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Division of Pulmonary, Critical Care, and Occupational Medicine, University of Iowa College of Medicine, and Veterans Administrations Medical Center, Iowa City, IA 52242
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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gene expression. DBA/2 mice resembled sensitive,
C57BL/6 mice if they received IL-12 augmentation therapy at the time of
Ag exposure. These findings were not limited to lung, since both
unstimulated and SR-stimulated spleen cells from C57BL/6 mice released
significantly more IL-12 than cells from DBA/2 mice. However, spleen
cells from DBA/2 mice made more IFN- when exposed to IL-12, than
cells from C57BL/6 mice. These results suggest that the IL-12 response
to Ag may modulate in part the expression of HP. |
Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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In prior studies, we used a well-described murine model to study HP. In
this model, mice exposed to the actinomycete, Saccharopolyspora
rectivirgula (SR; previously named Micropolyspora faeni
and Faeni rectivirgula), via nasal inhalation,
develop diffuse bronchoalveolitis and form granulomas in the lung
(7, 34). Using this model, we evaluated the role of IL-10 in modulating
the effect of the proinflammatory cytokines, IFN-, IL-1, and TNF.
Mice that could not produce IL-10 had more severe inflammatory changes
in the lung than wild-type littermates, and they exhibited increased
Ag-induced expression of the IFN-, IL-1, and TNF genes. When IL-10
was replaced, IL-10 knockout mice resembled their wild-type littermates
(34). In another study, using IFN- knockout mice (GKO), we showed
that IFN- is necessary for granuloma formation in HP. The GKO mice
did not develop the granulomatous inflammation. Replacement of IFN-
in the GKO mice resulted in expression of HP in lung similar to that in
wild-type littermates (7). The observations of these studies suggested
that expression of a Th1-type immune response might determine the
clinical expression of HP.
To further evaluate factors that might determine the expression of a
Th1-type immune response and expression of lung disease in HP, we took
advantage of prior studies that showed that various strains of mice
have differences in susceptibility to developing HP (8, 9, 10, 11). C57BL/6
mice are sensitive and DBA/2 mice are resistant to developing HP. Our
hypothesis for these studies was that these mouse strains differ in
their expression of one or more Th1-type cytokines in response to
inhaled Ag and that this determines in part the expression of HP. We
confirmed that, compared with resistant mice, a sensitive strain
develops a more severe granulomatous inflammatory response in the lung
with higher lung weights. The sensitive mice also express increased
amounts of lung IL-12 and IFN- mRNA. Associated with these changes,
they exhibit more lung TGF-ß, collagen I, and fibronectin mRNAs and
greater amounts of lung hydroxyproline. When given augmentation therapy
with IL-12, the resistant mice resemble sensitive mice. The strain
differences observed in these mice were not limited to lung, since
spleen cells from sensitive mice make more IL-12 than cells from the
resistant mice, but DBA/2 mice make more IFN- when stimulated with
IL-12. These observations suggest that the IL-12 response to Ag
determines in part the expression of HP in this murine model.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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C57BL/6 and DBA/2 mice were purchased from Harlan Sprague-Dawley Laboratories (Indianapolis, IN). Female mice, weighing 18 to 24 g, were used for these studies. They were housed in an Ag-free and virus-free environment at the University of Iowa Animal Care Unit and maintained on standard mouse chow and water ad libitum. All animal care and housing requirements set forth by the National Institutes of Health Committee on Care and Use of Laboratory Animal Resources were followed, and animal protocols were reviewed and approved by the Institutional Animal Care and Use Committee.
Antigen
Ag was prepared from a strain of SR obtained from American Type Culture Collection (catalogue no. 29034, Rockville, MD). It was grown in a trypticase soy broth in a 55°C shaking incubator for 4 days, centrifuged, and rinsed with distilled water three times. It was then homogenized and lyophilized. Ag was resuspended in pyrogen-free saline. A limulus amebocyte lysate assay from Sigma (St. Louis, MO) showed that this material was endotoxin free. Ag was also prepared, as described above, and grown in medium containing 14C-labeled amino acids (DuPont-New England Nuclear Research Products, Boston, MA).
