Research rendezvous: Sofia Johansson
Could you tell us a little about your research background?
I did my Biology degree at Stockholm’s University and my PhD at MTC on NK cell biology and NK cell regulation. I have worked as a Post Doc for Eric Vivier at CIML (Centre d'Immunologie de Marseille-Luminy) in Marseilles, France and later in KTH (with Jerker Widengren at Applied Biophysics) developing methods to look at the molecular dynamics (or how molecules move) and how fluorescence is effected by the surrounding environment. This information can be used to draw conclusions about oxygen concentration around the molecules, for example. I have been here at MTC for the past four years in a forskarassistent (Assistant Professor) position
Could you describe you current research project at MTC?
I have developed my own line of research focusing on the molecular dynamics of NK cell regulation. NK cells can be primed to react. We are interested in seeing how the molecular dynamics differ between “primed”, more active, and idle NK cells. Hopefully, this information can be used to predict how the NK cells will react when they reach the target cell that they are supposed to kill.
We are interested in molecular dynamics. We want to characterize the NK cells phenotypically in respect to how receptors move on the surface of NK cells. These receptors are used to get signals from surrounding cells, both inhibitory and activating. Ultimately we want to use this phenotype to understand how the cells are regulated and discover the underlying mechanisms.
We have two approaches, one where we look at how molecules move on the surface of NK cells and the other approach is to look at where these molecules are localized. To localize the molecules we use super solution microscopy (STED) and we look at how receptors cluster on the cell surface. To study dynamics or molecular movement we use two approaches. The first method I learned while at KTH and is called Fluorescence correlation spectroscopy. With this technique you look at a single point on the cell surface and how the molecules move through it. The second method is image based, using a microscope to make ‘maps’ of fluorescence intensity created over time to see how molecules have moved over time. This then involves a lot of mathematical modeling to extract information about how the movement of molecules has occurred.
We also have two different systems to look at different states of NK cell activity . One is cytokine activation of NK cells, which is a very potent activation. The other is that some NK cells can react to a lack of self MHC class I which is called ”missing self”. This is something that not all NK cells can do, only those who express the right receptors are “potentiated” or educated as we call it. Those that can react to missing self are the most active kind.
What are your plans for the future?
Our immediate future goal is to couple these phenotypical differences to a function – which could be for example adding inhibitors to break NK cell behaviour so they don’t kill anymore.
Does being at MTC affect your ability to achieve your goals as a researcher?
Yes it does, we have a lot of resources at MTC including Flow Cytometry, Microscopy and cell sorting and the proximity to SciLife is very convenient. In addition the administrative support at MTC is great.