da Silva Claudio V, Kawashita Silvia Y, Probst Christian M, Dallagiovanna Bruno, Cruz Mário C, da Silva Erika A, Souto-Padrón Thaís C B S, Krieger Marco A, Goldenberg Samuel, Briones Marcelo R S, Andrews Norma W, Mortara Renato A
Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
Microbes Infect. 2009 Apr;11(5):563-70. doi: 10.1016/j.micinf.2009.03.007. Epub 2009 Apr 1.
Trypanosoma cruzi genomic database was screened for hypothetical proteins that showed high probability of being secreted or membrane anchored and thus, likely involved in host-cell invasion. A sequence that codes for a 21kDa protein that showed high probability of being secreted was selected. After cloning this protein sequence, the results showed that it was a ubiquitous protein and secreted by extracellular amastigotes. The recombinant form (P21-His(6)) adhered to HeLa cells in a dose-dependent manner. Pretreatment of host cells with P21-His(6) inhibited cell invasion by extracellular amastigotes from G and CL strains. On the other hand, when the protein was added to host cells at the same time as amastigotes, an increase in cell invasion was observed. Host-cell pretreatment with P21-His(6) augmented invasion by metacyclic trypomastigotes. Moreover, polyclonal antibody anti-P21 inhibited invasion only by extracellular amastigotes and metacyclic trypomastigotes from G strain. These results suggested that P21 might be involved in T. cruzi cell invasion. We hypothesize that P21 could be secreted in the juxtaposition parasite-host cell and triggers signaling events yet unknown that lead to parasite internalization.
对克氏锥虫基因组数据库进行筛选，寻找那些显示出高分泌或膜锚定可能性、因此可能参与宿主细胞入侵的假设性蛋白质。选择了一个编码21kDa蛋白质的序列，该蛋白质显示出高分泌可能性。克隆该蛋白质序列后，结果表明它是一种普遍存在的蛋白质，由细胞外无鞭毛体分泌。重组形式（P21-His(6)）以剂量依赖方式粘附于HeLa细胞。用P21-His(6)预处理宿主细胞可抑制来自G株和CL株的细胞外无鞭毛体的细胞入侵。另一方面，当该蛋白质与无鞭毛体同时添加到宿主细胞时，观察到细胞入侵增加。用P21-His(6)预处理宿主细胞可增强循环后期锥鞭毛体的入侵。此外，抗P21多克隆抗体仅抑制来自G株的细胞外无鞭毛体和循环后期锥鞭毛体的入侵。这些结果表明P21可能参与克氏锥虫的细胞入侵。我们假设P21可能在寄生虫与宿主细胞并列时分泌，并触发导致寄生虫内化的未知信号事件。
