Single-cell transcriptomic profiling of the chicken spleen reveals cell-type-specific immune responses to Salmonella infection.

Although the spleen is a key immune organ, the dynamic remodeling of its cellular landscape during development and the heterogeneous immune responses of these cells to avian Salmonella infection remain to be elucidated. In this study, we reanalyzed publicly available datasets comprising 116,791 single-cell transcriptomes from the chicken spleen. We annotated a total of 40 distinct cell types, systematically delineating the cellular composition and dynamic changes from embryonic to adult stages. Moreover, single-cell comparisons before and after Salmonella infection revealed markedly strengthened intercellular crosstalk within the lymphoid lineage and between lymphoid and myeloid lineages. Transcriptional analysis demonstrated that naive T cells, NK2 cells, and B cells underwent the most extensive transcriptional remodeling, implying their pivotal roles in the antibacterial immune response. Of note, the responses of different immune cell subsets displayed both subset-specific patterns and shared features. Furthermore, notable differences were detected in cellular interaction networks, as well as in the gene expression profiles of NK2 cells and activated T cells between different chicken breeds, which may serve as potential molecular mechanisms underlying the divergent disease resistance phenotypes among chicken breeds. Collectively, these findings provide a comprehensive temporal atlas​ of chicken splenic development and immunity, offering valuable insights into the molecular basis​ of disease resistance and laying a theoretical foundation for poultry breeding strategies.