Expression and characterization of the chemokine receptor CCR2B from rhesus monkey

Species selectivity of chemokine receptor antagonists is a potential deterrent to making preclinical assessments in vivo. To determine if rhesus monkey disease models could support these assessments, we pharmacologically and functionally characterized recombinant rhesus CCR2B receptor. For these studies we obtained the CCR2B coding region by PCR from genomic rhesus DNA and expressed the receptor as stable transfectants in Chinese Hamster Ovary cells. The surface expression of recombinant rhesus CCR2B was detected by flow cytometry using a commercially available monoclonal anti-hCCR2B antibody. This antibody was used to detect rhCCR2B on monocytes in peripheral blood mononuclear cell preparations from rhesus whole blood. The recombinantly expressed CCR2B exhibited similar high affinity binding to the CCR2 chemokine ligands from rhesus and human 125I-rhMCP-1 (K(d)=433+/-14 pM) and 125I-hMCP-1 (K(d)=550+/-256 pM). In competition binding, the receptor exhibited selective high affinity binding to the monocyte chemoattractant protein (MCP) family chemokines with little affinity for most other members of the CC family of chemokines. One exception was eotaxin, a high affinity ligand for CCR3, which bound to rhesus CCR2B receptor (K(i)=1467+/-205 pM). Chemokines which exhibited binding affinity for the receptor were tested for their ability to induce intracellular calcium release. In these experiments the relative potencies of the MCP family of chemokines for rhCCR2B were similar to the observed binding affinities. In contrast, eotaxin was functionally inactive as an antagonist or agonist to this receptor. TAK-799 (N,N-dimethyl-N-[4-[[[2-(4-methylphenyl)-6,7-dihydro-5H-benzocyclohepten-8-yl]carbonyl]amino]benzyl]tetrahydro-2H-pyran-4-aminium chloride), a dual CCR2/CCR5 antagonist, demonstrated high affinity for the rhesus CCR2B in competition with 125I-hMCP-1 binding to the receptor (K(i)=0.5 nM) and also potently blocked the MCP-1 induced calcium mobilization mediated through the receptor.     

Aminoguanidine downregulates expression of cytokine-induced Fas and inducible nitric oxide synthase but not cytokine-enhanced surface antigens of rat islet cells

Autoimmune beta-cell destruction occurs directly by cell-mediated cytotoxicity or indirectly by cytokines released from infiltrating lymphocytes. Cytokines (IL-1beta/IFN-gamma) modify or induce expression of MHC antigens and ICAM-1 on beta-cells which can lead to an improved binding of T-lymphocytes to beta-cells and finally to an enhanced cell-mediated cytotoxicity. Cytokines also induce Fas-expression and inducible nitric oxide synthase (iNOS) causing generation of nitric oxide (NO) which is toxic for beta-cells. The iNOS inhibitor aminoguanidine (AG) delays diabetes onset, but does not reduce diabetes incidence. We wanted to know whether AG inhibits cytokine-induced expression of Fas, MHC antigens and ICAM-1 on beta-cells of LEW.1W and BB/OK rat islets after culture with IL-1beta/IFN-gamma. NO was completely inhibited by 5.0 mmol/L AG while 0.5 mmol/L had no inhibitory effect. AG downregulated Fas-expression on the surface of beta-cells. Cytokine-induced/enhanced expression of MHC class-II and ICAM-1 was not affected by any AG concentration. AG syngergistically increased cytokine-induced enhancement of MHC class-I antigen density. AG possibly blocks the indirect pathway of beta-cell damage in vivo due to inhibition of Fas and iNOS and improves direct cell-mediated cytotoxicity due to drastic increased MHC class-I expression. Inhibition of only one pathway of beta-cell destruction is not sufficient to prevent diabetes.     

Immunomodulatory activity of resveratrol: discrepant in vitro and in vivo immunological effects

trans-Resveratrol is a dietary polyphenolic compound present in grapes, which has been shown to exhibit strong anti-inflammatory, antioxidant, and chemopreventive activities. In this study we have compared the in vitro and in vivo effects of resveratrol on the development of various cell-mediated immune responses, including mitogen/antigen-induced T cell proliferation, induction of cytotoxic T lymphocytes (CTLs), interleukin-2 (IL-2) induced lymphokine activated killer cells, and cytokine production. We found significant suppression (>90%) of the mitogen/antigen-induced T cell proliferation and development of allo-antigen specific CTLs in vitro with resveratrol at a concentration of 25 microM. Intragastric administration of resveratrol (2 mg daily) to mice for 4 weeks showed no effect on age-related gain in body weight, peripheral blood cell counts (WBC, RBC, or platelets), or the cellularity of bone marrow or spleen. The CD4(+) and CD8(+) T cells in spleen or colony-forming units-total in the marrow also remained unaffected by treatment with resveratrol. Spleen cells, which were stimulated in vitro after being removed from mice which had been administered resveratrol for 2 or 4 weeks, showed no significant change in IL-2 or concanavalin A induced proliferation of T cells or production of IL-2 induced lymphokine activated killer cells. Further, the production of in interferon-gamma and IL-12 was not affected by administration of resveratrol, but production of tumor necrosis factor-alpha was reduced. Even when conducted entirely in vivo, treatment with resveratrol was found to only marginally reduce allo-antigen induced T cell proliferation and the generation of CTLs in the draining lymph nodes. Thus, even though resveratrol strongly inhibits T cell proliferation and production of cytolytic cells in vitro, oral administration of resveratrol for 4 weeks does not induce hematologic or hematopoietic toxicity, and only marginally reduces the T cell-mediated immune responses.     

