title: Persistence of tic-borne encephalitis virus in monkeys. III. Phenotypes of the persisting virus.
abstract: The properties of tick-borne encephalitis (TBE) virus persisting for 90-383 days after intracerebral and subcutaneous inoculation of Macaca rhesus monkeys were studied, namely (1) the type of infection produced directly in the tissues of the experimental monkeys; (2) the activating effect of co-cultivation and explantation procedures; and (3) the phenotype of the isolates by a set of markers. The virus was detected and analysed in 52 instances. Directly in monkey tissues the virus induced a productive infection rarely (5.8%) but more frequently (71.2%) an abortive infection detectable by immunofluorescence (presence of virus-specific antigen). In 23% of instances a nonproductive infection was observed in monkey tissues. Like abortive infection it could be activated by the co-cultivation of cells and explantation procedures. The latter exerted a more marked activating effect than co-cultivation. The strains isolated from monkey tissues in productive infection or activated by explanation or co-cultivation were heterogeneous in their properties. The following virus phenotypes were found: virus highly virulent for mice, cytocidal and antigenically complete; a cytocidal virus of low virulence, possessing haemagglutinin; and a cytocidal virus apathogenic for mice, devoid of haemagglutinin but synthesizing complement-fixing antigen and an antigen detectable by immunofluorescence.
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D002642:Chick Embryo; D003588:Cytopathogenic Effect, Viral; D004669:Encephalitis Viruses, Tick-Borne / Q000235:genetics* / Q000276:immunology; D004675:Encephalitis, Tick-Borne / Q000382:microbiology; D006389:Hemagglutinins, Viral / Q000032:analysis; D008251:Macaca / Q000382:microbiology*; D008253:Macaca mulatta / Q000382:microbiology*; D051379:Mice; D010641:Phenotype; D014775:Virus Activation; D014776:Virus Cultivation / Q000379:methods
chemical_list: D000956:Antigens, Viral; D006389:Hemagglutinins, Viral