2.1 Cells, virus, bacteria and expression vector
Vero cells (ATCC CCL-81) were cultured in Dulbecco’s modified Eagle’s
medium (DMEM;
Life
Technologies, NY, USA) supplemented with 10% fetal bovine serum
(FBS;
Life Technologies), 100 U/ml penicillin G and 100 μg/ml streptomycin. A
G1 PEDV CV777 vaccine strain was kindly provided by Dr. Enjuanes,
Department of Molecular and Cell Biology, Campus Universidad Autonoma de
Madrid, Madrid, Spain. A G2 PEDV strain CH/ZMDZY/11 was isolated from
3-day-old piglets suffering from watery diarrhea and dehydration by our
laboratory (Wang et al., 2013). These piglets were generated by
CV777vaccince-immunized sows. pET-28a (+) plasmid was purchased from
Novagen (WI, USA).Escherichia coli DH5α and
BL21 (DE3) were used for cloning experiments and as a heterologous
expression host respectively.