Secondary Lymphoid Organ Chemokine Research Articles

Targeted Migration of Human Adipose-Derived Stem Cells to Secondary Lymphoid Organs Enhances Their Immunomodulatory Effect and Prolongs the Survival of Allografted Vascularized Composites.

The targeted delivery of therapeutic agents to secondary lymphoid organs (SLOs), which are the niches for immune initiation, provides an unprecedented opportunity for immune intolerance induction. The alloimmune rejection postvascularized composite allotransplantation (VCA) is mediated by T lymphocytes. Human adipose-derived stem cells (hASCs) possess the superiority of convenient availability and potent immunoregulatory property, but their therapeutic results in the VCA are unambiguous thus far. Chemokine receptor 7 (CCR7) can specifically guide immune cells migrating into SLOs. There, the genes of CCR7-GFP or GFP alone were introduced into hASCs by lentivirus. hASCs/CCR7 maintained the multidifferentiation and immunoregulatory abilities, but it gained the migration capacity elicited by secondary lymphoid organ chemokine (SCL) (CCR7 ligand) in vitro. Noteworthily, intravenously infused hASCs/CCR7 targetedly relocated in the T-cell aggression area in SLOs. In a rat VCA model, hASCs/GFP transfusion had a rare effect on the allografted vascularized composite. However, hASCs/CCR7 infusion potently prolonged the grafts' survival time. The ameliorated pathologic exhibition and the regulated inflammatory cytokines in the peripheral blood were also observed. The altered axis of Th1/Th2 and Tregs/Th17 in SLOs may underlie the downregulated rejection response. Moreover, the proteomic examination of splenic T lymphocytes also confirmed that hASCs/CCR7 decreased the proteins related to cytokinesis, lymphocyte proliferation, differentiation, and apoptotic process. In conclusion, our present study demonstrated that targeted migration of hASCs/CCR7 to SLOs highly intensifies their in vivo immunomodulatory effect in the VCA model for the first time. We believe this SLO-targeting strategy may improve the clinical therapeutic efficacy of hASC for allogeneic and autogenic immune disease. Stem Cells 2019;37:1581-1594.

Tissue Cytokine IL-33 Modulates the Cytotoxic CD8 T Lymphocyte Activity During Nutrient Deprivation by Regulation of Lineage-Specific Differentiation Programs.

IL-1 family member IL-33 exerts a variety of immune activating and regulating properties and has recently been proposed as a prognostic biomarker for cancer diseases, although its precise role in tumor immunity is unclear. Here we analyzed in vitro conditions influencing the function of IL-33 as an alarmin and a co-factor for the activity of cytotoxic CD8+ T cells in order to explain the widely discussed promiscuous behavior of IL-33 in vivo. Circulating IL-33 detected in the serum of healthy human volunteers was biologically inactive. Additionally, bioactivity of exogenous recombinant IL-33 was significantly reduced in plasma, suggesting local effects of IL-33, and inactivation in blood. Limited availability of nutrients in tissue causes necrosis and thus favors release of IL-33, which—as described before—leads to a locally high expression of the cytokine. The harsh conditions however influence T cell fitness and their responsiveness to stimuli. Nutrient deprivation and pharmacological inhibition of mTOR mediated a distinctive phenotype characterized by expression of IL-33 receptor ST2L on isolated CD8+ T cells, downregulation of CD8, a transitional CD45RAlowROlow phenotype and high expression of secondary lymphoid organ chemokine receptor CCR7. Under nutrient deprivation, IL-33 inhibited an IL-12 induced increase in granzyme B protein expression and increased expression of GATA3 and FOXP3 mRNA. IL-33 enhanced the TCR-dependent activation of CD8+ T cells and co-stimulated the IL-12/TCR-dependent expression of IFNγ. Respectively, GATA3 and FOXP3 mRNA were not regulated during TCR-dependent activation. TCR-dependent stimulation of PBMC, but not LPS, initiated mRNA expression of soluble IL-33 decoy receptor sST2, a control mechanism limiting IL-33 bioactivity to avoid uncontrolled inflammation. Our findings contribute to the understanding of the compartment-specific activity of IL-33. Furthermore, we newly describe conditions, which promote an IL-33-dependent induction of pro- or anti-inflammatory activity in CD8+ T cells during nutrient deprivation.

