Reciprocal regulation of cultured human mast cell cytokine production by IL-4 and IFN-gamma

Background: T(H)1 and T(H)2 cytokines are thought to regulate allergic infl ammation. Objective: Two key regulatory cytokines, IL-4 and IFN-gamma, were examined for their effects on cytokine production by cultured human mast c ells (CHMCs). Methods: CHMCs were obtained by culturing cord blood-derived CD34(+) cells in the presence of stem cell factor and IL-6 for 14 to 16 weeks. CHMCs were passively sensitized with human myeloma IgE and supplemented with or witho ut IL-4 or IFN-gamma. After the sensitization, CHMCs were stimulated with a nti-Fc epsilon RI alpha mAb. Concentrations of secreted cytokines were meas ured by using ELISA, and cytokine messenger RNA was analyzed by using quant itative competitive RT-PCR. Results: IL-4 profoundly enhanced Fc epsilon RI-mediated production of macr ophage inflammatory protein (MIP) 1 alpha, IL-8, and CM-CSF For example, th e enhancement by IL-4 (10 ng/mL) of the production of MIP-1 alpha IL-8, and GM-CSF was 25-, 7-, and 90-fold, respectively, after 6 hours. IL-4 also en hanced levels of Fc epsilon RI-induced cytokine messenger RNA but to a Less er degree. in contrast, IFN-gamma inhibited Fc epsilon RI-induced productio n of MIP-1 alpha l IL-8, and GM-CSF. For example, the inhibition by IFN-gam ma (10 ng/mL) of Fc epsilon RI-mediated production of MIP-1 alpha, IL-8, an d GM-CSF was 80%, 75%, and 95%, respectively. IFN-gamma also suppressed Fc epsilon RI-induced messenger RNA expression of these cytokines. Neither IL- 4 nor IFN-gamma affected the kinetics of cytokine production by CHMCs. Conclusion: These data suggest that IL-4 and IFN-gamma may influence allerg ic reactions by modulating human mast cell cytokine production.