Cell Chemokine Receptor Expression Research Articles

Role of non-canonical T cells in homeostasis and pathology

In addition to the subsets of T lymphocytes and innate lymphocytes (innate lymphoid cells), the well-known players in adaptive immunity, there is an intermediate group of lymphocytes (innate-like cells) that already possess the T cell receptor, but with a restricted repertoire. This group includes γδT cells, subsets of type I and II NKT cells carrying both T cell receptor and NK-cell receptors, and mucosal-associated invariant T (MAIT) cells. The development of innate-like cells occurs in the thymus, but their positive and negative selection takes place without the participation of thymic epithelial cells. A distinctive feature is that innate-like cells acquire an effector phenotype already in the thymus, and therefore do not require complex activation reactions during antigen recognition. Upon exit from the thymus, noncanonical T cells express chemokine receptors, allowing them to migrate into barrier tissues at an early age. A characteristic feature of the T cell receptor innate-like cells is the recognition of non-peptide antigens presented in non-polymorphic histocompatibility molecules (MHC-Ib). This type of molecule includes the CD1 a/b/c/d/e molecule and the MR1 molecule. These molecules present lipid, glycolipid antigens and metabolites of B vitamins, synthesized by various representatives of the microbiota. The presence of functionally different subpopulations of innate-like cells with an activated phenotype allows them to quickly respond to the antigen by producing cytokines typical of Th1, Th2, Th17. They also exhibit cytotoxic and immunoregulatory activity. These cells are actively involved in regulation of barrier tissue homeostasis and interaction with microbiota. They synthesize growth factors for epithelial cells, fibroblasts, and vascular endothelium, which are required for regeneration of damaged tissues. They also participate in anti-infectious defense, directing the development of the immune response. Moreover, they have been found to be involved in many autoimmune diseases. The special functions of innate-like cells make them a promising target for therapeutic interventions. It has been shown that antibiotics, salicylates and some other well-known drugs exert certain effects on the innate-like cells. Different dietary options also affect the activity of these cells.

Impact of azithromycin on the migration of peripheral blood T lymphocytes from patients with chronic obstructive pulmonary disease to RANTES and IP-10

The inflammatory process specific for chronic obstructive pulmonary disease (COPD) is accompanied by T lymphocyte migration from peripheral blood to the respiratory tract. Suppression of T cell chemotaxis by drugs may attenuate the inflammatory response in patients with COPD.The aim of this study was to determine the ability of azithromycin in combination with glucocorticoids to affect the migration of blood T cells in patients with COPD.The percentage of T lymphocytes expressing chemokine receptors CCR5, CCR6, CCR7, CXCR3, CXCR4, CXCR6 was analyzed by flow cytometry in the peripheral blood of 54 smokers with COPD, 21 healthy smokers, and 20 healthy non-smokers, as well as in bronchoalveolar lavage (BAL) of 7 smokers with COPD and 7 healthy smokers. Additionally, we determined the effect of azithromycin (10 μg/ml) and budesonide (10 nM) on the migration of peripheral blood T helper cells and cytotoxic T lymphocytes from patients with COPD (n = 8) to chemokines RANTES (10 nM) and IP-10 (10 nM).The percentage of T lymphocytes expressing chemokine receptors CXCR3 and CCR5 increased in the peripheral blood of COPD smokers compared with healthy smokers and healthy non-smokers, as well as in the BAL of COPD smokers compared with healthy smokers. The proportion of T cells expressing chemokine receptors CXCR4, CXCR6, CCR6, and CCR7 did not differ in the peripheral blood and the BAL between COPD patients and healthy controls. Budesonide only inhibited the migration of cytotoxic T lymphocytes to RANTES. Azithromycin, alone and combined with budesonide, inhibited the migration of T helper cells and cytotoxic T lymphocytes to both RANTES and IP-10. Moreover, the inhibitory effect of azithromycin, in combination with budesonide and without it, on the T cell migration was significantly greater than the effect of budesonide alone.Our results suggest a role for CXCR3 and CCR5 in T cell recruitment into the lungs of COPD patients and demonstrate the ability of azithromycin to inhibit T lymphocyte migration.

Abstract 2649: Orally bioavailable small molecule CXCR4 antagonists with enhanced efficacy in mouse models of genitourinary cancers