IL-10–Modulated Human Dendritic Cells for Clinical Use: Identification of a Stable and Migratory Subset with Improved Tolerogenic Activity

Dendritic cells (DCs) are key regulators of protective immune responses and tolerance to (self-)Ags. Therefore, the scientific rationale for the use of tolerogenic DC therapy in the fields of allergies, autoimmunity, and transplantation medicine is strong. In this study, we analyzed the tolerogenic capacity of IL-10-modulated DC (IL-10DC) subpopulations to identify a DC subset that combines potent immunosuppressive activities with valuable immune properties for clinical implementation. IL-10DCs consist of two phenotypically distinct subpopulations: CD83highCCR7+ IL-10DCs and CD83lowCCR7- IL-10DCs. Suppressor assays with activated effector T cells revealed that CD4+ regulatory T cells generated by CD83high IL-10DCs (iTreg+) exhibited a significantly higher suppressive capacity compared with CD4+ regulatory T cells generated by CD83low IL-10DCs (iTreg-). In this context, iTreg+ displayed a more activated phenotype (proliferation, cytokine production) compared with iTreg- In contrast to CD83low IL-10DCs, CD83high IL-10DCs exerted a strong migratory capacity toward the secondary lymphoid organ chemokine CCL21 and retained a functionally stable phenotype under inflammatory conditions. In addition, CD83high IL-10DCs expressed significantly higher levels of surface and soluble CD25. Functional analysis demonstrated that IL-10DC-related soluble CD25 efficiently inhibited the proliferation of activated T cells and that blockade of CD25 function abolished the induction of regulatory T cells by IL-10DCs, indicating a critical role for IL-10DC-related CD25 in shifting the immune response toward an iTreg- controlled tolerance reaction. In conclusion, the selective use of the CD83high IL-10DC subset may result in a higher efficacy of tolerance induction in vivo and may support the development of novel DC vaccination strategies for transplantations, as well as for allergic and autoimmune diseases.

The Lymphoid Chemokine CCL21 Enhances the Cytotoxic T Lymphocyte-Inducing Functions of Dendritic Cells

The potential use of lymphoid chemokines to generate a dendritic cell (DC) cancer vaccine is not yet clear. We investigated the effect of lymphoid chemokines on DC function and on the production of effective cytotoxic T lymphocytes (CTLs) for application of cancer vaccine using monocyte-derived mature DCs (mDCs) prestimulated with lymphoid chemokines. mDCs exposed to a secondary lymphoid organ chemokine (SLC/CCL21) dramatically induced CTL response by increasing cytolytic activity without any significant alterations on expression of cell surface markers (e.g. CD80, CD83, CD86 and CCR7) or on the production of cytokines (e.g. IL-12p70, IL-10 and IL-23). Interestingly, mDCs prestimulated with CCL21 showed higher levels of CXCL10 (IP-10) production, but not the production of CCL22, compared with untreated mDCs. IP-10 treatment during CTL generation with DCs dramatically enhanced tumour-specific CTL response compared with untreated CTLs, and these enhanced CTL-inducing functions of CCL21-treated DCs were inhibited by anti-IP-10 treatment. Taken together, our data suggested an important role of the lymphoid-endothelium-associated chemokine, CCL21, on DCs in the induction of CTL responses.

The Lymphoid Chemokine CCL21 Enhances the Migration- and CTL-Inducing Functions of Dendritic Cells

Abstract 1127The migration of dendritic cells (DCs) to secondary lymphoid organs is very important to elicit an adaptive immune response in cancer immunotherapy. Here, we show the effect of lymphoid cytokine on the ability of maturing DCs to migrate in response to the lymph node-associated chemokines. The secondary-lymphoid organ chemokine (SLC/CCL21) during DC maturation dramatically enhanced DC migratory capacity responding to CCL21 and CCL19, and, moreover, produced strongly enhanced cytotoxic T cells, although it did not affect the expression of cell surface markers such as CD80, CD83, CD86, and CCR7 and the production of cytokines such as IL-12p70, IL-10, and IL-23. Mature DCs (mDCs) exposed by chemokine produced higher levels of CXCL10 (IP-10) that is one of the chemokines involved in Th1 attraction, but did not affect the production of Th2-attracting cytokine CCL22, compared with unstimulated mDCs. CCL21-exposed DCs induced strongly enhanced numbers of the interferon-g (IFN-g)-expressing antigen-specific CD8+ T cells against tumor-specific antigens in an CXCL10-dependent manner. Cytotoxic CD8+ T cells stimulated with CCL21-exposed DCs expressed higher level of IFN-g than those stimulated with control mDCs. Interestingly, generation of cytotoxic T cells (CTLs) stimulated by TNFa/IL-1b/IL-6/PGE2-treated DCs (sDCs) supplemented with IP-10 produced strong cytotoxic T cells expressing higher level of IFN-g. Tetramer assay showed that CCL21-treated DCs enhanced generation of antigen-specific CTLs. Taken together, our data suggest that mDCs pre-stimulated by chemokine CCL21 enhanced migratory capacity to secondary lymphoid organs and produced strong cytotoxic T cells via IP-10 signaling pathway. Disclosures:No relevant conflicts of interest to declare.

