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Departments of
*
Pathology and
Internal Medicine, Division of Pulmonary and Critical Care, University of Michigan Medical School, Ann Arbor, MI 48109; and
Gladstone Institute of Cardiovascular Disease, University of California, San Francisco, CA 94141
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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At least four groups of chemotactic cytokines or chemokines
distinguished by the C, CC, CXC, or CXXXC motifs have been shown to
have roles in diverse events such as host defense, inflammation,
angiogenesis, hemopoiesis, and leukocyte chemotaxis (6).
All chemokines activate a wide array of immune and nonimmune cells via
unique G protein-coupled receptors. However, the CCRs have garnered
recent attention because of the unique roles some of these receptors
exert in the binding of HIV-1 to target cells (7). CCRs
have also received attention in fungus-induced diseases as it has been
shown that CCR1 and CCR5, receptors for macrophage inflammatory
protein-1 
and RANTES, were necessary for the containment of
Asperigillus fumigatus (8) and
Cryptococcus neoformans (9), respectively.
However, the role of CCR2, a major CCR involved in the recruitment and
activation of mononuclear (10, 11) and polymorphonuclear
(12) cells, has not been previously examined during
pulmonary responses to fungus. The primary agonist of CCR2 is monocyte
chemoattractant protein
(MCP)3-1 although
other lesser agonists of this receptor include MCP-2, 3, 4, and 5
(13). MCP-1 has been implicated in a wide array of
diseases including atherosclerosis, fibrosis, and granulomatous
lung disease (13).
Using a recently developed chronic model of allergic airway disease characterized by profound airway inflammation, hyperresponsiveness, and remodeling due to the intrapulmonary introduction of A. fumigatus conidia into A. fumigatus-sensitized mice (14), we addressed the following question: Does CCR2 modulate the allergic response of the host in this model? In this study, the airway inflammatory, resistance, and remodeling events in normal mice (CCR2+/+) were compared with those of mice with a targeted disruption of CCR2 (CCR2-/-). This study showed that CCR2-/- mice failed to adequately clear A. fumigatus Ags from their lungs and, as a consequence, experienced an exuberant inflammatory and remodeling response.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Breeding pairs of CCR2+/+ and CCR2-/- mice were originally provided by Dr. Israel Charo (Gladstone Institute, University of California, San Francisco, CA), and a breeding colony containing both mouse genotypes was maintained under specific pathogen-free conditions in the University Laboratory of Animal Medicine facility. As previously described, CCR2-/- mice were born at the expected Mendelian ratios and showed no evidence of abnormal growth patterns (15). CCR2+/+ and CCR2-/- mice were generated from mating homozygous mice of the same genetic background (C57BL/6 x 129Sv) and were intercrossed for five to seven generations. Prior approval for mouse usage in this study was obtained from the University Laboratory of Animal Medicine facility. Sensitization of mice to a commercially available preparation of soluble A. fumigatus Ags was performed as previously described in detail (14). Briefly, mice received an i.p. and s.c. injection of soluble A. fumigatus Ags dissolved in IFA. Two weeks after systemic sensitization, each mouse received a weekly intranasal challenge with A. fumigatus Ag to localize the allergic responsiveness to the airways. One week after the third intranasal challenge, each mouse 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. This dose of conidia has previously been shown to be nonlethal in normal mice (8). The sensitization status of each mouse was confirmed by the presence of IgE in serum (data not shown). A. fumigatus-sensitized CCR2+/+ and CCR2-/- mice received 5.0 x 106 A. fumigatus conidia suspended in 30 µl of 0.1% Tween 80 via the intratracheal route (14).
Measurement of bronchial hyperresponsiveness
Immediately before and at days 3, 7, and 30 after the intratracheal A. fumigatus conidia challenge, bronchial hyperresponsiveness to methacholine (10 µg, i.v.) was assessed in a Buxco plethysmograph (Buxco, Troy, NY) as previously described (16). Sodium pentobarbital (0.04 mg/g of mouse body weight; Butler, Columbus, OH) was used to anesthetize mice before their intubation, and ventilation with a Harvard pump ventilator (Harvard Apparatus, Reno, NV) (16). Immediately following the assessment of airway hyper-responsiveness, a bronchoalveolar lavage (BAL) was performed using 1 ml of filter-sterilized normal saline. Approximately 500 µl of blood removed from each mouse was centrifuged at 15,000 rpm for 10 min to yield serum. Finally, whole lungs were dissected from each mouse and snap frozen in liquid N2 or fixed in 10% formalin for histological analysis (see below).
