The JI
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     
 

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Befus, A. D.
Right arrow Articles by Bateman, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Befus, A. D.
Right arrow Articles by Bateman, A.
The Journal of Immunology, 1999, 163: 947-953.
Copyright © 1999 by The American Association of Immunologists

Neutrophil Defensins Induce Histamine Secretion from Mast Cells: Mechanisms of Action1

A. Dean Befus2,*, Connie Mowat{dagger}, Mark Gilchrist*, Jing Hu{ddagger}, Samuel Solomon{ddagger} and Andrew Bateman{ddagger}

* Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada; {dagger} Immunology Research Group, University of Calgary, Calgary, Alberta, Canada; and {ddagger} Department of Medicine, Obstetrics and Gynecology, Endocrine Laboratory, Royal Victoria Hospital/McGill University, Montreal, Quebec, Canada


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Defensins are endogenous antimicrobial peptides stored in neutrophil granules. Here we report that a panel of defensins from human, rat, guinea pig, and rabbit neutrophils all have histamine-releasing activity, degranulating rat peritoneal mast cells with EC50 ranging from 70 to 2500 nM, and between 45 and 60% of the total histamine released. The EC50 for defensin-induced histamine secretion correlates with their net basic charge at neutral pH. There is no correlation between histamine release and antimicrobial potency. Degranulation induced by defensins has characteristics similar to those of activation by substance P. The maximum percent histamine release is achieved in <10 s, and it can be markedly inhibited by pertussis toxin (100 ng/ml) and by pretreatment of mast cells with neuraminidase. These properties differ from those for degranulation induced by IgE-dependent Ag stimulation and by the calcium ionophore A23187. GTPase activity, a measure of G protein activation, was induced in a membrane fraction from mast cells following treatment with defensin. Thus, neutrophil defensins are potent mast cell secretagogues that act in a manner similar to substance P and 48/80, through a rapid G protein-dependent response that is mechanistically distinct from Ag/IgE-dependent mast cell activation. Defensins may provide important pathways for communication between neutrophils and mast cells in defenses against microbial agents and in acute inflammatory responses.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
Activation of mast cells by cross-linkage of surface IgE with specific Ag is widely recognized as a major pathway for the induction of inflammatory responses, particularly immediate hypersensitivity reactions (1, 2). There are other pathways of mast cell activation, (2, 3, 4) but, unfortunately, little is known about the significance of these in host defenses or in the pathogenesis of inflammatory diseases. For example, Askenase and co-workers (5) have identified an Ag-specific, T cell-derived factor that can sensitize mouse mast cells and together with Ag selectively induce serotonin release as opposed to histamine secretion. Several other secretagogues can activate selected mast cell populations, including anaphylatoxins (C3a and C5a), neuropeptides (substance P, neurotensin, vasoactive intestinal peptide, somatostatin, etc.), bee venom peptides, 48/80, polylysine, and polymyxin (2, 3, 4, 6, 7, 8, 9, 10). Many of these secretagogues share the characteristic of being polycations. Recent evidence suggests that they act by direct stimulation of G proteins of the Gi subtype following their binding to complementary cell surface sites, not to classical receptors (7, 10, 11, 12, 13). The pathway of activation involved is distinct from that of IgE-dependent mast cell activation.

In studies largely with human basophils, a diverse group of substances that induce histamine secretion has been identified. These are collectively referred to as histamine-releasing factors (HRF)3 (3) and can be derived from T and B lymphocytes, alveolar macrophages, platelets, mononuclear cells, fibroblasts, and neutrophils (14). HRF have been found in nasal washings from atopic individuals (15), bronchoalveolar lavage fluids from individuals with pulmonary fibrosis (16), tissue fluids from Ag-stimulated late phase skin reactions (17), and PBMC of individuals with occupational asthma (18). Several forms of HRF can be derived from mononuclear cells that have been activated (14). An 8- to 10-kDa form appears to be connective tissue-activating peptide, and its closely related cleavage product is neutrophil-activating peptide (19). Monocyte chemotactic and activating factor (20), monocyte chemotactic protein 1 (21), macrophage inflammatory protein-1{alpha} (22), RANTES (23), macrophage chemotactic protein-2 and –3 and fibroblast-induced cytokine (24), and IL-3 (25) also induce histamine secretion from human basophils. In addition, a novel IgE-dependent HRF has been recently defined by MacDonald and colleagues as highly homologous with mouse p21 and human p23 (26). Neutrophil-derived HRF appears to be different from these, because it is constitutively produced, heat stable, and has an estimated molecular mass of 1400–2300 Da (27). Others have identified that HRF activity from neutrophils lies within cationic lysosomal proteins of about 5 kDa (28).

Recently, there has been an explosion of interest in defensins, a family of highly cationic proteins of about 3500 Da derived from neutrophils and other cells (29, 30, 31). Defensins are variably cationic, arginine-rich, nonglycosylated peptides that contain a characteristic cysteine motif. They are best known for their antimicrobial activity. Defensins have also been identified as corticostatins because they bind specifically to the ACTH receptor and inhibit the actions of ACTH on the adrenal glands (32, 33). They are also chemotactic for human monocytes (34), and at least two guinea pig defensins can induce histamine release from rat peritoneal mast cells (PMC) (35). Given this single report about the ability of defensins to induce histamine secretion and the possibility that neutrophil-derived HRF activity involves defensins (27, 28), we characterized the ability of several defensins to induce histamine secretion and studied their mode of action.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Animals

Outbred male Sprague Dawley rats (375–450 g) purchased from Charles River Canada (St. Constant, Canada) were used. They were maintained in an isolated room in filter-top cages to minimize unwanted infections. The animals were given food and water ad libitum and were maintained on a 12-h light (0700 h), 12-h dark (1900 h) cycle. No rats were used for experimentation until a minimum of 1 wk following arrival in our facilities, so as to reduce the effects of stress associated with transport, handling, and new environmental conditions. All experimental procedures were approved by the University animal care committee and were performed in accordance with the guidelines of the Canadian Council on Animal Care.

Either normal rats or rats infected 35–100 days previously with 3000 third stage larvae of the nematode, Nippostrongylus brasiliensis (to induce mast cell hyperplasia and IgE-dependent sensitization) were used to isolate PMC for study (8).

