4种甲胎蛋白抗原表位肽段致敏树突状细胞诱导细胞毒性T淋巴细胞对肝癌细胞的杀伤效应比较

目的 通过体外杀伤试验,比较4种人肝癌特异性甲胎蛋白抗原表位肽段PLFQVEPV[hAFP(137～145)],FMNKFIYEI[hAFP(158～166)]、GLSPNLNRFL[hAFP(325-334)]和GVAL,QTMKQ[hAFP(542～550)]修饰树突状细胞(DC)后诱导的细胞毒性T淋巴细胞(CTL)对人肝癌细胞的特异性杀伤效应. 方法 选取健康人外周血单个核细胞,体外诱导成熟DC;合成4种hAFP抗原表位肽段分别修饰和诱导DC,体外刺激CTL,通过流式细胞仪法和细胞毒性检测法检测该修饰后的DC所诱导的CTL在体外对肝癌细胞株SMMC-7721细胞的杀伤作用.组间比较应用t检验进行统计学分析. 结果 4种人肝癌特异性甲胎蛋白片段均能在体外修饰和诱导DC细胞的增殖和成熟;这些成熟DC在体外均能诱导特异性CTL,CTL对SMMC-7721细胞均可产生杀伤效应.其中FMNKFIYEI[hAFP(158～166)]肽段诱导的CTL在效靶比分别为80:1、40:1及10:1时对肿瘤细胞的杀伤效应分别达到了78.1%±9.8%、43.9%±5.9%和28.2%±4.9%,比其他3种肽段的杀伤效应高(P<0.05). 结论 短肽段具有单独体外诱导特异CTL的作用,其诱导效果和杀伤效果均优于完整hAFP蛋白,其诱导的CTL有特异地杀伤SMM C-7721细胞的作用.     

4种甲胎蛋白抗原表位肽段致敏树突状细胞诱导细胞毒性T淋巴细胞对肝癌细胞的杀伤效应比较

目的 通过体外杀伤试验,比较4种人肝癌特异性甲胎蛋白抗原表位肽段PLFQVEPV[hAFP(137～145)],FMNKFIYEI[hAFP(158～166)]、GLSPNLNRFL[hAFP(325-334)]和GVAL,QTMKQ[hAFP(542～550)]修饰树突状细胞(DC)后诱导的细胞毒性T淋巴细胞(CTL)对人肝癌细胞的特异性杀伤效应. 方法 选取健康人外周血单个核细胞,体外诱导成熟DC;合成4种hAFP抗原表位肽段分别修饰和诱导DC,体外刺激CTL,通过流式细胞仪法和细胞毒性检测法检测该修饰后的DC所诱导的CTL在体外对肝癌细胞株SMMC-7721细胞的杀伤作用.组间比较应用t检验进行统计学分析. 结果 4种人肝癌特异性甲胎蛋白片段均能在体外修饰和诱导DC细胞的增殖和成熟;这些成熟DC在体外均能诱导特异性CTL,CTL对SMMC-7721细胞均可产生杀伤效应.其中FMNKFIYEI[hAFP(158～166)]肽段诱导的CTL在效靶比分别为80:1、40:1及10:1时对肿瘤细胞的杀伤效应分别达到了78.1%±9.8%、43.9%±5.9%和28.2%±4.9%,比其他3种肽段的杀伤效应高(P<0.05). 结论 短肽段具有单独体外诱导特异CTL的作用,其诱导效果和杀伤效果均优于完整hAFP蛋白,其诱导的CTL有特异地杀伤SMM C-7721细胞的作用.     

