急性心肌梗死大鼠心肌组织趋化因子及其受体mRNA表达的观察

目的:探讨急性心肌梗死大鼠心肌局部趋化因子和T细胞趋化因子受体的表达,揭示AMI后T细胞浸润心肌组织的机制。方法:结扎冠脉左前降支建立AMI大鼠模型,用半定量RT-PCR方法分析心肌梗死区和非梗死区趋化因子的表达,包括γ干扰素诱导的单核因子(MIG),正常T细胞表达和分泌、活化时表达下降的因子(RANTES),巨噬细胞炎性蛋白-1α(MIP-1α),以及T细胞趋化因子受体的表达(包括CXCR3、CCR3、CCR5)。HE染色切片进行心肌梗死区和非梗死区淋巴细胞计数分析。结果:心肌梗死区和非梗死区趋化因子RANTES、MIP-1α、MIG的mRNA表达于术后3天开始升高,1周达峰值,然后开始下降,8周降至正常,而趋化因子受体的表达没有明显改变。AMI大鼠心脏梗死区和非梗死区均可见淋巴细胞浸润,梗死区1周达高峰(81.0±10.3vs2.6±1.1,P<0.05),非梗死区2周达高峰(19.0±8.0vs3.2±0.8,P<0.05)。RANTES和MIP-1α的表达与淋巴细胞浸润显著相关。结论:AMI后心肌局部趋化因子表达增高,可能是诱导T细胞浸润心肌组织的始动因子。     

趋化因子及其受体与GVHD研究进展

趋化因子为一分子量为 811kD的小分子蛋白质超家族 ,其受体为Gi Go蛋白偶联受体 ,目前已发现有19个。趋化因子及其受体与GVHD的关系是目前移植免疫研究的一个新兴领域。实体器官移植后趋化因子有一时相性表达 ,但CXCL8(IL 8)与骨髓移植后GVHD的关系尚有争议。趋化因子及受体表达与GVHD发生的组织选择性及慢性GVHD病变的发生有关。CCL3(MIP 1α)及其受体CCR5对GVHD中自身抗体产生、受体特异性的CTL的组织选择性募集及活化等过程都具有重要作用。     

趋化因子在HBV感染发病中的作用

乙型肝炎是一种以局部炎性为主的感染性疾病,乙型肝炎病毒(HBV)感染宿主细胞后可诱导宿主细胞中趋化因子分泌及其受体表达,趋化因子/受体的相互作用进一步介导中性粒细胞、淋巴细胞等向炎症部位聚集,参与组织损伤;同时诱导T、B 细胞分化成熟,对乙型肝炎的发展与转归、肝组织的损伤与修复有重要影响.HBV引发的慢性乙型肝炎(CHB)以Th1细胞性炎性反应为主,研究表明乙型肝炎中某些趋化因子在肝脏高表达,其受体CXCR3和CCR5在Th1细胞高表达.趋化因子尤其是CXC和CC亚家族趋化因子在趋化Th1细胞中发挥重要的作用.     

趋化因子受体3及其配体参与结核病免疫机制和诊断的研究进展

趋化因子（CXCL）9、CXCL10、CXCL11是目前研究较多且与结核免疫密切相关的3种趋化因子，同属于趋化因子受体3(CXCR3)配体。CXCL9、CXCL10、CXCL11主要作用于活化的CD4细胞（CD4+T细胞）、细胞毒性T淋巴细胞（CD8+T细胞）和自然杀伤（NK）细胞，参与结核病发病及免疫过程，在细胞免疫中发挥重要作用。本文总结了近5年CXCL9、CXCL10及CXCL11在结核病免疫机制和检测中作用的相关研究，以期为结核病诊断和疗效评估提供新的方法。     

慢性乙肝患者趋化因子IP-10及其受体CXCR3的检测

在慢性乙肝病毒感染过程中 ,淋巴细胞向受病毒感染肝组织的迁移、浸润 ,对于抗病毒免疫应答及炎症反应的发生起着决定性作用。而对其机理的研究尚未取得令人满意的答案。近年来 ,对趋化因子与其受体的相互作用的研究表明 ,激活的淋巴细胞可表达特定的受体分子 ,并受相应趋化因子吸引、招募后 ,定向迁移至局部组织 ,产生免疫应答或炎症反应〔1〕。其中趋化因子受体CXCR3与其配体干扰素诱导蛋白 10 (IFN inducibleMr10× 10 3 protein ,IP 10 )的相互作用已成为研究某些炎症发生机制的突破点〔2 ,3〕。本实验旨在研究慢性乙肝患者中IP 10…     

