Higher Expression Of CCR7 Research Articles

Fms-Like Tyrosine Kinase 3 Ligand Regulates Migratory Pattern and Antigen Uptake of Lung Dendritic Cell Subsets in a Murine Model of Allergic Airway Inflammation

Fms-like tyrosine kinase 3 ligand (Flt3L) reverses the features of allergic airway inflammation and increases a Th2-suppressive regulatory lung CD11c(high)CD11b(low) dendritic cell (DC) subset in a mouse model. We examined the migratory pattern and Ag uptake efficiency of lung DC subsets in the therapeutic effect of Flt3L. Lung CD11c(high)CD11b(low) and CD11c(low)CD11b(high) DCs from PBS-treated, OVA-sensitized, and Flt3L-treated/OVA-sensitized BALB/c mice were sorted using MACS and FACS for phenotype analysis. Lymphatic chemokine expression in thoracic lymph nodes was determined by immunohistochemistry. Migration of two lung DC subsets to lymphatic chemokines was examined in vitro using a Transwell chemotaxis assay. Labeled Ag was intranasally delivered into mouse lung to track the migration and Ag uptake of lung DCs. The in vitro cytokine secretion of mediastinal lymph node cells was determined using ELISA. CD11c(low)CD11b(high) DCs have higher expression of CCR5, CCR6, and CCR7, but lower expression of CCR2 than CD11c(high)CD11b(low) DCs. CD11c(low)CD11b(high) DCs in Flt3L-treated/OVA-sensitized mice demonstrated a less mature phenotype, inefficiency in Ag uptake, and impaired migration in vitro to lymphatic chemokine than those in OVA-sensitized mice. Administration of Flt3L decreased the expression of CCR5 and CCR7 in CD11c(low)CD11b(high) DCs in OVA-sensitized mice. Fewer Ag-carrying cells were detected in the lungs and lymph nodes in Flt3L-treated/OVA-sensitized mice than OVA-sensitized mice with a greater decrease in CD11c(low)CD11b(high) DCs. Mediastinal lymph node cells from Flt3L-treated mice secreted higher levels of Th1 cytokines and IL-10 than OVA-sensitized mice in vitro. In conclusion, Flt3L-generated lung immunogenic CD11c(low)CD11b(high) DCs have a less mature phenotype, impaired Ag uptake, and impaired migration to draining lymph nodes.

High CCR7 mRNA expression of cancer cells is associated with lymph node involvement in patients with esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (SCC) is one of the biological malignant tumors. Once a tumor invades the submucosa, an incidence of lymph node (LN) metastases is very high, thus resulting in poor survival. Recently, chemokines have been reported to play an important role in organ-specific metastases in several malignancies. In particular, CCR7 has been reported to be associated with LN metastases by immunohistochemistry. However, there have been no studies of quantitative analyses of CCR7 mRNA expression on cancer cells. In this study, we investigated the clinical significance of the expression of CCR7 in the establishment of LN metastases of esophageal SCC. A series of 78 patients with esophageal SCC who underwent esophagectomy were consecutively selected. The expression of CCR7 mRNA from tumor tissue samples was analyzed by quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), and that from cancer cell samples collected using laser microdissection system was analyzed by qRT-PCR. Immunohistochemical staining of CCR7 was also performed. Although CCR7 mRNA expression in tumor tissues demonstrated no association with the LN metastases, that in cancer cells correlated with LN metastases (p<0.05) due to the fact that not only cancer cells but also infiltrating lymphocytes expressed CCR7 in tumor tissue. Multivariate logistic regression analysis revealed a high CCR7 expression in cancer cells to be an independent predictive factor for LN metastases. These results suggested that CCR7 expression might play an important role in establishing LN metastases in patients with esophageal SCC.

