化学突变具有底物结合部位的单克隆抗体制备含硒抗体酶

开发了一种制备抗体酶的新方法。用二硝基氯苯（ＤＮＣＢ）专一地与谷胱甘肽（ＧＳＨ）的巯基反应,合成出半抗原ＧＳＨ－Ｓ－ＤＮＰ。用戊二醛将半抗原偶联到牛血清白蛋白（ＢＳＡ）上,制成全抗原。再用标准的单抗制备法获得具有ＧＳＨ结合部位的单抗（４Ａ４ＩｇＧ）。用苯甲基磺酞氟（ＰＭＳＦ）和Ｈ２Ｓｅ相继处理该单抗,则将单拉结合部位上的丝氨酸（Ｓｅｒ）突变成硒代半胱氨酸（ＳｅＣｙｓ,因而在单抗结合部位上引入了谷胱甘肽过氧化物酶（ＧＰＸ）的催化基团。突变后的单抗具有ＧＰＸ活性,其活力已达到天然ＧＰＸ的数量级水平。动力学行为也与天然ＧＰＸ类似。这种新的含硒抗体酶有优于ＧＰＸ的一些特点。     

人结肠癌(CCA)单克隆抗体及其识别抗原的分析(简报)

正常细胞转化成癌细胞后,其表型发生了一系列不同于正常细胞的变化,成为肿瘤细胞的标志。Gold和Freeman(1965)用人结肠癌组织的抽提物免疫兔,发现有些用人正常结肠组织吸收后的抗血清能够与肿瘤组织和胚胎肠道抽提物起反应,但不与正常组织抽提物起反应,由于这种抗原最初被发现在胚胎组织,故名为癌胚抗原(embryonic carcinoma antigen,简称CEA)。用敏感的放射免疫或免疫酶标方     

不同感染状态下EB病毒核抗原亚型表达的研究

本实验用免疫印迹法纯化的抗ＥＢＮＡ亚型抗体,结合显微荧光分光光度检测技术,检测在不同感染状态下,三种亚型ＥＢＮＡ抗原在细胞中的表达程度。结果表明,处于潜伏感染状态下的Ｒａｊｉ细胞ＥＢＮＡ－１表达量较大,经巴豆油和正丁酸诱导进入钝挫感染状态后ＥＢＮＡ－１表达减少,而ＥＢＮＡ－２的表达增强。Ｂ＿（９５－８）细胞也有相似的趋势。表明ＥＢ病毒的激活可能与不同ＥＢＮＡ亚型表达量的改变有关。     

丙肝病毒非结构基因NS_4的基因工程表达

丙肝病毒非结构基因ＮＳ_４的基因工程表达祁自柏,谷金莲,李河民（中国药品生物制品检定所,北京１０００５０）丙肝病毒（ＨＣＶ）基因由结构区和非结构区（ＮＳ１－５）所组成。抗不同病毒蛋白抗体的出现与丙肝发病的关系尚在研究之中。目前,国内丙肝诊断试剂力求包...     

经细菌载体投递的基因融合肽口服免疫对热稳定性大肠杆菌肠毒素的粘膜保护作用

经细菌载体投递的基因融合肽口服免疫对热稳定性大肠杆菌肠毒素的粘膜保护作用肠毒素是大肠杆菌引起腹泻的重要原因。大肠杆菌除了产生分子量较高、热不稳定的肠毒素（ＬＴ）外,还能产生一种分子量较低、热稳定肠毒素（ＳＴ）,因其分子量低,免疫原性也就相对较差,但将...     

细胞培养物中污染支原体的去除

经小鼠体内、体外加用不同的抗菌素处理及克隆的方法处理细胞污染的支原体,三株细胞经两次、一株细胞经三次处理后,经培养法、ＤＮＡ染色法及ＰＣＲ法检查支原体污染均为阴性,并证明对其抗体分泌没有任何影响,不失为一个理想的去除支原体的方法,从而使有重要应用价值的支原体污染细胞的应用成为可能。     

Rat epididymis-specific sperm maturation antigens. I. Evidence that the 26 kD 4E9 antigen found on rat caudal epididymal sperm tail is derived from a protein secreted by the epididymis

Monoclonal antibody 4E9, which was raised against a partially purified detergent extract of rat caudal epididymal sperm, recognizes the tail of sperm from the cauda, but not from caput epididymidis, as well as epithelial cells in a restricted region of the distal caput/corpus epididymidis and proteins in epididymal fluid from corpus and cauda epididymidis. The antigen is apparently a glycoprotein, since it is retained on a Ricinus communis agglutinin l lectin column. Epididymal fluid antigens have apparent M_rS of 38–26 kD, whereas the memrane-associated form of the molecule has an M_r of 26 kD. Immunocytochemical data and Western immunoblot data suggest that the membrane antigen is derived from the fluid antigen, which, in turn, is secrteted by the epididymal epithelium. Characterization of the membrane antigen indicates that it is tightly associated with the sperm surface, behaving as though it is an integral membrane protein. The antigen persists on ejaculated sperm. © 1994 Wiley-Liss, Inc.     

