Figure 3.

Interactions between NK and Raji cells lead to an upregulation of Siglec-7 ligands on Raji cells. (a) SNA staining of α2–6-sialic acids on Raji cells. (b, c) MFI of SNA (b) and MAA (c) lectin staining of Raji cells. (d, e) Transfer of SiaNAl-labeled sialosides from NK-92MI cells to Raji cells upon the coculture of both cells. (f, g) Ac₄ManNAl-based metabolic glycan labeling of Raji cells in the coculture with NK-92MI-S7 cells, in the presence of dynasore, brefeldin A, or not. (h) Coculture with peripheral NK cells also significantly induced Raji cells increase sialylation levels, as revealed by Aci₄ManNAl labeling. (i) NK-induced upregulation of sialylation on Raji cells further significantly increased the binding of Siglec-7-Fc. The relative Siglec-7 binding was determined via a division to the corresponding Fc controls stained with anti-human Fc-APC. (b, c, e, g-I) Bars represent the standard error of the MFI of three biological repeats of samples. The significance was analyzed with the two-sided Student’s t test. (*) p < 0.05; (***) p < 0.005; (****) p < 0.001.