Construction,expression of I-Ad/IgG2b Fc dimer fusion protein and its identification / 中国免疫学杂志

ABSTRACT

Objective:To construct I-Ad/IgG2b Fc baculovirus expression vector and express I-Ad/IgG2b Fc dimer fusion protein in Sf9 insect cells.Methods:I-Ad α,I-Ad β and IgG2b Fc gene sequences were amplified from BALB/c mouse lymphocytes by RT-PCR.I-Ad α and I-Ad β were connected with the leucine zipper sequence Fos and Jun respectively by overlapping PCR to form I-Ad α-Fos and I-Ad β-Jun.I-Ad α-Fos and IgG2b Fc fragments were ligated by restriction sites Xba I to form I-Ad α-Fos-IgG2b Fc recombination sequence.I-Ad α-Fos-IgG2b Fc and I-Ad β-Jun fragments were inserted to PPH and PP10,which were the downstream of the promoters in the plasmid pFastBacTMDual,to form pFastBacTMDual+[I-Ad/IgG2b Fc] recombinant plasmids.The constructed vector was identified by PCR,restriction endonuclease and sequencing.The recombinant plasmids pFastBacTMDual+[I-Ad/IgG2b Fc] was transferred into the DH10Bac competent cell to form recombinant baculovirus Bacmid+[I-Ad/IgG2b Fc].The recombinant baculovirus was transfected into Sf9 insect cells by liposome transfection reagent.After infected with Sf9 insect cells,the supernatant was collected and concentrated by PEG20000 to obtain I-Ad/IgG2b Fc dimer fusion protein.The fusion protein was detected by double-antibody sandwich ELISA and Western blot.Results:PCR,restriction enzyme digestion and sequencing confirmed that the recombinant vector pFastBacTMDual+[I-Ad/IgG2b Fc] had the correct sequence.The double antibody sandwich ELISA and Western blot showed that recombinant bacmid could successfully infect Sf9 insect cells,and the expressed fusion protein had the correct conformation.Conclusion:The pFastBacTMDual+[I-Ad/IgG2b Fc] baculovirus expression vector was successfully constructed and expressed in Sf9 insect cells,laying a foundation for the study of I-Ad-restricted T cells.