人端粒酶反转录酶对人胚胎皮质神经元损伤的保护

背景：端粒酶可维持端粒长度,避免细胞复制性衰老和凋亡,其催化亚基端粒酶反转录酶还具有抗凋亡和调节细胞生存的作用。目的：观察人端粒酶反转录酶对β淀粉样蛋白1-40引起的人胚胎皮质神经元损伤的影响。方法：分离和培养12-16周龄人胚胎皮质神经元,将人端粒酶反转录酶基因重组腺病毒转染至神经元。免疫细胞化学法检测人端粒酶反转录酶基的表达,端粒重复序列扩增酶联免疫吸附法检测端粒酶活性。转染后第3天,给予10 μmol/L β淀粉样蛋白1-40作用24 h后,应用MTT检测细胞活力。荧光探针2’ 7’-二乙酰二氯荧光素标记检测细胞内活性氧水平,比色法测定细胞匀浆中谷胱甘肽含量。结果与结论：转染后第3天,人端粒酶反转录酶的表达最高,并重建了其端粒酶活性;10 μmol/L β淀粉样蛋白1-40显著降低神经元的细胞活力和谷胱甘肽的含量(P < 0.05和P < 0.01),升高活性氧水平(P < 0.05)。转染了人端粒酶反转录酶基因的神经元能显著对抗β淀粉样蛋白1-40的毒性作用,增加细胞的活力和谷胱甘肽含量(P < 0.05和P < 0.01),降低活性氧水平(P < 0.05)。结果表明,人端粒酶反转录酶对β淀粉样蛋白1-40引起的人胚胎皮质神经元的损伤有明显保护作用。     

鼠胎肝干细胞生物学特性与人端粒酶反转录酶基因介导的影响

背景：研究表明,感染人端粒酶反转录酶基因后的干细胞具有稳定表达高水平端粒酶活性,且能使细胞增殖旺盛,这为建立基因工程的永生化干细胞系奠定了基础。 目的：探讨人端粒酶反转录酶基因感染对体外培养鼠胎肝干细胞增殖及细胞周期的影响。 方法：体外培养鼠胎肝干细胞,经重组腺相关病毒作为载体介导人端粒酶反转录酶基因感染,用RT-PCR、Western blot检测鼠胎肝干细胞人端粒酶反转录酶基因和蛋白的表达,CCK-8法、细胞生长曲线检测细胞生长增殖情况,流式细胞仪测定细胞周期分布的变化。 结果与结论：与对照组、空载病毒组相比,基因感染组人端粒酶反转录酶基因和蛋白水平均有表达,细胞的生长速度明显增快,G0/G1期细胞减少,S期细胞数增多。结果表明以重组腺相关病毒作为载体介导人端粒酶反转录酶基因感染能促进体外培养的鼠胎肝干细胞增殖,对其培养有优化作用。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

人端粒酶反转录酶转染大鼠许旺细胞的生物学特性

背景：研究表明,基因修饰许旺细胞可使许旺细胞在体内存活时间延长,促进神经再生和功能的恢复。目的：以反转录病毒PLXSN 为载体,将hTERT 基因转染入体外培养的大鼠许旺细胞,检测许旺细胞端粒酶活性及细胞生物学特性。方法：体外培养Wistar大鼠许旺细胞,经反转录病毒PLXSN为载体介导人端粒酶反转录酶基因转染,在同等条件下进行空载病毒转染,以正常培养的许旺细胞为对照组。采用RT-PCR,Western blot检测许旺细胞人端粒酶反转录酶基因和蛋白的表达,流式细胞仪测定细胞周期分布的变化。以细胞生长曲线、MTT比色法观察细胞生长的优化作用。结果与结论：人端粒酶反转录酶基因转染许旺细胞48 h后,检测到人端粒酶反转录酶mRNA和蛋白水平表达明显。与对照组和空载病毒组比较,细胞的生长速度明显增快,G₀/G₁期细胞数减少,S期细胞数增多,差异有显著性意义(P < 0.05)。结果表明通过反转录病毒PLXSN 为载体介导人端粒酶反转录酶基因转染使许旺细胞端粒酶活性明显升高,能够促进体外培养的大鼠许旺细胞增殖。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

