Mast cell and mast cell granule phenotypes in normal and Nippostrongylus-infected rats. A qualitative laser confocal microscopic study.

In the rat, the individual mast cell secretory granules may be divided into three subpopulations based on the presence of the specific proteases RMCP-1, RMCP-2, or a variable combination of these two proteases. Mast cells in the tongue only express RMCP-1, both in normal and infected animals, whereas in the other tissue locations studied (lung, intestinal mucosa and submucosa, tracheal epithelium and submucosa) the mast cells contain all three granule subtypes in a wide variation of combinations. These studies demonstrate that there is wide heterogeneity in protease expression in rat mast cells, which may be influenced by local stimulation with environmental tissue factors.