摘要:

The successful application of an improved enzyme-linked immunosorbent assay (ELISA) to the specific detection and quantitation of feline leukemia virus (FeLV) is presented. The methods described can detect FeLV antigens at the picogram/milliliter level using a fluorometric assay for peroxidase-linked antibody. The use of a fluorogenic substrate resulted in at least a 9-fold increase in sensitivity of the peroxidase assay. FeLV antigens could be specifically detected in chronically infected cells as well as in feline sarcoma virus-transformed nonproducer mink cells which only partially express viral proteins.

ISSN:0300-5526    

DOI:10.1159/000149208

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

BK virus (BKV) DNA sequences were not detected in 142 human tumors analyzed by DNA-DNA reassociation kinetics and blot hybridization. The investigation was focused mainly on those rare types of human tumors (ependymomas, choroid plexus papillomas, tumors of pancreatic islets and osteosarcomas) that are induced with highest frequency by BKV in experimental animals. In addition, other tumors of the urinary apparatus and of the central nervous system were analyzed. BKV tumor (T) antigen was not detected in neoplastic tissues, and BKV T antibodies were not found in sera and cerebrospinal fluids from patients with neoplasms. Sequences homologous to BKV DNA were found in normal tissue from a kidney carrying a carcinoma. The neoplastic tissue from the same organ, however, had no sequences homologous to BKV DNA. Such DNA does not belong to BKV but probably to another papovavirus related to BKV.

ISSN:0300-5526    

DOI:10.1159/000149209

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Seven Australian infectious bronchitis viruses incorporated radioactive amino acid label during growth in two types of cell culture. From purified virions, four major polypeptides of molecular weights 91,000 (GP91), 51,000 (VP51), 25,000 (GP25) and 23,000 (VP23) were separated by PAGE. Two minor polypeptides of molecular weights 210,000 (GP210) and 185,000 (GP185) were also identified. 3H-glucosamine was incorporated during growth of virus into GP210, GP185, GP91 and GP25. Bromelain digestion of virions removed GP210, GP185 and GP91, leaving VP51, GP25 and VP23 in a large sub viral particle. All seven viruses, which were of six serological subtypes, formed apparently identical polypeptide profiles.

ISSN:0300-5526    

DOI:10.1159/000149210

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

98 antisera prepared against 25 simian adenoviruses and 31 adenovirus types from various nonprimate mammals and birds were tested for their ability to neutralize 35 human adenovirus prototypes. Antisera to these human adenovirus types were similarly tested against 25 simian adenovirus prototypes. Although very few reactions to the human adenoviruses were found in antisera to nonprimate viruses, cross-reactions among the simian and human adenoviruses were more frequent. The majority of these reactions, however, were of low titer and of questionable significance. Two chimpanzee adenovirus strains – Pan 9 and SAV 21 (C 1) – were found with an immunological relationship to human adenoviruses: Pan 9 strain showed a two-way cross relationship to human adenovirus 4, and SAV 21 (C 1) was neutralized by antisera prepared against human adenoviruses 14 and

ISSN:0300-5526    

DOI:10.1159/000149211

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Two distinct profiles of hexon end parts were detected in two-dimensional adenovirus hexon crystalline arrays: (i) hexons displaying three approximately oblong subunits around a triangular hole, and (ii) triangular hexons showing three main subunits with Y-shaped slits in their centers. The rest of the hexons seemed to be approximately ring-shaped with a roundish hole at their centers. Direct examination of electron micrographs and their optical diffraction patterns as well as Markham’s rotational integration technique permitted the establishment of the mutual orientation of hexons and of polypeptide subunits within small, distinct parts of the crystalline array. The position of the hexons is such that one of the polypeptide subunits of a given hexon is situated nearest to the two other polypeptides of the neighboring hexon (‘one-to-two’ linkage sy

ISSN:0300-5526    

DOI:10.1159/000149212

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Epstein-Barr virus (EBV) from P3HR-1 cells, but not from B95–8 cells, can induce the synthesis of thymidine kinase (TK) in TK-negative Raji cells. The synthesis of TK was slightly reduced, but not inhibited, when cells were cultivated in the presence of cytosine arabi-noside (ara-C). On the other hand, the synthesis of TK in ordinary Raji cells was enhanced in the presence of the drug. Thymine-β-D-arabinofuranoside (ara-T) was capable of reducing the conversion rate of thymidine to TdR nucleotides by extracts prepared from superinfected Raji TK-cells, but had no influence on TK activity in cell extracts from ordinary Raji cells and EBV-negative Ramos cells. This suggested a broader substrate specificity of the virally induced enzy

ISSN:0300-5526    

DOI:10.1159/000149213

出版商:S. Karger AG    

年代:1981

数据来源: Karger

摘要:

Exposure of several spontaneously transformed human lymphoid cell lines to attenuated and virulent types 1 and 2 poliovirus strains led to an initial sharp increase in virus titer followed by a persistent infection. Virus was present as late as 80 passages after infection. The morphology, cell count and viability of virus- and mock-infected cells were similar. Approximately 1 % of the cells scored as infectious centers, and the cultures could be cured by specific antiserum. Virus produced during persistent infections initiated with a virus that readily forms plaques at 40°, Mahoney virus, showed an increase in temperature sensitivity and a decrease in plaque size

ISSN:0300-5526    

DOI:10.1159/000149214

出版商:S. Karger AG    

年代:1981

数据来源: Karger