Relationship between eosinophilia and levels of chemokines (CCL5 and CCL11) and IL-5 in bronchoalveolar lavage fluid of patients with mustard gas-induced pulmonary fibrosis

OBJECTIVE

Therefore, this study was designed to analyze the bronchoalveolar lavage (BAL) fluid concentrations of IL-5, RANTES (CCL5) and eotaxin (CCL11) and also to examine the relationship between the percentage and absolute number of the BAL eosinophils and these measured chemokines in patients with sulfur mustard (SM) gas-induced pulmonary fibrosis (PF).

PATIENTS

Fifteen veterans with mustard gas-induced PF and 14 normal veterans as control group.

INTERVENTION

Pulmonary function tests, tests for D(LCO), computed tomography scans of the chest, analyses of BAL fluids for RANTES (CCL5), eotaxin (CCL11), and IL-5 were performed in all cases.

RESULTS

Eosinophilic alveolitis was the predominant feature (p < 0.0001). There were significant differences in CCL5, CCL11, and IL-5 levels of BAL fluid between patients with PF and controls (p < 0.0001, p < 0.0001, and p = 0.001, respectively). The concentrations of CCL5 and CCL11 showed positive correlations with percentage (r = 0.57 and p = 0.03; r = 0.52 and p = 0.04, respectively) and absolute counts (r = 0.54 and p = 0.04, r = 0.53 and p = 0.04, respectively) of BAL eosinophils. There were significant positive correlations between the concentrations of IL-5 and the proportion and total cell number of eosinophils in BAL (r = 0.67 and p = 0.01; r = 0.59 and p = 0.02, respectively) too.

CONCLUSION

A significant correlation between BAL CCL5, CCL11, and IL-5 levels and eosinophils in patients with pulmonary fibrosis due to SM gas inhalation has been demonstrated, suggesting that these C-C chemokines and IL-5 contribute to the recruitment of eosinophils cells in the lung in these victims.

Dengue viruses can infect human primary lung epithelia as well as lung carcinoma cells, and can also induce the secretion of IL-6 and RANTES

Dengue viruses (DENV) are herein demonstrated for the first time as being able to infect and replicate in human primary lung epithelium and various lung cancer cell lines. The detection of dengue virus particles and viral negative strand RNA synthesis in the cell, in conjunction with the release of viral progenies in culture supernatants, support the notion that lung cells are susceptible to dengue virus infection. The replication efficiency of DENV in lung cancer cells from high to low is: DEN-2 (dengue virus type-2), DEN-3, DEN-4 and DEN-1. Moreover, the susceptibility of the six lung cancer cell lines to DEN-2 infection is: SW1573>A549>H1435; H23; H520; Bes2B. DEN-2 infection significantly increased the expression levels of IL-6 and RANTES in four of the six lung cancer cell lines, which is consistent with the high expression levels of these molecules in DHF/DSS patients. IL-6 expression induced by DEN-2 infection was NF-kappaB dependent. In summary, our results indicate that lung epithelial cell is a possible target of dengue viruses and IL-6 and RANTES may play pivotal roles in lung related immuno-pathogenesis.

[Study of the mechanism of mast cell increase in cellular leiomyoma of uterus]

OBJECTIVE

To study the mechanism of mast cell increase in cellular leiomyoma of uterus.

METHODS

Tissue sections from 30 cases of cellular leiomyoma of uterus, 15 cases of leiomyosarcoma and 30 cases of ordinary leiomyoma were studied using immunohistochemical double labeling techniques. The expression of mast cell tryptase and Ki-67 as well as mast cell tryptase and chemotactic factors RANTES, Eotaxin, monocyte chemoattractant protein-1 (MCP-1), transforming growth factor-beta (TGF-beta) were double immunostained.

RESULTS

Ki-67 in mast cells was rarely expressed in each group. Expressions of regulate upon activation normal T cell expressed and secreted (RANTES), Eotaxin and TGF -beta in cellular leiomyoma were 78%, 89%, 91%, respectively. They were all higher than those in ordinary leiomyoma and leiomyosarcoma (P < 0.01), which were 60%, 81%, 86% and 39%, 44%, 59%, respectively. There were positive correlations between RANTES and the number of mast cells (r = 0.655, P < 0.01) as well as between Eotaxin and the number of mast cells (r = 0.543, P < 0.01). However, expression of MCP-1 was not observed in tumor cells in any group.

CONCLUSIONS

Mast cell increase in cellular leiomyoma of the uterus is due to local recruitment of mast cells. RANTES and Eotaxin secreted by smooth muscle tumor cells correlates with the recruitment of mast cells, but MCP-1 and TGF-beta do not.

