卵清蛋白特异性免疫耐受的诱导及鉴定

Induction and identification of peripheral tolerance to ovalbumin administered intravenously or orally

【目的】建立对卵清蛋白(OVA)免疫耐受的Babl/c小鼠模型。【方法】分别设立A、B、C、D、E、F试验组及相应对照组。A、B组小鼠口服OVA,隔天1次,共服5次,口服剂量分别为50或100μg/只;C、D、E、F组小鼠经尾静脉注射OVA 1次,剂量分别为5,10,50和100μg/只;分别于口服完成7 d后或尾静脉注射5 d后免疫小鼠,免疫后15 d,MTT法测定小鼠OVA特异性淋巴细胞增殖情况,间接ELISA测定小鼠血清抗OVA的IgG水平。C、D组小鼠分别进行二、三次免疫并检测抗体。【结果】A、B组小鼠淋巴细胞增殖的刺激指数(Simulate index,SI)分别为0.603±0.03和0.715±0.08,增殖效果不佳;C、D组小鼠SI值分别为0.096±0.01和0.083±0.01,淋巴细胞不增殖;E、F组小鼠淋巴细胞增殖效果与正常小鼠无差异。第一次免疫后,各组小鼠OVA抗体效价与相应对照组小鼠的OVA抗体无显著差异;C、D组在二免、三免后抗体水平持续下降,不呈现再次应答规律。【结论】小鼠口服小剂量OVA可以建立不完全细胞免疫耐受,经尾静脉注射小剂量OVA可以建立完全免疫耐受。

[Objective] The study is to establish a model tolerance to ovalbumin. [Mathod] Mice gastrically intubated ovalbumin （OVA） had been divided into experiment group A,B,C,D,E and F and their corresponding control groups. Group A and 13 were at the dose of 50 or 100μg every other day for 5 times. The rest were i. v. at the dose of 5,10,50 or 100 μg once for each. The oral administration groups and the intravenously injected groups were challenged with 200μg OVA,at 7 days or 5 days interval,respectively. 15 days later,mice were sacrificed. Lymphocytes responses were assessed by MTT method and antibody were tested by ELISA. And then group C and D injected 5 or 10μg were exposed to the second and the third immunization. Antibody was detected at 15 days interval for 4 times. [Result] The regimen of OVA oral administration group A and 13 can induce Ag-specific lymphocytes profound suppression, with simulate index 0. 603±0.03 and 0. 715±0.08,repectively. And the anti-OVA IgG level was remarkablly affected. As to the intravenous group C and D,these lymphocytes from mice i. v. 5 or 10 μg OVA were totally unrespon- siveness in all mice tested, with index 0. 096 ± 0.01 and 0. 083 ±0.01, respectively while group E and F were normally responded. Antigen-specific 13 cells were normally responded with the first immunization. 13ut they had no reactivity to repetitious immunization and anti-OVA IgG were gently declined in 2 months. [Conclusion] Low dose of OVA intravenous injection can initiate specific immune tolerance while the oral administration in this experiment can just suppress the responses of T cells and B cells evidently.