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*
Department of Respiratory Medicine, National Heart and Lung Institute, and Departments of
Infectious Diseases and Microbiology and
Histopathology, Imperial College School of Medicine, London, United Kingdom
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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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There is compelling evidence that CD4+ T cells
expressing the Th1 phenotype have an essential role in protection
during mycobacterial infection. Mice with targeted deletion of these
cells or the associated cytokines have markedly enhanced susceptibility
to tuberculosis (1, 2, 3, 4). In humans, tuberculosis is a
common consequence of HIV-associated depletion of
CD4+ T cells, and genetic polymorphisms affecting
the Th1 response result in hypersusceptibility to mycobacterial
infection (5, 6). In contrast, the significance of a Th2
response during mycobacterial infection is uncertain. In mice, the
initial phase of M. tuberculosis infection is dominated by a
Th1 response, with a Th2 response emerging after several weeks during
the subsequent chronic phase of the disease (7, 8). The
Th2 response may act to down-regulate Th1 cells, reducing the extent of
macrophage-mediated pathology, although perhaps at the same time
contributing to persistence of the infection and the risk of
reactivation (9). Alternatively, it has been proposed
that the coexistence of Th1 and Th2 responses may exacerbate tissue
damage by enhancing the pathological activity of TNF-
(10). The lack of any alteration in the course of M.
tuberculosis infection in mice deficient in IL-4, a major Th2
cytokine, raises the further possibility that Th2 cytokines might
represent a functionally irrelevant bystander response
(11). Similar uncertainty applies to human tuberculosis,
with contradictory reports describing the presence (12, 13) and absence of a Th2 component (14, 15). In two
recent studies, the magnitude of the Th2 response in tuberculosis
patients was found to correlate with the extent of disease progression,
although it was noted that the relationship between cause and effect
remained to be clarified (16, 17). The influence of an
underlying Th2 response on the outcome of mycobacterial infection may
be important in the context of age-related differences in
susceptibility to tuberculosis and during coinfection with mycobacteria
and intestinal parasites (18).
To investigate the contribution of the Th2 response to protection and
pathology, we wished to establish an experimental model in which we
could test the effect of deliberate addition of Th1 or Th2 cells during
a mycobacterial infection. We elected to do this using the DO11.10 TCR
transgenic model. The major T cell population in DO11.10 transgenic
mice is CD4+ with an 
TCR specific for
peptide 323–339 from OVA presented in the context of
I-Ad (19). Splenocytes from these
mice have a Th0 profile but can be programmed by appropriate in vitro
culture conditions to polarize toward a Th1 or Th2 phenotype (20, 21). DO11.10 T cells have been extensively characterized in a
range of immunological systems, including adoptive transfer models
(22, 23, 24). Our experimental model is based on adoptive
transfer of DO11.10 T cells together with challenge with recombinant
M. tuberculosis expressing the appropriate OVA epitope. In
addition to the attraction of using a well-defined immunological
system, this approach has the advantage of allowing us to distinguish
between Ag-specific and nonspecific effects, by carrying out parallel
infections with a recombinant strain of M. tuberculosis
expressing an irrelevant epitope.
We report on the contribution of Th1 and Th2 cells to protective and pathological responses in the lungs of mice challenged with OVA-coated beads or with OVA-expressing M. tuberculosis.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Mice transgenic for the DO11.10 TCR on a BALB/c
background, were obtained from F. Powrie at the Nuffield Institute
(Oxford, U.K.) and were originally developed by D. Loh at DNAX (Palo
Alto, CA) (19). These mice were bred and maintained at
Imperial College facilities at St. Mary’s campus and were checked for
transgenes by staining splenocytes with the anticlonotypic mAb KJ1–26
(25).
For adoptive transfer recipients, female nontransgenic BALB/c mice raised under specific pathogen-free conditions were purchased from Harlan OLAC (Bicester, U.K.). The mice were maintained for at least 1 wk and used for experiments at 7–8 wk of age.
Th1/Th2 cell culture protocol
Splenocytes from DO11.10 mice were isolated on a Ficoll-Paque
gradient (Pharmacia, Uppsala, Sweden) and cultured in 24-well culture
plates at 1 x 106 cells/ml in RPMI 1640
medium containing 5 mM HEPES buffer (Life Technologies, Renfrewshire,
U.K.), 10% FCS (ICN/Flow Laboratories, High Wycombe, U.K.), 100 U/ml
penicillin and 100 µg/ml streptomycin (Life Technologies), 2 mM
glutamine (Life Technologies), and 0.05 µM 2-ME (Sigma, Poole, U.K.).
