Figure 1.
NK cell repertoire in CB is immature and less heterogeneous than in PB. (A) The manually pregated CD56+ NK cell populations were exported and down-sampled to an equal cell number of 2000 per sample. Individual t-SNE maps show the expression of 33 different NK cell markers. Color scale indicates signal intensity, ranging from low (blue) to high (red) after arcsine transformation. Bar plots under each t-SNE map depict the frequencies of NK cells expressing each marker in 10 CB (blue) vs 10 healthy PB (red) donors. *P ≤ .05; **P ≤ .01; ***P ≤ .001; **** P ≤ .0001. Bars represent median values with interquartile ranges. (B) SPADE analysis identified distinct clusters within CB (left) and PB (right) NK cell compartments. Phenotypically distinct CB and PB NK cell clusters occupy different regions of the SPADE tree. Node size and color scale represent the relative number of cells per node. (C) Cytotoxicity of resting healthy donor PB (red) and CB (blue) NK cells against K562 targets at different effector: target (E:T) ratios, as measured by 51Cr-release assay (n = 10). (D) Bar plots summarize the IFN-γ, TNF-α, and CD107A response to K562 targets by bead-purified PB (red) and CB (blue) NK cells (n = 10). **P ≤ .01; ***P ≤ .001. Bars represent median values with interquartile ranges. (E) Global gene expression analysis by RNA sequencing. Heat map displays 1073 genes that are differentially expressed (adjusted P < .01 with log2 fold change >1) in purified NK cells from CB (3 different donors) vs PB (6 different donors). (F) Volcano plot showing significantly differentiated genes (red dots) between CB and PB. (G) Heat map of differentially expressed genes as described by the indicated gene ontology (GO) terms. (H) Gene coexpression network construction was performed with Pearson’s correlation between the expression profiles of each module. The rows and columns represent each module in different color and number for each network construction. Color bar shows the correlation index. (I) Hub genes from each module of networks were displayed in 2 circles; the blue circle presents the CB, and the red circle represents the PB NK cell network. NS, not significant.