Research at the Molecular T cell Immunology investigates the cross-talk of T-cell subsets with the blood coagulation system.

We previously demonstrated that activation of coagulation factor XII to trigger the contact activation pathway by platelet-derived polyphosphate (polyP) is regulated by XPR1 (xenotropic and polytropic retroviral receptor 1). Moreover, recent data showed that CD4+ T cells are rich in polyP that contributes to FXII-dependent coagulation in vitro and in vivo.

We aim to elucidate the role of polyP for stimulation, proliferation and differentiation of CD4+ T cells with membrane-permeable polyphosphatase using confocal microscopy and FACS analysis. T cell-mediated blood clotting is investigated via chromogenic assays, endogenous thrombin potential and mechanical ball coagulometer experiments in vitro and via thrombosis models using wildtype and FXII knockout mice in vivo. In addition, we analyze antigen-specific T-cell responses in XPR1 deficient mice using gene expression profiling and the detailed analysis of T-cell stimulation pathways. Our current research also includes translational approaches to better understand the contribution of T cells in polyP-driven thrombosis in patients with autoimmune diseases, chronic inflammation or leukemia. Taken together, we study novel strategies to regulate T cell-mediated immune responses and thrombotic diseases via polyP.