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*
Genetics Institute, Cambridge, MA 02140; and
Brigham and Womens Hospital, Harvard Medical School, Center for Neurological Diseases, Harvard Medical School, Boston, MA 02115
| Abstract |
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| Introduction |
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A good candidate for regulatory cells that may modulate disease severity and onset are CD4+ Th2 cells. Th2 cytokines can clearly antagonize the function and differentiation of Th1 cells (5, 6), and IL-4 and TGF-ß (7), and IL-10 (8) can be detected in the CNS in animals recovering from EAE. Additionally, neutralization or the absence of the Th2 cytokines IL-4 and IL-10 can result in more severe disease (9, 10, 11, 12). Attempts at regulating disease however with Th2 cells have met with mixed results. Although Th2 clones have been reported to successfully prevent EAE when given at the same time as Ag (13, 14), adoptive transfer of CNS-Ag-specific Th2 cells either at the same time or following transfer with committed encephalitogenic Th1 cells fails to inhibit disease (15, 16) or may only partially eliminate disease (17). A recent study showed that Th2 cells may also induce EAE when transferred into T cell-deficient animals (16).
Induction of Th2 responses concordant with the Th1 response has been shown to successfully suppress EAE. Expression of Th2 cytokines by activated bystander cells, at the induction of disease, will effectively inhibit the Th1 response by immune deviation, where the cytokine profile is shifted from an encephalitogenic Th1 type to Th2 to alter disease severity (18). SJL mice that were preimmunized with keyhole limpet hemocyanin in IFA to generate a memory Th2 population did not develop EAE when challenged with keyhole limpet hemocyanin and encephalitogenic peptide (18). In another system, immunization of mice with LR, an APL of PLP peptide 139-151, protected mice from EAE induced with PLP peptide as well as unrelated encephalitogenic peptides. The T cell population that is induced by LR is of a Th2/Th0 phenotype, cross-reacts with PLP 139-151, and can down-regulate actively induced EAE through bystander effects (19, 20).
We have used an adoptive transfer model of EAE to examine the potential contributions of Th2 cytokines in the regulation of Th1-mediated disease. We show here for the first time that a Th2 cell responding to an APL can regulate EAE mediated by an encephalitogenic Th1 population. In these experiments, primed encephalitogenic lines are used to transfer disease after coincubation with a Th2 clone specific for LR. We have systematically examined the effects of Th2 cytokines, individually and in combinations, from this clone for their effects on disease. Our data indicate that particular combinations of Th2 cytokines are most effective at modulating disease. Interestingly, IL-4 and IL-13 were synergistic in suppression of disease, suggesting that effects mediated through the IL-4 receptor on T cells are complemented by effects on other cell types expressing the IL-4/IL-13 receptor.
| Materials and Methods |
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Adoptive transfer cocultures and 1F1 cells were activated in
proliferation medium: DMEM with 10% FBS, 2 mM glutamine, 1000 U/ml
penicillin-streptomycin (Life Technologies, Gaithersburg, MD), 50
µg/ml gentamicin (Life Technologies), 600 µg/ml anti-PPLO agent
(Life Technologies), and 5 x 10-5 M 2-ME,
0.1 mM nonessential amino acids (Life Technologies), and 1 mM sodium
pyruvate. After restimulation, 1F1 cells were maintained in the above
medium with the following added (clone medium): 1x MEM essential
vitamins (all from Life Technologies), 0.2 mM arginine, 0.1 mM
asparagine, 0.1 mg/ml folic acid, and 1% human T-Stim without PHA
(Collaborative Biomedical Products, Bedford, MA). ELISAs for IL-2,
IL-4, IL-5, IL-6, and IL-10 were done with pairs of Abs purchased from
PharMingen (San Diego, CA). Assays for the following cytokines used
commercial kits: IL-13, IL-17, and GM-CSF (R&D Systems, Minneapolis,
MN), TNF-
(Genzyme, Boston, MA), and TGF-ß (Promega, Madison, WI).
Neutralizing Abs for adoptive transfer experiments were purchased from
the following sources: IL-4 (catalogue no. 18190D; PharMingen), IL-10
(catalogue no. 1996-01; Genzyme), and TGF-ß (catalogue no. AB-101NA;
R&D Systems). IL-13 was neutralized with a human Fc fusion protein of
the extracellular domain of the high-affinity murine IL-13
2 receptor
(A25Fc) (21) made at Genetics Institute (Cambridge, MA).