Cells were cultured with OVA peptide (1 µM) together with 10 U/ml
IL-12 (R&D Systems, Abingdon, U.K.), and 10 µg/ml anti-IL-4
(PharMingen, San Diego, CA) to generate the Th1 phenotype. For Th2
cells, IL-12 and anti-IL-4 were replaced by 200 U/ml rIL-4
(Genzyme, Cambridge, MA). Cells were cultured in presence of
OVA alone for the Th0 phenotype. The OVA peptide, corresponding to
amino acids 323–339 of chicken OVA, was synthesized by Dr J. W.
Drifhout, Leiden University Medical Center (Leiden, The Netherlands) on
an ABIMED 422 synthesizer (ABIMED, Langenfeld, Germany) by the
simultaneous peptide synthesis method. The purity of the peptide was
verified by reverse-phase C18 high-pressure liquid chromatography
(Lichrospher; Merck, Darmstadt, Germany) and was shown to be routinely
over 75%. After incubation for 7 days at 37°C in humidified air
containing 5% CO2, cells were washed and either
injected into mice or cultured for a further 48 h in presence of 1
µM OVA and fresh APCs. Supernatants from the latter cultures were
used to characterize the T cell phenotype by measurement of IFN-
and
IL-5 by ELISA using paired Abs from PharMingen.
For adoptive transfer experiments, 5–7 x 106 cells that had been cultured under Th0, Th1, or Th2 conditions were injected into the tail vein of normal BALB/c mice, either alone or together with recombinant M. tuberculosis as described below, in a single injection of 0.2 ml in saline. When a mixed Th1/Th2 population was transferred, mice received 3 x 106 cells expressing each phenotype.
Preparation of OVA-coated beads
Cyanogen bromide-activated Sepharose 4B beads (Sigma) were swollen and coupled with OVA according to the manufacturer’s protocol. Briefly, 1 g of Sepharose beads were swollen in 1 mM HCl, then washed and suspended in 5 ml of coupling buffer (0.1 M NaHCO3, 0.5 M NaCl) containing 10 µM OVA. The mixture was rotated end-over-end on a rotary mixer overnight at 4°C. Excess peptide was removed by washing with 5 gel volumes of coupling buffer, and remaining reactive sites blocked with 0.1 M Tris HCl (pH 8) for 2 h. Beads were stored at 4°C in sterile PBS containing 0.05% NaN3. Beads were washed three times in sterile PBS and counted microscopically before injection.
OVA-coated or uncoated control beads (6000 per mouse) were introduced into normal BALB/c mice by i.v. injection as described by Chensue et al. (26). After 24 h, DO11.10 transgenic T cells were administered by a second i.v. injection. Mice were sacrificed on days 3, 7, and 21 postinjection. Pathology was monitored in the lungs, liver, and spleen. In some experiments, single cell suspensions of splenocytes were checked for expression of Th1 and Th2 phenotypes by culturing in presence of OVA for 48 h.
Recombinant M. tuberculosis and mycobacterial infection
M. tuberculosis H37Rv was grown with shaking at 37°C in Middlebrook 7H9 liquid medium supplemented with albumin, dextrose and catalase (ADC) as recommended by the manufacturer (Difco, Surrey, U.K.), or on Middlebrook 7H11 agar plates with oleic acid, albumin, dextrose, and catalase (OADC) supplement (Difco). When appropriate, hygromycin B (Boehringer Mannheim, Postfach, Germany) was added at 50 µg/ml. To generate recombinant constructs, oligonucleotides encoding amino acids 323–339 of chicken OVA and 126–138 of influenza virus hemagglutinin were cloned within the M. tuberculosis superoxide dismutase gene carried on an Escherichia coli mycobacteria shuttle plasmid as described previously (27). Plasmids were introduced into M. tuberculosis by electroporation, and hygromycin-resistant transformants characterized by electrophoretic analysis of the modified superoxide dismutase protein in sonicated preparation under denaturing and nondenaturing conditions (27). Confirmed recombinant clones were stored at -70°C as stock cultures containing 109 CFU/ml.
