Natural killer cells act as early responders in an experimental infection with Neospora caninum in calves
Natural killer cells act as early responders in an experimental infection with Neospora caninum in calves
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DOI：
10.1016/j.ijpara.2006.11.002
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发表时间：
2007-03-01
影响因子：
4
通讯作者：
Olsen, Ingrid
中科院分区：
文献类型：
--
作者：
Klevar, Siv;Kulberg, Siri;Olsen, Ingrid
细胞内原生动物寄生虫犬新孢子虫是全世界牛流产和先天性疾病的原因。我们之前已经证明，自然杀伤（NK）细胞在体外响应犬新孢子虫速殖子而产生 IFN-γ。本研究旨在研究 NK 细胞和其他细胞免疫反应在小牛实验性犬新孢子虫感染模型中的作用。外周血淋巴细胞的表型分析显示，静脉注射后第 4-6 天，NK 细胞百分比下降。接种后，NK 细胞和 CD8+ T 细胞的百分比均增加，并在第 11-15 天达到峰值。全血流式细胞术检测显示，CD4+ T 细胞是主要的 IFN-γ 产生细胞，但在感染的早期阶段，NK 细胞和 CD8+ T 细胞都有助于产生 IFN-γ。我们还比较了两种不同的犬新孢子虫抗原制剂（超声处理的可溶性抗原和完整的热灭活寄生虫）在各种细胞类型中诱导增殖和 IFN-γ 产生的能力。与超声处理的可溶性抗原相比，热灭活的速殖子诱导的产生 IFN-γ 的 NK 细胞数量增加了 3.7 倍。这表明完整的速殖子中存在一些 NK 细胞刺激抗原，而超声处理的可溶性抗原中不存在这些抗原。热灭活的全速殖子也抑制 76 T 细胞增殖，而来自犬新孢子虫的可溶性抗原则不然。我们相信这是首次证明 NK 细胞是小牛犬新孢子虫感染的早期反应者。 (c) 2006 年澳大利亚寄生虫学协会。由 Elsevier Ltd 出版。保留所有权利。
The intracellular protozoan parasite Neospora caninum is a cause of abortion and congenital disease in cattle worldwide. We have previously shown that natural killer (NK) cells produce IFN-gamma in response to N. caninum tachyzoites in vitro. This study aimed to investigate the role of NK cells and other cellular immune responses in an experimental N. caninum infection model in calves. Phenoyping of peripheral blood lymphocytes showed a drop in the percentage of NK cells at days 4-6 after i.v. inoculation, followed by an increase in the percentage of both NK cells and CD8+ T cells which peaked at days 11-15. A whole blood flow cytometric assay showed that CD4+ T cells were the major IFN-gamma producing cells, but in the early stages of the infection both NK cells and CD8+ T cells contributed to IFN gamma production. We also compared the ability of two different N. caninum antigen preparations - sonicated soluble antigens and intact heat-inactivated parasites - to induce proliferation and IFN-gamma production in various cell types. Heat-inactivated tachyzoites induced a 3.7 times greater increase in the number of IFN-gamma producing NK cells compared with sonicated soluble antigens. This indicated the presence of some NK cell-stimulating antigens in the intact tachyzoite that were absent from the sonicated soluble antigens. The heat-inactivated whole tachyzoites also inhibited 76 T cell proliferation while the soluble antigens from N. caninum did not. We believe this is the first time NK cells have been demonstrated to be early responders in N. caninum infection in calves. (c) 2006 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.