PLP139-151 wild-type (HSLGKWLGHPDKF) and LR (HSLGKLLGRPDKF)
peptides were synthesized, purified and characterized at the Genetics
Institute. SJL/J mice were purchased from The Jackson Laboratory (Bar
Harbor, ME). Cytokines were obtained from the following sources:
Genzyme, murine (m) IL-4 (MIL-4-C); mIL-5 (MIL-5); mIL-9 (80-2809-00);
mIL-10 (2488-01); mGM-CSF (RM-CSF-C); and mTNF-
(TNF-M); and R&D
Systems, mIL-13 (413-ML); human TGF-ß1 (240-B).
Cell lines and clones
The LR 1F1 T cell clone was generated from lymph node cells from LR and PLP-immunized mice as described (20) and is maintained in clone medium. It does not cross-react with PLP139-151 (20). 1F1 cells are restimulated every 3 wk in proliferation medium with 10 µM LR peptide and 10:1 irradiated (3000 rads) male SJL spleen cells.
1F1 conditioned medium
Supernatants were harvested from 1F1 cells cultured at 106 cells/ml with 107 irradiated spleen cells and 10 µM LR peptide after 72 h and tested in ELISAs. Control conditioned media were generated from cultures containing no LR peptide (nonactivated 1F1) and no 1F1 cells (peptide pulsed spleen cells).
DNA chip analysis
One microgram of 1F1 cytoplasmic RNA was extracted from 4- and 16-h anti-TCR-stimulated cells (1 µg H57-597 PharMingen 01300D/ml coated tissue culture dishes). 1F1 cells (107/ml) and poly(A+) RNA were isolated, amplified, and converted to cDNA and then to biotin-labeled RNA in an in vitro transcription reaction as described by Lockhart et al. (22). Samples were hybridized to 114 gene arrays (Affymetrix, Santa Clara, CA) in a self-contained flow cell and imaged with a scanning confocal microscope also as described (22). Data are expressed as the relative message frequency per 106.
Adoptive transfer of EAE
Spleen cells from female SJL mice immunized for 810 days with 100 µg PLP139-151 in CFA injected s.c. were harvested and cultured at 3 x 106 cells/ml with 10 µM PLP in proliferation medium (PLP-spleen). A total of 20 U/ml recombinant COS human IL-2 was added on day 2 of culture. Cultures were harvested after 3 days and washed, and 5 x 1061 x 107 cells were injected i.p. into naive 812-wk-old SJL females. Some experiments were designed to test the effect of including 1F1 Th2 cells in the culture. 1F1/PLP-spleen cell cocultures typically included 3 x 105 resting 1F1 cells/ml and 10 µM LR peptide added at the same time as the PLP-spleen cells. To neutralize Th2 cytokines in 1F1 cocultures, 10 µg/ml of the indicated neutralizing Ab was added at the start of culture. A25Fc (21) at 2 µg/ml was included in some cultures to neutralize IL13. Control cultures without 1F1 cells contained PLP-spleen cells with PLP peptide and the indicated Ab. Culture supernatants from PLP-spleen cultures and 1F1 cocultures were harvested after 3 days before adoptive transfer to measure cytokines. Mice were scored for EAE using the following scale: 1, limp tail; 2, unsteady gait; 3, hind limb paralysis; 4, hind and forelimb paralysis; and 5, death.
| Results |
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Typically, immunization of SJL mice with the CNS peptide PLP139-151 in CFA results in an inflammatory and demyelinating disease characterized by ascending paralysis and CNS mononuclear cell infiltrates (23, 24, 25). Adoptive transfer of lymph node or splenic T cells derived from mice primed with PLP139-151 also results in induction of disease in naive mice. Previous work has shown that coimmunization of mice with PLP139-151 and LR peptide, an altered peptide derived from PLP139-151 in which the TCR contact residues Trp144 and His147 are changed to Leu144 and Arg147, results in disease suppression (20). These results suggested that T cells primed by immunization with the LR peptide act to regulate disease.
