| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Laboratory of Molecular Immunoregulation, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Regulation of DC trafficking in vivo, like trafficking of other
leukocytes, is presumably influenced by many mediators
(3). However, the capacity of iDC and mDC to migrate to
different anatomical sites is primarily determined by their
differential expression of receptors specific for chemokines and
classical chemoattractants (2, 4). Of the 17 chemokine
receptors identified to date, in vitro studies have shown that iDC
express CXC chemokine receptor 1, -2, and -4 and CCR1, -2, -3, -4, -5,
and -6 and are able to migrate in response to their respective ligands
(4, 5, 6). In contrast, mDC express CXC chemokine receptor 4
and CCR7 and thus are able to migrate, respectively, in response to
stromal cell-derived chemokine-1/CXCL12 and CCR7 ligands, including
6Ckine/secondary lymphoid organ chemokine/exodus-2/CCL21 and macrophage
inflammatory protein-3
/EBI1 ligand chemokine/exodus-3/CCL19
(2, 4, 7). The in vivo contribution of CCR6 to iDC
migration and that of CCR7 to mDC trafficking have been confirmed
recently (8, 9, 10), indicating that in vitro investigation
of the expression of chemotactic receptors by DC provides a useful step
for defining DC trafficking.
The receptors for classical chemoattractants, including bacterial
formyl peptides such as fMLP, C5a, and platelet-activating factor (PAF)
may also contribute to regulating trafficking of DC precursors and DC.
Monocytes, the precursors of myeloid DC, are known to express the
receptors for and be able to respond to fMLP, C5a, and PAF.
Furthermore, human monocyte-derived myeloid iDC respond chemotactically
to and express the receptor for PAF (11). DC isolated from
both rat respiratory tract tissue and mouse skin or generated in vitro
from human peripheral blood monocytes can be chemoattracted by fMLP and
C5a (12, 13, 14). We have previously found that while iDC
express both C5aR and formyl peptide receptor (FPR), mDC only express
C5aR, but not FPR (15). In humans two functional receptors
for fMLP exist: the high affinity receptor FPR and a second receptor,
termed FPR-like 1 receptor (FPRL1), which was cloned in 1992 by several
independent groups (16, 17, 18). FPRL1 has a low affinity for
fMLP (17, 19, 20). Subsequently, FPRL1 was also reported
to be a functional high affinity receptor for lipoxin A4 and given
another name, LXA4R (21). FPRL1 has 
90% homology with
FPR at the nucleotide level (16, 17, 18), and the genes for
FPRL1 and FPR are located in the same region (q13.3) of chromosome 19
(16, 20, 22). Thus, it has been proposed that FPRL1 and
FPR expression may be coordinately regulated (20).
Because functional FPR is present in iDC and down-regulated in mDC (15), we investigated whether FPRL1 is also expressed by iDC and, if so, whether mDC also down-regulate their FPRL1 expression. To our surprise, although human monocytes were fully responsive, monocyte-derived iDC and mDC were unable to respond to an FPRL1-specific ligand with either chemotaxis or Ca2+ flux, indicating that FPRL1 expression might be turned off by the differentiation of monocytes to iDC. This was supported by the fact that monocytes, unlike monocyte-derived iDC, did show FPRL1 expression at the mRNA level. Furthermore, because monocytes are the common precursors for both DC and macrophages, we investigated whether FPRL1 would also be down-regulated as monocytes differentiate into macrophages. However, monocyte-derived macrophages preserved FPRL1 expression at both mRNA and functional levels. Thus, FPRL1 expression in the course of monocyte differentiation into DC and macrophages is differentially regulated. These results reveal another distinction between DC and macrophages and suggest that FPRL1 may serve as a marker to distinguish iDC and macrophages.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
DMEM and RPMI 1640 were purchased from BioWhittaker
(Walkersville, MD). Recombinant human (rh) TNF-
(sp. act., 2 x
107 U/mg), rhGM-CSF (sp. act.,
107 U/mg), and rhIL-4 (sp. act., 2 x
106 U/mg) were purchased from PeproTech (Rocky
Hill, NJ). FITC-conjugated goat anti-mouse IgG Ab, synthetic fMLP,
and C5a were purchased from Sigma (St. Louis, MO). FBS was purchased
from HyClone (Logan, UT). Anti-CD83 was purchased from
Coulter-Immunotech (Marseilles, France). The other Abs used for flow
cytometry were purchased from PharMingen (San Diego, CA).