Abstract Purpose: Pro-angiogenic and immune cells expressing chemokine receptor CXCR4 traffic along concentration gradients of the chemokine ligand CXCL12, which disseminates from stromal niches. The CXCR4/CXCL12 axis is hijacked by various cancer types characterized by dramatic CXCR4 and/or CXCL12 upregulation. This chemokine network misregulation causes hyperactivation of CXCR4-mediated processes, leading to (1) excessive stimulation of protective tumor-stromal interactions, (2) metastatic expansion of CXCR4+ cancer cells to CXCL12-rich sites, and (3) intratumoral infiltration of CXCR4+ immunosuppressive cells. Accordingly, CXCR4 antagonists have significant therapeutic potential against cancer. While clinical CXCR4 inhibitors are severely limited by suboptimal pharmacokinetic (PK) properties and off-target activities, several of our tetrahydroisoquinoline-based CXCR4 antagonists exhibit superior selectivity and PK profiles to these clinical comparators (e.g., X4P-001). Methods: To test the hypothesis that improved PK profiles would translate to enhanced efficacy, our lead CXCR4 antagonist EMU-116 was compared to X4P-001 head-to-head in three mouse models of genitourinary cancers. First, human 786.0 renal cell carcinoma (RCC) xenograft-bearing female nude mice were treated p.o., q.d. with vehicle, axitinib (30 mg/kg), X4P-001 (100 mg/kg), EMU-116 (3, 10, or 30 mg/kg), X4P + axitinib, or EMU-116 + axitinib. Subcutaneous tumor volume was monitored using calipers. Second, nude male mice bearing intratibial, luciferase-expressing human PC-3 prostate cancer xenografts were treated with vehicle (p.o., q.d.), docetaxel (10 mg/kg i.p. weekly), X4P-001 (10 or 30 mg/kg p.o., q.d.), EMU-116 (10 or 30 mg/kg p.o., q.d.), X4P + axitinib, or EMU + axitinib. Intratibial tumor volume was monitored via luminescence imaging. Third, syngeneic RENCA RCC tumor-bearing female Balb/c mice were treated p.o., q.d. with vehicle, X4P-001 (30 mg/kg), or EMU-116 (30 mg/kg). Subcutaneous tumor volume was monitored using calipers, and immune cell subsets in bone marrow, blood, tumor, and tumor-draining lymph nodes were quantified via flow cytometry. Results: In the RCC xenograft model in combination with axitinib, EMU-116 (3 or 10 mg/kg) was equally effective at decreasing tumor burden compared to X4P-001 (100 mg/kg), whereas EMU-116 (30 mg/kg) was more effective. In the bone metastatic prostate cancer xenograft model, EMU-116 was as or more effective than X4P-001 when paired with docetaxel. In the syngeneic RCC model, EMU-116 mobilized T cells more effectively than X4P-001. Conclusion: EMU-116, at the same or lower dose, was more efficacious than X4P-001 in these models. These results highlight EMU-116 as a clinical candidate with significant therapeutic potential to synergize with chemotherapeutics, targeted therapies, and immuno-oncology agents. Citation Format: Eric J. Miller, Carrie Q. Sun, Petra Gregorova, Edgars Jecs, Yesim Altas Tahirovic, Robert J. Wilson, Huy H. Nguyen, Savita K. Sharma, Perry Bartsch, Zachary Sticher, Levi Moellering, Priscilla Davidson, Ryan Jajosky, Michael D'Erasmo, Manohar Saindane, Zafer Sahin, Nicholas S. Akins, Alexander A. Kolykhalov, Lawrence Wilson, Rebecca S. Arnold, John A. Petros, Haydn Kissick, Lingjie Xu, Yi Jiang, Dennis C. Liotta. Orally bioavailable small molecule CXCR4 antagonists with enhanced efficacy in mouse models of genitourinary cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2649.

The Role of CD4+CD8+ T Cells in HIV Infection With Tuberculosis

BackgroundTuberculosis (TB) is an important opportunistic infection in acquired immunodeficiency diseases (AIDS). Although the frequency of CD4+CD8+ double-positive (DP) T cells has been observed to increase in pathological conditions, their role (phenotypic and functional) is poorly described, especially in human immunodeficiency virus (HIV) infection with TB (HIV/TB (HT) coinfection).MethodsThe percentage and phenotypic and functional properties of peripheral blood DP T cells in patients with HT coinfection in comparison to uninfected controls and to patients with HIV or TB mono-infection were analyzed by direct intracellular cytokine staining (ICS).ResultsTotal and CD4lowCD8high DP T cells were significantly increased in patients with both HIV and TB mono-infection, especially in patients with HT coinfection. Compared with healthy controls (HCs), the percentage of DP T cells expressing chemokine receptor 5 (CCR5) in patients with HT coinfection was significantly higher. Compared with HCs and patients with TB, a lower percentage of tumor necrosis factor α (TNF-α) secreting DP T cells and a higher percentage of granzyme A-secreting DP T cells were observed in patients with HIV mono-infection and HT coinfection, respectively. In addition, DP T cells expressed more cytolytic markers (granzyme A and perforin) than CD4+ T cells, but similarly to CD8+ T cells in patients with HT coinfection.ConclusionsOur data suggested that HT coinfection resulted in a marked increase in DP T cells, especially the CD4lowCD8high subpopulation. DP T cells may be susceptible to HT coinfection, and have the same cytotoxic function as CD8+ T cells.

