[Overexpression, purification of recombinant HIV-1 gp41 protein and detection of HIV antibody in urine].

OBJECTIVE: To establish a specific and sensitive Enzyme-linked immunosorbent Assay (ELISA) kit for detection of HIV-1 antibody in urine using Escherichia coli expression products as coating antigen. METHODS: The truncated HIV-1 gp41 gene fragment of major antigenic epitopes was inserted into the plasmid pET22b to obtain expression plasmid pET22b-mgp41. The recombinant antigen was expressed in BL21 (DE3) strains of Escherichia coli and was purified by immobilized metal chelation and gel filtration chromatography. Using this antigen as coating antigen, a HIV-1 urine antibody ELISA kit was developed. In order to examine the clinical utility of the kit, 5437 urine samples were assayed, which consisted of 641 urine samples from HIV infected patients and 4796 samples from normal subjects. Results The purity of purified antigen is up to 95%. Anti-HIV antibodies were detected in all the urine samples from HIV infected patients, and the diagnostic sensitivity for HIV-1 infection was 100%. In healthy control group, 71 cases showed false positive, the specificity was 98.52%. CONCLUSION: The HIV-1 urine antibody kit can be used in screening and diagnosing for HIV-1 infection.