| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
*
Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109; and
Department of Medical Microbiology and Immunology, University of California School of Medicine, Davis, CA 95616
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The rigorous characterization of >50 strains of N. asteroides has greatly facilitated the study of bacterial-host interactions (reviewed in Ref. 2). Virulent strains of N. asteroides have evolved unique mechanisms of evading host macrophage-mediated killing. Specifically, virulent strains can inhibit phagosome-lysosome fusion, decrease lysosomal enzyme activity, and neutralize phagosomal acidification (3, 4, 5, 6, 7). These evasive mechanisms result in the ability of the organism to grow intracellularly within alveolar macrophages. During experimental pulmonary nocardiosis, the inflammatory response is predominantly neutrophilic, subsequently replaced by a mononuclear infiltration by day 7. However, the precise role of neutrophils during infection is unresolved. In vitro data indicate that neutrophils and monocytes only marginally kill phagocytized N. asteroides (8, 9, 10, 11). In contrast, in vivo depletion of neutrophils using a polyclonal anti-neutrophil Ab or monocytes using silica resulted in increased nocardial burden (12, 13).
Chemokines are a growing collection of chemotactic cytokines divided into four families (14). The CXC chemokine family can be further subdivided based on the presence or absence of a three-amino acid motif termed ELR (glutamic acid-leucine-arginine). ELR+ CXC chemokines, including IL-8, epithelial neutrophil-activating protein-78, macrophage inflammatory protein-2 (MIP-2),3 and KC, have potent neutrophil chemotactic activity (15, 16, 17). Two receptors for ELR+ CXC chemokines have been identified in humans, CXC chemokine receptor-1 and -2 (CXCR1 and CXCR2) (18, 19). Murine CXCR2, like its human counterpart, binds all ELR+ CXC chemokines (20, 21, 22, 23). Interestingly, mice lack expression of CXCR1 (20). These receptors, like all chemokine receptors identified to date, are seven-transmembrane spanning, G-protein-coupled receptors. Neutrophils from CXCR2 knockout mice fail to migrate in response to MIP-2 and KC in vitro (24), confirming the exclusive utilization by CXC chemokines of this receptor on neutrophils.
Here, we detail the dependence of CXCR2 ligand-mediated neutrophil recruitment for effective host defense in pulmonary infections due to N. asteroides. These data directly link CXCR2-binding chemokines and neutrophil recruitment during N. asteroides pulmonary infection and indicate a critical role for neutrophils and CXC chemokines during the initial phases of pulmonary nocardiosis.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Female BALB/c mice were purchased from The Jackson Laboratory (Bar Harbor, ME). Mice were used between the ages of 5–8 wk, being age-matched within a given experiment. All mice were housed under specific pathogen-free condition within the animal care facility at the University of Michigan.
N. asteroides growth and intratracheal inoculation
N. asteroides strain GUH-2 was originally isolated from a fatal kidney infection in a renal transplant patient. It is a highly virulent strain of Nocardia with growth characteristics that have been well documented (25, 26, 27). Briefly, brain heart infusion (BHI) broth (Difco, Detroit, MI) starter cultures were inoculated from late stationary phase frozen stocks. Cultures were grown for 4–6 days on an orbital shaker at 37°C. Overnight cultures were then inoculated by transferring 10–30 µl of a late stationary phase starter culture into 50 ml BHI broth and shaken for 16–18 h. The bacterial concentration of early to mid-log phase cultures was then determined by measuring absorbance at 580 nm and compared with a predetermined standard curve. The filamentous, branching morphology characteristic of log phase growth was confirmed for each culture by Gram stain (Difco). Bacteria were then diluted to the desired concentration for intratracheal inoculation. BALB/c mice were anesthetized with pentobarbital (diluted 1:7 in saline). The trachea was exposed, and 30 µl inoculum or saline administered via a sterile 26-gauge needle. An aliquot of the inoculated nocardial suspension was serially diluted onto blood agar plates to determine actual dose of intratracheally injected bacteria.