人端粒酶反转录酶基因修饰骨髓间充质干细胞调控肝细胞增殖和凋亡

背景：研究表明人端粒酶反转录酶基因的导入可以使骨髓间充质干细胞的生命周期得到显著延长,使其能够继续保持多向分化潜能。 目的：探讨人端粒酶反转录酶基因修饰骨髓间充质干细胞对肝细胞增殖和凋亡的影响。 方法：采取直接贴壁法,分离、培养大鼠骨髓间充质干细胞,利用脂质体转染法,将编码hTERT基因的真核表达质粒pCIneo-hTERT导入骨髓间充质干细胞。将hTERT基因转染骨髓间充质干细胞与肝细胞按1︰1共培养(观察共培养组),同时设未转染骨髓间充质干细胞与肝细胞按1︰1共培养组(对照共培养组)和肝细胞单独培养组,采用MTT比色法和免疫荧光染色法观察骨髓间充质干细胞对肝细胞增殖和凋亡的影响。 结果与结论：观察共培养组的肝细胞增殖率明显高于对照共培养组和肝细胞单独培养组,差异有显著性意义(P < 0.05);观察共培养组的肝细胞存活率明显高于肝细胞单独培养组,差异有显著性意义(P < 0.05)。结果表明人端粒酶反转录酶基因修饰的骨髓间充质干细胞可以抑制肝细胞的凋亡,并促进其增殖,具有改善肝细胞功能的作用。 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

人端粒酶反转录酶基因修饰骨髓间充质干细胞静脉移植治疗糖尿病

背景：胰腺或胰岛细胞移植以及干细胞移植治疗为根治糖尿病带来了希望,但是胰腺或胰岛移植会出现供者缺乏和免疫排异反应问题而限制了其在临床的发展,因此干细胞移植治疗成为目前研究的热点。目的：观察人端粒酶反转录酶基因修饰的骨髓间充质干细胞移植对SD大鼠糖尿病的治疗效果。方法：以反转录病毒PLXSN为载体介导人端粒酶反转录酶基因转染骨髓间充质干细胞。从36只雄性SD大鼠中随机取6只作为对照组,注射生理盐水,其余30只注射链脲霉素(按45 mg/kg)建立糖尿病模型后,随机等分为干细胞组、人端粒酶反转录酶基因转染干细胞组和糖尿病组。造模后干细胞组、人端粒酶反转录酶基因转染干细胞组大鼠通过尾静脉注入1 mL骨髓间充质干细胞(1.5×10¹⁰ L^-1)和1 mL人端粒酶反转录酶基因转染骨髓间充质干细胞(1.5×10¹⁰ L^-1)。结果与结论：注射链脲霉素24 h后,与对照组相比,糖尿病组大鼠空腹血糖明显增加,且高于正常值       (6.7 mmol/L);移植后15 d,与糖尿病组相比,干细胞组、人端粒酶反转录酶基因转染干细胞组大鼠空腹血糖水平显著下降(P < 0.05),体质量显著增加(P < 0.05),人端粒酶反转录酶基因转染干细胞组较干细胞组更为明显;移植后45 d,干细胞组、人端粒酶反转录酶基因转染干细胞组大鼠空腹血糖水平与体质量接近对照组(P > 0.05),人端粒酶反转录酶基因转染干细胞组优于干细胞组,而糖尿病组大鼠空腹血糖维持较高水平,且体质量持续下降。上述结果提示人端粒酶反转录酶基因转染的骨髓间充质干细胞能有效治疗大鼠糖尿病。 中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

