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Division of Gastroenterology-Hepatology, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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response in murine schistosomiasis.
SP enhances, while SOM decreases, IFN- secretion. Various
inflammatory mediators induce macrophages to make SOM, but no known
factor limits this expression. It was discovered that SP regulates SOM
synthesis. Splenocytes from normal, uninfected mice cultured with LPS,
IFN-, or IL-10 for 4 h strongly expressed SOM mRNA, but failed
to do so in the presence of SP. The inhibition with 10-9 M
SP was >85% shown by quantitative PCR. Also, splenocyte SOM content
decreased from 1048 ± 275 to <10 pg/4 x 108
cells following SP exposure. Immunohistochemistry identified SOM solely
within splenic macrophages following cytokine stimulation. Mice
infected with Schistosoma mansoni form granulomas in the
liver and intestines resulting from deposition of parasite eggs in
these organs. The granulomas contain macrophages that make SOM
constitutively. SP at 10-8 M decreased SOM mRNA expression
>90% in dispersed granuloma cells cultured for 4 h or longer.
Specific SP receptor antagonists blocked SP suppression of SOM
expression in splenocytes and dispersed granuloma cells, showing that
an authentic SP receptor mediated the regulation. Additional studies
revealed that IL-4 antagonized the SP effect in the spleen. It is
concluded that in granulomas and splenocytes from mice with
schistosomiasis and in splenocytes from uninfected animals that 1) SP
inhibits macrophage SOM induction and ongoing expression at the mRNA
and protein levels acting through the SP receptor, and 2) IL-4 can
antagonizes this SP effect. |
Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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is an important Th1 cytokine that enhances the cellular immune response
to intracytoplasmic pathogens. Substance P
(SP)3 and somatostatin (SOM)
are short polypeptides present at mucosal surfaces and at other sites
of chronic inflammation. In murine schistosomiasis, ova induce
granulomas in the liver and intestines. Both SP and SOM are involved in
the modulation of T cell IFN- secretion in murine schistosomiasis.
SP enhances, while somatostatin decreases IFN- responses (1, 2).
This regulation is significant, because they also modulated IgG2a
production, which is IFN--dependent (3). Also, specific SP (NK1) and
SOM (SSTR2) receptors, which are expressed on T cells (4, 5), mediate
the effects of SP and SOM on IFN- secretion (6). It is likely that
other granuloma inflammatory cell types also express these receptors.
Thus, there is a SP/SOM immunoregulatory circuit in schistosomiasis
that may help modulate the balance between the Th1 and Th2 response.
We recently showed that various lymphoid organs express
preprosomatostatin (ppSOM) mRNA and that macrophages, induced by
various inflammatory mediators such as IFN-, IL-10, TNF-
,
PGE2, cAMP analogues, and LPS, make large amounts of SOM
(7). The goal of this study was to determine whether there also are
regulatory factors that can limit macrophage SOM expression. Because SP
and SOM have opposing immunoregulatory functions, it was ascertained if
SP could alter ppSOM mRNA expression in immunocytes.
It was shown that SP, at physiologic concentrations and operating through the authentic SP receptor (NK1), inhibits macrophage SOM mRNA and peptide expression both in normal splenocytes from uninfected mice and in granuloma cells from schistosome-infected animals. Also, IL-4 can block this SP effect. These data further suggest that SP and SOM are important opposing immunoregulatory molecules that help differentiate Th1 and Th2 responses.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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This study used female CBA mice bought from the National Cancer Institute (Washington, DC). Also used were C57BL/6 IL-4-/- and littermate controls (IL-4+/+), and C57/B129 Rag-1 T and B cell-deficient mice (8). Breeding colonies for the various C57BL/6 and C57/B129 Rag-1 mice were maintained at the University of Iowa. At 7–8 wk of age, some mice were infected s.c. with 50 cercariae of the Puerto Rican strain of Schistosoma mansoni (9, 10).
