Oral vaccination with recombinant Lactobacillus plantarum encoding Trichinella spiralis inorganic pyrophosphatase elicited a protective immunity in BALB/c mice

Abstract

Background Trichinellosis is a serious zoonotic disease distributed around the world. It is needed to develop a safe, effective and feasible anti-Trichinella vaccine for prevention and control of trichinellosis. The aim of this study was to construct a recombinant Lactobacillus plantarum encoding Trichinella spiralis inorganic pyrophosphatase (TsPPase) and investigate its immune protective effects against T. spiralis infection. Methodology/Principal findings The growth of recombinant L. plantarum was not affected by TsPPase/pSIP409-pgsA′ plasmid, and the recombinant plasmid was inherited stably in bacteria. Western blot and immunofluorescence assay (IFA) indicated that the rTsPPase was expressed on the surface of recombinant L. plantarum. Oral vaccination with rTsPPase induced higher levels of specific serum IgG, IgG1, IgG2a and mucosal secretory IgA (sIgA) in BALB/c mice. ELISA analysis revealed that the levels of IFN-γ and IL-4 released from spleen, mesenteric lymph nodes and Peyer’s patches were evidently increased at 2–4 weeks following vaccination, compared to MRS (De Man, Rogosa, Sharpe) medium control group (P < 0.05). Immunization of mice with rTsPPase exhibited a 67.18, 54.78 and 51.91% reduction of intestinal infective larvae, adult worms and muscle larvae at 24 hours post infection (hpi), 6 days post infection (dpi) and 35 dpi, respectively (P < 0.05), and the larval molting and development was significantly inhibited by 45.45% at 24 hpi, compared to the MRS group. Conclusions TsPPase plays a crucial role in T. spiralis molting and development, oral vaccination with rTsPPase induced a significant local mucosal sIgA response and systemic Th1/Th2 immune response, and immune protection against T. spiralis infection in BALB/c mice.

Proteases secreted by Trichinella spiralis intestinal infective larvae damage the junctions of the intestinal epithelial cell monolayer and mediate larval invasion

“…The total volume of the mixture was 27.5 μL. All samples were denatured at 100 °C for 5 min, and 20 μL of each sample was analysed by SDS–PAGE analysis with 5% stacking gels and 12% resolving gels and Coomassie brilliant blue R-250 staining [ 50 ].…”

A novel C-type lectin from Trichinella spiralis mediates larval invasion of host intestinal epithelial cells

“…For determination of the ability of TsCTL to bind normal murine gut epithelium, small intestines from normal mice were fixed with paraformaldehyde, 3-μm intestinal tissue sections were prepared, and IFA was performed as described previously [ 56 ]. Briefly, after the sections were blocked using 5% goat serum, they were incubated with rTsCTL or IIL ESA (20 μg/mL) for 1 h at 37 ℃, and the subsequent procedures were the same as those used for IFA.…”

Characterization of a novel pyruvate kinase from Trichinella spiralis and its participation in sugar metabolism, larval molting and development

“…After washes with PBS, the worms and cross-sections were incubated with FITC-conjugated anti-mouse IgG (1:100; Abways, Shanghai, China). After washes again, they were observed under fluorescent microscopy (Olympus, Tokyo, Japan) [ 52 , 53 ].…”