Up-regulation Of CCR4 Research Articles

CCL17 and CCL22 chemokines are upregulated in human obesity and play a role in vascular dysfunction.

Chemokines are known to play critical roles mediating inflammation in many pathophysiological processes. The aim of this study was to investigate the role of chemokine receptor CCR4 and its ligands CCL17 and CCL22 in human morbid obesity. Circulating levels of CCL17 and CCL22 were measured in 60 morbidly obese patients (mean age, 45 ± 1 years; body mass index/BMI, 44 ± 1 kg/m2) who had undergone bariatric bypass surgery, and 20 control subjects. Paired subcutaneous (SCAT) and visceral adipose tissue (VCAT) from patients were analysed to measure expression of CCR4 and its ligands by RT-PCR, western blot and immunohistochemical analysis. The effects of CCR4 neutralization ex vivo on leukocyte-endothelial cells were also evaluated. Compared with controls, morbidly obese patients presented higher circulating levels of CCL17 (p=0.029) and CCL22 (p<0.001) and this increase was positively correlated with BMI (p=0.013 and p=0.0016), and HOMA-IR Index (p=0.042 and p< 0.001). Upregulation of CCR4, CCL17 and CCL22 expression was detected in VCAT in comparison with SCAT (p<0.05). Using the parallel-plate flow chamber model, blockade of endothelial CCR4 function with the neutralizing antibody anti-CCR4 in morbidly obese patients significantly reduced leucocyte adhesiveness to dysfunctional endothelium, a key event in atherogenesis. Additionally, CCL17 and CCL22 increased activation of the ERK1/2 mitogen-activated protein kinase signalling pathway in human aortic endothelial cells, which was significantly reduced by CCR4 inhibition (p=0.016 and p<0.05). Based on these findings, pharmacological modulation of the CCR4 axis could represent a new therapeutic approach to prevent adipose tissue dysfunction in obesity.

Aryl Hydrocarbon Receptor Deficient Donor T Cells Display Decreased Migration and Cause Reduced Or Enhanced Graft-Versus-Host Diseases In Different Transplant Models

The transcription factor aryl hydrocarbon receptor (AhR) is a cytosolic sensor of numerous small synthetic compounds (xenobiotics) and natural chemicals. Ligand binding of AhR causes a conformational change of the receptor, allowing its translocation to nucleus to regulate an array of genes. Different ligands could induce different sets of genes. AhR was first discovered as the mediator of dioxin toxicity. Its role in immunity was recently extensively investigated and expanded exponentially. Here we investigated the role of AhR in donor T cell-induced graft-versus-host diseases (GvHD) after bone marrow transplant in two MHC-mismatched models. B6D2 or Balb/c recipients were irradiated with one dose (950 rads for B6D2 and 800 rads for Balb/c) one day before transplant. C57BL/6 WT or AhR deficient (AhR KO) T cells were transplanted with T cell-depleted bone marrow to B6D2 or Balb/c, at a dose of three million T cells or five hundred thousand T cells, respectively. At different time points, recipient lymphoid organs or target organs were harvested and used for flow analysis or ELISA. A group of recipient mice were observed for an extended time to establish GvHD scores and survival curves. In B6 to B6D2 model, recipient mice transplanted with AhR KO T cells displayed lower GvHD scores and survived longer than mice transplanted with WT T cells (Figure 1C). We found that AhR KO donor T cells failed to accumulate in lymph nodes and spleen as rapidly as WT T cells as evident on day 1 and day 3 post-transplant (Figure 1A). Further investigation showed that the proliferation and cell death were similar between WT and AhR donor T cells, suggesting decreased migration of AhR KO T cells to lymphoid organs. It has been shown that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced AhR activation leads to the up-regulation of CCR4 and CCR5 in T cells, supporting our data that AhR affects cell migration. We also observed that lower percentage of AhR KO T cells produced IFN-g and IL-17 in lymph nodes and spleen early after transplant, but the differences disappeared at later time points (day 7). Colonic homogenates of AhR KO transplants contained less IFN-g, TNF-a, and IL-1a than WT transplants, which indicated that AhR KO T cells caused less inflammation in the gut (Figure 1B). Gut-associated injury due to inflammation is the major cause of death in this model. However, in B6 to Balb/c model, recipient mice transplanted with AhR KO T cells displayed the opposite survival curve. They had diminished survival compared to mice receiving WT T cells with most mice succumbing to GvHD around day 10 to day 15 before the onset of diarrhea. AhR KO T cells in this model still accumulated less in lymph nodes at early time points, which suggested that AhR played a role in cell migration in both models. It was noteworthy that after day 6, the number of AhR KO T cells in the spleen was actually similar to or higher than WT T cells in both models, suggesting cell proliferation was not affected by AhR deficiency. In conclusion, AhR KO T cells demonstrate decreased migration to lymphoid organs after bone marrow transplant compared to WT T cells. This decrease in migration may be the reason why mice transplanted with AhR KO T cells exhibit less inflammation in the gut and subsequently survive better from GvHD in the B6 to B6D2 model. However, mice transplanted with AhR KO T cells have diminished survival in B6 to Balb/c model despite of lower T cell numbers in lymph nodes at early time points. Thus, certain function of AhR in donor T cells is model dependent while other function is conserved among different models. These data suggest that investigators should be cautious regarding the supplementation of AhR ligands to diminish GvHD in clinical studies. Disclosures: No relevant conflicts of interest to declare.

