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Biomedical subjects

H F Kauffman

Publications and source records attributed to H F Kauffman.

At least 37 records · Page 2Linked to original sources
PubMed2001

Resistance of activated human Th2 cells to NO-induced apoptosis is mediated by gamma-glutamyltranspeptidase.

Activation-induced death of inflammatory cells (AICD) has an important function in immune maintenance. Type 1 Th cells are known to be more susceptible to AICD than Th2 cells. In the current study we examined whether NO-induced apoptosis also preferentially eliminates Th1 cells over Th2 cells. Naive human Th lymphocytes (CD4(+)CD45RO(-)) were activated in vitro for 1 week in the presence of IL-12 plus anti-IL-4 or IL-4 plus anti-IL-12 to generate Th1- and Th2-polarized cultures respectively. Cultures were exposed to the NO donors Spermine-nonoate (Sper) and DPTA-nonoate to study NO-induced apoptosis. We found that NO preferentially induced apoptosis in Th1-polarized cells as demonstrated by Annexin staining in the presence of 10 microM Sper (70 +/- 16 versus 23 +/- 4.4% in Th2 cells P: < 0.01) and by DioC6 staining (38 +/- 10 versus 11 +/- 5% in Th2 cells, P: < 0.01). The mechanism of NO-induced apoptosis in Th1/Th2-polarized cells was distinct from AICD and Fas-induced apoptosis. Differential sensitivity between Th1- and Th2-polarized cultures originated at the level of intracellular glutathione (GSH) metabolism. GSH levels were higher in Th2 cells (1.6 +/- 0.2-fold Th1, P: < 0.01). High intracellular GSH in Th2-polarized cells did not account for reduced susceptibility to NO per se, since the inhibition of gamma-glutamyltrans-peptidase (gamma-GT), which is involved in GSH import, sensitized Th2 cells to NO-induced apoptosis without GSH depletion. Therefore, higher activity of gamma-GT in Th2 cells (2.1 +/- 0.4-fold Th1, P: < 0.001) specifically protects Th2 cells against NO-induced apoptosis. Preferential NO-induced elimination of human Th1 cells at sites of inflammation may thus select Th2 cells and contribute to immune deviation.

Apoptosis↗
PubMed2001

PC(20) adenosine 5'-monophosphate is more closely associated with airway inflammation in asthma than PC(20) methacholine.

Inhalation of a direct stimulus such as histamine or methacholine is generally used to measure bronchial hyperresponsiveness (BHR). Provocation with adenosine 5'-monophosphate (AMP), an indirect airway challenge, has been suggested to be a better marker of airway inflammation than direct challenges. However, so far little information on this subject is available. The aim of our study was to assess whether the concentration of AMP causing the FEV(1) to drop by 20% (PC(20)) is more closely associated with inflammatory parameters in asthma than PC(20) methacholine. In 120 patients with atopic asthma (median FEV(1) 81% predicted [pred], median age 27 yr), PC(20) methacholine and PC(20) AMP as well as sputum induction, blood sampling, and measurement of nitric oxide in exhaled air were performed. PC(20) methacholine was predominantly predicted by FEV(1) %pred (explained variance [ev] = 18%) with the percentage of peripheral blood monocytes being a weak additional independent predictor (total ev = 23%). By contrast, PC(20) AMP was predominantly predicted by the percentage of eosinophils in sputum (ev = 25%), while FEV(1) %pred was only an additional independent predictor (total ev = 36%). PC(20) AMP reflects more closely the extent of airway inflammation due to asthma than PC(20) methacholine.

Adenosine Monophosphate↗
PubMed2000

Cyclosporine, FK506, mycophenolate mofetil, and prednisolone differentially modulate cytokine gene expression in human airway-derived epithelial cells.