Induction of high expression of CCR7 and high production of IL-12 in human monocyte-derived dendritic cells by a new bacterial component: LCOS 1013

Dendritic cells (DCs) are the most potent antigen presenting cells of the immune system as they can act as initiators, stimulators and regulators of the immune response. Human DCs are most commonly generated for clinical use by in vitro differentiation of monocytes with exogenous cytokines. Here, we investigate the effect of LCOS 1013 on the production of mature Mo-DCs. LCOS 1013 is a new bacterial component from walls of gram + Klebsellia pneumoniae bacteria that contain some OmpA glycoproteins. Purified peripheral blood monocytes were cultured for 6 days with IL-4 and GM-CSF in order to obtain immature dendritic cells (Im-MoDCs). On day six, Im-MoDCs were matured with either LCOS 1013, TNF alpha, LPS or CD40-Ligand. LCOS 1013 matured Mo-DCs (LCO-DCs) showed a higher expression of DC-LAMP, CD80, CD83, CD54 and CD40 than TNF alpha, LPS and CD40L matured Mo-DCs. Interestingly, LCO-DCs exhibited high expression of full competent CCR7 and high secretion of IL-12 during their maturation. Functionally, LCO-DCs have equivalent potency to trigger mixed leukocyte reaction and antigen-specific reaction and polarize immune response towards Th1 way. Moreover, we found that LCOS 1013 activates DCs through TLR2. LCOS 1013 represents an attractive therapeutic maturation agent of DCs allowing the production of Mo-DCs with high capacity to migrate and to induced Th1 immune responses.

Lung adenocarcinoma invasion in TGFβRII-deficient cells is mediated by CCL5/RANTES

Recently, we identified a lung adenocarcinoma signature that segregated tumors into three clades distinguished by histological invasiveness. Among the genes differentially expressed was the type II transforming growth factor-beta receptor (TGFbetaRII), which was lower in adenocarcinoma mixed subtype and solid invasive subtype tumors compared with bronchioloalveolar carcinoma. We used a tumor cell invasion system to identify the chemokine CCL5 (RANTES, regulated on activation, normal T-cell expressed and presumably secreted) as a potential downstream mediator of TGF-beta signaling important for lung adenocarcinoma invasion. We specifically hypothesized that RANTES is required for lung cancer invasion and progression in TGFbetaRII-repressed cells. We examined invasion in TGFbetaRII-deficient cells treated with two inhibitors of RANTES activity, Met-RANTES and a CCR5 receptor-blocking antibody. Both treatments blocked invasion induced by TGFbetaRII knockdown. In addition, we examined the clinical relevance of the RANTES-CCR5 pathway by establishing an association of RANTES and CCR5 immunostaining with invasion and outcome in human lung adenocarcinoma specimens. Moderate or high expression of both RANTES and CCR5 was associated with an increased risk for death, P=0.014 and 0.002, respectively. In conclusion, our studies indicate RANTES signaling is required for invasion in TGFbetaRII-deficient cells and suggest a role for CCR5 inhibition in lung adenocarcinoma prevention and treatment.

The CD16+ Monocyte Subset Is More Permissive to Infection and Preferentially Harbors HIV-1 In Vivo

HIV-1 persists in peripheral blood monocytes in individuals receiving highly active antiretroviral therapy (HAART) with viral suppression, despite these cells being poorly susceptible to infection in vitro. Because very few monocytes harbor HIV-1 in vivo, we considered whether a subset of monocytes might be more permissive to infection. We show that a minor CD16+ monocyte subset preferentially harbors HIV-1 in infected individuals on HAART when compared with the majority of monocytes (CD14highCD16-). We confirmed this by in vitro experiments showing that CD16+ monocytes were more susceptible to CCR5-using strains of HIV-1, a finding that is associated with higher CCR5 expression on these cells. CD16+ monocytes were also more permissive to infection with a vesicular stomatitis virus G protein-pseudotyped reporter strain of HIV-1 than the majority of monocytes, suggesting that they are better able to support HIV-1 replication after entry. Consistent with this observation, high molecular mass complexes of apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G (APOBEC3G) were observed in CD16+ monocytes that were similar to those observed in highly permissive T cells. In contrast, CD14highCD16- monocytes contained low molecular mass active APOBEC3G, suggesting this is a mechanism of resistance to HIV-1 infection in these cells. Collectively, these data show that CD16+ monocytes are preferentially susceptible to HIV-1 entry, more permissive for replication, and constitute a continuing source of viral persistence during HAART.

