Vaccination of mice with a recombinant novel cathepsin B inhibits Trichinella spiralis development, reduces the fecundity and worm burden

Abstract

BackgroundTrichinella spiralis is a major zoonotic tissue-dwelling nematode, which is a public health concern and a serious hazard to animal food safety. It is necessary to exploit an anti-Trichinella vaccine to interrupt the transmission of Trichinella infection among animals and from animals to humans. The purpose of the present study was to characterize the novel T. spiralis cathepsin B (TsCB) and to evaluate the immune protection elicited by immunization with recombinant TsCB (rTsCB).MethodsThe complete cDNA sequences of the TsCB gene were cloned, expressed and purified. The antigenicity of rTsCB was investigated by western blot analysis and ELISA. Transcription and expression of TsCB at various T. spiralis life-cycle stages were analyzed by RT-PCR and indirect immunofluorescent assay (IIFA). The mice were subcutaneously immunized with rTsCB, and serum level of TsCB-specific IgG (IgG1 and IgG2a) and IgE antibodies were assayed by ELISA. Immune protection elicited by vaccination with rTsCB was investigated.ResultsThe TsCB was transcribed and expressed in four T. spiralis life-cycle stages (adult worm, AW; newborn larvae, NBL; muscle larvae, ML; and intestinal infective L1 larvae), it was primarily located in the cuticle and stichosome of the parasitic nematode. Vaccination of mice with rTsCB produced a prominent antibody response (high level of specific IgG and IgE) and immune protection, as demonstrated by a 52.81% AW burden reduction of intestines at six days post-infection (dpi) and a 50.90% ML burden reduction of muscles at 35 dpi after oral larva challenge. The TsCB-specific antibody response elicited by immunization with rTsCB also impeded intestinal worm growth and decreased the female fecundity.ConclusionsTsCB might be considered as a novel potential molecular target to develop vaccines against T. spiralis infection.

Protective immunity in mice vaccinated with a novel elastase-1 significantly decreases Trichinella spiralis fecundity and infection

“…In recent years, some protein molecules from various T. spiralis lifecycle stages have been characterized and expressed, and their immune protection was also evaluated, such as paramyosin (Ts-Pmy) from an adult cDNA library [9], TspGST and fructose-1,6-bisphosphate aldolase (Ts-FBPA) from the T. spiralis draft genome with high expression at the ML stage [33,68], Ts31 from the ML ES proteins [54], serine protease (TsSP) from IIL and ML surface proteins [55], and cathepsin B (TsCB) from the T. spiralis draft genome [56]. However, when these recombinant proteins were used for vaccinating mice, they exhibited only 36.2-53.50% ML reduction following T. spiralis challenge.…”

“…The AWs were recovered from the small intestines of ten mice of each group at 7 dpi [54,55]. The ML were collected from an additional ten mice at 42 dpi by digesting the infected mouse striated muscles [56]. Moreover, the length of adult females was measured by microscopy.…”

Vaccination of Mice with a Novel Trypsin from Trichinella spiralis Elicits the Immune Protection against Larval Challenge

“…To assess the cytotoxic activity of anti-TsT immune serum, the ADCC test was conducted in this study. The results showed that anti-rTsT immune serum promoted the adhering and killing of the PECs to the NBL, and the cytotoxic activity was dose-dependent of anti-rTsT antibodies, suggesting that anti-TsT IgG participated in the killing and destruction of newborn larvae by the ADCC fashion [ 56 , 64 ]. The sera used in this study were not heat-inactivated to inactivate complement.…”

“…Furthermore, the ML, IIL and AW were embedded in paraffin, 3-µm thick cross-sections were prepared using a microtome. Expression and tissue localization of native TsT in various T. spiralis stages were determine with IIFT [ 16 , 56 ]. In brief, the whole worms and worm cross-sections were blocked using 1% BSA in PBS and then incubated with various sera (1:10; anti-rTsT serum, infection serum or pre-immune serum) at 37 °C for 2 h. Following washes with PBS, worms and cross-sections were stained with anti-mouse IgG conjugated FITC (1:100; Santa Cruz Biotech, Dallas, Texas, USA).…”

Molecular characterization of a Trichinella spiralis serine proteinase

“…Moreover, the worms were embedded in paraffin, and 3-µm-thick cross-sections were cut with a microtome. The expression and worm tissue location of native TsSerp in diverse T. spiralis stages were observed using IFA as previously reported [46,47]. Briefly, intact whole nematodes and cross-sections were blocked with 5% normal goat serum in PBS and then probed at 37 °C for 2 h with 1:10 dilutions of various sera (anti-rTsSerp serum, infection serum or pre-immune serum).…”