Morphometric analysis of leukocyte accumulation in BAL samples
Macrophages, neutrophils, eosinophils, and lymphocytes were quantified in BAL samples cytospun (Shandon Scientific, Runcorn, U.K.) onto coded microscope slides as previously described. These slides were then subjected to a Wright-Giemsa differential stain, and the average number of each cell type was determined after counting a total of 300 cells in 10–20 high-powered fields (1000x) per slide. A total of 1 x 106 BAL cells were cytospun onto each slide to compensate for differences in cell retrieval.
ELISA analysis
Murine MCP-1, MCP-3, IL-4, IFN-
, IL-5, IL-13, RANTES,
eotaxin, and macrophage-derived chemokine (MDC) protein levels were
determined in 50-µl samples from whole lung homogenates using a
standardized sandwich ELISA technique previously described in detail
(17). Each ELISA was screened to ensure the specificity of
each Ab used. Recombinant murine cytokines and chemokines 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. Serum levels of IgE were
analyzed using complementary capture and detection Ab pairs for IgE
(PharMingen, San Diego, CA) and an ELISA performed according to the
manufacturer’s directions. Duplicate sera samples were diluted to
1:100, IgE levels in each were calculated from OD readings at 492 nm,
and IgE concentrations were calculated from a standard curve generated
using recombinant IgE (5–2000 pg/ml).
Whole lung histological analysis
Whole lungs from nonsensitized and A. fumigatus-sensitized mice before and after A. fumigatus conidia challenge were fully inflated with 10% formalin, dissected, and placed in fresh formalin for 24 h. Routine histological techniques were used to paraffin-embed the entire lung, and 5-µm sections of whole lung were stained with one of Gomori methanamine silver (GMS), Masson trichrome, and hematoxylin and eosin (H&E). Inflammatory infiltrates and structural alterations were examined around blood vessels and airways using light microscopy at a magnification of x400.
Hydroxyproline assay
Total lung collagen levels were determined using a previously described assay (18). Processed whole lung samples were added in triplicate to 96-well plates and then incubated at room temperature for 20 min before the addition of 100 µl of Ehrlich’s solution (Aldrich, Milwaukee, WI). These samples were subsequently incubated for 15 min at 65°C and cooled to room temperature before the 96-well plate was read at 550 nm in an ELISA plate scanner. Hydroxyproline concentrations per lung were calculated from a standard curve of known hydroxyproline concentrations of 0–100 µg/ml.
Statistical analysis
All results are expressed as mean ± SEM. 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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The whole lung levels of MCP-1 and MCP-3 were measured
before and at various times after an intrapulmonary challenge
of A. fumigatus conidia in
CCR2+/+ and CCR2-/- mice.
As shown in Table I
, the highest levels of
both CCR2 agonists in CCR2+/+ mice were measured
before the conidia challenge. At days 3 and 7 after the conidia
challenge, MCP-1 and MCP-3 levels were marginally lower than starting
levels, but the greatest decrease in these chemokines was observed at
day 30 after the conidia challenge. However, it is important to note
that levels of MCP-1 were 
8-fold lower in nonsensitized mice
compared with A. fumigatus-sensitized mice before the
conidia challenge. In addition, MCP-3 levels in whole lung samples from
nonsensitized CCR2+/+ mice were below the limit
of detection of the ELISA (50 pg/ml). Overall, MCP-1 and MCP-3 levels
were detected in greater quantities in CCR2-/-
mice than in their wild type counterparts. Interestingly, levels of
both chemokines in whole lung samples followed a downward trend during
the course of the conidia challenge. One exception was observed at day
3 after conidia, when the highest levels of MCP-1 in whole lung samples
were observed in CCR2-/- mice. Once again,
levels of MCP-1 and MCP-3 were markedly lower in nonsensitized
CCR2-/- mice compared with
CCR2-/- before and after the conidia challenge.
Taken together, these data suggested that lung levels of CCR2 agonists
were markedly increased in A. fumigatus-sensitized mice
compared with nonsensitized mice, and the presence of CCR2 was not
necessary for the induction of MCP-1 and MCP-3.
