Breed D G, Dorrestein J, Schetters T P, Waart L V, Rijke E, Vermeulen A N
Department of Parasitology, Intervet International BV, Boxmeer, The Netherlands.
Parasite Immunol. 1997 Mar;19(3):127-35. doi: 10.1046/j.1365-3024.1997.d01-191.x.
Protective immunity to infection by Eimeria parasites has been demonstrated to be dependent on T-cell mediated immune responses and may be associated with the release of cytokines. We have previously shown that the proportion of CD8-expressing T-cells in the peripheral blood of chicken increases transiently at 8 days after a primary infection with Eimeria tenella oocysts. The increase in the CD8+ population coincided with an increased proliferative lymphocyte response upon stimulation with E. tenella sporozoite antigen in vitro. In this study, we further investigated the functional activity of these peripheral blood leucocytes (PBL) by determining both the potential to proliferative and to produce IFN upon stimulation with E. tenella sporozoite antigens and mitogens. Enhanced proliferative responses to parasite antigen were accompanied by reduced responses to T-cell mitogens around 1 week of infection. The IFN activity in the supernatants of the stimulated PBL was measured by the ability to inhibit Semliki Forest Virus (SFV) replication in chicken embryo fibroblasts (CEF) and to activate macrophages, as measured by nitric oxide production. At eight days after infection the highest levels of virus inhibition and NO-production were detected upon stimulation with both E. tenella sporozoite antigen and mitogen. A strong correlation between the individual data of the two methods was found at this timepoint indicating that the produced cytokine was indeed IFN-gamma. These results suggest that around eight days after a primary E. tenella infection a parasite specific T-cell subset with the capacity of produce IFN(-gamma) is circulating which would be involved in the induction of protective immunity against Eimeria tenella.
已证明对艾美耳球虫寄生虫感染的保护性免疫依赖于T细胞介导的免疫反应，并且可能与细胞因子的释放有关。我们之前已经表明，在用柔嫩艾美耳球虫卵囊进行初次感染后8天，鸡外周血中表达CD8的T细胞比例会短暂增加。CD8+细胞群的增加与体外用人芽囊原虫子孢子抗原刺激后淋巴细胞增殖反应的增加相一致。在本研究中，我们通过测定用人芽囊原虫子孢子抗原和丝裂原刺激后外周血白细胞（PBL）的增殖潜力和产生干扰素的能力，进一步研究了这些外周血白细胞的功能活性。对寄生虫抗原的增殖反应增强伴随着感染后1周左右对T细胞丝裂原的反应降低。通过抑制鸡胚成纤维细胞（CEF）中Semliki森林病毒（SFV）复制的能力以及通过一氧化氮产生来测定巨噬细胞活化，来测量刺激后的PBL上清液中的干扰素活性。感染后8天，在用柔嫩艾美耳球虫的子孢子抗原和丝裂原刺激后，检测到最高水平的病毒抑制和一氧化氮产生。此时发现两种方法的个体数据之间存在很强的相关性，表明产生的细胞因子确实是干扰素-γ。这些结果表明，在初次感染柔嫩艾美耳球虫后约8天，一个具有产生干扰素（-γ）能力的寄生虫特异性T细胞亚群正在循环，这可能参与诱导针对柔嫩艾美耳球虫的保护性免疫。