[3H]TdR (specific radioactivity, 2 Ci/mmol) was
purchased from New England Nuclear (Boston, MA). Su peptide, a shorter
version (without the N-terminal 5 aa) of T21/DP107 corresponding to aa
563–595 of HIV envelope protein gp41, was synthesized and purified by
the Department of Biochemistry, Colorado State University (Fort
Collins, CO). The purity was >90%, and the amino acid composition was
verified by mass spectrometry. The endotoxin levels in dissolved Su
peptide were undetectable.
Human PBMC were isolated from Leukopacks (courtesy of the Transfusion Medicine Department, National Institutes of Health Clinic Center, Bethesda, MD) by routine Ficoll-Hypaque density gradient centrifugation. Monocytes were purified from human PBMC with the use of MACS CD14 monocyte isolation kit (Miltenyi Biotech, Auburn, CA) according to the manufacturer’s recommendation. Human T cells were purified from PBMC by the use of human CD3 T cell enrichment columns (R&D Systems, Minneapolis, MN) following the manufacturer’s recommendation. The purity of monocytes and T cells was checked by FACScan analysis. Cell populations with purity <95% were discarded. Rat basophilic leukemia cells stably transfected with epitope-tagged FPR (ET-FR cells) were provided by Drs. H. Ali and R. Snyderman (Duke University, Durham, NC) and maintained in the presence of 0.8 mg/ml of geneticin in DMEM supplemented with 10% FBS. Human embryonic kidney cells 293 stably transfected with FPRL1 (designated FPRL1 cells thereafter) were maintained in the presence of 2 mg/ml of geneticin in DMEM supplemented with 10% FBS.
DC and macrophage culture
DC were generated as described previously (15).
Briefly, monocytes were differentiated to iDC by incubating them at
1 x 106/ml in RPMI 1640 medium (RPMI 1640
plus 10% FBS, 2 mM glutamine, 25 mM HEPES, 100 U/ml penicillin, and
100 µg/ml streptomycin) in the presence of rhGM-CSF (50 ng/ml) and
rhIL-4 (50 ng/ml) at 37°C in a humidified CO2
(5%) incubator for 7 days. To induce DC maturation, iDC were cultured
in the same cytokine cocktails with added rhTNF- (50 ng/ml) for
48 h at 37°C in a humidified CO2 (5%)
incubator. Macrophages were generated by incubation of purified
monocytes at 1 x 106/ml in RPMI 1640 medium
in the presence of rhM-CSF (50 ng/ml) at 37°C in a humidified
CO2 (5%) incubator for 7 days with the addition
of fresh rhM-CSF-containing medium every 2–3 days
(23).
Chemotaxis assay
Migration of monocytes, DC, ET-FR, and FPRL1 cells in response to chemotactic factors was assessed using a 48-well microchemotaxis chamber technique as previously described (24). Briefly, different concentrations of chemotactic factors were placed in the wells of the lower compartment of the chamber (Neuro Probe, Cabin John, MA), and cells (106 cells/ml) were added to wells of the upper compartment. The lower and upper compartments were separated by either a 5-µm pore size, uncoated (for monocyte and DC) or a 10-µm pore size, collagen-coated (for ET-FR and FPRL1 cells) polycarbonate filter (Osmonics, Livermore, CA). After incubation at 37°C in humidified air with 5% CO2 (1.5 h for monocyte and DC, 5 h for ET-FR and FPRL1 cells), the filters were removed and stained, and the cells migrating across the filter were counted with the use of a BioQuant semiautomatic counting system. The results are presented as the number of cells per high power field.
