Evaluation on the Efficacy and Immunogenicity of Recombinant DNA Plasmids Expressing Spike Genes from Porcine Transmissible Gastroenteritis Virus and Porcine Epidemic Diarrhea Virus

Meng, Fandan; Ren, Yudong; Suo, Siqingaowa; Sun, Xuejiao; Li, Xunliang; Li, Pengchong; Yang, Wei; Li, Guangxing; Li, Lu; Schwegmann-Wessels, Christel; Herrler, Georg; Ren, Xiaofeng

Assays for neutralizing anibodies against PEDV ( Figure 8A ) showed a concentration-dependent decrease of the inhibitory activity in sera of mice immunized by pIRES-(PEDV-S1), pIRES-(PEDV-S), pIRES-(TGEV-S1-PEDV-S1) and pIRES-(TGEV-S1-PEDV-S); higher titers were determined in sera from mice immunized with pIRES-(PEDV-S) and pIRES-(TGEV-S1-PEDV-S) constructs as compared to animals injected with pIRES-(PEDV- Figure 4 . Changes in T lymphocyte numbers in the spleens and peripheral blood of immunized mice. The proliferation of T lymphocytes in mouse spleens (A and B) and peripheral blood (C and D) was analyzed by conventional MTT assays using recombinant PEDV-S1 (A and C), TGEV-S1 (B and D) protein and Con A as stimulating agents. The y-axis represents the lymphocyte proliferation index (OD 490 ) in the spleen or peripheral blood. w: p,0.01 (highly significant) compared with PBS group and pIRES group. doi:10.1371/journal.pone.0057468.g004 S1) and pIRES-(TGEV-S1-PEDV-S1) constructs. Neutralizing antibodies against TGEV ( Figure 8B ) were also detected in mice immunized by pIRES-(TGEV-S1), pIRES-(TGEV-S1-PEDV-S1) and pIRES-(TGEV-S1-PEDV-S). Here, there were no pronounced differences detected between the three groups of animals.