Recruitment of leukocytes from blood to tissue in inflammation requires the function of specific cell surface adhesion molecules. The objective of this study was to identify adhesion molecules that are involved in polymorphonuclear leukocyte (PMN) locomotion in extravascular
tissue in vivo. Extravasation and interstitial tissue migration of PMNs was induced in the rat
mesentery by chemotactic stimulation with platelet-activating factor (PAF; 10
7 M). Intravital
time-lapse videomicroscopy was used to analyze migration velocity of the activated PMNs, and
the modulatory influence on locomotion of locally administered antibodies or peptides recognizing various integrin molecules was examined. Immunofluorescence flow cytometry revealed
increased expression of 
4, 
1, and 2 integrins on extravasated PMNs compared with blood
PMNs. Median migration velocity in response to PAF stimulation was 15.5 ± 4.5 µm/min (mean ± SD). Marked reduction (67 ± 7%) in motility was observed after treatment with
mAb blocking 1 integrin function (VLA integrins), whereas there was little, although significant, reduction (22 ± 13%) with 2 integrin mAb. Antibodies or integrin-binding peptides recognizing 41, 51, or v3 were ineffective in modulating migration velocity.
 |
Introduction |
Tissue recruitment of circulating leukocytes is a central
event in the host defense against infectious and noxious agents. The extravasation process comprises a multistep
reaction accomplished through a sequential interaction with
vascular endothelium and extravascular matrix components.
The initial steps in this process, i.e., rolling along the endothelium and firm adhesion, have been extensively studied
both in vitro and in vivo, revealing the function of specific
cell adhesion molecules of the selectin and integrin families
(1). In contrast, the subsequent event of leukocyte migration in the extravascular tissue in response to a chemotactic stimulus is not well characterized, and the receptor interactions involved in this process are largely unknown.
Several cell surface receptors found on leukocytes recognize and bind extracellular matrix (ECM) components. For
example, all known members of the 1 integrin (VLA, very
late activation antigen) family bind to ECM proteins with
varying affinity for specific ECM components, e.g., fibronectin, collagen, and laminin (2). Although 1 integrins
have a widespread distribution, the expression on leukocytes has repeatedly been shown to be largely restricted to
eosinophils, monocytes, and certain lymphocyte subsets, whereas expression on PMNs is limited (2). However, this
view has been reconsidered in recent years because of data
showing that activated or extravasated neutrophils may indeed express certain 1 integrins that potentially can mediate binding to ECM proteins (6).
The 2 integrins (CD11a-c/CD18) are expressed exclusively on leukocytes and mediate firm adhesion to vascular
endothelium (9). Specific ligand binding has been shown for
fibrinogen and factor X of the coagulation cascade, complement factor C3bi, and intercellular adhesion molecule
(ICAM) 1 (1). Moreover, binding of PMNs to a variety of
biological substrates (e.g., fibronectin, collagen) and nonbiological surfaces (such as plastic) has been reported to be 2
dependent, inasmuch as adhesion can be abrogated by
CD11/CD18-blocking antibodies. Yet another member of
the integrin family that has been demonstrated to bind ECM
components and that is expressed in PMNs is the v3 integrin, which binds to vitronectin and fibronectin (10).
The aim of this study was to investigate the role of major
integrin receptors in PMN interstitial migration in vivo. The
potential involvement of the fibronectin-binding integrin receptors in this process was of particular interest because of
their previously documented roles in migration of various cell
types (11). An intravital microscopy model was used for
analyzing leukocyte locomotion in response to local chemotactic stimulation in extravascular tissue of the rat mesentery.
Immunofluorescence flow cytometry revealed increased expression of integrins in extravasated PMNs. This included 1
integrins, which were shown by antibody-blocking experiments to be critically involved in the extravascular PMN migration. However, this process does not seem to engage the
fibronectin-binding receptors 41 and 51.
| |
Materials and Methods |
Surgical Preparation.
