HIV-1辅受体的配体细胞内双表达对病毒感染的阻断作用

目的　观察Ⅰ型人免疫缺陷病毒 (HIV 1)辅受体的配体———RANTES和SDF 1α双表达于人淋巴细胞对各种嗜性HIV 1毒株感染的阻断作用。方法　用 pLNCX R K S K重组逆转录病毒液感染原代人外周血淋巴细胞 (PBLs) ,抗神经生长因子受体 (NGFR) 免疫磁珠法分离转化成功的PBLs,流式细胞仪检测筛选效率 ;HIV 1M嗜性、T嗜性和双嗜性毒株攻击转化PBLs ,检测HIV 1逆转录酶活性和 p2 4抗原分泌 ,以观察抗HIV 1感染的作用 ;同时进行转化PBLs表面CD3、CD4、CCR2、CCR5和CXCR4表达及破伤风毒素刺激后3 H 胸苷 (thymidine)掺入量检测 ,观察HIV 1辅受体配体的双表达对人PBLs正常生物学功能的影响。结果　抗 NGFR 免疫磁珠法获得了转化成功的PBLs,流式细胞仪检测发现pLNCX R K S K转染组 92 %以上的PBLs鼠抗NGFR标记物为阳性 ;HIV 1M嗜性、T嗜性和双嗜性毒株攻击后 ,pLNCX R K S K转化PBLs可以见到明显的逆转录酶活性和 p2 4抗原分泌抑制 ,并且在感染后第 12～ 2 0天时抑制作用最强 ;pLNCX R K S K转化PBLs表面CD3、CD4和CCR2表达水平无明显变化 ,而CCR5和CXCR4表达水平降低 ;破伤风毒素刺激后的转化PBLs仍具有主动增殖的能力。结论　HIV 1辅受体的配体通过在人PBLs内双表达 ,使HIV 1两类主要辅受体表型剔除 ,基本阻断了     

Ⅰ型人类免疫缺陷病毒包膜糖蛋白120V4区氨基酸位点突变对感染细胞能力的影响

目的 探讨Ⅰ型人类免疫缺陷病毒(HIV-1)包膜糖蛋白120 V4区氨基酸位点发生突变对CCR5及CXCR4嗜性毒株感染靶细胞能力的影响.方法 根据ADA株为CCR5嗜性毒株,只具有感染CCR5细胞的能力;HXB2株为CXCR4嗜性毒株,只具有感染CXCR4细胞的能力,通过重叠延伸剪接的方法,构建CCR5嗜性及CXCR4嗜性毒株V4区丙氨酸替换突变体.将突变体表达载体与带有荧光报告基因的HIV骨架基因表达载体共同转染真核细胞,制备假病毒颗粒.采用酶联免疫吸附(ELISA)法检测假病毒中HIV-1 P24抗原,对假病毒进行定量.将假病毒接20、40 ng感染U87.CD4.CCR5和U87.CD4.CXCR4细胞,以野生株ADA和HXB2毒株为对照,通过荧光素酶(RLU)测定,检测HIV-1 V4区氨基酸386-417位点各突变体假病毒对细胞的感染能力.结果 成功构建HIV-1 ADA和HXB2株V4区丙氨酸替换突变体,各获得10株突变体.在ADA株和HXB2株,389-391及414-417位点均发生丙氨酸替换突变体,无论是用20ng,还是40 ng假病毒感染,对CCR5及CXCR4细胞的感染能力均完全丧失[(0±0)％];在ADA株,400-403和408-410位点发生丙氨酸替换突变体,当假病毒在20 ng时,感染细胞的能力达到了(124±35)％和(182±29)％;在40ng时,感染能力达到了(127±8)％和(134±16)％;在HXB2株,395-397位点发生丙氨酸替换突变体,当假病毒在20 ng时,感染能力达到了(144±42)％;在40 ng时,感染能力达到了(121±18)％;两株在其他位点发生丙氨酸替换突变体,但仅保留部分感染细胞能力( 15％ ～ 84％).结论 HIV-1包膜糖蛋白V4区389-391及414-417位点氯基酸发生丙氨酸突变,使病毒完全丧失感染靶细胞能力.     

