The newborn human NK cell repertoire is phenotypically formed but functionally reduced

Area of Science:

• Immunology
• Neonatal Research
• Cell Biology

Background:

• Infections pose a significant global mortality risk for infants under one month old.
• There is a critical need for improved vaccines and therapeutics for neonates.
• Newborns primarily depend on their innate immune system for defense against pathogens.

Purpose of the Study:

• To compare the phenotype and function of natural killer (NK) cells from umbilical cord blood and adult peripheral blood.
• To assess the potential of NK cells as targets for neonatal vaccines and therapeutics.

Main Methods:

• Mass cytometry was employed for a comprehensive comparison of NK cells.
• Unsupervised analyses (viSNE, principal component analysis) were used to analyze cell populations.
• Functional assays assessed degranulation, cytokine production, antibody-dependent cell-mediated cytotoxicity, and apoptosis induction.

Main Results:

• The overall structure of NK cell repertoires in cord blood and adult blood is highly similar.
• Differences were mainly observed in maturity-related markers on rare NK cell subpopulations.
• Cord blood NK cells exhibited reduced functional responses, including degranulation and cytokine production, compared to adult NK cells.

Conclusions:

• The NK cell repertoire is structurally intact at birth, indicating its potential for therapeutic strategies.
• Despite structural integrity, functional deficits in neonatal NK cells warrant further investigation.
• These findings support the development of vaccines and therapeutics targeting NK cells to protect newborns from infection.