| Abstract: | Human papovavirus JC virus was adapted to growth in human embryonic kidney (HEK) cells. After eight passages, the HEK-adapted JC virus produced high virus yields and was capable of forming plaques in HEK monolayer cultures. Eleven plaque-purified stocks were prepared and characterized. Biologically, the plaque-purified virus induced tumor and viral antigens in HEK cells earlier and in a higher percentage of cells than uncloned virus. Cytopathic changes were also evident sooner and were more extensive. The DNA from uncloned as well as plaque-purified isolates was analyzed by restriction endonuclease cleavage followed by gel electrophoresis. The DNA from uncloned HEK-adapted virus was heterogeneous. Plaque-purified virus isolates yielded DNA which, although much less heterogeneous than the uncloned stock, still consisted of two or more species of viral DNA. |