Serum levels of the Th1 promoter IL-12 and the Th2 chemokine TARC are elevated in erythema multiforme and Stevens-Johnson syndrome/toxic epidermal necrolysis and correlate with soluble Fas ligand expression. An immunoenzymatic study from the Italian Group of Immunopathology

BACKGROUND

No data exist as to Th2 chemokines in erythema multiforme (EM) and Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN).

OBJECTIVE

To evaluate thymus- and activation-regulated chemokine (TARC), macrophage-derived chemokine (MDC) and regulated upon activation, normal T-lymphocyte-expressed and secreted chemokine (RANTES) expression in EM and SJS/TEN and to correlate with the serum levels of the Th1 promoter interleukin (IL)-12 and soluble Fas ligand (sFasL).

MATERIALS AND METHODS

IL-12, sFasL, TARC, MDC and RANTES expression were analyzed by ELISA techniques in 31 untreated EM (n = 24) or SJS/TEN (n = 7) patients and in 28 healthy donors (HD).

RESULTS

EM and SJS/TEN exhibited significantly higher levels of TARC, IL-12 and sFasL with respect to HD. TARC upregulation paralleled both the IL-12 (p = 0.0225) and sFasL increase (p = 0.0194).

CONCLUSIONS

Our results support a role of TARC in the pathophysiology of EM/SJS/TEN and confirm the coexistence of a Th2 response in addition to the predominant Th1 profile.

Study of the role of CCR5 in a mouse model of intranasal challenge with Yersinia pestis

CCR5 is a chemokine receptor used by HIV-1 to enter cells and has recently been found to act as a pathogen associated molecule pattern receptor. Current positive selection for the high frequency of a CCR5-Delta32 allele in humans has been attributed to resistance to HIV, smallpox, and plague infections. Using an intranasal mouse model of Y. pestis infection, we have found that lack of CCR5 does not enhance host resistance to Y. pestis infection and that CCR5-mediated responses might have a protective role. CCR5-/- mice exhibited higher levels of circulating RANTES and MIP-1alpha than those exhibited by wild-type mice at the baseline and throughout the course of Y. pestis infection. High levels of RANTES and MIP-1alpha, which are CCR5 ligands that mediate Natural Killer cell migration, may reflect compensation for the absence of CCR5 signaling.

Differential regulation of chemokine expression by Th1 and Th2 cytokines and mechanisms of eotaxin/CCL-11 expression in human airway smooth muscle cells

BACKGROUND

Airway smooth muscle (ASM) cells may contribute to the pathogenesis of asthma including airway inflammation and remodeling. We focused our study on the regulation of chemokine expression by cytokines and analyzed the mechanisms of eotaxin/CCL-11 expression in ASM cells.

METHODS

Human ASM cells were cultured in vitro and treated with IL-4, interferon-gamma (IFNgamma), and tumor necrosis factor-alpha (TNFalpha). Secretion of chemokines into the culture medium was analyzed by ELISA. Expression of eotaxin mRNA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Binding of transcription factor signal transducer activator of transcription (STAT) 6 to the eotaxin promoter-derived DNA was analyzed by pull-down Western blot. To assess transcriptional regulation of eotaxin, cells were transfected with eotaxin promoter-luciferase reporter plasmids, and activity was determined by dual luciferase assay.

RESULTS

The Th2 cytokine IL-4 preferentially stimulated the expression of the CC chemokine receptor (CCR) 3-ligand chemokines eotaxin, eotaxin-3, and MCP-4. The Th1 cytokine IFNgamma stimulated the expression of chemokines IP-10 and RANTES. IL-4 stimulated nuclear translocation of signal transducer activator of transcription 6 (STAT6) and its binding to the eotaxin promoter region. IL-4 activated the eotaxin promoter and its activity was inhibited by mutation of the binding site for STAT6 in the promoter.

CONCLUSIONS

The Th2 cytokine IL-4 preferentially stimulated the expression of CCR3 ligand chemokines including eotaxin in ASM cells. The transcription factor STAT6 may play a pivotal role in the activation of eotaxin transcription in response to IL-4.

