Biomedical subjects

D Proud

Publications and source records attributed to D Proud.

At least 19 recordsLinked to original sources

PubMed1995

Expression of the chemokine RANTES by a human bronchial epithelial cell line. Modulation by cytokines and glucocorticoids.

The chemokine RANTES is a potent chemoattractant for eosinophils, lymphocytes, and monocytes, and has been detected recently in the epithelium of human airways mucosa. We have studied, therefore, the expression of RANTES mRNA and protein in the human bronchial epithelial cell line BEAS-2B. Using Northern blot analysis, RANTES mRNA was not detectable in unstimulated BEAS-2B cells. Incubation of cells with TNF-alpha or IFN-gamma induced the expression of RANTES mRNA and protein within 16 h. The combination of TNF-alpha and IFN-gamma displayed a marked synergism in inducing RANTES expression. Pretreatment of cells with the glucocorticoid budesonide (10(-10)-10(-7) M) for 24 h inhibited expression of RANTES mRNA and protein stimulated by either TNF-alpha or TNF-alpha plus IFN-gamma in a concentration- and time-dependent manner. Nonglucocorticoid steroids did not inhibit RANTES mRNA expression. Production of RANTES by epithelium could contribute to the mechanism of selective cellular recruitment occurring in the airways during inflammation, thus playing a relevant role in the pathogenesis of diseases such as asthma, rhinitis, and polyposis. The down-regulation of RANTES production by glucocorticoids in epithelial cells may contribute to the efficacy of these compounds in reducing cellular infiltration and, ultimately, to their anti-inflammatory properties.

Blotting, Northern↗

PubMed1995

Ozone exposure in humans: inflammatory, small and peripheral airway responses.

We exposed eight normal adults to filtered air (FA) and 0.35 ppm ozone (O3) and compared responses in spirometry, including isovolume (isoV) flows at intermediate-to-low lung volumes, against levels of inflammatory markers in bronchoalveolar lavage fluid (BALF) and peripheral lung resistance (Rp) measured through a wedged bronchoscope. Spirometry was performed at the end, 25 min and 24 h after exposure, bronchoscopy at 24 h after exposure. The percentages of neutrophils, fibrinogen, albumin, PGE2, PGF2 alpha, and kinins were elevated in BALF after O3 compared with FA. The percentage reduction in (isoV) FEF25-75 at 25 min and 24 h after administration of O3 correlated closely with the rise in fibrinogen concentrations in BALF, a marker of altered vascular permeability. Rp, a measurement dominated by very small or peripheral airways, was unaffected in 7 of 8 subjects. The absence of change in Rp might have reflected insufficient penetration of O3 into these airways to produce or sustain an effect for 24 h; alternatively, the bronchoscopic procedure which included atropine and lidocaine pretreatment may have reversed an O3 effect. An unexpected finding was the significant association between baseline Rp (after FA) and the magnitude of the spirometric response to O3. Our results suggest that small airway dysfunction in the immediate post-O3 period is a marker of lung inflammation.

Adult↗

PubMed1994

Glucocorticoids do not alter peptidase expression on a human bronchial epithelial cell line.

Respiratory epithelial cell surface neutral endopeptidase 24.11 (NEP-24.11) degrades proinflammatory peptides, and it has been suggested that glucocorticoids may reduce airway inflammation, in part, by upregulation of NEP-24.11. Despite the potential importance of the epithelium as a metabolic barrier, little is known regarding what other peptidases may be present on the epithelial cell surface. Using an immortalized bronchial epithelial cell line (BEAS-2B), we have shown that human epithelial cells express no detectable angiotensin-converting enzyme, carboxypeptidase N, or dipeptidyl(amino)peptidase IV, but express significant levels of aminopeptidase M (AmM), as well as NEP-24.11. The presence of these enzymes was demonstrated via their degradation of biologically active peptides and by flow cytometry. Exposure of cells to the glucocorticoid budesonide (10(-7) M) for up to 5 days did not markedly alter the expression of NEP-24.11 or AmM, as assessed by flow cytometry, nor did glucocorticoid treatment modify rates of peptide hydrolysis by NEP-24.11 or AmM. Thus, BEAS-2B cells have both AmM and NEP-24.11 on their surface, and expression of these enzymes is not altered by glucocorticoids.

