Visualizing Synaptic Transfer of Tumor Antigens among Dendritic Cells.

Generation of tumor-infiltrating lymphocytes begins when tumor antigens reach the lymph node (LN) to stimulate T cells, yet we know little of how tumor material is disseminated among the large variety of antigen-presenting dendritic cell (DC) subsets in the LN. Here, we demonstrate that tumor proteins are carried to the LN within discrete vesicles inside DCs and are then transferred among DC subsets. A synapse is formed between interacting DCs and vesicle transfer takes place in the absence of free exosomes. DCs -containing vesicles can uniquely activate T cells, whereas DCs lacking them do not. Understanding this restricted sharing of tumor identity provides substantial room for engineering better anti-tumor immunity.

C-C Motif Chemokine Receptor 7 Exacerbates Hypertension Through Effects on T Lymphocyte Trafficking.

Activated T lymphocytes that infiltrate blood pressure control organs make a critical contribution to the pathogenesis of hypertension. Dendritic cells act as potent antigen-presenting cells to stimulate prohypertensive T cells. However, the mechanisms that facilitate the recruitment of prohypertensive T cells and dendritic cells into the kidney's draining lymph node during hypertension require elucidation. As CCR7 (C-C motif chemokine receptor type 7) directs the homing of lymphocytes and dendritic cells into lymph nodes, we posited that dendritic cell-mediated T lymphocyte stimulation in the renal lymph node is CCR7 dependent and required for a full hypertensive response. We found that CCR7-deficient (CCR7 KO) mice had a blunted hypertensive response in our model of chronic Ang II (angiotensin II) infusion. Ang II-infused CCR7 KO animals had exaggerated accumulation of CD8+ T cells in the kidney but reduced numbers of CD4+ and CD8+ T cells in the kidney's draining lymph node. To understand whether CCR7-dependent homing of T lymphocytes or dendritic cells into the lymph node regulates the hypertensive response, we injected CCR7 KO or wild-type T cells or dendritic cells into CCR7 KO recipients, neither of which restored the full hypertensive response to Ang II infusion. However, adoptive transfer of wild-type but not CCR7 KO T lymphocytes into RAG1 (recombination-activating gene 1)-deficient mice that lack a lymphocyte niche restored full blood pressure elevation during Ang II infusion. Thus, CCR7-dependent interactions between T lymphocytes and dendritic cells are essential for T lymphocyte stimulation and hypertension accruing from inappropriate activation of the renin-angiotensin system.

RAGE and CCR7 mediate the transmigration of Zika-infected monocytes through the blood-brain barrier.

Details of the "Trojan Horse" mechanism by which Zika virus (ZIKV) crosses the blood-brain barrier (BBB) remain unclear. However, the migration of ZIKV-infected monocytes to the brain is thought to be dependent on both pattern-recognition and chemokine receptors. In this study, we investigated whether the migration of ZIKV-infected MonoMac-1 (MM-1) cells through the BBB is dependent on chemokine receptor 7 (CCR7) and receptor for advanced glycation end (RAGE); we also determined whether high mobility group box protein 1 (HMGB1) could facilitate the permeabilization of endothelial cells. We demonstrated that ZIKV infects MM-1 cells, leading to milieu accumulation of HMGB1. Our results suggest that HMGB1 is involved in the dysregulation of primary human brain microvascular endothelial cell junction markers. Our results also indicate that the migration of ZIKV-infected monocytes is dependent on chemokine ligand 19 (CCL19), the natural ligand of CCR7, in conditions recapitulating inflammation. RAGE-dependent migration of ZIKV-infected cells declined during transmigration assays in the presence of RAGE receptor antagonist FPS-ZM1. Understanding the molecular role of monocyte trafficking during ZIKV infections could facilitate the development of new therapeutic strategies to prevent the deleterious consequences of ZIKV neuroinfection.

Autologous Hematopoietic Stem Cells Are a Preferred Source to Generate Dendritic Cells for Immunotherapy in Multiple Myeloma Patients.

