摘要
目的研究经口感染弓形虫速殖子小鼠血清及肠道分泌物中IgA含量的变化,探讨肠道粘膜免疫应答机制.方法将6～8周龄BALB/c小鼠100只随机分为对照组和感染组.感染组灌胃接种RH株弓形虫速殖子5×104个/只,对照组给予等量PBS.于感染后第2、4、6、8、10、13、16、19、22、25天,每组各5只小鼠分别处死,摘眼球采血分离血清,收集肠道冲洗液,用ELISA法测定血清及肠液IgA含量.结果对照组血清IgA抗体于第4～8天缓慢升高后保持平稳;感染组小鼠血清IgA水平从第8天起迅速升高,第10天达到高峰,之后迅速下降并接近对照组的水平,第25天再度升高.与对照组相比,感染组血清IgA水平在第10、25天显著升高(P＜0.01).肠液IgA含量明显高于血清,两组小鼠肠道冲洗液中的IgA抗体于第4、6天逐渐升高之后,对照组保持平稳,而感染组于第8天骤然下降并低于升高前的水平,之后又迅速升高,于第13天达到峰值,随后下降并接近对照组水平;第8和13天感染组IgA抗体含量显著低于和高于(P＜0.01)对照组.结论BALB/c小鼠经口感染弓形虫,可有效诱导肠道粘膜的免疫应答,产生高水平的IgA抗体,发挥局部抗虫作用;提示IgA抗体产生变化规律与虫株毒力及小鼠免疫反应特性等因素有关.
Objective This study was performed to determine the mucosal immune response following Toxoplasma
gondii oral infection and observe the responses of IgA antibodies in sera and intestinal secretions in BALB/c mice.
Methods Six- to 8-week-old BALB/c mice were divided into control group and infected group. The ascites containing
tachyzoites of RH strain of infected mice were collected and adjusted to 5×10~4 tachyzoites per 0.5ml. The infected group was
orally feeded with 5×10~4 tachyzoites, while the control group was given PBS solution instead. Five mice in each group were
killed per time-point at day 2, 4, 6, 8, 10, 13, 16, 19, 22, and 25 after infection. The sera and intestinal secretions were
obtained and the anti-T. gondii IgA antibodies were detected by ELISA. Results The level of IgA antibody in the sera and
intestinal secretions were changed greatly. In the sera, IgA antibody persisted at low level until the 8th day post infection
(pi), then it was gradually increased and reached maximum at day 10pi. It was then declined to the level of the control
group, but had tendency of increase around day 25pi. Compare with the control group, the anti-T. gondii IgA showed a great
increase at day 10 and day 25pi. The IgA antibody level in the intestinal secretions was higher than that in the sera. They
increased with the time after infection and reached the peak at day 13pi with a sudden decline at day 8. The antibody level
in the intestinal secretions between the infected and the control group showed extraordinary difference at day 8 and 13pi.
Conclusion During the period of infection in the BALB/c mice orally administered with toxoplasma, the IgA antibody in
the intestinal secretions was the major effector at the local site as the first protective barrier defending the parasite. The time
course of IgA production and its fluctuation were influenced by the strain virulence and the immunity properties of the mice.
出处
《热带医学杂志》
CAS
2004年第1期19-21,33,共4页
Journal of Tropical Medicine
关键词
弓形虫
小鼠
粘膜免疫
SIgA抗体
Toxoplasma gondii
mouse
mucosal immune response
IgA antibody