BACKGROUND: The immunosuppressive effects of cyclosporine (CsA), tacrolimus (FK506), mycophenolate mofetil (MMF), and prednisolone in cells from the immunological compartment are well documented. In contrast, limited information is available with respect to the effects of these immunosuppressive drugs on airway-epithelial cells, although these cells may contribute to the development of obliterative bronchiolitis (OB) through the production of interleukin (IL)-6 and IL-8. METHODS: We studied the production of IL-6 and IL-8 proteins by airway-derived epithelial cell lines and primary epithelial cell cultures obtained from lung brushings. Transcriptional mechanisms were detected by transient transfections. RESULTS: We demonstrate that CsA dose dependently induces the production of the proinflammatory cytokines IL-6 and IL-8 in both cell lines and primary epithelial cells. FK506 and MMF were also able to upregulate IL-8, although the effect was less dramatic than observed for CsA. Low concentrations of prednisolone (0.01 and 0.001 microg/ml) enhanced IL-6 and IL-8 secretion, whereas concentrations > or =0.01 microg/ml significantly diminished IL-6 secretion. Furthermore, we showed that CsA and prednisolone mediate their effects at the transcriptional level. CONCLUSIONS: The data provide evidence that relevant concentrations of CsA and MMF in vivo may enhance the inflammatory processes in the lower airways of patients after lung transplantation.

Cells, Cultured↗
PubMed2000

Putative virulence factors of Aspergillus fumigatus.

Various putative virulence factors of Aspergillus fumigatus have been studied over the past decades. A. fumigatus gliotoxin is a potent inhibitor of the mucociliary system. Several fungal metabolites interfere with phagocytosis and opsonization including toxins, 'conidial inhibitory factor', 'A. fumigatus diffusible product' and 'complement inhibitory factor'. A. fumigatus can bind specifically to different host tissues components, whereas toxins give a general and significant immunosuppressive effect on host defences. Circumstantial evidence links the production of elastinolytic proteases with the ability to cause disease. However, none of the reports demonstrates conclusively a decisive role for any of the virulence factors described thus far. It is conceivable that proteolytic enzyme activities such as those expressed by AFAlp are one of a number of factors, each with a minor effect, that combine to facilitate disease progression.

Aspergillosis↗
PubMed2000

Airway inflammation and hyperresponsiveness to adenosine 5'-monophosphate in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is often accompanied by bronchial hyperresponsiveness (BHR). Measurement of BHR may give information about airway inflammation. OBJECTIVE: To investigate the role of airway inflammation in hyperresponsiveness to adenosine 5'-monophosphate (AMP) in COPD. METHODS: We investigated inflammatory indices in induced sputum, bronchoalveolar lavage (BAL) fluid and bronchial biopsies in subjects with COPD with and without hyperresponsiveness to AMP. Twelve nonatopic subjects with COPD with hyperresponsiveness to AMP (mean +/- SD, age 63 +/- 8 years, FEV1% predicted 56 +/- 13%), six without BHR (age 60 +/- 6 years, FEV1% predicted 65 +/- 11%) and 11 healthy nonatopic controls without BHR (age 58 +/- 8 years, FEV1% predicted 104 +/- 11%) participated in the study. RESULTS: Subjects with COPD with BHR had significantly higher numbers of mucosal CD8 + and higher percentages of sputum eosinophils than those without BHR (median, 550 cells/mm2; range, 30-1340 vs 280 cells/mm2; range, 110-450, P = 0.045; and median, 2.7%; range, 0.5-8.5 vs 0.6%; range, 0-0.8 %, P = 0.0036, respectively). No differences were observed in BAL fluid. CONCLUSION: We conclude that hyperresponsiveness to AMP in COPD is associated with airway inflammation that is characterized by increased numbers of mucosal CD8 + cells and percentages of sputum eosinophils. Hyperresponsiveness to AMP may be used as a marker of airway inflammation in COPD, but its significance in the clinical course remains to be determined.