Wistar rats of either sex, weighing 200-250
g, were used in the experiments. Anesthesia was induced with equal
parts of fluanison/fentanyl (10/0.2 mg/ml; Hypnorm; Janssen-Cilag
Ltd., Saunderton, UK) and midazolam (5 mg/ml; Dormicum;
Hoffman-La Roche, Basel, Switzerland) diluted 1:1 with sterile water (2 mg/kg intramuscularly). Body temperature was maintained at
37°C by a heating pad connected to a rectal thermistor. Laparotomy
was performed, and a segment of the ileum was pulled outside the
peritoneal cavity and placed on a heated transparent pedestal to allow microscopic observation of the mesenteric microvasculature.
The exposed tissue was superfused with a warmed (37°C) bicarbonate buffer solution equilibrated with 5% CO2 in N2 to maintain
physiological pH. The experiments were approved by the regional
ethical committee for animal experimentation.
Intravital Microscopy.
The exposed rat mesentery was observed
through a microscope (Orthoplan; Leitz, Wetzler, Germany)
equipped with a water immersion lens (SW × 25, NA 0.60; Leitz).
The microscopic image was televised (WV 1050 E/C; Panasonic,
Osaka, Japan) and recorded on time lapse video (AG-6010; Panasonic) connected to a time/date generator (WJ-810; Panasonic).
Recordings were made at one-seventh normal speed. Analysis of
leukocyte migration in the mesenteric tissue was made off-line
from the recorded video scenes during playback at normal speed.
The migration path of individual leukocytes was drawn on a transparent film placed in front of the monitor for subsequent analysis
with a digital image analyzer.
Experimental Procedure.
After positioning under the microscope, the exposed mesentery was soaked with 5 ml of buffer solution (37°C) containing platelet-activating factor (PAF; Sigma
Chemical Co., St. Louis, MO) at a concentration of 107 M. The
tissue was then covered with a transparent plastic film to provide
continuous chemotactic stimulation by PAF. The top of the plastic film was continuously bathed with buffer to maintain temperature at 37°C. After 40 min of chemotactic stimulation, when
numerous leukocytes had extravasated, time-lapse recording of
leukocyte migration was undertaken, first for 20 min to assess basal migration rates in response to PAF stimulation and then for
an additional 40 min in the presence of PAF and antibodies or
peptides administered to the tissue at a concentration of 100 µg/
ml and 500 mM, respectively. A total of five different fields were
analyzed from each animal. In each field, a minimum of five cells
were selected at random and followed as long as they remained within the field of observation (at least 2 min). Cells that did not
move during the observation time were not included in the analysis.
Antibody Diffusion in the Mesentery.
In separate experiments, the
diffusion capability of the Ig molecules in the mesentery was confirmed. Pieces of intact mesenteric tissue (thickness: 20-40 µm)
were mounted on plastic rings and placed on top of HBSS-filled
wells (400 µl/well) of a 96-well tissue culture plate. 40 µl of
FITC-conjugated murine IgG (100 µg/ml) were placed on the
surface of the mesentery. The plate was incubated at 37°C for 10 min, and the fluorescence intensity of the IgG content in the upper and lower fluid compartments was measured in a fluorometer
(Fluoroscan II; Labsystems Oy, Helsinki, Finland). Over a period
of 10 min, an average of 7.5 ± 1.6% of applied antibody diffused
through the mesentery per minute and cm2 (n = 3), indicating
that there is no significant restriction for diffusion of the antibodies into the mesenteric tissue when being topically administered.
Staining of Leukocytes.