LR 1F1 (1F1) is a T cell clone derived from SJL mice immunized with the
LR peptide (20). To determine whether this T cell clone
could regulate disease induced by primed encephalitogenic T cells, we
compared the encephalitogenic potential of T cell populations from mice
immunized with PLP139-151 with similar populations
cocultured and coactivated with 1F1 T cells. Immune spleen cells from
mice immunized 810 days earlier with PLP139-151
were cocultured for 3 days with resting 1F1 T cells and the appropriate
peptides. After 3 days, cells from cocultures were adoptively
transferred into naive SJL mice, and the mice were monitored for
disease. As shown in Fig. 1
, mice that
received cells from cultures containing only PLP139-151 immune
spleen cells activated with their corresponding peptide
(PLP-spleen/PLP) developed EAE, whereas cultures containing both
PLP-spleen cells and 10% 1F1 cells with their corresponding peptides
(PLP-spleen/PLP + 1F1/LR) did not transfer disease. LR peptide itself
was unable to affect the disease transferred by PLP-spleen cells since
cells from cultures containing both PLP and LR peptides transferred
disease as well as PLP-stimulated spleen cells alone. Additionally
PLP-spleen/PLP cultures that included 10% 1F1 cells without the LR
peptide also transferred EAE, suggesting that the 1F1 cells required
activation with APL to suppress transfer of disease by PLP-spleen
cells. Transfer of 1F1 cells activated with normal spleen cells and LR
peptide did not result in EAE.
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We examined the levels of Th1 and Th2 cytokines in the conditioned
medium from cocultures containing increasing concentrations of 1F1
cells. Cells from these activated cocultures were then transferred to
naive mice to evaluate their potential to transfer disease. As shown in
Table I
, cultures containing as few as
2% 1F1 cells with the PLP-spleen cells transferred less severe EAE
than the PLP-spleen cells alone. Disease transfer from cocultures
containing 20% 1F1 cells was completely inhibited. Cytokine analysis
of coculture supernatant revealed 5-fold lower levels of the Th1
cytokines IL-2 and IFN-
, and increasing levels of Th2 cytokines in
proportion to the number of 1F1 cells included in the culture.
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1F1 cells secrete high levels of Th2 cytokines upon activation
To identify candidate proteins made by 1F1 cells that might
regulate EAE, we used oligonucleotide arrays to examine the expression
of 114 different genes known to be expressed in T cells, including
cytokine- and lymphocyte-specific genes. RNA was isolated from resting
1F1 cells and from 1F1 cells that had been activated for 4 and 16
h with plate-bound anti-TCR Ab. The RNA was amplified, labeled, and
hybridized to the oligonucleotide array as described above (see
Materials and Methods). Message levels for 27 cytokines and
6 chemokines were examined. As depicted in Fig. 2
, mRNA levels for several cytokines were
significantly up-regulated, 3-fold or greater, compared with
t = 0 at the 4-h time point. The mRNA for several genes
of interest was increased from one to two copies per 106
messages at t = 0 to several hundred copies per
106 messages at 4 h: IL-4, 906; IL-10, 608; IL-13, 1944;
and GM-CSF, 846. TGF-ß was increased 8-fold from 52 to 401 copies per
106 messages. Expression of
macrophage-inflammatory protein1
and macrophage-inflammatory
protein1ß was also induced by activation. We also examined the
expression of genes encoding 28 cytokine receptors and 42 lymphocyte
cell surface proteins or adhesion molecules. Message levels for the
cell surface receptors IL-2R
, ß, and
, TCR-ß, 4-1BB, and
4-1BBL were also increased upon activation. P-selection glycoprotein
ligand-1 expression was rapidly down-modulated after activation.
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To examine the role of Th2 cytokines in the modulation of the
adoptive transfer model of EAE by 1F1 cells, neutralizing Abs or
reagents to IL-4, IL-10, or IL-13 were included in the 1F1/PLP-spleen
cocultures as indicated in Fig. 4
. ELISA
(data not shown) confirmed neutralization of each cytokine in the
coculture supernatant. Neutralization of either IL-4 or IL-13 alone
only partially abrogated the protective effect of the 1F1 cells. In
each case, the disease observed was less severe than that of the
activated spleen-PLP controls, suggesting that other factors made by
1F1 could also contribute to the suppression of EAE. Anti-IL-10 did not
neutralize any of the protective effects of 1F1 cells and,
interestingly, anti-IL-10 in combination with anti-IL-4
appeared to counteract the previously observed neutralization effect of
anti-IL-4 alone. Animals transferred with PLP-spleen/1F1/LR
cocultures containing combinations of anti-IL-4, anti-IL-10,
and anti-IL-13 or anti-IL-4 and anti-IL-13 had
significantly more disease than mice receiving untreated cocultures.
Cultures containing all three Abs however transferred slightly less
disease (less severity and delayed onset) compared with PLP-spleen
control cultures not containing 1F1 cells, suggesting that not all
down-regulatory effects had been neutralized. Interestingly, inclusion
of all three Abs in control PLP-spleen/PLP cultures resulted in the
transfer of significantly less disease (Fig. 4
, bottom left
panel) when compared with PLP-spleen/PLP cultures with no Abs.
These results suggested that the combination of these three cytokines
participate in the maximal EAE response transferred by the
PLP-spleen/PLP cultures alone.
