Gut–neuroimmune interactions: the unexpected role of the immune system in brain development

of glial cell that ensheath neuronal axons to increase signal conductance. However, during different disease processes, these cells can initiate inflammation through microglia and disrupt normal neuronal signalling. Finally, mast cells can also prime the microglia in the brain. These immune cells release granules filled with histamine during normal development, which are recognized by the microglia. Glia, as well as neurons, can recognize specific pathogens through different toll-like receptors, which will initiate an immune response. Microglia have the most diverse expression of these receptors in the brain.