Dispersal of granuloma cells and splenocytes and cell culture
Livers of mice sacrificed during the 8 wk of infection were homogenized for 30 s at low speed in a Waring blender. Granulomas were collected by 1 x g sedimentation and washed three times in RPMI 1640 medium (hereafter referred to as RPMI). To prepare a single cell suspension from these granulomas, the intact granulomas were incubated in a shaking water bath at 37°C for 30 min in RPMI containing 0.5% collagenase (type 1 from Clostridium histolyticum; Sigma, St. Louis, MO). The softened granulomas were disrupted further by repeated suction and expulsion through a 1-ml syringe. The dispersed granuloma cell suspensions were passed through a sterile gauze to exclude nondispersed fragments. The cells were collected by centrifugation, washed three times in RPMI, and counted. Cell viability was determined by eosin Y exclusion.
Single-cell suspensions of splenocytes were prepared from individual spleens from 8-wk-infected or uninfected mice by gentle teasing in RPMI. The cells were briefly resuspended in distilled water to lyse RBC. The splenocytes then were washed three times in a large volume of RPMI.
Cells usually were cultured for 4 h in tissue culture flasks
(Corning, Cambridge, MA) with 25 ml of medium (about 4 x
107 cells/flask) at 37°C. Some cells were cultured for
18 h to collect supernatant for IL-4 measurement by ELISA. The
culture medium was RPMI containing 10% FCS, 10 mM HEPES buffer, 2 mM
L-glutamine, 100 U/ml penicillin, 5 µg/ml gentamicin, and
100 µg/ml streptomycin (all from Sigma). The cells were cultured
alone or in the presence of rIL-10 (30 ng/ml) (R&D Systems,
Minneapolis, MN), LPS (30 µg/ml) (Sigma), IFN- (200 U/ml) (Sigma),
rIL-4 (200 U/ml) (R & D Systems), SP (10-9 to
10-6 M) (Sigma), and/or SP antagonists (10-7
M). The SP antagonists used were CP96,345 (Pfizer, Groton, CT) and SR
140333 (a gift from Dr. X. Emonds-Alt, Sanofi Recherche, France).
SOM extraction
Splenocytes were exposed to the appropriate stimulants for 4 h. SOM then was extracted from splenocytes before chromatography (11). Splenocytes (about 1.5 x 108) were added to 1 ml of 1 M acetic acid solution, which was heated in boiling water for 2 min and then cooled on ice. The cell remnants then were sonicated for six 5-s bursts on ice. Next, the acetified and boiled cell extracts were centrifuged for three 10-min intervals at 630 x g to remove particulate matter. The extracts then were dried in a vacuum concentrator and reconstituted in appropriate solutions for HPLC. Extracts from each of three separate experiments were pooled for each HPLC fractionation and RIA measurement.
HPLC
Extracts first were passed through a Sep-Pak C18 cartridge (Waters Associates, Milford, MA) that was prewetted with 100% acetonitrile followed by 0.05% trifluoroacetic acid (TFA) (Pierce, Rockford, IL) in water. The extracts were loaded onto the cartridge, washed with 0.05% TFA (20 ml), and eluted with 50% acetonitrile in 0.05% TFA (3 ml). The eluates were dried in a vacuum concentrator.
SOM was identified by elution profile using a HPLC system (Waters Associates). Peptide fractionation was performed on a C18 reverse-phase column (Waters Associates). Peptides were eluted over 45 min at a flow rate of 1 ml in using a linear gradient of 20–45% acetonitrile in 0.05% TFA (Pierce). Samples were dissolved in 20% acetonitrile containing 0.05% TFA. To determine the elution time of the immunoreactive SOM, 1-ml fractions of eluate were collected serially, dried, reconstituted in buffer, and assayed for SOM by RIA. The elution time of authentic SOM-14 was determined by injecting synthetic SOM 1–14 (Sigma) into the C18 column and monitoring its elution using a model 440 multiwavelength absorbance detector (Waters Associates) set a 214 nm. Blank control samples were run through the HPLC column before injecting each experimental sample and assayed for SOM by RIA to assure that there was no carryover of SOM between runs.
