Effect of interleukin-5 exposure during in vitro eosinophilopiesis on MAC-1 adhesion molecule expression and function on cultured human eosinophils

We examined the selective effects of interleukin (IL-5) in regulating the maturational expression of surface adhesion molecules on human eosinophils and adhesion to endothelial cells during eosinophiiopolesis in vitro. Expression of the beta 2 integrins (CD11/CD18) and the beta 1 integrin, VLA-4 (CD49d/ CD29), was assessed during development in culture with IL-3, IL-5, and granulocyte-macrophage colony stimulating factor in cultures of human umbilical cord blood-derived eosinophil (CDE) precursor cells. Expression of both CD11b and CD18 subunits of Mac-1 was lower on CDE which were continuously (= chronically) exposed to IL-5 than on CDE which were cultured without IL-5 for the final week of culture. CD11b expression on cells grown without IL-5 was 71.3 +/- 5.92 (mean specific fluorescence value [MSF] as measured by flow cytometry) versus 52.5 +/- 4.48 MSF for Mac-1 alpha (CD11b) on CDE grown in the continued presence of 2 x 10 - 11 mol/L IL-5 (P < .01). Although expression of VLA-4 decreased as CDE matured, expression of CD29 and CD49d were similar regardless of cytokine exposure for the final week of culture. For eosinophils cultured without IL-5, acute stimulation with 10 - 8 mol/L IL-5 increased CD11b surface expression and increased the number of cells adhering to unstimulated human umbilical vein endothelial cells (HUVEC) from 4,570 +/- 780 cells (9.14 +/- 1.56% adhesion) to 8,385 +/- 515 cells (16.8 +/- 1.03% adhesion) (P < .01). Basal adhesion to unstimulated HUVEC of CDE cultured continuously with IL-5 was comparable (8.62 +/- 1.12% adhesion; P = NS), but neither CD11b expression (50.3 +/- 11.8 MSF; P = NS v control) nor adhesion to HUVEC (6.77 +/- 1.35%; P = NS) was enhanced in these eosinophils after acute stimulation with IL-5. Blockade of adhesion to IL-1-stimulated HUVEC caused by the anti-CD49d monoclonal antibody (MoAb), HP2/1, was comparable for cells cultured with IL-5 and without IL-5. However, the anti-CD18 MoAb, R15.7, caused 47.6 +/- 5.08% inhibition of adhesion of eosinophils cultured without IL-5 and only 25.8 +/- 5.20% for cells cultured continuously with IL-5 (P < .01), and failed to block significantly the adhesion of only the latter cells to IL-4-stimulated HUVEC. Our data show that continuous, chronic exposure to low concentrations of IL-5 causes decreased expression of Mac-1 and refractoriness to acute stimulation with IL-5 of adhesion to HUVEC. These data further demonstrate that CDE maturing in the continued presence of IL-5 adhere to HUVEC predominantly through VLA-4 ligation.

Eosinophil VLA-4 binding to fibronectin augments bronchial narrowing through 5-lipoxygenase activation

We examined the effect of ligation of human eosinophils activated by platelet-activating factor (PAF) to soluble human fibronectin (FN) on the augmented contractile response of human bronchial explants. Styrene microplate wells were FN-coated and eosinophils were allowed to adhere in the presence of 1) buffer control, 2) 20 micrograms/ml monoclonal antibody (HP2/1) to the alpha 4 beta 1 ligand (VLA-4) on the eosinophils, 3) 20 micrograms/ml anti-CD18 R15.7, 4) 20 micrograms/ml anti-CD16 3G8, or 5) 10(-6) M A63162, a 5-lipoxygenase inhibitor. Sixty minutes later, treated cells were activated with either buffer or 10(-6) M PAF. Airway luminal diameter was assessed by computerized videomicrometry as a function of pixel number, and activation of eosinophils was confirmed by measurement of leukotriene C4 (LTC4) secretion. Ligation with FN caused an increase in PAF-stimulated LTC4 secretion from 276 +/- 75.6 pg/10(6) cell at baseline to 606 +/- 90.2 pg/10(6) cell (P < 0.01). This corresponded to augmented luminal narrowing of human bronchial explants from 25.3 +/- 9.39% (PAF activation alone) to 42.9 +/- 8.0% (PAF-activated eosinophils + FN) (P < 0.01). Both augmented airway luminal narrowing and increased LTC4 secretion caused by PAF-activated cells after FN ligation were blocked completely by anti-VLA-4 MAb (P < 0.05 vs. control). Pretreatment with 10(-6) MA63162 inhibited completely the PAF-stimulated LTC4 secretion to baseline level ( P < 0.001). Inhibition of 5-lipoxygenase similarly blocked luminal narrowing caused by eosinophils stimulated by PAF by > 95% (P < 0.001). We demonstrate that the binding of human eosinophils to the matrix protein FN causes augmented secretion of LTC4 which, in turn, causes augmented luminal narrowing of explanted human bronchi in vitro. We also demonstrate that the augmented activity is blocked selectively by pretreatment with specific monoclonal antibody against VLA-4 and blockade of eosinophil 5-lipoxygenase inhibits both LTC4 secretion and airway narrowing after PAF-stimulation.