In multiple myeloma (MM), dendritic cells (DCs), and their precursors are prone to malignant cell-mediated regulation of function leading to low efficacy of DC vaccine. DCs taken directly from MM patient's body or derived from monocytes are fewer in numbers and are also dysfunctional. Here, we investigated the functionality of Hematopoietic stem cell-derived DCs (SC-DCs) from MM patients. Mature-MM-SC-DCs showed all essential functions like antigen uptake, allogenic T cells simulation and migration comparable to those derived from healthy donor (HD) samples. A comparison of Mo-DCs and SC-DCs obtained from the same MM patients' samples revealed that the expression of IL-6 was higher in the precursors of Mo-DCs leading to their impaired migration. In addition, expression of CCR7 which is responsible for DCs migration was found to be lower in MM-Mo-DCs. The chromatin permissiveness as observed by H3K4me3 histone modification at the Ccr7 promoter in MM-Mo-DCs was significantly lower than those in MM-SC-DCs. Levels of Zbtb46- a hall mark DC transcription factor mRNA was also found to be reduced in MM-Mo-DCs. Cytotoxic T cells generated from MM-SC-DCs from autologous naïve T cells exhibited reduced antitumor activity because the T cells were exhausted. Blocking of CTLA-4 on autologous T cells could partially restore T cell proliferation and activation. Thus, a combination of MM-SC-DC vaccine and anti-CTLA-4 antibody may serve as a better candidate for immunotherapy of MM. This study has implications in increasing the efficacy of cancer immunotherapy in MM.

Tumor necrosis factor-α induces prostate cancer cell migration in lymphatic metastasis through CCR7 upregulation.

Understanding the mechanism of lymph node metastasis, a poor prognostic sign for prostate cancer, and the further dissemination of the disease is important to develop novel treatment strategies. Recent studies have reported that C-C chemokine receptor 7 (CCR7), whose ligand is CCL21, is abundantly expressed in lymph node metastasis and promotes cancer progression. Tumor necrosis factor-α (TNF-α) is chronically produced at low levels within the tumor microenvironment. The aim of this study was to determine whether TNF-α promotes prostate cancer dissemination from metastatic lymph nodes through activation of the CCL21/CCR7 axis. First, human prostate cancer cells were determined to express both TNF-α and CCR7. Second, low concentrations of TNF-α were confirmed to induce CCR7 in prostate cancer cells through phosphorylation of ERK. Finally, CCL21 was found to promote the migration of prostate cancer cells through phosphorylation of the protein kinase p38. Our results suggest that TNF-α leads to the induction of CCR7 expression and that the CCL21/CCR7 axis might increase the metastatic potential of prostate cancer cells in lymph node metastasis.

Airway eosinophil migration into lymph nodes in mice depends on leukotriene C4.

BACKGROUND: We previously demonstrated in mice that airway eosinophils traffic from the airway lumen into lung-draining paratracheal lymph nodes. However, mechanisms whereby eosinophils traverse from the lungs and home to paratracheal lymph nodes remain unclear. We investigated roles of cysteinyl leukotrienes in mediating eosinophil trafficking from lungs to paratracheal lymph nodes. METHODS: The expression of CCR7 was determined by flow cytometry. Transwell assays were used to test chemotactic responses of leukotriene C4 synthase-deficient and control airway eosinophils to the chemokine CCL19 ex vivo. Eosinophils from the spleens of IL-5 transgenic mice, fluorescently labeled ex vivo, were intratracheally injected into ovalbumin-sensitized and ovalbumin aerosol-challenged leukotriene C4 synthase-deficient and control mice. Eosinophils were identified by microscopy and flow cytometry in the lungs and paratracheal lymph nodes. RESULTS: Mouse eosinophils expressed CCR7, the receptor for CCL19, and responded chemotactically to CCL19. Leukotriene C4 synthase-deficient eosinophils exhibited impaired chemotaxis to CCL19 that was restored by exogenous leukotriene C4 . The migration of intratracheally injected eosinophils into paratracheal lymph nodes from distal alveolar lung was diminished in leukotriene C4 synthase-deficient mice compared with wild-type mice, with increased retention of eosinophils in the lungs of leukotriene C4 synthase-deficient mice. Exogenous administration of leukotriene C4 restored trafficking of eosinophils to paratracheal lymph nodes in leukotriene C4 synthase-deficient mice. CONCLUSIONS: Our findings that cysteinyl leukotrienes are involved in regulating airway and lung eosinophil migration into paratracheal lymph nodes identify previously unrecognized roles for the cysteinyl leukotrienes in regulating the pulmonary trafficking of eosinophils in experimental allergic asthma.

