ABSTRACT
@#[Abstract] Objective: To construct and purify the recombinant bispecific antibody (BsAb) targeting PD-1 and CD19 and evaluate its activity. Methods: With pCAR1 plasmid as the vector, the eukaryotic expression vector of anti-PD-1/CD19 BsAb was constructed by molecular cloning technology, and then transfected into mammalian cell line CHO-S by PEI reagent for transiently expressing antibody. The BsAb was purified by Affinity chromatography and then identified by SDS-PAGE and WB. The blocking activity of BsAb on PD-1/PD-L1 in vitro was detected by Luciferase reporter gene assay. The activity of antibody (BsAb)-dependent cell (PBMC)-mediated cytotoxicity (ADCC) in vitro was evaluated by lactate dehydrogenase (LDH) cytotoxicity assay. Results: The double plasmid eukaryotic expression vector pCAR1-19X3 was successfully constructed, and anti-PD-1/CD19 BsAb was successfully expressed in CHO-S cells, named pCAR1-19X3-TY. pCAR1-19X3-TY could effectively block the binding of PD-1 to its ligand PD-L1 in vitro, and the EC50 based on the dose-response curve was 0.306 μg/ml. ADCC results showed that pCAR1-19X3-TY could mediate the cytotoxicity of PBMC against Raji cells, and the curve showed a linear upward trend; when the effect/target ratio was 50∶1, the target cell lysis rate of pCAR1-19X3-TY was (38.9±0.3)%, which was not significantly different from that of the positive treatment group (46.7±4.9)% (P>0.05), but significantly higher than that of the negative control group (1.2±0.1)% (P<0.05). Conclusion: The recombinant anti-PD-1/CD19 BsAb can effectively block the binding of PD-1 and PD-L1 and activate PBMC mediated cytotoxicity against Raji cells. pCAR1-19X3-TY has the potential application value in the treatment of B-cell malignant tumor.
ABSTRACT
Aims: Find a suitable method for the protein extraction from flower buds of Solanum lycopersicum. Study Design: Compare some kinds of protein extraction methods and find the best one among them suitable to tomato flower buds. Place and Duration of Study: Biological Science and Technology College, between June 2010 and July 2011. Methodology: The proteins for electrophoresis were extracted using different methods, such as trichloroacetic acid /acetone (TCA/acetone), Sodium dodecyl sulfate (SDS), Trissaturated phenol (Tris-Phen), Phenol/SDS and Direct lysis method. After silver staining, different patterns of protein spots were observed in the gels. Results: Few spots were found by SDS and Phenol/SDS extractions, more spots by immediate dissolution but the most impurities, less protein productivity though more spots by Tris-Phen extractions, and more protein productivity and better apart effect by TCA/acetone. The 2-DE image background was the clear and the protein spots were the most by TCA/acetone method. Conclusion: TCA/acetone method is much more suitable as extraction method for protein two-dimensional electrophoresis of tomato flower buds.