Objective  DNA vaccine vector of S and N genes of porcine transmissible gastroenteritis virus (TGEV) was constructed with the vaccine immunogenicity determined to pave the way for studying, preventing, and controling TGE.

Method  A and D sites on S and N from a TGEV were amplified. The N gene alone as well as the A and D sites fusion were cloned into the vaccine vector pCDNA3.1-His-C. Bioinformatics software was used to predict and analyze the secondary structure, tertiary configuration, subcellular localization, and dominant B cell epitope of S (A-D) and N proteins. The recombinant vectors were transfected into PK-15 cells, and expression distribution of N and the A and D sites fusion detected by indirect immunofluorescence and confocal detection. Mice were immunized with the single or combined recombinant vaccine vector to detect the IgG antibody using indirect ELISA.

Result  The A and D sites of the S were 498 bp and 606 bp, respectively, and the N, 1149 bp in length. The nucleic acid vaccine expression vectors p-S (A-D)-His and p-N-His for the A and D sites (fusion) and N were constructed. Bioinformatics software predicted that, when TGEV infected the host cells, N protein was mainly located in the nucleus and mitochondria and S (A-D) largely in the cytoplasm and mitochondria, while S (A-D) had 7 and N, 8 dominant B cell epitopes. All p-S (A-D)-His and p-N-His were successfully expressed in PK-15 cells distributed in the nucleus and cytoplasm. The immunized mice showed an effect of immunity in the order of p-N-His＞p-S (A-D)-His + p-N-His＞p-S (A-D)-His.

Conclusion The DNA vaccine vectors of S and N of TGEV were successfully constructed. Strong specific antibodies were generated in lab mice after the immunization.