| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
T Cells Bearing Invariant V6/V1 Induced by Escherichia coli Infection in Mice1
*
Laboratory of Host Defense and Germfree Life, Research Institute for Disease Mechanism and Control, and
First Department of Surgery, Nagoya University School of Medicine, Nagoya, Japan;
Department of Oral Microbiology, Asahi University School of Dentistry, Gifu, Japan; and
§
Department of Host Defense, Research Institute for Microbial Disease, Osaka University, Osaka, Japan
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
T cells was
increased after infection with Escherichia coli in
C3H/HeN mice. We here showed that an i.p. injection with native lipid A
derived from E. coli induced an increase of T
cells in the peritoneal cavity of LPS-responsive C3H/HeN mice and,
albeit to a lesser degree, also in LPS-hyporesponsive C3H/HeJ mice. The
purified T cells from C3H/HeN and C3H/HeJ mice expressed a
canonical TCR repertoire encoded by V6-J1/V1-D2-J2 gene
segments and proliferated in response to the native lipid A derived
from E. coli in a TCR-independent manner. The lipid
A-reactive T cells bearing canonical V6/V1 expressed
Toll-like receptor (TLR) 2 mRNA, while TLR4 mRNA was undetectable.
Treatment with a TLR2 anti-sense oligonucleotide resulted in
hyporesponsiveness of the T cells to the native lipid A.
TLR2-deficient mice showed an impaired increase of the T cells
following injection of native lipid A. These results suggest that TLR2
is involved in the activation of canonical V6/V1 T cells by
native E. coli lipid A. |
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
B in response to LPS binding
(9). Thus, these receptors may function to transfer LPS to
a second receptor that transduces the signal.
Several lines of evidence suggest that the Toll-like receptor
(TLR)3 family is the
cell-surface receptor for LPS, the prototypical activator of NF-B
and other proinflammatory responses (14, 15, 16, 17). Toll was
first identified as a protein controlling dorsoventral pattern
formation in the early development of Drosophila and was
shown to participate in anti-microbial immune responses (18, 19). Recently, several mammalian Toll homologues have been
identified (18, 19, 20, 21, 22). One of the human Toll homologues,
TLR2, has been shown to be involved in LPS signaling
(14, 15, 16). In mice, there is evidence for a missense
mutation in the cytoplasmic domain of TLR4 in C3H/HeJ mice exhibiting
impaired ability to respond to LPS (23, 24), strongly
suggesting that TLR4 is the dominant receptor for at least some types
of LPS. This was confirmed by experiments using TLR4 gene-knockout mice
(25). More recently, it has been suggested that TLR2
functions not only as an LPS signal transducer (14, 16, 26) but also as a receptor for bacterial lipoproteins from
Mycobacteria or Gram-positive bacteria
(27, 28, 29).
Based on the type of TCR they express, T lymphocytes can be divided
into two major groups, 
ß and T cells. T cells are
further divided into subsets, based on their expression of certain -
and -chains and their prevalence in certain tissues. Most of these
subsets bear, as do ß T cells, junctionally diverse TCRs, but two
T cell subsets in the mouse bear invariant TCRs. These include
the V5/V1 subset in skin and the V6/V1 subset that
comprises most of the T cells in the female reproductive tract
(30, 31, 32). Under normal circumstances, these two subsets
bear truly invariant TCRs, even at the nucleotide level in the TCR gene
junction. These canonical sequences are very simple, with no apparent
N-region contribution. Such characteristics have led to the hypothesis
that T cells represent a more primitive, early line of cellular
defense, preprogrammed to recognize a limited set of Ags.
We and others (33, 34, 35) previously reported that i.p.
infection of mice with E. coli induced a marked increase in
T cells in the peritoneal cavity (33, 34, 36) and
that the T cells had a protective role against the infection
(37). In the present study, we focused on the
responsiveness of T cells to native lipid A. Our results
demonstrated that the purified T cells in both C3H/HeN and
C3H/HeJ mice responded to native lipid A from not only E.
coli but also Porphyromonas gingivalis in a
TCR-independent manner. The LPS/lipid A-reactive T cells, which
used a canonical TCR repertoire encoded by
V6-J1/V1-D2-J2 gene segments, strongly expressed TLR2
mRNA. A TLR2 antisense oligonucleotide significantly inhibited the
proliferation of T cells in response to the native lipid A.
TLR2-deficient mice showed an impaired increase of the T cells
following the injection of native lipid A. These results suggest that
the canonical V6/V1 T cells respond to natural products
from E. coli via TLR2. The implications of these findings
for the mechanisms whereby a significant fraction of T cells are
activated during E. coli infection are discussed.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
C3H/HeN and C3H/HeJ mice were purchased from Japan SLC (Shizuoka, Japan). These mice were bred in our institute under specific pathogen-free conditions. Eight- to 10-wk-old female mice were used for the experiments. The mutant mouse (F2 interbred from 129/Ola x C57BL/6) strain deficient in TLR2 was generated by gene targeting, as described previously (29). Age- and sex-matched groups of TLR2-deficient (TLR2-/-) mice and their littermate (TLR2+/-) mice were used for the experiments. E. coli (no. 26; American Type Culture Collection, Manassas, VA) grown in a brain-heart infusion broth (Difco Laboratories, Detroit, MI) was washed repeatedly, resuspended in PBS, and stored at -70°C in small aliquots until use. The concentration of bacteria was quantitated by plate counts.
Abs and reagents
Biotin-conjugated anti-CD3
mAb, FITC-conjugated
anti-TCR ß mAb, PE-conjugated anti-TCR mAb,
purified rat anti-mouse CD11a mAb, PE-conjugated anti-mouse
CD11b mAb, biotin-conjugated anti-mouse CD11c mAb, purified rat
anti-mouse CD14 mAb, and PE-conjugated anti-rat IgG mAb were
purchased from PharMingen (San Diego, CA). Red-613-conjugated
streptavidin was purchased from Life Technologies (Gaithersburg, MD).