Mast cell isolation and enrichment

Normal rats or rats previously infected with N. brasiliensis were anesthetized, and 15 ml of cold Tyrode’s solution containing 12 mM HEPES and 1% BSA, pH 7.3 (HTB), were injected into the peritoneal cavity. The abdomen was massaged, and the fluid was collected and centrifuged for 4 min at 180 x g at 4°C. Peritoneal exudate cells were layered on a 30%/80% discontinuous gradient of Percoll (Pharmacia, Dorval, Canada) for 20 min at 220 x g at 4°C. The cell pellet was washed twice and examined for mast cell purity (>=98%) and viability (>=97%) by trypan blue exclusion (8). Mast cell viability was also assessed using trypan blue exclusion following treatment with each of the peptides tested as well as with pertussis toxin and neuraminidase treatments. None of the treatments significantly altered viability.

Histamine secretion and its modulation by pertussis toxin and neuraminidase

For studies of histamine secretion, 50,000 highly enriched PMC (>=98%) and the secretagogues to be used were preincubated separately at 37°C for 5 min, and then the secretagogues were added to the cells and incubated at 37°C for 10 min. The reaction was terminated by the addition of 1 ml of cold HTB and was centrifuged at 4°C to separate the supernatant and cell pellet. After the pellets were brought to 1.5 ml using HTB, the samples were boiled for 10 min to release cell-associated histamine and destroy histaminase activity. After TCA precipitation of proteins, histamine levels were measured in both supernatant and pellet fractions by fluorometric assay (36) using a model LS-3B Perkin-Elmer fluorescence spectrometer (Norwalk, CT). Histamine release was expressed as a percentage of the total cellular histamine content as calculated by the formula: (histamine in supernatant/histamine in supernatant and pellet) x 100. Spontaneous release of histamine was normally <2% of the total and was subtracted from the percent release to give the specific secretion shown in the text, tables, and figures. From dose-response curves of various secretagogues, the concentrations that specifically release 50% of the cellular histamine were calculated (EC50).

The secretagogues used in the studies included an extract of N. brasiliensis Ags (8), the neuropeptide substance P (10-5 M), the ionophore A23187 (5 x 10-6 M), and a panel of defensins from humans, rabbits, and guinea pigs. Defensins were isolated from bone marrow for the rabbit (37) and guinea pig (38) peptides and from leukocytes obtained from the peritoneal exudate of patients with peritonitis for the human peptides (39, 40). The peptides were purified by reverse phase and size exclusion chromatography as previously described (37, 38, 39, 40). The identity, purity, and quantity of each peptide were determined by amino acid analysis. Purified peptides were stored lyophilized at -20°C until use. The nomenclature and structure of the defensins used in this manuscript are summarized in Table IGo. The guinea pig peptide GPCSIII is more closely related to the protegrin family (41) of cysteine-rich cationic neutrophil peptides than to the classic defensins and exists as an antiparallel homodimer (38).


View this table:
[in this window]
[in a new window]
  		Table I. The nomenclature and primary structures of defensins tested for mast cell degranulating activity

 
To compare the time course of histamine secretion induced by various secretagogues, the secretory reaction was abruptly terminated at various times following mixing the secretagogue and cells by adding 1 ml of ice-cold HTB, placing the tubes immediately on ice, and then separating into supernatant and pellet fractions by centrifugation at 180 x g for 5 min at 4°C. In several experiments, highly enriched mast cells were pretreated with pertussis toxin (List Biochemical Laboratory, Campbell, CA) for 2 h at 37°C (42) or with type V neuraminidase from Clostridium perfringens (Sigma, St. Louis, MO) for 1 h at 37°C (43). Cells were washed twice with 1 ml of HTB and were resuspended in HTB for subsequent studies of their responses to secretagogues.

Isolation of mast cell membrane fraction

A mast cell membrane fraction was isolated as described previously (44). Briefly, purified PMC (30 x 106) were resuspended in homogenization buffer (HEPES buffer with 2 mM MgCl2, 1 mM ATP, 100 µg/ml PMSF, and a protease inhibitor mixture consisting of 5 µg/ml each of leupeptin, aprotinin, and tosyl-arginine methyl ester (TAME)). Cells were ruptured by repeated passage (5–10 times) through a 12-µm clearance in a ball-bearing homogenizer (EMBL, Heidelberg, Germany), with resulting organelles removed by centrifugation at 400 x g for 10 min. The clear supernatant was then centrifuged at 100,000 x g for 1 h at 4°C. The membrane pellet was resuspended in a small volume of 10 mM triethanolamine/HCl buffer and was stored at -70°C until use.

GTPase assay

GTPase activity was assayed by the hydrolysis of phosphatei from [{gamma}-32P]GTP as previously described (45). Briefly, a reaction mixture (100 µL) containing 50 mM triethanolamine/HCl (pH 7.5), 2 mM MgCl2, 1 mM DTT, 0.1 mM EGTA, 2 mg/ml BSA, 0.8 mM adenosine 5'-(ß,{gamma}-imino)-triphosphate, 0.1 mM ATP, 0.4 mg/ml creatine kinase, 5 mM creatine phosphate, and 5 nM [{gamma}-32P]GTP was prewarmed (5 min, 30°C). Reactions were started by addition of membrane fraction (1.0–2.0 µg of protein) to the prewarmed incubation mixture containing substance P or NP3a and allowed to proceed for 25 min at 30°C. The reaction was stopped by addition of 700 µL of 10 mM sodium phosphate (pH 2.0) containing 5% (w/v) activated charcoal. The tubes were chilled for 30 min on ice, then centrifuged at 13,000 x g for 10 min. A 500-µL aliquot was removed, and GTPase activity was evaluated by determination of Cherenkov radiation.

Statistical analyses

Data are given as the mean ± SEM. Differences among treatment groups were examined for significance by two-way ANOVA. Individual differences were assessed for statistical significance (p < 0.05) by paired or unpaired Student’s t test.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
Dose response and EC50 for defensins

The abilities of various concentrations of rabbit, guinea pig, and human defensins to induce histamine secretion from purified rat PMC were studied (Fig. 1Go). The rabbit defensins NP1, NP3a, and NP3b induced histamine secretion at low nanomolar concentrations and induced a maximum of 50–60% specific histamine release. The EC50 for these rabbit peptides varied from 70–620 nM (Table IIGo). A similar pattern of histamine secretion occurred with guinea pig defensins, GPNP1 and GPCSIII (Fig. 1GoB and Table IIGo). The human defensins HNP1 and HNP4, were less potent in inducing histamine secretion from rat mast cells. At 2.5 µM the maximum histamine secretion was 40–55% with EC50 for HNP1 and for HNP4 of 2.9 and 2.2 µM, respectively (Fig. 1GoC and Table IIGo). Although the amounts of rat defensins available for study were limited, in a single experiment R2 (5 nM), R4 (0.5 nM), and R5 (0.5 nM) induced histamine secretion (15.2, 51.7, and 45.8%, respectively); R3 induced no histamine secretion.



