Establishment and an Inoculation Test of an Attenuated Strain of Porcine Parvovirus by Serial Passage in Primary Swine Kidney Cells at Low Temperature

Abstract

The attenuated HT^- strain produced Fujisaki et al. was adapted to primary swine kidney (SK) cell culture by repeating passages at 32°C, treating by UV irradiation and heating. As a result, it was possible to establish a low-temperature-adapted HT^--SK-C strain, which showed a maximum growth at 32°C, without being contaminated with any other viruses.
The characterization of this strain was as follows. The infectivity titer at 32deg;C was 106.3 TCID50/ml in ESK cells. The TS marker of the strain was rct/37^-, rct/40^-, each EOG being estimated to be 4.3 and above 5.8. When this strain was shifted up to 37deg;C for 3 serial passages, the infectivity titer was under 10^1.0TCID₅₀/ml and EOG at 37deg;C estimated to be above 3.8. Five qineapigs were inoculated subcutaneously with 10^6.3TCID₅₀/ml of this strain. In them, HI titer was 80. 121 (GM) 4-5 weeks after and 8 weeks 92 after inoculation.