RecombinantAscaris16‐Kilodalton Protein–Induced Protection againstAscaris suumLarval Migration after Intranasal Vaccination in Pigs

Abstract

We recently cloned a protective antigen that is commonly expressed in Ascaris species that infect humans and pigs. We evaluated the vaccinal effects of this 16-kilodalton protein (As16) in pigs, the natural host of Ascaris suum, by intranasal immunization. Pigs that received Escherichia coli-expressed recombinant As16 (rAs16) coupled with cholera toxin (CT) had significantly elevated levels of rAs16-specific serum immunoglobulin G (IgG) and mucosal-associated IgA antibodies. rAs16 evoked a type II immune response characterized by elevated levels of interleukin-4 and -10 in the culture supernatants of 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 migration of A. suum larvae through the lungs, as indicated by a 58% reduction in the recovery of lung-stage third-stage larvae (L3), compared with that in nonvaccinated controls. Purified immunoglobulin from rAs16-CT-vaccinated pigs inhibited survival of infective L3 and interrupted the molting of lung-stage L3. Immunofluorescence studies revealed that this immunoglobulin bound to the digestive tracts of L3, suggesting that it might inactivate functions of the gut tissues of Ascaris species. We conclude that rAs16 is a promising mucosal vaccine candidate for pig and human ascariasis.

Intranasal Immunization of Lambs with Serine/Threonine Phosphatase 2A against Gastrointestinal Nematodes

“…Intranasal immunization has been used before both in laboratory mouse models (24,50,51) and in domestic animal species (52), while bacterial components have also been used successfully in immunization (21,22,53,54), but the combination of these methods for nematode vaccination has not been tested except in a recent experiment using the same protein, PP2Ar, against A. costaricensis (20) in mice. Immunization provoked lower parasite burdens and increased levels of interleukin-17 (IL-17) and specific IgA.…”

Protection of Mice from Rabies by Intranasal Immunization with Inactivated Rabies Virus

“…Furthermore, when whole virus particles were used as antigens in the present study, even without cT adjuvant, antibody responses and VNA production were detected in intranasally immunized mice (Tables 1 and 2). when using recombinant protein as an antigen, it is rare to detect antibody production in intranasal immunization without cT or other adjuvants [2,1,30,28]. Thus, the successful induction of anti-viral immunity demonstrated in our study by administration of crV without cT may largely be attributed to the use of entire viral particles as immunogen.…”

“…it is easier to vaccinate animals with the mucosal method than the parenteral method, and unlike parenteral vaccines, mucosal vaccination stimulates sigA production in mucosal tissues, which could effectively inhibit the entry of pathogens that invade their hosts via the mucosal route. The efficacy of mucosal immunization has been well documented for mucosal pathogens, such as influenza virus, Newcastle disease virus, foot and mouth disease virus, Aujeszky's disease virus, hiV and Ascaris suum [15,19,22,25,26,28,29,30]. Furthermore, mucosal immunization can also stimulate systemic immune responses, such as serum igG production and cytokine production by T cells [28,29].…”

“…The efficacy of mucosal immunization has been well documented for mucosal pathogens, such as influenza virus, Newcastle disease virus, foot and mouth disease virus, Aujeszky's disease virus, hiV and Ascaris suum [15,19,22,25,26,28,29,30]. Furthermore, mucosal immunization can also stimulate systemic immune responses, such as serum igG production and cytokine production by T cells [28,29]. Thus, mucosal vaccination can also be used for non-mucosal, penetrative pathogens, such as Plasmodium parasites, Clostridium tetanus and Leishmania major [1,2,16,23].…”

“…recently, mucosal immunization using recombinant proteins or inactivated pathogens has been studied for both mucosal [15,19,22,25,26,28,29,30] and nonmucosal pathogens [1,2,16,23]. Due to the ease of administration and the efficacy against both mucosal and non-mucosal pathogens, a mucosal immunization strategy with recombinant protein is considered as one of the most promising alternative vaccination methods.…”