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Over the last 2 decades, the number of emergent infectious diseases has increased at an alarming rate. Also disheartening is the rise of known infectious pathogens that have acquired extensive drug resistance and reemerged with greater virulence. More recently, the threat of bioweapons has rekindled an urgency for the development of mass immunization programs. In response to this increased infectious disease threat, efforts have been intensified to identify more effective, inexpensive, and more easily deliverable mucosal vaccination methods. One area of research currently under development is the genetic modification of plants for production of immunoprotective proteins. The ability of plants to synthesize complex proteins using the elements of sunlight, soil, air, and water makes them ideal organisms for harvesting large quantities of therapeutic proteins. The introduction of antigen or antibody encoding genes into the genome of a plant through stable transformation enables them to manufacture vaccine proteins that are directly applicable for use in disease treatment, unlike yeast, bacterial, insect or other expression systems that require purification steps before delivery. As an alternative to stable transformation, plants can be used to generate large quantities of vaccines by acting as hosts for genetically altered plant viruses in which antigen proteins can be expressed and later purified from infected plant tissues. In this review, we survey current experimental strategies for using edible plants to achieve passive and active immunization against infectious disease organisms. In addition, methods are described for the construction of transformed plants that can provide protection against autoimmune diseases. Concerns and present obstacles to effective immunization with plant-based vaccines for animals and humans are presented. [ABSTRACT FROM AUTHOR]

An abstract of the article "Oral Delivery of Recombinant Vaccinia Viruses Expressing Adjuvanted Islet Autoantigens Protects NOD Mice from Autoimmune Diabetes," by William H. R. Langridge, Bela Denes, Nadia Fodor, John Hough, Jie Yu and Istvan Fodor is presented.

Abstract: A fusion protein containing the shiga toxin-1 B subunit (STB) linked to a 90 amino acid peptide (aa residues 86–175) from simian rotavirus (SA-11) nonstructural protein NSP4 was synthesized in Escherichia coli. Mice orally inoculated with 60μg of STB::NSP490 fusion protein per dose generated higher humoral and intestinal antibody titers than mice inoculated with 30μg of NSP4 alone. Serum anti-NSP4 IgG2a isotype titers were substantially greater than IgG1 titers, suggesting a dominant Th1 immune response. ELISA measurement of cytokines secreted from splenocytes isolated from immunized mice confirmed the STB::NSP490 fusion protein stimulation of a strong Th1 cell mediated immune response. Diarrhea in SA-11 rotavirus challenged neonates suckling from STB::NSP4 immunized dams was significantly reduced in severity and duration in comparison with virus challenged neonates from unimmunized mice. Together, our experiments demonstrate for the first time that the shiga toxin B subunit provides ligand mediated delivery of virus antigens to the gut-associated lymphoid tissues for enhanced stimulation of humoral and cellular responses against rotavirus gastroenteritis. [Copyright &y& Elsevier]

A cDNA encoding the Simian immunodeficiency virus type (SIVmac) Gag capsid protein was introduced into Solanum tuberosum cells by Agrobacterium tumefaciens-mediated transformation methods. The gag gene was detected in the genomic DNA of transformed leaf tissues by PCR DNA amplification. Immunoblot analysis of transformed potato plant extracts with anti-Gag monoclonal antibody showed that biologically active Gag protein was synthesized in transformed tuber tissues. Based on ELISA results, recombinant Gag protein made up 0.006–0.014% of total soluble tuber protein. The synthesis of SIV Gag in transformed potato tubers opens the way for development of Gag-based edible plant vaccines for protection against SIV and potentially HIV-1 infection. [Copyright &y& Elsevier]