Induction of HP
HP was induced by installing 30 µg of SR Ag in saline, intranasally, under light anesthesia, as we previously described (7, 34). The material was applied at the tip of the nose and inhaled involuntarily. This was performed for 3 consecutive days/week for 3 wk. This dose of Ag and the timing of exposures were chosen after preliminary studies showed that these methods were optimal for distinguishing between sensitive and resistant strains. To evaluate whether resistance to Ag was dose dependent, groups of mice were also treated with 90 µgof Ag. Mice were sacrificed by pentobarbital injection at various time points after the last exposure.
Bronchoalveolar lavage
After death, a 20-gauge catheter was inserted into the trachea. Bronchoalveolar lavage (BAL) samples were obtained by washing the lungs with three 1-ml aliquots of 0.9% saline. After centrifugation, BAL cell pellets were washed and resuspended in HBSS, and total cell counts were enumerated using a Coulter counter (Coulter, Hialeah, FL). Cytospin preparations were fixed and stained using Diff-Quick staining (Baxter, McGaw Park, IL). Differential cell counts were made on 200 cells using standard morphologic criteria to identify the cells as neutrophils, eosinophils, lymphocytes, or macrophages (7).
Flow cytometry
Flow cytometry was performed with a Becton Dickinson FACScan (Becton Dickinson, San Jose, CA). CellQuest software (Becton Dickinson) was used for acquisition and analysis of data. A bitmap gate was placed around the lymphocyte population on the basis of forward and orthogonal light scatter. Cells falling within the lymphocyte gate were then analyzed in a FITC vs phycoerythrin dual parameter histogram, and percentages were generated with quadrant statistics. FITC-conjugated rat anti-mouse CD4 Ab and phycoerythrin-conjugated rat anti-mouse CD8a Ab were obtained from PharMingen (San Diego, CA). IgG isotype standards were also obtained for controls.
Lung index (weight)
Lungs were removed, trimmed of extraneous tissue, rinsed, and weighed. Lung indexes were calculated as described by Wilson et al. (8): lung index = [(lung weight/body weight) x test animal]/[(lung weight/body wight) x control animal].
Histologic evaluation
Lungs were perfused with 2% paraformaldehyde through the heart and trachea and fixed in 2% paraformaldehyde-PBS. The sections were embedded in paraffin, cut in 5-µm-thick sections, and stained with hematoxylin and eosin. The sections were evaluated by light microscopy. A histologic score for each lung was determined according to the following criteria: 0 = no lung abnormality, 1 = presence of inflammation and granulomas involving <10% of the lung parenchyma; 2 = lesions involving 10 to 30% of the lung; 3 = lesions involving 30 to 50% of the lung; and 4 = lesions involving >50% of the lung (7). The slides were evaluated without knowledge of the type of mouse or exposure to Ag. The area covered by an eyepiece grid (0.99 x 0.99 mm using x100 magnification) was judged to be normal or abnormal. An average of 200 fields were evaluated for each mouse (7).
Northern analysis
Total lung RNA was prepared using the guanidine thiocyanate
(GITC) extraction and cesium chloride centrifugation method of Chirgwin
et al. (12), as modified by Maniatis et al. (13). The RNA was
fractionated on a 1.5% agarose gels containing 2.2 M formaldehyde by
the method of Lehrach and co-workers (14). The gels were stained with
ethidium bromide and destained overnight in 0.1% ammonium acetate to
assess RNA integrity and equivalent loading. Escherichia
coli 23S and 16S mRNA served as standards. Subsequently, the RNA
was transferred to GeneScreen Plus (New England Nuclear, Boston, MA)
following the manufacturer’s specifications and then UV cross-linked
to the nylon membrane. Fixed membranes were prehybridized for 12 to
24 h at 42°C in a solution of 50% formamide, 1 M NaCl, 1x
Denhardt’s solution, 0.05 M Tris (hydroxymethyl) aminomethane (Tris),
1% SDS, and 10% dextran sulfate. The membranes were hybridized with
fresh solution at 42°C with a 32P-labeled cDNA probes for
murine TNF, IL-1, and IL-12, obtained from Clontech (Palo Alto, CA).
TGF-ß1 probe was obtained from American Type Culture Collection
(Rockville, MD). Other probes were generously provided as noted: murine
1(I) procollagen provided by Dr. Benoit deCrombrugghe and rat
fibronectin by Dr. Richard Hynes. Following hybridization, the filters
were washed twice at room temperature in 1x SSC, followed by two
rinses at 65°C in 1x SSC/1% SDS, and a final room temperature wash
in 0.1x SSC. Hybridized membranes were then exposed to
radiographic film.
RT-PCR
In prior studies (7), we noted that IFN- mRNA cannot be
detected in mouse lung by Northern analysis. Thus, we used the method
of RT-PCR to detect this mRNA. Total lung RNA was prepared as described
above. It was then treated with DNase and reverse transcribed using
murine Moloney leukemia virus reverse transcriptase (MMLVRT) enzyme in
a total reaction volume of 50 µl. PCR was performed on the resultant
cDNA, using primers specific for IFN- (purchased from Clontech) and
the PCR products were analyzed on a 3% agarose gel and visualized with
an ethidium bromide stain. The PCR product was then transferred from
the agarose gel to a membrane, hybridized with the appropriate
32P-labeled cDNA probe, and analyzed following
autoradiography.
Hydroxyproline studies
The total lung hydroxyproline was determined as previously described (15). Briefly, lung was homogenized with cold TCA followed by hydrochloric acid. Chloramine-T was added, followed by perchloric acid and p-dimethyl-aminobenzaldehyde. Color change was assessed by spectrophotometry and compared with hydroxyproline standard.
IL-12 augmentation therapy
Recombinant murine IL-12 was purchased from Genzyme (Cambridge, MA). It had a sp. act. of 5 x 105 U/mg. The material was diluted in PBS with 1% BSA. Groups of DBA/2 mice were given an i.p. injection of 200 ng of IL-12 (or diluent) in 0.2 ml of diluent daily just before each exposure to Ag for the first 2 wk of the 3-wk period that the animals were exposed to Ag.
IL-12 and IFN- release from spleen cells
Spleens were removed from naive C57BL/6 and DBA/2 mice and
single cell suspensions isolated in RPMI 1640 medium (Life
Technologies, Grand Island, NY) containing 1% FCS (HyClone, Logan,
UT). Cells were washed twice, suspended at 5 x
106 cells/ml in RPMI 1640 medium containing 5% FCS,
and subsequently plated in aliquots of 1 ml in 12-well plates. To
induce cytokine release, cells were stimulated with 1 µg/ml of SR Ag.
As a positive control, we used Con A (25 µg/ml). In some instances,
cells were primed with 100 U/µl of rIFN- (Genzyme) for 24 h
and then stimulated with 1 µg/ml of LPS obtained from Sigma as an
additional positive control. Abs to IL-10 (Genzyme; 1 µg/ml) and IL-4
(Genzyme; 1 µg/ml) were also used. Plates were then incubated for
24 h at 37°C in 5% carbon dioxide. Supernatants were harvested,
and IL-12 was measured by ELISA (Genzyme). Cells were also stimulated
with 5 µg/ml of SR Ag, 1 µg/ml of recombinant mouse IL-12
(Genzyme), or both. Supernatants were harvested, and IFN- was
measured by ELISA (Genzyme). To insure that there were equal numbers of
adherent cells in the spleen populations of C57BL/6 and DBA/2 mice,
these experiments were repeated using only adherent cells. In these
studies, 15 x 106 cells were allowed to adhere to the
plate for 1 h. Subsequently, nonadherent cells were removed. The
adherent cells were then stimulated as described above, and
supernatants were harvested after 24 h. The protein content of the
wells was determined with the Coomassie blue method (16). For these
studies, IL-12 and IFN- release is expressed as picograms of IL-12
or IFN- per microgram of protein.
Statistics
Statistical analysis was performed using an unpaired (two-tailed) t test. Values are expressed as the mean ± SEM. The 95% confidence limit was taken as significant (p < 0.05). Calculations were performed using the StatView 4.01 (Abacus Concepts, Berkeley, CA) statistical analysis program.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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C57BL/6 mice, but not DBA/2 mice, had an increase in lung index
after exposure to low dose Ag (30 µg), as shown in Figure 1
. They also had a greater amount of
granulomatous inflammatory changes after exposure to Ag, as illustrated
in Figure 2. The C57BL/6 mice had more
diffuse inflammatory changes with granuloma formation, while the DBA/2
mice tended to have peribronchial lymphocytic infiltration, as shown in
Figure 3. These results are quantitated
in Figure 4. These differences between
C57BL/6 and DBA/2 mice were dose dependent. When C57BL/6 and DBA/2 mice
were exposed to 90 µg of SR, no change was seen in the histology
score for C57BL/6 mice compared with that using the lower dose of Ag.
However, DBA/2 mice expressed more granulomatous inflammation in the
lungs with the higher dose of Ag than with the lower dose of Ag. With
the higher dose of Ag, the histology score of the DBA/2 mice was not
different from that of the C57BL/6 mice (not shown).
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To exclude the possibility that the differences in susceptibility to HP seen in the mice were due to different amounts of Ag delivered to the lungs, we exposed the sensitive and resistant mice to Ag labeled with 14C and counted the radioactivity in lung homogenates. There was not a significant difference between the two strains of mice (not shown).
Comparison of BAL cells in sensitive and resistant strains of mice
Both C57BL/6 and DBA/2 mice had an increase in inflammatory cells
in BAL fluid 4 days after exposure to low dose Ag, as shown in Figure 5. The number of cells in BAL fluid in
the two strains was not different. After Ag exposure, most of the cells
were macrophages, but the C57BL/6 mice had more lymphocytes, as shown
in Table I. These lymphocytes were more
commonly CD4+ than CD8+ cells. These
observations suggest that both strains of mice respond to low dose Ag,
but the response to Ag in the resistant mice does not trigger a
granulomatous inflammatory response that can be detected
histologically. In Figure 6A
is shown the time course for cells in BAL fluid from the day of
exposure to SR until 7 days after exposure. Both strains had the
greatest number of cells on the day of exposure, and then the numbers
of cells decreased with time. As shown in Figure 6B,
neutrophils were most prominent immediately after exposure, and the
numbers decreased over time. There was a more sustained neutrophil
response in the DBA/2 mice during the first 3 days after exposure.
There were also significantly more lymphocytes in the C57BL/6 mice on
days 1 and 3 after the last exposure (results not shown). These
observations suggest that more lymphocytes are recruited into the lungs
of sensitive mice than resistant ones.
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Table II compares total leukocyte
counts and differential counts in C57BL/6 and DBA/2 mice. There was no
difference in the numbers of cells, including lymphocytes, between the
two strains nor was there any difference in the percentages of
CD4+ cells and CD8+ cells.
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Both C57BL/6 and DBA/2 mice had similar increases in lung TNF and
IL-1 mRNAs after low dose exposure to Ag. In contrast, the C57BL/6 mice
had a greater increase in IL-12 and IFN- mRNAs compared with DBA/2
mice (Figs. 7 and
8). These cytokine mRNAs were
also evaluated at other time points from 1 day after the last exposure
to 7 days after the last exposure. Only the time point with the peak
expression of mRNAs is shown for both strains of mice. These results
show that both sensitive and resistant strains of mice respond to Ag by
increasing expression of mRNAs for the proinflammatory cytokines IL-1
and TNF. This by itself does not appear to trigger granuloma formation
in the resistant strain of mice. Sensitive, C57BL/6 mice develop a
greater up-regulation of IL-12 and IFN- mRNAs compared with DBA/2
mice, and this is associated with the development of a granulomatous
inflammatory response in the lung. These observations are consistent
with our prior studies, which showed that IFN- is necessary for
granuloma formation in HP (7). With higher doses of Ag (90 µg), the
IL-12 responses are comparable in the two strains of mice (Fig. 9), suggesting that DBA/2 mice are able
to make IL-12.
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C57BL/6 mice had greater amounts of hydroxyproline in the lungs
after low dose Ag exposure compared with DBA/2 mice as shown in Figure 10. They also had increased expression
of mRNAs for collagen I, fibronectin, and TGF-ß (Fig. 11). These observations suggest that
the response to Ag in sensitive mice, but not that in resistant mice,
results in changes in extracellular matrix proteins.
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IL-12 is a potent inductor of IFN- production. Therefore, we
evaluated whether administration of exogenous IL-12 would permit a
resistant strain of mice to respond to low dose Ag and develop HP.
Groups of DBA/2 mice were treated (as described in Materials and
Methods) with IL-12 during Ag exposure. DBA/2 mice that
received IL-12 developed significantly more granulomatous inflammation
than DBA/2 mice exposed to Ag but not given IL-12 (Fig. 12). Mice exposed to saline alone or
given IL-12 alone did not have detectable amounts of inflammation.
These observations suggest that IL-12 is important for the development
of a granulomatous inflammatory response in this murine model of
HP.
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production by spleen cells
We next determined whether there were systemic differences in
production of IL-12 in sensitive and resistant mice. When spleen cells
from naive C57BL/6 and DBA/2 mice were exposed to SR Ag, the cells from
the C57BL/6 mice produced significantly more IL-12 than those from the
DBA/2 mice (Fig. 13A). Baseline,
unstimulated release of IL-12 was also greater in the C57BL/6 mice.
Both also responded to stimulation with Con A and to LPS after cells
had been primed with IFN-. However, the absolute amount of IL-12
was, again, significantly lower in the DBA/2 mice. This was also true
if only adherent spleen cells were evaluated, and the data were
expressed as IL-12 per milligrams of cell protein as shown in Figure 13B.
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A). When cells were
exposed to Abs to IL-10 along with SR, cells from C57BL/6 mice made
more IL-12 as shown in Figure 14B. This further supports the
importance of IL-10 as an anti-inflammatory cytokine in C57BL/6
mice as we have previously shown.
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, cells from both
C57BL/6 and DBA/2 mice responded to stimulation by IL-12 by making
IFN-. These observations suggest that the production of IL-12
itself, and not responses downstream of IL-12, distinguishes the
sensitive mice from the resistant mice.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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mRNAs with Ag
exposure. The sensitive mice also expressed more TGF-ß, collagen I,
and fibronectin mRNAs in their lungs after Ag exposure. There also was
more hydroxyproline in the lungs of Ag-exposed, sensitive mice. When
given augmentation therapy with IL-12, the resistant mice resembled
sensitive mice in their response to low dose Ag. With larger doses of
Ag, there was a similar response to Ag in the two strains of mice. To
determine whether the differences between sensitive and resistant
strains were limited to lung, we performed similar studies with spleen
cells. Spleen cells from DBA/2 mice produced less IL-12 than cells from
C57BL/6 mice, but they produced more IFN- when stimulated with
IL-12. These observations, as an aggregate, suggest that the IL-12
response to Ag determines at least in part the development of HP in
these two strains of mice. It is well documented in humans that there are different susceptibilities to developing HP. It has been estimated that in farmers lung disease between 5 and 15% of individuals that are exposed to Ag develop clinical disease (1, 2). Many individuals have precipitating Abs against thermophilic bacteria, suggesting exposure, but they are asymptomatic (1, 2, 3, 4). Some of these individuals and some that do not have precipitating Abs have lymphocytic alveolitis when BAL is performed (17). These observations suggest that exposed, asymptomatic subjects also respond in some manner to Ag. The reasons for the differences in clinical susceptibility to Ag are not well understood, but they are important in understanding the pathogenesis of HP.
Previous studies have identified differences in susceptibility to HP in various strains of mice. Wilson and colleagues used a lung index to screen several mouse strains for susceptibility to HP. They found that several mouse strains had an increase in lung index, suggesting the development of HP. Among these were C57BL/6 and C3H/He strains. DBA/2 mice had no change in lung index, suggesting resistance (8). Histology of lung tissue was not performed in this study. The findings of this study were used to select strains of mice for the present study. Donnelly and associates studied the influence of MHC genes on the expression of HP in mice. They found that mice expressing the k and b MHC haplotypes developed more severe lesions than mice expressing d or q haplotypes even when the MHC genes were expressed on a common genetic background (9). A study by Rossi et al. showed similar results with OVA-induced lung disease in mice (10). C57BL/6 mice have a b haplotype, and DBA/2 mice carry the d haplotype (11).
The Th1 and Th2 subsets of T cells are defined on the basis of their
pattern of production of cytokines (18). Th1 cytokines include IL-2,
IL-12, and IFN-. Th2 cytokines include IL-10, IL-4, IL-5, and IL-6.
In a murine model of experimental HP, Schuyler and associates showed
that Th1 cells were able to adoptively transfer HP (19). We have
previously shown that IFN- is important in the pathogenesis of HP
(7). When mice that do not produce IFN- are exposed to Ag, they do
not develop granulomatous inflammation. In addition, IL-10 dampens the
expression of IFN- and the development of HP in wild-type mice (34).
Thus, Th1 responses are likely to be important in HP.
IL-12 is important for regulating many Th1 responses (20, 21). It can
be produced by T cells, macrophages/monocytes, and neutrophils and is
important for both the induction and the maintenance of Th1 responses
(20, 21, 22). It is also produced by APCs, such as dendritic cells and skin
Langerhans’ cells (21). The major cellular targets of IL-12 are T
cells, NK cells, and B cells (22). A major effect of IL-12 on these
cells is augmentation of the production of IFN- (23). One
consequence of a dampened IL-12 response to Ag might be insufficient
IFN- to support the development and/or maintenance of granulomatous
lung disease. The observations of this study would be consistent with
this hypothesis. In support of this hypothesis is a study by Caruso and
colleagues (24). They observed, using the hapten trinitrophenol, that T
cells from mice with the k MHC haplotype produce high levels of
IFN-, while T cells from mice with the d haplotype produce low
levels of IFN-, on re-exposure to the Ag.
The reason for the lack of an IL-12 response to low dose Ag in DBA/2
mice is not clear. It does not appear to be due to a total absence of a
cellular response to Ag, because these mice do develop a lymphocytic
alveolitis. They, therefore, resemble asymptomatic humans who have
lymphocytic alveolitis after Ag exposure (17). The level of response in
the DBA/2 mice is clearly dose related, since the DBA/2 mice develop
granulomatous inflammation when exposed to higher concentrations of Ag.
A total lack of response by macrophages to low dose Ag also does not
appear to be a reason for the difference, since both strains of mice
express similar amounts of IL-1 and TNF mRNAs in response to Ag. IL-1
and TNF are both known to be important components of the granulomatous
response to Ag (25). It is likely that the lack of a granulomatous
inflammatory response in DBA/2 mice is due to a defect in the
production of IL-12, since DBA/2 mice develop lung disease similar to
that in sensitive mice when given IL-12 augmentation therapy. In
addition, spleen cells from DBA/2 mice are able to make IFN- when
stimulated with IL-12, and combined stimulation with both IL-12 and SR
leads to greater IFN- production than stimulation with IL-12 alone.
Our findings that spleen cells from DBA/2 mice release less IL-12 in
response to stimulation with SR, Con A, or combined stimulation with
IFN- and LPS support the hypothesis that the response to Ag in DBA/2
mice is related to an intrinsic defect in the production of IL-12. This
could be due to intrinsic differences in the IL-12 gene itself that
result in different levels of expression (26) or to an alteration in
upstream factors that regulate expression of the gene.
There also may be a relationship between the type of Ag and the
induction of a Th1- or Th2-type response. This is suggested by a study
by Rempel and associates, who observed that C57BL/6 mice develop a Th2
response when immunized with OVA. When given IL-12, these animals
increase the production of IFN- and modify the response to Ag (27).
In other studies, treatment with IL-12 has also been shown to change
the response to Ag. In murine models of bacterial and fungal
infections, treatment with IL-12 increased morbidity and mortality
(28). The same has been shown in autoimmune disease models
(29).
The cytokine environment at the time of stimulation is also thought to be important for the differentiation of the type of Th cell response. To support this, Williamson and associates have recently shown, in a model of graft-vs-host disease (GVHD), that C57BL/6 mice develop an acute, lethal Th1-mediated GVHD, but DBA/2 mice develop a Th2-dependent chronic GVHD. If C57BL/6 mice are treated with anti-IL-12 Abs, they switch to a Th2 response (30). The dose of Ag can also play a role in determining the type of immune response. This has been demonstrated in a model of Leishmania major infection (31) and in a model of herpes simplex virus infection (32, 33). Our studies, which show that exposure to IL-12 at the time of Ag exposure or an increase in the dose of Ag can change the response of resistant mice to Ag, are consistent with these prior studies.
Whatever the mechanisms that determine sensitivity to HP in these strains of mice, the present studies suggest that this murine model will be useful to further dissect the genetics and/or mechanisms of susceptibility to HP. The observations are highly relevant to human disease, since there are marked individual differences in the expression of clinical disease in individuals exposed to inhaled organic Ags.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Gunnar Gudmundsson, University of Iowa College of Medicine, GH C-321, 200 Hawkins Dr., Iowa City, IA 52242. E-mail address:
3 Abbreviations used in this paper: HP, hypersensitivity pneumonitis; SR, Saccharopolyspora rectivirgula; GKO, interferon- knockout; BAL, bronchoalveolar lavage; GVHD, graft-versus-host disease.
Received for publication September 8, 1997. Accepted for publication March 23, 1998.
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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H. J. Kim, H. Y. Kim, B. K. Kim, S. Kim, and D. H. Chung Engagement of Glucocorticoid-Induced TNF Receptor Costimulates NKT Cell Activation In Vitro and In Vivo J. Immunol., March 15, 2006; 176(6): 3507 - 3515. [Abstract] [Full Text] [PDF]
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J. N. Fink, H. G. Ortega, H. Y. Reynolds, Y. F. Cormier, L. L. Fan, T. J. Franks, K. Kreiss, S. Kunkel, D. Lynch, S. Quirce, et al. Needs and Opportunities for Research in Hypersensitivity Pneumonitis Am. J. Respir. Crit. Care Med., April 1, 2005; 171(7): 792 - 798. [Abstract] [Full Text] [PDF]
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D. G. Morris Gold, Silver, and Bronze: Metals, Medals, and Standards in Hypersensitivity Pneumonitis Am. J. Respir. Crit. Care Med., October 15, 2003; 168(8): 909 - 910. [Full Text] [PDF]
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Y. Matsunaga, Y. Usui, and Y. Yoshizawa TA-19, a Novel Protein Antigen of Trichosporon asahii, in Summer-type Hypersensitivity Pneumonitis Am. J. Respir. Crit. Care Med., April 1, 2003; 167(7): 991 - 998. [Abstract] [Full Text] [PDF]
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N. S. Butler, M. M. Monick, T. O. Yarovinsky, L. S. Powers, and G. W. Hunninghake Altered IL-4 mRNA Stability Correlates with Th1 and Th2 Bias and Susceptibility to Hypersensitivity Pneumonitis in Two Inbred Strains of Mice J. Immunol., October 1, 2002; 169(7): 3700 - 3709. [Abstract] [Full Text] [PDF]
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J. Todt, J. Sonstein, T. Polak, G. D. Seitzman, B. Hu, and J. L. Curtis Repeated Intratracheal Challenge with Particulate Antigen Modulates Murine Lung Cytokines ,2 J. Immunol., April 15, 2000; 164(8): 4037 - 4047. [Abstract] [Full Text] [PDF]
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E. Israel-Assayag, M. Fournier, and Y. Cormier Blockade of T Cell Costimulation by CTLA4-Ig Inhibits Lung Inflammation in Murine Hypersensitivity Pneumonitis J. Immunol., December 15, 1999; 163(12): 6794 - 6799. [Abstract] [Full Text] [PDF]
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H. Yamasaki, M. Ando, W. Brazer, D. M. Center, and W. W. Cruikshank Polarized Type 1 Cytokine Profile in Bronchoalveolar Lavage T Cells of Patients with Hypersensitivity Pneumonitis J. Immunol., September 15, 1999; 163(6): 3516 - 3523. [Abstract] [Full Text] [PDF]
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G. Gudmundsson, M. M. Monick, and G. W. Hunninghake Viral Infection Modulates Expression of Hypersensitivity Pneumonitis J. Immunol., June 15, 1999; 162(12): 7397 - 7401. [Abstract] [Full Text] [PDF]
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E. ISRAËL-ASSAYAG, A. DAKHAMA, S. LAVIGNE, M. LAVIOLETTE, and Y. CORMIER Expression of Costimulatory Molecules on Alveolar Macrophages in Hypersensitivity Pneumonitis Am. J. Respir. Crit. Care Med., June 1, 1999; 159(6): 1830 - 1834. [Abstract] [Full Text]
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