异基因骨密质来源间充质干细胞对小鼠急性GVHD 的防治作用及其机制研究

目的:明确异基因骨密质来源的间充质干细胞(CB-MSCs)是否能有效防治急性GVHD,并进一步探讨其可能的治疗机制。方法:采用骨密质碎片法从C57BL/6(H-2b)小鼠分离和扩增MSCs。通过构建小鼠allo鄄HSCT 后GVHD 模型:雌性供鼠C57BL/6 (H-2b)寅雄性受鼠BALB/ c (H-2d),然后观察CB-MSCs 移植对GVHD 的影响。本实验小鼠共分为4 组:淤单纯照射组;于GVHD 组; GVHD+MSCs 组;榆正常对照组。在GVHD 诱导后不同时间点观察各组小鼠生存率、体重变化和临床GVHD 积分;应用ELISA 方法检测各组小鼠外周血细胞因子(TNF-β、IFN-β和IL-4) 和趋化因子(CCL5、CXCL9 和CXCL10)浓度;应用流式细胞术检测各组小鼠外周血CD4+ CD25+ Foxp3+ 调节性T 细胞(Treg 细胞)百分比和CD3+ T 细胞表面趋化因子受体CXCR3、CCR5 和CCR7 的表达。此外,我们还应用实时定量逆转录PCR(Real-time RT-PCR)方法检测了各组小鼠骨髓中T-bet 和GATA-3 的mRNA 表达水平。结果:CB-MSCs 能显著提高GVHD 小鼠生存率、减少其体重缺失,并显著降低临床GVHD 积分;CB-MSCs 对GVHD 的防治作用可能与降低外周血TNF-β、IFN-β、CCL5、CXCL9 和CXCL10 浓度,增加Treg 细胞百分比,下调T 细胞表面CXCR3、CCR5 的表达和上调CCR7 的表达有关。此外,诱导骨髓Th1/ Th2 平衡向抗炎的Th2 极倾斜可能也是CB-MSCs 对GVHD 发挥治疗作用的机制之一。结论:异基因CB-MSCs 显著增加了GVHD 小鼠生存率。其治疗机制可能与CB-MSCs 能够减少炎性细胞因子和趋化因子的释放,诱导Treg 的生成,调控T 细胞表面趋化因子受体的表达,以及纠正Th1/ Th2 的失衡有关。     

淋巴细胞归巢趋化因子SLC的研究进展

次级淋巴趋化因子 (SLC)是体内重要的CC趋化因子成员 ,被认为是第一个参与体内淋巴细胞归巢的趋化因子 ,其组织分布主要是外周淋巴组织或器官 ,趋化体内多种淋巴细胞 (包括T细胞、B细胞、NK细胞、树突状细胞 )到外周淋巴组织或器官 ,这一粘附过程的主要涉及二种整合素α1β2 (LFA)和α4 β7,它们的配体分别时表达于HEV表面的ICAM 1或ICAM 2和MAdCAM ,另外α淋巴毒素和核因子κΒ诱导激酶也可通过SLC影响淋巴细胞归巢。基于其对多种效应细胞的趋化和调节作用 ,目前开展了许多应用研究工作。无论是重组蛋白注射还是基因修饰瘤苗均显示极强的抗肿瘤作用 ,在肿瘤局部和全身检测到系统性和局部免疫反应 ,包括CD4 +T细胞、CD8+T细胞和树突状细胞浸润 ,并伴有Th1类细胞因子上调 ;动物实验显示SLC可以通过树突状细胞调节先天性或 /和获得性免疫 ,参与抗急性炎症作用 ;在抗接触性超敏反应研究中 ,SLC抗体可以抑制郎格罕氏细胞迁移到淋巴结 ,这一研究提示一个新的治疗和预防皮肤变态反应性疾病的思路 ,即通过注射抗体或趋化因子阻断剂来干预抗原递呈细胞的功能从而抑制效应T细胞的致敏、活化     

