Fraunhofer Institute for Cell Therapy and Immunology IZI 3 articles published in JoVE Bioengineering DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers Jörg Schnauß*1,2, Martin Glaser*1,2, Jessica S. Lorenz1, Carsten Schuldt1,2, Christin Möser1, Martin Sajfutdinow1, Tina Händler1,2, Josef A. Käs2, David M. Smith1 1Fraunhofer Institute for Cell Therapy and Immunology, 2Institute of Experimental Physics I, Universität Leipzig Semiflexible polymers display unique mechanical properties that are extensively applied by living systems. However, systematic studies on biopolymers are limited since properties such as polymer rigidity are inaccessible. This manuscript describes how this limitation is circumvented by programmable DNA nanotubes, enabling experimental studies on the impact of filament rigidity. Immunology and Infection Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples Jörg Flemmig1, Pauline Schwarz1, Ingo Bäcker2, Anna Leichsenring2, Franziska Lange2, Jürgen Arnhold1 1Institute for Medical Physics and Biophysics, Medical Faculty, University of Leipzig, 2Fraunhofer Institute for Cell Therapy and Immunology (IZI) Leipzig This protocol describes the quick enrichment of leukocytes from small blood samples for a subsequent specific determination of the halogenating peroxidase activity within the cells. The method can be applied to human and non-human material and may contribute to the evaluation of new inflammatory markers. Immunology and Infection Isolation and Flow Cytometric Analysis of Immune Cells from the Ischemic Mouse Brain Claudia Pösel*1, Karoline Möller*1, Johannes Boltze1,2, Daniel-Christoph Wagner1, Gesa Weise1,3 1Ischemia Research Unit, Fraunhofer Institute for Cell Therapy and Immunology, 2Fraunhofer Research Institution for Marine Biotechnology, University of Lubeck, 3Department of Neurology, University of Leipzig Inflammation plays a central role in the pathogenesis of ischemic stroke. Increasing evidence suggests that it acts as a double-edged sword which exacerbates early brain injury, but also contributes to later repair. This protocol describes the isolation of immune cells from the ischemic brain and their subsequent flow cytometric phenotyping.