In vivo Ab administration
Neutrophils were depleted in vivo utilizing the pan-granulocytic Ab RB6-8C5 (28), directed against Ly-6G. Anti-Ly-6G was produced as an ascites in SCID mice by TSD BioServices (Germantown, NY) and used at a dilution determined to deplete both peripheral blood and resident lung neutrophils. The Ab was injected in a 0.5-ml volume i.p. 18 h before nocardial infection and again 1 day postinfection. This treatment scheme has been used to deplete neutrophils in vivo in a variety of bacterial and fungal models (29, 30, 31). Reagent control animals for anti-Ly-6G received normal mouse serum at the same dilution used for anti-Ly-6G treatment. Polyclonal Ab directed against the murine CXCR2 chemokine receptor was produced by immunizing goats with a peptide containing the ligand-binding sequence Met-Gly-Glu-Phe-Lys-Val-Asp-Lys-Phe-Asn-Ile-Glu-Asp-Phe-Phe-Ser-Gly. This protein sequence has been shown to contain the ligand-binding portion of the CXCR2 receptor (32). Anti-CXCR2 administration did not alter the number of circulating neutrophils in BALB/c mice. Additionally, i.p. injection of anti-CXCR2 Ab abrogated neutrophil recruitment into the peritoneum in response to exogenous KC (data not shown) and prevented neutrophil recruitment in a murine model of pulmonary aspergillosis (33). In CXCR2 receptor blockade experiments, mice were injected i.p. with 0.5 ml goat anti-mouse CXCR2 Ab 2 h before nocardial infection. For studies extending beyond 1 day postinfection, mice received another dose of Ab 36 h postinfection. Mice were treated with rabbit anti-mouse MIP-2 Ab in a manner similar to that for anti-CXCR2 treatment. Depletion of MIP-2 was confirmed by ELISA. Control mice in anti-CXCR2 experiments received normal goat serum, and control mice in anti-MIP-2 experiments received normal rabbit serum i.p. In our hands, infected mice receiving control reagents for anti-Ly-6G, anti-CXCR2, and anti-MIP-2 had no detrimental effects when compared with infected animals alone.
Whole lung homogenization for CFU, myeloperoxidase (MPO), and cytokine analysis
At designated time points, the mice were euthanized by inhalation of CO2. The lungs were perfused with 1 ml PBS, 5 mM EDTA and removed for analyses as previously described (34). Briefly, lungs were homogenized with a tissue homogenizer (Biospec Products, Bartlesville, OK) in 1 ml PBS-complete protease inhibitor mixture (Boehringer Mannheim Biochemical, Chicago, IL). For lung CFU determination, a small aliquot of lung homogenate was serially diluted and plated on blood agar plates and incubated at 37°C, and colonies were counted.
Lung MPO activity, as an indirect measurement of total neutrophil numbers, was quantitated by a method described previously (34). Briefly, 100 µl lung homogenate were mixed with 100 µl MPO homogenization buffer (0.5% hexadecyltrimethylammonium bromide and 5 mM EDTA) and vortexed. The mixture was sonicated and centrifuged at 12,000 x g for 15 min. The supernatant was then mixed 1:15 with assay buffer and read at 490 nm. MPO units were calculated as the change in absorbance over time.
For total lung cytokine ELISA analyses, lung homogenates were sonicated briefly to ensure complete cellular disruption, then centrifuged at 2500 rpm for 10 min. The supernatants were collected and assessed for cytokine levels by ELISA. Murine MIP-2 and KC were quantitated by a modification of a sandwich ELISA method. This methodology allows detection of MIP-2 and KC at concentrations of 20 pg/ml and higher. Additionally, assays have been shown to be specific for the indicated murine chemokine and show no cross-reactivity with any other murine cytokines tested (34).
Total lung leukocyte preparation
Total lung leukocytes were isolated from N. asteroides-infected mice on day 1 postinfection. Lungs were removed from euthanized animals, and leukocytes were prepared as previously described (35). Briefly, lungs were minced with scissors to a fine slurry in 15 ml lung digestion buffer (RPMI, 5% FCS, 1 mg/ml collagenase (Boehringer Mannheim Biochemical), 30 µg/ml DNase (Sigma, St. Louis, MO)). Lung slurries were enzymatically digested for 30 min at 37°C. Any undigested fragments were further dispersed by drawing the solution up and down through the bore of a 10-ml syringe. The total lung cell suspension was pelleted, resuspended, and spun through a 20% Percoll gradient to enrich for leukocytes before further analysis. Cell counts and viability were determined by trypan blue exclusion counting on a hemacytometer. Cytospin slides were prepared and stained with a modified Wright-Giemsa stain to determine percent and total lung neutrophil numbers.
