摘要:

Five thymidine kinase (TK)-deficient mutants of varicella-zoster virus derived from the Oka vaccine strain were examined to determine the state of transcription of the TK gene, and the DNA sequences of two of the mutants and the parent strain were investigated. Restriction endonuclease analysis revealed no major alteration of whole genome organization, but did reveal a minor change of the cleaved fragment in size. Northern blot analysis showed that the transcripts from the TK gene of all five mutants were of the same size as that of the parent strain (1.6 kb). DNA sequences of the TK gene of the parent strain and those of two mutants were determined. One had a base substitution (C to T) in the coding region of TK, resulting in the termination of amino acid elongation in the 68th amino acid of 341. The other had a two-base deletion (AT) in the coding region, resulting in a frame shift from the 126th amino acid and termination at the 162nd amino acid. Both mutants had premature stop codons which might result in the synthesis of nonfunctional TK polypeptides. Thus, the molecular basis of TK deficiency was determined.

ISSN:0300-5526    

DOI:10.1159/000150060

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Cell lines transformed by bovine papillomavirus type 1 DNA were established from transfected primary fibroblast cultures of C57BL/6 mice. Southern blot analysis revealed that most of the viral DNA in the cells was in episomal oligomeric form. These cell lines were tested for tumorigenicity in nude mice in comparison to properties associated with malignant transformation including growth in low-serum medium, focus formation in agar, and resistance to natural killer cells. Two of the 5 cell lines were highly tumorigenic, producing spindle cell sarcomas in all animals. Metastatic spreading to local lymph nodes was also observed. The same cell lines also showed anchorage-independent growth in agar, but no correlation was observed between natural killer cell resistance and tumorigenicity. Viral transcripts were detected in two nontumorigenic and in two tumorigenic cell lines.

ISSN:0300-5526    

DOI:10.1159/000150061

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Natural human interferons (IFN) and recombinant human IFNs (rIFN-α and rIFN-β) inhibited the production of virus in Chang’s human conjunctival cell cultures infected with epidemic isolates of acute hemorrhagic conjunctivitis virus, Coxsackievirus type A 24 (CA24). Generally, natural and rIFN-α and rIFN-β were equally effective in inhibiting CA24 infection. However, rIFN-α A was more effective than rIFN-α C, D, I, J, and K in reducing virus infection, cytopathogenesis, and virus production. Recombinant IFN-α J was least effective in inhibiting CA24 in human conjunctival cell cultures. Also, the IFN titer was reduced 10- to 1,000-fold when cells were infected with ≧ 0.3–0.5 CA24/cell, suggesting a dose-dependent IFN resistance by CA24. These results suggest that the antiviral activity of IFN against acute hemorrhagic conjunctivitis in vivo may vary with the CA24 isolates, the MOI, the type of IFN, and the time of infection with respect to beginning I

ISSN:0300-5526    

DOI:10.1159/000150062

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The effects of reagents that stimulate the intracellular level of cyclic AMP (cAMP), and of a tumor promoter, on polyomavirus (Py) DNA replication were examined in a Py-transformed rat cell line, designated the LPT line. cAMP-stimulating reagents (forskolin and 3-isobutyl-1-methyl xanthine) were found to induce replication of Py DNA in normally growing LPT cells and to enhance replication of the viral DNA in cells exposed to suboptimal doses of UV light and mitomycin C (which have been previously shown to induce Py DNA replication in LPT cells). The tumor promoter 12-O-tetradecanoyl phorbol-13-acetate did not cause a significant induction in Py DNA replication when it was applied to the cells alone, but enhanced replication of the viral DNA when it was applied together with the cAMP-stimulating reagents. Cycloheximide, an inhibitor of protein synthesis, was found to inhibit the induction of Py DNA replication by the cAMP-stimulating reagents. Based on these data, and on previous studies of the Py enhancer, it is proposed that cAMP may induce synthesis of an enhancer-binding protein that causes Py DNA replication in LPT cells by binding and activating an enhancer element which is a component of the Py origin.

ISSN:0300-5526    

DOI:10.1159/000150063

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Rabbit, horse, rat, and chicken immunoglobulin G (IgG); rabbit, horse, and goat IgG Fc fragments; rabbit and chicken F(ab’)2 fragments, and rat and chicken gamma globulins, in concentrations of 5 and 10 mg/ml, were able to reduce virus production 10- to 10,000-fold when incubated with herpes simplex virus type 1 (HSV-1)-infected GMK AH1 cells. When the ability of the purified IgGs and gamma globulins to interact with the HSV-induced Fc receptor on infected GMK cells was tested, only rabbit IgG and IgG Fc fragments from rabbit and goat were reactive. Thus, there was no correlation between the ability to interact with the HSV Fc receptor and the ability to inhibit viral growth. The ability of IgGs and gamma globulins to reduce HSV production is, therefore, not likely to be mediated by the HSV Fc recepto

ISSN:0300-5526    

DOI:10.1159/000150064

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Human embryonic lung (HEL) fibroblasts infected with simian cytomegalovirus (SCMV) were found to bind nonspecifically to the Fc portion of human immunoglobulin (Ig) G (IgG). Binding of IgG to SCMV-infected HEL fibroblasts, but not to uninfected HEL cells, was visualized as cytoplasmic fluorescence by the indirect immunofluorescence test, regardless of the presence of anti-CMV antibodies. The receptor(s) reacted with the IgG class of different species, but not with IgM and IgA. The purified Fc fragment reacted with the receptor(s), but the Fab fragment reacted poorly. The reaction was blocked by pretreatment of infected cells with the Fc fragment, but was not blocked with the Fab fragment. The appearance of the Fc receptor (s) required RNA and protein synthesis, whereas a requirement for DNA synthesis remains to be answered by a more sensitive assay. The development of the Fc receptor(s) was inhibited by 2-deoxy-D-glucose, thus indicating that the Fc receptor(s) may be a glycoprotein(s). The Fc receptor (s) was induced by all strains of SCMV tested so far. These included one laboratory strain (GR2757), four fresh isolates from primary kidney cell cultures of African green monkeys, and four fresh isolates from the salivary glands of the Macaca monkeys captured from the wild in Japan.

ISSN:0300-5526    

DOI:10.1159/000150065

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Eight reference strains of the nine accepted bovine adenovirus serotypes were compared by means of restriction enzyme (RE) analysis of the viral DNA. The study was carried out with the aim to identify RE giving restriction patterns which are particularly feasible for identification of new isolates and useful for their classification into subgroups. The BamHl, EcoRl, Hindlll and Pstl enzymes were feasible for identification of strains. The classification of bovine adenovirus (BAV) into subgroup 1 (BAV-1,2, 3 and 9) and subgroup 2 (BAV-4, 5, 6, 7 and 8) was supported by (i) the significant difference in genome size between members of subgroup 1 (ranging from 32.73 to 37.67 kb) and members of subgroup 2 (ranging from 28.78 to 31.18 kb); and (ii) the observation that the nucleotide sequence recognized by EcoRl is less frequent in the genomes of subgroup 1 members – yielding 4–7 RE fragments -than in the genomes of subgroup 2 members – yielding 10–16 RE fr

ISSN:0300-5526    

DOI:10.1159/000150066

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150067

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150068

出版商:S. Karger AG    

年代:1988

数据来源: Karger

ISSN:0300-5526    

DOI:10.1159/000150059

出版商:S. Karger AG    

年代:1988

数据来源: Karger