The ultrastructure of mucosal mast cells.

The two mast cell populations in the rat small intestine, mucosal mast cells (from the lamina propria) and connective tissue mast cells (from the submucosa), have differing staining characteristics. Differential staining techniques have also shown that these two mast cell populations exist widely in the rat, human and macaque monkey. Mucosal mast cells obtained from the rat ileum, the human jejunum (biopsy) and the macaque lung (by bronchoalveolar lavage) were examined by electron microscopy in an attempt to characterize this type of mast cell by its ultrastructural features. Although no common feature typified the cells from these three species, a number of individual features within each species were noted.