Tissue harvesting for histological examination
Lungs for histochemistry were perfused with 4% paraformaldehyde in PBS, then inflated with 4% paraformaldehyde to improve resolution of anatomic relationships, and excised at the hilum. Lung sections were then stained with hematoxylin and eosin (H&E) to determine inflammatory responses during infection and Gomori methenamine-silver (GMS) to determine the presence of N. asteroides.
Statistical analysis
Statistical significance was determined using the unpaired, two-tailed alternate Welsh t test and the nonparametric Mann-Whitney test. Calculations were performed using InStat For Macintosh (GraphPad Software, San Diego, CA).
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Murine nocardial pneumonia was induced by the intratracheal
injection of log growth phase cultures of the highly virulent strain
GUH-2 of N. asteroides into BALB/c mice. To determine
susceptibility in our model, various doses of GUH-2 were injected and
animals were observed for signs of illness and mortality. Inoculum
doses of less than 2 x 106 CFU resulted in
clinical signs of illness within one day post infection, which
subsequently resolved without any mortality observed (Fig. 1
). Doses of GUH-2 ranging between
3–4 x 106 CFU induced significant signs of
overt illness within one day which progressively worsened over the next
1–2 days, resulting in significant mortality. Mice surviving the first
3–4 days of infection went on to survive long-term with no overt signs
of illness.
|
Pulmonary neutrophil recruitment during N. asteroides
infection was examined by measuring total lung MPO activity over time.
Lung MPO activity reached maximal levels within 1 day of infection,
with elevated activity persisting through day 3 before returning to
near baseline levels by day 7 (Fig. 2).
|
). A rapid inflammatory response
consisting predominantly of neutrophils could be seen as early as day
1. Lungs exhibited signs of perivascular inflammation with distinct
sites of bronchopneumonia containing neutrophils and proteinaceous
exudates. By day 3, the inflammatory sites had become more
consolidated, although still containing mainly neutrophils. Mononuclear
cells replaced this early neutrophilic infiltration by day 7. A GMS
stain determined the presence of N. asteroides in histology
sections. Abundant branching, filamentous Nocardia were
observed predominantly in active sites of inflammation within the lumen
of distal airways 1 day after inoculation with GUH-2. Branching
Nocardia organisms were still observed on day 3, although
fewer in number. By day 7, few Nocardia were seen, in
agreement with the paucity of recoverable CFU at this time point
(
0.5% of the total inoculated dose of N. asteroides,
data not shown).
|
The rapid increase in lung MPO activity suggested an important
role for neutrophils in the resolution of N. asteroides
pulmonary infection. To test this hypothesis, mice were depleted of
neutrophils in vivo before intratracheal GUH-2 inoculation utilizing a
mAb directed against the pan-granulocytic marker Ly-6G. Mice depleted
of their neutrophils before infection required 100-fold fewer
inoculated N. asteroides bacteria to achieve an equivalent
lethal dose seen in non-neutrophil-depleted mice (Fig. 4, LD20, 3 x
104 CFU in neutrophil-depleted animals vs 3
x 106 in control mice).
|
Data thus far indicated a vigorous and rapid host response to
nocardial pulmonary challenge, resulting in a neutrophil dominant
inflammatory response. Given that ELR+ chemokines
exhibit potent neutrophil chemotactic activity in vitro and in vivo,
production of the murine ELR+ chemokines MIP-2
and KC was determined in lung homogenates after N.
asteroides challenge (Table I).