Representative samples of the mesentery stimulated with PAF 107 M for 1.5 h were stained with
Wright/Giemsa (Sigma Chemical Co.) for 10 min in stock concentration and in dilution 1:1 with water for another 10 min at
room temperature. Leukocytes in peripheral blood and in peritoneal fluid collected after 1.5 h PAF stimulation were similarly
stained. After a thorough rinse of the specimens in HBSS, a differential leukocyte count was made with an ×100 oil-immersion
objective. In addition to the Wright/Giemsa stain, leukocytes in
the mesenteric tissue were stained by brief exposure to acridine
orange (2.5 mg/ml; Sigma Chemical Co.) and viewed under fluorescent light to improve discrimination of nuclear morphology. Percentage of leukocyte count based on analysis of at least 50 leukocytes in each of 5-7 microscopic fields in each preparation is
given in Table 1 (mean values of data from 3 animals). In another
set of experiments, PAF-stimulated mesenteric tissue was incubated with antibodies against the 1, 4, or 2 integrin subunit for
30 min at 37°C. After washing, the tissue was incubated with FITC- or TRITC-conjugated F(ab)2 fragments of anti-mouse or
-hamster IgG (diluted 1:50) at room temperature for 30 min. The
tissue was again washed and fixed for 15 min in 4% paraformaldehyde. The tissue specimens were observed in normal transmitted
light and with fluorescent epiillumination (filter block I2 and M2; Leitz Ploemopak). Specificity of antibody binding was confirmed by comparing the immunofluorescence obtained with specific
primary mAb with that of isotype-matched irrelevant mAb at the
same concentration and incubation time.
Immunofluorescence Flow Cytometric Analysis.
Leukocytes collected
from rats of the same strain and weight as used in the in vivo experiments were used for analysis of integrin receptor expression. Leukocyte extravasation was induced by intraperitoneal injection of either 3% proteose peptone (Sigma Chemical Co.) or PAF 107 M
in 10 ml HBSS. After 2 h, the animals were killed with methyl-ether and peritoneal leukocytes were harvested by washing the
peritoneal cavity with 10 ml ice-cold HBSS. EDTA-anticoagulated
blood was collected from the same animal, and leukocyte-rich
plasma was obtained through dextran sedimentation. Blood and
peritoneal leukocytes were washed twice at 150 g for 7 min at 4°C
and resuspended in HBSS at a final concentration of 106 cells/ml.
The leukocyte suspension was incubated with primary antibodies
(10 µg/ml) or isotype-matched control antibodies for 20 min at
4°C and washed twice. FITC-conjugated F(ab)2 fragments of rabbit
anti-mouse IgG (Dako, Glostrup, Denmark), donkey anti-rabbit IgG (Jackson Immunoresearch, West Grove, PA), and goat anti-
hamster IgG (Jackson Immunoresearch) diluted 1:20 were used as
second antibodies. After staining (20 min, 4°C), the cells were fixed (1% formaldehyde, FACS® Lysing Solution [Becton Dickinson,
Mountain View, CA]), washed twice, and analyzed on a FACSort®
flow cytometer (Becton Dickinson). The fluorescence intensity of
104 PMNs (>95% neutrophils; see Table 1) was analyzed by selective gating based on forward and side scatter parameters.
Antibodies and Peptides.
The following antibodies were used:
mAb HM1-1 (PharMingen, San Diego, CA) and purified IgG
from a rabbit antiserum (gift of K. Rubin, Uppsala, Sweden)
against the rat 1 chain (CD29); mAbs CL26 (Upjohn, Kalamazoo, MI) and WT.3 (PharMingen), recognizing the rat 2 chain
(CD18); mAbs MR4 (PharMingen) and TA-2 (Serotec, Oxford, UK), which react with the rat integrin 4 subunit (CD49d); mAb HM5-1 against the rat 5 (CD49e) (PharMingen); and a
rabbit antiserum against human v3 (CD51/CD61) (14). Function-blocking activity in rat systems has been documented for all
antibodies used in this study. All antibody solutions were free of
preservatives except MR4 and HM5-1, which contained 0.1%
sodium azide. Control experiments showed that sodium azide in
corresponding concentration did not influence cell locomotion.
