ORIGINAL RESEARCH article
Front. Immunol.
Sec. Comparative Immunology
Volume 16 - 2025 | doi: 10.3389/fimmu.2025.1633701
This article is part of the Research TopicDeciphering Fish Immune Responses: Cellular Roles and Pathogen RecognitionView all 4 articles
Single-Cell Transcriptomics Unveils Leukocyte Heterogeneity in the Gills of Larimichthys crocea in Response to Parasitic Infection
Provisionally accepted
- 1Shantou University, Shantou, China
- 2Fujian Agriculture and Forestry University, Fuzhou, China
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Background: Fish gills serve as critical immune interfaces against aquatic pathogens, yet their leukocyte heterogeneity in response to parasitic infections remains poorly understood.Methods: Single-cell RNA sequencing was employed to elucidate leukocyte responses in the gills of Larimichthys crocea during Cryptocaryon irritans infection.Results: A total of 13,070 leukocytes from the gills under steady-state and infected conditions were profiled and classified into eight principal lineages: T cells (> 70% of total immune cells), ILC2-like cells, NK-like cells, neutrophils, cpa5 + granulocytes, B cells, macrophages, and dendritic cells. Following infection, T cell subsets exhibited distinct responses: Regulatory T cells expanded and demonstrated immunoregulatory capacity; CD8 + T cells exhibited cytotoxic responses; CD4 -CD8 -T cells displayed Th17-like functions; and γδ T cells showed Th2-like activity. ILC2-like cells significantly increased in abundance and upregulated type 2 cytokine expression, whereas cytotoxic NK-like cells enhanced chemokine signaling and cytotoxicity.Neutrophils increased in number and oxidative activity, while cpa5 + granulocytes highlighted immunomodulatory functions. Macrophages, dendritic cells, and B cells exhibited compartmentalized activation states, upregulating gene modules associated with pathogen recognition, antigen processing/presentation, chemotactic activity, and antibody defenses.Conclusions: These findings describe a multi-layered immune cell defense strategy in the gills of teleosts against parasitic infection, showing conserved and fish-specific adaptations. Understanding gill immunity provides viable targets for enhancing parasite resistance in aquaculture, such as modulating ILC2/Treg pathways to prevent infections.
Keywords: gill immunity, Larimichthys crocea, Single-cell transcriptomics, Cryptocaryon irritans, immune cell heterogeneity
Received: 23 May 2025; Accepted: 18 Jul 2025.
Copyright: © 2025 Li, Wang, Li, Tran, Ao, Li and Chen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Shengkang Li, Shantou University, Shantou, China
Xinhua Chen, Fujian Agriculture and Forestry University, Fuzhou, China
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