RIA
Extracts were dissolved in 0.5 ml of 0.1 M Tris-acetate buffer, pH 7.4, containing 0.2% BSA (Sigma). The RIA was performed as previously reported (11). 125I-somatostatin (New England Nuclear, Boston, MA) and rat anti-SOM mAb (S607; a generous gift from Dr. John Walsh, University of California, Los Angeles, CA) were diluted in the Tris-acetate buffer containing 0.2% BSA. Synthetic SOM 1–14 (SOM) was purchased from Sigma.
Immunohistochemistry
Murine splenocytes (5 x 106/well) were incubated at 37°C for 4 h in four-chamber tissue culture slides (Lab-Tek, Nunc, Naperville, IL) with rIL-10 (30 ng/ml). Adherent cell and cytospin preparations (derived from nonadherent cell population) were used for immunohistochemical detection of intracellular SOM. Cytospin preparations were prepared by centrifuging 4 drops of a suspension of cells (1.2 x 106/ml), for 10 min at 32.2 x g onto slides that were precleaned with acid-alcohol (Cytospin II, Shandon Southern Instruments, Sewickley, PA).
Cells preparations were fixed for 5 min in 95% ethanol with 5%
glacial acetic acid (v/v) and washed three times for 5 min each in
Trizma buffer solution (TBS). Slides were submerged for 15 min at room
temperature in TBS containing 0.1% (v/v) Triton X-100 (Sigma),
followed by 5 min in TBS, 2 min in methanol, and 30 min in 3%
H2O2 (v/v) in methanol. Slides subsequently
were washed in methanol for 2 min, TBS for 5 min, and three times in
TBS containing 0.1% (w/v) BSA for 3 min. After treatment with
hyaluronidase (1 mg/ml in 100 mM sodium acetate, 0.85% (w/v) NaCl)
(Type IV-S; Sigma) for 30 min at 37°C, splenocyte preparations were
blocked for 30 min at room temperature with 1% rabbit serum in TBS
containing 0.5% BSA. This was repeated using a blocking kit to block
nonspecific avidin-biotin binding (SP-2001, Vector Laboratories,
Burlingame, CA). Slides were washed three times in TBS, incubated with
anti-FcRII/III mAb (2.4G2, HB-197; American Type Culture
Collection, Manassas, VA) for 30 min at room temperature and washed
three times more in TBS with 0.1% Triton X-100. Splenocyte
preparations were incubated overnight at 4°C in a humidity chamber
with 5 µg/ml biotinylated anti-SOM mAb (CURE.S607) or preabsorbed
S607 as control diluted in TBS containing 0.1% Triton X-100, 1%
rabbit serum, and 0.1% BSA. CURE.S607 was biotinylated using a biotin
reagent (BNHS; Zymed Laboratories, South San Francisco, CA)
according to the instructions from the manufacture. Control mAb was
biotinylated S607 mAb preabsorbed for 30 min at 37°C with 30 M excess
of synthetic SOM 1–14 (Sigma). Cell preparations were washed three
times in TBS with 0.1% BSA. Then, they were exposed to
avidin-horseradish peroxidase (1:1000 dilution; Zymed) followed
by 0.05% diaminobenzidine (Sigma) containing 0.1%
H2O2. Cells were counterstained using Gills No.
III hematoxylin (Sigma).
RNA extraction and competitive PCR assay for SOM cDNA
Each experiment used RNA from splenocytes or granuloma cells pooled from three to four separate mice. Total cellular RNA was extracted from cell suspensions by homogenization in guanidinium/acid-phenol as previously described (12). Cellular RNA (5 µg) was reverse-transcribed with Moloney-monkey leukemia virus (400 U) using an 18-mer of oligo-dT (0.5 µg) as primer. The first strand cDNA was diluted to 250 µl, and 15 µl (0.3 µg RNA) was added to PCR buffer containing 2 U Taq DNA polymerase, 1.4 mM Mg Cl2, 50 mM KCl, and 100 mM Tris, pH 8.3, in a total volume of 50 µl. The sense primer to amplify ppSOM was 5'-ATGCTGTCCTGCCGTCTCCAGT-3', and the anti-sense primer was 5'-ACAGGATGTGAATGTCTTCCAG-3'. The PCR consisted of 35 cycles at 94°C for 1 min, 58°C for 1 min, and 72°C for 1.5 min. Products of RT-PCR amplification was analyzed by agarose gel electrophoresis using 1.7% Nusieve GTG agarose (FMC Bioproducts, Rockland, ME) in 0.5x TBE buffer. The ppSOM competitive mimic plasmid was made as previously described (7). The ppSOM mimic plasmid was 2.219 x 106 g/M. Known quantities of mimic plasmid DNA containing double-stranded abbreviated ppSOM cDNA were added to PCR reactions containing cDNA from mRNA reverse-transcribed with oligo-dT.
