Enhancement of antigen-specific humoral immune responses and protein solubility through conjugation of bacterial flagellin, Vibrio vulnificus FlaB, to the N-terminus of porcine epidemic diarrhea virus surface protein antigen S0

Oh, Seo-ho; Kim Cho, Young-Saeng; Lee, Ho-Bin; Lee, Sang-Mok; Kim, Whee-Soo; Hong, Liang; Cho, Chong-Su; Choi, Yun-Jaie; Kang, Sang-Kee

For further experiments, we purified soluble lysates of each recombinant protein utilizing Ni 2+ -NTA affinity chromatography, subsequently removed endotoxins and confirmed through SDS-PAGE followed by Coomassie Blue staining ( Fig. 3A and C) . The representative band of each recombinant protein appeared at the appropriate molecular weight location in the IPTGinduced whole cell lysate lane (Lane 2 of Fig. 3A-C) compared with the IPTG noninduced whole cell lysate lane (lane 1 of Fig. 1A-C) . The purities of S0-F, F-S0 and F were 90.3%, 92.6% and 99%, respectively ( Table 2) . Due to the difficulty of purifying S0 as a soluble lysate, S0 insoluble aggregates were solubilized, refolded and subsequently purified as described previously [8] .