Role of CCL21 and CCL19 in allergic inflammation in the ovalbumin-specific murine asthmatic model

BACKGROUND

Dendritic cells are the most powerful of the antigen-presenting cells and are known to play important roles in sensitization and inflammation in allergen-specific asthma. Various cytokines and chemokines are involved in the maturation and activation of dendritic cells. Among them is CC chemokine ligand (CCL)21, a key chemokine in the entry of naive T cells and antigen-stimulated dendritic cells into the T-cell zones of secondary lymphoid organs, which is a critical process in antigen-specific T-cell activation.

OBJECTIVE

We studied the role of CCL21 in airway inflammation in asthma by using BALB/c-plt/plt (plt) mice, which possess genetic defects in expression of both CCL21 and CCL19.

METHODS

Plt and control BALB/c mice were immunized with ovalbumin and alum 4 times and thereafter were subjected to a 2-week regimen of ovalbumin inhalation.

RESULTS

In plt mice, ovalbumin-specific IgE response was delayed compared with control BALB/c mice, but they had the same level of response after final immunization. Although airway inflammation and response to acetylcholine were significantly reduced compared with BALB/c mice, significant eosinophilic inflammation and hyperresponsiveness were also observed in plt mice after 2 weeks of inhalation. Four weeks after cessation of inhalation, airway inflammation and hyperresponsiveness in plt mice were greater than in BALB/c mice. At the time of resolution of airway inflammation, IL-10 production was enhanced in BALB/c mice but not in plt mice.

CONCLUSION

The chemokines CCL21 and CCL19 were critical for resolution of airway inflammation.

CLINICAL IMPLICATIONS

The findings about the chemokines for induction and resolution of inflammation are key to establishing a new strategy for asthma immunotherapy.

Persistent abnormalities in peripheral blood dendritic cells and monocytes from HIV-1-positive patients after 1 year of antiretroviral therapy

Antiretroviral therapy (ART) has led to marked decreases in morbidity and mortality rates among HIV-1-positive patients; however, immune recovery is not complete. Although dendritic cells (DCs) were shown to be involved in HIV-1 pathogenesis, few studies have investigated the effect of ART on DCs. We have analyzed the effect of ART on numerical distribution, expression of chemokine receptors, and ex vivo production of inflammatory cytokines by peripheral blood (PB) monocytes and DCs in a cohort of chronically infected HIV-1-positive patients. Patients were tested before therapy and at weeks +2, +4, +8, +12, and +52 after starting ART.Our results show an incomplete T-cell immune reconstitution in chronically infected patients who had undetectable plasma viremia while taking ART for 1 year. This was associated with persistent abnormalities at week +52 of ART, corresponding to increased numbers of CD16 DCs and monocytes, as well as altered expression of CXC chemokine receptors, in the form of increased CXCR1 expression on monocytes and decreased reactivity for CXCR2 and/or CXCR4 on myeloid and plasmacytoid DCs. In addition, an abnormally high spontaneous ex vivo secretion of inflammatory cytokines by CD16 DCs and monocytes was still detected after 1 year of ART. These abnormalities were especially pronounced in patients with less than 200 CD4 T cells/microL, which could be related to the persistence of undetected viral replication and sustained immune activation.

The CC Chemokine MCP-1 Stimulates Surface Expression of CX3CR1 and Enhances the Adhesion of Monocytes to Fractalkine/CX3CL1 via p38 MAPK

The membrane-anchored form of CX3CL1 has been proposed as a novel adhesion protein for leukocytes. This functional property of CX3CL1 is mediated through CX3CR1, a chemokine receptor expressed predominantly on circulating white blood cells. Thus far, it is still uncertain at what stage of the trafficking process CX3CR1 becomes importantly involved and how the CX3CR1-dependent adhesion of leukocytes is regulated during inflammation. The objective of this study was to examine the functional effects of chemokine stimulation on CX3CR1-mediated adhesion of human monocytes. Consistent with previous reports, our data indicate that the activity of CX3CR1 on resting monocytes is sufficient to mediate cell adhesion to CX3CL1. However, the basal, nonstimulated adhesion activity is low, and we hypothesized that like the integrins, CX3CR1 may require a preceding activation step to trigger firm leukocyte adhesion. Compatible with this hypothesis, stimulation of monocytes with MCP-1 significantly increased their adhesion to immobilized CX3CL1, under both static and physiological flow conditions. The increase of the adhesion activity was mediated through CCR2-dependent signaling and obligatory activation of the p38 MAPK pathway. Stimulation with MCP-1 also induced a rapid increase of CX3CR1 protein on the cell surface. Inhibition of the p38 MAPK pathway prevented this increase of CX3CR1 surface expression and blunted the effect of MCP-1 on cell adhesion, indicating a causal link between receptor surface density and adhesion activity. Together, our data suggest that a chemokine signal is required for firm CX3CR1-dependent adhesion and demonstrate that CCR2 is an important regulator of CX3CL1-dependent leukocyte adhesion.

Periplocoside E inhibits experimental allergic encephalomyelitis by suppressing interleukin 12-dependent CCR5 expression and interferon-gamma-dependent CXCR3 expression in T lymphocytes

Periplocoside E (PSE) was found to inhibit primary T-cell activation in our previous study. Now we examined the effect and mechanisms of PSE on the central nervous system (CNS) demyelination in experimental allergic encephalomyelitis (EAE). C57BL/6 mice immunized with myelin oligodendrocyte glyco-protein (MOG) were treated with PSE following immunization and continued throughout the study. The effect on the progression of EAE and other relevant parameters were assessed. PSE reduced the incidence and severity of EAE. Spinal cord histopathology analysis showed that the therapeutic effect of PSE was associated with reduced mononuclear cell infiltration and CNS inflammation. As reverse transcription-polymerase chain reaction analysis showed, PSE decreased the CD4(+), CD8(+), and CD11b(+) cell infiltration. T cells from lymph nodes of MOG-immunized mice expressed enhanced levels of CCR5 and CXCR3 mRNA compared with T cells from normal mice. However, CCR5 and CXCR3 expressions were suppressed in T cells from PSE-treated mice. In vitro study also showed PSE inhibited interferon (IFN)-gamma-dependent CXCR3 expression in T cells through suppressing T-cell receptor (TCR) ligation-induced IFN-gamma production, whereas it inhibited interleukin (IL)-12-dependent CCR5 expression through suppressing IL-12 reactivity in TCR-triggered T cells. As a result, the initial influx of T cells into CNS was inhibited in PSE-treated mice. The consequent activation of macrophages/microglia cells was inhibited in spinal cord from PSE-treated mice as determination of chemokine expressions (CCL2, CCL3, CCL4, CCL5, CXCL9, and CXCL10). Consistently, the secondary influx of CD4(+), CD8(+), and CD11b(+) cells was decreased in spinal cords from PSE-treated mice. These findings suggest the potential therapeutic effect of PSE on multiple sclerosis.

[Expressions of CXCL16/CXCR6 and CXCL12/CXCR4 in first-trimester human trophoblast cells]

OBJECTIVE

To investigate the transcription and protein expressions of chemokines CXCL16, CXCL12 and their receptors CXCR6, CXCR4 in first-trimester human cytotrophoblast cells and human choriocarcinoma cell line JAR.

METHODS

Transcriptions of CXCR6, CXCL16, CXCR4, CXCL12 in purified first-trimester human trophoblast cells and JAR line were assessed by semi-quantitative RT-PCR, and protein expressions of CXCR6, CXCL16, CXCR4, CXCL12 were analyzed in primary cultured villous cytotrophoblasts (VCT), extravillous cytotrophoblasts (EVCT), JAR line and placentas by immunostaining.

RESULTS

CXCR6 and CXCR4 were highly transcribed in primary cultured trophoblast cells with mRNA relative level of 1.12 +/- 0.25 and 1.08 +/- 0.11 respectively, and their ligands CXCL16 and CXCL12 were transcribed moderately with mRNA relative level of 0.89 +/- 0.11 and 0.78 +/- 0.10 respectively. It was demonstrated that CXCL16, CXCL12, CXCR6 and CXCR4 were expressed in primary cultured VCT, EVCT, JAR line and placentas by immunostaining.

CONCLUSION

The co-expression of CXCL16/CXCR6 and CXCL12/CXCR4 in trophoblast cells may play a role in the proliferation and differentiation of first-trimester trophoblast cells in a manner of autocrine.

