IN VITRO CO-STIMULATORY ACTIVITY OF HUMAN B7.2(IgV+C)PROTEIN PRODUCED BY ENGINEERED BACTERIA

Objective To express human B7. 2 extracellular domain with prokaryote expression system and to evaluate its biological activity in vitro. Methods PCR was used to amplify the extracellular region of human B7. 2 which contained both the IgV and IgC domains. The recombinant PGEX-4T-3/hB7. 2 (IgV C) was obtained by cloning the PCR product into a prokaryote expression plasmid PGEX-4T-3 and was transformed into the host strain of DH5-a. Tke fusion protein consisted of GST and hB7. 2(IgV C) was identified by SDS-PAGE and Western blotting. T cell activation was observed by exposing purified T lymphocytes to the fusion protein and 3H]-TdR incorporation with the presence of the first signal imitated hy anti-CD3 antibody. Results The fusion protein GST-hB7. 2 (IgV C) was produced and detected in inclusive body form from engineered bacterial cells. With the first signal existed,T lymphocytes proliferated when it was co-stimulated by the fusion protein. Conclusion These results indicated that the functional human B7. 2(IgV C) fusion protein can be produced in bacterial cells and the fusion protein displays the co-stimulatory activity in T lymphocytes activation.