摘要:

Unique virus-like tubulofilamentous particles, termed nemavirus, have been consistently observed in spongiform encephalopathic brains by electron microscopy in thin sections. Sodium dodecyl sulphate treatment of unfixed infected brain tissue on grids revealed a twisted fibril core of tubulofilamentous particles. The unmasked fibrils were identified as scrapie-associated fibrils by immunogold labelling. Both tubulofilamentous particles and scrapie-associated fibrils are not artefacts of protease treatment of protein formed in vitro during purification. Treatment with protease and nucleases revealed that each tubule consists of three layers: (i) an outer coat of protease-sensitive material; (ii) an intermediate layer that is digested by DNase and mung bean nuclease, and (iii) inner protease-resistant protein scrapie-associated fibril.

ISSN:0300-5526    

DOI:10.1159/000150316

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

An enzyme-linked immunosorbent assay (ELISA) which uses a recombinant truncated form of the Epstein-Barr virus (EBV) membrane antigen gp350/250 has been developed and used to measure human IgA antibody responses to that antigen. From comparisons with conventional immunofluorescence assays (IFA) for measuring IgA antibody responses to EBV viral capsid antigens, the ELISA shows comparable specificity and is approximately 4-fold more sensitive. Since IgA antibodies to EBV indicate a high risk of developing nasopharyngeal carcinoma (NPC), the described ELISA, which is more sensitive and objective than IFA, has potential for use in the diagnosis of NPC and for large-scale screening to identify individuals at risk for the development of this disease.

ISSN:0300-5526    

DOI:10.1159/000150317

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

This study has examined different methods of preparation of a subunit vaccine from cytomegalovirus (CMV)-infected MRC cells in terms of protein and DNA content, antigenicity and immunogenicity. Two preparations have been developed where CMV proteins were obtained by extraction of infected cells with water. Virus particles were removed from the preparations by ultracentrifugation and residual virus was inactivated by formaldehyde in the WUF preparations or by chloroform in the WUCh preparations. The preparations contained CMV proteins which may play a role in protective immune responses, and the preparations were antigenic as determined by immunodiffusion, ELISA and immunoblotting. Immunogenicity as evaluated in rabbits indicated that the preparations stimulated neutralizing and immunoprecipitating antibody. These results suggest that the gentle method of water extraction of viral antigens may be a useful protocol for vaccine preparation.

ISSN:0300-5526    

DOI:10.1159/000150318

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

The complete DNA nucleotide sequence of a Hindlll/Mlul genomic DNA fragment (0.045-0.075 viral map units) from molluscum contagiosum virus type 1 (MCV-1) was determined. The Hindlll/Mlul DNA fragment comprises 5,646 bp with a base composition of 64.4% G + C and 35.6% A + T. The DNA sequence contains many perfect direct repeats. A cluster of three repetitive DNA elements Rl, R2 and R3, with a complex structural arrangement was detected between nucleotide positions 1802 and 2107. The unit length (box) of the repetitive DNA sequences was found to be 6 bp (15 boxes) and 9 bp (24 boxes) for Rl and R2, respectively. The repetitive DNA element R3 is organized in fifteen boxes (15 bp) in which a unit length of Rl is combined with a unit length of R2. The arrangement of the repetition R3 within the DNA sequences of this particular region of the MCV-1 genome was found to be (5 × R3) + (2 × R2) + (1 × R3) + (6 × R2) + (1 × R3) + (1 × R2) + (8 × R3). Twenty-three open reading frames (ORFs) of 60-1,175 amino acid (AA) residues were detected. The largest ORF (number 17) comprises 1,175 AA with a predicted molecular weight of 126 kD. This ORF harbors a promoter signal which is located 21 nucleotides upstream from the start codon and is very similar to the early promoter signals known for vaccinia virus. This putative protein contains glutamine-enriched regions between AA residues 427 and 682 which show homologies to the corresponding glutamine-enriched regions of a variety of cellular genes like human transcriptional initiation factor (TFIID: TATA box f

ISSN:0300-5526    

DOI:10.1159/000150319

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

We have studied the effect of gamma-interferon (IFN-γ) treatment on the transcription of viral and c-myc oncogenes in bovine papillomavirus type 1 (BPV-1)-transformed mouse fibroblast cell lines. Upon IFN-γ treatment, viral transcripts always decreased in cell lines containing episomal BPV-1 DNA, while the effect was variable in cell lines containing integrated BPV-1 DNA. Two series of tumour cell lines established by in vivo passage of B6B71 (episomal) and B6B31-J (integrated) cells via nude mice (NuTu A) into immunocompetent C57BL/6 mice (NuTuA B6Tu1) also showed a decrease and an increase, respectively, in viral transcripts upon IFN-γ treatment. IFN-γ also reduced c-myc transcription in all cell lines derived from tumours, but increased it in the transformed cell cultures. There was selection of c-myc oncogene transcripts in all the tumour-derived cell lines as compared to their transformed cell cultures. Cycloheximide treatment increased both viral and c-myc gene transcripts 3- to 20-fold in all cell lines. These results imply that IFN-γ produced locally by immunological mechanisms may influence the expression of Papillomavirus oncogenes, and the response to IFN-γ treatment may change when the viral DNA is integrated into the host g

ISSN:0300-5526    

DOI:10.1159/000150320

出版商:S. Karger AG    

年代:1993

数据来源: Karger

摘要:

An outbreak of echovirus type 30, primarily affecting infant under 1 year old, was documented in Nassau County, N.Y., USA. Twenty-four of the 40 infected patients were definitively diagnosed with aseptic meningitis. A positive correlation was found between the proportion of polymorphonuclear leukocytes and the overall cerebrospinal fluid white cell count.

ISSN:0300-5526    

DOI:10.1159/000150321

出版商:S. Karger AG    

年代:1993

数据来源: Karger