中文摘要：

通过RT-PCR方法从新城疫Ⅰ系疫苗诱导的11日龄鸡胚脾脏细胞中扩增出鸡白细胞介素18（Chicken interleukin-18，ChIL-18）成熟蛋白基因的cDNA，并将其克隆到pMD18-T载体上。DNA序列测定表明，克隆得到ChIL-18全基因，其编码区大小为597bp，编码198个氨基酸多肽。将该基因片段克隆到原核表达载体pProEXTMHTb构建重组质粒pProEX^TM HTb—ChIL-18转化大肠杆菌DH5a中，并用IPTG诱导。重组菌菌体裂解物SDS—PAGE可检测到相对分子量为28．6ku的重组蛋白。观察ChIL-18蛋白对新城疫疫苗诱导的HI抗体动态变化。结果表明，同时接种ChIL-18蛋白和活疫苗的免疫鸡在接种后，所产生的HI抗体效价高于PBS和活疫苗免疫组，并且，HI抗体效价在15d及热应激24h时表现差异显著（P〈0．05）。表明ChIL—18蛋白对新城疫疫苗诱导的HI抗体有增强作用。

英文摘要：

Chicken interleukin-18（ChIL-18） mature protein gene was amplified from spleen cells of chicken embryo which were induced by New casltle disease virues by RT-PCR. PCR product was cloned into pMD18-T vector. Sequencing analysis showed that the nucleotide sequence of this ChIL-18 mature protein gene was 597 bp, pProEXTMHTb-ChIL-18 was obtained by subcloning the encodeing region of the ChIL-18 mature protein gene into pProEXTMHTb. The recombinant ChIL-18 （rChIL-18） was expressed efficiently in pProEX^TM HTb-ChIL-18 transformed DH5α induced by IPTG. SDS-PAGE analysis showed that the recombinant mature protein had a relative molecular mass of approx in ately 28.6 ku. The effects of the ChIL-18 protein on Newcastle disease vaccine were observed by the kinetic changes of HI antibody. The results showed that ChIL-18 protein could enhance the valence of HI antibody.