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Animal Models |
From the Department of Pathology *
and the Division of
Pulmonary and Critical Care,
Department of
Internal Medicine, University of Michigan Medical School, Ann
Arbor, Michigan
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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(IFN-) and transforming growth factor (TGF-ß)
levels were present in whole lung homogenates up to 7 days after the
conidia challenge. At day 30 after conidia challenge,
significantly elevated levels of interleukin-4 (IL-4) and IL-13 were
present in the A. fumigatus-sensitized mice.
Histological analysis revealed profound goblet cell hyperplasia and
airway fibrosis at days 30 after conidia, and the latter
finding was confirmed by hydroxyproline measurements. Thus the
introduction of A. fumigatus conidia into A.
fumigatus-sensitized mice results in persistent airway
hyperresponsiveness, fibrosis, and goblet cell
hyperplasia.
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Although it is widely recognized that more research is required to identify therapeutic strategies that prevent airway remodeling during allergic airway disease, simple reproducible animal models that recapitulate chronic changes in the airways are lacking. Several models of allergen-specific airway eosinophilia and altered airway physiology have previously been described.12-14 Unfortunately, the majority of existing models lack persistent airway hyperresponsiveness, mucus cell hyperplasia, and peribronchial fibrotic changes typical of long-term clinical disease. In the present study, we describe a murine model of Aspergillus fumigatus allergen-induced airway disease that exhibits airway hyperresponsiveness, goblet cell hyperplasia, and airway fibrosis. A. fumigatus was the allergen of choice in this chronic model of allergic airway disease. Clinical hypersensitivity responses to A. fumigatus, commonly referred to as allergic bronchopulmonary aspergillosis (ABPA), can be characterized by asthma-like responses, bronchiectasis, eosinophilia, mucus hypersecretion, and pulmonary fibrosis.15,16 A detailed description of the airway structural changes and the lung cytokine profile associated with this chronic model of allergic airway disease are provided in the present study. Finally, the development of a chronic model allows for the further evaluation of inflammatory mediators that are involved in the chronic stage of allergic airway disease and for the testing of specific therapeutics.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Specific-pathogen free (SPF) female CBA/J mice (Jackson Laboratories, Bar Harbor, ME) were maintained in a SPF facility for the duration of this study. Prior approval for mouse usage in the development of the ABPA model described herein was obtained from the University Laboratory Animal Medicine facility at the University of Michigan Medical School. Sensitization of mice to a commercially available preparation of soluble A. fumigatus antigens was performed as previously described in detail.17 Briefly, mice received an intraperitoneal and subcutaneous injection of soluble A. fumigatus antigens dissolved in incomplete Freund’s adjuvant. Two weeks after systemic sensitization, each mouse then received a weekly intranasal challenge with A. fumigatus antigen to localize the allergic responsiveness to the airways. One week after the third intranasal challenge, each mouse then received 5.0 x 106 A. fumigatus conidia suspended in 30 µl of 0.1% Tween-80 via the intratracheal route. Nonsensitized mice received normal saline alone via the same routes and over the same time periods, and received the same number of conidia. Sensitized and non-sensitized mice were anesthetized with Vetamine (ketamine hydrochloride, 100 mg/kg i.p.; Mallinckrodt Veterinary, Mundelein, IL) before the intratracheal challenge with conidia. This dose of A. fumigatus conidia has previously been shown to be nonlethal in normal mice.18 A. fumigatus strain 13073 was cultured as described elsewhere.19 Conidia obtained from these cultures were suspended in a solution containing 0.1% Tween-80 solution and quantified by particle counter (Z2 particle analyzer; Coulter, Hialeah, FL.).
Determination of Systemic IgE
Sera from A. fumigatus-sensitized and nonsensitized mice were analyzed for total IgE at various times before and after conidia challenge. Complementary capture and detection antibody pairs for mouse IgE were purchased from PharMingen (San Diego, CA), and the IgE enzyme-linked immunosorbent assay (ELISA) was performed according to the manufacturer’s directions. Duplicate sera samples were diluted to 1:100, IgE levels in each were calculated from optical density readings at 492 nm, and IgE concentrations were calculated from a standard curve generated using recombinant IgE (5–2000 pg/ml).
