Tissue-Resident NK Cells: Development, Maturation, and Clinical Relevance

Area of Science:

• Immunology
• Cell Biology
• Innate Immunity

Background:

• Natural killer (NK) cells are type 1 innate lymphoid cells (ILC1) crucial for eliminating infected or transformed cells.
• Historically, NK cells were considered homogeneous due to conserved activating receptors, implying limited immune functions.
• Recent research indicates significant NK cell heterogeneity, with diverse subsets exhibiting varied immune functions.

Purpose of the Study:

• To explore the molecular basis, phenotypic signatures, and functions of tissue-resident NK cells.
• To compare tissue-resident NK cells with conventional NK cells.
• To highlight the role of tissue residency in NK cell heterogeneity and functional divergence.

Main Methods:

• Review of existing literature on NK cell development, receptors, and tissue residency.
• Analysis of molecular and phenotypic data differentiating NK cell subsets.
• Comparative study of conventional versus tissue-resident NK cell populations.

Main Results:

• NK cell heterogeneity is driven by distinct combinations of activating and inhibitory receptors.
• Tissue residency emerges as a critical factor influencing NK cell differentiation and function.
• Evidence suggests NK cells can develop and differentiate within tissues, not solely in the bone marrow.

Conclusions:

• NK cells exhibit remarkable functional diversity, challenging the dogma of homogeneity.
• Tissue-resident NK cells represent a distinct subset with unique characteristics and roles.
• Understanding tissue residency is key to fully appreciating NK cell biology and immune responses.