CpG DNA重组质粒对猪O型口蹄疫病毒抗原的免疫佐剂效应

Adjuvant Effect of CpG DNA Recombinant Plasmid to Antigen of FMDV in vivo

作者应用含CpG基序序列的重组质粒（即CpG DNA）作为免疫佐剂,评价其对猪O型口蹄疫病毒抗原疫苗的免疫增强效果。结果表明：CpG DNA重组质粒与猪口蹄疫灭活病毒抗原疫苗配伍免疫小鼠,CpG DNA重组质粒对小鼠具有较强的免疫佐剂效应,能促进口蹄疫病毒抗原诱导产生较高水平的特异性抗体,其抗体滴度是空载体疫苗对照的2倍。CpG DNA重组质粒与商品化猪口蹄疫灭活疫苗配伍免疫试验猪,其增强抗原诱导的特异性抗体滴度最高可达标准疫苗的4倍以上,也显著高于空载体疫苗对照 与病毒纯化抗原配伍免疫动物,攻毒后其免疫保护效力的PD50高达13.00,远高于标准疫苗对照（PD504.69）。在CpG DNA重组质粒剂量选择试验中,含低剂量的CpG DNA疫苗（50、200μg.头份-1）都比高剂量组（500μg.头份-1）诱导的抗体滴度高,其中50和200μg.头份-1的CpG DNA剂量,在接种后14~32 d诱导的抗体滴度高达1∶1500,是标准疫苗的4~5倍,而500μg.头份-1剂量诱导的抗体仅是标准疫苗的2倍,说明CpG DNA重组质粒在低剂量时即可发挥强烈的佐剂效应。研究表明CpG DNA对猪O型口蹄疫病毒抗原疫苗有较强的免疫佐剂效应,且使用剂量低,应用前景广阔。

The objective of this work was to evaluate the adjuvant effects of recombinant plasmid inserted CpG motif （ CpG DNA ） to antigen of type O FMDV（Foot and mouth disease virus） in vivo. Using CpG DNA as an adjuvant co-administrated with commercial killed vaccine or purified antigen of type O FMDV to mice or pigs, the results showed that CpG DNA posses an augmented immune response with significant levels of the specific antibody to antigen after intramuscular im- munization in mice, antibody titer was 2-fold higher than that of the control vaccine of plasmid vector. In target animal trial, vaccine with CpG DNA co-vaccinated to pigs also induced over 4 folds antibody titer than that of commercial vaccine alone. Purified antigen vaccine of type O FM- DV with CpG DNA, showed potent immunity protective effect, which PD50 value arrives above 13.00, was far higher than that of purified antigen vaccine without CpG DNA （only 4.69）. In dosage experiment of recombinant plasmid, vaccine with low dose （50 μg and 200μg） of CpG DNA initiated significantly increased antibody titer of 1 ： 1 500, which was 4 to 5-fold than that of standard vaccine, while dose of 500μg was only 2-fold. These works proved that the recombi- nant plasmids of CpG DNA can enhance the level of immune responses to antigen of type O FM- DV in swine, and could develop as an ideal adjuvant for practical application.