Measurement of Bronchial Hyperresponsiveness
Immediately before and at days 3, 7, and 30 after the
intratracheal A. fumigatus conidia challenge, bronchial
hyperresponsiveness in A. fumigatus-sensitized and
nonsensitized mice was assessed in a Buxco plethysmograph (Buxco, Troy,
NY).20
Sodium pentobarbital (40 mg/kg i.p.; Butler Co.,
Columbus, OH) was used to anesthetize mice before their intubation for
ventilation with a Harvard pump ventilator (Harvard Apparatus, Reno,
NV). The following ventilation parameters were used: tidal volume
= 0.25 ml, breathing frequency = 120/minutes, and positive
end-expiratory pressure 
3 cm H2O. Within the
sealed plethysmograph mouse chamber, transpulmonary pressure (ie, 
tracheal pressure - mouse chamber pressure) and inspiratory volume
or flow were continuously monitored online by an adjacent computer.
Airway resistance was calculated online via computer software (Buxco)
and was determined by the division of the transpulmonary pressure by
the change in inspiratory volume. After a baseline period in the Buxco
apparatus, anesthetized and intubated mice received a dose of 10 µg
of methacholine by tail vein injection, and airway responsiveness to
this nonselective bronchoconstrictor was again calculated online.
Because nonsensitized mice typically exhibited a little change in
airway resistance after a 10-µg methacholine challenge, this dose of
methacholine was subsequently used to reveal changes in airway
hyperresponsiveness in both conidia models. At the conclusion of the
assessment of airway responsiveness each mouse was killed by
exsanguination, and a bronchoalveolar lavage (BAL) was performed with 1
ml of normal saline. Approximately 500 µl of blood was also collected
from each mouse and transferred to a microcentrifuge tube. Sera were
obtained after the sample was centrifuged at 15,000 rpm for 10 minutes.
Whole lungs were finally dissected from each mouse and snap frozen in
liquid N2 or prepared for histological analysis.
Morphometric Analysis of Leukocyte Accumulation in BAL Samples
Neutrophils, macrophages, eosinophils, and lymphocytes were quantified in BAL samples applied to coded microscope slides with a cytospin (Shandon Scientific, Runcorn, UK). Identification of each cell type in the cytospins was facilitated by Wright-Giemsa differential stain, and the average number of each cell type was determined in 15 high-powered fields (HPF) (x1000) on every slide.
Cytokine ELISA Analysis
Murine interleukin-18 (IL-18), interferon- (IFN-), IL-10,
transforming growth factor-ß (TGF-ß), IL-4, IL-5, and IL-13 protein
levels were determined in 50 µl of whole lung homogenates, using a
standardized sandwich ELISA technique previously described in
detail.21
Whole lungs were homogenized in 2 ml of normal
saline containing 2 mg of protease inhibitor (Complete; Boehringer
Mannheim, Indianapolis, IN) with a Tissue Tearor. Nunc-immuno ELISA
plates (MaxiSorp) were coated with the appropriate capture antibody
(R&D Systems, Minneapolis, MN) at a dilution of 1–5 µg/ml of coating
buffer (in mol/L: 0.6 NaCl; 0.26
H3BO4; 0.08 NaOH; pH 9.6)
overnight at 4°C. The unbound capture antibody was washed away and
each plate was blocked with 2% bovine serum
albumin—phosphate-buffered saline (BSA-PBS) for 90 minutes at 37°C.
Each ELISA plate was then washed with PBS tween 20 (0.05%; v/v), and
50 µl of undiluted or diluted 1:10 whole lung homogenate was added to
duplicate wells and incubated for 1 hour at 37°C. After the
incubation period, the ELISA plates were then thoroughly washed and the
appropriate biotinylated polyclonal rabbit antibody (3.5 µg/ml) was
added. After the plates were washed 30 minutes later,
streptavidin-peroxidase (Bio-Rad Laboratories, Richmond, CA) was added
to each well for 30 minutes, and then they were thoroughly washed
again. Chromagen substrate (Bio-Rad Laboratories) was added and optical
readings at 492 nm were obtained with an ELISA plate scanner.
