IL-15 promotes cytokine production of human T helper cells

IL-15 is a newly identified cytokine that has T cell and B cell growth factor activity similar to that of IL-2. In this study, a novel biologic function of IL-15 to promote cytokine production by human Th cells has been elucidated. Dermatophagoides farinae 11 (a major allergen of house dust mite)-specific human T cell clones produced IL-5 in response to recombinant human IL-15 as well as to either anti-CD3 or IL-2 stimulation. IL-5 mRNA became detectable 3 h after IL-15 stimulation and reached a maximum at 9 h. Human IL-5 promoter/enhancer-luciferase gene construct transfected to T cell clones was clearly transcribed in response to IL-15, indicating that the approximately 500-bp human IL-5 promoter/enhancer segment 5' upstream of the coding region sufficiently responded to IL-15. IL-15-induced IL-5 synthesis was completely inhibited by the tyrosine kinase inhibitor, herbimycin A, suggesting the involvement of tyrosine kinases in the signal transduction leading to IL-5 synthesis as well as to proliferation of T cells induced by IL-15. Whereas IL-5 production by human peripheral T cells was abolished by the addition of anti-IL-2-neutralizing Abs into the culture, IL-15 restored the IL-5 synthesis despite effective IL-2 neutralization. IL-15 produced at the site of allergic inflammation may play a role in the recruitment and activation of eosinophils by inducing IL-5 (a Th2 cytokine) production by T cells.

A novel phosphodiesterase inhibitor, T-440: possible management of eosinophilic inflammation by down-regulation of interleukin-5 production

The effect of T-440, a selective type IV phosphodiesterase (PDE IV) inhibitor on interleukin (IL)-5 production by peripheral blood mononuclear cells (PBMCs) of atopic asthmatic subjects was investigated. PBMCs produced IL 5 following challenge with specific allergen in vitro. T-440 suppressed allergen-induced IL-5 production significantly at a concentration of 1 microgram/ml. T-440 inhibited cyclic AMP-phosphodiesterase (PDE) activity in a concentration dependent manner and raised the intracellular cyclic AMP level of PBMCs significantly. Dibutyryl cyclic AMP suppressed IL-5 production by PBMCs in a similar way to T-440, suggesting that the increase of intracellular cyclic AMP caused by T-440 reduces IL-5 production. T-440 may be an effective agent to treat atopic diseases associated with eosinophilic inflammation, e.g. asthma and atopic dermatitis.

Age-related differential mRNA expression of T cell cytokines in NZB/NZW F1 mice

The mRNA expression of interleukin (IL)-2, IL-2 receptor-alpha-chain (IL-2R alpha), IL-4 and interferon-gamma (IFN-gamma) in spleen cells from NZB/NZW F1) mice following the stimulation with concanavalin A (Con A) was examined by Northern blot analysis. Kinetic patterns of the mRNA expression after the stimulation were not different between 2-month-old and 6 to 8-month-old B/W F1 mice. However, relative mRNA expression of IL-2 to a cytoskeletal protein, alpha-Tubulin was lower in 6 to 8-month-old B/W F1 mice than in 2-month-old mice. Similar but not significant tendency was observed in IL-2R mRNA expression. In contrast, Relative IL-4 mRNA expression in 6 to 8-month-old B/W F1 mice was significantly higher than that in 2-month-old animals. On the other hand, no apparent change was observed in IFN-gamma mRNA expression. Flow cytometric analysis indicated that there was no apparent difference in proportion of L3T4 positive T cells in spleen cells from 2 and 6 to 8-month-old B/W F1 mice. These results suggest that mRNA expression of IL-2 and IL-4 differentially changes with aging in autoimmune B/W F1 mice.

