Løvoll Marie, Dalmo Roy A, Bøgwald Jarl
Department of Marine Biotechnology, Norwegian College of Fishery Science, University of Tromsø, 9037, Tromsø, Norway.
Fish Shellfish Immunol. 2007 Oct;23(4):721-31. doi: 10.1016/j.fsi.2007.01.019. Epub 2007 Feb 1.
The components of activated complement display a wide range of functions in inflammatory reactions, including chemotaxis, opsonisation and the destruction of microorganisms. In fish, the complement system is believed to be more complex than in mammals. Teleost fish possess several complement components encoded by multiple genes giving rise to complement subtypes, such as C3-1, C3-3 and C3-4. Complement synthesis is mainly localised in the liver and little attention has been paid to studying production at extrahepatic sites in fish. In mammalian species, the monocyte-macrophage lineage is known to be an important contributor to extrahepatic C3 levels. In vitro studies of piscine macrophages have, however, revealed absence of basal transcription of C3. The objective of this study was to quantify and localise the C3 and C7 subtypes, C4, C5 and factor B in rainbow trout using real-time RT-PCR and in situ hybridisation. Widespread extrahepatic synthesis of all complement components studied was detected, though with high degrees of individual variation between fish. Compared to the levels of complement mRNA in the liver, extrahepatic synthesis was low, but indeed high enough to imply biological significance. This study represents the first comprehensive mapping of the distribution and levels of complement components in any vertebrate species.
活化补体的成分在炎症反应中具有广泛的功能，包括趋化作用、调理作用以及微生物破坏作用。在鱼类中，补体系统被认为比哺乳动物更为复杂。硬骨鱼拥有多个基因编码的几种补体成分，从而产生补体亚型，如C3-1、C3-3和C3-4。补体合成主要定位于肝脏，而对鱼类肝外部位补体产生的研究较少。在哺乳动物中，单核细胞-巨噬细胞系是肝外C3水平的重要贡献者。然而，对鱼类巨噬细胞的体外研究表明，不存在C3的基础转录。本研究的目的是利用实时RT-PCR和原位杂交技术对虹鳟鱼中的C3和C7亚型、C4、C5和B因子进行定量和定位。尽管鱼类之间存在高度的个体差异，但检测到所有研究的补体成分在肝外广泛合成。与肝脏中补体mRNA水平相比，肝外合成较低，但确实高到足以暗示其生物学意义。这项研究是对任何脊椎动物物种中补体成分的分布和水平进行的首次全面测绘。
