GCRV弱毒疫苗免疫草鱼母本的免疫因子代间传递与表达特性

为探究GCRV弱毒疫苗母源性免疫的草鱼母本及其子代免疫因子(IgM、C3、LSZ)表达特性及代间传递效应,采用ELISA、Rt-q PCR等方法检测了草鱼母本产前40 d接种疫苗后,母本血液、子代早期发育阶段及2月龄幼鱼3种免疫因子的蛋白活性及基因表达水平。结果显示,经GCRV弱毒疫苗免疫的草鱼母本血液、早期胚胎及幼鱼阶段IgM蛋白活性均显著高于对照组样品。子代各阶段中,28日龄的夏花样品IgM蛋白活性水平最高,而5日龄水花样品中蛋白活性最低;从受精卵发育至3日龄水花阶段,实验组样品免疫因子C3和LSZ的蛋白活性均显著高于对照组;2组鱼中IgM、C3和LSZ蛋白的活性水平随着发育进行,总体上呈先下降后升高的趋势,从卵细胞至3日龄水花阶段实验组样品C3和LSZ蛋白活性水平均显著高于对照组。实验组和对照组受精卵IgM基因的表达水平差异最大,实验组表达量为对照组的3.4倍。从24 h器官形成期至3日龄水花样品中,实验组C3基因的表达水平显著高于对照组。从卵细胞至3 h囊胚期阶段,实验组LSZ基因表达水平显著高于对照组。实验组2月龄草鱼体肾、头肾、脾脏组织中IgM基因表达量均显著高于对照组;感染GCRV病毒后,实验组死亡尾数(2尾)低于对照组死亡尾数(5尾)。研究表明母源性免疫可在草鱼进行代间传递,并对子代起到一定程度的免疫保护作用。

The expression and transmission of immune factors between generations in maternal Ctenopharyngodon idella after immunization with GCRV attenuated vaccine

In order to investigate the expression characteristics and transmission effects of immune factors between the female parent and the progeny of Ctenopharyngodon idella, after being vaccinated with GCRV attenuated vaccine to female grass carp (40 days old). the protein activity and gene expression levels of IgM, C3 and LSZ were detected in the blood of female parent during the early development embryos of progeny and juvenile fish. The activities of IgM protein in the blood, early embryos and juvenile stage of grass carp were significantly higher than those in the control group by GCRV attenuated vaccine. In each stage of progeny, the expression level of IgM protein was the highest on d 28, while the protein activity was the lowest on d 5. From the fertilized egg to the 3 d water stage, the protein activity of C3 and LSZ were significantly higher in the experimental group than those in the control group. The activity levels of IgM, C3 and LSZ proteins in both groups showed a trend from decline to rise. The activity levels of C3 and LSZ protein in the experimental group were significantly higher than those in the control group from the stages of egg cell to 3 d. The expression level of IgM gene had a big difference between the experimental group and control group, the expression level of the experimental group was 3.4 times that of the control group. From the period of organogenesis (24 h) to the stage of 3 d, the mRNA expression of C3 was significantly higher than that in the control group. From the egg cell to the blastula stage, the mRNA expression of LSZ was significantly higher than that in the control group. After being immunized by attenuated vaccine of GCRV, the mRNA expressions of IgM were significantly higher than those in the control group in the tissues of body kidney, head kidney and spleen of 2-month-old progeny. The number of death fish caused by the GCRV infection in the experimental group (2 fish died) was lower than that in the control group (5 fish died). The results showed that maternal immunization can transmit between generations, and it played an important role in the immune protection of progeny.