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TGF-ß was detected both in activated 1F1 supernatants (670
pg/ml) and at low levels of mRNA by DNA chip analysis. As shown in Fig. 5
, addition of anti-TGF-ß to
PLP-spleen-1F1 cocultures partially neutralized the protective effect
of 1F1, suggesting that TGF-ß plays a role in suppressing transfer of
EAE by coculture with the 1F1 cells. Since neutralization of IL-13
alone (Fig. 4
) removed a significant amount of 1F1 suppression, we
tested whether the combination of anti-IL-13 and anti-TGF-ß
would be additive. Interestingly, neutralization of the combination of
IL-13 and TGF-ß was no more effective than neutralization of either
cytokine alone. This effect was also observed with the combination of
anti-IL-4 and anti-TGF-ß (data not shown). Neutralization of
the four cytokines (IL-4, IL-13, IL-10, and TGF-ß) however not only
abrogated the protective effect of the 1F1 cells but actually
exacerbated disease severity when compared with PLP-spleen cells
cultured without 1F1 cells.
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To determine whether individual Th2 cytokines suppress
adoptive transfer of EAE, each cytokine was added separately to
cultures of PLP-spleen cells at the approximate concentrations that
were measured in cultures containing activated 1F1 cells that did not
transfer disease. As shown in Fig. 6
,
both IL-4 (25 ng/ml) and TGF-ß alone were able to significantly
inhibit EAE, whereas IL-13 (100 ng/ml) was only partially inhibitory.
Addition of IL-9 (10 ng/ml) or IL-10 (50 ng/ml) did not significantly
affect the disease course whereas GM-CSF appeared to slightly enhance
the severity of EAE. Fig. 7
shows that
the combination of a suboptimal dose of IL-4 (5 ng/ml) with either
IL-10 or IL-13 was synergistic in suppressing disease and was as
effective as the combination including the four cytokines IL-4, IL-10,
IL-13, and TGF-ß. Levels of the cytokines IL-2, IL-3, IL-4, IL-10,
IL-17, GM-CSF, IFN-
, and TNF-
from supernatants of
cytokine-treated cultures were measured by ELISA and compared with
PLP-spleen/PLP control cultures. Table II
shows each measured cytokine expressed as a percentage of the control
culture. The single cytokines which had the greatest effect in
modulating transfer of disease, 1.0 ng/ml TGF-ß, 25 ng/ml IL-4, 300
ng/ml IL-13, and IL-4 plus IL-13, also contained significantly lower
levels of IFN-
compared with control PLP-spleen cultures. Cells from
these cultures also transferred significantly less disease (Figs. 6
and 7
). IL-4 and IL-10 were present at low levels in some cultures, but
none of the cytokine treatments significantly altered these levels from
controls (data not shown). TGF-ß suppressed the levels of all
measured cytokines with the exception of IL-17, whereas IL-4-treated
cultures had increased levels of IL-2, IL-3, GM-CSF, and TNF-
and
decreased levels of IL-17. Although the combination of IL-4 and IL-13
was more effective in suppressing transfer of disease than IL-13 alone,
both cultures showed reduced levels of IFN-
but only the IL-4 and
IL-13 combination showed reduced levels of IL-17.
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| Discussion |
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We have used an adoptive transfer model of EAE induced with PLP139-151 in the SJL mouse to examine the potential role of Th2 cells and cytokines in modulating the disease induced by PLP-primed T cells. We demonstrated that coculture of a Th2 cell line, 1F1, with PLP-primed encephalitogenic Th1 cells prevented adoptive transfer of EAE. Disease prevention was dependent upon activation of the Th2 cells, since cocultures containing 1F1 cells without the activating LR peptide transferred EAE. The inhibition by the 1F1 cells was due to soluble bystander effects since the 1F1 cells only responded to a non-cross-reactive analogue peptide included in the culture and were still inhibitory if activated on separate sides of a transwell membrane (data not shown).
We went on to define the mechanism by which the 1F1 cells mediate disease suppression and have systematically examined the role of cytokines produced by these cells. Both gene chip analysis and ELISA identified potential immunoregulatory cytokines expressed and secreted by the 1F1 cells. By neutralizing and add-back experiments, our results showed that several Th2 cytokines made by 1F1 cells were capable of suppressing the adoptive transfer of EAE. We found that IL-4, IL-13, and TGF-ß were critical for the observed down-modulation of disease by 1F1 Th2 cells.