Enhanced production and gene expression of interleukin-5 in patients with bronchial asthma: possible management of atopic diseases by down-regulation of interleukin-5 gene transcription

Interleukin (IL)-5 was produced in vitro by peripheral blood mononuclear cells (PBMCs) of mite-sensitive atopic patients upon challenge with specific allergen, while PBMCs of healthy controls produced essentially no IL-5. Stimuli delivered by the combination of phorbol ester (PMA) and CA2+ ionophore (ionomycin) induced marked IL-5 production by PBMCs obtained from atopic as well as nonatopic asthmatics. CD2- or CD4-bearing-cell depletion almost completely removed IL-5 production and gene transcription while CD8 depletion did not. These findings indicated that CD4+ T cells are the principal source of IL-5 in asthmatic PBMCs. The capacity of PBMCs of atopic asthmatics, nonatopic asthmatics and healthy controls to produce IL-2, IL-3, IL-4, interferon-gamma and granulocyte/macrophage-colony-stimulating factor was comparable among the three groups. FK506 suppressed IL-5 production and gene expression in vitro in a dose-dependent manner.

[A case of sarcoidosis with right pneumothorax and multiple cavities in both lung fields]

A 26-year-old man was admitted to our hospital for evaluation of cavitary lesions on his chest X-ray film. Chest CT and conventional tomograms showed multiple cavities in both lung fields, as well as hilar and mediastinal lymphadenopathy. He had uveitis and the laboratory data showed a high level of angiotensin converting enzyme in the serum. Histological findings of the specimen obtained by transbronchial lung biopsy showed non-caseating epithelioid cell granuloma, consistent with sarcoidosis. Corticosteroid therapy (prednisolone 40 mg/day) resulted in reduction of the cavitary lesions and the lymphadenopathy. Negative bacteriological studies and the clinical course strongly suggested primary cavitation, a relatively rare form of pulmonary parenchymal involvement in sarcoidosis.

Oral immunotherapy may induce T cell anergy

Recently, the induction of T cell anergy has been considered as a sophisticated form of immunotherapy. However, the multiplicity of T cell allergen epitopes discourages the practical use of this method. Since orally administered antigen proteins are digested to peptides and absorbed into the circulation, oral administration of antigen might be an apparently primitive but practically very useful therapeutic approach. Freeze-dried body extract of Dermatophagoides farinae mite in tight capsules was orally administered at 0.5-3 mg/day to 17 adult male mite-sensitive asthmatic patients for 12 weeks. Marked and moderate improvement of clinical symptoms judged by symptom scores and peak expiratory flow was observed in 47% (8/17) of the patients. Bronchial provocation tests carried out before and after oral immunotherapy showed a statistically significant improvement especially in the late asthmatic response. The peripheral blood eosinophil count decreased significantly after oral immunotherapy. Interleukin-5 spontaneously produced by patient peripheral mononuclear cells decreased significantly (p < 0.05) after the oral immunotherapy. These results suggest that T cell anergy might be achieved by oral immunotherapy.

Allergen-specific human T cell clones produce interleukin-5 upon stimulation with the Th1 cytokine interleukin-2

CD4+ T cell clones specific for Der fII (a major allergen of the house dust mite) were established from peripheral blood mononuclear cells of atopic patients. All of the T cell clones were classified as having the Th0 phenotype, since they produced both interleukin (IL)-2 and IL-4 upon stimulation. Some of the clones produced IL-5 upon antigenic stimulation. Human recombinant IL-2 induced these T cell clones to express IL-5 mRNA and produce IL-5 protein in a dose-dependent manner. IL-2 did not induce IL-4 production, indicating a discrete signal requirement for IL-4 versus IL-5 production by T cells. Moreover, IL-5 production induced by immobilized anti-CD3 monoclonal antibody was completely suppressed by the addition of anti-IL-2 monoclonal antibody, suggesting that IL-5 production, designated as a Th2-type immune response, is dependent on IL-2, a Thl cytokine. IL-2 produced at the site of allergic inflammation may contribute to IL-5 production by T cells in vivo.

