Study of the favorable culture condition to produce granulocyte. Macrophage colony stimulating factor and interleukin-6 by human nasal epithelial cells

Abstract

Allergic rhinitis and nasal polyposis are upper airway inflammatory conditions characterized by increased numbers of eosinophils and metachromatic cells in the epithelial layer of the nasal mucosa. However, the mechanism by which these cells accumulate still remains obscure in many respects. It is suggested that the granulocyte-macrophage colony stimulating factor (GM-CSF) plays an important role in the nasal mucosa, since the supernatant of cultured epithelial cells induce differentiation of peripheral mononuclear cells into metachromatic cells and eosinophils, and this activity was inhibited by the anti-GM-CSF antibody. In addition, the presence of several cytokines in the supernatant of nasal epithelial cell cultures has been reported. These observations suggest the possibility that GM-CSF and cytokines play an important role in the allergic and inflammatory reactions of the nasal mucosa. In the present study epithelial cells of nasal mucosa were cultured under different conditions to find out the optimal conditions of production for GM-CSF and interleukin-6 (IL-6). When the concentration of fetal calf serum (FCS) in the culture medium was varied, the number of cultured epithelial cells and the concentration of GM-CSF and IL-6 in the supernatant showed an FCS concentration-dependent increase. When nasal mucosal epithelial cells were cultured in 15% FCS, production of both GM-CSF and IL-6 was increased with increasing duration of incubation. There was no significant difference in production of GM-CSF or IL-6 between the patients with allergic rhinitis and those with nasal polyps. These results suggest that neither allergic rhinitis and nor nasal polyposis are associated with the ability of epithelial cells to produce cytokines, but the interplay of various factors in the epithelial layer, as well as of diseases, affects their ability to produce cytokines. When the condition of epithelial cell propagation was rendered favorable or unfavorable by varying the concentration of FCS in the culture medium, using the same culture system, production of GM-CSF and IL-6 was increased in a dose-dependent manner (%) favoring epithelial cell growth. These observations indicate that epithelial cells produce GM-CSF and IL-6 only when conditions are favorable for their proliferation is required.