Calcium flux
Monocytes, macrophages, or DC (107 cells/ml in RPMI 1640 containing 10% FBS) were loaded by incubating with 5 µM fura-2 (Molecular Probes, Eugene, OR) at 24°C for 30 min in the dark. Subsequently, the cells were washed with and resuspended (106 cells/ml) in saline buffer (138 mM NaCl, 6 mM KCl, 1 mM CaCl2, 10 mM HEPES, 5 mM glucose, and 1% BSA, pH 7.4). Each 2 ml of the cell suspension was then transferred into a quartz cuvette, which was placed in a luminescence spectrometer LS50 B (Perkin-Elmer, Beaconsfield, U.K). Ca2+ mobilization of the cells was measured by recording the ratio of fluorescence emitted at 510 nm after sequential excitation at 340 and 380 nm in response to chemotactic factors.
Fluorescence-activated cell sorting
Monocytes, DC, and macrophages (106/sample) were first washed three times with FACS buffer (PBS, 1% FBS, and 0.02% NaN3, pH 7.4), and then stained with mouse mAbs against CD1a, CD14, CD40, CD83, CD86, and HLA-DR or with isotype-matched control Ab (final concentration, 5 µg/ml) at room temperature for 30 min. After washing three times with FACS buffer, the cells were suspended in FACS buffer containing FITC-conjugated goat anti-mouse IgG for 30 min at room temperature. Finally, the stained cells were washed twice with FACS buffer and twice with PBS, fixed with 1% paraformaldehyde in PBS at 4°C overnight, and analyzed the next day with a flow cytometer (EPICS; Coulter, Miami, FL).
Mixed leukocyte reaction
Allogeneic MLR was performed as previously described (5). Briefly, purified allogeneic T cells (105/well) were cultured with different numbers of DC in a 96-well flat-bottom plate for 7 days at 37°C in humidified air with 5% CO2. The proliferative response of T cells was examined by pulsing the culture with [3H]TdR (0.5 µCi/well) for another 18 h before harvesting. [3H]TdR incorporation was measured with a Microbeta counter (Wallac, Gaithersburg, MD).
RNA isolation and RT-PCR
Total RNA from monocytes, DC, and macrophages was isolated by the use of TRIzol reagent (Life Technologies, Grand Island, NY). The RNAs were cleaned by treatment with RNase-free DNase I (Stratagene, La Jolla, CA). RT-PCR was performed by the use of ProSTAR HF Single-Tube RT-PCR System (Stratagene, La Jolla, CA). Briefly, 100 ng of total RNA was used in the RT-PCR. After RT at 37°C for 15 min and inactivation of Moloney murine leukemia virus reverse transcriptase at 95°C for 1 min, FPRL1 and GAPDH cDNA fragments were amplified by 40 cycles of PCR (denaturing at 95°C for 30 s, annealing at 60°C for 30 s, and extension at 68°C for 2 min); reaction with the last extension was performed at 68°C for 10 min. The primers for FPRL1 were 5'-CTGCTGGTGCTGCTGGCAAG-3' and 5'-AATATCCCTGACCCCATCCTCA-3', which enabled the amplification of an 1.1-kb cDNA fragment of FPRL1 as verified by sequencing. The primers for human GAPDH were 5'-GATGACATCAAGAAGGTGGTGAA-3' and 5'-GTCTTACTCCTTGGAGGCCATGT-3', which resulted in the amplification of a fragment of 246 bp as previously described (5). PCR products were identified on 1–2% agarose gel after ethidium bromide staining and photodocumented.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Due to the simultaneous expression of FPR and FPRL1 by monocytes,
an FPRL1-specific agonistic ligand was required to probe the functional
expression of FPRL1. Su peptide, a peptide modified (lacking the
N-terminal 5 aa residues) from T21/DP107 (25), activates
FPRL1 specifically (J. M. Wang, unpublished observation) and was
therefore chosen for this study. Fig. 1
shows that Su peptide only induced the migration of FPRL1-transfected,
not FPR-transfected, cells, confirming the FPRL1 specificity of Su
peptide. To investigate the expression of FPRL1 in the course of DC
