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Use of Single Chain MHC Technology to Investigate Co-agonism in Human CD8+ T Cell Activation
Published on: February 28, 2019
Increased effector-target cell conjugate formation due to HLA restricted specific antigen recognition
Ching Y Voss1, Sara Deola, Thomas A Fleisher
1Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
T cell receptor (TCR) interactions drive effector-target cell conjugates, indicating specific antigen recognition. This conjugate formation assay can detect and isolate functional cytotoxic T lymphocytes (CTLs).
Area of Science:
- Immunology
- Cellular Biology
- Cancer Research
Background:
- T cell receptor (TCR) interactions are crucial for T cell-mediated cytotoxicity and effector-target cell conjugate formation.
- The direct contribution of TCR/antigen interactions to conjugate formation and its reliability as an indicator of specific antigen recognition remain unclear, especially given antigen-independent adhesion.
- Human cytotoxic T lymphocyte (CTL) clones can adhere to target cells independently of antigen recognition.
Purpose of the Study:
- To investigate the role of TCR/HLA/antigen interactions in effector-target cell conjugate formation.
- To determine if conjugate formation can serve as a reliable indicator of specific antigen recognition by the TCR.
- To explore the potential of conjugate assays for detecting and isolating functional CTLs.
Main Methods:
- Utilized an epitope-specific CTL clone recognizing a melanoma-associated antigen (gp100:209-217) and HLA-A*0201.
- Tested CTLs against melanoma cell lines with varying expression of HLA-A*0201 and gp100.
- Analyzed effector-target cell conjugate frequency and correlated it with interferon-gamma (IFN-γ) production.
Main Results:
- TCR/HLA/antigen interactions, alongside adhesion molecules, facilitated effector-target cell conjugate formation.
- HLA-restricted antigen recognition significantly increased conjugate frequency (up to 2-fold) and CTL binding to tumor cells (50% increase).
- Increased CTLs within conjugates correlated with higher numbers of IFN-γ producing CTLs.
Conclusions:
- HLA-restricted antigen recognition plays a dominant role in effector-target cell conjugate formation.
- Conjugate formation assays show promise as a tool to detect and isolate viable, functionally active CTLs.
- This assay's ability to function without prior knowledge of the target antigen makes it suitable for enriching CTLs against novel antigens.
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