The Immunological Functions of Muramyl Dipeptide Compound Adjuvant on Humoral, Cellular-mediated and Mucosal Immune Responses to PEDV Inactivated Vaccine in Mice.

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 mice. 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 response.

A bursal pentapeptide (BPP-I), a novel bursal-derived peptide, exhibits antiproliferation of tumor cell and immunomodulator activity.

The bursa of Fabricius (BF) is the central humoral immune organ unique to birds. Here, we isolated a novel bursal pentapeptide I (BPP-I), LGPGP, from BF. BPP-I could play inhibition effect on MCF-7 but not on CEF or Vero cell proliferation in vitro, and enhance antitumor factor p53 protein expression. Also, BPP-I stimulated antibody production in a dose-dependent manner in hybridoma cell. Furthermore, BPP-I could induce various immune responses in mice immunization experiments, including increase antibody production and cytokines IL-4 and IFN-γ level, and induce T-cell immunophenotyping. These results suggest that BPP-I is a potential immunomodulator of antitumor and immunity. The study could provide some novel insights on the probable candidate reagent for the antitumor and immune improvement.