Stimulatory function of peroxiredoxin 1 in activating adaptive humoral immunity in a zebrafish model

Peroxiredoxin 1 (Prdx1/Prx1), a ubiquitous antioxidant enzyme involved in preventing oxidative damage and maintaining redox homeostasis, is essential for various cellular activities. Extracellular Prdx1 also plays important roles in innate immune responses. However, little is known about the regulatory functions of Prdx1 in adaptive immunity. In the present study, we report the stimulatory role of Prdx1 in the initiation of adaptive humoral immunity in a zebrafish model. Administration of Prdx1 protein to zebrafish significantly induced the expression of TNF-α, IL-1β, and IL-6 by the Toll-like-receptor-4a-mediated NF-κB signaling pathway and enhanced the activation of MHC-II+ antigen-presenting cells, CD4+ T cells, and mIgM+ B cells. Subsequently, increased production of antigen-specific IgM antibody was observed. Thus, Prdx1 can be used as a novel molecular adjuvant with great therapeutic value for the vaccination of fish diseases. Our study improved the understanding of the biology of Prdx1 family.