[Expressions of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 in chronic myeloid leukemia cells]

This study was aimed to explore the expression of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 in bcr/abl fusion gene positive CML cells, and to study the effects of P210(bcr/abl) fusion protein tyrosine kinase on expression of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 mRNAs in chronic myeloid leukemia cells. The expression levels of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 mRNA were detected by semi-quantitative RT-PCR in bcr/abl negative cells, bcr/abl positive cells, and P210(bcr/abl)-Rb-C-Box positive cells. The results showed that MIP-1alpha and CCR-1 mRNAs were expressed in bcr/abl negative cells, but not in positive cells. Both MCP-1 and CCR-2 mRNA cannot be detected in both bcr/abl positive and negative cells. After inhibiting P210(bcr/abl) tyrosine kinase activity by Rb-C-Box, expressions of MIP-1alpha and CCR-1 mRNAs were restored to normal (similar to P210(bcr/abl) negative cells). It is concluded that P210(bcr/abl) fusion protein inhibits the expression of MIP-1alpha and CCR-1 in chronic myeloid leukemia cells, but does not inhibit MCP-1 and CCR-2 mRNA expressions in these leukemia cells.

Effects of dexamethazone on LPS-induced activationand migration of mouse dendritic cells revealed by a genome-wide transcriptional analysis

While lipopolysaccharides (LPS) induce dendritic cell (DC) maturation and migration to lymph nodes, glucocorticoids such as dexamethazone (Dex) have a profound suppressive effect on immune response. The mechanisms that might control this suppressive effect of Dex have been extensively investigated in lymphocytes as possible targets. Much less is known on the effects of Dex on DC, although they are recognized to regulate immunity. To get insights into possible combined effects of Dex and LPS on DC functions, we have undertaken a genome-wide analysis of differentially expressed genes of DC treated with Dex alone, LPS alone, or both, using high-density oligonucleotide microarrays. Hierarchical clustering and principal component analysis (PCA) agreed in identifying 24 h as the time point that best discriminated the three treatments. Among the counteracting effects we have observed an inhibition of Dex on the LPS-induced up-regulation of the chemokine receptor CCR7. In vivo, Dex treatment blocked the LPS-induced migration of DC, which lost their ability to reach the draining lymph nodes. In addition, we observed a synergistic effect of Dex and LPS on the expression of the secreted lipocalin 24p3, which has been reported to induce apoptosis in T cells and thus may be related to immune suppression.

Specific recruitment of CC chemokine receptor 4-positive regulatory T cells in Hodgkin lymphoma fosters immune privilege

Hodgkin lymphoma (HL) is characterized by the presence of a small number of tumor cells in a rich background of inflammatory cells, but the contribution of the abundant nontumor cells to HL pathogenesis is poorly understood. We showed that migratory CD4(+) cells induced by HL cells were hyporesponsive to T-cell receptor stimulation and suppressed the activation/proliferation of the effector CD4(+) T cells in an autologous setting. We further showed that HL cells in the affected lymph nodes were surrounded by a large number of lymphocytes expressing both CC chemokine receptor 4 (CCR4) and FOXP3. These findings indicate that the migratory cells induced by HL cells function as regulatory T (Treg) cells so that these cells create a favorable environment for the tumor cells to escape from host immune system. In addition, we showed that a chimeric anti-CCR4 monoclonal antibody (mAb) could deplete CCR4(+) T cells and inhibit the migration of CD4(+)CD25(+) T cells in vitro. Recognition of the importance of CCR4(+) Treg cells in the pathogenesis of HL will allow rational design of more effective treatments, such as use of an anti-CCR4 mAb, to overcome the suppressive effect of CCR4(+) Treg cells on the host immune response to tumor cells.

CCL27 is a critical factor for the development of atopic dermatitis in the keratin-14 IL-4 transgenic mouse model

The keratin-14 IL-4 transgenic (Tg) mouse model of atopic dermatitis (AD) is characterized by skin infiltration of T cells, early up-regulation of T(h)2 cytokines and late surge of T(h)1 cytokines. In the present study, we investigated the role of CCL27, a T cell skin-homing chemokine known to be elevated in sera of human AD patients, in disease development in our animal model of AD. The results showed that the mRNA and protein levels of CCL27 in the skin and serum were significantly increased in IL-4 Tg mice. The percentage of T cells expressing CCR10 in skin draining lymph nodes of IL-4 Tg mice was increased, consistent with the findings of >80% of skin-infiltrating T cells in Tg mice expressing CCR10. Chemotaxis transmigration assay demonstrated that CCL27 promotes a greater degree of migration of T cells in diseased Tg mice. Subcutaneous injection of neutralizing anti-CCL27 to IL-4 Tg mice with early skin lesions resulted in reduced clinical progression of inflammation, accompanied with decreased T cell and mast cell infiltration in the skin, and down-regulation of inflammatory cytokines. In conclusion, CCL27 and CCR10 interaction is important for the development of skin inflammation in our AD model.

Differential expression of chemokines and their receptors in adult and neonatal macrophages infected with human or avian influenza viruses

In 1997, avian influenza virus H5N1 was transmitted directly from chicken to human and resulted in a severe disease that had a higher mortality rate in adults than in children. The characteristic mononuclear leukocyte infiltration in the lung and the high inflammatory response in H5N1 infection prompted us to compare the chemokine responses between influenza virus–infected adult and neonatal monocyte-derived macrophages (MDMs). The effects of avian influenza virus A/Hong Kong/483/97 (H5N1) (H5N1/97), its precursor A/Quail/Hong Kong/G1/97 (H9N2) (H9N2/G1), and human influenza virus A/Hong Kong/54/98 (H1N1) (H1N1/98) were compared. Significantly higher expression of CCL2, CCL3, CCL5, and CXCL10 was induced by avian influenza viruses than by human influenza virus. Moreover, the increase in CCL3 expression in H5N1/97-infected adult MDMs was significantly higher than that in neonatal MDMs. Enhanced expression of CCR1 and CCR5 was found in avian virus–infected adult MDMs. The strong induction of chemokines and their receptors by avian influenza viruses, particularly in adult MDMs, may account for the severity of H5N1 disease

Chemokine receptor CCR6 expression level and liver metastases in colorectal cancer

PURPOSE

The liver is the primary organ of metastasis in colorectal cancer (CRC). Chemokine receptor CCR6 is expressed on a subset of T cells and is associated with their migration into the liver. This study was performed to analyze a possible association between CCR6 expressed by primary CRC and liver metastases.

PATIENTS AND METHODS

CCR6 expression levels were evaluated by immunohistology in 64 CRC primary tumor specimens. Twenty-four of 64 patients had synchronous liver metastases. Evaluation of immunostaining was performed semiquantitatively by visual assessment and quantitatively by digital image analysis (DIA). Multiple logistic regression analysis was performed to assess relevant parameters for liver metastases.

RESULTS

CCR6 expression was verified in all 64 primary tumor specimens with considerable variations in intensity; 21 tumors (33%) demonstrated weak CCR6 staining, 32 (50%) demonstrated intermediate staining, and 11 (17%) demonstrated strong staining. Quantitative assessment by DIA showed an up to 5-log difference in CCR6 values. CCR6 staining was significantly stronger in tumor cells compared with adjacent colon epithelial cells (P < .0005). Multiple logistic regression analysis, controlling for age, sex, tumor stage, nodal status, pathologic grade, and preoperative carcinoembryonic antigen levels, revealed that CCR6 staining in the primary tumor was independently associated with the presence of liver metastases (odds ratio = 2.1; P = .002).

CONCLUSION

The association between expression level of CCR6 in primary CRC and synchronous liver metastases suggests that CCR6 and its ligand may be involved in the metastatic spread to the liver. Therefore, CCR6 may be a potential target for specific therapeutic interventions.

CD24 Ala/Val polymorphism and multiple sclerosis

CD24 is expressed on a broad range of cells in the immune and central nervous systems and appears to be required for development of experimental autoimmune encephalomyelitis in mice. Association of a CD24 Ala/Val coding polymorphism with susceptibility to and progression of multiple sclerosis was recently reported. We typed this coding polymorphism in a combined cohort of 1,180 cases and 1,168 unrelated and family-based controls from Belgium and the UK, but were unable to confirm either association. Since the CD24 gene is part of a segmental duplication, special care is required for the identification and genotyping of single nucleotide polymorphisms.

Increased CXCR3 expression associated with CD3-positive lymphocytes in the liver and biliary remnant in biliary atresia

BACKGROUND

Lymphocyte-mediated inflammatory damage of the bile ducts has been proposed as a potential mechanism in the pathogenesis of biliary atresia (BA). Chemokines regulate leukocyte migration and act as critical organizers of cell distribution in inflammatory responses. The aim of this study was to analyze the infiltration of T lymphocytes and the expression of a chemokine receptor, CXCR3, predominantly expressed on type 1 polarized T cells (T(H)1, T(C)1) in the liver and excised biliary remnants in infants with BA.

METHODS

Immunohistochemistry for CD3, CD8, and CXCR3 was performed using liver biopsy specimens collected from the following 3 age-matched groups of patients: group 1, BA (nonsyndromic) at the time of Kasai portoenterostomy (n = 10); group 2, congenital choledochal dilatation (n = 2); and group 3, other cholestatic diseases including paucity of intrahepatic bile ducts and cholestasis (n = 3) related to total parenteral nutrition. Cellular staining on each section was graded from 0 to 4 and compared using nonparametric statistics.