Mechanisms of smooth muscle contraction elicited by cationic proteins in guinea pig trachealis

Cationic proteins elicit contraction of airway smooth muscle, but the mechanisms by which this occurs are not completely understood. We studied potential mechanisms by which eosinophil major basic protein (MBP) and the synthetic cationic proteins poly-L-lysine (PL) and poly-L-arginine (PA) cause contraction of isolated guinea pig tracheal smooth muscle (TSM) in vivo. Topical application of 10(-8) mol/cm2 of each protein to an isolated tracheal segment elicited TSM contraction with potency PL > MBP > PA. Pretreatment with atropine blocked the subsequent response to MBP but did not block the response to either PL or PA. Pretreatment with indomethacin blocked the subsequent response to both MBP and PL but did not block the response to PA. We demonstrate that MBP causes contraction of guinea pig TSM both through stimulation of the parasympathetic nervous system and secretion of a cyclooxygenase mediator. Neither PL nor PA, while of similar molecular weight and charge as MBP, cause TSM contraction via the parasympathetic nervous system, though some cationic proteins may act via a prostanoid mediator. Thus the cationic charge of MBP is not solely responsible for its effects on TSM in the guinea pig.

Differential tachykinin receptor subtype activation in capsaicin and KCl contractions of guinea pig trachealis

We assessed the role of endogenously secreted tachykinins in mediating contraction caused by potassium chloride (KCl) in guinea pig tracheal smooth muscle (TSM) strips in vitro. Maximal isometric contraction was elicited with approximately 45 mM KCl and was 196 +/- 8% of the response to electrical field stimulation (% EFS) in the same tissues. Muscarinic receptor blockade with atropine modestly attenuated this contraction caused by KCl to 175 +/- 9 %EFS (P < 0.05), and treatment with a selective neurokinin subtype 1 (NK1) receptor antagonist, LY-297911, caused even greater inhibition of KCl-elicited contraction to 124 +/- 8 %EFS (P < 0.001). By contrast, SR-48968, a selective NK2 antagonist, had no effect on contraction caused by KCl (183 +/- 9 %EFS; P = NS vs. KCl alone). However, given together at the same concentration, SR-48968 augmented the inhibition of contraction caused by LY-297911 to 93 +/- 15 %EFS (P < 0.05 vs. LY-297911 alone). In contrast to the effect on KCl-induced contraction, LY-297911 caused only moderate inhibition of the contraction caused by capsaicin to 81 +/- 13 %EFS (P < 0.05 vs. control, 114 +/- 15 %EFS), whereas SR-48968 caused substantial attenuation of contraction caused by capsaicin to 23 +/- 5 %EFS (P < 0.005 vs. LY-297911). We demonstrate that a significant portion of the contraction caused by KCl, in addition to capsaicin, is elicited in guinea pig TSM through neurokinin secretion. However, NK1 receptors predominantly mediate contraction caused by KCl, and NK2 receptors predominantly mediate contraction elicited by capsaicin in guinea pig airway smooth muscle.

Bioactivity of recombinant feline interleukin-2 on human and feline leukocytes

Interleukin (IL)-2 is a 16,000 Da protein product of T lymphocytes which is the principle cytokine responsible for clonal expansion of T lymphocytes as a response to antigen exposure. Deficiency of functional IL-2 plays a pivotal role in the pathogenesis of human immunodeficiency syndrome and may be important in the pathogenesis of feline immunodeficiency syndrome as well. Additionally, IL-2 may enhance secretion of interleukin-5 from the TH2 subset of CD4+ T cells, promote peripheral and systemic eosinophilia, and contribute to the eosinophilia which characterizes the inflamed airways of human beings and cats with asthma. We recently reported the sequence of feline IL-2 and the synthesis of recombinant feline IL-2. The purpose of the present study was to evaluate the bioactivity of recombinant feline IL-2 on human and feline leukocytes. We established dose-response relationships between recombinant feline IL-2 and radiolabeled proliferating human and feline leukocytes using thymidine incorporation as a marker of bioactivity. We found that recombinant human IL-2 promotes proliferation of both human and feline leukocytes. However, recombinant feline IL-2 promotes proliferation of feline cells, but not human cells.

