PATHOGENICITY AND IMMUNOGENICITY FOR SOME RABBIT HEMORRHAGIC DISEASE VIRUS(RHDV) STRAINS PROPAGATED IN ISOLATED HEPATOCYTES OF RABBIT

The hepatocytes were isolated from the liver of different week-age of healthy rabbits by a single two-stage pass perfusion method and suspended in Hanks’ balanced salt solution (Ca[Formula: see text]-, Mg[Formula: see text]-free). The field strains of RHDV were inoculated into the suspension and incubated for 2 days at 37∘C. After incubation, the HA titer of each strain of RHDV in supernatant of virus growth was measured using human erythrocyte O type. There were differences in the HA titers of RHDV strains according to the hepatocyte of different week-age of rabbits, the number of hepatocyte, the strain of virus (RHDV-1, RHDV-2, RHDV-3) and the duration of incubation. The HA titer was highest when the virus was cultured in the hepatocytes isolated from more than 12 week-aged rabbits. When non-immune rabbits were inoculated with the strains of virus (RHDV-1, RHDV-2, RHDV-3). respectively, all rabbits (3 heads of rabbit per group) infected with RHDV-1 and RHDV-3 died of the disease within 48[Formula: see text]h, while only one rabbit infected with RHDV-2 died within 72[Formula: see text]h. When immunized rabbits by inactivated virus strains (RHDV-1, RHDV-2 and RHDV-3), 2 strains, RHDV-1 and RHDV-3, showed the same level of HI titers with inactivated homogenate, but RHDV-2 did lower the level of titer than the homogenate.