Total RNA preparations contained equivalent 18S and 28S RNA bands. RNA extracts were quantified spectrophotometrically. In most experiments, samples were compared for content of actin to further confirm equivalent mRNA content and reverse transcription.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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It previously was shown that LPS, IFN-, and IL-10 induce ppSOM
mRNA expression in dispersed splenocytes from normal CBA, B129 or
C57BL/6 mice cultured in vitro (7). SOM and SP work antagonistically to
modulate IFN- secretion from T cells (1, 2). Because SOM and SP
function in a common IFN- immunoregulatory circuit, it was
determined if SP could affect ppSOM mRNA expression.
Splenocytes from normal CBA mice did not express ppSOM mRNA when
cultured in vitro with SP for up to 18 h. As expected, cells
cultured with LPS, rIFN-, or rIL-10 for as little as 4 h
expressed ppSOM mRNA strongly. However, SP at 10-9 M or
higher strikingly antagonized LPS, rIFN-, or rIL-10 induction of
ppSOM mRNA (Fig. 1
). The inhibition with
10-9 M SP was always >85% as demonstrated by
quantitative PCR (Table I). Also,
this inhibition was sustained when cells were cultured in vitro for up
to 48 h (data not shown). Higher concentrations of SP (i.e.,
10-8 M) frequently resulted in no detectable ppSOM cDNA.
Experiments using LPS or rIFN- gave similar results (Fig. 1 and
Table I).
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Animals infected with S. mansoni form Th2-type granulomas in the liver and intestines resulting from deposition of parasite eggs in these organs. The granulomas contain macrophages that make SOM (13). It was determined if SP could modulate ongoing SOM expression.
Dispersed granuloma cells cultured in vitro for up to 18 h
expressed ppSOM mRNA constitutively. Exposure to LPS, rIFN-, or
rIL-10 did not alter endogenous ppSOM mRNA levels. However, cells
cultured with SP for as little as 4 h had substantially less ppSOM
mRNA. The decrease in ppSOM mRNA expression was >75% or >90% when
SP was used at 10-9 or 10-8 M, respectively
(Fig. 2), as measured by quantitative
PCR (Table II). The SP suppression of
ppSOM mRNA expression was sustained in 18-h cultures (data not shown).
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SP belongs to a family of molecules called tachykinins. It functions through the NK1 receptor. The brain, spleen, and granulomas of mice infected with schistosomiasis express this receptor (4). There are several potent and highly selective nonpeptide NK1 receptor antagonists like SR140333 and CP96345. SR140333 is a NK1 receptor antagonist particularly potent in mice (14). Experiments employed SR140333 and CP96345 to determine whether they could block SP modulation of ppSOM mRNA expression.
Splenocytes from uninfected, normal CBA mice were cultured in vitro
alone or in the presence of rIL-10 with or without SP. Some wells also
contained either of the two SP receptor antagonists. As seen in Fig. 3, SR140333 totally prevented SP from
inhibiting ppSOM induction. CP96345 afforded similar results (data not
shown). Neither inhibitor used alone induced ppSOM
expression.