Intestinal double positive CD4+CD8+ T cells of neonates are highly activated memory cells with higher proliferative capacity compared to single positive CD4+/CD8+ T cells (B115)

Abstract Peripheral blood and thymic double positive CD4+CD8+ (DP) T cells from neonates have been described in humans and a number of animals, but the function and immunophenotypic characteristics of other tissue-derived DP T cells are not clearly understood. Here we demonstrate the phenotypic characteristics of DP cells in 6 different tissues including thymus from normal neonatal rhesus macaques (Macaca mulatta) between 0–21 days of age. In general, DP T cells of neonates have higher percentages of memory markers (CD28+CD95+, CD45RA−) compared to single positive (SP) CD4+ and CD8+ T cells. In addition, intestinal DP T cells increase as the animals’ age and levels of CD62L decrease with age suggesting that DP cells proliferate and are activated with maturity and/or antigen exposure. Consistent with this, intestinal DP T cells in neonates express higher levels of activation markers and CCR5 expression. Furthermore, DP T cells have higher rates of proliferation compared to SP CD4+ and SP CD8+ T cells as determined by BrdU labelling techniques. Finally, DP T cells produce higher levels of cytokine production in response to mitogen stimulation compared to SP CD4+ or SP CD8+ T cells. Collectively, these findings demonstrate that intestinal DP T cells of neonates are proliferating, effector cells and are likely involved in regulating immune as compared to the immature DP T cells in the thymus. As in adults, these intestinal DP T cells may be important target cells for early HIV infection in neonates due to their activation, high expression of CCR5, and memory phenotype.

Initial Events in Establishing Vaginal Entry and Infection by Human Immunodeficiency Virus Type-1

SummaryUnderstanding the initial events in the establishment of vaginal human immunodeficiency virus type-1 (HIV-1) entry and infection has been hampered by the lack of appropriate experimental models. Here, we show in an ex vivo human organ culture system that upon contact in situ, HIV-1 rapidly penetrated both intraepithelial vaginal Langerhans and CD4+ T cells. HIV-1 entered CD4+ T cells almost exclusively by CD4 and CCR5 receptor-mediated direct fusion, without requiring passage from Langerhans cells, and overt productive infection ensued. By contrast, HIV-1 entered CD1a+ Langerhans cells primarily by endocytosis, by means of multiple receptors, and virions persisted intact within the cytoplasm for several days. Our findings shed light on the very earliest steps of mucosal HIV infection in vivo and may guide the design of effective strategies to block local transmission and prevent HIV-1 spread.

CCR5 Chemokine Receptor Expression Can Promote Disease Progression in Non-Hodgkin's Lymphoma.