Differential regulation of RANTES and IL-8 expression in lung adenocarcinoma cells

In lung adenocarcinoma, expression of Regulated upon Activation, Normal T cell Expressed and presumably Secreted (RANTES) is a predictor of survival while that of interleukin (IL)-8 is associated with a poor prognosis. In several models, tumorigenesis is abolished by RANTES, while it is facilitated by IL-8. We studied the regulation of RANTES and IL-8 expression in A549 lung adenocarcinoma cells. The effects of tumor necrosis factor (TNF)-alpha and regulators of protein kinases C (PKC)alpha/beta were tested because these have been shown to modulate cancer development and progression. TNF-alpha stimulated expression of both chemokines, while the PKCalpha/beta activator 12-O-tetradecanoyl-phorbol-13-acetate (TPA) induced only expression of IL-8 and inhibited TNF-alpha-induced RANTES expression. The PKCalpha/beta inhibitor Gö 6976 increased TNF-alpha-induced RANTES production and prevented its down-regulation by TPA. In contrast, it decreased TNF-alpha or TPA-induced IL-8 release. The differential regulation of RANTES and IL-8 expression was further analyzed. Site-directed mutagenesis indicated that regulation of RANTES promoter activity required two nuclear factor (NF)-kappaB response elements but not its activator protein (AP)-1 binding sites. An AP-1 and a NF-kappaB recognition sites were necessary for full induction of IL-8 promoter activity by TNF-alpha and TPA. Moreover, electrophoretic mobility shift assays demonstrated that NF-kappaB response elements from the RANTES promoter were of lower affinity than that from the IL-8 promoter. Immunoblotting experiments showed that TPA was more potent than TNF-alpha to induce in a PKCalpha/beta dependent manner the p44/p42 mitogen-activated protein kinases (MAPK) signaling cascade which controls AP-1 activity. Conversely, TPA inhibited TNF-alpha-induced NF-kappaB signaling and was a weak activator of this pathway. Thus, TPA did not sufficiently activate NF-kappaB to increase transcription through the low affinity NF-kappaB binding sites on RANTES promoter and its inhibitory effect on TNF-alpha-induced NF-kappaB signaling resulted in a reduced transcription rate. On IL-8 promoter, increased transcription through the high affinity NF-kappaB binding site occurred even with poorly activated NF-kappaB and the functional AP-1 response element compensated any loss of transcription rate. These data provide a mechanistic insight into the differential regulation of IL-8 and RANTES expression by PKCalpha/beta in lung adenocarcinoma cells.

Role of RIG-I, MDA-5, and PKR on the expression of inflammatory chemokines induced by synthetic dsRNA in airway epithelial cells

BACKGROUND

We hypothesized that synthetic double-stranded (ds)RNA may mimic viral infection and reported that dsRNA stimulates expression of inflammatory chemokines through a receptor of dsRNA Toll-like receptor (TLR) 3 in airway epithelial cells. In this study, we focused our study on the role of other receptors for dsRNA, such as retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated gene 5 (MDA-5), and double-stranded RNA-dependent protein kinase (PKR).

METHODS

Airway epithelial cell BEAS-2B was cultured in vitro. Expression of target RNA and protein were analyzed by PCR and ELISA. To analyze the role of receptors for dsRNA, knockdown of theses genes was performed with short interfering RNA (siRNA).

RESULTS

We first investigated the effects of chloroquine, an inhibitor of lysosomal acidification, on the expression of chemokines. Preincubation with 100 microM chloroquine significantly inhibited the expression of mRNA for RANTES, IP-10, and IL-8, stimulated by poly I:C, indicating that poly I:C may react with a receptor expressed inside the cells. RIG-I, MDA-5, and PKR are supposed to be expressed inside the airway epithelial cells. However, the expression of chemokines stimulated with poly I:C was not significantly inhibited for these putative receptors in the cells which were transfected with siRNA.

CONCLUSIONS

Synthetic dsRNA poly I:C stimulates the expression of inflammatory chemokines in airway epithelial cells, but the putative receptors for dsRNA such as RIG-I, MDA-5, or PKR may not play pivotal roles in this process. TLR3 may play a major role as reported previously.

Aberrant expression of the insulin-like growth factor-1 receptor by T cells from patients with Graves' disease may carry functional consequences for disease pathogenesis

Graves' disease (GD), an autoimmune process involving thyroid and orbital tissue, is associated with lymphocyte abnormalities including expansion of memory T cells. Insulin-like growth factor receptor-1 (IGF-1R)-bearing fibroblasts overpopulate connective tissues in GD. IGF-1R on fibroblasts, when ligated with IgGs from these patients, results in the expression of the T cell chemoattractants, IL-16 and RANTES. We now report that a disproportionately large fraction of peripheral blood T cells express IGF-1R (CD3+IGF-R+). CD3+IGF-1R+ T cells comprise 48 +/- 4% (mean +/- SE; n = 33) in patients with GD compared with 15 +/- 3% (n = 21; p < 10(-8)) in controls. This increased population of IGF-1R+ T cells results, at least in part, from an expansion of CD45RO+ T cells expressing the receptor. In contrast, the fraction of CD45RA+IGF-1R+ T cells is similar in GD and controls. T cells harvested from affected orbital tissues in GD reflect similar differences in the proportion of IGF-1R+CD3+ and IGF-1R+CD4+CD3+ cells as those found in the peripheral circulation. GD-derived peripheral T cells express durable, constitutive IGF-1R expression in culture and receptor levels are further up-regulated following CD3 complex activation. IGF-1 enhanced GD-derived T cell incorporation of BrdU (p < 0.02) and inhibited Fas-mediated apoptosis (p < 0.02). These findings suggest a potential role for IGF-1R displayed by lymphocytes in supporting the expansion of memory T cells in GD.