Adenosine Monophosphate↗
PubMed2000

Protease-dependent activation of epithelial cells by fungal allergens leads to morphologic changes and cytokine production.

BACKGROUND: Proteases in extracts of Aspergillus fumigatus cause epithelial cell desquamation and release of proinflammatory cytokines. OBJECTIVE: We sought to assess protease activity in Alternaria alternata, Cladosporium herbarum, and Aspergillus fumigatus extracts and study the ability of these extracts to cause desquamation and release of proinflammatory cytokines from epithelial cells. METHODS: Protease activities of the fungal extracts were quantified. Changes with respect to cell morphology, cell desquamation, and cytokine production (IL-6 and IL-8) were measured in the absence and presence of the fungal extracts in an airway-derived epithelial cell line (A549) and primary epithelial nasal cells. RESULTS: Fungal proteases differentially induced morphologic changes, cell desquamation, and production of IL-6 and IL-8 in a dose- and time-dependent fashion. Alternaria alternata extracts induced cell shrinking and cell desquamation and strongly enhanced the production of IL-6 and IL-8 at higher concentrations. Aspergillus fumigatus extracts caused cell shrinking, cell desquamation, and production of IL-6 and IL-8, even at low concentrations. The Aspergillus fumigatus-derived extract grown on collagen medium induced a strong dose-dependent decline in cytokine production at higher concentrations. Cladosporium herbarum extracts did not induce morphologic changes or cell desquamation but enhanced IL-6 and IL-8 productions at higher concentrations. The dependence of these effects on intact protease activity was shown by their abrogation by protease inhibitors. CONCLUSION: Proteases present in fungal extracts interact with epithelial cells, leading to morphologic changes, cell desquamation, and induction of proinflammatory cytokines. It is proposed that these fungal proteases may activate epithelial cells through a protease-activated receptor type 2-driven mechanism.

Allergens↗
PubMed2000

Ongoing airway inflammation in patients with COPD who do not currently smoke.

BACKGROUND: Inflammatory changes in the airways in chronic obstructive pulmonary disease (COPD) are largely attributed to smoking, yet they may be present even if patients do not currently smoke. The differences in inflammatory cells and the factors contributing to these differences were examined in the airways of patients with COPD who do not currently smoke. METHODS: Eighteen non-atopic subjects with COPD (14 men) of mean (SD) age 62 (8) years and forced expiratory volume in one second (FEV(1)) 59 (13)% predicted and 11 non-atopic healthy subjects (eight men) of mean (SD) age 58 (8) years, FEV(1) 104 (11)% predicted were studied. Sputum induction and bronchoscopy with bronchoalveolar lavage (BAL) and biopsies were performed. RESULTS: Patients with COPD had more mucosal EG2+ cells (eosinophils) (median (range) 40 (0-190) versus 5 (0-40) cells/mm(2), p = 0.049) and CD68+ cells (1115 (330-2920) versus 590 (450-1580) cells/mm(2), p = 0.03), and a tendency towards more CD4+ but not CD8+ lymphocytes than healthy controls. Furthermore, patients with COPD had higher percentages of sputum neutrophils (77 (29-94) versus 36 (18-60)%, p = 0.001) and eosinophils (1.2 (0-8.5) versus 0.2 (0-3.1)%, p = 0.008), BAL fluid eosinophils (0.4 (0-1.7) versus 0.2 (0-0.5)%, p = 0.03), and higher concentrations of sputum eosinophilic cationic protein (ECP) (838 (115-23 760) versus 121 (35-218) ng/ml, p<0.001). Concentrations of ECP expressed per eosinophil were not higher. Patients with COPD with high mucosal EG2+ cell numbers also had high mucosal CD4+ cell numbers. Sputum eosinophilia was associated with a decrease in FEV(1)/VC and BAL fluid eosinophilia with a decrease in mucosal NP57+ cells (neutrophils). CONCLUSIONS: Subjects with COPD who do not currently smoke have increased numbers of inflammatory cells. Eosinophils are increased in number in the airways in COPD but do not seem to be activated. The increased eosinophil numbers are probably due to recruitment as a result of ongoing inflammation. Macrophages and lymphocytes may play a part in this inflammation.

