A plant-based multicomponent vaccine protects mice from enteric diseases

Cholera toxin (CT) B and A2 subunit complementary DNAs (cDNAs) were fused t o a rotavirus enterotoxin and enterotoxigenic Escherichia coli fimbrial ant igen genes and transferred into potato. Immunoblot and enzyme-linked immuno sorbent assay (ELISA) results indicated that the fusion antigens were synth esized in transformed tuber tissues and assembled into cholera holotoxin-li ke structures that retained enterocyte-binding affinity. Orally immunized m ice generated detectable levels of serum and intestinal antibodies against the pathogen antigens. Elevated levels of interleukin 2 (IL2) and interfero n gamma (INF gamma) detected in immunogen-challenged spleen cells from the immunized mice indicated the presence of a strong Th 1 immune response to t he three plant-synthesized antigens. This result was supported by flow cyto metry analysis of immunized mouse spleen cells that showed a significant in crease in CD4(+) lymphocyte numbers. Diarrhea symptoms were reduced in seve rity and duration in passively immunized mouse neonates following rotavirus challenge. The results suggest that food plants can function as Vaccines f or simultaneous protection against infectious virus and bacterial diseases.