Production of Reference Enteroviruses

Forty-five human enterovirus reagents of certified purity and quality were prepared for use as seed viruses and as immunizing antigens. One of the reagents was ampouled as "untreated" seed virus, whereas 14 were ampouled as "MgCl(2)-stabilized" reagents. The remaining 30 reagents were ampouled as "untreated" seed viruses and as "MgCl(2)-stabilized" reagents. Thirty of the reagents were propagated on primary African green monkey kidney cells, 3 on primary baboon kidney cells, 3 on primary rhesus monkey kidney cells, and the remaining 9 on human amnion cells. Forty-two of the viral antigens were concentrated for use in the production of high-titered specific antisera in large animals.     

Studies on the pathogenicity of human-origin parainfluenza virus in the brain of mice.

The pathogenicity of parainfluenza type 2 (croup-associated) virus known to cause infections of the respiratory tract in the early life of man was studied in the brain of mice. One- to 4-day-old sucklings and 4-week-old mice were inoculated intracerebrally with the virus. The virus multiplied in sucklings, but not in adults. Most mice inoculated intracerebrally with the virus appeared healthy. Histological examination showed minimum inflammatory changes, although moderate hydrocephalus developed in three of twenty-one sucklings by 6 weeks post-infection. Immunofluorescent study in sucklings showed viral antigens in ependymal lining cells and choroid plexus epithelium during the first two weeks, and parenchymal cells for more than two months. Virus specific antibody response was observed in adults, but not in sucklings. One interesting finding was that viral antigens persisted in six out of 11 suckling brains for one to two months.     

Studies on Parainfluenza Virus Infections among Infants and Children in Sendai

A cell line sensitive enough for the recovery of all parainfluenza viruses and free of simian virus contamination frequently occurring in monkey kidney cells was sought. The VERO cell obtained from African monkey kidney was found suitable for the initial isolation of types 1, 2 and 3 parainfluenza viruses, although the cells did not always allow the successive transfer. Mixed cultures of VERO and HEp-2 cells were also useful in the recovery of various respiratory viruses including parainfluenza viruses. The characteristics of hemagglutinins of parainfluenza viruses were examined, and type 2 parainfluenza and SV5 viruses agglutinated both guinea pig and green monkey erythrocytes at 36 C, whereas types 1 and 3 parainfluenza viruses agglutinated only guinea pig erythrocytes. Thus parainfluenza viruses were divided into two groups by the presence or absence of hemagglutinins for green monkey erythrocytes. Identification of these parainfluenza isolates, employing HI microtechnique was simple and reliable, even with the first passage harvest, when guinea pig erythrocytes were used and the test read at 36 C. Specific standard antisera for these parainfluenza viruses were prepared by immunizing chickens intravenously and bleeding within a short period. These type-specific antisera were useful for the identification of parainfluenza isolates by HI test.     

Preliminary note on the circulation of some human respiratory viruses by wild birds]

With a view to detecting infections and carriage of human respiratory viruses in wild birds, 349 serum samples collected from 21 bird species -- sedentary ones and birds with large or limited migration areas -- were investigated. The following antigens were used: influenza virus A/Hong Kong 1/68 (H3N2)), A2 England 42/73 (H3N2), A2 Victoria 3/75 (H3N2), A/New Jersey 8/76 (HswN1), B/Hong Kong 5/72; parainfluenza virus type I Sendai and type II, coronavirus OC/43. An elevated incidence of antibodies to A2 Victoria 3/75 (H3N2) and parainfluenza type I virus was detected in herons (Ardea cinerea, Nyctycorax myctycorax). The high incidence of antibodies to B/Hong Kong 5/72 (30.7% of the samples exhibited significant titers) found in the crow (Corvus corone sardonius) is ascribed to the fact that this bird is carnivorus, feeding on corpses of mammals.     