Background: Non-Hodgkin's lymphomas (nHL) represent heterogenous group of lymphoid malignancies derived from B and T lymphocytes, NK cells or histiocytes. Most of lymphomas are B-cell origin. Lymphoma cells can migrate to other organs and their migration could be linked to chemokines and their receptors. Chemokine receptors are expressed by many cell populations, including lymphoid cells, and their function is mediation of trafficking and localization particularly lymphocytes. CCR5 is predominantly expressed on Th1 cells, but also on dendritic cells, fibroblasts, endothelial and epithelial cells. Up-regulation of CCR5 expression is typical for nonneoplastic leukocytic infiltrates of nodal Hodgkin lymphoma. Its expression has been shown in hairy cell leukemia (HCL) and mantle cell lymphoma (MCL).Aim: The purpose of this study was to determine CCR5 expression in lymph nodes derived from patients with nHL comparing to control reactive lymph nodes and if there was any correlation between CCR5 expression and proliferation marker Ki-67 and international prognostic index (IPI).Material and methods: CCR5 gene expression was determined in 37 lymph nodes of lymphoma patients (26 B-cell lymphoma: 12 females and 14 males aged 26–73 years; 4 T-cell lymphoma: males aged 41–81 years; 7 Hodgkin's lymphoma: 4 females and 3 males aged 21–58 years) and 25 reactive lymph nodes (15 females, 10 males, aged 18–59 years, median age 32 years). Gene expression was determined by the reverse transcription (RT)-polymerase chain reaction method. Scale of expression was 0–3 AU. Statistical analysis was performed using Kruskall-Wallis and Mann-Witney tests (p<0,05).Results: Most of lymphoma lymph nodes (25/37) showed low CCR5 expression (0–1 AU). In reactive lymph nodes 18/25 had also low CCR5 expression. In B-cell lymphomas high CCR5 expression characterized HCL, Burkitt's lymphoma and diffuse large B-cell lymphoma nodes. In pts with higher CCR5 expression there was positive correlation with Ki-67 proliferation marker (p=0,016; coefficient = 0,34) and IPI (p=0,047; coefficient = 0,298).Conclusions: As there is a positive correlation between CCR5 expression and Ki-67 proliferation marker and IPI in non-Hodgkin's lymphoma lymph nodes CCR5 may be associated with lymphoma progression.

Distinct Phenotype of Chronic Lymphocytic Leukaemia (B-CLL) Cells Engrafting in NOD/SCID Mice.

We have previously reported reliable engraftment of CD19/CD5/CD23/CD45 positive human B-CLL cells in the spleens of NOD/SCID mice (NSS-CLL cells) following transplantation of human peripheral blood-derived B-CLL (PB-CLL) cells. On histology, in the majority of the samples NSS-CLL cells formed focal aggregates which also contained various amounts (range:0–50%) of human CD45/CD3+ T cells (ASH 2005; #52). We now have further characterized these NSS-CLL cells. In our model 1x10^8 MNC are injected i.v. plus i.p. and engraftment in the spleen and other organs is analyzed after 4 (−8) weeks by flow cytometry and immunohistochemistry. In 22 CLL samples investigated in a total of 64 NOD/SCID mice 1.6±0.4x106 NSS-CLL cells representing 10.5±2.3% of total spleen cells were recovered with recovery highly reproducible on repetitive experiments (3.0 vs. 2.0; 1.6 vs. 1.5; 0.2 vs. 1.1; 0.0 vs. 0.0x106 NSS-CLL cells; n=4). In contrast to the low proliferative status reported for human PB-CLL, considerable proliferation was observed in NSS-CLL cells. Following the application of BrdU (1mg/6g d5 i.p., 1mg/ml added to drinking water d6–13; 20–27) BrdU positive NSS-CLL cells ranged from 5.3–25.0% (n=5). Immunohistological analysis showed positive staining for the proliferation marker Ki67 in 18.5±3.5% of NSS-CLL cells. In addition, markers related to proliferation/activation of B-CLL proliferation center cells such as survivin (mean MFI: 5.5±0.8 vs. 2.3±0.2; p=0.028; n=6) and CD100 (semaphorin 4d; mean MFI: 3.3±0.5 vs. 1.1±0.2; p=0.043; n=5) were significantly up-regulated in NSS-CLL vs. PB-CLL cells. When NSS-CLL cells were characterized utilizing additional adhesion/migration, differentiation and/or activation markers, only a subset of NSS-CLL cells (15.7±8.2%, n=6) expressed chemokine coreceptor (CCR) 7, while PB-CLL cells uniformly showed high CCR7 expression. Also CCR5, a migration marker in the context of non-Hodgkin lymphomas, consistently was demonstrated on a fraction of NSS-CLL cells (8.1±3.0%; n=6), whereas here no CCR5 expression was found on PB-CLL cells. No expression of human CD10, CD11c, CD127 or CD49d was detected in B-CLL cells derived from either PB- or NSS-CLL cells, while both sources, as expected, uniformly stained positive for CD40. In summary, NSS-CLL exibit a distinct phenotype as compared to PB-CLL cells and show considerable similarity to B-CLL cells in the proliferation centers of involved human tissues. For these cells not only proliferation but also increased expression of survivin and CD100 as well as down-regulation of CCR7 have been described. Therefore, we think that our model may represent a novel tool to further elucidate biological properties of human B-CLL and, in addition, may serve to devise and evaluate novel treatment strategies.