We found that IL-10 alone did not play a major role in down-regulating the induction of disease by adoptive transfer. The described role for IL-10 in the regulation of EAE is complex, having both exacerbating and protective functions depending on the timing of IL-10 administration and, most likely, the types of other cytokines that are present. IL-10 has potent down-regulatory effects during the priming and induction phases of the response to autoantigen (26, 27, 28) as well as in the recovery phase. If administered at the same time as PLP, IL-10 delayed disease onset and severity (27). Mice transgenic for IL-10 were resistant to the induction of EAE (9), suggesting that encephalitogenic cells do not develop in the presence of IL-10. In later stages of disease, IL-10 mRNA expression is increased during the recovery phase (8, 10) and IL-10-deficient mice develop a more chronic disease following immunization with myelin oligodendrocyte glycoprotein (9, 29), both suggesting that IL-10 is required for recovery from EAE. In adoptive transfer models however IL-10 is ineffective in inhibiting disease. IL-10 pretreatment of lymph node cells sensitized to MBP before adoptive transfer had no effect on their ability to transfer disease (12). Similarly, treatment of mice with IL-10 at various intervals after adoptive transfer showed no or a worsening effect on clinical signs of EAE. These results suggest that IL-10 alone has little or no effect on primed Th1 cells or established disease. As shown by the experiments described in this report, addition of as much as 50 ng/ml IL-10 had little or no effect on disease transferred by activated T cells. We have also been unable to inhibit proliferation of PLP-spleen cells to PLP peptide in vitro (data not shown).
Neutralization of IL-10 in the 1F1 cocultures suggested that this cytokine alone does not play a significant role in suppressing disease and that additional cytokines from 1F1 are involved in mediating suppression. Moreover, 1F1 cocultures with IL-10 present (treated with anti-IL-4 and anti IL-13) transferred more severe disease than cultures without IL-10, implying an enhancing role for IL-10. Removal of only IL-4 and IL-10 from the cocultures (leaving IL-13 and TGF-ß) was ineffective in abrogating suppression whereas removal of IL-4 alone (leaving IL-10, IL-13, and TGF-ß) resulted in disease, again suggesting that IL-10 contributes to enhanced encephalitogenicity. In control PLP-spleen cultures as well, neutralization of IL-10 alone resulted in less severe disease and neutralization of the combination of IL-10, IL-4, and IL-13 resulted in significantly less disease, suggesting that IL-10 in combination with other cytokines could enhance encephalitogenicity. These results from the experiments with Abs to IL-10 suggest that the suppressive effects of IL-4 and IL-13 in 1F1 cocultures are more profound in the absence of IL-10. The direct cytokine add-back experiments demonstrate that IL-10 alone neither suppresses disease transfer nor significantly enhances EAE when included at the 10-ng/ml level, but can suppress disease when included with a low level of IL-4. The effect of IL-10 appears to be complex and may enhance or suppress Th1 effector function depending upon the nature of the cytokine milieu.
In contrast to IL-10, we observed that activation of PLP-specific
spleen cells in the presence of IL-4 inhibited adoptive transfer of EAE
(Fig. 6
). These data are in agreement with studies in the MBP-induced
model of EAE, where Racke et al. (11) have shown that
administration of IL-4 after adoptive transfer of MBP-specific lymph
node cells limited the severity of disease. Similarly in the MBP model,
targeted delivery of IL-4 by retrovirally transduced encephalitogenic T
cell hybridomas 10 days after immunization resulted in reduced onset
and severity of disease (30). IL-4 plays a less
significant role in regulating the induction of EAE and in recovery
from actively induced EAE. IL-4-transgenic mice develop slightly more
severe EAE with similar recovery times compared with nontransgenic
littermates, and IL-4-deficient mice do not develop more severe EAE
when compared with wild-type controls (9, 10).
IL-4 was particularly effective in inhibition of adoptive transfer of
EAE in combination with other Th2 cytokines. We observed that IL-4
synergized with IL-10 to inhibit adoptive transfer of EAE in
experiments using suboptimal concentrations of IL-4, even though IL-10
alone had no effect on disease severity. Surprisingly, neutralization
of IL-10 and IL-4 in the 1F1 cocultures had no effect on disease
severity, although neutralization of IL-4 alone partially abrogated the
suppressive effects of the 1F1 cells. Interference between the
suppressive effects mediated by IL-4 and IL-10 was also seen in the
direct disease model by Nagelkerken et al. (27). In this
experiment IL-4 had no effect on the severity of EAE when injected at
the same time as PLP peptide in SJL mice, but abrogated the inhibitory
effects of IL-10 when administered with IL-10. In our hands, IL-4,
unlike IL-13 or TGF-ß alone, also significantly reduced the levels of
IL-17 when compared with control PLP-spleen cultures. IL-17 has
recently been reported to stimulate the production of IL-1 and TNF-
from macrophages, suggesting a role for IL-17 in promoting an
inflammatory response (31).
