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Heisenberg-Grant - Intravital microscopy to investigate the function and motility of leukocytes during autoimmune processes in the CNS

  • Project Leader: PD Dr. Naoto Kawakami
  • Affiliation: Institute of Clinical Neuroimmunology
  • Funding: since 2014

We use an in vivo microscopy approach to better understand the molecular and cellular mechanisms of the infiltration of autoreactive t cells into the brain. In this context, we are working on the following research projects:

Highly and weakly encephalitogenic T cells

The encephalitogenicity of T cells depends on TCR specificity and host. We have shown previously that the encephalitogenic potential is also related to T cell activation in the CNS. Highly encephalitogenic T cells were activated in the CNS, whereas weakly encephalitogenic T cells were not. However, it is largely unknown what factors contribute to different degree of T cell activation. We visualized and compared the behaviour of highly and weakly encephalitogenic T cells in the animal. We are especially interested in differences in antigen presentation within the CNS.

Visualizing T cell activation in vivo

Varying calcium concentrations within a migrating T cell were detected using a FRET-based calcium biosensor. Image was acquired by intravital two-photon microscopy. Encephalitogenic T cells are activated in the CNS; however, the percentage of activated T cells goes only up to 40%. By conventional immunological analysis, it is hard to answer where and how T cells are activated within the target organ. In contrast, by using a recently developed calcium sensing protein, we can visualize T cell activation in vivo at single cell level. To this end, we express Fluorescence Resonance Energy Transfer (FRET) based calcium sensing protein in T cells and use them for intravital two-photon imaging.
Collaborators: Oliver Griesbeck (MPI Neurobiology)

Imaging in mouse EAE models

Interaction of regulatory T cells (green) with effector T cells (red) and antigen presenting cells (APC, grey) in the spinal cord of a mouse with experimental autoimmune enzephalomyelitis (EAE). The autoreactive T cells infiltrate into the CNS and cause inflammation. It was suggested that regulatory T cells have suppressive function in this process; however its mechanism remains unclear. In this project, we used differently labelled regulatory T cells and effector T cells in the mouse active and spontaneous EAE model (Link to Guru’s page). Additionally, antigen presenting cells are fluorescently labelled as well. By analysing interaction between regulatory/effector T cells/antigen presenting cells, we explore the suppression mechanisms of regulatory T cells, especially in brain and spinal cord.
Collaborators: Gurumoorthy Krishnamoorthy (MPI Neurobiology)

Source: RG Kawakami