The integrin-binding peptides SLIDIP and ACRGDGWMCG
(RGDGW), capable of functionally blocking 41 and 51 (15),
were also used.
Statistical Analysis.
Statistical analysis was performed using the
Wilcoxon signed rank test for paired observations. The results are
presented as mean ± SD for the animals included in each experimental group (n 
5 unless otherwise stated).
| |
Results |
1-Integrin Cell Surface Expression Is Associated with PMN
Extravasation.
Flow cytometric assessment of cell surface
molecule expression on neutrophils that had extravasated
into the peritoneal cavity revealed positive staining for 1
(CD29) and 4 (CD49d) integrin molecules (Fig. 1 and
Table 2). This pattern contrasted to that of blood PMNs
where little or no staining for 1 and 4 was seen (Fig. 1),
indicating that cell surface expression of 1 integrins is induced in conjunction with the extravasation process. Expression of 5 (CD49e) was limited in both cell populations. There was an increased expression of 2 integrins
(CD18) on extravasated PMNs compared to their blood
counterpart, whereas staining for v3 (CD51/CD61) was
similarly positive in both PMN populations (Table 2).
View larger version (25K):
[in this window]
[in a new window]
|
Fig. 1.
Immunofluorescent
staining of integrins on blood
PMNs (thin line) and on extravasated PMNs collected from the
peritoneal cavity (thick line). Thin
vertical line indicates the 99th
percentile of fluorescence events
for cells stained with isotype
matched control antibody. Histograms are representative tracings of three to five analyses for
each antibody.
|
|
Preincubation of isolated blood PMNs with PAF (107
M) before antibody labeling did not result in 1 or 4 integrin expression dissimilar from that of untreated blood cells
(data not shown).
PMN Migration In Vivo Is Dependent on 1 Integrins.
Topical stimulation of the rat mesentery with PAF (107
M) induced profound adhesion and extravasation of circulating leukocytes. At 30-40 min of chemotactic stimulation, numerous leukocytes (predominantly neutrophils, see
Table 1) were migrating further in the extravascular tissue
(Fig. 2 A). In accordance with the flow cytometric data, immunofluorescent staining of emigrated PMNs in the mesenteric tissue in situ showed surface expression of 1, 4,
and 2 integrin molecules, as illustrated for 4 in Fig. 2 B.
View larger version (76K):
[in this window]
[in a new window]
|
Fig. 2.
Micrographs showing migrating PMNs in a tissue section of
the rat mesentery after stimulation with PAF (107 M) for 40 min (A),
and immunofluorescent staining for 4 integrins in the same cells (B). The
fluorescence is concentrated and localized to spots in most PMNs, indicating a polarized integrin expression (arrows), whereas in some cells a
more scattered distribution is seen. Bar: 10 µm.
|
|
Fig. 3 A illustrates the frequency distribution of the migration velocity of individual PMNs in response to stimulation with PAF (649 cells in 30 animals total). Among these
cells, the median migration velocity was 15.5 ± 4.5 µm/min
(mean ± SD). The migration velocity was stable over a period of >1.5 h after induction of the chemotactic stimulus.
The role of various integrins in PMN migration was evaluated by topical administration of antibodies to the tissue.
