Production of a new tetravalent vaccine targeting fimbriae and enterotoxin of enterotoxigenic Escherichia coli.

Abstract

Enterotoxigenic Escherichia coli (ETEC) is an important type of pathogenic bacteria that causes diarrhea in pigs. The objective of this study was to prepare a novel tetravalent vaccine to effectively prevent piglet diarrhea caused by E. coli. In order to realize the production of K88ac-K99-ST₁-LT_B tetravalent inactivated vaccine, the biological characteristics, stability, preservation conditions, and safety of the recombinant strain BL21(DE3) (pXKKSL4) were studied, and the vaccine efficacy and minimum immune dose were measured. The results indicated that the biological characteristics, target protein expression, and immunogenicity of the 1st to 10th generations of the strain were stable. Therefore, the basic seed generation was preliminarily set as the 1st to 10th generations. The results of the efficacy tests showed that the immune protection rate could reach 90% with 1 minimum lethal dose (MLD) virulent strain attack in mice. The immunogenicity was stable, and the minimum immune dose was 0.1 mL per mouse. Our research showed that the genetically engineered vaccine developed in this way could prevent piglet diarrhea caused by enterotoxigenic E. coli through adhesin and enterotoxin. In order to realize industrial production of the vaccine as soon as possible, we conducted immunological tests and production process research on the constructed K88ac-K99-ST₁-LT_B tetravalent inactivated vaccine. The results of this study provide scientific experimental data for the commercial production of vaccines and lay a solid foundation for their industrial production.