Aminopeptidases↗

PubMed1992

Tryptase and histamine as markers to evaluate mast cell activation during the responses to nasal challenge with allergen, cold, dry air, and hyperosmolar solutions.

We have used assays for histamine and for the specific mast cell enzyme, tryptase, to examine the response of the nasal mucosa to provocation with several different stimuli and to evaluate the reliability of histamine as a marker of mast cell activation. High levels of histamine detected in baseline lavages of some subjects are not associated with any detectable tryptase, suggesting they are not mast cell derived. During pronounced immediate allergic responses, however, mast cell degranulation clearly occurs, and a striking correlation between histamine and tryptase is observed. This correlation is weaker when a more modest allergic response is induced, possibly reflecting differential diffusion of the two mediators across the epithelium. Provocation of susceptible individuals with cold, dry air leads to increased recoveries of both histamine and tryptase, confirming that mast cell degranulation occurs during this reaction. Although hyperosmolarity of the nasal mucosa may contribute to mast cell degranulation induced by cold, dry air, a brief exposure of the nasal cavity to hyperosmolar mannitol was not associated with measurable production of tryptase. The combined use of histamine and tryptase measurements can therefore provide useful evidence regarding the role of mast cell activation in the pathogenesis of inflammatory responses.

Adult↗

PubMed1992

Intranasal beclomethasone inhibits antigen-induced nasal hyperresponsiveness to histamine.

To determine whether intranasal steroid treatment inhibits the increased sensitivity to histamine that occurs 24 hours after nasal antigen challenge, 12 allergic volunteers were entered into a double-blind study comparing placebo or 164 micrograms of beclomethasone dipropionate twice a day for 7 days. Beclomethasone dipropionate partially reduced the early mediator response to antigen and the influx of eosinophils 24 hours later. Comparing the initial histamine challenge with that done 24 hours after antigen with the subjects on placebo, there was a significant increase in sneezes, TAME-esterase activity, and albumin. Pretreatment with intranasal beclomethasone dipropionate resulted in a reduced response to histamine 24 hours after antigen challenge. A positive correlation occurred between the number of eosinophils in the lavage before histamine challenge and the level of TAME-esterase activity (rs = 0.67, p = 0.03) during the histamine challenge that followed antigen with the subjects on placebo. We thus confirmed the increase in nonspecific nasal airway responsiveness 24 hours after antigen challenge, with a concomitant increase in eosinophils, and demonstrate its inhibition by pretreatment with intranasal steroids.

Administration, Intranasal↗

PubMed1992

The nasal response to histamine challenge: effect of the pollen season and immunotherapy.

To evaluate changes in the nasal response to histamine, we challenged 19 subjects with allergic rhinitis caused by ragweed (RW) before, during, and after the RW season with increasing doses of histamine diphosphate. We compared their response, as measured by symptoms and the levels of TAME-esterase activity and albumin recovered in the nasal lavage fluid, with response of two groups with allergic rhinitis undergoing immunotherapy with moderate-dose (N = 16) and high-dose (N = 11) RW (2 and 24 micrograms of antigen E [Amb a I] as maintenance dose, respectively). Four challenges with histamine were performed in each group: before, at the peak of, near the end of, and 2 weeks after the RW season. The three groups of subjects had similar skin sensitivity to antigen and levels of TAME-esterase activity and albumin recovered from nasal lavages after histamine challenge performed before seasonal exposure. Symptom diaries obtained throughout the season revealed a significant reduction only in the high-dose immunotherapy-treated group. At the peak of the season, the untreated group had more symptoms in response to the challenge compared with the challenges before and after the season (p = 0.04 for both groups). The saline challenge occurring before challenging with histamine also demonstrated a significant increase at the peak of the season compared with increases before the season (p = 0.02). This observation was also true for the levels of albumin and TAME-esterase activity. If the response after saline challenge was subtracted from each response after histamine challenge, no difference was found in the results between any of the visits.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

The effect of azelastine on the early allergic response.