View larger version (13K):
[in this window]
[in a new window]
  		FIGURE 1. Specific histamine secretion induced by 10-min exposure of purified rat peritoneal mast cells to defensins from: A, rabbit (NP1, NP3a, and NP3b); B, guinea pig (GPCSI, GPCSIII); and human (HNP1 and HNP4). Values are the mean ± SE (n = 4 separate experiments for each defensin). The percent histamine secretion for each of the rabbit peptides (A) is significantly different from the others at 50, 140, and 420 nM; for the guinea pig peptides (B) at 30, 90, and 280 nM; and for the human peptides (C) at 280, 830, and 2500 nM (p <= 0.05).

 

View this table:
[in this window]
[in a new window]
  		Table II. Maximum histamine secretion, EC50, and nominal net charge at pH 7.4 of defensins tested for mast cell degranulating activity

 
The EC50 of the defensins studied generally correlated with the nominal net charge of the peptides at pH 7.4 as calculated from their known sequences (Table IIGo). These values correlate with their relative charge as determined by acid-urea gel electrophoresis. Rabbit NP3a was the most potent inducer of specific histamine release (EC50, 70 nM; Table IIGo). Thus, for further studies of the mechanisms involved in histamine secretion with defensins we used NP3a as a representative peptide. For comparisons, the characteristics of histamine secretion induced by NP3a under different experimental conditions (time-course analysis and effects of pertussis toxin and neuraminidase) were compared with those of substance P, Ag, and the calcium ionophore A23187. Interestingly, NP3a did not induce histamine secretion from mucosal mast cells isolated (8) from rat small intestinal mucosa (results not shown).

Time course analysis of histamine secretion

Given that differences in the time course of histamine secretion occur with various secretagogues (polycations have a rapid time course, <=10 s) and relate to the activation pathways involved, we studied the time course of histamine secretion induced by NP3a and other secretagogues. NP3a and the polycation substance P exhibited a rapid time course (<10 s required for maximum percent histamine release), whereas the time courses of Ag- and ionophore (A23187)-induced histamine secretion were delayed and reached a maximum after 20 or at least 60 s, respectively (Fig. 2Go).



View larger version (19K):
[in this window]
[in a new window]
  		FIGURE 2. Time-course analysis of specific histamine secretion induced by substance P (10-5 M), NP3a (140 nM), A23187 (5 x 10-6 M), or N. brasiliensis (five worm equivalents) Ag (mean ± SE; n = 3–6 experiments for each secretagogue). NP3a and substance P are significantly different from Ag and A23187 at 5 and 10 s (*, p <= 0.05).

 
Effects of pretreatment with pertussis toxin on histamine secretion

Histamine secretion induced by polycations such as 48/80 and substance P is highly sensitive to pertussis toxin, whereas Ag- and ionophore-induced histamine release is not (10, 13, 46, 47, 48). Therefore, we investigated the effects of pertussis toxin on NP3a-induced histamine secretion (Fig. 3Go). Purified PMC were preincubated for 2 h with various concentrations (1–100 ng/ml) of pertussis toxin, washed, and then stimulated with various secretagogues for 10 min. Pertussis toxin (100 ng/ml) almost completely inhibited histamine secretion induced by substance P (94.5 ± 3.8% inhibition) and NP3a (96.3 ± 2.3% inhibition), whereas it was without effect on A23187-induced histamine secretion (data not shown) and only partially inhibited (48 ± 5.5%) Ag-induced histamine secretion. Inhibition was evident with as little as 10 ng/ml pertussis toxin during a 2-h pretreatment.



View larger version (16K):
[in this window]
[in a new window]
  		FIGURE 3. Effects of pretreatment with pertussis toxin (2 h, 37°C) on the inhibition of specific histamine secretion stimulated by substance P (10-5 M), NP3a (140 nM), A23187 (5 x 10-6 M), or N. brasiliensis (five worm equivalents) Ag (mean ± SE; n = 3–6). NP3a and substance P are significantly different from Ag and A23187 at all doses of pertussis toxin (*, p <=0.05).

 
Effects of pretreatment with neuraminidase on histamine secretion

Histamine secretion induced by polycations, but not by A23187, is also highly sensitive to inhibition by the removal of sialic acid residues from the cell surface using neuraminidase (10). Thus, to characterize the sensitivity of NP3a-induced histamine secretion to neuraminidase, we pretreated purified PMC with various concentrations (0.01–0.1 U/ml) of neuraminidase for 1 h, washed them, and then challenged them with various secretagogues (Fig. 4Go). NP3a- and substance P-induced histamine secretion was highly sensitive to the removal of sialic acid residues (80.0 ± 2.4% and 72.7 ± 8.0% inhibition, respectively). By contrast, histamine secretion induced by Ag stimulation was partially (33.8 ± 5.2%) inhibited by neuraminidase treatment, and there was no effect of neuraminidase on histamine secretion induced by A23187 (data not shown).



View larger version (17K):
[in this window]
[in a new window]
  		FIGURE 4. Effects of pretreatment with neuraminidase (1 h, 37°C) on the inhibition of specific histamine secretion stimulated by substance P (10-5 M), NP3a (140 nM), A23187 (5 x 10-6 M), or N. brasiliensis (five worm equivalents) Ag (mean ± SE inhibition, n = 4–5; n = 2 for A23187). NP3a and substance P are significantly different from Ag and A23187 at neuraminidase concentrations of 0.025, 0.05, 0.075, and 0.1 U/ml (*, p <= 0.05).

 
Enhancement of GTPase activity by NP3a

Because the activation of histamine secretion from mast cells by NP3a appeared to be similar to that of substance P and presumably other polycationic peptides, we studied whether NP3a could induce GTPase activity, a measure of activation of G proteins, in a membrane fraction of PMC. An isolated membrane fraction from purified PMC induced a significant (p < 0.05) GTPase response in the presence of 140 nM NP3a (7.7 ± 1.6 pmol/min/µg), consistent with or greater than the positive response to 10-5 M substance P (7.3 ± 1.7 pmol/min/mg; Fig. 5Go). This was reproducible in multiple studies with a single membrane preparation as well as with independent membrane preparations.