Paradoxical blockade of beta adrenergically mediated inhibition of stimulated eosinophil secretion by salmeterol

Salmeterol (SALM) is a long-acting beta 2 adrenoceptor agonist that causes prolonged relaxation of airway smooth muscle. To determine whether this agent also causes prolonged inhibition of stimulated eosinophil secretion, we studied interactions between SALM and albuterol (ALB) in inhibiting eosinophil peroxidase (EPO) secretion in human eosinophils in vitro. Peripheral blood eosinophils were isolated from 18 human volunteers by negative immunoselection, and secretion of EPO was elicited with 10(-6) M formyl-met-leu-phe (fMLP) + 5 micrograms/ml cytochalasin B (CytB) in aliquots of 10(5) cells. Eosinophils were pretreated with either 10(-8) M ALB, 10(-8) M SALM or SALM + ALB for 5 min to 18 hr at 37 degrees C. Pretreatment with ALB for 5 min caused inhibition of stimulated secretion of EPO to 783 +/- 210 ng/10(6) cells vs. 1475 +/- 286 ng/10(6) cells for eosinophils not treated with ALB (P < .05; n = 5). Inhibition of EPO secretion caused by ALB was sustained for 30 min (924 +/- 160 ng/10(6) cells; P < .05 vs. fMLP + CytB; n = 5). By contrast, SALM had no inhibitory effect on fMLP-induced secretion after incubation for 5 min to 18 hr. In cells obtained from four separate isolations, pretreatment with 10(-8)M SALM before addition of ALB blocked the inhibition of EPO release caused by 10(-8)M ALB alone (486 +/- 28 ng/10(6) cells for ALB alone vs. 902 +/- 32 ng/10(6) cells for SALM + ALB; P < .01; n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Hyaluronic acid enhances cell proliferation during eosinopoiesis through the CD44 surface antigen

We examined the effect of hyaluronic acid in promoting proliferation of undifferentiated progenitor cells through the CD44 receptor during eosinopoiesis in vitro. Undifferentiated umbilical cord blood cells were purified on the first day to isolate primitive progenitor cells expressing the CD34 hemopoietic surface marker. Culture in wells coated with 100 micrograms/ml hyaluronic acid caused a 198 +/- 28.7% augmentation of proliferation of CD34+ progenitor cells at 3 wk (p < 0.01). By contrast, concentrations of hyaluronic acid > 10 micrograms/ml inhibited proliferation of unfractionated cord blood mononuclear cells. The augmented proliferation of precursor cells caused by hyaluronic acid was associated with complete (93.0 +/- 5.12%) differentiation to eosinophil morphology. By contrast, concentrations of hyaluronic acid > or = 10 micrograms/ml inhibited eosinophilic differentiation of unfractionated mononuclear cells. Wright-Giemsa staining demonstrated 95.4 +/- 2.92% eosinophils for CD34+ cells cultured for 3 wk without hyaluronic acid (control) and 93.8 +/- 5.11% for CD34+ cells cultured in hyaluronic acid-coated wells (100 micrograms/ml); for unfractionated cells, 94.0 +/- 3.02% demonstrated eosinophilic morphology in control wells at 3 wk vs 55.4 +/- 8.34% in hyaluronic acid-coated (100 micrograms/ml) wells (p < 0.05). Augmented proliferation caused by hyaluronic acid was attenuated completely by the anti-CD44 mAbs, 212.3 and IM7.8.1. Pretreatment of CD34+ cells with 5 micrograms/ml 212.3 inhibited the augmented proliferation caused by the optimal concentration of hyaluronic acid (100 micrograms/ml) from 260 +/- 39.2% of control growth to 114 +/- 16.4% of control growth (p = 0.02). Inhibition was comparable for IM7.8.1. Control mAb (LM2) to the beta 2 integrin subunit CD11b had no effect on proliferation induced by hyaluronic acid. We demonstrate that hyaluronic acid stimulates the growth of CD34+ selected umbilical cord blood cells into specifically differentiated mature eosinophils. This process is modulated by the CD44 receptor on the progenitor cell population.

Hyaluronic acid enhances cell proliferation during eosinopoiesis through the CD44 surface antigen

We examined the effect of hyaluronic acid in promoting proliferation of undifferentiated progenitor cells through the CD44 receptor during eosinopoiesis in vitro. Undifferentiated umbilical cord blood cells were purified on the first day to isolate primitive progenitor cells expressing the CD34 hemopoietic surface marker. Culture in wells coated with 100 micrograms/ml hyaluronic acid caused a 198 +/- 28.7% augmentation of proliferation of CD34+ progenitor cells at 3 wk (p &lt; 0.01). By contrast, concentrations of hyaluronic acid &gt; 10 micrograms/ml inhibited proliferation of unfractionated cord blood mononuclear cells. The augmented proliferation of precursor cells caused by hyaluronic acid was associated with complete (93.0 +/- 5.12%) differentiation to eosinophil morphology. By contrast, concentrations of hyaluronic acid &gt; or = 10 micrograms/ml inhibited eosinophilic differentiation of unfractionated mononuclear cells. Wright-Giemsa staining demonstrated 95.4 +/- 2.92% eosinophils for CD34+ cells cultured for 3 wk without hyaluronic acid (control) and 93.8 +/- 5.11% for CD34+ cells cultured in hyaluronic acid-coated wells (100 micrograms/ml); for unfractionated cells, 94.0 +/- 3.02% demonstrated eosinophilic morphology in control wells at 3 wk vs 55.4 +/- 8.34% in hyaluronic acid-coated (100 micrograms/ml) wells (p &lt; 0.05). Augmented proliferation caused by hyaluronic acid was attenuated completely by the anti-CD44 mAbs, 212.3 and IM7.8.1. Pretreatment of CD34+ cells with 5 micrograms/ml 212.3 inhibited the augmented proliferation caused by the optimal concentration of hyaluronic acid (100 micrograms/ml) from 260 +/- 39.2% of control growth to 114 +/- 16.4% of control growth (p = 0.02). Inhibition was comparable for IM7.8.1. Control mAb (LM2) to the beta 2 integrin subunit CD11b had no effect on proliferation induced by hyaluronic acid. We demonstrate that hyaluronic acid stimulates the growth of CD34+ selected umbilical cord blood cells into specifically differentiated mature eosinophils. This process is modulated by the CD44 receptor on the progenitor cell population.

