[Cytogenetic characteristics of suckling mouse brain cell cultures, chronically infected with Japanese encephalitis virus].

The brain cells of the suckling mice line MSB-1-K-33 chronically infected by an attenuated variant of the Japanese encephalitis virus and of cell clones isolated from the later, had mainly a neartetraploid keryotype (the modal class 70-71 chromosomes). In metaphases of cloned cell populations, an increase of number of the chromosomes was especially obvious in clones 3 and 4 (modal classes in both cases were 76-77 chromosomes). Cell population of clone 1 differed insignificantly from that of the parental line MSB-1-K-33 in respect of its cytogenetic characteristics. In metaphases of the line MSB-1-K-33 and clones 1, 3, and 4, a high frequency of chromosomal damages was observed. The most frequent type of structural chromosome aberrations were chromatid breaks. The karyotypes of clones 3 and 4 were characterized by presence of a large marker metacentric chromosome in 50-53% of the cells. The data obtained suggest a continuous effect of the Japanese encephalitis virus on the karyotype of cells in infected culture.