View larger version (12K):
[in this window]
[in a new window]
  		FIGURE 5. Increase in hydrolysis of phosphate from [{gamma}-32P]GTP (GTPase activity) following treatment of membrane fraction isolated from mast cells with substance P (10-5 M) or rabbit defensin, NP3a (140 nM), at 30°C (results of three experiments from two independent membrane preparations: *, p < 0.05).

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
Several cationic peptides, including venom peptides such as mast cell-degranulating peptide (MCDP), and neuroendocrine peptides such as substance P, vasoactive intestinal polypeptide, and somatostatin promote IgE-independent histamine release from mast cells. Rat intestinal mucosal mast cells often contact subepithelial substance P neurons (49), suggesting a physiological role for substance P-induced mast cell degranulation. This observation received strong support when Janiszewski et al. (9), showed that concentrations as low as 5 pM substance P primed mast cells for subsequent activation by substance P and other secretagogues. However, peptide-induced histamine release also may be an unwanted side effect in the development of pharmacologically useful peptide agents; for example, many luteinizing hormone-releasing hormone antagonists degranulate mast cells (50). Neutrophils elaborate low molecular mass (<=5 kDa) HRF whose identity is not known but which appears by biological and chromatographic criteria to differ from other biochemically characterized histamine-releasing polypeptides. Neutrophil-derived guinea pig defensins activate histamine release from mast cells (35). We therefore examined the histamine-releasing properties and mechanisms of action of several defensins from different species as candidate neutrophil-derived HRF.

The ability to degranulate mast cells is common to all defensins tested, with EC50 ranging from 70 nM to 2.9 µM. Defensins resemble wasp MCDP in terms of their cysteine-rich character and their potencies on rat PMC: 20 nM for MCDP (51, 52) and 70 nM for NP3a. On a molar basis the EC50 for the highly cationic defensins (net positive charge at pH 7.4 above 6) are lower or in the same range as those for anaphylatoxins C5a and C3a (53) on dermal mast cells and are orders of magnitude lower than those of noncysteinyl neuroendocrine peptides (8) such as somatostatin (EC50, ~2.0 µM), vasoactive intestinal polypeptide (EC50, ~6.0 µM), and substance P (EC50, ~40.0 µM) on rat PMC. The range of defensin EC50 as mast cell secretagogues shows a strong correlation with the net charge of the peptide at pH 7.4; the more basic defensins are more potent mast cell-degranulating agents. The potency of mast cell degranulation also tends to follow the rank order of these peptides as inhibitors of the ACTH receptor (corticostatic activity), suggesting similarities in the underlying mechanisms of these two responses. HP-1 and HP-4, which have the weakest histamine-releasing activity are antimicrobial (54, 55), demonstrating that the structure-activity correlates that govern histamine secretion differ from those that determine microbicidal action.

In common with other cationic peptides, defensins degranulate mast cells through a pertussis toxin-inhibitable mechanism, implying an action on G proteins. The time course of histamine release by defensins is identical with that of substance P, and both peptides are inhibited by neuraminidase treatment of mast cells. Moreover, as with substance P, NP3a induces GTPase activity. Thus, the mechanism of defensin-induced mast cell degranulation is similar to that of other polycationic peptides. This is also consistent with the lack of effect of NP3a on histamine secretion from intestinal mucosal mast cells, as this mast cell subset is unresponsive to other polycations. This unresponsiveness may protect these mucosal mast cells from spurious activation by defensin-like cryptdins thought to be constitutively released from Paneth cells in the intestinal crypts (56). Alternately, cryptdins may activate mucosal mast cells, whereas neutrophil-derived defensins do not. Peptide-induced histamine release is thought to involve receptor-independent activation of G proteins (13). The details of how such peptides activate G proteins remain unclear, but involve direct interaction of the peptide with the G protein. Charge and membrane penetrance are important; however, HP-1, which is membrane penetrating (57), only weakly activates mast cell histamine secretion. In studies on synthetic magainin analogues (amphipathic helical antimicrobial peptides from frog skin) Cross et al. (58) were able to uncouple strong histamine-releasing activity from peptide-induced membrane perturbations. The amino acid configuration may exert an important influence on peptide-induced mast cell degranulation, since L- to D-arginine substitutions in substance P analogues, which conserved overall charge, showed reduced mast cell activation (58).

There is growing evidence of important communication between mast cells and neutrophils in inflammatory reactions. Neutrophil recruitment to inflammatory sites is mast cell dependent (59), involves their production of TNF-{alpha} (60), and has important antimicrobial activities (61, 62). In addition, mast cell-derived tryptase has a pronounced effect on neutrophil recruitment (63, 64). In turn, neutrophil-derived factors have long been implicated in histamine release at sites of inflammation, and defensin-induced histamine release may contribute to this process. During infection, plasma defensin concentrations may greatly exceed the levels that induce degranulation of mast cells in vitro. In sepsis, cumulative concentrations in plasma of the human defensins HNP1–3 rise from 40 ng/ml in healthy individuals to as high as 170 ng/ml (65, 66). Highly elevated levels of HNP1–3 occur in sputum from cystic fibrosis patients (67) and in pleural effusions from patients with empyema (68). Solid tissue infiltrated with neutrophils may have total HNP1–3 levels up to 25 nmol/g wet weight or roughly 90 µg (39). Defensins are prominent within the extracellular spaces of experimentally induced syphilitic lesions in rabbits (69). The plasma level of rabbit NP3a, the most active MCDP, increases from 8 ng/ml in uninfected animals to 234 ng/ml during experimental peritonitis (70). The release of defensins may arise both from the lysis of expended neutrophils and from cytokine-stimulated secretion. IL-8 (64, 68) or PMA (68) stimulates the release of HNP1–3 from human neutrophils, and at least in pleural effusions the local levels of IL-8 exceed the concentrations required to promote the secretion of neutrophil defensins.