IL-5 production by CD4+ T cells of asthmatic patients is suppressed by glucocorticoids and the immunosuppressants FK506 and cyclosporin A

IL-5 was produced in vitro by peripheral blood mononuclear cells (PBMC) of mite-sensitive atopic patients upon challenge with specific allergen, while PBMC of healthy controls produced essentially no IL-5. Stimuli delivered by the combination of phorbol ester and Ca2+ ionophore induced marked IL-5 production by PBMC obtained from atopic and non-atopic asthmatics, suggesting that both protein kinase C and Ca2+ influx are required for IL-5 production. CD2- or CD4-bearing cell depletion almost completely removed IL-5-producing cells while CD8-bearing cell depletion rather enriched them. These findings indicate that CD4+ T cells are the principal source of IL-5 in PBMC. The capacity of PBMC of atopic asthmatics, non-atopic asthmatics and healthy controls to produce IL-2, IL-4, IL-5 and IFN-gamma was compared, to find that cytokine-producing capacities other than that of IL-5 (IL-2, IL-4 and IFN-gamma) were not significantly different among the three groups. Dexamethasone, FK506 and cyclosporin A suppressed IL-5 production in vitro in a dose-dependent manner. Clear dose-dependent suppression of IL-5 gene expression by FK506 was also observed. Treatment of asthmatic patients with inhaled glucocorticoid (beclomethasone dipropionate) ameliorated clinical symptoms, improved lung function and markedly suppressed IL-5 production by PBMC, suggesting the essential role of IL-5 in the pathogenesis of bronchial asthma and the clinical importance of its regulation.

Effect of fibronectin on the production of leukotriene C4 by eosinophils

The effect of fibronectin on leukotriene C4 (LTC4) production by eosinophils was examined. Eosinophils obtained from patients with bronchial asthma were cultured for 3 h with or without fibronectin and culture supernatants were assayed for LTC4 by specific enzyme immunoassay. LTC4 was produced in a time- and dose-dependent manner in the presence of fibronectin, and maximum production of LTC4 was observed 3 h after addition of 100 micrograms/ml of fibronectin. These results suggest that eosinophils may be activated by interaction with extracellular matrix proteins, including fibronectin, and play a role in the pathogenesis of bronchial asthma.

Effectiveness of disodium cromoglycate in food-dependent, exercise-induced anaphylaxis: a case report

An 18-year-old girl experienced anaphylactic reactions three times and frequent urticaria with exercise after meals that included wheat. Allergy evaluation showed a strong prick test reaction to wheat, and RAST score was 2 for wheat. Exercise provoked a decrease of FEV1 of 7.4% and increase of plasma histamine with no symptoms. Exercise after eating wheat provoked an FEV1 decrease of more than 18.7%, further increase of plasma histamine, urticaria and mild dyspnea. Oral administration of disodium cromoglycate before ingestion of bread and exercise challenge caused a maximal FEV1 increase of 6%, no increase of the plasma histamine, and no symptoms.

Accumulation of multiple T cell clonotypes in lungs of healthy individuals and patients with pulmonary sarcoidosis

T cell accumulation and activation in lung may play a major role in the pathogenesis of immunologic lung diseases such as sarcoidosis. Using the combination of RT-PCR and subsequent single-strand conformation polymorphism analysis, we examined T cell clonality in lung and peripheral blood of healthy individuals (n = 5) and patients with active pulmonary sarcoidosis (n = 7). RNA was extracted from PBLs and bronchoalveolar lavage fluid cells, and converted to cDNA. PCR was performed using a set of V beta-C beta primers (V beta 1-20). Products were denatured and electrophoresed in nondenaturing 5% polyacrylamide gel. The existence of a distinct T cell clonotype was detected as a band on a smear. In both groups T cells in PBLs showed a number of clones that expanded. A significantly greater number of clones was detected in BAL compared with PBL in both groups (normal: 25.3 +/- 7.2 in PBL vs 62.8 +/- 5.2 in lung; sarcoid: 25.0 +/- 6.2 in PBL vs 90.0 +/- 6.6 in lung, mean value +/- SEM). In sarcoid lung greater numbers of clones were detected than in lungs of healthy controls (p < 0.012). These clonal expansions were observed over all the 20 V beta families examined, and were not restricted to certain V beta families. These results suggest that there are clonal expansions even in normal lung, and that in sarcoidosis, apparently, additional T cell clones using multiple V beta segments might be activated and accumulated at the site of the disease.

