影响猪繁殖与呼吸综合征病毒感染与增殖的因素

猪繁殖与呼吸综合征病毒(PRRSV)感染宿主细胞以及在宿主细胞内进行复制的过程受到宿主细胞的细胞受体、胞内大分子及细胞因子影响。随着单克隆抗体制备技术、分子生物学技术与蛋白质研究技术的日趋成熟,使深入研究影响PRRSV感染与增殖的因素成为可能。目前在猪肺巨噬细胞(PAM)与Marc-145细胞中发现了多个PRRSV细胞受体,这与PRRSV感染宿主细胞所具有严格的细胞嗜性有关。同时胞内大分子物质可导致PRRSV在宿主细胞内产生增殖性感染。包括干扰素在内的细胞因子具有抑制PRRSV在宿主细胞内增殖的作用。研究影响PRRSV感染与增殖的因素,对于预防PRRSV感染与合理利用PRRSV具有重要意义。     

3种受体抑制剂对鸡传染性支气管炎病毒感染鸡胚肾细胞的影响

本研究旨在阐明鸡氨肽酶N(chAPN)、唾液酸以及硫酸乙酰肝素在传染性支气管炎病毒(IBV)M41株感染宿主细胞中的作用以及3种受体特异抑制剂对IBV M41株在自然宿主CEK细胞内增殖能力的影响.作者选择苯丁抑制素(Bestatin)、神经氨酸酶(NA)和肝素酶Ⅲ分别作为APN、唾液酸以及硫酸乙酰肝素的抑制剂,在不同条件下,单独或共同预处理CEK细胞,而后接入IBV M41株病毒感染细胞,应用荧光定量PCR方法定量检测IBVM41株在CEK细胞中的增殖变化,应用鸡胚半数感染剂量法(EID50)测定病毒感染鸡胚能力的变化.结果表明,经Bestatin和NA处理的CEK细胞获得了抵抗IBV M41株感染的能力,与未经处理的(对照组)细胞相比,Bestatin和NA能显著降低IBV M41株在CEK细胞内的增殖及对鸡胚的感染能力(P＜0.01),且Bestatin处理后CEK细胞内的病毒增殖量显著低于NA处理后CEK细胞内的病毒增殖量,两者病毒液的EID50滴定值差异显著(P＜0.01);肝素酶Ⅲ的处理则对病毒增殖无显著影响;3种受体抑制剂共同处理CEK细胞后,病毒增殖量显著下降(P＜0.01),但仍有病毒增殖,病毒液的EID50滴定值为102.12±0.05·0.1 mL-1.结果提示,chAPN在IBV感染宿主细胞的过程中发挥特异性受体作用,而唾液酸在IBV感染宿主细胞中发挥辅助受体作用,硫酸乙酰肝素不是IBV在自然感染中的必需因素,同时提示,可能存在其他未知受体因子参与IBV感染宿主细胞的过程.     

猪瘟病毒入侵机制研究：MERTK促进猪瘟病毒的内化

正病毒不能在细胞外增殖,只有侵入到宿主细胞后利用宿主代谢系统完成自身的复制周期。病毒与细胞受体或入侵因子相互作用是病毒感染宿主的重要起始环节。猪瘟(Classical swine fever)是由猪瘟病毒(Classical swine fever virus, CSFV)引起的一种猪的急性、烈性传染病,在多个国家和地区流行,给全球     

动物病毒细胞增殖的研究进展

从宿主细胞的选择、连续传代、培养条件、添加病毒保护剂、改变细胞基因结构等方面对促进病毒感染细胞的方法进行概述,为病毒在细胞上的增殖研究提供参考。     

猫杯状病毒蛋白酶-聚合酶新功能：宿主mRNA降解的“剪刀”

正猫杯状病毒(Feline Calicivirus, FCV)是猫和其它猫科动物的重要病原体,属于杯状病毒科水疮性病毒属成员,也是该科成员中少有的能够在细胞进行培养的病毒,是研究杯状病毒科生物学特性的重要模型。FCV能够"突破"宿主的各种抗病毒应答,在体内外进行快速增殖,病毒是通过什么途径来完成快速复制并且不被宿主所"识别"呢?病毒和宿主相互作用中一个很重要的主题是限制对方的基因表达。病毒在感染细胞的过程中,基因组会快速复制,同时会利用宿主细胞大量合成自身蛋白,这会占用宿主细胞很多资源,为了更好利用细胞的合成     

养猪业病毒性疾病的防控

1 流行现状流行 病毒种类增加,原有病毒的毒力不断增强。病毒在演化过程中,会不断调整自身对宿主细胞的适应性,以应对外界环境的变化,在增殖过程中会出现碱基配对错误而产生变异,可能导致病毒的毒力增强。     

