Objective   To express the sever al linked antig en epitopes of envelop genes of HIV1/2 types in the system of prokaryotic expression vector; to purify and to identify the expressing products.

  Methods   In order to construct the recombinant expressing plasmid pRSET B-env, the linked genes contained two antigen epitopes of gp 41, three different antigen epitopes of gp 120 and two antigen epitopes of gp 36 were inserted into pRSETB vector.After transforming into E.coli BL 21 (DE3) cells.The recombinant protein was expressed with induction of isopropy 1β-D-thiogalactopyranoside(IPTG), and was purified by immobilized metalion affinity chromatograph and was recoveried by dialysis in urea of slowby decreasing concentration.The immunoactivity was analyzed by westernblot and Enzyme-linked immunosorbent assay(ELISA).

  Results   An expected about 32KD expressing protein band could be seen with sodium dodecyl sulfate-poly acrylamide gel electrophoresis (SDS-PAGE). The aim genes revealed higherexpressive rate in E.coli BL 21 (DE3) cells.The results of westernblot and ELISA showed specific reactions with HIV patients' sera, and no cross-reaction with other patients.ser a using the expressing protein.

  Conclusion   The recombinant expressing plasmid pRSET B-env which contained the several linked antigen epitopes of envelop genes of HIVwas successfully constructed.After purification, the expressing protein possessed higher pureness, good specificity and activity.