树突状细胞致敏的肿瘤疫苗对胰腺癌细胞的杀伤效应

目的:研究胰腺癌细胞冻融物致敏树突状细胞(DC)诱导的细胞毒性T细胞(CTL)对原代培养的自体胰腺癌细胞的杀伤作用．方法:从6例手术切除的胰腺癌组织中分离胰腺癌细胞,反复冻融获得肿瘤抗原;以该肿瘤抗原致敏外周血DC,诱导T细胞转变为CTL;采用Cr51释放法观察CTL对原代培养的自身胰腺癌细胞的杀伤活性,分别以来源于胰腺癌细胞株Pancl的肿瘤抗原致敏DC和未致敏DC刺激的CTL作为抗原对照和阴性对照．结果:实验组CTL对自身细胞的杀伤活性为69．05%±15．79%→88．05%±15．34％,抗原对照组CTL的杀伤活性为43．08％±6．92％→67．30％±8．91％,两组CTL杀伤率均显著高于阴性对照组(P<0．01);而实验组与抗原对照组相比,前者的杀伤活性显著高于后者者(P<0．05)．结论:胰腺癌细胞冻融物致敏的DC疫苗可以诱导T细胞产生高效的针对自体癌细胞的细胞毒效应;新鲜肿瘤组织来源的胰腺癌细胞比传代的Pancl细胞具有更好的抗原性．     

树突状细胞激活的肿瘤浸润性淋巴细胞抗胃癌活性的研究

目的　树突状细胞 (DC)是目前已知的功能最强的抗原提呈细胞 (APC) ,可以向包括肿瘤浸润性淋巴细胞 (TIL)在内的T淋巴细胞提呈抗原 ,并诱发细胞毒T淋巴细胞 (CTL)反应。该文探讨树突状细胞激活的肿瘤浸润性淋巴细胞体外对胃癌细胞 (SGC 790 1 )的杀伤活性。方法　从胃癌患者外周血获取DC ,应用粒 /巨噬细胞集落刺激因子 (GM CSF)、白介素 4(IL 4)和肿瘤抗原激活DC ,然后用DC激活TIL ,观察TIL在体外对自体胃癌细胞和人胃癌细胞株细胞的杀伤活性。结果　DC激活的TIL具有很高的对自体胃癌细胞杀伤活性 ,杀伤率为 (89.39± 3 .0 5) % ,明显高于未经DC激活的TIL、CD激活的T淋巴细胞和未经DC激活的T淋巴细胞对自体胃癌细胞的杀伤率 [杀伤率分别为 (54 .37±1 .50 ) % ,(53 .92± 1 .46) %和 (3 .55± 0 .2 5) % ]。而它们对SGC 790 1细胞的杀伤活性则相对较低。结论　胃癌患者外周血DC能诱导TIL产生高效而特异的抗胃癌免疫     

经树突状细胞递呈的HBcAg特异性细胞毒T淋巴细胞的体外研究

目的　从人的外周血树突状细胞 (DC)的抗原递呈方面研究慢性乙型肝炎的发病机制 ,并诱导出针对HBcAg特异性的细胞毒T淋巴细胞 (CTL)。方法　取健康人DC和患者DC ,比较两组的抗原递呈功能是否存在差异。以HBcAg体外冲击致敏DC ,与自体T淋巴细胞共育 ,诱导出HBcAg特异性CTL ;以HepG2细胞为对照靶细胞 ,转染HBVDNA的HepG2 2 15细胞为靶细胞 ,分别测定CTL在效靶比为 2∶1、6∶1和 2 0∶1时对HepG2细胞的非特异性杀伤率及对HepG2 2 15细胞的特异性杀伤率 ,并比较患者组与正常组特异性杀伤率的差异。结果　患者DC的抗原递呈功能(10 99.2 6 7± 2 39.12 ,1374 .8± 36 4 .15 5 ,2 717.78± 15 89.72 )较健康人 (314 7.933± 72 6 .5 7,384 3.0 0 0±10 6 0 .85 ,5 4 86 .86 7± 1790 .6 4 )弱 ;健康组与患者组CTL对HepG2各效靶比的非特异性杀伤作用差异无显著性。健康组与患者组CTL对HepG2 2 15的特异性杀伤作用差异有显著性 ;患者组CTL的活性 (7.1± 4 .33,15 .6 8± 3.3,2 7.6 6± 4 .5 9)较健康组 (2 0 .76± 6 .0 8,33.97± 8.0 0 ,4 9.6 3± 9.4 8)弱。结论　用HBcAg体外负载患者DC ,能诱导出抗原特异性的CTL ,这些CTL能特异性地杀伤相应靶细胞。     

