Immunogenicity of recombinant LT-B delivered orally to humans in transgenic corn. Vaccine

Center for Vaccine Development, University of Maryland School of Medicine, 685 West Baltimore Street, Baltimore, MD 21201, USA.
Vaccine (Impact Factor: 3.49). 11/2004; 22(31-32):4385-9. DOI: 10.1016/j.vaccine.2004.01.073
Source: PubMed

ABSTRACT Previous clinical studies have demonstrated the feasibility of using edible transgenic plants to deliver protective antigens as new oral vaccines. Transgenic corn is particularly attractive for this purpose since the recombinant antigen is stable and homogeneous, and corn can be formulated in several edible forms without destroying the cloned antigen. Transgenic corn expressing 1 mg of LT-B of Escherichia coli without buffer was fed to adult volunteers in three doses, each consisting of 2.1 g of plant material. Seven (78%) of nine volunteers developed rises in both serum IgG anti-LT and numbers of specific antibody secreting cells after vaccination. Four (44%) of nine volunteers also developed stool IgA. Transgenic plants represent a new vector for oral vaccine antigens.

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    • "Intestinal mucosa represents an attractive target for oral delivery of immunogens and for mucosal vaccination. Several oral strategies, using biodegradable polymeric particles [6] [7], liposome [8], bacterial ghost [9], plant lectins [10] [11], adjuvanted vaccines [12] or transgenic plants [13] [14], have been adopted to protect the antigens in the gastrointestinal tract and to increase uptake by DCs, causing their maturation and their migration to the intrafollicular areas. PLA (poly(lactic acid)) or PLGA (poly(lactic-co-glycolic acid)) nanoparticles are suitable protein carriers offering antigen protection , increased penetration across mucosal surface and controlled release of encapsulated antigen [15]. "
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    ABSTRACT: Peyer's patch have been extensively studied as a major inductive site for mucosal immunity within the small intestine. The intestinal mucosa contains numerous dendritic cells, which induce either protective immunity to infectious agents or tolerance to innocuous antigens, including food and commensal bacteria. Although during the past few years, several subsets of human mucosal dendritic cells have been described, a precise characterization of the different mouse mucosal dendritic cells subpopulations remains to be achieved with regard to their phenotype and localization in Peyer's patch. In this report, we have investigated by immunofluorescence on cryosection and by flow cytometry, the phenotype and the localization of dendritic cells into Peyer's patch of C57Bl/6 mouse intestine using dendritic cells markers. Positive and double staining for CD11c and BDCA-2, pDC/IPC, DC-LAMP, DC-SIGN, TLR8 and Langerin have been observed revealing new mouse intestinal DC subsets. This study provides new insight in the understanding of mucosal immune responses induced by natural processes as infections but also new perspectives for the evaluation of oral vaccines.
    Vaccine 03/2011; 29(20):3655-61. DOI:10.1016/j.vaccine.2011.03.012 · 3.49 Impact Factor
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    • "The expression level of both B subunits, measured by quantitative ELISA, varied between 0.5 and 2.7% of the total soluble protein (TSP), which represents about 1.3 mg/g seed recombinant protein. According to Tacket et al. (2004) this level of protein expression is sufficient to generate a sizeable amount of antigen after the consumption of a few milligrams of seeds, and the transgenic rice lines can be used for the production of rice seed-based edible vaccines. "
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    ABSTRACT: Seed is an ideal protein production platform because it is the storage organ of the plant and offers appropriate storage compartments for the deposition of foreign proteins. To achieve high foreign protein expression level in the endosperm tissue, the transformation cassette carried the tissue-specific promoter of the wheat high-molecularweight glutenin subunit protein 1Bx17, fused to the first intron of rice actin promoter. Transformation protocols were established and optimized in the laboratory for cereals such as rice, barley and wheat using direct DNA delivery and the Agrobacterium tumefaciensmediated transformation system. Both immature (barley) and mature (rice) embryos, and immature inflorescences (wheat) were used as sources of explants. Subunit edible vaccines were produced to introduce the LTB, CTB and fused LTB-PEDV genes into the rice genome. The PEDV gene was also integrated into the barley genome. A project has recently been started to produce a rabbit-derived enzyme in transgenic wheat endosperm to be used by the pharmaceutical industry.
    Acta Agronomica Hungarica 03/2010; 57(1):55-64. DOI:10.1556/AAgr.58.2010.1.7
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    • "In addition, the elicited antibody response is capable of partial protection against LT challenge, and results in an immunogenic response in human subjects (Tacket et al., 1998). Similar findings have been reported for maize-derived LTB (Chikwamba et al., 2002a,b; Tacket et al., 2004). Recently, our research group has reported on the expression of a synthetic LTB gene in carrots, resulting in LTB-containing tubers capable of inducing a mucosal immune response and providing protection against the cholera toxin in mice (Rosales-Mendoza et al., 2007, 2008). "
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    ABSTRACT: Enterotoxigenic Escherichia coli (ETEC) strains are important pathogens in developing countries. Some vaccine formulations containing the heat labile toxin B subunit (LTB) have been used in clinical trials; however, the induction of neutralizing antibodies against the heat-stable toxin (ST), a poor immunogenic peptide, is necessary, as most ETEC strains can produce both toxins. In this study, a plant optimized synthetic gene encoding for the LTB-ST fusion protein has been introduced into plastids of tobacco leaf tissues, using biolistic microprojectile bombardment, in an effort to develop a single plant-based candidate vaccine against both toxins. Transplastomic tobacco plants carrying the LTB-ST transgene have been recovered. Transgene insertion into the plastid was confirmed by both PCR and Southern blot analysis. GM1-ELISA revealed that the LTB-ST fusion protein retained its oligomeric structure, and displayed antigenic determinants for both LTB and ST. Western blot analysis, using LTB antisera, confirmed the presence of a 17-KDa protein in transplastomic lines, with the correct antigenicity of the fusion protein. Expression levels of this fusion protein in different lines reached up to 2.3% total soluble protein. Oral immunization of mice with freeze-dried transplastomic tobacco leaves led to the induction of both serum and mucosal LTB-ST specific antibodies. Following cholera toxin challenge, a decrease of intestinal fluid accumulation was observed in mice immunized with LTB-ST-containing tobacco. These findings suggest that tobacco plants expressing LTB-ST could serve as a plant-based candidate vaccine model providing broad-spectrum protection against ETEC-induced diarrhoeal disease.
    The Plant Journal 09/2008; 57(1):45-54. DOI:10.1111/j.1365-313X.2008.03666.x · 6.82 Impact Factor
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