Phase I trial of CCL21 gene modified dendritic cells in non-small cell lung cancer.

TPS157 Background: Intratumoral administration of autologous dendritic cells (DC), transduced with a replication-deficient adenoviral (Ad) vector to express the secondary lymphoid organ chemokine (SLC/CCL21) gene, may stimulate anti-tumor immune responses. Objectives: 1) To determine the safety and maximum tolerated dose (MTD) of CCL21 gene-modified DC (Ad-CCL21-DC) when administered as an intratumoral injection into a tumor site of patients with advanced non-small lung cancer (NSCLC). 2) To determine the local and systemic biologic activity of Ad-CCL21-DC when administered intratumorally to patients with advanced NSCLC. 3) To determine the clinical activity (i.e. reduction in tumor burden) of Ad-CCL21-DC when administered intratumorally to patients with advanced NSCLC. Methods: Study Population: Patients with pathologically confirmed and radiographically measurable NSCLC, stage IIIb/IV, who have tumor accessible by CT-guided intervention or bronchoscopy, and are refractory to standard therapy. Sample Size: 21 patients will be evaluated, 3 patients at each dose level; and an additional 12 patients at the MTD. Study Design: Phase I, nonrandomized, dose escalating, multicohort trial will be conducted to enroll patients at a single institution in a modified 3+3 design. Three patients will be assigned to each cohort (A, B, or C) and receive the same Ad-CCL21-DC dose (1×106, 5×106, or 1×107 cells/injection, respectively) by CT-guided or bronchoscopic intratumoral injection (days 0 and 7). Dose escalation may proceed only if all 3 patients enrolled in the lower dose cohort experience no dose limiting toxicity (DLT) over a 28-day period or 1 of 6 patients in a cohort has a DLT. All subjects will be monitored for 56 days. Eligible patients will be assigned to a cohort and will receive monitoring. Outcome Measures: Tumor biopsy on days 0 and 7: 1) Immunohistochemistry for T cell and DC infiltrates. 2) Quantitative real-time RT-PCR for cytokines. 3) Flow cytometry for T cells, DC, and CCL21. Peripheral blood: 1) Nested PCR for detection of free Ad-CCL21. 2) Quantification of anti-Ad antibody by ELISA. 3) Antigen-specific ELISPOT assays. 4) Quantitate circulating tumor cells. Enrollment: 4 Subjects. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Tragara Pharmaceutical

Lung vascular endothelial growth factor expression induces local myeloid dendritic cell activation

We previously demonstrated that vascular endothelial growth factor (VEGF) expression in the murine lung increases local CD11c+MHCII+ DC number and activation. In this study, employing a multicolor flow cytometry, we report increases in both myeloid (mDC) and plasmacytoid (pDC) DC in the lungs of VEGF transgenic (tg) compared to WT mice. Lung pDC from VEGF tg mice exhibited higher levels of activation with increased expression of MHCII and costimulatory molecules. As VEGF tg mice display an asthma-like phenotype and lung mDC play a critical role in asthmatic setting, studies were undertaken to further characterize murine lung mDC. Evaluations of sorted mDC from VEGF tg lungs demonstrated a selective upregulation of cathepsin K, MMP-8, -9, -12, and -14, and chemokine receptors as compared to those obtained from WT control mice. They also had increased VEGFR2 but downregulated VEGFR1 expression. Analysis of chemokine and regulatory cytokine expression in these cells showed an upregulation of macrophage chemotactic protein-3 (MCP-3), thymus-expressed chemokine (TECK), secondary lymphoid organ chemokine (SLC), macrophage-derived chemokine (MDC), IL-1beta, IL-6, IL-12 and IL-13. The antigen (Ag) OVA-FITC uptake by lung DC and the migration of Ag-loaded DC to local lymph nodes were significantly increased in VEGF tg mice compared to WT mice. Thus, VEGF may predispose the lung to inflammation and/or repair by activating local DC. It regulates lung mDC expression of innate immunity effector molecules. The data presented here demonstrate how lung VEGF expression functionally affects local mDC for the transition from the innate response to a Th2-type inflammatory response.

