Monocytes of Malian adults upregulate markers of M2 regulatory monocytes/macrophages.

(A-E) PBMCs from Malian children (aged 4–6 years; n = 9) and adults (n = 9) before the malaria season, as well as healthy malaria-naïve U.S. adults (n = 7) were analyzed ex vivo by flow cytometry with gating on live monocytes for surface expression of CD14, CD16, CD163 and CD206. (A, B) t-SNE analysis of monocytes for all subjects in each group. Expression levels of each marker are indicated by color scales. (C) t-SNE analyzed data (shown in A and B) subjected to gating for monocyte subsets based on CD14 and CD16 expression using concatenated data from all subjects. MFI of (D) CD163 and (E) CD206 surface expression on manually gated live monocytes. (F, G) PBMCs were stimulated with Pf-iRBCs and analyzed for arginase-1 expression in monocytes intracellularly. (F) Representative t-SNE plots showing expression of Arginase-1 in the clusters in three different groups of monocytes. Expression of Arginase-1 is indicated by a color scale. (G). Expression MFI level of intracellular Arginase-1 on manually gated live monocytes comparing three different groups. Data were analyzed by the Mann-Whitney test with Bonferroni adjustment, and the level of significance between groups is indicated by P values.