New development in studies of formyl-peptide receptors: critical roles in host defense.

Formyl-peptide receptors are a family of 7 transmembrane domain, Gi-protein-coupled receptors that possess multiple functions in many pathophysiologic processes because of their expression in a variety of cell types and their capacity to interact with a variety of structurally diverse, chemotactic ligands. Accumulating evidence demonstrates that formyl-peptide receptors are critical mediators of myeloid cell trafficking in the sequential chemotaxis signal relays in microbial infection, inflammation, and immune responses. Formyl-peptide receptors are also involved in the development and progression of cancer. In addition, one of the formyl-peptide receptor family members, Fpr2, is expressed by normal mouse-colon epithelial cells, mediates cell responses to microbial chemotactic agonists, participates in mucosal development and repair, and protects against inflammation-associated tumorigenesis. These novel discoveries greatly expanded the current understanding of the role of formyl-peptide receptors in host defense and as potential molecular targets for the development of therapeutics.

CCR4 promotes medullary entry and thymocyte-dendritic cell interactions required for central tolerance.

Autoimmunity results from a breakdown in central or peripheral tolerance. To establish central tolerance, developing T cells must enter the thymic medulla, where they scan antigen-presenting cells (APCs) displaying a diverse array of autoantigens. If a thymocyte is activated by a self-antigen, the cell undergoes either deletion or diversion into the regulatory T cell (T reg) lineage, thus maintaining self-tolerance. Mechanisms promoting thymocyte medullary entry and interactions with APCs are incompletely understood. CCR4 is poised to contribute to central tolerance due to its expression by post-positive selection thymocytes, and expression of its ligands by medullary thymic dendritic cells (DCs). Here, we use two-photon time-lapse microscopy to demonstrate that CCR4 promotes medullary entry of the earliest post-positive selection thymocytes, as well as efficient interactions between medullary thymocytes and DCs. In keeping with the contribution of thymic DCs to central tolerance, CCR4 is involved in regulating negative selection of polyclonal and T cell receptor (TCR) transgenic thymocytes. In the absence of CCR4, autoreactive T cells accumulate in secondary lymphoid organs and autoimmunity ensues. These studies reveal a previously unappreciated role for CCR4 in the establishment of central tolerance.

Elevated IFN-alpha/beta levels in a streptozotocin-induced type I diabetic mouse model promote oxidative stress and mediate depletion of spleen-homing CD8+ T cells by apoptosis through impaired CCL21/CCR7 axis and IL-7/CD127 signaling.

