重组人IL-2联合STAg鼻内免疫BALB/c小鼠诱导的免疫应答

目的观察重组人白细胞介素-2（rhuIL-2）联合弓形虫可溶性速殖子抗原（STAg）滴鼻免疫小鼠诱导的免疫应答,探讨rhuIL-2的佐剂效应及适宜剂量。方法5～6周龄BALB/c小鼠60只,随机分为6组,每组10只。实验组以STAg20μg或分别加rhuIL-2250、500、1000、2000 IU滴鼻免疫,抗原与佐剂溶于20μlPBS中,对照组以PBS滴鼻,免疫2次,间隔2周。末次免疫后30d,颈椎脱臼处死全部小鼠,ELISA法检测血清IgG和粪便sIgA水平;分离脾淋巴细胞、肠上皮内淋巴细胞（iIEL）,并计数。结果与PBS组相比,各佐剂组血清IgG水平都有增高,其中STAg＋500 IU IL-2组IgG水平增高最显著（P〈0.01）;STAg＋500 IU IL-2组和STAg＋1000 IU IL-2组粪便sIgA抗体水平显著高于PBS组和STAg组（P〈0.05）。联合IL-2佐剂免疫小鼠脾淋巴细胞和产生了增殖性应答,其中STAg＋500 IU IL-2组和STAg＋1000 IU IL-2组脾淋巴细胞数显著高于PBS组和STAg组（P〈0.05）;TAg＋500 IU IL-2组iIEL高于PBS组（P〈0.05）。结论rhuIL-2作为佐剂联合STAg鼻内免疫小鼠可有效诱导粘膜免疫、系统的细胞免疫和体液免疫应答;500 IU IL-2为鼻内免疫小鼠的适宜剂量。

Immune responses induced by intranasal immunization with rhuIL-2 in association with Toxoplasma gondii soluble tachyzoite antigen in BALB/c mice

Objective To investigate the immune responses induced by intranasal immunization with different doses of rhuIL-2 in association with soluble tachyzoite antigen （STAg） and the optimal dose of rhuIL-2 for intranasal immunization in BALB/c mice. Methods Sixty 5-to 6-week-old BALB/c mice were randomly divided into six groups. The mice of experimental groups were immunized intranasally two times at 14-day intervals with 20μg STAg alone, 20 μg STAg plus 250 IU IL-2, 20 μg STAg plus 500 IU IL-2, 20 μg STAg plus 1 000 IU IL-2 or 20 μg STAg plus 2 000 IU IL-2. The mice of control group were immunized intranasally with PBS at the same time. All animals were killed on day 30 after the last immunization. The levels of sera IgG and feces sIgA were detected by ELISA, and the splenic lymphocytes and intestinal intraepithelial lymphocytes （iIEL） were counted. Results The levels of sera IgG （P（0.01） and feces sIgA （P〈 0.05） in groups of STAg plus 500 IU IL-2 and STAg plus 1 000 IU were obviously higher than that of PBS group and STAg group （P（0.05）. Proliferative responses were observed in iIEL and splenic lymphoeytes, the splenic lymphocytes in STAg plus 500 IU IL-2 and STAg plus 1 000 IU IL-2 groups were obviously higher than that of PBS group and STAg group （P〈0.05）, iIEL in STAg plus 500 IU group was higher than that of PBS group （P〈0.05）. Conclusion The cellular and humoral immune responses in systemic and mueosal sites are efficiently induced by intranasal immunization with rhuIL-2 in association with Toxoplasma STAg, and the optimal dose of rhuIL-2 as adjuvant for intranasal immunization is 500 IU IL-2 in BALB/c mice.