Murine anti-TCR (UC7–13D) mAb was obtained by growing
hybridoma cells in serum-free medium (medium 101; Nissui
Pharmaceutical, Tokyo, Japan) and collecting the supernatant. The Ab
was then concentrated and purified by 50% ammonium sulfate
precipitation. The purity of the preparation was confirmed by SDS-PAGE,
and the concentration of Ab was determined by the Lowry method. The
mAbs, diluted to 1 mg/ml in PBS, were stored at -70°C until use. LPS
(E. coli, O26/B6) and lipid A from E. coli (F585
Rd mutant) were obtained from Sigma (St. Louis, MO). Lipid A from
Salmonella minnesota (R595 Rd mutant) was obtained from List
Biological Laboratories (Campbell, CA). Lipid A from P.
gingivalis was prepared as described (6). An E.
coli-type synthetic lipid A analogue with low toxicity (ONO-4007)
was kindly provided by Ono Chemical (Osaka, Japan) (38, 39). LPS was dissolved in pyrogen-free water at the
concentration of 1 mg/ml. Lipid A was dissolved at a concentration of 2
mg/ml in 0.1% (v/v) triethylamine aqueous solution. The solution was
appropriately diluted with pyrogen-free PBS or culture medium before
use for assay.
Cell line
Cell lines were grown as adherent monolayers in tissue culture dishes at 37°C in 5% CO2 with 95% air and passaged twice a week to maintain logarithmic growth. The J774A.1 cell line was obtained from the American Type Culture Collection. The cells growing as monolayers in tissue culture dishes were detached from the surface and washed twice with HBSS before experiments.
Preparation of PEC T cells
Mice were i.p. inoculated with E. coli at a dose of 1x108 CFU/mouse (one-fifth the 50% lethal dose), LPS, or lipid A in 1.0 ml PBS on day 0. Peritoneal exduate cells (PEC) were harvested on day 3 after inoculation by centrifugation at 110 x g for 5 min, washed twice, and resuspended at optimal concentrations in RPMI 1640 medium (Life Technologies) supplemented with 10% serum. Smear specimens for differential counts were stained with Giemsa solution. PEC were spread on plastic plates and incubated for 1 h in a CO2 incubator at 37°C to obtain nonadherent cells.
Sorting of T cells
The T cells were purified by cell sorting using a
FACSVantage (Becton Dickinson, San Jose, CA) electric cell sorter from
the plastic nonadherent cells on day 3 after E. coli or
lipid A injection. The purity of sorted cells was >99% (data not
shown).
Flow cytometry analysis
For three-color analysis, plastic-nonadherent cells of PEC were incubated with saturating amounts of biotin-conjugated and purified Abs for 30 min at 4°C. Cells were washed twice and incubated with FITC-, PE-, and Red-613-conjugated secondary Abs for 30 min. Cells were analyzed with a FACSCalibur flow cytometer (Becton Dickinson). The cells were carefully gated by forward and side light scattering for live lymphocytes. The data were analyzed with FACSCalibur research software (Becton Dickinson).
V gene segment usage analysis
Total RNA was extracted by the acid-guanidium-phenol-chloroform
method from T cells purified by cell sorting. cDNA synthesis and
PCR were performed using a cDNA cycle kit (Invitrogen, San Diego, CA).
RNA was primed either with 20 pmol of -chain C region (C) primers
(5'-CTTATGGAGGATTTGTTTCAGC-3') or 6.7 pmol of -chain J region (J)
primers (5'-TTGGTTCCACAGTCACTTGG-3') in 20-µl reaction mixtures for
reverse transcription. The PCR was performed on a PCR thermal cycler
(Takara, Tokyo, Japan). PCR cycles were run for 30 s at 94°C,
30 s at 54°C, and 30 s at 72°C. Before the first cycle, a
denaturation step for 7 min at 94°C was included, and after 35
cycles the extension was prolonged for 4 min at 72°C. The
5' V primers are as follows: V1/2, 5'-ACACAGCTATACATTGGTAC-3';
V2, 5'-CGGCAAAAAACAAATCAACAG-3'; V4,
5'-TGTCCTTGCAACCCCTACCC-3'; V5, 5'-TGTGCACTGGTACCAACTGA-3';
V6, 5'-GGAATTCAAAAGAAAACATTGTCT-3'; V7,
5'-AAGCTAGAGGGGTCCTCTGC-3'; V1, 5'-ATTCAGAAGGCAACAATGAAAG-3';
V2, 5'-AGTTCCCTGCAGATCCAAGC-3'; V3,
5'-TTCCTGGCTATTGCCTCTGAC-3'; V4, 5'-CCGCTTCTCTGTGAACTTCC-3';
V5, 5'-CAGATCCTTCCAGTTCATCC-3'; V6, 5'-TCAAGTCCATCAGCCTTGTC-3';
V7, 5'-CGCAGAGCTGCAGTGTAACT-3'; V8,
5'-AAGGAAGATGGACGATTCAC-3'.
PCR products (4 µl) were subjected to electrophoresis on a 1.5%
agarose gel (Life Technologies) and transferred to a Gene Screen Plus
filter (New England Nuclear, Boston, MA). The Southern blots of and
PCR products were hybridized with MNG6 cDNA containing the C2
gene, J1 probe (oligonucleotide; 5'-TTGGTTCCACAGTCACTTGG-3'), or
J2 probe (oligonucleotide; 5'-CTCCACAAAGAGCTCTATGCCCA-3'). The C2
probe was labeled with [-32P]dCTP using a
Megaprime DNA labeling system (Amersham International, Amersham, U.K.)
according to the manufacturer’s instructions. The J1 and J2
probes were labeled with [-32P]ATP using a
Megalabel 5' labeling kit (Takara Shuzo, Kyoto, Japan) according to the
manufacturer’s instructions. Before hybridization, the filters were
incubated in 1 M NaCl, 1% SDS, 10% dextran sulfate, and 50 µg/ml
heat-denatured salmon sperm DNA for 18 h at 60°C, and then the
filters were washed in 2x SSC, 1% SDS for 15 min at 60°C. The
radioactivity of each band of PCR product was analyzed with a Fujix
BAS2000 Bio-image analyzer (Fuji, Tokyo, Japan). For nucleotide
sequencing, RT-PCR products were resolved in low-melting-point agarose
gels, isolated, and cloned into the TA vector PCR II (Invitrogen).
Purified dsDNAs were sequenced by using a Taq Dye primer
cycle sequencing kit (Perkin-Elmer, Norwalk, CT) and an Applied
Biosystems 373A DNA sequencer (Applied Biosystems, Foster City,
CA).