[Effects of progesterone and progestin on expression of regulated on activation, normal T cell expressed and secreted in eutopic endometrium from patients with endometriosis]

OBJECTIVE

To investigate the effects of progesterone and progestin on the expressions of regulated on activation, normal T cell expressed and secreted (RANTES) in eutopic endometrium from patients with endometriosis.

METHODS

We collected the samples of endometrium from patients with endometriosis before operation or after insertion of levenorgestrel releasing intrauterine system (LNG-IUS), administration of oral medroxyprogesterone (MPA), or injection of gonadotrophic hormone releasing hormone agonist (GnRHa). Reverse transcription-polymerase chain raction was used to assay the expression of RANTES mRNA. On the other hand, progesterone (Po) and tumor necrosis factor-alpha (TNFalpha) of different concentrations and different manners were used to treat cultured cells in vitro. RANTES secretion was evaluated in the culture medium using ELISA. In order to evaluate the effect of Po on the secretion of RANTES under stimulation of TNFalpha, the cells were cultured in medium containing 100 U/ml TNFalpha and Po of different concentrations for 24 hours. After the pretreatment of Po for 48 hours at different concentrations, TNFalpha (100 U/ml, 16 h) was added to observe whether Po inhibits RANTES or not.

RESULTS

The expression of RANTES mRNA in eutopic endometrium of patients with endometriosis was significantly higher than in control group (28.0 +/- 9.0 vs. 22.0 +/- 5.6, P < 0.05). Following the exposures to LNG-IUS (24.0 +/- 4.2 vs. 25.9 +/- 4.2, P > 0.05) or GnRHa (23.0 +/- 12.9 vs. 26.9 +/- 5.2, P > 0.05), the expression of RANTES mRNA had no change. MPA significantly increased the expression of RANTES mRNA (42.6 +/- 3.1 vs. 24.3 +/- 5.7, P < 0.05). Po itself had no significant effect on the secretion of RANTES. Stimulated by Po and TNFalpha at the same time, the secretion of RANTES significantly increased. After pretreatment with Po for 48 hours, the reaction of RANTES to the stimulating effect of TNFalpha was down-regulated.

CONCLUSION

The eutopic endometrium of patients with endometriosis has high chemotactic activity. It may be feasible to prevent and treat endometriosis with progestins.

Percutaneous application of peptidoglycan from Staphylococcus aureus induces eosinophil infiltration in mouse skin

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease with immunopathologic features that vary depending on the duration of the lesion. The lesioned skin of AD patients shows an increased number of inflammatory cells such as eosinophils, mast cells and mononuclear cells in the dermis and superficial Staphylococcus aureus colonization.

OBJECTIVE

The purpose of this study was to determine the effects of peptidoglycan (PEG) from S. aureus on eosinophil induction in murine skin.

METHODS

PEG was applied to the barrier-disrupted abdominal skin of mice every 5 days. Twenty days later, the number of eosinophils in the abdominal skin was counted. The cytokine response in the skin was investigated by RT-PCR and immunohistological analysis. The regulated-upon activation in normal T cells expressed and secreted (RANTES) production from cultured epidermal cells was measured by ELISA.

RESULTS

The skin of mice treated with PEG showed a significantly increased number of eosinophils compared with that of mice treated with vehicle alone. In addition, application of PEG to the abdominal skin of mice increased the expression of mRNA for RANTES, but not that of mRNA for eotaxin, eotaxin-2 and monocyte chemotactic protein-3 in the skin. Immunohistologic analysis demonstrated that the levels of RANTES transcripts corresponded with those of protein synthesis in the epidermis. In vitro experiments using epidermal Langerhans cells (LCs) and keratinocytes (KCs) showed that RANTES production was induced by LCs but not by KCs stimulated with PEG. Furthermore, an intraperitoneal injection of anti-RANTES antibody neutralized the induction of eosinophils in the skin.

CONCLUSION

These results suggest that PEG may have an ability to induce eosinophil infiltration in the skin through RANTES production by LCs, and would explain the role of S. aureus colonization in AD patients.