Recombinant murine cytokines were used to generate the standard curves
from which the concentrations present in the samples were derived. The
limit of ELISA detection for each cytokine was consistently above 50
pg/ml. Each ELISA was screened to ensure the specificity of each
antibody used.
Whole Lung Histological Analysis
Whole lungs from nonsensitized and A. fumigatus-sensitized mice before and after A. fumigatus conidia challenge were fully inflated by the intratracheal perfusion with 4% paraformaldehyde. Lungs were then dissected and placed in fresh paraformaldehyde for 24 hours. Routine histological techniques were used to paraffin-embed this tissue, and 5-µm sections of whole lung were stained with hematoxylin and eosin, Masson trichrome, periodic acid Schiff (PAS), and Gomori methanamine silver (GMS). Inflammatory infiltrates and other histological changes were examined around bronchioles and larger airways, using light microscopy because the eosinophilic inflammation was exclusively associated with these pulmonary structures. Eosinophils were counted at high magnification (x1000), using a multiple-step analysis of whole lung histological sections mounted on coded slides. A minimum of 20 airways was analyzed on each slide, and data were expressed as the average number of airway-associated eosinophils per HPF.
Hydroxyproline Assay
Total lung collagen levels were determined using a previously described assay.22 Briefly, a 500-µl sample of lung homogenate (see above) was subsequently added to 1 ml of 6 N HCl for 8 hours at 120°C. To a 5-µl sample of the digested lung, 5 µl of citrate/acetate buffer (5% citric acid, 7.2% sodium acetate, 3.4% sodium hydroxide, and 1.2% glacial acetic acid, pH 6.0) and 100 µl of chloramine-T solution (282 mg chloramine-T, 2 ml of n-propanol, 2 ml of distilled water, and 16 ml of citrate/acetate buffer) were added. The resulting samples was then incubated at room temperature for 20 minutes before 100 µl of Ehrlich’s solution (Aldrich, Milwaukee, WI), was added. These samples were incubated for 15 minutes at 65°C, and cooled samples were read at 550 nm in a Beckman DU 640 spectrophotometer. Hydroxyproline concentrations were calculated from a standard curve of hydroxyproline (zero to 100 µg/ml).
Data Statistical Analysis
All results are expressed as mean ± SEM (SE). Analysis of variance (ANOVA) and Dunnett’s test for multiple comparisons were used to determine statistical significance in both groups at various times after the conidia challenge; P < 0.05 was considered statistically significant.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Invasive aspergillosis is commonly observed in immunodeficient patients,23 and this disease can be reproduced in mice rendered neutropenic with cyclophosphamide treatment and then challenged intratracheally with A. fumigatus conidia.19 In the present study, GMS-stained histological sections of whole lung from nonsensitized and A. fumigatus-sensitized mice did not show any evidence of hyphae or invasive growth at any time after conidia challenge. In addition, A. fumigatus could not be cultured from BAL samples removed from either group at 3, 7, and 30 days after conidia challenge (not shown). These findings suggested that allergic airway disease induced in nonsensitized and A. fumigatus-sensitized mice was not associated with fungal colonization or invasive disease after conidia challenge.
Profoundly Increased Serum IgE in A. fumigatus-Sensitized Mice Challenged Intratracheally with Conidia
Increased IgE is a hallmark of hypersensitivity to A.
fumigatus,23,24
and IgE levels fluctuate with ABPA
severity.25,26
Measurement of serum IgE levels in the
present study revealed a marked difference in the generation of IgE by
the two groups after their challenge with A. fumigatus
conidia (Figure 1)
. As expected, mice
previously sensitized to A. fumigatus had approximately
5250 ± 500 ng/ml of IgE immediately before conidia challenge,
whereas total IgE levels were below the level of detection in the
nonsensitized group. In both groups, peak IgE levels were measured at
day 7 after conidia, but approximately fivefold greater levels of IgE
were evident in the A. fumigatus-sensitized mice compared
with the nonsensitized group (Figure 1)
. In both groups, the levels of
total IgE remained significantly elevated above baseline levels at day
30 after conidia. Thus these results suggested that the introduction of
A. fumigatus conidia into sensitized mice greatly augmented
the IgE response to this fungus.
