Mucosal immunization with a ricin toxin B subunit-rotavirus NSP4 fusion protein stimulates a Th1 lymphocyte response.
The castor-oil plant Ricinus communis A-B dimeric toxin B subunit (RTB) was genetically linked at its N-terminus with a 90 amino acid peptide from simian rotavirus SA-11 non-structural protein NSP4(90) and produced in Escherichia coli BL21 cells. Biologically active recombinant NSP4(90)-RTB fusion protein was shown to bind glycoprotein asialofetuin receptor molecules in an in vitro enzyme-linked immunosorbent assay (ELISA). Oral inoculation of the purified NSP4(90)-RTB ligand-antigen fusion protein delivered the chimeric protein to intestinal epidermal cells for mucosal immunization against rotavirus infection. Mice fed the NSP4(90)-RTB fusion protein generated higher humoral and intestinal antibody titers than mice inoculated with NSP4(90) alone. Titers of serum IgG2a antibodies were significantly higher than IgG1 titers suggesting a dominant Th1 lymphocyte immune response. ELISA measurement of cytokines secreted from splenocyte isolated from immunized mice confirmed NSP4(90)-RTB fusion protein stimulates a strong Th1 cell-mediated immune response. The experimental results demonstrate that the ricin toxin B subunit N-terminus can be used as a site for delivery of virus antigens to the gut associated lymphoid tissues for RTB-mediated immune stimulation of antiviral mucosal immune responses.
Choi
Nak-Won
NW
Center for Molecular Biology and Gene Therapy, Department of Biochemistry and Microbiology, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA.
Estes
Mary K
MK
Langridge
William H R
WH
D000284:Administration, Oral; D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D005260:Female; D006023:Glycoproteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D018928:Immunity, Mucosal / Q000276:immunology*; D007114:Immunization / Q000379:methods; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D012276:Ricin / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D012400:Rotavirus Infections / Q000276:immunology / Q000517:prevention & control; D022243:Rotavirus Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology*; D014118:Toxins, Biological / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D017361:Viral Nonstructural Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
D006023:Glycoproteins; C081369:NS28 protein, rotavirus; D011993:Recombinant Fusion Proteins; D022243:Rotavirus Vaccines; D014118:Toxins, Biological; D017361:Viral Nonstructural Proteins; D012276:Ricin