Flow-cytometry-based assay to study CD8⁺ T cell cytotoxicity against tumor cells

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Cancer immunotherapy, including immune checkpoint blockade (ICB), aims to harness the immune system to eliminate tumors.
• Cytotoxic CD8+ T cells are critical for tumor cell elimination in cancer immunotherapy.
• Accurate measurement of T-cell-mediated cytotoxicity is essential for developing effective immunotherapies.

Purpose of the Study:

• To present a flow cytometry-based protocol for assessing antigen-specific CD8+ T-cell cytotoxicity against tumor cells.
• To provide a versatile method for evaluating T-cell killing under various conditions and enabling immunophenotyping.
• To offer an improved alternative to existing cytotoxicity assays for cancer immunotherapy research.

Main Methods:

• Utilized ovalbumin (OVA)-specific CD8+ T cells from OT-1 transgenic mice and OVA-presenting tumor cell lines.
• Incorporated non-target cells (OVA-negative) into co-cultures to minimize non-specific killing.
• Employed flow cytometry for quantitative assessment of antigen-specific T-cell-mediated cytotoxicity.

Main Results:

• The developed protocol accurately measures CD8+ T-cell-mediated tumor cell killing.
• The method effectively distinguishes antigen-specific killing from non-specific effects.
• The protocol allows for concurrent immunophenotyping of effector and target cells.

Conclusions:

• This flow cytometry protocol provides a valuable and versatile tool for advancing cancer immunotherapy research.
• The method offers advantages over traditional assays, such as those using luciferase-expressing tumor cells.
• Accurate assessment of T-cell cytotoxicity is crucial for the development of novel cancer immunotherapies.