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目的观察弓形虫速殖子排泄一分泌抗原(excreted/secreted antigen,ESA)和可溶性速殖子抗原(solubletachyzoite antigen,STAg)鼻内免疫小鼠诱导的抗弓形虫感染作用。方法BALB/c小鼠64只随机分为4组,每组16只,分别用磷酸盐缓冲液(PBS)(对照组)20μl/只、体外排泄-分泌抗原(excreted/secreted antigen in vitro,ESAv)20μg/只、腹腔排泄-分泌抗原(excreted/secreted antigen in mice,ESAm)20μg/只和STAg20μg/只滴鼻免疫小鼠2次,间隔14 d。末次免疫后14 d每组处死8只小鼠,ELISA法检测血清IgG和小肠冲洗液sIgA。每组剩余8只小鼠用RH株弓形虫速殖子1×104个/只灌胃攻击,记录小鼠健康情况。攻击后30 d处死小鼠,计数脾、脑组织内弓形虫虫荷(速殖子数)。结果ESAm组小鼠于2次免疫后出现轻微竖毛、倦怠等症状,其他各组小鼠健康状况良好。免疫后14 d,各抗原组血清IgG水平均明显高于对照组(P<0.001);ESAv(P<0.05)、ESAm(P<0.001)和STAg(P<0.001)组肠液sIgA水平明显高于对照组,EsAm(P<0.001)和sTAg(P<0.05)组高于EsAv组。弓形虫攻虫后:30 d,各抗原组小鼠脾、脑组织内虫荷显著低于对照组(P<0.01),ESAv、ESAm和sTAg组脾内速殖子减虫率分别为49.2%,49.52%和51.94%,脑内减虫率分别为46.83%,50.81%和51.18%。结论ESAv、ESAm和STAg鼻内免疫均能产生抗弓形虫感染的部分保护,但ESAm可能对机体有毒副作用,不适宜直接鼻内免疫。
Objective To observe the anti-Toxoplasma infection induced by intranasal immunization of Toxoplasma gondii excreted / secreted antigen (ESA) and soluble tachyzoite antigen (STAg). Methods Sixty-four BALB / c mice were randomly divided into 4 groups with 16 mice in each group. Excreted / secreted antigen in vitro (ESAv ) 20μg / only, excreted / secreted antigen in mice (ESAm) 20μg / only and STAg 20μg / only intranasal immunization of mice 2 times, an interval of 14 days. On the 14th day after the last immunization, 8 mice in each group were sacrificed, and serum IgG and sIgA were measured by ELISA. The remaining 8 mice in each group were challenged with 1 × 10 4 tachyzoites of Toxoplasma gondii RH gavage per mouse, and the health of the mice was recorded. Mice were sacrificed at 30 days after challenge and the doses of Toxoplasma gondii (tachyzoites) in the spleen and brain were counted. Results The mice in ESAm group showed slight vertical hair loss and fatigue after 2 immunizations. The mice in other groups showed good health. Serum IgG levels of each antigen group were significantly higher than those of the control group on day 14 after immunization (P <0.001). The levels of sIgA in ESAv (P <0.001) and STAg (P <0.001) The control group, EsAm (P <0.001) and sTAg (P <0.05) group than the EsAv group. Twenty-four days after Toxoplasma gondii attack, the worm burden in spleen and brain tissue of each antigen group was significantly lower than that of the control group (P <0.01). The rates of tachyzoites in ESAv, ESAm and sTAg groups were 49.2% , 49.52% and 51.94% respectively. The worm reduction rates in the brain were 46.83%, 50.81% and 51.18% respectively. Conclusion ESAv, ESAm and STAg can both produce partial protection against Toxoplasma gondii infection. However, ESAm may have toxic and side effects on the body and is not suitable for direct intranasal immunization.