Hamza Eman, Steinbach Falko, Marti Eliane
Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Vet Immunol Immunopathol. 2012 Jul 15;148(1-2):139-44. doi: 10.1016/j.vetimm.2011.05.033. Epub 2011 Jun 6.
Insect bite hypersensitivity (IBH) is an IgE-mediated dermatitis caused by bites of midges from the genus Culicoides. We have shown previously that peripheral blood mononuclear cells (PBMC) from IBH-affected horses produce higher levels of IL-4 and lower levels of IL-10 and TGF-β1 than those from healthy horses, suggesting that IBH is associated with a reduced regulatory immune response. FoxP3 is a crucial marker of regulatory T cells (Tregs). Here we have determined the proportion of CD4(+)CD25(+)FoxP3(+) T cells by flow cytometry in PBMC directly after isolation or after stimulation with Culicoides extract or a control antigen (Tetanus Toxoid). There were no differences between healthy and IBH horses either in the proportion of FoxP3(+)CD4(+)CD25(+) cells in freshly isolated PBMC or in the following stimulation with Tetanus Toxoid. However, upon stimulation of PBMC with the allergen, expression of FoxP3 by CD4(+)CD25(+high) and CD4(+)CD25(+dim) cells was significantly higher in healthy than in IBH horses. Addition of recombinant IL-4 to PBMC from healthy horses stimulated with the allergen significantly decreased the proportion of FoxP3 expressing cells within CD4(+)CD25(+high). These results suggest that IBH is associated with a decreased number of allergen-induced Tregs. This could be a consequence of the increased IL-4 production by PBMC of IBH-affected horses.
昆虫叮咬超敏反应（IBH）是一种由库蠓属蠓虫叮咬引起的IgE介导的皮炎。我们之前已经表明，与健康马匹相比，受IBH影响的马匹外周血单个核细胞（PBMC）产生更高水平的IL-4以及更低水平的IL-10和TGF-β1，这表明IBH与调节性免疫反应降低有关。FoxP3是调节性T细胞（Tregs）的关键标志物。在此，我们通过流式细胞术测定了分离后或用库蠓提取物或对照抗原（破伤风类毒素）刺激后的PBMC中CD4(+)CD25(+)FoxP3(+) T细胞的比例。在新鲜分离的PBMC中FoxP3(+)CD4(+)CD25(+)细胞的比例，以及随后用破伤风类毒素刺激时，健康马匹和IBH马匹之间均无差异。然而，在用变应原刺激PBMC后，健康马匹中CD4(+)CD25(+高)和CD4(+)CD25(+低)细胞的FoxP3表达明显高于IBH马匹。向用变应原刺激的健康马匹的PBMC中添加重组IL-4可显著降低CD4(+)CD25(+高)内表达FoxP3的细胞比例。这些结果表明，IBH与变应原诱导的Tregs数量减少有关。这可能是受IBH影响的马匹的PBMC产生IL-4增加的结果。
