两种核多角体病毒对中国仓鼠细胞系的感染性

昆虫杆状病毒,尤其是核多角体病毒(NPV)在农林害虫防治上不仅有持续的控制作用,而且有显著的经济效益,已日益受到重视并被开发利用.同时,NPV在使用上的安全性问题亦引起了众多学者的关注.作者曾用NPV对人和猴4个建株细胞作过感染性试验,证实NPV在脊椎动物细胞内是不能复制的(裘卫等,昆虫学研究集刊.6:129,1986).但McIntosh(Intervirology,13:331,1980)曾报道苜蓿丫纹夜蛾NPV(AcNPV)可在中国仓鼠细胞系内复制.为进一步研究NPV在使用上的安全性问题,我们又采用AcNPV和棉铃虫NPV(HaNPV)对中国仓鼠细胞系Dede株(雌成鼠肺组织细胞)进行了感染性试验.     

蓖麻蚕核型多角体病毒DNA转染四种昆虫细胞系的研究

用蓖麻蚕核型多角体病毒(PcrNPV)DNA转染草地贪夜蛾(SF)、家蚕(Bm)、斜纹夜蛾(SL)和菜粉蝶(Pr)四种昆虫细胞系,结果表明,PcrNPV DNA能在SF细胞内复制增殖并形成多角体,Pr细胞系对PcrNPV DNA转染不敏感;Bm和SL细胞出现病变症状,但在电镜下未观察到病毒粒子或多角体。     

八字地老虎血球细胞系的建立

由八字地老虎Xestia c-nigrum血细胞建立了一株细胞系,命名为NEAU-Xc-960716H,原代培养90余天,现已传至70余代。细胞多为圆形,部分梭形,细胞群体倍增时间约为63 h。具有典型的鳞翅目昆虫染色体特征,数量多,形态为短杆状和球形。酯酶同工酶谱为5条主带,与同种昆虫（八字地老虎）的胚胎细胞系(NEAU-Xc-730E)酯酶图谱稍有不同,而与草地夜蛾细胞系(IPLB-SF-21)的酯酶图谱完全不同。该细胞系可以被八字地老虎核型多角体病毒XcNPV感染,但感染率较低。     

家蚕胚胎细胞系Bm-Em-1的建立和特性研究

昆虫细胞系在病毒生物学、 基因功能的研究以及杆状病毒表达系统生产重组蛋白的应用中发挥着重要的作用。本研究由家蚕Bombyx mori “大造”品种反转期胚胎建立了一株细胞系Bm-Em-1, 在含10％胎牛血清的TNM-FH培养基中已传代40余代。显微观察表明, 细胞形态主要为圆形和短梭形, 细胞染色体呈短棒状和颗粒状, 数量多、 异倍化, 符合典型的鳞翅目昆虫细胞染色体特征。RAPD鉴定结果表明, 该细胞系来源于家蚕胚胎, 其扩增谱带与BTI-Tn5B1-4和Sf-9等细胞系明显不同。生长曲线测定结果表明, 第28代细胞的群体倍增时间为82.2 h。病毒敏感性测定显示, 该细胞系不能被苜蓿银纹夜蛾Autographa californica核型多角体病毒（AcMNPV）感染, 但对家蚕核型多角体病毒（BmNPV）高度敏感, 96 h的感染率为91.3％。结果说明该细胞系可作为家蚕病毒离体复制、 BmNPV表达系统以及家蚕基因功能研究的理想材料。     

粘虫核型多角体病毒在同源寄主细胞系内复制的研究

对MsNPV在同源寄主细胞系NEAU Ms 94 7311内复制进行了研究。结果表明 ,接种MsNPV后 72h ,细胞核内开始有成熟的多角体形成 ,病毒接种后 2 4 0h感染率最大 ,达 36.2 % ,至2 64h多角体完全成熟 ,达 2 5.0PIB/感染细胞。病毒增殖曲线表明 ,接毒后 2 4h在培养基中开始检测出MsNPV NOV ,2 4 0h滴度达最大值 ,为 6.32× 10 5TCID50 /mL。病毒连续传代至第 7代或第 8代以后 ,其感染率、病毒滴度及多角体产量均有显著下降。     

