[Expression of plasmid pcDNA3-gtfB in mammalian cell]

This study aimed at investigating the transcription and expression of recombined plasmid pcDNA3-gtfB which encoding multiple glucosyltransferase-B antigenic gene, and the feasibility of the pcDNA3-gtfB used as gene vaccine.

The pcDNA3-gtfB was transfected into mammalian cell COS-1 with liposome. The total RNA of COS-1 cell transfected by pcDNA3-gtfB was extracted and purified. Using the total RNA as template, the transcription of pcDNA3-gtfB was assayed by reverse transcription polymerase chain reaction (RT-PCR). The expression product of pcDNA3-gtfB was identified with 5% SDS-PAGE, and then assayed using Western-blotting. The expression product of pcDNA3-gtfB was also assayed by using LSAB method, and cell transfected by pcDNA3 as the negative control.

Identified by agarose gel electrophoresis, the target gene fragment had the same molecular size (3.6 kb) as it was predicted, and it indicated that pcDNA-3gtfB was correctly transcribed into mammalian cells. Proved by SDS-PAGE, the molecular weight of the expression product (116-212 kD) was also the same as it was supposed to be. It was also indicated by Western-blotting and LSAB assay that the expression product induced immunizing response.

As gene vaccine, it is importance that the recombined plasmid could be correctly transcribed and expressed in mammalian cells. It was suggested by RT-PCR, LSAB and Western-blotting that recombined plasmid pcDNA3-gtfB could be correctly transcribed and expressed in mammalian cells, and the expression product could induce immunizing response, which support its use as gene vaccine candidates in the development of anticaries vaccines.