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*
Institut National de la Santé et de la Recherche Médicale Unité 430, Hôpital Broussais; and
Institut National de la Santé et de la Recherche Médicale Unité 255, Institut Curie, Paris, France
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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RIII), a
natural ligand of CR3, inhibits the infection of monocytes by primary
R5 HIV-1 strain opsonized with serum of seronegative individuals.
Inhibition of monocyte infection by sCD16 was similar to that observed
with anti-CR3 mAbs, indicating that opsonized HIV may use a
CR3-dependent pathway for entry in monocytic cells. Cultured human
monocytes express both CR3 (CD11b/CD18) and CCR5 receptors. RANTES, the
natural ligand of CCR5, inhibited infection of monocytes with
unopsonized HIV particles and partially that of monocytes infected with
HIV particles opsonized with complement-derived fragments. Although
HIV-infected monocytes from homozygous CCR5 
32/ 32 (CCR5-/-)
individuals produce low levels of p24, cells infected with opsonized
particles produced higher levels of p24 than cells infected with
unopsonized particles. Our results thus suggest that CR3 may represent
an alternative coreceptor to CCR5 of opsonized primary R5 virus entry
into monocytes/macrophages. We also observed that the concentration of
sCD16 is greatly decreased in sera of HIV-infected patients with low
lymphocyte CD4+ counts. Taken together, our findings
suggest that sCD16, present in plasma, may play an important role in
controlling HIV-1 spread. |
Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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RIII, CD16) have been reported to be involved in the entry of
HIV-1 into T-tropic strains (6, 7, 8, 9, 10). In addition,
triggering of CR3 in latently infected monocytes has been shown to
enhance viral replication by intracellular signaling involving nuclear
translocation of NF-
B (11). CR3 is expressed on
phagocytic cells, and its expression is significantly up-regulated on
peripheral blood leukocytes of HIV-infected individuals at advanced
stages of HIV disease (12). CR3 may function as an
adhesion molecule and as a membrane receptor recognizing several
natural ligands, including the iC3b fragment of C3, ICAM-1,
fibronectin, and the soluble form of CD16
(sCD16,3 soluble
FcRIII) (13, 14, 15). sCD16 in plasma originates from
neutrophils following cleavage of the extracellular region of membrane
receptors by metalloproteinases. CD16 plays a regulatory role in a
number of inflammatory processes (16, 17, 18). In the present study, we show that opsonization of HIV-1 R5 strain YU-2 enhances infection of and viral production by monocytes/macrophages. The enhancing effect involves the participation of CR3 (CD11b/CD18) receptors because it is blocked by anti-CR3 mAbs. One of the natural CR3 ligands, sCD16, binds to the lectin-like domain of CR3 and suppressed up to 75% of infection of monocytes with opsonized primary R5 virus strain in vitro. Infection with opsonized virus (OV) is also dependent on CCR5 as anti-CCR5 Abs partially inhibited viral replication. Furthermore, monocytes from individuals lacking a functional CCR5 molecule, which are infected at very low levels, produce higher amounts of p24 when viral particles are opsonized. Infection of CCR5-/- monocytes by OV was inhibited by sCD16 to a higher degree than by RANTES. The concentration of sCD16 was severely depressed in sera of HIV-infected patients with low CD4+ cell counts.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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The cDNA encoding the NA2 form of the human FcRIII-B (CD16)
ecto-domain (194 aa long) was expressed in the baby hamster kidney
(BHK) cell line (18). The JBIXA2 cell line, secreting
sCD16, was grown on hollow fibers in a perfusion cell culture system
(Acusyst Jr.; Endotronics, Minneapolis, MN). sCD16 was purified by
S-Sepharose chromatography (Fast Flow; Pharmacia, Uppsala, Sweden),
followed by affinity chromatography on rabbit IgG-Sepharose and by gel
exclusion chromatography on a Superdex 200 column (Pharmacia)
(19). These purification steps gave pure rsCD16 of
apparent m.w. 47,000–56,000, as indicated by silver staining following
SDS-PAGE and Coomassie blue staining (18, 19).
