Content area
Full Text
(ProQuest: ... denotes formulae and/or non-US-ASCII text omitted; see image)
[dagger]. These authors contributed equally to this work.
INTRODUCTION
Trichinella spp. are intestinal nematode parasites that can cause trichinellosis in humans and animals (Dupouy-Camet, 2000). More than 100 species of mammals, birds and reptiles can be infected by T. spiralis (Pozio and Zarlenga, 2013); domestic pigs, horses, dogs and cats are known as the most important hosts of T. spiralis. Infection occurs when humans consume raw or undercooked meat of different animal origins containing T. spiralis muscle larvae (ML). Trichinellosis is a public health hazard, and it also an economic problem in animal production and food safety (Dorny et al. 2009). It is difficult to control this zoonosis due to its wide distribution of domestic and wild animal reservoirs (Wang and Cui, 2001; Wang et al. 2006; Cui et al. 2011; Murrell and Pozio, 2011). So far, useful and stable anti-Trichinella vaccines that can be used in animal husbandry have not been developed yet. Therefore, it is necessary to develop a vaccine to prevent Trichinella infection in domestic animals and humans.
Trichinella spiralis is a nematode parasite that spends its larval and adult life stages in the same host. It has three major antigenic stages, ML, adult worms (AD) and new-born larvae (NBL). During natural course of T. spiralis infection, AD get pregnant and NBL are released in the intestines of the host, then all the AD evacuate from the host through intestines between 10 and 15 days post-infection (dpi). The NBL arrive at striated muscle through lymphatic vessels and blood circulation, and then develop into encapsulated ML in 20 days. Then ML start long-term parasitizing in striated muscle (Pozio, 1989; Gottstein et al. 2009). NBL is a key stage for the growth of T. spiralis, without the protection of capsule, larvae will be exposed to muscle immune system. Therefore, it is necessary to think highly of antigens from the NBL stage.
A highly antigenic NBL stage-specific serine protease gene, Ts-NBLsp, was obtained via a subtractive cDNA library of T. spiralis NBL (Liu et al. 2007). Ts-NBLsp showed encouraging potential in the early detection of Trichinella infection, but the function of it in vivo is unclear. Multiple serine proteases have been...