Human papovavirus (JC): induction of brain tumors in hamsters

Eighty-three percent of hamsters inoculated at birth with JC virus, a human papovavirus isolated from brain tissue of a case of progressive multifocal leukoencephalopathy, developed malignant gliomas within 6 months. Three brain tumors have been serially transplanted as subcutaneous tumors. JC virus was isolated from five of seven tumors tested. Cells from four tumors were cultivated in vitro. These cells contained an intranuclear antigen with the characteristics of a T antigen, and this antigen was antigenically related to SV40 T antigen. Although virus was not recovered from extracts of serially cultured tumor cells, JC virus was rescued when one tumor cell line was fused with permissive cells.     

The role of mononuclear phagocytes in HTLV-III/LAV infection

Cells with properties characteristic of mononuclear phagocytes were evaluated for infectivity with five different isolates of the AIDS virus, HTLV-III/LAV. Mononuclear phagocytes cultured from brain and lung tissues of AIDS patients harbored the virus. In vitro-infected macrophages from the peripheral blood, bone marrow, or cord blood of healthy donors produced large quantities of virus. Virus production persisted for at least 40 days and was not dependent on host cell proliferation. Giant multinucleated cells were frequently observed in the macrophage cultures and numerous virus particles, often located within vacuole-like structures, were present in infected cells. The different virus isolates were compared for their ability to infect macrophages and T cells. Isolates from lung- and brain-derived macrophages had a significantly higher ability to infect macrophages than T cells. In contrast, the prototype HTLV-III beta showed a 10,000-fold lower ability to infect macrophages than T cells and virus production was one-tenth that in macrophage cultures infected with other isolates, indicating that a particular variant of HTLV-III/LAV may have a preferential tropism for macrophages or T cells. These results suggest that mononuclear phagocytes may serve as primary targets for infection and agents for virus dissemination and that these virus-infected cells may play a role in the pathogenesis of the disease.     

Milker''s nodules: isolation of a poxvirus from a human case

A virus of the pox group was isolated from a lesion on a patient with milker's nodules by use of tissue cultures of bovine cells. The virus shows marked biologic and serologic differences from vaccinia virus, and it is presumably the etiologic agent of the milker's nodule syndrome.     

Continuously Cultured Tissue Cells and Viral Vaccines: Potential advantages may be realized and potential hazards obviated by careful planning and monitoring

1) Continuously cultured tissue cells afford numerous potential advantages for the propagation of viruses to be used in vaccines. 2) Because continuously cultured tissue cells sooner or later become capable of growing into neoplasms when transplanted into a suitable host, every possible precaution should be taken to ensure that viral vaccines grown in cell cultures are free from living cells and cell particles larger than 0.5 to 1.0 micron. 3) The radical abnormalities that occur in cell lines derived from neoplasms and those that develop sooner or later in cell lines derived from normal tissue cannot be ignored. However, no evidence has been recorded (i) that untoward consequences follow administration of cell-free preparations from such cultures to humans or (ii) that oncogenic or other viral activity is associated with the ability of cells of these lines to grow into neoplasms when transplanted into a suitable host. It seems very unlikely, nevertheless, that acceptance could be won at present for the general use of a live-virus vaccine prepared from a virus grown in cells showing evidences of malignancy. This conclusion is based more on psychological and public relations considerations than on the available scientific information, which, however, needs considerable augmentation. In this connection, careful consideration should be given to the question whether the absence of the cited kinds of abnormalities from a continuously cultured cell system is a sufficient indicator of freedom from oncogenic potential. In the absence of unfavorable data, we judge that present knowledge does not preclude judicious extension of clinical trials, in volunteers, of appropriately filtered and otherwise controlled experimental live-virus vaccines grown in carefully selected continuously cultured cell systems. Only in this way can sufficient data be collected, and adequate criteria be developed, to define eventually the conditions for acceptability of such preparations for general administration to humans. 4) Every possible effort should be devoted to the development of non-oncogenic and otherwise acceptable cell lines from normal tissues for use in viral vaccine production. It is suggested that exploratory studies begin with continuously cultured mixed-cell populations in the diploid state and stabilized cloned cultures. Criteria for the selection and monitoring of cell lines, and progressive steps leading to large-scale application are outlined. 5) If the need for immunization against a particular viral disease should be deemed sufficiently urgent, and if no practicable alternative were available, serious consideration might be given to a vaccine prepared by inactivating the virus, grown in such a selected stabilized cell line as HeLa or human skin epithelium. The conditions of preparation would have to be such as would inactivate the most resistant known viruses and infective nucleic acids with a generous margin of safety. 6) Principal areas needing intensified research emphasis are indicated.     

