Immune Protection Of Vibrio Mimicus Inactivated Vaccine In Pelteobagrus Fulvidraco

In previous study,we found that the Vibrio mimicus has cause a server skin ulceration disease in the yellow catfish(Pelteobagrus fulvidraco)and channel catfish(Ietalurus Punetaus)from 2011 in south China.Without any effective control measures,this high infection rate and mortality disease has cause severe economic harm to the catfish aquaculture.In this study,the Vibrio mimicus which was isolated from the yellow catfish was inactivated by formalin to make the vaccine.We vaccinate the yellow cat fish by intraperitoneal injection and immersion inoculation.to investigate the immune protection of this vaccine,the vaccine protection test was carried out,also the transcriptome of yellow catfish spleen in 1×10~9CFU/mL intraperitoneal injection group and control group has been characterized by using Illumina paired-end platform to identify putative gene involved in immunity.The main results are as follows.(1)The Vibrio mimicus stain which was isolated from yellow catfish was recovered,cultivated and inactive by 5%formalin.The inactived bacterial fluid was diluted to desired concentration and mixed with Freund's adjuvant to make the vaccines.The vaccines showed stability and safety of the yellow catfish.(2)Two concentration of the vaccines and two Soaking time has been test in the immersion inoculation experiment.Two weeks after vaccination,we repeat the step to strengthen the immune reaction.but the vaccines by immersion inoculation show no effect in the protection experiment in four weeks after vaccination.(3)Using 1×10~9CFU/mL,1×10~7CFU/mL and 1×10~5CFU/mL this three dose of vaccine in the injection immunization experiment.The first immunity was using the vaccine with Freund's complete adjuvant.The second immunity was using the same dose of vaccine with Freund's incomplete adjuvant in two weeks after the first immunity.The 1×10~9CFU/mL group show 100%production rate in the protection experiment in4 and 8 weeks after the first immunity,but the protection experiment in 6 weeks after the first immunity which using the high infection dosage,the 1×10~9CFU/mL group show only 23%production rate.The other two experiment group showed lower production rate than the 1×10~9CFU/mL group.(4)In the four weeks after injection immunization,the transcriptome of the yellow catfish spleen in the 1×10~9CFU/m L group and the control group has been characterized by using Illumina paired-end platform.Compare to the control group,the expression of 1519 genes has change in the experimental group,such as the immune related genes like MHC I,MHC II,C7,Hsp75 and Hsp90.In conclusion,the inactivated Vibrio mimicry vaccine can effective protects the yellow catfish from the Vibrio mimicry,and the effect is immune dose dependent.However,this protection cannot tolerate the high toxic doses.Beside,the vaccine can regulate the expression of yellow catfish immune related genes.