Escobar-Laines Sergio, Monteon Victor, Ramírez-Sarmiento Carlos, Macedo-Reyes Verónica, Pérez Floribeth León
Fiscalia General del Estado, Campeche, Mexico.
Universidad Autónoma Campeche, Centro de Investigaciones Biomédicas, Campeche, Mexico.
Rev Inst Med Trop Sao Paulo. 2025 Feb 3;67:e5. doi: 10.1590/S1678-9946202567005. eCollection 2025.
Trypanosoma cruzi infection involves transmission of metacyclic trypomastigotes through injured skin or mucosa via contaminated feces from insect vectors like Triatoma dimidiata (Latreille, 1811). Currently, there is insufficient information describing the immune response to feces naturally contaminated with metacyclic trypomastigotes. Mice subcutaneously inoculated with tissue-culture derived trypomastigotes (TCT) or T. dimidiata feces containing metacyclic trypomastigotes (MT) or previously multi-exposed (ME) with feces without metacyclic trypomastigotes and then infected with feces containing metacyclic parasites or only T. dimidiata feces (F) was studied from 15 min to three months post-infection. PCR detection of parasite DNA at the inoculation site demonstrated persistence of T. cruzi DNA up to 20 days in MT and TCT but disappeared earlier in the ME test group. A rapid spread of T. cruzi DNA to regional lymph nodes was observed in all experimental groups. A lower amount of amastigote nests in the heart with concomitant intense inflammation was noticed in ME mice in comparison to the MT group. CD4 + T cell subtypes at popliteal lymph nodes shows early Th1 and Th17 responses at seven days in ME mice, whereas Th1, Th17 and Treg predominate in MT mice after three weeks, and feces induces Th1, Th17 and Treg at a later stage. Our study shows that previous exposure to feces prior to infection with T. cruzi helps control parasitism at the inoculation site and in heart tissue, and an early induction of Th1 and Th17 T cell subtypes.
克氏锥虫感染涉及通过受损皮肤或黏膜传播循环后期锥鞭毛体，其传播途径是经由诸如二点锥猎蝽（拉特雷耶，1811年）等昆虫媒介的污染粪便。目前，关于针对被循环后期锥鞭毛体自然污染的粪便的免疫反应的描述信息不足。对皮下接种组织培养衍生的锥鞭毛体（TCT）或含有循环后期锥鞭毛体（MT）的二点锥猎蝽粪便的小鼠，或先前多次暴露于不含循环后期锥鞭毛体的粪便（ME）然后感染含有循环后期寄生虫的粪便或仅感染二点锥猎蝽粪便（F）的小鼠，在感染后15分钟至三个月进行了研究。接种部位寄生虫DNA的PCR检测表明，克氏锥虫DNA在MT和TCT组中可持续存在20天，但在ME试验组中消失得更早。在所有实验组中均观察到克氏锥虫DNA迅速扩散至区域淋巴结。与MT组相比，ME小鼠心脏中的无鞭毛体巢数量较少，同时伴有强烈炎症。腘淋巴结处的CD4 + T细胞亚型显示，ME小鼠在第7天出现早期Th1和Th17反应，而MT小鼠在三周后Th1、Th17和Treg占主导，粪便在后期诱导Th1、Th17和Treg。我们的研究表明，在感染克氏锥虫之前预先接触粪便有助于控制接种部位和心脏组织中的寄生虫感染，并早期诱导Th1和Th17 T细胞亚型。