differentiation and maturation, we generated iDC by culturing purified
monocytes (DC precursors) for 7 days in the presence of GM-CSF and
IL-4. Mature DC were generated by culturing iDC for 2 days in the
presence of GM-CSF, IL-4, and TNF-. To ensure that iDC and mDC
generated in this manner show characteristics of iDC and mDC, their
surface marker expression and capacity to stimulate allogeneic MLR were
evaluated. As shown in Fig. 2A, iDC were
CD1a+, CD14-, CD40low,
CD83-, CD86low, and HLA-DRmedium,
whereas mDC were CD1a+, CD14-,
CD40high, CD83+, CD86high, and
HLA-DRhigh. In addition, iDC were unable to stimulate
allogeneic MLR, whereas mDC stimulated marked proliferation of
allogeneic T cells at a DC:T cell ratio ranging from 1:100 to 1:10, as
detected by [3H]TdR incorporation (Fig. 2B). These data confirmed that monocyte-derived iDC and mDC
used in this study had the characteristics of iDC and mDC,
respectively.
|
|
A). The possibility that iDC
and mDC were unable to migrate was ruled out, because they migrated as
well as monocytes to SDF-1 (Fig. 3A). Furthermore, Su
peptide induced dose-dependent Ca2+ flux in
monocytes, but could not induce significant Ca2+
flux in iDC derived from monocytes isolated from the same donor (Fig. 3B). Mature DC also did not mobilize
Ca2+ in response to Su peptide (data not shown).
These results suggest that differentiation of monocytes to DC is
associated with down-regulation of functional FPRL1 expression.
|
Due to the unavailability of either FPRL1-specific Ab or
radiolabeled FPRL1-specific ligand, we were unable to investigate FPRL1
expression at the protein level during the differentiation of monocytes
to DC. However, when FPRL1 expression was monitored by RT-PCR, iDC and
mDC did not, while monocytes did, express FPRL1 at the mRNA level (Fig. 4). Amplification of GAPDH by the use of
100 ng of total RNAs isolated from monocytes, monocyte-derived iDC, and
mDC under similar RT-PCR conditions yielded bands of nearly identical
intensities, confirming that equal amounts of RNAs were used in the
RT-PCR for FPRL1 amplification (Fig. 4). Thus, FPRL1 was down-regulated
at the mRNA level by the differentiation of monocytes to DC.
|
Differentiation of monocytes to iDC in vitro took 7 days when
cultured in the presence of GM-CSF and IL-4. To investigate the
kinetics of FPRL1 down-regulation, cells were removed from the culture
at various time points for chemotaxis and extraction of total RNA.
Cells cultured for 1 and 3 days (D1 and D3) responded chemotactically
to Su peptide equally well as freshly isolated monocytes (Fig. 5A). However, the migratory
response of the cultured cells to Su peptide decreased significantly
after 5-day incubation (D5) and was absent after 7-day incubation (D7)
when DC differentiation was complete (Fig. 5A). Similarly,
the expression of FPRL1 mRNA was unchanged in comparison with monocytes
on D1 and D3, but was greatly decreased on D5 and absent in D7 cells
(Fig. 5B). Bands of GAPDH with similar intensity were
obtained for each 100 ng of total RNA isolated from monocytes and D1,
D3, D5, and D7 cells, assuring that identical amounts of RNAs were used
for the amplification of FPRL1 (Fig. 5B). The
down-regulation of FPRL1-mediated chemotactic responsiveness was not
due to a decrease in cell motility, because the random migrations
(without Su peptide) of monocytes and D1, D3, D5, and D7 cells were
similar (Fig. 5A), and all cell populations migrated equally
well as monocytes in response to another chemoattractant human C5a
(Fig. 5A, triangles). In addition, iDC (D7) generated from
monocytes in a similar manner maintained their responsiveness to fMLP
and the expression of FPR, a chemotactic receptor that shows
considerable homology with FPRL1 (data not shown) (15).