Blockade of eosinophil migration by 5-lipoxygenase and cyclooxygenase inhibition in explanted guinea pig trachealis

We studied the effects of 5-lipoxygenase inhibition with A63162 and cyclooxygenase inhibition with indomethacin (INDO) on 1) eosinophil chemotaxis and 2) airway narrowing caused by 10(-6) M formyl-Met-Leu-Phe (fMLP) in tracheal explants from guinea pigs. Airway narrowing was assessed by calibrated micrometry, and eosinophil migration from the lamina propria was expressed as number of eosinophils contained per 1 cm tracheal segment. After 120 min, treatment with fMLP caused an increase in luminal eosinophils from 6,804 +/- 1,786 to 303,347 +/- 75,609 cells (P < 0.001); airway diameter narrowed by 20.4 +/- 1.4%. In six preparations, A63162 inhibited airway narrowing caused by fMLP by 54.9 +/- 6.1%; INDO had a similar effect on airway diameter. However, maximal inhibition of eosinophil migration was greater after 10(-6) M A63162 (38,393 +/- 7,434 cells; P < 0.001 vs. fMLP alone) than after treatment with 10(-5) M INDO (123,547 +/- 19,499 cells; P < 0.05). We demonstrate a method that permits simultaneous measurements of eosinophil migration and airway smooth muscle contraction in a guinea pig tracheal explant preparation. Our data suggest that eosinophil chemotaxis and changes in internal airway diameter are caused by activation of both 5-lipoxygenase and cyclooxygenase pathways and that cell migration is independent of the physical consequences of airway smooth muscle contraction.

Assessment of agonist- and cell-mediated responses in airway microsections by computerized videomicrometry

The objective of this investigation was to develop a method for real-time measurement of changes in luminal area in microexplants of airways during pharmacological and physiological interventions. After guinea pigs were killed, tracheal rings (1- to 2-mm thick) were excised and placed in 300-microliters chambers. The area of the airway lumen was calculated as pixel number with the use of computerized videomicrometry. In 29 epithelium-intact airways, 10(-3) M acetylcholine (ACh) caused decrease in luminal area of 38.1 +/- 2.80% (P < 0.001 vs. 10(-9) M). Spontaneous tone also was demonstrated in 34 preparations from 4 guinea pigs; decrease in area of 17.0 +/- 1.45% after 60-min incubation in buffer alone was blocked completely by 10(-5) M indomethacin (P = 0.01). Luminal narrowing caused by < or = 10(-6) M ACh was reversed completely by 10(-6) M albuterol (P = 0.002). Addition of 100,000 activated human eosinophils caused 24.7 +/- 4.41% decrease in luminal area vs. 7.24 +/- 5.51% for nonactivated cells (P = 0.048). We demonstrate a real-time method for the assessment of auxotonic changes in airway caliber that utilizes microsections of explanted airways and permits the use of extremely small numbers of isolated cells to achieve physiological activation. Concentration-response characteristics and spontaneous tone are similar to those of large chamber preparations, and narrowing is reversed by beta 2-adrenoceptor activation.

Persistent airway hyperresponsiveness and histologic alterations after chronic antigen challenge in cats

