A non-toxic lectin for antigen delivery of plant-based mucosal vaccines

Vaccine. 2003 Feb 14;21(9-10):997-1005. doi: 10.1016/s0264-410x(02)00551-0.


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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adjuvants, Immunologic / administration & dosage*
  • Administration, Intranasal
  • Animals
  • Antibody Formation
  • Antigens / administration & dosage
  • Female
  • Green Fluorescent Proteins
  • Immunity, Mucosal
  • Luminescent Proteins / administration & dosage
  • Luminescent Proteins / genetics
  • Luminescent Proteins / immunology
  • Mice
  • Mice, Inbred ICR
  • Plants, Genetically Modified
  • Recombinant Proteins / administration & dosage
  • Recombinant Proteins / genetics
  • Recombinant Proteins / immunology
  • Ricin / administration & dosage*
  • Ricin / genetics
  • Tobacco / genetics
  • Vaccines / administration & dosage*


  • Adjuvants, Immunologic
  • Antigens
  • Luminescent Proteins
  • Recombinant Proteins
  • Vaccines
  • Green Fluorescent Proteins
  • Ricin