Development and effect evaluation of a vaccine culture medium with high antigenic activity for the prevention of porcine edema disease caused by Escherichia coli based on response surface methodology

Abstract:

[Background] Porcine edema disease caused by Escherichia coli is a major disease attacking pigs. The existing culture medium used for vaccine preparation has a low cell density.[Objective] To develop a vaccine culture medium with high antigenic activity for the prevention of porcine edema disease. [Methods] A commercially available vaccine culture medium against porcine edema disease was used as the control. The response surface methodology was employed to optimize the composition of the culture medium through single-factor experiments, Plackett-Burman (PB) design, and Box-Behnken (BB) design. The optimized culture medium was used to culture the E. coli eliciting porcine edema disease, and the antigenic activity of the culture at different time points was evaluated. In addition, the inactivated vaccine was prepared and used for animal immunization. [Results] The expanded culture of the pathogen in the developed culture medium showed that the viable cell count of the strain reached more than 5×10⁹ CFU/mL, approximately twice that of the control group. Meanwhile, the titer of the inactivated vaccine reached 1:140 000, and the antigen protein titer peaked at the time point of 9 h. [Conclusion] The developed vaccine culture medium significantly improved the cell density and antigenic activity of E. coli causing porcine edema disease, providing technical guidance for preparing inactivated vaccines against porcine edema disease.