Multi-functional HCV-specific CD4+ T cells associated with viral control during the postpartum period express Th1- and Tfh-biasing transcription factors

Abstract Chronic hepatitis C virus (HCV) infection is characterized by dysfunctional HCV-specific CD8+ T cells, rare CD4+ T responses, and stable high-level viremia. Recovered CD4+ T cell function and unusual declines in viremia have been observed in some women after childbirth. Whether recovered CD4+ T cells are of lineages to help B cells or CD8 T cells is unknown. Preliminary studies suggest both may be true. In 7 women with postpartum viral suppression (>= 1 log10 by 3 months postpartum, “controllers”), and 7 women with more stable viral levels, “non-controllers”, circulating HCV-tetramer+ (tet+) CD4+ T cells expressed chemokine receptors associated with two predominate populations, Th1-biased Tfh (cTfh1) cells and Th1 cells – with a higher cTfh1/Th1 ratio linked to viral control. Here we assessed HCV-specific cTfh1 and Th1 functional responses by combined surface chemokine receptor and intracellular cytokine staining (ICS) after HCV peptide stimulation, and we also assessed expression of lineage-defining transcription factors on HCV-tet+ cells. HCV-specific cytokine+ cells were predominantly cTfh1 or Th1 populations, and multi-functionality correlated with viral control. HCV-tet+ CD4+ T cell Tbet and BCL6 expression levels did not differ by degree of viral control, but both were enhanced in tet+cTfh1 cells relative to bulk cTfh1 cells, and tet+ Th1 cells expressed significantly more BCL6 than bulk Th1 cells. Together, these data point to a postpartum CD4+ T cell recovery driven by transcription factors favoring cTfh1/Th1-biased phenotypes. Understanding how these cells interact with CD8+ T cells and B cell will be vital for understanding this unique instance of natural control of a chronic viral infection. Supported by a grant from the NIH (R01 AI096882).

The Application of ‘Drug-Reversible’ CAR-T Cells Directed Against Recipient Hematopoietic Cells As a Selective Conditioning Strategy for Stem Cell Transplantation

The transplant of autologous or allogeneic hematopoietic stem cells (HSCs) has the proven ability to treat a wide array of malignant and non-malignant hematological diseases. The preparative regimen, however, routinely entails aggressive and genotoxic treatment with total body irradiation and/or chemotherapy, which brings severe and even life-threatening complications that limit its broader application. Previous experimental studies have established that depletion of recipient HSCs is an essential requirement of these conditioning regimens in allowing successful engraftment of the composite donor HSCs. Animal and clinical studies have also indicated that alloreactive anti-HSC donor T cells additionally facilitate stem cell engraftment, but this is often accompanied by the risks of GvHD. This has prompted the consideration of alternative conditioning methods for the depletion of HSCs with less toxic side-effects, such as anti-c-kit and anti-CD45 antibody-directed treatments. In this way, more precise HSC targeting may also be achieved by the application of short-lived, genetically engineered chimeric antigen receptor (CAR)-T cells for stem cell transplantation conditioning.We developed a novel and controllable CAR-T approach for recipient HSC targeting via genetic modification using the non-viral piggyBac™ (PB) transposon system. As opposed to viral vector delivery systems, the relatively large carrying capacity of PB allows the stable introduction of at least three separate genes encoded within the same tri-cistronic transgene cassette. This includes a second-generation CAR that targets either human c-kit (CD117) or prominin-1 (CD133), markers known to be antigenically expressed on the surface of HSCs. In addition, a drug resistance element serves as a selection gene that, in combination with a non-genotoxic drug, provides an effective method of CAR-T cell purification during manufacture. Importantly, a small molecule drug-inducible safety switch gene is also included to facilitate rapid in vivo clearance of the CAR-T cells after depletion of recipient HSCs and prior to donor HSC transplant. Lastly, as a result of the manufacturing process, the majority of the CAR-T cells express chemokine receptors such as CXCR4 that can allow more selective trafficking to the bone marrow (BM) for eradication of resident HSCs.To select a lead candidate from a panel of anti-HSC CAR constructs, CD3/CD28 stimulated T cells from human peripheral blood were first electroporated with mRNA encoding each of the CAR candidates directed against either c-kit or CD133. CAR surface expression was confirmed in transfected T cells by flow cytometry. In vitro functional assays were performed by co-culturing mRNA-transfected CAR-T cells with mouse or human cell lines (EML-C1, TF-1 and K562), expressing either c-kit or CD133, as well as mouse and human primary BM cells. Lead CAR candidates were identified from their specific activation of the CAR-T cells through degranulation according to CD107a expression and secretion of IFNγ. Furthermore, those CARs were also capable of selectively depleting c-kit or CD133 positive cells. Interestingly, some mRNA-transfected CAR-T cells retained effector activity against target c-kit+ TF-1 cells even in the presence of its soluble ligand, stem cell factor. Next, lead CAR candidates were co-expressed with the selection and drug-inducible safety switch genes in the same tri-cistronic transgene and then stably delivered to T cells using PB. The manufacturing process yielded CAR-T cells that were mainly of the T memory stem cell (Tscm) phenotype, as determined by positive expression of CD62L and CD45RA, and also expressed high levels of the CXCR4 chemokine receptor. Similar to the mRNA-transfected CAR-T cells, these stably-transposed cells were capable of extensive effector capabilities including specific depletion of c-kit or CD133 expressing target cells.Future studies will evaluate PB-produced lead anti-HSC CAR-T cells in immune-deficient NSG mice with pre-established xenogeneic human hematopoietic chimerism, along with standard busulfan or radiation conditioning controls. This approach constitutes a novel targeted biological therapy that is envisaged to lead the way towards minimally toxic transplant regimens for depletion of endogenous HSCs in the BM and to procure their replacement with engrafted allogeneic or gene-corrected stem cells. DisclosuresTimberlake:Poseida Therapeutics, Inc.: Employment. Richter:Poseida Therapeutics, Inc.: Employment. Wang:Poseida Therapeutics, Inc.: Employment. Cam:Poseida Therapeutics, Inc.: Employment. Tan:Poseida Therapeutics, Inc.: Employment. Ostertag:Poseida Therapeutics, Inc.: Employment, Equity Ownership. Shedlock:Poseida Therapeutics, Inc.: Employment. Down:Poseida Therapeutics, Inc.: Employment.