构建人端粒酶反转录酶基因腺相关病毒2载体在人髓核细胞的表达

背景：动物研究显示,自体髓核细胞移植能有效修复椎间盘退变。然而髓核细胞体外增殖能力差,这就限制了其作为种子细胞在椎间盘退变性疾病治疗中的研究及应用。 目的：构建包含外源性人端粒酶反转录酶基因的腺相关病毒2载体,观察其转染人髓核细胞后人端粒酶反转录酶基因的表达。 方法：构建pSNAV2.0-pRSV-hTERT质粒并鉴定,采用AAVMaxTM包装系统进行重组腺相关病毒2-人端粒酶反转录酶载体的构建,以PCR及酶切方法验证构建的质粒,构建成功后扩增,并纯化。利用腺相关病毒2-增强型绿色荧光蛋白载体转染第1代人髓核细胞,测定最佳感染复数。参照此感染复数值,确定腺相关病毒2-人端粒酶反转录酶对人髓核细胞转染的相关感染复数;对照组采用不含外源性人端粒酶反转录酶基因的腺相关病毒2进行转染。转染后1,2,4周分别采用RT-PCR对人端粒酶反转录酶基因mRNA水平进行半定量检测。 结果与结论：实验成功构建了腺相关病毒2-人端粒酶反转录酶载体;并获得了滴度达2×10¹¹ v•g/mL的腺相关病毒2-人端粒酶反转录酶载体。测得腺相关病毒2-人端粒酶反转录酶载体对人髓核细胞的最佳感染复数为5×10⁴ v•g/cell。在以1×10⁴,5×10⁴,1×10⁵ v•g/cell转染人髓核后,均可检测到人端粒酶反转录酶基因mRNA的高量表达。采用RT-PCR半定量检测方法,发现以转染后2周时人端粒酶反转录酶 mRNA表达量相对最高(P < 0.05),4周时仍可见人端粒酶反转录酶基因mRNA的稳定表达。而对照组无论在何时间点均未能检测到人端粒酶反转录酶mRNA的表达。提示利用腺相关病毒2可以成功构建包含外源性人端粒酶反转录酶基因的病毒载体,腺相关病毒2-人端粒酶反转录酶能有效转染人髓核细胞并稳定表达人端粒酶反转录酶基因mRNA,此结果可能为增强髓核细胞性能提供新的策略。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

携带端粒酶反转录酶基因siRNA慢病毒载体对星形胶质细胞凋亡的影响

背景：端粒酶反转录酶对端粒酶的激活和活化有重要的作用,利用端粒酶反转录酶的慢病毒载体抑制星形胶质细胞表达对脊髓损伤修复的影响鲜见报道。目的：利用靶向大鼠脊髓源星形胶质细胞端粒酶反转录酶基因的慢病毒载体转染大鼠星形胶质细胞,并观察端粒酶反转录酶基因的慢病毒载体对星形胶质细胞凋亡的影响。方法：原代及传代培养大鼠星形胶质细胞。实验分为端粒酶反转录酶基因siRNA慢病毒载体转染组、单纯慢病毒转染组和空白组,转染后并测其转染率,且在转染后的不同时间段测量大鼠星形胶质细胞的凋亡情况。结果与结论：端粒酶反转录酶基因siRNA慢病毒载体转染组及单纯慢病毒转染组对星形胶质细胞的转染率达85%-90%。免疫荧光染色及流式细胞仪检测显示,端粒酶反转录酶基因siRNA慢病毒载体转染组在转染后24-48 h细胞凋亡率达50%-60%。在单纯慢病毒转染组及空白组细胞凋亡率并无显著改变。结果说明,携带端粒酶反转录酶基因siRNA慢病毒载体可促进大鼠脊髓星形胶质细胞凋亡。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

β-淀粉样蛋白对大鼠海马星形胶质细胞N-甲基-D-天冬氨酸受体亚单位表达的影响

目的 探讨Wistar大鼠海马星形胶质细胞N-甲基-D-天冬氨酸受体（NMDAR）亚单位在β-淀粉样蛋白（Aβ）25~35毒性作用下的表达变化特点。方法 大鼠海马原代培养细胞,加Aβ _25~35（10μmol/L）分别作用1h、24h后,应用免疫荧光方法检测对照组和加药组中NR1、NR2A和NR2B的表达情况（n =10）。 结果 对照组海马星形胶质细胞表达NR1、NR2A和NR2B,阳性点状颗粒主要分布在细胞胞体和突起上,在胞体部位分布密集,在细胞突起则散在分布。经Aβ _25~35作用后,三者表达均显著增强（ P <0．05)。Aβ1h组和24h组相比,NR1无显著变化,NR2A、NR2B的表达随作用时间增加显著增强（　P　<0．05)。结论　正常状态下海马星形胶质细胞可表达NMDAR亚单位（NR1、NR2A和NR2B);Aβ _25~35作用会引起NMDAR各亚单位表达显著增强,NR1的表达变化与NR2A和NR2B的变化表现出不一致性。     

