单克隆抗体对肾综合征出血热病毒50k蛋白的分析

用18株抗肾综合征出血热(Hemorrhagic fever with renal syndrome,以下简称HFRS)病毒McAb,以Western-blot技术分析了纯化的该病毒50k蛋白。结果有7株McAb可与该蛋白反应。这7株McAb的特性(包括感染细胞膜抗原免疫荧光染色模式、中和活性及HI活性等)亦各不相同,提示它们所针对的抗原决定簇的特性也不同。用ELISA阻断试验等证明,上述7株McAb中,有5株所针对的抗原决定簇之间有部分相同或重叠,提示这些具有不同特性的抗原决定簇确实位于同一结构蛋白上。分析结果表明,该50k蛋白的特性及结构均较复杂,尚须进一步研究。     

纸坊病病毒病因的研究

1985年4～10月与1986年6～8月,在贵州省沿河县的纸坊村和崔家坨村先后发生了病因不明的传染病。纸坊村约有1/5的村民发病,病死率为12％,崔家坨村有1/10的村民发病,病死率高达30％。发病波及各年龄组,以青壮年为多,有家庭集聚现象。 本病起病急,轻症者只有头晕、乏力、肌痛、多汗、心悸伴以低热,有的初期有短暂的腹泻。重症者有高热(40℃以上)、大汗、心悸、游走性肌肉痉挛伴有明显疼痛和触痛,以腰骶部及四肢肌肉为好发部位。病人烦燥不安,2～5天内死亡。经实验室检查,排除了食物中毒、农药中毒、钩端螺旋体病和弓形体感染。从病人和接触者的粪便中分离到9株病毒,性状一致,为RNA型25nm的球形颗粒,耐酸,耐乙醚,能凝集人“O”型血球。经血清学鉴定为ECHO3型病毒。16份病人双份血清的检测结果表明,恢复期血清对该病毒中和抗体有4倍以上升高者共8例(纸坊村和崔家坨各4例)。病人单份血清也都有较高的抗体。有理由认为两年中先后在两个村庄发生的传染病与ECHO3型病毒有密切关系。查阅文献,尚未见有关ECHO3型病毒引起以肌痛、游走性肌痉挛为特征的疾病的报道。     

用体外免疫法建立人—人抗流行性乙型脑炎病毒杂交瘤细胞株

利用单克隆抗体(McAb)进行病毒病的治疗是人们所关心的一个重大课题。 流行性乙型脑炎(乙脑)是一种严重威胁人民健康的急性传染病,病死率高,后遗症严重。国内外目前尚无特效疗法。陈伯权等用乙脑病毒皮下或腹腔感染3周龄小白鼠24、48小时及5天后,分别用乙脑病毒51-8McAb进行治疗,平均治愈率分别为78％、73％及22％。     

流行性出血热病毒R22株cDNA克隆及其特异性鉴定

用家鼠型流行性出血热病毒R22株RNA,经polyA接尾,以Oligo-dT做引物,合成cDNA。用pUC18为载体转染E.coli Mc1061,建立cDNA克隆。再经菌落杂交,选择病毒特异性的5个阳性克隆制成缺口翻译探针,与病毒RNA3个片段进行反杂交,确定RNA片段的特异性。结果表明,3个克隆为中(M)片段的cDNA,另两个分别为大(L)和小(S)片段cDNA。核苷酸序列分析证明,克隆的DNA中含病毒特异的核苷酸序列。     

Resistance ofSpodoptera frugiperda [Lep.: Noctuidae] to a nuclear polyhedrosis virus in the field and laboratory

Median lethal doses (LD₅₀s) of nuclear polyhedrosis virus (NPV) were determined in neonatal offspring ofSpodoptera frugiperda (J. E. Smith) (Sf) larvae captured in southeastern Louisiana in 1981, 1982, and 1984. These LD₅₀s ranged from 1.8 to 16.3 polyhedral inclusion bodies (PIB)/insect. The LD₅₀s significantly (P<0.05) increased during the season of 1982 but had no pattern in 1981 or 1984. However, the Sf populations increased in heterogeneity of response to the NPV during all 3 years. The LD₅₀ increased from 4.1 to 18.7 PIB/insect in a Sf laboratory colony exposed to the NPV LD₈₀ for 7 generations, whereas in a control colony not exposed to NPV the LD₅₀ was 5.9 PIB/insect after 7 generations.     

Persistent measles virus infection enhances major histocompatibility complex class I expression and immunogenicity of murine neuroblastoma cells

The effect of persistent measles virus infection on the expression of major histocompatibility complex (MHC) class I antigens was studied. Mouse neuroblastoma cells C1300, clone NS20Y, were persistently infected with the Edmonston strain of measles virus. The persistently infected cell line, NS20Y/MS, expressed augmented levels of both H-2K^k and H-2D^d MHC class I glycoproteins. Activation of two interferon(IFN)-induced enzymes, known to be part of the IFN system: (2–5)oligoadenylate synthetase and double-stranded-RNA-activated protein kinase, was detected. Measles-virus-infected cells elicited cytotoxic T lymphocytes that recognized and lysed virus-infected and uninfected neuroblastoma cells in an H-2-restricted fashion. Furthermore, immunization of mice with persistently infected cells conferred resistance to tumor growth after challenge with the highly malignant NS20Y cells. The rationale for using measles virus for immunotherapy is that most patients develop lifelong immunity after recovery or vaccination from this infection. Patients developing cancer are likely to have memory cells. A secondary response induced by measles-virus-infected cells may therefore induce an efficient immune response against non-infected tumour cells.     

