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Abstract

Although edible vaccines seem to be feasible, antigens of human pathogens have mostly been expressed in plants that are not attractive for human consumption (such as potatoes) unless they are cooked. Boiling may reduce the immunogenicity of many antigens. More recently, the technology to transform fruit and vegetable plants have become perfected. We transformed carrot plants with Agrobacterium tumefaciens to generate plants (which can be eaten raw) transgenic for an immunodominant antigen of the measles virus, a major pathogen in man. The hemagglutinin (H) glycoprotein is the principle target of neutralizing and protective antibodies against measles. Copy numbers of the H transgene were verified by Southern blot and specific transcription was confirmed by RT-PCR. The H protein was detected by western blot in the membrane fraction of transformed carrot plants. The recombinant protein seemed to have a 8% lower molecular weight than the viral protein. Although this suggests a different glycosylation pattern, proper folding of the transgenic protein was confirmed by conformational-dependent monoclonal antibodies. Immunization of mice with leaf or root extracts induced high titres of IgG1 and IgG2a antibodies that cross-reacted strongly with the measles virus and neutralized the virus in vitro. These results demonstrate that transgenic carrot plants can be used as an efficient expression system to produce highly immunogenic viral antigens. Our study may pave the way towards an edible vaccine against measles which could be complementary to the current live-attenuated vaccine.

Expression of rabies virus G protein in carrots (Daucus carota)

“…A possible explanation for this is a difference in the proteolytic pattern (Faye et al 2005). However, there are several reports in which this modification does not affect their immunological properties (Marquet-Blouin et al 2003;Streatfield et al 2003;Tae-Jin et al 2003;Yusibov et al 1997).…”

“…To date, most of the antigen expression systems have employed non-edible plants (tobacco and Arabidopsis) (Modelska et al 1998;Marquet-Blouin et al 2003). Heating may inactivate antigens, and the use of plants that can be eaten without heating would permit antigen production for vaccines, an attractive alternative for controlling diseases by mass vaccination.…”

“…Many foreign proteins have been expressed in plants that cannot be eaten raw, such as potato, or unsuitable for human consumption, such as tobacco. Since heat can denature plant-produced proteins (Kong et al 2001;Marquet-Blouin et al 2003), plants that can be eaten raw, such as fruits or carrots, represent an interesting alternative.…”

Overexpression of human virus surface glycoprotein precursors induces cytosolic unfolded protein response in Saccharomyces cerevisiae

“…Unglycosylated MeH molecules are not detected in the preparations of this protein after synthesis in mammalian expression system [ 16 ], however the expression of the MeH protein in insect cells by baculovirus system resulted in a large amount (approximately half of the total product corresponding to 65 kDa species) of unglycosylated MeH protein molecules [ 31 ]. The recombinant MeH protein, produced in transgenic carrot plants also had lower molecular weight than the viral protein, suggesting a different glycosylation pattern, but this was not further explored [ 32 ]. It appears that maturation of MeH protein is increasingly impaired switching from mammalian cell culture to less complex expression systems, and in lower eukaryotes (e.g.…”

Research Progress of a Potential Bioreactor: Duckweed

“…For example, cholera toxin B subunit was transferred into potatoes that worked as edible vaccines [ 6 , 7 ]. Marquetblouin et al [ 8 ] obtained the immunodominant antigen of measles virus by transforming it into carrots. Based on these results, transgenic plants might serve as effective expression systems for the production of recombinant proteins in the biopharmaceutical industry [ 9 ].…”