过敏性支气管哮喘儿童正常T淋巴细胞表达和分泌的活性调节蛋白基因启动子-28位基因多态性研究

目的　探讨中国儿童正常T淋巴细胞表达和分泌的活性调节蛋白 (RANTES)基因启动子 - 2 8位基因多态性对儿童过敏性哮喘的影响。方法　采用聚合酶链反应 限制性片段长度多态性(PCR RFLP)方法 ,对 10 0例过敏性哮喘儿童 (A组 )的RANTES基因进行多态性分析 ,用化学发光法检测患者血浆总IgE浓度 ,用酶联免疫吸附试验 (ELISA)检测血浆中RANTES浓度 ,用全自动血细胞计数仪进行嗜酸粒细胞计数 ;并与 90名健康儿童 (B组 )进行比较。结果　 (1)RANTES启动子 - 2 8位存在C/G 2种等位基因 ,A组和B组G等位基因频率分别为 19 5 %、10 6 % ,两组间G等位基因频率比较差异有显著性 (P <0 0 5 ) ;(2 )基因型CC、CG、GG的哮喘儿童血浆RANTES浓度分别为 (2 89± 199)ng/L、(5 15± 119)ng/L、(10 71± 138)ng/L ,3种基因型间比较差异有显著性 (P <0 0 1) ;(3)A组血浆总IgE浓度 (以lgIgE表示 )分别为 2 4 5± 0 12、2 77± 0 0 7、3 16± 0 0 9,组间 3种浓度比较差异无显著性 (P >0 0 5 ) ;(4)A组外周血嗜酸粒细胞计数分别为 (2 9± 1 4 )× 10 8/L、(6 4± 0 8)× 10 8/L、(9 9± 2 3)×10 8/L ,组间细胞计数比较差异有显著性 (P <0 0 1)。结论　RANTES启动子 - 2 8C/G基因多态性与儿童过敏性哮喘易感性相关 ,     

开放读码框架50基因介导HIV-1感染相关的肝细胞生长因子诱导人类疱疹病毒8型复制

目的　研究人类疱疹病毒 8型 (HHV 8)开放读码框架 (ORF) 5 0基因启动子在HIV 1感染相关细胞因子肝细胞生长因子 /驱散因子 (HGF/SF)诱导原发性渗出性淋巴瘤 (PEL)BC 3中潜伏感染的HHV 8复制过程中的作用。方法　将HGF/SF连续加入到体外培养的BC 3中 ,分别于培养第 3天和第 7天收集刺激细胞 ,电子显微镜观察成熟HHV 8病毒的形成 ;提取细胞总RNA ,North ernblot和定量聚合酶链反应 (PCR)法检查HHV 8次要衣壳蛋白ORF2 6mRNA转录。同时 ,将已构建的HHV 8ORF5 0启动子 虫荧光素酶报告基因重组质粒和含HIV 1Tat基因重组表达质粒分别共转染BC 3和人脐静脉血管内皮细胞 (HUVECs) ,转染后 2 4h加入HGF/SF和 /或重组HIV 1gp12 0刺激 ,刺激后 2 4h收集细胞 ,进行虫荧光素酶活性检测。试验同时以佛波酯 (TPA)刺激为阳性对照。结果　HGF/SF可以上调HHV 8ORF2 6mRNA表达 ,且于刺激的第 7天 ,ORF2 6mRNA表达上升了 4 .1倍 ,BC 3细胞中同时可观察到成熟的HHV 8病毒粒子 ;HGF/SF能够诱导ORF5 0启动子活性 ,但HIV 1Tat和 gp12 0蛋白与HGF/SF协同上调ORF5 0启动子活性的能力较弱。 结论　HIV 1感染相关细胞因子HGF/SF诱导HHV 8复制的过程至少有部分由ORF5 0启动子介导。     