Permanent Survival of Fully MHC-Mismatched Islet Allografts by Targeting a Single Chemokine Receptor Pathway

Chemokine receptor blockade can diminish the recruitment of host effector cells and prolong allograft survival, but little is known of the role of chemokine receptors in promoting host sensitization. We engrafted fully allogeneic islets into streptozotocin-treated normal mice or mice with the autosomal recessive paucity of lymph node T cell (plt) mutation; the latter lack secondary lymphoid expression of the CCR7 ligands, secondary lymphoid organ chemokine (CCL21) and EBV-induced molecule-1 ligand chemokine (CCL19). plt mice showed permanent survival of islets engrafted under the kidney capsule, whereas controls rejected islet allografts in 12 days (p < 0.001), and consistent with this, plt mice had normal allogeneic T cell responses, but deficient migration of donor dendritic cell to draining lymph nodes. Peritransplant i.v. injection of donor splenocytes caused plt recipients to reject their allografts by 12 days, and sensitization at 60 days posttransplant of plt mice with well-functioning allografts restored acute rejection. Finally, islet allografts transplanted intrahepatically in plt mice were rejected approximately 12 days posttransplant, like controls, as were primarily revascularized cardiac allografts. These data show that the chemokine-directed homing of donor dendritic cell to secondary lymphoid tissues is essential for host sensitization and allograft rejection. Interruption of such homing can prevent T cell priming and islet allograft rejection despite normal T and B cell functions of the recipient, with potential clinical implications.

Is secondary lymphoid-organ chemokine (SLC/CCL21) much more than a constitutive chemokine?

Chemokines are a superfamily of small cytokines with activities ranging from leukocyte traffick to hematopoiesis, angiogenesis, and tissue organogenesis. Secondary lymphoid-organ chemokine (SLC/CCL21) was originally reported as a chemokine constitutively expressed by stromal cells and high endothelial venules in secondary lymphoid tissues and endothelium of afferent lymphatics, directing CCR7+ cells. More recently, others and we have demonstrated that SLC/CCL21 is up-regulated in different skin inflammatory conditions. Thereafter, this molecule is much more than a constitutive chemokine, which could play a role in effector and regulatory immune functions.

Gene duplications at the chemokine locus on mouse chromosome 4: multiple strain-specific haplotypes and the deletion of secondary lymphoid-organ chemokine and EBI-1 ligand chemokine genes in the plt mutation.

The murine paucity of lymph node T cell (plt) mutation leads to abnormalities in leukocyte migration and immune response. The causative defect is thought to be a loss of secondary lymphoid-organ chemokine (SLC) expression in lymphoid tissues. We now find that the plt defect is due to the loss of both SLC and EBI-1 ligand chemokine (ELC) expression in secondary lymphoid organs. In an examination of the plt locus, we find that commonly used inbred mouse strains demonstrate at least three different haplotypes. Polymorphism at this locus is due to duplications of at least four genes, three of them encoding chemokines. At least two cutaneous T cell-attracting chemokine (CTACK), three SLC, and four ELC genes or pseudogenes are present in some haplotypes. All haplotypes share a duplication that includes two SLC genes, which demonstrate different expression patterns, a single functional ELC gene, and an ELC pseudogene. The plt mutation represents a deletion that includes the SLC gene expressed in secondary lymphoid organs and the single functional ELC gene, leaving only an SLC gene that is expressed in lymphatic endothelium and an ELC pseudogene. This lack of CCR7 ligands in the secondary lymphoid organs of plt mice provides a basis for their severe abnormalities in leukocyte migration and immune response.

Regulation by chemokines of circulating dendritic cell precursors, and the formation of portal tract-associated lymphoid tissue, in a granulomatous liver disease.