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Increased IgE is a hallmark of hypersensitivity to A.
fumigatus (19, 20). Measurement of serum IgE levels
in this study revealed a marked difference in the generation of IgE by
the two groups after their challenge with A. fumigatus
conidia (Fig. 1).
CCR2-/- mice had significantly greater total
serum IgE levels compared with CCR2+/+ mice
before conidia challenge. In both groups, peak IgE levels were measured
at day 3 after conidia, but 2.5-fold far greater levels of IgE were
evident in CCR2-/- mice compared with the
CCR2+/+ group at this time (Fig. 1). A similar
difference between the groups was noted at day 7, but IgE levels were
40-fold greater in the CCR2-/- group
compared with the other group at day 30 after conidia. Thus, these
results suggested that the introduction of A. fumigatus
conidia into A. fumigatus-sensitized
CCR2-/- mice greatly augmented the IgE response
to this fungus.
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Previous studies have shown that CCR2-/-
mice have significant defects in monocyte recruitment. Specifically,
these mice did not exhibit monocyte recruitment into the peritoneal
cavity in response to thioglycollate (10, 15), nor did
these mice clear the intracellular bacteria, Listeria
monocytogenes (11). In this study, the absence of
CCR2 during an intrapulmonary challenge of A. fumigatus
conidia in A. fumigatus-sensitized mice had a minor effect
on recruitment of mononuclear cells into the airways as determined by
BAL cell counts (Fig. 2A).
Although significantly greater numbers of macrophages were present in
BAL samples from CCR2+/+ mice compared with
CCR2-/- mice at day 3 after the conidia
challenge, no differences between the two groups of mice were observed
at any other time. Recruited neutrophils are a critical part of the
first line of defense against A. fumigatus conidia because
of their ability to kill conidia and destroy Aspergillus
hyphae (21). Surprisingly, neutrophil recruitment into the
airways of CCR2-/- mice was the most adversely
affected following the intrapulmonary conidia challenge (Fig. 2B). In marked contrast to CCR2+/+
mice, these polymorphonuclear cells were largely absent from BAL
samples from CCR2-/- mice on day 3 after the
conidia challenge. Thus, these data suggested that the recruitment of
macrophages into the airways was only modestly affected by the absence
of CCR2, whereas neutrophil recruitment into the airways was severely
depressed in CCR2-/- mice following an A.
fumigatus conidia challenge.
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The survival of A. fumigatus-sensitized
CCR2-/- mice was not adversely affected
following an intrapulmonary challenge with 5.0 x
106 conidia (data not shown). Although this
observation suggested that CCR2-/- mice were
not developing invasive pulmonary aspergillosis disease
(22), it did not negate the possibility that A.
fumigatus conidia or cell wall components persisted in the lungs
of CCR2-/- mice. Therefore, GMS-stained whole
lung sections from CCR2-/- and
CCR2+/+ mice were examined histologically using
GMS staining at various times before and after the conidia challenge.
The GMS stain appears black in the presence of polysaccharide
components from the fungus cell wall. No qualitative difference in GMS
staining was observed between A. fumigatus-sensitized
CCR2+/+ and CCR2-/- mice
before the conidia challenge (not shown). At day 3 after conidia,
GMS-positive cells were present in lung sections from
CCR2+/+ mice (Fig. 3A), although intact conidia
were rarely detected. In contrast, whole conidia were apparent in
numerous cells in the lungs of CCR2-/- mice at
this time (Fig. 3B). At day 7 after conidia, few
GMS-positive cells were detected in CCR2+/+ mice
(Fig. 3C), but GMS staining was prominent in numerous
mononuclear cells in the lungs of CCR2-/- mice
(Fig. 3D). A profound difference between the two groups of
mice was also apparent when GMS-stained whole lung sections were
examined at day 30 after the conidia challenge.
CCR2+/+ mice completely lacked GMS-positive cells
at this time (Fig. 3E), whereas
CCR2-/- mice showed clear evidence of increased
GMS staining associated with mononuclear cells at days 30 postconidia
(Fig. 3F). Interestingly, the majority of the GMS staining
at day 30 after conidia in CCR2-/- mice was
associated with dense collections of mononuclear cells. However, the
invasive or hyphal forms of A. fumigatus were not observed
in lung sections from either group of mice at any time after the
conidia challenge. Thus, a histological survey suggested that CCR2 was
necessary for the clearance of A. fumigatus conidia and cell
wall components from the airways of challenged mice.