人脐血间充质干细胞移植脑梗死大鼠神经功能的恢复及脑组织端粒酶反转录酶表达

文题释义：人脐血来源间充质干细胞的优势：脐血从孕妇分娩后的胎盘、脐带残端收集，对于产妇和新生儿均没有任何痛苦和不良影响，也不会涉及社会、伦理及法律方面的争论；脐血受胎盘屏障的保护，其成分被病毒、细菌污染的概率低。 端粒酶：细胞中负责端粒延长的一种酶，是基本的核蛋白反转录酶，在保持端粒稳定、基因组完整、细胞长期活性和潜在的继续增殖能力等方面有重要作用。 背景：脐血间充质干细胞可以经体循环有效穿透室管膜进入脑组织，迁移至脑损伤区域并存活分化为神经细胞，作为替代细胞来源用于中枢神经系统疾病的治疗。 目的：探讨人脐血间充质干细胞移植对脑梗死大鼠神经功能恢复及脑组织端粒酶反转录酶表达的影响。 方法：选取130只大鼠为研究对象，随机分为对照组(30只)、模型组(30只)、脐血间充质干细胞1组(35只)、脐血间充质干细胞2组(35只)；对照组不做任何处理，其余各组采用颈内动脉线栓法制作脑梗死大鼠模型，脐血间充质干细胞1，2组于造模成功后1，4 d尾静脉移植2×10⁶个脐血间充质干细胞；移植后24 h检测大鼠血清中活性氧和超氧化物歧化酶水平，移植后第7，14天进行Y-迷宫实验和神经功能评分，采用TUNEL法检测病灶中心神经细胞凋亡率，Western blot法检测梗死灶周围Caspase-3、Bax、Bcl-2、端粒酶反转录酶蛋白表达，RT-PCR法检测梗死灶周围端粒酶反转录酶的mRNA表达。 结果与结论：①与对照组相比，模型组大鼠Y-迷宫实验错误次数、神经功能评分、细胞凋亡指数、Caspase-3、Bax蛋白表达、活性氧水平均显著升高(P < 0.05)，Bcl-2、端粒酶反转录酶蛋白以及mRNA表达、超氧化物歧化酶水平均显著降低(P < 0.05)；②与模型组相比，脐血间充质干细胞1组和脐血间充质干细胞2组大鼠Y-迷宫实验错误次数、神经功能评分、细胞凋亡指数、Caspase-3、Bax蛋白表达、活性氧水平均显著降低(P < 0.05)，Bcl-2、端粒酶反转录酶蛋白以及mRNA表达、超氧化物歧化酶水平均显著升高(P < 0.05)；③与脐血间充质干细胞2组相比，脐血间充质干细胞1组大鼠Y-迷宫实验错误次数、神经功能评分、细胞凋亡指数、Caspase-3、Bax蛋白表达、活性氧水平均显著降低(P < 0.05)，Bcl-2、端粒酶反转录酶蛋白以及mRNA表达、超氧化物歧化酶水平均显著升高(P < 0.05)；④结果表明，脐血间充质干细胞移植可以有效促进脑梗死大鼠神经功能恢复，能够提高脑组织端粒酶反转录酶表达，移植时间越早效果越显著。 ORCID: 0000-0002-4902-1553(余恒) 中国组织工程研究杂志出版内容重点：干细胞；骨髓干细胞；造血干细胞；脂肪干细胞；肿瘤干细胞；胚胎干细胞；脐带脐血干细胞；干细胞诱导；干细胞分化；组织工程     

人端粒酶反转录酶基因修饰脐带间充质干细胞移植治疗急性肾损伤

背景：人端粒酶反转录酶(hTERT)是调控增殖及定向分化的首选生长因子之一,具有多重生物学效应,为建立基因工程的永生化干细胞系奠定了基础。 目的：探讨人端粒酶反转录酶基因修饰脐带间充质干细胞移植对大鼠缺血再灌注诱导的急性肾损伤的治疗作用。 方法：体外培养人脐带间充质干细胞,构建缺血再灌注诱导的大鼠急性肾损伤模型,建模后将大鼠随机分为3组：对照组尾静脉注射1 mL L-DMEM培养液;空载病毒组：尾静脉注射1 mL经空载病毒转染人脐带间充质干细胞悬液;hTERT转染组尾静脉注射1 mL经PLXSN-hTERT转染的人脐带间充质干细胞悬液。 结果与结论：移植后第3,28天苏木精-伊红染色检查示hTERT转染组的肾小管损伤评分<空载病毒组<对照组(P < 0.05)。移植后第28天,CM-Dil 阳性细胞数为hTERT转染组>空载病毒组>对照组(P < 0.05)。移植细胞后第1,3,14,28天血肌酐、尿素氮水平均为hTERT转染组<空载病毒组<对照组(P < 0.05)。结果证实,hTERT基因修饰脐带间充质干细胞移植对大鼠急性肾损伤具有明显的修复作用。  中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

Novel human astroviruses: Novel human diseases?