RESULTS

Infiltrating CD3+ and CD8+ lymphocytes in the portal tracts were significantly increased in group 1 (3.1 +/- 0.4, 2.8 +/- 0.4), compared with groups 2 (1.0 +/- 0.0, 1.0 +/- 0.0) and 3 (1.7 +/- 0.3, 1.5 +/- 0.5) (P < .01, P < .05). CXCR3+ mononuclear cells were significantly increased in group 1 (2.6 +/- 0.3) compared with groups 2 (0.5 +/- 0.5) and 3 (0.7 +/- 0.3) (P < .05). They were mainly found in the portal tracts with a similar distribution to CD3+ cells. CXCR3+ cells and CD3+ cells also showed a similar distribution in specimens of biliary remnants from just below the portal plate.

CONCLUSIONS

Increased expression of CXCR3 associated with a significantly increased CD3 and CD8 T-cell infiltration suggests that CXCR3+ lymphocytes in a type 1 (T(H)1, T(C)1) cytokine milieu may play a role in the pathogenesis of BA.

Oxidative stress promotes polarization of human T cell differentiation toward a T helper 2 phenotype

These studies were conducted to determine the effects of oxidative stress on human T cell differentiation and polarization into Th1 or Th2 phenotypes. Highly purified naive CD4+ T cells were isolated from PBMC of healthy, nonatopic donors. CD4+ T cells were stimulated with anti-CD3 and anti-CD28 mAb in the presence or absence of oxidative stress as supplied by 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), which generates a low level of superoxide anion. Increases in cellular superoxide were observed by exposure to DMNQ. Exposure of unpolarized CD4+ T cells to IL-12 or IL-4 resulted in a Th1 or Th2 phenotype, respectively. T cells stimulated in the absence of polarizing cytokines secreted modest amounts of IFN-gamma and TNF-alpha. Cells stimulated in the continuous presence of 5 microM DMNQ, displayed a marked up-regulation in Th2 cytokines, including IL-4, IL-5, and IL-13, but not the Th1 cytokine IFN-gamma. Th2 responses were blunted by concomitant exposure to thiol antioxidants. Long-term exposure of T cells to DMNQ resulted in growth of cells expressing CCR4, and a decrease in cells expressing CXCR3, indicating phenotypic conversion to Th2 cells. These results suggest that oxidative stress favors a Th2-polarizing condition.

Chemokine receptors in head and neck cancer: association with metastatic spread and regulation during chemotherapy

Head and neck carcinomas are histologically and clinically heterogeneous. While squamous cell carcinomas (SCC) are characterized by lymphogenous spread, adenoid cystic carcinomas (ACC) disseminate preferentially hematogenously. To study cellular and molecular mechanisms of organ-specific metastasis, we used SCC and ACC cell lines and tumor tissues, obtained from patients with primary or metastatic disease. Comprehensive analysis at the mRNA and protein level of human chemokine receptors showed that SCC and ACC cells exhibited distinct and nonrandom expression profiles for these receptors. SCC predominantly expressed receptors for chemokines homeostatically expressed in lymph nodes, including CC chemokine receptor (CCR) 7 and CXC chemokine receptor (CXCR)5. No difference in expression of chemokine receptors was seen in primary SCC and corresponding lymph node metastases. In contrast to SCC, ACC cells primarily expressed CXCR4. In chemotaxis assays, ACC cells were responsive to CXCL12, the ligand for CXCR4. Exposure of ACC cells to cisplatin resulted in upregulation of CXCR4 on the cell surface, which was repressed by the transcriptional inhibitor, alpha-amanitin. Treatment of ACC cells with CXCL12 resulted in the activation of Akt and ERK1/2 pathways. Furthermore, CXCL12 suppressed the rate of apoptosis induced by cisplatin in ACC cells, suggesting that signaling via CXCR4 may be part of a tumor cell survival program. Discrimination of the chemokine receptor profile in SCC and ACC in vitro and in tissues provided insights into their distinct biologic and clinical characteristics as well as indications that chemokine receptors might serve as future therapeutic targets in these malignancies.

Immunological studies of mitoxantrone in primary progressive MS

Mitoxantrone (MX) has demonstrated efficacy in multiple sclerosis (MS), but its immunologic mechanisms of action are poorly understood. Furthermore, no study has examined the immunological effects of MX in primary progressive MS (PPMS). This study investigated the immunological effects of MX therapy in PPMS patients. Lymphocyte phenotypes and chemokine receptor (CCR) expression were evaluated by flow cytometry on fresh PBMC from 20 PPMS patients enrolled in a placebo (PLC)-controlled trial of MX. Longitudinal data were collected at weeks 0, 12, 24, 36 and short-term data (pre-/post-infusion) were collected at weeks 0 and 36. CXCR3, CCR1, CCR2 and CCR5 on CD4 and CD8 T cells and CD14 monocytes were evaluated. MX therapy induced a significant increase in the proportion of CD8 T cells (CD45RO(-)) over 9 months. Expression of several CCR increased following MX treatment. Two of the eight MX-treated patients demonstrated dramatic upregulation (70-76%) of CCR2 on monocytes. These two patients were the only MX-treated patients to demonstrate active inflammation by magnetic resonance imaging (MRI). PLC patients did not show significant changes in CCR expression. MX therapy was not associated with selective loss of CD4, CD8 or CD14 cells 1 month after treatment or over 9 months. These results suggest that MX therapy leads to a longitudinal increase in CD8 T cells and may increase CCR in patients with inflammation on MRI. Overall, MX did not show extensive immune changes in PPMS, although patients with active disease (gadolinium enhancing lesions) may identify a subset of PPMS subjects who respond immunologically to MX therapy. An improved understanding of MX may help identify markers of disease activity and response to therapy.

Differential regulation of CC chemokine receptors by 9-cis retinoic acid in the human mast cell line, HMC-1

Mast cells are well known as effector cells in a variety of inflammatory diseases, including asthma as well as other allergic disorders. The precise role of 9-cis retinoic acid (9CRA) in mast cells is not understood despite the accepted fact that 9CRA regulates inflammatory responses and neutrophil differentiation. In this study, we investigated the effects of 9CRA on the expression of CC chemokine receptors in the human mast cell line, HMC-1. 9CRA selectively inhibits the CCR2 mRNA level and increases the CCR3 mRNA level in both a time and dose dependent manner. Other CC chemokine receptors, including CCR1, CCR4 and CCR5 are not altered by treatment with 9CRA. Both TNF-alpha and LPS, known pro-inflammatory molecules, have no effect on mRNA levels of CC chemokine receptors. For surface expression, 9CRA decreased the CCR2 level but had no effect on the CCR3 level. 9CRA inhibited the chemotactic activity in response to the CCR2-dependent chemokine, MCP-1/CCL2 but not in response to CCR3-specific chemokine, eotaxin/CCL11. 9CRA decreased spontaneous homotype clustering. Therefore, our results demonstrate that 9CRA differentially decreases both CCR2 expression and chemotactic ability of HMC-1 cells, and may regulate the inflammatory effects of mast cells.

Essential contribution of a chemokine, CCL3, and its receptor, CCR1, to hepatocellular carcinoma progression

We previously observed that a chemokine, macrophage inflammatory protein-1 alpha/CCL3, and its receptor, CCR1, were aberrantly expressed in human hepatocellular carcinoma (HCC) tissues. Here, we show that CCL3 and CCR1 are also expressed in 2 different models of this cancer; N-nitrosodiethylamine (DEN)-induced HCC and HCC induced by hepatitis B virus surface (HBs) antigen-primed splenocyte transfer to myelo-ablated syngeneic HBs antigen transgenic mice. At 10 months after DEN treatment, foci number and sizes were remarkably reduced in CCR1- and CCL3-deficient mice, compared with those of wild-type (WT) mice, although tumor incidence were marginally, but significantly, higher in CCR1- and CCL3-deficient mice than in WT mice. Of note is that tumor angiogenesis was also markedly diminished in CCL3- and CCR1-deficient mice, with a concomitant reduction in the number of intratumoral Kupffer cells, a rich source of growth factors and matrix metalloproteinases (MMPs). Among growth factors and MMPs that we examined, only MMP9 and MMP13 gene expression was augmented progressively in liver of WT mice after DEN treatment. Moreover, MMP9, but not MMP13, gene expression was attenuated in CCR1- and CCL3-deficient mice, compared with that of WT mice. Furthermore, MMP9 was expressed mainly by mononuclear cells but not hepatoma cells, and MMP9-expressing cell numbers were decreased in CCR1- or CCL3-deficient mice, compared with WT mice. These observations suggest the contribution of the CCR1-CCL3 axis to HCC progression.