小鼠NKT细胞在5型腺病毒感染所致肝损伤早期的免疫调节作用

目的 使用5型腺病毒(AdS)感染小鼠模型来研究肝脏NKT细胞(natural killer Tcell)在肝损伤早期的免疫调节机制.方法 C57BL/6小鼠尾静脉注射1.5×109PFU和3×109PFUAdS病毒以构建两个剂量组病毒感染的小鼠肝损伤模型,通过观察病毒感染后5 d内小鼠肝组织病理学及小鼠血清丙氨酸转氨酶/天门冬氨酸转氨酶(ALT/AST)水平改变来判断肝损伤程度,使用流式细胞术(FACS)分析感染5 d内肝单个核细胞亚群比例、NKT细胞表面FasL表达水平以及NKT细胞合成IL-4和IFN-γ水平的变化,应用RT-PCR检测小鼠肝内趋化因子及趋化因子受体表达水平.结果 高滴度(3×109 PFU)的AdS病毒感染小鼠1 d后,小鼠肝脏内NKT细胞明显增加,其表面FasL表达上调,肝脏NKT细胞合成IL-4和IFN-γ的水平明显增加,肝组织内淋巴细胞浸润明显;低滴度AdS病毒(1.5×109PFU)感染小鼠后,肝脏NKT细胞比例变化不明显,CD8+T细胞在肝脏的浸润明显弱于高滴度AdS病毒感染;RT-PCR检测结果 显示:3×109PFU AdS病毒感染2 d后,小鼠肝内活化后可调节的及正常的T细胞分泌的趋化因子(RANTES)、人干扰素诱导蛋白10(IP-10)以及巨噬细胞炎症蛋白(MIP)-1β表达增加,3d后相关趋化因子受体CCR5、CCR1、CXCR3表达上调.结论 NKT细胞在淋巴细胞向肝脏趋化的过程中起重要的作用,这种作用与病毒感染诱导NKT细胞合成IL-4和IFN-γ及上调其表面的FasL,从而促进肝细胞内IP-10、Mig等趋化因子的产生有关.     

ConA刺激对CD4~+CD25~+调节性T细胞趋化特性及其表面趋化因子受体CCR4/CCR6表达的影响

目的体外动态观察ConA激活的调节性T细胞表面趋化因子受体的表达变化及其趋化特性,为利用调节性T细胞诱导免疫耐受提供线索。方法常规分离正常健康人外周血单个核细胞,免疫磁珠阴性分选CD4+T细胞;加FITC-An-tiCD4抗体,APC-AntiCD25抗体,PE-AntiCD127抗体上流式细胞仪分选出CD4hiCD127loCD25hi-int细胞。纯化的调节性T细胞与CD4+CD25-T分别用ConA(10μg/mL)刺激0、24、48h后,用趋化因子CCL1、CCL5、CCL20、CCL22做趋化实验,观察各趋化因子作用下调节性T细胞与CD4+CD25-T细胞的趋化特性。同时,流式细胞仪检测CCR4与CCR6的表达。结果分离得到的调节性T细胞纯度为97.4%,活细胞率为95%,得率:4.1%。CCL1、CCL20、CCL22均可趋化调节性T细胞,且在ConA激活后趋化效率随时间而改变。CCL1与CCL22对调节性T细胞的趋化指数显著高于CD4+CD25-T细胞;CCL20对调节性T细胞和CD4+CD25-T细胞趋化指数都很高;CCL5对调节性T细胞趋化性则显著弱于CD4+CD25-T细胞。ConA刺激后...     

一种新的趋化因子I-TAC

趋化因子是一系列具有募集细胞迁移功能的细胞因子。干扰素诱导的T细胞α亚族趋化剂(I-TAC)是近年新发现的一种趋化因子,属于CXC家族。已经发现I-TAC不仅具有指导细胞迁移的趋化因子的基本功能,而且还参与调控血管生成及细胞增殖的过程。研究I-TAC结构、生物学功能以及与疾病的关系具有重要的意义。     

Upon dendritic cell (DC) activation chemokines and chemokine receptor expression are rapidly regulated for recruitment and maintenance of DC at the inflammatory site.

