College of Life Science, Henan Normal University, Henan province, PR China; Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan province, PR China.
Engineering Lab of Henan Province for Aquatic Animal Disease Control, College of Fisheries, Henan Normal University, Henan province, PR China.
Fish Shellfish Immunol. 2023 Feb;133:108550. doi: 10.1016/j.fsi.2023.108550. Epub 2023 Jan 13.
CD3γ/δ found in non-mammalian vertebrates is a CD3 homolog with structural characteristics similar to both mammalian CD3γ and CD3δ, and plays important roles in T cell recognization and immune response in fish. In this study, the full-length of CD3γ/δ from Qihe crucian carp (named CaCD3γ/δ) was cloned and characterized, then the expression response profiles and potential immune functions was explored after Aeromonas veronii and Poly(I:C) challenge. The results showed that the full-length of CaCD3γ/δ was 819 bp including a 5'-UTR of 141 bp, a 3'-UTR of 168 bp, and an ORF of 510 bp encoding a putative 169-aa protein with an estimated MW of 18.71 kD and a theoretical pI of 8.77. The protein sequence of CaCD3γ/δ contained a Leu-Leu and a CXXXC motif in the extracellular domain, and an ITAM and a Leu-Ile motif in the cytoplasm, and a residue of Asn in the transmembrane. CaCD3γ/δ was constitutively expressed in the spleen, liver, gill, and blood of Qihe crucian carp. After the carp were challenged with Poly(I:C) and Aeromonas veronii, the mRNA expression levels of CaCD3γ/δ were significantly changed in the spleen, head kidney, intestine and gill, according to the results of qPCR. However, compared with A. veronii, Poly(I:C) challenge can rapidly induce the CaCD3γ/δ expression levels in head kidney, intestine and spleen, which suggested CaCD3γ/δ may be differentially modulated by different pathogens. Moreover, the results of immunohistochemical analysis showed that the CaCD3γ/δ secreted cells in the spleen and gills of Qihe crucian were increased after challenged with Poly(I:C), as well as the spleen challenged with A. veronii, but at different levels. Combined with the fact that vascular congestion, necrosis of parenchymal cells, and inflammatory cells including lymphocytes infiltration were also observed in the gill and spleen of Qihe crucian carp treated with A. veronii and Poly(I:C) revealed by pathological analysis, it was predicted that CaCD3γ/δ T lymphocytes may participated in the immune response against pathogens. This study will contribute to understand the important role of CaCD3γ/δ T lymphocytes in the immune response of Qihe crucian carp, and provide new insights for the prevention and treatment of the diseases of Qihe crucian carp.
在非哺乳动物脊椎动物中发现的 CD3γ/δ 是一种与哺乳动物 CD3γ 和 CD3δ 具有相似结构特征的 CD3 同源物，在鱼类 T 细胞识别和免疫反应中发挥重要作用。本研究克隆并鉴定了淇河鲫（命名为 CaCD3γ/δ）的全长 CD3γ/δ，然后在受到嗜水气单胞菌和 Poly(I:C) 挑战后，探讨了其表达应答谱和潜在的免疫功能。结果表明，CaCD3γ/δ 的全长为 819bp，包括 5'-UTR 为 141bp、3'-UTR 为 168bp 和 ORF 为 510bp，编码一个推测的 169-aa 蛋白，估计 MW 为 18.71kD，理论 pI 为 8.77。CaCD3γ/δ 的蛋白序列在细胞外域包含一个 Leu-Leu 和一个 CXXXC 基序，在细胞质中包含一个 ITAM 和一个 Leu-Ile 基序，以及一个跨膜中的 Asn 残基。CaCD3γ/δ 在淇河鲫的脾脏、肝脏、鳃和血液中持续表达。用 Poly(I:C)和嗜水气单胞菌刺激鲤鱼后，qPCR 结果显示 CaCD3γ/δ 在脾脏、头肾、肠和鳃中的 mRNA 表达水平发生显著变化。然而，与嗜水气单胞菌相比，Poly(I:C) 可迅速诱导头肾、肠和脾脏中 CaCD3γ/δ 的表达水平，这表明 CaCD3γ/δ 可能受到不同病原体的差异调节。此外，免疫组化分析结果表明，用 Poly(I:C) 刺激后，淇河鲫脾脏和鳃中 CaCD3γ/δ 分泌细胞增加，用嗜水气单胞菌刺激脾脏也出现同样情况，但程度不同。结合病理分析发现，用嗜水气单胞菌和 Poly(I:C) 处理淇河鲫后，鳃和脾脏中还观察到血管充血、实质细胞坏死和包括淋巴细胞浸润在内的炎性细胞，这表明 CaCD3γ/δ T 淋巴细胞可能参与了针对病原体的免疫反应。本研究将有助于了解 CaCD3γ/δ T 淋巴细胞在淇河鲫免疫反应中的重要作用，并为淇河鲫疾病的预防和治疗提供新的见解。