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We have previously examined airway hyperresponsiveness in mice
that were sensitized with soluble A. fumigatus antigens and
observed that airway physiology had returned to normal by day 3 after
an intratracheal challenge with soluble A.
fumigatus.17
In the present study, our objective was
to obtain a model in which airway physiology changes persisted for a
much longer time. Accordingly, airway physiology was monitored
immediately before and at various days after the intratracheal
challenge of nonsensitized and A. fumigatus-sensitized mice
with A. fumigatus conidia. Before conidia, the two groups of
mice exhibited similar changes in airway resistance (units = cm
H2O/ml/second) after intravenous
methacholine provocation (Figure 2)
.
However, neither group showed airway responses at this time that were
significantly increased above the baseline airway resistance measured
in the absence of methacholine (Figure 2
; the dashed line is the
baseline response for both groups of mice). At day 3 after conidia,
airway hyperresponsiveness was significantly increased threefold above
the baseline in the nonsensitized group, whereas airway resistance was
increased fourfold above the baseline in the A.
fumigatus-sensitized group. At days 7 and 30 after conidia,
significantly increased airway responsiveness to methacholine was
present only in mice previously sensitized to A. fumigatus
(Figure 2)
. Thus these results demonstrated that persistent airway
hyperresponsiveness is a consequence of conidia challenge in mice
previously sensitized to A. fumigatus and that chronic
changes to airway physiology can occur in a murine model of allergic
airway disease.
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We next examined leukocyte populations within BAL samples before
and after conidia challenge, and major differences in eosinophil and
lymphocyte numbers were apparent between the two groups of mice
described here. BAL samples from mice previously sensitized to A.
fumigatus contained 25 ± 5 and 25 ± 2 eosinophils per
high-powered field (HPF) at days 3 and 7, respectively, after conidia
challenge (Figure 3A)
. At day 30 after
conidia, eosinophils (4 ± 2 per HPF) were still present in BAL
samples from the sensitized group. The greatest number of lymphocytes
was detected at day 7 after conidia challenge (10 ± 3 per HPF),
and lymphocyte counts remained significantly elevated at day 30 after
conidia challenge (9 ± 3 per HPF) (Figure 3B)
. In contrast, minor
increases in eosinophil and lymphocyte numbers were observed in BAL
samples from nonsensitized mice that received conidia alone (Figures 3, A and B
, respectively). Overall, the changes in neutrophils and
macrophage counts in the BAL were similar in the two conidia groups
(Figures 3, C and D
, respectively). Neutrophil and macrophage counts in
the BAL were significantly elevated at days 3 and 7, respectively,
after conidia in both groups of mice (Figure 3)
. Thus these data
suggested that the pulmonary inflammatory response to conidia differed
greatly between the two groups of mice. This difference was most aptly
illustrated by the markedly increased movement of eosinophils and
lymphocytes into the BAL compartment during the conidia challenge.
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The intratracheal introduction of soluble A. fumigatus
antigens into mice increases the synthesis of Th2- and Th1-type
cytokines within the lung.27
More recently, Grunig and
colleagues28
have shown that IL-10 is a natural modulator
of inflammatory Th2-type as well as Th1-type responses during
experimental ABPA. Figure 4,A and B
,
illustrates the changes in two common examples of Th1-type cytokines,
namely IL-18 and IFN-, measured before (ie, baseline levels) and
after conidia challenge in nonsensitized and A.
fumigatus-sensitized mice. Baseline IL-18 levels in whole lung
samples were significantly higher in the sensitized group compared with
the nonsensitized group (Figure 4A)
. After the conidia challenge, the
two groups of mice showed similar significant elevations in IL-18.