Treatment with anti-1 (mAb HM1-1) resulted in a pronounced inhibition of PMN locomotion. Migration velocity was reduced by 67 ± 7% (P <0.01; Fig. 4), yielding
a median migration velocity of 4.6 ± 1.3 µm/min (Fig. 3
B). Notably, as evident from Fig. 3 B, the whole population of migrating cells, rather than a certain fraction, was
affected by this antibody treatment. A less pronounced effect was observed with the polyclonal anti-1 antibody,
which reduced the migration velocity by 32 ± 15% (P <0.01; Fig. 4). No further inhibition was achieved when
the antibody concentration was increased 10-fold. Treatment with two different antibodies against the 2 chain
(CD18) also significantly reduced migration velocity, by 17 ± 14% (mAb CL26) and 22 ± 13% (mAb WT.3) (P
<0.05; Fig. 4). An additive inhibitory effect was observed when anti-2 mAb was administered together with the
polyclonal anti-1 serum. This combined treatment reduced
migration velocity by 52 ± 18% (P <0.01; Fig. 4). On the
other hand, coadministration of anti-2 mAb with the anti-1
mAb HM1-1 yielded no further inhibition of migration
velocity above that seen with HM1-1 alone. The inhibitory effect of the various antibody treatments was observed within minutes after application and persisted throughout the observation period (>40 min) as shown for mAb HM1-1
(Fig. 5). Purified hamster, mouse, and rabbit IgG isotype
standards did not influence migration velocity (103 ± 11, 95 ± 7, and 99 ± 8%, respectively).
View larger version (30K):
[in this window]
[in a new window]
|
Fig. 3.
Frequency distribution of PMN migration velocity
in extravascular tissue of the rat
mesentery in response to chemotactic stimulation with PAF
(107 M). (A) Migration velocities during control period (PAF
alone). (B) Migration velocities
after topical treatment with the
anti-1 mAb HM1-1.
|
|
View larger version (28K):
[in this window]
[in a new window]
|
Fig. 4.
Effect of local treatment with various integrin antibodies and
integrin-binding peptides on PMN migration velocity in the rat mesentery stimulated with PAF (107 M). Data are expressed as percent of migration velocity before treatment, and represent mean ± SD of five experiments for each reagent tested. Asterisk, denotes significant difference
from control (P <0.05).
|
|
View larger version (16K):
[in this window]
[in a new window]
|
Fig. 5.
Time course of inhibitory effect of the anti-1 mAb
HM1-1 on PMN migration
velocity in the rat mesentery ( )
compared with control antibody
( ). Data are based on calculation of mean migration velocity
during defined 10 or 20 min intervals, and presented as means ± SD of five separate experiments for each antibody. Note that the inhibitory effect on PMN locomotion persisted throughout the observation period.
|
|
Despite pronounced upregulation of the integrin 4 subunit (CD49d) on extravasated PMNs, no significant modulatory effect on the migration velocity was observed after
treatment with either of the two anti-4 mAbs. Antibodies
against 51 or v3 also did not influence PMN locomotion. Moreover, combined treatment with anti-2 mAb together with either anti-4 or anti-4 plus anti-5 mAb resulted in no further inhibition of migration velocity above
that obtained with anti-2 treatment alone (99 ± 4 and 95 ± 10%, respectively, n = 3). The integrin-binding peptides
SLIDIP and RGDGW, which mimic natural ligand binding and block the function of 41 and 51, respectively,
also had no effect on the migration velocity either in combination (data not shown) or alone (Fig. 4). There was no
difference in the effect for any of the reagents tested when
concentration was raised 10 times (data not shown).
| |
Discussion |
Extravasation and tissue accumulation of leukocytes is
one of the key components in the host defense against invading pathogens. After their escape from the blood, the
leukocytes need to migrate in the extravascular tissue, directed by a chemotactic stimulus, to reach the site of injury
or infection. Studies of leukocyte migration in vitro have
indicated the interaction of leukocytic cell surface receptors
with different extracellular matrix components in this process (16). However, interactions with the multitudinous meshwork of biopolymers that characterizes native extracellular matrix and the function in vivo of leukocyte integrins
in the locomotive process have yet to be defined. In this report, we demonstrate that 1 integrins, induced in PMNs in
conjunction with their extravasation, are of critical functional importance for PMN locomotion in extravascular tissue. Our data on a physiological induction of 1 integrin
expression in PMNs agree with recent in vitro and in vivo
findings by Kubes and coworkers (7, 8), and contribute to a
growing body of evidence that 1 integrin expression may
reach significant levels also in neutrophils (6, 17, 18). Also,
the upregulation of 2 integrins on extravasated PMNs is
consistent with the activation-induced upregulation of 2
integrins on the leukocyte surface (19) and the critical role
of this receptor complex in leukocyte adhesion to endothelium and diapedesis through the vessel wall in vivo (20).
