MAST-CELL HETEROGENEITY IN THE GASTROINTESTINAL-TRACT - VARIABLE EXPRESSION OF MOUSE MAST-CELL PROTEASE-1 (MMCP-1) IN INTRAEPITHELIAL MUCOSAL MAST-CELLS IN NEMATODE-INFECTED AND NORMAL BALB C MICE/

Soluble granule chymases in rodent intestinal mucosal mast cells (IMMC s) may play an important role in altering epithelial permeability duri ng immediate hypersensitivity reactions. Using a monoclonal antibody a gainst the chymase mouse mast cell protease-1 (mMCP-1), we have shown that it is constitutively expressed in less than or equal to 20% of es terase-positive (esterase(+)) IMMCs but not in esterase(+) gastric muc osal mast cells (GMMCs) in normal BALB/c mice. Intestinal infection wi th mouse- or rat-adapted strains of Nippostrongylus brasiliensis resul ted in IMMC hyperplasia with 100% of esterase(+) IMMCs expressing mMCP -1. In contrast, there was a variable response in terms of numbers of GMMCs and of the proportion expression mMCP-1. Esterase(+) mast cells in the gastric submucosa, muscularis, ear pinna, lung parenchyma, majo r airway submucosa, and peritoneal cavity did not express mMCP-1. The few airway esterase(+) mast cells expressing mMCP-1 were, like the gre at majority of IMMCs and GMMCs, located intraepithelially. In conclusi on, mMCP-1 is predominantly expressed by intraepithalial mucosal mast cells but not in all sites; the immunological stimulus associated with intestinal nematodiasis substantially up-regulates mMCP-1 expression by mast cells in the jejunum but not in the stomach; IMMCs and GMMCs i n BALB/c mice are phenotypically and possibly functionally distinct.