Dendritic Cells Display Subset and Tissue-Specific Maturation Dynamics over Human Life.

Area of Science:

• Immunology
• Cell Biology
• Human Anatomy

Background:

• Dendritic cell (DC) maturation and migration to lymph nodes (LNs) are crucial in immune responses but poorly understood in humans.
• Conventional dendritic cells (cDCs) are key antigen-presenting cells, with distinct subsets having specialized functions.

Purpose of the Study:

• To investigate the distribution, maturation, and migration patterns of human cDC subsets in mucosal tissues and associated LNs across a wide age range.
• To elucidate the lifelong roles and tissue-specific functions of human cDC1 and cDC2 subsets.

Main Methods:

• Analysis of cDC subset distribution and maturation markers (HLA-DR) in mucosal tissues (lungs, intestines) and LNs from 78 human organ donors (age <1 to 93 years).
• Utilized tissue-specific markers to trace the migratory origin of cDCs in LNs.

Main Results:

• cDC1 and cDC2 subset distribution varied by tissue site and was conserved across individuals.
• cDC2 were the predominant mature cDC subset in LNs, particularly abundant in lung-draining LNs.
• Mature cDC2 in mucosal LNs expressed markers reflecting their mucosal origin, indicating tissue-specific migration.

Conclusions:

• Human cDC subset distribution and maturation patterns are largely maintained throughout life, with site-specific variations.
• cDC2 cells act as lifelong guardians of mucosal tissues, performing localized surveillance.
• Findings reveal a lifelong division of labor among DC subsets in maintaining tissue immunity.