Dendritic cells (DC) are highly motile antigen-presenting cells that are recruited to sites of infection and inflammation to antigen uptake and processing. Then, to initiate T cell-dependent immune responses, they migrate from non-lymphoid organs to lymph nodes and the spleen. Since chemokines have been involved in human DC recruitment, we investigated the role of chemokines on mouse DC migration using the mouse growth factor-dependent immature DC line (D1). In this study, we characterized receptor expression, responsiveness to chemoattractants and chemokine expression of D1 cells during the maturation process induced by lipopolysaccharide (LPS). MIP-1alpha and MIP-5 were found to be the most effective chemoattractants, CCR1 was the main receptor expressed and modulated during LPS treatment, and MIP-2, RANTES, IP-10 and MCP-1 were the chemokines modulated during DC maturation. Thus, murine DC respond to a unique set of CC and CXC chemokines, and the maturational stage determines the program of chemokine receptors and chemokines that are expressed. Since CCR1 is modulated during the early phases of DC maturation, our results indicate that the CCR1 receptor may participate in the recruitment and maintenance of DC at the inflammatory site.     

CCR4 is an up-regulated chemokine receptor of peripheral blood memory CD4+ T cells in Crohn's disease

Several chemokine receptors are expressed selectively on the surface of T cells depending on their polarization. The aim of this study was to characterize chemokine receptor expression in peripheral blood memory T cells in Crohn's disease (CD) and ulcerative colitis (UC), and to correlate the expression with disease activity. Peripheral blood mononuclear cells (PBMCs) were obtained from 24 patients with CD, 30 patients with UC, 24 normal controls and 10 disease controls. PBMCs were stained by anti-CCR3, CCR4, CCR5, CXCR3, CD4, CD8, CD45RO and beta 7 integrin, and the expression of the chemokine receptors were determined by flow cytometry. CCR4 expression on memory T cells was significantly lower in UC than in CD or normal controls, and that of memory CD4+ T and beta 7(high) memory CD4+ T cells was significantly higher in CD than in UC or normal controls. CCR4 expression on memory CD4+ T cells exhibited significant positive correlation with disease activity in CD, and this decreased significantly after treatment. Such a decrease was not found in the disease controls. CCR5 and CXCR3 expression on memory CD8+ T cells was significantly lower in CD than in normal controls. CXCR3 expression on beta 7(high) memory CD4+ T and CXCR3 expression on memory CD8+ T cells were lower in UC than in normal controls. These findings suggest that in peripheral blood memory T cells, chemokine receptor expression is different between CD and UC. Enhancement of CCR4 and suppression of CCR5 and CXCR3 seem to be the characteristic chemokine receptor profile in peripheral blood memory T cells of CD.     

Expression of chemokines in GVHD target organs is influenced by conditioning and genetic factors and amplified by GVHR.

Graft-versus-host disease (GVHD) is the most significant clinical problem that arises after allogeneic hematopoietic cell transplantation. Because chemokines induced by proinflammatory conditioning treatment may promote T-cell migration into GVHD target tissues, we addressed the influence of conditioning on chemokine expression in GVHD target organs. Our results showed that (1) conditioning leads to rapid and transient chemokine upregulation in GVHD target tissues before the time of GVHD-associated T-cell infiltration; (2) conditioning intensity and mouse strain influence chemokine expression in GVHD target organs; and (3) compared with syngeneic bone marrow transplantation, allogeneic bone marrow transplantation led to marked amplification of chemokine expression in GVHD target organs after myeloablative conditioning. This is also reflected by chemokine protein expression that is measured in the serum and colon. Intestines showed the greatest sensitivity to conditioning intensity, and chemokines affecting T-helper type 1 cells (eg, interferon gamma-inducible protein 10 [CXCL10]) were most strongly expressed there after conditioning and during GVHD. However, severity of GVHD was not significantly different between recipients of CXCR3+/+ or CXCR3-/- splenocytes, indicating that this chemokine pathway does not play a critical role. In summary, our data show that conditioning and recipient strain influence chemokine expression in GVHD target organs and that GVH alloreactivity markedly amplifies this expression, thus contributing to the inflammatory cascade associated with tissue GVHD.     

