Cloning, expression and purification of HIV integrase and evaluation of its antigenicity

Improving the performance of HIV diagnosis assays is one of the most important ways to reduce HIV transmission. Because of the high mutation rate of HIV, it is critical to use the conserved proteins to develop diagnostic immunoassay methods. Because integrase is one of the most conserved proteins of HIV, it may be a good target for this purpose. In this paper cloning, purification and immunogenicity evaluation of integrase are studied. Integrase coding sequence was cloned in pET28a expression vector. After transformation of recombinant plasmid to E. coli, protein expression was induced by IPTG. Immunogenicity of recombinant integrase was evaluated by western blotting. The protein was purified by Ni-NTA affinity chromatography. Induction by IPTG leads to expression of integrase. The expression level after optimization of conditions was about 40% of total proteins of E. coli. Western blotting showed specific immunoreactivity of recombinant integrase to HIV infected sera. The yield of produced protein was 75 mg per one liter of bacterial culture. The produced protein retains antigenic properties and can be used in diagnostic immunoassay methods. Optimization of culture and protein expression conditions results in recombinant bacteria producing high yields of protein which may be used in industrial purposes.