ISSN:0300-5526    

DOI:10.1159/000149376

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Recombination analysis with 5 temperature-sensitive (ts) mutants of vaccinia virus, relegated to the E category phenotype and mimicking closely the effects produced by the antibiotic rifampicin, was undertaken to determine whether the genetic loci determining this phenotype were clustered on the genetic map. Optimum conditions for analysis were established with respect to the MOI and duration of incubation. At an MOI of 5–10, consistent values of recombination frequency (RF) were obtained, but became significantly lower when the MOI was 1 or less. Constant RF values were recorded when the duration of the infection was 8–24 h. These values were increased 3-fold by extending the incubation to 36 h. Under the standard conditions for analysis adopted, each mutant partner was added at an MOI of 10 and incubation was for 18 h. The map of group E mutants drawn from RF values obtained by 2-factor crosses was confirmed by 3-factor cross analysis, in which recombinants carried both the ts mutations and the rifampicin-resistance (R) marker. Both 2- and 3-factor cross data revealed that the 5 group E mutations were not clustered on the vaccinia virus genome. Surprisingly, after recombining ts 7743 with rifampicin resistance (R), different isolates of ts 11 A3 R could be mapped at two loci to the right or left of another isolate, ts 9383. Characterization of five independent plaque isolates of the progeny arising from a ts 11 A3 R parent showed that one isolate possessed a cold-sensitive phenotype (33°/40° = 1:26), two isolates retained their original ts character, and two became phenotypically like wild type (wt) with respect to thermosensitivity. However, upon segregation of the ts and R markers, one of the ‘wt’ isolates regained the original ts 11 A3 phenotype. These observations imply the occurrence of an interaction between the R and ts 11 A3 mutations, either directly at the level of genomic expression or during function of the relevant gene

ISSN:0300-5526    

DOI:10.1159/000149377

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The growth characteristics of Marituba virus, a member of the Bunyaviridae family, were studied in L-A9 cells. Virus yield was strictly dependent on the MOI. Quantitation of infectious virus released from the cells revealed a decrease in magnitude with continued serial passage. Specificity of the Marituba virus inhibitory response was investigated in relation to interference within homologous and heterologous viral classes. Virus particles were studied by isopycnic centrifugation in sucrose gradients. Under conditions of multiple viral passages at high multiplicity, two major classes of virus particles were produced, one band at 1.19 g/ml and another at 1.16 g/ml. Particles at 1.16 g/ml were noninfectious. Our results suggest that during the replication of Marituba virus at high MOI a population of defective interfering particles is generated.

ISSN:0300-5526    

DOI:10.1159/000149378

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Cytomegalovirus(CMV)-specific lymphocyte proliferation in vitro was tested in the presence or absence of CMV-specific antibodies. CMV antibodies clearly enhanced CMV-specific lymphocyte proliferation but not lymphocyte proliferation induced by other antigens. Enhancement was most consistently found with cell-bound CMV antigens and often with cell-free CMV as stimulating antigen. CMV antibodies only stimulated when they were added at an early stage of the lymphocyte culture, and the stimulating effect was most pronounced at optimal and suboptimal antigen concentrations. Our data suggest that CMV antibodies stimulate CMV-specific lymphocyte proliferation at the level of antigen presentation.

ISSN:0300-5526    

DOI:10.1159/000149379

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The varicella-zoster virus(VZV)-specific serum immunoglobulin A (IgA) response was studied in varicella and zoster patients and in healthy adults of various ages by a sensitive solid-phase radioimmunoassay technique. Significant rises in VZV-specific IgA titer were found for both varicella and zoster patients, while VZV-specific IgA was also detected in > 90% of healthy adults but at lower titers. No significant decrease in VZV-specific IgA titer with increasing age was found. The role of humoral versus cell-mediated immunity in VZV reactivation is discussed.

