Aujeszky's disease (Pseudorabies) occurred in southern Taiwan from June 1971 for 2 years, not only had not been controlled but also continually spread. Killed vaccine had been found to be inadequte for the protection of swine during natural outbreak. But many investigators paid more attention to the living vaccine. They had found that modified live vaccines were available for use in swine. So author tried to adapt the new isolated Pingtung strain in chicken-kidney (CK) cell cultures. The results were summarized as follows:
1. The Prv. Pingtung strain could be successfully adapted in CK cell after several passages of propagating the virus in PK-15 cell and CK cell culture by turns. Being passed 30 passages through CK cell culture. The CPE change was later than original virus (from 56一68 hrs. to 72-84 hrs.) and its virus titer (TCID50)rose to 105(Original vi- rus is 104 in CK cell).
2.The adapted virus pathogenicity to rabbit had been attenuated. when injected to abbits the infected dose (ID) was diminished to 103. (Original virus is 106．
3. The adapted virus growth curve in CK cell culture: Extracellular virus and Intracellular virus took the same curve, but Extracellular virus maintained longer and highter virus titer than Intracellular virus.
4. The adapted virus had extremely high immunity potency to SPF piglets and there were no ill post-vaccinated reactions such as thermal response, viremia observed, but neutralization antibody titer increased slowly. Its. pig infected dose (PID) reached to 105