苜蓿丫纹夜蛾核型多角体病毒在几株昆虫细胞内增殖的研究

本文对苜蓿丫纹夜蛾核型多角体病毒(Ac NPV)在几个新建昆虫细胞系内的蜡殖过程作了比较。其中SIE—MSH一805、SIE—HAH一806和IPLB—SF一21AF．C细胞在病毒感染96小时后,细胞上清液中的未埋入型病毒(xov)含量可达到高峰;测定TCID,。分别为1．5 x107／ml,1·0。10’／ml和1．0×10‘／tul。病毒感染120小时后,90％以上的细胞形成完整的多角体。据此认为,上述三个细胞系是目前国内较为理想的离体系统,可供用来增殖Ac NPV。     

斜纹夜蛾核多角体病毒抑制苜蓿丫纹夜蛾核多角体病毒诱导的斜纹夜蛾细胞凋亡

野生型苜蓿丫纹夜蛾核多角体病毒(Autographa californica multicapsid nucleopolyhedrovirus, AcMNPV)感染斜纹夜蛾(Spodoptera litura)细胞系Sl-zsu-1,可引起典型的细胞凋亡;但可以在草地夜蛾(Spodoptera frugiperda)细胞Sf-9中复制并形成多角体.比较了AcMNPV p35基因在病毒感染两种细胞的复制和转录情况,认为p35在非受纳细胞中及时有效的表达能阻止细胞发生凋亡;共感染实验结果表明,斜纹夜蛾核多角体病毒(Spodoptera litura multicapsid nucleopolyhedrovirus, SpltMNPV)可以抑制AcMNPV诱导的细胞凋亡并可帮助病毒进行复制,推测SpltMNPV基因组中与p35同源的p49基因挽救了细胞的自杀行为.     

文山松毛虫质型多角体病毒在Sf21细胞中离体增殖试验

研究了文山松毛虫质型多角体病毒(DpCPV-W)在Sf21细胞中的离体增殖行为,并进行了空斑试验,结果显示DpCPV-W毒株能够在Sf21细胞中增殖,也能在Sf21细胞上形成空斑,并能产生形态正常的病毒多角体.在DpCPV-W中加入基因工程增效蛋白,能显著增加病毒粒子对离体细胞的感染率,增幅达145%.生物测定表明,离体增殖的病毒多角体与虫体增殖的多角体的毒力相当.因此,Sf21细胞可以作为文山松毛虫CPV增殖行为研究的离体细胞系统,也可通过空斑纯化技术对文山松毛虫CPV生产防治的病毒种进行单个病毒粒子的分离纯化.     

棉铃虫质型多角体病毒AB两种类型体外复制特性的比较研究

分析比较了棉铃虫质型多角体病毒江苏株Ａ,Ｂ两种类型的离体复制特性,ＨａＣＰＶ－Ａ型病毒可在多种昆早细胞系中复制,而Ｂ型病毒只能在同源细胞系中增殖;Ａ型病毒的感染率和细胞内游离病毒粒子的滴度均高于Ｂ型病毒;感染细胞持续传供表明,ＨａＣＰＶ－Ａ型病毒感染的ＨＡ－８３１细胞在连续传代７次后,感染率从最初的１０．６％上升到８０％以上,反之,Ｂ型病毒的感染的细胞,传供９次后已不能形成典型的多角体。     

家蚕CPV感染离体细胞的电镜观察

本文报道了BmCPV感染家蚕细胞系后的电镜观察。病毒感染早期,细胞质内形成电子致密的病毒发生基质,由病毒发生基质形成BmCPV球状病毒粒子;病毒感染48小时后,多角体在病毒发生基质周围形成,大量的病毒粒子随机包埋在多角体内;病毒接种后96小时,多角体数目增多,其形状有三角,四角,五角及六角形,细胞质内充盈多角体致使细胞核被挤向细胞一侧并伴有形态的改变,受染细胞约为40％。     

A serum-free medium for the culture of insect cells and production of recombinant proteins

Summary A low protein aqueous lipid supplement (Ex-Cyte VLE), in combination with pluronic polyol, is an effective replacement for fetal bovine serum for insect Sf-9 cells. Serum-free medium with lipid supplement and pluronic (SFM-LP) supported higher cell viability and maximum cell populations than serum-supplemented medium. No adaptation procedures are required when switching cells from serum-containing medium to SFM-LP, and growth rates remain constant during continued passages in SFM-LP. The amounts of recombinant proteins produced, which is the major use for the Sf-9 cells, are better or equal in SFM-LP compared to serum-supplemented medium. SFM-LP also supports growth of the TN-368 cell line but IPLB-SF-21AE or IZD-Mb0503 lines grow poorly in this medium.     

