Fig 5. Partial protection of IFNAR KO mice after vaccination with Gn-Fc antigen.

(A) Anti-Gc (blue dots) or Gn (red dots) IgG response was measured by ELISA at two weeks after the third immunization with Gn-Fc or Gc-Fc in IFNAR KO mice (n = 4/group). Cut-off titers (dashed line, mean O.D. + 3 x S.D. at 1:100 diluents) was determined using Fc-immune sera (black dots). The antibody titers of anti-Gc or Gn IgG in sera of immunized mice are summarized in the right panel. Error bar, mean + S.D.; black line, mean. (B) Neutralizing antibody response to SFTSV generated by SFTSV DNA vaccines in IFNAR KO mice. The amount of neutralizing antibody against SFTSV was determined based on FRNT₅₀ (left panel) and summarized (right panel). (C) Survival rates (left panel) and body weight changes (right panel) of mice immunized three times with Fc (black dots, n = 6), Gc-Fc (blue dots, n = 4), or Gn-Fc (red dots, n = 6) antigen and challenged s.c. with 10⁵ FFU of SFTSV at two weeks after vaccination. *, p < 0.05; **, p < 0.01.