A qualitatively similar pattern of PMN 1 integrin expression as obtained with flow cytometric analysis of extravasated PMNs isolated from the peritoneal cavity could
be demonstrated by in situ immunostaining of PMNs migrating in the extravascular tissue of the mesentery. These
findings are also of significance from a methodological
point of view, since they illustrate that antibodies applied
topically to the mesentery indeed do diffuse into the tissue,
and by this route of administration will reach the migrating PMNs (see Materials and Methods). Thus, we may conclude that adequate antibody concentrations were achieved
in the tissue at the level of the migrating cells (no additional
effect was seen when antibody concentration was raised 10 times), and that restrictions in antibody transport could not
account for the lack of effect of some of the reagents used.
Our quantitative measurements of PMN migration in
the rat mesentery in vivo show that 1 and 2 integrins participate in extravascular PMN locomotion, and that they
may cooperate in this process. Blockage of 1 and 2 integrin function impaired the ability of the leukocytes to migrate in the extravascular tissue as indicated by significant reductions in their migration velocity. Anti-1 antibodies
were clearly more effective in inhibiting PMN migration
than were anti-2, suggesting a predominant role of 1 integrins in the locomotive process in vivo. The additive inhibitory effect observed when anti-2 mAb was coadministered with the polyclonal anti-1 antiserum but not when
combined with the anti-1 mAb may suggest that a synergistic action of combined anti-1 and anti-2 treatment is detectable only when 1 integrins are insufficiently blocked
(as was likely the case when the polyclonal anti-1 antibody
was used). In contrast to our findings with 2 integrin
blockade, Bienvenu et al. (21), using a similar rat model,
found no inhibition of the extravascular migration with
anti-2 treatment. Differences in the experimental protocol
(e.g., the antibody concentration used) may explain the discrepant observations. Also, although statistically significant,
the inhibition we found with anti-2 was limited and may
have been overlooked by these authors.
Although it has been shown for certain leukocyte subtypes that migration on various ECM matrices in vitro requires the function of specific integrin molecules (16, 22),
this report is the first to demonstrate an in vivo role for 1
integrins in the extravascular locomotion of leukocytes.
Even if it can not be deduced which 1 integrins are predominantly involved in the PMN locomotion, our data
suggest, based on use of both monoclonal function-blocking antibodies and integrin-binding peptides, that the fibronectin binding receptors 41 and 51 do not participate in this process. This finding may seem surprising in
light of the pronounced upregulation of 4 integrins on extravasated PMNs, and the central position being attributed
to fibronectin in various aspects of cell migration (11, 12).
Previous findings have suggested a role for 41 and 51
in migration of PMN from blood to tissue sites in vivo (17)
or through fibroblast monolayers in vitro (18), seemingly in
disparity with our direct observations in the rat mesentery. Possibly, mAb inhibition of integrin function in these studies interfered mainly with initial adhesion to endothelium
or the fibroblast monolayer and less with the locomotive
function. Interestingly, through direct observation of leukocyte migration in three-dimensional gels, an enhanced
lymphocyte migration after anti-4 mAb treatment (16), and
reduced PMN locomotion after the gel being supplemented with fibronectin was demonstrated (23). These findings may
suggest that fibronectin-binding integrins (e.g., 41 and
51) may support anchoring of the leukocytes to the substrate rather than promote their migratory movement.
Taken together, expression of 1 integrins, limited on
blood PMNs, is induced in this cell population in conjunction with their emigration from blood to tissue. Our data
demonstrate that molecules of this integrin family are critically involved in PMN locomotion in extravascular tissue
in vivo. Hence, in addition to selectin and 2 integrin
functions determining intravascular adhesive events, cell
surface induction and engagement of 1 integrins is suggested to be yet another important physiological mechanism in the multistep process of PMN recruitment to sites
of injury or infection.