Impaired CD4 and CD8 T cell phenotype and reduced chemokine secretion in recent-onset type 1 diabetic children

Although the role of the T cell-mediated autoimmune reaction in type 1 diabetes (T1D) is conclusive, studies including data from human circulating CD4(+) and CD8(+) lymphocytes subsets during the disease onset and posterior development are scarce. Further, chemokines and chemokine receptors are key players in the migration of pathogenic T cells into the islets of non-obese diabetic mice developing T1D, but few studies have investigated these markers in human T1D patients. We studied the expression of T helper 1 (Th1)- and Th2-associated chemokine receptors, and the two isoforms of CD45 leucocyte antigen on CD4(+) and CD8(+) lymphocytes from T1D and healthy children, as well as the secretion of chemokines in cell supernatants in peripheral blood mononuclear cells. Our results showed increased expression of CCR7 and CD45RA and reduced CD45RO on CD8(+) cells among recent-onset T1D patients. The percentages of CD4(+) cells expressing CXC chemokine receptor 3 (CXCR3), CXCR6 and CCR5, and the secretion of interferon-gamma-induced protein-10, monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1alpha and MIP-1beta was lower among diabetics. Low expression of Th1-associated receptors and secretion of chemokines, together with an increased amount of CD8(+) cells expressing CD45RA and CCR7 in T1D patients therefore might represent suboptimal Th function in T1D, leading to impaired T cytotoxic responses or alternatively reflect a selective recruitment of Th1 cells into the pancreas.     

Chemokine responsiveness of CD4+ CD25+ regulatory and CD4+ CD25− T cells from atopic and nonatopic donors

Background:  Allergic inflammation is associated with Th2-type T cells, which can be suppressed by CD4+ CD25+ regulatory T cells (Tregs). Both express chemokine receptors (CCR) 4 and CCR8, but the dynamics of expression and effect of atopic status are unknown.
Objective:  To examine the expression of chemokine receptors by CD4+ CD25+ and CD4+ CD25− T cells from atopic and nonatopic donors, and document response to allergen stimulation in vitro .
Methods:  Chemokine receptor expression was examined by flow cytometry and quantitative PCR of CD4+ CD25hi and CD4+ CD25− T cells from atopics and nonatopics. Responsiveness to chemokines was by actin polymerization. Dynamics of chemokine receptor expression in 6-day allergen-stimulated cultures was analysed by carboxyfluoroscein succinimidyl ester labelling.
Results:  CD4+ CD25hi Tregs preferentially expressed CCR3, CCR4, CCR5, CCR6 and CCR8. CD4+ CD25hi Tregs responded to the chemokine ligands for CCR4, CCR6 and CCR8 (CCL17, 22, 20 and 1 respectively), with no differences between atopic and nonatopic donors. Over 6-day allergen stimulation, CD4+ CD25+ T-cells downregulated CCR4 and upregulated CCR7, in contrast to CD4+ CD25− effector cells, which downregulated CCR7 and upregulated CCR4.
Conclusions:  CCR4, CCR6 and CCR8 have potential roles in localization of both CD4+ CD25+ regulatory and CD4+ CD25− effector T cells to sites of allergic inflammation. Upregulation of CCR7 and downregulation of CCR4 upon allergen stimulation of Tregs may allow their recirculation from sites of inflammation, in contrast to retention of effector T cells.     

Pleiotropic effects of CXC chemokines in gastric carcinoma: differences in CXCL8 and CXCL1 expression between diffuse and intestinal types of gastric carcinoma

