Tracking down the tiniest of forces: how T cells detect invaders

1/2 images 1 of 2 images or videos - T cells use their antigen receptors like sticky fingers - a team from TU Wien and MedUni Vienna was able to observe them doing so. T-cells play a central role in our immune system: by means of their so-called T-cell receptors (TCR) they make out dangerous invaders or cancer cells in the body and then trigger an immune reaction. On a molecular level, this recognition process is still not sufficiently understood. Intriguing observations have now been made by an interdisciplinary Viennese team of immunologists, biochemists and biophysicists. In a joint project funded by the Vienna Science and Technology Fund and the FWF, they investigated which mechanical processes take place when an antigen is recognized: As T cells move their TCRs pull on the antigen with a tiny force - about five pico-newtons (5 x 10-12 or 0.0000000005 newtons). This is not only sufficient to break the bonds between the TCRs and the antigen, it also helps T cells to find out whether they are interacting indeed with the antigen they are looking for. These results have now been published in the scientific journal "Nature Communications".