We found that murine IL-13 can inhibit the adoptive transfer of EAE in PLP-induced disease in SJL mice. Additionally, neutralization of IL-13 in the 1F1-spleen cell cocultures demonstrated a role for IL-13 in suppressing disease transfer. In agreement with our data, expression of human IL-13 by a hybridoma cell line adoptively transferred into rats results in suppression of clinical signs of EAE induced by immunization with MBP-CFA (32). The results in the report show that IL-13 synergized with IL-4 to inhibit adoptive transfer of EAE, although both IL-4 and IL-13 were able to independently inhibit adoptive transfer of EAE at high concentrations.
The mechanism for suppression by IL-13 is not clear, although it is likely to be functioning through APC in the coculture. IL-13 has been reported to exert both pro- and anti-inflammatory effects on monocytes. IL-13 up-regulates the capacity of monocytes to present Ag, resulting in increased proliferation of T cells to Ag (33). IL-13 can have a priming immunostimulatory effect on monocytes if added before an inflammatory stimulus and suppressive effect when added after (34). In our hands, proliferation of PLP-specific lymph node or spleen populations in the presence of PLP peptide over a wide range of IL-13 concentrations was not inhibited and was enhanced at higher concentrations of IL-13 (data not shown).
IL-4 and IL-13 use a shared receptor on monocytes and other APC
(35). Both IL-4 and IL-13 can antagonize the effects of
IFN-
and down-regulate inflammatory cytokines (33). We
observed decreased levels of IFN-
in cocultures containing 1F1 cells
and in PLP-spleen cultures containing the combination of IL-4, IL-13,
and IL-10, suggesting that IFN-
made by the Th1 population was
down-regulated in these cultures. Both IL-13 alone and IL-4 alone also
decreased IFN-
levels in these studies. In contrast, we observed
increased levels of TNF-
in PLP-spleen activation cultures
containing IL-13 alone or IL-4 and IL-13 in combination.
IL-4 exhibits comparable anti-inflammatory effects to IL-13, but IL-4 and IL-13 do not exhibit synergistic effects on monocytes (33). IL-4 unlike IL-13 can enhance proliferation of activated T cells (33), and the synergy we observe between IL-13 and IL-4 may be due to the actions of IL-13 and IL-4 on distinct APC and T cell populations, respectively.
As with IL-13, TGF-ß can have both proinflammatory and anti-inflammatory effects, depending on concentration, the presence of other cytokines, and activation status of the T cell (36). Neutralization of TGF-ß in the 1F1/PLP-spleen cocultures showed that this cytokine contributed significantly to the inhibition of EAE by 1F1 cells. Addition of as little as 100 pg/ml of TGF-ß to the culture before adoptive transfer also inhibited development of EAE. Of all of the cytokines made by the 1F1 cells, we found that only TGF-ß also inhibits the proliferation of PLP-specific LNC or spleen cell populations in vitro (data not shown). Previous reports have described the in vivo inhibitory role of TGF-ß in EAE (37, 38, 39, 40) and have shown that addition of anti-TGF-ß exacerbates EAE, suggesting a regulatory role for endogenous TGF-ß (41, 42). We found that addition of low levels of TGF-ß alone inhibited adoptive transfer of EAE by PLP-spleen cells and suppressed levels of Th1 cytokines in the culture supernatant. Two additional experiments supported inhibitory roles for TGF-ß in our adoptive transfer model of EAE. Neutralization of TGF-ß in cocultures of 1F1 cells with PLP-spleen restored disease transfer and addition of anti-TGF-ß in combination with Abs to IL-4, IL-10, and IL-13 would sometimes increase disease severity, supporting the concept that TGF-ß was itself an endogenous regulator of the Th1 population. TGF-ß in combination with IL-4, IL-10, and IL-13 showed the most profound inhibitory effect on both the transfer of EAE and the production of Th1 cytokines in the culture supernatant, suggesting that the presence of additional Th2 cytokines are important for a maximum inhibitory effect.