Type 1 diabetes mellitus (T1D) is associated with increased type 1 interferon (IFN) levels and subsequent severe defects in lymphocyte function, which increase susceptibility to infections. The blockade of type 1 IFN receptor 1 (IFNAR1) in non-obese diabetic mice has been shown to delay T1D onset and decrease T1D incidence by enhancing spleen CD4+ T cells and restoring B cell function. However, the effect of type 1 IFN blockade during T1D on splenic CD8+ T cells has not previously been studied. Therefore, we investigated, for the first time, the effect of IFNAR1 blockade on the survival and architecture of spleen-homing CD8+ T cells in a streptozotocin-induced T1D mouse model. Three groups of mice were examined: a non-diabetic control group; a diabetic group; and a diabetic group treated with an anti-IFNAR1 blocking antibody. We observed that T1D induction was accompanied by a marked destruction of ß cells followed by a marked reduction in insulin levels and increased IFN-α and IFN-ß levels in the diabetic group. The diabetic mice also exhibited many abnormal changes including an elevation in blood and spleen free radical (reactive oxygen species and nitric oxide) and pro-inflammatory cytokine (IL-6 and TNF-α) levels, a significant decrease in IL-7 levels, and subsequently, a significant decrease in the numbers of spleen-homing CD8+ T cells. This decrease in spleen-homing CD8+ T cells resulted from a marked reduction in the CCL21-mediated entry of CD8+ T cells into the spleen and from increased apoptosis due to a marked reduction in IL-7-mediated STAT5 and AKT phosphorylation. Interestingly, type 1 IFN signaling blockade in diabetic mice significantly restored the numbers of splenic CD8+ T cells by restoring free radical, pro-inflammatory cytokine and IL-7 levels. These effects subsequently rescued splenic CD8+ T cells from apoptosis through a mechanism that was dependent upon CCL21- and IL-7-mediated signaling. Our data suggest that type 1 IFN is an essential mediator of pathogenesis in T1D and that this role results from the negative effect of IFN signaling on the survival of splenic CD8+ T cells.

CCR7 is involved in BCR-ABL/STAP-2-mediated cell growth in hematopoietic Ba/F3 cells.

Chronic myeloid leukemia is a clonal disease characterized by the presence of the Philadelphia chromosome and its oncogenic product, BCR-ABL, which activates multiple pathways involved in cell survival, growth promotion, and disease progression. We previously reported that in murine hematopoietic Ba/F3 cells, signal transducing adaptor protein-2 (STAP-2) binds to BCR-ABL and up-regulates BCR-ABL phosphorylation, leading to enhanced activation of its downstream signaling molecules. The binding of STAP-2 to BCR-ABL also influenced the expression levels of chemokine receptors, such as CXCR4 and CCR7. For the induction of CCR7 expression, signals mediated by the MAPK/ERK pathway were critical in Ba/F3 cells expressing BCR-ABL and STAP-2. In addition, STAP-2 cooperated with BCR-ABL to induce the production of CCR7 ligands, CCL19 and CCL21. Our results demonstrate a contribution of CCR7 to STAP-2-dependent enhancement of BCR-ABL-mediated cell growth in Ba/F3 cells.

Correlation between CCR7 expression and lymph node metastatic potential of human tongue carcinoma.

Metastasis is an important cause of cancer-related mortality. In this study, we investigated the role of CCR7 in the lymph node metastasis of tongue carcinoma. Immunohistochemistry and Western blot revealed the expression of CCR7 in tongue SCC tissues and cell lines. In addition, we examined the expression of CCL21, a ligand of CCR7, in normal and diseased lymph nodes using immunohistochemistry and/or real-time PCR. The CCR7 expression was significantly correlated with cervical lymph node metastasis, tumor staging, and histological grade (P = 0.015, 0.040, and 0.015, respectively). The multivariate analysis showed that regional lymph node metastasis, the expression of CCR7, and LVD were the independent poor prognostic factors. Knockdown of CCR7 gene resulted in a significant inhibition of migration and invasion of SCC4 cells in vitro without affecting the proliferation and apoptosis of tumor cells. Also, CCR7 knockdown obviously inhibited cervical lymph node metastasis in an animal tumor model. Our study indicated that CCR7 may play an important role in progression of tongue SCC and could be a promising target for tongue SCC therapy.

CCR7 expressing mesenchymal stem cells potently inhibit graft-versus-host disease by spoiling the fourth supplemental Billingham's tenet.

