has role protective antigen role protective antigen Hepatitis B virus protein PreS2 middle surface protein Oliver He Allen Xiang Protegen ID: 496; NCBI Protein GI: 113207330; NCBITaxon: 10407 The immunological protection of pVAX-PS, a DNA vaccine, was assessed in the tree shrews model. pVAX-PS was constructed by inserting the gene encoding the middle (pre-S2 plus S) envelope protein of HBV into a plasmid vector pVAX1. Results indicated that pVAX-PS immunization could induce remarkable humoral immune response and prevent the experimental tree shrews from infection of HBV [PubMed: 12932306]. protein