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Startseite > Forschung > Arbeitsgruppen > Arbeitsgruppe Prof. Dr. rer. nat. Petra Bacher > english version Bacher

Research Group Prof. Dr. rer. nat. Petra Bacher



Intestinal Immune



We are investigating the role of T-helper (Th) cells in immune-mediated diseases. Using novel approaches for the direct analysis of antigen-reactive Th cells, we try to understand why tolerance mechanisms of the immune system fail in patients with chronic inflammatory diseases.



Immune tolerance, Antigen-specific T cells, Inflammatory bowel diseases, Commensal microbiota, Immunogenetics, Allergy, Regulatory T cells


Group members

  • group leader: Prof. Dr. rer. nat. Petra Bacher
  • students:

    Gabriela Rios Martini (PhD student)

    Ann-Kristin Kamps (PhD student)

    Stephan Schneiders (PhD student)

    Anna Schiffer (MD student)

    Veronica Chaves Vargas (master student)

  • technicial assistance:

    Berith Messner


Scientific Profile


Our main focus is the role of antigen-specific Th cells in human immune responses. T helper (Th) cells are central organizers of immune responses. Via their T cell receptor, they are able to recognize a specific antigen. By releasing different effector cytokines, they can initiate a immune response appropriate to the antigen. However, inappropriate or too strong immune reactions can lead to immune pathologies, such autoimmunity, chronic inflammation or allergies. A specialized Th cell subpopulation, the regulatory T cells (Tregs) on the other hand, have suppressive properties. This enables them to dampen or even prevent the immune response against a certain antigen.

However, which T cells react against a particular antigen, which antigens are at all recognized and how protective immunity and tolerance is maintained or disrupted is in many clinically situations not known. Using novel approaches to analyze antigen-reactive Th cells directly ex vivo from human samples, we are conducting studies to understand why in patients with chronic inflammatory diseases, such as inflammatory bowel disease or allergies, tolerance mechanisms fail. Antigen-reactive Th cell analysis can be combined with powerful state-of-the-art analytical technologies, such as multidimensional flow cytometry, (single cell) transcriptomics, TCR sequencing and proteomics, to provide single cell information at high resolution. We aim to elucidate the interaction between environmental factors and microbial and inflammatory processes that lead to dysfunctions and inflammation. The analysis of these fundamental processes directly in cells from the human immune system will significantly advance our understanding of basic mechanisms underlying human immune-mediated diseases and speed up the development of new diagnostic as well as therapeutic strategies for chronic inflammatory diseases, autoimmunity or allergy.


List of scientific projects

  • Human T cell responses against intestinal microbiota
  • Characterization of food-reactive T cells
  • Antigen-specific CD4+ T cells as specific diagnostic sensors in cystic fibrosis patients
  • Functional and molecular characterization of human Th17 subsets


Selected publications

1. Low avidity CD4+ T cell responses to SARS-CoV-2 in unexposed individuals and humans with severe COVID-19

Bacher P, Rosati E, Esser D, Rios-Martini G, Saggau C, Schiminsky E, Dargvainiene J, Schöder I, Wieters I, Khodamoradi Y, Eberhardt F, Vehreschild MJGT, Neb H, Sonntagbauer M, Conrad C, Tran F, Rosenstiel P, Markewitz R, Wandinger, K-P, Augustin M, Rybniker J, Kochanek M, Leypoldt F, Cornely OA, Koehler P, Franke A, Scheffold A. Immunity 2020, doi:

2. Human Anti-fungal Th17 Immunity and Pathology Rely on Cross-Reactivity against Candida albicans

Bacher P, Hohnstein T, Beerbaum E, Röcker M, Blango MG, Kaufmann S, Röhmel J, Eschenhagen P, Grehn C, Seidel K, Rickerts V, Lozza L, Stervbo U, Nienen M, Babel N, Milleck J, Assenmacher M, Cornely OA, Ziegler M, Wisplinghoff H, Heine G, Worm M, Siegmund B, Maul J, Creutz P, Tabeling C, Ruwwe-Glösenkamp C, Sander LE, Knosalla C, Brunke S, Hube B, Kniemeyer O, Brakhage AA, Schwarz C, Scheffold A. Cell. 2019; 176(6):1340-1355.e15. 

3. Regulatory T Cell Specificity Directs Tolerance versus Allergy against Aeroantigens in Humans

Bacher P, Heinrich F, Stervbo U, Nienen M, Vahldieck M, Iwert C, Vogt K, Kollet J, Babel N, Sawitzki B, Schwarz C, Bereswill S, Heimesaat MM, Heine G, Gadermaier G, Asam C, Assenmacher M, Kniemeyer O, Brakhage AA, Ferreira F, Wallner M, Worm M, Scheffold A. Cell. 2016 167(4):1067-1078. 

4. Fungus-specific CD4+ T cells for rapid identification of invasive pulmonary mold infection

Bacher P, Steinbach A, Kniemeyer O, Hamprecht A, Assenmacher M, Vehreschild MJGT, Vehreschild JJ, Brakhage AA, Cornely OA, Scheffold A. Am J Respir Crit Care Med. (2015) 191(3):348-52. 

5. Antigen-specific expansion of human regulatory T cells as a major tolerance mechanism against mucosal fungi

Bacher P, Kniemeyer O, SchoenbrunnA, SawitzkiB, Assenmacher M, Rietschel E, Steinbach A, Cornely OA, Brakhage AA, ThielA, ScheffoldA. Mucosal Immunology. (2014) Jul;7(4):916-28.



 Third party funding

  • ECCO Grant 2019: The immune repertoire of microbe-reactive T cells in blood and tissue of IBD patients
  • Christiane Herzog Foundation 2016-2018: Antigen-specific CD4+ T cells as specific diagnostic sensors for high-resolution pathogen diagnostics in CF patients


List of cooperation partners in alphabetical order

  • Dr. Mario Assenmacher, Marco Vahldieck, Jennifer Pankratz; Miltenyi Biotec GmbH, Bergisch Gladbach, Germany
  • Prof. Nina Babel, Dr. Ulrik Stervbo; Marien Hospital Herne, Universitätsklinikum der Ruhr-Universität Bochum, Germany
  • Prof. Axel Brakhage, Dr. Olaf Kniemeyer; Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie (HKI), Jena, Germany
  • Prof. Oliver Cornely, Angela Steinbach; Klinik I für Innere Medizin, Uniklinik Köln, Köln, Germany
  • Prof. Andre Franke, Elisa Rosati; Institut für Klinische Molekularbiologie, CAU Kiel, Germany
  • Prof. Bernhard Hube, Dr. Sascha Brunke; Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie (HKI), Jena, Germany
  • Dr. Jochen Maul, Medizinische Klinik für Gastroenterologie, Infektiologie und Rheumatologie CBF, Charité – Universitätsmedizin Berlin, Berlin, Germany
  • Prof. Birgit Sawitzki, Katrin Vogt; Berlin-Brandenburg Center for Regenerative Therapies, Charité - University Medicine Berlin, Germany
  • Prof. Alexander Scheffold; Institut für Immunologie, CAU Kiel, Germany
  • Dr. Carsten Schwarz, Svenja Kaufmann, Jobst Röhmel; Klinik für Pädiatrie m.S. Pneumologie und Immunologie, Charité – Universitätsmedizin Berlin, Berlin, Germany
  • Prof. Margitta Worm, Dr. Guido Heine, Klinik für Dermatologie, Venerologie und Allergologie, Charité – Universitätsmedizin Berlin, Berlin, Germany