To study the effect of azelastine on the immediate reaction to nasal allergen challenge, we performed a double blind, placebo-controlled cross-over clinical trial. Thirteen subjects with seasonal allergic rhinitis underwent nasal challenge with antigen 4 hr after a single oral 2 mg dose of azelastine. The response was monitored by counting the number of sneezes and by measuring the levels of histamine, prostaglandin D2, immunoreactive sulphidopeptide leukotrienes, kinis and TAME-esterase activity in recovered nasal lavages. After a single dose of azelastine, there was a significant reduction in sneezing (10 vs 2, P = 0.01) and in the median levels of recovered TAME-esterase activity (63.1 vs 17.5 c.p.m. x 10(-3), P = 0.01), immunoreactive sulphidopeptide leukotrienes (7.5 vs 2.1 ng/ml, P = 0.03) and kinins (1370 vs 251 pg/ml, P = 0.03), with no significant reduction in the median levels of histamine (3.7 vs 1.2 ng/ml, P = 0.2) and prostaglandin D2 (70 vs 70 pg/ml, P = 0.2) compared to placebo (numbers represent total increase over diluent challenge). These results suggest that azelastine does not inhibit mast cell activation but affects the consequences of released histamine, namely sneezing, increased vascular permeability and the generation of kinins. The results further suggest that other cells, in addition to mast cells, might be responsible for the generation of leukotrienes during the early allergic response, and that azelastine reduces their ability to generate this mediator or that inhibition of leukotriene release from mast cells occurs at lower drug concentrations.

Adult↗

PubMed1992

Platelet activation in the lung after antigen challenge in a model of allergic asthma.

The purpose of this study was to investigate whether platelets are activated and release their products in the human lung after antigen challenge. Using subsegmental antigen challenge as a model of asthma, bronchoalveolar lavage fluids from ragweed-allergic asthmatic subjects were assayed for the alpha granule products, platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG), prior to challenge (baseline) and at 5 min and 19 h after challenge with ragweed antigen. Airway segments challenged with normal saline were used as controls. Five minutes after antigen challenge, levels of platelet products in BAL fluid were not elevated from baseline or normal saline control levels. However, 19 h after antigen challenge, a 10-fold increase in platelet products in BAL fluids was found. The mean PF4 levels increased from baseline and saline control values of less than 1.0 to 7.2 ng/ml (p less than 0.05) 19 h after antigen challenge. beta-TG increased from baseline and control levels of less than 1.0 to 6.6 ng/ml (p less than 0.05). Elevations in PF4 and beta-TG were highly correlated with each other (r = 0.98, p less than 0.0001). Levels of platelet products during the 19-h response correlated with albumin, with kinins, with the prostaglandins 6-keto-PGF1 alpha, PGE2, and PGF2 alpha, and with the eosinophil-derived proteins, eosinophil-derived neurotoxin and eosinophil peroxidase. We conclude that platelet activation in the lung is a feature of the late inflammatory response to antigen challenge and that platelets may play an important role in allergic inflammation and asthma.

Adult↗

PubMed1992

Elevation of tissue kallikrein and kinin in the airways of asthmatic subjects after endobronchial allergen challenge.

