Related Experiment Video
Updated: Apr 12, 2026
Non-Viral Engineering of Primary Human T Cells via Homology-Mediated End-Joining Targeted Integration of Large DNA Templates
Published on: May 9, 2025
Identification and selective expansion of functionally superior T cells expressing chimeric antigen receptors
ZeNan L Chang1,2, Pamela A Silver3, Yvonne Y Chen4
1Department of Chemical and Biomolecular Engineering, University of California-Los Angeles, 420 Westwood Plaza, Boelter Hall 5531, Los Angeles, CA, 90095, USA. zenan.chang@ucla.edu.
Background:
T cells expressing chimeric antigen receptors (CARs) have shown exciting promise in cancer therapy, particularly in the treatment of B-cell malignancies. However, optimization of CAR-T cell production remains a trial-and-error exercise due to a lack of phenotypic benchmarks that are clearly predictive of anti-tumor functionality. A close examination of the dynamic changes experienced by CAR-T cells upon stimulation can improve understanding of CAR-T-cell biology and identify potential points for optimization in the production of highly functional T cells.
Methods:
Primary human T cells expressing a second-generation, anti-CD19 CAR were systematically examined for changes in phenotypic and functional responses to antigen exposure over time. Multi-color flow cytometry was performed to quantify dynamic changes in CAR-T cell viability, proliferation, as well as expression of various activation and exhaustion markers in response to varied antigen stimulation conditions.
Results:
Stimulated CAR-T cells consistently bifurcate into two distinct subpopulations, only one of which (CAR(hi)/CD25(+)) exhibit anti-tumor functions. The use of central memory T cells as the starting population and the resilience-but not antigen density-of antigen-presenting cells used to expand CAR-T cells were identified as critical parameters that augment the production of functionally superior T cells. We further demonstrate that the CAR(hi)/CD25(+) subpopulation upregulates PD-1 but is resistant to PD-L1-induced dysfunction.
Conclusions:
CAR-T cells expanded ex vivo for adoptive T-cell therapy undergo dynamic phenotypic changes during the expansion process and result in two distinct populations with dramatically different functional capacities. Significant and sustained CD25 and CAR expression upregulation is predictive of robust anti-tumor functionality in antigen-stimulated T cells, despite their correlation with persistent PD-1 upregulation. The functionally superior subpopulation can be selectively augmented by careful calibration of antigen stimulation and the enrichment of central memory T-cell type.
Insights
Optimizing chimeric antigen receptor (CAR)-T cell therapy involves identifying key cell markers. CAR(hi)/CD25+ cells show superior anti-tumor function, and central memory T cells improve CAR-T cell production.
Area of Science:
- Immunology
- Cell Therapy
- Cancer Research
Background:
- Chimeric antigen receptor (CAR)-T cell therapy shows promise for B-cell malignancies.
- Lack of predictive phenotypic benchmarks hinders CAR-T cell production optimization.
- Understanding dynamic CAR-T cell changes upon stimulation is crucial for improving therapy.
Purpose of the Study:
- To systematically examine phenotypic and functional changes in CAR-T cells after antigen exposure.
- To identify key parameters that enhance the production of functional CAR-T cells.
- To understand the role of specific markers like CD25 and PD-1 in CAR-T cell function.
Main Methods:
- Multi-color flow cytometry was used to analyze primary human T cells engineered with an anti-CD19 CAR.
- Dynamic changes in CAR-T cell viability, proliferation, and marker expression were quantified.
- Responses were assessed under varied antigen stimulation conditions.
Main Results:
- Stimulated CAR-T cells bifurcated into two subpopulations: CAR(hi)/CD25+ cells exhibited anti-tumor functions.
- Central memory T cells as the starting population and resilient antigen-presenting cells enhanced functional CAR-T cell production.
- The CAR(hi)/CD25+ subpopulation upregulated PD-1 but remained resistant to PD-L1-induced dysfunction.
Conclusions:
- Ex vivo expanded CAR-T cells yield distinct populations with varying functional capacities.
- Sustained CD25 and CAR expression upregulation predicts robust anti-tumor functionality, even with PD-1 upregulation.
- Selective augmentation of superior CAR-T cell subpopulations is achievable through optimized antigen stimulation and central memory T cell enrichment.
Related Concept Videos
01:22T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...
01:28Diversity of Antigen Receptors
Before encountering any antigen, lymphocytes express these receptors. On B cells, the antigen receptor is a membrane-bound antibody molecule called BCR; on T cells, it is a T cell receptor or TCR. B and T cell receptors are composed of two...