Efficacy of Rg1-Oil Adjuvant on Inducing Immune Responses against Bordetella bronchiseptica in Rabbits

In vitro evaluation of ginsenoside Rg1 immunostimulating effect in bovine mononuclear cells

The aim of this study was to evaluate the immunomodulatory effect of ginsenoside Rg1 on mammary secretion and peripheral blood mononuclear cells (MSMC and PBMC, respectively). The mRNA expression of TLR2, TLR4 and selected cytokines were evaluated on MSMC after Rg1 treatment. Also, TLR2 and TLR4 protein expression was evaluated on MSMC and PBMC after Rg1 treatment. Phagocytic activity and capacity, ROS production and MHC-II expression were evaluated on MSMC and PBMC after Rg1 treatment and co-culture with Staphylococcus aureus strain 5011. Rg1 induced mRNA expression of TLR2, TLR4, TNF-α, IL-1β, IL-6 and IL-8 in groups treated with different concentrations and at different times in MSMC, and induced TLR2 and TLR4 protein expression in MSMC and PBMC. Rg1 increased phagocytic capacity and ROS production in MSMC and PBMC. Rg1 increased MHC-II expression by PBMC. However, Rg1 pre-treatment had no effect on cells co-cultured with S. aureus. In conclusion, Rg1 was able to stimulate several sensing and effector activities in these immune cells.

Safety and Efficacy of the Bordetella bronchiseptica Vaccine Combined with a Vegetable Oil Adjuvant and Multi-Omics Analysis of Its Potential Role in the Protective Response of Rabbits

Infectious respiratory diseases caused by Bordetella bronchiseptica (Bb) are seriously endangering the development of the rabbit industry in China. Unfortunately, no licensed vaccines are available for this pathogen. The present study was designed to determine whether the inactivated Bb antigen formulated with vegetable oil adjuvant (named E515) which contains soybean oil, vitamin E, and ginseng saponins, functions as a safe and effective vaccine (E515-Bb) against Bb infection in rabbits. Based on local and systemic reactions, both the E515 adjuvant alone and the E515-Bb vaccine exhibited good safety in rabbits. Immune response analysis implies that rabbits immunized with the E515-Bb vaccine produced significantly higher, earlier, and longer-lasting specific antibody responses and activated Th1/Th2/Th17 cell responses than those immunized with the aluminum hydroxide (Alum)-adjuvanted Bb vaccine (Alum-Bb) or Bb antigen alone. Moreover, the E515-Bb vaccine effectively protected rabbits from Bb infection. Additionally, integrated multi-omics analysis revealed that the immunoprotective effect of the E515-Bb vaccine was achieved through upregulation of the complement and coagulation cascades and cell adhesion molecule (CAM) pathways, and the downregulation of the P53 pathway. Overall, these results indicate that the E515-Bb vaccine is safe, elicits an efficient immune response and provides good protection against Bb infection in rabbits. Thus, the E515-adjuvanted Bb vaccine can be considered a promising candidate vaccine for preventing Bb infection.

A New Nano Adjuvant of PF3 Used for an Enhanced Hepatitis B Vaccine

Recombinant protein vaccines, with highly pure ingredients and good safety, are gradually replacing some attenuated and inactivated vaccines in clinical practice. However, since their low immunogenicity of the recombinant proteins, adjuvants are often needed to enhance immune response after vaccination. Aluminum adjuvant has been widely used in some vaccines for decades, it can induce strong humoral immunity, but the deficiency of cellular immunity limits its application for some vaccines. Therefore, it is urgently needed to develop novel adjuvant to increase not only humoral but also cellular immune response. To address this, we designed and prepared a new nano adjuvant (PF3) through microfluidization by the combination of saponin (Ginsenoside Rg1) and oil-in-water nano emulsion (NE) in the present study. As compared to aluminum adjuvant, PF3 had stronger humoral and cellular immune induction effect because of high cellular uptake and activization of immune response pathways. Furthermore, PF3 showed better immune enhancement and acceptable biosafety equivalent to that of aluminum adjuvant. In addition, no obvious changes of PF3 were observed in size and zeta potential after 12 weeks storage at 4 and 37°C, demonstrating its high stability in vitro. This study provided an adjuvant platform to replace traditional aluminum adjuvant in design of recombinant vaccines.