We studied the effect of chronic immune sensitization on the airway reactivity and associated cytologic and histologic alterations in initially nonatopic cats, a species that spontaneously develops idiopathic asthma. Seven cats were sensitized by intramuscular injection of Ascaris suum antigen (AA) for 4 wk, and four other cats served as sham controls. Airway sensitization was demonstrated by an increased response to nebulized AA in sensitized animals (RL = 45.9 +/- 6.1 cm H2O/L/s, versus a baseline response of 24.7 +/- 1.5 cm H2O/L/s, p < 0.01), and hyperresponsiveness was demonstrated by an increased response to acetylcholine (ACh)-challenge 24 h after AA (approximately 1.0 log decrease in PD200, p < 0.01). The number of eosinophils in the sensitized animals' bronchoalveolar lavage (BAL) fluid increased 12-fold (p < 0.01 versus control) in response to AA challenge; 32 +/- 5% of the BAL eosinophils had a specific density < 1.050, versus 8 +/- 2% prior to AA challenge (p < 0.05). There was no change in airway reactivity, eosinophil recovery, or density in the control group 24 h after sham challenge with saline. The same seven sensitized cats further received nebulized AA three times weekly for 4 to 6 wk, after which BAL samples were again obtained and ACh dose-response curves generated 72 h after the final administration of nebulized AA. Airway hyperresponsiveness increased (approximately 1.5 log decrease in PD200, p < 0.001) and the number of eosinophils recovered in BAL fluid was increased 11-fold (p < 0.05). Necropsy specimens demonstrated bronchoconstriction in AA-challenged animals but not controls; luminal narrowing was accompanied by: (1) a 29.0 +/- 0.34% increase in smooth-muscle thickness (p < 0.05); (2) goblet-cell and submucosal-gland hypertrophy and hyperplasia; and (3) epithelial erosion and eosinophilic infiltration. We demonstrate in nonhuman species persistent airway hyperreactivity associated with a complete constellation of histologic changes in epithelium, smooth muscle, and mucus glands, and cytologic changes in BAL fluid, all induced by immune sensitization. Our data suggest that chronic immune sensitization per se could be a salient factor in causing many of the changes associated with chronic bronchial asthma.

Cyproheptadine-induced attenuation of type-I immediate-hypersensitivity reactions of airway smooth muscle from immune-sensitized cats

We assessed the effect of serotonergic inhibition by cyproheptadine on the responsiveness of tracheal smooth muscle (TSM) strips and epithelium-intact third-generation bronchial rings from immune-sensitized (Ascaris suum) cats after exposure to antigen. Cats were sensitized by IM administration of antigen and adjuvant twice over a 4-week period. Sensitization was confirmed in vivo by skin testing with antigen and by physiologic airway responses after exposure to nebulized antigen. Tissues were tethered isometrically to force transducers and were actively equilibrated by exposures to KCl-substituted perfusate. Maximal response after exposure to antigen (expressed as percentage of maximal contraction of each tissue to 63 mM KCl (%KCl) was 169 +/- 18% KCl for sensitized TSM and 43 +/- 18% KCl for sensitized TSM pretreated with cyproheptadine (P < 0.001). Similarly, maximal response to antigen was 81 +/- 27% KCl for sensitized bronchial rings, compared with 16 +/- 14% KCl for sensitized bronchial rings pretreated with cyproheptadine (P = 0.05 vs control). Blockade of leukotriene synthesis by 10(-6) to 10(-4) M A-64077, a selective 5-lipoxygenase inhibitor, had no significant effect on peak response for either TSM (193 +/- 13% KCl vs 169 +/- 18% KCl for sensitized untreated TSM) or bronchial rings (79 +/- 20% KCl vs 81 +/- 27% KCl for sensitized untreated bronchial rings). Release of serotonin from airway tissues was confirmed by the presence of serotonin in the perfusate of 8 sensitized TSM preparations after, but not before, antigen challenge.(ABSTRACT TRUNCATED AT 250 WORDS)

Contraction of human bronchial smooth muscle caused by activated human eosinophils

We assessed the effect of activated eosinophils isolated from human peripheral blood in causing contraction of explanted human bronchi in vitro. Sixty-three epithelium-intact fifth generation airway sections were obtained from 16 subjects undergoing lung resection for carcinoma. Eosinophils were isolated by negative immunoselection, and activation with 10(-7) M platelet-activating factor (PAF) was confirmed by measurements of eosinophil peroxidase (EPO) secretion and superoxide (O2-.) generation. EPO secretion increased from 68.6 +/- 13.4 ng/10(6) cells to 420 +/- 125 ng/10(6) cells after activation with PAF (P < 0.05). Similarly, PAF-induced O2-. generation increased from 15.3 +/- 4.64 nmol cytochrome c reduced/10(5) cells to 44.2 +/- 8.50 nmol cytochrome c reduced/10(5) cells (P < 0.05). Cells were instilled into an isolated airway pouch preparation, and, 60 min later, airway contractile responses were determined by optical micrometry as percent decrease in lumenal diameter (%decrease) and percent increase in wall thickness (%increase) using a calibrated magnifying lens. Treatment with either vehicle, PAF alone, or untreated eosinophils had no effect on airway caliber or thickness. PAF-activated cells caused a 30.5 +/- 1.52% decrease in airway caliber (P < 0.001 vs. untreated cells) and a 36.6 +/- 2.54% increase in wall thickness (P < 0.001 vs. untreated cells). Preincubation with A63162, a 5-lipoxygenase inhibitor, caused concentration-dependent inhibition of airway narrowing. After 10(-5) M A63162, decrease in airway diameter caused by PAF was 8.00 +/- 0.10% vs. 30.5 +/- 1.52% for PAF alone (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Migration of human and guinea pig airway epithelial cells in response to calcitonin gene-related peptide