Furthermore, IL-18 remained significantly elevated above baseline
levels in the nonsensitized group at day 30 after conidia. IFN-
levels were similar in the two groups before the conidia challenge, but
whole lung samples from the sensitized group contained significantly
greater IFN- at day 3 after conidia challenge compared with the
baseline levels (Figure 4B)
. At the later time points, IFN- levels
in both groups were not different from baseline levels. Also depicted
in Figure 4
are changes in the Th2-type cytokine IL-4 (panel C).
Baseline levels of IL-4 cytokines in whole lung homogenates were
elevated in the sensitized group compared with the nonsensitized group.
Whole lung levels of IL-4 were similar in the two groups at days 3 and
7 after conidia. However, IL-4 levels were significantly greater in the
sensitized group compared with the nonsensitized group at day 30 after
conidia.
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depicts whole lung levels of
IL-10, TGF-ß, and IL-13 before and after conidia challenge. Whole
lung IL-10 levels were similar in the two groups before conidia and
both showed similar significant decreases in IL-10 at day 3 after
conidia (Figure 5A)
. At day 30, IL-10 levels in both groups were
similar to baseline levels. In contrast, TGF-ß and IL-13 showed
divergent patterns of expression in the two conidia groups both before
and after conidia challenge. Before conidia challenge, TGF-ß levels
were increased significantly by fourfold in the nonsensitized group
compared with the sensitized group. At day 3 after conidia, the levels
of TGF-ß were significantly increased eightfold in the A.
fumigatus-sensitized group but decreased by fourfold in the
nonsensitized group (Figure 5B)
. The two conidia groups had similar
levels of TGF-ß at day 30 after conidia. IL-13 levels in lung
homogenates were similar in the two groups before conidia. At day 3
after conidia, IL-13 levels in the nonsensitized group were
significantly increased twofold above baseline levels. In contrast,
significantly more IL-13 was detected only at day 30 after conidia
challenge in the A. fumigatus-sensitized group. Thus major
differences in the magnitude and timing of cytokine production were
detected in whole lung homogenates from nonsensitized and A.
fumigatus-sensitized mice after conidia challenge.
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Many of the characteristic histological features of chronic human
asthma were present in whole lungs from A.
fumigatus-sensitized mice, particularly at the latter times of the
conidia challenge period. Conversely, the nonsensitized group
challenged with conidia exhibited fewer of these features, and at day
30 whole lungs from this group lacked all of the chronic features of
chronic airway disease. As shown in Figure 6
, although absent from normal mice (A),
an eosinophilic infiltrate was present around the airways of A.
fumigatus-sensitized mice before the conidia challenge (Figure 6B)
. Eosinophils and lymphocytes were commonly juxtaposed with small
and large airways in both groups of mice at day 7 after conidia (Figure 6C)
. However, the eosinophilic and lymphocytic inflammation was of much
greater intensity in the sensitized mice at this time. As shown in
Figure 6D
, sensitized mice showed profound airway and parenchymal
inflammation at day 7 after conidia. At day 30 after conidia, airway
inflammation was not observed in the nonsensitized group (Figure 6E)
,
but evidence of some airway inflammation was still apparent in
sensitized mice at this time (Figure 6F)
.
|
. Whole lungs from A.
fumigatus-sensitized mice stained with PAS showed airway
epithelial cell hypertrophy, mucus cell metaplasia, and the
hyperproduction of acidic mucus in large and small airways at all times
after conidia challenge (Figure 7, D, F, and H)
. Similar increases in
mucus cell numbers and hyperproduction of acidic mucus were absent from
nonsensitized mice challenged with conidia.
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. Collagen staining was similar in the
two groups before the conidia challenge (Figure 8, A and B)
. At day 30
after conidia, collagen staining did not appear to be markedly
increased above baseline in the nonsensitized group. Nevertheless, at
the same time after conidia, the Masson trichrome staining revealed a
marked increase in collagen surrounding the airways of the A.
fumigatus-sensitized group. Thus the intratracheal introduction of
conidia into A. fumigatus-sensitized mice markedly altered
the pulmonary architecture.
