Oral vaccination of mice with attenuated Salmonella encoding Trichinella spiralis calreticulin and serine protease 1.1 confers protective immunity in BALB/c mice

Abstract

Background Trichinella spiralis is a foodborne parasitic nematode which is a serious risk to meat safety. Development of anti-Trichinella vaccine is needed to control Trichinella infection in food ani-mals. In this study, two novel T. spiralis genes (calreticulin and serine protease 1.1) in combination were used to construct oral DNA vaccines, and their induced protective immunity was evaluated in a murine model. Methodology/Principal findings TsCRT+TsSP1.1, TsCRT and TsSP1.1 DNA were transformed into attenuated Salmonella typhimurium ΔcyaSL1344. Oral vaccination of mice with TsCRT+TsSP1.1, TsCRT and TsSP1.1 DNA vaccines elicited a gut local mucosal sIgA response and systemic Th1/Th2 mixed response. Oral vaccination with TsCRT+TsSP1.1 induced obviously higher level of serum specific antibodies, mucosal sIgA and cellular immune response than either of single TsCRT or TsSP1.1 DNA vaccination. Oral vaccination of mice with TsCRT+TsSP1.1 exhib-ited a 53.4% reduction of enteral adult worms and a 46.05% reduction of muscle larvae, con-ferred a higher immune protection than either of individual TsCRT (44.28 and 42.46%) or TsSP1.1 DNA vaccine (35.43 and 29.29%) alone. Oral vaccination with TsCRT+TsSP1.1, TsCRT and TsSP1.1 also obviously ameliorated inflammation of intestinal mucosa and skel-etal muscles of vaccinated mice after challenge. Conclusions TsCRT and TsSP1.1 might be regarded the novel potential targets for anti-Trichinella vac-cines. Attenuated Salmonella-delivered DNA vaccine provided a prospective approach to control T. spiralis infection in food animals.