Bronchial tissue kallikrein is the major kininogenase activity in the airways of asthmatic subjects. The relationship of IgE-mediated events to its release and/or activation is unknown, however, and is the subject of this report. Seven subjects with mild atopic asthma underwent endobronchial challenge with relevant aeroallergen. Baseline pre-allergen lavage and sequential post-challenge lavages were collected over an approximate 10-minute time course. Individual aliquots were analyzed separately and compared with saline control lavages performed in a separate lobe. In five of the seven subjects, an increase in tissue kallikrein activity, measured by cleavage of the synthetic substrate Val-Leu-Arg-pNA, was identified in the post-challenge lavages. The antigenic identity of the enzymatic activity was confirmed as a tissue kallikrein in each case by immunoblotting. Tissue kallikrein activity was highly correlated with the appearance of immunoreactive histamine and kinin (p = 0.0001). High molecular weight kininogen influx and cleavage was detected in the post-challenge samples by immunoblotting and paralleled the detection of kinin in BAL fluid. Two of the subjects, despite clinical profiles similar to those of the five positive responders, failed to react to endobronchial challenge. Saline control lavages contained detectable kallikrein, kinin, and histamine in two subjects; in each case, however, this was significantly less than in the post-allergen samples. The results demonstrate a close association between immediate type hypersensitivity events in the lower airway and the appearance of active kallikrein, kininogen substrate, and the liberation of kinin.

Adult↗

PubMed1992

Local application of atropine attenuates the upper airway reaction to cold, dry air.

In some individuals, inhalation of cold, dry air (CDA) provokes symptoms of rhinitis, accompanied by an increase in the levels of inflammatory mediators and markers of plasma leakage of recovered nasal lavages. Because rhinorrhea is a major component of this reaction and because nasal glands are heavily innervated by the parasympathetic system, we assessed the effect of atropine on the nasal reaction to CDA. Using a double-blind, randomized, crossover design, we administered a total dose of 0.5 mg of atropine or placebo intranasally to 18 volunteers before provocation with CDA. The reaction was monitored with symptom scores and by measuring the concentrations of histamine, N-alpha-p-tosyl-L-arginine methyl ester (TAME)-esterase activity and albumin, as well as the osmolality of lavage fluids before and after the provocation. Atropine significantly reduced rhinorrhea, the levels of histamine, and TAME-esterase activity as well as the osmolality of recovered lavage fluids, but had no effect on nasal congestion or albumin. Even with atropine, however, rhinorrhea and TAME-esterase activity were still significantly increased over the prechallenge baseline. Our results demonstrate that atropine-sensitive parasympathetic efferent pathways contribute to the CDA-induced rhinitis. We speculate that (1) the glandular and the vascular events of the upper airway reaction to dry air have different pathophysiologic mechanisms; (2) a significant component of TAME-esterase activity in lavage fluids may be of glandular origin; and (3) in addition to parasympathetic nerve activation, other mechanisms are involved in the upper airway reaction to dry air. The mechanism(s) leading to the reduction of histamine is unknown.

Administration, Intranasal↗

PubMed1992

Cultured human synovial fibroblasts rapidly metabolize kinins and neuropeptides.

Kinins and substance P have been implicated in the pathogenesis of inflammatory arthritis by virtue of their abilities to induce vasodilation, edema, and pain. The relative biological potencies of these peptides in vivo would depend at least in part upon their rates of catabolism in the joint. We hypothesized that human synovial lining cells may regulate intraarticular levels of kinins and neuropeptides via degradation by cell surface-associated peptidases. We exposed intact human synovial fibroblasts to kinins and substance P, in the presence or absence of specific peptidase inhibitors, and measured the amount of intact substrate remaining and degradation product(s) generated over time. Aminopeptidase M (AmM; EC 3.4.11.2), neutral endopeptidase-24.11 (NEP-24.11; EC 3.4.24.11), and dipeptidyl(amino)peptidase IV (DAP IV; EC 3.4.14.5) were identified on the cell surface of synovial cells. Bradykinin degradation was due entirely to NEP-24.11 (1.39 +/- 0.29 nmol/min per well). Lysylbradykinin was also degraded by NEP-24.11 (0.80 +/- 0.19 nmol/min per well); however, in the presence of phosphoramidon, AmM-mediated conversion to bradykinin (3.74 +/- 0.46 nmol/min per well) could be demonstrated. The combined actions of NEP-24.11 (0.93 +/- 0.15 nmol/min per well) and DAP IV (0.84 +/- 0.18 nmol/min per well) were responsible for the degradation of substance P. AmM (2.44 +/- 0.33 nmol/min per well) and NEP-24.11 (1.30 +/- 0.45 nmol/min per well) were responsible for the degradation of the opioid peptide, [Leu5]enkephalin. The identity of each of the three peptidases was confirmed via synthetic substrate hydrolysis, inhibition profile, and immunological identification. The profiles of peptidase enzymes identified in cells derived from rheumatoid and osteoarthritic joints were identical. These data demonstrate the human synovial fibroblast to be a rich source of three specific peptidases and suggest that it may play a prominent role in regulating peptide levels in the joint.

