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Interleukin (IL)-9 has recently been shown to play an important role in allergic disease because its expression is strongly associated with the degree of airway responsiveness and the asthmatic-like phenotype. IL-9 is a pleiotropic cytokine that is active on many cell types involved in the allergic immune response. Mucus hypersecretion is a clinical feature of chronic airway diseases; however, the mechanisms underlying the induction of mucin are poorly understood. In this report, we show that IL-9 regulates the expression of a subset of mucin genes in lung cells both in vivo and in vitro. In vivo, the constitutive expression of IL-9 in transgenic mice results in elevated MUC2 and MUC5AC gene expression in airway epithelial cells and periodic acid-Schiff-positive staining (reflecting mucous glycogenates). Similar results were observed in C57BL/6J mice after IL-9 intratracheal instillation. In contrast, instillation of the T helper 1-associated cytokine interferon gamma failed to induce mucin production. In vitro, our studies showed that IL-9 also induces expression of MUC2 and MUC5AC in human primary lung cultures and in the human muccoepidermoid NCI-H292 cell line, indicating a direct effect of IL-9 on inducing mucin expression in these cells. Altogether, these results suggest that upregulation of mucin by IL-9 might contribute to the pathogenesis of human inflammatory airway disorders, such as asthma. These data extend the role of the biologic processes that IL-9 has on regulating the many clinical features of asthma and further supports the IL-9 pathway as a key mediator of the asthmatic response.

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ABSTRACT. Hypothesis. Activated CD8 as well as CD4 T cells contribute to the production of asthma-relevant cytokines in both atopic and nonatopic childhood asthma.Objectives. To measure the percentages of peripheral blood CD4 and CD8 T cells expressing naïve/memory (CD45RA/CD45RO) and activation (HLA-DR, CD25) markers, as well as mRNA-encoding interleukin-4 (IL-4) and interleukin-5 (IL-5) in atopic and nonatopic childhood asthmatics and in nonasthmatic controls matched for age and atopic status; and to study the effects of inhaled glucocorticoid therapy of the asthmatics on these measurements.Methods. Peripheral blood mononuclear cells were isolated from 17 atopic and 8 nonatopic stable (not acutely ill) asthmatics aged 7 to 16 years with moderateto-severe disease and from 15 nonasthmatic controls matched for age and atopic status. Activation markers on CD4 and CD8 T cells were measured by flow cytometry, and expression of cytokine mRNA by in situ hybridization with CD4 and CD8 T cells were isolated using magnetic beads. Measurements were repeated in 18 of the asthmatics 4 to 6 months after initiation or escalation of inhaled glucocorticoid therapy for inadequately controlled asthma.Results. The percentages of CD4 T cells expressing CD45RO but not CD45RA were elevated in both asthma groups as compared with the relevant controls and were reduced in association with de novo or augmented inhaled glucocorticoid therapy. The percentages of CD8 T cells expressing both markers were not elevated in asthmatics as compared with controls. The percentages of both CD4 and CD8 T lymphocytes expressing HLA-DR and CD25 were elevated in the asthmatics as compared with controls, and significantly reduced in association with de novo or augmented inhaled glucocorticoid therapy. ABBREVIATIONS. IL-5, interleukin 5; IL-4, interleukin 4; IgE, immunoglobulin E; FEV1, forced expiratory volume in 1 second; PEF, peak expiratory flow; FITC, fluoroscein isothiocyanate; PE, phycoerythrin; PBS, phosphate-buffered saline; NK, natural killer.

Sixteen structural analogs of leukotrienes C and D were tested for their contractile activities on guinea pig pulmonary parenchymal strip and ileum. The analogs differed from the native structures in the position of either the thioether-linked peptide side chain or the hydroxyl group (or both) or in the number and positions of ethylenic bonds. Analogs in which the thioetherlinked peptide chain was attached other than at the C-6 position had substantial reductions in activity on both smooth muscle preparations, whereas analogs in which the various ethylenic bonds were saturated retained substantial contractile activity in both assays. These observations demonstrate that, although a hydrophobic region ofthe eicosinoid is necessary for contractile activity, the length of this segment is more critical than its precise stereochemistry. Analogs of leukotrienes based on the possibility of parallel biosynthetic routes deriving from 8-, 11-, and 15-hydroperoxyeicosatetraenoic acid as precursors were found to effect a comparatively weak contractile response so that their role as biological agents in this respect seems unlikely.The recent demonstration that the biological activity of slowreacting substance of anaphylaxis represents the combined effects of5(S)-hydroxy-6(R)-S-glutathionyl-7,9-trans, 11, 14-cis-eicosatetraenoic acid, leukotriene C (LTC) (1-3), and its 6-sulfidocysteinylglycine (4, 5) and 6-sulfido-cysteine analogs (LTD and LTE, respectively) (6) has been associated with an appreciation of their potency in several biological assay systems. For example, the respective activities of LTC and LTD are 500 and 10,000 times greater on a molar basis than is histamine in effecting a contractile response of the guinea pig pulmonary parenchymal strip and 7Q-250 times greater in effect on guinea pig ileum. The molecular structures of these leukotrienes incorporate a polar region from the eicosinoid carboxyl through the C-6 peptide, with the remainder ofthe molecule being nonpolar. We have previously shown a modest decrement in the contractile effects of these compounds on guinea pig ileum and pulmonary parenchymal strip by alteration of the 11,12 ethylenic bond from the cis to the trans conformation, with a greater loss in activity as the C-6 peptide changes from glutathione to cysteine in LTC, LTD, and LTE, respectively (6). We now report the comparative contractile activities of three types of analogs of LTC and LTD.In the first series, certain of the double bonds of the leukotriene structure were replaced by single bonds, so that the effect of geometrical changes in the hydrophobic C-7 to C-20 region of the leukotrienes could be assessed. The second series of analogs is comprised ofstructures (1, 2, and 3) (Fig. 1), which could result from a leukotriene-like biosynthetic mechanism (7) proceeding not from 5-hydroperoxyeicosatetraenoic acid (5-HPETE), the precursor ofleukotrienes, but from 11-HPETE, 15-HPETE, and 8-HPETE instead. Study of the second series not only allows testing of the possible products of natu...

Twenty-three structural analogs of the leukotriene components of slow reacting substance of anaphylaxis (SRS-A), in which the polar regions of the leukotriene were systematically modified, were tested for their contractile activities on guinea pig pulmonary parenchymal strips and guinea pig ileum. The structural modifications allowed evaluation of the separate contributions of the four polar units in the C-1 to C-6 region ofthe SRS-A leukotrienes to smooth muscle spasmogenic activity. The free NH2-terminal amino group of the S-linked peptide was necessary for full activity, and its deletion or substitution reduced activity by more than one but less than two orders of magnitude. A similar level of importance was apparent for the free glycine carboxyl group. In contrast, a free eicosanoid carboxyl at C-1 is not required for full activity on the airway and for substantial activity on the ileum. A role for the C-5 hydroxyl is indicated by the inactivity of the one available 5-desoxy analog. Nucleophilic, divalent sulfur is not critical to leukotriene D (LTD) activity, in that one sulfoxide had substantial function. The conformational relationship between the eicosanoid and peptide moieties of LTD is of considerable importance in that epimers at the C-5 or C-6 position were less active than LTD by more than two orders of magnitude. Several lines of evidence suggest that the relative geometrical arrangement of the C20 chain and the peptide unit is important to activity, consistent with the existence of a true receptor for LTD.