Construction and Expression of Eukaryotic and Prokaryotic Recombinant Vectors of Pepck and Gp63 Dominant Epitopes of Leishmania infantum

  Objective  To construct eukaryotic and prokaryotic recombinant vectors containing Pepck-Gp63 and to achieve protein expression by selecting the dominant epitope genes of Pepck and Gp63 of Leishmania infantum.

  Methods  The secondary structure and HLA epitopes of phosphoenolpyruvate carboxylase (PEPCK) were predicted by in silico analysis, and the dominant epitopes were picked out. According to the analysis results of glycoprotein of 63×10³ (GP63) epitopes identified by the same method in our laboratory, the dominant epitope genes of Pepck and Gp63 were used to construct pET32a-Pepck-Gp63 and pVAX1-Pepck-Gp63 by overlapping PCR and enzyme reaction. Then, for protein expression, the prokaryotic vectors were transfected into E.coil while the eukaryotic vectors were transfected into NIH3T3 cells by liposome transfection.

  Results  There were multiple dominant epitopes in Pepck and there were Pepck-Gp63 sequences in the polyclonal site of expression vector. The expression of Pepck-Gp63 in E.coil appeared in inclusion form and led to 74 kDa band in SDS-PAGE. The immunofluorescence results of NIH3T3 cells transfected by pVAX1-Pepck-Gp63 were positive.

  Conclusion  The recombinant prokaryotic expression plasmids pET32a-Pepck-Gp63 and eukaryotic expression plasmids pVAX1-Pepck-Gp63 were successfully constructed, and it was shown that the recombinant plasmids were able to express the corresponding target proteins in E. coli and NIH3T3 cells, respectively, providing a preliminary experimental basis for the subsequent study of immunization strategies.