Induction of maternal tolerance to fetal alloantigens by RANTES production

PROBLEM

Previous studies have demonstrated a requirement for RANTES (regulated on activated normal T-cell expressed, and secreted) at immune privileged sites; we have investigated the role of RANTES in the induction of maternal-fetal tolerance.

METHOD OF STUDY

Endometrial and peripheral T lymphocytes were obtained from women with recurrent pregnancy losses (RPLs) and fertile women. RANTES modulation by progesterone or paternal alloantigens was measured by enzyme-linked immunosorbent assay or flow cytometry analysis.

RESULTS

Progesterone significantly increased intracellular RANTES expression in CD4+ and CD8+ endometrial T cells. Moreover, alloreactive lymphocytes from RPL patients produced lower RANTES levels when compared with those from fertile women. At the local level, treatment with recombinant RANTES induced a decrease in CCR5 and CXCR4 messenger RNA that correlated with an increase in T-bet expression. RPL patients and normally fertile women express RANTES similarly, but differ in their patterns of RANTES receptor expression.

CONCLUSION

RANTES may be implicated in the local induction of a Th1-type response necessary for successful implantation. Altered response to RANTES stimulation among some RPL patients may be responsible for poor pregnancy outcomes.

Nicotine and Lipopolysaccharide Affect Cytokine Expression From Gingival Fibroblasts

BACKGROUND

This in vitro study investigated the influence of nicotine, lipopolysaccharide (LPS), and a combination of both agents on cytokine expression from human gingival fibroblasts (HGFs).

METHODS

HGFs were exposed for 48 hours to 250 microg/ml nicotine, 1 microg/ml Porphyromonas gingivalis LPS, or both. The expression of multiple cytokines was detected in the HGFs conditioned media using cytokine protein arrays.

RESULTS

The untreated HGFs expressed several cytokines, which included relatively high levels of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1). They also expressed low levels of growth-regulated oncogene (GRO), IL-3, and IL-10. Nicotine had the greatest effect on the expression of GRO-alpha, IL-7, IL-10, and IL-15 compared to the untreated control. P. gingivalis LPS had the greatest effect on the expression of GRO-alpha; IL-7; IL-10; and RANTES (regulated on activation, normal T-cell expressed, and presumably secreted) compared to the untreated control. The combination of both agents had the biggest impact on the expression of GRO-alpha, IL-7, IL-10, IL-15, RANTES, and interferon-gamma (IFN-gamma) compared to the untreated control.

CONCLUSION

HGFs exposed to nicotine, P. gingivalis LPS, or a combination of both agents increased the expression of multiple cytokines.

Cytokine induction by respiratory syncytial virus and adenovirus in bronchial epithelial cells

In order to broaden our knowledge of the primary immune responses to respiratory syncytial virus (RSV) and adenovirus infections, we compared the concentrations of interleukin (IL)-6, IL-8, and regulated on activation, normal T cell expressed and secreted (RANTES) produced in vitro during RSV and adenovirus infections of bronchial epithelial cells. We infected BEAS-2B cells-a human bronchial epithelial cell line-with RSV, adenovirus serotype 3, or serotype 7 and measured the concentrations of IL-6, IL-8, and RANTES in the cell culture supernatants. When the multiplicity of infection (MOI) was 1, RSV induced the production of markedly higher concentrations of IL-6, IL-8, and RANTES than the adenovirus. When the MOI of the adenovirus was increased to 100, the production of IL-6 and IL-8 increased. However, the amounts produced were still lower than those produced by RSV with the MOI of 1. There was no statistically significant increase in the production of RANTES in spite of the MOI of the adenovirus was increased to 100. Adenovirus serotype 7 induced the production of considerably more IL-6 and IL-8 than serotype 3 in the MOI of 100. However, neither adenovirus serotype triggered an increase in the production of RANTES in spite of the MOI of 100. This demonstrates that RSV could have a superior capacity to stimulate the production of IL-6, IL-8, and RANTES in the bronchial epithelial cells. This study may help to explain the differences in the clinical outcomes of RSV and adenovirus infections.

Upregulating promoter polymorphisms of RANTES relate to atopic dermatitis

It has been reported that a functional polymorphism in the promoter of the RANTES gene (-403G/A) is associated with atopic dermatitis in a German population. Although there are several reports on the association of RANTES promoter polymorphisms (-403G/A and -28C/G) with asthma, the association of these polymorphisms with atopic dermatitis has not yet been confirmed in other populations. We therefore aimed to test whether the RANTES promoter polymorphisms relate to atopic dermatitis in a well-defined Japanese population. We conducted an association study of upregulating promoter polymorphisms of RANTES (-403G/A and -28C/G) in 389 patients with atopic dermatitis and 177 healthy control subjects. There was a significant association between the upregulating variant of RANTES -28G and atopic dermatitis, while -403A variant showed a significant association with atopic dermatitis with high IgE productivity. These results support a role for RANTES promoter polymorphisms in susceptibility to atopic dermatitis.

