Capucci L, Fallacara F, Grazioli S, Lavazza A, Pacciarini M L, Brocchi E
Department of Biotechnology, Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia, Brescia, Italy.
Virus Res. 1998 Nov;58(1-2):115-26. doi: 10.1016/s0168-1702(98)00106-3.
Rabbit hemorrhagic disease virus (RHDV) is a noncultivable calicivirus that infects rabbits (Oryctolagus cuniculus) and causes epidemics of an acute fatal hepatitis. In 1997 we identified two RHDV isolates from geographically distant Italian regions, which differed antigenically from the reference strain RHDV.Bs89. In fact, they were not reactive with mAb 1H8, that is able to protect rabbits from RHD and showed a low reactivity with the rabbit convalescent serum raised against RHDV.Bs89. Experimental infection of rabbits with either RHDV isolates confirmed their high pathogenicity and their peculiar antigenic profile; nevertheless, rabbits vaccinated with the current vaccine were protected against challenge infection with these isolates. Sequence comparison definitely demonstrated that the two isolates originated from the same RHDV variant and that the similarity of their structural protein (VP60) sequences with the RHDV.Bs89 is equal to 93%. This variant was named RHDVa since shows consistent genetic and antigenic differences from the wild-type RHDV. In particular, 44% of amino acid substitutions in RHDVa VP60 were located between amino acids 344 and 370, where the similarity with RHDV.Bs89 drops to 70%, suggesting that this region probably contains the epitope recognized by mAb 1H8. In addition, this paper presents preliminary data concerning the amino acids of VP60 involved in the hemagglutination site of the virus.
兔出血症病毒（RHDV）是一种不可培养的杯状病毒，可感染家兔（穴兔）并引发急性致命性肝炎的流行。1997年，我们从意大利地理上相距遥远的地区鉴定出两株RHDV分离株，它们在抗原性上与参考毒株RHDV.Bs89不同。事实上，它们与单克隆抗体1H8不发生反应，1H8能够保护家兔免受RHDV感染，并且与针对RHDV.Bs89产生的兔恢复期血清反应性较低。用任一RHDV分离株对家兔进行实验性感染，证实了它们的高致病性和独特的抗原特性；然而，用当前疫苗接种的家兔对这些分离株的攻击感染具有抵抗力。序列比较明确表明，这两株分离株源自同一RHDV变异株，并且它们的结构蛋白（VP60）序列与RHDV.Bs89的相似性为93%。由于该变异株与野生型RHDV存在一致的遗传和抗原差异，因此被命名为RHDVa。特别是，RHDVa VP60中44%的氨基酸替换位于氨基酸344至370之间，与RHDV.Bs89的相似性降至70%，这表明该区域可能包含被单克隆抗体1H8识别的表位。此外，本文还提供了有关病毒血凝位点所涉及的VP60氨基酸的初步数据。