Astroviruses are small, non-enveloped, single-stranded positive RNA viruses that belong to the Astroviridae family. While classical human astroviruses (HAstV) are a well-recognized cause of acute non-bacterial diarrhea among young children worldwide, novel astroviruses, named HAstV-MLB and HAstV-VA/HMO, have been identified recently in humans by molecular assays. They are phylogenetically more related to animal astroviruses than to classical human astroviruses, thus suggesting cross-species transmission. Serological studies demonstrated a surprisingly high seroprevalence in certain populations and highlighted a high infection rate in the early years of life. Although their pathogenic role has not yet been clearly determined, novel astrovirus RNA sequences have been identified in different biological specimens of symptomatic patients, including the feces, plasma, cerebrospinal fluid, and brain biopsies. Thus, there is evidence that they could contribute not only to digestive tract infection, but also to unexpected clinical syndromes, notably encephalitis and meningitis. Severe infections affect mainly immunocompromised patients. These findings indicate that novel astroviruses should be considered in the differential diagnosis of immunocompromised patients with meningitis or encephalitis of unknown origin.     

Cleavage of human IgM with human lysosomal elastase

Human lysosomal elastase, a serine proteinase stored in the azurophil granules of polymorphonuclear leucocytes, cleaves human monoclonal IgM producing two fragments and dialyzable peptides. An F(ab)₂μ-like fragment, called IgMe in this report, retains some reactivity with an anti-Fcμ-antiserum and is antigenically deficient with respect to both the subunit (IgMs) produced by reduction and alkylation of IgM and the similar fragment (IgMp) produced by papain digestion. The other fragment is very similar to Fabμ generated by papain digestion, as indicated by immunochemical identity and a similar molecular weight.     

Detection of human cytomegalovirus DNA in human tonsillar lymphocytes

The human cytomegalovirus (HCMV) was first isolated in cell cultures from the oropharynx, which is thought to be a site of primary infection. Although HCMV can be recovered from the oropharynx during reactivation phases, its exact site of latency is not known. In the present study we demonstrated evidence suggesting the presence of latent HCMV in this anatomic region--in the palatine tonsils. Samples from 30 tonsils obtained by tonsillectomy were screened for the presence of HCMV. Out of the 30 tonsil donors, 23 were seropositive for HCMV. Three methods were used in attempts to demonstrate HCMV's presence in the tonsils: (1) viral isolation attempts on various cell cultures, (2) immunohistochemical staining--immunoperoxidase method--designed to detect viral antigens, and (3) DNA dot hybridization with a HCMV-DNA probe designed to detect viral DNA. Neither infectious HCMV nor other viruses were isolated in cell cultures. No viral antigens were detected by immunoperoxidase staining in the tonsillar tissue. Four out of the 30 tonsils studied were found to contain viral DNA. In one case in which the tonsillar mononuclear (MN) fraction was separated from the polymorphonuclear (PMN) fraction, only the first fraction contained the viral DNA.     

Infection and maturation of monocyte-derived human dendritic cells by human respiratory syncytial virus, human metapneumovirus, and human parainfluenza virus type 3

Human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV), and human parainfluenza virus type 3 (HPIV3) are common, important respiratory pathogens, but HRSV has a substantially greater impact with regard to acute disease, long-term effects on airway function, and frequency of re-infection. It has been reported to strongly interfere with the functioning of dendritic cells (DC). We compared HRSV to HMPV and HPIV3 with regard to their effects on human monocyte-derived immature DC (IDC). Side-by-side analysis distinguished between common effects versus those specific to individual viruses. The use of GFP-expressing viruses yielded clear identification of robustly infected cells and provided the means to distinguish between direct effects of robust viral gene expression versus bystander effects. All three viruses infected inefficiently based on GFP expression, with considerable donor-to donor-variability. The GFP-negative cells exhibited low, abortive levels of viral RNA synthesis. The three viruses induced low-to-moderate levels of DC maturation and cytokine/chemokine responses, increasing slightly in the order HRSV, HMPV, and HPIV3. Infection at the individual cell level was relatively benign, such that in general GFP-positive cells were neither more nor less able to mature compared to GFP-negative bystanders, and cells were responsive to a secondary treatment with lipopolysaccharide, indicating that the ability to mature was not impaired. However, there was a single exception, namely that HPIV3 down-regulated CD38 expression at the RNA level. Maturation by these viruses was anti-apoptotic. Inefficient infection of IDC and sub-optimal maturation might result in reduced immune responses, but these effects would be common to all three viruses rather than specific to HRSV.     