Abstract 752: A CCR4 antagonist combined with protein-or DNA-based vaccines efficiently breaks tolerance and elicits CD8+T cells directed against self and viral associated tumor antigens

Abstract Regulatory T cells (Treg) may impede vaccine efficacy in cancer. CCR4 antagonists, an emergent class of Treg inhibitor, have been shown to block recruitment of Treg into lymph node mediated by CCL17 and CCL22. As most tumor antigens are self antigens possibly controled by Treg, our aim was to demonstrate the ability of a CCR4 antagonist to induce CD8+T cells directed against various self tumor antigens. For this purpose we selected various transgenic mice expressing Her2/neu, E7 or OVA as self antigen. Protein based vaccine vectorized or not by the B subunit of Shiga toxin (a vector targeting dendritic cells) and a DNA based vaccine coding for the E7 protein derived from HPV were included in this study and tested in combination or not with the CCR4 antagonist. Induction of functional anti-self CD8+T cells could be observed against various model self antigens (Her2/neu, E7, OVA) only when protein (delivered via the B subunit of Shiga toxin) – or DNA-based vaccines were combined with the CCR4 antagonist. Antigen specific CD8+T cells were detected by Tetramer and Elispot assays. This strategy to block Treg was more efficient than cyclophosphamide and similar to the depletion of Treg by anti-CD25 mAb.However compared to mAb, the CCR4 antagonist has a short life time which may avoid potential autoimmune complication caused by long term blockade of Treg. In contrast to anti-CD25mAb and cyclophosphamide, the CCR4 antagonist did not modify the number or the percent of peripheral Treg. As only 20% of Treg in mice expressed CCR4, we further characterized this population and showed that it corresponded to memory (CC44high) activated (ICOS+) cells. Activation of CCR4 negative Treg led to upregulation of CCR4 on these cells. Since the targeting of only 20% of Treg expressing CCR4 was sufficient to break tolerance mediated by Treg, these results strongly suggest that these CCR4+Tregs represent an important population to be targeted to modulate T reg activity. In human, we showed that CCR4 is expressed by more than 70% of peripheral or intra-lymph node Treg. The previous demonstration that a CCR4 antagonist is efficient to block human Treg, together with the high expression of CCR4 in human Treg also provide some rationale to develop this new class of Treg inhibitor in human.Our vaccine combining an efficient antigen delivery system which targets dendritic cells (the B subunit of Shiga toxin) to a CCR4 antagonist able to break tolerance mediated by Treg during the priming phase may thus represent a prototype cancer vaccine to elicit potent functional anti-tumor CD8+T cells in the context of immunosuppression mediated by Treg in cancer patients Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 752. doi:10.1158/1538-7445.AM2011-752

Upregulation of the Chemokine Receptor CCR4 in Cutaneous T-Cell Lymphoma and Nodal T-Cell Lymphoma: Implications for Targeted Therapy.

