Recombinant human B7.2 IgV-like domain expressed in bacteria maintains its co-stimulatory activity in vitro / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate which of the two immunoglobulin (Ig)-like domains, the immunoglobulin variable region homologous domain IgV (hB7.2 IgV) and the immunoglobulin constant region homologous domain IgC (hB7.2 IgC) on the human B7.2 molecule contains receptor binding sites, and to evaluate whether the B7.2 protein expressed in bacteria has biological activity in vitro.</p><p><b>METHODS</b>Three fragments of hB7.2 IgV,hB7.2 IgC and the complete extracellular region of human B7.2 containing both the IgV and IgC domains,hB7.2 Ig (V+C), were amplified by PCR and subcloned into pGEM-Teasy. Three recombinants,pGEX-4T-3-hB7.2 IgV,pGEX-4T-3-hB7.2 IgC and pGEX-4T-3-hB7.2 Ig (V+C), were generated by cloning the fragments into a prokaryote expression plasmid (pGEX-4T-3) and transformed into the host strain E. coli DH5alpha. The relevant target fusion proteins consisting of GST and hB7.2 IgV,hB7.2 IgC and hB7.2 Ig (V+C), were identified by SDS-PAGE and Western blotting. With the presence of the first signal imitated by anti-CD3 antibody, T cell activation was observed by exposing purified T lymphocytes to each soluble form of the three bacterially-produced human B7.2 fusion proteins by [(3)H]-TdR incorporation.</p><p><b>RESULTS</b>Three recombinant fusion proteins of human B7.2, GST-hB7.2 IgV, GST-hB7.2 IgC and GST-hB7.2 Ig (V+C) were produced and detected in inclusion body form from engineered bacteria. With the first signal present,T lymphocytes proliferated when co-stimulated by bacterially-produced either GST-hB7.2 Ig (V+C) or GST-hB7.2 IgV fusion proteins, but not by GST-hB7.2 IgC.</p><p><b>CONCLUSIONS</b>Functional human B7.2 fusion protein can be produced in bacteria. The IgV-like domain of human B7.2 is sufficient for B7.2 to interact with its counter-receptors and co-stimulate T lymphocytes.</p>

IN VITRO CO-STIMULATORY ACTIVITY OF HUMAN B7.2(IgV+C)PROTEIN PRODUCED BY ENGINEERED BACTERIA / 药物分析学报

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. 2which 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-α. The 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 by 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.

THE EUKARYOTIC EXPRESSION OF HUMAN PERFORIN PROTEIN AND THE ESTABLISHMENT OF HYBRIDOMAS PRODUCING ANTI-HUMAN PERFORIN PROTEIN / 药物分析学报

Objective To prepare the monoclonal antibody against human perforin(HP). Methods Recombinant eukaryotic expression plasmid pCDM8-HP was extracted and purified, and the BALB/C mice were immunized with the plasmid. The hybridomas producing anti-HP McAbs were established by using hybridoma technique, then the specificity of the McAbs was identified by using immunocytochemical technique and Western blot. Results Three hybridoma cell lines secreting McAbs against human perforin were established, and the three McAbs showed positive only with LAK cells containing human perforin protein, and showed negative with inactive human peripheral blood lymphocytes (PBLs). The subclasses of the three McAbs were determined as lgG2bK. Western blot results showed that the three McAbs recognized a specific band of LAK cell lysateds with molecular weight of 70.0Kd. Conclusion The three hybridoma cell lines secreting McAbs against human perforin were established and the secreted McAbs were specific.