Vaccination of mice with an antigenic serine protease-like protein elicits a protective immune response against Trichinella spiralis infection.

Trichinellosis has major economic impacts on animal husbandry and food safety, and the control and elimination of trichinellosis is a major objective of veterinary medicine. A gene encoding serine protease of Trichinella spiralis (Ts-Adsp) was identified by immunoscreening an adult T. spiralis cDNA library. In this study, the recombinant Ts-Adsp protein (rTs-Adsp) was cloned and expressed in a prokaryotic expression system and purified by Ni-affinity chromatography. To determine whether the purified rTs-Adsp is a potential vaccine candidate for the control of T. spiralis infection, we immunized BALB/c mice with this protein in combination with an alum adjuvant and subsequently challenged with T. spiralis larvae. The results showed that mice vaccinated with rTs-Adsp exhibited an average reduction in the muscle larvae burden of 46.5% relative to the control group. Immunization with the rTs-Adsp antigen induced both humoral and cellular immune responses, which manifested as elevated specific anti-rTs-Adsp IgG and IgE antibodies and a mixed Th1-Th2 response, as determined by Th1 (IFN-γ and IL-2) and Th2 (IL-4, IL-10, and IL-13) cytokine profiling, with the Th2 predominant. Thus, purified rTs-Adsp is able to limit the invasion of T. spiralis , and this protein could be an effective vaccine candidate for trichinellosis.