[Further study of the leukocyte virus isolated in hepatitis A]

Two strains of leukocyte hepatitis virus (LHV) which had undergone 13 and 16 passages, respectively, in phytohemagglutinin-stimulated cultures of leukocytes from normal donors were studied in experiments with labelled precursors (3H-uridine and 14C-amino acids). The buoyant density of the virus (1,26 g/ml) and sedimentation constant of RNA (46 S) were determined. LHV was shown to be capable of reproduction in human kidney cell culture. The immunofluorescence test could be used with labeled convalescent sera for examinations of blood smears from patients for diagnosis of hepatitis A in foci of infection. In these tests, fluorescence was detected in the cytoplasm of lymphocytes and granulocytes but not in the nucleus. The immunofluorescence test with convalescent sera was successfully used for the examinations of smears of cultures of PHA-stimulated leukocytes of normal donors infected with LHV in order to prove the specificity of this virus in hepatitis A.