Selenium (Se) deficiency inhibits immune cell differentiation, affects immune response, and leads to cellular and humoral immune dysfunction. However, the impact of Se deficiency on the differentiation and Th1/Th2 balance of dendritic cells is still unclear. In this study, we replicated a model of Se-deficient chickens by feeding the chickens with a low-Se diet (i.e., the content of Se is 0.008 mg per kg diet). On this basis, we explored the effect of Se deficiency on the differentiation of chicken dendritic cells by induction culture of peripheral blood monocyte cells. We induced chicken dendritic cells by incubating mononuclear cells with a 100 ng mL-1 recombinant chicken granulocyte-macrophage colony-stimulating factor and 20 ng mL-1 recombinant chicken IL-4 for total 7 days. The results showed that Se deficiency decreased the expression of cell-surface markers including CD11c, CD40, CD86, and MHC II. Furthermore, we analyzed the cytokine profiles using real-time quantitative PCR and ELISA. The results indicated that Se deficiency inhibited the expression of selenoproteins and changed the secretion of IL-10, IL-12p40, and IFN-γ. Additionally, Se deficiency weakened the ability of dendritic cells to stimulate the proliferation of mixed allogeneic lymphocytes. In conclusion, Se deficiency suppressed the differentiation and immune function of chicken dendritic cells by down-regulating the expression of CD11c, CD40, CD86, MHC II, and selenoproteins. The result also showed that the Th1/Th2 imbalance was induced by enhancing the secretion of Th1-type cytokine IL-12p40 and IFN-γ and reducing that of Th2-type cytokine IL-10. Our findings contribute to understanding the mechanism of Se deficiency in the differentiation and immune function of chicken dendritic cells.

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This study aimed to investigate the possible mechanisms of environmental metal pollutant lead (Pb)-induced apoptosis in chicken. Forty 8-day-old healthy chickens were randomly assigned to two groups (n = 20/group) after raising standard commercial diet and drinking water for 1 week: including control group and Pb group ((CHCOO)Pb 350 mg/L of drinking water); the chickens were given euthanasia and collected livers at 90 days. A significant increase of apoptosis rate were found in Pb group and Pb induced obvious ultrastructural changes of chicken liver. The mRNA levels of glycometabolism key enzymes were significantly lower in Pb group than those in controls. Higher levels of malondialdehyde (MDA) and nitric oxide (NO) were observed in Pb group; the activities of antioxidant enzymes and ATPases were significantly lower in Pb group than those in controls, while the inducible nitric oxide synthase (iNOS) activity was on the contrary. The mRNA and protein levels of pro-apoptotic genes were all lower in Pb group than those in controls. Altogether, Pb-induced mitochondrial swelling and nuclear chromatin condensation, oxidative stress, energy metabolism disorder, thereby lead to apoptosis via mitochondrial pathway in chicken liver, suggesting that Pb-induced mitochondrial pathway apoptosis plays an important role in the mechanisms of Pb cytotoxicity to chicken liver.

Toxoplasma gondii is an apicomplexan parasite, which has three unique secretory organelles: micronemes, rhoptries, and dense granules. Almost all the secreted proteins are transported through the endoplasmic reticulum (ER) and Golgi system to function in their respective destination by accurate targeting and packaging. Glutathione S‐transferase (GST) is a supergene family enzyme that has multiple functions, which include regulation of cell proliferation and death signaling pathways, and participation in transportation and metabolism in mammal cells. However, the role of GST in Toxoplasma gondii has not been explained. In this study, we identified three GST proteins in T gondii, of which GST2 acts as a membrane protein that localizes to the Golgi‐endosomal system and colocalizes with proteins involved in vesicle transport as well, including synaptobrevin, putative sortilin (VPS10), Rab5 and Rab6, which function as vesicle transport factors. Moreover, the loss of TgGST2 leads to Rab5 and Rab6 distribution of discrete puncta, and incorrect localization and decreased expression of several secretory proteins, and to significantly reduced invasion capacity and virulence to mice. Consistent with its relation to vesicle transport proteins, the distribution of TgGST2 relies on post‐Golgi trafficking. Overall, our findings demonstrated that TgGST2 contributes to vesicle trafficking and plays a critical role in parasite lytic cycle.