For infection experiments, thawed aliquots were mixed with DO11.10
cells and injected i.v. into mice at a challenge dose of 
2 x
106 CFU per mouse. An aliquot of the
suspension was plated on 7H11 agar to determine the precise infecting
dose. Groups of three mice representing each of the T cell/challenge
conditions were sacrificed on days 7 and 21 postinjection. Mice were
weighed, and lungs, liver, and spleen were removed for analysis.
To measure bacterial load, samples of infected tissue were weighed and homogenized in 3 ml saline in a stomacher. Homogenates were then plated on Middlebrook 7H11 agar plates in serial 10-fold dilutions in duplicate and incubated at 37°C for 2 wk. In some experiments, parallel sets of plates were prepared with and without hygromycin. Colonies were counted and the number of CFUs per organ was calculated.
Preparation of histological specimens
Organs were weighed before a small portion of each tissue was removed and fixed by immersion in 10% formal saline solution. Samples were embedded in paraffin wax, cut into sections, and mounted onto slides. Sections were then stained with hematoxylin to assess the extent of granuloma formation. In the Sepharose bead model, the size of the granulomas in lungs was measured by microscopy (x400 magnification) using image analyzer software. The inflammatory mass was determined by measurement of at least 20 granuloma for each condition. For M. tuberculosis infection, the lung infiltrates and granuloma formation were graded on a semiquantitative scale. Sections were coded and examined (by H.T.C.) without knowledge of experimental code.
Hydroxyproline assay
Hydroxyproline content was determined by the methods described by Stegemann and Stalder (28). Briefly, a portion of lungs was hydrolyzed in 6 N HCl at 100°C overnight. The sample was mixed with chloramine T solution and incubated for 20 min at room temperature. After incubation, aldehyde/perchloric acid solution was added and incubated at 60°C. After 15 min, the samples were cooled under tap water and absorbance was measured at 550 nm. The hydroxyproline content was expressed for whole lungs.
Isolation and RT-PCR amplification of mRNA
Small pieces of lung tissues were snap frozen in liquid nitrogen
and stored at -70°C. Total RNA from the frozen tissue was isolated
by homogenizing the organs in 0.5 ml of guanidine isothiocyanate. RNA
was extracted by a modification of acid-GTC phenol chloroform method as
described previously (29). First-strand cDNA synthesis
from 1 µg total RNA was conducted as described by Wangoo et al.
(30). The gene-specific primers were as follows:
-actin, 5'-ATGGATGACGATATCGCT-3' (sense),
5'-ATGAGGTAGTCTGTCAGGT-3' (antisense); IFN-,
5'-AACGCTACACACTGCATCT-3' (sense), 5'-AGCTCATTGAATGCTTGG-3'
(antisense); IL-13, 5'-GCCAGCCCACAGTTCTACAGC-3' (sense),
5'-GTGATGTTGCTCAGCTCCTCA-3' (antisense); collagen III,
5'-GGCTGATGTACACATGCTCC-3' (sense), 5'-GCTCAGAGTAGCACCATCAG-3'
(antisense). The predicted sizes of -actin, IFN-, IL-13, and
collagen III DNA products were 570, 398, 161, and 257 bp,
respectively.
To permit the same number of cycles in the PCR to be used for
measurement of each of the cDNAs, and, thus, for the assays to be
performed concurrently, cDNA was diluted 1:10 for IFN-, IL-13, and
collagen III, and 1:50 for -actin. A 5-fold correction factor was
subsequently used to calculate -actin ratios. The PCR amplification
mixture consisted of 10x PCR buffer, 1.25 mM
MgCl2, 1 U of Taq polymerase (Promega,
Southampton, U.K.), 200 µM deoxyribonucleosides (dATP, dGTP, dCTP,
and dTTP), 0.3 µM of each primer, and appropriate dilution of cDNA,
made up to 50 µl with sterile distilled water. Amplification was
conducted for 33 cycles in a DNA thermal cycler (Perkin-Elmer,
Beaconsfield, U.K.) under the following reaction conditions: 94°C for
1 min, 55°C for 2 min, and 72°C for 2 min. PCR products (15 µl)
were separated by electrophoresis on a 2% agarose gel containing
ethidium bromide. For visualization of the bands, the gel was
photographed under UV light.
