Departamento de Bioquímica, Facultad de Medicina Universidad Nacional Autónoma de México, Mexico City, Mexico.
Departamento de Bioquímica, Facultad de Medicina Universidad Nacional Autónoma de México, Mexico City, Mexico.
Fish Shellfish Immunol. 2019 Nov;94:10-16. doi: 10.1016/j.fsi.2019.08.061. Epub 2019 Aug 26.
In crustaceans, it has been suggested that specific protection against pathogens could be triggered by vaccines and biological response modifiers; although the specific mechanisms of this protection have not been clarified yet. In the crayfish Cherax quadricarinatus, a humoral lectin (CqL) binds its own granular hemocytes through a specific receptor (CqLR) and increases the production of reactive oxygen species (ROS). In the present study, we challenged in vivo crayfishes with immunostimulants, β-glucan (200 μg/kg) or LPS (20 μg/kg), and identified the participation of cellular and humoral mechanisms. The stimulants generated a complex modification in the total hemocytes count (THC), as well as in the proportion of hemocyte subsets. At 2 h after the challenge, the largest value in THC was observed in either challenged crayfishes. Furthermore, at the same time, hyaline hemocytes were the most abundant subset in the hemolymph; after 6 h, granular hemocytes (GH) were the most abundant hemocyte subset. It has been observed that a specific subset of GH possesses a CqLR that has been related to ROS production. After 2 and 6 h of the β-glucan challenge, a significant increase in CqLR expression was observed in the three circulating hemocyte subsets; also, an increased expression of CqL was detected in a granular hemocytes sub-population. After 2 and 6 h of stimulation, the specific activity of the serum lectin challenged with β-glucan was 250% and 160% higher than in the LPS-treated-group, respectively (P < 0.05). Hemocytes from challenged crayfishes were stimulated ex vivo with CqL, ROS production was 180% higher in hemocytes treated with β-glucan + CqL than in hemocytes treated with LPS + CqL (P < 0.05). The results evidence the effectivity of immune stimulators to activate specific crayfish defense mechanisms, the participation of CqL and its receptor (CqLR) could play an important role in the regulation of immune cellular functions, like ROS production, in Cherax quadricarinatus.
在甲壳类动物中，已经有人提出疫苗和生物反应调节剂可以引发针对病原体的特定保护；尽管这种保护的确切机制尚未阐明。在小龙虾 Cherax quadricarinatus 中，一种体液凝集素（CqL）通过特定受体（CqLR）与自身颗粒状血细胞结合，并增加活性氧物质（ROS）的产生。在本研究中，我们用免疫刺激剂β-葡聚糖（200μg/kg）或 LPS（20μg/kg）体内挑战小龙虾，并确定了细胞和体液机制的参与。这些刺激物使总血细胞计数（THC）以及血细胞亚群的比例发生复杂变化。在挑战后 2 小时，在任一受挑战的小龙虾中，THC 值达到最大。此外，在同一时间，透明血细胞是血淋巴中最丰富的血细胞亚群；6 小时后，颗粒状血细胞（GH）是最丰富的血细胞亚群。已经观察到 GH 的一个特定亚群具有与 ROS 产生相关的 CqLR。在β-葡聚糖挑战后的 2 和 6 小时，三个循环血细胞亚群中 CqLR 的表达显著增加；同时，在一个颗粒状血细胞亚群中也检测到 CqL 的表达增加。在刺激后的 2 和 6 小时，用β-葡聚糖挑战的血清凝集素的比活性分别比 LPS 处理组高 250%和 160%（P<0.05）。从受挑战的小龙虾中分离出的血细胞在体外用 CqL 刺激，用β-葡聚糖+CqL 处理的血细胞比用 LPS+CqL 处理的血细胞的 ROS 产生增加了 180%（P<0.05）。结果表明免疫刺激剂可以有效地激活特定的小龙虾防御机制，CqL 及其受体（CqLR）的参与可能在调节 Cherax quadricarinatus 的免疫细胞功能（如 ROS 产生）方面发挥重要作用。