Innate-like Chemokine Receptor Profile and Migratory Behaviour By Terminally Differentiated and Educated NK Cells

Natural Killer (NK) cells play an essential role in cancer surveillance and have a unique capability of spontaneous cytotoxicity against cancer cells. The human NK cell repertoire is functionally diversified through a tightly regulated differentiation process characterized by an early transition from CD56bright to CD56dim NK cells, followed by coordinated changes in expression of inhibitory receptors, including NKG2A and killer cell immunoglobulin-like receptors (KIR). The acquisition of self HLA class I binding KIRs during NK cell differentiation tunes the cytotoxic potential of NK cells in a process termed education, characterized by increased loading of granzyme B in dense core granules. Although NK cell differentiation and education are critical determinants of the functional potential of the cell, little is known about how these events shape the migratory behavior of NK cells. To mediate appropriate and directed immune response against cancer, NK cells must be capable of migration to the tumor site. This process is mediated by chemokines, which guide cell migration by binding to their specific receptors. For example, in multiple myeloma, CXCR3 and CCR5 ligands (MIG, IP-10, and MIP-1a) are significantly upregulated in the bone marrow compared to healthy controls, affecting the composition of immune cells in the tumor microenvironment. In order to delineate the homing patterns of distinct NK cell subsets, we used high-dimensional flow cytometry combined with functional assays to map the NK cell chemokine receptor expression and migratory behavior. We screened resting and cytokine/feeder cell stimulated peripheral blood NK cells for the expression of a panel of 20 chemokine receptors (A). Based on CD56, CD57, NKG2A, and KIR expression, NK cells were divided into 6 phenotypically and functionally distinct subsets that were ordered according to their differentiation status (B). We found that the expression of CX3CR1, CXCR1, CXCR2, and CMKLR1 gradually increased during differentiation, whereas the expression of CXCR3, CCR7, and CCR5 was lower in more differentiated NK cells. CXCR4, CCR4, and CCR2 expression was relatively uniform across all subsets. Interestingly, CCR1 and CXCR6 were expressed mainly on less differentiated NKG2A+ CD56dim NK cells (B). Next, we stratified the chemokine receptor expression on mature KIR+ NK cells based on the expression of self (educated) or non-self KIR (uneducated). Educated NK cells expressed CXCR1, CX3CR1, CCR5, and CMKLR1 at higher levels than the uneducated NK cells. Conversely, CXCR3 was expressed at lower levels on educated NK cells (C). No difference was observed for CXCR2 expression. To determine whether the observed differences in chemokine receptor expression translate into altered chemokine responsiveness between the subsets, we combined the transwell system with multicolor flow cytometry. We found that the chemokine-induced migration capability of NK cells correlated closely with the expression level of corresponding chemokine receptor, leading to subset specific responses to various chemokine gradients (D). The present results show that peripheral blood NK cell chemokine receptor profile changes in a coordinated fashion during NK cell differentiation and is further influenced by the expression of self-specific KIR. Interestingly, receptors which expression declines during NK cell differentiation (CCR5, CCR7, and CXCR3) are commonly associated with adaptive T cell responses to viruses, whereas receptors that are upregulated along the differentiation axis (CXCR1, CXCR2, CX3CR1, CMKLR1) are typical for neutrophils and macrophages as a part of the innate immune response. Thus, our results suggest that NK cell differentiation and education processes together shape the NK cell migratory capabilities to promote homing of the most functional NK cell subsets to the site of inflammation and serve as the first line of defense in the immune response to pathogens and tumors. Figure Disclosures Malmberg: Fate Therapeutics: Consultancy, Patents & Royalties; Vycellix: Membership on an entity's Board of Directors or advisory committees.

Early response marker during pembrolizumab treatment in metastatic urothelial cancer: Temporal shift in peripheral CD4 T cells expressing chemokine receptors.