Kaposi's sarcoma cells: long-term culture with growth factor from retrovirus-infected CD4+ T cells

Studies of the biology and pathogenesis of Kaposi's sarcoma (KS) have been hampered by the inability to maintain long-term cultures of KS cells in vitro. In this study AIDS-KS-derived cells with characteristic spindle-like morphology were cultured with a growth factor (or factors) released by CD4+ T lymphocytes infected with human T-lymphotropic virus type I or II (HTLV-I or HTLV-II) or with human immunodeficiency virus type 1 or 2 (HIV-1 or HIV-2). Medium conditioned by HTLV-II-infected, transformed lines of T cells (HTLV-II CM) contained large amounts of this growth activity and also supported the temporary growth of normal vascular endothelial cells, but not fibroblasts. Interleukin-1 and tumor necrosis factor-alpha stimulated the growth of the KS-derived cells, but the growth was only transient and these could be distinguished from that in HTLV-II CM. Other known endothelial cell growth promoting factors, such as acidic and basic fibroblast growth factors and epidermal growth factor, did not support the long-term growth of the AIDS-KS cells. The factor released by CD4+ T cells infected with human retroviruses should prove useful in studies of the pathogenesis of KS.     

4株狂犬病毒感染小鼠的临床症状及脑组织病理学观察

[目的]对比狂犬病毒固定强毒株CVS-24、广西街毒株GX074、弱毒株rRC-HL和重组毒株rRC-HL△G感染小鼠后的临床症状及脑组织病理学变化,为揭示狂犬病毒的致病机理提供参考依据.[方法]将CVS-24、GX074、rRC-HL和rRC-HL△G分别通过脑内注射SPF级昆明小鼠,以注射DMEM为对照,每只小鼠注射30μL,攻毒后连续观察测量小鼠的体重和死亡情况,采取濒临死亡小鼠的脑组织制作石蜡切片,经HE染色后观察脑组织的病理变化.[结果]与DMEM组的小鼠相比,rRC-HL组小鼠攻毒后的体重先下降后恢复正常,而其他攻毒组小鼠的体重迅速下降直至死亡.DMEM组和rRC-HL组的小鼠在整个试验周期内未见死亡;CVS-24组、GX074组和rRC-HL△G组的小鼠在攻毒后全部发病死亡,其中,CVS-24组小鼠出现死亡的时间最早(攻毒后第5 d),且在攻毒后第6 d全部死亡.通过观察小鼠脑组织的病理学变化,发现rRC-HL组小鼠脑组织的炎症反应最严重,其神经纤维紊乱,神经元细胞变形,细胞边缘不清晰,少量细胞固缩甚至消失,海马回神经胶质细胞浸润,嗜神经现象明显,血管套现象严重;rRC-HL△G组次之;GX074组和CVS-24组小鼠的脑组织病变轻微,可见少量嗜神经现象.[结论]rRC-HL△G、GX074和CVS-24等3株狂犬病毒强毒株的临床症状更明显,发病死亡率达100%,但与弱毒株相比,其炎症反应较轻微,说明狂犬病毒强毒株可能是通过抑制机体脑组织中促炎因子的产生而抑制炎症反应出现,阻断其固有免疫反应,不利于机体对病毒的清除.     

Neoplastic transformation of hamster astrocytes in vitro by simian virus 40 and polyoma virus

Astrocytes in cultures of brain cells from fetal or newborn hamsters undergo neoplastic transformation after infection with simian virus 40 or polyoma virus. Subcutaneous or intracerebral inoculation of the transformed brain cells into newborn or adult hamsters produces progressively enlarging astrocytomas at the sites of injection. Astrocytomas produced by polyomatransformed cell lines are histologically better differentiated, but grow more rapidly and metastasize more frequently, than astrocytomas produced by cell lines transformed by simian virus 40. These observations make available in vitro models of virus-induced oncogenesis in astrocytes and provide simple techniques for obtaining astrocytoma cell lines suitable for screening studies of chemical agents effective against astrocytomas.     

