Nele Philippens

Imaging and manipulation of the immunological synapse
Started on October, 2020

email Nele Philippens

Recently, immunotherapy has become a very promising approach to treat diseases like cancer. One such therapy exploits antigen presenting cells (APCs) to stimulate tumor specific T-cell responses. However, routine application of this strategy is hampered because the generation of these cells is costly and time demanding. For this reason, artificial antigen presenting cells (aAPCs) were developed as an off the shelf product. These structures mimic the function of the natural APCs but are more readily available. In collaboration with the Figdor group from the RadboudUMC (Nijmegen, NL) we are currently studying a new type of filamentous shaped aAPC, based on polyisocyanopeptides (PICs). These long (100-500 nm) helical shaped polymers have shown to be very potent activators of immune cells when decorated with T-cell stimulating antibodies. Compared to “standard” bead like aAPCs, the PICs induce more and better T-cell activation. Unfortunately, it is not known why these polymers induce such a potent response. During the natural interaction of APCs with T-cells, rearrangements of receptor microclusters have been demonstrated to play a crucial role to initiate downstream signalling. In this project, we will use PIC-based aAPCs to study receptor movements in 3-D and on live cells, using single molecule based super-resolution fluorescence microscopy. We expect this will unveil why PICs are such potent activators of T-cells and if the triggered receptor microclusters follow the classical rearrangements. The main goal of this project is to study how filamentous or “standard” bead like aAPCs effect receptor clustering on T-cells, ultimately leading to manipulation of the immunoresponse. 
To visualize the receptor movement on the T-cell membrane, the T-cell receptor and costimulatory receptors can be labelled with fluorescent fusion proteins. In addition  the PIC and bound antibodies can be labelled as well, to establish a full picture of polymer and receptor movements on the nanometre scale. The process will be imaged by state of the art super resolution fluorescent imaging techniques. In short this project will contain cloning techniques, bioconjugation of novel materials and imaging of biophysical processes.