[Construction and expression of human 4-1BBL/anti-CD20 fusion protein].

Aim: To construct and express human 4-1BBL/anti-CD20 bispecific fusion protein and identify its biological activity.

Methods: PCR and overlapping PCR were used to construct human 4-1BBL/anti-CD20 bispecific fusion protein. DNA sequencing was performed by the terminus of the fusion protein nucleotide.The product was purified by affinity chromatography and analyzed by Western blot and its antigen-binding activity was examined by FACS.

Results: The data of DNA sequence showed that human 4-1BBL/anti-CD20 bispecific fusion protein was correct. The fusion protein was recovered in high yield (up to 4 mg/L) after E-tag purification and predominantly(90%) as a dimer. The fusion protein could bind to Raji cells(CD20(+)) and A549 cells(4-1BB(+)), respectively.

Conclusion: The human 4-1BBL/anti-CD20 bispecific fusion protein with high level expression was successfully obtained and could bind to Raji ceIls and A549 cells.