Analysis of DC Functions Using CD205-DTR Knock-In Mice

Area of Science:

• Immunology
• Cell Biology

Background:

• Dendritic cells (DCs) are key antigen-presenting cells (APCs) with diverse subsets, including conventional DCs (cDCs) and plasmacytoid DCs (pDCs).
• CD205, a C-type lectin, is primarily found on CD8α(+) cDCs, but its role in immune regulation in vivo remains largely unknown.

Purpose of the Study:

• To investigate the in vivo function of CD205-expressing conventional DCs (CD205+ cDCs) in adaptive immune responses.
• To develop a model for selective depletion of CD205+ cDCs to study their contribution to T cell priming and immunity.

Main Methods:

• Generation of knock-in (KI) mice expressing diphtheria toxin receptor (DTR) under the Cd205 gene promoter for conditional CD205+ cDC ablation.
• Utilized bone marrow chimeric mice, diphtheria toxin administration for DC depletion, and assessed depletion efficiency.
• Employed in vivo cross-presentation assays, cytotoxic T lymphocyte (CTL) generation assays, and antibacterial immunity assays.

Main Results:

• Conditional ablation of CD205+ cDCs significantly impaired antigen-specific priming of CD8+ T cells via cross-presentation of soluble antigens.
• CD205+ cDCs were essential for generating antibacterial CTLs, contributing to pathogen elimination during microbial infection.
• The study provides detailed protocols for generating chimeric mice, depleting CD205+ DCs, and evaluating their functional capacity.

Conclusions:

• CD205+ cDCs play a critical role in initiating CD8+ T cell responses through cross-presentation, particularly for generating CTLs against soluble antigens.
• These DCs are vital for effective antibacterial immunity, highlighting their importance in adaptive anti-pathogen responses.
• The developed mouse model and protocols enable further investigation into the specific functions of CD205+ cDCs in various immune contexts.