犬细小病毒宿主范围和入侵途径研究进展

犬细小病毒(Canine parvovirus,CPV)引起的犬细小病毒病是犬科动物的主要传染病,病毒在进化过程中出现了多个不同的分型,这些分型对细胞和组织嗜性及宿主范围都是由病毒的分子生物学特点所决定,本文综述了犬细小病毒细胞嗜性及宿主范围的分子特点和病毒的入侵途径,为细小病毒的控制提供基础。     

禽疱疹病毒Ⅰ型与宿主互作研究新视角:锁定病毒感染微环境中的非感染宿主细胞

正细胞凋亡被普遍认为是宿主抵御病原微生物感染的一种先天防御机制。宿主通过启动被感染细胞程序性死亡直接限制病毒在体内的增殖和扩散。这一认知主要是基于大量体外研究获得的。这些研究普遍采用高感染复数的病毒接种细胞以保证试验系统内几乎所有细胞均被病毒感染。然而,体内病毒感染微环境十分复杂,包括病毒、病毒感染细胞及其周边大量未感染病毒的细胞。近年来陆续有研究     

家蚕病毒病的综合防治措施

<正> 家蚕病毒是超显微的、没有细胞结构的、特定的活细胞寄生的大分子微生物,他们在活体外具一般大分子特征,即具有潜在浸染力的病毒粒子(如病毒包含体BmFV和BmDNV、多角体BmCPV和BmNPV等),一但进入宿主细胞,就具有极强的生命特征,其病毒核酸的遗传活性附加于或取代其宿主细胞核酸的遗传活性,打破细胞的自身规律进行过剩的增殖,使被侵袭的细胞机能低下而出现病害。病毒是专性细胞内寄生物,只能在活细胞内繁殖,感染细胞后接管宿主细胞     

家蚕核型多角体病毒的离体增殖

<正> 关于家蚕(Bombyx mori)核型多角体病毒(BmNPV)已是研究较为深入的一种杆状病毒。家蚕细胞系统是研究病毒与宿主相互关系,病毒的特异性,病毒基因表达的理想实验材料。最令人感兴趣的是:这一材料已发展成为表达外源基因的载体宿主系统。目前国内正积极利用该材料,从事各种研究。系统地研究BmNPV在离体细胞中的复制增殖,特别是在较大规模培养细胞水平探索病毒增殖规律方面,对于进一步开发应用这一病毒资源,拓宽其应用价值是十分重要的。本文在静止培养70毫升细胞规模下,研究了BmNPV的离体增殖及其特征。     

Genetic comparison of ovine and bovine pestiviruses

Viral RNA oligonucleotide fingerprinting was used to compare genetic relationship among pestiviruses originating from ovine or bovine host species. Ovine pestiviruses, including reference border disease virus and 2 border disease isolates originating from natural pestivirus infections of sheep, appeared to have a more distant genetic relationship among themselves than with certain bovine pestiviruses. A closer genetic relatedness was evident between border disease virus and 3 noncytopathic bovine pestiviruses, including Draper bovine viral diarrhea virus (BVDV), a BVDV isolate that originated from aborted bovine fetuses, and a virus that was isolated from the serum of a calf that had a chronic BVDV infection. Four noncytopathic bovine viruses, including Draper BVDV and 3 field isolates, were closely related. Reference Oregon C24V BVDV, a cytopathic virus, was closely related to only 1 of the 7 noncytopathic viruses in this study.     

Molecular genetics of pestiviruses.

Recent developments in understanding the molecular genetics of pestiviruses are reviewed. The genomic RNA of several pestiviruses has been molecularly cloned and sequenced. The genetic organization of the viral protein coding region has been refined, and the complete complement of virus-encoded proteins has been elucidated. Viral gene expression involves both co-translational and post-translational precursor polyprotein processing. Biogenesis of the virion structural proteins requires the proteolytic activity of the first protein of the open reading frame (p20), as well as host cell enzymes. A second virus-encoded proteinase (p80) is required for processing viral nonstructural proteins. Molecular and biochemical data indicate pestiviruses share many features with both the flaviviruses and human hepatitis C viruses, while at the same time, also reveal their distinct nature.     

A serological investigation of pestiviruses in sheep in eastern border of Turkey

All pestiviruses are important veterinary pathogens causing economic losses in cattle, sheep, and pigs. In this study, blood samples randomly collected from 465 sheep were analysed for the presence of antibodies to pestiviruses (bovine viral diarrhea virus, border disease virus) using an enzyme-linked immunosorbent assay in the province of Van and their towns. The seroprevalance were estimated as 75.9% and 60.0–82.5% in the sampled animals and sampled towns, respectively. The results revealed that pestiviruses are important abort pathogens in the province of Van and their towns.     