Immortalization of human keratinocytes with human papilloma virus DNA

Human keratinocytes, derived from the cervix or foreskin, can be immortalized with the HPV-16 or HPV-18 E6 and E7 genes. Two methods of introducing the viral oncogenes into keratinocytes i.e. calcium phosphate transfection and retroviral transduction, are described below, both of which have been optimized for human keratinocytes. While the calcium phosphate transfection method can be used in a normal tissue culture facility, transduction with a retroviral vector containing oncogenes, requires a containment facility and appropriate laboratory practice.     

Uptake of human eosinophil peroxidase by human neutrophils.

A cytochemical analysis was carried out for study of the interaction between human eosinophil peroxidase (EPO) and human neutrophils. To this end, neutrophils with a genetic deficiency of myeloperoxidase (MPO) were used to avoid the otherwise inevitable interference of the high endogenous MPO activity of normal neutrophils. The data show that human neutrophils incubated with EPO (1 GU/ml) rapidly bind the enzyme all over the cell surface and internalize it in small vesicles. Part of bound EPO concentrates in a limited area on the cell surface and is then internalized by means of coarse tubular channels. Fusion of the small vesicles to each other or possibly with the tubular channels gives rise ultimately to EPO-containing multivesicular bodies, which, after 30 minutes of incubation, are the only peroxidase-positive structures in the cytoplasm. Under identical experimental conditions, no binding of human MPO to the neutrophils was detected. At concentrations 10 times as high as those used for EPO, a minority of neutrophils bound MPO, but the binding pattern remained diffuse on the plasma membrane and the internalization was negligible. It seems, therefore, that the EPO trapping system of human neutrophils exhibits specificity at least among leukocyte peroxidases. Furthermore, it operates at much lower concentrations of EPO than those reported for EPO uptake by mast cells and basophils. The uptake of EPO by neutrophils may serve to sequester a potentially toxic agent, thus limiting damage to the tissue in eosinophil-rich inflammatory lesions.     

Blastogenic response of human lymphocytes to human cytomegalovirus.

A method was developed for measuring the blastogenic response of human lymphocytes to human cytomegalovirus (CMV). Viral and control antigens were prepared by extracting disrupted infected and uninfected cell cultures with an alkaline buffer. Lymphocytes from ten donors with complement-fixing (CF) antibody exhibited a blastogenic response, whereas cells from ten seronegative donors did not. A relationship between the stimulation index (SI) and the results of neutralization (NT), indirect haemagglutination (IHA) or CF tests was not observed. The maximum blastogenic response occurred after 5 to 7 days of incubation and was usually greater when the cultures were supplemented with homologous plasma instead of sera. The presence of CMV antibody in the supplementary sera did not appear to affect the reactivity of the lymphocytes.     

Effect of recombinant human interferon γ against human cytomegalovirus

Summary Escherichia coli-derived human interferon- (rIFN-) inhibited the replication of human cytomegalovirus (HCMV) synergistically when combined with IFN-. The induction of HCMV DNA polymerase was inhibited in rIFN--treated cells. It is suggested that the induction of 2–5 A synthetase does not play an important role in the anti-HCMV actions of IFNs.With 2 Figures     

The binding of human IgG subclasses to human monocytes

The direct binding of human IgG subclasses to human monocytes has been measured by autoradiography using radiolabeled myeloma proteins. Only IgGl and IgG3 were found to bind strongly to the monocyte surface. This binding could be inhibited both by fresh human serum and by soluble immune complexes.     

Development of human monoclonal antibodies against human cytomegalovirus.

Human monoclonal antibodies (HMAbs) against human cytomegalovirus (HCMV) have been developed by fusion of human spleen cells and human lymphoblastoid cell lines (NP101 and NP197). The cell line NP101 had great advantages in its high fusion frequency and the stability of the resultant hybridomas. The specificity of HMAbs was confirmed by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence staining. Two of the six HMAbs obtained, which were IgG3 subclass, neutralized viral infectivity in the absence of complement. The neutralizing activity of one of these two HMAbs was enhanced in the presence of human complement, whereas the other was not. Another IgG1 subclass HMAb neutralized viral infection only in the presence of complement. The remaining three HMAbs showed no neutralizing activity. Those HMAbs may provide an important approach to studying human immune responses to HCMV. HMAbs having neutralizing activity may prove to be useful for passive immunotherapy of HCMV diseases.