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Biomedical subjects

H G Purchase

Publications and source records attributed to H G Purchase.

At least 55 records · Page 3Linked to original sources
PubMed1971

Pathogenicity and Antigenicity of Clones from Strains of Marek's Disease Virus and the Herpesvirus of Turkeys.

Virus was extracted by filtration from chicken embryo fibroblast cultures infected with the JM, high passage JM(JMHP), GA, and RPL39 strains of Marek's disease virus (MDV) and from the herpesvirus of turkeys (HVT) and purified by cloning. The plaques produced by clones of HVT, JMHP, and other MDV strains differed in morphology from one another. Clones of MDV varied greatly in pathogenicity for chickens, but JMHP and HVT were nonpathogenic. Two pathogenic clones of JM virus and a clone of JMHP virus lacked the A precipitin antigen present in all other clones tested. All clones had at least one B antigen in common. HVT and MDV clones with and without the A precipitin antigen could be distinguished from each other by the indirect fluorescent antibody test. Changes in virus-host cell relationships, loss of pathogenicity, and loss of the A antigens were independent events.

Journal Article↗
PubMed1970

Combined fluorescent-antibody and electron microscopy study of Marek's disease virus-infected cell culture.

Duck embryo fibroblast (DEF) and chicken embryo fibroblast (CEF) cultures infected with Marek's disease virus were studied by combined fluorescent antibody and electron microscopy techniques. In both DEF and CEF cultures, cells containing immunofluorescent (IF) antigen also contained herpesvirus particles; conversely, cells lacking this antigen lacked herpesvirus particles. Two morphologically distinct IF antigens were detected in the cytoplasm. (i) A granular antigen in the perinuclear region was brightly stained with the conjugated antibody. This antigen was composed of a granular mass of osmiophilic material and did not contain virions. (ii) A diffuse antigen, present throughout the cytoplasm of infected cells, was less brightly stained. The area of the cell with the highest concentration of this antigen contained small vesicles, folded membranes, and fine electron-dense granules. Naked virions were occasionally seen in these areas. A diffuse nuclear IF antigen was occasionally seen in infected cells. This antigen was often separated from the nuclear membrane and the nucleolus by a clear margin. The intranuclear IF antigen was composed of a fine granular aggregate and naked herpesvirus particles which were randomly distributed throughout the nucleus. Viral capsids in antibody-treated cells were coated with fine filamentous material.

Animals↗
PubMed1969

Immunofluorescence in the study of Marek's disease. I. Detection of antigen in cell culture and an antigenic comparison of eight isolates.

The indirect fluorescent-antibody (FA) test was applied to the detection of Marek's disease (MD) antigen in cell culture and antibody in the serum of birds. For the detection of antigen, sera were obtained from birds hyperimmunized with the JM strain of MD. MD antigen could be detected in the nucleus and in the cytoplasm of duck and chick embryo fibroblasts and in those of chick kidney cells infected with material known to contain the MD virus. Uninoculated cultures of chicken cells were always free of MD antigen. When chick kidney cells were infected with a stock cellular preparation of MD virus, infected cells could be detected after 24 hr with the FA test. At this time no cytopathological areas were seen by conventional light microscopy. By 7 days after infection, the same number of infected areas were detected by both methods, and the fluorescent areas coincided with the cytopathological areas. This indicates that the fluorescent areas and the areas with cytopathology are caused by the same agent. A straight-line relationship between the dilution of inoculum and the number of fluorescent or morphological foci obtained indicates that one infectious unit produced one fluorescent or morphological focus. In addition, this time sequence study confirmed the cell association of the virus and demonstrated the cell-to-cell spread of infection. Cell cultures inoculated with eight different isolates of MD were tested in all combinations with sera prepared against the same isolates. The antigens were indistinguishable from one another, indicating that either the strains are antigenically identical or there is a common antigen or contaminant in all of them so that they stained equally well. The FA test can detect MD antigen before cytopathological areas develop in cell culture; however, the small size of the area usually examined precludes its use in initial isolations in which only a small number of infectious units are present in the inoculum. MD-infected cells contain a heat-stable antigen similar to that found in herpes simplex-infected cells.

Animals↗