Purification was performed under endotoxin-free conditions, and sCD16
contained less than 0.1 pg/ml of endotoxin, as determined by the
Limulus assay (Sigma, St. Louis, MO).
Assay of sCD16 in serum
Blood samples were obtained by venipuncture from 100
HIV-infected individuals and 33 seronegative controls. sCD16 level was
measured by an indirect sandwich ELISA. As a capture Ab, we used 3G8, a
mouse IgG11 mAb directed against FcRIII A and B (20)
(kindly provided by Dr. D. Segal, National Institutes of Health), and
as secondary Ab, rabbit polyclonal anti-FcRIII-B Abs. A total of
50 µl of purified mAb 3G8 (5 µg/ml) in PBS was incubated for 2
h at room temperature in each well of ELISA microtiter plates (Nunc
Immunoplate Maxisorb; Nunc, Roskilde, Denmark). Nonspecific binding was
blocked by incubating the plates with 200 µl/well of PBS containing
1% (w/v) BSA (A-7030; Sigma) and 0.01 M sodium azide. After incubation
with each serum for 2 h at room temperature, microtiter plates
were extensively washed with PBS containing 0.05% Tween-20. Purified
rabbit polyclonal anti-FcRIII-B Abs (10 µg/ml in PBS-1%,
BSA-0.01 M sodium azide) were added to each well for 2 h at room
temperature. Plates were washed, and 50 µl of 1/1000 diluted alkaline
phosphatase-labeled goat anti-rabbit (Clinisciences, Paris, France)
was added and incubated for 2 h at room temperature. OD at 405 nm
were recorded with a Titertek Multiscan ELISA reader (Labsystems, Les
Ulis, France). sCD16 concentrations were determined using purified
rsCD16 (100 µg/ml) as standard.
Isolation of cells
Monocytes were isolated from peripheral blood of HIV-1-seronegative individuals. After step-density gradient centrifugation, the PBMC (107/ml) were cultured in RPMI/10% heat-inactivated AB normal human serum (NHS), in plastic tissue culture plates for 1 h at 37°C. After washing, mononuclear adherent cells were cultured in RPMI/10% heat-inactivated FCS, penicillin-streptomycin (50 µg/ml), and 2 mM glutamine for 3–4 days.
Flow cytometric analysis
To determine surface expression of CD4, CCR5, CR3, CD16, and CD14 molecules by monocytes, cells were recovered by adding cold PBS/0.02% EDTA for 10 min, and scraping with a rubber policeman. Cells were washed with PBS/0.01% sodium azide and then incubated with mAbs anti-CD16 FITC, anti-CD4 FITC (Becton Dickinson, Le Pont de Claix, France), anti-CCR5 PE (PharMingen, Le Pont de Claix, France), anti-CD11b PE, anti-CD18 PE, or anti-CD14 PE cyanin S (Immunotech, Beckman Coulter, Villepente, France), or labeled isotype mAb control, for 30 min at 4°C. Following a washing step, cells were fixed with paraformaldehyde (1%) and analyzed using a FACSCalibur flow cytometer and the CellQuest software (Becton Dickinson).
Binding of opsonized and unopsonized gp120 (O-gp120, U-gp120) to cells
Biotinylated O-gp120-IIIB (2 µg/ml; Intracel, Issaquah, WA) was obtained by incubating the recombinant gp120 in the presence of NHS containing CaCl2 (0.6 mM), MgCl2 (0.9 mM) for 30 min at 37°C. O-gp120 and U-gp120 were incubated for 30 min on ice with cells in PBS/0.01% sodium azide/0.2% BSA. In inhibition experiments, cells were preincubated with sCD16 (2 µg/ml) for 30 min at 37°C before adding U-gp120 and O-gp120 (final volume 100 µl). After washing, cells were incubated with streptavidin-conjugated PE (Becton Dickinson) for 30 min on ice and fixed with paraformaldehyde (1%). Binding of O-gp120 and U-gp120 to cells was assessed by flow cytometry (FACSCalibur) and the CellQuest software (Becton Dickinson).