Other 1F1 cytokines evaluated in this adoptive transfer model were IL-5, IL-9, and GM-CSF. Not unexpectedly, IL-5, with reported activities on eosinophils and B cells, and IL-9, with activities on mast cells and some T cells (43, 44), were found to have negligible effects on the adoptive transfer of EAE in this report. Preliminary results with weakly encephalitogenic PLP-spleen populations however suggest that IL-9 may have a subtle inhibitory effect on adoptive transfer of EAE. We have found that IL-9 enhances proliferation of activated T cell populations, and it is formally possible that the IL-9 treatment allows one to transfer lower numbers of encephalitogenic T cells for disease induction. GM-CSF on the other hand enhances Ag presentation and secretion of inflammatory cytokines in macrophages (45). In this report, addition of a low level of GM-CSF to PLP-spleen cultures had no effect whereas inclusion of higher levels led to a marginal enhancing effect in the adoptive transfer of EAE.
Other cytokines made by 1F1 cells such as IL-6 and IL-3, not evaluated in adoptive transfer experiments presented in this report, have been implicated to play a role in encephalitogenicity. EAE cannot be induced in IL-6-deficient mice (46, 47) nor can IL-6-deficient myelin oligodendrocyte glycoprotein-specific T cells transfer disease, suggesting that IL-6 is essential for the development of disease (46). IL-3 has also been reported to enhance the growth of encephalitogenic T cells (48), and we have found that IL-3 enhances the proliferation of Th1 cells as well (data not shown).
In summary, our results indicate that the most effective means of modulating EAE by immune deviation results from the induction of certain combinations of Th2 cytokines, which can modulate EAE induced by the adoptive transfer of primed, encephalitogenic T cells. The most effective combinations included TGF-ß, IL-4, and IL-13. This combination of cytokines is similar to that observed in the previously described Th3 subset of regulatory cells (13) and is predicted to have effects on both the APC and T cell populations. Our data support the idea that induction of specific combinations of Th2/Th3 cytokines could be of potential therapeutic benefit, in that suppression of disease mediated by primed, encephalitogenic T cells was observed. Our data also suggest that the variation in results obtained in other studies addressing the role of Th2 cells in modulating EAE may be due to differences in the precise cytokine profiles expressed by these various populations.
| Acknowledgments |
|---|
| Footnotes |
|---|
2 Abbreviations used in this paper: EAE, experimental autoimmune encephalomyelitis; PLP, proteolipid protein; APL, altered peptide ligand; MBP, myelin basic protein; LR, altered peptide ligand of PLP139-151; A25Fc, IL-13 receptor
extracellular fusion protein; m, murine. ![]()
Received for publication November 2, 1999. Accepted for publication January 26, 2000.
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J. Ochoa-Reparaz, A. Rynda, M. A. Ascon, X. Yang, I. Kochetkova, C. Riccardi, G. Callis, T. Trunkle, and D. W. Pascual IL-13 Production by Regulatory T Cells Protects against Experimental Autoimmune Encephalomyelitis Independently of Autoantigen J. Immunol., July 15, 2008; 181(2): 954 - 968. [Abstract] [Full Text] [PDF] |
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D. L. Smith-Bouvier, A. A. Divekar, M. Sasidhar, S. Du, S. K. Tiwari-Woodruff, J. K. King, A. P. Arnold, R. R. Singh, and R. R. Voskuhl A role for sex chromosome complement in the female bias in autoimmune disease J. Exp. Med., May 12, 2008; 205(5): 1099 - 1108. [Abstract] [Full Text] [PDF] |
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S. Sinha, L. J. Kaler, T. M. Proctor, C. Teuscher, A. A. Vandenbark, and H. Offner IL-13-Mediated Gender Difference in Susceptibility to Autoimmune Encephalomyelitis J. Immunol., February 15, 2008; 180(4): 2679 - 2685. [Abstract] [Full Text] [PDF] |
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M. D. Mannie and D. J. Abbott A Fusion Protein Consisting of IL-16 and the Encephalitogenic Peptide of Myelin Basic Protein Constitutes an Antigen-Specific Tolerogenic Vaccine That Inhibits Experimental Autoimmune Encephalomyelitis J. Immunol., August 1, 2007; 179(3): 1458 - 1465. [Abstract] [Full Text] [PDF] |
