van de Braak C B T, Botterblom M H A, Taverne N, van Muiswinkel W B, Rombout J H W M, van der Knaap W P W
Fish Culture and Fisheries Group, Wageningen Institute of Animal Science, Wageningen University, The Netherlands.
Fish Shellfish Immunol. 2002 Oct;13(4):293-309. doi: 10.1006/fsim.2002.0409.
In order to study the reaction of Penaeus monodon haemocytes, live Vibrio anguillarum bacteria were injected and the shrimp were periodically sampled. Immuno-double staining analysis with specific antisera against the haemocyte granules and bacteria showed that large numbers of haemocytes encapsulated the bacteria at the site of injection. A rapid decrease of live circulating bacteria was detected in the haemolymph. Bacterial clearance in the haemolymph was induced by humoral factors, as observed by agglutinated bacteria, and followed by uptake in different places in the body. Bacteria mainly accumulated in the lymphoid organ (LO), where they, or their degradation products, could be detected for at least 7 days after injection. The LO consists of folded tubules with a central haemal lumen and a wall, layered with cells. The haemolymph, including the antigens, seemed to migrate from the central tubular lumen through the wall, where the bacteria are arrested and their degradation is started. Electron microscopy of the LO revealed the presence of many phagocytic cells that morphologically resemble small-granular haemocytes. It is proposed that haemocytes settle in the tubule walls before they phagocytose. Immunostaining suggests that many of the haemocytes degranulate in the LO, producing a layer of fibrous material in the outer tubule wall. These findings might contribute to the reduced haemocyte concentration in the haemolymph of diseased animals or following injection of foreign material. It is proposed that the LO is a filter for virtually all foreign material encountered in the haemolymph. Observations from the present study are similar to clearance mechanisms in the hepatic haemolymph vessel in most decapod crustaceans that do not possess a LO. The experimental shrimp appeared to contain many LO spheroids, where bacterial antigens were finally observed as well. It is proposed that the spheroids have a degradation function for both bacterial and viral material, and that their presence is primarily related to the history of the infectious burden of the shrimp.
为了研究斑节对虾血细胞的反应，将鳗弧菌活菌注射到虾体内，并定期对虾进行采样。用针对血细胞颗粒和细菌的特异性抗血清进行免疫双染分析表明，大量血细胞在注射部位包裹了细菌。在血淋巴中检测到循环活菌数量迅速下降。血淋巴中的细菌清除是由体液因子诱导的，如观察到的细菌凝集现象，随后细菌在体内不同部位被摄取。细菌主要积聚在淋巴器官（LO）中，注射后至少7天在该器官中可检测到细菌或其降解产物。淋巴器官由带有中央血腔和壁的折叠小管组成，壁由细胞分层构成。包括抗原在内的血淋巴似乎从中央小管腔穿过壁迁移，细菌在壁处被捕获并开始降解。淋巴器官的电子显微镜检查显示存在许多吞噬细胞，其形态类似于小颗粒血细胞。有人提出血细胞在吞噬之前先沉积在小管壁上。免疫染色表明许多血细胞在淋巴器官中脱颗粒，在外小管壁上形成一层纤维物质。这些发现可能有助于解释患病动物或注射异物后血淋巴中血细胞浓度降低的现象。有人提出淋巴器官实际上是血淋巴中遇到的所有异物的过滤器。本研究的观察结果与大多数没有淋巴器官的十足目甲壳动物肝血淋巴血管中的清除机制相似。实验虾似乎含有许多淋巴器官球体，在其中也最终观察到了细菌抗原。有人提出这些球体对细菌和病毒物质都具有降解功能，并且它们的存在主要与虾的感染负担历史有关。