ADAM33对人肺成纤维细胞增殖、周期、凋亡的影响及IL-4对其表达影响的研究

目的 探讨解整合素-金属蛋白酶33(ADAM33)对人肺成纤维细胞MRC-5增殖、周期、凋亡的影响,以及白介素-4(IL-4)对其表达的影响。方法 分别以1 ng/ml、10 ng/ml、50 ng/ml、100 ng/ml浓度的IL-4刺激MRC-5,以未刺激组细胞为对照,实时荧光定量PCR法检测ADAM33 mRNA的表达情况,Western blotting法检测蛋白表达情况;设计并合成ADAM33-siRNA,瞬时转染MRC-5,MTS法检测增殖情况,流式细胞术检测细胞周期和凋亡。结果 当不同浓度的IL-4刺激MRC-5时,ADAM33 mRNA和蛋白的表达均呈浓度依赖性,1 ng/ml组与0 ng/ml组相比较,差异无统计学意义(P>0.05);10 ng/ml、50ng/ml、100 ng/ml与0 ng/ml组相比较,差异有统计学意义(P<0.05);ADAM33-siRNA明显抑制了ADAM33在MRC-5中的表达;MTS结果显示,在24、48、72 h,干扰组的增殖明显低于阴性对照组,抑制率分别为27.3%、36.6%、19.2%;干扰组S期占的比例(31.69±4.14)%明显低于阴性对照组(47.19±0.99)%(P<0.05);干扰组的细胞凋亡率(28.49±8.79)%明显高于阴性对照组(8.43±5.11)%(P<0.05)。结论 ADAM33可促进人肺成纤维细胞增殖,而细胞因子IL-4可促进其表达,它们可能在气道重塑中起着重要的作用。     

HIV-1 B'/C亚型毒株的复制动力学特点

目的分析不同疾病进展阶段B'/C亚型毒株的复制动力学特点。方法从长期不进展者(long-term nonprogressors,LTNPs)和AIDS期患者体内分离病毒株,用相同量的病毒株去感染正常人的去CD8+T淋巴细胞的外周血单个核细胞,通过检测感染后第0、3、6、9、12、18、21天的上清液中核衣壳蛋白p24(p24)含量,作出折线图来分析该毒株的复制动力学特征。结果从AIDS期患者体内分离的B'/C重组亚型病毒株的复制速度快且p24峰值高,而从LTNPs体内分离的B'/C重组亚型病毒株的复制速度慢且p24峰值低。结论从AIDS期患者体内分离的B'/C重组亚型病毒株复制能力较强,而从LTNPs患者体内分离的B'/C重组亚型病毒株复制能力较弱。     

高糖等因素对系膜细胞细胞周期调节负控蛋白p27的影响

目的　探讨高糖等不同刺激或抑制剂对肾小球系膜细胞膜表达细胞周期负控 p2 7的影响。方法　不同浓度糖 (5.5 mmol/ L和 2 5mmol/ L)、ET1 (1 0 - 7mol/ L)、IL1 3(1 0 ng/ ml、1 0 0 ng/ ml)作用于培养的系膜细胞。流式细胞仪检测系膜细胞 p2 7表达水平。结果　 5.5mmol/ L浓度组在不同时间 p2 7表达为 5.1± 0 .94和 3.84± 0 .81 ,较对照组明显降低 (P<0 .0 0 1 ) ;而 2 5 mmol/ L浓度组在不同时间 p2 7表达为 2 6.82± 3.1 5和30 .88± 3.68,较对照组明显升高 (P<0 .0 1 ,P<0 .0 5)。ET1刺激 1 4 h和 1 8h后 p2 7的表达百分率分别为 1 4 .76± 1 .49和 1 2 .1 8± 1 .30 ,与对照组比较均有明显差异 (P<0 .0 5,P<0 .0 5)。 IL1 3 1 0 ng/ ml浓度组和 IL1 3 1 0 0 ng/ ml浓度组 p2 7表达为 46.74± 3.2 5和 2 3.8± 2 .56,与对照组比较有明显差异 (P<0 .0 0 1 ,P<0 .0 5) ,不同浓度组之间有显著差异 (P<0 .0 1 )。结论　细胞周期调节负控蛋白 p2 7在调节系膜细胞增殖过程中起重要作用     

