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.