5033 Background: Approval of PD1 blockade greatly improved treatment possibilities for patients with platinum-resistant metastatic urothelial cancer (mUC), however the current response rate for pembrolizumab is less than 25%. Since PD-L1 expression does not have predictive value in this setting, the aim of this study was to identify new markers to improve patient selection. Methods: Between Sept 2017 and Jan 2020, 84 mUC patients received pembrolizumab in a prospective biomarker discovery study (NCT03263039). Peripheral blood samples (n = 22) taken prior to and at 6 and 12 weeks after start of treatment were analyzed for frequencies of CD4 and CD8 T cells expressing co-inhibitory, co-stimulatory and chemokine receptors using multiplex flow cytometry. Plasma chemokine levels were determined using ELISA (n = 38), and fresh tumor biopsies obtained prior to and during treatment (n = 26) were analyzed for densities and phenotypes of T cells using multiplex immunofluorescence staining. T cell receptor clonality was analyzed in peripheral blood (n = 10) and tumor biopsies (n = 6) using RNA sequencing. Patients were classified as responder (complete or partial response) or non-responder (progressive disease) according to RECIST v1.1 after 12 weeks of treatment. Results: Longitudinal sampling revealed that upon treatment the frequency of CXCR3+ CD4 T cells decreased in responders, whereas the frequency of CXCR3+ CCR1+ CD4 T cells drastically increased in non-responders. Before treatment, the frequency of CD4 T cells co-expressing CXCR3 and CCR1 was already decreased in responders. Notably, in responders, the treatment-related decrease in frequency of CD4 T cells expressing chemokine receptors was accompanied by a decrease in the frequency of CD4 T cells expressing the co-inhibitory receptor PD1, whereas an increase in the frequency of CD4 T cells expressing the co-stimulatory receptor 4-1BB was observed. These findings will be complemented with chemokine levels in plasma, contexture of T cells in tumor biopsies, and T cell receptor clonality analysis. Conclusions: mUC patients responding to pembrolizumab treatment demonstrated an on-treatment decrease in frequency of CD4 T cells expressing chemokine receptors that is accompanied by a changed frequency of co-signaling receptor expressing CD4 T cells. These data show that dynamic immune phenotyping can distinguish effective from less effective immune activation by pembrolizumab, and may provide early markers for benefit from PD1 blockade in mUC patients.

CD4+ T Cells in the Blood of MS Patients Respond to Predicted Epitopes From B cell Receptors Found in Spinal Fluid.

B cells are important pathogenic players in multiple sclerosis (MS), but their exact role is not known. We have previously demonstrated that B cells from cerebrospinal fluid (CSF) of MS patients can activate T cells that specifically recognize antigenic determinants (idiotopes) from their B cell receptors (BCRs). The aim of this study was to evaluate whether in silico prediction models could identify antigenic idiotopes of immunoglobulin heavy-chain variable (IGHV) transcriptomes in MS patients. We utilized a previously assembled dataset of CSF IGHV repertoires from MS patients. To guide selection of potential antigenic idiotopes, we used in silico predicted HLA-DR affinity, endosomal processing, as well as transcript frequency from nine MS patients. Idiotopes with predicted low affinity and low likelihood of cathepsins cleavage were inert controls. Peripheral blood mononuclear cells from these patients were stimulated with the selected idiotope peptides in presence of anti-CD40 for 12 h. T cells were then labeled for activation status with anti-CD154 antibodies and CD3+CD4+ T cells phenotyped as memory (CD45RO+) or naïve (CD45RO−), with potential for brain migration (CXCR3 and/or CCR6 expression). Anti-CD14 and -CD8 were utilized to exclude monocytes and CD8+ T cells. Unstimulated cells or insulin peptides were negative controls, and EBNA-1 peptides or CD3/CD28 beads were positive controls. The mean proportion of responding memory CD4+ T cells from all nine MS patients was significantly higher for idiotope peptides with predicted high HLA-DR affinity and high likelihood of cathepsin cleavage, than toward predicted inert peptides. Responses were mainly observed toward peptides affiliated with the CDR3 region. Activated memory CD4+ T cells expressed the chemokine receptor CCR6, affiliated with a Th17 phenotype and allowing passage into the central nervous system (CNS). This in vitro study suggests that that antigenic properties of BCR idiotopes can be identified in silico using HLA affinity and endosomal processing predictions. It further indicates that MS patients have a memory T cell repertoire capable of recognizing frequent BCR idiotopes found in endogenous CSF, and that these T cells express chemokine receptors allowing them to reach the CSF B cells expressing these idiotopes.

Chemokine-Regulated Recruitment of Antigen-Specific T-Cell Subpopulations to the Liver in Acute and Chronic Hepatitis C Infection.

In hepatitis C virus (HCV) infection, virus-specific CD8+ T cells are recruited to the liver for antiviral activity. Multiple chemokine ligands are induced by the infection, notably interferon-inducible chemokine, CXCL10. In HCV, intrahepatic T cells express chemokine receptors (CCRs), including CXCR3, CXCR6, CCR1, and CCR5, but CCR expression on antigen-specific effector and memory T cells has not been investigated. Paired blood and liver samples were collected from subjects with chronic HCV for flow cytometric analysis of CCR expression on CD8+ T cells. Expression of these CCRs was then examined on HCV-specific CD8+ T-cell subpopulations in the blood from subjects with acute or chronic HCV. Relative to peripheral blood, the liver was enriched with CD8+ T cells expressing CCR2, CCR5, CXCR3, and CXCR6 either singly or in combinations. CXCR3 was preferentially expressed on HCV-specific CD8+ T cells in both acute and chronic phases of infection in blood. Both CXCR3 and CCR2 were overexpressed on HCV-specific CD8+CCR7+CD45RO+ (central memory) cells, whereas effector memory (CD8+CCR7-CD45RO+) cells expressed more CXCR6. CXCR3-mediated signals support the accumulation of HCV-specific CD8+ memory T cells in the infected liver, and emphasize the importance of the CXCL10/CXCR3 trafficking pathway during acute and chronic HCV infection.

