Developing T-cell migration: role of semaphorins and ephrins

Abstract

Cell migration is a crucial event for nor mal T-cell development, and various ligand/receptor pairs have been implicated. Most of them, including chemokines and extracellular matrix proteins, have at tractant properties on thymocytes. We discuss herein two further groups of ligand/receptor pairs, semaphorins/ neuropilins and ephs/ephrins, which are constitutively expressed by thymocytes and thymic microenvironmental cells. Evidence shows that the corresponding interactions are relevant for developing T-cell migration, including the entry of bone marrow progenitor cells, migration of CD4/CD8-defined thymocyte subpopulations triggered by chemokines and/or extracellular matrix proteins, and thymocyte export. Conceptually, the data summarized here show that thymocyte migration results from a com plex network of molecular interactions, which generate not only attraction, but also repulsion of migrating T-cell precursors.—Mendes-da-Cruz, D. A., Stimamiglio, M. A., Muñoz, J. J., Alfaro, D., Terra-Granado, E., Garcia-Ceca, J., Alonso-Colmenar, L. M., Savino, W., Zapata, A. G. Develop ing T-cell migration: role of semaphorins and ephrins.