AIM:To investigate the expression of recombinant HBsAg(rHBsAg) in transgenic cherry tomatillo in order to explorethe feasibility of producing HBV oral vaccine with cherrytomatillo by animal immune tests.METHODS:The recombinant plant expression vectorcontaining HBsAg gene was constructed.Mediated withAgrobacterium tumefaciens,HBsAg gene was transferred intocotyledons of cherry tomatillo.Transformed cherry tomatilloswere obtained through hygromycin delay-selection.IntegratedDNA in transgenic cherry tomatillo was confirmed byhygromycin resistance selection,Gus detection,polymerasechain reaction (PCR) and dot blotting analysis.Antigenicity ofrHBsAg was examined by ELISA and the immunogenicity ofrHBsAg derived from transgenic cherry tomatillo tissues wasconfirmed by oral feed of transformed tissues to BALB/c miceprimed with commercial HBV vaccines.Specific antibody titersin mice’s serum were examined by ELISA every week.RESULTS:By far,10 positive lines of transgenic cherrytomatillos containing HBsAg gene were obtained.Amongdifferent organs of the same transgenic cherry tomatillo,level of rHBsAg expressed in leaves was the highest withthe yield up to 300ng/g fresh weight.And the rHBsAgexpression level in fruits was about 10 ng/g fresh weight.In animal immune tests,oral delivery with transgenic tissuesto mice primed with commercial vaccine instead of naivemice resulted in significant immune response.CONCLUSION:The result of this animal immune testindicated the rHBsAg derived from transgenic cherry tomatillopossessed normal immunogenicity.This work demonstratedthe feasibility to generate oral immunogenic rHBsAg intransgenic cherry tomatillo,and would provide someexperimental approach for the production of low-cost oralvaccines using transgenic cherry tomatillo in large scale. AIM: To investigate the expression of recombinant HBsAg (rHBsAg) in transgenic cherry tomatillo in order to explore the feasibility of producing HBV oral vaccine with cherry tomatillo by animal immune tests. METHODS: The recombinant plant expression vector containing HBsAg gene was constructed. Mediated with Agrobacterium tumefaciens, HBsAg gene was transferred intocotyledons of cherry tomatillo. Transformed cherry tomatilloswere obtained through hygromycin delay-selection.Integrated DNA in transgenic cherry tomatillo was confirmed byhygromycin resistance selection, Gus detection, polymerasechain reaction (PCR) and dot blotting analysis. Antigenicity of rHBsAg was examined by ELISA and the immunogenicity of rHBsAg derived from transgenic cherry tomatillo tissues wasconfirmed by oral feed of transformed tissues to BALB / c miceprimed with commercial HBV vaccines. Specific antigens titersin mice ’serum were examined by ELISA every week .RESULTS: By far, 10 positive lines of transgenic cherrytomatillos contain ing HBsAg gene were obtained.Amongdifferent organs of the same transgenic cherry tomatillo, level of rHBsAg expressed in leaves was the highest with the yield up to 300 ng / g fresh weight. And the rHBsAgexpression level in fruits was about 10 ng / g fresh weight.In. animal immune tests, oral delivery with transgenic tissuesto mice primed with commercial vaccine instead of naivemice resulted in significant immune response. CONCLUSION: The result of this animal immune testindicated the rHBsAg derived from transgenic cherry tomatillopossessed normal immunogenicity. This work demonstrated the feasibility to generate oral immunogenic rHBsAg intragenic cherry tomatillo, and would provide some experimental approach for the production of low-cost oral vaccines using transgenic cherry tomatillo in large scale.