Biopsy↗
PubMed2000

Effects of budesonide and formoterol on eosinophil activation induced by human lung fibroblasts.

Budesonide and formoterol are extensively used in current asthma therapy. Budesonide is known as potent antiinflammatory agent and formoterol also appears to have some antiinflammatory properties. We investigated inhibitory effects of these drugs on eosinophil activation in vitro as induced by fibroblast-conditioned medium (FCM). We measured the modulation of expression of clonal designator (CD)11b and L-selectin with flow cytometry after 4 h or 16 h of culture of eosinophils when budesonide or formoterol was applied either directly to the eosinophils while they were stimulated with FCM (direct method) or when each drug was applied to lung fibroblasts from which conditioned medium was then administered to eosinophils (indirect method). In the direct method, budesonide (10(-)(8) M) inhibited the modulation of CD11b (44 [25th to 75th percentiles: 26 to 66]% of control) and L-selectin (30 [-13 to 48]% of control) only after 16 h, and not after 4 h. Formoterol did not directly inhibit the modulation of eosinophil CD11b and L-selectin expression. In the indirect method, both budesonide and formoterol inhibited lung fibroblast activation, resulting in diminished eosinophil activation after 4 h. Budesonide or formoterol at 10(-)(8) M inhibited upregulation of CD11b to 26 [15 to 40]% and 38 [23 to 46]%, respectively, and inhibited L-selectin shedding to 14 [-3 to 50]% and 27 [2 to 62]%, respectively, of control values. These results show that budesonide inhibits eosinophil activation primarily through effects on lung fibroblasts, presumably by inhibiting production of granulocyte-macrophage colony-stimulating factor. After longer incubation periods, budesonide also directly inhibits eosinophil activation. In contrast, formoterol can inhibit eosinophil activation only via inhibitory effects on lung fibroblasts. We did not observe an additional effect of formoterol, beyond the effects induced by budesonide under any circumstance studied. Lung fibroblasts, in addition to eosinophils, may serve as important target cells for antiinflammatory treatment in asthma.

Adult↗
PubMed2000

Eosinophilic granulocytes and interleukin-6 level in bronchoalveolar lavage fluid are associated with the development of obliterative bronchiolitis after lung transplantation.

In a prospective cohort study, we assessed whether changes in total cell counts and differentiation and interleukin-6 (IL-6), IL-8, and monocyte chemoattractant protein-1 (MCP-1) concentrations in bronchoalveolar lavage fluid (BALF) are associated with a higher risk to develop obliterative bronchiolitis (OB). We investigated 60 lung transplant patients (follow-up of 2 to 8 yr) with either histologic evidence of OB within 1 yr after lung transplantation (n = 19) or no pathology, good outcome (GO) for at least 24 mo and well-preserved lung function, i.e., FEV > or = 80% of baseline (n = 41). Median time between lung transplantation and the first BAL was 42 d for the GO group and 41 d for the OB group (p > 0.05). In the bronchial fraction, median total cell counts (0.06 x 10(3)/ml versus 0.04 x 10(3)/ml), lymphocyte (9 x 10(3)/ml versus 2 x 10(3)/ml), and eosinophilic granulocyte counts (1 x 10(3)/ml versus 0) were significantly higher in the OB group than in the GO group (p < 0.05). In the alveolar fraction, this was the case for the median value of neutrophilic granulocyte counts (19 x 10(3)/ml versus 4 x 10(3)/ml), respectively. Median values of IL-6 and IL-8 concentrations in both bronchial (IL-6: 23 versus 6 pg/ml, IL-8: 744 versus 102 pg/ml) and alveolar fractions (IL-6: 13 versus 3 pg/ml, IL-8: 110 versus 30 pg/ml) of the BALF were significantly higher in the OB group than in the GO group. By means of logistic regression, we showed that higher total cell, neutrophilic granulocyte, and lymphocyte counts, the presence of eosinophilic granulocytes, and higher concentrations of IL-6 and IL-8 were significantly associated with an increased risk to develop OB. We conclude that monitoring cell counts, neutrophilic and eosinophilic granulocytes, IL-6, and IL-8 in BALF within 2 mo after lung transplantation in addition to the transbronchial lung biopsy (TBB) pathology will contribute to a better identification and management of the group of patients at risk for developing OB within a year.

