Development and function of chicken XCR1⁺ conventional dendritic cells.

Area of Science:

• Immunology
• Cell Biology
• Avian Biology

Background:

• Conventional dendritic cells (cDCs) are key antigen-presenting cells (APCs) bridging innate and adaptive immunity.
• Chicken cDCs are poorly characterized compared to mammalian counterparts.
• Understanding chicken cDCs is vital for avian immunology and disease resistance research.

Purpose of the Study:

• To characterize chicken splenic cDCs using advanced techniques.
• To investigate the heterogeneity and function of chicken cDCs.
• To establish a model for studying cDC function in chickens.

Main Methods:

• Single-cell RNA sequencing (scRNAseq) of chicken splenic cells.
• Generation of gene-edited chickens (XCR1-iCaspase9-RFP) using CRISPR-Cas9.
• Inducible ablation of XCR1+ cDCs and subsequent analysis.

Main Results:

• Identified a single XCR1-expressing cDC subset in the chicken spleen, abundant by sexual maturity.
• Revealed heterogeneity within XCR1+ cDCs, with immature cells expressing antiviral genes and mature cells upregulating antigen presentation genes.
• Demonstrated that XCR1+ cDCs associate with CD8+ T-cells, a process dependent on XCR1 expression.

Conclusions:

• Chicken splenic XCR1+ cDCs represent a conserved subset with critical roles in T-cell responses.
• These findings provide insights into the function of dendritic cells in avian immunity.
• The developed gene-editing tools enable further functional studies of cDCs in chickens.