The Immunological Mechanism Of CVC1302/CVC1303 To Inactivated Vaccine Of Porcine Epidemic Diarrhea Virus

Viral infectious diseases have caused worldwide serious losses to livestock farming.Currently,vaccination is the most effective means of controlling infectious diseases.Although vaccination according to immunization procedures,in many cases livestock are still unable to produce effective immune responses.Therefore,the use of immune enhancers accompanied by immunization has become one of the important means to improve the immune efficacy of vaccines.In this study,mice immune models were used to explore the vaccine immune response of enhancing agent CVC1302 on porcine epidemic diarrhea inactivated vaccine,and to study the mucosal immune response effects of agent CVC1303 on porcine epidemic diarrhea inactivated vaccine,which provided the important experimental reference to the further development of the immune enhancing agent.The main experimental research and results obtained are as following.1.The immune enhancement of enhancer CVC1302 on porcine epidemic diarrhea inactivated vaccine in immunized miceThe aim of the present study was to exploration the effects of immunopotentiator CVC1302 on the immune response to PEDV vaccine including humoral immunity,cellular immunity and cytokines in vivo.Mice were subcutaneously injected with PEDV Vaccine and three dosages CVC1302,and vaccine only and PBS group were used as control.On 30th day after the second immunization,blood samples were collected to measure PEDV-specific IgG titers and IgG subclasses,and lymphocytes were isolated to detect the lymphocyte proliferation,T cell subtype distribution and intracellular cytokine levels(IL-4,IL-6,IL-10,IL-12,IFN-?,and TNF-?),and expressions of co-stimulatory molecule CD86,CD80,CD40 and MHC-?.The results showed that compared with that of vaccine only,CVC1302 at high dosage significantly enhanced PEDV-specific IgG antibody and IgG1 and IgG2a subtype level,while CVC1302 at middle dosage significantly enhanced PEDV-specific IgG antibody and IgG1 subtype level.Furthermore,PEDV vaccine immunization with high dosage CVC1302 produced the significantly increased splenocyte proliferation,T cell subtype distribution and Thl and Th2 related cytokine productions.and stimulated the dendritic cells maturation.These results suggested that the immunopotentiator CVC1302 could effectively improve the immune responses to PEDV inactivated vaccine,which provide an experimental basis for the development of new and enhanced immune responses to vaccine,and provide a scientific basis for improving the clinical immune efficacy and improving the immune function of vaccines.2.The immunological mechanism of CVC1303 to inactivated vaccine of porcine epidemic diarrhea virusThe aim of the present study was to exploration the effects of immunopotentiator CVC1303 on the immune response and mucosal immune to PEDV Vaccine in mice.Mice were subcutaneously injected with PEDV vaccine and three dosages CVC1303,and vaccine only and PBS group were used as control.On 30trh day after the second immunization,blood samples were collected to measure PEDV-specific IgG titers and IgG subclasses,and lymphocytes were isolated to detect T cell subtype distribution and intracellular IL-4 and IL-6 cytokine levels,and expressions of co-stimulatory molecule on dendritic cells.Small intestinal and lung washings were collected 30d and 47d after the second immunization to measure PEDV-specific IgA titers,and SP immunohistochemical method staining was employed to analyze the changes of IgAA+ positive cells in mice small intestinal.The results showed that compared with that of vaccine only,mice immunized PEDV vaccine and three dosages CVC1303 produced the significantly increased PEDV-specific IgG and IgGl antibody levels and cytokines productions,and elicited significantly CD3+CD4+T cells subpopulation and expressions of co-stimulatory molecule on dendritic cells.Moreover,our findings demonstrated that high dose CVC1303 significantly enhanced PEDV-specific IgA antibody titers in small intestinal and lung.There results suggested that immunopotentiator CVC1303 could effectively improve the PEDV-specific immune responses and mucosal immune,which provide an experimental basis for the development of new adjuvant agents to promote mucosal immune response.