Since defensins are released from neutrophils in response to IL-8 and can be proinflammatory (71), these peptides may also be released by mast cell-derived TNF-{alpha} and tryptase and accumulate at sites of inflammation. Thus, it appears that this bidirectional communication between mast cells and neutrophils is important in acute inflammatory responses. It may involve important innate responses that help direct the kinds of immune and inflammatory responses that evolve following injury and Ag exposure and clearly requires further study. Regardless of the physiological or pathological outcomes of defensin-induced histamine release and inflammatory cascades, the design of novel antibiotics based on defensin structures will have to take account of their propensity to degranulate mast cells.


   Acknowledgments
 
We thank Mrs. Fran Thompson for secretarial and editorial assistance. We also thank Drs. P. Lacy and F. L. Wills for their assistance with the GTPase assay.


   Footnotes
 
1 This work was supported by operating grants from the Medical Research Council of Canada (to A.D.B., A.B., and S.S.). Back

2 Address correspondence and reprint requests to Dr. Dean Befus, Glaxo-Heritage Asthma Research Laboratory, Pulmonary Research Group, Room 574, Heritage Medical Research Centre, University of Alberta, Edmonton, Alberta, T6G 2S2 Canada. E-mail address: Back

3 Abbreviations used in this paper: HRF, histamine-releasing factor; PMC, peritoneal mast cells; HTB, HEPES-Tyrode’s buffer; MCDP, mast cell-degranulating peptide. Back