The significant role of RANTES and CCR5 in progressive tubulointerstitial lesions in lupus nephropathy

Glomerulonephritis is an important cause of end-stage renal failure, yet the pathogenetic mechanisms of most forms of glomerulonephritis are not clear. Renal fibrosis is the final common pathway for many kidney lesions that lead to chronic progressive organ failure. Recent study suggests that chemokines and chemokine receptors are involved in the resolution or progression of renal diseases. In view of the above we detected using immunohistochemistry the expression of RANTES, CCR5+ cells,TGF-beta1, alpha-SMA in renal biopsy specimens in 17 patients with IVG A/C class of lupus nephritis and in 10 normal kidneys. The correlative study was undertaken to evaluate the possible relationships between the immunoexpression of RANTES, the number of CCR5+ cells, the immunoexpression of TGF-beta1, alpha-SMA, the value of interstitial cortical volume and the serum creatinine level in patients with lupus nephropathy. Statistical analysis revealed significant increase in tubulointerstitial RANTES immunoexpression in lupus nephritis as compared to normal controls. In our study CCR5+ cells were detected in the interstitium in tissue samples in patient with lupus nephritis, meanwhile no CCR5+ cells were documented in normal controls. We found a strong positive correlation between tubulointerstitial immunoexpression of RANTES and the number of interstitial CCR5+ cells as well as between immunoexpression of RANTES and the immunoexpression of TGF-beta1, alpha-SMA, renal cortical volume and serum creatinine in patients with lupus nephritis. Moreover, the number of interstitial CCR5+ cells was positively correlated with tubulointerstitial alpha-SMA immunoexpression and renal cortical volume. In summary, the results suggest that in lupus nephritis RANTES may participate in interstitial lesions via CCR5+ cells.

Burkholderia mallei expresses a unique lipopolysaccharide mixture that is a potent activator of human Toll-like receptor 4 complexes

Burkholderia mallei, the aetiologic agent of glanders, causes a variety of illnesses in animals and humans ranging from occult infections to acute fulminating septicaemias. To better understand the role of lipopolysaccharide (LPS) in the pathogenesis of these diseases, studies were initiated to characterize the structural and biological properties of lipid A moieties expressed by this organism. Using a combination of chemical analyses and MALDI-TOF mass spectrometry, B. mallei was shown to express a heterogeneous mixture of tetra- and penta-acylated lipid A species that were non-stoichiometrically substituted with 4-amino-4-deoxy-arabinose residues. The major penta-acylated species consisted of bisphosphorylated d-glucosamine disaccharide backbones possessing two amide linked 3-hydroxyhexadecanoic acids, two ester linked 3-hydroxytetradecanoic acids [C14:0(3-OH)] and an acyloxyacyl linked tetradecanoic acid, whereas, the major tetra-acylated species possessed all but the 3'-linked C14:0(3-OH) residues. In addition, although devoid of hexa-acylated species, B. mallei LPS was shown to be a potent activator of human Toll-like receptor 4 complexes and stimulated human macrophage-like cells (THP-1 and U-937), monocyte-derived macrophages and dendritic cells to produce high levels of TNF-alpha, IL-6 and RANTES. Based upon these results, it appears that B. mallei LPS is likely to play a significant role in the pathogenesis of human disease.

Upregulation of interferon-alpha and RANTES in the cervix of HIV-1-seronegative women with high-risk behavior

OBJECTIVE

The expression of innate immune molecules associated with potential blocking activity of HIV-1 propagation was analyzed in the cervical tissue of a group of African HIV-1 IgG-negative commercial sex workers (CSWs) with an HIV-1-encountering risk behavior.

METHODS

Cervical biopsies from the superior portion of the ectocervix were assessed for innate immune molecules and evaluated in situ by computerized image analysis at the single-cell level.

RESULTS

A higher expression of interferon-alpha (IFNalpha) and RANTES was detected in CSWs and HIV-1-infected individuals as compared to low-risk HIV-1-uninfected controls (Neg Ctrls). Most (>90%) of RANTES-expressing cells were CD8 cells as determined by confocal microscopy. In contrast, the expression of leukemia inhibitory factor (LIF) and secretory leukocyte protease inhibitor (SLPI) was comparable between the groups. The expression of beta-defensin 2 was highest in HIV-1-infected individuals.

CONCLUSIONS

Induction of IFNalpha and RANTES expression in cervical mucosa may contribute to protection of sexual HIV-1 transmission in subjects with a higher risk behavior.

