IL-12在抗伯氏疟原虫感染中的免疫佐剂作用

目的　探讨IL - 12在抗伯氏疟原虫感染中的免疫佐剂作用。方法　BALB/c小鼠分别皮下用抗原sAg、IL - 12、抗原sAg联合IL - 12或抗原sAg联合弗氏佐剂进行免疫 ,共免疫 3次 ,每次间隔 2wk ,末次免疫后 1wk以 5× 10 5个感染P berghei的RBC攻击感染 ,观察各组小鼠原虫血症变化及存活时间。攻击感染后 1wk收集各组小鼠血清 ,采用ELISA检测血清中IFN -γ、IL - 4、IL - 10及IgG水平。结果　抗原sAg联合IL - 12免疫可较其它各免疫组及未免疫对照组显著延长小鼠存活时间 ,且全部小鼠在原虫血症达 5 0 %时开始死亡 ;而单独抗原sAg、单独IL - 12或抗原sAg联合弗氏佐剂免疫与未免疫比较 ,对小鼠原虫血症及存活时间均无明显影响 ,且半数以上小鼠均在原虫血症小于 2 5 %时死亡。抗原联合IL - 12免疫组小鼠血清中IFN -γ及IgG水平较单独抗原sAg、单独IL - 12及未免疫组显著升高。 结论　结果表明 ,IL - 12与sAg抗原共同免疫小鼠可诱导对P berghei攻击感染的部分抵抗力 ,具有一定的免疫佐剂活性。

The immune adjuvant effect of IL-12 on the infections with Plasmodium berghei

To investigate the immune adjuvant effect of IL-12 on the infections with Plasmodium berghei,BALB/c mice were immunized subcutaneously by 3 times at 0,2 and 4 week with soluble crude antigen (sAg),IL-12,sAg plus IL-12 or sAg plus CFA respectively,and challenged one week after the final boosting with 5×105 parasitized RBC.Parasitemia in mice was monitored by blood smears,and the survival time was calculated until death in each group.One week after challenge,sera of mice were collected,and the serum levels of IFN-γ,IL-4,IL-10 and IgG were measured by ELISA.The results showed that immunization of BALB/c mice with sAg plus IL-12 could significantly prolong the survival times of the immunized group in comparison with those of other experimental groups or un-immunized control,and all the mice started to die when the parasitemia had attained 50%.Whereas,immunization with sAg alone,IL-12 alone,or sAg plus CFA had no apparent effect on host parasitemia or survival times of mice in comparison with un-immunized group,and half of mice died before parasitemia had attained to 25%.In addition,mice immunized with sAg plus IL-12 showed maximal increase of serum levels of IFN-γand IgG in comparison with the un-immunized mice or mice immunized with sAg or IL-12 alone.The results suggest that IL-12 may be used as an adjuvant to boost the immune responses.