Accumulation of multiple T cell clonotypes in lungs of healthy individuals and patients with pulmonary sarcoidosis

T cell accumulation and activation in lung may play a major role in the pathogenesis of immunologic lung diseases such as sarcoidosis. Using the combination of RT-PCR and subsequent single-strand conformation polymorphism analysis, we examined T cell clonality in lung and peripheral blood of healthy individuals (n = 5) and patients with active pulmonary sarcoidosis (n = 7). RNA was extracted from PBLs and bronchoalveolar lavage fluid cells, and converted to cDNA. PCR was performed using a set of V beta-C beta primers (V beta 1-20). Products were denatured and electrophoresed in nondenaturing 5% polyacrylamide gel. The existence of a distinct T cell clonotype was detected as a band on a smear. In both groups T cells in PBLs showed a number of clones that expanded. A significantly greater number of clones was detected in BAL compared with PBL in both groups (normal: 25.3 +/- 7.2 in PBL vs 62.8 +/- 5.2 in lung; sarcoid: 25.0 +/- 6.2 in PBL vs 90.0 +/- 6.6 in lung, mean value +/- SEM). In sarcoid lung greater numbers of clones were detected than in lungs of healthy controls (p &lt; 0.012). These clonal expansions were observed over all the 20 V beta families examined, and were not restricted to certain V beta families. These results suggest that there are clonal expansions even in normal lung, and that in sarcoidosis, apparently, additional T cell clones using multiple V beta segments might be activated and accumulated at the site of the disease.

Regulation of interleukin-5 production by peripheral blood mononuclear cells from atopic patients with FK506, cyclosporin A and glucocorticoid

Upon stimulation with phorbol ester and ionomycin, peripheral blood mononuclear cells (PBMC) of atopic patients with moderate eosinophilia produced significantly higher amounts of IL-5 compared to that of normal subjects. This finding renders further support to the notion that T cell-eosinophilic inflammation plays a central role in allergic disorders. IL-5 induction in vitro was completely inhibited by immunosuppressant FK506, cyclosporin A and dexamethasone. FK506 applied in vivo effectively suppressed clinical symptoms of atopic dermatitis and IL-5 production of PBMC. FK506 and cyclosporin A may become a better therapeutic modality against allergic diseases.

[The potential role and mechanism of leukotriene and platelet-activating factor in allergic disease]

Eosinophilic accumulation in the airway is a prominent feature in patients with bronchial asthma (chronic desquamative eosinophilic bronchitis). Recently, arachidonic acid metabolite such as leukotriene, 15-HETE and PAF are proved to play an essential role as chemical mediators in the pathogenesis of bronchial asthma. A close relation is found between eosinophils activation and those mediators. The bronchoconstrictive leukotriene (LT C4, D4, E4) are generated mainly from eosinophils and mast cells, while the chemoattractive LTB4 is produced from neutrophils. Platelet activating factor (PAF) is postulated as a causative mediator of the eosinophilic airway inflammation and bronchial hyperresponsiveness because PAF attracts and activates preferentially eosinophils. Evidence that eosinophils have ability to produce PAF like other inflammatory cells suggests an autocrine mechanisms of the eosinophil activation by PAF.

