Manufacturing Chimeric Antigen Receptor (CAR) T Cells for Adoptive Immunotherapy
December 17th, 2019
We describe an approach to reliably generate chimeric antigen receptor (CAR) T cells and test their differentiation and function in vitro and in vivo.
De-lib-er-ating a CAR T Cell product with functional competence that engraft, proliferate and has cit-el-uric activity following infusion is a key component of an effective adoptive immunotherapy. For example, in solid tumors, CAR T cells they can penetrate solid tumors and they receive optimal antigen stimulation;however, their overall engraftment and proliferation is impeded in people. The main benefit of this approach is that it can retain the quality of the CAR T cells or differentiation state of the CAR T cells without generating terminally differentiated or exhausted T cells, which would have diminished proliferative capacity or poor effective function following infusion.
This technique can be difficult because T cells are very sensitive to their cell concentration or the surface area of the vessels that their cultured in. As well as their metabolic needs. Essentially T cells need to be kept happy throughout the process, otherwise they won't grow.
To begin this procedure, set out 6-well culture dishes. Activate fresh or cryo-preserved primary human T cells by mixing them with anti-CD3 CD28 magnetic beads, at a ratio of three beads per T cell in the wells of the culture dishes. Culture the T cells in X-Vivo 15 medium supplemented with normal human AB serum, L-glutamine, he-pees and IL2.
Activate the T cells at a concentration of one million T cells per milliliter during expansion. And culture them at 37 degrees Celsius with 20%oxygen, 5%carbon-dioxide and 95%humidity. After overnight stimulation, add lentiviral supernatants to the activated T cells.
Calculate the volume of supernatants necessary to achieve a multiplicity of infection between three and five. Continue culturing the cells using the same conditions. On day three, collect a representative aliquot of the cells of cryo-preservation.
Prior to cryo-preservation, remove the magnetic beads by gently pipetting and magnetic separation. Prepare the freezing medium, which contains PBS with 0.5%DMSO. And store it at four degrees Celsius until ready to use.
Next, centrifuge the T cells at 300 times G for five minutes. Discard the supernatant and add five milliliters of PBS. Centrifuge the cells again at 300 times G for five minutes and discard the PBS.
We suspend the pellant in one milliliter of cold cryo-preservation medium. Freeze the T cells in a chilled freezing container. And store at minus 80 degrees Celsius for 48 hours.
After this, transfer the frozen cells to liquid nitrogen. Wash the rest of the T cells once in five milliliters of PBS to eliminate any residual vector. Centrifuge at 300 times G for five minutes.
Then, decant the PBS and re-suspend the cell pellant in T cell culture medium at a concentration of 500, 000 cells per milliliter. Split the T cells into two cultures designed 45 and nine. Count the T cells by flow cytometry using counting beads and monoclonal antibodies to human CD4 and CD8.
As well as a viability dye. Refeed the cultures every other day to maintain them at a concentration of 500, 000 cells per milliliter. On day five, count and cryo-preserve the day five cultures as previously described.
On day seven, wash 500, 000 cells in PBS. And re-suspend them in 100 microliters of fluorescence activated cell sorting buffer. Then, detect CAR surface protein expression by immuno-staining with a fluorescently conjugated anti-CAR 19 idio-type by flow cytometry.
On day nine count and cryo-preserve the day nine cultures as previously described. In this study the function and efficacy of CAR T cells that are harvested at varying intervals throughout X-Vivo culture are measured. Using the methods described in this video, T cells are stimulated and expanded for either three or nine days.
The cells differentiation profile as indicated by the gating strategy shown here, is analyzed by measuring the abundance of distinct glycoproteins expressed on the cell surface. A progressive shift towards effector differentiation is seen over time during X-Vivo culture. The effector function and proliferative capacity of CAR T cells in response to antigen is then assessed.
Cells that are expanded less are functionally superior to those extensively cultured over a longer duration. In a human xenograft mouse model of ALL the potency of CAR T cells harvested at different time periods is compared. The nine day cells show a dose-dependent anti-lukemic response with a complete response worth a high dose of three million;and a loss of efficacy for the low dose of 500, 000.
However, the day three cells showed persistent tumor control in both high and low doses. This response is associated with the absolute count of CAR-T 19 in the peripheral blood of mice. Overall, these results provide evidence that CAR T cells harvested earlier, outperform those harvested later.