Molecular basis of age-associated cytokine dysregulation in LPS-stimulated macrophages

Aged humans and rodents are susceptible to infection with Streptococcus pneumoniae bacteria as a result of an inability to make antibodies to capsular polysaccharides. This is partly a result of decreased production of proinflammatory cytokines and increased production of interleukin (IL)-10 by macrophages (Mphi) from aged mice. To understand the molecular basis of cytokine dysregulation in aged mouse Mphi, a microarray analysis was performed on RNA from resting and lipopolysaccharide (LPS)-stimulated Mphi from aged and control mice using the Affymetrix Mouse Genome 430 2.0 gene chip. Two-way ANOVA analysis demonstrated that at an overall P < 0.01 level, 853 genes were regulated by LPS (169 in only the young, 184 in only the aged, and 500 in both). Expression analysis of systematic explorer revealed that immune response (proinflammatory chemokines, cytokines, and their receptors) and signal transduction genes were specifically reduced in aged mouse Mphi. Accordingly, expression of Il1 and Il6 was reduced, and Il10 was increased, confirming our previous results. There was also decreased expression of interferon-gamma. Genes in the Toll-like receptor-signaling pathway leading to nuclear factor-kappaB activation were also down-regulated but IL-1 receptor-associated kinase 3, a negative regulator of this pathway, was increased in aged mice. An increase in expression of the gene for p38 mitogen-activated protein kinase (MAPK) was observed with a corresponding increase in protein expression and enzyme activity confirmed by Western blotting. Low doses of a p38 MAPK inhibitor (SB203580) enhanced proinflammatory cytokine production by Mphi and reduced IL-10 levels, indicating that increased p38 MAPK activity has a role in cytokine dysregulation in the aged mouse Mphi.

Aberrant expression of CC and CXC chemokines and their receptors in patients with asthma

This study further elucidates the roles of selected chemokines (IP-10, MIG, and RANTES) and their receptors (CCR3, CCR5, and CXCR3) in asthma. We compared their profiles in six groups of participants-atopic cohort and nonatopic cohort (each including controls and asthmatic patients with or without steroid therapy). Plasma concentration of IP-10 was significantly lower while that of RANTES and the expression of CCR3 were higher in asthmatic patients (all p < 0.05). Plasma RANTES correlated positively with the GINA severity score in all asthmatic patients (r=0.27, p < 0.05), and with IL-13 in nonatopic asthmatic patients (r=0.46, p < 0.05). In asthmatic patients, the ex vivo release of IP-10 and MIG was attenuated in PBMC activated with allergen, mitogens and IL-18 (p < 0.05). In conclusion, plasma RANTES may be a surrogate marker for asthma and the diminished Th1 related CXC chemokine production may contribute to Th2 predominance in asthma.

Chemokine C receptor 7 expression and protection of circulating CD8+ T lymphocytes from apoptosis

Chemokine C receptor 7 (CCR7) expression is important for lymphocyte homing to tissues. We hypothesized that CCR7 also plays a role in CD8(+) T-cell protection from apoptosis. Its expression was determined on circulating T cells in patients with cancer and related to that of molecules responsible for lymphocyte susceptibility/resistance to apoptosis. Peripheral blood mononuclear cells were obtained from 36 patients with squamous cell carcinoma of the head and neck and 16 normal controls. Multicolor flow cytometry was used to evaluate CCR7, Fas, Bax, and Bcl-2 expression in CD8(+) T cells. Annexin V binding to CD8(+)CCR7(+) and CD8(+)CCR7(-) T-cell subsets was compared. Fewer CD8(+)CCR7(+) T cells bound Annexin V than CD8(+)CCR7(-) T cells in normal control and patients (P < 0.0001). CCR7 expression correlated with higher Bcl-2 but lower Bax and Fas expression levels in CD8(+) T cells in both normal control and patients (P < 0.0001). In patients, the CD8(+)CCR7(+) subset was reduced relative to normal control (P = 0.008) and replaced with an excess of apoptosis-sensitive CD8(+)CCR7(-) T cells. To study CCR7 signaling, CD8(+) T cells were stimulated with CCR7 ligands, chemokine C ligands 19 or 21. Ligand binding to CCR7 resulted in phosphorylation of Akt and increased Bcl-2 expression in CD8(+)CCR7(+) T cells, suggesting that CCR7 protects effector T cells from apoptosis through the phosphatidylinositol 3-kinase/Akt pathway. The absence of CCR7 expression on the majority of CD8(+) T cells in the peripheral circulation of patients with squamous cell carcinoma of the head and neck contributes to apoptosis and a rapid turnover of these effector cells.

Monocyte chemoattractant protein-1 induces a novel transcription factor that causes cardiac myocyte apoptosis and ventricular dysfunction

Monocyte chemoattractant protein-1 (MCP-1; CCL2)-mediated inflammation plays a critical role in the development of ischemic heart disease (IHD). However, the gene expression changes caused by signal transduction, triggered by MCP-1 binding to its receptor CCR2, and their possible role in the development of IHD are not understood. We present evidence that MCP-1 binding to CCR2 induces a novel transcription factor (MCP-induced protein [MCPIP]) that causes cell death. Gene microarray analysis showed that when expressed in hiuman embryonic kidney 293 cells, MCPIP induced apoptotic gene families before causing cell death. Mutagenesis studies showed that the structural features required for transcription factor-like activity were also required for causing cell death. Activation of caspase-3 was detected after MCPIP transfection and Z-VAD-fmk partially inhibited cell death. Cardiomyocyte-targeted expression of MCP-1 in mice caused death by heart failure at 6 months of age. MCPIP expression increased in parallel with the development of ventricular dysfunction. In situ hybridization showed the presence of MCPIP transcripts in the cardiomyocytes and immunohistochemistry showed that MCPIP was associated with the cardiomyocyte nuclei of apoptotic cardiomyocytes. CCR2 expression in cardiomyocytes increased with the development of IHD. MCPIP production induced by MCP-1 binding to CCR2 in the cardiomyocytes is probably involved in the development of IHD in this murine model. MCPIP transcript levels were much higher in the explanted human hearts with IHD than with nonischemic heart disease. These results provide a molecular insight into how chronic inflammation and exposure to MCP-1 contributes to heart failure and suggest that MCPIP could be a potential target for therapeutic intervention.

α-melanocyte-stimulating hormone down-regulates CXC receptors through activation of neutrophil elastase

Considering the role of interleukin-8 (IL-8) in a large number of acute and chronic inflammatory diseases, the regulation of IL-8-mediated biological responses is important. Alpha-melanocyte-stimulating hormone (alpha-MSH), a tridecapeptide, inhibits most forms of inflammation by an unknown mechanism. In the present study, we have found that alpha-MSH interacts predominantly with melanocortin-1 receptors and inhibits several IL-8-induced biological responses in macrophages and neutrophils. It down-regulated receptors for IL-8 but not for TNF, IL-4, IL-13 or TNF-related apoptosis-inducing ligand (TRAIL) in neutrophils. It down-regulated CXCR type 1 and 2 but not mRNA levels. alpha-MSH did not inhibit IL-8 binding in purified cell membrane or affinity-purified CXCR. IL-8 or anti-CXCR Ab protected against alpha-MSH-mediated inhibition of IL-8 binding. The level of neutrophil elastase, a specific serine protease, but not cathepsin G or proteinase 3 increased in alpha-MSH-treated cells, and restoration of CXCR by specific neutrophil elastase or serine protease inhibitors indicates the involvement of elastase in alpha-MSH-induced down-regulation of CXCR. These studies suggest that alpha-MSH inhibits IL-8-mediated biological responses by down-regulating CXCR through induction of serine protease and that alpha-MSH acts as a potent immunomodulator in neutrophil-driven inflammatory distress.

Corticosterone regulates expression of CCL2 in the intact and chemically injured hippocampus

Expression of the chemokine (C-C motif) ligand 2 (CCL2), also known as, monocyte chemoattractant protein (MCP)-1, increases in response to disease-, trauma-, or toxicant-induced damage to the central nervous system (CNS). In the periphery, endogenous and exogenous glucocorticoids are known to suppress CCL2 expression associated with inflammatory conditions. However, such actions of glucocorticoids on CCL2 expression in the CNS remain unknown. Here, we explored the effects of the glucocorticoid, corticosterone (CORT), on the expression of CCL2 and its receptors, CCR2 and CCR5, in the hippocampal formation using intact, adrenalectomized (ADX) and trimethyltin (TMT)-treated rats. An immunosuppressive regimen of CORT did not alter the mRNA expression of CCL2 or its receptors in the hippocampus. ADX, however, markedly increased the expression of CCL2 and CCR2 mRNAs in the hippocampus, while CORT replacement reversed the effects of ADX on CCL2 gene expression. Hippocampal damage resulting from systemic administration of the organometallic neurotoxicant, TMT, was associated with microglial activation, as evidenced by enhanced expression of microglial markers integrin alphaM (CD11b) and F4/80, as well as, microglia-associated factors, CCL2 and IL-1alpha. An immunosuppressive dose of CORT, suppressed TMT-induced expression of CCL2. Given the association of CCL2 with microglial activation, it appears that CORT may play a role in regulating microglial activation. However, CORT treatment did not alter TMT-mediated neuronal damage and astrogliosis. Such observations suggest that injury-related expression of microglia-associated chemokines and cytokines may subserve a role unrelated to neuronal damage. In summary, our data indicate that in the CNS, CCL2 gene expression is under negative regulation by glucocorticoids.

