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Updated: Oct 4, 2025
Spatial and Temporal Control of T Cell Activation Using a Photoactivatable Agonist
Published on: April 25, 2018
Light-Controllable Binary Switch Activation of CAR T Cells
Aya Kobayashi1,2,3, Alberto Nobili1,2,3,4, Steven C Neier1,2,3,5
1Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.
Abstract:
Major challenges to chimeric antigen receptor (CAR) T cell therapies include uncontrolled immune activity, off-tumor toxicities and tumor heterogeneity. To overcome these challenges, we engineered CARs directed against small molecules. By conjugating the same small molecule to distinct tumor-targeting antibodies, we show that small molecule specific-CAR T cells can be redirected to different tumor antigens. Such binary switches allow control over the degree of CAR T cell activity and enables simultaneous targeting of multiple tumor-associated antigens. We also demonstrate that ultraviolet light-sensitive caging of small molecules blocks CAR T cell activation. Exposure to ultraviolet light, uncaged small molecules and restored CAR T cell-mediated killing. Together, our data demonstrate that a light-sensitive caging system enables an additional level of control over tumor cell killing, which could improve the therapeutic index of CAR T cell therapies.
Insights
Researchers developed a novel small molecule-based system to control chimeric antigen receptor (CAR) T cell therapy. This light-sensitive system enhances tumor targeting and reduces side effects, improving CAR T cell therapy safety and efficacy.
Area of Science:
- Immunology
- Biotechnology
- Cancer Therapy
Background:
- Chimeric antigen receptor (CAR) T cell therapies face challenges like uncontrolled immune activity, off-tumor toxicities, and tumor heterogeneity.
- Current CAR T cell therapies lack precise control over immune cell activity and tumor targeting.
- Developing strategies for enhanced control and specificity is crucial for improving CAR T cell therapy's therapeutic index.
Purpose of the Study:
- To engineer a controllable CAR T cell system using small molecules for enhanced specificity and safety.
- To demonstrate the ability to redirect CAR T cells to different tumor antigens using small molecule-antibody conjugates.
- To investigate the use of a light-sensitive system for temporal and spatial control of CAR T cell activation.
Main Methods:
- Engineered CARs that recognize small molecules instead of direct tumor antigens.
- Conjugated small molecules to distinct tumor-targeting antibodies for antigen redirection.
- Utilized ultraviolet light-sensitive caging to control small molecule availability and CAR T cell activation.
- Assessed CAR T cell-mediated killing in response to light-induced uncaging of small molecules.
Main Results:
- Small molecule-specific CAR T cells were successfully redirected to target distinct tumor antigens.
- The system demonstrated binary control over CAR T cell activity, enabling simultaneous targeting of multiple antigens.
- Ultraviolet light-sensitive caging effectively blocked CAR T cell activation until light exposure.
- Light-induced uncaging restored CAR T cell-mediated tumor cell killing, demonstrating precise control.
Conclusions:
- A novel small molecule-based CAR T cell system offers enhanced control over immune activity and tumor targeting.
- The light-sensitive caging mechanism provides an additional layer of safety and specificity for CAR T cell therapies.
- This approach has the potential to significantly improve the therapeutic index and broaden the applicability of CAR T cell therapies.
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