Generation and Optimization of Off-The-Shelf Immunotherapeutics Targeting TCR-Vβ2+ T Cell Malignancy

Key Takeaways

• Targeting a T cell receptor clone TRBV20-1, uniquely expressed by malignant T cells offers an approach to selectively target diseased T cells without affecting normal T cells.
• Through de novo sequencing, a commercially available murine Vβ2 antibody was engineered into a CAR construct, CAR-Vβ2, and a NK-based ADCC agent.
• The humanized CAR-Vβ2 T cells exhibited specific elimination of Vβ2+ malignant T cells, demonstrating efficacy both in vivo and in vitro. 

Summary

T cell malignancies pose a complex challenge in developing effective and safe immunotherapies. Despite the success of chimeric antigen receptor (CAR) T-cell therapies, they often lead to the depletion of healthy T cells, increasing susceptibility to infections. 

Researchers from the Girardi lab at the Yale School of Medicine aimed to develop novel strategies for the treatment of T cell malignancies without impacting healthy T cells.

Analysis of T cell lymphoma patients revealed that malignant cells express a specific T cell receptor (TCR) clone utilizing a single Vβ-family, known as TRBV20-1. They hypothesized that targeting these dominant TRBVs may be an effective approach to target malignant T cells without impacting normal T cells.

Utilizing REmAb de novo antibody sequencing, the amino acid sequence of a commercially available murine Vβ2 antibody was obtained. This sequence was engineered and incorporated and humanized into a second-generation CAR construct (CAR-Vβ2). CAR-Vβ2 T cells demonstrated specific elimination of Vβ2+ malignant T cells both in vivo and in vitro. 

In addition to CAR-T cells, researchers developed a natural killer (NK) cell therapy with antibody-dependent cellular cytotoxicity (ADCC). Using the same commercially available murine Vβ2 antibody, they incorporated Fc-mutations and introduced cell line mutations to engineer afucosylated antibodies with improved ADCC activity.

This innovative method holds promise for advancing targeted therapies against T cell malignancies while minimizing off-target effects on healthy T cells.