Ascending placentitis is a leading cause of abortion in the horse, but adaptive immune response to this disease is unknown. To evaluate this, sub-acute placentitis was experimentally-induced via trans-cervical inoculation of S. zooepidemicus, and endometrium and chorioallantois was collected 8 days later (n = 6 inoculated/n = 6 control). The expression of transcripts relating to Th1, Th2, Th17, and Treg maturation was assessed via RNASeq. IHC of transcription factors relating to each subtype in the same tissues (Th1: TBX21, Th2: GATA3, Th17: IRF4, Treg: FOXp3). An immunoassay was utilized to assess circulating cytokines (Th1: IFNg, IL-2; Th2: IL-4, IL-5; Th17: IL-17, IL-6; Treg: IL-10, GM-CSF). An increase in Th1 and Th17-related transcripts were noted in the chorioallantois, although no alterations were seen in the endometrium. Th2 and Treg-related transcripts altered in a dysregulated manner, as some transcripts increased in expression while others decreased. Immunolocalization of Th1, Th2, and Th17 cells was increased in diseased chorioallantois, while no Treg cells were noted in the diseased tissue. Secreted cytokines relating to Th1 (IFNg, IL-2), Th17 (IL-6), Th2 (IL-5), and Treg (IL-10) populations increased in maternal circulation eight days after inoculation. In conclusion, the Th1/Th17 response to ascending placentitis occurs primarily in the chorioallantois, indicating the adaptive immune response to occur in fetal derived placental tissue. Additionally, ascending placentitis leads to an increase in the helper T cell populations (Th1/Th17/Th2) while decreasing the Treg response. This increase in Th17-related responses alongside a diminishing Treg-related response may precede or contribute to fetal demise, abortion, or preterm labor.

上升胎盘炎是马流产的主要原因，但对该疾病的适应性免疫反应尚不清楚。为了评估这一点，亚急性胎盘炎是通过经宫颈接种兽疫链球菌实验诱导的，8 天后收集子宫内膜和尿囊绒毛膜（n = 6 接种/n = 6 对照）。通过 RNASeq 评估与 Th1、Th2、Th17 和 Treg 成熟相关的转录本的表达。与相同组织中每个亚型相关的转录因子的 IHC（Th1：TBX21、Th2：GATA3、Th17：IRF4、Treg：FOXp3）。免疫测定用于评估循环细胞因子（Th1：IFNg、IL-2；Th2：IL-4、IL-5；Th17：IL-17、IL-6；Treg：IL-10、GM-CSF）。在尿囊绒毛膜中观察到 Th1 和 Th17 相关转录物的增加，尽管在子宫内膜中没有看到变化。Th2 和 Treg 相关转录物以失调的方式改变，因为一些转录物的表达增加而其他转录物减少。Th1、Th2 和 Th17 细胞的免疫定位在患病绒毛膜尿囊炎中增加，而在患病组织中未发现 Treg 细胞。接种 8 天后，与 Th1（IFNg、IL-2）、Th17（IL-6）、Th2（IL-5）和 Treg（IL-10）群体相关的分泌细胞因子在母体循环中增加。总之，对上行胎盘炎的 Th1/Th17 反应主要发生在尿囊绒毛膜中，表明适应性免疫反应发生在胎儿源性胎盘组织中。此外，上行胎盘炎导致辅助 T 细胞群 (Th1/Th17/Th2) 增加，同时降低 Treg 反应。