Expression of TLR genes
C3H/HeN mice were killed 3 days after i.p. inoculation with
lipid A. Extraction of total RNA from sorted T cells or ß T
cells in PEC, T cells in liver, or J774A.1 (as a positive
control) and cDNA synthesis were performed as described above. Serial
dilutions of total RNA were primed with 20 pmol of random primer (Life
Technologies) in 20-µl reaction mixture for reverse transcription.
Synthesized cDNAs were amplified by PCR with primers derived from the
murine cDNA. The specific primers were as follows: TLR2 sense,
5'-GGAGCGGCGGCTGCAGGACTC-3'; TLR2 antisense,
5'-CCAAAGAGCTCGTAGCATCC-3'; TLR4 sense, 5'-AGTGGGTCAAGGAACAGAAGCA-3';
TLR4 antisense, 5'-CTTTACCAGCTCATTTCTCACC-3' (26).
Proliferation assay
Tissue culture 96-well plates were incubated overnight at 4°C
with 100 µg/ml anti-TCR mAb. The plates were then washed
thoroughly and incubated for 1 h at 37°C with RPMI 1640 medium
containing 10% FCS. The sorted T cells (1 x
105/well) were incubated in the 96-well plates
for 48 h with or without immobilized anti-TCR mAb in
the presence or absence of LPS or lipid A. During the last 8 h of
incubation, 1.0 µCi of [3H]TdR/well was
added. The cells were then harvested, and the amount of
[3H]TdR incorporated was determined by
scintillation counting. In some experiments, the sorted T cells
(1 x 105/well) were cultured with
phosphorothioate-modified anti-sense oligonucleotide (A-ODN),
5'-GACCGCCTGCCCGGAGCCTAGG -3', or sense oligonucleotide (S-ODN),
5'-CCTAGGCTCCGGGCAGGCGGTC-3', specific for mouse TLR2 gene (5 µmol/L)
in the presence of LPS for 48 h at 37°C.
IFN- assay
The sorted T cells (1 x
105/well) were incubated in the anti-TCR
mAb-coated plates for 48 h in the presence of LPS or lipid
A. IFN- levels in the culture supernatants were determined by ELISA
(Genzyme, Cambridge, MA). ELISA for IFN- was performed in triplicate
using Genzyme mAb according to the manufacturer’s instructions.
Statistical analysis
Data were analyzed by Student’s t test, and a Bonferroni correction was applied for multiple comparison. The value of p < 0.05 was considered statistically significant.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
T cells after an i.p. administration of
lipid A
We have previously reported that T cells significantly
increased in the peritoneal cavity of C3H/HeN mice on day 3 after
E. coli infection (37). To determine whether
native lipid A derived from E. coli can induce an increase
in T cells, flow cytometry analysis for the expression of CD3,
TCR ß, and TCR was conducted with nonadherent PEC of
LPS-responsive C3H/HeN mice or LPS-hyporesponsive C3H/HeJ mice on day 3
after the inoculation with LPS or lipid A. A representative result from
three independent experiments is shown in Fig. 1
A. The absolute numbers of
peritoneal T cells were calculated by multiplying the absolute
number of the nonadherent PEC by the percentage of the T cells,
and they are shown in Fig. 1B. The relative number of
T cells in the PEC of C3H/HeN mice were increased, constituting >30%
of the total CD3-positive cell population after inoculation of 100
µg/mouse of LPS or 30 µg/mouse of lipid A (Fig. 1A). The
T cells were also significantly increased in the peritoneal
cavity of C3H/HeJ mice, albeit to a lesser degree compared with those
in C3H/HeN mice (Fig. 1, A and B). There is a
possibility that the native LPS and lipid A include the contaminated
materials such as lipoproteins. Therefore, flow cytometry analyses for
the expression of CD3, TCR ß, and TCR were conducted with
nonadherent PEC of C3H/HeN mice or C3H/HeJ mice on day 3 after the
inoculation with a synthetic lipid A analogue, ONO-4007. A
representative result from three independent experiments is shown in
Fig. 2A. The absolute numbers
of peritoneal T cells were calculated by multiplying the
absolute number of the total nonadherent PEC by the percentage of the
T cells and are shown in Fig. 2B. Both relative and
absolute numbers of the PEC T cells in C3H/HeN and C3H/HeJ mice
were significantly increased after the inoculation of ONO-4007 (1000
µg/mouse), although a >10 times dose of native lipid A was
required.
|
|
and V gene expression by the PEC T cells in the
peritoneal cavity induced by injection with native lipid A
To compare the V gene expressions of the T cells induced by
injection with E. coli, LPS, or lipid A in C3H/HeN and
C3H/HeJ mice, total RNA was extracted from T cells sorted from
nonadherent PEC of mice inoculated with E. coli, LPS, or
lipid A 3 days previously, and the V gene expressions analyzed by
RT-PCR are shown in Fig. 3. The PEC
T cells from naive mice expressed V1/2, 2, 4, and a diversity
of V genes, whereas the PEC T cells of C3H/HeN mice
inoculated with E. coli preferentially expressed V6 and
V1 genes, findings that are consistent with those obtained in our
previous study (37). Similarly, V6 and V1 genes were
exclusively used by the PEC T cells in both C3H/HeN and HeJ mice
injected with LPS or lipid A. These results suggest that the T
cells expressing V6/V1 genes were selectively induced by the
native lipid A, a natural product of E. coli.
|
6-J1 and
V1-J2 gene rearrangements in the T cells induced by the
native lipid A, we examined the nucleotide sequences of the V6 and
V1 transcripts of the peritoneal T cells in the lipid
A-injected mice. As shown in Fig. 4, all
20 V6-J1 transcripts and 18 of 20 V1-J2 transcripts of the
T cells from the lipid A-injected mice showed no junctional
diversity, resulting in in-frame invariant canonical sequences, which
are preferentially expressed in fetal thymocytes at the late stage
(approximately day 17) of gestation (31) and in the
intraepithelial lymphocytes of reproductive organs such as the uterus
(30). Taken together, these results suggest that the lipid
A-induced T cells in the peritoneal cavity expressed a canonical
V6/V1 TCR, which was the same as that of E.
