title: A non-toxic lectin for antigen delivery of plant-based mucosal vaccines.
abstract: RicinB, the non-toxic galactose/N-acetylgalactosamine-binding subunit of ricin, was fused to a model antigen, green fluorescent protein (GFP), and expressed in tobacco plants and hairy root cultures to test for utility in mucosal vaccine delivery/adjuvancy. The fusion protein retained both GFP fluorescence and galactose/galactosamine-binding activity. Intranasal immunization of mice with galactosamine-affinity purified ricinB:GFP recovered from tobacco root cultures triggered significant increases in GFP-specific serum IgGs. This strong humoral response was comparable to that observed following GFP immunization with cholera toxin adjuvant. GFP at the same concentrations but without an adjuvant was non-immunogenic. Induction of higher levels of IgG(1) than IgG(2a) following ricinB:GFP immunization suggested the presence of a Th2 response. Serum and fecal anti-GFP IgA were also induced by immunization with ricinB:GFP. Our data suggest that ricinB can be used as an adjuvant and antigen carrier to the mucosa and is efficient in eliciting systemic and mucosal immune responses.
authors.affiliation: Fralin Biotechnology Center, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA 24061-0346, USA.
authors.forename: Fabricio
authors.initials: F
authors.lastname: Medina-Bolivar
authors.forename: Rhonda
authors.initials: R
authors.lastname: Wright
authors.forename: Vanessa
authors.initials: V
authors.lastname: Funk
authors.forename: Danielle
authors.initials: D
authors.lastname: Sentz
authors.forename: Lisa
authors.initials: L
authors.lastname: Barroso
authors.forename: Tracy D
authors.initials: TD
authors.lastname: Wilkins
authors.forename: William
authors.initials: W
authors.lastname: Petri
authors.forename: Carole L
authors.initials: CL
authors.lastname: Cramer
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000281:Administration, Intranasal; D000818:Animals; D000917:Antibody Formation; D000941:Antigens / Q000008:administration & dosage; D005260:Female; D049452:Green Fluorescent Proteins; D018928:Immunity, Mucosal; D008164:Luminescent Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D051379:Mice; D008813:Mice, Inbred ICR; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D012276:Ricin / Q000008:administration & dosage* / Q000235:genetics; D014026:Nicotiana / Q000235:genetics; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D000276:Adjuvants, Immunologic; D000941:Antigens; D008164:Luminescent Proteins; D011994:Recombinant Proteins; D014612:Vaccines; D049452:Green Fluorescent Proteins; D012276:Ricin