Co-culture of human lung-derived mast cells with mouse 3T3 fibroblasts: Morphology and IgE-mediated release of histamine, prostaglandin D sub(2), and leukotrienes

Human mast cells, dispersed from lung tissue by proteolytic treatment and enriched to a purity of 23 to 68% by density-gradient centrifugation, were maintained ex vivo for up to 13 days when co-cultured with mouse skin-derived 3T3 fibroblasts in RPMI 1640 containing 10% fetal calf serum. The human mast cells were adherent to the fibroblast cultures within 2 to 4 hr after seeding, and after 7 days of co-culture were localized between the layers of fibroblasts. When freshly isolated mast cells were activated immunologically, they exocytosed 38 plus or minus 8% of their total histamine content and released 28 plus or minus 1.9 ng of immunoreactive equivalents of prostaglandin D sub(2) (PGD sub(2)) per mu g of total cellular histamine, but did not generate significant amounts of either leukotriene C sub(4) (LTC sub(4)) or leukotriene B sub(4) (LTB sub(4)). Thus, human lung-derived mast cells can be maintained ex vivo when co-cultured with fibroblasts, and, when treated with anti-IgE, they metabolize arachidonic acid via both the cyclooxygenase and the 5-lipoxygenase pathways.