coli-induced T cells.
|
T
cells in response to LPS in vitro
We previously reported that the T cells induced by E.
coli infection in C3H/HeN mice exhibited a strong proliferative
response to LPS even in the absence of APC under TCR engagement
(37). Therefore, we examined the proliferative response
and cytokine production of the lipid A-induced T cells from
C3H/HeN and C3H/HeJ mice in response to LPS. The T cells were
purified by cell sorting from the nonadherent peritoneal cells on day 3
after lipid A injection, and they were incubated for 48 h with
immobilized anti-TCR mAb in the presence or absence of an
optimum dose (10 µg/ml) of LPS. Fig. 5A shows that the lipid
A-induced T cells exhibited a strong proliferative response in
the presence of LPS. Notably, the T cells in LPS-hyporesponsive
C3H/HeJ mice proliferated more vigorously in response to LPS than did
those in LPS-responsive C3H/HeN mice. Fig. 5B shows that
T cells stimulated with LPS produced a large amount of IFN-,
whereas neither IL-2 nor IL-4 was detected in the supernatant (data not
shown). Moreover, the T cells in LPS-hyporesponsive C3H/HeJ mice
produced more IFN- in response to LPS than those did in
LPS-responsive C3H/HeN mice.
|
T cells to LPS is
mediated by TCR signal, sorted T cells induced by lipid A were
incubated for 48 h with or without LPS (10 µg/ml) in the
presence or absence of immobilized anti-TCR- mAb. As shown in
Fig. 6A, the T cells
exhibited a significant proliferative response even without TCR
stimulation, and the proliferative response was augmented by TCR
stimulation. In contrast, Fig. 6B shows that T cells
stimulated with LPS produced a small amount of IFN- in the absence
of TCR stimulation compared with those in the presence of TCR
stimulation. These results suggested that stimulation with LPS induced
T cell proliferation but that TCR stimulation was required for
the IFN- production. Dose responses of LPS for proliferation of
T cells induced by E. coli are shown in Fig. 6C. In the presence of >0.1 µg/ml of the LPS, the
T cells exhibited a significant proliferative response.
|
mAb on the
proliferative response of T cells to LPS. Sorted T cells
induced by native lipid A were incubated for 48 h with the LPS (10
µg/ml) in the presence or absence of an optimum dose (10 µg/ml) of
neutralizing anti-TCR mAb or the same dose of control IgG.
We confirmed that this concentration of anti-TCR mAb could
inhibit the proliferative response of the heat-killed
Salmonella-specific T cells (40). Fig. 7A shows that the
proliferative response to the LPS was not inhibited by the
anti-TCR- neutralizing mAb, confirming that the lipid
A-induced T cells can proliferate in response to the LPS in a
TCR-independent manner.
|
T cells to the lipid A from
P. gingivalis besides the lipid A derived from E.
coli or S. minnesota. When the sorted T cells
were incubated for 48 h with each kind of the lipid A (10
µg/ml), they exhibited a strong proliferative response with each of
them (Fig. 7
B). Taken together with the findings for the
T cells from C3H/HeJ mice, these results suggest that the
T cells respond to the native lipid A using an LPS receptor other than
TLR4, which is mutated in C3H/HeJ mice (23, 24).
Expression of the LPS receptors in the T cells induced by
injection with the native lipid A
CD14 and ß2 integrins (CD11/CD18) have
been widely recognized as LPS receptors for immune cells (3, 7, 8, 9, 10, 11). Recently, two TLR family proteins, TLR2 and 4, have been
identified as LPS signaling receptors (14, 15, 16, 17, 25, 26, 29). We attempted to determine which LPS receptors are used by
the lipid A-induced T cells. Flow cytometry analysis for the
expression of ß2 integrins and CD14 was
conducted with nonadherent PEC on day 3 after the inoculation with
lipid A. A representative result from three independent experiments is
shown in Fig. 8A. The T
cells expressed CD11a but not CD11b, CD11c, or CD14. To examine whether
CD11a is involved in mediating LPS response, sorted T cells were
incubated for 48 h with LPS derived from E. coli (10
µg/ml) in the presence or absence of a neutralizing anti-CD11a
mAb (10 µg/ml) or the same dose of control IgG. As shown in Fig. 8B, the proliferative response of the T cells to LPS
was not inhibited by the neutralizing anti-CD11a mAb.
|
T cells
To examine the TLR2 and TLR4 expressions by T cells, total
RNA was extracted from T cells sorted from nonadherent PEC of
mice inoculated with lipid A 3 days previously, and TLR2 and TLR4
expressions were analyzed by RT-PCR. As shown in Fig. 9A, the T cells in the
peritoneal cavity expressed a significant level of TLR2 mRNA but not
TLR4 mRNA. In contrast, both TLR2 and TLR4 mRNA were only marginally
expressed by the ß T cells in PEC and T cells in the liver,
which did not respond to LPS. Thus, these results suggest that the
T cells in the peritoneal cavity may respond to lipid A via
TLR2. To test this issue, we examined the effect of a TLR2 A-ODN
treatment on the proliferation response of the T cells to LPS.
As shown in Fig. 9B, treatment with the A-ODN reduced the
expression of TLR2 mRNA in the T cells, and the proliferation of
the T cells in response to LPS was significantly impaired by
this treatment compared with that of S-ODN treatment (Fig. 9C). To further confirm the involvement of TLR2 in the
T cell-response to native lipid A, we examined the flow
cytometry analysis for the expression of CD3, TCR ß, and TCR
with nonadherent PEC in
TLR2-/- or
TLR2+/- mice on day 3 after the inoculation of
native lipid A. A representative result from three independent
experiments is shown in Fig. 10A. The absolute numbers of
the peritoneal T cells were calculated by multiplying the
absolute number of the nonadherent PEC by the percentage of T
cells and are shown in Fig. 10B. The increase of T
cells in TLR2+/- mice with C57BL/6/129
background was relatively less as compared with C3H/HeN mice. However,
the increase of T cells following an i.p. injection of lipid A
were significantly impaired in
TLR2-/- mice compared
with that of TLR2+/- mice
(p < 0.05, Fig. 10, A and
B). Thus, these results indicate that TLR2 is at least
partly involved in the proliferation of T cells in response to
the native lipid A from E. coli.
