四种活化剂对大口黑鲈弹状病毒弱毒冻干疫苗免疫效果的影响OA

This study aimed to identify an optimum diluent to mitigate activity loss during dilution of an attenuated freeze-dried vaccine against Micropterus salmoides rhabdovirus and to enhance its immunogenicity.The study initially evaluated PBS buffer,ginsenosides,β-glucan,astragalus polysaccharide,and scopolamine solutions for diluting and activation of the freeze-dried attenuated virus vaccine.Viral titers(TCID50)were assessed after activation for each group to identify the activator associated with the least titer reduction and the maximum viral activity.Subsequently,the optimal ginsenoside type was identified by evaluating the effects of different ginsenosides on the dilution and activation of the freeze-dried vaccine.Ultimately,each group receiving diluted and activated vaccine formulations was administered to Micropterus salmoides to assess in vivo vaccine efficacy and quantify immune-related parameters,including expression levels of interferon-γ(IFN-γ)and interleukin-12(IL-12).The results indicated that ginsenoside Rg1-activated lyophilized vaccines exhibited the highest viral titers,effectively maintaining viral activity.When the vaccine was diluted with 20 mg/mL ginsenoside Rg1 and administered by immersion,the relative immune protection rate in bass reached 97.6%.The ginsenoside Rg1-diluted and activated freeze-dried vaccination group significantly increased the expression levels of immune-related cytokines IFN-γ and IL-12 in the spleen,head kidney,and gill tissues.Expression peaked at 12 h in spleen tissue(IFN-γ and IL-12 increased by 20.05-fold and 230.64-fold,respectively),at 48 h in head kidney tissue(IFN-γ increased by 21.22-fold),and at 4 h in gill tissue(IL-12 increased by 384.87-fold).In summary,the use of 20 mg/mL ginsenoside Rg1 as the dilution activator for the MSRV 0509 live attenuated freeze-dried vaccine markedly enhances immunogenicity following immersion immunization,indicating strong application potential.