CCR5 expression and duration of high risk sexual activity among HIV-seronegative men who have sex with men

To test the hypothesis that in comparison with those with shorter risk duration, individuals with longer HIV risk duration would have reduced susceptibility to HIV-1 infection as measured by CCR5 expression, and to evaluate whether variation in CCR5 expression could be explained by known genetic polymorphisms. A cross-sectional study of HIV-1 exposed but uninfected men who have sex with men. The risk duration was estimated from self-reported years since first receptive anal intercourse. CCR5 expression on peripheral blood CD4+ monocytes and T cells was determined by flow cytometry. The CCR5-Delta32 mutation and polymorphisms in the CCR5 promoter and CCR2 as well as the copy number of CCL3L1 were analyzed by polymerase chain reaction. Plasma levels of MIP-1alpha (CCL3), MIP-1beta (CCL4) and RANTES (CCL5) were also measured. As risk duration varied with age, analyses were restricted to 67 individuals aged 30-49 years. Multiple linear regression analyses, adjusted for age and race, showed a significant negative association between HIV risk duration and CCR5 expression on monocytes (P = 0.01), and in a separate model, a similar negative association with CCR5 expression on T cells (P = 0.03). Low CCR5 expression was attributable mainly to CCR5-Delta32 heterozygosity and the CCR5-59029G allele. We confirmed a role for reduced CCR5 expression in HIV-1 resistance. CCR5-Delta32 heterozygosity and the CCR5-59029G allele were significant predictors of low CCR5 expression. Individuals with high CCR5 expression who resisted infection despite long HIV risk duration form an interesting group within which to search for additional mechanisms of resistance to HIV infection.

CCR5 and the natural history of HIV infection

The human immunodeficiency virus type 1 (HIV-1) uses, in addition to the CD4 molecule, a chemokine receptor as a receptor to infect T lymphocytes. Most viral strains use the chemokine receptor CCR5 as a coreceptor. The density of CCR5 molecules on CD4+ T cells varies widely among individuals, but is constant over time for a given individual. Infected subjects with high CCR5 expression present high viral load, progress rapidly, respond poorly to antiretroviral therapies, and have high viral rebond after treatment interruption. This is due to the fact that in cells expressing high surface CCR5 densities, the binding of the virus to its coreceptor triggers strong activation signals, that transit through Gai proteins, and facilitate the reverse transcription of the viral RNA. Thus, CCR5 is not only a dock for HIV-1 but also a choke preparing the target cell to replicate the virus. This model could explain intercellular variabilities in infectibility by differences in the capacity of the virus to activate the cell it infects. Moreover, this model opens new therapeutic opportunities targeting the pathways activated by the virus for his advantage.

Intestinal double‐positive CD4+CD8+ T cells are highly activated memory cells with an increased capacity to produce cytokines

Peripheral blood and intestinal CD4+CD8+ double-positive (DP) T cells have been described in several species including humans, but their function and immunophenotypic characteristics are still not clearly understood. Here we demonstrate that DP T cells are abundant in the intestinal lamina propria of normal rhesus macaques (Macaca mulatta). Moreover, DP T cells have a memory phenotype and are capable of producing different and/or higher levels of cytokines and chemokines in response to mitogen stimulation compared to CD4+ single-positive T cells. Intestinal DP T cells are also highly activated and have higher expression of CCR5, which makes them preferred targets for simian immunodeficiency virus/HIV infection. Increased levels of CD69, CD25 and HLA-DR, and lower CD62L expression were found on intestinal DP T cells populations compared to CD4+ single-positive T cells. Collectively, these findings demonstrate that intestinal and peripheral blood DP T cells are effector cells and may be important in regulating immune responses, which distinguishes them from the immature DP cells found in the thymus. Finally, these intestinal DP T cells may be important target cells for HIV infection and replication due to their activation, memory phenotype and high expression of CCR5.