Interleukin-17 is a negative regulator of established allergic asthma

T helper (Th)17 cells producing interleukin (IL)-17 play a role in autoimmune and allergic inflammation. Here, we show that IL-23 induces IL-17 in the lung and IL-17 is required during antigen sensitization to develop allergic asthma, as shown in IL-17R–deficient mice. Since IL-17 expression increased further upon antigen challenge, we addressed its function in the effector phase. Most strikingly, neutralization of IL-17 augmented the allergic response in sensitized mice. Conversely, exogenous IL-17 reduced pulmonary eosinophil recruitment and bronchial hyperreactivity, demonstrating a novel regulatory role of IL-17. Mechanistically, IL-17 down modulated eosinophil-chemokine eotaxin (CCL11) and thymus- and activation-regulated chemokine/CCL17 (TARC) in lungs in vivo and ex vivo upon antigen restimulation. In vitro, IL-17 reduced TARC production in dendritic cells (DCs)—the major source of TARC—and antigen uptake by DCs and IL-5 and IL-13 production in regional lymph nodes. Furthermore, IL-17 is regulated in an IL-4–dependent manner since mice deficient for IL-4Rα signaling showed a marked increase in IL-17 concentration with inhibited eosinophil recruitment. Therefore, endogenous IL-17 is controlled by IL-4 and has a dual role. Although it is essential during antigen sensitization to establish allergic asthma, in sensitized mice IL-17 attenuates the allergic response by inhibiting DCs and chemokine synthesis.

Dynamic interplay of transcriptional machinery and chromatin regulates "late" expression of the chemokine RANTES in T lymphocytes

The chemokine RANTES (regulated upon activation normal T cell expressed and secreted) is expressed "late" (3 to 5 days) after activation in T lymphocytes. In order to understand the molecular events that accompany changes in gene expression, a detailed analysis of the interplay between transcriptional machinery and chromatin on the RANTES promoter over time was undertaken. Krüppel-like factor 13 (KLF13), a sequence-specific DNA binding transcription factor, orchestrates the induction of RANTES expression in T lymphocytes by ordered recruitment of effector molecules, including Nemo-like kinase, p300/cyclic AMP response element binding protein (CBP), p300/CBP-associated factor, and Brahma-related gene 1, that initiate sequential changes in phosphorylation and acetylation of histones and ATP-dependent chromatin remodeling near the TATA box of the RANTES promoter. These events recruit RNA polymerase II to the RANTES promoter and are responsible for late expression of RANTES in T lymphocytes. Therefore, KLF13 is a key regulator of late RANTES expression in T lymphocytes.

Targeting the NF-kappaB pathway through pharmacological inhibition of IKK2 prevents human cytomegalovirus replication and virus-induced inflammatory response in infected endothelial cells

Endothelial cells are important reservoirs for human cytomegalovirus (HCMV) replication, dissemination and persistence. HCMV infection of endothelial cells has been associated with a proinflammatory response characterized by an increased expression of chemokines and adhesion molecules and modulation of angiogenesis. Many of the host proinflammatory genes augmented in HCMV-infected endothelial cells are regulated, at least in part, by the NF-kappaB pathway. HCMV is a potent activator of NF-kappaB through the IKK-IkappaB signaling axis. To explore whether inhibition of HCMV-induced NF-kappaB activation may interfere with the onset of virus-associated inflammatory response, we measured the effects of the specific IKK2 inhibitor AS602868 on the expression of a panel of proinflammatory genes in HUVEC cells infected with a clinical isolate. Treatment of infected HUVEC with AS602868 was shown to impair HCMV-induced NF-kappaB activity, IE gene expression, viral replication and to prevent HCMV-induced upregulation of ICAM-1, IL-8, RANTES, IP-10, I-TAC and COX-2 gene expression. Consistent with these results, HCMV-mediated upregulation of another NF-kappaB-dependent gene, the plasminogen inhibitor type-1, a regulatory factor of endothelial proliferation and angiogenesis, was abrogated by AS602868. These results suggest that inhibition of HCMV-induced IKK-NF-kappaB activation may be of interest to limit the virus-induced inflammatory response of infected endothelial cells.

