Figure 2. Cellular communication by mast cells promotes host defence.

Mast cells ‘communicate’ with various cell types, including immune cells (such as lymphocytes^50,67,71, macrophages⁵¹, dendritic cells^{41,46,49,61,68–70} and neutrophils^{34,35,43,44,48,52}), epithelial cells⁶⁶, smooth muscle cells^45,63 and endothelial cells^49,57–60. These interactions contribute to pathogen surveillance, antipathogen immunity and other mechanisms of eliminating microorganisms from the host. These cellular targets of mast cells are located both in the site of infection and in distant draining lymph nodes. Examples of functional consequences of mast cell communication are shown, as are examples of mast cell mediators that have been shown to contribute to the target cell response. BCR, B cell receptor; CCL5, CC-chemokine ligand 5; IL, interleukin; LT, leukotriene; MCP1, mast cell protease 1; PG, prostaglandin; TCR, T cell receptor; TNF, tumour necrosis factor.