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
T cells is reported to respond to
the LPS fraction through an apparently TCR-independent mechanism
(41, 42, 43). Nitta et al. reported that T cells in the
peritoneal cavity of mice proliferate in response to TCR triggering in
synergy with LPS (43). Leclercq and Plum reported that TCR
V5 cells, which are exclusively associated with canonical V1
chain and are preferentially present in the early fetal thymus and the
epidermis of mice, are activated to produce cytokines upon interaction
with LPS via a TCR-independent pathway (41). Similarly, in
the present study, we found that the T cells expressing
V6/V1 genes responded to native lipid A in vivo and in vitro in a
TCR-independent manner. The T cells in the peritoneal cavity
expressed V6-J1 and V1-J2 mRNA with no N diversity, as they
do in the fetal thymus and uterus. Thus, it would appear that only
primitive T cells with invariant TCR such as V5/V1 and
V6/V1, which develop in the thymus at the early stage of
gestation, respond directly to the bacterial products from
Gram-negative bacteria. We have previously demonstrated that T
cell-deficient mice with a truncated C gene are resistant to
LPS-induced lethal shock with impaired TNF- production
(44). Furthermore, mice depleted of T cells by
TCR- gene mutation showed impaired host defense against E.
coli (37). Like phagocytes, the primitive T
cells may play an important role in innate immunity against bacterial
infection through rapid responses to the bacterial components via
TLR2. Bacterial LPS, a constituent of the outer membrane of the cell wall of Gram-negative bacteria, is one of the main causative agents of septic shock in humans. Recognition of LPS is a key event in host antimicrobial defense reactions. LPS is a complex glycolipid composed of a hydrophilic polysaccharide portion and a hydrophobic domain known as lipid A (45, 46). The conserved lipid A structure has been identified as the LPS component responsible for LPS-induced biological effects (45, 46, 47).
Recently, several members of the mammalian TLR family have been
identified (18, 19, 20, 21, 22). Several lines of evidence suggest
that one or more members of the TLR family are the cell-surface
receptors for LPS, the prototypical activators of NF-B and other
proinflammatory responses (14, 15, 16, 17, 23, 24, 48). In C3H/HeJ
and C57BL/10ScCr mice, mutations of the gene lps
(lpsd) selectively impede LPS
signal transduction, rendering them resistant to endotoxin yet highly
susceptible to Gram-negative infection (23, 24). TLR4 from
the C3H/HeJ mouse has a point mutation at amino acid 712 (Pro to His),
and the C57BL10/ScCr mouse appears to be null for the TLR4 locus
(23, 24). These observations suggested that TLR4 is a
cell-surface component of the LPS signaling pathway. However, although
lpsd mice are hyporesponsive to LPS, they
are not unresponsive, and LPS-dependent gene transcription will occur
if a very large dose of LPS is administered (15).
Moreover, cells from C3H/HeJ mice are nearly as sensitive as their
normal counterparts when stimulated with LPS components derived from
certain bacteria such as P. gingivalis (2, 49).
These observations suggested that proteins other than TLR4 may replace
the function of TLR4 in signal transduction for LPS responsiveness.
Transfection of cell lines with TLR2 confers them with the ability to
respond to LPS with activation of NF-B, thus directly suggesting
that TLR2 serves in place of TLR4 (14, 16, 26). Our
results demonstrated that not only in C3H/HeN mice but also in C3H/HeJ,
the lipid A-induced T cells exhibited a strong proliferative
response in the presence of E. coli native lipid A as well
as the lipid A fraction from P. gingivalis. Furthermore, the
T cells in the peritoneal cavity strongly expressed TLR2 mRNA,
whereas those from the liver that did not respond to the naive LPS in
vitro (37) expressed only a marginal level of TLR2 mRNA.
Treatment with TLR2 A-ODN significantly inhibited the proliferation
response of the T cells to the lipid A. It has to be noted,
though, that the inhibition of cell proliferation was partial. This was
probably because the TLR2 mRNA inhibition by the A-ODN was moderate
(Fig. 9B). In serial dilutions of the samples, the
inhibition was 
75% compared with the S-ODN treatment. Moreover, the
increase of T cells following the i.p. injection of native lipid
A was significantly impaired in
TLR2-/- mice compared
with that of TLR2+/- mice. However, we cannot
exclude the possibility that a minor expression of TLR4 on the T
cells also acts as a LPS receptor for signal transduction in the
T cells in vivo. We previously reported that after E. coli
infection the T cells of the PEC included many V6/V1
T cells but those in the liver did not, and the former exhibited
a strong proliferative response to LPS but the latter did not
(37). Taken together, these results suggested that
V6/V1 T cells responded to the lipid A and that TLR2 in
T cells is responsible, at least partly, for the LPS signaling
in the V6/V1 T cells.
It has recently reported that, TLR2 mediates monocyte activation by
peptidoglycans, lipoteichoic acids, and microbial lipoproteins
(27, 28, 29, 50). Roark et al. reported that V6/V1 T
cells preferentially increase among T cells infiltrating
inflamed tissues induced by infection with Listeria
monocytogenes, a Gram-positive bacteria (51).
Takeuchi et al. have most recently reported that TLR4 mainly recognize
lipid A and lipoteichoic acid from Gram-negative or -positive bacteria,
respectively, whereas TLR2 plays a major role in recognition of
peptidoglycan and lipoprotein from both Gram-negative or -positive
bacteria (29). The primitive T cells may play
protective roles in infection with not only Gram-negative bacteria but
also Gram-positive bacteria via TLR2 signal. The native LPS and lipid A
we used here may contain some bacterial proteins, raising a possibility
that bacterial proteins contaminated in LPS stimulate the V6/V1
T cells via TLR2. However, the experiments using a synthetic
lipid A analogue, ONO-4007, which does not contain any other bacterial
materials, demonstrated that it induced an increase of T cells
in the peritoneal cavities in the C3H/HeJ mice that have the mutated
TLR4 gene. These results indicate that TLR2 serve to function as one of
the lipid A signaling receptors. The ability of ONO-4007 to induce
T cells in the PEC was lower than that of the naive lipid A.
Hence, it is possible that the T cells respond more vigorously
to the naive lipid A than synthetic lipid A via TLR2-mediating signals
for contaminated materials such as lipoproteins.
