Immortalization of murine connective tissue-type mast cells at multiple stages of their differentiation by coculture of splenocytes with fibroblasts that produce Kirsten sarcoma virus.
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Abstracto
Mature connective tissue mast cells (CTMC) have not been previously available as a cell line from any species. Here we describe 15 novel mast cell lines (KiSV-MC) that were derived by coculturing murine splenocytes with fibroblasts that produce a Ki-ras-containing murine sarcoma virus. Some of the KiSV-MC lines are similar to CTMC in that they synthesize predominantly heparin proteoglycans, and contain up to 35 micrograms of histamine and 2.2 units of carboxypeptidase A/10(6) cells in secretory granules which stain red with Safranin. Other cell lines display phenotypic characteristics intermediate to CTMC and mucosal-like mast cells in being predominantly Safranin-, having lower amounts of histamine and carboxypeptidase A, and in synthesizing chondroitin sulfate E proteoglycans in preference to heparin proteoglycans. When the individual KiSV-MC lines were compared, a linear relationship was found between the number of Safranin+ granules, the cellular contents of histamine and carboxypeptidase A, and the biosynthesis of heparin relative to chondroitin sulfate E proteoglycans. Upon sensitization with monoclonal IgE and exposure to hapten-specific antigen, the cells exocytose the contents of their secretory granules. Thus, these immortalized cells provide the first source of CTMC-like lines for chemical and functional analysis and illustrate that murine mast cells can express a continuum of phenotypes.