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Published on: June 4, 2019
Antigen-Specific T Cell Detection via Photocatalytic Proximity Cell Labeling (PhoXCELL)
Hongyu Liu1,2, Huixin Luo1,3, Qi Xue2
1Synthetic and Functional Biomolecules Center, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Insights
A new method called Photocatalytic Proximity Cell Labeling (PhoXCELL) quantifies T cell interactions. This technique uses a photosensitizer to label interacting T cells, aiding in immunotherapy development.
Area of Science:
- Immunology
- Biotechnology
- Cell Biology
Background:
- Quantitative detection of antigen-specific T cells is vital for understanding immune responses and developing immunotherapies.
- Current methods may lack the spatiotemporal resolution needed to accurately characterize cell-cell interactions.
Purpose of the Study:
- To introduce and validate Photocatalytic Proximity Cell Labeling (PhoXCELL) for spatiotemporally resolved detection and quantification of cell-cell interactions.
- To demonstrate PhoXCELL's utility in identifying antigen-specific T cells for immunotherapy applications.
Main Methods:
- Utilized dibromofluorescein (DBF) as a biocompatible photosensitizer for singlet oxygen generation upon 520 nm photoirradiation.
- Developed a nongenetic labeling strategy for oxidized proteins on cell surfaces, enabling detection of interacting cells.
- Applied PhoXCELL to dendritic cells (DCs) and T cells to quantify interaction strength and analyze gene signatures.
Main Results:
- DBF-functionalized DCs successfully labeled interacting T cells at immune synapses with spatiotemporal resolution.
- PhoXCELL quantitatively discriminated interaction strength, revealing distinct gene signatures in strongly interacting T cells.
- Simultaneously detected tumor antigen-specific CD8+ and CD4+ T cells in murine tumor models.
Conclusions:
- PhoXCELL provides a powerful, nongenetic platform for detecting and quantifying antigen-specific T cells and their interactions.
- The method enables precise characterization of T cell behavior in complex biological systems.
- PhoXCELL holds significant potential for advancing T cell receptor (TCR)-relevant personal immunotherapy research.
Abstract:
Quantitative detection and characterization of antigen-specific T cells are crucial to our understanding of immune responses as well as the development of new immunotherapies. Herein, we report a spatiotemporally resolved method for the detection and quantification of cell-cell interactions via Photocatalytic proXimity CELl Labeling (PhoXCELL). The biocompatible photosensitizer dibromofluorescein (DBF) was leveraged and optimized as a nongenetic alternative of enzymatic approaches for efficient generation of singlet oxygen upon photoirradiation (520 nm) on the cell surface, which allowed the subsequent labeling of nearby oxidized proteins with primary aliphatic amine-based probes. We demonstrated that DBF-functionalized dendritic cells (DCs) could spatiotemporally label interacting T cells in immune synapses via rapid photoirradiation with quantitatively discriminated interaction strength, which revealed distinct gene signatures for T cells that strongly interact with antigen-pulsed DCs. Furthermore, we employed PhoXCELL to simultaneously detect tumor antigen-specific CD8+ as well as CD4+ T cells from tumor-infiltrating lymphocytes and draining lymph nodes in murine tumor models, enabling PhoXCELL as a powerful platform to identify antigen-specific T cells in T cell receptor (TCR)-relevant personal immunotherapy.