Experimental infection of cattle, sheep and pigs with 'Hobi'-like pestivirus

To date, limited information is available on the ability of 'Hobi'-like pestiviruses (putative bovine viral diarrhoea 3) to infect and cause disease in animal species traditionally affected by pestiviruses. In order to obtain new insights into host range and pathogenic potential of this atypical pestivirus, BVDV-seronegative calves (n=5), lambs (n=5) and piglets (n=5) were experimentally infected with the European 'Hobi'-like strain Italy-1/10-1, whereas two animals per species served as uninfected controls. Appearance of clinical signs, leukopenia, viremia, viral shedding and seroconversion were monitored for 28 days post-infection. Calves and lambs were successfully infected, displaying respiratory signs (nasal discharge), moderate hyperthermia and leukopenia, viremia and viral shedding through the nasal and faecal routes. Antibody responses were observed in both animal species by ELISA and virus neutralisation assays. In contrast, inoculated piglets did not display any clinical signs nor leukopenia and viral RNA was not detected in any biological samples. Nevertheless, the presence of detectable antibodies by virus neutralisation accounted for a successful, albeit limited infection of these animals.     

Differential diagnosis of classical swine fever and border disease: seroepidemiological investigation of a pestivirus infection on a mixed sheep and swine farm.]

During recent years neutralizing antibodies against Border Disease Virus (BDV) were found repeatedly in German pig herds. Consequently there was a demand for a differential diagnostic system. A permanent sheep cell line and BDV reference strain Moredun were chosen and were applied in a could be used case study. A pestivirus could be isolated from piglets on a mixed farm and was characterised as 'non-Classical Swine Fever' (CSF) by using monoclonal antibodies. Due to a CSF suspicion the pig herd was destroyed immediately. Serum samples of sheep from the same farm were used for further characterisation of the new virus isolate. A neutralization test of the sheep sera was performed against different pestiviruses and the new isolate. Neutralizing antibody titres against the new virus pig isolate were significantly higher than against all other pestiviruses. BDV strain Moredun recognised the antibodies clearly, whereas CSF viral strain Alfort 187 and several isolates of bovine viral diarrhoea virus (BVDV) strains scored the lowest cross reaction.     

Genetic typing of bovine pestiviruses from England and Wales.

Using RNA purified directly from stored clinical specimens, a collection of 62 pestiviruses were typed by RT-PCR and sequencing within the 5'-untranslated region of the genome. All the specimens had been obtained in 1966/1967 from diary cattle in England and Wales. Eight further pestiviruses, grown in cell culture, were characterised in the same way. Seven of these viruses were representatives of a panel of British isolates, obtained from cattle ten years before. The eighth was the virus used in a British bovine viral diarrhoea (BVD) vaccine. Most of the viruses were genetically unique and were of BVDV type Ia. One recent isolate was BVDV type Ib, two others were intermediate between Ia and Ib. No BVDV type II or border disease virus (BDV) isolates were found. There was no overall association between geographical and phylogenetic clustering, suggesting long-distance virus dispersal, presumably via trading of infected cattle. The sequences of the recently obtained cattle viruses were very similar or, in one case, identical to the older isolates in the region studied. Their close similarity to some previously characterised pestiviruses from British sheep suggests that a common pool of BVDV Ia is shared by these two livestock species, although another pestivirus--BVDV--is confined to sheep. The British cattle viruses were mostly distinct from continental European isolates, but more similar to type Ia isolates from North American cattle.     

Variation in pestivirus growth in testicle primary cell culture is more dependent on the individual cell donor than cattle breed

The causes of bovine respiratory disease complex (BRDC) are multifactorial and include infection with both viral and bacterial pathogens. Host factors are also involved as different breeds of cattle appear to have different susceptibilities to BRDC. Infection with bovine pestiviruses, including bovine viral diarrhea virus 1 (BVDV1), BVDV2 and ‘HoBi’-like viruses, is linked to the development of BRDC. The aim of the present study was to compare the growth of different bovine pestiviruses in primary testicle cell cultures obtained from taurine, indicine and mixed taurine and indicine cattle breeds. Primary cells strains, derived from testicular tissue, were generated from three animals from each breed. Bovine pestivirus strains used were from BVDV-1a, BVDV-1b, BVDV-2a and ‘HoBi’-like virus. Growth was compared by determining virus titers after one passage in primary cells. All tests were run in triplicate. Virus titers were determined by endpoint dilution and RT-qPCR. Statistical analysis was performed using one way analysis of variance (ANOVA) followed by the Tukey’s Multiple Comparison Test (P?0.05). Significant differences in virus growth did not correlate with cattle breed. However, significant differences were observed between cells derived from different individuals regardless of breed. Variation in the replication of virus in primary cell strains may reflect a genetic predisposition that favors virus replication.