Expression of a recombinant protein by fusing anti-CD20 ScFv with dominant antigen epitopes and its anti-tumor activity / 中国免疫学杂志

ABSTRACT

Objective:To artificially design and express a recombinant protein named as ScFv-pLLO by fusing ScFv gene of Rituximab(C2B8)and dominant antigen epitopes from listeriolysin O(LLO),and studying its anti-tumor activity.Methods:VH and VL gene sequences of C2B8 against CD20 were acquired by searching United States Patent database,and ScFv sequence was constructed by linking VL and VH with a short peptide linker.Two CD4+T cell epitopes from LLO were selected and designed to splice ScFv sequence.The recombinant gene of ScFv-pLLO was cloned into prokaryotic expression vector and purified after induction.The capacity of ScFv-pLLO target-binding to B-cell lymphomas was evaluated by flow cytometry ( FCM ) and co-immunoprecipitation ( Co-IP ) .The effects of ScFv-pLLO on B-cell lymphomas proliferation and apoptosis were detected respectively.The immunogenicity of ScFv-pLLO was assessed by lymphocyte proliferation assay.Results: ScFv-pLLO was successfully expressed.It could bind to different B-cell lymphomas cell lines and obviously inhibit the growth of Raji cells as well as inducing apoptosis.Moreover,ScFv-pLLO was able to stimulate proliferation of spleen lymphocytes of immunized mice.Conclusion: The recombinant protein ScFv-pLLO can target-bind to B-cell lymphomas,and perform inhibitory effect and induce apoptosis on Raji cells that indicate ScFv-pLLO retain the capacity of ScFv derived from monoclonal antibody against CD20.Besides, ScFv-pLLO can induce immune response.This study provides a basis for further research about the role of ScFv-pLLO on simulating tumor cell antigens as well as being tumor vaccine adjuvant.