树突状细胞诱导抗胃癌移植瘤免疫

目的　研究树突状细胞 (DC)体外诱导的抗肿瘤免疫能否抑制裸鼠移植瘤生长并预防其发生。方法　联合应用粒 /巨噬细胞集落刺激因子 (GM -CSF)及白介素 4(IL 4)直接从胃癌患者外周血中培养出DC ;以SGC -790 1细胞的肿瘤抗原粗提物刺激DC使其激活同源的T淋巴细胞产生细胞毒性T淋巴细胞 (CTL) ;建立裸鼠SGC -790 1细胞移植瘤模型 ;DC诱导的CTL治疗裸鼠SGC -790 1细胞移植瘤 ,观察移植瘤生长 ;DC诱导的CTL预防性治疗裸鼠 ,观察随后接种的SGC -790 1细胞移植瘤发生情况。结果　DC诱导的CTL不仅能抑制裸鼠移植瘤生长并能预防其发生。结论　经肿瘤抗原激活的DC作为一新概念上的抗肿瘤疫苗有可能在治疗肿瘤及预防其术后复发和转移中发挥重要作用。     

4种甲胎蛋白抗原表位肽段致敏树突状细胞诱导细胞毒性T淋巴细胞对肝癌细胞的杀伤效应比较

目的 通过体外杀伤试验,比较4种人肝癌特异性甲胎蛋白抗原表位肽段PLFQVEPV[hAFP(137～145)],FMNKFIYEI[hAFP(158～166)]、GLSPNLNRFL[hAFP(325-334)]和GVAL,QTMKQ[hAFP(542～550)]修饰树突状细胞(DC)后诱导的细胞毒性T淋巴细胞(CTL)对人肝癌细胞的特异性杀伤效应. 方法 选取健康人外周血单个核细胞,体外诱导成熟DC;合成4种hAFP抗原表位肽段分别修饰和诱导DC,体外刺激CTL,通过流式细胞仪法和细胞毒性检测法检测该修饰后的DC所诱导的CTL在体外对肝癌细胞株SMMC-7721细胞的杀伤作用.组间比较应用t检验进行统计学分析. 结果 4种人肝癌特异性甲胎蛋白片段均能在体外修饰和诱导DC细胞的增殖和成熟;这些成熟DC在体外均能诱导特异性CTL,CTL对SMMC-7721细胞均可产生杀伤效应.其中FMNKFIYEI[hAFP(158～166)]肽段诱导的CTL在效靶比分别为80:1、40:1及10:1时对肿瘤细胞的杀伤效应分别达到了78.1%±9.8%、43.9%±5.9%和28.2%±4.9%,比其他3种肽段的杀伤效应高(P<0.05). 结论 短肽段具有单独体外诱导特异CTL的作用,其诱导效果和杀伤效果均优于完整hAFP蛋白,其诱导的CTL有特异地杀伤SMM C-7721细胞的作用.     

不同肝癌细胞抗原致敏树突状细胞体外诱导CTL活性的研究

目的比较不同方法提取的肝癌细胞(SMMC-7721)抗原致敏树突状细胞(Dendritic cell DC)后,对特异性细胞毒性T细胞(CTL)的诱导作用。方法分离脐带血单个核细胞,加入重组粒细胞-巨噬细胞集落刺激因子(GM-CSF)和白细胞介素4(IL-4)诱导扩增出脐血DC;SMMC-7721细胞经反复冻融,直接超声破碎及热休克处理后再超声破碎细胞三种方法提取肿瘤抗原,然后分别致敏DC,以MTT法检测脐血DC诱导T细胞增殖及其特异性CTL杀伤活性。结果热休克处理后再超声破碎法提取的抗原致敏DC,能诱导更强的刺激T细胞增殖的能力,并且可以诱导更强的CTL活性。结论加热处理后再超声破碎细胞提取的肿瘤抗原致敏DC,在体外可诱导强大的抗肿瘤免疫保护效应。     

