Construction and immunogenicity prediction of Plasmodium falciparum CTL epitope minigene vaccine

The minigenes encoding Plasmodium falciparum CTL epitopes restricted to hum an MHC class I molecular HLA-A2 and HLA-B51, which were both at high freque ncy among Chinese population, were constructed as mono-epitope CTL vaccines named pcDNA3.1/tr and pcDNA3.1/sh. The minigenes of the two epitopes were then tandem linked to form a dimeric CTL epitope minigene recombinant vacci ne. After DNA transfection, the epitope minigenes were expressed respective ly in two human cell lines, each bearing one MHC class I molecule named CIR /HLA-A2.1 and K562/HLA-B51. The intracellular expression of the CTL epitope minigenes not only enhanced the stability of HLA-A2.1 and HLA-B51 molecule s but also increased the assemblage of MHC class I molecules on cell surfac es, which testified the specific process and presentation of those endogeno us expressed epitopes. For the cells transfected with the dimeric minigene encoding two tandem linked epitopes, the expression and presentation of eac h epitope were also detected on cell membranes that bore different MHC clas s I molecules. It meant that the adjacency of the two CTL epitopes did not interfere with the specific process and presentation of each epitope. Compa red with the ordinary CTL studies that inoculated synthesized epitope pepti des with peripheral blood cells, this work aimed to process the epitopes di rectly inside HLA class I allele specific human cells, and thus theoretical ly imitated the same procedure in vivo. It was also an economical way to pr edict the immunogenicity of CTL epitopes at an early stage especially in la boratories with limited financial resource.