MIP-2 production was rapidly up-regulated within 24 h after
nocardial challenge, with levels increasing through day 3 followed by a
significant reduction by day 7 postchallenge. KC secretion was also
rapidly induced within 24 h. Unlike MIP-2 production, KC levels
increased only slightly by day 3, followed by a rapid decrease by day
7. The return to near baseline levels of both MIP-2 and KC by day 7
after infection is in concordance with both the reduction in lung MPO
activity and histological examination, indicating the replacement of
neutrophils within the sites of inflammation with mononuclear
cells.
|
The rapid and sustained production of high levels of MIP-2 suggested that this chemokine may be an important component in neutrophil recruitment during N. asteroides infection. To test this hypothesis, mice were treated with an anti-MIP-2 Ab capable of inhibiting the bioactivity of MIP-2 in vivo (17). Interestingly, inhibition of MIP-2 activity before infection had no detrimental effect on survival after N. asteroides challenge (data not shown). Furthermore, anti-MIP-2 administration had no effect on the total number of pulmonary neutrophils recruited following nocardial infection or on pulmonary bacterial clearance (data not shown).
This anti-MIP-2 data suggested the dependence on alternative or
additional chemokines for neutrophil recruitment during pulmonary
nocardiosis. Examining the role of individual CXC chemokines is
compounded by the overlapping neutrophil chemotactic activity of
numerous members of this family. To study the role of
ELR+ CXC chemokines as an entire family, a
ligand-blocking polyclonal goat anti-mouse CXCR2 Ab was utilized.
This Ab blocks the binding of MIP-2, KC, and other
ELR+ CXC chemokines to the CXCR2 receptor,
thereby inhibiting neutrophil chemotaxis in vitro and in vivo.
Importantly, mice treated with anti-CXCR2 were significantly more
susceptible to nocardial infection (Fig. 5), analogous to that observed after
depletion of neutrophils with anti-Ly-6G.
|
To assess the effect of anti-CXCR2 or anti-Ly-6G treatment
on neutrophil recruitment during N. asteroides infection,
total lung neutrophil numbers were examined after infection and Ab
treatment. Total pulmonary neutrophils were determined by enzymatic
dissociation of lung leukocytes to observe directly any effect on
neutrophil recruitment by either anti-CXCR2 or anti-Ly-6G
treatment. Anti-CXCR2 and anti-Ly-6G treated mice were highly
susceptible to nocardial infection; therefore the inoculum dose of
GUH-2 was reduced to 1–2 x 105 CFU from
2–3 x 106 to ensure mouse survival 24
h postinfection. This decreased dose resulted in 100% mortality in
neutrophil-depleted mice by day 2 while still presenting a significant
challenge to nondepleted mice. Intratracheal challenge with N.
asteroides resulted in a 4-fold increase in total lung neutrophil
numbers 1 day postinfection (Fig. 6).
Anti-CXCR2 treatment did not decrease the baseline number of lung
neutrophils below that of mice challenged with intratracheal saline.
However, pretreatment of mice with anti-CXCR2 Ab prevented
neutrophil recruitment into the lung after bacterial challenge. In
contrast, mice treated with anti-Ly-6G followed by bacterial
challenge had a dramatic decrease in total lung neutrophils compared
with saline administration or after GUH-2 infection.
|
). Filamentous N. asteroides
extended into pulmonary airspaces in anti-CXCR2 or
anti-Ly-6G-treated mice. In comparison, airspace invasion was only
rarely seen in control infected mice.
|
The effect of anti-CXCR2 or anti-Ly-6G treatment on
bacterial clearance was determined 24 h after inoculation.
Treatment of mice with anti-CXCR2 or anti-Ly-6G before
bacterial inoculation resulted in a >100 fold increase in total lung
bacterial burdens when compared with control Ab-treated mice (Fig. 8).
|
MIP-2 and KC are both rapidly produced at high levels during the
normal course of nocardial infection. Because anti-CXCR2- or
anti-Ly-6G-treated mice developed invasive disease in response to
N. asteroides challenge, we reasoned that both MIP-2 and KC
would be strongly up-regulated in these mice. MIP-2 (2.7-fold) and KC
(3.6-fold) were induced in control mice infected with a sublethal dose
(1–2 x 105 CFU) of GUH-2, albeit at lower
levels than seen with higher inoculum doses (see Table I
). Both
anti-CXCR2- and anti-Ly-6G-treated mice had greatly enhanced
production of MIP-2 (anti-CXCR2, 63 fold; anti-Ly-6G, 59 fold)
and KC (anti-CXCR2, 347-fold; anti-Ly-6G, 205-fold) compared
with saline-treated mice. These elevated levels are in part likely due
to the increased pulmonary bacterial burden seen in these mice
(Fig. 8).