MAGE-3抗原肽致敏树突状细胞的体内抗膀胱癌作用及机制

目的 探讨黑色素瘤-3基因(MAGE-3)抗原肽致敏的树突状细胞(DC)体内对膀胱癌肿瘤的抑制作用及机制.方法 采用Ficoll法从HLA-A2型个体外周血中分离单个核细胞,用GM-CSF和IL-4诱导扩增DC,再经MAGE-3抗原肽致敏,致敏DC细胞和同型T淋巴细胞共培养诱导细胞毒性T淋巴细胞(CTL),经过尾静脉注入膀胱癌荷瘤小鼠,观察其对肿瘤体积及重量的影响.结果 MAGE-3抗原肽致敏的DC诱导产生的CTL可明显缩小瘤体、降低瘤重.结论 MAGE-3九肽致敏DC诱导CTL体内具有抑制膀胱癌细胞增长的作用;其机制可能为激活T淋巴细胞.     

K562冻融抗原负载的树突状细胞诱导抗慢性粒细胞白血病的免疫效应

目的研究K562冻融抗原负载的健康供者来源的树突状细胞(DC)诱导细胞毒性T淋巴细胞(CTL)体外杀伤慢性粒细胞白血病(CML)细胞的毒性效应。方法利用健康供者外周血单个核细胞诱导分化为DC,采用反复冻融法从K562中提取的可溶性相关抗原负载DC;流式细胞学检测负载抗原前后DC表面分子表达的变化;ELISA法检测DC上清中IL-12和IFNγ的含量;混合淋巴细胞反应(MLR)测定DC体外刺激T细胞增殖的能力;乳酸脱氢酶法检测K562冻融抗原负载DC诱导的抗原特异性CTL对CML细胞的杀伤作用。结果与未经抗原负载的DC相比,经K562抗原负载的DC表面分子表达明显上调,CD1a(27·40±5·00)%、(15·40±2·34)%,CD80(61·35±5·35)%、(42·00±2·77)%,CD83(93·30±3·48)%、(25·15±4·02)%,CD86(85·25±4·39)%、(37·25±3·20)%,CD40(89·80±7·18)%、(35·95±4·06)%,HLA-DR(49·50±5·45)%、(17·15±3·61)%,DC分泌IL-12和诱导T细胞分泌IFNγ的能力增加(P<0·05),具有很强的刺激T细胞增殖能力,且刺激强度在24h最强,48h降低,冻融抗原负载DC后激活的CTL在体外对K562的杀伤率为77·35%,显著高于未经抗原负载的DC(P=0·001)。结论经K562细胞冻融抗原负载DC激活的CTL在体外具有更强的增殖能力和杀伤CML细胞的作用。     

消化系恶性肿瘤病人LAK细胞和NK细胞功能与表型的变化

通过观察20例正常人和24例消化系恶性肿瘤病人外周血自然杀伤细胞(NK)和淋巴因子激活的杀伤细胞(LAK)的活性变化,以及加用重组白细胞介素2(rIL-2)刺激前后T淋巴细胞表型变化。结果发现肿瘤病人的NK细胞活性明显下降,但经rIL-2激活后LAK细胞活性得到明显提高,其溶解率接近正常水平。肿瘤病人的总T淋巴细胞(CD_(3+))和辅助/诱导T淋巴细胞(CD_(4+))水平低于正常,但抑制/杀伤淋巴细胞(CD_(8+))水平正常。辅助/诱导淋巴细胞与抑制/杀伤淋巴细胞之比为1.18,低于正常水平(1.55)。经加入rIL-2培养后,CD_(3+)和CD_(8+)淋巴细胞的比率明显升高并达正常水平。而在正常人此变化不明显,且加用rIL-2培养与不加者无显著差异。IL-2受体的表达正常人与肿瘤病人无异。结果显示胃肠道恶性肿瘤病人的免疫机制受到抑制,但能被IL-2提高至正常水平。     

