expression of hepatitis b virus core antigen in native and fusion forms in e. coli

dna coding for the core antigen from hepatitis b virus (hbcag) was amplified, cloned and propagated in e. coli. the core protein was expressed in e. coli and the product was readily detected by western blot. this protein can be used as a diagnostic material in serum screening tests. to increase the level of expression of this antigen in bacteria, two plasmids were constructed in which the gene coding for n-terminal part of the human il-2 has been fused to 5¢ -terminus of the core antigen gene under control of the tryptophan promoter. although the expression level of core antigen from hepatitis b virus in e. coli was increased in fusion forms, but the size of fusion partner could affect the antigenicity, particle formation and assembly of the core antigen. the native and the two fusion forms of the core antigens from hepatitis b virus were evaluated as a diagnostic material in serum screening.