Molecular characterization of a putative serine protease from Trichinella spiralis and its elicited immune protection

Abstract

In our previous work, a Trichinella spiralis putative serine protease (TsSP) was identified from ES products of T. spiralis intestinal infective larvae (IIL) and adult worms (AW) by immunoproteomics: it was highly expressed in IIL compared with muscle larvae (ML). In this study, the TsSP biological characteristics in larval invasion and growth were identified and its potential as a vaccine target against Trichinella infection were investigated. Expression of TsSP at various developmental phases (newborn larvae, ML, IIL, and AW) was detected by qPCR, immunofluorescent test and Western blotting. The rTsSP could specifically bind to the intestinal epithelial cell (IEC) membrane and enter into the cytoplasm. Anti-rTsSP serum suppressed the larval invasion of enterocytes in a dose-dependent mode, and killed newborn and ML of T. spiralis, decreased larval infectivity and development in the host by an ADCC-mediated mechanism. Immunization of mice with rTsSP produced a Th2 predominant immune response, and resulted in a 52.70% reduction of adult worms at 5 days post-infection (dpi) and a 52.10% reduction of muscle larvae at 42 dpi. The results revealed there was an interaction between TsSP and the host’s IEC; TsSP might be a pivotal protein for the invading, growing and parasiting of this nematode in the host. Vaccination of mice with rTsSP elicited immune protection, and TsSP is a potential target molecule for vaccines against enteral Trichinella infection.

Protective immunity against Trichinella spiralis in mice elicited by oral vaccination with attenuated Salmonella-delivered TsSP1.2 DNA

“…The high levels of TsSP1.2-specific IgG and sIgA produced by oral vaccination with rTsSP1.2 might inhibit larval invasion and development, and reduce female fecundity [ 57 , 59 , 62 ]. Furthermore, anti-TsSP1.2 antibodies might take part in the killing of newborn larvae by an ADCC-mediated mechanism [ 63 ]. Therefore, oral vaccination with TsSP1.2 DNA vaccine produced a significant reduction of muscle larva burden in immunized mice.…”

Characterization of a serine protease inhibitor from Trichinella spiralis and its participation in larval invasion of host’s intestinal epithelial cells

“…Previous studies demonstrated that ADCC-mediated destruction of T. spiralis NBL was dependent on specific anti- Trichinella IgG [ 62 , 63 ]. Cytotoxicity against NBL in the lungs of T. spiralis- infected mice was found to be IgE-mediated by Falduto et al [ 64 ].…”

Molecular characterization of a Trichinella spiralis elastase-1 and its potential as a diagnostic antigen for trichinellosis

“…Somatic soluble proteins of T. spiralis different life stages and rTsEla were separated on SDS-PAGE, and transferred onto nitrocellulose membranes (Merck Millipore, Billerica, MA, USA) at 18 V for 35 min [48]. The membrane was cut into strips, and blocked using 5% skimmed milk at 37 °C for 2 h. After washing with TBS-0.5% Tween 20 (TBST), the strips were probed with anti-rTsEla serum (1:100) for 2 h at 37 °C, followed by incubation with HRPanti-mouse IgG conjugate (1:5000; Southern Biotech, Tuscaloosa, AL, USA) at 37 °C for 1 h. Following washing again, the strips were developed using 3,3′-diaminobenzidine tetrahydrochloride (DAB; Sigma-Aldrich, St. Louis, MO, USA) [31,49].…”