Abstract:

Objective To study protective immunity effects of co-immunization with P30 DNA vaccine and protein vaccine. Methods Forty-eight 5-6 weeks old BALB/c female mice were divid ed into four groups (A,B,C,D), 12 mice of each group. In group A (control group) each mouse was immunized with 100pg pcDNA3.1 plasmid DNA by intramuscular (i. m. ) for three times at week 0,2 and 4; in group B (P30 protein group) each mouse was immunized (i. m. ) with 50 μg rP30+50 μg CFA for three times at week 0, 2 and 4; in group C (pcDNA3. 1-P30 group) each mouse was immunized with 100 μg pcDNA3. 1-P30 plasmid DNA (i. m. ) for three times at week 0, . 2 and 4; in group D (P30 DNA+rP30 co-immunization group) each mouse was immunized with 100 μg pcDNA3. 1-P30 plasmid DNA (i. m. ) for two times at week 0, 2 and immunized by subcutaneous with 50 μg rP30+50 μg CFA at week 4. Each mouse was infected with 100 tachyzoites of Toxoplas ma gondii RH strain four weeks later after last immunization. The antl-P30 antibodies were detect ed with ELISA before the challenge. Results The P30 DNA vaccine was successfully constructed. High titers of antl-P30 antibodies were induced in each mouse immunized with DNA vaccine. The protective trial proved that there was no significant difference between control group and experimen tal group though the survival time of mouse from experimental group had been prolonged. Conclu sion The P30 DNA vaccine could induced high titers of anti- P30 antibodies in immunized mice, and it may be a potential DNA vaccine candidate.

Key words: Toxoplasma gonclii RH strain, P30, DNA vaccine, Protective immunity

摘要：

目的 研究刚地弓形虫RH株主要表面抗原1(P30)DNA疫苗诱导BALB/c小鼠的保护性免疫作用。方法 根据弓形虫P30基因的DNA序列设计一对引物，，将PCR扩增到的P30基因克隆到真核表达载体pcDNA.3.1中。大量制备pcDNA3. 1-P30和pcDNA3.1质粒DNA。将48只 BALB/c小鼠随机分成4组，每组1 2只，空质粒对照组(A组)第O、2、4周经小鼠股四头肌注射100 μg pcDNA3.1质粒DNA;重组P30抗原免疫组(B组)第0、2、4周每鼠经背部皮下多点注射50 μg rP30+福氏完全佐剂；P30 DNA疫苗免疫组(C组)第O、2、4周经小鼠股四头肌注射100 μg pcD- NA3. 1-P30质粒DNA;P30 DNA疫苗和重组P30抗原联合免疫组(D组)第O、2周经小鼠股四头肌洼射100 μg pcDNA3. 1-P30质粒DNA，第4周每鼠经背部皮下多点注射50 μg rP30+福氏完全佐剂。末次免疫4周后每鼠用100个弓形虫速殖子经腹腔感染，观察小鼠存活时间。结果 成功构建刚地弓形虫RH株P30DNA疫苗，动物保护性实验表明，虽然与对照组相比实验组小鼠的存活时间有一定的延长，但差异无显著性。结论 pcDNA3.1-P30 DNA疫苗具有弓形虫病候选DNA疫苗分子的潜力。

关键词: 刚地弓形虫RH株；P30；DNA疫苗；保护性免疫