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The rapid up-regulation of the ELR+ CXC chemokines MIP-2 and KC suggests an important role for this family of chemokines in neutrophil recruitment during pulmonary nocardiosis. When MIP-2 bioactivity was neutralized in vivo before infection, no detrimental effects on survival, neutrophil recruitment, or bacterial clearance were seen. CXC chemokines display functional redundancy and overlapping neutrophil chemotactic activity between numerous members of this chemokine family. Our data using a ligand blocking anti-CXCR2 Ab clearly indicates a critical role for CXCR2 ligands as a family in the recruitment of neutrophils to sites of nocardial infection. Of the murine CXCR2 ligands, MIP-2 and KC are the best studied. MIP-2 and KC have been shown to play important roles in neutrophil dependent pulmonary host defenses in response to other bacterial pathogens (17, 36). The inability of neutralizing anti-MIP-2 Ab to alter neutrophil recruitment during N. asteroides infection suggests additional or alternative CXCR2 ligand usage. The rapid and sustained production of KC during the first 3 days post inoculation would suggest an important role for this chemokine during nocardiosis. We are currently attempting to generate in vivo neutralizing anti-KC Abs which will allow us to systematically determine the effects of anti-KC alone or in combination with anti-MIP-2. Other intriguing ELR+ CXC chemokine candidates include LPS-induced CXC chemokine (LIX) and the recently described lungkine. LIX has significant structural homology with human epithelial neutrophil-activating protein-78 and granulocyte chemotactic protein-2 (37, 38). During murine endotoxemia, prominent LIX expression was observed in heart tissue with lesser amounts seen in lung (39). Lungkine is of particular interest in that it is selectively produced by bronchoepithelial cells and induces neutrophil migration in vivo and in vitro (40). Although not formally shown to utilize the CXCR2 receptor, similarities in biological activity of lungkine with known CXCR2 ligands suggest usage of this receptor. Current studies are ongoing examining the role of lungkine and LIX in the host response to N. asteroides pulmonary infection.
Our observations point to a critical role for neutrophils in host
survival and eventual resolution of pulmonary nocardiosis. Mice treated
with anti-CXCR2 or anti-Ly-6G are exquisitely sensitive to
nocardial infection, requiring 100 fold fewer inoculated bacteria to
achieve an equivalent lethal dose seen in control mice. These mice are
also severely impaired in their ability to clear the pulmonary
infection, displaying a 100 fold increase in bacterial burden 24 h
after inoculation. These data extend a previous report indicating
increased pulmonary nocardial burden in neutrophil depleted mice
(12). Histological sections confirm the extensive growth
of branching chains of N. asteroides in the absence of
neutrophils (Fig. 7). Nocardial filaments were also seen extending from
masses of Nocardia into pulmonary airspaces. This type of
airspace invasion was rarely observed in nondepleted animals.
Additionally, epithelial cells lining the airspaces of nocardial
infected, neutrophil depleted mice appear enlarged and possibly
disrupted. The strain of N. asteroides used in these studies
(GUH-2) has been shown to specifically bind to and penetrate pulmonary
epithelial cells in vivo and in vitro (27, 41). It is
possible that in the absence of neutrophils, enhanced pulmonary
epithelial cell invasion occurs, resulting in cellular injury and a
likely worsening pathology.
In addition to inducing neutrophil migration,
ELR+ CXC chemokines have been shown to activate
neutrophils. Mice receiving anti-CXCR2 treatment before infection
still contained significantly more neutrophils than did anti-Ly-6G
treated mice (Fig. 6). It is likely that anti-CXCR2 treatment, in
addition to blocking neutrophil recruitment, also prevented these
resident cells from becoming activated by the high levels of CXC
chemokines produced locally in the lung. This may in part explain why
anti-CXCR2 treated mice displayed identical mortality rates
and pulmonary bacterial burden as anti-Ly-6G mice while containing
significantly more neutrophils.
