The expression and identification of recombinant pET28a-Streptag I-SbpA-Ag85B Plasmid

Objective To obtain nanometer Ag85B protein by the molecular cloning techniques and identify its immunological characteristics.Methods The gene sllB coding surface layer protein (S-layer)was truncated and linked with the Mycobacterium tuberculosis secreted protein Ag85B gene.The expression plasmid pET28a-Streptag I-SbpA-Ag85B was transformed into E.coli,the protein was identified by SDS-PAGE and Western blotting.Results The expression system was developed successfully for recombinant nanometer-scale antigen and the fusion protein was identified by SDS-PAGE with correct molecular weight and can be recognized by the serum of tuberculosis patients.Conclusion The recombinant Ag85 B protein has strong immune reaction and small size on nanometer level,this expression system provides a new way for the tuberculosis vaccine design. Key words: Ag85B ;  Prokaryotic expression ;  Nanometer ;  Immunogenicity