Lay summary

Lymphocyte trafficking and activation


. Within these organs, lymphocytes screen antigen-presenting cells for their cognate antigen. Recirculation is completed by migration of lymphocytes back to blood via lymphatic vessels. Continuous trafficking makes lymphocytes one of the most motile mammalian cell types, migrating hundreds of micrometer every day within tissue.spleen and lymph nodes through the body in search of foreign antigen. Lymphocytes are in permanent movement from blood into lymphoid organs such as continuous lymphocyte traffickingAn essential feature of the adaptive immune system is the


Chemokines are small secreted polypeptides highly expressed in spleen and lymph nodes and play an important role in the selective recruitment of blood-borne lymphocytes into lymphoid tissue. Also, chemokines are responsible for lymphocyte segregation into T and B cell areas inside lymphoid tissue. As an example, the chemokine CCL21 is highly expressed in the T cell area of lymph nodes, as well as on high endothelial venules (HEV), which serve as port of entry for circulating lymphocytes. CCL21 is a strong chemoattractant for naïve T cells and serves therefore as a central organizing molecule for lymphoid organs.chemokine receptors. Lymphocyte trafficking is a finely tuned mechanism, which is in large part regulated by adhesion receptors of the integrin family and G-protein-coupled receptor (GPCR), notably


Our research group works on three complementary lines of investigation:


, with a special emphasis on intracellular chemokine receptor signaling (small GTPases and their activators, etc) and the roles of adhesion molecules and stromal cells in this process;molecular mechanisms of lymphocyte migration to and within lymph nodes1. A major focus is the study of


during immune responses using transgenic lymphocytes lacking of one or more signaling or adhesion molecules; T cell-dendritic cell (DC) interactions2. We are examining


. With OPT, we are performing mesoscopic imaging of the internal 3D structure of lymph nodes during homeostasis and inflammation.optical projection tomography (OPT) and intravital microscopy, (IVM), multiplex twophoton microscopy (2PM) for a quantitative analysis of adaptive immune responses, mainly imaging techniques3. We are applying novel

.in vivoIn summary, we are combining cutting-edge microscopy and complementary techniques with transgenic models to examine the migratory and activation behavior of lymphocytes