Therefore, the down-regulation of FPRL1 expression and function during
DC differentiation begins after 3-day culture and is completed by the
late stage of differentiation of monocytes to iDC.
|
To determine whether differentiation of monocytes to macrophages
also results in a down-regulation of FPRL1 expression, purified human
peripheral blood monocytes were cultured in the presence of M-CSF for 7
days in vitro, a condition known to induce macrophage, but not DC,
differentiation (23, 26). The resulting cells had several
characteristics typical for macrophages: 1) they were adherent; 2) they
expressed similar levels of CD11b, CD14, and CD86 as monocytes (Fig. 6); and 3) they up-regulated their
expression of CD16, CD40, and HLA-DR (Fig. 6). Macrophages and iDC
differentiated from the same batch of purified monocytes were then
tested for their capacity to migrate in response to Su peptide, the
FPRL1-specific agonist. In contrast to iDC that did not respond,
macrophages migrated chemotactically to Su peptide (Fig. 7A). Moreover, macrophages
mobilized Ca2+ in a dose-dependent manner in
response to Su peptide (Fig. 7B). When total RNAs were
isolated from monocytes, iDC, and macrophages and tested for FPRL1
expression by RT-PCR, comparable levels of FPRL1 mRNA were expressed by
monocytes and macrophages, whereas FPRL1 mRNA was absent in iDC (Fig. 7C). Therefore, differentiation of monocytes to macrophages
is associated with persistent FPRL1 expression and function.
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
.
Because chemotactic receptors mediate cell migration through
interacting with their ligands (3, 4, 20), the migration
of DC precursors, iDC and mDC, must be differentially regulated by
agonistic ligands specific for FPRL1, FPR, C5aR, and PAF receptor
(PAFR). Indeed, the migration of monocytes to sites of inflammation is
regulated by classical chemoattractants (20). The
migration of iDC to sites of Ag deposition or inflammation is also
regulated by chemoattractants specific for FPR, C5aR, and PAFR
(12, 27, 28). Because mDC maintain the functional
expression of C5aR and PAFR (11, 15), C5a and PAF
presumably also contribute to the control of mDC trafficking from
peripheral tissues to secondary lymphoid organs and presumably
contribute to the induction of adaptive immune responses. The results
showing functional expression of FPRL1 by monocytic precursors of DC,
but not by DC, suggest that endogenous ligands acting on FPRL1 may play
a role in regulating the extravasation of DC precursors.
|
, and Fc
receptors) to
facilitate Ag capture and specific delivery to the Ag processing
compartment (33, 34, 35), whereas macrophages express more
scavenger receptors (36, 37). In addition, DC, relative to
macrophages, synthesize higher levels of MHC class II molecules and
express more accessory molecules, especially after maturation (1, 5, 15, 23, 26, 32, 35). Furthermore, DC can prime naive T cells
in vitro and in vivo (1, 2). Our results showing that
macrophages, but not iDC, express FPRL1 highlight another distinction
between iDC and macrophages and suggest that FPRL1 may be used as a
marker to distinguish between iDC and macrophages. FPRL1 uses a variety of specific ligands, including Su peptide (used in the present study), lipoxin A4 (21, 38), a lipid derivative of arachidonate metabolism (39), a synthetic peptide analogous to HIV type 1 gp120 (40), and serum amyloid A (41). Very recently, we established that LL-37, the antimicrobial domain of human cathelicidin/human cationic antimicrobial protein 18 (42), is also an FPRL1-specific ligand (24). Of these, lipoxin A4, serum amyloid A, and LL-37 are endogenously generated predominantly during inflammation, atherosclerosis, and bacterial infection (38, 39, 42, 43, 44, 45, 46). Furthermore, serum