Virus strain
The primary monotropic CCR5-dependent HIV-1 YU-2 strain was used throughout the study. A virus stock was propagated by transfecting 293 T cells with a plasmid encoding the molecular clone of the YU-2 strain (21). Briefly, 10 µg of DNA was introduced into 293 T human embryonic kidney cell line by transfection using the calcium phosphate precipitation method (22). Cell culture supernatants were collected 72 h after transfection and filtered through a 0.2-µm filter. Viral titer was determined using a p24 Ag capture ELISA (HIV-1 core profile ELISA; DuPont de Nemours, Les Ulis, France, or Coulter, Immunotech Company S. A., De Lattre Tassaigny, Marseille, France), and kept at -80°C.
Viral particle opsonization
NHS used as a complement source was a pool obtained from healthy individuals that were seronegative for HIV-1 and HIV-2. Opsonization of HIV-1 YU-2 was achieved by incubating viral particles in NHS containing CaCl2 (0.6 mM), MgCl2 (0.9 mM), and human seronegative serum (OV). Control unopsonized particles were obtained in the presence of human EDTA-chelated plasma before infection (unopsonized virus (UV)). Optimal opsonization was achieved by using a 1/1 dilution in NHS containing CaCl2 and MgCl2.
Infection of monocytes with complement-opsonized or unopsonized HIV-1
Monocytes of healthy individuals cultured for 3–4 days (105/well) were then infected with 2 ng/ml of p24 of HIV-1 YU-2, for 3 h at 37°C. After washing, cells were cultured in RPMI containing antibiotics and 10% heat-inactivated FCS. For inhibition experiments, cells were preincubated for 30 min with anti-CR3 (MO-1/7E4) Abs (10 µg/ml; Immunotech, Beckman Coulter, Villepente, France), sCD16 (0.1–2 µg/ml), denatured sCD16 (den-sCD16; 2 µg/ml), RANTES (500 ng/ml), or stromal-derived factor 1 (2.5 µg/ml) (R&D Systems Europe, Oxon, U.K.) (23). Culture supernatants were harvested every 3 days, and viral replication was quantified by determining the concentration of p24 Ag. Results are expressed as p24 Ag concentrations in pooled supernatants from duplicate culture wells obtained after 3, 6, 9, and 12 days of infection. The HIV-1 DNA was extracted 48 h following infection (Roche Standard Extraction protocol) from cells infected with UV and OV, and quantified by PCR using the HIV-1 MONITOR test (Roche, Meylan, France). In another set of experiments, we compared infection of monocytes from CCR5-/- individuals, cultured under the same conditions, with infection of monocytes from CCR5+/+ subjects.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Peripheral blood monocytes cultured for 3–4 days were incubated
with suboptimal amounts of HIV-1 YU-2 (2 ng/ml) that had been opsonized
with fresh serum obtained from HIV-seronegative donors as a source of
complement. UV was obtained by incubating the particles in
EDTA-chelated serum. The kinetics of infection were monitored by
measuring the release of p24 Ag in culture supernatants. The productive
infection of cells with HIV-1 YU-2 primary strain occurred at higher
rates in cultures grown in the presence of complement-opsonized viral
particles (OV) as compared with UV. The OV/UV ratio of the p24
production ranged between 2 and 6 (Fig. 1
A). Using quantitative PCR,
we observed that the number of viral DNA copies was 5-fold higher in
cells infected with OV than in cells infected with UV (Fig. 1B).
