construction of a novel dna vaccine candidate encoding an hspx-ppe44-esxv fusion antigen of mycobacterium tuberculosis

background: mycobacterium tuberculosis is the causative agent of tuberculosis (tb). bacille calmette-guerin (bcg) vaccine, is not effective in adults, therefore, many efforts have been made to produce an effective adult tb vaccine. the aim of this study was to develop a new tuberculosis dna vaccine candidate encoding a recombinant hspx-ppe44-esxv fusion antigen of m. tuberculosis. methods: a fusion dna segment consisting of hspx, linker, ppe44, linker, and esxv, after codon optimization, was designed. the fusion dna was cloned and its sequence confirmed. then, expression of a recombinant pcdna3.1 (+)/hspx-ppe44-esxv plasmid in chinese hamster ovary (cho) cells was verified by rt-pcr and western-blot analysis. results: a 1968 bp band in rt-pcr and a 68 kda band on western-blot analysis confirmed transcription and expression of recombinant hspx-ppe44-esxv in eukaryotic cells. conclusions: a recombinant dna segment encoding the hspx-ppe44-esxv fusion antigen of m. tuberculosis was constructed and considered to be tested as a new tb dna vaccine candidate.