Figure 5
In vivo immunoprotection assay of hepcidin-mediated antibacterial activity. (A) The survival rate of zebrafish upon A. hydrophila (A.h) infection (2.1 × 105 CFU per fish). The fish received various treatments before infection, including stimulation with A. hydrophila DNA (1.5 μg per fish, indicated as A.h DNA + A.h), administration of anti-hepcidin Ab for hepcidin neutralization (indicated as Hepcidin Ab + A.h), in which the non-specific rabbit IgG was administrated into the A. hydrophila DNA stimulated fish as a negative control (indicated as Non-specific IgG + A.h), and administration of mock PBS into the non-stimulated control fish (indicated as PBS + A.h). (B) The survival rate of zebrafish upon V. alginolyticus (V.a) infection (2.9 × 105 CFU per fish). The fish received various treatments before infection similar to that as described in Fig. 5A. The Mock fish (indicated as Mock in Fig. 5A and B) received only A. hydrophila DNA without infections. (C) Immunoprotective effect of hepcidin-mediated antibacterial immunity against V. alginolyticus infection determined by the alteration of lethal dose 50 (LD50) of V. alginolyticus that kills 50% of the test fish within a set amount of time (24 h). The control fish (indicated as Control) received only PBS before infections. The stimulated fish (indicated as Stimulated) received A. hydrophila DNA (1.5 μg per fish). At least 30 fish were used in each experimental group, and all data are representative of at least three independent experiments. *p < 0.05.