Increased Expression of RANTES, CCR3 and CCR5 in the Lesional Skin of Patients with Atopic Eczema

BACKGROUND

Atopic eczema (AE) is a relapsing inflammatory disease based on IgE sensitization and characterized by peripheral blood eosinophilia and eosinophil infiltration into the lesional skin. In the patch test reaction of AE by allergens, an increased infiltration of activated eosinophils has been demonstrated peaking at 24-48 h. Regulated on activation normal T cell expressed and secreted (RANTES/CCL5) is a chemokine that induces eosinophil migration, and CCR3 and CCR5 are the receptors of RANTES.

OBJECTIVE

In order to further clarify the pathomechanisms of eosinophil infiltration in ongoing chronic inflammation in the skin of patients with AE and its relation to disease severity, we examined the expression of RANTES and its receptors CCR3 and CCR5 in challenged and unchallenged lesional skin of AE.

METHODS

We examined the number of RANTES+ cells, CCR3+ cells, CCR5+cells, activated (EG2+) eosinophils and CD3+ T cells in normal skin of healthy volunteers, and in challenged lesional skin (24 h after mite patch test) as well as unchallenged lesional skin of AE patients by immunohistochemistry. The cellular source of RANTES, CCR3 and CCR5 was analyzed by double immunohistochemistry using specific antibodies to RANTES, CCR3 or CCR5, and antibodies to ECP (EG2) or CD3.

RESULTS

The numbers of RANTES+ cells, CCR3+ cells, CCR5+ cells, EG2+ cells and CD3+ cells were all significantly increased in challenged (mite patch-tested) lesional skin of AE patients as compared to those in unchallenged lesional skin and normal skin. The numbers of these cells in unchallenged lesional skin were greater than those in normal skin. The number of EG2+ cells in the unchallenged lesional skin correlated with both the peripheral blood eosinophil count and the SCORAD index. The number of EG2+ cells in challenged lesional skin correlated with the number of CCR5+ cells. Activated eosinophils and T cells expressed RANTES and various proportions of these cells were CCR3+ and CCR5+ in both challenged and unchallenged lesional skin.

CONCLUSION

Taken together, these results suggest that RANTES as well as its receptors CCR3 and CCR5 may play important roles in the orchestration of eosinophil infiltration in ongoing chronic inflammation in AE, and also reflect the severity of disease.

STAT4/6-dependent differential regulation of chemokine receptors

The major cell fate decision of the CD4+ helper T cells is the development of Th1 and Th2 phenotype, the balance of which determines the outcome of a wide variety of autoimmune responses. Signal transducers and activators of transcription (STATs), in particular STAT4 and STAT6, are essential for the development of Th1 and Th2 cells, respectively. We used Balb/c mice lacking STAT4 or STAT6 to explore the ability of helper T cells to express chemokine receptors. We demonstrated that both STAT4-/- and STAT6-/- CD4+ lymphocytes showed impaired expansion as well as differentiation into IFN-gamma-secreting Th1 cells and IL2-, IL4-, IL10-secreting Th2 cells. Interestingly, the expression of chemokine receptors, which is STAT4/6-dependent, was differentially regulated via two distinct mechanisms, positively (CCR3, CCR4) and negatively (CCR5, CCR7). These results provide the basis for STAT-dependent differential regulation of chemokine receptors in Th subsets.

The immune paradox of sarcoidosis and regulatory T cells

Sarcoidosis is characterized by extensive local inflammation (granuloma, cytokine secretion) associated with anergy (poor response to antigens in vitro and in vivo). We postulated that this paradoxical situation would correspond to a disequilibrium between effector and regulatory T lymphocytes (T reg cells). We show that CD4⁺CD25^brightFoxP3⁺ cells accumulate at the periphery of sarcoid granulomas, in bronchoalveolar lavage fluid, and in peripheral blood of patients with active disease. These cells exhibited powerful antiproliferative activity, yet did not completely inhibit TNF-α production. Sarcoidosis is therefore associated with a global T reg cell subset amplification whose activity would be insufficient to control local inflammation. At the same time, peripheral T reg cells exert powerful antiproliferative activity that may account for the state of anergy. Altogether, these findings advance our conceptual understanding of immune regulation in a way that resolves the immune paradox of sarcoidosis and permit us to envisage a profound clinical impact of T reg cell manipulation on immunity.

Respiratory Syncytial Virus G Protein and G Protein CX3C Motif Adversely Affect CX3CR1+T Cell Responses

Interactions between fractalkine (CX3CL1) and its receptor, CX3CR1, mediate leukocyte adhesion, activation, and trafficking. The respiratory syncytial virus (RSV) G protein has a CX3C chemokine motif that can bind CX3CR1 and modify CXCL1-mediated responses. In this study, we show that expression of the RSV G protein or the G protein CX3C motif during infection is associated with reduced CX3CR1+ T cell trafficking to the lung, reduced frequencies of RSV-specific, MHC class I-restricted IFN-gamma-expressing cells, and lower numbers of IL-4- and CX3CL1-expressing cells. In addition, we show that CX3CR1+ cells constitute a major component of the cytotoxic response to RSV infection. These results suggest that G protein and the G protein CX3C motif reduce the antiviral T cell response to RSV infection.

CXCR4 expression is associated with lymph-node metastasis of oral squamous cell carcinoma

The support mechanisms that are involved in lymph-node metastasis of oral squamous cell carcinoma (OSCC) remain largely unknown. Recent studies have demonstrated that tumor cells express chemokine receptors and use chemokines to metastasize to the target organ in many malignancies in humans. In this study, we examined the expression and function of chemokines and their receptors in OSCC. The expression of chemokine receptors was assessed in eight OSCC cell lines. CXCR3 mRNA and protein were expressed in all the OSCC cell lines examined, while CXCR4 mRNA and protein were expressed only in HSC2, HSC3, and Ca9-22 cells. Treatment with the ligand for CXCR4, stromal cell-derived factor-1 (SDF-1), enhanced the motility and invasiveness of OSCC cells expressing CXCR4. However, the CXCR3 ligand, Mig, did not affect the migration or invasiveness of CXCR3-positive cells. We also evaluated the clinical significance of CXCR4 expression immunohistochemically. CXCR4 expression was detected in 27 (30%) of the 90 OSCC tissues tested, and was localized in the membrane and cytoplasm of cancer cells. There was a highly significant correlation between CXCR4 expression and lymph-node metastasis (P=0.0035). Collectively, these findings suggest that CXCR4 might be involved in the lymph-node metastasis of OSCC.

Targeting Herpesvirus Reliance of the Chemokine System

Viral infections depend on an intimate relationship between the infectious agent and the host cells. Viruses need the host cells for replication, while the innate- and adaptive- immunesystem of the host is fighting to kill the infected cell in order to clear out the pathogen and survive the infection. However, since both virus and host exist, the organisms struggle must reach an ecological equilibrium. Among the best-studied interactions between viruses and the host immune system are those between herpesviruses and their hosts. Herpesviruses are known to devote a significant part of their large genomes on immuno-modulatory genes, some encoding chemokines or chemokine receptors. These genes, which may be dispensable for viral replication in vitro, are highly important for viral growth in vivo, for viral dissemination and disease progression. Indeed, all beta and gamma-herpesviruses have acquired homologs of both chemokines and chemokine receptors belonging to the 7 transmembrane (7TM) spanning, G protein-coupled receptor family. 7TM receptors are very efficient drug targets and are currently the most popular class of investigational drug targets. A notable trait for the virus encoded chemokine receptors seems to be their constitutive activity. The biological function of the constitutive activity is still unclear, but it has become clear that the receptors are involved in important parts of the viral lifecycle in vivo, and that the receptor signaling is involved in gamma-herpesvirus mediated cell transformation. Therefore, blocking the signaling of these receptors will provide an efficient and highly specific way to inhibit viral replication in vivo and disease progression in the hosts.

gammadelta T cells increase with gastric mucosal interleukin (IL)-7, IL-1beta, and Helicobacter pylori urease specific immunoglobulin levels via CCR2 upregulation in Helicobacter pylori gastritis

BACKGROUND AND AIMS

The purpose of this study was to investigate possible factors that could impact on gammadelta T cell accumulation in the gastric mucosa.

METHOD

Subjects were 22 Helicobacter pylori (H. pylori)-free and 75 H. pylori-infected mucosa biopsies classified into grades I approximately III gastritis as per our previous study. The number of gammadelta- and 45 RO-positive T cells were determined by immunostaining. Gastric mucosal anti-H. pylori urease specific antibodies and interleukin (IL)-1beta, IL-2, 4, 7, 10 and IL-12 levels were assayed by enzyme-linked immunosorbent assay (ELISA). CC chemokine receptor 2 (CCR2) expression levels, migration, and cytokine production in gammadelta T cells stimulated by H. pylori urease were also evaluated.