Properties of Noninfectious and Transforming Viruses Released by Murine Sarcoma Virus-Induced Hamster Tumor Cells

The cell culture lines HTG2 and HTG3 were established from a transplantable hamster tumor induced by a murine sarcoma virus (strain Gz-MSV) after 17 and 60 in vivo passages, respectively. The viruses released by these two cell lines markedly differ in morphology, antigenic composition, infectivity, transforming ability, and enzymatic activity. HTG2 virions contained the sarcoma genome but were noninfectious for mouse and hamster cells (S+H-virus). HTG3 virions transformed hamster but not mouse cells. Whereas HTG2 cells and its virus contained murine type C virus gs-1 antigen, all HTG3 clonal lines expressed both murine and hamster type C virus gs-1 antigens. The RNA-dependent DNA polymerase activity of HTG2 virus was very low, whereas that of HTG3 virus was relatively high. HTG2 virions contained electron-lucent centers only. HTG3 virus consisted of the expected mixture of virions with electron-dense and electron-lucent centers. Many broken or incomplete virions were present in both viruses. HTG2 virus is a noninfectious "defective" sarcoma virus without detectable helper virus. Data obtained in these experiments suggest that HTG3 virus is a hamster type C virus pseudotype of Gz-MSV (Gz-MSV [HaLV]). The genome of Gz-MSV is capable of antigenic expression in heterologous cells and in the presence of heterologous viruses. Attempts to chemically activate hamster type C virus (HaLV) from HTG2 cells were unsuccessful. The HTG1 cell culture line, established from another Gz-MSV-induced hamster tumor, initially released a virus indistinguishable from the HTG2 virus. After in vitro passage, spontaneous activation of HaLV occurred in HTG1 cells, and the resultant Gz-MSV (HaLV) had properties similar to those of the HTG3 virus.     

Some biological and physical properties of molluscum contagiosum virus propagated in cell culture.

Molluscum contagiosum virus propagated in FL cells of human amnion origin has a one-step growth cycle time of 12 to 14 h. The appearance and exponential increase of intracellular virus preceded the release of extracellular virus by approximately 2 h. Demonstration of comparable titers of extracellular and intracellular virus at the end of the replication cycle indicated that a substantial amount of virus remained associated with cells exhibiting cytopathogenic changes. Mean buoyant density values of virus in sucrose ranged from 1.275 to 1.278 g/cm3, but in CsCl the virus banded at densities at 1.325 to 1.340 and 1.261 to 1.281 g/cm3. Although virus infectivity was not affected by high concentrations of CsCl, it was found by polyacrylamide gel electrophoresis that the salt removed several nonglycosylated polypeptides with estimated molecular weights of 15,000 to 60,000. This suggested that the high-density band (1.325 to 1.340) may reflect the loss of these structural components. The half-life of virus infectivity was approximately 26.5 h at 26 degrees C and 11.2 h at 37 degrees C. Although the virus was rapidly inactivated at 50 degrees C, it could be stabilized at this temperature by the presence of 1.0 M MgCl2. Virus did not agglutinate newborn chick, adult chicken, or type "0" human erythrocytes. Virus infectivity was found to be sensitive to acid pH but resistant to treatment with diethyl ether or chloroform. The replication of molluscum virus in FL cells was not inhibited by 5-iodo-2'-deoxyuridine, 5-bromo-2'-deoxyuridine, or cytosine arabinonucleoside in noncytotoxic concentrations of 200 to 400 mug/ml, but greater than 99% reduction in the yield of herpes simplex virus or vaccinia virus in FL cells was obtained with 200 mug of these compounds per ml. Guanidinium chloride in concentrations of 100 to 200 mug/ml reduced molluscum virus yields by more than 99.9%.     

Studies on the epidemiology of child infections. 3. Parainfluenza viruses (types 1-4) and respiratory syncytial virus infections.

A seroepidemiological study on the rate of neutralizing antibodies for parainfluenza viruses (types 1-4) and for the respiratory syncytial virus in 2,514 infants and children between 0 and 15 years, residing in Bari and its hinterland was carried out. Positive results were very high for both the individual parainfluenza serotypes (81.7% for type 3, 78.0% for type 1, 76.6% for type 4, 71.9% for type 2) and for respiratory syncytial virus (88.5%). The pattern of infections due to respiratory syncytial virus differed from that of the parainfluenza viruses not only for the higher serologic positive rate, but also for the larger number of elevated titre responses in each age group.     