HIV-1感染、致病机理和人体CCR5、CCR2等基因多态性之间的相互关系研究进展

1 概述 HIV-1感染人体后引起进行性的AIDS病变,通常经历三个典型的时期,第一为急性感染期,表现为广泛的病毒血症;接着是无症状期,此时在淋巴器官中大多可检测出病毒的复制;最后是免疫系统破坏,并伴随病毒血症的再次出现,并产生继发性感染等而死亡。引起AIDS的病毒株有以下几种:(1)嗜巨噬细胞HIV-1株:它主要通过性传播,从初期感染者体内分离到的原代病毒,它感染细胞后不诱生合胞体(syncytia);(2)嗜T细胞HIV-1病毒株:是从发病的AIDS病人身上来源的或实验室培养的毒株。它的毒性很强,感染后,病情呈进行性发展;(3)双嗜性HIV-1病毒株,即感染巨嗜细胞,又感染T细胞。     

HIV-1辅受体的配体在HeLa细胞的表达及其对合胞体形成的抑制

目的 观察HIV—1辅受体的配体、趋化因子RANTES和SDF—1的双顺反子表达载体pCMV—R—K—SK在HeLa细胞系表达，并对其抗HIV—1感染作用进行初步观察。方法 应用PCR扩增RANTES-KDEL基因，鉴定后与真核表达质粒pCMV—S／K连接，构建RANTES和SDF—1双顺反子表达载体pCMV—R—K—S—K，酶切鉴定并测序。脂质体介导转染HeLa细胞，间接免疫荧光及放射免疫沉淀法检测RANTES和SDF—1表达。合胞体形成实验初步检测其抗HIV—1感染的作用。结果 酶切鉴定和测序证明成功构建了pCMV—R—K—S—K双顺反子表达载体，间接免疫荧光及放射免疫沉淀法证实RANTES和SDF—I可以表达于HeLa细胞。pCMV—R—K—SK转染能够抑制M和T嗜性HIV—1膜蛋白诱导的合胞体形成。结论 双顺反子表达载体pCMV—R—K—S—K转染的HeLa细胞可以表达HIV—1辅受体的配体RANTES和SDF—1，并能抵抗HIV—1感染。     

接受抗逆转录病毒治疗的HIV-1/AIDS患者对HIV-1 Vpu的抗体反应

中国台湾省学者发现,HIV 1Vpu蛋白能促进病毒颗粒在细胞外释放和CD4在内皮网状组织降解。作者研究了16 2名HIV 1/AIDS患者在接受高效抗逆转录病毒治疗(HAART) 1年后,研究抗Vpu对Vpu的反应和影响AIDS病情发展的关系。用一重组的Vpu蛋白和Westernblot方法分析抗 Vpu的反应性。结果表明,在开展HAART之前,31 5 %的患者(6 1/ 16 2 )有抗 Vpu。患者的抗Vpu的比例与CD4细胞数有相关关系:CD4细胞数≥5 0 0 /ml,2 0 0 /ml～5 0 0 /ml和<2 0 0 /ml时,抗 Vpu则分别为4 0 6 %、34 7%和14 3%。此外,抗Vpu反应水平下降与HIV 1病毒载量…     

Human recombinant activin-A modulates the steroidogenesis of cultured bovine adrenocortical cells.

The effect of human recombinant activin-A on adrenal steroidogenesis was studied in cultured bovine adrenocortical cells. Activin-A significantly reduced cortisol output from ACTH (10nmol/l)-stimulated adrenocortical cells incubated for 24 hours in a dose-dependent manner (10, 100 and 500ng activin-A/ml suppressed cortisol secretion by 19, 33 and 40%), although no significant effect was observed in the case of 3 h incubation. Dehydroepiandrosterone (DHEA) secretion from ACTH-stimulated adrenocortical cells incubated for 24 h was also decreased by the addition of activin-A in a dose-dependent manner. (10, 100 and 500ng activin-A/ml suppressed DHEA secretion by 22, 56 and 58%). These inhibitory effects of activin-A (100ng/ml) on cortisol and DHEA secretion were partially blocked by the addition of follistatin/FSH-Suppressing Protein (200ng/ml). In contrast, activin-A treatment resulted in no significant decrease in aldosterone secretion. There were no significant effects of activin-A on basal secretions of cortisol, DHEA or aldosterone from adrenocortical cells. These results suggest that activin-A has a direct inhibitory effect on ACTH-stimulated bovine adrenocortical steroidogenesis.     

