Mast Cells: Master Drivers of Immune Responses against Pathogens
Mast cells play a varied and tunable role in orchestrating immunity to pathogens. Prolonged interaction of mast cells with pathogens and their associated pathogen-associated molecular patterns (PAMPs), such as in a chronically inflamed tissue, could shape mast cell-directed immune responses. Mast cells secrete a wide variety of chemoattractants and cytokines that promote leukocyte trafficking to sites of infection, where they can contribute to pathogen clearance or amplify inflammation by secretion of proinflammatory cytokines. In a mouse model of dengue infection, mast cells upregulate the chemokines CX3CL1, CXCL12, and CCL5. This role of mast cells to recruit appropriate pathogen-clearing immune cells to sites of bacterial, viral, and parasitic infections is arguably the most important innate immune activity mediated by these immune surveillance cells. Mast cells are well known effectors of adaptive immunity by binding immunoglobulin through their Fc receptors. The best known instance of this is in IgE-mediated immunity against helminth parasites.
