Genetic manipulation of donor T cells to control Graft versus Host disease (GvHD)

1. Genetic manipulation of donor T cells to control Graft versus Host disease (GvHD) Jordan Laboratory for hemato-oncology Hematology Department Eric Lammertsma - Tineke Lenstra - Hiljanne van der Meer Tom van Meerten – Samantha Hol

2. Contents • Introduction • Approach • Methods • Conclusions • Discussion

3. Introduction • Haematological malignancies -> Stem Cell Transplantation -> Complication: Graft versus Host Disease

4. Role of donor T-cells in SCT

5. Treatment of GvHD • Immunosuppressive drugs • Suicide gene therapy: • HSV-thymidine kinase with ganciclovir

6. Suicide gene therapy: CD20/αCD20 • Transduce T-cells with CD20-gene • Transplant • T-cell depleted Hematopoeitic Stem Cells • CD20 T-cells • GvHD -> αCD20 = Rituximab

7. Suicide gene therapy: CD20/αCD20 Rituximab (CD20 antibody) + complement

8. FACS SS SS FS FS Side Scatter (SSC) Side Scatter (SSC) Forward Scatter (FSC) Forward Scatter (FSC)

9. Approach • Transfect Ph-ampho cells to produce virus with CD20 vector • Transduce CD20 DNA to human CEM cells • Examine the expression of CD20 • Examine the effect of Rituximab on transduced cells

11. Transfection • Ph-ampho cells for virus production • Gene variants: • CD20 • CD20 wpre ic • CD20 wpre • CD20 ins9

12. Transfection • CD20, CD20 wpre ic and CD20 wpre transfected • CD20 ins9 not expressed • Virus harvested

14. Transduction • CEM cells (human donor T cells) • Incubated with 4 virus concentrations • Examined CD20 expression (transduction efficiency)

15. Transduction • CD20 expression in transduced T cells

16. Transduction

17. Effect of Rituximab Rituximab (CD20 antibody) + complement

18. Effect of Rituximab Clones Control

19. Conclusions • CD20 T-cell production possible • Rituximab causes cell lysis -> independent of level of CD20 expression

20. Discussion • No reliable negative control • Up to 10% CD20 T-cell survival • Rituximab specific for CD20 (?) • CD20 on human B-cells