Overexpression and purification of human immunodeficiency virus type 1 env derived epitopes in Escherichia coli

In order to develop a reliable and inexpensive serodiagnostic method, a part of envelope gene of HIV-1, gp120' and gp41' (HIV-1 env a.a. 295-474 and a.a. 556-647) was cloned into a T7 expression vector (pET3d). The fusion protein (gp120'-gp41') was overexpressed in Escherichia coli, then purified to homogeneity by a simple gel filtration chromatography. Western blot analysis and enzyme-linked immunosorbent assay (ELISA) using the purified fusion protein showed a high sensitivity and a specificity for the detection of anti HIV-1 antibodies in testing human plasma. These results suggest that the expression scheme employing a direct expression vector and the rapid purification method are reliable and applicable for obtaining a large quantity of HIV-1 env protein for diagnoses of HIV-1 infections.