The skin epithelial layer acts as an important immunological barrier against pathogens and is capable of recognizing and responding to pathogen associated molecular patterns (PAMPs) in human and mouse models. Although presumed, it is unknown whether amphibian skin epithelial cells exhibit the ability to respond to PAMPs such as viral double-stranded RNA (dsRNA). To address this, two cell lines from the dorsal skin (Xela DS2) and ventral skin (Xela VS2) of the African clawed frog (Xenopus laevis) were established. Xela DS2 and Xela VS2 cells have an epithelial-like morphology, express genes associated with epithelial cells, and lack senescence-associated beta-galactosidase activity. Cells grow optimally in 70% Leibovitz’s L-15 medium supplemented with 15% fetal bovine serum at 26°C. Upon treatment with poly(I:C), a synthetic viral dsRNA analogue and known type I interferon inducer, Xela DS2 and Xela VS2 exhibit marked upregulation of key pro-inflammatory and antiviral transcripts suggesting frog epithelial cells participate in the recognition of extracellular viral dsRNA and production of local inflammatory signals; similar to human and mouse models. Currently, these are the only known Xenopus laevis skin epithelial-like cell lines and will be important for future research in amphibian epithelial cell biology, initial host-pathogen interactions, and rapid screening of the effects of environmental stressors, including contaminants, on frog skin epithelial cells.

中文翻译：

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Xela DS2和Xela VS2：来自成年非洲爪蛙（Xenopus laevis）的两种新型皮肤上皮样细胞系及其对细胞外病毒dsRNA类似物的反应

皮肤上皮层是抵抗病原体的重要免疫屏障，能够识别和响应人和小鼠模型中的病原体相关分子模式（PAMP）。尽管是推测的，但尚不清楚两栖动物皮肤上皮细胞是否具有对PAMP（例如病毒双链RNA（dsRNA））作出反应的能力。为了解决这个问题，从非洲爪蛙（Xenopus laevis）的背侧皮肤（Xela DS2）和腹侧皮肤（Xela VS2）获得了两个细胞系）成立。Xela DS2和Xela VS2细胞具有上皮样形态，表达与上皮细胞相关的基因，并且缺乏与衰老相关的β-半乳糖苷酶活性。在26°C的70％Leibovitz's L-15培养基中添加15％的胎牛血清，可使细胞最佳生长。用合成病毒dsRNA类似物和已知的I型干扰素诱导剂poly（I：C）处理后，Xela DS2和Xela VS2表现出关键的促炎和抗病毒转录本的明显上调，表明青蛙上皮细胞参与了细胞外病毒dsRNA的识别和产生局部炎症信号；与人类和老鼠模型相似。当前，这些是唯一已知的非洲爪蟾 皮肤上皮样细胞系，对于两栖上皮细胞生物学的未来研究，初始宿主-病原体相互作用以及快速筛选环境应激源（包括污染物）对青蛙皮肤上皮细胞的影响至关重要。