Robust measurement of telomere length in single cells

Measurement of telomere length currently requires a large population of cells, which masks telomere length heterogeneity in single cells, or requires FISH in metaphase arrested cells, posing technical challenges. A practical method for measuring telomere length in single cells has been lacking. We established a simple and robust approach for single-cell telomere length measurement (SCT-pqPCR). We first optimized a multiplex preamplification specific for telomeres and reference genes from individual cells, such that the amplicon provides a consistent ratio (T/R) of telomeres (T) to the reference genes (R) by quantitative PCR (qPCR). The average T/R ratio of multiple single cells corresponded closely to that of a given cell population measured by regular qPCR, and correlated with those of telomere restriction fragments (TRF) and quantitative FISH measurements. Furthermore, SCT-pqPCR detected the telomere length for quiescent cells that are inaccessible by quantitative FISH. The reliability of SCT-pqPCR also was confirmed using sister cells from two cell embryos. Telomere length heterogeneity was identified by SCT-pqPCR among cells of various human and mouse cell types. We found that the T/R values of human fibroblasts at later passages and from old donors were lower and more heterogeneous than those of early passages and from young donors, that cancer cell lines show heterogeneous telomere lengths, that human oocytes and polar bodies have nearly identical telomere lengths, and that the telomere lengths progressively increase from the zygote, two-cell to four-cell embryo. This method will facilitate understanding of telomere heterogeneity and its role in tumorigenesis, aging, and associated diseases.Telomeres are the ribonucleoprotein structures that cap and protect linear chromosome ends from genomic instability and tumorigenesis (1, 2). Intriguingly, telomere shortening protects against tumorigenesis by limiting cell growth (3, 4), but also can impair tissue regenerative capability and cell viability (5, 6).Thus far, most assays of telomere length measure average telomere length from aggregates of many cells derived from dissected tissues, cultured cells, or blood (7). Telomere restriction fragment (TRF) determination (1, 8), a Southern blot-based technique, remains the “gold standard” for determining absolute telomere length, but requires a large amount of starting material (0.5–5 µg DNA) and several days for processing. Moreover, the requirements for gel electrophoresis and hybridization limit the scalability of this assay. Recently, a quantitative PCR (qPCR)-based method for telomere length measurement was developed, providing the convenience and scalability of PCR (9). Although the DNA requirement (35 ng) for qPCR is significantly less than TRF, it still relies on populations of cells to derive sufficient amount of DNA.Quantitative FISH (Q-FISH) allows sensitive visualization of relative telomere length from individual cells and individual telomeres, but this method requires many cells or metaphase arrested cells, which precludes its application to many sample types, including postmitotic cells, senescent cells, and other nondividing cells, and when only one actual cell is required to test. In addition, preparing chromosome spreads requires significant technical skill, and only proliferating cells within a population reach metaphase stage, so this analysis potentially biases the estimates of telomere length for a given cell population (10–12). High-throughput Q-FISH, flow FISH, and single telomere length analysis can be used for telomere measurement of dividing, nondividing, and senescent cells, but these methods also require large cell populations (13–15).The ability to measure telomere length in single cells rather than relying upon average telomere length in cell populations or the entire tissue enables the study of biological heterogeneity on a cell-by-cell basis, an issue of fundamental importance for studies of aging, development, carcinogenesis, and many other diseases. Here, we demonstrate an accurate determination of telomere length in individual cells, with the resolution and scalability of the qPCR telomere length assay.The basis of qPCR is that within a given cell, the ratio of the copy number of telomere repeats to the copy number of a multicopy reference gene is fixed (3), and this method, because of its simplicity, has been widely used to investigate a variety of telomere shortening-associated diseases (7), even sensitive enough to identify mild telomere dysfunction resulting from chronological life stress (16, 17). We adapted qPCR to measure telomere length in individual cells by using a preamplification step that specifically targets both the telomere and multicopy genes, followed by a qPCR assay to obtain telomere to reference gene (T/R) ratio. A single-cell telomere (SCT) length measurement method (SCT-pqPCR) runs robustly, and shows an identical T/R ratio for two sister blastomeres from two-cell–stage mouse embryos. The average result from SCT-qPCR with multiple single cells is linearly correlated to Q-FISH, TRF, and conventional qPCR assays designed for a large number of cells. The heterogeneity of telomere length among several populations of cells by SCT-pqPCR run on multiple single cells is consistent with—and sometimes superior to—results obtained by Q-FISH. Application of SCT-pqPCR to study telomere length during early embryo development, aging, and cancer demonstrate the value of this single-cell telomere length assay method.     