The CXCR2 blockade studies clearly indicate the necessity of CXC chemokines for neutrophil recruitment in response to N. asteroides pulmonary challenge and that in their absence mortality rates are greatly elevated. Receptor blockage or ligand neutralization studies are useful for determining which cytokines are required for the clearance of an infectious agent. A logical extension of these studies would be to determine the therapeutic benefits of specific cytokine overexpression during infection. We have recently shown that transgenic mice expressing the chemokine KC driven by a lung specific promoter have increased resistance to Klebsiella pneumoniae infection (36). Preliminary studies using these mice indicate that lung specific overexpression of KC confers enhanced resistance to N. asteroides infection. Further studies are ongoing examining the role of KC in pulmonary nocardiosis.
We observed enhanced production of MIP-2 and KC in anti-CXCR2 or
anti-Ly-6G treated mice suggesting that CXC chemokine production is
independent of total lung neutrophil numbers. Elevated levels of MIP-2
and KC in these treated mice is in part likely due to the increased
pulmonary bacterial burden in these mice (Fig. 8). Alternatively, the
absence of recruited neutrophils into the lung may result in impaired
binding and uptake of CXCR2 ligands via receptor internalization.
Our data provide direct evidence linking CXCR2 ligands and neutrophil recruitment during nocardial pneumonia. Furthermore, the inability of anti-MIP-2 treatment to negatively alter the outcome of infection lends further support to the concept of CXC chemokine redundancy, resulting in the increased potential for neutrophil recruitment in the absence of any single CXC chemokine. For infections highly dependent on neutrophils, such as pulmonary nocardiosis, this is of critical importance.
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Thomas A. Moore, University of Michigan Medical Center, Division of Pulmonary and Critical Care Medicine, 6301 MSRB III, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0642. E-mail address:
3 Abbreviations used in this paper: MIP-2, macrophage inflammatory protein-2; CXCR1 and 2, CXC chemokine receptor-1 and -2; LIX, LPS-induced CXC chemokine; BHI, brain-heart infusion; MPO, myeloperoxidase; H&E, hematoxylin and eosin; GMS, Gomori methenamine-silver.
Received for publication August 23, 1999. Accepted for publication October 29, 1999.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
, GRO
, GRO
, neutrophil-activating peptide-2, and epithelial cell-derived neutrophil-activating peptide-78 are potent agonists for the type B, but not the type A, human interleukin-8 receptor. J. Biol. Chem. 271:20545.This article has been cited by other articles:
|
|
 |
|
  D. D. Kish, X. Li, and R. L. Fairchild CD8 T Cells Producing IL-17 and IFN-{gamma} Initiate the Innate Immune Response Required for Responses to Antigen Skin Challenge J. Immunol., May 15, 2009; 182(10): 5949 - 5959. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. M. Farooq, R. Stillie, M. Svensson, C. Svanborg, R. M. Strieter, and A. W. Stadnyk Therapeutic Effect of Blocking CXCR2 on Neutrophil Recruitment and Dextran Sodium Sulfate-Induced Colitis J. Pharmacol. Exp. Ther., April 1, 2009; 329(1): 123 - 129. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Andreasen and N. H. Carbonetti Role of Neutrophils in Response to Bordetella pertussis Infection in Mice Infect. Immun., March 1, 2009; 77(3): 1182 - 1188. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Craig, J. Mai, S. Cai, and S. Jeyaseelan Neutrophil Recruitment to the Lungs during Bacterial Pneumonia Infect. Immun., February 1, 2009; 77(2): 568 - 575. [Full Text] [PDF]
|
|
|
|
 |
|