Received for publication July 2, 1998. Accepted for publication April 30, 1999.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Galli, S. J.. 1993. New concepts about the mast cell. N. Engl. J. Med. 328:257.[Free Full Text]
  2. Befus, A. D., J. A. Denburg. 1999. Basophilic leucocytes: mast cells and basophils. R. Lee, and J. Foerster, and J. Lukens, and F. Paraskevas, and J. P. Greer, and G. M. Rodgers, eds. Wintrobe’s Clinical Hematology 10th Ed.362.-376. Williams & Wilkins, Baltimore.
  3. Foreman, J. C.. 1993. Non-immunological stimuli of mast cells and basophil leucocytes. J. C. Foreman, ed. Immunopharmacology of Mast Cells and Basophils 57.-70. Academic Press, London.
  4. Befus, A. D.. 1994. Inflammation: mast cells. P. L. Ogra, and J. Mestecky, and M. Lamm, and W. Strober, and J. McGhee, and J. Bienenstock, eds. Handbook of Mucosal Immunology 307.-314. Academic Press, San Diego.
  5. Askenase, P. W., R. W. Rosenstein, W. Ptak. 1983. T cells produce an antigen-binding factor with in vivo activity analogous to IgE antibody. J. Exp. Med. 157:862.[Abstract/Free Full Text]
  6. Fukuoka, Y., T. E. Hugli. 1990. Anaphylatoxin binding and degradation by rat peritoneal mast cells: mechanisms of degranulation and control. J. Immunol. 145:1851.[Abstract]
  7. Mousli, M., T. E. Hugli, Y. Landry, C. Bronner. 1992. A mechanism of action for anaphylatoxin C3a stimulation of mast cells. J. Immunol. 148:2456.[Abstract]
  8. Shanahan, F., J. A. Denburg, J. E. T. Fox, J. Bienenstock, D. Befus. 1985. Mast cell heterogeneity: effects of neuroenteric peptides on histamine release. J. Immunol. 135:1331.[Abstract]
  9. Janiszewski, J., J. Bienenstock, M. G. Blennerhassett. 1994. Picomolar doses of substance P trigger electrical responses in mast cells without degranulation. Am. J. Physiol. 267:C138.[Abstract/Free Full Text]
  10. Mousli, M., C. Bronner, J.-L. Bueb, E. Tschirhart, J.-P. Gies, Y. Landry. 1989. Activation of rat peritoneal mast cells by substance P and mastoparan. J. Pharmacol. Exp. Ther. 250:329.[Abstract/Free Full Text]
  11. Mousli, M., J.-L. Bueb, C. Bronner, B. Rouot, Y. Landry. 1990. G protein activation: a receptor-independent mode of action for amphiphilic neuropeptides and venom peptides. Trends Pharmacol. Sci. 11:358.[Medline]
  12. Aridor, M., L. M. Traub, R. Sagi-Eisenberg. 1990. Exocytosis in mast cells by basic secretagogues: evidence for direct activation of GTP-binding proteins. J. Cell Biol. 111:909.[Abstract/Free Full Text]
  13. Mousli, M., T. E. Hugli, Y. Landry, C. Bronner. 1994. Peptidergic pathway in human skin and rat peritoneal mast cell activation. Immunopharmacology 27:1.[Medline]
  14. Kaplan, A. P., S. Reddigari, M. Baeza, P. Kuna. 1991. Histamine releasing factors and cytokine-dependent activation of basophils and mast cells. Adv. Immunol. 50:237.[Medline]
  15. Sim, T. C., R. Alam, P. A. Forsythe, J. B. Welter, M. A. Lett-Brown, J. A. Grant. 1992. Measurement of histamine-releasing factor activity in individual nasal washings: relationship with atopy, basophil response, and membrane-bound IgE. J. Allergy Clin. Immunol. 89:1157.[Medline]
  16. Broide, D. H., C. A. Smith, S. I. Wasserman. 1990. Mast cells and pulmonary fibrosis: identification of a histamine releasing factor in bronchoalveolar lavage. J. Immunol. 145:1838.[Abstract]
  17. Warner, J. A., M. M. Pienkowski, M. Plaut, P. S. Norman, L. M. Lichtenstein. 1986. Identification of histamine releasing factor(s) in the late phase of cutaneous IgE-mediated reactions. J. Immunol. 136:2583.[Abstract]
  18. Herd, Z. L., D. I. Bernstein. 1994. Antigen-specific stimulation of histamine releasing factors in diisocyanate-induced occupational asthma. Am. J. Respir. Crit. Care Med. 150:988.[Abstract]
  19. Baeza, M. L., S. R. Reddigari, D. Kornfeld, N. Ramani, E. M. Smith, P. A. Hossler, T. Fischer, C. Castor, P. G. Gorevic, A. P. Kaplan. 1990. Relationship of one form of human histamine-releasing factor to connective tissue activating peptide-III. J. Clin. Invest. 85:1516.
  20. Kuna, P., S. R. Reddigari, D. Rucinski, J. J. Oppenheim, A. P. Kaplan. 1992. Monocyte chemotactic and activating factor is a potent histamine-releasing factor for human basophils. J. Exp. Med. 175:489.[Abstract/Free Full Text]
  21. Bischoff, S. C., M. Krieger, T. Brunner, C. A. Dahinden. 1992. Monocyte chemotactic protein 1 is a potent activator of human basophils. J. Exp. Med. 175:1271.[Abstract/Free Full Text]
  22. Alam, R., P. A. Forsythe, S. Stafford, M. A. Lett-Brown, J. A. Grant. 1992. Macrophage inflammatory protein-1{alpha} activates basophils and mast cells. J. Exp. Med. 176:781.[Abstract/Free Full Text]
  23. Bischoff, S. C., M. Krieger, T. Brunner, A. Rot, V. v. Tscharner, M. Baggiolini, C. A. Dahinden. 1993. RANTES and related chemokines activate human basophil granulocytes through different G protein-coupled receptors. Eur. J. Immunol. 23:761.[Medline]
  24. Alam, R., P. Forsythe, S. Stafford, J. Heinrich, R. Bravo, P. Proost, J. Van Damme. 1994. Monocyte chemotactic protein-2, monocyte chemotactic protein-3, and fibroblast-induced cytokine: three new chemokines induce chemotaxis and activation of basophils. J. Immunol. 153:3155.[Abstract]
  25. Tedeschi, A., M. Palella, N. Milazzo, M. Lorini, A. Miadonna. 1995. IL-3 induced histamine release from human basophils: dissociation from cationic dye binding and down-regulation by Na+ and K+ 1. J. Immunol. 155:2652.[Abstract]
  26. MacDonald, S. M., T. Rafnar, J. Langdon, L. M. Lichtenstein. 1995. Molecular identification of an IgE-dependent histamine-releasing factor. Science 269:688.[Abstract/Free Full Text]
  27. White, M. V., A. P. Kaplan, M. Haak-Frendscho, M. Kaliner. 1988. Neutrophils and mast cells: comparison of neutrophil-derived histamine-releasing activity with other histamine-releasing factors. J. Immunol. 141:3575.[Abstract]
  28. Ranadive, N. S., D. H. Ruben. 1977. Mast cell-lysosomal cationic protein interaction: use of 1-anilinonaphthalene-8-sulfonate as a fluorescent probe. Immunochemistry 14:165.[Medline]
  29. Lehrer, R. I., T. Ganz, M. E. Selsted. 1991. Defensins: Endogenous antibiotic peptides of animal cells. Cell 64:229.[Medline]
  30. Lehrer, R. I., A. K. Lichtenstein, T. Ganz. 1993. Defensins: antimicrobial and cytotoxic peptides of mammalian cells. Adv. Immunol. 11:105.
  31. Schonwetter, B. S., E. D. Stolzenberg, M. A. Zasloff. 1995. Epithelial antibiotics induced at sites of inflammation. Science 267:1645.[Abstract/Free Full Text]
  32. Zhu, Q., A. Bateman, A. Singh, S. Solomon. 1989. Isolation and biological activity of corticostatic peptides (anti-ACTH). Endocr. Res. 15:129.[Medline]
  33. Singh, A., A. Bateman, Q. Zhu, S. Shimasaki, F. Esch, S. Solomon. 1988. Structure of a novel human granulocyte peptide with anti-ACTH activity. Biochem. Biophys. Res. Commun. 155:524.[Medline]
  34. Territo, M. C., T. Ganz, M. E. Selsted, R. Lehrer. 1989. Monocyte-chemotactic activity of defensins from human neutrophils. J. Clin. Invest. 84:2014.
  35. Yamashita, T., K. Saito. 1989. Purification, primary structure, and biological activity of guinea pig neutrophil cationic peptides. Infect. Immun. 57:2405.[Abstract/Free Full Text]
  36. Shore, P. A., A. Burkhalter, Jr V. H. Cohn. 1959. A method for the fluorometric assay of histamine in tissues. J. Pharmacol. Exp. Ther. 127:182.[Abstract/Free Full Text]
  37. Zhu, Q., A. Singh, A. Bateman, F. Esch, S. Solomon. 1987. The corticostatic (anti-ACTH) and cytotoxic activity of peptides isolated from fetal, adult and tumor-bearing lung. J. Steroid Biochem. 27:1017.[Medline]
