[Establishment of a THP-1 macrophage model infected by recombinant Mycobacterium smegmatis expressing green...

Objective To establish a THP-1 macrophage model infected by Mycobacterium smegmatis expressing green fluorescent protein (GFP), to quickly locate and visually detect Mycobacterium smegmatis, and to provide a tracer tool to identify the pathogenesis of tuberculosis and develop new tuberculosis vaccines. Methods The enhanced green fluorescent protein (EGFP) gene sequence was amplified by PCR using pEGFP-N1 plasmid as a template to obtain the coding gene of EGFP, and the amplified product was cloned into the vector pALACE to establish the recombinant plasmid pALACE-EGFP. Electroporation transformed the pALACE-EGFP into Mycobacterium smegmatis, and recombinant Mycobacterium smegmatis clones were screened by hygromycin resistance. After expanded culture, the smears were observed by fluorescence microscopy. The THP-1 macrophages were infected with recombinant Mycobacterium smegmatis, and the expression of EGFP was observed. Results The recombinant plasmid pALACE-EGFP was constructed appropriately. The recombinant Mycobacterium smegmatis was observed under fluorescence microscope. And it was confirmed that EGFP was expressed in recombinant Mycobacterium smegmatis, and THP-1 macrophages emitted green fluorescence after infection. Conclusion The successful establishment of recombinant Mycobacterium smegmatis expressing EGFP protein provides insights for investigating infection and pathogenesis of Mycobacterium tuberculosis.