Antigens, CD↗

PubMed1992

Evaluation of a bedtime dose of a combination antihistamine/analgesic/decongestant product on antigen challenge the next morning.

The effects of CAAD (diphenhydramine hydrochloride, 50 mg; pseudoephedrine hydrochloride, 60 mg; acetaminophen, 1 g in 10% ethanol) were evaluated in a double-blind, three-way, placebo-controlled, cross-over study on 18 volunteers with allergic rhinitis. The number of sneezes following nasal challenge with antigen was significantly reduced after a bed-time dose of CAAD (P less than .005) and a single dose of diphenhydramine (P less than .001) given 2 hours before the challenge. The levels of N-alpha-tosyl-L-arginine methyl ester (TAME) activity decreased after diphenhydramine treatment, while histamine levels following challenge were not different. The drowsiness reported after CAAD was equal to placebo, but significantly less than diphenhydramine (P less than .002 for both). The active treatments reduced the actions of histamine without suppressing its release from mast cells. The effect of CAAD persists 10 hours after administration without inducing drowsiness.

Acetaminophen↗

PubMed1992

Characterization of kinin receptors on human synovial cells and upregulation of receptor number by interleukin-1.

Bradykinin has been implicated in the pathogenesis of inflammatory arthritis by virtue of its potent proinflammatory properties. We have previously shown bradykinin to be a potent stimulus for the release of prostanoids from interleukin-1 (IL-1)-treated, but not untreated, human synovial cells. We hypothesize that one mechanism by which IL-1 induces responsiveness to bradykinin is by upregulation of number or affinity of kinin receptors on human synovial cells. We performed [3H]bradykinin binding studies in intact human synovial tissue and in cultured human synovial cells. Specific, saturable [3H]bradykinin binding sites in intact synovia were identified by autoradiographic localization and were present in much higher density in rheumatoid, than in osteoarthritis, synovia. In untreated human synovial cells in culture, a single (B2) class of kinin binding sites with a Kd of 2.3 nM and Bmax of 58 +/- 9 fmol/10(6) cells was demonstrated. In matched experiments, IL-1 treatment enhanced specific [3H]bradykinin binding 1.5- to 2.0-fold above that observed in untreated cells. This enhancement was attributable to an increase in Bmax (53 +/- 4 vs. 105 +/- 24 fmol/10(6) cells in untreated and IL-1-treated cells, respectively), rather than an alteration in Kd (1.7 and 1.4 nM, respectively). The potencies of a series of kinin analogs and antagonists and unrelated peptides in displacing [3H]bradykinin from IL-1-treated cells correlated well with their abilities to induce prostanoid release. These studies provide novel information regarding the nature of kinin receptors in intact human synovia and in cultured human synovial cells, their regulation by IL-1 and their role in IL-1-treated cells in kinin-mediated prostaglandin E2 production.

Autoradiography↗

PubMed1992

Modulation of kinin responses in human synovium by interleukin-1.

Bradykinin (BK) is a weak stimulus for prostaglandin E2 (PGE2) release in untreated human synovial cells, but a potent stimulus in interleukin-1 (IL-1) pretreated cells. The mechanism(s) by which IL-1 induces responsiveness of synovial cells to BK appears to be multifactorial. IL-1 not only upregulates the number of kinin receptors on these cells, but may also upregulate a calcium-dependent process involved in the synthesis of prostaglandins.

Arthritis, Rheumatoid↗

PubMed1992

Production of granulocyte-macrophage colony-stimulating factor by cultured human tracheal epithelial cells.