Following this procedure, additional function assays such as seahorse assay can be performed to measure their metabolic properties such as oxygen consumption or spir-it-ed capacity. Several rounds of re-stimulation can also be performed to provide insight into their differentiation and persistence of CAR T cells. Using this work as a foundation we and other researchers are engaged in studies to abbreviate the culture process further.
It can also be extended in core approaches design for other cancer antigens. Care always have to be taken when you work with lentivirus. But even when the lentivirus is engineered to be replication incompetent.
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Overview
This article describes a method for generating chimeric antigen receptor (CAR) T cells with functional competence. It emphasizes the importance of maintaining T cell quality during the process to ensure effective adoptive immunotherapy.
Key Study Components
Area of Science
- Immunotherapy
- Cellular Biology
- Oncology
Background
- CAR T cells are engineered to target specific antigens in tumors.
- Effective engraftment and proliferation of CAR T cells are crucial for therapy success.
- Solid tumors present unique challenges for CAR T cell penetration and function.
- Maintaining T cell health throughout the culture process is essential for their effectiveness.
Purpose of Study
- To develop a reliable method for generating CAR T cells.
- To assess the differentiation and functionality of CAR T cells in vitro and in vivo.
- To improve the overall efficacy of CAR T cell therapies.
Methods Used
- Generation of CAR T cells from patient-derived T cells.
- In vitro testing of T cell differentiation and function.
- In vivo assessment of CAR T cell engraftment and activity.
- Monitoring of T cell health and metabolic needs during culture.
Main Results
- Successful generation of CAR T cells with preserved functional competence.
- Demonstrated ability of CAR T cells to proliferate and function effectively post-infusion.
- Identified key factors influencing T cell health during culture.
- Provided insights into optimizing CAR T cell therapies for solid tumors.
Conclusions
- The developed method enhances the quality of CAR T cells for therapeutic use.
- Maintaining T cell health is critical for their effectiveness in adoptive immunotherapy.
- Future studies should focus on further optimizing CAR T cell generation and function.
Frequently Asked Questions
Executive Industry Relevance
Manufacturing CAR T cells with preserved functional competence is critical for advancing adoptive immunotherapy in oncology pipelines. This method enables robust evaluation of CAR expression, differentiation, proliferative capacity, and cytolytic activity, supporting predictive confidence in preclinical models. Reliable CAR T cell production directly impacts portfolio decisions at the interface of discovery and translational research.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables interrogation of therapeutic hypotheses by generating CAR T cells targeting specific antigens.
- Supports biological de-risking through functional assessment of CAR T cell differentiation and persistence.
- Facilitates predictive confidence in target engagement and cytolytic activity in preclinical models.
Screening & Assay Development
- Prepares validated CAR T cell populations for downstream cytotoxicity and cytokine release assays.
- Standardizes measurement of CAR expression and effector function for reproducible assay outputs.
- Enables quantitative evaluation of proliferation and viability, supporting reliable compound or antigen screening.
Translational & Preclinical Research
- Aligns CAR T cell functional profiles with disease-relevant xenograft models for translational continuity.
- Supports risk-adjusted advancement by comparing efficacy of CAR T cells harvested at different culture intervals.
- Provides mechanistic de-risking by linking differentiation state to in vivo persistence and anti-tumor activity.
Pipeline & Workflow Integration
This CAR T cell manufacturing protocol bridges early discovery, assay development, and preclinical validation, enabling seamless workflow integration for immunotherapy programs.
- Discovery Biology: Supports hypothesis testing and pathway clarification via functional CAR T cell generation.
- Screening: Delivers reproducible, quantitative readouts for CAR expression and cytolytic function.
- Analytics: Provides flow cytometry-based measurements and cytokine assays for comparative analysis.
- Translational Research: Connects in vitro differentiation and function to in vivo efficacy in xenograft models.
- Enterprise Reuse: Establishes a standardized platform adaptable to other antigen targets and disease models.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in CAR T cell function.
- Operational Value: Enhances standardization, reproducibility, and scalability of CAR T cell production.
- Strategic Value: Improves go/no-go decisions and capital efficiency by enabling robust preclinical evaluation.
- Portfolio Impact: Supports risk-adjusted prioritization and advancement of immunotherapy candidates.
Implementation Considerations
- Requires expertise in T cell culture, lentiviral transduction, and flow cytometry analysis.
- Demands access to specialized cell culture facilities and analytical instrumentation.
- Necessitates cross-team standardization of cell counting, viability, and functional assays.
- Adaptable to various antigen targets and preclinical model systems with protocol optimization.
- Careful handling of lentiviral vectors is essential for biosafety and reproducibility.