Growth of Myxovirus parainfluenza type 3 in organ cultures of guinea pig tissue

Craighead, J. E. (Harvard Medical School, Boston, Mass.). Growth of Myxovirus parainfluenza type 3 in organ cultures of guinea pig tissue. J. Bacteriol. 92:751-761. 1966.-Organ cultures of adult guinea pig nasal mucosa, lung, and pleura were infected with Myxovirus parainfluenza type 3. Observations were made on the growth of virus at intervals after inoculation. An inoculum of 10(2.5) tissue culture infectious doses (tcid(50)) initiated infection in each of the tissues. Cultures of nasal mucosa yielded up to 10(6.0)tcid(50) per 6 hr for periods of as long as 2 weeks. Virus production was not affected by the "immune" status of the animal used as a source of tissue. Introduction of antiserum into the medium appeared to suppress virus release but failed to "cure" the infection. Interferon was not detected in fluids bathing the nasal mucosa. Cultured fragments of lung produced virus for 28 days after inoculation. As much as 10(5.0)tcid(50) per 6 hr was released by the tissue. Pleural mesothelial cells lining the diaphragm yielded up to 10(6.0)tcid(50) per 6 hr over a 14-day period. Histological sections showed that the tissues retained differentiated morphological features during maintenance in vitro. Cytological changes unequivocally associated with infection were not recognized. The techniques described give reproducible, quantitative results. Organ cultures are feasible for the study of virus growth and cytopathology in differentiated tissues.     

Induction of murine p30 by superinfecting herpesviruses.

The interaction of endogenous type C viruses with superinfecting herpes simplex virus type 2 (HSV-2) was investigated in two murine cell lines. Replication of HSV-2 was suboptimal in random-bred Swiss/3T3A cells and, in initial experiments, infection with a low virus-to-cell ratio resulted in carrier cultures with enhanced murine leukemia virus (MuLV) p30 expression. Immunofluorescence tests with Swiss/3T3A cells productively infected with HSV-2 also showed HSV-associated cytoplasmic antigens and enhanced MuLV p30 expression when compared with uninfected controls. Inactivation of HSV-2 with UV light did not abolish this reaction, although the number of cells expressing p30 was reduced. HSV-2 replicated more efficiently in a line of NIH Swiss cells (N c1 A c1 10). These cells are not readily inducible for type C expression by conventional methods; however, untreated and UV-inactivated HSV-2 induced both HSV-2-associated antigens and MuLV p30 in these cells. Although the Birch strain of human cytomegalovirus induced MuLV p30, neither mouse cytomegalovirus nor vesicular stomatitis virus induced MuLV p30 in either cell line.     

Role of heterogenized cellular antigens in cross immunity reactions in paramyxovirus infections]

Heterogenized antigens similar to the antigens of sheep and guinea pig red blood cells were revealed by indirect immunofluorescence in tissue cultures infected with parotitis virus. Participation of these antigens in cross immunofluorescence reactions observed in tissue cultures infected with various paramyxoviruses and in a suspension of erythrocytes loaded with these viruses was established. It was shown that immunization of children with parotitis virus was accompanied by a specific anamnestic reaction for heterogenized antigens. It is supposed that the corresponding antibodies can take part in cross serological tests with parainfluenza viruses.     

Identification of two essential aspartates for polymerase activity in parainfluenza virus L protein by a minireplicon system expressing secretory luciferase

Gene expression of nonsegmented negative‐strand RNA viruses (nsNSVs) such as parainfluenza viruses requires the RNA synthesis activity of their polymerase L protein; however, the detailed mechanism of this process is poorly understood. In this study, a parainfluenza minireplicon assay expressing secretory Gaussia luciferase (Gluc) was established to analyze large protein (L) activity. Measurement of Gluc expression in the culture medium of cells transfected with the minigenome and viral polymerase components enabled quick and concise calculation of L activity. By comparing the amino acid sequences in conserved region III (CRIII), a putative polymerase‐active domain of the L protein, two strictly conserved aspartates were identified in all families of nsNSV. A series of L mutants from human parainfluenza virus type 2 and parainfluenza virus type 5 showed that these aspartates are necessary for reporter gene expression. It was also confirmed that these aspartates are important for the production of viral mRNA and antigenome cRNA, but not for a polymerase‐complex formation. These findings suggest that these two aspartates are key players in the nucleotidyl transfer reaction using two metal ions.     

