Engineering a Dual Specificity γδ T-Cell Receptor for Cancer Immunotherapy

Area of Science:

• Immunology
• Cancer Biology
• Molecular Engineering

Background:

• Gamma delta (γδ) T-cells bridge innate and adaptive immunity, offering immune surveillance against cancer.
• The Vγ9Vδ2 γδ T-cell receptor (TCR) can be engineered into T-cells to target phosphoantigens (PAgs).
• Current cancer immunotherapies utilize γδ TCR-engineered T-cells under clinical investigation.

Purpose of the Study:

• To enhance the cancer specificity of the G115 γδ TCR by incorporating a tumor-binding peptide.
• To investigate the efficacy of dual-specific T-cells against both PAg-expressing and αvβ6-expressing tumor cells.
• To evaluate the impact of peptide insertion on T-cell activation and cytokine release.

Main Methods:

• Genetic modification of the G115 γδ TCR by inserting a 12mer peptide derived from the foot and mouth disease virus A20 peptide into the CDR3 δ2 region.
• Selection of the A20 peptide for its high-affinity binding to αvβ6 integrin, expressed on various solid tumors.
• Assessment of T-cell-mediated cytotoxicity against PAg-presenting and αvβ6-expressing tumor cells.
• Measurement of interferon (IFN)-γ release upon T-cell activation.

Main Results:

• The engineered G115 + A12 T-cells demonstrated enhanced cytolytic activity against PAg-presenting K562 cells compared to control G115 cells.
• The modified T-cells successfully killed both PAg-expressing and αvβ6-expressing tumor cells, indicating dual specificity.
• IFN-γ release was observed upon activation with either target antigen, confirming T-cell responsiveness.
• The results highlight the importance of the CDR3 δ2 region length for optimal PAg recognition.

Conclusions:

• Insertion of a tumor-binding peptide into the G115 γδ TCR CDR3 δ2 region broadens its cancer specificity.
• The novel dual-specificity approach using G115 + A12 T-cells offers a promising strategy for cancer immunotherapy.
• This engineered T-cell approach combines PAg recognition with targeting of tumor-specific integrins for improved cancer cell killing.