Glycolipid presentation to natural killer T cells differs in an organ-dependent fashion

It has been shown that dendritic cells (DCs) are able to present glycolipids to natural killer (NK) T cells in vivo. However, the essential role of DCs, as well as the role of other cells in glycolipid presentation, is unknown. Here, we show that DCs are the crucial antigen-presenting cells (APCs) for splenic NK T cells, whereas Kupffer cells are the key APCs for hepatic NK T cells. Both cell types stimulate cytokine production by NK T cells within 2 h of glycolipid administration, but only DCs are involved in the systemic, downstream responses to glycolipid administration. More specifically, CD8alpha+ DCs produce IL-12 in response to glycolipid presentation, which stimulates secondary IFN-gamma production by NK cells in different organs. Different APCs participate in glycolipid presentation to NK T cells in vivo but differ in their involvement in the overall glycolipid response.     

Processivity of peptidoglycan synthesis provides a built-in mechanism for the robustness of straight-rod cell morphology

The propagation of cell shape across generations is remarkably robust in most bacteria. Even when deformations are acquired, growing cells progressively recover their original shape once the deforming factors are eliminated. For instance, straight-rod-shaped bacteria grow curved when confined to circular microchambers, but straighten in a growth-dependent fashion when released. Bacterial cell shape is maintained by the peptidoglycan (PG) cell wall, a giant macromolecule of glycan strands that are synthesized by processive enzymes and cross-linked by peptide chains. Changes in cell geometry require modifying the PG and therefore depend directly on the molecular-scale properties of PG structure and synthesis. Using a mathematical model we quantify the straightening of curved Caulobacter crescentus cells after disruption of the cell-curving crescentin structure. We observe that cells straighten at a rate that is about half (57%) the cell growth rate. Next we show that in the absence of other effects there exists a mathematical relationship between the rate of cell straightening and the processivity of PG synthesis—the number of subunits incorporated before termination of synthesis. From the measured rate of cell straightening this relationship predicts processivity values that are in good agreement with our estimates from published data. Finally, we consider the possible role of three other mechanisms in cell straightening. We conclude that regardless of the involvement of other factors, intrinsic properties of PG processivity provide a robust mechanism for cell straightening that is hardwired to the cell wall synthesis machinery.     

Regenerative medicine for the treatment of heart disease

Heart failure is a major cause of mortality worldwide with a steady increase in prevalence. There is currently no available cure beyond orthotopic heart transplantation, which for a number of reasons is an option only for a small fraction of all patients. Considerable hope has therefore been placed on the possibility of treating a failing heart by replacing lost cardiomyocytes, either through transplantation of various types of stem cells or by boosting endogenous regenerative mechanisms in the heart. Here, we review the current status of stem and progenitor cell‐based therapies for heart disease. We discuss the pros and cons of different stem and progenitor cell types that can be considered for transplantation and describe recent advances in the understanding of how cardiomyocytes normally differentiate and how these cells can be generated from more immature cells ex vivo. Finally, we consider the possibility of activation of endogenous stem and progenitor cells to treat heart failure.     