CXC chemokines modulate host immunity, neovascularization, growth and invasive behaviour of tumours. Despite their relevance in tumour biology, chemokine expression in intestinal- and diffuse-type gastric carcinoma, which exhibit a completely different growth pattern, has not been investigated in detail. In this study, expression of the CXC chemokines CXCL8 [interleukin (IL)-8], CXCL1 [growth-related oncogene alpha (Gro alpha)], CXCL9 [monokine induced by interferon (IFN)-gamma] and CXCL10 [IFN-gamma-inducible protein-10 (IP-10)] and the corresponding chemokine receptors CXCR1-3 was investigated by immunohistochemistry in intestinal- and diffuse-type gastric carcinoma. Tumour cells of all patients expressed CXCL8. CXCL8 expression was significantly stronger in tumour cells of diffuse- rather than intestinal-type gastric carcinoma (P < 0.01) as determined by a semiquantitative score. CXCL1 was expressed almost exclusively by diffuse- but not intestinal-type carcinoma cells. The corresponding chemokine receptors, CXCR1 and CXCR2, were found on carcinoma cells. Furthermore, CXCL8 expression correlated with number of tumour vessels (P < 0.01), suggesting an angiogenetic function in gastric carcinoma not only in vitro but also in vivo. CXCL10 and CXCL9, attractants for T cells, were expressed by peritumorous macrophages in close proximity to IFN-gamma-producing CXCR3-positive T cells in both tumour types. These chemokines may attract gastric carcinoma-infiltrating T cells via an IFN-gamma-mediated pathway and enhance host immunity against the tumour. In gastric carcinoma a complex interplay between CXC-chemokine signals derived from both tumour cells and tumour-infiltrating immune cells may exhibit pleiotropic effects in tumour biology that go far beyond their originally described functions as leucocyte chemoattractants. Because CXCL8 and CXCL1, which are known to increase growth and invasive behaviour of malignant tumours, are significantly stronger expressed in diffuse- than intestinal-type gastric carcinoma, one may speculate that these chemokines influence the different growth pattern of gastric carcinoma types.     

Distinct effect of CD40 and TNF-signaling on the chemokine/chemokine receptor expression and function of the human monocyte-derived dendritic cells

A key and limiting step in the process of human monocyte-derived dendritic cells （mDCs） for clinical use is their in vitro maturation and in vivo migration. We previously observed that CD40 signal facilitated human mDC growth and maturation. To further explore this process, mDCs generated with GM-CSF and IL-4 were co-cultured with apoptotic tumor cells for 24 hours, followed by incubating with anti-CD40 monoclonal antibody or TNF-a for 48 hours to generate mature DCs. The chemokine/chemokine receptor expression and functions of mature DCs upon various stimuli were determined. The expression of costimulatory molecules on apoptotic tumor cell-loaded mature DCs co-cultured with either anti-CD40 antibody （anti-CD40-DCs） or TNF-a （TNF-DCs） were up-regulated compared to immature DCs, consistent with the abilities of these cytokine to drive DC maturation in vitro. The mRNA levels of chemokines such as stromal cell-derived factor-1a （SDF-1a）, EBV-induced molecule 1 ligand chemokine （ELC）, and IFN inducible protein-10 （IP-10） in anti-CD40 activated DCs were increased and the dendritic cell-specific chemokine 1 （DC-CK1） was moderately up-regulated as compared with other mature DCs. The corresponding chemokine receptors CXCR4 and CCR7 of anti-CD40-DCs were significantly expressed. The CXCR3 expression on activated T cells stimulated by anti-CD40-DCs was also increased. Moreover, the anti-CD40-DCs had a stronger ability to stimulate T cell proliferation than any other DCs. The NF-xB activity was much higher in anti-CD40-DCs than that of TNF-DCs. These results offer further evidence of the importance of the CD40 signal in developing efficient human DC vaccines for cancer immune therapy. Cellular ＆ Molecular Immunology.     

Human β defensin‐3 induces chemokines from monocytes and macrophages: diminished activity in cells from HIV‐infected persons

