白细胞介素12在伯氏疟原虫红细胞内期感染中的免疫调节作用

Immunoregulatory Effect of Interleukin-12 in the Erythrocytic Stage of P.beighei Infection

[目的 ]探讨白细胞介素 12 (IL 12 )在伯氏疟原虫 (P berghei)红细胞内期感染中的免疫调节作用。[方法 ]BALB/c小鼠接种 5× 10 5个感染P berghei的RBC ,分别以不同剂量 ( 0 0 1、0 0 3、0 10和 0 15 μg/d)IL 12 ,或分别在不同给药时间 (感染前 1d、感染同时、感染后第 3d)给予 0 0 3 μg/dIL 12 ,各组均连续用药 6d。观察各组小鼠原虫血症变化及存活时间。[结果 ]与对照组比较 ,较低剂量 ( 0 0 1或 0 0 3 μg/d)IL 12均可显著推迟血中原虫的出现及原虫血症达峰值的时间 ,但仅 0 0 3 μg/d剂量可明显提高生存率 ;较惯剂量 ( 0 1或 0 15 μg/d)IL 12则增加原虫密度 ,加速小鼠死亡。在感染的第 3d给予 0 0 3 μg/dIL 12 ,对原虫血症、生存率均无明显影响。IL 12不能改变感染的结局 ,最终各组小鼠均死亡。[结论 ]IL 12具有免疫保护和毒副反应双重活性。诱导保护作用而减少毒副作用 ,剂量及给药时间是关键 ,适时地给予适当剂量的IL 12可诱导抗红内期疟原虫的部分保护作用。

[Objective] To study the immunoregulatory effect of interleukin-12 (IL-12) in the erythrocytic stage of P.berghei infection. [Methods] BALB/c mice were infected with 5×10 5 parasitized RBC. The mice were given different doses (0.01,0.03,0.10 and 0.15μg/d) of IL-12 and received 0.03 μg/d in different time (1 day ago, 0 and 3rd day) for 6 days. Parasitemia was monitored and survival time calculated for each group of mice. [Results] Low dose (0.01 and 0.03 μg/d) of IL-12 significantly delayed the emergence and peak of parasitemia, but only 0.03 μg/d resulted in increased survival rate significantly. High dose (0.1 and 0.15 μg/d) led to the progression of parasitemia and caused earlier death. However, any dose of IL-12 did not alter the outcome of infection and all mice eventually died. [Conclusion] The different dose of IL-12 has two kinds of activity (immune protection and toxicity). Appropriate dose and time of IL-12 may be useful in the induction of protective immunity to erythrocytic stage of malaria.