  38. Hu, J., H. P. Bennett, C. Lazure, S. Solomon. 1991. Isolation and characterization of corticostatic peptides from guinea pig bone marrow. Biochem. Biophys. Res.Commun. 180:558.[Medline]
  39. Bateman, A., A. Singh, S. Jothy, R. Fraser, F. Esch, S. Solomon. 1992. The levels and biologic action of the human neutrophil granule peptide HP-1 in lung tumors. Peptides 13:133.[Medline]
  40. Singh, A., A. Bateman, Q. Zhu, S. Shimasaki, F. Esch, S. Solomon. 1988. Structure of a novel human granulocyte peptide with anti-ACTH activity. Biochem. Biophys. Res. Commun. 155:524.
  41. Kokryakov, V. N., S. S. L. Harwig, E. A. Panyutich, A. A. Shevchenko, G. N. Aleshina, O. V. Shamova, H. A. Korneva, R. I. Lehrer. 1993. Protegrins: leukocyte antimicrobial peptides that combine features of corticostatic defensins and tachyplesins. FEBS Lett. 327:231.[Medline]
  42. Bueb, J. L., M. Mousli, Y. Landry, C. Bronner. 1990. A pertussis toxin-sensitive G protein is required to induce histamine release from rat peritoneal mast cells by bradykinin. Agents Actions 30:98.[Medline]
  43. Coleman, J. W., Q. Huang, D. R. Stanworth. 1986. The mast cell response to substance P: effects of neuraminidase, limulin, and some novel synthetic peptide antagonists. Peptides 7:171.[Medline]
  44. Lacy, P., N. Thompson, M. Tian, R. Solari, I. Hide, T. M. Newman, B. D. Gomperts. 1995. A survey of GTP-binding proteins and other potential key regulators of exocytotic secretion in eosinophils: apparent absence of rab3 and vesicle fusion protein homologues. J. Cell Sci. 108:3547.[Abstract]
  45. Gierschik, P., T. Bouillon, K.H. Jakobs. 1994. Receptor-stimulated hydrolysis of guanosine 5'-triphosphate in membrane preparations. Methods Enzymol. 237:13.[Medline]
  46. Nakamura, T., M. Ui. 1985. Simultaneous inhibitions of inositol phospholipid breakdown, arachidonic acid release, and histamine secretion in mast cells by islet-activating protein, pertussis toxin: a possible involvement of the toxin-specific substrate in the Ca2+-mobilizing receptor-mediated biosignaling system. J. Biol. Chem. 260:3584.[Abstract/Free Full Text]
  47. Saito, H., F. Okajima, T. F. P. Molski, R. I. Sha’afi, M. Ui, T. Ishizaka. 1987. Effects of ADP-ribosylation of GTP-binding protein by pertussis toxin of immunoglobulin E-dependent and -independent histamine release from mast cells and basophils. J. Immunol. 138:3927.[Abstract]
  48. Penner, R.. 1988. Multiple signaling pathways control stimulus-secretion coupling in rat peritoneal mast cells. Proc. Natl. Acad. Sci. USA 85:9856.[Abstract/Free Full Text]
  49. Stead, R. H., M. Tomioka, G. Quionez, G. T. Simon, S. Y. Felten, J. Bienenstock. 1987. Intestinal mucosal mast cells in normal and nematode-infected rat intestines are in intimate contact with peptidergic nerves. Proc. Natl. Acad. Sci. USA 84:2957.
  50. Janecka, A., T. Janecki, C. Y. Bowers, K. Folkers. 1994. New, highly active antagonists of LHRH with acylated lysine and p-aminophenylalanine in positions 5 and 6. Int. J. Pept. Protein Res. 44:19.[Medline]
  51. Jasani, B., G. Kreil, B. F. Mackler, D. R. Stanworth. 1979. Further studies on the structural requirements for polypeptide-mediated histamine release from rat mast cells. Biochem. J. 181:623.[Medline]
  52. Hanson, J. M., J. Morley, C. Soria-Herrera. 1974. Anti-inflammatory property of 401 MCD-peptide, a peptide from the venom of the bee Apis mellifera (L.). Br. J. Pharmacol. 50:383.[Medline]
  53. Kubota, Y.. 1992. The effect of human anaphylatoxins and neutrophils on histamine release from isolated human skin mast cells. J. Dermatol. 19:19.[Medline]
  54. Ganz, T., M. E. Selsted, D. Szklarek, S. S. L. Harwig, K. Daher, D. F. Bainton, R. I. Lehrer. 1985. Defensins: natural peptide antibiotics of human neutrophils. J. Clin. Invest. 76:1427.
  55. Wilde, C. G., J. E. Griffith, M. N. Marra, J. L. Snable, R. W. Scott. 1989. Purification and characterization of human neutrophil peptide 4, a novel member of the defensin family. J. Biol. Chem. 264:11200.[Abstract/Free Full Text]
  56. Mahida, Y. R., F. Rose, W.C. Chan. 1997. Antimicrobial peptides in the gastrointestinal tract. Gut 40:161.[Free Full Text]
  57. Kagan, B., M. E. Selsted, T. Ganz, R. I. Lehrer. 1990. Antimicrobial defensin peptides form-dependent ion-permeable channels in planar lipid bilayer membranes. Proc. Natl Acad. Sci. USA 87:210.[Abstract/Free Full Text]
  58. Cross, L. J., M. Ennis, E. Krause, M. Dathe, D. Lorenz, G. Krause, M. Beyermann, M. Bienert. 1995. Influence of {alpha}-helicity, amphipathicity and D-amino acid incorporation on the peptide-induced mast cell activation. Eur. J. Pharmacol. 291:291.[Medline]
  59. Yano, H., B. K. Wershil, N. Arizono, S. J. Galli. 1989. Substance P-induced augmentation of cutaneous vascular permeability and granulocyte infiltration in mice is mast cell dependent. J. Clin. Invest. 84:1276.
  60. Zhang, Y., B. F. Ramos, B. A. Jakschik. 1992. Neutrophil recruitment by tumor necrosis factor from mast cells in immune peritonitis. Science 258:1957.[Abstract/Free Full Text]
  61. Echtenacher, B., D. N. Mannel, L. Hultner. 1996. Critical protective role of mast cells in a model of acute septic peritonitis. Nature 381:75.[Medline]
  62. Malaviya, R., T. Ikeda, E. Ross, S. N. Abraham. 1996. Mast cell modulation of neutrophil influx and bacterial clearance at sites of infection through TNF-{alpha}. Nature 381:77.[Medline]
  63. Shaoheng, H., Q. Peng, A. Walls. 1997. Potent induction of a neutrophil and eosinophil-rich infiltrate in vivo by human mast cell tryptase: selective enhancement of eosinophil recruitment by histamine. J. Immunol. 159:6216.[Abstract]
  64. Huang, C., D. S. Friend, W.-T. Qiu, G. W. Wong, G. Morales, J. Hunt, R. L. Stevens. 1998. Induction of a selective and persistent extravasation of neutrophils into the peritoneal cavity by tryptase mouse mast cell protease 6. J. Immunol. 160:1910.[Abstract/Free Full Text]
  65. Shiomi, K., M. Nakazato, T. Ihi, K. Kangawa, H. Matsuo, S. Matsukura. 1993. Establishment of radioimmunoassay for human neutrophil peptides and their increases in plasma and neutrophils in infection. Biochem. Biophys. Res. Commun. 195:1336.[Medline]
  66. Panyutich, A. V., E. A. Panyutich, V. A. Krapivin, E. A. Baturevich, T. Ganz. 1993. Plasma defensin concentrations are elevated in patients with septicemia or bacterial meningitis. J. Lab. Clin. Med. 122:202.[Medline]
  67. Soong, L. B., T. Ganz, A. Ellison, G. H. Caughey. 1997. Purification and characterization of defensins from cystic fibrosis sputum. Inflamm. Res. 46:98.[Medline]
  68. Ashitani, J., H. Mukae, M. Nakazato, H. Taniguchi, K. Ogawa, S. Kohno, S. Matsukura. 1998. Elevated pleural fluid levels of defensins in patients with empyema. Chest 113:788.[Abstract/Free Full Text]
  69. Tominaga, T., J. Fukata, Y. Hayashi, N. Y Satoh, H. Fuse, O. Segawa, Y. Ebisui, Y. Osamura Nakai, H. Imura. 1992. Distribution and characterization of immunoreactive corticostatin in the hypothalamic-pituitary-adrenal axis. Endocrinology 130:1593.[Abstract/Free Full Text]
  70. Borenstein, L. A., T. Ganz, S. Sell, R. I. Lehrer, J. N. Miller. 1991. Contribution of rabbit leukocyte defensins to the host response in experimental syphilis. Infect. Immun. 59:1368.[Abstract/Free Full Text]
  71. Chertov, O., D. F. Michiel, L. Xu, J. M. Wang, K. Tani, W. J. Murphy, D. L. Longo, D. D. Taub, J. J. Oppenheim. 1996. Identification of defensin-1, defensin-2, and CAP37/azurocidin as T-cell chemoattractant proteins released from interleukin-8-stimulated neutrophils. J. Biol. Chem. 271:2935.[Abstract/Free Full Text]