Chemokine-mediated B cell trafficking during early rabbit GALT development.

Microbial and host cell interactions stimulate rabbit B cells to diversify the primary Ab repertoire in GALT. B cells at the base of appendix follicles begin proliferating and diversifying their V-(D)-J genes around 1 wk of age, ∼5 d after B cells first begin entering appendix follicles. To gain insight into the microbial and host cell interactions that stimulate B cells to diversify the primary Ab repertoire, we analyzed B cell trafficking within follicles during the first week of life. We visualized B cells, as well as chemokines that mediate B cell homing in lymphoid tissues, by in situ hybridization, and we examined B cell chemokine receptor expression by flow cytometry. We found that B cells were activated and began downregulating their BCRs well before a detectable B cell proliferative region appeared at the follicle base. The proliferative region was similar to germinal center dark zones, in that it exhibited elevated CXCL12 mRNA expression, and B cells that upregulated CXCR4 mRNA in response to signals acquired from selected intestinal commensals localized in this region. Our results suggest that after entering appendix follicles, B cells home sequentially to the follicle-associated epithelium, the follicular dendritic cell network, the B cell/T cell boundary, and, ultimately, the base of the follicle, where they enter a proliferative program and diversify the primary Ab repertoire.

Naïve T cells, unconventional NK and NKT cells, and highly responsive monocyte-derived macrophages characterize human cord blood

This study compares the human immune systems of neonates and adults. Flow cytometric analysis was used to study the cellular phenotypes of cord blood (CB) and adult peripheral blood (APB). Luminex analysis was used to determine the levels of cytokines in cell culture supernatants. Our findings indicate that T cells in CB were mainly naïve and thus less responsive to PMA/ionomycin with the synthesis of cytokines. The percentages of CD3+CD4+CD25high and of CD3+CD4+CD25dim cells expressing chemokine receptors were different between CB and APB. TLR1, TLR6 and TLR9 expressions on NK and NKT cells also differed between CB and APB. CB monocyte-derived macrophages responded better than APB macrophages to TLR ligands with increased secretion of inflammatory cytokines, especially IL-6. The high levels of the inflammatory cytokines in cell culture supernatants of CB were mainly due to higher numbers of responsive macrophages, since dendritic cell numbers were lower in CB than APB.

PWE-145 Characterisation Of Circulating And Liver Infiltrating Mait Cells In Human Inflammatory Liver Diseases

IntroductionMucosal-Associated Invariant T (MAIT) cells are characterised by expression of the semi-invariant TCR α-chain Vα7.2-Jα33 and high expression of CD161 and shown to play a role at mucosal barriers. They...

Metformin aggravates immune-mediated liver injury in mice.

Hepatotoxicity of the antidiabetic drug metformin has been reported, but the underlying mechanisms remain unclear. We here investigated the effect of metformin in immune-mediated liver damage. While not hepatotoxic alone, metformin (200mg/kg) aggravated concanavalin A (Con A, 12mg/kg)-induced hepatitis, an experimental model of T cell-mediated liver injury, in both relatively resistant BALB/c and highly susceptible C57Bl/6 mice. Metformin+Con A-treated mice had elevated serum levels of pro-inflammatory cytokines TNF-α and IFN-γ, accompanied by a massive mononuclear cell infiltration in the liver. This was associated with the higher numbers of CD4(+) T cells producing TNF-α, IFN-γ and IL-17, CD4(+) T cells expressing chemokine receptor CXCR3 and activation marker CD27, CD4(+)CD62L(-)CCR7(-) and CD8(+)CD62L(-)CCR7(-) effector memory cells, IFN-γ producing NK cells, IL-4 and IL-17 producing NKT cells and IL-12 producing macrophages/dendritic cells. The percentage of CD4(+)CXCR3(+)Tbet(+)IL-10(+) and CD4(+)CD69(+)CD25(-) regulatory T cells was reduced. Metformin stimulated inducible nitric oxide synthase (iNOS) expression in the liver and spleen, and genetic deletion of iNOS attenuated the hepatotoxicity of metformin. Metformin increased the autophagic light chain 3 conversion and mRNA expression of important autophagy-inducing (beclin-1, Atg5 and GABARAP) and pro-apoptotic (p21, p27, Puma, Noxa, Bax, Bad, Bak1, Bim and Apaf1), but not anti-apoptotic molecules (Bcl-xL, survivin and XIAP), which correlated with the apoptotic caspase-3/PARP cleavage in the liver. The autophagy inhibitor chloroquine (20mg/kg) prevented liver injury and apoptotic changes induced by metformin. Therefore, metformin aggravates immune-mediated hepatitis by promoting autophagy and activation of immune cells, affecting effector, as well as liver-specific regulatory T cells and iNOS expression.

