Department of Marine Science, Chulalongkorn University, Thailand.
Dev Comp Immunol. 2010 Jan;34(1):19-28. doi: 10.1016/j.dci.2009.07.007. Epub 2009 Aug 7.
In all previous studies, to study shrimp immune response, bacteria were directly injected into the shrimp body and as a consequence the initial step of a natural interaction was omitted. In this study we have instead used an immersion technique, which is a more natural way of establishing an infection, to study immune responses in black tiger shrimp (Penaeus monodon). Normally, Vibrio harveyi (Vh) is highly pathogenic to post-larval shrimp, but not to juveniles which usually resist an infection. In post-larvae, Vh causes a massive destruction of the digestive system, especially in the hepatopancreas and in the anterior gut. We have therefore investigated changes in transcription levels of fifteen immune-related genes and morphological changes in juvenile shrimp following an immersion of shrimp in Vh suspension. We found that a pathogenic bacterium, Vh, has the capacity to induce a local expression of some immune-related genes in shrimp after such a bacterial immersion. Our results show that in the juvenile gut small changes in expression of the antimicrobial peptide (AMP) genes such as antilipopolysaccharide factor isoform 3, crustin and penaeidin were observed. However some other genes were more strongly induced in their expression compared to the AMP genes. C-type lectin, Tachylectin 5a1 and mucin-like peritrophic membrane were increased in their expression and the C-type lectin was affected most in its expression. Several other examined genes did not change their expression levels. By performing histology studies it was found that Vh infection induced a strong perturbation of the midgut epithelium in some regions. As a consequence, the epithelial cells and basement membrane of the infected site were completely damaged and necrotic and massive hemocyte infiltration occurred underneath the affected tissue to combat the infection.
在之前的所有研究中，为了研究虾的免疫反应，细菌被直接注射到虾体内，因此省略了自然相互作用的初始步骤。在这项研究中，我们使用了一种浸泡技术，这是一种更自然的感染建立方式，来研究斑节对虾（Penaeus monodon）的免疫反应。通常，哈维弧菌（Vibrio harveyi，Vh）对幼虾具有高度致病性，但对幼虾没有致病性，幼虾通常能抵抗感染。在幼虾中，Vh 会导致消化系统的大量破坏，尤其是在肝胰腺和前肠中。因此，我们研究了在幼虾浸泡在 Vh 悬浮液后，十五种免疫相关基因的转录水平变化和形态变化。我们发现，一种致病性细菌 Vh 在这种细菌浸泡后，有能力诱导虾体内某些免疫相关基因的局部表达。我们的结果表明，在幼虾的肠道中，观察到一些抗菌肽（antimicrobial peptide，AMP）基因如抗脂多糖因子异构体 3、壳聚糖和 penaeidin 的表达有小的变化。然而，与 AMP 基因相比，其他一些基因的表达被更强地诱导。C 型凝集素、Tachylectin 5a1 和类几丁质围食膜的表达增加，C 型凝集素的表达受影响最大。其他一些被检查的基因没有改变它们的表达水平。通过进行组织学研究发现，Vh 感染在一些区域引起了中肠上皮的强烈扰动。因此，受感染部位的上皮细胞和基膜完全受损和坏死，大量的血细胞浸润发生在受影响的组织下，以对抗感染。