Adult↗
PubMed2000

Budesonide and formoterol inhibit ICAM-1 and VCAM-1 expression of human lung fibroblasts.

The glucocorticoid budesonide and the long-acting beta2-adrenoceptor agonist formoterol are used in asthma therapy for their anti-inflammatory and bronchodilating effects, respectively. Since expression of adhesion molecules on resident cells in the lung plays an important role in asthmatic inflammatory responses, the effects of these drugs on the cytokine-induced intercellular adhesion molecule-1 (ICAM)-1 and vascular cell adhesion molecule-1 (VCAM)-1 expression of human lung fibroblasts were investigated. Budesonide and formoterol were added in the absence or presence of interleukin (IL)-1beta, tumour necrosis factor-alpha (TNF-alpha), interferon gamma (IFN-gamma) or IL-4 to human lung fibroblasts; ICAM-1 and VCAM-1 expression were measured after 8 h using a cell surface enzyme linked immunosorbent assay (ELISA). It was found that both budesonide and formoterol significantly inhibited (p<0.05) the increased expression of ICAM-1 and VCAM-1 after stimulation with IL-1beta (maximal inhibition (median (25-75% percentiles) 50 (48-52) and 61% (42-69), respectively, with budesonide and 55 (50-73) and 86% (64-94), respectively, with formoterol (10(-7) M)), TNF-alpha (maximal inhibition 49 (46-57) and 57% (44-68), respectively, with budesonide and 44 (40-75) and 62% (52-83) respectively, with formoterol), IFN-gamma (maximal inhibition 64% (41-67) with budesonide and 39% (29-49) with formoterol for ICAM-1) and IL-4 (maximal inhibition 82% (69-92) with budesonide and 43% (33-67) with formoterol for VCAM-1) in a dose-dependent manner. The results show that budesonide, as well as formoterol, in probably clinically relevant concentrations inhibits cytokine-induced adhesion molecule expression on human lung fibroblasts from a concentration of 10(-9) M. This inhibitory effect on resident cells may have implications for the infiltration of inflammatory cells into pulmonary tissue during therapy with these drugs in asthma.

Adrenergic beta-Agonists↗
PubMed1999

Clinical effects of air cleaners in homes of asthmatic children sensitized to pet allergens.

BACKGROUND: Exposure to cat and dog allergens is very common in the Western World and is a serious cause of asthma in sensitized subjects. OBJECTIVE: We sought to study the clinical effects of air cleaners in living rooms and bedrooms of asthmatic children sensitized to cat or dog allergens. METHODS: Twenty asthmatic children sensitized to pet allergens (cat/dog) and with an animal at home participated in a double-blind, placebo-controlled, cross-over study in which the effects of air cleaners placed in the living room and bedroom for 3 months were compared with the effects of sham air cleaners. Before and after each study period, lung function, airway hyperresponsiveness (adenosine monophosphate), and peak flow variation were recorded. Cat and dog allergen levels were assessed in the filters of the air cleaners. RESULTS: After a 3-month intervention with active air cleaners, airway hyperresponsiveness decreased significantly, showing a 1.2 doubling dose increase of PC(20 )adenosine (P =.003). Peak flow amplitude also decreased (P =. 045). Substantial amounts of airborne cat and dog allergen were captured by the air cleaners in living rooms and bedrooms as well. Allergen levels in floor dust were not changed. CONCLUSION: In young asthmatic patients sensitized and exposed to pets in the home, application of air cleaners in living rooms and bedrooms was accompanied by a significant improvement in airway hyperresponsiveness and a decrease in peak flow amplitude.

