Apparent innervation of rat basophilic leukaemia (RBL-2H3) cells by sympathetic neurons in vitro.

Association of mast cells (MCs) and nerves may represent communication between the immune and nervous systems. The morphological features of associations between sympathetic neurons and rat basophilic leukaemia cells (RBL), a model for the mucosal mast cell, were studied in a tissue culture model. Initially, neuronal growth cones contacted single RBL with large areas of membrane apposition. With time, these appeared as distinct zones of contact where intervening distances were less than or equal to 50 nm. Large dense-cored granules suggested localization of peptidergic neurotransmitters. Encircling of neurite profiles by RBL resembled intimate nerve-MC relationships in vivo. These modifications may serve to optimize the area of interaction.