ABSTRACT
We have recently communicated the oral and parental immunogenicity of the structural protein VP1 of foot and mouth disease virus (FMDV) expressed in different transgenic plants. Those results clearly indicated the necessity of increasing the expression of the foreign genes in the transgenic plant to avoid additional steps toward the purification and/or concentration of the antigen of interest. Here, we report the production of transgenic potatoes plants containing the VP1 gene cloned under the regulatory activity of either a single (pRok2) or a double (pRok3) copy of the S35 cauliflower mosaic virus (CaMV 35S) promoter, as a strategy for increasing the level of VP1 gene expression. The presence of the VP1 gene in the plants was confirmed by polymerase chain reaction (PCR) and its specific transcription activity was demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR). The results showed that, although the immunized animals presented a FMDV VP1 specific antibody response and protection against the experimental challenge, no significant differences were demonstrated in the immunizing activity of plant extracts obtained from the pRok2 or pRok3 transformed plants. These results confirm those previously obtained using other plant species allowing the possibility of using plants as antigen expression vectors, and demonstrated that at least in the potato system, the use of double CaMV 35S promoter does not cause a significant increase in the level of the VP1 expressed.
Subject(s)
Antibodies, Viral/blood , Aphthovirus/immunology , Capsid/immunology , Foot-and-Mouth Disease/immunology , Plants, Genetically Modified/immunology , Solanum tuberosum/immunology , Animals , Capsid/genetics , Capsid/metabolism , Capsid Proteins , Foot-and-Mouth Disease/prevention & control , Genes, Viral , Immunization , Male , Mice , Mice, Inbred BALB C , Plants, Genetically Modified/genetics , Plants, Genetically Modified/metabolism , Recombinant Proteins/immunology , Solanum tuberosum/genetics , Solanum tuberosum/metabolism , Transformation, Genetic , Viral VaccinesABSTRACT
Transgenic plants represent an inexpensive alternative to classical fermentation systems for production of recombinant subunit vaccines. Transgenic potato plants were created that express the N-terminal domain of the glycoprotein S (N-gS) from Transmissible gastroenteritis coronavirus (TGEV), containing the major antigenic sites of the protein. Extracts from potato tubers expressing N-gS were inoculated intraperitoneally to mice, and the vaccinated mice developed serum IgG specific for TGEV. Furthermore, when potato tubers expressing N-gS were fed directly to mice, they developed serum antibodies specific for gS protein, demonstrating the oral immunogenicity of the plant derived spike protein from TGEV.
Subject(s)
Coronavirus/immunology , Membrane Glycoproteins/immunology , Solanum tuberosum , Viral Envelope Proteins/immunology , Administration, Oral , Animals , Antibodies, Viral/blood , Antigens, Viral/administration & dosage , Coronavirus/chemistry , Coronavirus/genetics , Coronavirus Infections/prevention & control , Enzyme-Linked Immunosorbent Assay , Membrane Glycoproteins/genetics , Mice , Mice, Inbred BALB C , Plant Proteins/genetics , Plants, Genetically Modified , Plasmids , Polymerase Chain Reaction , Recombinant Proteins/administration & dosage , Spike Glycoprotein, Coronavirus , Transformation, Genetic , Vaccines, Synthetic/administration & dosage , Viral Envelope Proteins/genetics , Viral Vaccines/administration & dosageABSTRACT
The major structural protein VP60 of rabbit hemorrhagic disease virus (RHDV) has been produced in transgenic potato plants under the control of a cauliflower mosaic virus 35S promoter or a modified 35S promoter that included two copies of a strong transcriptional enhancer. Both types of promoters allowed the production of specific mRNAs and detectable levels of recombinant VP60, which were higher for the constructs carrying the modified 35S promoter. Rabbits immunized with leaf extracts from plants carrying this modified 35S promoter showed high anti-VP60 antibody titers and were fully protected against the hemorrhagic disease.