Human β defensin‐3 (hBD‐3) is an antimicrobial peptide with diverse functionality. We investigated the capacity of hBD‐3 and, for comparison, Pam3CSK4 and LL‐37 to induce co‐stimulatory molecules and chemokine expression in monocytes. These stimuli differentially induced CD80 and CD86 on the surface of monocytes and each stimulant induced a variety of chemokines including monocyte chemoattractant protein 1 (MCP‐1), Gro‐α, macrophage‐derived chemokine (MDC) and macrophage inflammatory protein 1β (MIP1β), while only hBD‐3 and Pam3CSK4 significantly induced the angiogenesis factor, vascular endothelial growth factor (VEGF). Human BD‐3 induced similar chemokines in monocyte‐derived macrophages and additionally induced expression of Regulated upon activation normal T‐cell expressed and presumably secreted (RANTES) in these cells. Comparison of monocytes from HIV⁺ and HIV^– donors indicated that monocytes from HIV⁺ donors were more likely to spontaneously express certain chemokines (MIP‐1α, MIP‐1β and MCP‐1) and less able to increase expression of other molecules in response to hBD‐3 (MDC, Gro‐α and VEGF). Chemokine receptor expression (CCR5, CCR2 and CXCR2) was relatively normal in monocytes from HIV⁺ donors compared with cells from HIV^– donors with the exception of diminished expression of the receptor for MDC, CCR4, which was reduced in the patrolling monocyte subset (CD14⁺ CD16⁺⁺) of HIV⁺ donors. These observations implicate chemokine induction by hBD‐3 as a potentially important mechanism for orchestrating cell migration into inflamed tissues. Alterations in chemokine production or their receptors in monocytes of HIV‐infected persons could influence cell migration and modify the effects of hBD‐3 at sites of inflammation.     

I-TAC/CXCL11 is a natural antagonist for CCR5

The selective CXC chemokine receptor 3 (CXCR3) agonists, monokine induced by interferon-gamma (IFN- gamma)/CXC chemokine ligand 9 (CXCL9), IFN-inducible protein 10/CXCL10, and IFN-inducible T cell alpha chemoattractant (I-TAC)/CXCL11, attract CXCR3+ cells such as CD45RO+ T lymphocytes, B cells, and natural killer cells. Further, all three chemokines are potent, natural antagonists for chemokine receptor 3 (CCR3) and feature defensin-like, antimicrobial activities. In this study, we show that I-TAC, in addition to these effects, acts as an antagonist for CCR5. I-TAC inhibited the binding of macrophage-inflammatory protein-1alpha (MIP-1alpha)/CC chemokine ligand 3 (CCL3) to cells transfected with CCR5 and to monocytes. Furthermore, cell migration evoked by regulated on activation, normal T expressed and secreted (RANTES)/CCL5 and MIP-1beta/CCL4, the selective agonist of CCR5, was inhibited in transfected cells and monocytes, respectively. In two other functional assays, namely the release of free intracellular calcium and actin polymerization, I-TAC reduced CCR5 activities to minimal levels. Sequence and structure analyses indicate a potential role for K17, K49, and Q51 of I-TAC in CCR5 binding. Our results expand on the potential role of I-TAC as a negative modulator in leukocyte migration and activation, as I-TAC would specifically counteract the responses mediated by many "classical," inflammatory chemokines that act not only via CCR3 but via CCR5 as well.     

Expression of CC and CXC chemokines and chemokine receptors in human leprosy skin lesions

We have investigated the expression of chemokines and their receptors in leprosy skin lesions using immunohistochemistry. Skin biopsies from 25 leprosy patients across the leprosy spectrum, 11 patients undergoing type I reversal reactions and four normal donors were immunostained by ABC peroxidase method using antibodies against CC and CXC chemokines and their receptors. Using an in situ hybridization technique we have also studied the expression of monocyte chemoattractant protein 1 (MCP-1), RANTES and interleukin (IL)-8 chemokines mRNA in leprosy skin lesions. Chemokines and receptor expression was detected in all leprosy skin biopsies. Expression of CC chemokines MCP-1 (P < 0.01) and RANTES (P < 0.01) were elevated significantly in borderline tuberculoid leprosy in reversal reaction compared to non-reactional borderline tuberculoid leprosy, but there was no difference in the expression of IL-8 chemokine. Surprisingly, there was no significant difference in the expression of CC (CCR2 and CCR5) and CXC (CXCR2) chemokine receptors across the leprosy spectrum. Similarly, there was no significant difference in the expression of mRNA for MCP-1, regulated upon activation normal T cell expressed and secreted (RANTES) and IL-8 chemokines. Here, the presence of a neutrophil chemoattractant IL-8 in leprosy lesions, which do not contain neutrophils, suggests strongly a role of IL-8 as a monocyte and lymphocyte recruiter in leprosy lesions. These results suggest that the chemokines and their receptors, which are known to chemoattract T lymphocytes and macrophages, are involved in assembling the cellular infiltrate found in lesions across the leprosy spectrum.