This article has been cited by other articles:


Home page
 Antimicrob. Agents Chemother.Home page
Y. Okuyama-Nishida, N. Akiyama, G. Sugimori, K. Nomura, K. Ogawa, K. J. Homma, K. Sekimizu, M. Tsujimoto, and S. Natori
Prevention of Death in Bacterium-Infected Mice by a Synthetic Antimicrobial Peptide, L5, through Activation of Host Immunity
Antimicrob. Agents Chemother., June 1, 2009; 53(6): 2510 - 2516.
[Abstract] [Full Text] [PDF]

Home page
 JDRHome page
G. Diamond, N. Beckloff, and L.K. Ryan
Host Defense Peptides in the Oral Cavity and the Lung: Similarities and Differences
Journal of Dental Research, October 1, 2008; 87(10): 915 - 927.
[Abstract] [Full Text] [PDF]

Home page
 J. Leukoc. Biol.Home page
A. Biragyn, M. Coscia, K. Nagashima, M. Sanford, H. A. Young, and P. Olkhanud
Murine {beta}-defensin 2 promotes TLR-4/MyD88-mediated and NF-{kappa}B-dependent atypical death of APCs via activation of TNFR2
J. Leukoc. Biol., April 1, 2008; 83(4): 998 - 1008.
[Abstract] [Full Text] [PDF]

Home page
 Antimicrob. Agents Chemother.Home page
L. C. Huang, R. L. Redfern, S. Narayanan, R. Y. Reins, and A. M. McDermott
In Vitro Activity of Human {beta}-Defensin 2 against Pseudomonas aeruginosa in the Presence of Tear Fluid
Antimicrob. Agents Chemother., November 1, 2007; 51(11): 3853 - 3860.
[Abstract] [Full Text] [PDF]

Home page
 J. Immunol.Home page
J. Grigat, A. Soruri, U. Forssmann, J. Riggert, and J. Zwirner
Chemoattraction of Macrophages, T Lymphocytes, and Mast Cells Is Evolutionarily Conserved within the Human {alpha}-Defensin Family
J. Immunol., September 15, 2007; 179(6): 3958 - 3965.
[Abstract] [Full Text] [PDF]

Home page
 J. Leukoc. Biol.Home page
K. Tokita, Y. Uchida, and T. Yamamoto
Roles of leukocytosis and cysteinyl leukotriene in polymorphonuclear leukocyte-dependent plasma extravasation
J. Leukoc. Biol., December 1, 2006; 80(6): 1308 - 1319.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
C. B. Buck, P. M. Day, C. D. Thompson, J. Lubkowski, W. Lu, D. R. Lowy, and J. T. Schiller
Human {alpha}-defensins block papillomavirus infection
PNAS, January 31, 2006; 103(5): 1516 - 1521.
[Abstract] [Full Text] [PDF]

Home page
 Antimicrob. Agents Chemother.Home page
J. Varkey and R. Nagaraj
Antibacterial Activity of Human Neutrophil Defensin HNP-1 Analogs without Cysteines
Antimicrob. Agents Chemother., November 1, 2005; 49(11): 4561 - 4566.
[Abstract] [Full Text] [PDF]

Home page
 CVIHome page
T. Okamoto, T. Tanida, B. Wei, E. Ueta, T. Yamamoto, and T. Osaki
Regulation of Fungal Infection by a Combination of Amphotericin B and Peptide 2, a Lactoferrin Peptide That Activates Neutrophils
Clin. Vaccine Immunol., November 1, 2004; 11(6): 1111 - 1119.
[Abstract] [Full Text] [PDF]

Home page
 J. Leukoc. Biol.Home page
O. Levy
Antimicrobial proteins and peptides: anti-infective molecules of mammalian leukocytes
J. Leukoc. Biol., November 1, 2004; 76(5): 909 - 925.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
S. Narayanan, W. L. Miller, and A. M. McDermott
Expression of Human {beta}-Defensins in Conjunctival Epithelium: Relevance to Dry Eye Disease
Invest. Ophthalmol. Vis. Sci., September 1, 2003; 44(9): 3795 - 3801.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
A. M. McDermott, R. L. Redfern, B. Zhang, Y. Pei, L. Huang, and R. J. Proske
Defensin Expression by the Cornea: Multiple Signalling Pathways Mediate IL-1{beta} Stimulation of hBD-2 Expression by Human Corneal Epithelial Cells
Invest. Ophthalmol. Vis. Sci., May 1, 2003; 44(5): 1859 - 1865.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Pathol.Home page
C. A. Muller, J. Markovic-Lipkovski, T. Klatt, J. Gamper, G. Schwarz, H. Beck, M. Deeg, H. Kalbacher, S. Widmann, J. T. Wessels, et al.
Human {alpha}-Defensins HNPs-1, -2, and -3 in Renal Cell Carcinoma : Influences on Tumor Cell Proliferation
Am. J. Pathol., April 1, 2002; 160(4): 1311 - 1324.
[Abstract] [Full Text] [PDF]

Home page
 J. Leukoc. Biol.Home page
D. Yang, O. Chertov, and J. J. Oppenheim
Participation of mammalian defensins and cathelicidins in anti-microbial immunity: receptors and activities of human defensins and cathelicidin (LL-37)
J. Leukoc. Biol., May 1, 2001; 69(5): 691 - 697.
[Abstract] [Full Text]

Home page
 J. Leukoc. Biol.Home page
A. Risso
Leukocyte antimicrobial peptides: multifunctional effector molecules of innate immunity
J. Leukoc. Biol., December 1, 2000; 68(6): 785 - 792.
[Abstract] [Full Text]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Befus, A. D.
Right arrow Articles by Bateman, A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Befus, A. D.
Right arrow Articles by Bateman, A.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS