Multi-tissue scRNA-seq reveals immune cell landscape of turbot (Scophthalmus maximus).

ABSTRACT

In vertebrates, bony fishes possess not only innate immune cells but also T and B cells that are equivalent to those in mammals. However, the precise sub-cluster of immune cells in teleost fish remains largely unknown. Herein, we developed a dynamic bacterial infection model in turbot (Scophthalmus maximus) and created a fish immune cell landscape (FICL) for a primary lymphoid organ (head kidney), a secondary lymphoid organ (spleen), and barrier tissues (gills and posterior intestine). Moreover, through comprehensive characterization of the expression profiles of 16 clusters, including dendritic cells-like (DCs-like), macrophages (MΦs), neutrophils, NK cells, as well as 12 sub-clusters of T and B cells, we found that CD8+ CTLs, CD4-CD8- T, Th17 and ILC3-2 like cells possess a bifunctional role associated with cytotoxicity and immunoregulation during bacterial infection. To our knowledge, these results could provide a useful resource for a better understanding of immune cells in teleost fish and could act as a comprehensive knowledge base for assessing the evolutionary mechanism of adaptive immunity in vertebrates.