Sickle cell vasoocclusion: heterotypic, multicellular aggregations driven by leukocyte adhesion

Homozygous expression of sickle beta-globin alters the function of blood cells and the endothelium, producing a wide spectrum of clinical manifestations. Intravital microscopy studies in sickle cell mice suggest that vasoocclusion is a complex, sequential, multistep phenomenon involving (1) endothelial activation by sickle erythrocyte (SSRBC), (2) leukocyte (WBC) adhesion to the endothelium, and (3) the direct interaction between SSRBCs and adherent WBCs, which leads to reduced blood flow and tissue ischemia. Each of these steps represents a potentially useful therapeutic target. The identification of molecular determinants mediating vasoocclusion will provide new strategies for the prevention and treatment of this debilitating illness.     

Identification of an inhibitory factor from a Sertoli clonal cell line (TM4) that modulates adult rat Leydig cell steroidogenesis

Sertoli cell produces several biological factors that modulate Leydig cell steroidogenic function by either stimulating or inhibiting its testosterone production. We have evaluated the effect of an inhibitory factor in the spent media of a Sertoli clonal cell line (TM4) which inhibits Leydig cell steroidogenesis. The presence of such an inhibitory factor in TM4 media was bioassayed using Percoll purified Leydig cells isolated from adult rats with purity of greater than 95%. TM4 media inhibited both human chorionic gonadotropin (hCG)-stimulated testosterone and cAMP production by purified Leydig cells dose-dependently but had no apparent effect on 8-bromo-cAMP- and forskolin-stimulated testosterone production. Also it did not interfere with the binding of [¹²⁵I]hCG to Leydig cells. TM4 media inhibited cholera toxin-stimulated testosterone production as well as forskolin- and cholera toxin-stimulated cAMP production. The mechanism of action of this factor in TM4 media appears to be different from transforming growth factor (TGF-β) which inhibited both 8-bromo-cAMP- and forskolin-stimulated testosterone production and inhibited the binding of [¹²⁵I]hCG binding to Leydig cells. The inhibitory factor contained in TM4 media has been partially purified by sequential preparative anion exchange and C-18 reversed-phase high-performance liquid chromatography. In summary, the Sertoli TM4 cell line produces at least one potent inhibitory factor which decreases the responsiveness of purified Leydig cells to hCG stimulation with a dramatically different mechanism from other currently known Leydig cell inhibitory factors; this protein may serve as a valuable tool to study testicular paracrine regulation.     

特应性皮炎的免疫学发病机制

特应性皮炎是慢性复发性炎症性皮肤疾病，发病机制复杂，其中变态反应因素在发病机制中扮演着重要角色。目前认为Th1／Th2平衡失调是特应性皮炎重要的发病机制。本文围绕这一机制综述T细胞、树突状细胞、角质形成细胞及IgE在特应性皮炎发病机制中的作用。     

Micropatterned mammalian cells exhibit phenotype-specific left-right asymmetry

Left-right (LR) asymmetry (handedness, chirality) is a well-conserved biological property of critical importance to normal development. Changes in orientation of the LR axis due to genetic or environmental factors can lead to malformations and disease. While the LR asymmetry of organs and whole organisms has been extensively studied, little is known about the LR asymmetry at cellular and multicellular levels. Here we show that the cultivation of cell populations on micropatterns with defined boundaries reveals intrinsic cell chirality that can be readily determined by image analysis of cell alignment and directional motion. By patterning 11 different types of cells on ring-shaped micropatterns of various sizes, we found that each cell type exhibited definite LR asymmetry (p value down to 10(-185)) that was different between normal and cancer cells of the same type, and not dependent on surface chemistry, protein coating, or the orientation of the gravitational field. Interestingly, drugs interfering with actin but not microtubule function reversed the LR asymmetry in some cell types. Our results show that micropatterned cell populations exhibit phenotype-specific LR asymmetry that is dependent on the functionality of the actin cytoskeleton. We propose that micropatterning could potentially be used as an effective in vitro tool to study the initiation of LR asymmetry in cell populations, to diagnose disease, and to study factors involved with birth defects in laterality.