Interleukin 1 receptor type I (IL-1RI) is involved in the innate immune response of olive flounder (Paralichthys olivaceus) to resist pathogens

Abstract

The pleiotropic cytokine IL -1 is involved in important immune responses such as thymocyte proliferation and B cell growth and differentiation. Activation of the IL -1 pathway requires its functional receptor IL -1RI, making IL -1RI the critical point of the IL -1 pathway. In-depth study of IL -1RI will help to understand the immune mechanism involved in IL -1. In this study, we identified the cDNA of the IL -1RI gene of olive flounder (PoIL-1RI). The total length of the PoIL-1RI cDNA is 2490 bp, the open reading frame is 1689 bp long and encodes a protein of 562 amino acids. The protein has three Ig domains and a typical TIR domain, as in other mammals and fish. We found that PoIL-1RI is widely expressed in the tissues studied and shows a significant immune response after stimulation with bacteria and pathogen-associated molecular patterns (PAMPs) both in vitro and in vivo. After PoIL-1RI was overexpressed in olive flounder embryonic cell line (FEC), pro-inflammatory cytokines (IL -1β, IL -6, IL -8, TNF-α) and interferon (IFN-α, IFN-γ) were significantly upregulated. And we found that after overexpressing PoIL-1RI in FEC, the antibacterial ability of FEC was significantly stronger than that of the control group, and we found that overexpression of PoIL-1RI gene significantly increased the activity of NF-κB signaling pathway. These results suggest that PoIL-1RI plays an important role in innate immune response.

Keywords: Immune response; Innate immunity; Interleukin 1 receptor type I; Paralichthys olivaceus; Resisting pathogens.