The clinical acute graft-versus-host disease (GvHD)-therapy of mesenchymal stem cells (MSCs) is not as satisfactory as expected. Secondary lymphoid organs (SLOs) are the major niches serve to initiate immune responses or induce tolerance. Our previous study showed that CCR7 guide murine MSC line C3H10T1/2 migrating to SLOs. In this study, CCR7 gene was engineered into murine MSCs by lentivirus transfection system (MSCs/CCR7). The immunomodulatory mechanism of MSCs/CCR7 was further investigated. Provoked by inflammatory cytokines, MSCs/CCR7 increased the secretion of nitric oxide and calmed down the T cell immune response in vitro. Immunofluorescent staining results showed that transfused MSCs/CCR7 can migrate to and relocate at the appropriate T cell-rich zones within SLOs in vivo. MSCs/CCR7 displayed enhanced effect in prolonging the survival and alleviating the clinical scores of the GvHD mice than normal MSCs. Owing to the critical relocation sites, MSCs/CCR7 co-infusion potently made the T cells in SLOs more naïve like, thus control T cells trafficking from SLOs to the target organs. Through spoiling the fourth supplemental Billingham's tenet, MSCs/CCR7 potently inhibited the development of GvHD. The study here provides a novel therapeutic strategy of MSCs/CCR7 infusion at a low dosage to give potent immunomodulatory effect for clinical immune disease therapy.

CCR7 is critical for the induction and maintenance of Th17 immunity in dry eye disease.

PURPOSE: We characterized antigen-presenting cell (APC)-relevant chemokine receptor expression in dry eye disease (DED), and investigated the effect of topical CC chemokine receptor (CCR)-7 blockade specifically on Th17 cell immunity and dry eye disease severity. METHODS: We induced DED in female C57BL/6 mice. Chemokine receptor expression by corneal APCs was characterized using immunohistochemistry. To determine the functional role of CCR7 in DED, mice were treated topically with either anti-CCR7, a control isotype antibody, or left untreated, and clinical disease severity, Th17 responses, and molecular markers of DED were quantified. RESULTS: Frequencies of CD11b(+) cells and their chemokine expression were increased in the cornea of DED mice. Mice treated topically with anti-CCR7 antibody displayed a significant reduction in clinical disease severity and Th17 response compared to the isotype and untreated groups. Topical CCR7 blockade was effective in ameliorating DED in its acute and chronic stages. CONCLUSIONS: Our findings suggest that CCR7-mediated trafficking of APCs drives the induction and maintenance of Th17 immunity in DED and that CCR7 blockade is effective in suppressing the immunopathogenic mechanisms in DED.

Differential requirement for CCR4 and CCR7 during the development of innate and adaptive αßT cells in the adult thymus.

αßT cell development depends upon serial migration of thymocyte precursors through cortical and medullary microenvironments, enabling specialized stromal cells to provide important signals at specific stages of their development. Although conventional αßT cells are subject to clonal deletion in the medulla, entry into the thymus medulla also fosters αßT cell differentiation. For example, during postnatal periods, the medulla is involved in the intrathymic generation of multiple αßT cell lineages, notably the induction of Foxp3(+) regulatory T cell development and the completion of invariant NKT cell development. Although migration of conventional αßT cells to the medulla is mediated by the chemokine receptor CCR7, how other T cell subsets gain access to medullary areas during their normal development is not clear. In this study, we show that combining a panel of thymocyte maturation markers with cell surface analysis of CCR7 and CCR4 identifies distinct stages in the development of multiple αßT cell lineages in the thymus. Although Aire regulates expression of the CCR4 ligands CCL17 and CCL22, we show that CCR4 is dispensable for thymocyte migration and development in the adult thymus, demonstrating defective T cell development in Aire(-/-) mice is not because of a loss of CCR4-mediated migration. Moreover, we reveal that CCR7 controls the development of invariant NKT cells by enabling their access to IL-15 trans-presentation in the thymic medulla and influences the balance of early and late intrathymic stages of Foxp3(+) regulatory T cell development. Collectively, our data identify novel roles for CCR7 during intrathymic T cell development, highlighting its importance in enabling multiple αßT cell lineages to access the thymic medulla.

Contribution of homeostatic chemokines CCL19 and CCL21 and their receptor CCR7 to coronary artery disease.

