Cloning, expression, purification and immunoreactivity analysis of gag derived protein p17 from HIV-1 CRF35 in fusion with thioredoxin from human subjects

So far, recombinant antigens of HIV-1, the etiologic cause of Acquired Immunodeficiency Syndrome (AIDS), have been widely used for the diagnosis and vaccine development. P17 or the matrix protein formed by the proteolytic cleavage of gag is strongly antigenic and is as conserved and immunogenic as p24. In some cases, antibodies to p17 are more prevalent than antibodies to p24 and the decline in the level of p17 antibodies is an earlier prognostic marker for disease progression than decline in the level of antibodies to p24. The aim of this study was to clone and express the gag derived p17 protein in soluble form in E. coli and then assess the immunoreactivity of produced recombinant p17. DNA sequence encoding p17 matrix protein was cloned from PTZ-gag53-IR vector that has the complete gag polyprotein sequence. The T7-promoter-based expression system used in this study was TOPO directional cloning strategy that expressed p17 matrix protein in fusion with thioredoxin in E. Coli. Purification of produced recombinant protein has been done using Ni-NTA nickel chelating agarose beads. Sequencing result of the cloned sequence showed that it belongs to CRF35_AD subtype of HIV-1 which is highly prevalent in Iran and Afghanistan. The immunoreactivity of produced recombinant p17 to sera from infected individuals showed 93.8% sensitivity and 100% specificity.