>
			<td>11-453-D</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-CD4 BV605</td>
			<td>BD</td>
			<td>563151</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-CD44 APC&#160;</td>
			<td>Biolegend</td>
			<td>103011</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-CD62L PE-Cy7</td>
			<td>Tonbo</td>
			<td>SKU 60-0621-U025</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse Anti-CD8 APC-Cy7</td>
			<td>Tonbo</td>
			<td>SKU 25-0081-U025</td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon Ti2 with Prime 95B camera&#160;</td>
			<td>Nikon</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Non-treated 24 well plates&#160;</td>
			<td>CytoOne</td>
			<td>CC7672-7524</td>
			<td></td>
		</tr>
		<tr>
			<td>Opti-MEM</td>
			<td>Gibco</td>
			<td>31-985-062</td>
			<td></td>
		</tr>
		<tr>
			<td>pCL-Eco</td>
			<td>Addgene</td>
			<td>#12371</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin Solution</td>
			<td>Gibco</td>
			<td>15-070-063</td>
			<td></td>
		</tr>
		<tr>
			<td>Phoenix Eco cells</td>
			<td>ATCC</td>
			<td>CRL-3214</td>
			<td></td>
		</tr>
		<tr>
			<td>pMDG.2</td>
			<td>Addgene</td>
			<td>#12259</td>
			<td></td>
		</tr>
		<tr>
			<td>pMSCV_PGK_GFP28z</td>
			<td>N/A</td>
			<td>Produced by R.LV.</td>
			<td></td>
		</tr>
		<tr>
			<td>Purified sfGFP</td>
			<td>N/A</td>
			<td>Produced by R.LV.</td>
			<td></td>
		</tr>
		<tr>
			<td>RetroNectin (&#39;transduction reagent&#39;)</td>
			<td>Takara Bio</td>
			<td>T100B</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Gibco</td>
			<td>21875</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological pipette 10 mL</td>
			<td>Fisher Scientific&#160;</td>
			<td>13-678-11E</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological pipette 25 mL</td>
			<td>Fisher Scientific&#160;</td>
			<td>13-678-11</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological pipette 5 mL</td>
			<td>Fisher Scientific&#160;</td>
			<td>13-678-11D</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Pyruvate</td>
			<td>Gibco</td>
			<td>11-360-070</td>
			<td></td>
		</tr>
		<tr>
			<td>TC-treated 24 well plates&#160;</td>
			<td>Corning</td>
			<td>08-772-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue&#160;</td>
			<td>Gibco</td>
			<td>15-250-061</td>
			<td></td>
		</tr>
	</tbody>
</table>

efficient generation of murine chimeric antigen receptor (car)-t cells

Engineered cell therapies utilizing chimeric antigen receptor (CAR)-T cells have achieved remarkable effectiveness in individuals with hematological malignancies and are presently undergoing development for the treatment of diverse solid tumors. So far, the preliminary evaluation of novel CAR-T cell products has predominantly taken place in xenograft tumor models using immunodeficient mice. This approach is chosen to facilitate the successful engraftment of human CAR-T cells in the experimental setting. However, syngeneic mouse models, in which tumors and CAR-T cells are derived from the same mouse strain, allow evaluation of new CAR technologies in the context of a functional immune system and comprehensive tumor microenvironment (TME). The protocol described here aims to streamline the process of mouse CAR-T cell generation by presenting standardized methods for retroviral transduction and ex vivo T cell culture. The methods described in this protocol can be applied to other CAR constructs beyond the ones used in this study to enable routine evaluation of new CAR technologies in immune-competent systems.

Author Spotlight: Enhancing CAR-T Cell Function in Syngeneic Tumor Models 

Efficient Generation of Murine Chimeric Antigen Receptor (CAR)-T Cells

Our research explores effective combinations of engineered bacteria and CAR T-cells for solid tumor treatment. It's important for us to study how these two cell therapies function within the context of a complete immune system using syngeneic models of ovarian cancer. Studying the function of CAR T-cells in syngeneic tumor models has been limited by the lack of standardized protocols for generating murine CAR T-cells.Murine T-cells are particularly difficult to transduce in culture ex vivo using traditional methods. We developed this protocol to streamline the production of murine CAR T-cells to enable study in syngeneic models that provide important context to evaluate the activity of new CAR technologies.

The protocol described here aims to standardize the process of murine T cell transduction for the generation of mouse CAR-T cells. Figure 1 provides a detailed description of the steps involved. The process begins with the production of retroviral vectors via co-transfection of viral components into Phoenix Eco cells. Figure 2 provides an image of the optimal density of Phoenix Eco cells on the day of transfection. Isolated T cells are then activated 24...

Watch this Scientific Journal Video about Enhancing CAR-T Cell Function in Syngeneic Tumor Models at JoVE.com

This protocol streamlines retroviral vector production and murine T cell transduction, facilitating the efficient generation of mouse CAR-T cells.

Engineered cell therapies utilizing chimeric antigen receptor (CAR)-T cells have achieved remarkable effectiveness in individuals with hematological ...