Abstract: Newcastle disease is an infectious disease that must be controlled and eradicated in China. In order todays after immunization，the average HI titer of serum collected from rLa ?mGM inactivated vaccine and commercial LaSota vaccine was 7.6log2 and 7.4log2，respectively. These results indicates that the recombinant virus is immunogenic and can be used as a vaccine candidate strain. generate antigen ? matched vaccine，the main antigenic ? related fusion and hemagglutinin ? neuraminidase genes of LaSota vaccine strain were replaced by those genes of GM strain belonging to genotype Ⅶ，and the recombinant virus rLa ? mGM was obtained by virus rescue. Biological characteristics of rLa ? mGM showed that the MDT of the recombinant strain was 160 h，the ICPI was 0，and the EID50 was 10-8.4 /0.2 mL. The rLa?mGM strain was propagated to prepare an inactivated vaccine at 108.0 EID50 and immunized 10 SPF chickens of 25?day?old with 0.2 ml/each. At 14

Key words: Newcastle disease； Genotype Ⅶ ； LaSota vaccine strain； Recombinant strain； HI titer； Vaccine candidate strain

摘要： 新城疫是我国必须控制和净化的传染病之一，疫苗免疫是防控疾病的重要手段。 为获得抗原性匹配的疫苗株，以新城疫LaSota疫苗株为骨架，替换当前流行的基因Ⅶ型毒株 GM株的主要抗原性相关基因F（Fusion）和HN（Hemagglutinin?neuraminidase），拯救获得重组病 毒 rLa?mGM。生物学特性测定表明，重组毒株的 MDT 为 160 h，ICPI 为 0，EID50为 10-8.4 /0.2 mL。将rLa?mGM株繁殖后以108.0 EID50制备灭活疫苗，与商品化LaSota疫苗各免疫10只25日 龄SPF鸡，0.2 mL/只。免疫后14天，其血清平均HI效价为7.6log2，商品化LaSota疫苗免疫鸡 的血清平均HI效价为7.4log2。结果表明重组病毒免疫原性良好，可作为疫苗候选株。

关键词: 新城疫； 基因Ⅶ型； LaSota疫苗株； 重组毒株； HI效价； 疫苗候选株