Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China.
Malar J. 2012 Aug 8;11:268. doi: 10.1186/1475-2875-11-268.
During malaria infection, multiple pro-inflammatory mediators including IFN-γ, TNF and nitric oxide (NO) play a crucial role in the protection against the parasites. Modulation of host immunity is an important strategy to improve the outcome of malaria infection. Allicin is the major biologically active component of garlic and shows anti-microbial activity. Allicin is also active against protozoan parasites including Plasmodium, which is thought to be mediated by inhibiting cysteine proteases. In this study, the immunomodulatory activities of allicin were assessed during acute malaria infection using a rodent malaria model Plasmodium yoelii 17XL.
To determine whether allicin modulates host immune responses against malaria infection, mice were treated with allicin after infection with P. yoelii 17XL. Mortality was checked daily and parasitaemia was determined every other day. Pro-inflammatory mediators and IL-4 were quantified by ELISA, while NO level was determined by the Griess method. The populations of dendritic cells (DCs), macrophages, CD4+ T and regulatory T cells (Treg) were assessed by FACS.
Allicin reduced parasitaemia and prolonged survival of the host in a dose-dependent manner. This effect is at least partially due to improved host immune responses. Results showed that allicin treatment enhanced the production of pro-inflammatory mediators such as IFN-γ, TNF, IL-12p70 and NO. The absolute numbers of CD4+ T cells, DCs and macrophages were significantly higher in allicin-treated mice. In addition, allicin promoted the maturation of CD11c+ DCs, whereas it did not cause major changes in IL-4 and the level of anti-inflammatory cytokine IL-10.
Allicin could partially protect host against P. yoelii 17XL through enhancement of the host innate and adaptive immune responses.
在疟疾感染过程中，多种促炎介质，包括 IFN-γ、TNF 和一氧化氮（NO），在抵御寄生虫方面发挥着至关重要的作用。调节宿主免疫是改善疟疾感染结局的重要策略。大蒜素是大蒜的主要生物活性成分，具有抗微生物活性。大蒜素还对原生动物寄生虫（包括疟原虫）具有活性，这被认为是通过抑制半胱氨酸蛋白酶来介导的。在这项研究中，使用伯氏疟原虫 17XL 啮齿动物疟疾模型评估了大蒜素在急性疟疾感染期间的免疫调节活性。
为了确定大蒜素是否调节宿主对疟疾感染的免疫反应，在感染伯氏疟原虫 17XL 后用大蒜素处理小鼠。每天检查死亡率，每隔一天确定寄生虫血症。通过 ELISA 定量测定促炎介质和 IL-4，通过 Griess 法测定 NO 水平。通过 FACS 评估树突状细胞（DCs）、巨噬细胞、CD4+T 和调节性 T 细胞（Treg）的群体。
大蒜素以剂量依赖的方式降低寄生虫血症并延长宿主的存活时间。这种作用至少部分是由于改善了宿主的免疫反应。结果表明，大蒜素处理增强了促炎介质的产生，如 IFN-γ、TNF、IL-12p70 和 NO。在大蒜素处理的小鼠中，CD4+T 细胞、DCs 和巨噬细胞的绝对数量显著增加。此外，大蒜素促进了 CD11c+DCs 的成熟，而对 IL-4 和抗炎细胞因子 IL-10 的水平没有产生重大影响。
大蒜素可通过增强宿主固有和适应性免疫反应，部分保护宿主免受伯氏疟原虫 17XL 的侵害。
