We evaluated the vaccinal effects of As16 in pigs, the natural host of A. suum, using the intranasal route of immunization. Pigs that received E. coli-expressed recombinant As16 coupled with cholera toxin (rAs16-CT) had significantly elevated levels of rAs16-specific serum IgG and mucosal-associated IgA antibodies. The recombinant protein evoked a type II immune response characterized by elevated levels of IL-4 and IL-10 in the culture supernatants of the peripheral blood mononuclear cells of the vaccinated pigs. An increased level of rAs16-specific serum IgG1 was also detected. Pigs vaccinated with rAs16-CT were protected from challenged A. suum larval migration through the lungs, as indicated by a 58% reduction in the recovery of lung-stage L3 compared with that in the non-vaccinated controls. Purified-Ig from rAs16-CT-vaccinated pigs inhibited the survival of infective L3, and interrupted the molting of lung-stage L3. We conclude that rAs16 is a promising mucosal vaccine candidate for pig ascariasis.
(Parasitic Disease Section, Department of Infectious Diseases TEL +81-29-838-7751)
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