Hematopoietic diseases
One of the branches of the group Experimental Medicine and Immunotherapy is the development of immunotherapeutic strategies against hematologic diseases.
The maturation of blood cells (hematopoiesis) starts from common precursor cells, called stem cells, irrespective of future cell function. The differentiation takes place within the red bone marrow and party within the lymphatic system. Once the cells are fully functional, they get released into the blood stream.
If this complex process gets distorted, blood cells can become abnormal with uncontrolled proliferation. This leads to various diseases and symptoms based on the affected cell type. In every case however, the targeted killing of abnormal cells is of utmost importance. Conventional therapies (chemotherapy and/or cytostatic drugs) are not able to distinguish between healthy blood cells and affected, malignant tumor cells. Side effects such as nausea, fatigue and systemic disorders in hematopoiesis and hemo-clearance occur. New, innovative approaches (eg. antibody-mediated therapies) are able to directly act specifically at the very cause of the sickness. This is one of the core expertise of the EMI-group: The development immunotherapeutic strategies for different diseases.
Phage-Display method
To select highly specific antibodies the Phage-Display method is applied. It is based on a library consisting of monoclonal antibody fragments, which are generated artificially or isolated from donated plasma cells and are presented on the surface of bacteriophages. During multiple rounds of selection (biopanning) only phage antibodies that specifically bind the desired, provided antigen are isolated.
Our group has developed different selection strategies, using multiple panning approaches and varying antigen formats. The following table gives a short overview:
Selection… | Antigen format: | Panning strategy: |
… highly specific binder | Membrane fragments, viable cells, purified protein | Reduction of concentration of provided antigen |
… high affinity binder | Membrane fragments, viable cells, purified protein | Increase of washing stringency |
… internalizing binder | Viable cells | Selection with varying temperatures (4°C → 37°C) |
Our group has access to multiple Phage-Display libraries:
- The semi-synthetic, naïve scFv-phage library Tomlinson I and J
(MRC Center for Protein Engineering, Cambridge, UK)
- The naïve scFv-phage library HAL7/8
(Group of Stefan Dübel, TU Braunschweig, Germany)
All libraries are based on conserved, human frameworks, which facilitates future clinical use in humans.
Functionalized antibody derivatives
Based on the desired diagnostic and/or therapeutic use, the selected antibody derivatives can be functionalized. First, the scFv-antibodies are characterized in vitro with respect to their biological properties. Then, their binding domain is genetically fused with different fusion partners. Fusion partners at hand include:
- Fc-parts of antibodies from different species
- Different dyes
- Components of toxins like DAPK-2 and ETA
This allows for vastly flexible use of the recombinant antibody derivatives.