RESULTS

The gammadelta T cell count was significantly higher in grade III gastritis which exhibits strong immunoglobulin (Ig)A and IgG responses to H. pylori urease with lymphoid follicles than in other groups. gammadelta T cell count was significantly correlated with IL-1beta and interleukin-7 (IL-7) levels in the gastric mucosa. H. pylori urease immunoreactivity was detected in lamina propria of grade III gastritis, along with many gammadelta T cells. After H. pylori eradication therapy, the gammadelta T cell count in grade III gastritis significantly decreased. H. pylori urease stimulated significant increases in CCR2 expression levels, although to a lesser degree than those induced by IL-7 stimulation in both peripheral and mucosal gammadelta T cells. Interferon (IFN)-gamma and IL-10 production was also stimulated by H. pylori urease in peripheral gammadelta T cells.

CONCLUSIONS

Gastric mucosal increases in IL-7 and IL-1beta closely corresponded to the accumulation of gammadelta T cells in gastric mucosa. An association was also seen between gammadelta T cell accumulation and H. pylori urease-specific Ig levels.

Plasmodium yoelii 17XL infection up-regulates RANTES, CCR1, CCR3 and CCR5 expression, and induces ultrastructural changes in the cerebellum

BACKGROUND

Malaria afflicts 300-500 million people causing over 1 million deaths globally per year. The immunopathogenesis of malaria is mediated partly by co mplex cellular and immunomodulator interactions involving co-regulators such as cytokines and adhesion molecules. However, the role of chemokines and their receptors in malaria immunopathology remains unclear. RANTES (Regulated on Activation Normal T-Cell Expressed and Secreted) is a chemokine involved in the generation of inflammatory infiltrates. Recent studies indicate that the degradation of cell-cell junctions, blood-brain barrier dysfunction, recruitment of leukocytes and Plasmodium-infected erythrocytes into and occlusion of microvessels relevant to malaria pathogenesis are associated with RANTES expression. Additionally, activated lymphocytes, platelets and endothelial cells release large quantities of RANTES, thus suggesting a unique role for RANTES in the generation and maintenance of the malaria-induced inflammatory response. The hypothesis of this study is that RANTES and its corresponding receptors (CCR1, CCR3 and CCR5) modulate malaria immunopathogenesis. A murine malaria model was utilized to evaluate the role of this chemokine and its receptors in malaria.

METHODS

The alterations in immunomodulator gene expression in brains of Plasmodium yoelii 17XL-infected mice was analysed using cDNA microarray screening, followed by a temporal comparison of mRNA and protein expression of RANTES and its corresponding receptors by qRT-PCR and Western blot analysis, respectively. Plasma RANTES levels was determined by ELISA and ultrastructural studies of brain sections from infected and uninfected mice was conducted.

RESULTS

RANTES (p < 0.002), CCR1 (p < 0.036), CCR3 (p < 0.033), and CCR5 (p < 0.026) mRNA were significantly upregulated at peak parasitaemia and remained high thereafter in the experimental mouse model. RANTES protein in the brain of infected mice was upregulated (p < 0.034) compared with controls. RANTES plasma levels were significantly upregulated; two to three fold in infected mice compared with controls (p < 0.026). Some distal microvascular endothelium in infected cerebellum appeared degraded, but remained intact in controls.

CONCLUSION

The upregulation of RANTES, CCR1, CCR3, and CCR5 mRNA, and RANTES protein mediate inflammation and cellular degradation in the cerebellum during P. yoelii 17XL malaria.

V alpha 24-invariant NKT cells from patients with allergic asthma express CCR9 at high frequency and induce Th2 bias of CD3+ T cells upon CD226 engagement

We have demonstrated that Valpha24(+)Vbeta11(+) invariant (Valpha24(+)i) NKT cells from patients with allergic asthma express CCR9 at high frequency. CCR9 ligand CCL25 induces chemotaxis of asthmatic Valpha24(+)i NKT cells but not the normal cells. A large number of CCR9-positive Valpha24(+)i NKT cells are found in asthmatic bronchi mucosa, where high levels of Th2 cytokines are detected. Asthmatic Valpha24(+)i NKT cells, themselves Th1 biased, induce CD3(+) T cells into an expression of Th2 cytokines (IL-4 and IL-13) in cell-cell contact manner in vitro. CD226 are overexpressed on asthmatic Valpha24(+)i NKT cells. CCL25/CCR9 ligation causes directly phosphorylation of CD226, indicating that CCL25/CCR9 signals can cross-talk with CD226 signals to activate Valpha24(+)i NKT cells. Prestimulation with immobilized CD226 mAb does not change ability of asthmatic Valpha24(+)i NKT cells to induce Th2-cytokine production, whereas soluble CD226 mAb or short hairpin RNA of CD226 inhibits Valpha24(+)i NKT cells to induce Th2-cytokine production by CD3(+) T cells, indicating that CD226 engagement is necessary for Valpha24(+)i NKT cells to induce Th2 bias of CD3(+) T cells. Our results are providing with direct evidence that aberration of CCR9 expression on asthmatic Valpha24(+)i NKT cells. CCL25 is first time shown promoting the recruitment of CCR9-expressing Valpha24(+)i NKT cells into the lung to promote other T cells to produce Th2 cytokines to establish and develop allergic asthma. Our findings provide evidence that abnormal asthmatic Valpha24(+)i NKT cells induce systemically and locally a Th2 bias in T cells that is at least partially critical for the pathogenesis of allergic asthma.

CCR3 expression and function in asthmatic airway smooth muscle cells

Asthma is characterized by an increase in airway smooth muscle mass and a decreased distance between the smooth muscle layer and the epithelium. Furthermore, there is evidence to indicate that airway smooth muscle cells (ASMC) express a wide variety of receptors involved in the immune response. The aims of this study were to examine the expression of CCR3 on ASMC, to compare this expression between asthmatic and nonasthmatic subjects, and to determine the implications of CCR3 expression in the migration of ASMC. We first demonstrated that ASMC constitutively express CCR3 at both mRNA and protein levels. Interestingly, TNF-alpha increases ASMC surface expression of CCR3 from 33 to 74%. Furthermore, using FACS analysis, we found that ASMC CCR3 is expressed to a greater degree in asthmatic vs control subjects (95 vs 75%). Functionality of the receptor was demonstrated by calcium assay; the addition of CCR3 ligand eotaxin to ASMC resulted in an increase in intracellular calcium production. Interestingly, ASMC was seen to demonstrate a positive chemotactic response to eotaxin. Indeed, ASMC significantly migrated toward 100 ng/ml eotaxin (2.2-fold increase, compared with control). In conclusion, the expression of CCR3 by ASMC is increased in asthmatics, and our data show that a CCR3 ligand such as eotaxin induces migration of ASMC in vitro. These results may suggest that eotaxin could be involved in the increased smooth muscle mass observed in asthmatics through the activation of CCR3.

The role of ICOS in the CXCR5+ follicular B helper T cell maintenance in vivo

ICOS is a new member of the CD28 family of costimulatory molecules that is expressed on activated T cells. Its ligand B7RP-1 is constitutively expressed on B cells. Although the blockade of ICOS/B7RP-1 interaction inhibits T cell-dependent Ab production and germinal center formation, the mechanism remains unclear. We examined the contribution of ICOS/B7RP-1 to the generation of CXCR5+ follicular B helper T (T(FH)) cells in vivo, which preferentially migrate to the B cell zone where they provide cognate help to B cells. In the spleen, anti-B7RP-1 mAb-treated or ICOS-deficient mice showed substantially impaired development of CXCR5+ T(FH) cells and peanut agglutinin+ germinal center B cells in response to primary or secondary immunization with SRBC. Expression of CXCR5 on CD4+ T cells was associated with ICOS expression. Adoptive transfer experiments showed that the development of CXCR5+ T(FH) cells was enhanced by interaction with B cells, which was abrogated by anti-B7RP-1 mAb treatment. The development of CXCR5+ T(FH) cells in the lymph nodes was also inhibited by the anti-B7RP-1 mAb treatment. These results indicated that the ICOS/B7RP-1 interaction plays an essential role in the development of CXCR5+ T(FH) cells in vivo.

