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

Flagellin's adjuvant effect on the humoral immune response to PED antigen S0 was evaluated through mouse serum S0-specific IgG levels after immunization. Five groups of mice were immunized three times intramuscularly with PBS, 30 pmol of S0 (0.76 μg), S0-F (2 μg), F-S0 (2 μg) and a mixture of S0/F (0.76+1.24 μg) at 14-day intervals. Sera were collected at the 2nd, 4th and 6th weeks postinjection, and S0-specific IgG levels were evaluated by indirect ELISA (Fig. 4A) . Interestingly, the F-S0 immunized group had significantly higher levels of S0-specific IgG and IgA compared to all other groups on the 6th week ( Fig. 4D and E) . Sera collected at the 2nd and 4th week postinjection had a similar tendency as the 6th-week sera ( Fig. 4B and C) .