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We first analyzed the expression of CR3 (CD11b/CD18), CCR5, CD4,
and CD16 surface molecules on fresh isolated monocytes or monocytes
that had been cultured for 3–4 days in vitro. The expression of CR3,
CCR5, and CD4 increased on monocytes after 3–4 days of culture (day 0
vs 3–4: CD11b, 79 vs 96%; CD18, 89 vs 97%; CCR5, 26 vs 69%; CD4, 7
vs 19%) (Fig. 2). The culture conditions
did not alter the expression of the monocyte-specific marker, CD14 (86
vs 81%), nor the expression of the macrophage-specific marker, CD16
(0.4 vs 2%).
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(15). In contrast, heat-den-sCD16 had no inhibitory effect
(Fig. 3). sCD16 also had no effect on monocyte infection when viral
particles were incubated in EDTA-chelated serum, thus excluding binding
of sCD16 to putative polyreactive Abs potentially present in
seronegative serum. Preincubation of cells with sCD16 before infection
did not alter expression of CD4, CCR5, and CR3 (data not shown). The
extent of inhibition by sCD16 was similar to that obtained using
saturating amounts of anti-CR3 mAbs (MO-1/7E4) that recognize the
iC3b binding site on CR3. Isotype-matched Abs had no inhibitory effect
under similar experimental conditions (Fig. 4).
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A). SDF-1 had no effect. In
contrast, incubation of monocytes with sCD16 before infection
suppressed viral replication in monocytes infected with OV particles,
whereas RANTES had little effect on infection (Fig. 6B).
Cells were also incubated with mAb anti-CCR5 2D7 Abs. Anti-CCR5 Abs
inhibited infection of monocytes with both OV and UV particles, the
inhibition being greater with anti-CCR5 Abs as compared with RANTES
(Fig. 7). To investigate the exact
involvement of CCR5 in monocyte infection with OV particles, we
compared p24 production by monocytes from
CCR5-/- individuals with cells from
CCR5+/+ subjects. Monocytes lacking CCR5 surface
molecule expressed comparable levels of CR3 as compared with monocytes
CCR5+/+, whereas expression of CCR5 on monocytes
from CCR5-/- individuals was barely or not
detectable (data not shown). Cells were then infected with UV and OV
HIV-1 YU-2 particles. Despite the low p24 production, production of p24
was higher when cells were infected with OV particles as compared with
UV YU-2-infected cells (Fig. 8). When
cells were incubated with sCD16 and RANTES before infection, sCD16
inhibited p24 production by up to 60%, and 15% inhibition was reached
in the presence of RANTES at peak p24 production (day 9) (Fig. 8). To
investigate whether CD4 participates in OV entry, CCR5-positive
monocytes were incubated with soluble CD4 (sCD4; 10 µg/ml) before
infection. Monocyte infection with OV particles was 60–70% inhibited
by sCD4, demonstrating the involvement of CD4 in OV entry (data not
shown).
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We measured sCD16 levels in the serum of 100 HIV-infected
individuals at various stages of HIV disease. Of these, 19 had CD4
counts >500 x 106/L (group A), 22 had CD4
counts between 200 and 500 x 106/L (group
B), and 59 had low CD4 counts <200 x 106/L
(group C). The sera of 33 HIV-seronegative donors were used as
controls. The mean sCD16 level in HIV-infected patients was
significantly lower than that of controls (mean ± SEM =
1440 ± 110 ng/ml and 2670 ± 260 ng/ml, respectively;
p (mean HIV vs controls) = 0.0001). We also observed
that the decrease in sCD16 levels correlated with disease progression.
