Neuropilin-1 in the immune system.

The neuropilin-1 (NRP1) and neuropilin-2 (NRP2) receptors can bind the class 3 semaphorin subfamily and the heparin-binding forms of vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF). The functions of NRP1 and NRP2 have been extensively studied in neurons where they act in axon guidance and in endothelial cells where they promote angiogenesis and cell migration. In this chapter, we will present evidences indicating that neuropilin-1 is likely to mediate contacts between the dendritic cells and the T lymphocytes via homotypic interactions and is essential for the initiation of the primary immune response. These results emphasize the molecular similarities between the nervous and the immune systems and open new areas in the modulation of the immune response.