Expression system for enhancing solubility and immunogenicity of recombinant proteins. The expression system includes a protein expression vector that contains a chimeric gene encoding a chimeric protein comprising: (a) a first polypeptidyl fragment at the N-terminal end of the chimeric protein, containing a protein transduction domain (PTD), or a fragment thereof, having HIV Tat PTD activity; (b) a second polypeptidyl fragment at the C-terminal end of the first polypeptidyl fragment, containing a J-domain, or a fragment thereof, having heat shock protein 70 (Hsp70)-interacting activity; and (c) a third polypeptidyl fragment at the C-terminal end of the second polypeptidyl fragment, containing a target protein or polypeptide.