In patients with CD4 counts above 200 x
106/L, the mean values of sCD16 were 1750 ±
340 (group A) and 1590 ± 140 ng/ml (group B), which are
significantly lower than those of controls (2670 ± 260 ng/ml). In
patients with CD4 counts <200 x 106/L
(group C), mean plasma sCD16 dropped to 770 ± 130 ng/ml, with a
significance of p = 0.0001 as compared with controls
(Fig. 9).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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, and macrophage-inflammatory protein-1
, is the main
coreceptor for primary R5 HIV-1 strains involved in viral entry
(24). Infection of target cells is enhanced by
opsonization of HIV with C3 fragments (7, 25, 26, 27), and
viral entry via complement receptors represents an alternative pathway
for cellular infection (10). CR3 (CD11b/CD18) plays a
central role in phagocytosis, cytotoxicity, and adhesion processes
(28). Natural ligands of CR3 include C3 fragments, sCD16,
and several other molecules interacting with the iC3b binding site or
the lectin binding site specific to microbial polysaccharides
(10, 28, 29). We have previously reported that the
binding of sCD16 to CR3 depends on a lectin binding site of CR3
(15).
In the present study, we investigated the role of sCD16 in viral
replication in cultures of normal human peripheral blood monocytes
infected with a complement-opsonized primary R5 HIV-1 strain (OV-YU2).
Opsonization of HIV-1 using seronegative human serum as a source of
complement results in C3b/iC3b deposition on viral particles (25, 26). Monocytes were infected in 3- to 4-day cultured monocytes
that express the CR3, CD4, and CCR5 receptors on their membrane
surface. In this study, we demonstrate that sCD16 prevents opsonized
HIV-1 YU2 replication in cultured monocytes. This finding extends the
biological functions of sCD16 present in NHS, and indicates that CR3 is
involved in entry of primary R5 HIV-1 strains into cells of the
monocytic lineage in the presence of complement. sCD16 inhibited viral
replication in a dose-dependent manner at concentrations similar to
those present in serum of healthy individuals (30).
Inhibition of viral replication by sCD16 was specific and dependent
upon the tertiary structure of the molecule, as shown by the lack of
inhibitory effect when using a heat-denatured form of sCD16. The
infection of monocytes was abolished by sCD16 in a fashion similar to
that of anti-CR3 mAbs directed against the iC3b binding site. The
results obtained with Abs directed against CR3 extend previous
observations using the laboratory-adapted X4 HIV-IIIB strain (7, 31). Because the addition of sCD16 before infection blocked
viral replication, we suggest that sCD16 inhibits infection of
monocytes with OV by masking both the lectin and iC3b binding sites of
CR3. This hypothesis is corroborated by the finding that anti-CR3
mAbs inhibit the binding of biotinylated sCD16 to monocytes
(15). In addition to blocking CR3 accessibility to OV,
sCD16 may induce internalization of CR3. However, sCD16 did not modify
CR3 expression on cultured monocytes (data not shown). As we used human
serum from HIV-seronegative individuals for opsonization of viral
particles, the enhancing effect of serum on viral replication could
also be due, at least in part, to cross-reacting facilitating Abs.
However, the latter possibility was ruled out because no
immunoreactivity between the serum used as source of complement and the
YU-2 viral strain was found by dot-blot analysis (data not shown).
Moreover, monocytes exhibited a low expression (2%) of FcRIII
receptor (CD16) on their surface. Taken together, the results suggest
that sCD16 may function as a natural inhibitor of opsonized HIV-1 entry
in CR3-expressing target cells.
We further demonstrated that infection of monocytes with OV was partially inhibited by RANTES, the natural ligand of CCR5. Inhibition with anti-CCR5 Abs reached 70%, indicating that CCR5 contribute to the entry of opsonized viral particles. CCR5 involvement is also corroborated by the fact that monocytes from CCR5-/- individuals do not produce high levels of p24 when infected with OV. We also observed that sCD4 inhibited infection of CCR5+/+ monocytes with OV by up to 60–70%, which may suggest that binding of C3b/iC3b-coated virus to CR3 and virus entry still require the conformational changes induced by CD4 to allow viral penetration.
Monocytes from CCR5-/- individuals infected with OV produced higher levels of p24 than those infected with UV (5-fold increase), and the enhancing effect of opsonization was inhibited by sCD16 (60%). Our results demonstrated that infection with UV is CCR5 dependent, as infection is totally inhibited with anti-CCR5, and are in agreement with previous studies (32).