Characterization of the major phosphoinositide-specific phospholipase C of human amnion

Most of the phosphoinositide-specific phospholipase C activity in human amnion at term was found to be attributable to a single isoform (Mr 85,000). Phospholipase C purified from amnion catalyzed the calcium-dependent hydrolysis of both phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate. The high phospholipase C activity of amnion cells isolated at 38-41 weeks of gestation declined greater than 80% during the initial 2-5 days of culture to values characteristic of amnion tissue in early gestation. Activities of phospholipase A2 and phosphatidylinositol synthase remained essentially unaltered during this period of culture. Loss of phospholipase C activity was apparently due neither to the appearance of an inhibitor nor to the loss of an activator and most likely reflected a decrease in the amount of enzyme in amnion cells. Basal production of prostaglandin E2 (PGE2) by amnion cells also declined greatly during the period of loss of phospholipase C activity. Involvement of phospholipase C in the regulation of amnion prostaglandin production was also supported by the finding that the phospholipase C inhibitor, U-73122, potently inhibited amnion cell PGE2 production. In contrast, vasopressin, which appears to stimulate prostaglandin production in amnion cells by a phospholipase C-dependent mechanism, was equipotent in stimulating PGE2 production by amnion cells on Day 2 and Day 5 of culture, even though phospholipase C activity had declined by more than 75%. Furthermore, epidermal growth factor stimulation of PGE2 production by amnion cells appeared to be largely attributable to an increase in prostaglandin H synthase activity and did not involve an increase in phospholipase C activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Stimulation of Herpesvirus saimiri Expression in the Absence of Evidence for Type C Virus Activation in a Marmoset Lymphoid Cell Line

Nucleic acid base analogues were used to examine a Herpesvirus saimiri (HVS)-infected marmoset lymphoid cell line (MLC-1) for possible association with type C viruses. Synthetic templates poly(rA).d(pT)(10) and poly(dA).d(pT)(10) were used to detect RNA-directed DNA polymerase activity in 100-fold concentrated tissue culture fluids. HVS was monitored by immunofluorescence for early, late, and membrane antigens. MLC-1 cells were exposed to 30 mug of 5-bromo-2'-deoxyuridine (BUdR) per ml for 24 h and examined daily. Similar experiments used 5-iodo-2'-deoxyuridine (IUdR) (20 mug/ml) for 30 h or IUdR (20 mug/ml) for 3 days followed by 2% dimethyl sulfoxide for 4 days. Results of these experiments failed to show any type C virus-like polymerase; however, HVS expression was greatly stimulated. BUdR and IUdR enhanced expression of HVS-associated antigens five- to sevenfold, with maximal stimulation being observed 3 to 4 days after removal of the analogue. IUdR-dimethyl sulfoxide treatment was generally less effective. Although more cells showed HVS antigens, the treatments did not increase cell-free infectious virus. The data suggest that HVS-infected lymphoid cells can be stimulated to express virus in a manner similar to that of the Epstein-Barr virus in Burkitt's lymphoma cells. No evidence of type C virus was found in stimulated cultures.     

Interaction of herpes simplex virus type 2 with a rat glioma cell line

The interaction between herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) and two neural cell lines, mouse neuroblastoma (N1E-115) and rat glioma (C6-BU-1), was investigated. N1E-115 cells were permissive to both types of HSV. In C6-BU-1 cells, on the other hand, all the HSV-1 strains tested so far showed persistent infection, and the infectious virus of HSV-2 strains disappeared spontaneously. The HSV-2-infected C6-BU-1 cells were positive for HSV-2-specific DNA sequences, virus-specific RNA, HSV-2-specific antigens and thymidine kinase activity, when no infectious virus was detected. The HSV-2 was reactivated from those C6-BU-1 cells by superinfection with murine cytomegalovirus (MCMV), but not with UV-irradiated MCMV or human cytomegalovirus. The reactivated HSV-2 was identical to the parental virus, when examined by restriction endonuclease cleavage analysis.     