Idiotype network components are involved in the murine immune response to simian virus 40 large tumor antigen

Summary Baculovirus-derived recombinant simian virus 40 (SV40) large tumor antigen (SV40 T-Ag), a monoclonal antibody specific for SV40 T-Ag (Ab-1 preparation), and a monoclonal anti-idiotypic antibody (anti-Id), designated 58D, were used to analyze the humoral immune response of Balb/c mice either immunized with recombinant SV40 T-Ag or challenged with SV40-transformed cells. Inhibition assays indicated that antibodies from mice immunized with SV40 T-Ag and from those bearing SV40 tumor inhibited the SV40 T-Ag/Ab-1 reaction. These data suggested that the antibody response in immunized or tumorchallenged mice recognized similar epitope(s) on SV40 T-Ag to that detected by the monoclonal Ab-1. These anti-(SV40 T-Ag) response antibodies also inhibited the Ab-1/anti-Id reaction and recognized the anti-Id in direct binding assays. Together, these data indicate that murine anti-(SV40 T-Ag) responses shared an idiotope with a monoclonal anti-(SV40 T-Ag) Ab-1 preparation. This idiotope, which is recognized by the monoclonal anti-Id preparation, 58D, appears to be involved in the humoral immune response to SV40 T-Ag in both SV40-T-Ag-immunized and tumor-bearing mice. The monoclonal anti-Id preparation may represent a focal point for manipulating the humoral immune response to tumors induced by SV40-transformed cells.     

Molecular mimicry and the autoimmune response to the peripheral nerve myelin PO glycoprotein

In the Lewis rat immunisation with the myelin PO glycoprotein can induce an inflammatory demyelinating disease of the peripheral nervous system, experimental allergic neuritis (EAN), which has many clinical and histopathological parallels with the human disease the Guillain-Barre syndrome. In view of the reported association of GBS with a number of infectious agents we have investigated whether molecular mimicry may occur between microbial antigens and the PO protein that could possibly trigger a similar pathogenic autoimmune response in man. A computer search of the available protein sequence data bases identified several absolute sequence homologies between PO and viral proteins that involve five or more consecutive amino acid residues. Four of these sequence homologies involved viral pathogens previously associated with the Guillain-Barre syndrome, namely Epstein-Barr virus (EBV), cytomegalovirus (CMV), Varicella zoster virus (VZV) and human immunodeficiency virus I (HIV I). Although, sequence homologies were also found between viral peptides and the neuritogenic determinants of PO, residues 56–71 and 180–199, these homologies proved incapable of eliciting EAN in the Lewis rat. These observations are discussed with reference to the role that molecular mimicry between T cell epitopes on pathogen derived antigens and the PO protein may play in the pathogenesis of the Guillain-Barre syndrome.Abbreviations EAN Experimental allergic neuritis - EAE experimental allergic encephalomyelitis - PNS peripheral nervous system - CNS central nervous system - MBP myelin basic protein - GBS Guillain Barre syndrome - CFA complete Freund's Adjuvant - LPC lysophosphatidyl choline - VZV Varicella zoster virus - CMV cytomegalovirus - EBV Epstein Barr virus - HIV I human immunodeficiency virus I Special issue dedicated to Dr. Alan N. Davison     

马铃薯Y病毒外壳蛋白基因的克隆及序列分析

本文报道应用聚合酶链式反应(PCR)技术,在体外扩增马铃薯 Y 病毒外壳蛋白基因及其克隆和序列分析的结果。病毒 RNA 从马铃薯 Y 病毒感染的烟草叶片中提取,用合成的PCR 3引物及 AMV 逆转录酶合成了单链的 cDNA。利用 PCR 技术,经30个循玎的扩增。得到了一特异的0.8kb 片段。克隆后对此片段进行了限制性内切酶物理图谱分析,并测定了其全序列。实验结果证明,我们克隆到的是完整的马铃薯 Y 病毒的外壳蛋白基因。与国外报道的马铃薯 Y 病毒 N 株相比,其核苷酸序列及推测的氨基酸序列的同源率分别为97.8%和97%。将该基因导入马铃薯以期获得抗 Y 病毒马铃薯的工作正在进行。本文还对 PCR 技术用于扩增植物 RNA 病毒的方法以及用基因工程方法培育抗病毒作物新品种的可行性等进行了讨论。     

Experimental approaches to guarantee minimal risk of potential virus in purified monoclonal antibodies

Regarding biological products, increasing awareness of potential side effects have placed great importance not only at protein purity regarding other proteins but on the removal of biologicals such as DNA and especially virus the importance of which may not be known. Monoclonal antibodies (Mab) have come to be an important class of molecules obtained from hybridoma cells, i.e., nonrecombinant cells in culture. It has been noted during the last years, that with rare exceptions hybridoma cell lines contain retrovirus like particles. The infectious nature of the EM-visible particles has been tested for, however, in most cases not been substantiated. In order to bring these valuable biological reagents, Mab's, to good use in man for imaging or therapy, the remaining concern about a potential retroviral infection has to be reduced to an acceptable minimum. We describe experimental approaches for the validation of chromatographic and ultrafiltration steps used in the production of monoclonal antibodies to remove and inactivate murine retrovirus. Present day biotechnological manufacturing processes have been devised incorporating a number of strategic preventive measures that have found wide spread acceptance. They permit to answer the question: how can a potentially harmful infection by an unknown virus be excluded. Knowledge of the efficacy of purification steps to clear infectious model virus is fundamental to devise biotechnological manufacturing processes yielding a purified antibody for use in man.