 R. Yanagisawa, H. Takano, T. Ichinose, K. Mizushima, M. Nishikawa, I. Mori, K.-i. Inoue, K. Sadakane, and T. Yoshikawa Gene Expression Analysis of Murine Lungs Following Pulmonary Exposure to Asian Sand Dust Particles Experimental Biology and Medicine, September 1, 2007; 232(8): 1109 - 1118. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Rios-Santos, J. C. Alves-Filho, F. O. Souto, F. Spiller, A. Freitas, C. M. C. Lotufo, M. B. P. Soares, R. R. dos Santos, M. M. Teixeira, and F. de Queiroz Cunha Down-regulation of CXCR2 on Neutrophils in Severe Sepsis Is Mediated by Inducible Nitric Oxide Synthase-derived Nitric Oxide Am. J. Respir. Crit. Care Med., March 1, 2007; 175(5): 490 - 497. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Okutani, M. Lodyga, B. Han, and M. Liu Src protein tyrosine kinase family and acute inflammatory responses Am J Physiol Lung Cell Mol Physiol, August 1, 2006; 291(2): L129 - L141. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. L. Rittner, S. A. Mousa, D. Labuz, K. Beschmann, M. Schafer, C. Stein, and A. Brack Selective local PMN recruitment by CXCL1 or CXCL2/3 injection does not cause inflammatory pain J. Leukoc. Biol., May 1, 2006; 79(5): 1022 - 1032. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Martens, N. D. Cohen, S. L. Jones, T. A. Moore, and J. F. Edwards Protective Role of Neutrophils in Mice Experimentally Infected with Rhodococcus equi Infect. Immun., October 1, 2005; 73(10): 7040 - 7042. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Iyoda, K. Nagata, M. Akashi, and Y. Kobayashi Neutrophils Accelerate Macrophage-Mediated Digestion of Apoptotic Cells In Vivo as Well as In Vitro J. Immunol., September 15, 2005; 175(6): 3475 - 3483. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Johnston, J. P. Mizgerd, and S. A. Shore CXCR2 is essential for maximal neutrophil recruitment and methacholine responsiveness after ozone exposure Am J Physiol Lung Cell Mol Physiol, January 1, 2005; 288(1): L61 - L67. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Hess, T. K. Means, P. Autissier, T. Woodberry, M. Altfeld, M. M. Addo, N. Frahm, C. Brander, B. D. Walker, and A. D. Luster IL-8 responsiveness defines a subset of CD8 T cells poised to kill Blood, December 1, 2004; 104(12): 3463 - 3471. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. G. Scorpio, M. Akkoyunlu, E. Fikrig, and J. S. Dumler CXCR2 Blockade Influences Anaplasma phagocytophilum Propagation but Not Histopathology in the Mouse Model of Human Granulocytic Anaplasmosis Clin. Vaccine Immunol., September 1, 2004; 11(5): 963 - 968. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Lomas-Neira, C.-S. Chung, P. S. Grutkoski, E. J. Miller, and A. Ayala CXCR2 inhibition suppresses hemorrhage-induced priming for acute lung injury in mice J. Leukoc. Biol., July 1, 2004; 76(1): 58 - 64. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. D. Sue, J. A. Belperio, M. D. Burdick, L. A. Murray, Y. Y. Xue, M. C. Dy, J. J. Kwon, M. P. Keane, and R. M. Strieter CXCR2 Is Critical to Hyperoxia-Induced Lung Injury J. Immunol., March 15, 2004; 172(6): 3860 - 3868. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. P. Keane, J. A. Belperio, Y. Y. Xue, M. D. Burdick, and R. M. Strieter Depletion of CXCR2 Inhibits Tumor Growth and Angiogenesis in a Murine Model of Lung Cancer J. Immunol., March 1, 2004; 172(5): 2853 - 2860. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. L. Ness, C. M. Hogaboam, R. M. Strieter, and S. L. Kunkel Immunomodulatory Role of CXCR2 During Experimental Septic Peritonitis J. Immunol., October 1, 2003; 171(7): 3775 - 3784. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. L. Miller, R. M. Strieter, A. D. Gruber, S. B. Ho, and N. W. Lukacs CXCR2 Regulates Respiratory Syncytial Virus-Induced Airway Hyperreactivity and Mucus Overproduction J. Immunol., March 15, 2003; 170(6): 3348 - 3356. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Inoue, H. Nakamura, K. Otake, H. Saito, K. Terashita, J. Sato, H. Takeda, and H. Tomoike Impaired Pulmonary Inflammatory Responses Are a Prominent Feature of Streptococcal Pneumonia in Mice with Experimental Emphysema Am. J. Respir. Crit. Care Med., March 1, 2003; 167(5): 764 - 770. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Garcia-Ramallo, T. Marques, N. Prats, J. Beleta, S. L. Kunkel, and N. Godessart Resident Cell Chemokine Expression Serves as the Major Mechanism for Leukocyte Recruitment During Local Inflammation J. Immunol., December 1, 2002; 169(11): 6467 - 6473. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Mehrad, M. Wiekowski, B. E. Morrison, S.-C. Chen, E. C. Coronel, D. J. Manfra, and S. A. Lira Transient Lung-Specific Expression of the Chemokine KC Improves Outcome in Invasive Aspergillosis Am. J. Respir. Crit. Care Med., November 1, 2002; 166(9): 1263 - 1268. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A. Skidgel, X.-p. Gao, V. Brovkovych, A. Rahman, D. Jho, S. Predescu, T. J. Standiford, and A. B. Malik Nitric Oxide Stimulates Macrophage Inflammatory Protein-2 Expression in Sepsis J. Immunol., August 15, 2002; 169(4): 2093 - 2101. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. R. Chung, T. Chitnis, R. J. Panzo, D. L. Kasper, M. H. Sayegh, and A. O. Tzianabos CD4+ T Cells Regulate Surgical and Postinfectious Adhesion Formation J. Exp. Med., June 3, 2002; 195(11): 1471 - 1478. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X.-p. Gao, T. J. Standiford, A. Rahman, M. Newstead, S. M. Holland, M. C. Dinauer, Q.-h. Liu, and A. B. Malik Role of NADPH Oxidase in the Mechanism of Lung Neutrophil Sequestration and Microvessel Injury Induced by Gram-Negative Sepsis: Studies in p47phox-/- and gp91phox-/- Mice J. Immunol., April 15, 2002; 168(8): 3974 - 3982. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Tam, D. P. King, and B. L. Beaman Increase of {gamma}{delta} T Lymphocytes in Murine Lungs Occurs during Recovery from Pulmonary Infection by Nocardia asteroides Infect. Immun., October 1, 2001; 69(10): 6165 - 6171. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. M. Lindell, T. J. Standiford, P. Mancuso, Z. J. Leshen, and G. B. Huffnagle Macrophage Inflammatory Protein 1{alpha}/CCL3 Is Required for Clearance of an Acute Klebsiella pneumoniae Pulmonary Infection Infect. Immun., October 1, 2001; 69(10): 6364 - 6369. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Akkoyunlu, S. E. Malawista, J. Anguita, and E. Fikrig Exploitation of Interleukin-8-Induced Neutrophil Chemotaxis by the Agent of Human Granulocytic Ehrlichiosis Infect. Immun., September 1, 2001; 69(9): 5577 - 5588. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. J. Simpson, W. A. H. Wallace, M. E. Marsden, J. R. W. Govan, D. J. Porteous, C. Haslett, and J.-M. Sallenave Adenoviral Augmentation of Elafin Protects the Lung Against Acute Injury Mediated by Activated Neutrophils and Bacterial Infection J. Immunol., August 1, 2001; 167(3): 1778 - 1786. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Kielian, B. Barry, and W. F. Hickey CXC Chemokine Receptor-2 Ligands Are Required for Neutrophil-Mediated Host Defense in Experimental Brain Abscesses1 J. Immunol., April 1, 2001; 166(7): 4634 - 4643. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. R. Hall, E. Diaconu, R. Patel, and E. Pearlman CXC Chemokine Receptor 2 But Not C-C Chemokine Receptor 1 Expression Is Essential for Neutrophil Recruitment to the Cornea in Helminth-Mediated Keratitis (River Blindness) J. Immunol., March 15, 2001; 166(6): 4035 - 4041. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Faouzi, B. E. Burckhardt, J. C. Hanson, C. B. Campe, L. W. Schrum, R. A. Rippe, and J. J. Maher Anti-Fas Induces Hepatic Chemokines and Promotes Inflammation by an NF-kappa B-independent, Caspase-3-dependent Pathway J. Biol. Chem., December 21, 2001; 276(52): 49077 - 49082. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