Address correspondence to Lennart Lindbom, Department of Physiology and Pharmacology, Karolinska Institutet,
S-171 77 Stockholm, Sweden. Phone: 46-8-728-7207; Fax: 46-8-332-047; E-mail: lennart.lindbom{at}fyfa.ki.se
This study was supported by the Swedish Medical Research Council (grants 14X-4342 and 04P-10738); the
Swedish Foundation for Health Care Sciences and Allergy Research (grant A98110); the IngaBritt and Arne
Lundbergs Foundation; and the Karolinska Institutet. E. Ruoslahti was a Nobel Fellow at the Karolinska Institutet when this work was initiated.
| 1.
|
Carlos, T.M., and
J.M. Harlan.
1994.
Leukocyte-endothelial
adhesion molecules.
Blood.
84:
2068-2101
[Abstract/Free Full Text].
|
| 2.
|
Hemler, M.E..
1990.
VLA proteins in the integrin family:
structures, functions, and their role on leukocytes.
Annu. Rev.
Immunol.
8:
365-400
[Medline].
|
| 3.
|
Ignatius, M.J.,
T.H. Large,
M. Houde,
J.W. Tawil,
A. Barton,
F. Esch,
S. Carbonetto, and
L.F. Reichardt.
1990.
Molecular cloning of the rat integrin alpha 1-subunit: a receptor
for laminin and collagen.
J. Cell Biol.
111:
709-720
[Abstract/Free Full Text].
|
| 4.
|
Wayner, E.A., and
W.G. Carter.
1987.
Identification of multiple cell adhesion receptors for collagen and fibronectin in
human fibrosarcoma cells possessing unique alpha and common beta subunits.
J. Cell Biol.
105:
1873-1884
[Abstract/Free Full Text].
|
| 5.
|
Gehlsen, K.R.,
L. Dillner,
E. Engvall, and
E. Ruoslahti.
1988.
The human laminin receptor is a member of the integrin family of cell adhesion receptors.
Science.
241:
1228-1229
[Abstract/Free Full Text].
|
| 6.
|
Bohnsack, J.F., and
X.N. Zhou.
1992.
Divalent cation substitution reveals CD18- and very late antigen-dependent pathways that mediate human neutrophil adherence to fibronectin.
J. Immunol.
149:
1340-1347
[Abstract].
|
| 7.
|
Kubes, P.,
X.F. Niu,
C.W. Smith,
M.E. Kehrli Jr.,
P.H. Reinhardt, and
R.C. Woodman.
1995.
A novel beta 1-dependent
adhesion pathway on neutrophils: a mechanism invoked by dihydrocytochalasin B or endothelial transmigration.
FASEB J.
9:
1103-1111
[Abstract].
|
| 8.
|
Reinhardt, P.H.,
C.A. Ward,
W.R. Giles, and
P. Kubes.
1997.
Emigrated rat neutrophils adhere to cardiac myocytes
via 4 integrin.
Circ. Res.
81:
196-201
[Abstract/Free Full Text].
|
| 9.
|
Springer, T.A..
1990.
Adhesion receptors of the immune system.
Nature.
346:
425-434
[Medline].
|
| 10.
|
Pytela, R.,
M.D. Pierschbacher, and
E. Ruoslahti.
1985.
Identification and isolation of a 140 kd cell surface glycoprotein with
properties expected of a fibronectin receptor.
Cell.
40:
191-198
[Medline].
|
| 11.
|
Ruoslahti, E..
1991.
Integrins.
J. Clin. Invest.
87:
1-5
.
|
| 12.
|
Bauer, J.S.,
C.L. Schreiner,
F.G. Giancotti,
E. Ruoslahti, and
R.L. Juliano.