Recognition of RANTES by extracellular parts of the CCR5 receptor

The chemokine RANTES (regulated upon activation, normal T-cell expressed and secreted) is a natural ligand of CCR5, one of the major HIV-1 coreceptors. It is secreted as part of the immune response to human immunodeficiency virus 1 (HIV-1) and inhibits infection by CCR5-dependent (R5) HIV-1 isolates. We have investigated the interaction of RANTES with several peptides derived from the extracellular domains of CCR5 by heteronuclear NMR spectroscopy in aqueous solution. We show that a peptide comprising the first 25 amino acid residues of the CCR5 N-terminal domain and sulfated at the Y10 and Y14 side-chains binds with micromolar affinity exclusively to the monomeric form of RANTES. In contrast to the tight binding of the sulfated peptide, the affinity of the same peptide in non-sulfated form was reduced by more than two orders of magnitude. Peptides derived from the CCR5 extracellular loops ECL1, ECL2 and ECL3 showed only very moderate and mostly non-specific binding. Chemical shift mapping of the interaction of the sulfated N-terminal peptide reveals a contiguous binding surface on RANTES, which comprises amino acid residues of the first beta-strand, the N-loop, the fourth beta-strand and the turns around residues 30 and 40. This binding surface largely overlaps with the dimer interface and is strongly positively charged, providing a rationale for the exclusive binding of the monomer to the peptide and the requirement of the negative sulfate groups at the Y10 and Y14 side-chains. The binding surface also largely overlaps with the segments that were identified previously as crucial for HIV blockade by peptide scanning and mutagenesis studies. These data offer new insights into the structure-function relation of the RANTES-CCR5 interaction and may be helpful for the design of novel HIV-1 inhibitors.

Suppression of RANTES in children with Plasmodium falciparum malaria

Severe malarial anemia (MA) is the primary manifestation of severe malaria among children in areas of holoendemic Plasmodium falciparum transmission. Although overproduction of inflammatory-derived cytokines are implicated in the immunopathogenesis of severe MA, chemokines such as regulated on activation, normal T-cell expressed and secreted (RANTES, CCL5) are largely unexplored in childhood malaria. We found that RANTES is decreased during severe MA (p<0.01), and associated with suppression of erythropoiesis (p<0.05) and malaria-induced thrombocytopenia (p<0.05). These findings suggest that thrombocytopenia may be a source of reduced RANTES which may contribute, at least in part, to suppression of erythropoiesis in children with malarial anemia.

Systemic and local CC chemokines production in a murine model of Listeria monocytogenes infection

Repeated intragastric inoculation of Listeria monocytogenes into BALB/c mice resulted in prolonged bacteraemia and severe hepatic infection. Bacteria could also be isolated from the brain tissue of all experimental mice. During the inflammatory process, chemokine concentrations typically increased at the local site in comparison to the systemic level. The liver-to-serum ratio was more pronounced in the case of macrophage inflammatory protein 1α (MIP-1α), suggesting its role in the inflammatory response in the liver. The ratio of brain-to-serum concentration of monocyte chemoattractant protein 1 (MCP-1) remained the same as in the control animals, while it was lower in the infected mice, both in the case MIP-1α and in the case of regulated on activation, normal T cell expressed and secreted (RANTES). This is in correlation with slight inflammatory infiltrates found in the brain tissue early in infection.

Gastro-Intestinal Exposure to Latex Antigens Induce Allergic Responses in Mice

BACKGROUND

Natural rubber latex (NRL) has emerged as a major cause of respiratory allergy among specific exposed groups of individuals. Since latex allergens are dispersed in the environment it is conceivable that latex proteins are both inhaled and ingested. The mechanism of latex allergy and the immune responses following reexposure of latex allergens by the intranasal route was studied in a murine model of latex allergy developed by intragastric sensitization with NRL.

METHODS

BALB/c mice were sensitized intragastrically ('ig'), intranasally ('in') or 'ig' followed by 'in' challenge with NRL allergens. The cellular and humoral immune responses, lung function and histological changes were determined.

RESULTS

Peripheral blood eosinophilia was observed in the 'ig' and 'ig/in'-NRL-sensitized animals in comparison to normal controls (p < 0.05). The 'ig' group showed a marked increase over control mice in serum total IgE, NRL-specific IgG and IgG subclasses (p < 0.05). Increased levels of IL-4, IL-5, IL-10, and IL-13 were detected in 'ig'-NRL-sensitized mice. Intranasal exposure with NRL after 'ig' sensitization further enhanced the cytokine levels. A tendency towards enhanced stimulation was determined in 'ig'-sensitized mice; a significant difference was shown in the 'ig/in'-group (p < 0.05). Increased airway hyperreactivity was found in 'ig'-NRL-sensitized-mice (15.1 +/- 2.5 vs. 8.9 +/- 1.7 cm H2O x ml(-1) x s, p < 0.05). Mucus secretion from jejunal epithelium and eosinophilic infiltration into the jejunal lamina propria were observed in the 'ig'-NRL-sensitized-mice.

CONCLUSIONS

The results demonstrate that intragastric NRL sensitization did not induce specific tolerance, and additional intranasal exposure with latex allergens resulted in systemic allergic manifestations in the murine model.