Statistical analysis
Data were compared using the Mann-Whitney U test, and a p value of <0.05 was taken to be statistically significant. Error bars represent one SE from the mean.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Splenocytes from DO11.10 transgenic mice were cultured with OVA
for 1 wk in different cytokine environments to polarize them toward the
Th1 or Th2 phenotype. Cells were then washed, restimulated with peptide
alone for 48 h, and supernatants analyzed for IFN- and IL-5.
Table I
records a representative
experiment. Cells cultured in the absence of added cytokine had a Th0
profile, expressing minimal amounts of IFN- or IL-5. Culture in the
presence of IL-12 and anti-IL-4 Ab generated cells with a Th1
profile, characterized by a 70-fold increase in IFN- production.
Conversely, cells cultured in the presence of IL-4 expressed 20-fold
higher levels of IL-5, characteristic of a Th2 response.
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To test the stability of the Th1/Th2 polarization, splenocytes
from in vitro cultures were adoptively transferred into normal BALB/c
mice that had been injected with OVA-coated Sepharose beads 24 h
earlier. One week later, spleens were removed from the mice and
analyzed for expression of IFN- and IL-5 in response to
restimulation with OVA. The polarized T cells were found to have
retained their phenotype in vivo (Fig. 1). Spleen cells from mice receiving Th1
cells secreted IFN- when restimulated with OVA in vitro; spleen
cells from mice receiving Th2 cells produced a higher amount of
IL-5.
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We next wished to determine whether adoptively transferred DO11.10
T cells would influence immune responses in the lungs of recipient
animals. We initially explored a simple Sepharose bead model in which
OVA-coated beads were injected i.v. into BALB/c mice and embolized in
the lung. Th1, Th2, or a mixture of both Th1 and Th2 cells was
similarly injected via the tail vein 24 h later. Mice were
sacrificed after 7 days and the lungs removed for examination. On
histological analysis, it was evident that the granulomas that formed
around the beads in mice injected with Th1 or Th2 cells were
considerably larger than those in mice injected with beads alone (Fig. 2, A–C). This was confirmed
by quantitation of the inflammatory mass using an image analyzer (Fig. 2D). The inflammatory mass was similar in mice receiving Th1
cells, Th2 cells, or a mixture of the two phenotypes. However, a
difference was evident from measurement of lung hydroxyproline content
as a marker of fibrosis. Although all of the mice receiving DO11.10
cells showed an increase in hydroxyproline content over controls
receiving beads alone, hydroxyproline content was higher with Th2
cells, or Th2 together with Th1 cells, than with Th1 alone (Fig. 3).
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-actin as a
positive control for the RT-PCR assay, samples were scored as positive
or negative based on the presence or absence of a visible band on gels
stained with ethidium bromide. The results are summarized in Table II. Lungs from mice receiving Th1 cells
were positive for IFN-, a Th1 marker, and predominantly negative for
the Th2 cytokine IL-13. The reverse was true in recipients of Th2
cells. Lungs from mice receiving a mixture of both cell types were
predominantly positive for both cytokines. The intensity of RT-PCR
bands for IFN- and IL-13 in lungs from mice receiving the Th1/Th2
combination was markedly lower than in mice receiving the individual
cell types (Fig. 4). This could be the
result of reciprocal competition between the two cell types
(31) or simply due to transfer of a lower total number of
each cell type in the mixed population. Expression of collagen III
mRNA, an indicator of fibrosis, was seen exclusively in lungs from
the mice that received Th2 cells, either alone or in combination with
Th1 cells. Again, the RT-PCR product was more prominent in the Th2 only
group.
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Influence of Th1 and Th2 cells on infection with M. tuberculosis
Having shown that the DO11.10 T cells retained their phenotype after adoptive transfer and were able to influence responses in the lung, we next investigated the course of M. tuberculosis infection in mice receiving Th1 or Th2 cells. For this, we first constructed recombinant strains of M. tuberculosis expressing either the OVA peptide or a control peptide from influenza virus hemagglutin (HA).3 In each case, an oligonucleotide encoding the appropriate amino acid sequence was inserted within a permissive loop of the M. tuberculosis superoxide dismutase protein and the recombinant construct reintroduced into M. tuberculosis H37Rv using a shuttle vector (27). BALB/c mice were injected i.v. with Th0, Th1-, or Th2-polarized DO11.10 splenocytes together with M. tuberculosis recombinants expressing either OVA or HA. Mice were sacrificed on days 7 and 21, and the lungs were removed for examination.
A similar bacterial load was observed in lungs removed from all six
groups of mice on day 7 after infection. However, a significant
difference was observed on day 21 (Fig. 5). The bacterial load in the lungs of
the mice infected with M. tuberculosis OVA in the presence
of Th2 cells was 10-fold higher than in the Th1 mice. In mice receiving
Th0 cells, the bacterial load was intermediate; closer to that in the
Th2 recipients but significantly different from either of the other two
groups (p = 0.02). In contrast, no difference
was observed between the three groups challenged with an equivalent
dose (1–2 x 106 CFU) of M.
tuberculosis HA. The same trend was observed after challenge with
a higher dose of M. tuberculosis. Again, there was no
difference in bacterial load at day 7, but at day 21, lung counts from
Th2 mice (8.5 ± 2.5 x 107 CFU) were
significantly greater than in Th1 mice (1.7 ± 0.7 x
107 CFU), although only slightly higher than the
Th0 group (7.4 ± 1.8 x 107 CFU).
These results demonstrate that transfer of the Th1 cells enhanced the
ability of the mice to control the mycobacterial infection. The
presence of Th2 cells had a smaller reverse effect. Neither cell
phenotype influenced infection with the HA control strain lacking the
specific antigenic target.
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A). Conversely, the lung
weight was highest in the Th2 group. This was most clearly seen in the
lower dose challenge, during which overall body weight remained
comparable between the groups (Fig. 6B). Hydroxyproline
content was significantly higher in Th2 compared with Th1 lungs
(p = 0.02) (Fig. 6C). No
pathological differences were observed between the three groups
challenged with M. tuberculosis HA.
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. Lungs from the Th0 group were scored
as showing an intermediate level of infiltration. More detailed
examination revealed filling of the alveoli by an infiltrate of
mononuclear inflammatory cells and neutrophils. Although the infiltrate
was more extensive in the Th2 mice, there was no evidence of any
significant qualitative differences in the nature of the lesions among
the different groups. No eosinophilia was observed in any of the lung
sections. Histological examination of liver sections from infected mice
similarly revealed quantitative but not qualitative differences in
granuloma formation.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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, and the
chemokine RANTES (26, 32). Type-2 granulomas resemble
those induced in response to intact eggs from Schistosoma
mansoni (33) and are characterized by Th2 cytokines,
recruitment of eosinophils, and the deposition of collagen
(26). The granulomas formed around OVA-coated beads after
adoptive transfer of Th1- or Th2-polarized DO11.10 cells in the present
study conform to the type-1/type-2 paradigm, with raised levels of
hydroxyproline and collagen III expression in granulomas formed in the
Th2 recipients. Fibrosis in granulomatous lesions is regulated by a
complex network of fibroblasts and lymphocytes. Collagen biosynthesis
is stimulated by Th2 cytokines, such as IL-4 and IL-13, and
reciprocally inhibited by the Th1 cytokines, IFN- and IL-12
(34, 35). The observations with the adoptive transfer
system are consistent with the hypothesis that fibrosis is stimulated
by the direct action of Th2 cytokines, rather than as an indirect
consequence of their effect on Th1 responses. Adoptive transfer of in
vitro polarized T cells provides an additional approach that
complements existing gene knockout and cytokine treatment models for
analysis of the dynamics of granuloma formation
(36, 37, 38, 39, 40).
Infection of the DO11.10 recipient mice with virulent M.
tuberculosis presents a more complex immunological challenge. We
elected to use a relatively high-dose i.v. challenge for these initial
experiments with the aim of ensuring rapid evolution of the infection
in the context of a high circulating level of the adoptively
transferred cells and also of maximizing the opportunity of identifying
alterations in pathology. We used intact BALB/c mice in preference to T
cell-depleted animals as recipients because we wished to analyze the
effect of adding defined T cell phenotypes on top of the complex
natural antimycobacterial response. A striking finding from the study
is that adoptive transfer of Th1 cells resulted in a 10-fold reduction
in mycobacterial multiplication during the first three weeks of the
acute infection. This effect is of a similar magnitude to that obtained
by BCG vaccination or by adoptive transfer of splenocytes from mice
exposed to M. tuberculosis infection (41).
