霍乱毒素佐剂联合弓形虫ESA鼻内免疫小鼠抗弓形虫感染作用

Intranasal Immunization with CT Adjuvant and ESA Protects Mice against Toxoplasma gondii Infection

目的 观察霍乱毒素(cholera toxin,CT)佐剂和弓形虫排泄-分泌抗原(ESA)鼻内免疫小鼠诱导的抗弓形虫感染作用。方法 6周龄BALB/c小鼠60只,随机分为3组,每组20只。分别用PBS 20μl、ESA 20μg或CT 1.0μg+ESA 20μg每只滴鼻免疫2次,间隔2周。末次免疫后14 d,用4×104个弓形虫速殖子每只灌胃攻击所有小鼠,观察小鼠健康及死亡情况。速殖子攻击后30 d,计数肝、脑组织内弓形虫速殖子。结果 CT作为佐剂联合弓形虫ESA滴鼻免疫小鼠的健康状况明显好于PBS组和ESA组,存活率(95%)也显著高于PBS组(55%)。与PBS组相比,CT+ESA组肝和脑组织内速殖子数分别减少了80.19%(P<0.001)和78.24%(P<0.005)。CT作为佐剂联合ESA滴鼻免疫小鼠诱导了高水平的黏膜免疫应答和系统免疫应答。结论 CT作为佐剂联合弓形虫ESA滴鼻免疫小鼠诱导的免疫应答可有效抵抗弓形虫速殖子攻击。

Objective To study the effects of intranasal immunization with ESA and CT adjuvant on the protection of mice against Toxoplasma gondii infection and to determine the optimal procedure for intranasal immunization.Methods BALB / c mice were divided into 3 groups,and mice were intranasally immunized with 20 μl PBS,20 μg ESA,or 1.0 μg CT ＋20 μg ESA per mouse,twice at 2 weeks internal,respectively.All mice were challenged intragastrically with 4×104 tachyzoites per mouse on day-14 after the last immunization.The percentage of survival of mice was determined after challenge.Tachyzoites in the livers and brains were counted on the 30th day after challenge.Results The health status of mice in CT adjuvant and ESA group was better than the PBS group,survival rate（95%） was higher than the PBS group（55%）.Compared with the PBS group,tachyzoites in liver（80.19%,P0.001） and brain tissues of CT＋ESA group（78.24%,P0.005） were decreased.Mice receiving intranasal immunization（twice） with CT adjuvant and ESA had a high level of mucosal and systemic immune responses.Conclusion Intranasal immunization with CT adjuvant and ESA can induce protective immunity against Toxoplasma gondii challenged.