Background: The muramyl dipeptide compound adjuvant, CVC1303, was one new resigned
adjuvant to PEDV inactivated vaccine. Exploring the effects of CVC1303 on the immune
induction to PEDV vaccine was of vital importance to the clinical application.
Objectives: Here we explored the functions of CVC1303 on the humoral, cellular and mucosal immune
response to PEDV vaccine in mice immunization.
Methods: Mice were twice subcutaneously injected with PEDV vaccine including high, medium
and low dosages CVC1303, respectively. On 30th day after the second immunization, sera samples
were collected from the immunized mice to measure PEDV-specific IgG and IgG subclasses levels,
and lymphocytes were isolated to detect T cell subtype and intracellular IL-4 and IL-6 cytokine
productions, and the expressions of co-stimulatory molecule on dendritic cells in the immunized
mice. Small intestinal and lung washings were collected on 30th and 47th day after the second immunization
to measure PEDV-specific IgA levels, and SP immunohistochemical method staining
was employed to analyze the deviations of IgA+ positive cells in the small intestinal of the immunized
Results: Our investigation proved the strong regulatory roles of CVC1303 on PEDV-specific IgG
and IgG1 antibody and cytokines productions, and the significant increased CD3+CD4+T cells
subpopulation and expressions of co-stimulatory molecules on dendritic cells in the immunized
mice. Moreover, our findings verified the significantly enhanced PEDV-specific IgA antibody titers
in small intestinal and lung in the mice immunized with PEDV vaccine and CVC1303.
Conclusion: Compound adjuvant CVC1303 could effectively improve the PEDV-specific immune
responses and mucosal immune, which provided an experimental basis for the further clinical application
of new adjuvant CVC1303 and the development of improvement on the mucosal immune