Abstract
The effects of T cell factors, including interleukin (IL)-3 and IL-4, and fibroblasts on the growth and differentiation of human lung mast cells (MCs) obtained by bronchoalveolar lavage (BAL) were examined. The numberof MCsidentified by alcian blue-safranin staining was twice that of the control culture without conditioned medium (CM) when BALcells were cultured for 2 weeks in RPMI 1640 containing 10% fetal calf serum and partially purified CMderived from PHA-stimulated lymphocytes.
In the presence of both recombinant (r) IL-3 and rIL-4, the number of MCswas twice as high as the control without increase in the per-cell histamine content after 2 weeks' culture. In umbilical cord blood cultures, IL-3 plus IL-4 augmented basophilic cells about 20-fold more than the control when cultured for 2 weeks. In some cases, the percentage of safranin-positive MCswas about 2-5 fold greater, with 2-7 fold higher histamine content, when cultured for 10 days with CMand fibroblasts derived from human embryonic lung. However, in all BALexperiments, there was no increase in the total numberof MCsafter culture compared with the initial number of MCs, unlike the umbilical cord blood cultures. These results suggest that T cell factors, including IL-3 and IL-4, and fibroblasts may influence the phenotype and the survival of lung mast cells in BAL, whereas there was no evidence for the presence of MCprecursors in BALfluids.
