The protozoan parasite Histomonas meleagridis is the causative agent of the re-emerging disease histomonosis of chickens and turkeys. Due to the parasite's extracellular occurrence, a type-2 differentiation of H. meleagridis-specific T cells has been hypothesized. In contrast, a recent study suggested that IFN-γ mRNA+ cells are involved in protection against histomonosis. However, the phenotype and cytokine production profile of H. meleagridis-specific T cells still awaits elucidation. In this work, clonal cultures of a virulent monoxenic strain of H. meleagridis were used for infecting chickens to detect IFN-γ protein and IL-13 mRNA by intracellular cytokine staining and PrimeFlow™ RNA Assays, respectively, in CD4+ and CD8β+ T cells. Infection was confirmed by characteristic pathological changes in the cecum corresponding with H. meleagridis detection by immunohistochemistry and H. meleagridis-specific antibodies in serum. In splenocytes stimulated either with H. meleagridis antigen or PMA/ionomycin, IFN-γ-producing CD4+ T cells from infected chickens increased in comparison to cells from non-infected birds 2 weeks and 5 weeks post-infection. Additionally, an increase of IFN-γ-producing CD4-CD8β- cells upon H. meleagridis antigen and PMA/ionomycin stimulation was detected. Contrariwise, frequencies of IL-13 mRNA-expressing cells were low even after PMA/ionomycin stimulation and mainly had a CD4-CD8β- phenotype. No clear increase of IL-13+ cells related to H. meleagridis infection could be found. In summary, these data suggest that H. meleagridis infection induces a type-1 differentiation of CD4+ T cells but also of non-CD4+ cells. This phenotype could include γδ T cells, which will be addressed in future studies.

中文翻译：

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鸡中组织性组织细胞特异T细胞的细胞因子产生和表型。

原生动物的寄生虫组织性组织病是导致鸡和火鸡再次出现疾病组织病的病原体。由于该寄生虫在细胞外的出现，已经假设了H. meleagridis特异性T细胞的2型分化。相反，最近的一项研究表明，IFN-γmRNA +细胞参与了针对组织病的保护。但是，尚需阐明阐明H. meleagridis特异性T细胞的表型和细胞因子的产生情况。在这项工作中，强毒的单核嗜血杆菌的克隆培养物被用于感染鸡，以通过细胞内细胞因子染色和PrimeFlow™RNA分析分别在CD4 +和CD8β+ T细胞中检测IFN-γ蛋白和IL-13 mRNA。 。盲肠中与H对应的特征性病理变化证实了感染。通过免疫组织化学检测meleagridis和血清中H. meleagridis特异性抗体。在用麻疯杆菌抗原或PMA /离子霉素刺激的脾细胞中，与感染后2周和5周的未感染鸡相比，感染鸡产生的IFN-γCD4 + T细胞增加。另外，检测到在麻疯杆菌抗原和PMA /离子霉素刺激下产生IFN-γ的CD4-CD8β-细胞增加。相反，即使在PMA /离子霉素刺激后，表达IL-13 mRNA的细胞的频率也较低，并且主要具有CD4-CD8β-表型。没有发现明显的与H. meleagridis感染有关的IL-13 +细胞增加。总之，这些数据表明，H。meleagridis感染诱导了CD4 + T细胞但非CD4 +细胞的1型分化。该表型可能包括γδT细胞，