amyloid A is able to induce tissue infiltration of leukocytes into the site of injection in vivo (47). Thus, FPRL1 may be involved in attracting macrophages and their precursors, monocytes, but not iDC, to tissues where FPRL1-specific endogenous ligands are locally generated. The selective expression of FPRL1 by macrophages may also reflect a physiologically fundamental capacity for macrophages, unlike iDC, to respond to endogenous FPRL1-specific agonistic ligands. One of the endogenous FPRL1-specific ligands, lipoxin A4, has been reported as a potent inhibitor of acute inflammation by suppressing CD11/18 expression and chemokine production of FPRL1-positive cells (38, 48, 49, 50). Serum amyloid A, another endogenous FPRL1-specific agonistic ligand, has also been reported to inhibit the oxidative burst response of neutrophils stimulated by fMLP (51). Thus, the interaction of FPRL1 with its endogenous ligands may have a negative feedback inhibitory effect on FPRL1-positive cells, especially when endogenous FPRL1-specific ligands are produced systemically in large amounts, such as during severe infection. It would be counterproductive for DC to sense lipoxin A4, serum amyloid A, and LL-37, because DC should not be inhibited even during severe systemic inflammation to perform Ag uptake, processing, and presentation. The physiological significance of the differential down-regulation of FPRL1 in iDC, but not in macrophages, needs to be clarified by more in-depth investigation.
FPRL1 was identified and cloned from differentiated HL-60 neutrophils (16, 17, 18). FPRL1 possesses 69% identity at the amino acid level to FPR (16, 17, 18, 20). The FPR and FPRL1 genes are clustered next to each other within a narrow region on human chromosome 19q13.3 (16, 20, 22). FPRL1 and FPR even share some ligands, including fMLP (17, 19, 20), a synthetic peptide termed T21/DP107 that is analogous to an ectodomain of HIV gp41 (25), and a synthetic hexapeptide (Try-Lys-Tyr-Met-Val-D-Met-NH2) termed W peptide (52, 53). Because FPR is expressed by iDC at functional, protein, and mRNA levels (12, 14, 15), it was thus expected that monocyte-derived iDC would also express FPRL1. In this sense the finding that FPRL1 is down-regulated after the differentiation of monocytes to iDC is unique. Human FPRL1 is expressed not only by monocytes, but also by macrophages (the present study), neutrophils (20), lymphocytes (41), and enterocytes (50). The expression of FPRL1/LXA4R by a human enterocyte cell line, the T84 human colonic adenocarcinoma cell line, has recently been shown to be up-regulated by IL-13 and IFN (50). However, how FPRL1 expression in leukocytes is controlled is not clear. Therefore, the process by which FPRL1 down-regulation occurs only as monocytes differentiate into DC, but not as monocytes differentiate into macrophages, needs further investigation.
Collectively, the finding that the functional FPRL1 is selectively expressed by monocyte-derived macrophages but not by monocyte-derived DC suggests that the interaction between FPRL1 and its specific endogenous ligands may play an important role in regulating the trafficking of DC precursors and the accumulation of macrophages at inflammatory sites and is more involved in inflammatory reactions than in adaptive immune responses.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Joost J. Oppenheim, Laboratory of Molecular Immunoregulation, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Building 560, Room 21-89, Frederick, MD 21702-1201.
3 Abbreviations used in this paper: DC, dendritic cell(s); iDC, immature DC; mDC, mature DC; PAF, platelet-activating factor; PAFR, PAF receptor; FPR, formyl peptide receptor; FPRL1, FPR-like 1 receptor; ET-FR cells, epitope-tagged FPR cells; D, day of incubation.
