Protection against Trichinella spiralis in BALB/c mice via oral administration of recombinant Lactobacillus plantarum expressing murine interleukin-4.

• Constructed recombinant Lactobacillus plantarum NC8-pSIP409- pgsA -mIL-4. • Up-regulated Th2 immune response. • Improved antibody level against Trichinella spiralis. • Mice immunized with recombinant NC8-pSIP409- pgsA -mIL-4 showed reduces parasite loads in intestinal phase and muscular phase. Interleukin-4 (IL-4), an immunomodulatory cytokine derived from activated T lymphocytes were shown to regulate Th2-type immune responses. It plays an important role in anti-parasitic infections. In this study, a recombinant plasmid was designed using murine IL-4 co-expressed with pgsA anchor system of Lactobacillus plantarum NC8 and was delivered by live Lactobacillus plantarum NC8, which exhibited an enhanced immunogenicity in protection of BALB/c mice from infection with Trichinella spiralis. The results showed that the levels of serum IgG1 and mucosal secretory IgA (sIgA) were both increased significantly in mice orally inoculated with NC8-pSIP409- pgsA -mIL-4, and the Th2 phenotype immune response was up-regulated. A 29.9 % reduction in adult worm burden at 7 days post-infection (dpi) and 83.3 % reduction in muscle larvae burden at 28 dpi were observed in immune-stimulated mice with NC8-pSIP409- pgsA -mIL-4. Moreover, weight loss and pathological changes were also improved in mice of NC8-pSIP409- pgsA -mIL-4 group. Taken together, it suggests that NC8-pSIP409- pgsA -mIL-4 could improve the intestinal mucosal immunity and promoted the elimination of the adult worm in Trichinella -infected mice. This study laid the foundation for the development of a novel vaccines against Trichinellosis. [ABSTRACT FROM AUTHOR]