Abstract
The replication of feline panleukopenia virus (FPLV) in the synchronized kitten kidney (KK) cells was studied. The adsorption rates of [3H]-thymidine-labeled FPLV to each of the G1, early S and M phases of cell cycle were almost the same. The KK cells maintained in the G1 phase did not support the replication of FPLV through the 12 to 36 hours of the observation period. However, when the cell cycle was allowed to proceed by trypsinizing G1 phase cells at 0, 6 and 12 hours after virus infection, a slight replication of the virus was observed. A high replication of FPLV was obtained from the cells infected at early S phase. The early S phase cells arrested with 2mM thymidine (TdR) also supported well the growth of FPLV when the initiation of the cell cycle was performed by the removal of TdR within 12 hours after infection, early S phase arrested cells themselves did not. No replication of FPLV was observed in the M phase cells. These results indicate that FPLV requires the DNA synthesizing system of KK cells for its replication.
