The CD20/alphaCD20 'suicide' system: novel vectors with improved safety and expression profiles and efficient
T van Meerten1, M-J Claessen, A Hagenbeek
1Jordan Laboratory for Hemato-Oncology, Department of Haematology, University Medical Center Utrecht, Heidelberglaan 100, Utrecht, The Netherlands.
Abstract:
Adoptive transfer of T lymphocytes is an attractive strategy for many experimental treatment strategies for cancer. Unfortunately, manipulated T cells could be responsible for serious adverse events. Retroviral CD20-transduced T cells may be able to control these unwanted effects. CD20-positive cells are sensitive to rituximab (RTX), a monoclonal antibody specific for CD20. This permits their selective elimination in vivo in case of adverse events. To this end, a system is required that permits efficient and safe transduction of donor T cells and effective elimination of CD20-positive T cells. We constructed different CD20-encoding retroviral vectors and investigated the impact of inclusion of the woodchuck post-transcriptional regulatory element (WPRE) and the chicken hypersensitivity site 4 insulator elements on the levels, homogeneity and stability of CD20 expression. Importantly, inclusion of either WPRE or insulator elements in the retroviral vector resulted in a dramatic improvement in the stability of CD20 expression. The insulator element also led to a much more homogeneous level of CD20 expression. We also show the efficient elimination of the CD20-transgenic T cells via RTX by different effector mechanisms. In conclusion, we have constructed CD20-encoding retroviral vectors with improved efficiency and safety profiles, which can be used as a suicide strategy.
Insights
Engineered T cells for cancer therapy can cause adverse events. This study developed CD20-transduced T cells, enabling targeted elimination with rituximab (RTX) for enhanced safety in adoptive cell therapy.
Area of Science:
- Immunology
- Gene Therapy
- Oncology
Background:
- Adoptive T cell therapy offers promise for cancer treatment but carries risks of adverse events due to manipulated T cells.
- Controlling adverse events is crucial for the clinical application of T cell-based cancer therapies.
Purpose of the Study:
- To construct CD20-encoding retroviral vectors for T cell transduction.
- To enhance the safety of T cell therapy by enabling selective elimination of manipulated T cells.
- To investigate the impact of regulatory elements on CD20 expression stability and homogeneity.
Main Methods:
- Construction of CD20-encoding retroviral vectors with and without woodchuck post-transcriptional regulatory element (WPRE) and chicken hypersensitivity site 4 insulator elements.
- Analysis of CD20 expression levels, homogeneity, and stability in transduced T cells.
- Evaluation of CD20-positive T cell elimination using rituximab (RTX) and various effector mechanisms.
Main Results:
- Inclusion of WPRE or insulator elements significantly improved the stability of CD20 expression.
- The insulator element enhanced the homogeneity of CD20 expression across T cells.
- CD20-transgenic T cells were efficiently eliminated in vivo by RTX through multiple effector mechanisms.
Conclusions:
- Developed CD20-encoding retroviral vectors offer improved efficiency and safety profiles for T cell transduction.
- These vectors provide a viable 'suicide' strategy for controlling adverse events in adoptive T cell therapy.
- Enhanced vector design facilitates safer and more effective T cell-based cancer treatments.