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Eosinophils and T cells have been implicated in the protracted
asthmatic responses observed in a large subset of patients with
hypersensitivity to A. fumigatus Ags (5, 20).
Eosinophilic inflammation around the airways poses a particularly
serious problem because of the disruptive proteolytic enzymes released
by these cells upon degranulation (1). Quantification of
eosinophils and lymphocytes in BAL samples revealed marked differences
between the two groups following conidia challenge (Fig. 4, A and B). No
eosinophils were observed in the BAL of either group before the conidia
challenge, but 3 days later significantly greater numbers of
eosinophils were observed in BAL from CCR2-/-
mice compared with BAL from CCR2+/+ mice (Fig. 4A). At later time points, the eosinophil numbers in the BAL
from CCR2-/- mice were similar to those
quantified in similar samples from CCR2+/+ mice.
Clinical and experimental data suggest that a T cell response directed
toward IL-4 and IL-5 is the major predisposing factor for the
development of allergic responses against Aspergillus in the
lung (1). Lymphocyte counts in BAL samples were also
markedly different between CCR2+/+ and
CCR2-/- mice following the conidia challenge
(Fig. 4B). At days 3 and 7 after conidia, 3-fold more
lymphocytes were present in CCR2-/- BAL
compared with CCR2+/+ BAL. Thus, the introduction
of conidia into previously sensitized CCR2-/-
mice significantly augmented the movement of eosinophils and
lymphocytes into the airways.
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Given the major changes in eosinophil and lymphocyte numbers in
the BAL samples from CCR2-/- mice, we next
examined whether the lung levels of cytokine and chemokines that
regulate the activation and/or recruitment of these cell types were
altered. IL-4 and IFN- are classically described as Th2 and Th1
cytokines, respectively (23). Temporal changes in IL-4 and
IFN- levels in whole lung homogenates from both groups of mice are
shown in Table II, and both cytokines were
detected at similar levels in both groups before and at various times
after the conidia challenge. It was of note that IL-4 levels were
equivalent in whole lung samples from CCR2+/+ and
CCR2-/- mice for the duration of the conidia
challenge period, but whole lung levels of IFN- were markedly lower
at day 30 after the conidia challenge compared with the earlier times
after conidia. Thus, these data suggested that IL-4 and IFN-
probably had minor roles in the exacerbation of the
Aspergillus-induced allergic disease in
CCR2-/- mice.
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A). IL-13 was present at
similar levels in both groups of mice before and at days 3 and 7 after
conidia (Fig. 5B). However, at day 30 after conidia, whole
lung homogenates from CCR2-/- mice contained
significantly greater levels of IL-13 compared with those detected in
whole lung from wild-type mice at this time.
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. Eotaxin levels were also
significantly elevated in lung from CCR2-/-
mice compared with CCR2+/+ mice before conidia
(Fig. 6A). In addition, RANTES levels were significantly
elevated at day 3 after the conidia challenge when statistically
compared with RANTES levels in CCR2+/+ mice at
the same times after conidia (Fig. 6B). Finally, the whole
lung levels of MDC were significantly higher in
CCR2-/- mice compared with
CCR2+/+ mice at days 3 and 30 after the conidia
challenge (Fig. 6C). Thus, these data demonstrated that the
generation of cytokines and chemokines with major stimulatory and
chemotactic effects on eosinophils and lymphocytes were significantly
enhanced in CCR2-/- mice following conidia
challenge.
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Increased airway resistance represents a key reversible hallmark
of clinical asthma, and in animal models of asthma an exaggerated
bronchoconstrictor response is observed in response to a bronchial
smooth muscle spasmogen that has little physiological consequence in a
nonsensitized animal (29). We have previously observed
that challenging mice previously sensitized to soluble A.
fumigatus Ags with the conidia markedly augments airway
hyperreactivity to methacholine challenge for up to 30 days
(14). In this study, airway hyperresponsiveness to a
methacholine challenge was measured in A.
fumigatus-sensitized CCR2+/+ and
CCR2-/- mice before and at various times after
conidia (Fig. 7). The dose of 10 µg of
methacholine had a negligible (i.e., less than a 2-fold increase)
effect on the airway resistance response in nonsensitized mice (Fig. 7, dashed line). Immediately before conidia challenge, both groups of mice
exhibited a similar 5-fold increase in airway resistance. However, at
days 3, 7, and 30 after conidia, airway resistance changes after a
methacholine challenge were significantly greater in
CCR2-/- mice compared with airway responses
measured in CCR2+/+ mice measured at the same
time. Thus, the airway responsiveness to the smooth muscle spasmogen
methacholine was clearly exacerbated in CCR2-/-
mice compared with CCR2+/+ mice at all times
after the conidia challenge.