Dual infection of the central nervous system by AIDS viruses with distinct cellular tropisms

Human immunodeficiency virus (HIV) is the causative agent of the acquired immune deficiency syndrome (AIDS). A large number of AIDS patients show evidence of neurologic involvement, known as AIDS-related subacute encephalopathy, which has been correlated with the presence of HIV in the brain. In this study, two genetically distinct but related viruses were isolated from one patient from two different sources in the central nervous system: brain tissue and cerebrospinal fluid. Both viruses were found to replicate in peripheral blood lymphocytes, but only virus from brain tissue will efficiently infect macrophage/monocytes. The viruses also differ in their ability to infect a brain glioma explant culture. This infection of the brain-derived cells in vitro is generally nonproductive, and appears to be some form of persistent or latent infection. These results indicate that genetic variation of HIV in vivo may result in altered cell tropisms and possibly implicate strains of HIV with glial cell tropism in the pathogenesis of some neurologic disorders of AIDS.     

Starch accumulation in shoot-forming tobacco callus cultures

Microscopic histochemical examinations of cultured tobacco callus disclosed a strong correlation between starch accumulation and shoot initiation. The accumulation started before any observable organized development and was heaviest in cells of loci which ultimately gave rise to organ primordia. Treatment of tissue cultures with gibberellin prevented starch accunmulation and organ formation.     

Amitotic neuroblastoma cells used for neural implants in monkeys

The potential utility of cultured neuroblastoma cells as donor tissue for neutral implants into the mammalian brain has been examined. Cells from a human neuroblastoma cell line, IMR-32, were labeled with [3H]thymidine and chemically rendered amitotic. These differentiated IMR-32 cells were grafted into the hippocampi of five adult African Green monkeys, and graft survival was evaluated for up to 270 days after transplantation. Autoradiographically labeled grafted cells were identified in four animals. Processes from grafted cells could be followed for distances of up to 150 micrometers into the host brain. No evidence for neoplastic growth of the transplant was found. Thus, grafted neuroblastoma cells can survive for prolonged periods in the primate brain and may serve as a practical source of donor tissue for neural implants.     

狂犬病Flury HEP株的复制及其某些生物学性质的观察

狂犬病ＦｌｕｒｙＨＥＰ株弱毒在ＢＨＫ（２１）细胞上连续传代，培养物经中和试验、间接荧光抗体染色、电镜观察、动物试验、病毒增殖和抗体消长曲线的测定，证明该弱毒株可在ＢＨＫ（２１）细胞上良好地复制。传至二代以后毒价可达到１０（－５）／０．０３ｍｌ。该毒经兔、犬、山羊、牛试验显示了其安全性。免疫后７天即可见到抗体阳转。免疫犬后，血清中和抗体在二年半时间内维持在一个较高的水平。     

Specific tropism of HIV-1 for microglial cells in primary human brain cultures

Human immunodeficiency virus (HIV) frequently causes neurological dysfunction and is abundantly expressed in the central nervous system (CNS) of acquired immunodeficiency syndrome (AIDS) patients with HIV encephalitis or myelopathy. The virus is found mostly in cells of the monocyte-macrophage lineage within the CNS, but the possibility of infection of other glial cells has been raised. Therefore, the effects of different HIV-1 and HIV-2 strains were studied in primary cultures of adult human brain containing microglial cells, the resident CNS macrophages, and astrocytes. These cultures could be productively infected with macrophage-adapted HIV-1 isolates but not with T lymphocyte-adapted HIV-1 isolates or two HIV-2 isolates. As determined with a triple-label procedure, primary astrocytes did not express HIV gag antigens and remained normal throughout the 3-week course of infection. In contrast, virus replicated in neighboring microglial cells, often leading to their cell fusion and death. The death of microglial cells, which normally serve immune functions in the CNS, may be a key factor in the pathogenesis of AIDS encephalitis or myelopathy.     

Radiation leukemia virus: quantitative tissue culture assay

Radiation leukemia virus does not propagate in tissue cultures from either Swiss or C57BL mouse embryos, but it does augment focus formation by the defective Moloney leukemia pseudotype of murine sarcoma virus in Swiss mouse cells and thus can be quantitatively assayed.     

Human brain tumor--derived cell lines: growth rate reduced by human fibroblast interferon

The biological response modifier human beta-interferon had pronounced antigrowth effects on various histologic types of human brain tumor cells but no effects on a nontransformed cell line, MRC-5. The cultures of brain tumor cells showed severe alterations indicative of cell injury and death after exposure to beta-interferon for 2 to 6 days. Similar results were obtained with cells freshly explanted from human brain tumors. The results indicate that it may be possible to use fresh, explanted tumor tissue to identify patients who might benefit from therapy with beta-interferon.     