Increased response of blood eosinophils to various chemotactic agents in quiescent Crohn disease

BACKGROUND: The number of eosinophils is increased in the mucosae of the digestive and the respiratory tracts in Crohn disease, even clinically quiescent. The mechanisms underlying this panmucosal eosinophilia are unknown. METHODS: The response of blood eosinophils to various chemotactic agents was assessed in 15 patients with clinically quiescent Crohn disease. The results were compared with 15 healthy controls. After purification, eosinophils were placed in Boyden microchambers and the chemotactic effect of PAF (10(-7) M), RANTES (50 ng/ml), IL-5 (0-20 ng/ml), IL-8 (0-50 ng/ml), Eotaxin (0-50 ng/ml) was evaluated. The number of eosinophils in induced sputum of these Crohn disease patients and controls was also assessed and the correlation between chemotaxis and eosinophil count in induced sputum was studied. RESULTS: PAF and RANTES induced a chemotactic effect both in Crohn disease patients and controls. The chemotactic index was significantly higher in Crohn than controls for PAF (2.09+/-0.24 versus 1.37+/-0.14; P < 0.05) but not RANTES. With IL-5, IL-8 and Eotaxin, there was no detectable chemotactic effect in controls while in Crohn, we observed a significant dose-dependent chemotactic effect. Furthermore, with Eotaxin 50 ng/ml, the chemotactic index was significantly higher in Crohn disease patients than controls (2.42+/-0.18 versus 1.56+/-0.28; P < 0.05). A significant increase in sputum eosinophil count and a significant decrease in sputum macrophage count in Crohn disease were observed. However, there was no correlation between eosinophil chemotaxis and sputum eosinophil count in individual patients. CONCLUSION: There is an increased response of blood eosinophils to various chemotactic agents, mainly PAF and Eotaxin, in clinically quiescent Crohn disease. This may participate in the mucosal infiltration by eosinophils in this disease.     

Tumor necrosis factor-alpha/cachectin enhances human immunodeficiency virus type 1 replication in primary macrophages

Macrophages are important target cells for human immunodeficiency virus type 1 (HIV-1). The ability of HIV-1 to productively infect macrophages may be influenced by endogenous cytokines that alter the activation state of these cells. In this study, the effect of tumor necrosis factor-alpha/cachectin (TNF alpha), a cytokine with macrophage-activating properties, on HIV-1 replication in primary blood monocyte-derived macrophages was examined. Treatment of macrophages with recombinant human TNF alpha (rTNF alpha), starting before or after HIV-1 infection, consistently enhanced viral production fivefold or greater above control (P less than .01). rTNF alpha was active at low concentrations (0.05-50 ng/ml) and increased the replication of both lymphocyte-tropic (human T lymphotropic virus type IIIB) and macrophage-tropic (human T lymphotropic virus type III BaL) strains of HIV-1. These findings provide additional evidence that TNF alpha may play a role in the pathogenesis of HIV-1 infection by upregulating viral expression in macrophages.     

Vasoactive intestinal peptide stimulates adrenocorticotropin release from human corticotropinoma cells in culture: interaction with arginine vasopressin and hydrocortisone

