Frontline defenses: advances in mucosal immunity across aquatic vertebrates

Mucosal surfaces represent the largest and most dynamic interfaces between animals and their environments, functioning as critical sites for immune surveillance, host–microbe interactions, and defense against invading pathogens. Across vertebrate and invertebrate taxa, barrier tissues such as the gills, gut, skin, and respiratory and reproductive epithelia are equipped with specialized immune cells, secreted effectors, and resident microbiota that collectively maintain homeostasis while mounting rapid responses to environmental challenges. Comparative immunology has revealed both conserved and lineage-specific strategies of mucosal defense, offering fundamental insights into the evolution and functional diversification of immune systems. In aquatic organisms, including fish and shellfish, these surfaces are continuously exposed to complex microbial communities and fluctuating environmental conditions, underscoring the importance of mucosal immunity for health and disease resistance. In aquaculture, where infectious diseases remain a major constraint to productivity and sustainability, a deeper understanding of mucosal immune mechanisms has important implications for vaccine development, disease prevention, and management practices.This Research Topic aims to advance the field of comparative mucosal immunology by bringing together new findings, methodological innovations, and integrative perspectives on barrier tissue immunity across diverse animal systems. We seek to highlight how mucosal tissues detect, regulate, and respond to pathogens, commensal microorganisms, and environmental stressors, and how these processes have evolved to meet distinct ecological and physiological demands. By fostering cross-species comparisons and interdisciplinary dialogue, this collection will promote a broader understanding of mucosal immune function and its translational applications in animal health, biotechnology, and sustainable food production.We invite original research articles, reviews, perspectives, and methodological papers that explore the cellular, molecular, ecological, and evolutionary dimensions of mucosal immunity in vertebrates and invertebrates. Contributions focused on aquatic species of biomedical, ecological, or aquacultural importance—including salmonids, tilapia, catfish, sea bass, crustaceans, and mollusks—are particularly welcome, as are studies that draw connections between model organisms and applied systems. Comparative and multidisciplinary approaches integrating immunology, microbiology, genomics, physiology, and host–microbe interactions are strongly encouraged.Topics of interest include, but are not limited to:- Cellular and molecular mechanisms of immunity at gill, gut, or skin surfaces- Mucosal vaccination strategies and adjuvant development- Microbiome–mucosal immune system interactions- Barrier responses to pathogens, parasites, pollutants, or environmental change- Innovations in sampling, imaging, and in situ analysis of mucosal tissues- Comparative studies of mucosal versus systemic immunity across aquaculture fish species- Evolutionary perspectives on mucosal defense mechanisms in aquatic vertebrates Topic editors: Mohamad Aslah Bin Mohamad, Gouranga Biswas, Shikha Saxena Source: https://www.frontiersin.org/research-topics/79950/frontline-defenses-advances-in-mucosal-immunity-across-aquatic-vertebrates