The chemokine receptor CCR4 is expressed by a minor population of non-neoplastic T-cells, particularly Th2 helper T-cells, skin-homing T-cells and CD4+CD8− thymocytes. To assess the suitability of this receptor as a target for immunotherapy, we compared expression of CCR4 in a large series of T-cell malignancies with non-neoplastic T-cells by immunohistochemistry on formalin-fixed, paraffin-embedded material. Using tissue arrays and whole tissue sections, we assessed CCR4 levels in 233 biopsy samples from 182 patients with various T-cell tumors, particularly mycosis fungoides (MF, n = 54) and Sezary syndrome (SS, n = 15). We utilized the anti-CCR4 antibody KM2160 (Kyowa Hakko Kogyo, Tokyo, Japan), whose specificity has been established by immunoprecipitation and flow cytometry on CCR4-expressing transfectants and T-cell lines. Immunostaining was graded on a 4-tier scale (negative, focal, partial and uniform positivity) and compared with staining for markers of tumor progression including CD25, CD30 and the cytotoxic marker granzyme B and with a mediator of lymphocyte homing to skin, cutaneous lymphocyte antigen (CLA). Overall, CCR4 was expressed either partially or uniformly in 49% of T-cell tumors. Among MF/SS cases, partial or uniform CCR4 expression was found in 52% of cases, including in both early patch/plaque stage lesions and disseminated disease. CCR4 was upregulated upon large cell transformation in 39% of 23 MF/SS cases studied in sequential biopsies. There was an 80% concordance rate in CCR4 staining patterns in tumor cells in biopsies taken simultaneously from different anatomic sites. Upregulation of CCR4 upon large cell transformation was independent of other markers of progression, including CD25, CD30 and granzyme B but was significantly correlated with the degree of CLA expression. In contrast to the strong intensity of CCR4 staining in MF/SS cases, dimmer more variable expression was seen in skin homing T-cells in 94% of chronic dermatitis cases (n = 18). Among other T-cell tumors, CCR4 expression was common in AIL (70%), ALCL (53%) and PTCL unspecified (55%) and in the more mature subset of precursor-T lymphoblastic lymphoma/leukemia. CCR4-expressing T-cells were rare in 12 lymph node biopsies with reactive lymphadenitis. In conclusion, the chemokine receptor CCR4 is stably upregulated in cutaneous lymphoma and nodal T-cell lymphoma as compared to levels seen in non-neoplastic T-cells and thus represents a promising antigen for selective targeting of T-cell malignancies by immunotherapy.

Expression of chemokine receptors on CD4+ T cells in peripheral blood from HIV-infected individuals in Uganda.

CXCR4, a coreceptor for T cell (T)-tropic HIV-1, is preferentially expressed on naive T cells, whereas CCR5, a coreceptor for macrophage (M)-tropic HIV-1, is preferentially expressed on previously activated memory T cells and the Th1 subset of CD4+ T cells. CCR4 is preferentially expressed on the Th2 subset of CD4+ T cells. A cross-sectional flow cytometry study was conducted to evaluate the expression of CXCR4, CCR5, and CCR4 on the peripheral blood CD4+ T cells from African HIV-1-infected and uninfected Ugandan adults. The plasma viral load in HIV-1-infected individuals was also examined. Upregulation of CCR4 and CCR5 expression but no decrease in CXCR4 expression on CD4+ T cells were obtained in peripheral blood from African adults with progression of the disease. Plasma HIV-1 viremia significantly and inversely correlated with the peripheral CD4+ T cell count but did not correlate with the degree of CCR4 and CCR5 expression on the peripheral CD4+ T cells in HIV-1-infected individuals. Our present data suggest an increase in percentage of activated memory CD4+ T cells in the advanced stage of HIV-1 infection among African adults. There was no evidence of a Th1 to Th2 shift in terms of chemokine receptor expression profile with advancing disease in the peripheral blood of these subjects.