肿瘤睾丸抗原CTA的研究进展——基因表达的活化与精子发生

就目前关于CTA基因的表达、功能、调节、CT抗原的免疫原性做一综述，分析了最新的关于CTA基因活化的假说．该假说从进化论的思想角度着手，认为CTA基因的活化与早期生命系统发育中的染色体倍数性循环有关，所以与精子发生相联系．该假说的提出可以拓宽目前抗肿瘤研究的思路．     

Morphogenesis of human colon cancer cells with fetal rat mesenchymes in organ culture

Summary The morphogenesis and cytodifferentiation of human colon cancer cells (LS174T and HT29) were examined by combining cancer cells with fetal rat digestive-tract mesenchyme in organ culture. LS174T cells migrated into the mesenchyme to form glandular structures composed of single columnar cells with their nuclei oriented basally, while HT29 cells formed cell masses with little lumen formation. Immunohistochemical studies with antibodies against carcinoembryonic antigen and secretory components showed that the composition of cell surface glycoproteins was not necessarily reversed to the normal type, even when neoplastic cells exhibited normal glandular structures.This work was supported by grants-in-aid for Cancer Research from the Ministry of Education, Science, and Culture, Japan, and by the Veterans Administration Medical Research Service, USA. Y.S. Kim is the recipient of a Medical Investigator Award of the Veterans Administration.     

Mechanisms of glial-guided neuronal migration in vitro and in vivo

Summary Our laboratory has developed an in vitro model system in which glial-guided neuronal migration can be observed in real time. Cerebellar granule neurons migrate on astroglial fibers by apposing their cell soma against the glial arm, forming a specialized migration junction, and extending a motile leading process in the direction of migration. In vitro assays indicate that the neuronal antigen astrotactin functions as a neuron-glia ligand, and is likely to play a role in the movement of neurons along glial fibers. In heterotypic recombinations of neurons and glia from mouse cerebellum and rat hippocampus, neurons migrate on heterotypic glial processes with a cytology, speed and mode of movement identical to that of neuronal migration on homotypic glial fibers, suggesting that glial fibers provide a permissive pathway for neuronal migration in developing brain. In vivo analyses of developing cerebellum demonstrate a close coordination of afferent axon ingrowth relative to target cell migration. These studies indicate that climbing fibers contact immature Purkinje neurons during the migration and settling of Purkinje cells, implicating a role for afferents in the termination of migration.     

Expression of hepatitis B surface antigen gene (HBsAg) in Laminaria japonica (Laminariales, Phaeophyta)

A transformation model for Laminaria japonica was established from 1993 to 1998, on the basis of which the transgenic kelp with heterologous gene encoding hepatitis B surface antigen (HBsAg) was obtained by using the microparticle bombardment transformation method. Results of quantitative ELISA showed that HBsAg in transgenic kelp was 0.529 μg/mg soluble proteins on average and the highest value was 2.497 μg/mg, implying that recombinant HBsAg had natural epitope. Further support for the integration of HBsAg gene into kelp genome was obtained by PCR-Southern and total DNA hybridization. Prospect of kelp bioreactor producing high value materials such as edible HBV vaccine was discussed as well.     

基于PSS/PAH包被的AuNRs免疫传感器用于CEA的测定

通过聚苯乙烯磺酸钠(PSS)与聚丙烯氯化铵(PAH)以层层堆积(LBL)的形式包被到金纳米棒(AuNRs)的表面,从而替换AuNRs表面具有生物毒性的十六烷基三甲基溴化铵(CTAB).将癌胚抗原(CEA)的抗体(Ab)交联到AuNRs的表面,研制出一种新的癌胚抗原(CEA)的检测方法.随着CEA与AuNRs表面的Ab发生特异性反应,使AuNRs发生自组装,从而导致其紫外可见吸收光谱发生变化.通过测量吸收光谱的变化可以实现CEA的定量检测.采用电化学交流阻抗法和循环伏安法考察了不同修饰层结合到AuNRs表面后的变化情况;考察了溶液pH、Ab与CEA的结合时间对响应的影响.在最优条件下,该传感器的检测范围为10~100ng/mL,检测下限为3.3ng/mL.     

