Study On The Expression Of Anti-human PD-L1 Monoclonal Antibody

Antibody drugs have the advantages of uniform nature,higher specificity and targeted preparation for specific targets,and have good clinical value in tumor immunotherapy.With the development of biotechnology,humanized antibodies have become the research focus of antibody drugs because of their advantages of reducing the body's immune rejection and long half-life in vivo.The combination of PD-1 and its ligand-1?PD-L1?can make tumor cells evade immune suppression.In recent years,blocking its pathway has become a new direction for cancer treatment.PD-1/PD-L1 antibody drugs have been shown to have a good effect in a variety of cancer treatments.In the previous work,our group completed the humanization of anti-PD-L1 antibody,obtained active PD-L1 antibody,and established a detection method.Based on the previous work,anti-PD-L1 antibody was transiently expressed by HEK293 adherent cells and its expression conditions were optimized.The expression level was0.561?g/m L,which is not high enough for mass production.In this study,we re-selected host cell HEK293 6E suitable for anti-PD-L1 antibody expression and constructed a anti-PD-L1 antibody expression vector to allow large-scale expression of the antibody in HEK293 6E.We also explored the conditions for expression.The results showed that the vectors of heavy chain?pTT5-H?and light chain?pTT5-L?were successfully constructed and the target protein could be detected in culture supernatant of co-transfected cells.Firstly,the culture medium was selected.Free Style^TM F17 and A serum-free growth liquids were more suitable as the growth medium for HEK293 6E cells.A medium was selected as the expression medium.The highest expression level of antibody protein on the fifth day was63.02?g/m L,which was significantly higher than that of the 1d group?P<0.001?.Then,we tested the expression conditions,while the mass ratio of DNA to PEI was 1:1,the highest level of antibody expression on day 3 was 170.9?g/m L.When the Feed was a 5%OPM-293 CD Feed,the highest expression level of anti-PD-L1 antibody was 159.8?g/m L on the 4th day.Finally,the molecular weight of the antibody heavy chain was approximately 50 kD as determined by SDS,and the light chain was approximately 25 kD.Meanwhile,we detected the activity of PD-L1 antibody,the results showed that the expressed anti-PD-L1 antibody had good activity,and it could meet the requirements in the latter antibody research.Furthermore,The anti-PD-L1 antibody expression system with low cost and convenient operation was successfully established.