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also shows that SP receptor antagonists block SP modulation of
ongoing ppSOM expression within dispersed granuloma cells cultured in
vitro. SP can also govern SOM protein production
It next was determined if SP modulation of splenocyte ppSOM mRNA expression resulted in a change in splenocyte SOM content. Splenocytes from uninfected mice were cultured for 4 h in vitro in the presence or absence of rIL-10 and/or SP (10-6 M) in RPMI. Following the incubation, the cells were boiled and sonicated in acetic acid solution to extract SOM. The extracts then were eluted through an HPLC column. The column elutant was collected in 1-ml fractions that subsequently were assayed from SOM content using an RIA.
Immunoreactive SOM only was evident in the elution fraction
corresponding to the elution time of synthetic SOM 1–14. Splenocytes
cultured with rIL-10 for 4 h contained large amounts of authentic
SOM. However, cells exposed to medium containing SP had no detectable
SOM (Table III). The RIA was sensitive
down to 5 pg/ml.
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We previously showed that granuloma macrophages contain SOM. We
used immunohistochemistry, employing an anti-SOM mAb, to locate the
storage site of SOM within the mixed spleen cell population.
Immunoreactive SOM localized solely to mononuclear cells with
bean-shaped nuclei and other morphologic features of macrophages (Fig. 4).
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It is likely that macrophages are the major source of SOM in the granuloma (13) and spleen. The above experiments suggest that SP interacts with unknown cellular elements of the spleen and granuloma to govern ppSOM expression. Rag-1 mutant mice do not produce mature B or T lymphocytes because of mutation in their recombination activation gene (8). Their spleens contain predominantly NK cells and monocytes. We used splenocytes from uninfected Rag-1 mice to determine whether SP could still regulate ppSOM mRNA expression in the absence of mature T or B cells.
Splenocytes from Rag-1 mice can express ppSOM mRNA. Fig. 5 shows that in the absence of T and B
cells, SP still modulates ppSOM mRNA expression. Thus, SP can alter SOM
production without the aid of either T or B cell interactions. Also,
the NK1 receptor antagonist, SR140333, blocks SP modulation of ppSOM
expression in Rag-1 mice.
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Splenocytes from schistosome-infected mice of either the CBA or C57BL/6 strain constitutively express ppSOM mRNA (7). Unlike normal spleen cells from uninfected mice of either strain or granuloma cells, this ppSOM mRNA expression was not subject to SP regulation (data not shown).
Splenocytes from mice infected with schistosomiasis produce IL-4 constitutively, which is not the case for spleen cells from uninfected animals (15). This prompted us to determine whether IL-4 naturally antagonized SP regulation of ppSOM mRNA expression. The first series of experiments studied ppSOM expression and SP regulation in IL-4 mutant mice unable to make IL-4.
C57BL/6 IL-4-/- mice infected with schistosomiasis
expressed ppSOM mRNA in the spleen at levels similar to that of
wild-type controls. However, unlike the IL-4+/+ mice, SP
could abrogate ppSOM mRNA expression in splenocytes from
IL-4-/- animals (Fig. 6)
(Table IV). To explore the importance of
IL-4 in regulating the SP effect, splenocytes from
IL-4-/- mice were cultured for 4 h in the presence
or absence of SP and/or rIL-4 before ppSOM mRNA quantification. Fig. 7 and Table IV show that rIL-4
antagonized SP regulation of ppSOM mRNA expression in IL-4 mutant mice.
Recombinant IL-4 use alone did not affect ppSOM mRNA levels.
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and Table V) show that rIL-4 added to these
cultures prevented SP from antagonizing ppSOM expression. Similar
experiments using splenocytes from normal, uninfected C57BL/6 animals
afforded similar results (data not shown). Once more, rIL-4 used alone
or with rIL-10 did not affect ppSOM mRNA levels.
