Laboratório de Biologia Molecular de Parasitas e Fungos, Instituto Adolfo Lutz, Sao Paulo, Brazil.
Nucleo de Microscopia Eletrônica, Instituto Adolfo Lutz, Sao Paulo, Brazil.
Acta Trop. 2021 Jul;219:105915. doi: 10.1016/j.actatropica.2021.105915. Epub 2021 Apr 18.
This study investigated the participation extracellular vesicles (EVs) in Toxoplasma gondii-host interaction. EVs of three T. gondii strains (RH, ME-49 and VEG) were purified by chromatography and ELISA. Results of "nanoparticle tracking analysis" and scanning electron microscopy showed that RH strain released more EVs than other strains. Images of transmission electron microscopy showed that in beginning of incubation (culture medium), EVs were inside of tachyzoites preparing to be released. After 24 hours, they were largely produced inside tachyzoites and were released through plasma membrane. The parasite burden of mice infected with RH strain plus EVs was increased and with early death of 1-2 days compared of those that received only parasites. EV proteins of ME-49 and VEG strains were poorly reactive to sera of infected patients in imunoblot. However, those from RH strain were reactive against sera of patients with cerebral toxoplasmosis. EVs stimulated murine splenocytes caused similar production of IFN-γ and IL-10 levels. RH strain derived EVs stimulated more TNF-α than those stimulated by other strains. T. gondii and infected hosts can express the same miRNAs (miR-155-5p, miR-125b-5p, miR-423-3p). In conclusion, T. gondii derived EVs promote host-parasite interactions, modulate host immune responses, carry virulent factors and cause an imbalance in cellular immune response.
本研究探讨了细胞外囊泡（EVs）在刚地弓形虫-宿主相互作用中的参与。通过色谱法和 ELISA 从三种刚地弓形虫株（RH、ME-49 和 VEG）中纯化 EVs。“纳米颗粒跟踪分析”和扫描电子显微镜的结果表明，RH 株释放的 EVs 比其他株更多。透射电子显微镜的图像显示，在孵育开始时（培养基），EVs 位于准备释放的速殖子内部。24 小时后，它们在速殖子内部大量产生，并通过质膜释放。与仅接受寄生虫的小鼠相比，感染 RH 株加 EVs 的小鼠寄生虫负担增加，并且 1-2 天内早亡。ME-49 和 VEG 株的 EV 蛋白在免疫印迹中对感染患者的血清反应不佳。然而，来自 RH 株的 EV 蛋白对脑弓形虫病患者的血清有反应。EVs 刺激小鼠脾细胞引起相似的 IFN-γ和 IL-10 水平产生。与其他菌株刺激相比，RH 株衍生的 EVs 刺激更多的 TNF-α。弓形虫和感染宿主可以表达相同的 miRNAs（miR-155-5p、miR-125b-5p、miR-423-3p）。总之，弓形虫衍生的 EVs 促进宿主-寄生虫相互作用，调节宿主免疫反应，携带毒力因子并导致细胞免疫反应失衡。