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J. Ochoa-Reparaz, C. Riccardi, A. Rynda, S. Jun, G. Callis, and D. W. Pascual Regulatory T Cell Vaccination without Autoantigen Protects against Experimental Autoimmune Encephalomyelitis J. Immunol., February 1, 2007; 178(3): 1791 - 1799. [Abstract] [Full Text] [PDF] |
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M. A. Kleinschek, A. M. Owyang, B. Joyce-Shaikh, C. L. Langrish, Y. Chen, D. M. Gorman, W. M. Blumenschein, T. McClanahan, F. Brombacher, S. D. Hurst, et al. IL-25 regulates Th17 function in autoimmune inflammation J. Exp. Med., January 22, 2007; 204(1): 161 - 170. [Abstract] [Full Text] [PDF] |
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N. Gao, P. Schwartzberg, J. A. Wilder, B. R. Blazar, and D. Yuan B Cell Induction of IL-13 Expression in NK Cells: Role of CD244 and SLAM-Associated Protein. J. Immunol., March 1, 2006; 176(5): 2758 - 2764. [Abstract] [Full Text] [PDF] |
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W. Zang, S. Kalache, M. Lin, B. Schroppel, and B. Murphy MHC Class II-Mediated Apoptosis by a Nonpolymorphic MHC Class II Peptide Proceeds by Activation of Protein Kinase C J. Am. Soc. Nephrol., December 1, 2005; 16(12): 3661 - 3668. [Abstract] [Full Text] [PDF] |
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S. Jun, W. Gilmore, G. Callis, A. Rynda, A. Haddad, and D. W. Pascual A Live Diarrheal Vaccine Imprints a Th2 Cell Bias and Acts as an Anti-Inflammatory Vaccine J. Immunol., November 15, 2005; 175(10): 6733 - 6740. [Abstract] [Full Text] [PDF] |
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H. Offner, S. Subramanian, C. Wang, M. Afentoulis, A. A. Vandenbark, J. Huan, and G. G. Burrows Treatment of Passive Experimental Autoimmune Encephalomyelitis in SJL Mice with a Recombinant TCR Ligand Induces IL-13 and Prevents Axonal Injury J. Immunol., September 15, 2005; 175(6): 4103 - 4111. [Abstract] [Full Text] [PDF] |
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J. T. Lin, S. L. Martin, L. Xia, and J. D. Gorham TGF-{beta}1 Uses Distinct Mechanisms to Inhibit IFN-{gamma} Expression in CD4+ T Cells at Priming and at Recall: Differential Involvement of Stat4 and T-bet J. Immunol., May 15, 2005; 174(10): 5950 - 5958. [Abstract] [Full Text] [PDF] |
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N. Nath, S. Giri, R. Prasad, A. K. Singh, and I. Singh Potential Targets of 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Inhibitor for Multiple Sclerosis Therapy J. Immunol., January 15, 2004; 172(2): 1273 - 1286. [Abstract] [Full Text] [PDF] |
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A. Teige, I. Teige, S. Lavasani, R. Bockermann, E. Mondoc, R. Holmdahl, and S. Issazadeh-Navikas CD1-Dependent Regulation of Chronic Central Nervous System Inflammation in Experimental Autoimmune Encephalomyelitis J. Immunol., January 1, 2004; 172(1): 186 - 194. [Abstract] [Full Text] [PDF] |
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B. S. Prabhakar, R. S. Bahn, and T. J. Smith Current Perspective on the Pathogenesis of Graves' Disease and Ophthalmopathy Endocr. Rev., December 1, 2003; 24(6): 802 - 835. [Abstract] [Full Text] [PDF] |
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M Bradl and R Hohlfeld Molecular pathogenesis of neuroinflammation J. Neurol. Neurosurg. Psychiatry, October 1, 2003; 74(10): 1364 - 1370. [Abstract] [Full Text] [PDF] |
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B. Murphy, J. Yu, Q. Jiao, M. Lin, T. Chitnis, and M. H. Sayegh A Novel Mechanism for the Immunomodulatory Functions of Class II MHC-Derived Peptides J. Am. Soc. Nephrol., April 1, 2003; 14(4): 1053 - 1065. [Abstract] [Full Text] [PDF] |
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D. G. Alleva, A. Gaur, L. Jin, D. Wegmann, P. A. Gottlieb, A. Pahuja, E. B. Johnson, T. Motheral, A. Putnam, P. D. Crowe, et al. Immunological Characterization and Therapeutic Activity of an Altered-Peptide Ligand, NBI-6024, Based on the Immunodominant Type 1 Diabetes Autoantigen Insulin B-Chain (9-23) Peptide Diabetes, July 1, 2002; 51(7): 2126 - 2134. [Abstract] [Full Text] [PDF] |
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H. H. Hofstetter, C. L. Shive, and T. G. Forsthuber Pertussis Toxin Modulates the Immune Response to Neuroantigens Injected in Incomplete Freund's Adjuvant: Induction of Th1 Cells and Experimental Autoimmune Encephalomyelitis in the Presence of High Frequencies of Th2 Cells J. Immunol., July 1, 2002; 169(1): 117 - 125. [Abstract] [Full Text] [PDF] |
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