Contribution of C3d-P28 repeats to enhancement of immune responses against HBV-preS2/S induced by gene immunization

Figure 2 Semiquantitative RT-PCR for expression of the preS2/S-P28 fusion proteins. Lane 1: DNA marker; Lanes 2,3 and 5: RT-PCR with preS2/Ss and preS2/Sa primers that am-plified an entire coding region (858 bp) of preS2/S, using RNA extracted from pVAON33, pVAON33-S2/S and pVAON33-S2/S-P28.4 transfected-cells, respectively; Lanes 4 and 6: RT-PCR with preS2/Ss and P28a primers that amplified a 1230 bp cDNA fragment of preS2/S-P28.4 fusion cDNA (the ladder showed the RT-PCR production due to 4 copies of P28), using RNA extracted from pVAON33-S2/S and pVAON33-S2/S-P28.4 transfected-cells, respectively; Lanes 7 and 9: RNA extracted from pVAON33-S2/S and pVAON33-S2/S-P28.4 transfected-cells was founded to exclude the potential contamination of potential plasmid DNA by PCR with preS2/Ss and preS2/Sa primers, respectively; and Lane 8: pVAON33-S2/S plasmid DNA was taken as positive control.