Research Progress on Molecular Regulation of Antiviral Innate Immunity of Amphioxus

This paper systematically summarises the key scientific issues in the study of the antiviral innate immune system of amphioxus, highlighting the recent progress in the areas of diversity of pattern recognition receptors (PRRs), conservatism and innovativeness of signaling pathways, complexity of regulatory networks of effector molecules, and their evolutionary relevance to the vertebrate immune system. Through in-depth discussion of the molecular types, virus recognition specificity, and signalling cascade activation mechanism of amphioxus PRRs and spatial and temporal expression regulation of amphioxus effector molecules (e.g. antimicrobial peptides, interferon-inducible proteins), the multilevel defence strategy of its antiviral immune response was revealed by combining with the comparative immunology perspective. The study paid special attention to the synergistic mode of action of Toll-like receptors (TLRs) and Retinoic acid-inducible gene-Ⅰ-like receptors (RLRs), the inter-regulatory network of NF-κB and Interferon Regulatory Factor (IRF) transcription factors, and the molecular basis of the immune memory-like phenomenon. On this basis, this paper provides a theoretical explanation of the transitional position of the antiviral immune system of amphioxus in the evolution of vertebrate immunity, and prospectively suggests that future studies should focus on the horizontal expansion and functional differentiation of the immune gene family, the evolutionary trajectory of the epigenetic regulatory elements, and the driving mechanism of the evolution of immune adaptations by environmental stresses, which would provide a key empirical basis for the analysis of the molecular origins of the innate immune system in vertebrates.