HBV/HEV二价疫苗性抗原基因在E.coli中表达条件优化的初步研究

为有效提高由乙型肝炎的S抗原基因和戊型肝炎ORF2编码区羧基末端414-606氨基酸基因片段构建的高效表达载体质粒PTΩ-T7SE在大肠杆菌BL21(DE3)中的表达效率,研究了质粒稳定性、葡萄糖质量分数、pH值、IPTG浓度、转接量、诱导时间、诱导温度、溶解氧对目的蛋白相对产量的影响,优化得到了较好的培养方法,使目的蛋白的相对含量达48.23%,菌体干重达0.596 3 g/L.结果表明,采用优化方法可制备较高纯度蛋白.本研究为大规模的发酵工艺提供了依据.     

仙台病毒抗原的制备及初步应用

目的纯化和制备仙台病毒(Sendai Virus,SeV)抗原,初步应用于间接酶联免疫吸附试验(ELISA)及免疫印迹(Western-blot)试验对SeV抗体进行检测。方法通过鸡胚尿囊腔及BHK-21细胞增殖法培养增殖SeV,低温冻融去除细胞碎片后,用差速离心及超声破碎法纯化并制备SeV抗原,以SDS-PAGE电泳进行纯度鉴定;优化确定间接SeV-ELISA抗原的最佳包被浓度,对比检测间接免疫荧光试验(IFA)初筛小鼠SeV阳性血清,同时用Western-blot检测法进行特异性验证。结果用BHK-21细胞培养增殖的SeV,病毒滴度HA为1∶128,SeV抗原的电泳纯度达80%;确定SeV-ELISA抗原最佳包被浓度为2.5μg/mL时,测得小鼠SeV抗体ELISA与IFA的阳性符合率为100%,并由Western-blot检测法得到了证实。结论通过BHK-21细胞增殖和差速离心及超声破碎法制备的SeV抗原,可用于ELISA及Western-blot法对小鼠SeV抗体的检测,进而验证了SeV具有较强的抗原特异性及蛋白活性。     

基于免泵微流控芯片和电化学检测的便携式生物医学传感器研究

为满足即时检验(point-of-care testing,POCT)在基层和个性化诊疗使用需求,开发了一种免泵式微流控芯片和电化学检测生物医学传感器系统,配合免疫传感器完成了对过氧化氢和前列腺癌标志物的快速检测。系统利用改性处理后聚二甲基硅氧烷芯片通道内毛细作用力,自泵式完成待测试剂混合和流动,采用微型便携式检测设备控制输入信号并通过微电流检测电路设计读取传感器上电流信号,实现快速自动化检测。实验验证了三电极检测电路输出电位稳定,误差不超过1%;通过对双氧水浓度检测实验证明了该检测体系对浓度变化电流动态响应特性良好,输出稳定;检测系统配合生物传感器对前列腺特异性抗原浓度进行定量检测,检测限为1 ng/m L。据我们所知,这是首次利用电化学免泵微流控传感器进行前列腺抗原的检测,本体系结构简单,操作简便,系统有望与多种电化学传感器结合用于多种检测物质的快速智能化POCT检测。     

Legionella pneumophila down-regulates MHC class I expression of human monocytic host cells and thereby inhibits T cell activation

Legionella (L.) pneumophila, the causative agent of Legionnaires disease, is an intracellular pathogen of alveolar macrophages that resides in a compartment displaying features of endoplasmatic reticulum (ER). In this study, we show that intracellular multiplication of L. pneumophila results in a remarkable decrease in MHC class I expression by the infected monocytes. During intracellular multiplication, L. pneumophila absorbs ER-resident chaperons such as calnexin and BiP, molecules that are required for the correct formation of the MHC class I complex. Due to reduced MHC class I expression, stimulation of allogeneic blood mononuclear cells was severely inhibited by infected host cells but cytotoxicity of autologous natural killer cells against Legionella-infected monocytes was not enhanced. Thus, reduced expression of MHC class I in infected monocytes may resemble a new immune escape mechanism induced by L. pneumophila.Received 22 November 2004; received after revision 27 December 2004; accepted 5 January 2005     

抗原处理相关转运体( TAP) 的结构和功能研究进展

摘要: 抗原处理相关转运体( TAP) 属于 ABC( ATP-binding cassette) 转运体超家族的 B 亚家族,是由主要组织相容性 复合体( Major histocompatibility complex ,MHC) 上 2 个紧密连锁的基因 TAP1 和 TAP2 编码蛋白组成的异二聚体,位 于内质网和顺式高尔基膜上,功能是将抗原肽从细胞质转运进入内质网池,组装到 MHC I 类分子上构成复合体。 TAP 蛋白的缺乏和突变会影响抗原肽的提呈,最终损害免疫应答功能。