The effect of vasoactive intestinal peptide (VIP), cholecystokinin octapeptide (CCK), bombesin, arginine vasopressin (AVP), and hydrocortisone (HC) on ACTH release from human corticotropinoma cells in culture has been studied. Tumor tissue was obtained from 6 patients with pituitary corticotropinomas. Eleven to 21 cultures yielding 0.7-2.0 X 10(6) cells/culture, were obtained from each tumor and maintained for periods of 4 weeks to longer than 6 months. VIP (500 ng/ml) significantly (P less than 0.005) stimulated ACTH release from all tumors studied, and a dose (5-500 ng/ml)-response effect was observed in 3 of 5 tumors. Stimulation by VIP was seen at 2,4, and 24 h and was maximal at 4 h. CCK and bombesin were without effect on ACTH release from 4 tumors studies at 4 h. AVP (1-10 mU/ml) stimulated ACTH from 4 tumors studied at 60 min or 4 h. Coincubation of cultures with VIP (50-500 ng/ml) and AVP (1-10 mU/ml) resulted in at least an additive effect. HC (100 ng/ml) significantly (P less than 0.025) inhibited basal ACTH secretion from 2 of 4 tumors at 4 h and from 3 of 4 (P less than 0.005) at 24 h. Simultaneous coincubation of cultures with VIP (50 ng/ml) and HC (100 ng/ml) resulted in an attenuation or blockade of the VIP-stimulated ACTH release, whereas prior incubation of cultures with HC for 28 h before exposure to VIP did not. The results demonstrate that VIP is a potent ACTH secretagogue from human corticotropinoma cells in culture; its effects are additive to those of AVP and modulated by HC.     

The in-vitro effect of tirofiban, glycoprotein IIb/IIIa antagonist, on various responses of porcine blood platelets

The present study systematically evaluates the in-vitro effect of tirofiban, glycoprotein IIb/IIIa (integrins alphaIIbbetaIII) antagonist, on porcine blood platelets. It was found that tirofiban at concentrations up to 5,000 ng/ml did not affect the calcium signal produced by thrombin. Tirofiban, in a concentration-dependent manner reduced platelet aggregation evoked by ADP (IC50 approximately 70 ng/ml), collagen (IC50 approximately 200 ng/ml), and thrombin (IC50 approximately 5,000 ng/ml). Substantial thrombin-evoked platelet aggregation still occurred at high (5,000 ng/ml) tirofiban concentrations. The concentrations of tirofiban completely blocking the optical aggregation evoked by ADP or collagen failed to eliminate microaggregate formation totally. Tirofiban strongly inhibited the dense-granule and lysosome secretion induced by ADP (IC50 approximately 70-170 ng/ml), moderately inhibited that induced by collagen (IC50 approximately 420-500 ng/ml) and very poorly inhibited that elicited by thrombin (IC50 approximately 1,500-5,000 ng/ml). The extent of the inhibition of aggregation and secretion rose as concentrations of the stimulus lowered. Tirofiban was a moderate inhibitor (IC50 approximately 200 ng/ml) of adhesion and a poor inhibitor of platelet procoagulant response induced by collagen. Thromboelastography measurements indicate that, in whole blood, tirofiban, up to concentrations of 2,000 ng/ml, did not affect the kinetics of tissue factor induced clot formation. The obtained results reveal that in porcine platelets, the maximal concentrations of tirofiban used in human medicine (250 ng/ml), effectively block platelet responses triggered by ADP, partly block those induced by collagen and very poorly block those evoked by thrombin. The reason for this phenomenon seems to be the inability of tirofiban to reduce platelet secretion completely.     

Insulin stimulates androgen accumulation in incubations of ovarian stroma obtained from women with hyperandrogenism

