空肠弯曲菌galE变异株免疫原性及免疫保护性评价

目的评价galE变异株免疫原性及免疫保护效力。方法分别采用galE变异株低菌量及高菌量单次或重复免疫(口服)BALB/c小鼠,ELISA方法检测动物肠液及血清中特异性sIgA及IgG的滴度。免疫后26d,用大剂量CJ攻击被免疫动物,观察galE变异株的保护效应。结果①低菌量及高菌量galE变异株单次或重复免疫后,动物肠液及血液中sIgA及IgG滴度均明显增高,与阴性对照组比较差异非常显著(P<0.01);未显示低剂量与高剂量之间、单次免疫与重复免疫之间抗体水平有明显差异(P>0.05);与亲代株免疫组比较,抗体水平也无明显不同(P>0.05)。②galE变异株免疫可明显降低动物受CJ攻击后的疾病指数(P<0.01),变异株的临床保护效率为79.5%～83.1%;清除CJ肠定植的能力明显高于阴性对照组(P<0.05);低菌量与高菌量之间,单次及重复免疫清除肠道感染效力无明显差异(P>0.05)。结论①galE变异株保留与亲代株相似的免疫原性及免疫保护性,可刺激动物产生特异性抗体,有效保护细菌攻击,明显降低动物疾病指数,缩短细菌肠道定植时间。②galE变异株仅小剂量单次口服即可产生良好的免疫效果。

Immunogenicity and protective efficacy of galE mutant vaccine in mice

To evaluate the immunogenicity of galE mutant vaccine and immune protective efficacy against challenge with high-dose Campylobacter jejuni.BALB/c mice were immunized orally either with single dose of galE mutants in low and high dose or with two doses of galE mutants in low and high dose, respectively, and parental strains were orally administered to immunize mice serving as the positive control. ELISA was performed to examine the titers of CJ-specific secretory IgA and of CJ-specific IgG, in intestinal lavage at 7 days and in sera at 21 days post-immunization, respectively. At 26 days after immunization, the animals were challenged orally by CJ,in high dose (10~9CFU/ per mouse). The protective efficacies of galE mutant vaccine in mice, including protection against disease symptoms (by measuring the degrees of reducing illness indexes), against intestinal colonization (by culturing stool samples) were evaluated. The results showed that ① Significant enhanced titers of CJ-specific sIgA and IgG were detected in intestinal lavage at 7 days and in sera at 21 days, respectively, from the mice immunized by galE mutants whether with single dose in low dose and high dose or with two doses in low dose and high dose. No obvious differences were seen between with single dose and with two dose, as well as between with low dose and with high dose(P>0.05). The difference in levels of the special antibodies was very significant between the mice immunized with galE mutants and the mice immunized with broth (negative control) (P<0.01). No marked difference in inducing levels of sIgA and IgG by parental strains or by galE mutants(P>0.05).② Animals immunized with galE mutants had significant low illness indexes after challenge by high-dose CJ(P<0.01), and the protective efficacies of galE mutants against disease symptoms were 79.5%～83.1%. Animals immunized with galE mutants also showed marked reduction in intestinal colonization, and at 7 days after challenge, 80%-90% of the animals had been colonization negative. The differences in protective efficacies against disease symptoms and against intestinal colonization between galE mutants and parental strains, as well as between different doses of galE mutants, were not significant(P>0.05).It is concluded that ① galE mutants remain similar immunogenicity and the immune protective efficacy to the parental strains, and could effectively induce CJ-specific sIgA and IgG antibodies responses in mice and galE mutants provide protective efficacy against high-dose CJ challenge for vaccinated mice that showed significant low illness indexes, marked reduction in colonization. ②By administered orally, with a single dose only in low dose, the galE mutants could provide a effective protective efficacy for vaccinated mice.