Antigen-Specific T Cell Detection via Photocatalytic Proximity Cell Labeling (PhoXCELL)

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.

Phototherapy with physically and molecularly produced light for Alzheimer’s disease

“…Over the past decades, numerous photolabile reactions have been broadly explored in photochemistry and biological studies [14] , and several photolabile moieties have been widely applied [14-15] . Among these photolabile moieties, diazirine is very attractive due to its excellent light sensitivity and its small size as a tag [16] .…”

Switching of Photocatalytic Tyrosine/Histidine Labeling and Application to Photocatalytic Proximity Labeling

“…The compounds shown in Figure 2 were screened as candidate photocatalysts. Ru(bpy) 3 Cl 2 ( 2 ) [ 28 ], fluorescein ( 3 ) [ 28 ], dibromofluorescein ( 4 ) [ 29 , 30 , 31 ], rhodamine 123 ( 5 ) [ 32 ], rhodamine B ( 6 ) [ 28 ], BODIPY ( 7 ) [ 33 ], halo-BODIPYs ( 8–11 ) [ 34 ], iodo-coumarin ( 12 ), eosin Y ( 13 ) [ 28 ], rose bengal ( 14 ) [ 28 ], ATTO465-CO 2 H ( 15 ) [ 27 ], and riboflavin ( 16 ) [ 35 ] were selected as candidate catalysts based on two properties: (a) their ability to be excited by visible light stimulation and (b) their known activities as catalysts for SET or as photosensitizers to produce 1 O 2 . Each dye also exhibits a different excitation spectrum, and experiments were conducted at a wavelength of either 455 or 540 nm, which is the appropriate light-emitting diode (LED) illumination source, for 5 min on ice.…”

Recent Advances in Quinone Methide Chemistry for Protein-Proximity Capturing

“…7,8 Till now, QMC has been broadly utilized in the study of various functional molecules. 9,10 Over the past few decades, methods relying on QMC have served as versatile tools in the study of biological systems. Quinone methide based probes have been extensively designed, synthesized, and utilized in protein fluorescent labeling, protein degradation, clinic diagnosis, drug delivery systems, etc.…”

“…For instance, the time-resolved regulation of proteins has been achieved at the first stage. 9 Then, in the release of the caged group through formation of a QMI using a wide range of triggers, the trapping of proximate proteins has been demonstrated to be rather efficient. 9 The rapidly development of applications utilizing QMC indicates the importance of this tool in a broad area including chemical biology, organic chemistry, and material science.…”