To investigate the in vivo relevance of the inhibitory effect observed with sCD16 in vitro, we determined sCD16 levels in sera of HIV-infected patients. We found that sCD16 levels were greatly decreased in sera of patients as compared with healthy HIV-seronegative controls (p = 0.0001), confirming previous observations (33). The decrease in serum sCD16 levels was a surrogate marker for the progression of HIV disease. A significant difference was found when analyzing the data according to the clinical stages of HIV disease. In patients with CD4 counts below 200 x 106/L, indicating a late stage of HIV disease, the mean values of serum sCD16 were significantly lower than those of groups with CD4 counts above 200 x 106/L (groups A and B) (p = 0.008 and p = 0.001, respectively). A decrease in sCD16 concentrations was also reported in myeloma patients and among healthy blood donors (34). Although we have not yet determined the mechanisms responsible for decreased levels of sCD16 in patients with advanced HIV disease, several possibilities may be suggested. Low serum levels of sCD16 may be due to a decrease in the number of CD16-positive cells and/or a lower expression of CD16 per cell. sCD16 found in human serum is produced mostly by neutrophils (17), and patients with AIDS are often neutropenic (35). However, our patients with low sCD16 levels had neutrophil counts within the normal range. A reduction in membrane CD16 expression, as reported on neutrophils of HIV-1-infected individuals, could also explain such a decrease (36).
The findings that serum levels of sCD16 are decreased in HIV-infected patients and correlate with the severity of HIV disease may suggest a protective role of sCD16 in vivo. Thus, it is conceivable that rsCD16, already proposed as a therapeutic agent for acute immune thrombocytopenic purpura (37) and multiple myeloma (33), may be introduced in the group of immunomodulatory drugs for HIV disease, through its ability to restrict the dissemination of HIV infection of CR3-expressing target cells.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Dr. N. Haeffner Cavaillon, Unité d’Immunopathologie Humaine, Institute National de la Santé et de la Recherche Médicale Unité 430, Pavillon Leriche, Hôpital Broussais, 96 rue Didot, 75674-Paris Cedex 14, France.
3 Abbreviations used in this paper: sCD16, soluble CD16; den-sCD16, denatured sCD16; NHS, normal human serum; O-gp120, opsonized gp120; OV, opsonized virus; sCD4, soluble CD4; SDF-1, ??; U-gp120, unopsonized gp120; UV, unopsonized virus.
Received for publication December 20, 1999. Accepted for publication December 11, 2000.
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References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
, MIP-1 receptor as a fusion cofactor for macrophage-tropic HIV-1. Science 272:1955.[Abstract]
-chemokine receptors CCR-3 and CCR-5 facilitate infection by primary HIV-1 isolates. Cell 85:1135.[Medline]
B (p50/p65) in human monocytes and enhances viral replication in HIV-infected monocytic cells. J. Immunol. 155:4861.[Abstract]
receptor type III (FcRIII, CD16) triggers cell activation through interaction with complement receptors. J. Immunol. 157:1184.[Abstract]
receptor III in human plasma originates from release by neutrophils. J. Clin. Invest. 86:416.
receptor type III (CD16). Eur. J. Immunol. 28:2101.[Medline]
R: detection, purification, and functional activities. ImmunoMethods 4:48.[Medline]
R: production, purification and biological activities. J. Chromatogr. B Biomed. Appl. 662:197.[Medline]
receptor distribution and structure. Proc. Natl. Acad. Sci. USA 79:3275.-glucan-binding lectin site of CR3 (CD11b/CD18). J. Immunol. 162:7285.