Characteristics of differentiated CD8+ and CD4+ T cells present in the human brain

Immune surveillance of the central nervous system (CNS) by T cells is important to keep CNS-trophic viruses in a latent state, yet our knowledge of the characteristics of CNS-populating T cells is incomplete. We performed a comprehensive, multi-color flow-cytometric analysis of isolated T cells from paired corpus callosum (CC) and peripheral blood (PB) samples of 20 brain donors. Compared to PB, CC T cells, which were mostly located in the perivascular space and sporadically in the parenchyma, were enriched for cells expressing CD8. Both CD4(+) and CD8(+) T cells in the CC had a late-differentiated phenotype, as indicated by lack of expression of CD27 and CD28. The CC contained high numbers of T cells expressing chemokine receptor CX3CR1 and CXCR3 that allow for homing to inflamed endothelium and tissue, but hardly cells expressing the lymph node-homing receptor CCR7. Despite the late-differentiated phenotype, CC T cells had high expression of the IL-7 receptor α-chain CD127 and did not contain the neurotoxic cytolytic enzymes perforin, granzyme A, and granzyme B. We postulate that CNS T cells make up a population of tissue-adapted differentiated cells, which use CX3CR1 and CXCR3 to home into the perivascular space, use IL-7 for maintenance, and lack immediate cytolytic activity, thereby preventing immunopathology in response to low or non-specific stimuli. The presence of these cells in this tightly regulated environment likely enables a fast response to local threats. Our results will enable future detailed exploration of T-cell subsets in the brain involved in neurological diseases.

CCR3, CCR4, CCR5, and CXCR3 expression in peripheral blood CD4+ lymphocytes in gastric cancer patients

Background:CD4+(TH1, and TH2) cell groups in the point of view of chemokine receptor expression were considered in blood of stomach cancer patients.Materials and Methods:The percentage of blood CD4+ T cells expressing chemokine receptors (before and after gastrectomy) was determined by flow cytometry (Becton Dickinson, USA) using the following chemokine receptor antibodies: anti-CCR5, anti-CXCR3, anti-CCR3 and anti-CCR4.Results:The means of CD4+ CCR5+ expressing cells was 1.23% ± 0.90, 0.83% ± 0.34 and 1.34% ± 0.74 in control, pre- and post-operation groups, respectively. CD4+ CXCR3+ expressing cells were 19.09% ± 8.4, 16.95% ± 5.71 and 25.08% ± 9.31, respectively. Similar pattern was seen for CD4+ CCR3+ and CD4+ CCR4+ expressing cells. Pearson correlation analysis shows no relationship between CCR3 and CCR4 expressions on TCD4 cells (r = 0.211, P = 0.126). The complex expression TH1 (CD4+ CXCR3+ CCR5+) receptors determined 1.14% ± 0.54 for control group, 0.86% ± 0.49 for pre-T and 1.57% ± 0.67 for post-T group. Moreover, the TH2 (CD4+ CCR3+ CCR4+) expression was 1.60% ± 1.05 for control group, 1.57% ± 0.83 for pre-T and 1.27% ± 0.66 for post-treatment group. Pearson correlation analysis shows that only the CCR3 and CCR5 expression was statistically correlated (r = 0.321, P = 0.018).Conclusion:Due to low expression of CCR5 in TH1 and CCR3 in TH2 cells, it seems that utility of these is extremely limited for clinical evaluation, but not scientific purpose. Moreover, considering the CXCR3 for TH1 cells and CCR4 expression for TH2 cells, due to considerable expression, may be practical.

Comparing the safety and immunogenicity of a candidate TB vaccine MVA85A administered by intramuscular and intradermal delivery

BackgroundNew vaccines to prevent tuberculosis are urgently needed. MVA85A is a novel viral vector TB vaccine candidate designed to boost BCG-induced immunity when delivered intradermally. To date, intramuscular delivery has not been evaluated. Skin and muscle have distinct anatomical and immunological properties which could impact upon vaccine-mediated cellular immunity. MethodsWe conducted a randomised phase I trial comparing the safety and immunogenicity of 1×108pfu MVA85A delivered intramuscularly or intradermally to 24 healthy BCG-vaccinated adults. ResultsIntramuscular and intradermal MVA85A were well tolerated. Intradermally-vaccinated subjects experienced significantly more local adverse events than intramuscularly-vaccinated subjects, with no difference in systemic adverse events. Both routes generated strong and sustained Ag85A-specific IFNγ T cell responses and induced multifunctional CD4+ T cells. The frequencies of CD4+ T cells expressing chemokine receptors CCR4, CCR6, CCR7 and CXCR3 induced by vaccination was similar between routes. ConclusionsIn this phase I trial the intramuscular delivery of MVA85A was well tolerated and induced strong, durable cellular immune responses in healthy BCG vaccinated adults, comparable to intradermal delivery. These findings are important for TB vaccine development and are of relevance to HIV, malaria, influenza and other intracellular pathogens for which T cell-inducing MVA-based vaccine platforms are being evaluated.

