Construction of a eukaryotic expression system with stable and secretory expression of mycobacterium tuberculosis 38kDa protein.

Abstract

The 38kDa protein is a major antigen of mycobacterium tuberculosis and has been widely used in TB serodiagnosis, due to its highly sensitivity and specificity. Here we attempt to establish a production platform of recombinant 38kDa protein in mammalian cells and to evaluate the potential value of 38kDa protein in TB serodiagnosis. The 38kDa gene is synthesized and cloned into a lentiviral expressing vector. Recombinant lentiviral vector LV-CMV-38kDa-eGFP was packaged, titered, and then transduced into HEK 293T cells. Recombinant cell lines were selected by limiting dilution. Supernatants were collected and purified by HisTrapTM HP column. Western blot showed a molecular weight of approximate 38kDa in cell supernatants as expected. ELISA assay confirmed the immunological specificity of the obtained protein in the presence of MTB-infected human serum samples. In all, we have obtained a stable cell line with long-term and robust expression ofsecretory MTB 38kDa protein, which may provide a promising candidate antigen for the development of TB serological diagnosis.