ccr5 mutation. J. Virol. 71:3219.[Abstract]
RIII (CD16) on neutrophils from human immunodeficiency virus-infected individuals. Clin. Immunol. Immunopathol. 54:281.[Medline]
fragments for treatment of children with acute immune thrombocytopenic purpura. Lancet 342:945.[Medline]This article has been cited by other articles:
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  M. Alfano, S. A. Mariani, C. Elia, R. Pardi, F. Blasi, and G. Poli Ligand-engaged urokinase-type plasminogen activator receptor and activation of the CD11b/CD18 integrin inhibit late events of HIV expression in monocytic cells Blood, February 19, 2009; 113(8): 1699 - 1709. [Abstract] [Full Text] [PDF]
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 T. E. Morrison, J. D. Simmons, and M. T. Heise Complement Receptor 3 Promotes Severe Ross River Virus-Induced Disease J. Virol., November 15, 2008; 82(22): 11263 - 11272. [Abstract] [Full Text] [PDF]
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 H. Bouhlal, N. Chomont, M. Requena, N. Nasreddine, H. Saidi, J. Legoff, M. D. Kazatchkine, L. Belec, and H. Hocini Opsonization of HIV with Complement Enhances Infection of Dendritic Cells and Viral Transfer to CD4 T Cells in a CR3 and DC-SIGN-Dependent Manner J. Immunol., January 15, 2007; 178(2): 1086 - 1095. [Abstract] [Full Text] [PDF]
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Z. Bajtay, C. Speth, A. Erdei, and M. P. Dierich Cutting Edge: Productive HIV-1 Infection of Dendritic Cells via Complement Receptor Type 3 (CR3, CD11b/CD18) J. Immunol., October 15, 2004; 173(8): 4775 - 4778. [Abstract] [Full Text] [PDF]
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H. Bouhlal, N. Chomont, N. Haeffner-Cavaillon, M. D. Kazatchkine, L. Belec, and H. Hocini Opsonization of HIV-1 by Semen Complement Enhances Infection of Human Epithelial Cells J. Immunol., September 15, 2002; 169(6): 3301 - 3306. [Abstract] [Full Text] [PDF]
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M.-P. Carreno, N. Chomont, M. D. Kazatchkine, T. Irinopoulou, C. Krief, A.-S. Mohamed, L. Andreoletti, M. Matta, and L. Belec Binding of LFA-1 (CD11a) to Intercellular Adhesion Molecule 3 (ICAM-3; CD50) and ICAM-2 (CD102) Triggers Transmigration of Human Immunodeficiency Virus Type 1-Infected Monocytes through Mucosal Epithelial Cells J. Virol., January 1, 2002; 76(1): 32 - 40. [Abstract] [Full Text] [PDF]
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V. Marechal, M.-C. Prevost, C. Petit, E. Perret, J.-M. Heard, and O. Schwartz Human Immunodeficiency Virus Type 1 Entry into Macrophages Mediated by Macropinocytosis J. Virol., November 15, 2001; 75(22): 11166 - 11177. [Abstract] [Full Text] [PDF]
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) and OV (•), in
the absence of virus (
). The concentration of p24 Ag in pooled
supernatants from triplicate culture wells was assessed by ELISA and
expressed as mean ± SD of four separate experiments
(n = 4; *, p = 0.0001).
B, Number of viral DNA copies in UV or OV infection
cultures was determined 48 h postinfection by quantitative PCR
using HIV-1 MONITOR test. Number of HIV-1 DNA copies/ml was calculated
from (total HIV OD/total internal quantitation standard (pSDL) OD
units) x 30 x 20, in which 30 represents the number of
copies of pSDL added and 20 is the dilution factor.
; *, p < 0.0001) and den-sCD16 (
)
at 2 µg/ml added to cells before and during infection. Viral
production was assessed by ELISA and expressed as mean ± SD
(n = 3). B, The inhibitory effect of
sCD16 on infection of monocytes by OV was dose dependent; cells were
incubated with different concentrations of sCD16 (0.1–2 µg/ml) and
with 2 µg/ml of den-sCD16 before and during infection. Results are
expressed as mean percentage inhibition of infection ± SD of
three independent experiments (n = 3).
). Cells were incubated with anti-CD11b (MO-1) and
anti-CD18 (7E4) (
