Cytokine production and phenotype of Histomonas meleagridis-specific T cells in the chicken.
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ABSTRACT: 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-? 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-? protein and IL-13 mRNA by intracellular cytokine staining and PrimeFlow™ RNA Assays, respectively, in CD4+ and CD8?+ 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-?-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-?-producing CD4-CD8?- 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-CD8?- 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 ?? T cells, which will be addressed in future studies.
SUBMITTER: Lagler J
PROVIDER: S-EPMC6896354 | biostudies-literature | 2019 Dec
REPOSITORIES: biostudies-literature
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