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).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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-,
and IL-10-induced ppSOM mRNA expression in splenocytes from normal,
uninfected mice. Moreover, SP down-modulates ongoing ppSOM mRNA
expression in granulomas of schistosome-infected animals. Our HPLC data
also suggest that this inhibition in mRNA production results in less
SOM peptide synthesis within the inflammatory cells. As little as
10-9 M SP strongly affects ppSOM expression, and specific
SP receptor antagonists completely inhibited this regulation. This
latter observation implies that the SP operates through the authentic
SP receptor (NK1). Altogether, the above findings further support our
contention that SP regulation of SOM expression is biologicly relevant. As true for SOM, authentic SP and its mRNA are readily detected in schistosome granulomas (6, 10). Schistosome granulomas are focal inflammatory responses rich in eosinophils and macrophages as well as other inflammatory cell types. Unlike SOM, which is made by granuloma macrophages (13), SP in schistosome granulomas probably derives from eosinophils (16). However, additional reports suggest that macrophages from the peritoneal cavity and other locations and the P388 macrophage cell line (17) are other sources of SP.
We showed here, using immunohistochemistry, that macrophages are the likely source of SOM in the spleen. Moreover, macrophage-like but not T or B cell lines contain ppSOM mRNA (7). Splenocytes from Rag-1 mice, which do not have mature T or B cells, expressed ppSOM mRNA, further supporting the above contention.
Inflammatory cells can display the NK1 SP receptor. Some human PBL
(18), murine lymphocytes from Peyer’s patches and spleen (19), and
several B (20, 21) and T cell lines bind SP. In murine schistosomiasis,
splenocytes and dispersed granuloma inflammatory cells express a
functional SP receptor (1) that can signal to enhance IFN-
production (1, 4). Splenocytes, thymocytes, granuloma T cells, and
several granuloma-derived, CD4+ Th2 cell lines express SPr
mRNA (4).
Yet, SP blocked ppSOM mRNA production in Rag-1 splenocytes, suggesting that neither T nor B cells are required for this SP receptor-dependent, regulatory process. Guinea pig (22), rat (23, 24), and mouse (25, 26) peritoneal macrophages also can bind SP. Although not yet fully demonstrated, our experiments using Rag-1 mice suggest that SP regulates macrophage SOM synthesis through direct interaction with SP receptors located on these cells.
SP can increase IFN- production and effect other aspects of immune
responses. In murine schistosomiasis, SP substantially enhances IgG2a
production through its effects on IFN- secretion (3). Also, SP may
increase PWM-induced, duodenal IFN- synthesis in humans (27).
Moreover, a SP antagonist given in vivo to mice impedes an appropriate
IFN- response to intestinal salmonellosis (28). It is possible that
SP affects the production of other regulatory cytokines (29, 30, 31) and Ig
isotypes (21, 32, 33, 34).
Schistosome granulomas contain Th1 cells that are the major source of
IFN- within these lesions (35). SOM inhibits IFN- secretion. The
effect of SP on IFN- and SOM synthesis in schistosomiasis suggests
that SP can promote IFN- production in Th2-type responses both
through stimulating IFN- secreted from T cells and inhibiting SOM
production.
While SP blocks leukocyte ppSOM mRNA expression, IL-4 can counter this
SP regulation. This was demonstrated both in normal C57BL/6 and CBA
mice and in C57BL/6 IL-4-/- animals. Even SP used at
10-6 M proved ineffective in the presence of IL-4. IL-4 is
a Th2 cytokine that induces many of the phenotypic characteristics of a
Th2 response (36). Early expression of IL-4 helps block development of
IFN--producing T cells, whereas, IFN- inhibits growth of IL-4
generating T cells. SP augments T cell IFN- release (1) and thereby
promotes Th1 responses. SOM suppresses T cell IFN- release (2) to
aid Th2 responses. SP inhibits SOM secretion, effectively preventing
SOM-mediated inhibition of IFN- synthesis. In this context,
prevention of the SP effect by IL-4 is important, because IL-4 allows
continued SOM production that in turn further inhibits T cell IFN-
secretion.
However, this IL-4 regulation of SP was not evident in the granuloma. Schistosome granulomas make large amounts of IL-4. Yet, SP was still a powerful inhibitor of SOM mRNA expression in dispersed granuloma cells. Granuloma cells cultured with supplemental rIL-4 also failed to express ppSOM mRNA after SP stimulation, suggesting that insufficient endogenous production of IL-4 was not the deciding factor. Thus, there are probably additional immunoregulatory factors that govern ppSOM mRNA expression at sites of inflammation.