Administration, Inhalation↗
PubMed1999

Eosinophil derived neurotoxin (EDN) levels in commercial human urinary preparations of glycoprotein hormones.

Eosinophil derived neurotoxin (EDN) is a ubiquitous human ribonuclease, occurring not only in eosinophils, but also in many tissues and body fluids. It may be a contaminant of commercial human urinary preparations of chorionic gonadotropin (hCG) and other glycoprotein hormones. Here we describe the use of a fast commercial assay to quantify this contaminant and demonstrate that the content varies much between different commercial glycoprotein hormone preparations. As this ribonuclease may have a cytotoxic activity on certain cells, it is useful to be able to determine its quantity in a fast and reliable way in these preparations.

Antibodies, Monoclonal↗
PubMed1999

Interferon-gamma and interleukin-4 differentially regulate ICAM-1 and VCAM-1 expression on human lung fibroblasts.

The expression of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and more specifically vascular adhesion molecule-1 (VCAM-1) on lung fibroblasts may be important for migration of inflammatory cells through the submucosa to the airway lumen in the asthmatic inflammatory response. This study aimed to assess which cytokines are regulating ICAM-1 and VCAM-1 expression on human lung fibroblasts. For this purpose, confluent fibroblast cultures (derived from lung tissue from a nonasthmatic donor) were stimulated for 4 h with interleukin (IL)-1beta, tumour necrosis factor (TNF)alpha, interferon (IFN)gamma, IL-4, IL-5 or transforming growth factor (TGF)beta. IL-1beta (optimal concentration (OC) 1 U x mL(-1)) and TNFalpha (OC 100 U x mL(-1)) both increased ICAM-1 and VCAM-1 expression. IFNgamma (OC 2 U x mL(-1)) increased only ICAM-1 expression and IL-4 (OC 5 ng x mL(-1)) increased only VCAM-1 expression, whereas IL-5 (20 ng x mL(-1)) and TGFbeta (10 ng x mL(-1)) did not influence ICAM-1 or VCAM-1 expression. ICAM-1 expression reached a plateau at 8-12 h after cytokine stimulation and remained constant for at least 24 h. VCAM-1 showed a transient increased expression within 24 h after IL-1beta and TNFalpha stimulation. In contrast, VCAM-1 expression did not decrease after maximal expression at 4 h upon IL-4 stimulation. It is concluded that the Helper-1T-cell, type cytokine interferon gamma and the Helper-2 T-cell type cytokine interleukin-4 differentially regulate intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression on human lung fibroblasts. The proinflammatory cytokines interleukin-1beta and tumour necrosis factor alpha increase both intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression, without differential regulation of the expression of these adhesion molecules.

Cell Movement↗
PubMed1999

Peripheral blood T lymphocytes from asthmatic patients are primed for enhanced expression of interleukin (IL)-4 and IL-5 mRNA: associations with lung function and serum IgE.