T Cell-Regulated Neutrophilic Inflammation in Autoinflammatory Diseases

Previous studies of acute generalized exanthematous pustulosis, a peculiar drug hypersensitivity reaction, suggested that CXCL8-producing T cells regulate sterile, polymorphonuclear neutrophil-rich skin inflammations. In this study, we test the hypothesis of whether CXCL8-producing T cells are present in autoinflammatory diseases like pustular psoriasis and Behçet's disease. Immunohistochemistry of normal skin revealed few CD4+ and CD8+ T cells, few CXCL8+ cells, and no neutrophilic infiltration, whereas in acute exacerbations of atopic dermatitis, numerous CD4+ T cells but few CD8+ T cells, neutrophils, or CXCL8+ cells were detected. In contrast, a pronounced infiltration of neutrophils and of predominantly CD4+ T cells was observed in skin biopsies from pustular psoriasis, Behçet's disease, and acute generalized exanthematous pustulosis, with infiltrating T cells strongly positive for CXCL8 and the chemokine receptor CCR6. Skin-derived T cell clones from pustular skin reactions were positive for CCR6 but negative for CCR8 and secreted high amounts of CXCL8 and GM-CSF, often together with IFN-gamma and TNF-alpha after in vitro stimulation. Moreover, some skin-derived T cell clones from Behçet's disease and from pustular psoriasis predominantly produced CXCL8 and GM-CSF, but failed to secrete IL-5 and IFN-gamma. These cells might represent a particular subset as they differ from both Th1 as well as Th2 T cells and are associated with a unique, neutrophil-rich sterile inflammation. Our findings suggest that CXCL8/GM-CSF-producing T cells may orchestrate neutrophil-rich pathologies of chronic autoinflammatory diseases like pustular psoriasis and Behçet's disease.

Augmented expression of secondary lymphoid tissue chemokine and EBI1 ligand chemokine in Crohn's disease

BACKGROUND

A dominant T helper type 1 (Th1) immune response is thought to be involved in Crohn's disease (CD). SLC/CCL21 and ELC/CCL19, chemokines that regulate T cell homing and promote recirculating T and dendritic cell (DC) interactions, help control antigen specific T cell responses.

AIMS

To investigate the Th1 response and SLC and ELC in CD pathogenesis.

METHODS

Surgically resected intestine and mesenteric lymph nodes (MLNs) from controls and patients with CD and ulcerative colitis (UC) were investigated. CD3, CD83, HECA452, VEGFR3, SLC, ELC, and CCR7 expression was studied immunohistochemically. CCR7 mRNA was quantified using real time RT-PCR.

RESULTS

ELC was almost undetectable in intestinal samples. SLC was found sporadically in lymphoid follicles, lymphoid aggregate venules, and lymphatic vessels. In MLNs, SLC was highly expressed in high endothelial venules (HEVs), lymphatic vessels, and stromal DCs, predominantly in T cell areas. ELC was highly expressed in mature DCs. There were significantly more SLC positive HEVs and ELC positive mature DCs, important components of T cell areas, in CD. SLC, ELC, and CCR7 mRNA was significantly higher in CD MLNs compared with UC. CD MLNs had increased expression of SLC and ELC, mainly in HEVs, mature DCs, and lymphatic vessels, inducing T cell hyperplasia. CCR7 mRNA was increased in T cell areas.

CONCLUSION

The dominant Th1 immune response is facilitated by interaction of SLC positive HEVs/lymphatic vessels, ELC positive mature DCs, and CCR7 positive T cells in hyperplastic T cell areas. In CD, memory T cells and mature DCs may home to MLN.

IL-4-expressing bronchoalveolar T cells from asthmatic and healthy subjects preferentially express CCR 3 and CCR 4

BACKGROUND

The concept of the polarization of chemokine receptor expression by T(H)1 and T(H)2 cells provides an attractive mechanism for their differential recruitment to tissue, which could be subject to disease-specific therapeutic intervention. The paradigm that T(H)1 cells preferentially express CXCR 3 and CCR 5 and T(H)2 cells preferentially express CCR 3, CCR 4, and CCR 8 has been well established in the setting of in vitro polarized cell lines; however, the situation in vivo appears less clear-cut.

OBJECTIVE

We sought to investigate whether this pattern of polarization can be demonstrated in human lung tissue.

METHODS

We used single-cell analysis to investigate the relationship between chemokine receptor expression and cytokine production on peripheral blood and bronchoalveolar lavage fluid T cells in patients with asthma, a putative T(H)2 disease, as well as in healthy control subjects.

RESULTS

We have found in both asthmatic and control subjects that IL-4-expressing blood and bronchoalveolar lavage fluid T cells are significantly more likely to express the T(H)2 type 2 chemokine receptors CCR 3 and CCR 4, with 10-fold and 2-fold differences in expression, respectively, compared with IFN-gamma-expressing cells.

CONCLUSION

We have provided evidence that polarization of T(H)2-type chemokine receptors on IL-4-expressing cells can be demonstrated in an in vivo setting and therefore that these cells might indeed be susceptible to differential patterns of recruitment as a result of expression of the relevant chemokines at inflammatory sites.

Liver-directed gamma interferon gene delivery in chronic hepatitis C

Gamma interferon (IFN-gamma) has been shown to inhibit replication of subgenomic and genomic hepatitis C virus (HCV) RNAs in vitro and to noncytolytically suppress hepatitis B virus (HBV) replication in vivo. IFN-gamma is also known for its immunomodulatory effects and as a marker of a successful cellular immune response to HCV. Therapeutic expression of IFN-gamma in the liver may therefore facilitate resolution of chronic hepatitis C, an infection that is rarely resolved spontaneously. To analyze immunomodulatory and antiviral effects of liver-specific IFN-gamma expression in vivo, we intravenously injected two persistently HCV-infected chimpanzees twice with a recombinant, replication-deficient HBV vector and subsequently with a recombinant adenoviral vector. These vectors expressed human IFN-gamma under control of HBV- and liver-specific promoters, respectively. Gene transfer resulted in a transient increase of intrahepatic IFN-gamma mRNA, without increase in serum alanine aminotransferase levels. Ex vivo analysis of peripheral blood lymphocytes demonstrated enhanced CD16 expression on T cells and upregulation of the liver-homing marker CXCR3. Moreover, an increased frequency of HCV-specific T cells was detected ex vivo in the peripheral blood and in vitro in liver biopsy-derived, antigen-nonspecifically expanded T-cell lines. None of these immunologic effects were observed in the third chimpanzee injected with an HBV control vector. Despite these immunologic effects of the experimental vector, however, IFN-gamma gene transfer did not result in a significant and long-lasting decrease of HCV titers. In conclusion, liver-directed IFN-gamma gene delivery resulted in HCV-specific and nonspecific activation of cellular immune responses but did not result in effective control of HCV replication.

CCR 4 and CCR 5 expression in conjunctival specimens as differential markers of T(H)1/ T(H)2 in ocular surface disorders

BACKGROUND

Accurate inflammatory mechanisms in chronic ocular surface diseases (OSDs) cannot routinely be assessed. New techniques for investigating ocular surface inflammatory pathways are of major importance.

OBJECTIVE

To investigate the expressions of CCR 4 and CCR 5, known to be related to the T(H)2 and T(H)1 systems, respectively, and HLA-DR in conjunctival impression cytology specimens from patients with chronic OSDs.

METHODS

In this case-controlled study, impression cytology specimens were taken in a series of patients with vernal keratoconjunctivitis (n=21), giant papillary conjunctivitis (n=6), or keratoconjunctivitis sicca (KCS; n=17), or receiving topical antiglaucoma treatments (n=31), and from 20 normal subjects. Conjunctival cells were incubated with mAbs to CCR 4, CCR 5, CD45, and HLA-DR to quantify conjunctival inflammation in a masked manner using flow cytometry.

RESULTS

HLA-DR was higher in the glaucoma and KCS groups than in allergic and normal eyes. CCR 4 was overexpressed in allergy and glaucoma, whereas CCR 5 was higher in the KCS and glaucomatous groups. CD45 was expressed by only few cells in all groups, with almost no significant differences. CCR 4 expression was negatively correlated with CCR 5 and HLA-DR, whereas CCR 5 was positively correlated with HLA-DR.

CONCLUSION

This study confirms the overexpression of chemokine receptors by the conjunctival epithelium in OSDs. CCR 4 and CCR 5 expression may vary according to the immune pathway involved. Accurate mechanisms in ocular surface inflammatory reactions-that is, those related to the T(H)1 or T(H)2 systems-could be differentiated by CCR 4/CCR 5 profiles. Our results also suggest that long-term use of topical treatments may stimulate both systems.

Expression of the chemokine receptor CCR7 in prostate cancer presenting with generalized lymphadenopathy: report of a case, review of the literature, and analysis of chemokine receptor expression

PURPOSE

Generalized lymphadenopathy is a rare presentation of prostate cancer. We report a case and review reported cases in the literature. Because of the association of chemokine receptor expression with specific metastatic patterns, we tested for expression of chemokine receptors known to mediate migration to lymph nodes.

METHODS

We performed a MEDLINE (National Library of Medicine, Bethesda, MD) database search for case reports during the last 32 years using "prostate cancer," "lymphadenopathy," "metastatic to lymph nodes," and "mimicking lymphoma" as keywords. Expression of the CXCR4 and CCR7 chemokine receptors was assessed by immunohistochemistry. Laser capture microdissection and reverse transcription polymerase chain reaction for CXCR4 were used to exclude nonspecific binding.

