Regeneration of membrane sialic acid after neuraminidase treatment of leukemic granulocytes

Abstract

Granulocytes from patients with chronic myelogenous leukemia (CML) were studied for their ability to regenerate surface sialic acid following treatment with Vibrio cholera neuraminidase (VCN) in vitro. Immediately after neuraminidase treatment, CML and normal granulocytes showed similar incorporation of radioactivity after surface labelling with sodium periodate/potassium-H 3-borohydride (PI/BH 3 4). CML granulocytes treated with neuraminidase then incubated for 18 h in nutrient medium showed strikingly increased PI/BH 3 4 labelling, usually greater than initial pretreatment values, consistent with a rapid reappearance of sialic acid in the cell membrane. This pattern was not seen in normal granulocytes. The aberrant regeneration of sialic acid in CML granulocytes in vitro could be inhibited by addition of 3 × 10 −6 M retinoic acid, suggesting either a direct effect on membrane glycoconjugate synthesis or an association with granulocyte differentiation.