Laboratorio de Inmunología Experimental, Subdirección de Medicina Experimental, Instituto Nacional de Pediatría Secretaría de Salud, Mexico, Distrito Federal, Mexico.
Parasitol Res. 2013 Aug;112(8):3029-33. doi: 10.1007/s00436-013-3476-2. Epub 2013 Jun 10.
Toxoplasma gondii disseminates and causes congenital infection by invasion of the endothelial cells. The aim of this study was to analyze the ability of two strains to invade two endothelial cell types. Tachyzoites of the RH and ME49 strains were expanded in Balb/c and C57BL6-RAG2-/- mice, respectively. Tachyzoites were harvested from 72 h Vero cell cultures and incubated for 30 min to 4 h at 10:1 parasite/cell ratio in 24-well plates, containing monolayers of either HMEC-1 line or human umbilical cells (HUVECs). The number of infected cells and parasitic vacuoles per infected cell were counted in Wright stained slides. A slow increase in the proportion of infected cells occurred but varied according to cell type-parasite strain combination: ME49 tachyzoites invaded up to 63% HMEC-1 cells, while RH parasites infected up to 19% HUVECs. ME49 and RH tachyzoites invaded 49 and 46% HUVECs and HMEC-1 cells, respectively. Reinvasion and formation of new parasitophorous vacuoles of infected cells was more frequent than invasion of noninfected cells. The results support that the factors influencing invasion, and thus dissemination and vertical transmission, are parasite type, host cell type/subtype, and activation state. Interestingly, T. gondii virulence does not seem to relay on its invasion efficiency, but probably on replication speed.
刚地弓形虫通过侵袭血管内皮细胞进行传播并引起先天性感染。本研究旨在分析两种虫株侵袭两种内皮细胞的能力。RH 和 ME49 株速殖子分别在 Balb/c 和 C57BL6-RAG2-/- 小鼠中扩增。从 72 小时 Vero 细胞培养物中收获速殖子，在含有单层 HMEC-1 系或人脐静脉细胞（HUVEC）的 24 孔板中，在 10:1 的寄生虫/细胞比下，10:1 的寄生虫/细胞比下孵育 30 分钟至 4 小时。在 Wright 染色载玻片上计数感染细胞的数量和每个感染细胞的寄生空泡数。感染细胞的比例缓慢增加，但根据细胞类型-寄生虫株组合而有所不同：ME49 速殖子侵袭高达 63%的 HMEC-1 细胞，而 RH 寄生虫感染高达 19%的 HUVECs。ME49 和 RH 速殖子分别侵袭 49%和 46%的 HUVEC 和 HMEC-1 细胞。感染细胞的再侵袭和新形成的寄生空泡比感染非感染细胞更为频繁。这些结果支持这样的观点，即影响侵袭以及传播和垂直传播的因素是寄生虫类型、宿主细胞类型/亚型和激活状态。有趣的是，刚地弓形虫的毒力似乎不在于其侵袭效率，而可能在于其复制速度。
