STAg联合CpG ODN滴鼻免疫小鼠诱导的免疫应答

Immune Response Induced by Intranasal Immunization with Toxoplasma gondii STAg Plus CpG ODN in Mice

目的观察弓形虫可溶性速殖子抗原(STAg)联合CpG寡核苷酸(CpG ODN)滴鼻免疫BALB/c小鼠诱导的免疫应答,探讨CpG ODN的佐剂效应。方法将72只雌性BALB/c小鼠随机分为实验组和对照组,每组36只。实验组以20μgSTAg联合10μg CpG ODN滴鼻免疫,对照组以PBS滴鼻,共免疫2次,间隔2周。于末次免疫后第1、2、3、4、5、6周每组分别随机处死6只小鼠,ELISA法检测血清IgG和小肠冲洗液sIgA,分离脾和肠上皮内淋巴细胞(iIEL)并计数。结果实验组小鼠血清IgG水平在末次免疫后第1周即显著高于对照组,在5周内呈持续上升趋势,至第6周出现下降。实验组小鼠小肠冲洗液sIgA水平在各个时间点均高于对照组,第2～6周差异有统计学意义。实验组小鼠脾淋巴细胞和iIEL数量均明显增生,脾淋巴细胞数量在第3周时达高峰,第2～6周显著高于对照组;iIEL数量分别在第2、4周出现2个峰值,第2、3、4周显著高于对照组。结论STAg与CpG ODN联合滴鼻免疫BALB/c小鼠,可有效诱导黏膜部位和系统的体液免疫和细胞免疫应答,且可持续较长时间。

Objective To observe the immune response induced by intranasal immunization with soluble tachyzoite antigen （STAg） of Toxoplasma gondii plus CpG ODN in mice and explore the effect of CpG ODN as an adjuvant. Methods A total of 72 BALB/c mice were randomly divided into test and control groups, 36 for each. The mice in test group were immunized with 20 μg of STAg plus 10 μg of CpG ODN by intranasal drip for 2 times at an interval of 2 weeks, and those in control group with PBS. Six mice in each group were killed at the 1st, 2nd, 3rd, 4th, 5th and 6th weeks after the last immunization respectively for determination of IgG in sera and sIgA in intestinal washes by ELISA. Meanwhile, the splenic lymphocytes and intestinal lymphocytes （ilELs） were isolated and counted. Results The serum IgG levels of mice in test group at the 1st week after the last immunization were significantly than those in control group, and showed a continuously increasing tendency within 5 weeks, while decreased at the 6th week. The sIgA levels in intestinal washes of mice in test group were higher on various time points, and significantly higher at the 2nd to the 6th weeks after the last immunization than those in control group. Both the numbers of splenic lymphocytes and iIELs of mice in test group in- creased significantly. The number of splenic lymphocytes reached a peak value at the 3rd week after the last immunization and was significantly higher than that of mice in control group at the 2nd to the 6th weeks. However, the number of iIELs reached a peak value for 2 times at the 2nd and the 4th week respectively, and was significantly higher than that of mice in control group at the 2nd, 3rd and 4th weeks. Conclusion The intranasal immunization with STAg plus CpG ODN induced both mucosal and systemic immune r sponse in BALB/c mice.