Prostaglandins (PGs) are lipid mediators derived from arachidonic acid by several enzymes including cyclooxygenase (COX)-1 and COX-2. We have previously shown that PGE₂ regulates immune responses, such as Th1 cytokine production and T-cell proliferation, in cattle. However, it is still unclear whether other PGs are involved in the regulation of immune responses in cattle.

Here, immunosuppressive profiles of PGs (PGA₁, PGB₂, PGD₂, PGE₂, PGF_1α and PGF_2α) were firstly examined using bovine peripheral blood mononuclear cells (PBMCs). In addition to PGE₂, PGA₁ significantly inhibited Th1 cytokine production from PBMCs in cattle. Further analyses focusing on PGA₁ revealed that treatment with PGA₁ in the presence of concanavalin A (con A) downregulated CD69, an activation marker, and IFN-γ expression in both CD4⁺ and CD8⁺ T cells. Sorted CD3⁺ T cells stimulated with con A were cultivated with PGA₁, and IFN-γ and TNF-α concentrations decreased upon PGA₁ treatment. Taken together, these results suggest that the treatment with PGA₁ in vitro inhibits T-cell activation, especially Th1 cytokine production, in cattle.

前列腺素 (PG) 是通过多种酶（包括环氧合酶 (COX)-1 和 COX-2）衍生自花生四烯酸的脂质介质。我们之前已经表明，PGE ₂可调节牛的免疫反应，例如 Th1 细胞因子的产生和 T 细胞增殖。然而，尚不清楚其他 PGs 是否参与了牛免疫反应的调节。

此处，首先使用牛外周血单核细胞 (PBMC) 检查PG（PGA ₁、PGB ₂、PGD ₂、PGE ₂、PGF _1α和 PGF _{2α ）的免疫抑制特征。}除了 PGE ₂之外，PGA ₁还显着抑制了牛 PBMC 中 Th1 细胞因子的产生。针对 PGA ₁的进一步分析表明，在伴刀豆球蛋白 A (con A) 存在的情况下，用 PGA ₁处理会下调 CD69（一种激活标记物）和 CD4 ⁺和 CD8 ⁺ T 细胞中的 IFN-γ 表达。分选 CD3 ⁺用 con A 刺激的 T 细胞用 PGA ₁培养，IFN-γ 和 TNF-α 浓度在 PGA ₁处理后降低。总之，这些结果表明，在体外用 PGA ₁ 处理可抑制牛的 T 细胞活化，尤其是 Th1 细胞因子的产生。