Christoph Klein, MD, PhD
Department of Pediatric Hematology, Oncology
Hematopoietic stem cell biology
Gene transfer technologies
Our interdisciplinary group, recently established at the MHH, is primarily interested to evaluate genetic engineering techniques in cells of the hematopoietic and immune system. We focus both on preclinical gene therapy studies and gene transfer related basic science issues.
- Evaluation of retroviral gene transfer techniques in human hematopoietic stem cells. We have previously shown that the specific T cell defect in WASP-deficient mice can be rescued upon transplantation of retrovirally transduced hematopoietic stem cells. In anticipation of a clinical trial we currently study WASP-gene transfer into human hematopoietic stem cells using retroviral and lentiviral vectors.
- Development of innovative techniques to induce site-directed genetic modifications in hematopoietic stem cells. The ideal form of gene therapy of monogenetic diseases is a targeted correction of the mutated gene.Although feasible, the extremely low frequency of recombination events still prevents therapeutic use of gene targeting. However, the frequency of homologous recombination is dramatically increased f a unique double strand break challenges the integrity of the genome. We are interested to utilize the cell's repair machinery to induce homologous recombination events at sites of specific DANN cleavage. For this purpose, various synthetic nucleases are currently being tested for their potential application to induce homologous recombination. This project is being realized in collaboration with Dr. André Choulika, Institut Pasteur, and Prof. Nils-Metzler-Nolte, University Heidelberg.
- Functional analysis of the Wiscott-Aldrich-Syndrome-Protein (WASP) Using WASP-deficient knock-out mice we study the function of WASP for the homeostasis of the immune system. Preliminary experiments suggest that the migration of lymphozytes, dendritic cells and granulozytes is severely impaired in the absence of WASP. We currently dissect the role of WASP in integrin-mediated signals in dendritic cells.
- Modulating the immune system using genetically modified dendritic cells. Our previous studies have shown that genetically modified dendritic cells are clearly superior to cytokine-transduced tumor cells in eradicating preexisting murine tumors. Furthermore, we successfully altered the in vivo trafficking pattern of dendritic cells by expressing a chimeric E/L-selectin and thus increased the efficacy of dendritic cells to induce an anti-tumor immune response. Now, we study the immunogenicity of leukemia cells in a mouse model and pursue our efforts to design a dendritic cell based vaccination approach for childhood leukemia.
Christoph Klein, MD, PhD Ricardo Dewey, PhD Christoph Happel, MD Parool Meelu, PhD student Chozhavendan Rathinam, PhD student Gesine Koene, PhD student Christian Pfeffer, MD student Astrid Fitter, technician
Generation and characterization of retroviral- and lentiviral vectors Gene transfer technologies Hematopoietic stem cell differentiation Animal models (stem cell transplantation, tumor models) Evaluation of the immune response Fluorescence microscopy
Klein C, Bueler H, Mulligan RC. Comparative analysis of genetically modified dendritic cells and cytokine-transduced tumor cells as therapeutic cancer vaccines. J Exp Med 191: 1699-1708 (2000)
Dahl AM, Klein C, Andres PG, London CA, Lodge MP, Mulligan RC, Abbas AK. Exprexxion of Bel-XL restores survival, but no proliferation and effector differentiation, in CD28-deficient T lymphozytes. J Exp Med 191: 2031-2038 (2000)