FIG 3.

The Siglec-7⁺ CD56^dim NK subpopulation exhibits higher SARS-CoV-2-specific direct cytolytic and ADCC activity than does the Siglec-7^– CD56^dim NK subpopulation. (A to C) Direct cytotoxicity-mediated degranulation and/or cytokine production of the Siglec-7⁺ and Siglec-7^– CD56^dim NK cells within each COVID-19 status group as assessed by the percentage of cells expressing (A) CD107a, (B) TNF-α, and (C) CD107a and TNF-α. (D to I) ADCC-mediated degranulation and/or cytokine production of the Siglec-7⁺ and Siglec-7^– CD56^dim NK cells within each COVID-19 status group as assessed by the percentage of cells expressing (D) CD107a, (E) IFN-γ, (F) TNF-α, (G) CD107a and IFN-γ, (H) CD107a and TNF-α, or (I) IFN-γ and TNF-α. Wilcoxon’s signed-rank tests were used to compare the Siglec-7⁺ and Siglec-7^– CD56^dim NK cells within each disease group. (J) Spearman’s correlation heat-map showing associations between direct cytotoxicity- and ADCC-mediated NK degranulation of the Siglec-7⁺ and Siglec-7^– CD56^dim NK cells and plasma N-antigen load. Square color represents correlation strength, with blue representing negative correlations and red representing positive correlations; only samples from COVID-19-positive donors were used (n = 33).