[Inactivated vaccine for hemorrhage of Grass carp up-regulates the expressions of major immune-related genes in spleen of Grass carp].

OBJECTIVE: To investigate the impact of the injection of inactivated vaccine for hemorrhage of Grass carp on the expressions of main immune-related genes in spleen including immunoglobulin M (IgM), major histocompatibility complexI(MHC I), interferon I(IFN1), complement 3 (C3), interleukin-1β (IL-1β) and intelectin genes.

METHODS: Ctenopharyngoden idellus kidney (CIK) cells were inoculated with Grass carp reovirus (GCRV). Then inactivated vaccine was prepared by inactivating virus suspension with formaldehyde. Vaccine was 50- and 100-times diluted with normal saline. The experiments included four groups: undiluted group, 50-times diluted group, 100-times diluted group and normal saline control group. Then healthy Grass carps with the average body mass (20 ± 5) g were intraperitoneally injected with vaccine or normal saline separately for each group. Spleens were collected at different time points after injection (0, 6, 12, 24, 72 hours) and total RNA extraction was performed immediately. Real-time quantitative PCR (qRT-PCR) was used to detect mRNA expressions of the six immune-related genes.

RESULTS: Compared with normal saline control group, inactivated vaccine injection increased mRNA expressions of the six immune-related genes in the spleen of Grass carp, indicating that the vaccine stimulated the Grass carp to generate non-specific and specific immune responses. In the immunized groups, relative expressions of the genes intelectin, MHCI, IL-1β, C3 were all up-regulated at first and then declined as time went on. Relative expression of IFNIgene reached the peak at 6 hours post-injection and then decreased gradually to the normal level. Differently, relative expression of IgM gene increased continuously within 0-72 hours post-injection.

CONCLUSION: The expressions of the six major immune-related genes were all up-regulated in the spleen of Grass carp injected with different doses of inactivated vaccine for hemorrhage of Grass carp.