Expression and serological application of recombinant epitope-repeat protein carrying an immunodominant epitope of Newcastle disease virus nucleoprotein

Gaikwad, Satish S.; Lee, Hyun-Jeong; Kim, Ji-Ye; Choi, Kang-Seuk

Bac-to-Bac expression system was used to produce a baculovirus encoding N-terminally 6× His tagged rERP protein un- der the transcriptional control of polyhedrin promoter. Recombinant baculovirus bac-rERP infected cells were lysed under denaturing conditions and rERP was purified using His tag purification. The protein was allowed to refold using refolding buffer. To identify the expressed rERP, the purified protein was analyzed by western blot assay. The chicken anti-NDV serum raised by infecting SPF chickens with La Sota strain of NDV [19] was used as the primary antibody in the analysis. The results showed purified rERP with molecular weight of approximately 20 kDa reacted specifically (lanes 1 to 6 in Fig. 2) to the NDV positive serum. No specific band was detected with negative controls (lanes N1 and N2 in Fig. 2) , which indicated that the rERP is expressed correctly, and has good reaction ability with chicken specific anti-NDV serum.