Received for publication October 23, 2000. Accepted for publication January 4, 2001.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
1 express functional C-C chemokine receptor 6. J. Immunol. 163:1737.-Defensins: linking innate and adaptive immunity through dendritic and T cell CCR6. Science 286:525. and inhibits tumor necrosis factor -induced IL-8 release. J. Exp. Med. 187:1285.This article has been cited by other articles:
|
|
 |
|
  R. D. Ye, F. Boulay, J. M. Wang, C. Dahlgren, C. Gerard, M. Parmentier, C. N. Serhan, and P. M. Murphy International Union of Basic and Clinical Pharmacology. LXXIII. Nomenclature for the Formyl Peptide Receptor (FPR) Family Pharmacol. Rev., June 1, 2009; 61(2): 119 - 161. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Devosse, A. Guillabert, N. D'Haene, A. Berton, P. De Nadai, S. Noel, M. Brait, J.-D. Franssen, S. Sozzani, I. Salmon, et al. Formyl Peptide Receptor-Like 2 Is Expressed and Functional in Plasmacytoid Dendritic Cells, Tissue-Specific Macrophage Subpopulations, and Eosinophils J. Immunol., April 15, 2009; 182(8): 4974 - 4984. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Lattin, D. A. Zidar, K. Schroder, S. Kellie, D. A. Hume, and M. J. Sweet G-protein-coupled receptor expression, function, and signaling in macrophages J. Leukoc. Biol., July 1, 2007; 82(1): 16 - 32. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Miao, B. A. Premack, Z. Wei, Y. Wang, C. Gerard, H. Showell, M. Howard, T. J. Schall, and R. Berahovich Proinflammatory Proteases Liberate a Discrete High-Affinity Functional FPRL1 (CCR12) Ligand from CCL23 J. Immunol., June 1, 2007; 178(11): 7395 - 7404. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Karlsson, E. Nygren, J. Karlsson, I. Nordstrom, C. Dahlgren, and K. Eriksson Ability of Monocyte-Derived Dendritic Cells To Secrete Oxygen Radicals in Response to Formyl Peptide Receptor Family Agonists Compared to That of Myeloid and Plasmacytoid Dendritic Cells Clin. Vaccine Immunol., March 1, 2007; 14(3): 328 - 330. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. K. R. Karaolis, T. K. Means, D. Yang, M. Takahashi, T. Yoshimura, E. Muraille, D. Philpott, J. T. Schroeder, M. Hyodo, Y. Hayakawa, et al. Bacterial c-di-GMP Is an Immunostimulatory Molecule J. Immunol., February 15, 2007; 178(4): 2171 - 2181. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-L. Gao, A. Guillabert, J. Hu, Y. Le, E. Urizar, E. Seligman, K. J. Fang, X. Yuan, V. Imbault, D. Communi, et al. F2L, a Peptide Derived from Heme-Binding Protein, Chemoattracts Mouse Neutrophils by Specifically Activating Fpr2, the Low-Affinity N-Formylpeptide Receptor J. Immunol., February 1, 2007; 178(3): 1450 - 1456. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Prat, J. Bestebroer, C. J. C. de Haas, J. A. G. van Strijp, and K. P. M. van Kessel A New Staphylococcal Anti-Inflammatory Protein That Antagonizes the Formyl Peptide Receptor-Like 1 J. Immunol., December 1, 2006; 177(11): 8017 - 8026. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. K. Kang, H.-Y. Lee, M.-K. Kim, K. S. Park, Y. M. Park, J.-Y. Kwak, and Y.-S. Bae The Synthetic Peptide Trp-Lys-Tyr-Met-Val-D-Met Inhibits Human Monocyte-Derived Dendritic Cell Maturation via Formyl Peptide Receptor and Formyl Peptide Receptor-Like 2 J. Immunol., July 15, 2005; 175(2): 685 - 692. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Kurosaka, Q. Chen, F. Yarovinsky, J. J. Oppenheim, and D. Yang Mouse Cathelin-Related Antimicrobial Peptide Chemoattracts Leukocytes Using Formyl Peptide Receptor-Like 1/Mouse Formyl Peptide Receptor-Like 2 as the Receptor and Acts as an Immune Adjuvant J. Immunol., May 15, 2005; 174(10): 6257 - 6265. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. Migeotte, E. Riboldi, J.-D. Franssen, F. Gregoire, C. Loison, V. Wittamer, M. Detheux, P. Robberecht, S. Costagliola, G. Vassart, et al. Identification and characterization of an endogenous chemotactic ligand specific for FPRL2 J. Exp. Med., January 3, 2005; 201(1): 83 - 93. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Yang, Q. Chen, H. F. Rosenberg, S. M. Rybak, D. L. Newton, Z. Y. Wang, Q. Fu, V. T. Tchernev, M. Wang, B. Schweitzer, et al. Human Ribonuclease A Superfamily Members, Eosinophil-Derived Neurotoxin and Pancreatic Ribonuclease, Induce Dendritic Cell Maturation and Activation J. Immunol., November 15, 2004; 173(10): 6134 - 6142. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. de Paulis, N. Montuori, N. Prevete, I. Fiorentino, F. W. Rossi, V. Visconte, G. Rossi, G. Marone, and P. Ragno Urokinase Induces Basophil Chemotaxis through a Urokinase Receptor Epitope That Is an Endogenous Ligand for Formyl Peptide Receptor-Like 1 and -Like 2 J. Immunol., November 1, 2004; 173(9): 5739 - 5748. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Chen, D. Wade, K. Kurosaka, Z. Y. Wang, J. J. Oppenheim, and D. Yang Temporin A and Related Frog Antimicrobial Peptides Use Formyl Peptide Receptor-Like 1 as a Receptor to Chemoattract Phagocytes J. Immunol., August 15, 2004; 173(4): 2652 - 2659. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Sun, P. Iribarren, N. Zhang, Y. Zhou, W. Gong, E. H. Cho, S. Lockett, O. Chertov, F. Bednar, T. J. Rogers, et al. Identification of Neutrophil Granule Protein Cathepsin G as a Novel Chemotactic Agonist for the G Protein-Coupled Formyl Peptide Receptor J. Immunol., July 1, 2004; 173(1): 428 - 436. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Yang, H. F. Rosenberg, Q. Chen, K. D. Dyer, K. Kurosaka, and J. J. Oppenheim Eosinophil-derived neurotoxin (EDN), an antimicrobial protein with chemotactic activities for dendritic cells Blood, November 1, 2003; 102(9): 3396 - 3403. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. M. Bacot, P. Lenz, M. R. Frazier-Jessen, and G. M. Feldman Activation by prion peptide PrP106-126 induces a NF-{kappa}B-driven proinflammatory response in human monocyte-derived dendritic cells J. Leukoc. Biol., July 1, 2003; 74(1): 118 - 125. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Zhang, D. Hodge, T. J. Rogers, and J. J. Oppenheim Ca2+-independent Protein Kinase Cs Mediate Heterologous Desensitization of Leukocyte Chemokine Receptors by Opioid Receptors J. Biol. Chem., April 4, 2003; 278(15): 12729 - 12736. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Yang, Q. Chen, B. Gertz, R. He, M. Phulsuksombati, R. D. Ye, and J. J. Oppenheim Human dendritic cells express functional formyl peptide receptor-like-2 (FPRL2) throughout maturation J. Leukoc. Biol., September 1, 2002; 72(3): 598 - 607. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
) and human embryonic kidney cells 293 stably
transfected with FPRL1 (FPRL1 cells; 
) in response to various
concentrations of Su peptide was assessed by chemotaxis assay. The
results are shown as the average (mean ± SD) of triplicate wells.
Error bars are smaller than the symbols where they are not evident.
Similar results were obtained from three separate experiments.
). The results are
shown as the average (mean ± SD) of triplicate wells. Error bars
are smaller than the symbols where they are not evident.
B, FPRL1 mRNA expression by monocytes and D1, D3, D5,
and D7 (iDC) cells. The RT-PCR products of FPRL1 (upper
panel) and GAPDH (lower panel) were displayed by
1 and 1.5% agarose gels, respectively. Similar results were obtained
from three separate experiments.
) and macrophages
(