Comparative cytokine release from human monocytes, monocyte-derived immature mast cells, and a human mast cell line (HMC-1).

To obtain further information regarding the role of cytokines during mast cell differentiation, we have investigated changes of cytokine secretion in mast cells developing from the human peripheral blood monocytic cell fraction during culture with fibroblast-derived conditioned media. The influence of stem cell factor and an antibody to the respective receptor in our culture system was studied as well. Interleukin (IL)-1 alpha, IL-1 beta, IL-6, and tumor necrosis factor (TNF)alpha were spontaneously secreted by cultured cells at day 1 and decreased markedly by day 14. Similar changes occurred also during culture with stem cell factor and were partially abrogated by an anti-receptor antibody. IL-8 was secreted at a high level throughout the culture, whereas no spontaneous secretion of IL-2, IL-3, IL-4, and IL-7 was measured at all. Upon stimulation with phorbol myristate acetate and A23187, cultured cells showed substantially more release of IL-3 and TNF-alpha after 14 d of culture, compared to peripheral blood monocytic cells. Preformed TNF-alpha was found in one of three monocytic cell preparations from peripheral blood, but not in monocytic cell-derived mast cells. During mast cell differentiation, cytokines from monocytic cells are therefore downregulated while the cells assume a pattern typically found in mast cells.