弓形虫ROP5基因与基因佐剂IL-12对小鼠免疫保护性

目的 观察弓形虫ROP5基因疫苗和基因免疫佐剂IL-12共免疫对昆明小鼠所诱导的免疫保护性。方法 大量制备重组质粒pcROP5和pcmIL-12,以100 μg的剂量同时免疫昆明小鼠,PBS组和pcDNA3.1空质粒组作为对照。用ELISA法测定免疫鼠血清中特异性抗体IgG、IgG亚型的表达水平及细胞因子IFN-γ、IL-4的含量,MTT法测定淋巴细胞转化率,观察小鼠受攻击感染弓形虫后的存活时间。结果 质粒pcROP5和pcmIL-12共免疫小鼠3次后,与pcROP5质粒单独免疫组和对照组相比,IL-12基因佐剂的共免疫提高了免疫鼠血清中特异性抗体IgG及IgG亚型IgG2a的表达水平,提高了细胞因子IFN-γ的含量,增加了淋巴细胞的转化率,但IgG1和IL-4的表达水平变化不大;攻击感染后,质粒pcROP5和pcmIL-12共免疫组小鼠存活时间显著延长。结论 弓形虫ROP5基因与基因佐剂pcmIL-12共免疫能增强对小鼠的免疫保护性。

Protective efficacy induced by DNA vaccine encoding ROP5 co-immunized with IL-12 genetic adjuvant against Toxoplasma gondii infection

The purpose of this study was to examine the immunoprotection effect induced by ROP5 DNA vaccine with co-immunization of a plasmid encoding IL-12 (pcmIL-12) as an adjuvant in Kunming mice against Toxoplasma gondii. Mice were co-injected ROP5 with IL-12 at the dosage of 100 μg, controls mice were inoculated with PBS and the empty plasmid pcDNA3.1 respectively. Levels of IgG antibody, IgG isotype, gamma-interferon (IFN-γ), and interleukin-4 were detected by ELISA. MTT assay was used to tested splenocyte proliferation. All mice were challenged with tachyzoites of the virulent T. gondii RH strain after the last immunization to observe the survival time. In this study we detected the higher level of IgG antibody and cytokine IFN-γ in mice after three immunizations by pcROP5 co-immunized with pcmIL-12 compared to pcROP5 group and control groups. In respect to the IgG isotypes, co-immunization with pcmIL-2 enhanced the level of IgG2a, while IgG1 and IL-4 level was not appreciably different. After a lethal challenge of T. gondii RH strain, survival time of the mice co-immunized with pcmIL-12 was prolonged compared to the control groups. Immune responses could be enhanced by ROP5 co-immunized with IL-12 genetic adjuvant.