弓形虫排泄-分泌抗原和可溶性速殖子抗原免疫原性的观察

目的观察弓形虫速殖子排泄-分泌抗原（excreted/secreted antigen,ESA）和可溶性速殖子抗原（soluble tachyzoite antigen,STAg）鼻内免疫小鼠的免疫原性。方法BALB/c小鼠随机分为4组,分别用PBS 20μl/只、体外排泄-分泌抗原（excreted/secreted antigenin vitro,ESAv）、腹腔排泄-分泌抗原（excreted/secreted antigen in mice,ESAm）和STAg各20μg/只鼻内免疫2次,间隔14 d。分别于末次免疫后14 d和44 d每组处死8只小鼠,计数肠上皮内淋巴细胞（intestinal intraepithelial lymphocytes,iIEL）和脾淋巴细胞,ELISA法检测血清IgG和小肠冲洗液sIgA抗体水平。结果实验期间,ESAm组小鼠于二次免疫后状态欠佳,其他各组小鼠健康状况良好。末次免疫后14 d,各抗原组脾淋巴细胞及iIEL均增殖活跃,细胞数与PBS组比较,差异具统计学意义（P〈0.05或P〈0.01）;至免疫后44 d,两种ESA组脾淋巴细胞及iIEL数与PBS组比较差异具统计学意义（P〈0.05）。各抗原组血清IgG水平在免疫后14 d和44 d均明显增高,与PBS组比较差异有统计学意义（P〈0.05或P〈0.01）。免疫后14 d肠液sIgA水平ESAv、ES-Am和STAg组与PBS组比较差异有统计学意义（P〈0.05或P〈0.01）,ESAm和STAg组与ESAv组比较差异有统计学意义（P〈0.05或P〈0.01）,两种ESA组在免疫后44 d与PBS组比较差异仍具统计学意义（P〈0.05）。结论ESAv、ESAm和STAg鼻内免疫均可诱导粘膜及系统的细胞和体液免疫应答,有较强的免疫原性。但ESAm可能对机体有毒副作用,不适宜直接鼻内免疫。

Immunogenicity of Toxoplasma gondii excreted/secreted antigen and soluble tachyzoite antigen

Objective To study the immunogenicity after intranasal immunization with excreted/secreted antigens （ESA） and soluble tachyzoite antigen （STAg） of Toxoplasma. Methods BALB/c mice were randomly divided into four groups. Mice were intranasally immunized with 20 μl PBS per mouse or 20 μg ESA in vitro （ESAv）, ESA from peri toneal fluids（ESAm）or STAg per mouse, respectively, twice at an internal of 2 weeks. 8 mice of each group were killed on day 14 and 44 after the last immunization, respectively. Spleen lymphocytes and intestinal intraepithelial lymphocytes （iIEL） were counted. Serum IgG and slgA in intestinal washes were detected by ELISA. Results In ESAm group, the condition of mice was not good after the last immunization, while mice in other groups were healthy. On day 14 after the last immunization, cell proliferation of spleen lymphocytes and ilEL were observed in all antigen groups, and compared with the PBS group, there was a significant difference （P〈0.05, P〈0.01）. On day 44 after immunization, spleen lym phocytes and iIEL in two ESA groups were still higher than that of PBS group （P〈0.05）. The level of serum IgG in all antigen groups was higher than that of PBS group on both day 14 and day 44 after immunization and had a significant difference （P〈0. 01, P〈0. 05）. On day 14 after immunization, the level of sIgA in ESAv group, ESAm group and STAg group was higher than that of PBS group （P〈0.05, P〈0.01）, and the level in ESAm group and STAg group was higher than that of ESAv group （P〈0. 01, P〈0. 05）. On day 44 after immunization, the level of slgA in two ESA groups was still higher than that of PBS group （P〈0.05）. Conclusion Intranasal immunized with ESAv, ESAm or STAg can effectively induce the mucosal and systemic immune responses. ESAm had toxic side effect for mice, ESAv and STAg may be attractive candidate for Toxoplasma gondii vaccine.