Lycium barbarum polysaccharide promotes the immunoprotective effects of recombinant Lactobacillus plantarum vaccine expressing Trichinella spiralis cathepsin F-like protease 1 gene

Abstract

Trichinellosis caused by Trichinella spiralis (T. spiralis) is a zoonotic disease that seriously endangers human health. At present, vaccines that used to prevent trichinellosis was an effective way, but the production of antibody levels and immunogenicity is weakness. Adjuvants has been studied to elevate the antibody levels and immunogenicity of the vaccines. Therefore, it is urgent need to develop an effective adjuvant for the T. spiralis vaccine. The recent studies have indicated that traditional Chinese medicine polysaccharides as adjuvants can play a promote role in vaccine and it is a low-toxicity, and biodegradable compound. In this study, BALB/c mice were orally inoculated with recombinant Lactobacillus plantarum (L. plantarum) vaccine expressing T. spiralis cathepsin F-like protease 1 gene (rTs-CPF1), and it was administered thrice in the same dose at 10 days intervals. Meanwhile, Lycium barbarum polysaccharide (LBP) was orally administration until to 37 days. Mice were infected with 350 T. spiralis muscle larvae (ML) at 37 days after the first immunization. The results showed that LBP enhanced specific IgG and sIgA antibody levels against T. spiralis CPF1 protein in mice immunized with L. plantarum rTs-CPF1 + LBP group compared with L. plantarum rTs-CPF1 group. Moreover, LBP improved the expression levels of IFN-γ and IL-4, and the numbers of intestinal and intramuscular worm burden was significantly decreased in L. plantarum rTs-CPF1 + LBP group compared to L. plantarum rTs-CPF1 group. The reduction rate of adult worm and ML burden reached 47.31% and 68.88% in L. plantarum rTs-CPF1 + LBP group, respectively. In conclusion, LBP have a promoting role on the immunoprotective effects of T. spiralis vaccine and it may be considered as a novel adjuvant against parasitic vaccine.