OBJECTIVE: Our aim was to identify the role of the homeostatic chemokines CCL19 and CCL21 and their common receptor CCR7 in atherogenesis and to study the relationships between CCL19, CCL21, and CCR7 gene variants and coronary artery disease in a Chinese Han population. APPROACH AND RESULTS: Immunohistochemical analysis of samples with atherosclerosis of various stages showed increased CCL19, CCL21, and CCR7 expression in atherosclerotic coronary plaques compared with nonatherosclerotic controls. Expression levels increased in positive correlation with coronary lesion stage. Cell adhesion assays confirmed that CCL19 promoted monocyte adhesion, which was induced by CCR7, to human umbilical vein endothelial cells, an effect partially antagonized by atorvastatin. After the human umbilical vein endothelial cells were treated with CCR7-neutralizing antibody, both CCL19- and CCL21-induced monocyte to human umbilical vein endothelial cell migration and CCL19-induced monocyte to human umbilical vein endothelial cell adhesion were abolished. The associations between genetic variants of CCL19, CCL21, CCR7, and coronary artery disease in a Chinese Han population were determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The following single nucleotide polymorphisms were associated with coronary artery disease: CCL19 rs2227302, CCL21 rs2812377, and CCR7 rs588019. Individuals with the CCL19 rs2227302 T allele or CCL21 rs2812377 G allele had higher plasma CCL19 levels than those with C/C genotype and higher CCL21 levels than those with T/T genotype in both case and control subjects. CONCLUSION: CCL19/CCL21-CCR7 is a novel homeostatic chemokine system that modulates human monocyte adhesion and migration, promoting atherogenesis. It is associated with coronary artery disease risk in Chinese Han individuals. These data suggest that the CCL19/CCL21-CCR7 axis plays an important role in atherosclerosis progression.

LXR-dependent and -independent effects of oxysterols on immunity and tumor growth.

Oxysterols are involved in maintaining cellular cholesterol levels. Recently, oxysterols have been demonstrated to modulate the function of immune cells and tumor growth. These effects can be dependent on the activation of the oxysterol-binding liver X receptors (LXRs) or, as recently demonstrated for T and B cells, DCs and neutrophils, can be independent of LXR activation. LXR-dependent oxysterol effects can be ascribed to the activation of LXRα, LXRß or LXRαß isoforms, which induces transcriptional activation or trans-repression of target genes. The prevalent activation of one isoform seems to be cell-, tissue-, or context-specific, as shown in some pathologic processes, i.e., infectious diseases, atherosclerosis, and autoimmunity. Oxysterol-LXR signaling has recently been shown to inhibit antitumor immune responses, as well as to modulate tumor cell growth. Here, we review the mechanisms that link oxysterols to tumor growth, and discuss possible networks at the basis of LXR-dependent and -independent oxysterol effects on immune cells and tumor development.

CCR7 guides migration of mesenchymal stem cell to secondary lymphoid organs: a novel approach to separate GvHD from GvL effect.

Inefficient homing of systemically infused mesenchymal stem cells (MSCs) limits the efficacy of existing MSC-based clinical graft-versus-host disease (GvHD) therapies. Secondary lymphoid organs (SLOs) are the major niches for generating immune responses or tolerance. MSCs home to a wide range of organs, but rarely to SLOs after intravenous infusion. Thus, we hypothesized that targeted migration of MSCs into SLOs may significantly improve their immunomodulatory effect. Here, chemokine receptor 7 (CCR7) gene, encoding a receptor that specifically guides migration of immune cells into SLOs, was engineered into a murine MSC line C3H10T1/2 by retrovirus transfection system (MSCs/CCR7). We found that infusion of MSCs/CCR7 potently prolonged the survival of GvHD mouse model. The infused MSCs/CCR7 migrate to SLOs, relocate in proximity with T lymphocytes, therefore, potently inhibited their proliferation, activation, and cytotoxicity. Natural killer (NK) cells contribute to the early control of leukemia relapse. Although MSCs/CCR7 inhibited NK cell activity in vitro coculture, they did not impact on the proportion and cytotoxic capacities of NK cells in the peripheral blood of GvHD mice. In an EL4 leukemia cell loaded GvHD model, MSCs/CCR7 infusion preserved the graft-versus-leukemia (GvL) effect. In conclusion, this study demonstrates that CCR7 guides migration of MSCs to SLOs and thus highly intensify their in vivo immunomodulatory effect while preserving the GvL activity. This exciting therapeutic strategy may improve the clinical efficacy of MSC based therapy for immune diseases.