Splenocyte cultures used for adoptive transfer contain cell types in
addition to the OVA-specific DO11.10 T cells. However, the absence of
any influence on infection with M. tuberculosis expressing
the irrelevant HA epitope indicates that the effects observed during
M. tuberculosis OVA challenge are mediated by the
epitope-specific TCR-transgenic cells. A similar level of protection in
the acute i.v. challenge model has previously been described after
adoptive transfer of a clonal CD8+ T cell
population expressing IFN- (42). Some reservations must
be expressed concerning the extent to which these results can be
extrapolated to a more physiological low-dose aerosol challenge
(43), but the fact that this level of protection can be
generated by a T cell population directed toward a single antigenic
determinant is of interest in the context of attempts to develop
subunit vaccines against tuberculosis. Despite the large number of Ags
presented by a mycobacterial pathogen, an appropriate T cell response
to one epitope is sufficient to significantly alter the course of
infection. Further manipulation of the DO11.10 model, for example, by
expression of the OVA determinant on protein carriers expressed in
different subcellular locations (44), may generate data
relevant to rational vaccine design.
The OVA epitope in the challenge strain is carried on a plasmid vector routinely maintained in the mycobacteria by antibiotic selection (27). The absence of antibiotic selection in vivo, in combination with the possible immunological counterselection by Th1 cells, encouraged us to screen for plasmid loss during infection. However, plating of lung homogenates in the presence and absence of hygromycin provided no evidence of measurable plasmid loss in any of the groups at the 21-day time point. Additional experiments monitoring plasmid stability over a longer time course may provide a means of measuring Th1 immune pressure on mycobacterial growth.
The effect of Th2 cell transfer on mycobacterial growth was less marked. The modest increase in bacterial load in Th2 compared with Th0 recipients is consistent with a possible antagonistic effect of Th2 cytokines on development of the natural Th1 response to the infection (31). The weight loss in Th2 mice challenged with the high dose of M. tuberculosis OVA and the increased lung weight suggest some exacerbation in the pathology of the infection. This could be attributed to a direct contribution of Th2 cells to pathology or may simply reflect more advanced disease due to the enhanced mycobacterial growth in these mice. Although lesions were more extensive in the Th2 lungs, there was no evidence of any qualitative change indicative of Th2 modulation of the inflammatory process. Consistent with previous observations in a BCG-induced granuloma model (45), hydroxyproline content was significantly reduced in mice exposed to an augmented Th1 response. Hydroxyproline levels were similar in the Th0 and Th2 recipients.
It will be of considerable interest to extend the DO11.10 model over a more prolonged course of infection. Transfer of Th2 cells subsequent to the initial Th1-dominated phase of the response may have a more marked impact on disease progression, for example, providing an opportunity to examine the contribution of profibrotic events to mycobacterial persistence. The ability to track adoptively transferred T cells using clonotypic Abs may also assist in investigation of the anatomical location of mycobacteria in low-dose persistence models.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Prof. Douglas Young, Department of Infectious Diseases and Microbiology, Imperial College School of Medicine, Saint Mary’s Campus, Norfolk Place, London W2 1PG, U.K.
3 Abbreviation used in this paper: HA, hemagglutin.
Received for publication August 15, 2000. Accepted for publication December 27, 2000.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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gene-disrupted mice. J. Exp. Med. 178:2243. in resistance to Mycobacterium tuberculosis infection. J. Exp. Med. 178:2249.-receptor gene and susceptibility to mycobacterial infection. N. Engl. J. Med. 335:1941. in T-cell-mediated inflammation depends on the Th1/Th2 cytokine balance. Immunology 82:591.[Medline]
T-cell-receptor transgenic system. Proc. Natl. Acad. Sci. USA 89:6065.-transgenic model. J. Exp. Med. 182:1579. from Mycobacterium tuberculosis antigen (PPD)-stimulated lymphocytes. Clin. Exp. Immunol. 94:43.[Medline]
discordantly regulate collagen biosynthesis by functionally distinct lung fibroblast subsets. J. Cell. Physiol. 167:290.[Medline]
and IL-4 knockout mice: analysis of local and regional cytokine and chemokine networks. J. Immunol. 159:3565.[Abstract]
(IFN-). Clin. Exp. Immunol. 119:92.[Medline]This article has been cited by other articles:
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