To further assess whether a lack of the N-terminal β-sheet affects the role of Prx4 in the immune response against bacterial challenge, four groups of healthy large yellow croakers were injected intramuscularly with Prx4, Prx4ΔN62, Prx4ΔN67, Prx4C113S, or 0.85% NaCl, followed by infection with the bacterial mixture. Here, PRDX4 is linked to infection.