Expression of three recombinant proteins using baculovirus vectors in 23 insect cell lines.

Recombinant Autographa california baculoviruses expressing genes for pseudorabies virus glycoprotein (gp50T), human plasminogen (HPg), and beta-galactosidase (beta-gal) were used to infect 23 cell lines or strains. The objectives were to compare amounts of recombinant proteins expressed in the cell lines, compare yields from clones and parent lines, investigate the effects of long-term culture in serum-free medium on production, and determine if some lines yield gp50T with different glycosylation patterns. For HPg, IZD-MB0503 had the highest yield and four other lines (IPLB-TN-R2, IPLB-SF-1254, IPLB-LdEIta, and CM-1) had levels above that of SF-9 cells. For gp50T, four lines (IPLB-HvT1, IPLB-SF21AE, IPLB-SF21AE-15, and IPLB-SF-1254) had higher amounts than SF-9 cells. Some lines yielded gp50T with molecular mass about 1000 daltons larger than that from SF-9 cells, which suggests increased oligosaccharide processing. Equally high levels of beta-gal were expressed in three lines (SF-9, IZD-MB0503, and BCIRL-PX2-HNV3). The major conclusion is that no single cell line produced highest yields for all three recombinant proteins. Four lines were cultured in serum-free medium for 31-34 passages and then infected with the three recombinant viruses. For most cell line-recombinant combinations, the yields in serum-free medium were equal to or better than those in serum-supplemented medium. Medium composition had a much stronger effect on foreign gene expression than on susceptibility of cells to wild-type virus.     

新细胞系──粘虫胚胎细胞系的建立(英文)

一株新细胞系-粘虫（Mythimnaseparata）胚胎细胞系（NEAU－Ms－927311简称Ms937311）被建立。该细胞系多为梭形细胞,少数圆形,贴壁性强。细胞群体倍增时间为58．8h;接种3天后细胞增长速度加快,第5天达到最大值;染色体分析结果表明：染色体聚集成簇,棒球状,呈典型的鳞翅目昆虫细胞核型;酯酶同工酶分析有两条明显的谱带;该细胞系可被同源核型多角体病毒（MsNPV）侵染并形成多角体。     

NEW CELL LINE FROM EMBRYOS OF MYTHIMNA SEPARATA (LEPIDOPTERA: NOCTUIDAE)

Abstract  A new cell line was established from 2-d-old embryonated eggs of Mythimna separata and has been designated as NEAU-Ms-927311. This cell line consists of a mixture of cell types, including spherical and spindle-shaped cells. The cell line has a population doubling time of 58. 8h. Chromosome analysis revealed its typical lepidopteran karyology. Isozyme characterization of esterase showed that the band pattern was different from that of other two cell lines (Xc-920730, and SF-21AE). Virus infectivity tests revealed this cell line can support replication of M. separata nuclear polyhedrosis virus.     

Influence of cell- and media-derived factors on the integrity of a human monoclonal antibody after secretion into serum-free cell culture supernatants

