CAR-iNKT Cells Targeting Clonal TCRVβ Chains as a Precise Strategy to Treat T Cell Lymphoma

Rowan, A. G., Ponnusamy, K., Ren, H., Taylor, G. P., Cook, L. B. M., Karadimitris, A. (2023). CAR-iNKT cells targeting clonal TCRVB chains as a precise strategy to treat T cell lymphoma. Front Immunol 14, 1118681. https://doi.org/10.3389/fimmu.2023.1118681.

Abstract

With 22 functional T cell receptor (TCR)Vβ subunit families making up the normal T cell repertoire, signals from these cell surface receptors often determine the fate of normal cells. However, mutations in TCR signaling proteins are frequently associated with peripheral T cell lymphomas (TCLs), including adult T cell leukemia/lymphoma (ATL), which indicates a driving role for TCRs in TCL oncogenesis. As TCL and ATL are clonal in nature, tumour cells typically express a single TCRVβ subunit with no bias in the usage of TCRVβ subunit families. Consequently, targeting the specific TCRVβ subunit presents a promising therapeutic approach that is highly selective and tumour-specific.

As a proof-of-concept, the Karadimitris Lab at Imperial College London engineered chimeric antigen receptor (CAR) constructs using both conventional T cells and invariant natural killer T cells (iNKT) as effectors. To initiate their CAR engineering efforts, four commercially available monoclonal antibodies (mAbs), each specifically targeting different TCRVβ subunits (TCRVβ1, TCRVβ2, TCRVβ8, and TCRVβ11), were identified. Three of these mAbs were sequenced using Rapid Novor’s REmAb^® antibody sequencing service to obtain the exact amino acid sequences of their heavy and light chain variable regions. With these protein sequences on hand, researchers from the Karadimitris Lab were able to proceed in engineering constructs of therapeutic anti-TCRVβ CAR-iNKT cells that selectively kill their cognate tumour targets.

De novo protein sequencing is a powerful mass spectrometry-based technique with the ability to provide sequence information without the need for cells or genetic material. Securing the amino acid sequence ensures a foundation for downstream in silico design and engineering applications.

Graphical Abstract

Key Takeaways

• The Karadimitris Lab generated anti-TCRVβ CAR-iNKT cells to demonstrate the proof-of-concept targeting of TCRVβ subunits as a promising approach to generating ‘off-the-shelf’ immunotherapies for TCLs, such as ATL.
• The amino acid sequences of three commercially available mAbs were obtained via de novo protein sequencing providing the sequence information required for downstream engineering and optimization of CAR-iNKT cell constructs.