Calcitonin gene-related peptide (CGRP) is contained within and secreted by nerves and neuroepithelial bodies in the airway epithelium. To determine whether CGRP is a chemoattractant, tracheal epithelial cells isolated from 23 guinea pigs, and bronchial epithelial cells isolated from seven human donors were grown in primary culture for 4 to 5 days. Cell migration was assessed in a blindwell chemotaxis chamber. A gelatin-coated polycarbonate filter (8-microns pore size) separated the upper wells containing 5 x 10(4) cells from the lower wells containing chemoattractant (either CGRP or insulin). Cells were stimulated for 6 h, after which migrated cells on the filter were stained and counted. Both insulin and CGRP elicited migration of guinea pig tracheal epithelial (GPTE) cells. Exposure to 30 micrograms/ml insulin caused migration of 26.5 +/- 4.0 cells versus 4.3 +/- 0.6 cells per 10 hpf for control (P < 0.001). Treatment with 10(-9) M CGRP elicited migration of 39.6 +/- 2.5 cells versus 2.6 +/- 0.9 cells per 10 hpf for control (P < 0.001). Human bronchial epithelial (HBE) cells also migrated after stimulation with either insulin or CGRP: after 10(-9) M CGRP, HBE cell migration was 41.0 +/- 6.1 cells versus 3.4 +/- 0.3 cells per 10 hpf (P < 0.002; n = 3). Checkerboard analysis showed that the migration to CGRP was both chemotactic and chemokinetic. Incubation with 10(-8) M hCGRP-(8-37), a receptor antagonist for CGRP, plus 10(-9) M CGRP decreased GPTE cell migration to 9.8 +/- 2.4 cells versus 38.6 +/- 1.2 cells per 10 hpf for 10(-9) M CGRP alone (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Passive sensitization of human bronchi augments smooth muscle shortening velocity and capacity

We assessed whether incubation with human serum from atopic individuals containing high concentrations of immunoglobulin E (IgE) causes augmentation of maximal contraction of human bronchial smooth muscle from non-atopic subjects in vitro. Bronchi were obtained from eight patients undergoing lung resection, and force-velocity relationships were determined for eight pairs of epithelium-intact bronchial rings of generations 6-7 using an electromagnetic lever system, which allowed isotonic shortening when load-clamps [from 0 to maximal isometric force (P0)] were applied at specific times after onset of contraction. Contractions were elicited by supramaximal electrical field stimulation (50 Hz, 10 s train duration, 25 V). Optimal length (Lo) for each tissue was determined during equilibration. After resection, tissues were sensitized passively with human sera containing high titers (> 1,000 U/ml) of IgE by incubation for 16 h at 20 degrees C. Maximal shortening velocity (Vmax) was increased for passively sensitized bronchi [0.1150 +/- 0.0240 1/2 circumferences/s (1/2Cir/s)] compared with sham-sensitized bronchi [0.0731 +/- 0.0152 1/2Cir/s, P = 0.038]. Similarly, maximal shortening (delta Lmax) was augmented in sensitized bronchial rings (11.27 +/- 1.80 %Lo) compared with sham-sensitized tissues (8.19 +/- 1.39 %Lo, P = 0.012). However, P0 did not differ between sensitized (122.5 +/- 24.4 mN/cm2) compared with sham-sensitized tissues (138.4 +/- 32.1 mN/cm2, P = 0.642). Our data are the first demonstration that Vmax and delta Lmax are augmented in sensitized but not challenged human bronchial rings after passive sensitization using human serum containing high concentrations of IgE.

Augmentation of stimulated eosinophil degranulation by VLA-4 (CD49d)-mediated adhesion to fibronectin

We examined the effect of VLA-4-mediated adhesion to purified fibronectin (FN) on the stimulated release of the granular protein, eosinophil peroxidase (EPO), in human peripheral blood eosinophils. In initial studies, optimal time-course and concentration-effect relationships were determined; eosinophil adhesion to FN-coated styrene plates was maximal in wells coated with 10 micrograms/ml FN after incubation in the wells for 60 min (17,097 +/- 3,670 adherent eosinophils/well versus 6,789 +/- 925 adherent eosinophils/well in control wells; P < 0.005). Treatment of eosinophils with 10(-8) to 10(-6) M formylmethionylleucyl-phenylalanine (FMLP) + 5 micrograms/ml cytochalasin B (CYTB) caused a concentration-dependent increase in EPO release, which was augmented by preincubation of eosinophils for 120 min in FN-coated (10 micrograms/ml) styrene wells versus eosinophils preincubated in control wells. At 10(-6) M FMLP+CYTB, initial adhesion to FN for 120 min caused an increase in the secretion of EPO from 367 +/- 26 to 485 +/- 25 ng/10(6) eosinophils (P = 0.0001). Treatment of eosinophils during incubation in FN-coated wells with the anti-VLA-4 monoclonal antibody HP2/1 attenuated stimulated EPO secretion caused by 10(-6) M FMLP+CYTB from 497 +/- 40 to 285 +/- 26 ng/10(6) eosinophils (P < 0.02). Similarly, treatment with HP2/1 caused a decrease in eosinophil adhesion to FN-coated styrene from 12,693 +/- 1,866 to 6,206 +/- 852 adherent cells/FN-coated well (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Immune sensitization augments epithelium-dependent spontaneous tone in guinea pig trachealis