RESULTS

Of 153 patients with prostate cancer presenting with lymphadenopathy (LAD) described in the literature, 67 (44%) presented with supraclavicular adenopathy, 29 (19%) retroperitoneal, 22 (14%) mediastinal, 15 (10%) cervical, 9 (6%) inguinal, and 2 (1%) axillary LAD. Only 9 patients presenting with generalized LAD have been previously reported. Monoclonal antibodies to CCR7 showed intense staining in the patient's tumor epithelium. Little or no staining was observed for CXCR4. Reverse transcription polymerase chain reaction for chemokine receptors on ribonucleic acid (RNA) recovered from the patient's sample failed to express messenger RNA for CXCR4 but did express messenger RNA for CCR1, CCR4, and CCR5.

CONCLUSIONS

Prostate cancer may present on rare occasions with generalized adenopathy. Variable expression of chemokine receptors may be associated with organ specific patterns of metastasis. In this case, expression of CCR7 may have accounted for the unusual predilection of this patient's prostate cancer for lymph nodes.

Toll-like receptor 4 on nonhematopoietic cells sustains CNS inflammation during endotoxemia, independent of systemic cytokines

Inflammatory agonists such as lipopolysaccharide (LPS) induce robust systemic as well as CNS responses after peripheral administration. Responses in the innate immune system require triggering of toll-like receptor 4 (TLR4), but the origin of CNS sequelas has been controversial. We demonstrate expression of TLR4 transcripts in mouse brain in the meninges, ventricular ependyma, circumventricular organs, along the vasculature, and in parenchymal microglia. The contribution of TLR4 expressed in CNS resident versus hematopoietic cells to the development of CNS inflammation was examined using chimeric mice. Reciprocal bone marrow chimeras between wild-type and TLR4 mutant mice show that TLR4 on CNS resident cells is critically required for sustained inflammation in the brain after systemic LPS administration. Hematopoietic TLR4 alone supported the systemic release of acute phase cytokines, but transcription of proinflammatory genes in the CNS was reduced in duration. In contrast, TLR4 function in radiation-resistant cells was sufficient for inflammatory progression in the brains of chimeric mice, despite the striking absence of cytokine elevations in serum. Surprisingly, a temporal rise in serum corticosterone was also dependent on TLR4 signaling in nonhematopoietic cells. Our findings demonstrate a requirement for TLR4 function in CNS-resident cells, independent of systemic cytokine effects, for sustained CNS-specific inflammation and corticosterone rise during endotoxemia.

Helicobacter pylori-specific CD4+ T cells home to and accumulate in the human Helicobacter pylori-infected gastric mucosa

Helicobacter pylori infects the stomach and duodenal mucosa. T cells are important components of the H. pylori-induced immune response, but little is currently known about how these cells are recruited to the infected mucosa. Here, we have characterized stomach and duodenal T cells isolated from H. pylori-infected and noninfected subjects with regard to subtype, expression of homing and chemokine receptors, and in vitro reactivity to H. pylori antigens. Higher numbers of CD4(+) but similar numbers of CD8(+) lamina propria T cells were isolated from stomach biopsies from H. pylori-positive compared to H. pylori-negative individuals. CD4(+) T cells from infected stomach expressed increased levels of the homing receptor L-selectin and the chemokine receptor CCR4 compared to CD4(+) T cells from uninfected stomach. Infected stomach mucosa also contained increased levels of the CCR4 chemokine ligand MDC/CCL22. In contrast, comparable numbers of CD4(+) T cells with similar receptor expression were isolated from the duodenum of H. pylori-positive and H. pylori-negative individuals. In vitro proliferation of mucosal T cells was strongly enhanced by the addition of interleukin-2 (IL-2) and IL-7 to the cell cultures. Using this approach, H. pylori-specific T-cell responses were detected in stomach CD4(+) T cells from H. pylori-positive but not H. pylori-negative individuals. Duodenal T cells from only a few individuals responded to H. pylori stimulation, and the responsiveness was not restricted to H. pylori-positive individuals, suggesting limited H. pylori specificity in the duodenum and possible cross-reactivity with antigens from other bacteria in this compartment. In conclusion, these results suggest that H. pylori-specific CD4(+) T cells preferentially home to and accumulate in the infected stomach and that L-selectin and CCR4/MDC are important for this recruitment.

Expression analysis of immune-related genes in CD34+ progenitor-derived dendritic cells after exposure to the chemical contact allergen DNCB

We studied the changes in gene expression after exposure of human dendritic cells (DCs) to the model allergen dinitrochlorobenzene (DNCB). DCs were derived from CD34(+) progenitor cells of three different donors and exposed to 10 microM DNCB or solvent for several time intervals (3, 6 and 12h). cDNA microarrays were used to assess the transcriptional activity of 11,000 human genes. Compared to control gene expression, changes larger than +/-two-fold were observed for 241 genes after exposure to DNCB. Of these genes, 137 were up-regulated and 104 down-regulated. Twenty of these genes encode proteins that are related to the immune response (cytokines, chemokines, their receptors, cytokine/chemokines-related genes, transcription and signal transduction genes) and are discussed in more detail. Our data indicate that exposure to DNCB does not induce a typical maturation pattern in DCs.

A Novel Role of CD30/CD30 Ligand Signaling in the Generation of Long-Lived Memory CD8+ T Cells

Memory CD8+ T cells can be divided into two subsets, central memory (T(CM)) and effector memory (T(EM)) CD8+ T cells. We found that CD30, a member of the TNFR-associated factor (TRAF)-linked TNFR superfamily, signaling is involved in differentiation of long-lived CD8+ T(CM) cells following Listeria monocytogenes infection. Although CD8+ T(EM) cells transiently accumulated in the nonlymphoid tissues of CD30 ligand (CD153-/-) mice after infection, long-lived memory CD8+ T(CM) cells were poorly generated in these mice. CCR7 mRNA expression was down-regulated in CD8+ T cells of the spleen of CD153-/- mice in vivo and the expression was up-regulated in CD8+ T(EM) cells by anti-CD30 mAb cross-linking in vitro. These results suggest that CD30/CD30 ligand signaling plays an important role in the generation of long-lived memory CD8+ T cells at least partly by triggering homing receptors for T(CM) cells.

Beta‐chemokine receptors 5 and 3 are expressed on the head region of human spermatozoon

Induction of human sperm chemotaxis is an established phenomenon, though signaling systems physiologically involved have not been identified. Recently, it has been demonstrated that RANTES is present in the follicular fluid and that this molecule is a chemoactractant for human spermatozoa. However, the presence of beta-chemokine receptors on human spermatozoa has never been reported. By cytometric, Western blotting and immunofluorescence analysis, we demonstrate the presence of CCR5 and CCR3 on ejaculated spermatozoa from healthy subjects. CCR5 was detected in the periacrosomal region of the sperm surface, whereas CCR3 was also present in the postacrosomal cap. Individual variability was observed on CCR5 and CCR3 positive sperm percentages. Presence of Delta32+/-) mutation was demonstrated in two subjects expressing CCR5 in half of the ejaculated spermatozoa. Our findings represent the missing information in favor of the possibility that beta-chemokines and their receptors are involved in sperm chemotaxis. Identification of molecular mechanisms of sperm chemotaxis may allow us to identify predictive parameters of sperm fertilizing ability in hypofertile or infertile subjects. Finally, both CCR5 and CCR3 expressed on the sperm cell surface may be involved in HIV-1 adhesion to spermatozoa, thus allowing these cells to perform as virion cellular carriers during sexual transmission of HIV-1 infection.

Accumulation of plasma cells expressing CXCR3 in the synovial sublining regions of early rheumatoid arthritis in association with production of Mig/CXCL9 by synovial fibroblasts

Accumulation of plasma cells in the synovium is one of the diagnostic hallmarks in the histopathological manifestations of rheumatoid arthritis (RA). This seems to be prominent even prior to significant B cell infiltration and/or formation of lymphoid follicles in the synovium. To clarify the mechanism of early plasma cell accumulation, we examined in situ expression of chemokines and their receptors using synovial targeting biopsy specimens, which were obtained under arthroscopy from early RA patients. By immunohistochemical staining, plasma cells were found to express a chemokine receptor CXCR3, while synovial fibroblasts in the synovial sublining regions expressed its ligand, Mig/CXCL9. By reverse transcription-polymerase chain reaction (RT-PCR), using targeted lesions of synovial tissues obtained by laser capture microdissection, expression levels of Mig/CXCL9 in the synovial sublining regions were remarkably high and were likely to be associated with interferon (IFN)-gamma expression. Furthermore, cultured synovial fibroblasts were confirmed to produce Mig/CXCL9 upon stimulation with IFN-gamma. Our results indicate that in the early stage of RA, plasma cells expressing CXCR3 may be recruited directly from the circulation into the synovial sublining regions by its ligand, Mig/CXCL9, produced by synovial fibroblasts.