The absence of CCR7 results in dysregulated monocyte migration and immunosuppression facilitating chronic cutaneous leishmaniasis.

The protozoan parasite Leishmania major causes cutaneous lesions to develop at the site of infection, which are resolved with a strong Th1 immune response in resistant hosts, such as C57BL/6 mice. In contrast, the lesions ulcerate in susceptible hosts which display a Th2 response, such as BALB/c mice. The migration of cells in the immune response to L. major is regulated by chemokines and their receptors. The chemokine receptor CCR7 is expressed on activated DCs and naïve T cells, allowing them to migrate to the correct micro-anatomical positions within secondary lymphoid organs. While there have been many studies on the function of CCR7 during homeostasis or using model antigens, there are very few studies on the role of CCR7 during infection. In this study, we show that B6.CCR7(-/-) mice were unable to resolve the lesion and developed a chronic disease. The composition of the local infiltrate at the lesion was significantly skewed toward neutrophils while the proportion of CCR2(+) monocytes was reduced. Furthermore, a greater percentage of CCR2(+) monocytes expressed CCR7 in the footpad than in the lymph node or spleen of B6.WT mice. We also found an increased percentage of regulatory T cells in the draining lymph node of B6.CCR7(-/-) mice throughout infection. Additionally, the cytokine milieu of the lymph node showed a Th2 bias, rather than the resistant Th1 phenotype. This data shows that CCR7 is required for a protective immune response to intracellular L. major infection.

CCL19/CCR7 upregulates heparanase via specificity protein-1 (Sp1) to promote invasion of cell in lung cancer.

CCL19/chemokine receptor 7 (CCR7) has been found to be associated with tumor growth, angiogenesis, invasion, and lymph node metastasis. Our previous study demonstrated that CCR7 overexpressed in non-small cell lung cancer (NSCLC) and had close relationship with tumor invasion and lymph node metastasis. However, the molecular mechanism of CCR7 promoting invasion of human NSCLC cells is still unclear. In this study, we demonstrated that human lung adenocarcinoma A549 cells treated with recombinant human CCL19 could obviously upregulate the expression of Sp1 and heparanase at both the mRNA and protein levels. After blockage of CCR7, Sp1 and heparanase expressions were inhibited. Following inhibition of Sp1, heparanase expression was downregulated. The analysis showed the promoter region of heparanase gene containing a number of potential sp1 binding sites (5'-GGGGC-3'). Chromatin immunoprecipitation analysis demonstrated that Sp1 could bind to the heparanase promoter. Cell invasion assays showed that the invasion ability of A549 cells was increased with CCL19 incubation compared to the control cells. These results suggested that CCL19/CCR7 may upregulate the expression of heparanase via Sp1 and contribute to the invasion of A549 cells.

A myriad of functions and complex regulation of the CCR7/CCL19/CCL21 chemokine axis in the adaptive immune system.

The chemokine receptor CCR7 and its ligands CCL19 and CCL21 control a diverse array of migratory events in adaptive immune function. Most prominently, CCR7 promotes homing of T cells and DCs to T cell areas of lymphoid tissues where T cell priming occurs. However, CCR7 and its ligands also contribute to a multitude of adaptive immune functions including thymocyte development, secondary lymphoid organogenesis, high affinity antibody responses, regulatory and memory T cell function, and lymphocyte egress from tissues. In this survey, we summarise the role of CCR7 in adaptive immunity and describe recent progress in understanding how this axis is regulated. In particular we highlight CCX-CKR, which scavenges both CCR7 ligands, and discuss its emerging significance in the immune system.