Impact of CCL2 and Its Receptor CCR2 Gene Polymorphism in North Indian Population: A Comparative Study in Different Ethnic Groups Worldwide

Chemokine are small, inducible pro-inflammatory cytokines involved in many biological processes, such as migration of leukocytes, atherosclerosis, angiogenesis, tumor growth, and metastasis. Chemokine are also known to influence tumor cell's activity. Specifically, tumor cells express chemokine receptors in a non random manner suggesting a role of chemokine in metastatic destination of tumor cells. The present study was conducted to determine distribution of (Chemokine receptor 2) CCR2 V64I, Chemokine ligand 2 CCL2 I/D, and CCL2 2518 A>G gene polymorphisms in North Indian population and compare with different populations globally. Polymerase chain reaction (PCR)-based analysis was conducted in 200 normal healthy individuals of similar ethnicity. Allelic frequencies in wild type (GG) of CCR2 V64I G>A were 63% G; CCL2 I/D 42% II; CCL2 2518 A>G 40.5% A. The minor variant allele frequency in our population was as follows: 19.5% for CCR2 V64I, 35.5% for CCL2 I/D, 35.3% for CCL2 2518 A>G. We further compared frequency distribution for these genes with various published studies in different ethnicity. Our results suggested that frequency in chemokine genes exhibit distinctive pattern in India that could be attributed to ethnicity variation. This could assist in high-risk screening of human exposed to environmental carcinogens and cancer predisposition in different ethnic groups. Thus, they signify an impact of ethnicity and provide a basis for future epidemiological and clinical studies.

Deletion of IL-33R (ST2) Abrogates Resistance to EAE in BALB/C Mice by Enhancing Polarization of APC to Inflammatory Phenotype

The administration of interleukin 33 and deletion of IL-33 receptor, ST2 molecule, affects the induction of autoimmunity in different experimental models of human autoimmune diseases. The aim of this study was to analyze the effect of ST2 deletion on the induction of experimental autoimmune encephalomyelitis (EAE) in resistant BALB/c mice. Mice were immunized with MOG35–55 peptide or disease was induced by passive transfer of encephalitogenic singenic cells and EAE was clinically and histologically evaluated. Expression of intracellular inflammatory cytokines, markers of activation and chemokine receptors on lymphoid tissue and CNS infiltrating mononuclear cells was analyzed by flow cytometry. We report here that deletion of ST2−/− molecule abrogates resistance of BALB/c mice to EAE induction based on clinical and histopathological findings. Brain and spinal cord infiltrates of ST2−/− mice had significantly higher number of CD4+ T lymphocytes containing inflammatory cytokines compared to BALB/c WT mice. Adoptive transfer of ST2−/− primed lymphocytes induced clinical signs of the disease in ST2−/− as well as in WT mice. MOG35–55 restimulated ST2−/− CD4+ cells as well as ex vivo analyzed lymph node cells had higher expression of T-bet and IL-17, IFN-γ, TNF-α and GM-CSF in comparison with WT CD4+ cells. ST2−/− mice had higher percentages of CD4+ cells expressing chemokine receptors important for migration to CNS in comparison with WT CD4+ cells. Draining lymph nodes of ST2−/− mice contained higher percentage of CD11c+CD11b+CD8− cells containing inflammatory cytokines IL-6 and IL-12 with higher expression of activation markers. Transfer of ST2−/− but not WT dendritic cells induced EAE in MOG35–55 immunized WT mice. Our results indicate that ST2 deficiency attenuates inherent resistance of BALB/c mice to EAE induction by enhancing differentiation of proinflammatory antigen presenting cells and consecutive differentiation of encephalitogenic T cells in the draining lymph node rather than affecting their action in the target tissue.

Maternal Micronutrient Supplementation Suppresses T Cell Chemokine Receptor Expression and Function in F1 Mice1–3

Prenatal environmental exposures play a critical role in determining late-life chronic disease susceptibility. However, the mechanisms linking the in utero environment and disease development in the offspring are poorly understood. Recent investigations have confirmed a central pathogenic role of T cell chemokine receptors, particularly C-C chemokine receptor (CCR) 2 and CCR5, in chronic inflammatory conditions. This study was designed to determine the effect of a synthetic prenatal micronutrient supplementation (MS) diet rich in methionine pathway metabolites on the T cell chemokine system in F1 C57Bl/6 mice. Female mice were fed either an MS or control diet 3 wk prior to mating, during pregnancy, and lactation. At 4 wk of age, F1 mice were killed for experiments or were fed the standard NIH-31 diet and allowed to age. Food consumption, maternal weight gain, and litter size were similar in dams fed the control and MS diets. However, the F1 offspring of dams fed the MS diet were smaller in size (P< 0.001). T cells from the MS F1 offspring had global hypermethylation compared with control F1 offspring (P< 0.005), corresponding to lower T cell chemokine receptor expression [CCR2 (P< 0.001), CCR5 (P< 0.001), and C-x-C chemokine receptor 3 (P< 0.01)] and cytokine expression [TNFa (P< 0.05), IL-2 (P< 0.001), and IL-4 (P< 0.01)]. Reduced T cell chemokine receptor gene expression in MS F1 mice was associated with decreased chemotaxis in vitro to C-C chemokine ligand (CCL) 2 and C-X-C chemokine ligand 10 (P< 0.01) and in vivo to CCL2 (P< 0.01). Taken together, the results suggest that epigenetic alteration through prenatal diet manipulation reduces the response to proinflammatory signals in mice.