The effects of insulin and insulin-like growth factors (IGFs) on ovarian androgen production were examined in ovarian stroma obtained from four women with hyperandrogenism and three women without hyperandrogenism. In incubations of stroma obtained from all four hyperandrogenic patients, insulin alone (500 ng/ml) significantly stimulated androstenedione and testosterone release. LH alone (25 ng/ml) significantly stimulated androstenedione release in incubations of stroma obtained from three of the four hyperandrogenic patients and testosterone release in incubations of stroma obtained from one of the four hyperandrogenic patients. In stromal incubations from three of the four hyperandrogenic patients, insulin alone (500 ng/ml) resulted in a significantly greater release of androstenedione and testosterone than did LH alone (25 ng/ml). Dihydrotestosterone was released in measurable quantities in incubations of stromal tissue obtained from three of the four hyperandrogenic women. In all three instances in which dihydrotestosterone was detectable, insulin alone (500 ng/ml), but not LH alone (25 ng/ml), significantly stimulated dihydrostestosterone release. Incubations of stroma obtained from three nonhyperandrogenic, normally cycling women demonstrated low levels of androstenedione release and negligible testosterone and dihydrotestosterone release. Insulin alone (500 ng/ml) and LH alone (25 ng/ml) produced no significant increase in androstenedione release. Insulin (500 ng/ml) plus LH (25 ng/ml) significantly stimulated androstenedione accumulation in stroma obtained from two of the nonhyperandrogenic women. One insulin dose-response experiment was performed using stromal tissue obtained from a hyperandrogenic woman. In this experiment, insulin, at a dose of 50 ng/ml, was as effective as insulin at a dose of 500 ng/ml in stimulating androstenedione and testosterone release. In addition to insulin, IGF-I/somatomedin C (50 ng/ml) stimulated androstenedione and testosterone release. Relaxin (1 microgram/ml) and multiplication-stimulating activity (50 ng/ml) did not stimulate androstenedione and testosterone release. These studies suggest that human ovarian stroma may be a target tissue for insulin and IGF-I, and that hyperinsulinemia may be an important factor contributing to ovarian hyperandrogenism.     

Mast cell growth factor (c-kit ligand) enhances cytokine stimulation of proliferation of the human factor-dependent cell line, M07e.

Murine mast cell growth factor (muMGF), a c-kit ligand, has additive to greater-than-additive effects on in vitro colony formation of murine and human myeloid progenitor cells stimulated with erythropoietin, granulocyte-macrophage colony-stimulating factor (GM-CSF), and/or interleukin (IL)-3. To confirm direct-acting effects on responding cells, MGF was assessed alone and in combination with other cytokines for effects on the proliferation of the human factor-dependent cell line, M07e. Proliferation was assayed in liquid culture by [3H]thymidine uptake and in semisolid medium by colony formation. Purified recombinant (r) muMGF (25-50 ng/ml) by itself had proliferative activity but less than r human (hu) GM-CSF. In combination with rhuGM-CSF (250 U/ml) or IL-3 (500 U/ml), rmuMGF (25 ng/ml) enhanced [3H]thymidine uptake two- to sevenfold greater than the sum of the effects of each factor alone. Similar enhancement was seen in the number and size of colonies formed. When MGF was used in combination with rhuIL-4 (500-1000 U/ml), rhuIL-6 (5 ng/ml), rhuIL-9 (5-10 U/ml), or rhu interferon gamma (IFN-gamma; 250-500 U/ml) (factors that alone stimulate little proliferation), [3H]thymidine uptake and colony formation were respectively increased 2- to 11- and 3- to 55-fold over the sum of each of the effects of the factors alone. Exposure of 5 x 10(5) cells/ml to 50 ng/ml MGF for 24 h, a time during which synergism is noted with MGF plus either GM-CSF or IL-3, did not change GM-CSF or IL-3 receptor binding affinity or the number of binding sites. Exposure of cells to MGF for 48 h did not alter subsequent GM-CSF- or IL-3-stimulated proliferation. The results suggest that M07e cells will be useful as a model for the analysis of intracellular biochemical mechanisms of the direct-acting proliferative and synergistic effects of MGF.     

Analyses of anti-HIV type 1 activity of a small CCR5 peptide antagonist

We have identified a small peptide (AFDWTFVPSLIL) that specifically binds to CC chemokine receptor 5 (CCR5) expressed on the Chinese hamster ovary (CHO) cell surface. Here, we further investigate its interaction with CCR5 on activated peripheral blood mononuclear cells (PBMCs), and determine whether the peptide inhibits HIV-1 infection mediated by CCR5 in PBMCs. The peptide antagonized the binding of CCR5 ligands, the second extracellular loop-specific monoclonal antibody (mAb) (2D7), regulated on activation of normal expressed and secreted T cells (RANTES), to PBMCs and blocked CCR5-mediated Ca(2+) signaling elicited by RANTES at a concentration of 10 μg/ml. Moreover, the peptide displayed selective inhibition of R5 HIV-1 replication. We conclude that the peptide is a CCR5 antagonist with anti-HIV-1 activity.