BACKGROUND: The TH2-like cytokines interleukin (IL)-4 and IL-5 play a pivotal role in airway wall inflammation in asthma and these cytokines are increased in peripheral blood and bronchoalveolar lavage fluid from asthmatic patients. It is unclear why specifically TH2-like cytokines are increased in asthmatic patients. A possible explanation may be an impaired adenylyl cyclase activity, which has been observed in peripheral blood mononuclear cells of asthmatics. OBJECTIVE: To assess interferon (IFN)-gamma, IL-4 and IL-5 mRNA expressions and their control by prostaglandin E2 (PGE2), which activates adenylyl cyclases, of peripheral T lymphocytes from patients with moderately severe asthma and healthy controls. METHODS: Peripheral blood T lymphocytes from asthmatics and healthy controls were isolated and stimulated with antibodies against CD3 plus CD28 in the absence and presence of increasing concentrations of PGE2. IFN-gamma, IL-4 and IL-5 mRNA levels were detected by reverse transcription-polymerase chain reaction. RESULTS: In contrast to IFN-gamma mRNA, IL-4 (P = 0.03, n = 8) and IL-5 (P < 0. 05, n = 5) mRNAs in the asthma group were significantly higher than in controls (n = 4). In addition, IL-5 showed a significant inverse correlation with forced expiratory volume (FEV1) (P < 0.04, n = 5), whereas IL-4 positively correlated with PC20adenosine-monophosphate (AMP) (P < 0.02, n = 8). Accumulation of mRNA for IFN-gamma, IL-4 and IL-5 mRNA were significantly diminished by 10-5 m PGE2 in both asthmatics and controls. In contrast, 10-6 m PGE2 significantly down-regulated IFN-gamma and IL-4 mRNAs (P < 0.05 for both IFN-gamma and IL-4, n = 4) in the control group, whereas this was not observed for IL-4 mRNA in the asthma group (n = 7). CONCLUSIONS: Activated peripheral blood T lymphocytes from asthma patients display higher levels of IL-4 and IL-5 mRNA in vitro, which may be due to a diminished activity of adenylyl cyclase. A new observation is that higher IL-4 mRNA levels are associated with less severe AMP responsiveness, which might be due to a negative feedback loop of IL-4 production by mast cells.

Adult↗
PubMed1999

Allergen challenge primes for IL-5 mRNA production and abrogates beta-adrenergic function in peripheral blood T lymphocytes from asthmatics.

BACKGROUND: In previous studies, we have found a dysfunctional adenylyl cyclase (AC) system in patients with asthma after allergen provocation, which resulted in a 40-50% decreased generation of intracellular cAMP. In addition, in activated T helper lymphocyte clones, it has been demonstrated that IFN-gamma (TH1-like cytokine) and IL-5 (TH2-like cytokine) are differentially regulated by the AC system. Therefore, we postulate that an increased IL-5/IFN-gamma ratio as observed in asthmatics might be due to a dysfunctional AC system. OBJECTIVE: To assess whether a dysfunctional AC system as observed in asthmatics after allergen provocation, is responsible for an increased IL-5/IFN-gamma cytokine ratio. METHODS: Peripheral blood T lymphocytes of seven asthma patients were stimulated with anti-CD3 plus anti-CD28 MoAbs in the absence and presence of isoproterenol (ISO) and prostaglandin E2 (PGE2) to activate the AC system. Before, 3 h and 24 h after allergen provocation, IFN-gamma and IL-5 mRNAs were detected by semiquantitative RT-PCR. RESULTS: Before allergen provocation, ISO (10-5 mol/L) significantly downregulated IFN-gamma mRNA (P < 0.03, n = 6), and showed a trend to upregulate IL-5 mRNA (P = 0.138, n = 5). Three and 24 h after allergen provocation, ISO was not longer able to modulate IFN-gamma and IL-5. In contrast with the observations with ISO, PGE2 still dose-dependently inhibited IFN-gamma mRNA, both before, 3 h and 24 h after allergen provocation (n = 7). IL-5 mRNA, but not IFN-gamma mRNA, was significantly upregulated in anti-CD3 plus anti-CD28-activated T cells (P < 0.05, n = 5) 24 h after allergen provocation, compared with before allergen provocation. CONCLUSION: Twenty-four hours after allergen provocation, a significant reduction of beta-adrenergic control on IFN-gamma and IL-5 mRNA expression was observed in peripheral blood T lymphocytes, which coincides with a selective priming of IL-5 mRNA production.

