Trichinellosis is a serious zoonotic
parasitic disease caused by Trichinella spiralis (T. spiralis) that causes considerable economic losses for the global pig breeding and food industries. As such, there is an urgent need for a
vaccine that can prevent T. spiralis
infection. Previous studies have reported that recombinant invasive Lactococcus lactis (LL) expressing Staphylococcus aureus
fibronectin binding protein A (LL-FnBPA+) can transfer
DNA vaccines directly to dendritic cells (DCs) across an epithelial cell monolayer, leading to significantly higher amounts of heterologous
protein expression compared to non-invasive Lactococcus lactis. In this study, the invasive bacterium Lactiplantibacillus plantarum (L. plantarum) expressing FnBPA was used as a carrier to deliver a novel oral
DNA vaccine consisting of T. spiralis adult putative
serine protease (Ts-ADpsp) and murine
interleukin (IL)-4
DNA to mouse intestinal epithelial cells. Experimental mice were orally immunized 3 times at 10-day intervals.
At 10 days after the last vaccination, mice were challenged with 350 T. spiralis infective larvae by oral inoculation. Immunization with invasive L. plantarum harboring pValac-Ts-ADpsp/pSIP409-FnBPA induced the production of anti-Ts-ADpsp-specific
IgG of serum, type 1 and 2 helper T cell
cytokines of mesenteric lymph node (MLN) and spleen, secreted (s)
IgA of intestinal lavage, and decreased T. spiralis burden and intestinal damage compared to immunization with non-invasive L. plantarum expressing Ts-ADpsp (pValac-Ts-ADpsp/pSIP409). Thus, invasive L. plantarum expressing FnBPA and
IL-4 stimulates both mucosal and cellular immune response to protect against T. spiralis
infection, highlighting its therapeutic potential as an effective
DNA vaccine for
trichinellosis.