Effect of monosaccharides on epitope expression and P-selectin–binding function. The effect of fully acetylated natural monosaccharide (GalNAc) or monosaccharide analog (4F-GalNAc, 4F-GlcNAc) added to HL-60 cells during their exponential growth phase was assessed in terms of P-selectin–binding function (A,E,I), (2) CLA/HECA expression (B,F,J), PSGL-1 expression (C,G,K), and DSA-binding efficiency (D,H,L). Neuraminidase was used to remove cell surface sialic acids and selectin-binding function at t = 0 hours in panels A through H, but not panels I through L. P-selectin binding (A), CLA/HECA expression (B), and DSA binding (D) returned to baseline levels (denoted by 100%) after removal of neuraminidase. 4F-GalNAc was more effective than 4F-GlcNAc in reducing P-selectin binding (E), CLA/HECA expression (F), and DSA binding (H). Control monosaccharide GalNAc behaved similarly to vehicle (DMSO) control. Results similar to those shown in panels E-H were observed when HL-60 cells were treated with modified sugars in the absence of neuraminidase treatment at t = 0 hours (I-L). Data are percentages with respect to HL-60 cells treated with vehicle control and no neuraminidase. n.d. indicates not done. *P < .05 with respect to vehicle control.