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Another feature of an intrapulmonary conidia challenge in A.
fumigatus-sensitized mice is the increase in peribronchial
fibrosis (14). The presence of fibrosis in
CCR2+/+ and CCR2-/- mice
was first assessed using a histological method. As illustrated in Fig. 8A, Masson trichrome staining,
which highlights the presence of collagen, appears to be less prominent
around large airways from CCR2+/+ mice compared
with CCR2-/- mice shown in Fig.
8B at day 30 after the conidia challenge. Severe
peribronchial inflammation and goblet cell hyperplasia are also
prominent features of chronic allergic airway diseased due to
Aspergillus. Examination of H&E-stained lung sections from
CCR2+/+ mice (Fig. 8C) revealed goblet
cells in the epithelium but little evidence of peribronchial
inflammation. Goblet cells and a prominent peribronchial and
perivascular accumulation of mononuclear cells were evident in
CCR2-/- mice (Fig. 8D) at day 30
after the conidia challenge. In addition, numerous mononuclear cells
containing A. fumigatus (stained intensely green) were also
observed in close apposition to the inflamed airways in
CCR2-/- mice at this time (Fig. 8D).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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As revealed by in vivo gene-targeting technology, CCR2 is a major chemokine receptor that is required for macrophage recruitment and host defense against bacterial pathogens (10, 11, 15). MCP-1 appears to be the primary ligand that facilitates these CCR2-dependent functions (32). Given the requirement of CCR2 for the recruitment of macrophages in models of peritonitis, it was surprising to observe in this study that macrophage accumulation in the airways of CCR2-/- mice challenged with conidia was only modestly impaired. However, the mononuclear cells in the lungs of CCR2-/- mice were apparently unable to clear the polysaccharide components of A. fumigatus revealed by GMS staining. These findings were consistent with the previous findings of Kurihara et al. (11) who observed that CCR2-/- mice failed to clear the intracellular bacteria, Listeria monocytogenes. Why macrophages from CCR2-/- mice are unable to remove A. fumigatus from the airways is not presently apparent, but studies are presently directed at this dilemma. Conidia clearance, 30 days after challenge by macrophages, was also impaired in naive CCR2-/- mice; however, not to the same degree as A. fumigatus-sensitized mice. This observation would suggest that the primary phenotypic defect in CCR2-/- mice is the inability to efficiently clear conidia, whereas in the sensitized group, persistence of Ag leads to an exacerbated inflammatory response.
A. fumigatus poses the greatest danger in individuals with prolonged neutropenia or defects in neutrophil function, because the neutrophil is critical for the destruction of A. fumigatus conidia and hyphae (33). The absence of neutrophils in the airways of CCR2-/- mice was another striking feature of the allergic airway disease induced by Aspergillus in CCR2-/- mice. This defect was not a consequence of lowered circulating neutrophil numbers, as previous studies have shown that CCR2-/- mice have a normal compliment of circulating polymorphonuclear cells (15). The paucity of neutrophils may have been due to decreases in KC levels or a direct consequence of neutrophils lacking the ability to respond to MCP-1, which will promote the chemotaxis of neutrophils during acute (34) and chronic inflammatory conditions (12). Thus, these findings suggest that CCR2 has a major role in the recruitment of neutrophils during an intrapulmonary challenge with A. fumigatus conidia, and the paucity of neutrophils may explain the persistence of A. fumigatus in the airways of CCR2-/- mice.
