Saijo K, Higashihara M, Fujisaki Y, Matumoto M
Research Center for Veterinary Science, Kitasato Institute, Chiba, Japan.
Vet Microbiol. 1990 Apr;22(2-3):171-8. doi: 10.1016/0378-1135(90)90104-4.
Attenuated plaque variants were obtained from infectious bursal disease virus adapted to chick embryo cell cultures. The large plaque (Lp) clone and the small plaque (Sp) clone formed homogeneous plaques about 5 and 1 mm in diameter, respectively. Neutralization tests indicated that these clones differed little from their parent strain in antigenicity. Sp clones showed a retarded growth rate in chick embryo cell cultures as compared with Lp clones. The clones were significantly less pathogenic for chick embryos than the parent strain, although Lp clones were more pathogenic than Sp clones, and they were much less pathogenic for 1-day-old chicks and 28-day-old chickens. Both clones had immunizing potency in 28-day-old chickens, although the Lp clone had a somewhat higher potency than the Sp clone. These findings suggest the Lp and Sp clones, in particular the Lp clones, to be useful as live virus vaccine strains.
减毒斑块变体是从适应鸡胚细胞培养的传染性法氏囊病病毒中获得的。大斑块（Lp）克隆和小斑块（Sp）克隆分别形成了直径约为5毫米和1毫米的均匀斑块。中和试验表明，这些克隆在抗原性上与其亲本毒株差异不大。与Lp克隆相比，Sp克隆在鸡胚细胞培养中的生长速度较慢。这些克隆对鸡胚的致病性明显低于亲本毒株，尽管Lp克隆比Sp克隆的致病性更强，而且它们对1日龄雏鸡和28日龄鸡的致病性要低得多。两种克隆在28日龄鸡中都具有免疫效力，尽管Lp克隆的效力略高于Sp克隆。这些发现表明Lp和Sp克隆，特别是Lp克隆，可用作活病毒疫苗株。