We have studied the recruitment and roles of distinct dendritic cell (DC) precursors from the circulation into Propionibacterium acnes-induced granulomas in mouse liver. During infection, F4/80(-)B220(-)CD11c(+) DC precursors appeared in the circulation, migrated into the perisinusoidal space, and matured within newly formed granulomas. Recruited DCs later migrated to the portal area to interact with T cells in what we term "portal tract-associated lymphoid tissue" (PALT). Macrophage inflammatory protein 1alpha attracted blood DC precursors to the sinusoidal granuloma, whereas secondary lymphoid organ chemokine (SLC) attracted mature DCs to the newly identified PALT. Anti-SLC antibody diminished PALT expansion while exacerbating granuloma formation. Therefore, circulating DC precursors can migrate into a solid organ like liver, and participate in the granulomatous reaction in response to specific chemokines.

Coexpression of the chemokines ELC and SLC by T zone stromal cells and deletion of the ELC gene in the plt/plt mouse.

The spontaneous mutant mouse strain, plt/plt, lacks the secondary lymphoid organ chemokine (SLC)-ser gene and has disrupted trafficking of T cells and dendritic cells (DCs) to lymphoid tissues. We demonstrate here that the gene for the related chemokine, Epstein-Barr virus-induced molecule-1 ligand chemokine (ELC), is also deleted in this immunodeficient mouse strain. Using a combination of approaches, including bone marrow reconstitution and double in situ hybridization, we show in wild-type mice that ELC is expressed by T zone stromal cells that also make SLC. Smaller amounts of ELC are made by DCs, predominantly of the CD8(+) phenotype. We propose that ELC- and SLC-expressing T zone stromal cells play a central role in bringing naive T cells and DCs together for the initiation of immune responses.

Localization of distinct Peyer's patch dendritic cell subsets and their recruitment by chemokines macrophage inflammatory protein (MIP)-3alpha, MIP-3beta, and secondary lymphoid organ chemokine.

We describe the anatomical localization of three distinct dendritic cell (DC) subsets in the murine Peyer's patch (PP) and explore the role of chemokines in their recruitment. By two-color in situ immunofluorescence, CD11b(+) myeloid DCs were determined to be present in the subepithelial dome (SED) region, whereas CD8alpha(+) lymphoid DCs are present in the T cell-rich interfollicular region (IFR). DCs that lack expression of CD8alpha or CD11b (double negative) are present in both the SED and IFR. By in situ hybridization, macrophage inflammatory protein (MIP)-3alpha mRNA was dramatically expressed only by the follicle-associated epithelium overlying the SED, while its receptor, CCR6, was concentrated in the SED. In contrast, CCR7 was expressed predominantly in the IFR. Consistent with these findings, reverse transcriptase polymerase chain reaction analysis and in vitro chemotaxis assays using freshly isolated DCs revealed that CCR6 was functionally expressed only by DC subsets present in the SED, while all subsets expressed functional CCR7. Moreover, none of the splenic DC subsets migrated toward MIP-3alpha. These data support a distinct role for MIP-3alpha/CCR6 in recruitment of CD11b(+) DCs toward the mucosal surfaces and for MIP-3beta/CCR7 in attraction of CD8alpha(+) DCs to the T cell regions. Finally, we demonstrated that all DC subsets expressed an immature phenotype when freshly isolated and maintained expression of subset markers upon maturation in vitro. In contrast, CCR7 expression by myeloid PP DCs was enhanced with maturation in vitro. In addition, this subset disappeared from the SED and appeared in the IFR after microbial stimulation in vivo, suggesting that immature myeloid SED DCs capture antigens and migrate to IFR to initiate T cell responses after mucosal microbial infections.

Mice lacking expression of secondary lymphoid organ chemokine have defects in lymphocyte homing and dendritic cell localization.

Secondary lymphoid organ chemokine (SLC) is expressed in high endothelial venules and in T cell zones of spleen and lymph nodes (LNs) and strongly attracts naive T cells. In mice homozygous for the paucity of lymph node T cell (plt) mutation, naive T cells fail to home to LNs or the lymphoid regions of spleen. Here we demonstrate that expression of SLC is undetectable in plt mice. In addition to the defect in T cell homing, we demonstrate that dendritic cells (DCs) fail to accumulate in spleen and LN T cell zones of plt mice. DC migration to LNs after contact sensitization is also substantially reduced. The physiologic significance of these abnormalities in plt mice is indicated by a markedly increased sensitivity to infection with murine hepatitis virus. The plt mutation maps to the SLC locus; however, the sequence of SLC introns and exons in plt mice is normal. These findings suggest that the abnormalities in plt mice are due to a genetic defect in the expression of SLC and that SLC mediates the entry of naive T cells and antigen-stimulated DCs into the T cell zones of secondary lymphoid organs.