T-cell Antigen Recognition in Cancer and Autoimmunity

Prof. Dr. Johannes Huppa
 

 We focus on how the adaptive and innate branches of the immune system act in concert to differentiate friend from foe and malignant. Our research revolves around three principal questions:

  • How do T-cells recognize antigens at the cellular, subcellular, and molecular level?
  • What degree of cross-reactivity do T-cells exhibit when they scan a plethora of different peptide/MHC complexes with low affinity?
  • How does the structural degeneracy in T-cell antigen recognition affect immunity towards cancer and autoimmunity?
     
Quantification of TCR‐antigen binding within the immunological synapse via advanced microscopy A. Scheme of a FRET‐based assay to visualize TCR‐pMHCII interactions in situ between a T-cell and a planar supported lipid bilayer functionalized with antigen (here the peptide-loaded MHC class II protein I-Ek), the adhesion molecule ICAM-1 and the co-stimulatory molecule B7-1. The close proximity between the blue-shifted fluorophore Alexa Fluor 555 (AF555) and the red-shifted AF647, as it only occurs in the bound state, gives rise to precisely quantifiable Förster Resonance Energy Transfer (FRET). B. Microscopy-observed FRET resulting from 5c.c7 TCR‐transgenic T‐cells stained with H57 scFV‐AF555 and interacting with a planar glass-supported lipid bilayer featuring the antigen I‐Ek/MCC‐AF647. FRET yields were directly proportional to the TCR occupancy, the ratio of antigen bound TCRs to total TCRs. Scale bar, 5 μm. © Johannes Huppa, taken from Monomeric agonist peptide/MHCII complexes activate T-cells in an autonomous fashion. Platzer R., Hellmeier J., Göhring J., Doel-Perez I., Schatzlmaier P., Bodner C., Schütz G.J., Sevcsik E., Stockinger H., Brameshuber H., Huppa J.B.* (2023) EMBO Reports Sep 28:e57842. doi: 10.15252/embr.202357842

We aim for quantitative answers using a combination of cell biological, biophysical, genetic and omics- approaches. Our goal is to understand how T-cells arrive at their remarkable antigen selectivity and sensitivity, while maintaining a delicate balance between tolerance and immunity, which we deem critical for an effective anti-cancer response. We strive to harness gained insights to advance T-cell-based precision medicine in cancer and autoimmune diseases.

To achieve this, we engineer and utilize fluorescent probes and protein-functionalized planar supported lipid bilayers, enabling real-time observation of primary T-cells at work via advanced single-molecule live-cell imaging techniques. Moving forward, we aspire to integrate structural biology for enhanced spatial resolution as well as machine learning to comprehensively capture the complexities of membrane biophysics and systems biology associated with T-cell antigen recognition and T-cell immunity in cancer. 
 

Future projects and goals

  • We aim to uncover the mechanisms underlying the exceptional sensitivity of T-cell antigen detection, which render T-cells in principle highly effective against cancers with heterogeneous and dynamic antigen expression. To enhance spatial resolution, we will integrate advanced live-cell microscopy with structural biology, focusing particularly on CD4- and CD8-coreceptors, which engage MHC I and MHC II to amplify antigen detection up to 600-fold. 
  • Additionally, we seek to apply experimental and further develop predictive methods for TCR deorphanization to identify the target specificities of tumor-infiltrating lymphocytes. Following antigen matching, we will evaluate TCRs for sensitive antigen detection and derive engineered TCRs with improved ligand recognition for effective patient-specific TCR-T-cell therapies. 
  • Finally, we wish to contribute with our work to efforts aimed at predicting highly functional TCRs for any given cancer epitope.
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Prof. Dr. Johannes Huppa

Head of department – Institute of Immunology

Charité – Universitätsmedizin Berlin

T-Zell-Antigen-Erkennung bei Krebs und Autoimmunität / T-cell Antigen Recognition in Cancer and Autoimmunity

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Selected Publications

Research profile at Charité – Universitätsmedizin Berlin