We have evaluated the capacity of cultured human respiratory epithelial cells (HTE) to produce granulocyte-macrophage colony-stimulating factor (GM-CSF) and have examined the ability of proinflammatory stimuli and of glucocorticoids to modulate the production of GM-CSF by these cells. Conditioned medium (CM) was obtained after 24-hr culture of HTE in the presence or absence of serum (5%) and was assayed for GM-CSF activity using the M-07e cell line, which proliferates in response to GM-CSF and interleukin-3 (IL-3). HTE produced 1.1 +/- 0.7 and 2.1 +/- 1.5 ng GM-CSF/10(6) cells in the presence or absence of serum, respectively (n = 4). The identity of this activity as GM-CSF was established by neutralization with specific antibody to GM-CSF, while antibody to IL-3 was without effect. Dexamethasone (10(-6) M) inhibited basal GM-CSF release to below the limit of detection of the assay (0.12 ng GM-CSF/ml conditioned media). GM-CSF release was significantly enhanced by 10(-6) M histamine (1.6 +/- 0.7 versus 2.13 +/- 0.8 ng GM-CSF/10(6) cells; n = 9) and 5 ng/ml interleukin-1 (IL-1) (0.6 +/- 0.2 versus 3.2 +/- 0.5 ng GM-CSF/10(6) cells; n = 3). Stimulation of GM-CSF release by IL-1 was dose-dependent. A significant increase in GM-CSF activity was observed with 0.1 ng/ml, while maximal stimulation occurred at 5 ng/ml IL-1. In kinetic studies, GM-CSF activity was first detected in CM from cells incubated in the absence of stimulus at 8 hr of incubation, and continued to increase up to 24 hr. IL-1 stimulated GM-CSF activity was detected in CM as early as 4 hr and continued to increase significantly up to 24 hr. Thus, human tracheal epithelial cells release GM-CSF and this release is regulated by inflammatory mediators and glucocorticoids.

Adult↗

PubMed1991

Interaction of platelet-activating factor with cultured guinea pig tracheal epithelial cells.

The present study has examined the interaction of platelet-activating factor (PAF) with cultured guinea pig tracheal epithelial cells (GTE). PAF stimulated GTE to release endogenous arachidonic acid and metabolize it to prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha). Prostanoid production by GTE in response to PAF was dose-dependent (0.1-100 nM) and was maximal within 5 min. PGE2 and PGF2 alpha levels increased by 3.3 +/- 0.8 and 3.2 +/- 0.6 ng/10(6) cells respectively over basal levels in response to 100 nM-PAF. The ability of GTE to synthesize and/or catabolize PAF was also examined. GTE readily incorporated [3H]acetate into a product which migrated on t.l.c. with PAF. However, further characterization of this product suggested that label had not been incorporated into PAF, but rather that it was incorporated into another lipid product with chromatographic characteristics similar to those of PAF. In contrast, GTE readily metabolized PAF to inactive products. When [3H]PAF was incubated with GTE, 50% of the total [3H]PAF added was catabolized in approx. 15 min. The major route of catabolism of PAF by GTE was the deacetylation-reacylation pathway, which yielded 1-O-[3H]alkyl-2-acyl-sn-glycerophosphocholine. Determination of the nature of the long-chain acyl group incorporated into the sn-2 position of the newly synthesized products revealed that oleic and linoleic acids were the major fatty acids present. Taken together, these results suggest that respiratory epithelial cells respond to stimulation by PAF with enhanced production of PGE2 and PGF2 alpha, and also have the capacity to modulate inflammatory reactions in the airways by their ability to degrade this potent inflammatory mediator.

Animals↗

PubMed1991

Mechanisms of mediator release from human skin mast cells upon stimulation by the bradykinin analog, [DArg0-Hyp3-DPhe7]bradykinin.