We examined epithelial modulation of tracheal smooth muscle (TSM) responsiveness in vitro from guinea pigs receiving active immune sensitization in vivo. Initially, guinea pigs were either ovalbumin sensitized (by aerosol) or sham sensitized with normal saline; TSM responsiveness was assessed isometrically as active tension (AT) after equilibration by electrical field stimulation in vitro. For epithelium-intact (Epi+) tissues, sensitization caused an increase in baseline active spontaneous tone (1.89 +/- 0.20 g AT) vs. sham-sensitized tissues (1.18 +/- 0.28 g AT; P = 0.02). Spontaneous tone in sensitized TSM in which the epithelium was removed (Epi-) (1.01 +/- 0.14 g AT) was substantially less than from Epi+ tissues (P = 0.01) and did not differ from sham-sensitized epithelium-denuded tissues (0.82 +/- 0.24 g AT; P > 0.05). Indomethacin caused a reduction in spontaneous tone to comparable magnitude for all treatment paradigms. Immune sensitization caused physiological reduction in the ability to relax in response to isoproterenol; the concentration of isoproterenol eliciting 50% relaxation of spontaneous tone was 7.10 +/- 0.13 (-log M) for TSM from sensitized guinea pigs compared with 8.20 +/- 0.27 (-log M) for sham-sensitized tissues (P = 0.006). However, after precontraction with exogenous acetylcholine, relaxation caused by isoproterenol was not affected by either indomethacin or epithelial removal. Muscarinic responsiveness to acetylcholine was augmented by immune sensitization; however, the increase in response to acetylcholine was attenuated by epithelium removal or cyclooxygenase blockade.(ABSTRACT TRUNCATED AT 250 WORDS)

Ontogeny of dry gas hyperpnea-induced bronchoconstriction in guinea pigs

Adolescent guinea pigs (AGPs) demonstrate dry gas hyperpnea-induced bronchoconstriction (HIB) that shares key features with HIB in humans with asthma. The airways of immature animals exhibit enhanced reactivity to diverse types of stimulation. We tested whether dry gas HIB is also increased in newborn guinea pigs (NGPs). We quantified HIB as the fractional increase of respiratory system resistance (Rrs) over baseline (BL) in five 4- to 7-day-old NGPs after 10 min of hyperpnea, as well as changes in Rrs elicited by intravenous methacholine or capsaicin, and compared these responses with those of AGPs. During hyperpnea, analogous stimuli were delivered by mechanically imposing hyperpnea at 3.0, 4.5, and 6.0 times quiet eucapnic minute ventilation (VE). In AGPs, hyperpnea caused significant bronchoconstriction that increased with VE; peak fractional increase of Rrs was 7.6 +/- 2.0 times BL. In contrast, hyperpnea caused insignificant bronchoconstriction in NGPs (1.4 +/- 0.2 times BL after the largest VE; P < 0.05 vs. AGP). Responses elicited by methacholine (10(-10)-10(-7) mol/kg) or capsaicin (0.01-10.0 microgram/kg) were similar in NGPs and AGPs. In AGPs, hyperpnea suppressed HIB until posthyperpnea. To determine whether the reduced HIB of NGPs was caused by enhanced suppression, NGPs and AGPs were administered acetylcholine (10(-10)-10(-7) mol/kg i.v.) during BL eucapnic ventilation and during eucapnic hyperpnea with warm humidified gas. Responses to acetylcholine were suppressed in AGPs and NGPs to a similar degree. We conclude that HIB is markedly diminished shortly after birth in guinea pigs and that it increases substantially during maturation.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta adrenergic modulation of formyl-methionine-leucine-phenylalanine-stimulated secretion of eosinophil peroxidase and leukotriene C4

