The anti-pathogen vaccine of the present invention is produced in recombinant bacteria and/or transgenic plants and then administered through standard vaccine introduction method or through the oral administration. A DNA sequence encoding for the expression of an antigen of a pathogen is isolated and ligated to a promoter which can regulate the production of the surface antigen in a bacterial or transgenic plant. Preferably, a foreign gene is expressed in a portion of the plant or bacteria, and all or part of the antigen expressing plant or bacteria used for vaccine administration. In a preferred procedure, the vaccine is administered through the consumption of the edible plant as food, or the bacteria administered orally. The present invention also provides a method of using genetically modified microorganisms generally recognized to be edible and/or harmless to animals or humans when ingested, such as lactic acid bacteria, including Lactococcus lactis strains, as oral vaccines. In one embodiment, Lactococcus lactis expressing the avian influenza HA gene can be used as an oral vaccine for protection against H5N1 virus infection.