全反式维甲酸联合干扰素-γ对人肝癌细胞株SMMC-7721抗增殖作用的研究

目的探讨全反式维甲酸(all-trans retinoic acid,ATRA)和干扰素-γ(Interferon-gamma,IFN-γ)联合作用对于人肝癌细胞株SMMC-7721的抑制作用。方法用ATRA和IFN-γ处理SMMC-7721细胞后,应用MTT法检测SMMC-7721细胞的增殖抑制率,电镜观察细胞形态的变化,流式细胞仪检测细胞凋亡,蛋白质免疫印迹法(Western blot)检测增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)的表达变化。结果ATRA作用于SMMC-7721后,抑制细胞增殖并且诱导细胞凋亡发生,和IFN-γ联合作用后,这种作用加强;SMMC-7721细胞中PCNA的表达在ATRA作用后减少,ATRA与IFN-γ联合作用后进一步减少。结论IFN-γ可以增强ATRA对于肝癌细胞的抑制及诱导细胞凋亡的作用,并且明显下调了PCNA的表达。     

放射治疗对小鼠肾癌移植瘤效应的观察

目的:观察放射治疗对BALB/c小鼠肾癌的抑瘤作用.方法:采用Annexin-Ⅴ-FITC/PI法检测不同剂量放疗后Renca细胞的凋亡率,建立BALB/c小鼠的肾癌细胞移植瘤放射治疗的模型.采用ELISA试剂盒检测小鼠脾淋巴细胞的细胞因子IL-2、IFN-γ分泌水平.结果:①在一定照射剂量范围内,Renca细胞的凋亡率随剂量的增加而升高.②放疗组小鼠移植瘤生长速度较对照组明显减慢.③放疗组小鼠脾细胞分泌IL-2及IFN-γ明显较肿瘤对照组升高.结论:放疗组小鼠肿瘤生长受到明显抑制,与放疗引发的Renca细胞凋亡和小鼠脾细胞分泌IL-2及IFN-γ能力增强有关.     

Simultaneous detection of IFN-gamma and IL-4 in lesional tissues and whole unstimulated saliva from patients with oral lichen planus

Background:  Although the roles of interferon (IFN)-gamma and interlekin (IL)-4 in oral lichen planus (OLP) have been described extensively in past decades, the available results are controversial. Moreover, few studies have utilized simultaneous detection of cytokines in local tissues and saliva to determine whether salivary cytokines could reflect the fact of local lesions.
Methods:  IFN-gamma and IL-4 were determined simultaneously in lesions and whole unstimulated saliva (WUS) from OLP patients with various clinical forms.
Results:  In OLP lesions, both IFN-gamma and IL-4 in erythematous/ulcerated OLP were higher significantly than that in control specimens. In WUS, however, only IFN-gamma of erythematous/ulcerated OLP was increased compared with control. Remarkably, IFN-gamma and IL-4 in WUS showed a more significant correlation to those in local tissues of all subjects.
Conclusion:  These results indicate that both IFN-gamma and IL-4 may play more important role in pathogenesis of erythematous/ulcerated OLP, and changes of these proinflammatory cytokines in WUS may reflect the status of the OLP lesion.     

Cytokine-producing cells in peripheral blood of children with coeliac disease secrete cytokines with a type 1 profile.

Coeliac disease (CoD) is a small intestinal disorder characterized by crypt cell hyperplasia and villous atrophy, and the production of cytokines from T cells and macrophages are of importance for the histological changes seen in CoD. A peroral immunization with an antigen, which gives rise to a mucosal immune response, may increase the levels of circulating cytokine-producing cells, and we wanted to obtain a better picture of an eventual emergence of activated circulating T cells in the peripheral blood in children with CoD. The cytokine expression of interferon-gamma (IFN-gamma), IL-4, IL-6 and IL-10 was measured at the single-cell level by an ELISPOT method in 38 children with CoD. The numbers of IFN-gamma-producing cells in the peripheral blood was increased in children with untreated CoD (P < 0.01) and after gluten challenge (P < 0.05) compared with healthy controls. Also, the numbers of IL-6-producing cells were increased (P < 0.05) after gluten challenge compared with the healthy controls. A paired comparison showed that the numbers of IFN-gamma-producing cells increased after gluten challenge (P < 0.05), whereas no such change was seen for IL-4- or IL-10-producing cells. There were no differences in the numbers of IFN-gamma-producing cells between the group of children with treated CoD and the groups of untreated or challenged CoD children. IL-4 production correlated with serum levels of total IgE. These results show that circulating mononuclear cells in children with active CoD secrete cytokines compatible with a type 1 response.     

