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Updated: Oct 9, 2025
Peptide:MHC Tetramer-based Enrichment of Epitope-specific T cells
Published on: October 22, 2012
A Novel Peptide-MHC Targeted Chimeric Antigen Receptor T Cell Forms a T Cell-like Immune Synapse
Stacie Shiqi Wang1,2, Kylie Luong1, Fiona Margaret Gracey3
1The Walter and Eliza Hall Institute of Medical Research, Immunology Division, Parkville, Melbourne, VIC 3052, Australia.
Abstract:
Chimeric Antigen Receptor (CAR) T cell therapy is a promising form of adoptive cell therapy that re-engineers patient-derived T cells to express a hybrid receptor specific to a tumour-specific antigen of choice. Many well-characterised tumour antigens are intracellular and therefore not accessible to antibodies at the cell surface. Therefore, the ability to target peptide-MHC tumour targets with antibodies is key for wider applicability of CAR T cell therapy in cancer. One way to evaluate the effectiveness and efficiency of ligating tumour target cells is studying the immune synapse. Here we generated a second-generation CAR to targeting the HLA-A*02:01 restricted H3.3K27M epitope, identified as a possible therapeutic target in ~75% of diffuse midline gliomas, used as a model antigen to study the immune synapse. The pMHCI-specific CAR demonstrated specificity, potent activation, cytokine secretion and cytotoxic function. Furthermore, we characterised killing kinetics using live cell imaging as well as CAR synapse confocal imaging. Here we provide evidence of robust CAR targeting of a model peptide-MHC antigen and that, in contrast to protein-specific CARs, these CARs form a TCR-like immune synapse which facilitates TCR-like killing kinetics.
Insights
Chimeric Antigen Receptor (CAR) T cell therapy now targets intracellular tumor antigens. This study shows CARs targeting peptide-MHC complexes form a T cell receptor-like immune synapse for effective cancer cell killing.
Area of Science:
- Immunology
- Oncology
- Biotechnology
Background:
- Chimeric Antigen Receptor (CAR) T cell therapy shows promise for adoptive cell therapy.
- Targeting intracellular tumor antigens is crucial for expanding CAR T cell therapy applications.
- The immune synapse is key to evaluating CAR T cell therapy effectiveness.
Purpose of the Study:
- To generate a CAR targeting the HLA-A*02:01 restricted H3.3K27M epitope, a potential target in diffuse midline gliomas.
- To investigate the immune synapse formation and function of this novel CAR.
- To evaluate CAR T cell killing kinetics against peptide-MHC targets.
Main Methods:
- Generation of a second-generation CAR targeting a specific peptide-MHC complex (H3.3K27M/HLA-A*02:01).
- Assessment of CAR specificity, activation, cytokine secretion, and cytotoxic function.
- Live cell imaging and confocal microscopy to characterize immune synapse formation and killing kinetics.
Main Results:
- The peptide-MHC-specific CAR demonstrated potent activation, cytokine secretion, and cytotoxic function.
- CAR T cells formed a T cell receptor (TCR)-like immune synapse with target cells.
- Killing kinetics were TCR-like, differing from protein-specific CARs.
Conclusions:
- This study provides evidence for robust CAR targeting of a model peptide-MHC antigen.
- CARs targeting peptide-MHC complexes form a TCR-like immune synapse.
- This mechanism facilitates TCR-like killing kinetics, expanding CAR T cell therapy potential.
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