In the present study, the T cells from C3H/HeJ mice responded
more vigorously to LPS in vitro compared with those from C3H/HeN mice.
Nevertheless, the T cells were increased less in C3H/HeJ mice
than in C3H/HeN mice after in vivo administration of lipid A, similar
to E. coli infection as reported previously
(37). Skeen and Ziegler reported that the peritoneal
T cells proliferated in response to IL-1 and IL-7
(52). It has been reported that TNF- and IL-12
synergistically stimulate human T cell proliferation
(53). We have previously reported that T cells
proliferate in response to IL-15 in vitro (37, 54).
Therefore, these cytokines derived from infected macrophages may
preferentially stimulate the invariant T cells to proliferate in
the inflamed sites. We have previously demonstrated that the
macrophages induced by E. coli infection in C3H/HeJ mice
showed an impaired expression of monokine genes such as TNF-, IL-6,
IL-12, and IL-15 compared with those in C3H/HeN mice (37).
Administration of anti-IL-15 mAb inhibited, albeit partially, the
increase in T cells after E. coli infection in
C3H/HeN mice (37). Therefore, IL-15 derived from
LPS-stimulated macrophages may be partly responsible for local
expansion of T cells in the peritoneal cavity in vivo.
Furthermore, IL-15 is reported to have a strong chemotactic activity
for T cells (55, 56). Thus, impaired accumulation and
expansion of T cells in C3H/HeJ mice after in vivo
administration of the native lipid A may be attributable in part to
impaired cytokine production by macrophages that may preferentially use
TLR4 for LPS signaling.
In conclusion, T cells expressing invariant V6/V1 TCR
responded to the native lipid A not only from E. coli but
also from P. gingivalis in a TCR-independent manner. The
LPS/lipid A-reactive T cells expressed TLR2 mRNA but no
detectable TLR4 mRNA. Treatment with TLR2 A-ODN significantly inhibited
the proliferative response of T cells to the lipid A.
Additionally, TLR2-deficient mice showed an impaired increase of the
T cells following in vivo injection of the native lipid A. These
results suggest that the invariant V6/V1 T cells respond
to the lipid A fraction via TLR2. The primitive T cells bearing
invariant TCR may play an important role in innate immunity against
microbial infection through TLR2 activation.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Tetsuya Matsuguchi, Laboratory of Host Defense and Germfree Life, Research Institute for Disease Mechanism and Control, Nagoya University School of Medicine, 65 Tsurumai-cho Showa-ku Nagoya 466-8550, Japan.
3 Abbreviations used in this paper: TLR, Toll-like receptor; PEC, peritoneal exudate cells; A-ODN, anti-sense oligonucleotide; S-ODN, sense oligonucleotide; lpsd, mutations of the gene lps.
Received for publication December 27, 1999. Accepted for publication May 3, 2000.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
T cell receptor repertoire of murine T cells associated with the vaginal epithelium. J. Immunol. 147:1773.[Abstract]
genes: implications for T cell lineages and for a novel intermediate of V-(D)-J joining. Cell 59:859.[Medline]
5 and V6 TCR+ lymphocytes are derived from a common distinct lineage. J. Immunol. 151:4523.[Abstract]
T cells induced by Escherichia coli infection in mice. Immunology 88:261.[Medline]
T cells induced by Escherichia coli infection in mice: correlation between Thy-1 phenotype and host minor lymphocyte-stimulating phenotype. J. Immunol. 151:2062.[Abstract]
T cells at the infected site. Eur. J. Immunol. 29:3877.[Medline]
T cells and interleukin-15 in Escherichia coli infection in mice. Infect. Immun. 66:3270.ß T cells with potent cytotoxicity in the liver of mice via production of IL-12 from Kupffer cells. J. Immunol. 156:2436.[Abstract]
ß T cells in IL-12 production during Salmonella infection. J. Immunol. 163:2057.3 cells by Gram-negative bacteria. J. Immunol. 154:5313.[Abstract]
T cells and their role in resistance to bacterial infection. J. Exp. Med. 178:971. T cell receptor. J. Endotoxin Res. 1:101.
T cells in priming macrophages to produce tumor necrosis factor-. Eur. J. Immunol. 25:1465.[Medline]
+ T cell receptor invariant subset during bacterial infection. J. Immunol. 156:2214.[Abstract]
ß and T cells from Listeria-infected mice: synergistic effects of interleukin 1 and 7 on T cells. J. Exp. Med. 178:985. T cells: synergistic effect of tumor necrosis factor-. Eur. J. Immunol. 26:3066.[Medline]
T cells induced by Salmonella infection. J. Immunol. 156:663.[Abstract]
This article has been cited by other articles:
|
|
 |
|
  A. S. Ismail, C. L. Behrendt, and L. V. Hooper Reciprocal Interactions between Commensal Bacteria and {gamma}{delta} Intraepithelial Lymphocytes during Mucosal Injury J. Immunol., March 1, 2009; 182(5): 3047 - 3054. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. T. Spencer, G. Abate, A. Blazevic, and D. F. Hoft Only a Subset of Phosphoantigen-Responsive {gamma}9{delta}2 T Cells Mediate Protective Tuberculosis Immunity J. Immunol., October 1, 2008; 181(7): 4471 - 4484. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Asprodites, L. Zheng, D. Geng, C. Velasco-Gonzalez, L. Sanchez-Perez, and E. Davila Engagement of Toll-like receptor-2 on cytotoxic T-lymphocytes occurs in vivo and augments antitumor activity FASEB J, October 1, 2008; 22(10): 3628 - 3637. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Spiller, S. Dreher, G. Meng, A. Grabiec, W. Thomas, T. Hartung, K. Pfeffer, H. Hochrein, H. Brade, W. Bessler, et al. Cellular Recognition of Trimyristoylated Peptide or Enterobacterial Lipopolysaccharide via Both TLR2 and TLR4 J. Biol. Chem., May 4, 2007; 282(18): 13190 - 13198. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Shibata, H. Yamada, H. Hara, K. Kishihara, and Y. Yoshikai Resident V{delta}1+ {gamma}{delta} T Cells Control Early Infiltration of Neutrophils after Escherichia coli Infection via IL-17 Production J. Immunol., April 1, 2007; 178(7): 4466 - 4472. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Grabig, D. Paclik, C. Guzy, A. Dankof, D. C. Baumgart, J. Erckenbrecht, B. Raupach, U. Sonnenborn, J. Eckert, R. R. Schumann, et al. Escherichia coli Strain Nissle 1917 Ameliorates Experimental Colitis via Toll-Like Receptor 2- and Toll-Like Receptor 4-Dependent Pathways Infect. Immun., July 1, 2006; 74(7): 4075 - 4082. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A Ogawa, T Tagawa, H Nishimura, T Yajima, T Abe, T Arai, M Taniguchi, K Takeda, S Akira, Y Nimura, et al. Toll-like receptors 2 and 4 are differentially involved in Fas dependent apoptosis in Peyer's patch and the liver at an early stage after bile duct ligation in mice Gut, January 1, 2006; 55(1): 105 - 113. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. W. Askenase, A. Itakura, M. C. Leite-de-Moraes, M. Lisbonne, S. Roongapinun, D. R. Goldstein, and M. Szczepanik TLR-Dependent IL-4 Production by Invariant V{alpha}14+J{alpha}18+ NKT Cells to Initiate Contact Sensitivity In Vivo J. Immunol., November 15, 2005; 175(10): 6390 - 6401. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Kotsiopriftis, J. E. Tanner, and C. Alfieri Heat Shock Protein 90 Expression in Epstein-Barr Virus-Infected B Cells Promotes {gamma}{delta} T-Cell Proliferation In Vitro J. Virol., June 1, 2005; 79(11): 7255 - 7261. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Hedges, K. J. Lubick, and M. A. Jutila {gamma}{delta} T Cells Respond Directly to Pathogen-Associated Molecular Patterns J. Immunol., May 15, 2005; 174(10): 6045 - 6053. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Sturm, K. Rilling, D. C. Baumgart, K. Gargas, T. Abou-Ghazale, B. Raupach, J. Eckert, Ralf. R. Schumann, C. Enders, U. Sonnenborn, et al. Escherichia coli Nissle 1917 Distinctively Modulates T-Cell Cycling and Expansion via Toll-Like Receptor 2 Signaling Infect. Immun., March 1, 2005; 73(3): 1452 - 1465. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. K. Lahmers, J. Norimine, M. S. Abrahamsen, G. H. Palmer, and W. C. Brown The CD4+ T cell immunodominant Anaplasma marginale major surface protein 2 stimulates {gamma}{delta} T cell clones that express unique T cell receptors J. Leukoc. Biol., February 1, 2005; 77(2): 199 - 208. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Shimizu, K. Sasaki, M. Kato, H. Arimitsu, S. Ochi, N. Shigemori, E. B. Wasito, T. Yokochi, and T. Tsuji Induction of Thymus-Derived {gamma}{delta} T Cells by Escherichia coli Enterotoxin B Subunit in Peritoneal Cavities of Mice Clin. Vaccine Immunol., January 1, 2005; 12(1): 157 - 164. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F Y Liew, M Komai-Koma, and D Xu A toll for T cell costimulation Ann Rheum Dis, November 1, 2004; 63(suppl_2): ii76 - ii78. [Full Text] [PDF]
|
|
|
|
|
|
T. Tagawa, H. Nishimura, T. Yajima, H. Hara, K. Kishihara, G. Matsuzaki, I. Yoshino, Y. Maehara, and Y. Yoshikai V{delta}1+ {gamma}{delta} T Cells Producing CC Chemokines May Bridge a Gap between Neutrophils and Macrophages in Innate Immunity during Escherichia coli Infection in Mice J. Immunol., October 15, 2004; 173(8): 5156 - 5164. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. A. Eaton, S. M. Logan, P. E. Baker, R. A. Peterson, M. A. Monteiro, and E. Altman Helicobacter pylori with a Truncated Lipopolysaccharide O Chain Fails To Induce Gastritis in SCID Mice Injected with Splenocytes from Wild-Type C57BL/6J Mice Infect. Immun., July 1, 2004; 72(7): 3925 - 3931. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Odyniec, M. Szczepanik, M. P. Mycko, M. Stasiolek, C. S. Raine, and K. W. Selmaj {gamma}{delta} T Cells Enhance the Expression of Experimental Autoimmune Encephalomyelitis by Promoting Antigen Presentation and IL-12 Production J. Immunol., July 1, 2004; 173(1): 682 - 694. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. E. Gelman, J. Zhang, Y. Choi, and L. A. Turka Toll-Like Receptor Ligands Directly Promote Activated CD4+ T Cell Survival J. Immunol., May 15, 2004; 172(10): 6065 - 6073. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Nishimura, T. Yajima, Y. Kagimoto, M. Ohata, T. Watase, K. Kishihara, F. Goshima, Y. Nishiyama, and Y. Yoshikai Intraepithelial {gamma}{delta} T Cells May Bridge a Gap between Innate Immunity and Acquired Immunity to Herpes Simplex Virus Type 2 J. Virol., May 1, 2004; 78(9): 4927 - 4930. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. K. Aydintug, C. L. Roark, X. Yin, J. M. Wands, W. K. Born, and R. L. O'Brien Detection of Cell Surface Ligands for the {gamma}{delta} TCR Using Soluble TCRs J. Immunol., April 1, 2004; 172(7): 4167 - 4175. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Komai-Koma, L. Jones, G. S. Ogg, D. Xu, and F. Y. Liew TLR2 is expressed on activated T cells as a costimulatory receptor PNAS, March 2, 2004; 101(9): 3029 - 3034. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. N. Cunningham, Y. Wang, R. Guo, G. He, and R. J. Quigg Role of Toll-Like Receptor 4 in Endotoxin-Induced Acute Renal Failure J. Immunol., February 15, 2004; 172(4): 2629 - 2635. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. L. Roark, M. K. Aydintug, J. Lewis, X. Yin, M. Lahn, Y.-S. Hahn, W. K. Born, R. E. Tigelaar, and R. L. O'Brien Subset-specific, uniform activation among V{gamma}6/V{delta}1+ {gamma}{delta} T cells elicited by inflammation J. Leukoc. Biol., January 1, 2004; 75(1): 68 - 75. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Penido, A. Vieira-de-Abreu, M. T. Bozza, H. C. Castro-Faria-Neto, and P. T. Bozza Role of Monocyte Chemotactic Protein-1/CC Chemokine Ligand 2 on {gamma}{delta} T Lymphocyte Trafficking during Inflammation Induced by Lipopolysaccharide or Mycobacterium bovis Bacille Calmette-Guerin J. Immunol., December 15, 2003; 171(12): 6788 - 6794. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Hedges, J. C. Graff, and M. A. Jutila Transcriptional Profiling of {gamma}{delta} T Cells J. Immunol., November 15, 2003; 171(10): 4959 - 4964. [Full Text] [PDF]