Beneficial effects of cannabinoids (CB) in a murine model of allergen-induced airway inflammation: role of CB1/CB2 receptors

The endocannabinoid system (ECS) consists of two cannabinoid (CB) receptors, namely CB₁ and CB₂ receptor, and their endogenous (endocannabinoids) and exogenous (cannabinoids, e.g. delta-9-tetrahydrocannabinol (THC)) ligands which bind to these receptors. Based on studies suggesting a role of THC and the ECS in inflammation, the objective of this study was to examine their involvement in type I hypersensitivity using a murine model of allergic airway inflammation. THC treatment of C57BL/6 wildtype mice dramatically reduced airway inflammation as determined by significantly reduced total cell counts in bronchoalveolar lavage (BAL). These effects were greatest when mice were treated during both, the sensitization and the challenge phase. Furthermore, systemic immune responses were significantly suppressed in mice which received THC during sensitization phase. To investigate a role of CB_1/2 receptors in this setting, we used pharmacological blockade of CB₁ and/or CB₂ receptors by the selective antagonists and moreover CB₁/CB₂ receptor double-knockout mice (CB₁^−/−/CB₂^−/−) and found neither significant changes in the cell patterns in BAL nor in immunoglobulin levels as compared to wildtype mice. Our results indicate that the activation of the ECS by applying the agonist THC is involved in the development of type I allergies. However, CB₁/CB₂ receptor-independent signalling seems likely in the observed results.     

Allergic immune-regulatory effects of Adlay Bran on an OVA-immunized mice allergic model

Allergy is an inflammation associated with an elevated T helper (Th) 2 lymphocyte responses to allergens and elevated serum IgE levels and cytokines. In one of our previous studies using a cell model, various flavonoids were found to be involved the anti-inflammatory effects of adlay bran. The present study investigated the effect of the ethyl-acetate fraction of ethanolic extract of adlay bran (ABE-EtOAc) in an ovalbumin (OVA)-immunized murine model. Six-week-old female BALB/c mice underwent OVA sensitization and were used as an allergy model. An orogastric gavage was used to force feed these mice with 240 mg/kg ABE-EtOAc from their sixth week through their twelfth week. Immune reactions were determined by measuring changes in Th2-type cytokine (IL-4 and IL-5) levels and production of antibodies. ABE-EtOAc was found capable of regulating the Th1/Th2 immune reaction through its regulation of IL-2 and IL-4. It also significantly reduced the production of anti-OVA IgE antibodies (10%), increased the secretion of IFN-γ and decreased the secretion of IL-6 (38%). These results suggest that adlay bran extract can reduce an allergic reaction by balancing Th1/Th2 immune responses and that it might be used in the treatment of this condition.     

Effector role of neonatal hepatic CD8+ lymphocytes in epithelial injury and autoimmunity in experimental biliary atresia

BACKGROUND & AIMS: Lymphocytes populate the livers of infants with biliary atresia, but it is unknown whether neonatal lymphocytes regulate pathogenesis of disease. Here, we investigate this question by examining the role of T lymphocytes in the destruction of extrahepatic bile ducts of neonatal mice using an experimental model of biliary atresia. METHODS: Inoculation of neonatal mice with rhesus rotavirus followed by multistaining flow cytometry to quantify expression of interferon-gamma by hepatic lymphocytes, and real-time polymerase chain reaction for mRNA expression of pro-inflammatory cytokines. This was followed by determining the consequences of antibody-mediated depletion of lymphocyte subtypes on the development of biliary obstruction, and coculture and cell transfer experiments to investigate the effector role of lymphocyte subtypes on neonatal biliary disease. RESULTS: Rotavirus infection results in overexpression of interferon-gamma by neonatal hepatic T cells. Among these cells, depletion of CD4(+) cells did not change the course of inflammatory injury and obstruction of neonatal bile ducts. In contrast, loss of CD8(+) cells remarkably suppressed duct injury, prevented luminal obstruction, and restored bile flow. Coculture experiments showed that rotavirus-primed, but not na?ve, CD8(+) cells were cytotoxic to cholangiocytes. In adoptive transfer experiments, we found that primed CD8(+) cells preferentially homed to extrahepatic bile ducts of neonatal mice and invaded their epithelial lining. CONCLUSIONS: Primed neonatal CD8(+) cells can activate a pro-inflammatory program, target diseased and healthy duct epithelium, and drive the phenotypic expression of biliary atresia, thus constituting a potential therapeutic target to halt disease progression.