To investigate the effects of factors secreted by different cell lines on human monoclonal antibody (MAb) integrity, 600 mg of a human MAb, which specifically binds to human erythrocytes, were produced in a perfusion process. After purification by protein A affinity chromatography, the MAb was used for integrity testing in supernatants of several cell lines to investigate their potential to degrade the antibody in the extracellular environment. One insect cell line (IPLB-SF-21 AE) and four mammalian cell lines [CHO K1, BHK-21 (C13), C1271, P3-X63-Ag8.653], all of them commonly used for the production of recombinant proteins, and the human-human-mouse heterohybridoma cell line itself (H-CB-hahE), were adapted to serum-free culture media. For integrity testing all cell lines were cultivated in spinner flasks using serum-free media supplemented with 30 mug mL(-1) of purified MAb. MAb integrity was assayed by SDS polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing, both followed by Western blotting, and an antigen binding assay. None of the mammalian cells showed any detectable effects on antibody stability and integrity during exponential growth, whereas isoelectric focusing of monoclonal antibody taken from IPLB-SF-21 AE culture supernatants revealed a new band indicating a partial modification of the MAb by secreted factors of these cells. This observation did not correlate with the total proteolytic activity, which was measured in all supernatants and found to be lowest in the insest cell cultures. For mammalian cell cultures, it could be concluded from these findings that shifts of the antibody microheterogeneity pattern, which can be found normally as a result of variations in different production parameters, are not caused by extracellular factors once the product has been secreted into the supernatant. In addition to their well-known advantages in posttranslational modifications (e.g., formation of complex type N-glycans), mammalian cells appear to be more suitable as expression systems for human monoclonal antibodies to be used in vivo when compared with baculovirus-infected insect cells. (c) 1995 John Wiley & Sons, Inc.     

Use of commercial serum replacements for the culture of insect cells

Summary Two commercially available serum replacements developed for use in the culture of hybridoma and other mammalian cells were tested for their suitability as replacements for fetal bovine serum in insect cell culture medium. CPSR-1 and CPSR-3 both supported growth of the insect cell line IPLB-SF-21AE. CPSR-3 supported adequate growth, but cells in medium supplemented with CPSR-1 grew much slower and achieved only about half the final cell density of either FBS or CPSR-3 supplemented medium. This work was supported in part by grant 187159 from the Juvenile Diabetes Foundation and BRSG RR05876 from the National Institutes of Health, Bethesda, MD.     

Generation and analysis of defective genomes of Autographa californica nuclear polyhedrosis virus.

We have generated defective genomes of Autographa californica nuclear polyhedrosis virus (AcNPV) by serial, undiluted passage in IPLB-SF-21 cell culture in an attempt to identify potential cis-acting sequences important for AcNPV DNA replication. Viral DNA isolated from some of the 81 serial passages was analyzed by pulsed-field gel electrophoresis, restriction endonuclease analysis, and Southern blot hybridization. AcNPV-defective genomes appeared to be generated through a series of successively smaller and transiently stable intermediates. Although the defective genomes at passages later than passage 65 (P65) were somewhat heterogeneous in size, those of the majority of the population had a mean size estimated to be 50 kb, or 40% of that of standard virus. Defective genomic DNA at P81 hybridized strongly only to a 2.8-kb region mapping within 85.0 to 87.2 map units of AcNPV DNA (most of HindIII-K and a small part of HindIII-B), suggesting that the majority of P81-defective genomes were missing most of the 128-kb wild-type DNA sequence, except for this small 2.8-kb fragment. Furthermore, our results indicated that the defective genomes of P81 were composed largely of reiterations of this sequence. We suggest that the 2.8-kb DNA segment retained by the defective AcNPV genomes of P81 contains an important cis-acting element(s) sufficient for viral DNA replication in AcNPV-infected cells.     

Virulence and Pathogenesis of Yellow Fever Virus Serially Passaged in Cell Culture

Viscerotropic virulence of the Asibi strain of yellow fever virus (YFV) for monkeys has been known to be lost after serial passage in HeLa cell monolayers. This phenomenon was investigated in several other mammalian and insect tissue cell lines. Assay in monkeys of original seed virus and of virus after 7 and 11 passages in a porcine kidney cell line (PK) indicated essentially equal infectivity and mortality. Moreover, monkeys receiving the passaged virus exhibited more rapid onset of disease and death than animals infected with original seed virus. Histological changes in animals inoculated with passaged virus were identical to those in animals receiving the seed virus. Virus from later passages in PK cells was also lethal for approximately 50% of the monkeys; however, evidence for progressive attenuation was seen in these preparations. Similar results were obtained with a mosquito (Aedes aegypti) cell line. In contrast to results obtained in PK and mosquito cells, YFV became essentially avirulent (nonlethal and less infective) for monkeys after only seven passages in HeLa cell cultures.