|
|
|
|
|
|
G. R. Klimpel, M. A. Matthias, and J. M. Vinetz Leptospira interrogans Activation of Human Peripheral Blood Mononuclear Cells: Preferential Expansion of TCR{gamma}{delta}+ T Cells vs TCR{alpha}{beta}+ T Cells J. Immunol., August 1, 2003; 171(3): 1447 - 1455. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Fenhalls, G. R. Squires, L. Stevens-Muller, J. Bezuidenhout, G. Amphlett, K. Duncan, and P. T. Lukey Associations between Toll-Like Receptors and Interleukin-4 in the Lungs of Patients with Tuberculosis Am. J. Respir. Cell Mol. Biol., July 1, 2003; 29(1): 28 - 38. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Sakaguchi Control of Immune Responses by Naturally Arising CD4+ Regulatory T Cells That Express Toll-like Receptors J. Exp. Med., February 17, 2003; 197(4): 397 - 401. [Full Text] [PDF]
|
|
|
|
|
|
I. Caramalho, T. Lopes-Carvalho, D. Ostler, S. Zelenay, M. Haury, and J. Demengeot Regulatory T Cells Selectively Express Toll-like Receptors and Are Activated by Lipopolysaccharide J. Exp. Med., February 17, 2003; 197(4): 403 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. M. Naiman, S. Blumerman, D. Alt, C. A. Bolin, R. Brown, R. Zuerner, and C. L. Baldwin Evaluation of Type 1 Immune Response in Naive and Vaccinated Animals following Challenge with Leptospira borgpetersenii Serovar Hardjo: Involvement of WC1+{gamma}{delta} and CD4 T Cells Infect. Immun., November 1, 2002; 70(11): 6147 - 6157. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. E. Applequist, R. P. A. Wallin, and H.-G. Ljunggren Variable expression of Toll-like receptor in murine innate and adaptive immune cell lines Int. Immunol., September 1, 2002; 14(9): 1065 - 1074. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Tsuboi, Y. Yoshikai, S. Matsuo, T. Kikuchi, K.-I. Iwami, Y. Nagai, O. Takeuchi, S. Akira, and T. Matsuguchi Roles of Toll-Like Receptors in C-C Chemokine Production by Renal Tubular Epithelial Cells J. Immunol., August 15, 2002; 169(4): 2026 - 2033. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H.-Y. Hsu and M.-H. Wen Lipopolysaccharide-mediated Reactive Oxygen Species and Signal Transduction in the Regulation of Interleukin-1 Gene Expression J. Biol. Chem., June 14, 2002; 277(25): 22131 - 22139. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Wang, H. Das, A. Kamath, L. Li, and J. F. Bukowski Human V{gamma}2V{delta}2 T Cells Augment Migration-Inhibitory Factor Secretion and Counteract the Inhibitory Effect of Glucocorticoids on IL-1{beta} and TNF-{alpha} Production J. Immunol., May 15, 2002; 168(10): 4889 - 4896. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. G. A. M. Wolfs, W. A. Buurman, A. van Schadewijk, B. de Vries, M. A. R. C. Daemen, P. S. Hiemstra, and C. van 't Veer In Vivo Expression of Toll-Like Receptor 2 and 4 by Renal Epithelial Cells: IFN-{gamma} and TNF-{alpha} Mediated Up-Regulation During Inflammation J. Immunol., February 1, 2002; 168(3): 1286 - 1293. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Li, Y. Wang, L. Gao, J. Zhang, J. Shao, S. Wang, W. Feng, X. Wang, M. Li, and Z. Chang Expression of Toll-like Receptors 2 and 4 and CD14 during Differentiation of HL-60 Cells Induced by Phorbol 12-Myristate 13-Acetate and 1{alpha}, 25-Dihydroxy-Vitamin D3 Cell Growth Differ., January 1, 2002; 13(1): 27 - 38. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Wang, W. P. Lafuse, and B. S. Zwilling NF{kappa}B and Sp1 Elements Are Necessary for Maximal Transcription of Toll-like Receptor 2 Induced by Mycobacterium avium J. Immunol., December 15, 2001; 167(12): 6924 - 6932. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. W. Jones, T. K. Means, K. A. Heldwein, M. A. Keen, P. J. Hill, J. T. Belisle, and M. J. Fenton Different Toll-like receptor agonists induce distinct macrophage responses J. Leukoc. Biol., June 1, 2001; 69(6): 1036 - 1044. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. E. Wang, A. Warris, E. A. Ellingsen, P. F. Jorgensen, T. H. Flo, T. Espevik, R. Solberg, P. E. Verweij, and A. O. Aasen Involvement of CD14 and Toll-Like Receptors in Activation of Human Monocytes by Aspergillus fumigatus Hyphae Infect. Immun., April 1, 2001; 69(4): 2402 - 2406. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Dziarski, Q. Wang, K. Miyake, C. J. Kirschning, and D. Gupta MD-2 Enables Toll-Like Receptor 2 (TLR2)-Mediated Responses to Lipopolysaccharide and Enhances TLR2-Mediated Responses to Gram-Positive and Gram-Negative Bacteria and Their Cell Wall Components J. Immunol., February 1, 2001; 166(3): 1938 - 1944. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. da Silva Correia, K. Soldau, U. Christen, P. S. Tobias, and R. J. Ulevitch Lipopolysaccharide Is in Close Proximity to Each of the Proteins in Its Membrane Receptor Complex. TRANSFER FROM CD14 TO TLR4 AND MD-2 J. Biol. Chem., June 8, 2001; 276(24): 21129 - 21135. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
