FIG 2.

The Siglec-9⁺ CD56^dim NK subpopulation exhibits a higher SARS-CoV-2 specific ADCC than the Siglec-9^– CD56^dim NK subpopulation. (A to I) ADCC-mediated degranulation and/or cytokine production of the Siglec-9⁺ and Siglec-9^– CD56^dim NK cells within each COVID-19 status group as assessed by the percentage of cells expressing (A) CD107a, (B) IFN-γ, (C) TNF-α, (D) CD107a and IFN-γ, (E) CD107a and TNF-α, and (F) IFN-γ and TNF-α. The mean fluorescence intensity (MFI) was also evaluated for (G) CD107a, (H) IFN-γ, and (I) TNF-α. Wilcoxon’s signed-rank tests were used to compare the Siglec-9⁺ and Siglec-9^– CD56^dim NK cells within each COVID-19 status group. (J) Spearman’s correlation heat-map showing associations between direct cytotoxicity and ADCC-mediated NK degranulation of the Siglec-9⁺ and Siglec-9^– 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).