特异性IgG抗体在同源与异种疟原虫再感染中的作用研究

目的探讨特异性IgG抗体在同源和异种疟原虫再感染过程中的作用。方法DBA/2小鼠经腹腔感染致死型约氏疟原虫(Py17XL)60d后,采用等量Py17XL、Py17XNL、Pynigeriensis或PbANKA分别再次攻击,计数红细胞感染率;采用ELISA方法动态检测脾细胞培养上清中IFN-γ及其血清中特异性IgG抗体水平的变化。结果Py17XNL和Pynigeriensis再感染小鼠出现一过性低水平的原虫血症;再感染后第4d脾细胞培养上清中IFN-γ水平与正常小鼠相比无显著性差异(P>0.05),而血清中特异性IgG抗体水平明显升高(P<0.01),小鼠全部存活。相比,PbANKA再感染小鼠出现高水平的原虫血症,与其初次感染水平相近,再感染后第4d脾细胞培养上清中IFN-γ水平出现明显升高(P<0.01),而血清中特异性的IgG抗体水平却无明显变化,与正常小鼠水平接近,小鼠全部死亡。结论特异性IgG抗体可在宿主抗同源疟原虫再感染中发挥着重要作用,而对异种疟原虫再感染无保护性。

The effect of specific IgG antibody in re-infected with homologous or heterogenic Plasmodium

To investigate the effect of specific IgG antibody in re-infected with homologous or heterogenic Plasmodium.DBA/2 mice were infected by intraperitoneal injection with 1×106 virulent Py17XL parasitized erythrocytes.After 60 days,mice were subsequently re-infected with Py17XL,Py17XNL,Py nigeriensis or PbANKA,and then the ratio of infected RBC was counted;The levels of splenocyte IFN-γ and serous IgG were dynamically detected by ELISA.It was found that DBA/2 mice from re-infected with Py17XNL or Py nigeriensis showed low levels and transient parasitemia,the level of IFN-γ in spleen cell supernatants didn't increased significantly on day 4 pi compared with control group(P>0.05);however,the level of specific IgG in serum obviously elevated(P<0.01),and all mice survived.In contrast,DBA/2 mice from re-infected with PbANKA showed the high level of parasitemia and the same as that of primary infection;the level of IFN-γ in spleen cell supernatants significantly increased on day 4 pi compared with control group(P<0.01);however,the level of specific IgG in serum didn't obviously elevated(P<0.01),and all mice died.These results indicate that as a main effector,specific IgG play a key role against re-infected with homologous Plasmodium,but haven't protection against re-infected with heterogenic Plasmodium.