GeXP多重PCR技术同时检测12种常见呼吸道病毒

本研究建立了一种基于GeXP多重基因表达遗传分析系统的多重RT-PCR检测方法,该方法可以同时检测12种呼吸道病毒,包括流感病毒A型和B型、季节性H1N1、副流感病毒1～3型、人鼻病毒、人偏肺病毒、腺病毒、呼吸道合胞病毒A型和B型、人博卡病毒。针对病原体保守区序列设计12种病毒的特异性引物,分别用已验证的阳性标本为模板检验多重体系的特异性。多重检测体系在10~3拷贝/μL水平可同时检测到12种病毒。另检测24份临床标本,以real-time RT-PCR为参考标准,进一步验证检测体系。结果表明,这种基于GeXP系统的新方法灵敏度高、特异性强,可以快速同时检测12种常见呼吸道病毒。     

Endogenous ecotropic mouse type C viruses deficient in replication and production of XC plaques.

Endogenous ecotropic type C viruses were induced by iodedeoxyuridine from nontransformed and chemically or spontaneously transformed clones of the C3H/10T1/2 cell line. Viruses produced by cells of certain transformed clones were N-tropic and formed large XC plaques. In contrast, viruses produced by nontransformed C3H/10T1/2 cells were not detectable in the XC plaque test. These XC- viruses infected mouse cells with high efficiency, as shown by the induction of murine leukemia virus group-specific antigens in infected cells, but virus production, as determined by DNA polymerase-containing particles, was extremely low. Upon growth in certain mouse cells these replication-deficient, XC(-) viruses converted to type C viruses that were similar in XC assays to N-tropic AKR virus (XC+).     

Mutant analysis of herpes simplex virus-induced cell surface antigens: resistance to complement-mediated immune cytolysis.

BHK-21 cells infected with temperature-sensitive mutants of herpes simplex virus type 1 strain KOS representing 16 complementation groups were tested for susceptibility to complement-mediated immune cytolysis at permissive (34 degrees C) and nonpermissive (39 degrees C) temperatures. Only cells infected by mutants in complementation group E were resistant to immune cytolysis in a temperature-sensitive manner compared with wild-type infections. The expression of group E mutant cell surface antigens during infections at 34 and 39 degrees C was characterized by a combination of cell surface radioiodination, specific immunoprecipitation, and gel electrophoretic analysis of immunoprecipitates. Resistance to immune lysis at 39 degrees C correlated with the absence of viral antigens exposed at the cell surface. Intrinsic radiolabeling of group E mutant infections with [14C]glucosamine revealed that normal glycoproteins were produced at 34 degrees C but none were synthesized at 39 degrees C. The effect of 2-deoxy-D-glucose on glycosylation of group E mutants at 39 degrees C suggested that the viral glycoprotein precursors were not synthesized. The complementation group E mutants failed to complement herpes simplex virus type 1 mutants isolated by other workers. These included the group B mutants of strain KOS, the temperature-sensitive group D mutants of strain 17, and the LB2 mutant of strain HFEM. These mutants should be considered members of herpes simplex virus type 1 complementation group 1.2, in keeping with the new herpes simplex virus type 1 nomenclature.     

Hybrids of human and monkey adenoviruses (adeno-adeno hybrids) that can reproduce in monkey cells: biological and molecular genetic peculiarities

A highly oncogenic monkey adenovirus SA7(C8) facilitates the reproduction of human adenovirus type 2 (Ad2) in monkey cells. Upon mixed infection of monkey cells with both viruses, these viruses recombine producing defective adeno-adeno hybrids Ad2C8 serologically identical to Ad2 and capable of assisting Ad2 to reproduce in monkey cells. Ad2C8 and Ad2 form an intercomplementary pair inseparable in monkey cells. Unlike oncogenic SA7(C8), Ad2C8 is a nononcogenic virus for hamsters but is able to induce tumor antigens of this virus (T and TSTA). Molecular genetic analysis of 68 clones of adeno-adeno hybrids revealed that the left part of their genome consists of Ad2 DNA, and the right part contains no less than 40% of the viral SA7(C8) genome where E2A, E3, and E4 genes are located. Apparently, the products of these genes contribute to the composition of adenoviral tumor antigens, while the E4 gene is involved in complementation of monkey and human adenoviruses and makes a contribution to host range determination of these viruses.