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To study immunobiological processes isolated from the in vivo situation, we established the culture of different cell types. The following pictures demonstrate a brief overview.
Cell culture lab: We are working with human and mouse adult and embryonic stem cells as well as cardiomyocytes, airway cells, lymphocytes, endothelial and smooth muscle cells, and fibroblasts.
Embroid bodies generated from embryonic stem cells.
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From left to right: Human cardiomyocytes, human airway cells in vitro and after processing (H+E staining). We are shipping our cells to collaboration labs worldwide.
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We are using state-of-the-art embedding protocols, which allow us to perfrom immunohistochemistry on almost all paraffin sections. 
Histology lab. Christiane Pahrmann is working on the cryostat.
The upper photomicrographs depict representative mid-graft cross sections 5 days after heterotopic heart transplantation for the groups investigated (R348= JAK3 inhibitor; rapamycin= mTOR inhibitor). Histologic sections stained with H&E (original magnification ×200) were used to assess acute rejection. Immunostaining on ED1 and CD3 (original magnification ×400) was performed to assess cell densities of macrophages and lymphocytes, respectively.
Cross sections of mouse heart after myocardial infarction (LAD ligation) (trichrome staining). Hearts after transplantation of genetically modified mesenchymal stem cells (MSC-HGF and MSC-VEGF) showed significant less scar extend.
We are investigating the mechanisms of acute and chronic rejection, the interaction of different cells types in the rejection process and involved pathways using techniques like ELISPOT, FACS, ELISA, western blotting, dot blot arrays, and Immuknow assays.
The following pictures are demonstrating some of our established techniques:
Western blot. Example for IkB in the cytoplasm of airway cells (with and without IL1beta stimulation).
Complement activation assay.
ELISPOT. We are using ELISPOTS to identify Th1 cells, Th2 cells, and Th17 cells. 
Membran array.
Flow cytometry. We are using FACS to investigate surface molecule expression and cell characterization, as well as to measure donor-specific antibodies.
Migration, invasion, and proliferation assays are used to characterize the cell performance in vitro.
Welcome to our microsurgery lab. We are performing LAD ligations, heterotopic heart transplantations, orthotopic and heterotopic trachea transplantations, skin transplantations, orthotopic aortic transplantations, bone marrow and lung transplantations, stent implantations and aortic injury techniques in mice and rats.
From left to right: Stem cells are isolated and transferred into a cell culture dish to expand the cells and purify them.
Heart after LAD ligation. Orthotopic trachea transplantation.
Our lab is equipped with state-of-the-art technology like Bioluminescence Imaging (BLI) and OCT.
BLI
BLI requires genetic engineering of the cells or tissues to image with a reporter gene that encodes for a light-generating enzyme (luciferase).
How does it work?
Typically a gene encoding for an enzyme such as luciferase, is inserted into tissues of the animal model of interest. Cells expressing the gene are allowed to grow for the desired period of time. A substrate for the enzyme (eg. luciferin) is then administered to the animal. The reaction between the enzyme and substrate results in emission of light by the cells expressing the luceriferase. This light is imaged by the IVIS device- essentially a very sensitive CCD camera.
Because mammalian tissues do not naturally emit bioluminescence, the advantage of in vivo BLI is the inherently low background signal.
The firefly luciferase enzyme converts the substrate D-luciferin to oxyluciferin, resulting in green light emission at 562nm.
What can it be used for?
Essentially to monitor gene expression in vivo. The most simple applications use the luciferase expression as a marker of cell viability. If, for example, expression is limited to stem cells growing in the animal, the cell survival and migration after transplantation can be determined by measuring the amount of bioluminescence produced. If used as part of a multi-cistronic vector, then the signal can be used to monitor the function of control elements or other genes in the construct.
Molecular imaging has proven a reliable methodology for tracking the long-term fate of transplanted cells. Therefore, molecular imaging is expected to play an increasing role in characterizing the biology and physiology stem cells in living subjects.
Stable ex-vivo transduction of adult stem cells to express firefly luciferase. Fluc expression correlates with cell number. 
In vivo monitoring of stem cell migration: After IV injection, adult mesenchymal stem cells are trapped within the lung capillaries.
Sonja Schrepfer and Tobias Deuse with the IVIS 200 system (Xenogen)
Available imaging techniques:
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Left: MicroCTs from mouse hearts after LAD ligation (left row) and after LAD ligation plus stem cell transplantation (right row).
Right: the upper picture shows an implanted human coronary stent into the abdominal rat aorta. Lower picture: In vivo monitoring of in stent restenosis using OCTs.
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