Purification and properties of an intranuclear virus-specific antigen from tissue infected with Borna disease virus.
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A virus-specific antigen was extracted from brains of rats and from MDCK cells infected with Borna disease (BD) virus and purified to homogeneity by immunoaffinity chromatography and HPLC. The antigen consists of two components which are almost equal in size (38 000 mol. wt.), and it forms aggregates in its native form. The virus specificity of the two antigenic entities was confirmed by immunoblots with convalescent serum and monoclonal antibodies. Immunofluorescent staining with monoclonal antibodies and a hyperimmune serum prepared against the purified antigen showed the intranuclear fluorescence typical for BD virus-infected cells. (+info)
Pathogenicity and persistence of pleural effusion disease virus isolates in rabbits.
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Nine isolates of pleural effusion disease agent or virus (PEDV) from treponema-infected rabbits in various countries were examined for pathogenicity and persistence in rabbits. The isolates showed a wide range of pathogenicity and were categorized into three groups according to the severity of the acute infection. Group 1 comprised isolates causing more than 50% mortality, group 2 isolates causing mortality below 50%, while group 3 comprised isolates causing almost subclinical infections. The range between group 1 and group 3 was similar to that observed with virulent and avirulent progeny of the original PEDV isolate. Infection by each of the nine isolates resulted in a chronic low level viraemia which persisted for up to 2 years or more. Viral progeny of pathogenic isolates obtained in serum after the 2nd month of infection failed to induce clinical disease on rabbit inoculation. The chronic, subclinical infection was associated with a moderate, continued increase in serum IgG, but circulating immune complexes could not be demonstrated. Two years after infection slight histopathological changes were present in lymph nodes, spleen, liver, heart and lung. Evidence of immune complex disease could not be demonstrated. (+info)
Effect of Borna disease virus infection on athymic rats.
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Homozygous athymic nude rats (rnu/rnu) infected intracerebrally with Borna disease virus produced relatively high titres of infectious virus in the central nervous system. However, no clinical signs of disease or pathological alterations could be found during a 100 day observation period. In contrast, heterozygous euthymic albino littermates (rnu/+), which were used as controls, reacted in a similar manner to immunocompetent Lewis rats. They developed behavioural alterations which coincided with encephalitis and retinitis. The results obtained confirm our previous concept that the genesis of Borna disease, at least in rats, is attributed to a cellular immune response. (+info)
Isolation and characterization of a 14500 molecular weight protein from brains and tissue cultures persistently infected with borna disease virus.
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A protein with an apparent molecular weight of 14500 (14.5K) was extractable from homogenates of Borna disease virus-infected brains and tissue cultures using high concentrations of detergent and salt and by differential centrifugation procedures. The protein, present in an aggregated form, was remarkably resistant to proteinase K. Specific antibodies prepared in the homologous system (rat) recognized the 14.5K protein from various sources (infected brain of rat, mouse or chicken, and tissue cultures), but did not neutralize infectivity nor stain Borna disease virus-specific antigens from in vitro or in vivo preparations. Post-infection immune sera from different animal species did not detect the protein. This 14.5K protein was infection-specific but not disease-specific, and is inferred to be part of an internal virion component. (+info)
Serotypes of bovine astrovirus.
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Three isolates of bovine astrovirus, one from the United Kingdom and two from the United States, possessed common antigens by immunofluorescence and strain-specific antigens by neutralization and were designated as two, and probably three, distinct serotypes. The isolate US2, despite being a different serotype, possessed the same restrictive cell tropism and cytopathology as previously reported for isolate US1, of the M cells of the dome epithelium of the Peyer's patches. Serotyping of 16 field isolates indicated the presence of more undefined serotypes. (+info)
Diagnosis of rotavirus infection by cell culture.
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Rotaviruses were detected by electronmicroscopy in 35 of 84 specimens of faeces from infants with diarrhoea, and in 31 by fluorescent staining of tissue cultures infected with help of centrifugation. LLC-MK2 cells were found to be the most sensitive, although primary and secondary human-embryo-kidney and primary calf-kidney cells could also be used. A micromodification of the tissue-culture method provides a relatively simple technique for the diagnosis of rotavirus infection, for the titration of virus infectivity and for estimating neutralising antibodies in serum. (+info)
Complement-fixing antibody response to rotavirus infection.
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A human rotavirus complement-fixing (CF) antigen, prepared by purification of large volumes of fluid feces collected from children with winter diarrhea, was used to study the development and persistence of antibody in children with diarrhea and the prevalence of rotavirus antibody in Melbourne. In children with diarrhea, antibody rises were detectable within 4 to 6 weeks of the onset of illness, and the titers usually remained elevated for the next 1 to 2 years. CF antibody did not develop in two children with proven rotavirus infection aged less than 6 months, an age at which poor CF responses to other viruses have also been observed. A study of CF antibody levels in the general community showed that in Melbourne, most children have been infected with human rotavirus by the age of 3 years. (+info)
Comparison of Counterimmunoelectrophoresis and electron microscopy for laboratory diagnosis of human reovirus-like agent-associated infantile gastroenteritis.
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Counterimmunoelectrophoresis was compared with electron microscopy for detection of human reovirus-like agent in fecal specimens. Both tests gave very similar results. (+info)