Lymphocytes at mucosal surfaces and at other sites of inflammation are
exposed to multiple Ags. The immune system is under constant
stimulation and must be tightly regulated to avoid needless organ
damage. At mucosal surfaces and other sites of inflammation, SP may
prompt Th1 cells to secrete IFN- and, therefore, inhibit Th2 cell
development. Somatostatin provides the opposite signal, suppressing
IFN- release. Thus, these neuropeptides, which are part of the
innate immune system, may help tune both the intensity and nature of
the T cell inflammatory response. In this report, we showed that SP can
inhibit SOM synthesis by inflammatory cells and that IL-4 can oppose
this action. These new observations further suggest that SP and SOM are
opposing components of an important immunoregulatory
circuit.
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Joel V. Weinstock, Department of Internal Medicine, 4607 JCP, University of Iowa, Iowa City, IA 52242.
3 Abbreviations used in this paper: SP, substance P; SOM, somatostatin; ppSOM, preprosomatostatin; RPMI, RPMI 1640 medium; TFA, trifluoroacetic acid; TBS, Trizma buffer solution; NK1, neurokine 1.
Received for publication March 2, 1998. Accepted for publication August 4, 1998.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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production in murine schistosomiasis mansoni. J. Immunol. 151:225.[Abstract]
secretion. J. Immunol. 149:3621.[Abstract]
immunoregulatory circuit. Ann. NY Acad. Sci. 840:532.[Medline]
secretion by cultured human duodenal mucosa. Immunol. Lett. 23:199.[Medline]
production within the granulomas of murine schistosomiasis in IL-4 deficient and control mice. J. Immunol. 160:4994.This article has been cited by other articles:
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  Y. Zavros, S. Rathinavelu, J. Y. Kao, A. Todisco, J. Del Valle, J. V. Weinstock, M. J. Low, and J. L. Merchant Treatment of Helicobacter gastritis with IL-4 requires somatostatin PNAS, October 28, 2003; 100(22): 12944 - 12949. [Abstract] [Full Text] [PDF]
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 S. F. Elsawa, W. Taylor, C. C. Petty, I. Marriott, J. V. Weinstock, and K. L. Bost Reduced CTL Response and Increased Viral Burden in Substance P Receptor-Deficient Mice Infected with Murine {gamma}-Herpesvirus 68 J. Immunol., March 1, 2003; 170(5): 2605 - 2612. [Abstract] [Full Text] [PDF]
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 P. Robinson, A. C. White, D. E. Lewis, J. Thornby, E. David, and J. Weinstock Sequential Expression of the Neuropeptides Substance P and Somatostatin in Granulomas Associated with Murine Cysticercosis Infect. Immun., August 1, 2002; 70(8): 4534 - 4538. [Abstract] [Full Text] [PDF]
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Y. Chowers, L. Cahalon, M. Lahav, H. Schor, R. Tal, S. Bar-Meir, and M. Levite Somatostatin Through Its Specific Receptor Inhibits Spontaneous and TNF-{alpha}- and Bacteria-Induced IL-8 and IL-1{beta} Secretion from Intestinal Epithelial Cells J. Immunol., September 15, 2000; 165(6): 2955 - 2961. [Abstract] [Full Text] [PDF]
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I. Marriott and K. L. Bost IL-4 and IFN-{gamma} Up-Regulate Substance P Receptor Expression in Murine Peritoneal Macrophages J. Immunol., July 1, 2000; 165(1): 182 - 191. [Abstract] [Full Text] [PDF]
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A. M. Blum, A. Metwali, M. Kim-Miller, J. Li, K. Qadir, D. E. Elliott, B. Lu, Z. Fabry, N. Gerard, and J. V. Weinstock The Substance P Receptor Is Necessary for a Normal Granulomatous Response in Murine Schistosomiasis Mansoni J. Immunol., May 15, 1999; 162(10): 6080 - 6085. [Abstract] [Full Text] [PDF]
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