Adenylyl Cyclases↗
PubMed1999

Interleukin-15 differentially enhances the expression of interferon-gamma and interleukin-4 in activated human (CD4+) T lymphocytes.

In this study interleukin (IL)-15 was examined for its ability to modulate the expression of interferon-gamma (IFN-gamma) and IL-4 in activated human T lymphocytes. The effect of IL-15 was compared with IL-2 and IL-7, cytokines all known to use the IL-2 receptor gammaC chain. The results demonstrate that the extent of upregulation of IFN-gamma and IL-4 mRNA was dependent on the applied cytokine (IL-2>IL-15>IL-7) and on the stimulatory signal. IFN-gamma and IL-4 mRNAs were upregulated by IL-15 in concanavalin A- (twofold) and anti-CD3 plus anti-CD28- (fivefold) stimulated T lymphocytes. IFN-gamma mRNA accumulation, but not IL-4 mRNA, was additively upregulated by IL-15 plus IL-7 (ninefold) in anti-CD3 stimulated T lymphocytes, and bypassed the requirement of CD28 signalling. Fluorescence-activated cell sorting (FACS) experiments demonstrated that IFN-gamma mRNA was upregulated by IL-15 in both CD4+ and CD8+ T lymphocytes, whereas IL-4 mRNA accumulation predominantly occurred in CD4+ cells. Preincubation of highly purified CD4+ T lymphocytes during 7 days with IL-15 and/or IL-7, followed by activation, also showed enhanced IL-4 protein secretion, but predominantly upregulated IFN-gamma protein. The net effect was a dramatically increased IFN-gamma/IL-4 ratio. Taken together, IL-15 and IL-7 can act as costimulatory signals, which may favour a T helper 1 (Th1) immune response, particularly in the absence of sufficient CD28 costimulation.

Antibodies↗
PubMed1999

Nitric oxide selectively decreases interferon-gamma expression by activated human T lymphocytes via a cGMP-independent mechanism.

The role of exogenous nitric oxide (NO) on the expression of interleukin (IL)-2, IL-4, IL-5 and interferon-gamma (IFN-gamma) by freshly isolated human T lymphocytes was investigated. The presence of NO, generated from any of the NO-donor compounds, S-nitroso-N-acetyl-D,L-penicillamine (SNAP), DPTA-nonoate (DPTA) or DETA-nonoate (DETA), added 15 min prior to T-cell stimulation (for 24 hr) with anti-CD3/anti-CD28 monoclonal antibodies (mAbs), resulted in up to 50% inhibition of IL-4, IL-5 and IFN-gamma secretion. In contrast, IL-2 secretion was not inhibited. Using the guanylate cyclase inhibitor, LY83583, it was shown that the inhibition of IL-4 and IL-5 was cGMP dependent, whereas additional mechanisms mediated the inhibition of IFN-gamma. Exposure of T cells to the NO-donor compounds for 24 hr prior to stimulation resulted in a more pronounced inhibition of IFN-gamma secretion by DPTA and DETA (P < 0.01), despite the fact that NO generation could no longer be detected. Under these conditions, IL-4 secretion was not inhibited and IL-5 secretion was inhibited to a lesser extent (P < 0.01 for SNAP and DPTA, P > 0.05 for DETA). IL-2 secretion was inhibited after 24 hr of preincubation with the NO-donor compounds, whereas it was not directly affected by NO. The increased inhibitory effects on IFN-gamma and IL-2 secretion could not be accounted for by the antiproliferative effects of the NO-donor compounds, which were diminished after 24 hr of preincubation relative to 15 min of preincubation. For IFN-gamma, the inhibition was at least partially effected at the transcriptional level as shown by decreased mRNA accumulation. These data show that NO can modulate the balance between the expression, by human T-lymphocytes, of T helper 1- and T helper 2-type cytokines, through selective and persistent inhibition of the expression of IFN-gamma via a cGMP-independent mechanism.

Aminoquinolines↗