Provided is a nucleic acid molecular, comprising a nucleotide sequence coding a polypeptide carrier. Also provided are a recombinant protein comprising the polypeptide carrier and a target polypeptide, and uses of the nucleic acid molecular and the recombinant protein. Also provided is a vaccine or pharmaceutical composition that can be used for prevention, alleviation, or treatment of HBV infections or HBV infection-related diseases (for example, hepatitis B), the composition comprising the polypeptide carrier and a recombinant protein from an HBV epitope.
