Donor Variability and Seeding Density Shape NK-Cell Proliferation and Surface Receptor Expression: Insights from an...

Area of Science:

• Immunology
• Cell Biology
• Translational Medicine

Background:

• Natural killer (NK) cells are vital for adoptive immunotherapy.
• Clinical use necessitates standardized expansion protocols for sufficient, functional NK cells.

Purpose of the Study:

• To investigate how seeding density and donor variability impact NK cell expansion and receptor phenotype in vitro.
• To assess the role of genetic variations in NK cell receptor genes on expansion outcomes.

Main Methods:

• NK cells from healthy donors were expanded in G-Rex plates with IL-2.
• Longitudinal analysis using flow cytometry assessed cell proliferation and receptor expression.
• Targeted SNP sequencing of key receptor genes (IL2RA, IL2RB, FCGR3A, NCR1, KLRK1, ICAM-1) was performed.

Main Results:

• A seeding density of 2.0 × 10^6 cells/cm^2 favored high expansion and expression of activating receptors (CD16a, NKp46, NKG2D).
• Significant inter-donor variability in proliferation and receptor expression was observed.
• Some donors showed impaired expansion linked to specific SNPs, while others had robust growth without clear genetic drivers, suggesting non-genetic factors.

Conclusions:

• Both culture conditions (seeding density) and donor-intrinsic factors significantly influence NK cell expansion.
• Integrating phenotypic and genetic analyses is key to improving reproducibility and personalization of NK cell manufacturing for therapy.