Two isolates, N3 and T3 were cultivated in various cell cultures, and the infective ties of exta-cellular virus, intra-cellu)ar virus were determined in every other rericd of 5 days. From thc€e growth curves of the isolaal viruses, We have known the rtinent cell line cultures are PK-13 andESK. Virus titer reached 1O”7.O-7JTCIDSO,O.lmlat 12 to 24 hours tincti]atir*gin PK-13 cell line and 1&’7.0Z5 TCflJSO,0.lmlat 24 to 48 hours postinccu]ating in ESK cell line. Vinis titer reached around 10”6.3-6.? TCIDSO,O.lmlat24 to%hours pastnccWathgmPK-l5, MEEK, BK, MK2and KB cell lines.
The ethogenicity of the two isolates were weakened for rabbit after 20 subssages inPK-13 and ESK