We have used the bradykinin analog, [DArg0-Hyp3-DPhe7]-bradykinin, as a model stimulus with which to examine peptide-induced mediator release from human skin mast cells (SMC) and to compare it with IgE-mediated release from the same cells. The bradykinin analog was an effective histamine secretagogue, inducing a comparable maximal level of release to that observed for anti-IgE. By contrast to anti-IgE, however, [DArg0-Hyp3-DPhe7]-bradykinin did not stimulate marked release of prostaglandin D2 (PGD2) from these cells. In experiments where cells were exposed to both stimuli simultaneously, histamine release was additive, while PGD2 release was the same as that observed for anti-IgE alone. The kinetics of [DArg0-Hyp3-DPhe7]-bradykinin-stimulated histamine release were rapid, with 50% of maximal release being achieved within 30 sec, compared to 2-3 min for anti-IgE. Interestingly, when both stimuli were applied simultaneously, the kinetics of release were intermediate between those of either stimulus alone. Studies of the signal transduction pathways that may be involved in [DArg0-Hyp3-DPhe7]-bradykinin-induced histamine release revealed striking differences to results obtained with anti-IgE. While agents that increase intracellular cyclic AMP have a pronounced inhibitory effect on IgE-mediated release, forskolin, isobutylmethylxanthine and isoproterenol were all totally ineffective at inhibiting histamine release induced by the bradykinin analog. Similarly, staurosporine, a relatively selective inhibitor of protein kinase C, and the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA) an activator of this enzyme, both have pronounced effects on IgE-mediated histamine release from SMC but were completely inactive with regard to [DArg0-Hyp3-DPhe7]-bradykinin-stimulated release. SMC stimulated with this peptide showed characteristic changes in intracellular free calcium levels, as assessed by digital video microscopy. This response differs from that induced by anti-IgE in that it had a more rapd onset, achieved a lower peak, and decayed much more rapidly. Analysis at the single cell level showed that cells that responded in this fashion upon exposure to the bradykinin analog were capable of showing an additional response upon subsequent exposure to anti-IgE. We conclude that histamine release from SMC in response to [DArg0-Hyp3-DPhe7]-bradykinin occurs via a completely different mechanism from that in response to IgE-mediated stimuli. Peptide-induced release is rapid and is not susceptible to pharmacologic manipulation of intracellular cyclic AMP or protein kinase C but utilizes a rapid transient shift in intracellular calcium concentrations as part of its signal transduction pathway.

Antibodies, Anti-Idiotypic↗

PubMed1991

Effects of immunotherapy on the early, late, and rechallenge nasal reaction to provocation with allergen: changes in inflammatory mediators and cells.

We investigated the effects of immunotherapy (IT) on the early (ER), late (LPR), and rechallenge reactions (RCRs) to nasal challenge with antigen as well as on the cutaneous ER and LPR to intradermal skin challenge. Our expectation was that IT would have a preferential effect on the LPR, and our aim was to understand the mechanism. Twenty-one ragweed hay fever-sensitive subjects were treated with a moderate dose of antigen extract (maintenance dose of 1.94 micrograms of antigen E (Amb a I)) during a period of 8 months (total dose equivalent to 24 micrograms of antigen E), and 20 matched subjects received placebo injections in a double-blind manner. Both groups underwent identical nasal challenges and intradermal skin tests with ragweed-antigen extract both before (1985) and during (1986) IT. Symptom and medication diaries, recorded during seasonal exposure, and changes in specific serum IgE and IgG antibodies confirmed the efficacy of the administered IT dose. Between-group analysis revealed that IT significantly reduced the levels of histamine, TAME-esterase activity, and kinins, as well as symptoms of rhinorrhea and congestion generated during the ER to nasal challenge. Within-group paired analysis demonstrated ER, LPR, and RCR mediators and symptoms also to be reduced by IT. Surprisingly, the placebo-treated group demonstrated an increase in the ER. There was no decrease of the LPR without an antecedent decrease of the ER. IT did not clearly change the late cellular inflammatory response. In the case of skin challenge, IT significantly reduced the cutaneous ER. The reduction of the cutaneous LPR was more pronounced. We speculate that moderate-dose IT ameliorates seasonal symptoms of allergic rhinitis by reducing the ER, LPR, and RCR to antigen challenge but does not preferentially reduce the nasal LPR.

Allergens↗