The inhibitory effect of beta-2 adrenergic receptor stimulation on leukotriene C4 (LTC4) secretion and eosinophil peroxidase (EPO) release caused by exogenous activation with 10(-8) to 10(-6) M formyl-met-leu-phe (fMLP) + 5 micrograms/ml of cytochalasin B (Cyto B) in purified human peripheral blood eosinophils was studied. Cells from normal subjects were isolated by negative immunoselection and remained > or = 98% viable as determined by trypan blue exclusion. Duplicate aliquots of eosinophils (10(5) cells/intervention) were activated with 1) fMLP + Cyto B alone, 2) fMLP + Cyto B after pretreatment with 10(-8) M albuterol, 3) 10(-8) M albuterol + fMLP + Cyto B after pretreatment with 10(-8) M propranolol or 4) vehicle control. After incubation, the supernatants were tested for concentration of LTC4 and EPO. Concentration-related release of EPO was demonstrated for 10(-8) M fMLP + 5 micrograms/ml of Cyto B to 10(-6) M fMLP + 5 micrograms/ml of Cyto B, and the greatest concentration of fMLP was used in all subsequent studies. FMLP + Cyto B caused substantial LTC4 secretion in eosinophils (300 +/- 83.0 pg/ml) as compared to sham-activated eosinophils (3.3 +/- 1.9 pg/ml; P < .02). Similarly, maximum EPO release increased from 277 +/- 17.8 to 3956 +/- 1230 ng/10(6) cells (P < .02) after activation with fMLP + Cyto B. Treatment with albuterol decreased markedly both LTC4 secretion to 144 +/- 54.0 pg/ml (P < .05 vs. fMLP + Cyto B-activated eosinophils) and EPO release to 1993 +/- 368 ng/10(6) cells (P < .05 vs. fMLP + Cyto B-activated eosinophils).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of airway inflammation on smooth muscle shortening and contractility in guinea pig trachealis

We studied the effect of either 1) immunogenic inflammation caused by aerosolized ovalbumin or 2) neurogenic inflammation caused by aerosolized capsaicin in vivo on guinea pig tracheal smooth muscle (TSM) contractility in vitro. Force-velocity relationships were determined for nine epithelium-intact TSM strips from ovalbumin-sensitized (OAS) vs. seven sham-sensitized controls and TSM strips for seven animals treated with capsaicin aerosol (Cap-Aer) vs. eight sham controls. Muscle strips were tethered to an electromagnetic lever system, which allowed isotonic shortening when load clamps [from 0 to maximal isometric force (Po)] were applied at specific times after onset of contraction. Contractions were elicited by supramaximal electrical field stimulation (60 Hz, 10-s duration, 18 V). Optimal length for each muscle was determined during equilibration. Maximal shortening velocity (Vmax) was increased in TSM from OAS (1.72 +/- 0.46 mm/s) compared with sham-sensitized animals (0.90 +/- 0.15 mm/s, P < 0.05); Vmax for TSM from Cap-Aer (0.88 +/- 0.11 mm/s) was not different from control TSM (1.13 +/- 0.08 mm/s, P = NS). Similarly, maximal shortening (delta max) was augmented in TSM from OAS (1.01 +/- 0.15 mm) compared with sham-sensitized animals (0.72 +/- 0.14 mm, P < 0.05); delta max for TSM from Cap-Aer animals (0.65 +/- 0.11 mm) was not different from saline aerosol controls (0.71 +/- 0.15 mm, P = NS). We demonstrate Vmax and delta max are augmented in TSM after ovalbumin sensitization; in contrast, neurogenic inflammation caused by capsaicin has no effect on isolated TSM contractility in vitro. These data suggest that airway hyperresponsiveness in vivo that occurs in association with immunogenic or neurogenic inflammation may result from different effects of these types of inflammation on airway smooth muscle.

Tuberculosis control policies in major metropolitan health departments in the United States. V. Standard of practice in 1992

Since 1978, we have surveyed the 28 metropolitan health departments initially reporting > 250 cases of tuberculosis/yr to determine the standard of practice in the control of pulmonary tuberculosis and the factors affecting treatment policy. In this survey, results were compared with data obtained in 1978, 1980, 1984, and 1988. As in the previous years, all departments completed the survey. The predominant treatment regimen was 6 months of chemotherapy (64 +/- 1.33% of patients) involving isoniazid (I), rifampin (R), and pyrazinamide (Z). Estimated duration of treatment, which had decreased from 20.2 +/- 2.1 months in 1980 to 7.58 +/- 1.02 months in 1988, increased to 9.34 +/- 2.32 months in 1992 (p < 0.01). This was attributed to an increase in drug-resistant cases (17 of 25 programs) and to increased incidence of HIV infection during the previous 4 yr. In 1984, HIV infection was estimated to coincide with tuberculosis in 2.54% of all patients, 7.72% in 1988, and 17.42% in 1992. Several other major departures from prior perceived practices were reported. In 1980, 32.1% of all patients were hospitalized initially for tuberculosis treatment, and this number decreased progressively to 17.8% in 1988; in 1992, 34.2 +/- 1.32% of patients with tuberculosis were hospitalized for initial treatment. In 1988, no program reported regular use of alternative therapy to isoniazid for chemoprophylaxis; in 1992, 21 programs used alternative regimens (predominantly R-containing). In 1992, nine programs reported increased funds for treatment of tuberculosis (27.2 +/- 1.97% after inflation), whereas 16 reported a mean decrease of 14% after inflation.(ABSTRACT TRUNCATED AT 250 WORDS)