Triptolide, a constituent of immunosuppressive Chinese herbal medicine, is a potent suppressor of dendritic-cell maturation and trafficking

AbstractTriptolide (TPT) is a chemically defined, potent immunosuppressive compound isolated from an anti-inflammatory Chinese herbal medicine. TPT has been reported to inhibit autoimmunity, allograft rejection, and graft-versus-host disease (GVHD), and its efficacy was previously attributed to the suppression of T cells. Since dendritic cells (DCs) play a major role in the initiation of T-cell–mediated immunity, we studied the effects of TPT on the phenotype, function, and migration of human monocyte–derived DCs. TPT treatment, over a pharmacologic concentration range, inhibited the lipopolysaccharide (LPS)–induced phenotypic changes, characteristic of mature DCs and the production of interleukin-12p70 (IL-12p70). Consequently, the allostimulatory functions of DCs were impaired by TPT treatment. Furthermore, the calcium mobilization and chemotactic responses of LPS-stimulated DCs to secondary lymphoid tissue chemokine (SLC)/CC chemokine ligand 21 (CCL21) were significantly lower in TPT-treated than untreated DCs, in association with lower chemokine receptor 7 (CCR7) and higher CCR5 expression. Egress of Langerhans cells (LCs) from explanted mouse skin in response to macrophage inflammatory protein-3β (MIP-3β)/CCL19 was arrested by TPT. In vivo administration of TPT markedly inhibited hapten (fluorescein isothiocyanate [FITC])–stimulated migration of mouse skin LCs to the draining lymph nodes. These data provide new insight into the mechanism of action of TPT and indicate that the inhibition of maturation and trafficking of DCs by TPT contributes to its immunosuppressive effects.

Isolation of TAK-779-resistant HIV-1 from an R5 HIV-1 GP120 V3 Loop Library

The human immunodeficiency virus (HIV-1) envelope glycoprotein (GP) 120 interacts with CD4 and the CCR5 coreceptor for viral entry. The V3 loop in GP120 is a crucial region for determining coreceptor usage during viral entry, and a variety of amino acid substitutions has been observed in clinical isolates. To construct an HIV-1 V3 loop library, we chose 10 amino acid positions in the V3 loop and incorporated random combinations (27,648 possibilities) of the amino acid substitutions derived from 31 R5 viruses into the V3 loop of HIV-1(JR-FL) proviral DNA. The constructed HIV-1 library contained 6.6 x 10(6) independent clones containing a set of 0-10 amino acid substitutions in the V3 loop. To address whether restricted steric alteration in the V3 loop could confer resistance to an entry inhibitor, TAK-779, we selected entry inhibitor-resistant HIV-1 by increasing the concentration of TAK-779 from 0.10 to 0.30 microM in PM1-CCR5 cells with high expression of CCR5. The selected viruses at passage 8 contained five amino acid substitutions in the V3 loop without any other mutations in GP120 and showed 15-fold resistance compared with the parental virus. These results indicated that a certain structure of the V3 loop containing amino acid substitutions derived from 31 R5 viruses can contribute to the acquisition of resistance to entry inhibitors binding to CCR5. Taken together, this type of HIV-1 V3 loop library is useful for isolating and analyzing the specific biological features of HIV-1 with respect to alterations of the V3 loop structure.