Individuals that have been sensitized to A. fumigatus
demonstrate significantly increased levels of T cell-derived IL-4 and
IL-5, with low but significantly elevated levels of IFN-
(35). Experimental studies in mice have revealed that IL-4
and IL-5 have unique roles in the development of lung pathology due to
Aspergillus. Accordingly, IL-4-/-
mice exhibited similar lung inflammation as their wild-type
counterparts but completely lacked airway hyperresponsiveness to
bronchial spasmogens (36). In another murine study of
acute aspergillosis, eosinophilia resulted from the induction of IL-5
by soluble A. fumigatus Ags (37). Although no
apparent difference in whole lung levels of IL-4 or IFN- was
observed between CCR2-/- and
CCR2+/+ mice before or after the conidia
challenge, CCR2-/- mice had significantly
greater whole lung levels of IL-5 before and at days 3 and 7 after the
conidia challenge. The presence of IL-5 combined with increased
eotaxin, RANTES, and MDC levels may explain the enhanced movement of
eosinophils and lymphocytes into the BAL and the retention of these
cells around the airways of CCR2-/- mice. In
addition, all three chemokines have been shown to exert major effects
on airway hyperresponsiveness in an OVA-induced model of allergic
airway inflammation (27). Overall, these findings
demonstrate that allergic responses to A. fumigatus,
characterized by increased eosinophils and lymphocyte recruitment and
augmented IL-5, eotaxin, RANTES, and MDC levels, are significantly
enhanced in CCR2-/- mice.
Subepithelial fibrosis is another clinical feature of Aspergillus-induced airway disease and asthma that has been attributed to the eosinophilic and lymphocytic inflammation that persists around the airways of allergic individuals (1). Many of the previous studies in murine models of allergic aspergillosis have addressed the airway inflammation and hyperresponsiveness during allergic responses to soluble Aspergillus Ags, revealing roles for cytokines (38, 39, 40) and chemokines (16) in these processes. However, identification of the soluble factor(s) that contribute to all of the features of chronic allergic airway disease has been hampered by the lack of a model that recapitulates all of these clinical features. This study suggested that a number of cytokines and chemokines contributed to the augmented allergic responsiveness of CCR2-/- mice toward A. fumigatus conidia. However, of particular interest in this study was the finding that IL-13 and a C-C chemokine it strongly induces, namely MDC (41), remained significantly elevated in whole lung homogenates from CCR2-/- mice at day 30 after the conidia challenge, when profound airway inflammation, hyperresponsiveness, and peribronchial fibrosis were noted. These findings are important because of the prominent role that IL-13 has on a multitude of features associated with chronic asthma or allergic airway disease, including mononuclear and eosinophilic inflammatory recruitment, goblet cell metaplasia, eotaxin production, airway hyperresponsiveness, and subepithelial fibrosis (25, 26). Immunoneutralization of MDC during acute allergic airway inflammation was previously shown to prevent airway hyperreactivity and eosinophilia, suggesting that this chemokine was essential for the retention of leukocytes in the lung (28). Further studies are required to identify whether IL-13 and MDC are major participants in airway inflammation, hyperresponsiveness, and remodeling that follow an intrapulmonary conidia challenge in CCR2-/- and CCR2+/+ mice.
In conclusion, CCR2-/- mice are significantly more susceptible to the allergic consequences of an intrapulmonary A. fumigatus conidia challenge. The inability of these mice to completely clear antigenic components of A. fumigatus due to defects in macrophage activation and neutrophil recruitment appeared to account for the exacerbation of the chronic allergic airway disease induced by Aspergillus. Further studies are required to ascertain whether CCR2 agonists would aid in the rapid clearance of fungus from the airways of A. fumigatus-sensitized mice and thereby reduce the intensity of the allergic airway disease associated with this model.
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Cory M. Hogaboam, Department of Pathology, University of Michigan Medical School, Room 5214, Med Sci I, 1301 Catherine Road, Ann Arbor, MI 48109-0602.
3 Abbreviations used in this paper: MCP, monocyte chemoattractant protein; BAL, bronchoalveolar lavage; MDC, macrophage-derived chemokine; GMS, Gomori methanamine silver; H&E, hematoxylin and eosin.
Received for publication February 27, 2000. Accepted for publication June 8, 2000.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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in pulmonary host defense in murine invasive aspergillosis. J. Immunol. 162:1633. and interleukin-1 expression in a murine model of allergic bronchopulmonary aspergillosis. Lab. Anim. Sci. 46:42.[Medline]
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0.05 compared with values measured in
CCR2+/+ mice at the same time after the conidia
challenge.
