USE OF THE RECOMBINANT 38-KDA ANTIGEN OF MYCOBACTERIUM-TUBERCULOSIS AS AN IMMUNOGEN FOR SPECIFIC ANTISERA PRODUCTION

The Mycobacterium tuberculosis 38-kDa protein antigen is one of the se creted immuno-dominant antigens showing high immunogenicity at B-cell and T-cell levels. Although monoclonal antibodies to this antigen have been produced, specific polyclonal antisera is required for standardi zation of specific immunodiagnostic assays. This protein has been over expressed and purified from recombinant Escherichia coli using an indu cible vector system. During each stage of expression and purification, the recombinant protein was used to immunize mice and rabbits by seve ral methods: 1) as overexpressed protein present as inclusion bodies i n recombinant E. coli; 2) embedded in a polyacrylamide gel; 3) fixed t o a solid-phase nitrocellulose membrane and 4) emulsified with an adju vant. All strategies yielded specific antisera as determined by enzyme -linked immunosorbent assay (ELISA) and immunoblot analyses. The resul ts obtained, both quantitative (ELISA) and qualitative (immunoblot) de monstrate that the purified recombinant antigen retains its antigenici ty and immunogenicity throughout the various steps in the process of e xpression and purification and serves as a potent antigen for producti on of specific antisera to be used in immunoassays.