[A case of asymptomatic endobronchial lipoma followed for 4 years]

Bronchoscopy was performed on a 68-year-old male patient with pulmonary tuberculosis, and revealed a yellow smooth polypoid tumor in the lumen of the left upper division bronchus. The histopathological diagnosis of the biopsy specimen was endobronchial lipoma. Since the patient did not have any symptoms due to the lipoma, we performed treatment for tuberculosis and continued careful observation of the tumor. During the subsequent 4 years, the patient developed no complications such as obstructive pneumonia, and the size of the tumor under bronchoscopic observation did not change. Endobronchial lipoma is a very rare benign tumor. Almost all reported cases have undergone operation or endoscopic surgery. This case is the first that was followed over 4 years without surgical procedure. The findings of follow-up bronchoscopic examination suggest that the growth rate of endobronchial lipoma is very slow. Furthermore, we reviewed 36 cases of endobronchial lipoma in the Japanese literature, including our case. Smoking seems to have a strong relation to the occurrence of the tumor. It is noteworthy that 6 cases had separate malignancies, but the direct relationship between endobronchial lipoma and such malignancies is unclear.

Hypersensitivity pneumonitis in athymic nude mice. Additional evidence of T cell dependency

We previously demonstrated that C57 Black/6 mice develop lung lesions similar to human hypersensitivity pneumonitis (HP) by repeated transnasal administration of Thermoactinomyces vulgaris (Tv) antigen. To elucidate the role of T cells in the development of this disease, Tv antigen (90 micrograms/day) was transnasally administered to athymic nude C57 Black/nu/nu (nu) mice and their littermates (+/nu) three times a week for 3 wk. The nude mice developed minimal lung lesions, whereas their thymus-intact littermates (+/nu) showed changes equivalent to those in C57 Black/6. Changes in local inflammatory cell responses were evaluated by bronchoalveolar lavage, and increases in the numbers of lymphocytes and macrophages were significantly less severe in the nude mice than in the +/nu mice. Interestingly, the increase in polymorphonuclear leukocytes 6 h after the last antigen inoculation was equivalently seen in both groups. When spleen-derived T cells (more than 95% Thy-1.2+) from the sensitized +/nu mice were adoptively transferred to nude mice, the HP-like lesions in the recipients were found after Tv antigen challenge. These results suggest that Thy-1.2+ T cell-mediated immunity was necessary for the development of HP in this murine model.

Is a trypsin-like protease of mites a Der f III allergen?

A trypsin-like protease was purified from mite (Dermatophagoides farinae) fecal extract. In SDS-PAGE, the mite trypsin-like protease showed a single band at 34 kD. The purified trypsin-like protease possessed potent allergenic activity. Both the twenty N-terminal amino acid sequence and the amino acid composition of the purified protease were very similar to those of Der f III. These data strongly suggest that the trypsin-like protease in the mite is a Der f III allergen.

Cloning and expression of cDNA coding for the major house dust mite allergen Der f II in Escherichia coli

A cDNA library corresponding to mite protein was screened using anti-Der f II, a major allergen from the house dust mite Dermatophagoides farinae, antibody. Three possible clones were obtained that contained cDNA fragments coding for Der f II, and the nucleotide sequences of the fragments were determined. There were minor differences observed affecting the deduced amino acid sequence among the three cDNA fragments. The amino acid sequence of the purified native Der f II protein could be analyzed to 45 residues from the N-terminus. As a result of comparison, all the three cDNA fragments code for a mature protein with a derived molecular weight of about 14,000. The amino acid sequence was not homologous to any known protein sequences and it contained six cysteine residues and no N-glycosylation sites.

[Histamine release test of patients allergic to the house dust mite, Dermatophagoides farinae--analysis according to various clinical backgrounds]

Since the histamine release test is more complicated than some of the other tests, there are smaller number of clinical studies employing this method. In this study, we selected 25 males and 20 females, allergic to the house dust mite, to undergo the histamine release test challenged by 7 serial concentrations of the mite allergen diluted from 10 times to 10 million times the original allergen at a concentration of 0.01%. Histamine release was expressed as a percentage of the total histamine concentration contained in the cells. Allergen induced dose response curve of histamine release was drawn for each patient, and in order to characterize each curve, 5 different indices were selected and were averaged according to the clinical backgrounds of the patients. Significant increases in histamine release were observed in males under 25 and females above 26 years of age. Histamine release rate in patients with RAST score of above 3+ was significantly more enhanced than in those with RAST score of below 2+, though this result was significant only for those under 25 years of age. Blood samples taken in June-August, and September-November, showed significant increases in the histamine release, though the indices for enhancement differed in both seasons. When analyzed according to the numbers of years the patient was desensitized, the results showed, contrary to our expectations, a more increased release in the desensitized group than in the non-desensitized group.