1992.
Motility of fibronectin receptor-deficient
cells on fibronectin and vitronectin: collaborative interactions
among integrins.
J. Cell Biol.
116:
477-487
[Abstract/Free Full Text].
|
| 13.
| Aota, S., and K.M. Yamada. 1995. Fibronectin and cell adhesion: specificity of integrin-ligand interaction. In Advances in
Enzymology and Related Areas of Molecular Biology. A. Meister, editor. Vol. 70. pp. 1-21.
|
| 14.
|
Suzuki, S.,
W.S. Argraves,
R. Pytela,
H. Arai,
T. Krusius,
M.D. Pierschbacher, and
E. Ruoslahti.
1986.
cDNA and
amino acid sequences of the cell adhesion protein receptor
recognizing vitronectin reveal a transmembrane domain and
homologies with other adhesion protein receptors.
Proc. Natl.
Acad. Sci. USA.
83:
8614-8618
[Abstract/Free Full Text].
|
| 15.
|
Koivunen, E.,
D.A. Gay, and
E. Ruoslahti.
1993.
Selection
of peptides binding to the alpha 5 beta 1 integrin from phage
display library.
J. Biol. Chem.
268:
20205-20210
[Abstract/Free Full Text].
|
| 16.
|
Friedl, P.,
P.B. Noble, and
K.S. Zänker.
1993.
Lymphocyte
locomotion in three-dimensional collagen gels. Comparison
of three quantitative methods for analysing cell trajectories.
J.
Immunol. Methods.
165:
157-165
[Medline].
|
| 17.
|
Issekutz, T.B.,
M. Miyasaka, and
A.C. Issekutz.
1996.
Rat
blood neutrophils express very late antigen 4 and it mediates
migration to arthritic joint and dermal inflammation.
J. Exp.
Med.
183:
2175-2184
[Abstract/Free Full Text].
|
| 18.
|
Gao, J.X., and
A.C. Issekutz.
1997.
The beta 1 integrin, very
late activation antigen-4 on human neutrophils can contribute to neutrophil migration through connective tissue fibroblast barriers.
Immunology.
90:
448-454
[Medline].
|
| 19.
|
Neeley, S.P.,
K.J. Hamann,
S.R. White,
S.L. Baranowski,
R.A. Burch, and
A.R. Leff.
1993.
Selective regulation of expression of surface adhesion molecules Mac-1, L-selectin, and
VLA-4 on human eosinophils and neutrophils.
Am. J. Respir.
Cell Mol. Biol.
8:
633-639
.
|
| 20.
|
Arfors, K.E.,
C. Lundberg,
L. Lindbom,
K. Lundberg,
P.G. Beatty, and
J.M. Harlan.
1987.
A monoclonal antibody to the
membrane glycoprotein complex CD18 inhibits polymorphonuclear leukocyte accumulation and plasma leakage in
vivo.
Blood.
69:
338-340
[Abstract/Free Full Text].
|
| 21.
|
Bienvenu, K.,
N. Harris, and
D.N. Granger.
1994.
Modulation of leukocyte migration in mesenteric interstitium.
Am. J. Physiol.
267:
H1573-H1577
[Abstract/Free Full Text].
|
| 22.
|
Lawson, M.A., and
F.R. Maxfield.
1995.
Ca(2+)- and calcineurin-dependent recycling of an integrin to the front of
migrating neutrophils.
Nature.
377:
75-79
[Medline].
|
| 23.
|
Kuntz, R.M., and
W.M. Saltzman.
1997.
Neutrophil motility in extracellular matrix gels: mesh size and adhesion affect
speed of migration.
Biophys. J.
72:
1472-1480
[Abstract/Free Full Text].
|
1 Integrins Are Critically Involved in Neutrophil
Locomotion in Extravascular Tissue In Vivo
Top
Abstract
Introduction
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
