Oral administration of tobacco seeds expressing antigenic proteins in mice Balb-C: a model of edible vaccines for oedema disease

Oedema disease of pigs is an enterotoxaemia affecting pigs aged 4 to 12 weeks and responsible of considerable economic losses. The oedema disease is caused by the extra-intestinal effects of Shiga-like toxin II variant, SLT-Iiv or VT2e. SLT are bipartite molecules composed of a single enzymatic intracellularly active A-subunit and a pentamer of B-subunit (Bertschinger and Gyles, 1994), which trigger attaching to the specific gastrointestinal receptor. Moreover pathogenic Escherichia coli bacteria possess one or more virulence factors which affect the capability of the germ to cause the disease (Imberechts et al., 1992). The F18 fimbriae are present as long flexible filamentous structures related to verocitotoxic E.coli strains. Intestinal colonization with a live E.coli strains resulted in significantly increased level of anti-fimbrial F18 antibodies, especially IgA, in serum and intestinal wash fluids. Numerous studies have shown that viral epitopes and subunits of bacterial toxins can be expressed and correctly processed in transgenic plants (Rossi et al., 2002a).....