CROSS-LINKING OF THE HIGH-AFFINITY IGE RECEPTOR INDUCES THE EXPRESSION OF CYCLOOXYGENASE-2 AND ATTENDANT PROSTAGLANDIN GENERATION REQUIRINGINTERLEUKIN-10 AND INTERLEUKIN-1-BETA IN MOUSE CULTURED MAST-CELLS

When mouse bone marrow-derived mast cells (BMMC) developed in interleu kin (IL)-3 were activated with IgE and antigen (IgE/antigen) in the pr esence of both IL-10 and IL-1 beta, two sequential phases of prostagla ndin (PG)D-2 generation were elicited, in which the first phase occurr ed by 1 h and the second phase from 2 to 10 h. The delayed phase of PG D(2) generation was accompanied by a marked induction of cyclo-oxygena se (COX)-2 mRNA, which reached a peak at 1-2 h, followed by that of it s protein from 2-10 h, with a peak at 5 h. The immediate phase of PGD( 2) generation was completely abrogated by the irreversible inhibition of pre-exisiting COX-1 by aspirin pretreatment, whereas the delayed ph ase of PGD(2) generation was almost undetectable in the presence of th e COX-2 inhibitor NS-398. A detailed analysis of the individual effect s of IgE/antigen, IL-10 and IL-1 beta on COX-2 expression revealed tha t IgE/antigen and IL-10 each initiated and stabilized COX-2 mRNA expre ssion, leading to an increase in the expression of its protein. Conver sely, IL-1 beta stabilized the COX-2 protein without affecting its mRN A level. The induction of COX-2 by IgE/antigen with IL-10 and IL-1 bet a preceded the induction of transcripts for endogenous cytokines such as IL-6, IL-1 beta and IL-10. The inhibition of PGD(2) generation by i ndomethacin did not affect the induction of COX-2 or these cytokines. Thus the two major delayed-phase responses of BMMC after IgE-dependent activation, namely COX-2-dependent PGD(2) generation and cytokine pro duction, are regulated independently.