An indirect immunofluorescence test for detection of serum antibodies specific for nephropathia epidemica (NE) has been developed with use of acetone-fixed cryostat sections of the lungs of bank voles (Clethrionomys glareolus) that had been trapped from the NE-endemic area in Finland as antigen. NE antigen was detected as distinct fluorescence in the cytoplasm of alveolar and macrophage-like cells. The 16 patients studied included typical cases from an endemic area, cases from a family outbreak, and cases in a laboratory staff which had had close contact with infected bank voles. Antibodies reacting with antigen in the lung sections developed in all of the patients but they were not found in the preimmune sera of the patients, in the sera of patients with other renal diseases, or in the sera of healthy individuals, with the exception of a member of the laboratory staff who had lived in the endemic area for 20 years. No specific IgM antibodies to NE could be detected. The rise in titer of antibodies to NE was characteristically prolonged, and elevated antibody levels persisted for many years.
Temperature-sensitive mutants of Semliki Forest virus (SFV) and Sindbis virus (SIN) were used to study the intracellular transport of virus membrane glycoproteins in infected chicken embryo fibroblasts . When antisera against purified glycoproteins and '25 1-labeled protein A from Staphylococcus aureus were used, only small amounts of virus glycoproteins were detected at the surface of SFV is-1 and SIN Ts-10 infected cells incubated at the restrictive temperature (39°C) . When the mutant-infected cells were shifted to the permissive temperature (28°C), in the presence of cycloheximide, increasing amounts of virus glycoproteins appeared at the cell surface from 20 to 80 min after the shift. Both monensin (10p,M) and carbonylcyanidep-trifluoromethoxyphenylhydrazone (FCCP; 10-20 ,AM) inhibited the appearance of virus membrane glycoproteins at the cell surface. Vinblastine sulfate (10 jug/ml) inhibited the transport by^-50%, whereas cytochalasin B (1 l-Ag/ml) had only a marginal effect .Intracellular distribution of virus glycoproteins in the mutant-infected cells was visualized in double-fluorescence studies using lectins as markers for endoplasmic reticulum and Golgi apparatus. At 39°C, the virus membrane glycoproteins were located at the endoplasmic reticulum, whereas after shift to 28°C, a bright juxtanuclear reticular fluorescence was seen in the location of the Golgi apparatus. In the presence of monensin, the virus glycoproteins could migrate to the Golgi apparatus, although transport to the cell surface did not take place. When the shift was carried out in the presence of FCCP, negligible fluorescence was seen in the Golgi apparatus and the glycoproteins apparently remained in the rough endoplasmic reticulum . A rapid inhibition in the accumulation of virus glycoproteins at the cell surface was obtained when FCCP was added during the active transport period, whereas with monensin there was a delay of -10 min . These results suggest a similar intracellular pathway in the maturation of both plasma membrane and secretory glycoproteins.
The age-specific prevalence of CF antibodies against 16 viral antigens was determined by using the computerized data registry of the routine diagnostic laboratory of the authors' department. The material consisted of data based on serum specimens from about 58,500 patients. All ages from newborn infants to 90-year-olds were represented. The sera had been collected and tested with a CF screening test over a period of 8 years (1971-1978). Several different antibody prevalence patterns were distinguished in regard to the rapidity and timing of the initial increase of the prevalence, as well as to the mode of later changes in prevalence. For most respiratory viruses a rapid increase of the prevalence was seen through the childhood continuing, for some of them, up to the 30s (influenza A and coronavirus), while rather variable patterns were found in the older age groups. Herpes simplex and cytomegaloviruses showed, interestingly, another type of pattern: a slow increase of prevalence continuing through the whole age range. The frequency of herpes simplex antibodies reached 90% by the age of 80 years. Antibody levels against any antigen in infants less than one-month-old were equal to those in 20- to 40-year-old adults, and the expected rapid decrease of antibodies took place within the first 6 months of life. Possible influences of epidemics and repeated exposures to different viruses (external boosting), and of latent or chronic infections (internal boosting), as well as of technical variations, on the observed prevalence patterns are discussed.
Circulating immune complexes (CICs), immunoconglutinins, and antiglobulins were studied in nephropathia epidemica, an acute infectious hemorrhagic fever occurring in Finland and Scandinavia. Sixty-one serum specimens from 18 serologically confirmed patients were collected between day -5 and day 230 from the onset of fever. Five CIC tests, three immunoconglutinin tests, and various other tests were used to characterize the disease immunologically. CICs were found in all patients. The percentage detection of positive cases varied in the tests from 100% to 22%. A marked stimulation of levels of the IgM class of immunoglobulins were observed. Antiglobulin tests were positive for all of the patients. No correlation between the test results and the clinical severity of the disease could be found. Of special interest was the delay in the rise of CIC levels compared with the chromologic pattern of the clinical course. In some patients a prolonged appearance of CICs for eight months was observed.
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