Intranasal Immunization with RecombinantAscaris suum14-Kilodalton Antigen Coupled with Cholera Toxin B Subunit Induces Protective Immunity toA. suumInfection in Mice

Abstract

Animals can be rendered immune to Ascaris parasites by immunization with infectious-stage larvae. The specific parasite gene products that mediate protective responses in ascariasis are unknown. We have identified a cDNA encoding Ascaris suum 14-kDa antigen (As14) and evaluated the vaccinal effect of the Escherichia coli-expressed recombinant protein (rAs14). GenBank analysis showed that As14 has low similarity at the amino acid level to a Caenorhabditis elegans gene product and to antigens of the filarial nematodes but not to other known proteins. In addition, As14 homologues were found to be expressed in human and dog roundworms. In mice that received intranasal administration of rAs14 coupled with cholera toxin B subunit (rAs14-CTB), there was a 64% reduction of recovery of larvae compared with that in the nontreated group. The vaccinated mice showed a significant increase in the total serum immunoglobulin G (IgG) levels and the mucosal IgA responses. Elevation of the rAs14-specific IgE response was also seen. Measurement of the IgG subclasses showed a higher level of IgG1 and a lower level of IgG2a antibody response in the sera of the immunized mice, suggesting that protection was associated with a type II immune response. As14 is the first protective antigen against A. suum infection to be identified. Our immunization trial results in laboratory animals suggest the possibility of developing a mucosal vaccine for parasitic diseases caused by ascarid nematodes.

Intranasal sensitization with Blomia Tropicalis antigens induces allergic responses in mice characterized by elevated antigen-specific and non-specific serum ige and peripheral blood eosinophil counts

“…The strong immunostimulating effect of CT is attractive for a new mucosal vaccine strategy in which CT is expected to be an effective adjuvant to deliver vaccine antigen to the mucosal immune system 11,16,28 . On the other hand, it has been indicated that immunization through mucosal tissue often induces an allergic response 11 .…”

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].…”

“…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.…”

Production of Ascaris suum As14 Protein and Its Fusion Protein with Cholera Toxin B Subunit in Rice Seeds

“…* from embryonated eggs. As14 is the 14-kDa protective surface antigen of A. suum, which is expressed throughout the entire larvae migration period in the host [23]. In the present study, genes encoding As14 and its fusion protein with a mucosal carrier, cholera toxin B subunit (CTB), were introduced into rice genome, and expressed in the seed endosperm under the control of the glutelin GluB-1 promoter.…”