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The changes in Masson trichrome staining described above suggested
that the airways of A. fumigatus-sensitized mice were
surrounded with markedly greater amounts of collagen at day 30 after
conidia. To confirm these histological findings, total hydroxyproline
was measured in whole lung samples removed from both groups before and
at 30 days after conidia challenge. Approximately 2 µg/ml of
hydroxyproline was present in whole lung samples from both groups
before conidia challenge. At day 30 after conidia, both groups showed
significantly greater levels of hydroxyproline compared with their
respective baseline levels before conidia challenge (Figure 9)
. However, hydroxyproline levels were
significantly greater in the sensitized group compared with the
nonsensitized group at this time. Thus these findings confirm that the
introduction of conidia into A. fumigatus-sensitized mice
was associated with a marked enhancement in hydroxyproline levels and
supported the histological evidence that these mice exhibited much
greater subepithelial fibrosis.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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In the present study, chronic airway changes were observed in mice
sensitized to soluble A. fumigatus antigens (using a
standardized sensitization protocol)12
and then given one
intratracheal challenge with 5 x 106A. fumigatus conidia. The airway changes included airway
hyperresponsiveness, mucus cell hyperplasia, and peribronchial
fibrosis, and all of these features of chronic allergic airway disease
were evident at day 30 after conidia challenge. Interestingly, these
features were not present in nonsensitized mice at day 30 after
conidia. We also examined the cytokine profile associated with both
conidia groups and observed that the inflammatory response in the
sensitized group was characterized by significant increases in IFN-,
IL-4, TGF-ß, and IL-13. Thus we have developed a chronic model of
allergic airway disease that will allow for subsequent studies directed
at defining the precise role of various soluble cytokine mediators
during airway remodeling.
Increasing evidence points to a major immunomodulatory role for
cytokines in allergic airway disease. Th2 cells are often isolated from
asthmatic subjects, leading to the speculation that these cells exert a
major role in asthma, but experimental data show that Th2-mediated
allergic lung inflammation is also associated with a vigorous
Th1-mediated response.32
Furthermore, Grunig and
colleagues28
have shown that IL-10 regulates both Th
responses during A. fumigatus-induced allergic airway
disease. In the present study, we examined the changes in Th1-type (ie,
IL-18 and IFN-) cytokines and IL-10 in whole lung homogenates from
nonsensitized and A. fumigatus-sensitized mice at various
times before and after the A. fumigatus conidia challenge.
No previous studies have addressed the role of IL-18 in experimental
allergic responses to A. fumigatus, but IFN- is elevated
during clinical ABPA.33
Elevations in IFN- are probably
of great significance in the model of chronic airway inflammation
described here because IFN- has been shown to prime alveolar
macrophages during allergic reactions to release inflammatory
cytokines.34
Given that IL-10 has a major suppressive role
during allergic airway responses to A.
fumigatus,28
it was interesting to note that whole
lung IL-10 levels were significantly inhibited in both groups at day 3
after conidia. There is no explanation for this decrease at present,
but it may be related to clinical findings showing that alveolar
macrophages have an increased capacity to release proinflammatory
cytokines and a reduced capacity to produce IL-10 during
asthma.35
Thus both conidia models were associated with
changes in Th1-type cytokines and IL-10, particularly during the early
stages after conidia challenge.
TGF-ß, IL-4, and IL-13 are cytokines of particular interest because of their potential role in the chronic airway changes observed in sensitized mice challenged with conidia. TGF-ß is a potent profibrotic cytokine that is greatly increased around asthmatic airways and is largely localized to infiltrating eosinophils.2 IL-13 partly utilizes components of the IL-4 receptor signaling pathway for MCP-1 generation by endothelial cells36 and ß1-integrin and vascular cell adhesion molecule-1 (VCAM-1) expression and MCP-1 generation by fibroblasts.37 Furthermore, the targeted pulmonary expression of IL-13 elicits an inflammatory response, goblet hyperplasia, subepithelial fibrosis, de novo cytokine synthesis, airway obstruction, and hyperresponsiveness.38 Thus the changes in whole lung levels of profibrotic and inflammatory cytokines such as TGF-ß and IL-13 presumably contribute to the chronic airway changes in A. fumigatus-sensitized mice after conidia challenge.
