Rapid and simple purification of human immunodeficiency virus 1 epitope gp41

In order to develop a reliable and inexpensive serodiagnostic method, part of the transmembrane glycoprotein gene of HIV-1, gp41', (HIV-env 548-646) was cloned into an expression vector, pCT10 with a sequence encoding a hydroxylamine cleavage site and with a part of Lac Z gene (Lac 2": 834 base pairs) as a fusion partner. Overexpression of Lac Z"-gp41' was induced in E. coli and the gp41' fusion protein was purified to homogeneity by centrifugation, hydroxylamine cleavage and an ion-exchange chromatography. Western blot analysis and enzyme-linked immunosorbant assay (ELISA) using the purified gp41 fragment showed high sensitivity and specificity of gp41 as an antigen to detect anti HIV-1 antibodies in testing human sera. These results suggest that this simple and rapid purification method is reliable for obtaining a large quantity of purified gp41'.