T-cell-dependent accumulation of eosinophils in the lung and its inhibition by monoclonal anti-interleukin-5

The transnasal administration of an extract of the parasite Ascaris suum to C57BL/6 mice for 3 weeks produced marked eosinophilia in the bronchoalveolar lavage (BAL) fluid. The oral administration of ciclosporin significantly suppressed the pulmonary eosinophilia. Athymic C57BL/6-nu/nu mice failed to develop pulmonary eosinophilia. These data indicate that the pulmonary eosinophilia caused by this parasite extract is T-cell-dependent. Genetically mast-cell-deficient (WB x C57BL/6) F1-W/Wv (W/Wv) mice developed marked eosinophilia in the BAL, which shows that mast cells are not necessary in the formation of lung eosinophilia in this model. Monoclonal antimurine interleukin-5 injected intraperitoneally clearly inhibited the infiltration of eosinophils in the lung, suggesting that T-cell-derived interleukin-5 is essential.

Food-dependent, exercise-induced anaphylaxis: a study on 11 Japanese cases

Eleven patients with food-dependent, exercise-induced anaphylaxis were studied. Seven patients experienced anaphylactic symptoms only after eating certain foods, such as shellfish, wheat, and grape before exercise. In the remaining four patients, no specific food could be identified, but the act of eating itself predisposed to anaphylaxis. Their anaphylactic symptoms were all clearly distinguished from cholinergic urticaria by history. Patients who developed anaphylactic symptoms before 20 years of age (N = 7) were atopic themselves or had atopic first-degree relatives. Six patients had increased serum IgE levels, and IgE antibodies against the causative food allergens were detected by the skin prick test or RAST in four cases. In contrast, patients who developed the symptoms after 30 years of age (N = 4) appeared to have a less atopic background, and IgE levels were within normal range except in one case. Three of four patients in the latter group developed symptoms after ingesting food made of wheat followed by exercise. All patients were sensitive to wheat as determined by the skin prick test. In six of 11 patients, a considerable rise in plasma histamine concentration was observed after exercise challenge with treadmill alone, and food intake followed by exercise induced a further increase in one patient.

Synthesis of biologically active recombinant Der f II

A cDNA library corresponding to mite protein was screened employing anti-Der f II antibody. Two possible clones containing plasmids pFL1 and pFL11 were obtained. The two plasmids had insertions of about 500 basepairs. The DNA sequences of the two insertions were determined, from which the amino acid sequences were deduced. The amino acid sequence of the purified native Der f II protein could be determined to 45 residues from the N terminus. As a result of comparison, we concluded that the cDNAs prepared from live Dermatophagoides farinae mite corresponded to the mite allergen Der f II. The recombinant Der f II was biologically active.

Inhibition of allergen-induced bronchoconstriction in sensitized guinea pigs by orally administered allergen

Crude mite extract (CME) was orally administered to guinea pigs sensitized to CME. It was shown that such treatment reduces the bronchoconstrictive response upon allergen provocation. Isolated tracheae taken from guinea pigs orally administered CME allergen showed less contraction in response to CME as compared to those obtained from sensitized but not orally treated animals. The oral administration of allergens seemed to attenuate the bronchial hyperresponsiveness of sensitized animals to a non-specific chemical stimulus (histamine). IgE antibodies titrated by 8 days passive cutaneous anaphylaxis, and IgG1 and IgG2 antibodies measured by ELISA were comparable in the sera obtained from animals before and after CME treatment.