Evaluation of the immune effects of three immunopotentiators on pseudorabies virus inactivated vaccine

Objective  To evaluate the immunopotentiation effects of levamisole hydrochloride (LH), concanavalin A (ConA) and muramyl dipeptide (MDP) on pseudorabies virus (PRV) inactivated vaccine.

Method  The immunopotentiators were mixed into inactivated PRV virus aqueous phase, and emulsified with oil phase to make inactivated vaccines containing immunopotentiators. The final concentrations of immunopotentiators were LH 7.5 mg·mL^–1, ConA 25.0 mg·mL^–1 and MDP 150.0 mg·mL^–1 respectively. The second immunization was on the 14th day after the first immunization. Mouse serum samples were collected on the 14th day after the first immunization, 7th and 14th day after the second immunization to detect relative cytokines (IL-2, IL-4, IFN-γ) and specific antibody levels. On the 14th day after the second immunization, all mice were attacked and the final attack protective rate was calculated.

Result  Compared to Baiyou group, ConA and MDP groups extremely significantly improved IL-2 content in mouse serum on the 14th day after the second immunization. LH group significantly improved IL-4 content on the 14th day after the first immunization, and MDP group significantly improved IL-4 content on the 14th day after the second immunization. The three immunopotentiators extremely significantly enhanced IFN-γ contents and specific antibody levels on the 14th and 7th day after the second immunization respectively, and also improved the attack protective rates. The survival rates of LH and ConA groups were 20%, while that of MDP group was 60%.

Conclusion  Three immunopotentiators within the range of the experimental dosages can enhance the immune effects of PRV inactivated vaccine in varying degrees.