골수 유래 기질 줄기세포의 탐식작용 매개성 케모카인 수용체 발현 연구

To design gene deliver systems which can deliver higher amounts of genes into stem cells, we studied the expression of receptors involved in the receptor-mediated endocytosis of bone marrow stromal stem cells. Bone marrow was isolated from ICR mice, and bone marrow stromal stem cells were isolated based on their plastic adherence property. Several culture conditions were screened for effective and continuous culture of marrow stromal stem cells. MesenCult medium was finally used to cultivate marrow stromal stem cells in vitro. As candidate receptors, various chemokine receptors were studied. Both bone marrow cells ad marrow-derived stromal stem cells showed expression of CC chemokine receptors (CCR) and CXC chemokine receptors (CXCR). Marrow stromal stem cells showed higher expression of CCR5 ad CXCR4 chemokine receptors as compared to other types of chemokine receptors. Moreover, though the expression of chemokine receptors generally decreased in most chemokine receptors with the cultivaton of marrow stromal stem cells, CCR5 and CXCR4 chemokine receptors retained the higher level of receptor expressions over prolonged periods. These results suggest that the ligands exhibiting specific binding to CCR5 or CXCR4 might be used to modify gene delivery systems for increased levels of receptor-mediated gene delivery into stromal stem cells.

Kinetics of CCR7 expression differ between primary activation and effector memory states of T H1 and T H2 cells

We explored the kinetics of CCR7 expression on T H1 and T H2 polarized cells as well as on antigen-specific T cell lines at various stages of differentiation. A striking pattern of early (days 7–14) inducible CCR7 expression was seen preferentially on primary T H1 cell lines, as compared to T H2 cells, and was dependent on the strength and duration of the T cell receptor signal. Upon repeated restimulation (days 21–28) and differentiation, a switch occurred in which T H2 cells had high CCR7 expression, whereas T H1 cells lost CCR7 expression. Chronic (8 weeks and later) effector memory cell lines were 95% CCR7 negative. These data demonstrate an ordered pattern of CCR7 expression that suggest more rapid priming of T H1 cells in the lymph node, and delayed priming with prolonged CCR7 expression during T H2 responses, and may have implications for tracking T H1 effector T cells ex vivo in autoimmune diseases.

Regulation of CCR5 expression and MIP-1α production in CD4+ T cells from patients with rheumatoid arthritis

Production of CCR5 expression and MIP-1alpha, a ligand of CCR5, by CD4+ T cells from patients with rheumatoid arthritis (RA) were studied. We analysed further the influence of IL-15 stimulation, CD40/CD40 ligand (CD40L) interaction and CCR5 promotor polymorphism. One hundred and fifty-five RA patients and another 155 age- and sex-matched healthy individuals were enrolled. Peripheral CD4+ and double negative (DN) T cells from patients had lower portions of CCR5, whereas synovial CD4+ and DN T cells showed a much higher CCR5 expression. IL-15 significantly up-regulated the expression of CCR5 on purified CD4+ T cells. CD40L expression on synovial CD4+ T cells was increased greatly in CCR5+ portions by IL-15. MIP-1alpha production by synovial CD4+ T cells was also enhanced by IL-15. Co-culture of CD40 expressing synovial fibroblasts with IL-15-activated synovial CD4+ T cells significantly increased MIP-1alpha production. Expression of CCR5 on patients' CD4+ T cells was not influenced by the promotor polymorphism of CCR5 gene. Taken together, these data suggest CCR5+CD4+ T cells infiltrate the inflamed synovium and IL-15 up-regulates CCR5 and CD40L expression further and enhance MIP-1alpha production in synovial CD4+ T cells. Production of MIP-1alpha by synovial fibroblasts is significantly increased by engagement of CD40 with CD40L. Synovial microenvironment plays a potential role in regulation of CCR5+CD4+ T cells in rheumatoid joints.

Uncoupling of inflammatory chemokine receptors by IL-10: generation of functional decoys.

