STUDIES ON THE MULTIPLICATION OF SIMIAN VIRUS 40 (VACUOLATING VIRUS) BY MEANS OF FLUORESCENT ANTIBODY TECHNIQUE

Abstract

Multiplication of simian virus 40 (SV 40) in African green monkey kidney cells was investigated by the fluorescent antibody technique. In both primary and continuous green monkey kidney cells, the specific antigen of SV 40 was first detected in the nucleus from one to two days after infection. The intranuclear antigen was observed as fluorescent granules of various sizes and its concentration reached the maximum from two to four days after infection. At that time the viral antigen could also be observed in the cytoplasm and the cytoplasmic vacuolization became observable in a small number of cells. This suggested that SV 40 was mainly synthesized in the nucleus and then transferred into the cytoplasm, giving rise to the vacuolization in the cytoplasm. The growth of SV 40 in continuous green monkey kidney cells was investigated in regard to the cell-associated virus and the fluid virus. The course of the appearance and increase of the specific viral antigen detectable by the fluorescent antibody technique paralleled the growth curves of infectious virus. Human continuous cell lines, FL, HEp-2 and HeLa-S3, supported the growth of SV 40. No cytopathic effect, however, could be observed in any culture, indicating a state of persistant infection. The ratio of the fluorescent cells to the total cells in the culture was usually proportionate to the infectivity of the culture fluid. The susceptibility of each cell line to SV 40 varied; FL and HEp-2 cells proved to be fairly susceptible, while HeLa-S3 cells were less susceptible. The state of persistant infection disappeared after serial subcultures of the infected culture. Cured cultures thus obtained did not resist a superinfection by the same virus.