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

Splenocytes from immunized mice were prepared for lymphocyte proliferation assays as described [22] . Prepared cells (50 ml of 2610 6 cells/ml) were suspended in RPMI1640 containing 10% serum then transferred to 96-well, flat-bottom plates. To each well, 50 ml of medium containing either 20 mg/ml purified recombinant TGEV-S1 and PEDV-S1 proteins or Concanavalin A (Sigma) was added; all treatments were performed in triplicate. Plates were incubated for 72 h, supplemented with 10 ml/well of 3-(4,5dimethylthylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT), then incubated for an additional 4 h. Reactions were terminated by adding an equal volume of DMSO and incubating the plates at room temperature for 10 min. Proliferation was measured by OD 490 values. Proliferation of T lymphocytes in PBMCs from vaccinated and control mice was similarly monitored.