Comparison of the cellular internalization of antibodies used either as immunotoxins or in ADEPT

The internalization into tumor cells of two antibodies (C242 and 454A12), which make potent immunotoxins when linked to ricin A-chain, and an antibody (A5B7), which does not make a potent immunotoxin but has proven useful in ADEPT, was evaluated. The 454A12 antibody was rapidly taken into the cells, 50% of the antibody being internalized after 2 h. The C242 antibody was internalized more slowly, approx 50% being taken up by the cells in 24 h. With A5B7, less than 10% of the antibody was internalized after 24 h. Internalization of the C242 antibody was accompanied by the appearance of antibody degradation products in the cell medium after 2 h, and this degradation could be inhibited by addition of a metabolic inhibitor that prevented cell internalization. In contrast, minimal degradation of the A5B7 antibody could be detected up to 24 h after binding to the cells. In conclusion, both 454A12 and C242 antibodies, which make potent immunotoxins, were internalized into tumor cels. The A5B7 antibody, which does not make a potent immunotoxin, was not internalized, and this property may be one reason why A5B7 has proved useful for delivery of enzymes in ADEPT.     

Antibody raised against extracellular proteinases ofSporothrix schenckii inS. schenkii inoculated hairless mice

Sporothrix schenckii produces two extracellular proteinases, namely proteinase I and II. Proteinase I is a serine proteinase, inhibited by chymostatin, while proteinase II is an aspartic proteinase, inhibited by pepstatin. Studies on substrate specificity and the effect of proteinase inhibitors on cell growth suggest an important role for these proteinases in terms of fungal invasion and growth. There has, however, been no evidence presented demonstrating thatS. schenckii produces 2 extracellular proteinases in vivo. In order to substantiate the in vivo production of proteinases and to attempt a preliminary serodiagnosis of sporotrichosis, serum antibodies against 2 proteinases were assayed usingS. schenckii inoculated hairless mice. Subsequent to an intracutaneous injection ofS. schenckii to the mouse skin, nodules spontaneously formed and disappeared for a period of 4 weeks. Histopathological examination results were in accordance with the microscopic observations. Micro-organisms disappeared during the fourth week. Serum antibody titers against purified proteinases I and II were measured weekly, using enzyme-linked immunosorbent assay (EIA). As a result, the time course of the antibody titers to both proteinases I and II were parallel to that of macroscopic and microscopic observations in an experimental mouse sporotrichosis model. These results suggest thatS. schenckii produces both proteinases I and II in vivo. Moreover, the detection of antibodies against these proteinases can contribute to a serodiagnosis of sporotrichosis.     

Development of chicken intrafusal muscle fibers

The first sign of developing intrafusal fibers in chicken leg muscles appeared on embryonic day (E) 13 when sensory axons contacted undifferentiated myotubes. In sections incubated with monoclonal antibodies against myosin heavy chains (MHC) diverse immunostaining was observed within the developing intrafusal fiber bundle. Large primary intrafusal myotubes immunostained moderately to strongly for embryonic and neonatal MHC, but they were unreactive or reacted only weakly with antibodies against slow MHC. Smaller, secondary intrafusal myotubes reacted only weakly to moderately for embryonic and neonatal MHC, but 1–2 days after their formation they reacted strongly for slow and slow-tonic MHC. In contrast to mammals, slow-tonic MHC was also observed in extrafusal fibers. Intrafusal fibers derived from primary myotubes acquired fast MHC and retained at least a moderate level of embryonic MHC. On the other hand, intrafusal fibers developing from secondary myotubes lost the embryonic and neonatal isoforms prior to hatching and became slow. Based on relative amounts of embryonic, neonatal and slow MHC future fast and slow intrafusal fibers could be first identified at E14. At the polar regions of intrafusal fibers positions of nerve endings and acetylcholinesterase activity were seen to match as early as E16. Approximately equal numbers of slow and fast intrafusal fibers formed prenatally; however, in postnatal muscle spindles fast fibers were usually in the majority, suggesting that some fibers transformed from slow to fast.