柱状黄杆菌胞外多糖对草鱼的免疫促进作用

Immunologic enhancement of Flavobacterium columnare exopolysaccharide in grass carp,Ctenopharyngodon idellus

将柱状黄杆菌胞外多糖(EPS)溶液经腹腔注射免疫草鱼,以注射灭菌生理盐水作对照。免疫一周后,分别提取受免鱼与对照鱼肝脏、脾脏、体肾和头肾4种组织中的总RNA,并通过RT-PCR半定量的方法检测不同组织中C-反应蛋白(CRP)、白介素1(IL-1)、主要组织相容性复合体I(MHC I)、免疫球蛋白M(IgM)、干扰素(IFN)等5种免疫基因的表达情况。结果显示,CRP在受免鱼肝脏中的表达显著上升;MHC I在受免鱼脾脏、体肾中的表达显著下降;IgM在受免鱼4种组织中的表达皆显著上升;IL-1在受免鱼4种组织中的表达与对照组没有显著差异;无论受免组还是对照组都只能检测到微弱的IFN表达,且两组之间没有显著差异。结果表明,柱状黄杆菌EPS对草鱼的先天免疫能力以及特异性体液免疫能力具有促进作用。

The immunologic enhancement of Flavobacterium columnare exopolysaccharide （EPS） was examined by semi-quantitative RT-PCR in grass carp （ Ctenopharyngodon idellus ） immurfized with intraperitoneal injection of EPS. The total RNA was extracted from liver, spleen, tnmk and head kidney of EPS- and saline-injected fish and reverse-transcribed into cDNA, respectively. Five immune genes, i.e. CRP, IL-1, MHC I, IgM and IFN were then amplified through polymerase chain reaction and semi-quantified by comparing brighmess of electrophoresis band of the gene PCR product with that of β-actin, respectively. The gene expression of CRP in liver of immunized fish increased significantly, and gene expression of MHC I in spleen and tnmk kidney of immunized fish decreased significantly in comparison with control fish. No significant change was observed in the gene expression of IL-1 between immunized and control fish, and the gene expression of IFN was weakly detected in tissues of both immunized and control fish with no significant difference observed. However, the gene expression of IgM in four tissues of immunized fish increased significantly when compared with control fish. It is thus indicated that the innate and specific humoral immunity of grass carp are effectively activated by immunization with EPS of F. columnare.