Abstract
BackgroundGiardia lamblia is one of the most common infectious protozoans in human that may cause diarrhea in travelers. Searching for antigens that induced effectively protective immunity has become a key point in the development of vaccine against giardiasis.Methodology/Principal FindingsMice vaccinated with G. lamblia trophozozite-specific α1-giardin DNA vaccine delivered orally by attenuated Salmonella typhimurium SL7027 elicited 74.2% trophozoite reduction, but only 28% reduction in cyst shedding compared with PBS buffer control. Oral vaccination with Salmonella-delivered cyst-specific CWP2 DNA produced 89% reduction in cysts shedding in feces of vaccinated mice. Significantly, the mice vaccinated with Salmonella-delivered bivalent α1-giardin and CWP2 DNA vaccines produced significant reduction in both trophozoite (79%) and cyst (93%) in feces of vaccinated mice. This parasite reduction is associated with the strong local mucosal IgA secretion and the IgG2a-dominant systemic immune responses in vaccinated mice.ConclusionsThe results demonstrate that bivalent vaccines targeting α1-giardin and CWP2 can protect mice against the colonization of Giardia trophozoite and block the transformation of cyst in host at the same time, and can be used to prevent Giardia infection and block the transmission of giardiasis.
Highlights
Giardia lamblia is a protozoan parasite that cause diarrhea in travelers[1].The prevalence of giardiasis has been reported to be as high as 20–40% in developing countries [2]
The results demonstrate that bivalent vaccines targeting α1-giardin and cyst wall protein-2 (CWP2) can protect mice against the colonization of Giardia trophozoite and block the transformation of cyst in host at the same time, and can be used to prevent Giardia infection and block the transmission of giardiasis
The rabbit antisera were made by immunizing each two female New Zealand white rabbits with age of 6 months provided by the Animal facility at Jilin University, each hosted in a cage with 60 x 60 x 40 cm, with 200 ug of rCWP-S or rα1-giardin formulated with Freud’s complete adjuvant (FCA) and boosted 3 weeks after with the same amount of proteins formulated with Freud’s incomplete adjuvant (FIA)
Summary
Giardia lamblia is a protozoan parasite that cause diarrhea in travelers[1].The prevalence of giardiasis has been reported to be as high as 20–40% in developing countries [2]. Bivalent Vaccines against Giardia lamblia Infection infected by the ingestion of cysts in contaminated water or food. Since ingestion of as few as ten cysts can cause infection [3]. In small intestine, ingested cyst releases trophozoite that causes giardiasis with symptoms of diarrhea, abdominal pain, malabsorption and weight loss. Trophozoites are transformed into cysts in the gut lumen. Cysts contain the hard cyst wall which enables to resist the harsh environmental conditions when the cysts are passed out in the feces [4]. Editor: Victor C Huber, University of South Dakota, UNITED STATES
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