As originally demonstrated for the interleukin 1 (IL-1) type II receptor, some primary proinflammatory cytokines from the IL-1 and tumor necrosis factor families are regulated by decoy receptors that are structurally incapable of signaling. Here we report that concomitant exposure to proinflammatory signals and IL-10 generates functional decoy receptors in the chemokine system. Inflammatory signals, which cause dendritic cell (DC) maturation and migration to lymphoid organs, induce a chemokine receptor switch, with down-regulation of inflammatory receptors (such as CCR1, CCR2, CCR5) and induction of CCR7. Concomitant exposure to lipopolysaccharide (LPS) and IL-10 blocks the chemokine receptor switch associated with DC maturation. LPS + IL-10-treated DCs showed low expression of CCR7 and high expression of CCR1, CCR2 and CCR5. These receptors were unable to elicit migration. We provide evidence that uncoupled receptors, expressed on LPS + IL-10-treated cells, sequester and scavenge inflammatory chemokines. Similar results were obtained for monocytes exposed to activating signals and IL-10. Thus, in an inflammatory environment, IL-10 generates functional decoy receptors on DC and monocytes, which act as molecular sinks and scavengers for inflammatory chemokines.

Selective recruitment of polarized T cells expressing CCR5 and CXCR3 to the inflamed joints of children with juvenile idiopathic arthritis.

To study the expression of chemokine receptors CCR5 and CXCR3 and the Th1/Th2 cytokine balance in children with oligoarticular or polyarticular juvenile idiopathic arthritis (JIA). Using 3-color immunofluorescence, we studied the expression of CCR5 and CXCR3 on, and T cell cytokine production by, paired samples of synovial fluid (SF) and peripheral blood (PB) T cells from 20 patients with oligoarticular- or polyarticular-onset JIA. Chemokine and cytokine phenotypes were also compared within the CD45RO+,CD3+ subsets. CCR5 genotypes were confirmed by polymerase chain reaction typing and sequencing. In the majority of samples, the number of T cells that were CCR5+ and CXCR3+ was higher in SF than in PB, and this difference was significant. One child was homozygous for the null A32 CCR5 allele; 4 others had lower expression of CXCR3 in SF than in blood. All samples showed strongly Th1-type cytokine production by synovial T cells compared with that by PB T cells. Both features were also markedly polarized within the synovial CD45RO+ subset compared with PB CD45RO+ T cells. The high expression of CCR5 and CXCR3 and high interferon-gamma:interleukin-4 ratios suggest a type 1 phenotype of SF T cells in JIA. The difference between CD45RO+ T cells from SF and from PB suggests that specific activation events have occurred in synovial T cells. We suggest that the highly activated, Th1-type phenotype of T cells within the chronically inflamed joints of children with JIA may reflect specific recruitment events that contribute to the polarization of these cells.

Expression of Chemokine Receptors CXCR4 and CCR5 in HIV-1-Infected and Uninfected Individuals

The chemokine receptors CXCR4 and CCR5 have been identified as major coreceptors for HIV-1 entry into CD4+ T cells. The majority of primary HIV-1 isolates in early disease use CCR5 as a coreceptor, whereas during disease progression with the emergence of syncytium-inducing viruses, CXCR4 is also used. We performed a cross-sectional study in which we evaluated the expression of two HIV-1 coreceptors, CCR5 and CXCR4, in whole blood samples taken from HIV-1-infected and uninfected individuals. We demonstrate that CXCR4 on CD4+ and CD8+ T cells, and CD14+ monocytes is significantly down-regulated, and CCR5 expression on CD4+ T cells is up-regulated in HIV-infected individuals compared with uninfected controls. Coreceptor expression correlated with the level of cellular activation in vivo in both HIV-infected and uninfected individuals, with CXCR4 being expressed predominantly on quiescent (HLA-DR-) T cells and CCR5 being expressed predominantly on activated (HLA-DR+) T cells. Lower expression of CXCR4 and higher expression of CCR5 on CD4+ T cells correlated with advancing disease. In addition, a tendency for greater activation of CXCR4+CD4+ T cells in patients with advanced disease was observed. Patients who harbored syncytium-inducing viruses, however, could not be distinguished from those who harbored nonsyncytium-inducing viruses based on the level of CD4+ T cell activation or chemokine receptor expression.