Adjuvant effects of novel water/oil emulsion formulations on immune responses against infectious bronchitis (IB) vaccine in mice.

Vaccines have long made use of adjuvants to boost the immune response of the body and reduce the amount of vaccine needed as well as the expense of producing the vaccine. Many vaccine adjuvants are in development, but their application in veterinary vaccinations is restricted due to their lack of efficacy or undesirable side effects. For this reason, it is essential to develop novel adjuvants. To address the issue that the currently available infectious bronchitis (IB) vaccine often fails to produce sufficient immune responses, Coral Biotechnology tested two of their newly developed water-in-oil (W/O) type emulsion adjuvants (Coralvac RZ 528 and Coralvac RZ 506) in the IB vaccine. These adjuvants were tested in a mouse model to determine whether it worked with an inactive IBV H120 vaccine. Vaccine formulations were prepared by combining a virus concentration of 1 × 106 EID50/0.1 ml with an emulsion of the W/O type in a specific ratio. Once the formulations were ready, it was injected intramuscularly as a single dosage, and the mice were monitored for 21 days afterwards. The results showed that anti-IB antibody titer (IgG and IgG1), CD3+ CD8+ T cell responses as well as IFN- γ cytokine production, and splenocyte proliferation were all considerably higher in the IBV H120 with Coralvac RZ 528 and IBV H120 with Coralvac RZ 506 formulation groups than in the viral control group. According to our findings, the humoral and cellular immune responses of mice were significantly enhanced by these novel vaccine adjuvants. Thus, our results provide evidence that the W/O type emulsion adjuvants developed by Coral Biotechnology may be a useful adjuvant in IBV vaccines.

Single and repeat-dose toxicity and local tolerance assessment of newly developed oil emulsion adjuvant formulations for veterinary purposes.

Adjuvants are components of vaccines that boost the intensity, duration, and breadth of the immune response. Insight into the mechanisms responsible for the immunotoxicity of both local and systemic adverse reactions following the use of adjuvants has been gained through research over the past twenty years. In the present study, single and repeated-dose toxicity and local tolerance of newly developed Water-in-Oil (W/O) and Water-in-Oil-in-Water (W/O/W) Emulsion adjuvants (Coralvac RZ 528, Coralvac RZ 506, Coralvac AT 318, Coralvac AT 318 SIS and Coralvac 252) by Coral Biotechnology Industry and Trade Incorporated Company were demonstrated after intramuscular injection in mice. In both toxicity studies, no adverse reactions such as death, general appearance, behavior, or weight loss were observed in the mice in the experimental groups. The results indicate that clinical chemistry parameters demonstrated normal function of the major organs and no irreversible damage to the mice in all adjuvant groups compared to the control group. In histopathologic investigation of single dose toxicity study, inflammation, edema, and large amounts of lipid droplets were observed on the 7th day in all experimental groups. On the 14th day, when the control group and the experimental groups were compared, it was seen that inflammation and edema had decreased considerably. Similarly, repeated dose toxicity study showed mild inflammation and edema in the control group, while quite widespread and severe inflammation, edema, and diffuse lipid droplets of varying sizes were observed in all adjuvant groups compared to the control group. These observations would be useful for the future development of oil-based adjuvants and their use in veterinary inactive vaccines.