In conclusion, we have developed a chronic model of allergic airway disease that will permit a detailed examination of the mechanisms that lead to persistent airway hyperresponsiveness, goblet cell hyperplasia, and peribronchial fibrosis. In particular, further investigations are planned to address the role of cytokines in the chronic airway changes associated with this model.
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Footnotes |
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Supported by an American Lung Association Research grant (CMH) and National Institutes of Health grants HL35276 (SLK), HL31963 (SLK), and AI36302 (SLK).
Accepted for publication October 2, 1999.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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potentiates the release of TNF-
, and MIP-1 by alveolar macrophages during allergic reactions. Am J Respir Cell Mol Biol 1999, 20:407-412, granulocyte-macrophage colony-stimulating factor, and interferon- release from alveolar macrophages in asthma. Am J Respir Crit Care Med 1998, 157:256-262 and Stat6 phosphorylation. Immunology 1997, 91:450-457[Medline]
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M. M. Kelly, R. Leigh, P. Bonniaud, R. Ellis, J. Wattie, M. J. Smith, G. Martin, M. Panju, M. D. Inman, and J. Gauldie Epithelial Expression of Profibrotic Mediators in a Model of Allergen-Induced Airway Remodeling Am. J. Respir. Cell Mol. Biol., February 1, 2005; 32(2): 99 - 107. [Abstract] [Full Text] [PDF]
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Y. Hernandez, S. Arora, J. R. Erb-Downward, R. A. McDonald, G. B. Toews, and G. B. Huffnagle Distinct Roles for IL-4 and IL-10 in Regulating T2 Immunity during Allergic Bronchopulmonary Mycosis J. Immunol., January 15, 2005; 174(2): 1027 - 1036. [Abstract] [Full Text] [PDF]
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M. C. Noverr, N. R. Falkowski, R. A. McDonald, A. N. McKenzie, and G. B. Huffnagle Development of Allergic Airway Disease in Mice following Antibiotic Therapy and Fungal Microbiota Increase: Role of Host Genetics, Antigen, and Interleukin-13 Infect. Immun., January 1, 2005; 73(1): 30 - 38. [Abstract] [Full Text] [PDF]
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 R. Leigh, D. S. Southam, R. Ellis, J. N. Wattie, R. Sehmi, Y. Wan, and M. D. Inman T-cell-mediated inflammation does not contribute to the maintenance of airway dysfunction in mice J Appl Physiol, December 1, 2004; 97(6): 2258 - 2265. [Abstract] [Full Text] [PDF]
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 R. Leigh, R. Ellis, J. Wattie, D. D. Donaldson, and M. D. Inman Is Interleukin-13 Critical in Maintaining Airway Hyperresposiveness in Allergen-challenged Mice? Am. J. Respir. Crit. Care Med., October 15, 2004; 170(8): 851 - 856. [Abstract] [Full Text] [PDF]
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M. C. Noverr, R. M. Noggle, G. B. Toews, and G. B. Huffnagle Role of Antibiotics and Fungal Microbiota in Driving Pulmonary Allergic Responses Infect. Immun., September 1, 2004; 72(9): 4996 - 5003. [Abstract] [Full Text] [PDF]
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T. Glaab, W. Mitzner, A. Braun, H. Ernst, R. Korolewitz, J. M. Hohlfeld, N. Krug, and H. G. Hoymann Repetitive measurements of pulmonary mechanics to inhaled cholinergic challenge in spontaneously breathing mice J Appl Physiol, September 1, 2004; 97(3): 1104 - 1111. [Abstract] |
0.05 compared
with values measured in both groups before the conidia challenge.