Herpes-type virus and chromosome marker in normal leukocytes after growth with irradiated Burkitt cells

Cultured cells derived from male patients with Burkitt's lymphoma and harboring herpes-type virus particles were lethally irradiated. These irradiated cells induced normal peripheral leukocytes of female infants to grow within 2 to 4 weeks after mixed cultivation. Cells of a line free of this agent failed to stimulate growth. If either type of cell was cultured separately, it did not survive under the experimental conditions. Herpes-type viral antigen and C-group chromosomal marker previously described in cultured Burkitt cells were found in all of the female cell cultures that were obtained.     

黄芪多糖、淫羊萑多糖和淫羊萑总黄酮的城疫毒感染细胞的影响

将黄芪多糖（APS）、淫羊萑多糖（EPS）、淫羊萑总黄酮（EF）分别与新城疫病毒（NDV）Ⅰ、Ⅳ系以3种顺序加入到培养24h的鸡胚成纤维细胞（CEF）中，即先加中药后接种病毒、先接种病毒后加中药、病毒和中药混合感作后同时加入。于病毒接种后72h测定NDVⅠ系的半数组织培养感染剂量（TCID50）和NDVⅣ系的血凝效价，以评价3种中药成分对NDV感染细胞的影响。结果表明，APS和EPS仅在先于病毒加入时对NDV有抑制作用，而EF无论以何种方式给药均呈抑制作用。提示它们有一定的抗病毒作用，且与其浓度有相关性。     

猪伪狂犬病病毒的分离鉴定

从山西某猪场发病猪的脑组织中分离到1株疑为猪伪狂犬病病毒(PRV)毒株,通过BHK-21细胞培养、病毒毒力滴定、中和试验、PCR检测病毒方法对该分离株进行了鉴定,结果发现:分离的病毒在BHK-21细胞培养盲传4代后出现典型细胞病变;用BHK-21细胞测定其毒价TCID50为10-8.042/0.1 mL;PCR体外扩增可见其扩增片段与预期目的条带相一致;据此分离病毒株的上述特征,鉴定该病毒为猪伪狂犬病病毒,并命名为SX09。     

Type C RNA tumor viruses as determinants of chemical carcinogenesis: effects of sequence of treatment

Fischer rat embryo cells were treated with 3-methylcholanthrene before or after inoculation with Rauscher murine leukemia virus. Transformation was not observed in untreated control cultures, cultures given virus or 3-methyl-cholanthrene alone, or cultures treated first with 3-methylcholanthrene followed by inoculation with the virus after removal of the chemical. Transformation was dependent upon the presence of Rauscher murine leukemia virus at the time of chemical treatment.     

Infection of normal human epithelial cells by Epstein-Barr virus

Primary cultures of epithelial cells were grown from the tonsils and adenoids of patients with diseases not related to Epstein-Barr virus. The cells could not be infected by Epstein-Barr virus. Fluorescein-labeled Epstein-Barr virus and a cytofluorograph were then used to show that the epithelial cells do not have detectable receptors for the virus. However, implantation with Epstein-Barr virus receptors gave the cells the ability to bind the labeled virus. One to 5 percent of receptor-implanted cells exposed to the transforming B95-8 substrain of the virus expressed Epstein-Barr nuclear antigen. The early and viral capsid Epstein-Barr virus-determined antigens were not detected in the virus-infected cultures. The results show that normal human epithelial cells from the nasopharynx become susceptible to infection by Epstein-Barr virus when the membrane barrier resulting from the lack of viral receptors is overcome by receptor implantation.     

高致病性猪繁殖与呼吸综合征病毒在自然病例组织中的定位

猪繁殖与呼吸综合征（PRRS）是由猪繁殖与呼吸综合征病毒（PRRSV）引起,以怀孕母猪发生流产、早产和死胎等严重的繁殖障碍及仔猪和育肥猪发生呼吸道疾病为主要症状的传染病,是一种免疫抑制性疾病。猪感染PRRSV后的组织学病理变化主要集中在肺脏和淋巴结等器官;急性PRRS表现为败血症,全身性巨噬细胞和血管内皮细胞肿大、活化或增生,间质性肺炎,