CpG ODN增强猪囊尾蚴病疫苗免疫反应的试验研究

Experimental studies on CpG oligodeoxynucleotide enhancing immune responses of the cysticercosis cellulosae vaccine to animals

依据CpG基序的生物学和免疫学特性 ,人工设计合成了硫代修饰的多种CpGODN序列 ,通过兔、小鼠和猪体进行了与铝胶、2 0 6佐剂和蜂胶佐剂的配伍和比较试验 ,用ELISA法测定加单一佐剂或联合佐剂组疫苗诱导的抗猪囊尾蚴病的抗体含量 (IgG或IgG2a)和效价 ,用MTT淋巴细胞转化试验法测定刺激指数 ,进一步证实了CpG基序的种类、数量和空间结构以及与其他佐剂联合对疫苗免疫反应的影响 ,CpG基序以 1个TpC的 5′端开始 ,紧接着 3个GTCGTT基序 ,基序与基序之间由TpT或T分隔 ,在兔、小鼠和猪都能诱导机体产生强烈的免疫反应特别是细胞免疫反应。

Oligodeoxynucleotides (ODN) containing unmethylated CpG dinucleotides within specific sequence contexts (CpG motifs), was synthesized as a danger signal to the vertebrate immune system. And CpG ODN with a nuclease-resistant phosphorothioate backbone, had been shown to be potent Th1-(directed) responses in many papers reported. In order to further testify the roles in veterinary medicine, the immune activating effects of a panel of CpG ODN were tested in vitro and in vivo and the adjuvant activity was identified in rabbits, mice and pigs. The effects of the sequence, number, and spacing of the individual CpG motifs on the immunostimulatory activity of a CpG phosphorothioate ODN were confirmed by MTT method, and the antibodies (IgG or IgG2a) and their titerimmunized with the vaccine plus CpG ODN adjuvant against cysticercus cellulosae were detected by ELISA. An ODN with a TpC dinucleotide at the 5′ end followed by three CpG motifs (5′-GTCGTT-3′) separated by TpT dinucleotides consistently showed the highest activity. Animals vaccinated with the cysticercosis cellulosae vaccine plus the CpG ODN adjuvant developed higher IgG or IgG2a titers than those receiving the vaccine alone or the vaccine with other adjuvants. All these results led the authors to conclude that the optimal CpG motifs for phosphorothioate ODN that is the candidate vaccine adjuvant.