The Application Of ISCOM In Marine Fish

The immune stimulating complex(ISCOM),which can function as immuneadjuvant, is broadly used in producing vaccines for its safety, high-effectiveness andlow side-effect. Though the ISCOM is mainly applied by injection in immunizingpoultry,it can also be given via mucosal route, which makes it an ideal material tomanufacture vaccines for fish use given by feeding and steeping. Yet there's norelevant reports on the use of ISCOM in marine fish.Based on technologies of producing ISCOM, three different immune stimulantswere specially made to immunize large yellow croaker(Pseudosciaena.crocea) in thisresearch:BSA-ISCOM,Vibrio.vulnificus-ISCOM and dried eggyolk produced byVibrio.vulnificus-ISCOM stimulating laying hens.And the impacts of these stimulantson the immune system of large yellow croaker were measured in terms of the activityof',superoxide,ismutase(SOD),complement,C3(C3),lysozyme(LZM),interferon-gamma(INF-γ) and antibody titer in the serum of test subjects.And,a pathogenic challengeposed by V.vulnificus was conducted on test subjects to evaluate the immuneprotection efficiency promoted by ISCOM.Test results of blood samplings of test subjects immunized by BSA-ISCOMshowed that the activity of SOD,LZM,C3,INF-γ and total protein level in the serumwere all significantly higher than those of the control group during the firstsampling(P<0.05),while significant improvements were only observed in the activityof LZM and total protein level in the serum during the second sampling(P<0.05).Andthe immune protection rate of BSA-ISCOM on larger yellow croaker was72.3%.Besides, test results of blood samplings of test subjects immunized byVibrio.vulnificus-ISCOM showed that the activity of SOD,INF-γ and the level ofantibody titer and total protein in the serum were all significantly higher than those ofthe control group during the first sampling(P<0.05),and significant improvements inthe level of antibody titer and total protein in the serum were still observed during thesecond sampling(P<0.05).And immune protection rate of Vibrio.vulnificus-ISCOMon larger yellow croaker was88.4%. And still, test results of blood samplings of test subjects immunized by driedeggyolk produced by Vibrio.vulnificus-ISCOM stimulating laying hens showed thatthe activity of SOD,LZM,INF-γ and the level of antibody titer in the serum were allsignificantly higher than those of the control group during the firstsampling(P<0.05),and significant improvement was only observed in the level ofantibody titer in the serum during the second sampling(P<0.05).And immuneprotection rate of dried eggyolk produced by Vibrio.vulnificus-ISCOM stimulatinglaying hens on larger yellow croaker was46.7%.Meanwhile,the producing of outer membrane proteins OMPA and OMPS ofEdwardsiella.Tarda in Recombinant strains was facilitated.Furthermore,OMPA andOMPS were isolated,purified and made into related ISCOM,which laid thefoundation of the adoption of ISCOM in immunizing marine fish to E.tarda.