Partially Protective Immunity Induced by a 20 kDa Protein Secreted by Trichinella spiralis Stichocytes

Abstract

Background Trichinella spiralis infection induces protective immunity against re-infection in animal models. Identification of the antigens eliciting acquired immunity during infection is important for vaccine development against Trichinella infection and immunodiagnosis.Methods and FindingsThe T. spiralis adult cDNA library was immunoscreened with sera from pigs experimentally infected with 20,000 infective T. spiralis larvae. Total 43 positive clones encoding for 28 proteins were identified; one of the immunodominant proteins was 20 kDa Ts-ES-1 secreted by Trichinella stichocytes and existing in the excretory/secretory (ES) products of T. spiralis adult and muscle larval worms. Ts-ES-1 contains 172 amino acids with a typical signal peptide in the first 20 amino acids. The expression of Ts-ES-1 was detected in both the adult and muscle larval stages at the mRNA and protein expression levels. Mice immunized with recombinant Ts-ES-1 (rTs-ES-1) formulated with ISA50v2 adjuvant exhibited a significant worm reduction in both the adult worm (27%) and muscle larvae burden (42.1%) after a challenge with T. spiralis compared to the adjuvant control group (p<0.01). The rTs-ES-1-induced protection was associated with a high level of specific anti-Ts-ES-1 IgG antibodies and a Th1/Th2 mixed immune response.ConclusionThe newly identified rTs-ES-1 is an immunodominant protein secreted by Trichinella stichocytes during natural infection and enables to the induction of partial protective immunity in vaccinated mice against Trichinella infection. Therefore, rTs-ES-1 is a potential candidate for vaccine development against trichinellosis.

Vaccination with a Paramyosin-Based Multi-Epitope Vaccine Elicits Significant Protective Immunity against Trichinella spiralis Infection in Mice

“…Firstly, a combination of T- and B-cell epitopes may enhance the induction of both cell-mediated and humoral immune responses. It has been proved that a mixed humoral and cellular immune response contributed to the protective immunity against T. spiralis infection ( Bi et al, 2015 ; Liu et al, 2015 ). Secondly, the strategy involves positioning T cell epitopes on the N-terminal side and B-cell epitopes on the C-terminal side separated each epitope by a di-lysine linker.…”

“…During the past decades, many vaccine candidates against Trichinellosis have been investigated and reported, including those based on crude larval extracts ( Deville et al, 2005 ), excretory-secretory (ES) products ( Dea-Ayuela et al, 2006 ), DNA ( Wang et al, 2016 ), recombinant proteins ( Bi et al, 2015 ), peptides ( Castillo et al, 2013 ) or combined DNA with protein ( Gu et al, 2014 ), all of them induced different extents of partial protective immunity in animal models. However, due to the complexity of the life cycle, diversity of stage-specific antigens and immune-evasion strategies of T. spiralis ( Zhang et al, 2011 ; Sun et al, 2015 ), researchers face the challenges in developing effective vaccines against Trichinellosis.…”

Vaccines againstTrichinella spiralis: Progress, challenges and future prospects

“…Here, we mainly review the protective immunity against T. spiralis infection elicited from the crude mixed ES products and those uncharacterized components with a certain size in ES products (Table ). By now, the crude ES antigens at the certain molecular size of 20 kDa, 43 kDa, 53 kDa, 48 kDa, 49 kDa and 50/55 kDa have been investigated as immunogens against T. spiralis infection (Bi et al., ; Lightowlers & Rickard, ; Nagano, Wu, & Takahashi, ; Robinson, Bellaby, Chan, & Wakelin, ). All of them showed effective immune efficacies in reduction in the worm burden.…”

Vaccination against Trichinella spiralis: Potential, Limitations and Future Directions

“…The surface protein 28.9 kDa (Ts14-3-3) [34], the E/S protein of 35.5 kDa (TspSP1.2) [35], 54.7 kDa amino peptidase (TsAP) also expressed by adult worms and NBL, located primarily at the cuticle and internal organs of the parasite [36], the protein of 20 kDa (Ts-ES-1) existing in the E/S products of T. spiralis adult and ML [37], and paramyosin (Ts-Pmy) [38] among others have been tested in mice. In all cases, partial protection assessed against the enteral and muscle phase of the infection was elicited (35-55%).…”