ISSN:0300-5526    

DOI:10.1159/000149380

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

A panel of 10 monoclonal antibodies raised to 3 different poliovirus type 1 strains was tested in a micro-enzyme-linked immunosorbent assay and in a micro-neutralization test against 87 poliovirus type 1 strains. The results, evaluated in a newly developed system for intratypic strain characterization, were compared with the results obtained with the classical serodifferentiation system by using a small number of strain-specific, cross-absorbed antisera. The new system not only uses results obtained with strain-specific antibody preparations, but also uses the information obtained with monoclonal antibodies reacting with less unique antigenic determinants. In a theoretical pattern fitting computer program, each virus strain could be compared with all the other strains for which serological data were stored in the memory of the computer. The results obtained with the new system coincided well with those obtained with the classical system: all except one of the strains classified as Sabin-like or intermediate in the classical system scored ‘perfect fit’ or ‘related’ with the Sabin 1 vaccine strain in the new system. Likewise, all virus isolates classified as Kuwait-like in the classical system scored ‘perfect fit’ or ‘related’ with the Dutch Kuwait-like isolate

ISSN:0300-5526    

DOI:10.1159/000149381

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The filamentous particles of cowpea mild mottle virus (CMMV) were detected only in the cytoplasm of palisade, mesophyll, parenchyma and epidermal cells of Glycine max (Papilionaceae) and Nicotiana develandii (Solanaceae). They were aggregated to form either sheets or bundles or, more frequently, brush-like inclusions. Although CMMV was initially considered to be a possible member of the Carlavirus group, it differs from aphid-borne carla-viruses in its intracellular occurrence and transmission by whiteflies and in being frequently seed-transmitted in some leguminous hosts. Because CMMV is also serologically unrelated to any of 12 recognized carlaviruses, we suggest that it now be removed from the carlavirus group and left unclassified until the taxonomic significance of these differences has been fully evaluated.

ISSN:0300-5526    

DOI:10.1159/000149382

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Marituba virus was purified by rate-zonal sedimentation and equilibrium density centrifugation in sucrose gradients. The buoyant density of virus particles was 1.19 g/ml. Purified virus was dissociated and its proteins were analyzed by SDS-PAGE. Four virus polypeptides were identified and designated L, Gl, G2 and N. Their average molecular weights were 190 × 103 [L, range (180–200) × 103], 120 × 103 [Gl, range (118–122) × 103], 26 × 103 [G2, range (24–28) × 103], and 20 × 103 [N, range (19–21) × 103]. Polypeptides N and L are, respectively, the major and the minor viral components. Gl and G2 are glycopeptides as demonstrated by the preferential incorporation of labeled 3

ISSN:0300-5526    

DOI:10.1159/000149383

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

To understand the prevalence and incidence of hepatitis A virus (HAV) infection in Chinese children in Taiwan, we determined the age-specific prevalence of hepatitis A antibodies (anti-HAV) in 823 children, ranging from birth (cord blood) to 19 years of age. The frequency of anti-HAV rose with increasing age with three different slopes, probably reflecting different age-specific incidences: lowest under 4 years of age, intermediate between 4 and 10 years, and highest above 10 years. We obtained follow-up specimens on 618 of the preschool children under 6 years of age. 11 (1.9%) of the 573 without antibodies had seroconversions after an average of 1.9 years of follow-up. The annual incidence was 1.0% and increased with advancing age of the children after infancy. None of the 11 seroconversions’had clinical hepatitis. Among the 28 children 1–24 months of age who had antibodies, only 1 was positive on follow-up, reflecting loss of passively acquired maternal antibody in most child

ISSN:0300-5526    

DOI:10.1159/000149384

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Incompatibility group C plasmid-specific bacteriophage C-1 has a buoyant density of 1.43 g/cm3, a sedimentation coefficient of 80–82S, and a molecular weight of 4 × 106. It contains approximately 33% nucleic acid, which has been identified as linear single-stranded RNA of molecular weight (1.3 ± 0.1) × 106. These characteristics, in conjunction with particle morphology and resistance to chloroform and diethyl ether, suggest that phage C-1 belongs to the Leviviridae group of ph

ISSN:0300-5526    

DOI:10.1159/000149385

出版商:S. Karger AG    

年代:1983

数据来源: Karger